fd.c File Reference

#include "postgres.h"
#include <dirent.h>
#include <sys/file.h>
#include <sys/param.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <limits.h>
#include <unistd.h>
#include <fcntl.h>
#include "access/xact.h"
#include "access/xlog.h"
#include "catalog/pg_tablespace.h"
#include "common/file_perm.h"
#include "common/file_utils.h"
#include "common/pg_prng.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "postmaster/startup.h"
#include "storage/aio.h"
#include "storage/fd.h"
#include "storage/ipc.h"
#include "utils/guc.h"
#include "utils/guc_hooks.h"
#include "utils/resowner.h"
#include "utils/varlena.h"

Include dependency graph for fd.c:

Go to the source code of this file.

Data Structures
struct	vfd
struct	AllocateDesc

Macros
#define	NUM_RESERVED_FDS   10
#define	FD_MINFREE   48
#define	DO_DB(A)    ((void) 0)
#define	VFD_CLOSED   (-1)
#define	FileIsValid(file)    ((file) > 0 && (file) < (int) SizeVfdCache && VfdCache[file].fileName != NULL)
#define	FileIsNotOpen(file)   (VfdCache[file].fd == VFD_CLOSED)
#define	FD_DELETE_AT_CLOSE   (1 << 0) /* T = delete when closed */
#define	FD_CLOSE_AT_EOXACT   (1 << 1) /* T = close at eoXact */
#define	FD_TEMP_FILE_LIMIT   (1 << 2) /* T = respect temp_file_limit */

Typedefs
typedef struct vfd	Vfd

Enumerations
enum	AllocateDescKind { AllocateDescFile , AllocateDescPipe , AllocateDescDir , AllocateDescRawFD }

Functions
static void	Delete (File file)
static void	LruDelete (File file)
static void	Insert (File file)
static int	LruInsert (File file)
static bool	ReleaseLruFile (void)
static void	ReleaseLruFiles (void)
static File	AllocateVfd (void)
static void	FreeVfd (File file)
static int	FileAccess (File file)
static File	OpenTemporaryFileInTablespace (Oid tblspcOid, bool rejectError)
static bool	reserveAllocatedDesc (void)
static int	FreeDesc (AllocateDesc *desc)
static void	BeforeShmemExit_Files (int code, Datum arg)
static void	CleanupTempFiles (bool isCommit, bool isProcExit)
static void	RemovePgTempRelationFiles (const char *tsdirname)
static void	RemovePgTempRelationFilesInDbspace (const char *dbspacedirname)
static void	walkdir (const char *path, void(*action)(const char *fname, bool isdir, int elevel), bool process_symlinks, int elevel)
static void	datadir_fsync_fname (const char *fname, bool isdir, int elevel)
static void	unlink_if_exists_fname (const char *fname, bool isdir, int elevel)
static int	fsync_parent_path (const char *fname, int elevel)
static void	ResOwnerReleaseFile (Datum res)
static char *	ResOwnerPrintFile (Datum res)
static void	ResourceOwnerRememberFile (ResourceOwner owner, File file)
static void	ResourceOwnerForgetFile (ResourceOwner owner, File file)
int	pg_fsync (int fd)
int	pg_fsync_no_writethrough (int fd)
int	pg_fsync_writethrough (int fd)
int	pg_fdatasync (int fd)
bool	pg_file_exists (const char *name)
void	pg_flush_data (int fd, pgoff_t offset, pgoff_t nbytes)
static int	pg_ftruncate (int fd, pgoff_t length)
int	pg_truncate (const char *path, pgoff_t length)
void	fsync_fname (const char *fname, bool isdir)
int	durable_rename (const char *oldfile, const char *newfile, int elevel)
int	durable_unlink (const char *fname, int elevel)
void	InitFileAccess (void)
void	InitTemporaryFileAccess (void)
static void	count_usable_fds (int max_to_probe, int *usable_fds, int *already_open)
void	set_max_safe_fds (void)
int	BasicOpenFile (const char *fileName, int fileFlags)
int	BasicOpenFilePerm (const char *fileName, int fileFlags, mode_t fileMode)
bool	AcquireExternalFD (void)
void	ReserveExternalFD (void)
void	ReleaseExternalFD (void)
static void	ReportTemporaryFileUsage (const char *path, pgoff_t size)
static void	RegisterTemporaryFile (File file)
File	PathNameOpenFile (const char *fileName, int fileFlags)
File	PathNameOpenFilePerm (const char *fileName, int fileFlags, mode_t fileMode)
void	PathNameCreateTemporaryDir (const char *basedir, const char *directory)
void	PathNameDeleteTemporaryDir (const char *dirname)
File	OpenTemporaryFile (bool interXact)
void	TempTablespacePath (char *path, Oid tablespace)
File	PathNameCreateTemporaryFile (const char *path, bool error_on_failure)
File	PathNameOpenTemporaryFile (const char *path, int mode)
bool	PathNameDeleteTemporaryFile (const char *path, bool error_on_failure)
void	FileClose (File file)
int	FilePrefetch (File file, pgoff_t offset, pgoff_t amount, uint32 wait_event_info)
void	FileWriteback (File file, pgoff_t offset, pgoff_t nbytes, uint32 wait_event_info)
ssize_t	FileReadV (File file, const struct iovec *iov, int iovcnt, pgoff_t offset, uint32 wait_event_info)
int	FileStartReadV (PgAioHandle *ioh, File file, int iovcnt, pgoff_t offset, uint32 wait_event_info)
ssize_t	FileWriteV (File file, const struct iovec *iov, int iovcnt, pgoff_t offset, uint32 wait_event_info)
int	FileSync (File file, uint32 wait_event_info)
int	FileZero (File file, pgoff_t offset, pgoff_t amount, uint32 wait_event_info)
int	FileFallocate (File file, pgoff_t offset, pgoff_t amount, uint32 wait_event_info)
pgoff_t	FileSize (File file)
int	FileTruncate (File file, pgoff_t offset, uint32 wait_event_info)
char *	FilePathName (File file)
int	FileGetRawDesc (File file)
int	FileGetRawFlags (File file)
mode_t	FileGetRawMode (File file)
FILE *	AllocateFile (const char *name, const char *mode)
int	OpenTransientFile (const char *fileName, int fileFlags)
int	OpenTransientFilePerm (const char *fileName, int fileFlags, mode_t fileMode)
FILE *	OpenPipeStream (const char *command, const char *mode)
int	FreeFile (FILE *file)
int	CloseTransientFile (int fd)
DIR *	AllocateDir (const char *dirname)
struct dirent *	ReadDir (DIR *dir, const char *dirname)
struct dirent *	ReadDirExtended (DIR *dir, const char *dirname, int elevel)
int	FreeDir (DIR *dir)
int	ClosePipeStream (FILE *file)
void	closeAllVfds (void)
void	SetTempTablespaces (Oid *tableSpaces, int numSpaces)
bool	TempTablespacesAreSet (void)
int	GetTempTablespaces (Oid *tableSpaces, int numSpaces)
Oid	GetNextTempTableSpace (void)
void	AtEOSubXact_Files (bool isCommit, SubTransactionId mySubid, SubTransactionId parentSubid)
void	AtEOXact_Files (bool isCommit)
void	RemovePgTempFiles (void)
void	RemovePgTempFilesInDir (const char *tmpdirname, bool missing_ok, bool unlink_all)
bool	looks_like_temp_rel_name (const char *name)
void	SyncDataDirectory (void)
int	fsync_fname_ext (const char *fname, bool isdir, bool ignore_perm, int elevel)
int	MakePGDirectory (const char *directoryName)
int	data_sync_elevel (int elevel)
bool	check_debug_io_direct (char **newval, void **extra, GucSource source)
void	assign_debug_io_direct (const char *newval, void *extra)

Variables
int	max_files_per_process = 1000
int	max_safe_fds = FD_MINFREE
bool	data_sync_retry = false
int	recovery_init_sync_method = DATA_DIR_SYNC_METHOD_FSYNC
int	file_extend_method = DEFAULT_FILE_EXTEND_METHOD
int	io_direct_flags
static Vfd *	VfdCache
static Size	SizeVfdCache = 0
static int	nfile = 0
static bool	have_xact_temporary_files = false
static uint64	temporary_files_size = 0
static int	numAllocatedDescs = 0
static int	maxAllocatedDescs = 0
static AllocateDesc *	allocatedDescs = NULL
static int	numExternalFDs = 0
static long	tempFileCounter = 0
static Oid *	tempTableSpaces = NULL
static int	numTempTableSpaces = -1
static int	nextTempTableSpace = 0
static const ResourceOwnerDesc	file_resowner_desc

Macro Definition Documentation

DO_DB

#define DO_DB

(

A

)

((void) 0)

Definition at line 183 of file fd.c.

{
    int         fd;             /* current FD, or VFD_CLOSED if none */
    unsigned short fdstate;     /* bitflags for VFD's state */
    ResourceOwner resowner;     /* owner, for automatic cleanup */
    File        nextFree;       /* link to next free VFD, if in freelist */
    File        lruMoreRecently;    /* doubly linked recency-of-use list */
    File        lruLessRecently;
    pgoff_t     fileSize;       /* current size of file (0 if not temporary) */
    char       *fileName;       /* name of file, or NULL for unused VFD */
    /* NB: fileName is malloc'd, and must be free'd when closing the VFD */
    int         fileFlags;      /* open(2) flags for (re)opening the file */
    mode_t      fileMode;       /* mode to pass to open(2) */
} Vfd;
 
/*
 * Virtual File Descriptor array pointer and size.  This grows as
 * needed.  'File' values are indexes into this array.
 * Note that VfdCache[0] is not a usable VFD, just a list header.
 */
static Vfd *VfdCache;
static Size SizeVfdCache = 0;
 
/*
 * Number of file descriptors known to be in use by VFD entries.
 */
static int  nfile = 0;
 
/*
 * Flag to tell whether it's worth scanning VfdCache looking for temp files
 * to close
 */
static bool have_xact_temporary_files = false;
 
/*
 * Tracks the total size of all temporary files.  Note: when temp_file_limit
 * is being enforced, this cannot overflow since the limit cannot be more
 * than INT_MAX kilobytes.  When not enforcing, it could theoretically
 * overflow, but we don't care.
 */
static uint64 temporary_files_size = 0;
 
/* Temporary file access initialized and not yet shut down? */
#ifdef USE_ASSERT_CHECKING
static bool temporary_files_allowed = false;
#endif
 
/*
 * List of OS handles opened with AllocateFile, AllocateDir and
 * OpenTransientFile.
 */
typedef enum
{
    AllocateDescFile,
    AllocateDescPipe,
    AllocateDescDir,
    AllocateDescRawFD,
} AllocateDescKind;
 
typedef struct
{
    AllocateDescKind kind;
    SubTransactionId create_subid;
    union
    {
        FILE       *file;
        DIR        *dir;
        int         fd;
    }           desc;
} AllocateDesc;
 
static int  numAllocatedDescs = 0;
static int  maxAllocatedDescs = 0;
static AllocateDesc *allocatedDescs = NULL;
 
/*
 * Number of open "external" FDs reported to Reserve/ReleaseExternalFD.
 */
static int  numExternalFDs = 0;
 
/*
 * Number of temporary files opened during the current session;
 * this is used in generation of tempfile names.
 */
static long tempFileCounter = 0;
 
/*
 * Array of OIDs of temp tablespaces.  (Some entries may be InvalidOid,
 * indicating that the current database's default tablespace should be used.)
 * When numTempTableSpaces is -1, this has not been set in the current
 * transaction.
 */
static Oid *tempTableSpaces = NULL;
static int  numTempTableSpaces = -1;
static int  nextTempTableSpace = 0;
 
 
/*--------------------
 *
 * Private Routines
 *
 * Delete          - delete a file from the Lru ring
 * LruDelete       - remove a file from the Lru ring and close its FD
 * Insert          - put a file at the front of the Lru ring
 * LruInsert       - put a file at the front of the Lru ring and open it
 * ReleaseLruFile  - Release an fd by closing the last entry in the Lru ring
 * ReleaseLruFiles - Release fd(s) until we're under the max_safe_fds limit
 * AllocateVfd     - grab a free (or new) file record (from VfdCache)
 * FreeVfd         - free a file record
 *
 * The Least Recently Used ring is a doubly linked list that begins and
 * ends on element zero.  Element zero is special -- it doesn't represent
 * a file and its "fd" field always == VFD_CLOSED.  Element zero is just an
 * anchor that shows us the beginning/end of the ring.
 * Only VFD elements that are currently really open (have an FD assigned) are
 * in the Lru ring.  Elements that are "virtually" open can be recognized
 * by having a non-null fileName field.
 *
 * example:
 *
 *     /--less----\                /---------\
 *     v           \              v           \
 *   #0 --more---> LeastRecentlyUsed --more-\ \
 *    ^\                                    | |
 *     \\less--> MostRecentlyUsedFile   <---/ |
 *      \more---/                    \--less--/
 *
 *--------------------
 */
static void Delete(File file);
static void LruDelete(File file);
static void Insert(File file);
static int  LruInsert(File file);
static bool ReleaseLruFile(void);
static void ReleaseLruFiles(void);
static File AllocateVfd(void);
static void FreeVfd(File file);
 
static int  FileAccess(File file);
static File OpenTemporaryFileInTablespace(Oid tblspcOid, bool rejectError);
static bool reserveAllocatedDesc(void);
static int  FreeDesc(AllocateDesc *desc);
 
static void BeforeShmemExit_Files(int code, Datum arg);
static void CleanupTempFiles(bool isCommit, bool isProcExit);
static void RemovePgTempRelationFiles(const char *tsdirname);
static void RemovePgTempRelationFilesInDbspace(const char *dbspacedirname);
 
static void walkdir(const char *path,
                    void (*action) (const char *fname, bool isdir, int elevel),
                    bool process_symlinks,
                    int elevel);
#ifdef PG_FLUSH_DATA_WORKS
static void pre_sync_fname(const char *fname, bool isdir, int elevel);
#endif
static void datadir_fsync_fname(const char *fname, bool isdir, int elevel);
static void unlink_if_exists_fname(const char *fname, bool isdir, int elevel);
 
static int  fsync_parent_path(const char *fname, int elevel);
 
 
/* ResourceOwner callbacks to hold virtual file descriptors */
static void ResOwnerReleaseFile(Datum res);
static char *ResOwnerPrintFile(Datum res);
 
static const ResourceOwnerDesc file_resowner_desc =
{
    .name = "File",
    .release_phase = RESOURCE_RELEASE_AFTER_LOCKS,
    .release_priority = RELEASE_PRIO_FILES,
    .ReleaseResource = ResOwnerReleaseFile,
    .DebugPrint = ResOwnerPrintFile
};
 
/* Convenience wrappers over ResourceOwnerRemember/Forget */
static inline void
ResourceOwnerRememberFile(ResourceOwner owner, File file)
{
    ResourceOwnerRemember(owner, Int32GetDatum(file), &file_resowner_desc);
}
static inline void
ResourceOwnerForgetFile(ResourceOwner owner, File file)
{
    ResourceOwnerForget(owner, Int32GetDatum(file), &file_resowner_desc);
}
 
/*
 * pg_fsync --- do fsync with or without writethrough
 */
int
pg_fsync(int fd)
{
#if !defined(WIN32) && defined(USE_ASSERT_CHECKING)
    struct stat st;
 
    /*
     * Some operating system implementations of fsync() have requirements
     * about the file access modes that were used when their file descriptor
     * argument was opened, and these requirements differ depending on whether
     * the file descriptor is for a directory.
     *
     * For any file descriptor that may eventually be handed to fsync(), we
     * should have opened it with access modes that are compatible with
     * fsync() on all supported systems, otherwise the code may not be
     * portable, even if it runs ok on the current system.
     *
     * We assert here that a descriptor for a file was opened with write
     * permissions (i.e., not O_RDONLY) and for a directory without write
     * permissions (O_RDONLY).  Notice that the assertion check is made even
     * if fsync() is disabled.
     *
     * If fstat() fails, ignore it and let the follow-up fsync() complain.
     */
    if (fstat(fd, &st) == 0)
    {
        int         desc_flags = fcntl(fd, F_GETFL);
 
        desc_flags &= O_ACCMODE;
 
        if (S_ISDIR(st.st_mode))
            Assert(desc_flags == O_RDONLY);
        else
            Assert(desc_flags != O_RDONLY);
    }
    errno = 0;
#endif
 
    /* #if is to skip the wal_sync_method test if there's no need for it */
#if defined(HAVE_FSYNC_WRITETHROUGH)
    if (wal_sync_method == WAL_SYNC_METHOD_FSYNC_WRITETHROUGH)
        return pg_fsync_writethrough(fd);
    else
#endif
        return pg_fsync_no_writethrough(fd);
}
 
 
/*
 * pg_fsync_no_writethrough --- same as fsync except does nothing if
 *  enableFsync is off
 */
int
pg_fsync_no_writethrough(int fd)
{
    int         rc;
 
    if (!enableFsync)
        return 0;
 
retry:
    rc = fsync(fd);
 
    if (rc == -1 && errno == EINTR)
        goto retry;
 
    return rc;
}
 
/*
 * pg_fsync_writethrough
 */
int
pg_fsync_writethrough(int fd)
{
    if (enableFsync)
    {
#if defined(F_FULLFSYNC)
        return (fcntl(fd, F_FULLFSYNC, 0) == -1) ? -1 : 0;
#else
        errno = ENOSYS;
        return -1;
#endif
    }
    else
        return 0;
}
 
/*
 * pg_fdatasync --- same as fdatasync except does nothing if enableFsync is off
 */
int
pg_fdatasync(int fd)
{
    int         rc;
 
    if (!enableFsync)
        return 0;
 
retry:
    rc = fdatasync(fd);
 
    if (rc == -1 && errno == EINTR)
        goto retry;
 
    return rc;
}
 
/*
 * pg_file_exists -- check that a file exists.
 *
 * This requires an absolute path to the file.  Returns true if the file is
 * not a directory, false otherwise.
 */
bool
pg_file_exists(const char *name)
{
    struct stat st;
 
    Assert(name != NULL);
 
    if (stat(name, &st) == 0)
        return !S_ISDIR(st.st_mode);
    else if (!(errno == ENOENT || errno == ENOTDIR || errno == EACCES))
        ereport(ERROR,
                (errcode_for_file_access(),
                 errmsg("could not access file \"%s\": %m", name)));
 
    return false;
}
 
/*
 * pg_flush_data --- advise OS that the described dirty data should be flushed
 *
 * offset of 0 with nbytes 0 means that the entire file should be flushed
 */
void
pg_flush_data(int fd, pgoff_t offset, pgoff_t nbytes)
{
    /*
     * Right now file flushing is primarily used to avoid making later
     * fsync()/fdatasync() calls have less impact. Thus don't trigger flushes
     * if fsyncs are disabled - that's a decision we might want to make
     * configurable at some point.
     */
    if (!enableFsync)
        return;
 
    /*
     * We compile all alternatives that are supported on the current platform,
     * to find portability problems more easily.
     */
#if defined(HAVE_SYNC_FILE_RANGE)
    {
        int         rc;
        static bool not_implemented_by_kernel = false;
 
        if (not_implemented_by_kernel)
            return;
 
retry:
 
        /*
         * sync_file_range(SYNC_FILE_RANGE_WRITE), currently linux specific,
         * tells the OS that writeback for the specified blocks should be
         * started, but that we don't want to wait for completion.  Note that
         * this call might block if too much dirty data exists in the range.
         * This is the preferable method on OSs supporting it, as it works
         * reliably when available (contrast to msync()) and doesn't flush out
         * clean data (like FADV_DONTNEED).
         */
        rc = sync_file_range(fd, offset, nbytes,
                             SYNC_FILE_RANGE_WRITE);
        if (rc != 0)
        {
            int         elevel;
 
            if (rc == EINTR)
                goto retry;
 
            /*
             * For systems that don't have an implementation of
             * sync_file_range() such as Windows WSL, generate only one
             * warning and then suppress all further attempts by this process.
             */
            if (errno == ENOSYS)
            {
                elevel = WARNING;
                not_implemented_by_kernel = true;
            }
            else
                elevel = data_sync_elevel(WARNING);
 
            ereport(elevel,
                    (errcode_for_file_access(),
                     errmsg("could not flush dirty data: %m")));
        }
 
        return;
    }
#endif
#if !defined(WIN32) && defined(MS_ASYNC)
    {
        void       *p;
        static int  pagesize = 0;
 
        /*
         * On several OSs msync(MS_ASYNC) on a mmap'ed file triggers
         * writeback. On linux it only does so if MS_SYNC is specified, but
         * then it does the writeback synchronously. Luckily all common linux
         * systems have sync_file_range().  This is preferable over
         * FADV_DONTNEED because it doesn't flush out clean data.
         *
         * We map the file (mmap()), tell the kernel to sync back the contents
         * (msync()), and then remove the mapping again (munmap()).
         */
 
        /* mmap() needs actual length if we want to map whole file */
        if (offset == 0 && nbytes == 0)
        {
            nbytes = lseek(fd, 0, SEEK_END);
            if (nbytes < 0)
            {
                ereport(WARNING,
                        (errcode_for_file_access(),
                         errmsg("could not determine dirty data size: %m")));
                return;
            }
        }
 
        /*
         * Some platforms reject partial-page mmap() attempts.  To deal with
         * that, just truncate the request to a page boundary.  If any extra
         * bytes don't get flushed, well, it's only a hint anyway.
         */
 
        /* fetch pagesize only once */
        if (pagesize == 0)
            pagesize = sysconf(_SC_PAGESIZE);
 
        /* align length to pagesize, dropping any fractional page */
        if (pagesize > 0)
            nbytes = (nbytes / pagesize) * pagesize;
 
        /* fractional-page request is a no-op */
        if (nbytes <= 0)
            return;
 
        /*
         * mmap could well fail, particularly on 32-bit platforms where there
         * may simply not be enough address space.  If so, silently fall
         * through to the next implementation.
         */
        if (nbytes <= (pgoff_t) SSIZE_MAX)
            p = mmap(NULL, nbytes, PROT_READ, MAP_SHARED, fd, offset);
        else
            p = MAP_FAILED;
 
        if (p != MAP_FAILED)
        {
            int         rc;
 
            rc = msync(p, (size_t) nbytes, MS_ASYNC);
            if (rc != 0)
            {
                ereport(data_sync_elevel(WARNING),
                        (errcode_for_file_access(),
                         errmsg("could not flush dirty data: %m")));
                /* NB: need to fall through to munmap()! */
            }
 
            rc = munmap(p, (size_t) nbytes);
            if (rc != 0)
            {
                /* FATAL error because mapping would remain */
                ereport(FATAL,
                        (errcode_for_file_access(),
                         errmsg("could not munmap() while flushing data: %m")));
            }
 
            return;
        }
    }
#endif
#if defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_DONTNEED)
    {
        int         rc;
 
        /*
         * Signal the kernel that the passed in range should not be cached
         * anymore. This has the, desired, side effect of writing out dirty
         * data, and the, undesired, side effect of likely discarding useful
         * clean cached blocks.  For the latter reason this is the least
         * preferable method.
         */
 
        rc = posix_fadvise(fd, offset, nbytes, POSIX_FADV_DONTNEED);
 
        if (rc != 0)
        {
            /* don't error out, this is just a performance optimization */
            ereport(WARNING,
                    (errcode_for_file_access(),
                     errmsg("could not flush dirty data: %m")));
        }
 
        return;
    }
#endif
}
 
/*
 * Truncate an open file to a given length.
 */
static int
pg_ftruncate(int fd, pgoff_t length)
{
    int         ret;
 
retry:
    ret = ftruncate(fd, length);
 
    if (ret == -1 && errno == EINTR)
        goto retry;
 
    return ret;
}
 
/*
 * Truncate a file to a given length by name.
 */
int
pg_truncate(const char *path, pgoff_t length)
{
    int         ret;
#ifdef WIN32
    int         save_errno;
    int         fd;
 
    fd = OpenTransientFile(path, O_RDWR | PG_BINARY);
    if (fd >= 0)
    {
        ret = pg_ftruncate(fd, length);
        save_errno = errno;
        CloseTransientFile(fd);
        errno = save_errno;
    }
    else
        ret = -1;
#else
 
retry:
    ret = truncate(path, length);
 
    if (ret == -1 && errno == EINTR)
        goto retry;
#endif
 
    return ret;
}
 
/*
 * fsync_fname -- fsync a file or directory, handling errors properly
 *
 * Try to fsync a file or directory. When doing the latter, ignore errors that
 * indicate the OS just doesn't allow/require fsyncing directories.
 */
void
fsync_fname(const char *fname, bool isdir)
{
    fsync_fname_ext(fname, isdir, false, data_sync_elevel(ERROR));
}
 
/*
 * durable_rename -- rename(2) wrapper, issuing fsyncs required for durability
 *
 * This routine ensures that, after returning, the effect of renaming file
 * persists in case of a crash. A crash while this routine is running will
 * leave you with either the pre-existing or the moved file in place of the
 * new file; no mixed state or truncated files are possible.
 *
 * It does so by using fsync on the old filename and the possibly existing
 * target filename before the rename, and the target file and directory after.
 *
 * Note that rename() cannot be used across arbitrary directories, as they
 * might not be on the same filesystem. Therefore this routine does not
 * support renaming across directories.
 *
 * Log errors with the caller specified severity.
 *
 * Returns 0 if the operation succeeded, -1 otherwise. Note that errno is not
 * valid upon return.
 */
int
durable_rename(const char *oldfile, const char *newfile, int elevel)
{
    int         fd;
 
    /*
     * First fsync the old and target path (if it exists), to ensure that they
     * are properly persistent on disk. Syncing the target file is not
     * strictly necessary, but it makes it easier to reason about crashes;
     * because it's then guaranteed that either source or target file exists
     * after a crash.
     */
    if (fsync_fname_ext(oldfile, false, false, elevel) != 0)
        return -1;
 
    fd = OpenTransientFile(newfile, PG_BINARY | O_RDWR);
    if (fd < 0)
    {
        if (errno != ENOENT)
        {
            ereport(elevel,
                    (errcode_for_file_access(),
                     errmsg("could not open file \"%s\": %m", newfile)));
            return -1;
        }
    }
    else
    {
        if (pg_fsync(fd) != 0)
        {
            int         save_errno;
 
            /* close file upon error, might not be in transaction context */
            save_errno = errno;
            CloseTransientFile(fd);
            errno = save_errno;
 
            ereport(elevel,
                    (errcode_for_file_access(),
                     errmsg("could not fsync file \"%s\": %m", newfile)));
            return -1;
        }
 
        if (CloseTransientFile(fd) != 0)
        {
            ereport(elevel,
                    (errcode_for_file_access(),
                     errmsg("could not close file \"%s\": %m", newfile)));
            return -1;
        }
    }
 
    /* Time to do the real deal... */
    if (rename(oldfile, newfile) < 0)
    {
        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not rename file \"%s\" to \"%s\": %m",
                        oldfile, newfile)));
        return -1;
    }
 
    /*
     * To guarantee renaming the file is persistent, fsync the file with its
     * new name, and its containing directory.
     */
    if (fsync_fname_ext(newfile, false, false, elevel) != 0)
        return -1;
 
    if (fsync_parent_path(newfile, elevel) != 0)
        return -1;
 
    return 0;
}
 
/*
 * durable_unlink -- remove a file in a durable manner
 *
 * This routine ensures that, after returning, the effect of removing file
 * persists in case of a crash. A crash while this routine is running will
 * leave the system in no mixed state.
 *
 * It does so by using fsync on the parent directory of the file after the
 * actual removal is done.
 *
 * Log errors with the severity specified by caller.
 *
 * Returns 0 if the operation succeeded, -1 otherwise. Note that errno is not
 * valid upon return.
 */
int
durable_unlink(const char *fname, int elevel)
{
    if (unlink(fname) < 0)
    {
        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not remove file \"%s\": %m",
                        fname)));
        return -1;
    }
 
    /*
     * To guarantee that the removal of the file is persistent, fsync its
     * parent directory.
     */
    if (fsync_parent_path(fname, elevel) != 0)
        return -1;
 
    return 0;
}
 
/*
 * InitFileAccess --- initialize this module during backend startup
 *
 * This is called during either normal or standalone backend start.
 * It is *not* called in the postmaster.
 *
 * Note that this does not initialize temporary file access, that is
 * separately initialized via InitTemporaryFileAccess().
 */
void
InitFileAccess(void)
{
    Assert(SizeVfdCache == 0);  /* call me only once */
 
    /* initialize cache header entry */
    VfdCache = (Vfd *) malloc(sizeof(Vfd));
    if (VfdCache == NULL)
        ereport(FATAL,
                (errcode(ERRCODE_OUT_OF_MEMORY),
                 errmsg("out of memory")));
 
    MemSet(&(VfdCache[0]), 0, sizeof(Vfd));
    VfdCache->fd = VFD_CLOSED;
 
    SizeVfdCache = 1;
}
 
/*
 * InitTemporaryFileAccess --- initialize temporary file access during startup
 *
 * This is called during either normal or standalone backend start.
 * It is *not* called in the postmaster.
 *
 * This is separate from InitFileAccess() because temporary file cleanup can
 * cause pgstat reporting. As pgstat is shut down during before_shmem_exit(),
 * our reporting has to happen before that. Low level file access should be
 * available for longer, hence the separate initialization / shutdown of
 * temporary file handling.
 */
void
InitTemporaryFileAccess(void)
{
    Assert(SizeVfdCache != 0);  /* InitFileAccess() needs to have run */
    Assert(!temporary_files_allowed);   /* call me only once */
 
    /*
     * Register before-shmem-exit hook to ensure temp files are dropped while
     * we can still report stats.
     */
    before_shmem_exit(BeforeShmemExit_Files, 0);
 
#ifdef USE_ASSERT_CHECKING
    temporary_files_allowed = true;
#endif
}
 
/*
 * count_usable_fds --- count how many FDs the system will let us open,
 *      and estimate how many are already open.
 *
 * We stop counting if usable_fds reaches max_to_probe.  Note: a small
 * value of max_to_probe might result in an underestimate of already_open;
 * we must fill in any "gaps" in the set of used FDs before the calculation
 * of already_open will give the right answer.  In practice, max_to_probe
 * of a couple of dozen should be enough to ensure good results.
 *
 * We assume stderr (FD 2) is available for dup'ing.  While the calling
 * script could theoretically close that, it would be a really bad idea,
 * since then one risks loss of error messages from, e.g., libc.
 */
static void
count_usable_fds(int max_to_probe, int *usable_fds, int *already_open)
{
    int        *fd;
    int         size;
    int         used = 0;
    int         highestfd = 0;
    int         j;
 
#ifdef HAVE_GETRLIMIT
    struct rlimit rlim;
    int         getrlimit_status;
#endif
 
    size = 1024;
    fd = (int *) palloc(size * sizeof(int));
 
#ifdef HAVE_GETRLIMIT
    getrlimit_status = getrlimit(RLIMIT_NOFILE, &rlim);
    if (getrlimit_status != 0)
        ereport(WARNING, (errmsg("getrlimit failed: %m")));
#endif                          /* HAVE_GETRLIMIT */
 
    /* dup until failure or probe limit reached */
    for (;;)
    {
        int         thisfd;
 
#ifdef HAVE_GETRLIMIT
 
        /*
         * don't go beyond RLIMIT_NOFILE; causes irritating kernel logs on
         * some platforms
         */
        if (getrlimit_status == 0 && highestfd >= rlim.rlim_cur - 1)
            break;
#endif
 
        thisfd = dup(2);
        if (thisfd < 0)
        {
            /* Expect EMFILE or ENFILE, else it's fishy */
            if (errno != EMFILE && errno != ENFILE)
                elog(WARNING, "duplicating stderr file descriptor failed after %d successes: %m", used);
            break;
        }
 
        if (used >= size)
        {
            size *= 2;
            fd = (int *) repalloc(fd, size * sizeof(int));
        }
        fd[used++] = thisfd;
 
        if (highestfd < thisfd)
            highestfd = thisfd;
 
        if (used >= max_to_probe)
            break;
    }
 
    /* release the files we opened */
    for (j = 0; j < used; j++)
        close(fd[j]);
 
    pfree(fd);
 
    /*
     * Return results.  usable_fds is just the number of successful dups. We
     * assume that the system limit is highestfd+1 (remember 0 is a legal FD
     * number) and so already_open is highestfd+1 - usable_fds.
     */
    *usable_fds = used;
    *already_open = highestfd + 1 - used;
}
 
/*
 * set_max_safe_fds
 *      Determine number of file descriptors that fd.c is allowed to use
 */
void
set_max_safe_fds(void)
{
    int         usable_fds;
    int         already_open;
 
    /*----------
     * We want to set max_safe_fds to
     *          MIN(usable_fds, max_files_per_process)
     * less the slop factor for files that are opened without consulting
     * fd.c.  This ensures that we won't allow to open more than
     * max_files_per_process, or the experimentally-determined EMFILE limit,
     * additional files.
     *----------
     */
    count_usable_fds(max_files_per_process,
                     &usable_fds, &already_open);
 
    max_safe_fds = Min(usable_fds, max_files_per_process);
 
    /*
     * Take off the FDs reserved for system() etc.
     */
    max_safe_fds -= NUM_RESERVED_FDS;
 
    /*
     * Make sure we still have enough to get by.
     */
    if (max_safe_fds < FD_MINFREE)
        ereport(FATAL,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("insufficient file descriptors available to start server process"),
                 errdetail("System allows %d, server needs at least %d, %d files are already open.",
                           max_safe_fds + NUM_RESERVED_FDS,
                           FD_MINFREE + NUM_RESERVED_FDS,
                           already_open)));
 
    elog(DEBUG2, "max_safe_fds = %d, usable_fds = %d, already_open = %d",
         max_safe_fds, usable_fds, already_open);
}
 
/*
 * Open a file with BasicOpenFilePerm() and pass default file mode for the
 * fileMode parameter.
 */
int
BasicOpenFile(const char *fileName, int fileFlags)
{
    return BasicOpenFilePerm(fileName, fileFlags, pg_file_create_mode);
}
 
/*
 * BasicOpenFilePerm --- same as open(2) except can free other FDs if needed
 *
 * This is exported for use by places that really want a plain kernel FD,
 * but need to be proof against running out of FDs.  Once an FD has been
 * successfully returned, it is the caller's responsibility to ensure that
 * it will not be leaked on ereport()!  Most users should *not* call this
 * routine directly, but instead use the VFD abstraction level, which
 * provides protection against descriptor leaks as well as management of
 * files that need to be open for more than a short period of time.
 *
 * Ideally this should be the *only* direct call of open() in the backend.
 * In practice, the postmaster calls open() directly, and there are some
 * direct open() calls done early in backend startup.  Those are OK since
 * this module wouldn't have any open files to close at that point anyway.
 */
int
BasicOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode)
{
    int         fd;
 
tryAgain:
#ifdef PG_O_DIRECT_USE_F_NOCACHE
    fd = open(fileName, fileFlags & ~PG_O_DIRECT, fileMode);
#else
    fd = open(fileName, fileFlags, fileMode);
#endif
 
    if (fd >= 0)
    {
#ifdef PG_O_DIRECT_USE_F_NOCACHE
        if (fileFlags & PG_O_DIRECT)
        {
            if (fcntl(fd, F_NOCACHE, 1) < 0)
            {
                int         save_errno = errno;
 
                close(fd);
                errno = save_errno;
                return -1;
            }
        }
#endif
 
        return fd;              /* success! */
    }
 
    if (errno == EMFILE || errno == ENFILE)
    {
        int         save_errno = errno;
 
        ereport(LOG,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("out of file descriptors: %m; release and retry")));
        errno = 0;
        if (ReleaseLruFile())
            goto tryAgain;
        errno = save_errno;
    }
 
    return -1;                  /* failure */
}
 
/*
 * AcquireExternalFD - attempt to reserve an external file descriptor
 *
 * This should be used by callers that need to hold a file descriptor open
 * over more than a short interval, but cannot use any of the other facilities
 * provided by this module.
 *
 * The difference between this and the underlying ReserveExternalFD function
 * is that this will report failure (by setting errno and returning false)
 * if "too many" external FDs are already reserved.  This should be used in
 * any code where the total number of FDs to be reserved is not predictable
 * and small.
 */
bool
AcquireExternalFD(void)
{
    /*
     * We don't want more than max_safe_fds / 3 FDs to be consumed for
     * "external" FDs.
     */
    if (numExternalFDs < max_safe_fds / 3)
    {
        ReserveExternalFD();
        return true;
    }
    errno = EMFILE;
    return false;
}
 
/*
 * ReserveExternalFD - report external consumption of a file descriptor
 *
 * This should be used by callers that need to hold a file descriptor open
 * over more than a short interval, but cannot use any of the other facilities
 * provided by this module.  This just tracks the use of the FD and closes
 * VFDs if needed to ensure we keep NUM_RESERVED_FDS FDs available.
 *
 * Call this directly only in code where failure to reserve the FD would be
 * fatal; for example, the WAL-writing code does so, since the alternative is
 * session failure.  Also, it's very unwise to do so in code that could
 * consume more than one FD per process.
 *
 * Note: as long as everybody plays nice so that NUM_RESERVED_FDS FDs remain
 * available, it doesn't matter too much whether this is called before or
 * after actually opening the FD; but doing so beforehand reduces the risk of
 * an EMFILE failure if not everybody played nice.  In any case, it's solely
 * caller's responsibility to keep the external-FD count in sync with reality.
 */
void
ReserveExternalFD(void)
{
    /*
     * Release VFDs if needed to stay safe.  Because we do this before
     * incrementing numExternalFDs, the final state will be as desired, i.e.,
     * nfile + numAllocatedDescs + numExternalFDs <= max_safe_fds.
     */
    ReleaseLruFiles();
 
    numExternalFDs++;
}
 
/*
 * ReleaseExternalFD - report release of an external file descriptor
 *
 * This is guaranteed not to change errno, so it can be used in failure paths.
 */
void
ReleaseExternalFD(void)
{
    Assert(numExternalFDs > 0);
    numExternalFDs--;
}
 
 
#if defined(FDDEBUG)
 
static void
_dump_lru(void)
{
    int         mru = VfdCache[0].lruLessRecently;
    Vfd        *vfdP = &VfdCache[mru];
    char        buf[2048];
 
    snprintf(buf, sizeof(buf), "LRU: MOST %d ", mru);
    while (mru != 0)
    {
        mru = vfdP->lruLessRecently;
        vfdP = &VfdCache[mru];
        snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "%d ", mru);
    }
    snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "LEAST");
    elog(LOG, "%s", buf);
}
#endif                          /* FDDEBUG */
 
static void
Delete(File file)
{
    Vfd        *vfdP;
 
    Assert(file != 0);
 
    DO_DB(elog(LOG, "Delete %d (%s)",
               file, VfdCache[file].fileName));
    DO_DB(_dump_lru());
 
    vfdP = &VfdCache[file];
 
    VfdCache[vfdP->lruLessRecently].lruMoreRecently = vfdP->lruMoreRecently;
    VfdCache[vfdP->lruMoreRecently].lruLessRecently = vfdP->lruLessRecently;
 
    DO_DB(_dump_lru());
}
 
static void
LruDelete(File file)
{
    Vfd        *vfdP;
 
    Assert(file != 0);
 
    DO_DB(elog(LOG, "LruDelete %d (%s)",
               file, VfdCache[file].fileName));
 
    vfdP = &VfdCache[file];
 
    pgaio_closing_fd(vfdP->fd);
 
    /*
     * Close the file.  We aren't expecting this to fail; if it does, better
     * to leak the FD than to mess up our internal state.
     */
    if (close(vfdP->fd) != 0)
        elog(vfdP->fdstate & FD_TEMP_FILE_LIMIT ? LOG : data_sync_elevel(LOG),
             "could not close file \"%s\": %m", vfdP->fileName);
    vfdP->fd = VFD_CLOSED;
    --nfile;
 
    /* delete the vfd record from the LRU ring */
    Delete(file);
}
 
static void
Insert(File file)
{
    Vfd        *vfdP;
 
    Assert(file != 0);
 
    DO_DB(elog(LOG, "Insert %d (%s)",
               file, VfdCache[file].fileName));
    DO_DB(_dump_lru());
 
    vfdP = &VfdCache[file];
 
    vfdP->lruMoreRecently = 0;
    vfdP->lruLessRecently = VfdCache[0].lruLessRecently;
    VfdCache[0].lruLessRecently = file;
    VfdCache[vfdP->lruLessRecently].lruMoreRecently = file;
 
    DO_DB(_dump_lru());
}
 
/* returns 0 on success, -1 on re-open failure (with errno set) */
static int
LruInsert(File file)
{
    Vfd        *vfdP;
 
    Assert(file != 0);
 
    DO_DB(elog(LOG, "LruInsert %d (%s)",
               file, VfdCache[file].fileName));
 
    vfdP = &VfdCache[file];
 
    if (FileIsNotOpen(file))
    {
        /* Close excess kernel FDs. */
        ReleaseLruFiles();
 
        /*
         * The open could still fail for lack of file descriptors, eg due to
         * overall system file table being full.  So, be prepared to release
         * another FD if necessary...
         */
        vfdP->fd = BasicOpenFilePerm(vfdP->fileName, vfdP->fileFlags,
                                     vfdP->fileMode);
        if (vfdP->fd < 0)
        {
            DO_DB(elog(LOG, "re-open failed: %m"));
            return -1;
        }
        else
        {
            ++nfile;
        }
    }
 
    /*
     * put it at the head of the Lru ring
     */
 
    Insert(file);
 
    return 0;
}
 
/*
 * Release one kernel FD by closing the least-recently-used VFD.
 */
static bool
ReleaseLruFile(void)
{
    DO_DB(elog(LOG, "ReleaseLruFile. Opened %d", nfile));
 
    if (nfile > 0)
    {
        /*
         * There are opened files and so there should be at least one used vfd
         * in the ring.
         */
        Assert(VfdCache[0].lruMoreRecently != 0);
        LruDelete(VfdCache[0].lruMoreRecently);
        return true;            /* freed a file */
    }
    return false;               /* no files available to free */
}
 
/*
 * Release kernel FDs as needed to get under the max_safe_fds limit.
 * After calling this, it's OK to try to open another file.
 */
static void
ReleaseLruFiles(void)
{
    while (nfile + numAllocatedDescs + numExternalFDs >= max_safe_fds)
    {
        if (!ReleaseLruFile())
            break;
    }
}
 
static File
AllocateVfd(void)
{
    Index       i;
    File        file;
 
    DO_DB(elog(LOG, "AllocateVfd. Size %zu", SizeVfdCache));
 
    Assert(SizeVfdCache > 0);   /* InitFileAccess not called? */
 
    if (VfdCache[0].nextFree == 0)
    {
        /*
         * The free list is empty so it is time to increase the size of the
         * array.  We choose to double it each time this happens. However,
         * there's not much point in starting *real* small.
         */
        Size        newCacheSize = SizeVfdCache * 2;
        Vfd        *newVfdCache;
 
        if (newCacheSize < 32)
            newCacheSize = 32;
 
        /*
         * Be careful not to clobber VfdCache ptr if realloc fails.
         */
        newVfdCache = (Vfd *) realloc(VfdCache, sizeof(Vfd) * newCacheSize);
        if (newVfdCache == NULL)
            ereport(ERROR,
                    (errcode(ERRCODE_OUT_OF_MEMORY),
                     errmsg("out of memory")));
        VfdCache = newVfdCache;
 
        /*
         * Initialize the new entries and link them into the free list.
         */
        for (i = SizeVfdCache; i < newCacheSize; i++)
        {
            MemSet(&(VfdCache[i]), 0, sizeof(Vfd));
            VfdCache[i].nextFree = i + 1;
            VfdCache[i].fd = VFD_CLOSED;
        }
        VfdCache[newCacheSize - 1].nextFree = 0;
        VfdCache[0].nextFree = SizeVfdCache;
 
        /*
         * Record the new size
         */
        SizeVfdCache = newCacheSize;
    }
 
    file = VfdCache[0].nextFree;
 
    VfdCache[0].nextFree = VfdCache[file].nextFree;
 
    return file;
}
 
static void
FreeVfd(File file)
{
    Vfd        *vfdP = &VfdCache[file];
 
    DO_DB(elog(LOG, "FreeVfd: %d (%s)",
               file, vfdP->fileName ? vfdP->fileName : ""));
 
    if (vfdP->fileName != NULL)
    {
        free(vfdP->fileName);
        vfdP->fileName = NULL;
    }
    vfdP->fdstate = 0x0;
 
    vfdP->nextFree = VfdCache[0].nextFree;
    VfdCache[0].nextFree = file;
}
 
/* returns 0 on success, -1 on re-open failure (with errno set) */
static int
FileAccess(File file)
{
    int         returnValue;
 
    DO_DB(elog(LOG, "FileAccess %d (%s)",
               file, VfdCache[file].fileName));
 
    /*
     * Is the file open?  If not, open it and put it at the head of the LRU
     * ring (possibly closing the least recently used file to get an FD).
     */
 
    if (FileIsNotOpen(file))
    {
        returnValue = LruInsert(file);
        if (returnValue != 0)
            return returnValue;
    }
    else if (VfdCache[0].lruLessRecently != file)
    {
        /*
         * We now know that the file is open and that it is not the last one
         * accessed, so we need to move it to the head of the Lru ring.
         */
 
        Delete(file);
        Insert(file);
    }
 
    return 0;
}
 
/*
 * Called whenever a temporary file is deleted to report its size.
 */
static void
ReportTemporaryFileUsage(const char *path, pgoff_t size)
{
    pgstat_report_tempfile(size);
 
    if (log_temp_files >= 0)
    {
        if ((size / 1024) >= log_temp_files)
            ereport(LOG,
                    (errmsg("temporary file: path \"%s\", size %lu",
                            path, (unsigned long) size)));
    }
}
 
/*
 * Called to register a temporary file for automatic close.
 * ResourceOwnerEnlarge(CurrentResourceOwner) must have been called
 * before the file was opened.
 */
static void
RegisterTemporaryFile(File file)
{
    ResourceOwnerRememberFile(CurrentResourceOwner, file);
    VfdCache[file].resowner = CurrentResourceOwner;
 
    /* Backup mechanism for closing at end of xact. */
    VfdCache[file].fdstate |= FD_CLOSE_AT_EOXACT;
    have_xact_temporary_files = true;
}
 
/*
 *  Called when we get a shared invalidation message on some relation.
 */
#ifdef NOT_USED
void
FileInvalidate(File file)
{
    Assert(FileIsValid(file));
    if (!FileIsNotOpen(file))
        LruDelete(file);
}
#endif
 
/*
 * Open a file with PathNameOpenFilePerm() and pass default file mode for the
 * fileMode parameter.
 */
File
PathNameOpenFile(const char *fileName, int fileFlags)
{
    return PathNameOpenFilePerm(fileName, fileFlags, pg_file_create_mode);
}
 
/*
 * open a file in an arbitrary directory
 *
 * NB: if the passed pathname is relative (which it usually is),
 * it will be interpreted relative to the process' working directory
 * (which should always be $PGDATA when this code is running).
 */
File
PathNameOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode)
{
    char       *fnamecopy;
    File        file;
    Vfd        *vfdP;
 
    DO_DB(elog(LOG, "PathNameOpenFilePerm: %s %x %o",
               fileName, fileFlags, fileMode));
 
    /*
     * We need a malloc'd copy of the file name; fail cleanly if no room.
     */
    fnamecopy = strdup(fileName);
    if (fnamecopy == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_OUT_OF_MEMORY),
                 errmsg("out of memory")));
 
    file = AllocateVfd();
    vfdP = &VfdCache[file];
 
    /* Close excess kernel FDs. */
    ReleaseLruFiles();
 
    /*
     * Descriptors managed by VFDs are implicitly marked O_CLOEXEC.  The
     * client shouldn't be expected to know which kernel descriptors are
     * currently open, so it wouldn't make sense for them to be inherited by
     * executed subprograms.
     */
    fileFlags |= O_CLOEXEC;
 
    vfdP->fd = BasicOpenFilePerm(fileName, fileFlags, fileMode);
 
    if (vfdP->fd < 0)
    {
        int         save_errno = errno;
 
        FreeVfd(file);
        free(fnamecopy);
        errno = save_errno;
        return -1;
    }
    ++nfile;
    DO_DB(elog(LOG, "PathNameOpenFile: success %d",
               vfdP->fd));
 
    vfdP->fileName = fnamecopy;
    /* Saved flags are adjusted to be OK for re-opening file */
    vfdP->fileFlags = fileFlags & ~(O_CREAT | O_TRUNC | O_EXCL);
    vfdP->fileMode = fileMode;
    vfdP->fileSize = 0;
    vfdP->fdstate = 0x0;
    vfdP->resowner = NULL;
 
    Insert(file);
 
    return file;
}
 
/*
 * Create directory 'directory'.  If necessary, create 'basedir', which must
 * be the directory above it.  This is designed for creating the top-level
 * temporary directory on demand before creating a directory underneath it.
 * Do nothing if the directory already exists.
 *
 * Directories created within the top-level temporary directory should begin
 * with PG_TEMP_FILE_PREFIX, so that they can be identified as temporary and
 * deleted at startup by RemovePgTempFiles().  Further subdirectories below
 * that do not need any particular prefix.
*/
void
PathNameCreateTemporaryDir(const char *basedir, const char *directory)
{
    if (MakePGDirectory(directory) < 0)
    {
        if (errno == EEXIST)
            return;
 
        /*
         * Failed.  Try to create basedir first in case it's missing. Tolerate
         * EEXIST to close a race against another process following the same
         * algorithm.
         */
        if (MakePGDirectory(basedir) < 0 && errno != EEXIST)
            ereport(ERROR,
                    (errcode_for_file_access(),
                     errmsg("cannot create temporary directory \"%s\": %m",
                            basedir)));
 
        /* Try again. */
        if (MakePGDirectory(directory) < 0 && errno != EEXIST)
            ereport(ERROR,
                    (errcode_for_file_access(),
                     errmsg("cannot create temporary subdirectory \"%s\": %m",
                            directory)));
    }
}
 
/*
 * Delete a directory and everything in it, if it exists.
 */
void
PathNameDeleteTemporaryDir(const char *dirname)
{
    struct stat statbuf;
 
    /* Silently ignore missing directory. */
    if (stat(dirname, &statbuf) != 0 && errno == ENOENT)
        return;
 
    /*
     * Currently, walkdir doesn't offer a way for our passed in function to
     * maintain state.  Perhaps it should, so that we could tell the caller
     * whether this operation succeeded or failed.  Since this operation is
     * used in a cleanup path, we wouldn't actually behave differently: we'll
     * just log failures.
     */
    walkdir(dirname, unlink_if_exists_fname, false, LOG);
}
 
/*
 * Open a temporary file that will disappear when we close it.
 *
 * This routine takes care of generating an appropriate tempfile name.
 * There's no need to pass in fileFlags or fileMode either, since only
 * one setting makes any sense for a temp file.
 *
 * Unless interXact is true, the file is remembered by CurrentResourceOwner
 * to ensure it's closed and deleted when it's no longer needed, typically at
 * the end-of-transaction. In most cases, you don't want temporary files to
 * outlive the transaction that created them, so this should be false -- but
 * if you need "somewhat" temporary storage, this might be useful. In either
 * case, the file is removed when the File is explicitly closed.
 */
File
OpenTemporaryFile(bool interXact)
{
    File        file = 0;
 
    Assert(temporary_files_allowed);    /* check temp file access is up */
 
    /*
     * Make sure the current resource owner has space for this File before we
     * open it, if we'll be registering it below.
     */
    if (!interXact)
        ResourceOwnerEnlarge(CurrentResourceOwner);
 
    /*
     * If some temp tablespace(s) have been given to us, try to use the next
     * one.  If a given tablespace can't be found, we silently fall back to
     * the database's default tablespace.
     *
     * BUT: if the temp file is slated to outlive the current transaction,
     * force it into the database's default tablespace, so that it will not
     * pose a threat to possible tablespace drop attempts.
     */
    if (numTempTableSpaces > 0 && !interXact)
    {
        Oid         tblspcOid = GetNextTempTableSpace();
 
        if (OidIsValid(tblspcOid))
            file = OpenTemporaryFileInTablespace(tblspcOid, false);
    }
 
    /*
     * If not, or if tablespace is bad, create in database's default
     * tablespace.  MyDatabaseTableSpace should normally be set before we get
     * here, but just in case it isn't, fall back to pg_default tablespace.
     */
    if (file <= 0)
        file = OpenTemporaryFileInTablespace(MyDatabaseTableSpace ?
                                             MyDatabaseTableSpace :
                                             DEFAULTTABLESPACE_OID,
                                             true);
 
    /* Mark it for deletion at close and temporary file size limit */
    VfdCache[file].fdstate |= FD_DELETE_AT_CLOSE | FD_TEMP_FILE_LIMIT;
 
    /* Register it with the current resource owner */
    if (!interXact)
        RegisterTemporaryFile(file);
 
    return file;
}
 
/*
 * Return the path of the temp directory in a given tablespace.
 */
void
TempTablespacePath(char *path, Oid tablespace)
{
    /*
     * Identify the tempfile directory for this tablespace.
     *
     * If someone tries to specify pg_global, use pg_default instead.
     */
    if (tablespace == InvalidOid ||
        tablespace == DEFAULTTABLESPACE_OID ||
        tablespace == GLOBALTABLESPACE_OID)
        snprintf(path, MAXPGPATH, "base/%s", PG_TEMP_FILES_DIR);
    else
    {
        /* All other tablespaces are accessed via symlinks */
        snprintf(path, MAXPGPATH, "%s/%u/%s/%s",
                 PG_TBLSPC_DIR, tablespace, TABLESPACE_VERSION_DIRECTORY,
                 PG_TEMP_FILES_DIR);
    }
}
 
/*
 * Open a temporary file in a specific tablespace.
 * Subroutine for OpenTemporaryFile, which see for details.
 */
static File
OpenTemporaryFileInTablespace(Oid tblspcOid, bool rejectError)
{
    char        tempdirpath[MAXPGPATH];
    char        tempfilepath[MAXPGPATH];
    File        file;
 
    TempTablespacePath(tempdirpath, tblspcOid);
 
    /*
     * Generate a tempfile name that should be unique within the current
     * database instance.
     */
    snprintf(tempfilepath, sizeof(tempfilepath), "%s/%s%d.%ld",
             tempdirpath, PG_TEMP_FILE_PREFIX, MyProcPid, tempFileCounter++);
 
    /*
     * Open the file.  Note: we don't use O_EXCL, in case there is an orphaned
     * temp file that can be reused.
     */
    file = PathNameOpenFile(tempfilepath,
                            O_RDWR | O_CREAT | O_TRUNC | PG_BINARY);
    if (file <= 0)
    {
        /*
         * We might need to create the tablespace's tempfile directory, if no
         * one has yet done so.
         *
         * Don't check for an error from MakePGDirectory; it could fail if
         * someone else just did the same thing.  If it doesn't work then
         * we'll bomb out on the second create attempt, instead.
         */
        (void) MakePGDirectory(tempdirpath);
 
        file = PathNameOpenFile(tempfilepath,
                                O_RDWR | O_CREAT | O_TRUNC | PG_BINARY);
        if (file <= 0 && rejectError)
            elog(ERROR, "could not create temporary file \"%s\": %m",
                 tempfilepath);
    }
 
    return file;
}
 
 
/*
 * Create a new file.  The directory containing it must already exist.  Files
 * created this way are subject to temp_file_limit and are automatically
 * closed at end of transaction, but are not automatically deleted on close
 * because they are intended to be shared between cooperating backends.
 *
 * If the file is inside the top-level temporary directory, its name should
 * begin with PG_TEMP_FILE_PREFIX so that it can be identified as temporary
 * and deleted at startup by RemovePgTempFiles().  Alternatively, it can be
 * inside a directory created with PathNameCreateTemporaryDir(), in which case
 * the prefix isn't needed.
 */
File
PathNameCreateTemporaryFile(const char *path, bool error_on_failure)
{
    File        file;
 
    Assert(temporary_files_allowed);    /* check temp file access is up */
 
    ResourceOwnerEnlarge(CurrentResourceOwner);
 
    /*
     * Open the file.  Note: we don't use O_EXCL, in case there is an orphaned
     * temp file that can be reused.
     */
    file = PathNameOpenFile(path, O_RDWR | O_CREAT | O_TRUNC | PG_BINARY);
    if (file <= 0)
    {
        if (error_on_failure)
            ereport(ERROR,
                    (errcode_for_file_access(),
                     errmsg("could not create temporary file \"%s\": %m",
                            path)));
        else
            return file;
    }
 
    /* Mark it for temp_file_limit accounting. */
    VfdCache[file].fdstate |= FD_TEMP_FILE_LIMIT;
 
    /* Register it for automatic close. */
    RegisterTemporaryFile(file);
 
    return file;
}
 
/*
 * Open a file that was created with PathNameCreateTemporaryFile, possibly in
 * another backend.  Files opened this way don't count against the
 * temp_file_limit of the caller, are automatically closed at the end of the
 * transaction but are not deleted on close.
 */
File
PathNameOpenTemporaryFile(const char *path, int mode)
{
    File        file;
 
    Assert(temporary_files_allowed);    /* check temp file access is up */
 
    ResourceOwnerEnlarge(CurrentResourceOwner);
 
    file = PathNameOpenFile(path, mode | PG_BINARY);
 
    /* If no such file, then we don't raise an error. */
    if (file <= 0 && errno != ENOENT)
        ereport(ERROR,
                (errcode_for_file_access(),
                 errmsg("could not open temporary file \"%s\": %m",
                        path)));
 
    if (file > 0)
    {
        /* Register it for automatic close. */
        RegisterTemporaryFile(file);
    }
 
    return file;
}
 
/*
 * Delete a file by pathname.  Return true if the file existed, false if
 * didn't.
 */
bool
PathNameDeleteTemporaryFile(const char *path, bool error_on_failure)
{
    struct stat filestats;
    int         stat_errno;
 
    /* Get the final size for pgstat reporting. */
    if (stat(path, &filestats) != 0)
        stat_errno = errno;
    else
        stat_errno = 0;
 
    /*
     * Unlike FileClose's automatic file deletion code, we tolerate
     * non-existence to support BufFileDeleteFileSet which doesn't know how
     * many segments it has to delete until it runs out.
     */
    if (stat_errno == ENOENT)
        return false;
 
    if (unlink(path) < 0)
    {
        if (errno != ENOENT)
            ereport(error_on_failure ? ERROR : LOG,
                    (errcode_for_file_access(),
                     errmsg("could not unlink temporary file \"%s\": %m",
                            path)));
        return false;
    }
 
    if (stat_errno == 0)
        ReportTemporaryFileUsage(path, filestats.st_size);
    else
    {
        errno = stat_errno;
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not stat file \"%s\": %m", path)));
    }
 
    return true;
}
 
/*
 * close a file when done with it
 */
void
FileClose(File file)
{
    Vfd        *vfdP;
 
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileClose: %d (%s)",
               file, VfdCache[file].fileName));
 
    vfdP = &VfdCache[file];
 
    if (!FileIsNotOpen(file))
    {
        pgaio_closing_fd(vfdP->fd);
 
        /* close the file */
        if (close(vfdP->fd) != 0)
        {
            /*
             * We may need to panic on failure to close non-temporary files;
             * see LruDelete.
             */
            elog(vfdP->fdstate & FD_TEMP_FILE_LIMIT ? LOG : data_sync_elevel(LOG),
                 "could not close file \"%s\": %m", vfdP->fileName);
        }
 
        --nfile;
        vfdP->fd = VFD_CLOSED;
 
        /* remove the file from the lru ring */
        Delete(file);
    }
 
    if (vfdP->fdstate & FD_TEMP_FILE_LIMIT)
    {
        /* Subtract its size from current usage (do first in case of error) */
        temporary_files_size -= vfdP->fileSize;
        vfdP->fileSize = 0;
    }
 
    /*
     * Delete the file if it was temporary, and make a log entry if wanted
     */
    if (vfdP->fdstate & FD_DELETE_AT_CLOSE)
    {
        struct stat filestats;
        int         stat_errno;
 
        /*
         * If we get an error, as could happen within the ereport/elog calls,
         * we'll come right back here during transaction abort.  Reset the
         * flag to ensure that we can't get into an infinite loop.  This code
         * is arranged to ensure that the worst-case consequence is failing to
         * emit log message(s), not failing to attempt the unlink.
         */
        vfdP->fdstate &= ~FD_DELETE_AT_CLOSE;
 
 
        /* first try the stat() */
        if (stat(vfdP->fileName, &filestats))
            stat_errno = errno;
        else
            stat_errno = 0;
 
        /* in any case do the unlink */
        if (unlink(vfdP->fileName))
            ereport(LOG,
                    (errcode_for_file_access(),
                     errmsg("could not delete file \"%s\": %m", vfdP->fileName)));
 
        /* and last report the stat results */
        if (stat_errno == 0)
            ReportTemporaryFileUsage(vfdP->fileName, filestats.st_size);
        else
        {
            errno = stat_errno;
            ereport(LOG,
                    (errcode_for_file_access(),
                     errmsg("could not stat file \"%s\": %m", vfdP->fileName)));
        }
    }
 
    /* Unregister it from the resource owner */
    if (vfdP->resowner)
        ResourceOwnerForgetFile(vfdP->resowner, file);
 
    /*
     * Return the Vfd slot to the free list
     */
    FreeVfd(file);
}
 
/*
 * FilePrefetch - initiate asynchronous read of a given range of the file.
 *
 * Returns 0 on success, otherwise an errno error code (like posix_fadvise()).
 *
 * posix_fadvise() is the simplest standardized interface that accomplishes
 * this.
 */
int
FilePrefetch(File file, pgoff_t offset, pgoff_t amount, uint32 wait_event_info)
{
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FilePrefetch: %d (%s) " INT64_FORMAT " " INT64_FORMAT,
               file, VfdCache[file].fileName,
               (int64) offset, (int64) amount));
 
#if defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_WILLNEED)
    {
        int         returnCode;
 
        returnCode = FileAccess(file);
        if (returnCode < 0)
            return returnCode;
 
retry:
        pgstat_report_wait_start(wait_event_info);
        returnCode = posix_fadvise(VfdCache[file].fd, offset, amount,
                                   POSIX_FADV_WILLNEED);
        pgstat_report_wait_end();
 
        if (returnCode == EINTR)
            goto retry;
 
        return returnCode;
    }
#elif defined(__darwin__)
    {
        struct radvisory
        {
            off_t       ra_offset;  /* offset into the file */
            int         ra_count;   /* size of the read     */
        }           ra;
        int         returnCode;
 
        returnCode = FileAccess(file);
        if (returnCode < 0)
            return returnCode;
 
        ra.ra_offset = offset;
        ra.ra_count = amount;
        pgstat_report_wait_start(wait_event_info);
        returnCode = fcntl(VfdCache[file].fd, F_RDADVISE, &ra);
        pgstat_report_wait_end();
        if (returnCode != -1)
            return 0;
        else
            return errno;
    }
#else
    return 0;
#endif
}
 
void
FileWriteback(File file, pgoff_t offset, pgoff_t nbytes, uint32 wait_event_info)
{
    int         returnCode;
 
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileWriteback: %d (%s) " INT64_FORMAT " " INT64_FORMAT,
               file, VfdCache[file].fileName,
               (int64) offset, (int64) nbytes));
 
    if (nbytes <= 0)
        return;
 
    if (VfdCache[file].fileFlags & PG_O_DIRECT)
        return;
 
    returnCode = FileAccess(file);
    if (returnCode < 0)
        return;
 
    pgstat_report_wait_start(wait_event_info);
    pg_flush_data(VfdCache[file].fd, offset, nbytes);
    pgstat_report_wait_end();
}
 
ssize_t
FileReadV(File file, const struct iovec *iov, int iovcnt, pgoff_t offset,
          uint32 wait_event_info)
{
    ssize_t     returnCode;
    Vfd        *vfdP;
 
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileReadV: %d (%s) " INT64_FORMAT " %d",
               file, VfdCache[file].fileName,
               (int64) offset,
               iovcnt));
 
    returnCode = FileAccess(file);
    if (returnCode < 0)
        return returnCode;
 
    vfdP = &VfdCache[file];
 
retry:
    pgstat_report_wait_start(wait_event_info);
    returnCode = pg_preadv(vfdP->fd, iov, iovcnt, offset);
    pgstat_report_wait_end();
 
    if (returnCode < 0)
    {
        /*
         * Windows may run out of kernel buffers and return "Insufficient
         * system resources" error.  Wait a bit and retry to solve it.
         *
         * It is rumored that EINTR is also possible on some Unix filesystems,
         * in which case immediate retry is indicated.
         */
#ifdef WIN32
        DWORD       error = GetLastError();
 
        switch (error)
        {
            case ERROR_NO_SYSTEM_RESOURCES:
                pg_usleep(1000L);
                errno = EINTR;
                break;
            default:
                _dosmaperr(error);
                break;
        }
#endif
        /* OK to retry if interrupted */
        if (errno == EINTR)
            goto retry;
    }
 
    return returnCode;
}
 
int
FileStartReadV(PgAioHandle *ioh, File file,
               int iovcnt, pgoff_t offset,
               uint32 wait_event_info)
{
    int         returnCode;
    Vfd        *vfdP;
 
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileStartReadV: %d (%s) " INT64_FORMAT " %d",
               file, VfdCache[file].fileName,
               (int64) offset,
               iovcnt));
 
    returnCode = FileAccess(file);
    if (returnCode < 0)
        return returnCode;
 
    vfdP = &VfdCache[file];
 
    pgaio_io_start_readv(ioh, vfdP->fd, iovcnt, offset);
 
    return 0;
}
 
ssize_t
FileWriteV(File file, const struct iovec *iov, int iovcnt, pgoff_t offset,
           uint32 wait_event_info)
{
    ssize_t     returnCode;
    Vfd        *vfdP;
 
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileWriteV: %d (%s) " INT64_FORMAT " %d",
               file, VfdCache[file].fileName,
               (int64) offset,
               iovcnt));
 
    returnCode = FileAccess(file);
    if (returnCode < 0)
        return returnCode;
 
    vfdP = &VfdCache[file];
 
    /*
     * If enforcing temp_file_limit and it's a temp file, check to see if the
     * write would overrun temp_file_limit, and throw error if so.  Note: it's
     * really a modularity violation to throw error here; we should set errno
     * and return -1.  However, there's no way to report a suitable error
     * message if we do that.  All current callers would just throw error
     * immediately anyway, so this is safe at present.
     */
    if (temp_file_limit >= 0 && (vfdP->fdstate & FD_TEMP_FILE_LIMIT))
    {
        pgoff_t     past_write = offset;
 
        for (int i = 0; i < iovcnt; ++i)
            past_write += iov[i].iov_len;
 
        if (past_write > vfdP->fileSize)
        {
            uint64      newTotal = temporary_files_size;
 
            newTotal += past_write - vfdP->fileSize;
            if (newTotal > (uint64) temp_file_limit * (uint64) 1024)
                ereport(ERROR,
                        (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED),
                         errmsg("temporary file size exceeds \"temp_file_limit\" (%dkB)",
                                temp_file_limit)));
        }
    }
 
retry:
    pgstat_report_wait_start(wait_event_info);
    returnCode = pg_pwritev(vfdP->fd, iov, iovcnt, offset);
    pgstat_report_wait_end();
 
    if (returnCode >= 0)
    {
        /*
         * Some callers expect short writes to set errno, and traditionally we
         * have assumed that they imply disk space shortage.  We don't want to
         * waste CPU cycles adding up the total size here, so we'll just set
         * it for all successful writes in case such a caller determines that
         * the write was short and ereports "%m".
         */
        errno = ENOSPC;
 
        /*
         * Maintain fileSize and temporary_files_size if it's a temp file.
         */
        if (vfdP->fdstate & FD_TEMP_FILE_LIMIT)
        {
            pgoff_t     past_write = offset + returnCode;
 
            if (past_write > vfdP->fileSize)
            {
                temporary_files_size += past_write - vfdP->fileSize;
                vfdP->fileSize = past_write;
            }
        }
    }
    else
    {
        /*
         * See comments in FileReadV()
         */
#ifdef WIN32
        DWORD       error = GetLastError();
 
        switch (error)
        {
            case ERROR_NO_SYSTEM_RESOURCES:
                pg_usleep(1000L);
                errno = EINTR;
                break;
            default:
                _dosmaperr(error);
                break;
        }
#endif
        /* OK to retry if interrupted */
        if (errno == EINTR)
            goto retry;
    }
 
    return returnCode;
}
 
int
FileSync(File file, uint32 wait_event_info)
{
    int         returnCode;
 
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileSync: %d (%s)",
               file, VfdCache[file].fileName));
 
    returnCode = FileAccess(file);
    if (returnCode < 0)
        return returnCode;
 
    pgstat_report_wait_start(wait_event_info);
    returnCode = pg_fsync(VfdCache[file].fd);
    pgstat_report_wait_end();
 
    return returnCode;
}
 
/*
 * Zero a region of the file.
 *
 * Returns 0 on success, -1 otherwise. In the latter case errno is set to the
 * appropriate error.
 */
int
FileZero(File file, pgoff_t offset, pgoff_t amount, uint32 wait_event_info)
{
    int         returnCode;
    ssize_t     written;
 
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileZero: %d (%s) " INT64_FORMAT " " INT64_FORMAT,
               file, VfdCache[file].fileName,
               (int64) offset, (int64) amount));
 
    returnCode = FileAccess(file);
    if (returnCode < 0)
        return returnCode;
 
    pgstat_report_wait_start(wait_event_info);
    written = pg_pwrite_zeros(VfdCache[file].fd, amount, offset);
    pgstat_report_wait_end();
 
    if (written < 0)
        return -1;
    else if (written != amount)
    {
        /* if errno is unset, assume problem is no disk space */
        if (errno == 0)
            errno = ENOSPC;
        return -1;
    }
 
    return 0;
}
 
/*
 * Try to reserve file space with posix_fallocate(). If posix_fallocate() is
 * not implemented on the operating system or fails with EINVAL / EOPNOTSUPP,
 * use FileZero() instead.
 *
 * Note that at least glibc() implements posix_fallocate() in userspace if not
 * implemented by the filesystem. That's not the case for all environments
 * though.
 *
 * Returns 0 on success, -1 otherwise. In the latter case errno is set to the
 * appropriate error.
 */
int
FileFallocate(File file, pgoff_t offset, pgoff_t amount, uint32 wait_event_info)
{
#ifdef HAVE_POSIX_FALLOCATE
    int         returnCode;
 
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileFallocate: %d (%s) " INT64_FORMAT " " INT64_FORMAT,
               file, VfdCache[file].fileName,
               (int64) offset, (int64) amount));
 
    returnCode = FileAccess(file);
    if (returnCode < 0)
        return -1;
 
retry:
    pgstat_report_wait_start(wait_event_info);
    returnCode = posix_fallocate(VfdCache[file].fd, offset, amount);
    pgstat_report_wait_end();
 
    if (returnCode == 0)
        return 0;
    else if (returnCode == EINTR)
        goto retry;
 
    /* for compatibility with %m printing etc */
    errno = returnCode;
 
    /*
     * Return in cases of a "real" failure, if fallocate is not supported,
     * fall through to the FileZero() backed implementation.
     */
    if (returnCode != EINVAL && returnCode != EOPNOTSUPP)
        return -1;
#endif
 
    return FileZero(file, offset, amount, wait_event_info);
}
 
pgoff_t
FileSize(File file)
{
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileSize %d (%s)",
               file, VfdCache[file].fileName));
 
    if (FileIsNotOpen(file))
    {
        if (FileAccess(file) < 0)
            return (pgoff_t) -1;
    }
 
    return lseek(VfdCache[file].fd, 0, SEEK_END);
}
 
int
FileTruncate(File file, pgoff_t offset, uint32 wait_event_info)
{
    int         returnCode;
 
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileTruncate %d (%s)",
               file, VfdCache[file].fileName));
 
    returnCode = FileAccess(file);
    if (returnCode < 0)
        return returnCode;
 
    pgstat_report_wait_start(wait_event_info);
    returnCode = pg_ftruncate(VfdCache[file].fd, offset);
    pgstat_report_wait_end();
 
    if (returnCode == 0 && VfdCache[file].fileSize > offset)
    {
        /* adjust our state for truncation of a temp file */
        Assert(VfdCache[file].fdstate & FD_TEMP_FILE_LIMIT);
        temporary_files_size -= VfdCache[file].fileSize - offset;
        VfdCache[file].fileSize = offset;
    }
 
    return returnCode;
}
 
/*
 * Return the pathname associated with an open file.
 *
 * The returned string points to an internal buffer, which is valid until
 * the file is closed.
 */
char *
FilePathName(File file)
{
    Assert(FileIsValid(file));
 
    return VfdCache[file].fileName;
}
 
/*
 * Return the raw file descriptor of an opened file.
 *
 * The returned file descriptor will be valid until the file is closed, but
 * there are a lot of things that can make that happen.  So the caller should
 * be careful not to do much of anything else before it finishes using the
 * returned file descriptor.
 */
int
FileGetRawDesc(File file)
{
    int         returnCode;
 
    returnCode = FileAccess(file);
    if (returnCode < 0)
        return returnCode;
 
    Assert(FileIsValid(file));
    return VfdCache[file].fd;
}
 
/*
 * FileGetRawFlags - returns the file flags on open(2)
 */
int
FileGetRawFlags(File file)
{
    Assert(FileIsValid(file));
    return VfdCache[file].fileFlags;
}
 
/*
 * FileGetRawMode - returns the mode bitmask passed to open(2)
 */
mode_t
FileGetRawMode(File file)
{
    Assert(FileIsValid(file));
    return VfdCache[file].fileMode;
}
 
/*
 * Make room for another allocatedDescs[] array entry if needed and possible.
 * Returns true if an array element is available.
 */
static bool
reserveAllocatedDesc(void)
{
    AllocateDesc *newDescs;
    int         newMax;
 
    /* Quick out if array already has a free slot. */
    if (numAllocatedDescs < maxAllocatedDescs)
        return true;
 
    /*
     * If the array hasn't yet been created in the current process, initialize
     * it with FD_MINFREE / 3 elements.  In many scenarios this is as many as
     * we will ever need, anyway.  We don't want to look at max_safe_fds
     * immediately because set_max_safe_fds() may not have run yet.
     */
    if (allocatedDescs == NULL)
    {
        newMax = FD_MINFREE / 3;
        newDescs = (AllocateDesc *) malloc(newMax * sizeof(AllocateDesc));
        /* Out of memory already?  Treat as fatal error. */
        if (newDescs == NULL)
            ereport(ERROR,
                    (errcode(ERRCODE_OUT_OF_MEMORY),
                     errmsg("out of memory")));
        allocatedDescs = newDescs;
        maxAllocatedDescs = newMax;
        return true;
    }
 
    /*
     * Consider enlarging the array beyond the initial allocation used above.
     * By the time this happens, max_safe_fds should be known accurately.
     *
     * We mustn't let allocated descriptors hog all the available FDs, and in
     * practice we'd better leave a reasonable number of FDs for VFD use.  So
     * set the maximum to max_safe_fds / 3.  (This should certainly be at
     * least as large as the initial size, FD_MINFREE / 3, so we aren't
     * tightening the restriction here.)  Recall that "external" FDs are
     * allowed to consume another third of max_safe_fds.
     */
    newMax = max_safe_fds / 3;
    if (newMax > maxAllocatedDescs)
    {
        newDescs = (AllocateDesc *) realloc(allocatedDescs,
                                            newMax * sizeof(AllocateDesc));
        /* Treat out-of-memory as a non-fatal error. */
        if (newDescs == NULL)
            return false;
        allocatedDescs = newDescs;
        maxAllocatedDescs = newMax;
        return true;
    }
 
    /* Can't enlarge allocatedDescs[] any more. */
    return false;
}
 
/*
 * Routines that want to use stdio (ie, FILE*) should use AllocateFile
 * rather than plain fopen().  This lets fd.c deal with freeing FDs if
 * necessary to open the file.  When done, call FreeFile rather than fclose.
 *
 * Note that files that will be open for any significant length of time
 * should NOT be handled this way, since they cannot share kernel file
 * descriptors with other files; there is grave risk of running out of FDs
 * if anyone locks down too many FDs.  Most callers of this routine are
 * simply reading a config file that they will read and close immediately.
 *
 * fd.c will automatically close all files opened with AllocateFile at
 * transaction commit or abort; this prevents FD leakage if a routine
 * that calls AllocateFile is terminated prematurely by ereport(ERROR).
 *
 * Ideally this should be the *only* direct call of fopen() in the backend.
 */
FILE *
AllocateFile(const char *name, const char *mode)
{
    FILE       *file;
 
    DO_DB(elog(LOG, "AllocateFile: Allocated %d (%s)",
               numAllocatedDescs, name));
 
    /* Can we allocate another non-virtual FD? */
    if (!reserveAllocatedDesc())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("exceeded maxAllocatedDescs (%d) while trying to open file \"%s\"",
                        maxAllocatedDescs, name)));
 
    /* Close excess kernel FDs. */
    ReleaseLruFiles();
 
TryAgain:
    if ((file = fopen(name, mode)) != NULL)
    {
        AllocateDesc *desc = &allocatedDescs[numAllocatedDescs];
 
        desc->kind = AllocateDescFile;
        desc->desc.file = file;
        desc->create_subid = GetCurrentSubTransactionId();
        numAllocatedDescs++;
        return desc->desc.file;
    }
 
    if (errno == EMFILE || errno == ENFILE)
    {
        int         save_errno = errno;
 
        ereport(LOG,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("out of file descriptors: %m; release and retry")));
        errno = 0;
        if (ReleaseLruFile())
            goto TryAgain;
        errno = save_errno;
    }
 
    return NULL;
}
 
/*
 * Open a file with OpenTransientFilePerm() and pass default file mode for
 * the fileMode parameter.
 */
int
OpenTransientFile(const char *fileName, int fileFlags)
{
    return OpenTransientFilePerm(fileName, fileFlags, pg_file_create_mode);
}
 
/*
 * Like AllocateFile, but returns an unbuffered fd like open(2)
 */
int
OpenTransientFilePerm(const char *fileName, int fileFlags, mode_t fileMode)
{
    int         fd;
 
    DO_DB(elog(LOG, "OpenTransientFile: Allocated %d (%s)",
               numAllocatedDescs, fileName));
 
    /* Can we allocate another non-virtual FD? */
    if (!reserveAllocatedDesc())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("exceeded maxAllocatedDescs (%d) while trying to open file \"%s\"",
                        maxAllocatedDescs, fileName)));
 
    /* Close excess kernel FDs. */
    ReleaseLruFiles();
 
    fd = BasicOpenFilePerm(fileName, fileFlags, fileMode);
 
    if (fd >= 0)
    {
        AllocateDesc *desc = &allocatedDescs[numAllocatedDescs];
 
        desc->kind = AllocateDescRawFD;
        desc->desc.fd = fd;
        desc->create_subid = GetCurrentSubTransactionId();
        numAllocatedDescs++;
 
        return fd;
    }
 
    return -1;                  /* failure */
}
 
/*
 * Routines that want to initiate a pipe stream should use OpenPipeStream
 * rather than plain popen().  This lets fd.c deal with freeing FDs if
 * necessary.  When done, call ClosePipeStream rather than pclose.
 *
 * This function also ensures that the popen'd program is run with default
 * SIGPIPE processing, rather than the SIG_IGN setting the backend normally
 * uses.  This ensures desirable response to, eg, closing a read pipe early.
 */
FILE *
OpenPipeStream(const char *command, const char *mode)
{
    FILE       *file;
    int         save_errno;
 
    DO_DB(elog(LOG, "OpenPipeStream: Allocated %d (%s)",
               numAllocatedDescs, command));
 
    /* Can we allocate another non-virtual FD? */
    if (!reserveAllocatedDesc())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("exceeded maxAllocatedDescs (%d) while trying to execute command \"%s\"",
                        maxAllocatedDescs, command)));
 
    /* Close excess kernel FDs. */
    ReleaseLruFiles();
 
TryAgain:
    fflush(NULL);
    pqsignal(SIGPIPE, SIG_DFL);
    errno = 0;
    file = popen(command, mode);
    save_errno = errno;
    pqsignal(SIGPIPE, SIG_IGN);
    errno = save_errno;
    if (file != NULL)
    {
        AllocateDesc *desc = &allocatedDescs[numAllocatedDescs];
 
        desc->kind = AllocateDescPipe;
        desc->desc.file = file;
        desc->create_subid = GetCurrentSubTransactionId();
        numAllocatedDescs++;
        return desc->desc.file;
    }
 
    if (errno == EMFILE || errno == ENFILE)
    {
        ereport(LOG,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("out of file descriptors: %m; release and retry")));
        if (ReleaseLruFile())
            goto TryAgain;
        errno = save_errno;
    }
 
    return NULL;
}
 
/*
 * Free an AllocateDesc of any type.
 *
 * The argument *must* point into the allocatedDescs[] array.
 */
static int
FreeDesc(AllocateDesc *desc)
{
    int         result;
 
    /* Close the underlying object */
    switch (desc->kind)
    {
        case AllocateDescFile:
            result = fclose(desc->desc.file);
            break;
        case AllocateDescPipe:
            result = pclose(desc->desc.file);
            break;
        case AllocateDescDir:
            result = closedir(desc->desc.dir);
            break;
        case AllocateDescRawFD:
            pgaio_closing_fd(desc->desc.fd);
            result = close(desc->desc.fd);
            break;
        default:
            elog(ERROR, "AllocateDesc kind not recognized");
            result = 0;         /* keep compiler quiet */
            break;
    }
 
    /* Compact storage in the allocatedDescs array */
    numAllocatedDescs--;
    *desc = allocatedDescs[numAllocatedDescs];
 
    return result;
}
 
/*
 * Close a file returned by AllocateFile.
 *
 * Note we do not check fclose's return value --- it is up to the caller
 * to handle close errors.
 */
int
FreeFile(FILE *file)
{
    int         i;
 
    DO_DB(elog(LOG, "FreeFile: Allocated %d", numAllocatedDescs));
 
    /* Remove file from list of allocated files, if it's present */
    for (i = numAllocatedDescs; --i >= 0;)
    {
        AllocateDesc *desc = &allocatedDescs[i];
 
        if (desc->kind == AllocateDescFile && desc->desc.file == file)
            return FreeDesc(desc);
    }
 
    /* Only get here if someone passes us a file not in allocatedDescs */
    elog(WARNING, "file passed to FreeFile was not obtained from AllocateFile");
 
    return fclose(file);
}
 
/*
 * Close a file returned by OpenTransientFile.
 *
 * Note we do not check close's return value --- it is up to the caller
 * to handle close errors.
 */
int
CloseTransientFile(int fd)
{
    int         i;
 
    DO_DB(elog(LOG, "CloseTransientFile: Allocated %d", numAllocatedDescs));
 
    /* Remove fd from list of allocated files, if it's present */
    for (i = numAllocatedDescs; --i >= 0;)
    {
        AllocateDesc *desc = &allocatedDescs[i];
 
        if (desc->kind == AllocateDescRawFD && desc->desc.fd == fd)
            return FreeDesc(desc);
    }
 
    /* Only get here if someone passes us a file not in allocatedDescs */
    elog(WARNING, "fd passed to CloseTransientFile was not obtained from OpenTransientFile");
 
    pgaio_closing_fd(fd);
 
    return close(fd);
}
 
/*
 * Routines that want to use <dirent.h> (ie, DIR*) should use AllocateDir
 * rather than plain opendir().  This lets fd.c deal with freeing FDs if
 * necessary to open the directory, and with closing it after an elog.
 * When done, call FreeDir rather than closedir.
 *
 * Returns NULL, with errno set, on failure.  Note that failure detection
 * is commonly left to the following call of ReadDir or ReadDirExtended;
 * see the comments for ReadDir.
 *
 * Ideally this should be the *only* direct call of opendir() in the backend.
 */
DIR *
AllocateDir(const char *dirname)
{
    DIR        *dir;
 
    DO_DB(elog(LOG, "AllocateDir: Allocated %d (%s)",
               numAllocatedDescs, dirname));
 
    /* Can we allocate another non-virtual FD? */
    if (!reserveAllocatedDesc())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("exceeded maxAllocatedDescs (%d) while trying to open directory \"%s\"",
                        maxAllocatedDescs, dirname)));
 
    /* Close excess kernel FDs. */
    ReleaseLruFiles();
 
TryAgain:
    if ((dir = opendir(dirname)) != NULL)
    {
        AllocateDesc *desc = &allocatedDescs[numAllocatedDescs];
 
        desc->kind = AllocateDescDir;
        desc->desc.dir = dir;
        desc->create_subid = GetCurrentSubTransactionId();
        numAllocatedDescs++;
        return desc->desc.dir;
    }
 
    if (errno == EMFILE || errno == ENFILE)
    {
        int         save_errno = errno;
 
        ereport(LOG,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("out of file descriptors: %m; release and retry")));
        errno = 0;
        if (ReleaseLruFile())
            goto TryAgain;
        errno = save_errno;
    }
 
    return NULL;
}
 
/*
 * Read a directory opened with AllocateDir, ereport'ing any error.
 *
 * This is easier to use than raw readdir() since it takes care of some
 * otherwise rather tedious and error-prone manipulation of errno.  Also,
 * if you are happy with a generic error message for AllocateDir failure,
 * you can just do
 *
 *      dir = AllocateDir(path);
 *      while ((dirent = ReadDir(dir, path)) != NULL)
 *          process dirent;
 *      FreeDir(dir);
 *
 * since a NULL dir parameter is taken as indicating AllocateDir failed.
 * (Make sure errno isn't changed between AllocateDir and ReadDir if you
 * use this shortcut.)
 *
 * The pathname passed to AllocateDir must be passed to this routine too,
 * but it is only used for error reporting.
 */
struct dirent *
ReadDir(DIR *dir, const char *dirname)
{
    return ReadDirExtended(dir, dirname, ERROR);
}
 
/*
 * Alternate version of ReadDir that allows caller to specify the elevel
 * for any error report (whether it's reporting an initial failure of
 * AllocateDir or a subsequent directory read failure).
 *
 * If elevel < ERROR, returns NULL after any error.  With the normal coding
 * pattern, this will result in falling out of the loop immediately as
 * though the directory contained no (more) entries.
 */
struct dirent *
ReadDirExtended(DIR *dir, const char *dirname, int elevel)
{
    struct dirent *dent;
 
    /* Give a generic message for AllocateDir failure, if caller didn't */
    if (dir == NULL)
    {
        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not open directory \"%s\": %m",
                        dirname)));
        return NULL;
    }
 
    errno = 0;
    if ((dent = readdir(dir)) != NULL)
        return dent;
 
    if (errno)
        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not read directory \"%s\": %m",
                        dirname)));
    return NULL;
}
 
/*
 * Close a directory opened with AllocateDir.
 *
 * Returns closedir's return value (with errno set if it's not 0).
 * Note we do not check the return value --- it is up to the caller
 * to handle close errors if wanted.
 *
 * Does nothing if dir == NULL; we assume that directory open failure was
 * already reported if desired.
 */
int
FreeDir(DIR *dir)
{
    int         i;
 
    /* Nothing to do if AllocateDir failed */
    if (dir == NULL)
        return 0;
 
    DO_DB(elog(LOG, "FreeDir: Allocated %d", numAllocatedDescs));
 
    /* Remove dir from list of allocated dirs, if it's present */
    for (i = numAllocatedDescs; --i >= 0;)
    {
        AllocateDesc *desc = &allocatedDescs[i];
 
        if (desc->kind == AllocateDescDir && desc->desc.dir == dir)
            return FreeDesc(desc);
    }
 
    /* Only get here if someone passes us a dir not in allocatedDescs */
    elog(WARNING, "dir passed to FreeDir was not obtained from AllocateDir");
 
    return closedir(dir);
}
 
 
/*
 * Close a pipe stream returned by OpenPipeStream.
 */
int
ClosePipeStream(FILE *file)
{
    int         i;
 
    DO_DB(elog(LOG, "ClosePipeStream: Allocated %d", numAllocatedDescs));
 
    /* Remove file from list of allocated files, if it's present */
    for (i = numAllocatedDescs; --i >= 0;)
    {
        AllocateDesc *desc = &allocatedDescs[i];
 
        if (desc->kind == AllocateDescPipe && desc->desc.file == file)
            return FreeDesc(desc);
    }
 
    /* Only get here if someone passes us a file not in allocatedDescs */
    elog(WARNING, "file passed to ClosePipeStream was not obtained from OpenPipeStream");
 
    return pclose(file);
}
 
/*
 * closeAllVfds
 *
 * Force all VFDs into the physically-closed state, so that the fewest
 * possible number of kernel file descriptors are in use.  There is no
 * change in the logical state of the VFDs.
 */
void
closeAllVfds(void)
{
    Index       i;
 
    if (SizeVfdCache > 0)
    {
        Assert(FileIsNotOpen(0));   /* Make sure ring not corrupted */
        for (i = 1; i < SizeVfdCache; i++)
        {
            if (!FileIsNotOpen(i))
                LruDelete(i);
        }
    }
}
 
 
/*
 * SetTempTablespaces
 *
 * Define a list (actually an array) of OIDs of tablespaces to use for
 * temporary files.  This list will be used until end of transaction,
 * unless this function is called again before then.  It is caller's
 * responsibility that the passed-in array has adequate lifespan (typically
 * it'd be allocated in TopTransactionContext).
 *
 * Some entries of the array may be InvalidOid, indicating that the current
 * database's default tablespace should be used.
 */
void
SetTempTablespaces(Oid *tableSpaces, int numSpaces)
{
    Assert(numSpaces >= 0);
    tempTableSpaces = tableSpaces;
    numTempTableSpaces = numSpaces;
 
    /*
     * Select a random starting point in the list.  This is to minimize
     * conflicts between backends that are most likely sharing the same list
     * of temp tablespaces.  Note that if we create multiple temp files in the
     * same transaction, we'll advance circularly through the list --- this
     * ensures that large temporary sort files are nicely spread across all
     * available tablespaces.
     */
    if (numSpaces > 1)
        nextTempTableSpace = pg_prng_uint64_range(&pg_global_prng_state,
                                                  0, numSpaces - 1);
    else
        nextTempTableSpace = 0;
}
 
/*
 * TempTablespacesAreSet
 *
 * Returns true if SetTempTablespaces has been called in current transaction.
 * (This is just so that tablespaces.c doesn't need its own per-transaction
 * state.)
 */
bool
TempTablespacesAreSet(void)
{
    return (numTempTableSpaces >= 0);
}
 
/*
 * GetTempTablespaces
 *
 * Populate an array with the OIDs of the tablespaces that should be used for
 * temporary files.  (Some entries may be InvalidOid, indicating that the
 * current database's default tablespace should be used.)  At most numSpaces
 * entries will be filled.
 * Returns the number of OIDs that were copied into the output array.
 */
int
GetTempTablespaces(Oid *tableSpaces, int numSpaces)
{
    int         i;
 
    Assert(TempTablespacesAreSet());
    for (i = 0; i < numTempTableSpaces && i < numSpaces; ++i)
        tableSpaces[i] = tempTableSpaces[i];
 
    return i;
}
 
/*
 * GetNextTempTableSpace
 *
 * Select the next temp tablespace to use.  A result of InvalidOid means
 * to use the current database's default tablespace.
 */
Oid
GetNextTempTableSpace(void)
{
    if (numTempTableSpaces > 0)
    {
        /* Advance nextTempTableSpace counter with wraparound */
        if (++nextTempTableSpace >= numTempTableSpaces)
            nextTempTableSpace = 0;
        return tempTableSpaces[nextTempTableSpace];
    }
    return InvalidOid;
}
 
 
/*
 * AtEOSubXact_Files
 *
 * Take care of subtransaction commit/abort.  At abort, we close AllocateDescs
 * that the subtransaction may have opened.  At commit, we reassign them to
 * the parent subtransaction.  (Temporary files are tracked by ResourceOwners
 * instead.)
 */
void
AtEOSubXact_Files(bool isCommit, SubTransactionId mySubid,
                  SubTransactionId parentSubid)
{
    Index       i;
 
    for (i = 0; i < numAllocatedDescs; i++)
    {
        if (allocatedDescs[i].create_subid == mySubid)
        {
            if (isCommit)
                allocatedDescs[i].create_subid = parentSubid;
            else
            {
                /* have to recheck the item after FreeDesc (ugly) */
                FreeDesc(&allocatedDescs[i--]);
            }
        }
    }
}
 
/*
 * AtEOXact_Files
 *
 * This routine is called during transaction commit or abort.  All still-open
 * per-transaction temporary file VFDs are closed, which also causes the
 * underlying files to be deleted (although they should've been closed already
 * by the ResourceOwner cleanup). Furthermore, all "allocated" stdio files are
 * closed. We also forget any transaction-local temp tablespace list.
 *
 * The isCommit flag is used only to decide whether to emit warnings about
 * unclosed files.
 */
void
AtEOXact_Files(bool isCommit)
{
    CleanupTempFiles(isCommit, false);
    tempTableSpaces = NULL;
    numTempTableSpaces = -1;
}
 
/*
 * BeforeShmemExit_Files
 *
 * before_shmem_exit hook to clean up temp files during backend shutdown.
 * Here, we want to clean up *all* temp files including interXact ones.
 */
static void
BeforeShmemExit_Files(int code, Datum arg)
{
    CleanupTempFiles(false, true);
 
    /* prevent further temp files from being created */
#ifdef USE_ASSERT_CHECKING
    temporary_files_allowed = false;
#endif
}
 
/*
 * Close temporary files and delete their underlying files.
 *
 * isCommit: if true, this is normal transaction commit, and we don't
 * expect any remaining files; warn if there are some.
 *
 * isProcExit: if true, this is being called as the backend process is
 * exiting. If that's the case, we should remove all temporary files; if
 * that's not the case, we are being called for transaction commit/abort
 * and should only remove transaction-local temp files.  In either case,
 * also clean up "allocated" stdio files, dirs and fds.
 */
static void
CleanupTempFiles(bool isCommit, bool isProcExit)
{
    Index       i;
 
    /*
     * Careful here: at proc_exit we need extra cleanup, not just
     * xact_temporary files.
     */
    if (isProcExit || have_xact_temporary_files)
    {
        Assert(FileIsNotOpen(0));   /* Make sure ring not corrupted */
        for (i = 1; i < SizeVfdCache; i++)
        {
            unsigned short fdstate = VfdCache[i].fdstate;
 
            if (((fdstate & FD_DELETE_AT_CLOSE) || (fdstate & FD_CLOSE_AT_EOXACT)) &&
                VfdCache[i].fileName != NULL)
            {
                /*
                 * If we're in the process of exiting a backend process, close
                 * all temporary files. Otherwise, only close temporary files
                 * local to the current transaction. They should be closed by
                 * the ResourceOwner mechanism already, so this is just a
                 * debugging cross-check.
                 */
                if (isProcExit)
                    FileClose(i);
                else if (fdstate & FD_CLOSE_AT_EOXACT)
                {
                    elog(WARNING,
                         "temporary file %s not closed at end-of-transaction",
                         VfdCache[i].fileName);
                    FileClose(i);
                }
            }
        }
 
        have_xact_temporary_files = false;
    }
 
    /* Complain if any allocated files remain open at commit. */
    if (isCommit && numAllocatedDescs > 0)
        elog(WARNING, "%d temporary files and directories not closed at end-of-transaction",
             numAllocatedDescs);
 
    /* Clean up "allocated" stdio files, dirs and fds. */
    while (numAllocatedDescs > 0)
        FreeDesc(&allocatedDescs[0]);
}
 
 
/*
 * Remove temporary and temporary relation files left over from a prior
 * postmaster session
 *
 * This should be called during postmaster startup.  It will forcibly
 * remove any leftover files created by OpenTemporaryFile and any leftover
 * temporary relation files created by mdcreate.
 *
 * During post-backend-crash restart cycle, this routine is called when
 * remove_temp_files_after_crash GUC is enabled. Multiple crashes while
 * queries are using temp files could result in useless storage usage that can
 * only be reclaimed by a service restart. The argument against enabling it is
 * that someone might want to examine the temporary files for debugging
 * purposes. This does however mean that OpenTemporaryFile had better allow for
 * collision with an existing temp file name.
 *
 * NOTE: this function and its subroutines generally report syscall failures
 * with ereport(LOG) and keep going.  Removing temp files is not so critical
 * that we should fail to start the database when we can't do it.
 */
void
RemovePgTempFiles(void)
{
    char        temp_path[MAXPGPATH + sizeof(PG_TBLSPC_DIR) + sizeof(TABLESPACE_VERSION_DIRECTORY) + sizeof(PG_TEMP_FILES_DIR)];
    DIR        *spc_dir;
    struct dirent *spc_de;
 
    /*
     * First process temp files in pg_default ($PGDATA/base)
     */
    snprintf(temp_path, sizeof(temp_path), "base/%s", PG_TEMP_FILES_DIR);
    RemovePgTempFilesInDir(temp_path, true, false);
    RemovePgTempRelationFiles("base");
 
    /*
     * Cycle through temp directories for all non-default tablespaces.
     */
    spc_dir = AllocateDir(PG_TBLSPC_DIR);
 
    while ((spc_de = ReadDirExtended(spc_dir, PG_TBLSPC_DIR, LOG)) != NULL)
    {
        if (strcmp(spc_de->d_name, ".") == 0 ||
            strcmp(spc_de->d_name, "..") == 0)
            continue;
 
        snprintf(temp_path, sizeof(temp_path), "%s/%s/%s/%s",
                 PG_TBLSPC_DIR, spc_de->d_name, TABLESPACE_VERSION_DIRECTORY,
                 PG_TEMP_FILES_DIR);
        RemovePgTempFilesInDir(temp_path, true, false);
 
        snprintf(temp_path, sizeof(temp_path), "%s/%s/%s",
                 PG_TBLSPC_DIR, spc_de->d_name, TABLESPACE_VERSION_DIRECTORY);
        RemovePgTempRelationFiles(temp_path);
    }
 
    FreeDir(spc_dir);
 
    /*
     * In EXEC_BACKEND case there is a pgsql_tmp directory at the top level of
     * DataDir as well.  However, that is *not* cleaned here because doing so
     * would create a race condition.  It's done separately, earlier in
     * postmaster startup.
     */
}
 
/*
 * Process one pgsql_tmp directory for RemovePgTempFiles.
 *
 * If missing_ok is true, it's all right for the named directory to not exist.
 * Any other problem results in a LOG message.  (missing_ok should be true at
 * the top level, since pgsql_tmp directories are not created until needed.)
 *
 * At the top level, this should be called with unlink_all = false, so that
 * only files matching the temporary name prefix will be unlinked.  When
 * recursing it will be called with unlink_all = true to unlink everything
 * under a top-level temporary directory.
 *
 * (These two flags could be replaced by one, but it seems clearer to keep
 * them separate.)
 */
void
RemovePgTempFilesInDir(const char *tmpdirname, bool missing_ok, bool unlink_all)
{
    DIR        *temp_dir;
    struct dirent *temp_de;
    char        rm_path[MAXPGPATH * 2];
 
    temp_dir = AllocateDir(tmpdirname);
 
    if (temp_dir == NULL && errno == ENOENT && missing_ok)
        return;
 
    while ((temp_de = ReadDirExtended(temp_dir, tmpdirname, LOG)) != NULL)
    {
        if (strcmp(temp_de->d_name, ".") == 0 ||
            strcmp(temp_de->d_name, "..") == 0)
            continue;
 
        snprintf(rm_path, sizeof(rm_path), "%s/%s",
                 tmpdirname, temp_de->d_name);
 
        if (unlink_all ||
            strncmp(temp_de->d_name,
                    PG_TEMP_FILE_PREFIX,
                    strlen(PG_TEMP_FILE_PREFIX)) == 0)
        {
            PGFileType  type = get_dirent_type(rm_path, temp_de, false, LOG);
 
            if (type == PGFILETYPE_ERROR)
                continue;
            else if (type == PGFILETYPE_DIR)
            {
                /* recursively remove contents, then directory itself */
                RemovePgTempFilesInDir(rm_path, false, true);
 
                if (rmdir(rm_path) < 0)
                    ereport(LOG,
                            (errcode_for_file_access(),
                             errmsg("could not remove directory \"%s\": %m",
                                    rm_path)));
            }
            else
            {
                if (unlink(rm_path) < 0)
                    ereport(LOG,
                            (errcode_for_file_access(),
                             errmsg("could not remove file \"%s\": %m",
                                    rm_path)));
            }
        }
        else
            ereport(LOG,
                    (errmsg("unexpected file found in temporary-files directory: \"%s\"",
                            rm_path)));
    }
 
    FreeDir(temp_dir);
}
 
/* Process one tablespace directory, look for per-DB subdirectories */
static void
RemovePgTempRelationFiles(const char *tsdirname)
{
    DIR        *ts_dir;
    struct dirent *de;
    char        dbspace_path[MAXPGPATH * 2];
 
    ts_dir = AllocateDir(tsdirname);
 
    while ((de = ReadDirExtended(ts_dir, tsdirname, LOG)) != NULL)
    {
        /*
         * We're only interested in the per-database directories, which have
         * numeric names.  Note that this code will also (properly) ignore "."
         * and "..".
         */
        if (strspn(de->d_name, "0123456789") != strlen(de->d_name))
            continue;
 
        snprintf(dbspace_path, sizeof(dbspace_path), "%s/%s",
                 tsdirname, de->d_name);
        RemovePgTempRelationFilesInDbspace(dbspace_path);
    }
 
    FreeDir(ts_dir);
}
 
/* Process one per-dbspace directory for RemovePgTempRelationFiles */
static void
RemovePgTempRelationFilesInDbspace(const char *dbspacedirname)
{
    DIR        *dbspace_dir;
    struct dirent *de;
    char        rm_path[MAXPGPATH * 2];
 
    dbspace_dir = AllocateDir(dbspacedirname);
 
    while ((de = ReadDirExtended(dbspace_dir, dbspacedirname, LOG)) != NULL)
    {
        if (!looks_like_temp_rel_name(de->d_name))
            continue;
 
        snprintf(rm_path, sizeof(rm_path), "%s/%s",
                 dbspacedirname, de->d_name);
 
        if (unlink(rm_path) < 0)
            ereport(LOG,
                    (errcode_for_file_access(),
                     errmsg("could not remove file \"%s\": %m",
                            rm_path)));
    }
 
    FreeDir(dbspace_dir);
}
 
/* t<digits>_<digits>, or t<digits>_<digits>_<forkname> */
bool
looks_like_temp_rel_name(const char *name)
{
    int         pos;
    int         savepos;
 
    /* Must start with "t". */
    if (name[0] != 't')
        return false;
 
    /* Followed by a non-empty string of digits and then an underscore. */
    for (pos = 1; isdigit((unsigned char) name[pos]); ++pos)
        ;
    if (pos == 1 || name[pos] != '_')
        return false;
 
    /* Followed by another nonempty string of digits. */
    for (savepos = ++pos; isdigit((unsigned char) name[pos]); ++pos)
        ;
    if (savepos == pos)
        return false;
 
    /* We might have _forkname or .segment or both. */
    if (name[pos] == '_')
    {
        int         forkchar = forkname_chars(&name[pos + 1], NULL);
 
        if (forkchar <= 0)
            return false;
        pos += forkchar + 1;
    }
    if (name[pos] == '.')
    {
        int         segchar;
 
        for (segchar = 1; isdigit((unsigned char) name[pos + segchar]); ++segchar)
            ;
        if (segchar <= 1)
            return false;
        pos += segchar;
    }
 
    /* Now we should be at the end. */
    if (name[pos] != '\0')
        return false;
    return true;
}
 
#ifdef HAVE_SYNCFS
static void
do_syncfs(const char *path)
{
    int         fd;
 
    ereport_startup_progress("syncing data directory (syncfs), elapsed time: %ld.%02d s, current path: %s",
                             path);
 
    fd = OpenTransientFile(path, O_RDONLY);
    if (fd < 0)
    {
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not open file \"%s\": %m", path)));
        return;
    }
    if (syncfs(fd) < 0)
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not synchronize file system for file \"%s\": %m", path)));
    CloseTransientFile(fd);
}
#endif
 
/*
 * Issue fsync recursively on PGDATA and all its contents, or issue syncfs for
 * all potential filesystem, depending on recovery_init_sync_method setting.
 *
 * We fsync regular files and directories wherever they are, but we
 * follow symlinks only for pg_wal and immediately under pg_tblspc.
 * Other symlinks are presumed to point at files we're not responsible
 * for fsyncing, and might not have privileges to write at all.
 *
 * Errors are logged but not considered fatal; that's because this is used
 * only during database startup, to deal with the possibility that there are
 * issued-but-unsynced writes pending against the data directory.  We want to
 * ensure that such writes reach disk before anything that's done in the new
 * run.  However, aborting on error would result in failure to start for
 * harmless cases such as read-only files in the data directory, and that's
 * not good either.
 *
 * Note that if we previously crashed due to a PANIC on fsync(), we'll be
 * rewriting all changes again during recovery.
 *
 * Note we assume we're chdir'd into PGDATA to begin with.
 */
void
SyncDataDirectory(void)
{
    bool        xlog_is_symlink;
 
    /* We can skip this whole thing if fsync is disabled. */
    if (!enableFsync)
        return;
 
    /*
     * If pg_wal is a symlink, we'll need to recurse into it separately,
     * because the first walkdir below will ignore it.
     */
    xlog_is_symlink = false;
 
    {
        struct stat st;
 
        if (lstat("pg_wal", &st) < 0)
            ereport(LOG,
                    (errcode_for_file_access(),
                     errmsg("could not stat file \"%s\": %m",
                            "pg_wal")));
        else if (S_ISLNK(st.st_mode))
            xlog_is_symlink = true;
    }
 
#ifdef HAVE_SYNCFS
    if (recovery_init_sync_method == DATA_DIR_SYNC_METHOD_SYNCFS)
    {
        DIR        *dir;
        struct dirent *de;
 
        /*
         * On Linux, we don't have to open every single file one by one.  We
         * can use syncfs() to sync whole filesystems.  We only expect
         * filesystem boundaries to exist where we tolerate symlinks, namely
         * pg_wal and the tablespaces, so we call syncfs() for each of those
         * directories.
         */
 
        /* Prepare to report progress syncing the data directory via syncfs. */
        begin_startup_progress_phase();
 
        /* Sync the top level pgdata directory. */
        do_syncfs(".");
        /* If any tablespaces are configured, sync each of those. */
        dir = AllocateDir(PG_TBLSPC_DIR);
        while ((de = ReadDirExtended(dir, PG_TBLSPC_DIR, LOG)))
        {
            char        path[MAXPGPATH];
 
            if (strcmp(de->d_name, ".") == 0 || strcmp(de->d_name, "..") == 0)
                continue;
 
            snprintf(path, MAXPGPATH, "%s/%s", PG_TBLSPC_DIR, de->d_name);
            do_syncfs(path);
        }
        FreeDir(dir);
        /* If pg_wal is a symlink, process that too. */
        if (xlog_is_symlink)
            do_syncfs("pg_wal");
        return;
    }
#endif                          /* !HAVE_SYNCFS */
 
#ifdef PG_FLUSH_DATA_WORKS
    /* Prepare to report progress of the pre-fsync phase. */
    begin_startup_progress_phase();
 
    /*
     * If possible, hint to the kernel that we're soon going to fsync the data
     * directory and its contents.  Errors in this step are even less
     * interesting than normal, so log them only at DEBUG1.
     */
    walkdir(".", pre_sync_fname, false, DEBUG1);
    if (xlog_is_symlink)
        walkdir("pg_wal", pre_sync_fname, false, DEBUG1);
    walkdir(PG_TBLSPC_DIR, pre_sync_fname, true, DEBUG1);
#endif
 
    /* Prepare to report progress syncing the data directory via fsync. */
    begin_startup_progress_phase();
 
    /*
     * Now we do the fsync()s in the same order.
     *
     * The main call ignores symlinks, so in addition to specially processing
     * pg_wal if it's a symlink, pg_tblspc has to be visited separately with
     * process_symlinks = true.  Note that if there are any plain directories
     * in pg_tblspc, they'll get fsync'd twice.  That's not an expected case
     * so we don't worry about optimizing it.
     */
    walkdir(".", datadir_fsync_fname, false, LOG);
    if (xlog_is_symlink)
        walkdir("pg_wal", datadir_fsync_fname, false, LOG);
    walkdir(PG_TBLSPC_DIR, datadir_fsync_fname, true, LOG);
}
 
/*
 * walkdir: recursively walk a directory, applying the action to each
 * regular file and directory (including the named directory itself).
 *
 * If process_symlinks is true, the action and recursion are also applied
 * to regular files and directories that are pointed to by symlinks in the
 * given directory; otherwise symlinks are ignored.  Symlinks are always
 * ignored in subdirectories, ie we intentionally don't pass down the
 * process_symlinks flag to recursive calls.
 *
 * Errors are reported at level elevel, which might be ERROR or less.
 *
 * See also walkdir in file_utils.c, which is a frontend version of this
 * logic.
 */
static void
walkdir(const char *path,
        void (*action) (const char *fname, bool isdir, int elevel),
        bool process_symlinks,
        int elevel)
{
    DIR        *dir;
    struct dirent *de;
 
    dir = AllocateDir(path);
 
    while ((de = ReadDirExtended(dir, path, elevel)) != NULL)
    {
        char        subpath[MAXPGPATH * 2];
 
        CHECK_FOR_INTERRUPTS();
 
        if (strcmp(de->d_name, ".") == 0 ||
            strcmp(de->d_name, "..") == 0)
            continue;
 
        snprintf(subpath, sizeof(subpath), "%s/%s", path, de->d_name);
 
        switch (get_dirent_type(subpath, de, process_symlinks, elevel))
        {
            case PGFILETYPE_REG:
                (*action) (subpath, false, elevel);
                break;
            case PGFILETYPE_DIR:
                walkdir(subpath, action, false, elevel);
                break;
            default:
 
                /*
                 * Errors are already reported directly by get_dirent_type(),
                 * and any remaining symlinks and unknown file types are
                 * ignored.
                 */
                break;
        }
    }
 
    FreeDir(dir);               /* we ignore any error here */
 
    /*
     * It's important to fsync the destination directory itself as individual
     * file fsyncs don't guarantee that the directory entry for the file is
     * synced.  However, skip this if AllocateDir failed; the action function
     * might not be robust against that.
     */
    if (dir)
        (*action) (path, true, elevel);
}
 
 
/*
 * Hint to the OS that it should get ready to fsync() this file.
 *
 * Ignores errors trying to open unreadable files, and logs other errors at a
 * caller-specified level.
 */
#ifdef PG_FLUSH_DATA_WORKS
 
static void
pre_sync_fname(const char *fname, bool isdir, int elevel)
{
    int         fd;
 
    /* Don't try to flush directories, it'll likely just fail */
    if (isdir)
        return;
 
    ereport_startup_progress("syncing data directory (pre-fsync), elapsed time: %ld.%02d s, current path: %s",
                             fname);
 
    fd = OpenTransientFile(fname, O_RDONLY | PG_BINARY);
 
    if (fd < 0)
    {
        if (errno == EACCES)
            return;
        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not open file \"%s\": %m", fname)));
        return;
    }
 
    /*
     * pg_flush_data() ignores errors, which is ok because this is only a
     * hint.
     */
    pg_flush_data(fd, 0, 0);
 
    if (CloseTransientFile(fd) != 0)
        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not close file \"%s\": %m", fname)));
}
 
#endif                          /* PG_FLUSH_DATA_WORKS */
 
static void
datadir_fsync_fname(const char *fname, bool isdir, int elevel)
{
    ereport_startup_progress("syncing data directory (fsync), elapsed time: %ld.%02d s, current path: %s",
                             fname);
 
    /*
     * We want to silently ignoring errors about unreadable files.  Pass that
     * desire on to fsync_fname_ext().
     */
    fsync_fname_ext(fname, isdir, true, elevel);
}
 
static void
unlink_if_exists_fname(const char *fname, bool isdir, int elevel)
{
    if (isdir)
    {
        if (rmdir(fname) != 0 && errno != ENOENT)
            ereport(elevel,
                    (errcode_for_file_access(),
                     errmsg("could not remove directory \"%s\": %m", fname)));
    }
    else
    {
        /* Use PathNameDeleteTemporaryFile to report filesize */
        PathNameDeleteTemporaryFile(fname, false);
    }
}
 
/*
 * fsync_fname_ext -- Try to fsync a file or directory
 *
 * If ignore_perm is true, ignore errors upon trying to open unreadable
 * files. Logs other errors at a caller-specified level.
 *
 * Returns 0 if the operation succeeded, -1 otherwise.
 */
int
fsync_fname_ext(const char *fname, bool isdir, bool ignore_perm, int elevel)
{
    int         fd;
    int         flags;
    int         returncode;
 
    /*
     * Some OSs require directories to be opened read-only whereas other
     * systems don't allow us to fsync files opened read-only; so we need both
     * cases here.  Using O_RDWR will cause us to fail to fsync files that are
     * not writable by our userid, but we assume that's OK.
     */
    flags = PG_BINARY;
    if (!isdir)
        flags |= O_RDWR;
    else
        flags |= O_RDONLY;
 
    fd = OpenTransientFile(fname, flags);
 
    /*
     * Some OSs don't allow us to open directories at all (Windows returns
     * EACCES), just ignore the error in that case.  If desired also silently
     * ignoring errors about unreadable files. Log others.
     */
    if (fd < 0 && isdir && (errno == EISDIR || errno == EACCES))
        return 0;
    else if (fd < 0 && ignore_perm && errno == EACCES)
        return 0;
    else if (fd < 0)
    {
        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not open file \"%s\": %m", fname)));
        return -1;
    }
 
    returncode = pg_fsync(fd);
 
    /*
     * Some OSes don't allow us to fsync directories at all, so we can ignore
     * those errors. Anything else needs to be logged.
     */
    if (returncode != 0 && !(isdir && (errno == EBADF || errno == EINVAL)))
    {
        int         save_errno;
 
        /* close file upon error, might not be in transaction context */
        save_errno = errno;
        (void) CloseTransientFile(fd);
        errno = save_errno;
 
        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not fsync file \"%s\": %m", fname)));
        return -1;
    }
 
    if (CloseTransientFile(fd) != 0)
    {
        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not close file \"%s\": %m", fname)));
        return -1;
    }
 
    return 0;
}
 
/*
 * fsync_parent_path -- fsync the parent path of a file or directory
 *
 * This is aimed at making file operations persistent on disk in case of
 * an OS crash or power failure.
 */
static int
fsync_parent_path(const char *fname, int elevel)
{
    char        parentpath[MAXPGPATH];
 
    strlcpy(parentpath, fname, MAXPGPATH);
    get_parent_directory(parentpath);
 
    /*
     * get_parent_directory() returns an empty string if the input argument is
     * just a file name (see comments in path.c), so handle that as being the
     * current directory.
     */
    if (strlen(parentpath) == 0)
        strlcpy(parentpath, ".", MAXPGPATH);
 
    if (fsync_fname_ext(parentpath, true, false, elevel) != 0)
        return -1;
 
    return 0;
}
 
/*
 * Create a PostgreSQL data sub-directory
 *
 * The data directory itself, and most of its sub-directories, are created at
 * initdb time, but we do have some occasions when we create directories in
 * the backend (CREATE TABLESPACE, for example).  In those cases, we want to
 * make sure that those directories are created consistently.  Today, that means
 * making sure that the created directory has the correct permissions, which is
 * what pg_dir_create_mode tracks for us.
 *
 * Note that we also set the umask() based on what we understand the correct
 * permissions to be (see file_perm.c).
 *
 * For permissions other than the default, mkdir() can be used directly, but
 * be sure to consider carefully such cases -- a sub-directory with incorrect
 * permissions in a PostgreSQL data directory could cause backups and other
 * processes to fail.
 */
int
MakePGDirectory(const char *directoryName)
{
    return mkdir(directoryName, pg_dir_create_mode);
}
 
/*
 * Return the passed-in error level, or PANIC if data_sync_retry is off.
 *
 * Failure to fsync any data file is cause for immediate panic, unless
 * data_sync_retry is enabled.  Data may have been written to the operating
 * system and removed from our buffer pool already, and if we are running on
 * an operating system that forgets dirty data on write-back failure, there
 * may be only one copy of the data remaining: in the WAL.  A later attempt to
 * fsync again might falsely report success.  Therefore we must not allow any
 * further checkpoints to be attempted.  data_sync_retry can in theory be
 * enabled on systems known not to drop dirty buffered data on write-back
 * failure (with the likely outcome that checkpoints will continue to fail
 * until the underlying problem is fixed).
 *
 * Any code that reports a failure from fsync() or related functions should
 * filter the error level with this function.
 */
int
data_sync_elevel(int elevel)
{
    return data_sync_retry ? elevel : PANIC;
}
 
bool
check_debug_io_direct(char **newval, void **extra, GucSource source)
{
    bool        result = true;
    int         flags;
 
#if PG_O_DIRECT == 0
    if (strcmp(*newval, "") != 0)
    {
        GUC_check_errdetail("\"%s\" is not supported on this platform.",
                            "debug_io_direct");
        result = false;
    }
    flags = 0;
#else
    List       *elemlist;
    ListCell   *l;
    char       *rawstring;
 
    /* Need a modifiable copy of string */
    rawstring = pstrdup(*newval);
 
    if (!SplitGUCList(rawstring, ',', &elemlist))
    {
        GUC_check_errdetail("Invalid list syntax in parameter \"%s\".",
                            "debug_io_direct");
        pfree(rawstring);
        list_free(elemlist);
        return false;
    }
 
    flags = 0;
    foreach(l, elemlist)
    {
        char       *item = (char *) lfirst(l);
 
        if (pg_strcasecmp(item, "data") == 0)
            flags |= IO_DIRECT_DATA;
        else if (pg_strcasecmp(item, "wal") == 0)
            flags |= IO_DIRECT_WAL;
        else if (pg_strcasecmp(item, "wal_init") == 0)
            flags |= IO_DIRECT_WAL_INIT;
        else
        {
            GUC_check_errdetail("Invalid option \"%s\".", item);
            result = false;
            break;
        }
    }
 
    /*
     * It's possible to configure block sizes smaller than our assumed I/O
     * alignment size, which could result in invalid I/O requests.
     */
#if XLOG_BLCKSZ < PG_IO_ALIGN_SIZE
    if (result && (flags & (IO_DIRECT_WAL | IO_DIRECT_WAL_INIT)))
    {
        GUC_check_errdetail("\"%s\" is not supported for WAL because %s is too small.",
                            "debug_io_direct", "XLOG_BLCKSZ");
        result = false;
    }
#endif
#if BLCKSZ < PG_IO_ALIGN_SIZE
    if (result && (flags & IO_DIRECT_DATA))
    {
        GUC_check_errdetail("\"%s\" is not supported for data because %s is too small.",
                            "debug_io_direct", "BLCKSZ");
        result = false;
    }
#endif
 
    pfree(rawstring);
    list_free(elemlist);
#endif
 
    if (!result)
        return result;
 
    /* Save the flags in *extra, for use by assign_debug_io_direct */
    *extra = guc_malloc(LOG, sizeof(int));
    if (!*extra)
        return false;
    *((int *) *extra) = flags;
 
    return result;
}
 
void
assign_debug_io_direct(const char *newval, void *extra)
{
    int        *flags = (int *) extra;
 
    io_direct_flags = *flags;
}
 
/* ResourceOwner callbacks */
 
static void
ResOwnerReleaseFile(Datum res)
{
    File        file = (File) DatumGetInt32(res);
    Vfd        *vfdP;
 
    Assert(FileIsValid(file));
 
    vfdP = &VfdCache[file];
    vfdP->resowner = NULL;
 
    FileClose(file);
}
 
static char *
ResOwnerPrintFile(Datum res)
{
    return psprintf("File %d", DatumGetInt32(res));
}

FD_CLOSE_AT_EOXACT

#define FD_CLOSE_AT_EOXACT   (1 << 1) /* T = close at eoXact */

Definition at line 196 of file fd.c.

FD_DELETE_AT_CLOSE

#define FD_DELETE_AT_CLOSE   (1 << 0) /* T = delete when closed */

Definition at line 195 of file fd.c.

FD_MINFREE

#define FD_MINFREE   48

Definition at line 138 of file fd.c.

FD_TEMP_FILE_LIMIT

#define FD_TEMP_FILE_LIMIT   (1 << 2) /* T = respect temp_file_limit */

Definition at line 197 of file fd.c.

FileIsNotOpen

#define FileIsNotOpen

(

file

)

(VfdCache[file].fd == VFD_CLOSED)

Definition at line 192 of file fd.c.

FileIsValid

#define FileIsValid

(

file

)

((file) > 0 && (file) < (int) SizeVfdCache && VfdCache[file].fileName != NULL)

Definition at line 189 of file fd.c.

NUM_RESERVED_FDS

#define NUM_RESERVED_FDS   10

Definition at line 129 of file fd.c.

VFD_CLOSED

#define VFD_CLOSED   (-1)

Definition at line 187 of file fd.c.

Typedef Documentation

Vfd

typedef struct vfd Vfd

Enumeration Type Documentation

AllocateDescKind

enum AllocateDescKind

Enumerator
AllocateDescFile
AllocateDescPipe
AllocateDescDir
AllocateDescRawFD

Definition at line 250 of file fd.c.

{
    AllocateDescFile,
    AllocateDescPipe,
    AllocateDescDir,
    AllocateDescRawFD,
} AllocateDescKind;

Function Documentation

AcquireExternalFD()

bool AcquireExternalFD

(

void

)

Definition at line 1171 of file fd.c.

{
    /*
     * We don't want more than max_safe_fds / 3 FDs to be consumed for
     * "external" FDs.
     */
    if (numExternalFDs < max_safe_fds / 3)
    {
        ReserveExternalFD();
        return true;
    }
    errno = EMFILE;
    return false;
}

References fb(), max_safe_fds, numExternalFDs, and ReserveExternalFD().

Referenced by CreateWaitEventSet(), and libpqsrv_connect_prepare().

AllocateDir()

DIR * AllocateDir

(

const char *

dirname

)

Definition at line 2890 of file fd.c.

{
    DIR        *dir;
 
    DO_DB(elog(LOG, "AllocateDir: Allocated %d (%s)",
               numAllocatedDescs, dirname));
 
    /* Can we allocate another non-virtual FD? */
    if (!reserveAllocatedDesc())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("exceeded maxAllocatedDescs (%d) while trying to open directory \"%s\"",
                        maxAllocatedDescs, dirname)));
 
    /* Close excess kernel FDs. */
    ReleaseLruFiles();
 
TryAgain:
    if ((dir = opendir(dirname)) != NULL)
    {
        AllocateDesc *desc = &allocatedDescs[numAllocatedDescs];
 
        desc->kind = AllocateDescDir;
        desc->desc.dir = dir;
        desc->create_subid = GetCurrentSubTransactionId();
        numAllocatedDescs++;
        return desc->desc.dir;
    }
 
    if (errno == EMFILE || errno == ENFILE)
    {
        int         save_errno = errno;
 
        ereport(LOG,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("out of file descriptors: %m; release and retry")));
        errno = 0;
        if (ReleaseLruFile())
            goto TryAgain;
        errno = save_errno;
    }
 
    return NULL;
}

References allocatedDescs, AllocateDescDir, AllocateDesc::create_subid, AllocateDesc::desc, AllocateDesc::dir, DO_DB, elog, ereport, errcode(), errmsg(), ERROR, fb(), GetCurrentSubTransactionId(), AllocateDesc::kind, LOG, maxAllocatedDescs, numAllocatedDescs, opendir(), ReleaseLruFile(), ReleaseLruFiles(), and reserveAllocatedDesc().

Referenced by calculate_database_size(), calculate_tablespace_size(), CheckPointLogicalRewriteHeap(), CheckPointSnapBuild(), CheckTablespaceDirectory(), CleanupBackupHistory(), copydir(), db_dir_size(), DeleteAllExportedSnapshotFiles(), destroy_tablespace_directories(), directory_is_empty(), do_pg_backup_start(), dsm_cleanup_for_mmap(), extension_file_exists(), get_ext_ver_list(), GetConfFilesInDir(), getInstallationPaths(), GetWalSummaries(), movedb(), ParseTzFile(), perform_base_backup(), pg_available_extension_versions(), pg_available_extensions(), pg_ls_dir(), pg_ls_dir_files(), pg_tablespace_databases(), pg_tzenumerate_next(), pg_tzenumerate_start(), pgarch_readyXlog(), RelationCacheInitFileRemove(), RelationCacheInitFileRemoveInDir(), RemoveNonParentXlogFiles(), RemoveOldXlogFiles(), RemovePgTempFiles(), RemovePgTempFilesInDir(), RemovePgTempRelationFiles(), RemovePgTempRelationFilesInDbspace(), RemoveTempXlogFiles(), ReorderBufferCleanupSerializedTXNs(), ResetUnloggedRelations(), ResetUnloggedRelationsInDbspaceDir(), ResetUnloggedRelationsInTablespaceDir(), restoreTwoPhaseData(), scan_directory_ci(), sendDir(), SlruScanDirectory(), StartupReorderBuffer(), StartupReplicationSlots(), SyncDataDirectory(), UpdateLogicalMappings(), walkdir(), and XLogGetOldestSegno().

AllocateFile()

FILE * AllocateFile	(	const char *	name,
		const char *	mode
	)

Definition at line 2627 of file fd.c.

{
    FILE       *file;
 
    DO_DB(elog(LOG, "AllocateFile: Allocated %d (%s)",
               numAllocatedDescs, name));
 
    /* Can we allocate another non-virtual FD? */
    if (!reserveAllocatedDesc())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("exceeded maxAllocatedDescs (%d) while trying to open file \"%s\"",
                        maxAllocatedDescs, name)));
 
    /* Close excess kernel FDs. */
    ReleaseLruFiles();
 
TryAgain:
    if ((file = fopen(name, mode)) != NULL)
    {
        AllocateDesc *desc = &allocatedDescs[numAllocatedDescs];
 
        desc->kind = AllocateDescFile;
        desc->desc.file = file;
        desc->create_subid = GetCurrentSubTransactionId();
        numAllocatedDescs++;
        return desc->desc.file;
    }
 
    if (errno == EMFILE || errno == ENFILE)
    {
        int         save_errno = errno;
 
        ereport(LOG,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("out of file descriptors: %m; release and retry")));
        errno = 0;
        if (ReleaseLruFile())
            goto TryAgain;
        errno = save_errno;
    }
 
    return NULL;
}

References allocatedDescs, AllocateDescFile, AllocateDesc::create_subid, AllocateDesc::desc, DO_DB, elog, ereport, errcode(), errmsg(), ERROR, fb(), AllocateDesc::file, GetCurrentSubTransactionId(), AllocateDesc::kind, LOG, maxAllocatedDescs, mode, name, numAllocatedDescs, ReleaseLruFile(), ReleaseLruFiles(), and reserveAllocatedDesc().

Referenced by AlterSystemSetConfigFile(), apw_dump_now(), apw_load_buffers(), BeginCopyFrom(), BeginCopyTo(), checkControlFile(), do_pg_backup_stop(), entry_reset(), existsTimeLineHistory(), ExportSnapshot(), gc_qtexts(), GetHugePageSize(), ImportSnapshot(), load_dh_file(), load_relcache_init_file(), open_auth_file(), parse_extension_control_file(), ParseConfigFile(), ParseTzFile(), pg_current_logfile(), pg_promote(), pgss_shmem_shutdown(), pgss_shmem_startup(), pgstat_read_statsfile(), pgstat_write_statsfile(), read_backup_label(), read_binary_file(), read_tablespace_map(), read_whole_file(), readTimeLineHistory(), test_custom_stats_var_from_serialized_data(), test_custom_stats_var_to_serialized_data(), tsearch_readline_begin(), ValidatePgVersion(), write_relcache_init_file(), XLogArchiveForceDone(), and XLogArchiveNotify().

AllocateVfd()

static File AllocateVfd ( void  )

static

Definition at line 1401 of file fd.c.

{
    Index       i;
    File        file;
 
    DO_DB(elog(LOG, "AllocateVfd. Size %zu", SizeVfdCache));
 
    Assert(SizeVfdCache > 0);   /* InitFileAccess not called? */
 
    if (VfdCache[0].nextFree == 0)
    {
        /*
         * The free list is empty so it is time to increase the size of the
         * array.  We choose to double it each time this happens. However,
         * there's not much point in starting *real* small.
         */
        Size        newCacheSize = SizeVfdCache * 2;
        Vfd        *newVfdCache;
 
        if (newCacheSize < 32)
            newCacheSize = 32;
 
        /*
         * Be careful not to clobber VfdCache ptr if realloc fails.
         */
        newVfdCache = (Vfd *) realloc(VfdCache, sizeof(Vfd) * newCacheSize);
        if (newVfdCache == NULL)
            ereport(ERROR,
                    (errcode(ERRCODE_OUT_OF_MEMORY),
                     errmsg("out of memory")));
        VfdCache = newVfdCache;
 
        /*
         * Initialize the new entries and link them into the free list.
         */
        for (i = SizeVfdCache; i < newCacheSize; i++)
        {
            MemSet(&(VfdCache[i]), 0, sizeof(Vfd));
            VfdCache[i].nextFree = i + 1;
            VfdCache[i].fd = VFD_CLOSED;
        }
        VfdCache[newCacheSize - 1].nextFree = 0;
        VfdCache[0].nextFree = SizeVfdCache;
 
        /*
         * Record the new size
         */
        SizeVfdCache = newCacheSize;
    }
 
    file = VfdCache[0].nextFree;
 
    VfdCache[0].nextFree = VfdCache[file].nextFree;
 
    return file;
}

References Assert, DO_DB, elog, ereport, errcode(), errmsg(), ERROR, fb(), vfd::fd, i, LOG, MemSet, vfd::nextFree, realloc, SizeVfdCache, VFD_CLOSED, and VfdCache.

Referenced by PathNameOpenFilePerm().

assign_debug_io_direct()

void assign_debug_io_direct	(	const char *	newval,
		void *	extra
	)

Definition at line 4078 of file fd.c.

{
    int        *flags = (int *) extra;
 
    io_direct_flags = *flags;
}

References io_direct_flags.

AtEOSubXact_Files()

void AtEOSubXact_Files	(	bool	isCommit,
		SubTransactionId	mySubid,
		SubTransactionId	parentSubid
	)

Definition at line 3180 of file fd.c.

{
    Index       i;
 
    for (i = 0; i < numAllocatedDescs; i++)
    {
        if (allocatedDescs[i].create_subid == mySubid)
        {
            if (isCommit)
                allocatedDescs[i].create_subid = parentSubid;
            else
            {
                /* have to recheck the item after FreeDesc (ugly) */
                FreeDesc(&allocatedDescs[i--]);
            }
        }
    }
}

References allocatedDescs, AllocateDesc::create_subid, fb(), FreeDesc(), i, and numAllocatedDescs.

Referenced by AbortSubTransaction(), and CommitSubTransaction().

AtEOXact_Files()

void AtEOXact_Files

(

bool

isCommit

)

Definition at line 3213 of file fd.c.

{
    CleanupTempFiles(isCommit, false);
    tempTableSpaces = NULL;
    numTempTableSpaces = -1;
}

References CleanupTempFiles(), fb(), numTempTableSpaces, and tempTableSpaces.

Referenced by AbortTransaction(), AutoVacLauncherMain(), BackgroundWriterMain(), CheckpointerMain(), CommitTransaction(), pgarch_archiveXlog(), PrepareTransaction(), WalSummarizerMain(), and WalWriterMain().

BasicOpenFile()

int BasicOpenFile	(	const char *	fileName,
		int	fileFlags
	)

Definition at line 1089 of file fd.c.

{
    return BasicOpenFilePerm(fileName, fileFlags, pg_file_create_mode);
}

References BasicOpenFilePerm(), and pg_file_create_mode.

Referenced by AlterSystemSetConfigFile(), ReadControlFile(), update_controlfile(), wal_segment_open(), WalSndSegmentOpen(), WriteControlFile(), XLogFileInit(), XLogFileInitInternal(), XLogFileOpen(), and XLogFileRead().

BasicOpenFilePerm()

int BasicOpenFilePerm	(	const char *	fileName,
		int	fileFlags,
		mode_t	fileMode
	)

Definition at line 1111 of file fd.c.

{
    int         fd;
 
tryAgain:
#ifdef PG_O_DIRECT_USE_F_NOCACHE
    fd = open(fileName, fileFlags & ~PG_O_DIRECT, fileMode);
#else
    fd = open(fileName, fileFlags, fileMode);
#endif
 
    if (fd >= 0)
    {
#ifdef PG_O_DIRECT_USE_F_NOCACHE
        if (fileFlags & PG_O_DIRECT)
        {
            if (fcntl(fd, F_NOCACHE, 1) < 0)
            {
                int         save_errno = errno;
 
                close(fd);
                errno = save_errno;
                return -1;
            }
        }
#endif
 
        return fd;              /* success! */
    }
 
    if (errno == EMFILE || errno == ENFILE)
    {
        int         save_errno = errno;
 
        ereport(LOG,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("out of file descriptors: %m; release and retry")));
        errno = 0;
        if (ReleaseLruFile())
            goto tryAgain;
        errno = save_errno;
    }
 
    return -1;                  /* failure */
}

References close, ereport, errcode(), errmsg(), fb(), fd(), LOG, PG_O_DIRECT, and ReleaseLruFile().

Referenced by BasicOpenFile(), LruInsert(), OpenTransientFilePerm(), PathNameOpenFilePerm(), and readRecoverySignalFile().

BeforeShmemExit_Files()

static void BeforeShmemExit_Files ( int  code, Datum  arg  )

static

Definition at line 3227 of file fd.c.

{
    CleanupTempFiles(false, true);
 
    /* prevent further temp files from being created */
#ifdef USE_ASSERT_CHECKING
    temporary_files_allowed = false;
#endif
}

References CleanupTempFiles(), and fb().

Referenced by InitTemporaryFileAccess().

check_debug_io_direct()

bool check_debug_io_direct	(	char **	newval,
		void **	extra,
		GucSource	source
	)

Definition at line 3991 of file fd.c.

{
    bool        result = true;
    int         flags;
 
#if PG_O_DIRECT == 0
    if (strcmp(*newval, "") != 0)
    {
        GUC_check_errdetail("\"%s\" is not supported on this platform.",
                            "debug_io_direct");
        result = false;
    }
    flags = 0;
#else
    List       *elemlist;
    ListCell   *l;
    char       *rawstring;
 
    /* Need a modifiable copy of string */
    rawstring = pstrdup(*newval);
 
    if (!SplitGUCList(rawstring, ',', &elemlist))
    {
        GUC_check_errdetail("Invalid list syntax in parameter \"%s\".",
                            "debug_io_direct");
        pfree(rawstring);
        list_free(elemlist);
        return false;
    }
 
    flags = 0;
    foreach(l, elemlist)
    {
        char       *item = (char *) lfirst(l);
 
        if (pg_strcasecmp(item, "data") == 0)
            flags |= IO_DIRECT_DATA;
        else if (pg_strcasecmp(item, "wal") == 0)
            flags |= IO_DIRECT_WAL;
        else if (pg_strcasecmp(item, "wal_init") == 0)
            flags |= IO_DIRECT_WAL_INIT;
        else
        {
            GUC_check_errdetail("Invalid option \"%s\".", item);
            result = false;
            break;
        }
    }
 
    /*
     * It's possible to configure block sizes smaller than our assumed I/O
     * alignment size, which could result in invalid I/O requests.
     */
#if XLOG_BLCKSZ < PG_IO_ALIGN_SIZE
    if (result && (flags & (IO_DIRECT_WAL | IO_DIRECT_WAL_INIT)))
    {
        GUC_check_errdetail("\"%s\" is not supported for WAL because %s is too small.",
                            "debug_io_direct", "XLOG_BLCKSZ");
        result = false;
    }
#endif
#if BLCKSZ < PG_IO_ALIGN_SIZE
    if (result && (flags & IO_DIRECT_DATA))
    {
        GUC_check_errdetail("\"%s\" is not supported for data because %s is too small.",
                            "debug_io_direct", "BLCKSZ");
        result = false;
    }
#endif
 
    pfree(rawstring);
    list_free(elemlist);
#endif
 
    if (!result)
        return result;
 
    /* Save the flags in *extra, for use by assign_debug_io_direct */
    *extra = guc_malloc(LOG, sizeof(int));
    if (!*extra)
        return false;
    *((int *) *extra) = flags;
 
    return result;
}

References fb(), GUC_check_errdetail, guc_malloc(), IO_DIRECT_DATA, IO_DIRECT_WAL, IO_DIRECT_WAL_INIT, lfirst, list_free(), LOG, newval, pfree(), pg_strcasecmp(), pstrdup(), and SplitGUCList().

CleanupTempFiles()

static void CleanupTempFiles ( bool  isCommit, bool  isProcExit  )

static

Definition at line 3250 of file fd.c.

{
    Index       i;
 
    /*
     * Careful here: at proc_exit we need extra cleanup, not just
     * xact_temporary files.
     */
    if (isProcExit || have_xact_temporary_files)
    {
        Assert(FileIsNotOpen(0));   /* Make sure ring not corrupted */
        for (i = 1; i < SizeVfdCache; i++)
        {
            unsigned short fdstate = VfdCache[i].fdstate;
 
            if (((fdstate & FD_DELETE_AT_CLOSE) || (fdstate & FD_CLOSE_AT_EOXACT)) &&
                VfdCache[i].fileName != NULL)
            {
                /*
                 * If we're in the process of exiting a backend process, close
                 * all temporary files. Otherwise, only close temporary files
                 * local to the current transaction. They should be closed by
                 * the ResourceOwner mechanism already, so this is just a
                 * debugging cross-check.
                 */
                if (isProcExit)
                    FileClose(i);
                else if (fdstate & FD_CLOSE_AT_EOXACT)
                {
                    elog(WARNING,
                         "temporary file %s not closed at end-of-transaction",
                         VfdCache[i].fileName);
                    FileClose(i);
                }
            }
        }
 
        have_xact_temporary_files = false;
    }
 
    /* Complain if any allocated files remain open at commit. */
    if (isCommit && numAllocatedDescs > 0)
        elog(WARNING, "%d temporary files and directories not closed at end-of-transaction",
             numAllocatedDescs);
 
    /* Clean up "allocated" stdio files, dirs and fds. */
    while (numAllocatedDescs > 0)
        FreeDesc(&allocatedDescs[0]);
}

References allocatedDescs, Assert, elog, fb(), FD_CLOSE_AT_EOXACT, FD_DELETE_AT_CLOSE, vfd::fdstate, FileClose(), FileIsNotOpen, FreeDesc(), have_xact_temporary_files, i, numAllocatedDescs, SizeVfdCache, VfdCache, and WARNING.

Referenced by AtEOXact_Files(), and BeforeShmemExit_Files().

closeAllVfds()

void closeAllVfds

(

void

)

Definition at line 3067 of file fd.c.

{
    Index       i;
 
    if (SizeVfdCache > 0)
    {
        Assert(FileIsNotOpen(0));   /* Make sure ring not corrupted */
        for (i = 1; i < SizeVfdCache; i++)
        {
            if (!FileIsNotOpen(i))
                LruDelete(i);
        }
    }
}

References Assert, FileIsNotOpen, i, LruDelete(), and SizeVfdCache.

Referenced by standard_ProcessUtility().

ClosePipeStream()

int ClosePipeStream

(

FILE *

file

)

Definition at line 3038 of file fd.c.

{
    int         i;
 
    DO_DB(elog(LOG, "ClosePipeStream: Allocated %d", numAllocatedDescs));
 
    /* Remove file from list of allocated files, if it's present */
    for (i = numAllocatedDescs; --i >= 0;)
    {
        AllocateDesc *desc = &allocatedDescs[i];
 
        if (desc->kind == AllocateDescPipe && desc->desc.file == file)
            return FreeDesc(desc);
    }
 
    /* Only get here if someone passes us a file not in allocatedDescs */
    elog(WARNING, "file passed to ClosePipeStream was not obtained from OpenPipeStream");
 
    return pclose(file);
}

References allocatedDescs, AllocateDescPipe, AllocateDesc::desc, DO_DB, elog, fb(), AllocateDesc::file, FreeDesc(), i, AllocateDesc::kind, LOG, numAllocatedDescs, and WARNING.

Referenced by ClosePipeFromProgram(), ClosePipeToProgram(), pg_import_system_collations(), run_ssl_passphrase_command(), and shell_finish_command().

CloseTransientFile()

int CloseTransientFile

(

int

fd

)

Definition at line 2854 of file fd.c.

{
    int         i;
 
    DO_DB(elog(LOG, "CloseTransientFile: Allocated %d", numAllocatedDescs));
 
    /* Remove fd from list of allocated files, if it's present */
    for (i = numAllocatedDescs; --i >= 0;)
    {
        AllocateDesc *desc = &allocatedDescs[i];
 
        if (desc->kind == AllocateDescRawFD && desc->desc.fd == fd)
            return FreeDesc(desc);
    }
 
    /* Only get here if someone passes us a file not in allocatedDescs */
    elog(WARNING, "fd passed to CloseTransientFile was not obtained from OpenTransientFile");
 
    pgaio_closing_fd(fd);
 
    return close(fd);
}

References allocatedDescs, AllocateDescRawFD, close, AllocateDesc::desc, DO_DB, elog, AllocateDesc::fd, fd(), FreeDesc(), i, AllocateDesc::kind, LOG, numAllocatedDescs, pgaio_closing_fd(), and WARNING.

Referenced by ApplyLogicalMappingFile(), be_lo_export(), CheckPointLogicalRewriteHeap(), CheckPointReplicationOrigin(), clone_file(), compare_files(), copy_file(), CreateDirAndVersionFile(), dsm_impl_mmap(), durable_rename(), fsync_fname_ext(), get_controlfile_by_exact_path(), heap_xlog_logical_rewrite(), lo_import_internal(), perform_base_backup(), pg_truncate(), qtext_load_file(), qtext_store(), read_relmap_file(), ReadTwoPhaseFile(), RecreateTwoPhaseFile(), ReorderBufferSerializeChange(), ReorderBufferSerializeTXN(), RestoreSlotFromDisk(), SaveSlotToPath(), sendFile(), SendTimeLineHistory(), SimpleLruDoesPhysicalPageExist(), SimpleLruWriteAll(), SlruInternalWritePage(), SlruPhysicalReadPage(), SlruPhysicalWritePage(), SlruSyncFileTag(), SnapBuildRestoreContents(), SnapBuildRestoreSnapshot(), SnapBuildSerialize(), StartupReplicationOrigin(), write_relmap_file(), writeTimeLineHistory(), writeTimeLineHistoryFile(), and XLogFileCopy().

count_usable_fds()

static void count_usable_fds ( int  max_to_probe, int *  usable_fds, int *  already_open  )

static

Definition at line 964 of file fd.c.

{
    int        *fd;
    int         size;
    int         used = 0;
    int         highestfd = 0;
    int         j;
 
#ifdef HAVE_GETRLIMIT
    struct rlimit rlim;
    int         getrlimit_status;
#endif
 
    size = 1024;
    fd = (int *) palloc(size * sizeof(int));
 
#ifdef HAVE_GETRLIMIT
    getrlimit_status = getrlimit(RLIMIT_NOFILE, &rlim);
    if (getrlimit_status != 0)
        ereport(WARNING, (errmsg("getrlimit failed: %m")));
#endif                          /* HAVE_GETRLIMIT */
 
    /* dup until failure or probe limit reached */
    for (;;)
    {
        int         thisfd;
 
#ifdef HAVE_GETRLIMIT
 
        /*
         * don't go beyond RLIMIT_NOFILE; causes irritating kernel logs on
         * some platforms
         */
        if (getrlimit_status == 0 && highestfd >= rlim.rlim_cur - 1)
            break;
#endif
 
        thisfd = dup(2);
        if (thisfd < 0)
        {
            /* Expect EMFILE or ENFILE, else it's fishy */
            if (errno != EMFILE && errno != ENFILE)
                elog(WARNING, "duplicating stderr file descriptor failed after %d successes: %m", used);
            break;
        }
 
        if (used >= size)
        {
            size *= 2;
            fd = (int *) repalloc(fd, size * sizeof(int));
        }
        fd[used++] = thisfd;
 
        if (highestfd < thisfd)
            highestfd = thisfd;
 
        if (used >= max_to_probe)
            break;
    }
 
    /* release the files we opened */
    for (j = 0; j < used; j++)
        close(fd[j]);
 
    pfree(fd);
 
    /*
     * Return results.  usable_fds is just the number of successful dups. We
     * assume that the system limit is highestfd+1 (remember 0 is a legal FD
     * number) and so already_open is highestfd+1 - usable_fds.
     */
    *usable_fds = used;
    *already_open = highestfd + 1 - used;
}

References close, elog, ereport, errmsg(), fb(), fd(), j, palloc(), pfree(), repalloc(), and WARNING.

Referenced by set_max_safe_fds().

data_sync_elevel()

int data_sync_elevel

(

int

elevel

)

Definition at line 3985 of file fd.c.

{
    return data_sync_retry ? elevel : PANIC;
}

References data_sync_retry, and PANIC.

Referenced by CheckPointLogicalRewriteHeap(), CreateDirAndVersionFile(), FileClose(), fsync_fname(), heap_xlog_logical_rewrite(), logical_end_heap_rewrite(), LruDelete(), mdimmedsync(), pg_flush_data(), ProcessSyncRequests(), register_dirty_segment(), SlruReportIOError(), writeTimeLineHistory(), writeTimeLineHistoryFile(), and XLogFileCopy().

datadir_fsync_fname()

static void datadir_fsync_fname ( const char *  fname, bool  isdir, int  elevel  )

static

Definition at line 3808 of file fd.c.

{
    ereport_startup_progress("syncing data directory (fsync), elapsed time: %ld.%02d s, current path: %s",
                             fname);
 
    /*
     * We want to silently ignoring errors about unreadable files.  Pass that
     * desire on to fsync_fname_ext().
     */
    fsync_fname_ext(fname, isdir, true, elevel);
}

References ereport_startup_progress, fb(), and fsync_fname_ext().

Referenced by SyncDataDirectory().

Delete()

static void Delete ( File  file )

static

Definition at line 1253 of file fd.c.

{
    Vfd        *vfdP;
 
    Assert(file != 0);
 
    DO_DB(elog(LOG, "Delete %d (%s)",
               file, VfdCache[file].fileName));
    DO_DB(_dump_lru());
 
    vfdP = &VfdCache[file];
 
    VfdCache[vfdP->lruLessRecently].lruMoreRecently = vfdP->lruMoreRecently;
    VfdCache[vfdP->lruMoreRecently].lruLessRecently = vfdP->lruLessRecently;
 
    DO_DB(_dump_lru());
}

References Assert, DO_DB, elog, fb(), LOG, vfd::lruLessRecently, vfd::lruMoreRecently, and VfdCache.

Referenced by FileAccess(), FileClose(), and LruDelete().

durable_rename()

int durable_rename	(	const char *	oldfile,
		const char *	newfile,
		int	elevel
	)

Definition at line 782 of file fd.c.

{
    int         fd;
 
    /*
     * First fsync the old and target path (if it exists), to ensure that they
     * are properly persistent on disk. Syncing the target file is not
     * strictly necessary, but it makes it easier to reason about crashes;
     * because it's then guaranteed that either source or target file exists
     * after a crash.
     */
    if (fsync_fname_ext(oldfile, false, false, elevel) != 0)
        return -1;
 
    fd = OpenTransientFile(newfile, PG_BINARY | O_RDWR);
    if (fd < 0)
    {
        if (errno != ENOENT)
        {
            ereport(elevel,
                    (errcode_for_file_access(),
                     errmsg("could not open file \"%s\": %m", newfile)));
            return -1;
        }
    }
    else
    {
        if (pg_fsync(fd) != 0)
        {
            int         save_errno;
 
            /* close file upon error, might not be in transaction context */
            save_errno = errno;
            CloseTransientFile(fd);
            errno = save_errno;
 
            ereport(elevel,
                    (errcode_for_file_access(),
                     errmsg("could not fsync file \"%s\": %m", newfile)));
            return -1;
        }
 
        if (CloseTransientFile(fd) != 0)
        {
            ereport(elevel,
                    (errcode_for_file_access(),
                     errmsg("could not close file \"%s\": %m", newfile)));
            return -1;
        }
    }
 
    /* Time to do the real deal... */
    if (rename(oldfile, newfile) < 0)
    {
        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not rename file \"%s\" to \"%s\": %m",
                        oldfile, newfile)));
        return -1;
    }
 
    /*
     * To guarantee renaming the file is persistent, fsync the file with its
     * new name, and its containing directory.
     */
    if (fsync_fname_ext(newfile, false, false, elevel) != 0)
        return -1;
 
    if (fsync_parent_path(newfile, elevel) != 0)
        return -1;
 
    return 0;
}

References CloseTransientFile(), ereport, errcode_for_file_access(), errmsg(), fb(), fd(), fsync_fname_ext(), fsync_parent_path(), OpenTransientFile(), PG_BINARY, and pg_fsync().

Referenced by AlterSystemSetConfigFile(), apw_dump_now(), BaseBackup(), basic_archive_file(), bbsink_server_end_manifest(), CheckPointReplicationOrigin(), cleanup_objects_atexit(), CleanupAfterArchiveRecovery(), dir_close(), InitWalRecovery(), InstallXLogFileSegment(), KeepFileRestoredFromArchive(), pgss_shmem_shutdown(), pgstat_write_statsfile(), StartupXLOG(), SummarizeWAL(), write_relmap_file(), writeTimeLineHistory(), writeTimeLineHistoryFile(), and XLogArchiveForceDone().

durable_unlink()

int durable_unlink	(	const char *	fname,
		int	elevel
	)

Definition at line 872 of file fd.c.

{
    if (unlink(fname) < 0)
    {
        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not remove file \"%s\": %m",
                        fname)));
        return -1;
    }
 
    /*
     * To guarantee that the removal of the file is persistent, fsync its
     * parent directory.
     */
    if (fsync_parent_path(fname, elevel) != 0)
        return -1;
 
    return 0;
}

References ereport, errcode_for_file_access(), errmsg(), fb(), and fsync_parent_path().

Referenced by InstallXLogFileSegment(), RemoveXlogFile(), and StartupXLOG().

FileAccess()

static int FileAccess ( File  file )

static

Definition at line 1479 of file fd.c.

{
    int         returnValue;
 
    DO_DB(elog(LOG, "FileAccess %d (%s)",
               file, VfdCache[file].fileName));
 
    /*
     * Is the file open?  If not, open it and put it at the head of the LRU
     * ring (possibly closing the least recently used file to get an FD).
     */
 
    if (FileIsNotOpen(file))
    {
        returnValue = LruInsert(file);
        if (returnValue != 0)
            return returnValue;
    }
    else if (VfdCache[0].lruLessRecently != file)
    {
        /*
         * We now know that the file is open and that it is not the last one
         * accessed, so we need to move it to the head of the Lru ring.
         */
 
        Delete(file);
        Insert(file);
    }
 
    return 0;
}

References Delete(), DO_DB, elog, fb(), FileIsNotOpen, Insert(), LOG, LruInsert(), and VfdCache.

Referenced by FileFallocate(), FileGetRawDesc(), FilePrefetch(), FileReadV(), FileSize(), FileStartReadV(), FileSync(), FileTruncate(), FileWriteback(), FileWriteV(), and FileZero().

FileClose()

void FileClose

(

File

file

)

Definition at line 1965 of file fd.c.

{
    Vfd        *vfdP;
 
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileClose: %d (%s)",
               file, VfdCache[file].fileName));
 
    vfdP = &VfdCache[file];
 
    if (!FileIsNotOpen(file))
    {
        pgaio_closing_fd(vfdP->fd);
 
        /* close the file */
        if (close(vfdP->fd) != 0)
        {
            /*
             * We may need to panic on failure to close non-temporary files;
             * see LruDelete.
             */
            elog(vfdP->fdstate & FD_TEMP_FILE_LIMIT ? LOG : data_sync_elevel(LOG),
                 "could not close file \"%s\": %m", vfdP->fileName);
        }
 
        --nfile;
        vfdP->fd = VFD_CLOSED;
 
        /* remove the file from the lru ring */
        Delete(file);
    }
 
    if (vfdP->fdstate & FD_TEMP_FILE_LIMIT)
    {
        /* Subtract its size from current usage (do first in case of error) */
        temporary_files_size -= vfdP->fileSize;
        vfdP->fileSize = 0;
    }
 
    /*
     * Delete the file if it was temporary, and make a log entry if wanted
     */
    if (vfdP->fdstate & FD_DELETE_AT_CLOSE)
    {
        struct stat filestats;
        int         stat_errno;
 
        /*
         * If we get an error, as could happen within the ereport/elog calls,
         * we'll come right back here during transaction abort.  Reset the
         * flag to ensure that we can't get into an infinite loop.  This code
         * is arranged to ensure that the worst-case consequence is failing to
         * emit log message(s), not failing to attempt the unlink.
         */
        vfdP->fdstate &= ~FD_DELETE_AT_CLOSE;
 
 
        /* first try the stat() */
        if (stat(vfdP->fileName, &filestats))
            stat_errno = errno;
        else
            stat_errno = 0;
 
        /* in any case do the unlink */
        if (unlink(vfdP->fileName))
            ereport(LOG,
                    (errcode_for_file_access(),
                     errmsg("could not delete file \"%s\": %m", vfdP->fileName)));
 
        /* and last report the stat results */
        if (stat_errno == 0)
            ReportTemporaryFileUsage(vfdP->fileName, filestats.st_size);
        else
        {
            errno = stat_errno;
            ereport(LOG,
                    (errcode_for_file_access(),
                     errmsg("could not stat file \"%s\": %m", vfdP->fileName)));
        }
    }
 
    /* Unregister it from the resource owner */
    if (vfdP->resowner)
        ResourceOwnerForgetFile(vfdP->resowner, file);
 
    /*
     * Return the Vfd slot to the free list
     */
    FreeVfd(file);
}

References Assert, close, data_sync_elevel(), Delete(), DO_DB, elog, ereport, errcode_for_file_access(), errmsg(), fb(), FD_DELETE_AT_CLOSE, FD_TEMP_FILE_LIMIT, FileIsNotOpen, FileIsValid, FreeVfd(), LOG, nfile, pgaio_closing_fd(), ReportTemporaryFileUsage(), ResourceOwnerForgetFile(), stat, temporary_files_size, VFD_CLOSED, and VfdCache.

Referenced by bbsink_server_end_archive(), bbsink_server_end_manifest(), BufFileClose(), BufFileTruncateFileSet(), CleanupTempFiles(), logical_end_heap_rewrite(), mdclose(), mdimmedsync(), mdregistersync(), mdsyncfiletag(), mdtruncate(), pg_wal_summary_contents(), PrepareForIncrementalBackup(), ReorderBufferIterTXNFinish(), ReorderBufferRestoreChanges(), ResOwnerReleaseFile(), and SummarizeWAL().

FileFallocate()

int FileFallocate	(	File	file,
		pgoff_t	offset,
		pgoff_t	amount,
		uint32	wait_event_info
	)

Definition at line 2407 of file fd.c.

{
#ifdef HAVE_POSIX_FALLOCATE
    int         returnCode;
 
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileFallocate: %d (%s) " INT64_FORMAT " " INT64_FORMAT,
               file, VfdCache[file].fileName,
               (int64) offset, (int64) amount));
 
    returnCode = FileAccess(file);
    if (returnCode < 0)
        return -1;
 
retry:
    pgstat_report_wait_start(wait_event_info);
    returnCode = posix_fallocate(VfdCache[file].fd, offset, amount);
    pgstat_report_wait_end();
 
    if (returnCode == 0)
        return 0;
    else if (returnCode == EINTR)
        goto retry;
 
    /* for compatibility with %m printing etc */
    errno = returnCode;
 
    /*
     * Return in cases of a "real" failure, if fallocate is not supported,
     * fall through to the FileZero() backed implementation.
     */
    if (returnCode != EINVAL && returnCode != EOPNOTSUPP)
        return -1;
#endif
 
    return FileZero(file, offset, amount, wait_event_info);
}

References Assert, DO_DB, EINTR, elog, EOPNOTSUPP, fb(), fd(), FileAccess(), FileIsValid, FileZero(), INT64_FORMAT, LOG, pgstat_report_wait_end(), pgstat_report_wait_start(), and VfdCache.

Referenced by mdzeroextend().

FileGetRawDesc()

int FileGetRawDesc

(

File

file

)

Definition at line 2515 of file fd.c.

{
    int         returnCode;
 
    returnCode = FileAccess(file);
    if (returnCode < 0)
        return returnCode;
 
    Assert(FileIsValid(file));
    return VfdCache[file].fd;
}

References Assert, fb(), vfd::fd, FileAccess(), FileIsValid, and VfdCache.

Referenced by mdfd().

FileGetRawFlags()

int FileGetRawFlags

(

File

file

)

Definition at line 2531 of file fd.c.

{
    Assert(FileIsValid(file));
    return VfdCache[file].fileFlags;
}

References Assert, vfd::fileFlags, FileIsValid, and VfdCache.

FileGetRawMode()

mode_t FileGetRawMode

(

File

file

)

Definition at line 2541 of file fd.c.

{
    Assert(FileIsValid(file));
    return VfdCache[file].fileMode;
}

References Assert, FileIsValid, vfd::fileMode, and VfdCache.

FilePathName()

char * FilePathName

(

File

file

)

Definition at line 2499 of file fd.c.

{
    Assert(FileIsValid(file));
 
    return VfdCache[file].fileName;
}

References Assert, FileIsValid, vfd::fileName, and VfdCache.

Referenced by _mdnblocks(), bbsink_server_archive_contents(), bbsink_server_end_archive(), bbsink_server_manifest_contents(), BufFileDumpBuffer(), BufFileLoadBuffer(), BufFileSeek(), BufFileSize(), BufFileTruncateFileSet(), mdextend(), mdimmedsync(), mdreadv(), mdstartreadv(), mdsyncfiletag(), mdtruncate(), mdwritev(), mdzeroextend(), pg_wal_summary_contents(), PrepareForIncrementalBackup(), ReadWalSummary(), register_dirty_segment(), and WriteWalSummary().

FilePrefetch()

int FilePrefetch	(	File	file,
		pgoff_t	offset,
		pgoff_t	amount,
		uint32	wait_event_info
	)

Definition at line 2066 of file fd.c.

{
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FilePrefetch: %d (%s) " INT64_FORMAT " " INT64_FORMAT,
               file, VfdCache[file].fileName,
               (int64) offset, (int64) amount));
 
#if defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_WILLNEED)
    {
        int         returnCode;
 
        returnCode = FileAccess(file);
        if (returnCode < 0)
            return returnCode;
 
retry:
        pgstat_report_wait_start(wait_event_info);
        returnCode = posix_fadvise(VfdCache[file].fd, offset, amount,
                                   POSIX_FADV_WILLNEED);
        pgstat_report_wait_end();
 
        if (returnCode == EINTR)
            goto retry;
 
        return returnCode;
    }
#elif defined(__darwin__)
    {
        struct radvisory
        {
            off_t       ra_offset;  /* offset into the file */
            int         ra_count;   /* size of the read     */
        }           ra;
        int         returnCode;
 
        returnCode = FileAccess(file);
        if (returnCode < 0)
            return returnCode;
 
        ra.ra_offset = offset;
        ra.ra_count = amount;
        pgstat_report_wait_start(wait_event_info);
        returnCode = fcntl(VfdCache[file].fd, F_RDADVISE, &ra);
        pgstat_report_wait_end();
        if (returnCode != -1)
            return 0;
        else
            return errno;
    }
#else
    return 0;
#endif
}

References Assert, DO_DB, EINTR, elog, fb(), fd(), FileAccess(), FileIsValid, INT64_FORMAT, LOG, pgstat_report_wait_end(), pgstat_report_wait_start(), and VfdCache.

Referenced by mdprefetch().

FileReadV()

ssize_t FileReadV	(	File	file,
		const struct iovec *	iov,
		int	iovcnt,
		pgoff_t	offset,
		uint32	wait_event_info
	)

Definition at line 2148 of file fd.c.

{
    ssize_t     returnCode;
    Vfd        *vfdP;
 
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileReadV: %d (%s) " INT64_FORMAT " %d",
               file, VfdCache[file].fileName,
               (int64) offset,
               iovcnt));
 
    returnCode = FileAccess(file);
    if (returnCode < 0)
        return returnCode;
 
    vfdP = &VfdCache[file];
 
retry:
    pgstat_report_wait_start(wait_event_info);
    returnCode = pg_preadv(vfdP->fd, iov, iovcnt, offset);
    pgstat_report_wait_end();
 
    if (returnCode < 0)
    {
        /*
         * Windows may run out of kernel buffers and return "Insufficient
         * system resources" error.  Wait a bit and retry to solve it.
         *
         * It is rumored that EINTR is also possible on some Unix filesystems,
         * in which case immediate retry is indicated.
         */
#ifdef WIN32
        DWORD       error = GetLastError();
 
        switch (error)
        {
            case ERROR_NO_SYSTEM_RESOURCES:
                pg_usleep(1000L);
                errno = EINTR;
                break;
            default:
                _dosmaperr(error);
                break;
        }
#endif
        /* OK to retry if interrupted */
        if (errno == EINTR)
            goto retry;
    }
 
    return returnCode;
}

References _dosmaperr(), Assert, DO_DB, EINTR, elog, error(), fb(), FileAccess(), FileIsValid, INT64_FORMAT, LOG, pg_preadv(), pg_usleep(), pgstat_report_wait_end(), pgstat_report_wait_start(), and VfdCache.

Referenced by FileRead(), and mdreadv().

FileSize()

pgoff_t FileSize

(

File

file

)

Definition at line 2447 of file fd.c.

{
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileSize %d (%s)",
               file, VfdCache[file].fileName));
 
    if (FileIsNotOpen(file))
    {
        if (FileAccess(file) < 0)
            return (pgoff_t) -1;
    }
 
    return lseek(VfdCache[file].fd, 0, SEEK_END);
}

References Assert, DO_DB, elog, fb(), fd(), FileAccess(), FileIsNotOpen, FileIsValid, LOG, and VfdCache.

Referenced by _mdnblocks(), BufFileSeek(), and BufFileSize().

FileStartReadV()

int FileStartReadV	(	PgAioHandle *	ioh,
		File	file,
		int	iovcnt,
		pgoff_t	offset,
		uint32	wait_event_info
	)

Definition at line 2204 of file fd.c.

{
    int         returnCode;
    Vfd        *vfdP;
 
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileStartReadV: %d (%s) " INT64_FORMAT " %d",
               file, VfdCache[file].fileName,
               (int64) offset,
               iovcnt));
 
    returnCode = FileAccess(file);
    if (returnCode < 0)
        return returnCode;
 
    vfdP = &VfdCache[file];
 
    pgaio_io_start_readv(ioh, vfdP->fd, iovcnt, offset);
 
    return 0;
}

References Assert, DO_DB, elog, fb(), FileAccess(), FileIsValid, INT64_FORMAT, LOG, pgaio_io_start_readv(), and VfdCache.

Referenced by mdstartreadv().

FileSync()

int FileSync	(	File	file,
		uint32	wait_event_info
	)

Definition at line 2335 of file fd.c.

{
    int         returnCode;
 
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileSync: %d (%s)",
               file, VfdCache[file].fileName));
 
    returnCode = FileAccess(file);
    if (returnCode < 0)
        return returnCode;
 
    pgstat_report_wait_start(wait_event_info);
    returnCode = pg_fsync(VfdCache[file].fd);
    pgstat_report_wait_end();
 
    return returnCode;
}

References Assert, DO_DB, elog, fb(), fd(), FileAccess(), FileIsValid, LOG, pg_fsync(), pgstat_report_wait_end(), pgstat_report_wait_start(), and VfdCache.

Referenced by bbsink_server_end_archive(), logical_end_heap_rewrite(), mdimmedsync(), mdsyncfiletag(), and register_dirty_segment().

FileTruncate()

int FileTruncate	(	File	file,
		pgoff_t	offset,
		uint32	wait_event_info
	)

Definition at line 2464 of file fd.c.

{
    int         returnCode;
 
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileTruncate %d (%s)",
               file, VfdCache[file].fileName));
 
    returnCode = FileAccess(file);
    if (returnCode < 0)
        return returnCode;
 
    pgstat_report_wait_start(wait_event_info);
    returnCode = pg_ftruncate(VfdCache[file].fd, offset);
    pgstat_report_wait_end();
 
    if (returnCode == 0 && VfdCache[file].fileSize > offset)
    {
        /* adjust our state for truncation of a temp file */
        Assert(VfdCache[file].fdstate & FD_TEMP_FILE_LIMIT);
        temporary_files_size -= VfdCache[file].fileSize - offset;
        VfdCache[file].fileSize = offset;
    }
 
    return returnCode;
}

References Assert, DO_DB, elog, fb(), fd(), FD_TEMP_FILE_LIMIT, FileAccess(), FileIsValid, vfd::fileSize, LOG, pg_ftruncate(), pgstat_report_wait_end(), pgstat_report_wait_start(), temporary_files_size, and VfdCache.

Referenced by BufFileTruncateFileSet(), and mdtruncate().

FileWriteback()

void FileWriteback	(	File	file,
		pgoff_t	offset,
		pgoff_t	nbytes,
		uint32	wait_event_info
	)

Definition at line 2122 of file fd.c.

{
    int         returnCode;
 
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileWriteback: %d (%s) " INT64_FORMAT " " INT64_FORMAT,
               file, VfdCache[file].fileName,
               (int64) offset, (int64) nbytes));
 
    if (nbytes <= 0)
        return;
 
    if (VfdCache[file].fileFlags & PG_O_DIRECT)
        return;
 
    returnCode = FileAccess(file);
    if (returnCode < 0)
        return;
 
    pgstat_report_wait_start(wait_event_info);
    pg_flush_data(VfdCache[file].fd, offset, nbytes);
    pgstat_report_wait_end();
}

References Assert, DO_DB, elog, fb(), fd(), FileAccess(), FileIsValid, INT64_FORMAT, LOG, pg_flush_data(), PG_O_DIRECT, pgstat_report_wait_end(), pgstat_report_wait_start(), and VfdCache.

Referenced by mdwriteback().

FileWriteV()

ssize_t FileWriteV	(	File	file,
		const struct iovec *	iov,
		int	iovcnt,
		pgoff_t	offset,
		uint32	wait_event_info
	)

Definition at line 2230 of file fd.c.

{
    ssize_t     returnCode;
    Vfd        *vfdP;
 
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileWriteV: %d (%s) " INT64_FORMAT " %d",
               file, VfdCache[file].fileName,
               (int64) offset,
               iovcnt));
 
    returnCode = FileAccess(file);
    if (returnCode < 0)
        return returnCode;
 
    vfdP = &VfdCache[file];
 
    /*
     * If enforcing temp_file_limit and it's a temp file, check to see if the
     * write would overrun temp_file_limit, and throw error if so.  Note: it's
     * really a modularity violation to throw error here; we should set errno
     * and return -1.  However, there's no way to report a suitable error
     * message if we do that.  All current callers would just throw error
     * immediately anyway, so this is safe at present.
     */
    if (temp_file_limit >= 0 && (vfdP->fdstate & FD_TEMP_FILE_LIMIT))
    {
        pgoff_t     past_write = offset;
 
        for (int i = 0; i < iovcnt; ++i)
            past_write += iov[i].iov_len;
 
        if (past_write > vfdP->fileSize)
        {
            uint64      newTotal = temporary_files_size;
 
            newTotal += past_write - vfdP->fileSize;
            if (newTotal > (uint64) temp_file_limit * (uint64) 1024)
                ereport(ERROR,
                        (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED),
                         errmsg("temporary file size exceeds \"temp_file_limit\" (%dkB)",
                                temp_file_limit)));
        }
    }
 
retry:
    pgstat_report_wait_start(wait_event_info);
    returnCode = pg_pwritev(vfdP->fd, iov, iovcnt, offset);
    pgstat_report_wait_end();
 
    if (returnCode >= 0)
    {
        /*
         * Some callers expect short writes to set errno, and traditionally we
         * have assumed that they imply disk space shortage.  We don't want to
         * waste CPU cycles adding up the total size here, so we'll just set
         * it for all successful writes in case such a caller determines that
         * the write was short and ereports "%m".
         */
        errno = ENOSPC;
 
        /*
         * Maintain fileSize and temporary_files_size if it's a temp file.
         */
        if (vfdP->fdstate & FD_TEMP_FILE_LIMIT)
        {
            pgoff_t     past_write = offset + returnCode;
 
            if (past_write > vfdP->fileSize)
            {
                temporary_files_size += past_write - vfdP->fileSize;
                vfdP->fileSize = past_write;
            }
        }
    }
    else
    {
        /*
         * See comments in FileReadV()
         */
#ifdef WIN32
        DWORD       error = GetLastError();
 
        switch (error)
        {
            case ERROR_NO_SYSTEM_RESOURCES:
                pg_usleep(1000L);
                errno = EINTR;
                break;
            default:
                _dosmaperr(error);
                break;
        }
#endif
        /* OK to retry if interrupted */
        if (errno == EINTR)
            goto retry;
    }
 
    return returnCode;
}

References _dosmaperr(), Assert, DO_DB, EINTR, elog, ereport, errcode(), errmsg(), ERROR, error(), fb(), FD_TEMP_FILE_LIMIT, FileAccess(), FileIsValid, vfd::fileSize, i, INT64_FORMAT, LOG, pg_pwritev(), pg_usleep(), pgstat_report_wait_end(), pgstat_report_wait_start(), temp_file_limit, temporary_files_size, and VfdCache.

Referenced by FileWrite(), and mdwritev().

FileZero()

int FileZero	(	File	file,
		pgoff_t	offset,
		pgoff_t	amount,
		uint32	wait_event_info
	)

Definition at line 2362 of file fd.c.

{
    int         returnCode;
    ssize_t     written;
 
    Assert(FileIsValid(file));
 
    DO_DB(elog(LOG, "FileZero: %d (%s) " INT64_FORMAT " " INT64_FORMAT,
               file, VfdCache[file].fileName,
               (int64) offset, (int64) amount));
 
    returnCode = FileAccess(file);
    if (returnCode < 0)
        return returnCode;
 
    pgstat_report_wait_start(wait_event_info);
    written = pg_pwrite_zeros(VfdCache[file].fd, amount, offset);
    pgstat_report_wait_end();
 
    if (written < 0)
        return -1;
    else if (written != amount)
    {
        /* if errno is unset, assume problem is no disk space */
        if (errno == 0)
            errno = ENOSPC;
        return -1;
    }
 
    return 0;
}

References Assert, DO_DB, elog, fb(), fd(), FileAccess(), FileIsValid, INT64_FORMAT, LOG, pg_pwrite_zeros(), pgstat_report_wait_end(), pgstat_report_wait_start(), and VfdCache.

Referenced by FileFallocate(), and mdzeroextend().

FreeDesc()

static int FreeDesc ( AllocateDesc *  desc )

static

Definition at line 2786 of file fd.c.

{
    int         result;
 
    /* Close the underlying object */
    switch (desc->kind)
    {
        case AllocateDescFile:
            result = fclose(desc->desc.file);
            break;
        case AllocateDescPipe:
            result = pclose(desc->desc.file);
            break;
        case AllocateDescDir:
            result = closedir(desc->desc.dir);
            break;
        case AllocateDescRawFD:
            pgaio_closing_fd(desc->desc.fd);
            result = close(desc->desc.fd);
            break;
        default:
            elog(ERROR, "AllocateDesc kind not recognized");
            result = 0;         /* keep compiler quiet */
            break;
    }
 
    /* Compact storage in the allocatedDescs array */
    numAllocatedDescs--;
    *desc = allocatedDescs[numAllocatedDescs];
 
    return result;
}

References allocatedDescs, AllocateDescDir, AllocateDescFile, AllocateDescPipe, AllocateDescRawFD, close, closedir(), AllocateDesc::desc, AllocateDesc::dir, elog, ERROR, fb(), AllocateDesc::fd, AllocateDesc::file, AllocateDesc::kind, numAllocatedDescs, and pgaio_closing_fd().

Referenced by AtEOSubXact_Files(), CleanupTempFiles(), ClosePipeStream(), CloseTransientFile(), FreeDir(), and FreeFile().

FreeDir()

int FreeDir

(

DIR *

dir

)

Definition at line 3008 of file fd.c.

{
    int         i;
 
    /* Nothing to do if AllocateDir failed */
    if (dir == NULL)
        return 0;
 
    DO_DB(elog(LOG, "FreeDir: Allocated %d", numAllocatedDescs));
 
    /* Remove dir from list of allocated dirs, if it's present */
    for (i = numAllocatedDescs; --i >= 0;)
    {
        AllocateDesc *desc = &allocatedDescs[i];
 
        if (desc->kind == AllocateDescDir && desc->desc.dir == dir)
            return FreeDesc(desc);
    }
 
    /* Only get here if someone passes us a dir not in allocatedDescs */
    elog(WARNING, "dir passed to FreeDir was not obtained from AllocateDir");
 
    return closedir(dir);
}

References allocatedDescs, AllocateDescDir, closedir(), AllocateDesc::desc, AllocateDesc::dir, DO_DB, elog, fb(), FreeDesc(), i, AllocateDesc::kind, LOG, numAllocatedDescs, and WARNING.

Referenced by calculate_database_size(), calculate_tablespace_size(), CheckPointLogicalRewriteHeap(), CheckPointSnapBuild(), CleanupBackupHistory(), copydir(), db_dir_size(), DeleteAllExportedSnapshotFiles(), destroy_tablespace_directories(), directory_is_empty(), do_pg_backup_start(), dsm_cleanup_for_mmap(), extension_file_exists(), get_ext_ver_list(), GetConfFilesInDir(), getInstallationPaths(), GetWalSummaries(), movedb(), ParseTzFile(), perform_base_backup(), pg_available_extension_versions(), pg_available_extensions(), pg_ls_dir(), pg_ls_dir_files(), pg_tablespace_databases(), pg_tzenumerate_end(), pg_tzenumerate_next(), pgarch_readyXlog(), RelationCacheInitFileRemove(), RelationCacheInitFileRemoveInDir(), RemoveNonParentXlogFiles(), RemoveOldXlogFiles(), RemovePgTempFiles(), RemovePgTempFilesInDir(), RemovePgTempRelationFiles(), RemovePgTempRelationFilesInDbspace(), RemoveTempXlogFiles(), ReorderBufferCleanupSerializedTXNs(), ResetUnloggedRelations(), ResetUnloggedRelationsInDbspaceDir(), ResetUnloggedRelationsInTablespaceDir(), restoreTwoPhaseData(), scan_directory_ci(), sendDir(), SlruScanDirectory(), StartupReorderBuffer(), StartupReplicationSlots(), SyncDataDirectory(), UpdateLogicalMappings(), walkdir(), and XLogGetOldestSegno().

FreeFile()

int FreeFile

(

FILE *

file

)

Definition at line 2826 of file fd.c.

{
    int         i;
 
    DO_DB(elog(LOG, "FreeFile: Allocated %d", numAllocatedDescs));
 
    /* Remove file from list of allocated files, if it's present */
    for (i = numAllocatedDescs; --i >= 0;)
    {
        AllocateDesc *desc = &allocatedDescs[i];
 
        if (desc->kind == AllocateDescFile && desc->desc.file == file)
            return FreeDesc(desc);
    }
 
    /* Only get here if someone passes us a file not in allocatedDescs */
    elog(WARNING, "file passed to FreeFile was not obtained from AllocateFile");
 
    return fclose(file);
}

References allocatedDescs, AllocateDescFile, AllocateDesc::desc, DO_DB, elog, fb(), AllocateDesc::file, FreeDesc(), i, AllocateDesc::kind, LOG, numAllocatedDescs, and WARNING.

Referenced by AlterSystemSetConfigFile(), apw_dump_now(), apw_load_buffers(), checkControlFile(), do_pg_backup_stop(), EndCopy(), EndCopyFrom(), entry_reset(), existsTimeLineHistory(), ExportSnapshot(), free_auth_file(), gc_qtexts(), GetHugePageSize(), ImportSnapshot(), load_dh_file(), load_relcache_init_file(), parse_extension_control_file(), ParseConfigFile(), ParseTzFile(), pg_current_logfile(), pg_promote(), pgss_shmem_shutdown(), pgss_shmem_startup(), pgstat_read_statsfile(), pgstat_write_statsfile(), read_backup_label(), read_binary_file(), read_tablespace_map(), read_whole_file(), readTimeLineHistory(), test_custom_stats_var_finish(), tsearch_readline_end(), ValidatePgVersion(), write_relcache_init_file(), XLogArchiveForceDone(), and XLogArchiveNotify().

FreeVfd()

static void FreeVfd ( File  file )

static

Definition at line 1459 of file fd.c.

{
    Vfd        *vfdP = &VfdCache[file];
 
    DO_DB(elog(LOG, "FreeVfd: %d (%s)",
               file, vfdP->fileName ? vfdP->fileName : ""));
 
    if (vfdP->fileName != NULL)
    {
        free(vfdP->fileName);
        vfdP->fileName = NULL;
    }
    vfdP->fdstate = 0x0;
 
    vfdP->nextFree = VfdCache[0].nextFree;
    VfdCache[0].nextFree = file;
}

References DO_DB, elog, fb(), free, LOG, vfd::nextFree, and VfdCache.

Referenced by FileClose(), and PathNameOpenFilePerm().

fsync_fname()

void fsync_fname	(	const char *	fname,
		bool	isdir
	)

Definition at line 756 of file fd.c.

{
    fsync_fname_ext(fname, isdir, false, data_sync_elevel(ERROR));
}

References data_sync_elevel(), ERROR, fb(), and fsync_fname_ext().

Referenced by _CloseArchive(), _CloseArchive(), basic_archive_file(), CheckPointLogicalRewriteHeap(), CheckPointTwoPhase(), copydir(), CreateDirAndVersionFile(), CreateSlotOnDisk(), dir_close(), dir_finish(), dir_open_for_write(), main(), ReplicationSlotDropPtr(), ResetUnloggedRelationsInDbspaceDir(), RestoreSlotFromDisk(), SaveSlotToPath(), SimpleLruWriteAll(), SnapBuildRestoreSnapshot(), SnapBuildSerialize(), StartupReplicationSlots(), swap_catalog_files(), sync_queue_sync_all(), and tar_finish().

fsync_fname_ext()

int fsync_fname_ext	(	const char *	fname,
		bool	isdir,
		bool	ignore_perm,
		int	elevel
	)

Definition at line 3846 of file fd.c.

{
    int         fd;
    int         flags;
    int         returncode;
 
    /*
     * Some OSs require directories to be opened read-only whereas other
     * systems don't allow us to fsync files opened read-only; so we need both
     * cases here.  Using O_RDWR will cause us to fail to fsync files that are
     * not writable by our userid, but we assume that's OK.
     */
    flags = PG_BINARY;
    if (!isdir)
        flags |= O_RDWR;
    else
        flags |= O_RDONLY;
 
    fd = OpenTransientFile(fname, flags);
 
    /*
     * Some OSs don't allow us to open directories at all (Windows returns
     * EACCES), just ignore the error in that case.  If desired also silently
     * ignoring errors about unreadable files. Log others.
     */
    if (fd < 0 && isdir && (errno == EISDIR || errno == EACCES))
        return 0;
    else if (fd < 0 && ignore_perm && errno == EACCES)
        return 0;
    else if (fd < 0)
    {
        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not open file \"%s\": %m", fname)));
        return -1;
    }
 
    returncode = pg_fsync(fd);
 
    /*
     * Some OSes don't allow us to fsync directories at all, so we can ignore
     * those errors. Anything else needs to be logged.
     */
    if (returncode != 0 && !(isdir && (errno == EBADF || errno == EINVAL)))
    {
        int         save_errno;
 
        /* close file upon error, might not be in transaction context */
        save_errno = errno;
        (void) CloseTransientFile(fd);
        errno = save_errno;
 
        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not fsync file \"%s\": %m", fname)));
        return -1;
    }
 
    if (CloseTransientFile(fd) != 0)
    {
        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not close file \"%s\": %m", fname)));
        return -1;
    }
 
    return 0;
}

References CloseTransientFile(), ereport, errcode_for_file_access(), errmsg(), fb(), fd(), OpenTransientFile(), PG_BINARY, and pg_fsync().

Referenced by datadir_fsync_fname(), durable_rename(), fsync_fname(), and fsync_parent_path().

fsync_parent_path()

static int fsync_parent_path ( const char *  fname, int  elevel  )

static

Definition at line 3922 of file fd.c.

{
    char        parentpath[MAXPGPATH];
 
    strlcpy(parentpath, fname, MAXPGPATH);
    get_parent_directory(parentpath);
 
    /*
     * get_parent_directory() returns an empty string if the input argument is
     * just a file name (see comments in path.c), so handle that as being the
     * current directory.
     */
    if (strlen(parentpath) == 0)
        strlcpy(parentpath, ".", MAXPGPATH);
 
    if (fsync_fname_ext(parentpath, true, false, elevel) != 0)
        return -1;
 
    return 0;
}

References fb(), fsync_fname_ext(), get_parent_directory(), MAXPGPATH, and strlcpy().

Referenced by dir_close(), dir_open_for_write(), durable_rename(), durable_unlink(), swap_catalog_files(), and tar_finish().

GetNextTempTableSpace()

Oid GetNextTempTableSpace

(

void

)

Definition at line 3158 of file fd.c.

{
    if (numTempTableSpaces > 0)
    {
        /* Advance nextTempTableSpace counter with wraparound */
        if (++nextTempTableSpace >= numTempTableSpaces)
            nextTempTableSpace = 0;
        return tempTableSpaces[nextTempTableSpace];
    }
    return InvalidOid;
}

References InvalidOid, nextTempTableSpace, numTempTableSpaces, and tempTableSpaces.

Referenced by GetDefaultTablespace(), and OpenTemporaryFile().

GetTempTablespaces()

int GetTempTablespaces	(	Oid *	tableSpaces,
		int	numSpaces
	)

Definition at line 3140 of file fd.c.

{
    int         i;
 
    Assert(TempTablespacesAreSet());
    for (i = 0; i < numTempTableSpaces && i < numSpaces; ++i)
        tableSpaces[i] = tempTableSpaces[i];
 
    return i;
}

References Assert, fb(), i, numTempTableSpaces, tempTableSpaces, and TempTablespacesAreSet().

Referenced by FileSetInit().

InitFileAccess()

void InitFileAccess

(

void

)

Definition at line 903 of file fd.c.

{
    Assert(SizeVfdCache == 0);  /* call me only once */
 
    /* initialize cache header entry */
    VfdCache = (Vfd *) malloc(sizeof(Vfd));
    if (VfdCache == NULL)
        ereport(FATAL,
                (errcode(ERRCODE_OUT_OF_MEMORY),
                 errmsg("out of memory")));
 
    MemSet(&(VfdCache[0]), 0, sizeof(Vfd));
    VfdCache->fd = VFD_CLOSED;
 
    SizeVfdCache = 1;
}

References Assert, ereport, errcode(), errmsg(), FATAL, fb(), vfd::fd, malloc, MemSet, SizeVfdCache, VFD_CLOSED, and VfdCache.

Referenced by BaseInit().

InitTemporaryFileAccess()

void InitTemporaryFileAccess

(

void

)

Definition at line 933 of file fd.c.

{
    Assert(SizeVfdCache != 0);  /* InitFileAccess() needs to have run */
    Assert(!temporary_files_allowed);   /* call me only once */
 
    /*
     * Register before-shmem-exit hook to ensure temp files are dropped while
     * we can still report stats.
     */
    before_shmem_exit(BeforeShmemExit_Files, 0);
 
#ifdef USE_ASSERT_CHECKING
    temporary_files_allowed = true;
#endif
}

References Assert, before_shmem_exit(), BeforeShmemExit_Files(), fb(), and SizeVfdCache.

Referenced by BaseInit().

Insert()

static void Insert ( File  file )

static

Definition at line 1300 of file fd.c.

{
    Vfd        *vfdP;
 
    Assert(file != 0);
 
    DO_DB(elog(LOG, "Insert %d (%s)",
               file, VfdCache[file].fileName));
    DO_DB(_dump_lru());
 
    vfdP = &VfdCache[file];
 
    vfdP->lruMoreRecently = 0;
    vfdP->lruLessRecently = VfdCache[0].lruLessRecently;
    VfdCache[0].lruLessRecently = file;
    VfdCache[vfdP->lruLessRecently].lruMoreRecently = file;
 
    DO_DB(_dump_lru());
}

References Assert, DO_DB, elog, fb(), LOG, vfd::lruLessRecently, vfd::lruMoreRecently, and VfdCache.

Referenced by AdvanceXLInsertBuffer(), CreateCheckPoint(), FileAccess(), GetXLogInsertRecPtr(), LruInsert(), PathNameOpenFilePerm(), ReserveXLogInsertLocation(), ReserveXLogSwitch(), StartupXLOG(), UpdateFullPageWrites(), WaitXLogInsertionsToFinish(), XLogInsertRecord(), and XLogWrite().

looks_like_temp_rel_name()

bool looks_like_temp_rel_name

(

const char *

name

)

Definition at line 3498 of file fd.c.

{
    int         pos;
    int         savepos;
 
    /* Must start with "t". */
    if (name[0] != 't')
        return false;
 
    /* Followed by a non-empty string of digits and then an underscore. */
    for (pos = 1; isdigit((unsigned char) name[pos]); ++pos)
        ;
    if (pos == 1 || name[pos] != '_')
        return false;
 
    /* Followed by another nonempty string of digits. */
    for (savepos = ++pos; isdigit((unsigned char) name[pos]); ++pos)
        ;
    if (savepos == pos)
        return false;
 
    /* We might have _forkname or .segment or both. */
    if (name[pos] == '_')
    {
        int         forkchar = forkname_chars(&name[pos + 1], NULL);
 
        if (forkchar <= 0)
            return false;
        pos += forkchar + 1;
    }
    if (name[pos] == '.')
    {
        int         segchar;
 
        for (segchar = 1; isdigit((unsigned char) name[pos + segchar]); ++segchar)
            ;
        if (segchar <= 1)
            return false;
        pos += segchar;
    }
 
    /* Now we should be at the end. */
    if (name[pos] != '\0')
        return false;
    return true;
}

References fb(), forkname_chars(), and name.

Referenced by RemovePgTempRelationFilesInDbspace(), and sendDir().

LruDelete()

static void LruDelete ( File  file )

static

Definition at line 1272 of file fd.c.

{
    Vfd        *vfdP;
 
    Assert(file != 0);
 
    DO_DB(elog(LOG, "LruDelete %d (%s)",
               file, VfdCache[file].fileName));
 
    vfdP = &VfdCache[file];
 
    pgaio_closing_fd(vfdP->fd);
 
    /*
     * Close the file.  We aren't expecting this to fail; if it does, better
     * to leak the FD than to mess up our internal state.
     */
    if (close(vfdP->fd) != 0)
        elog(vfdP->fdstate & FD_TEMP_FILE_LIMIT ? LOG : data_sync_elevel(LOG),
             "could not close file \"%s\": %m", vfdP->fileName);
    vfdP->fd = VFD_CLOSED;
    --nfile;
 
    /* delete the vfd record from the LRU ring */
    Delete(file);
}

References Assert, close, data_sync_elevel(), Delete(), DO_DB, elog, fb(), FD_TEMP_FILE_LIMIT, LOG, nfile, pgaio_closing_fd(), VFD_CLOSED, and VfdCache.

Referenced by closeAllVfds(), and ReleaseLruFile().

LruInsert()

static int LruInsert ( File  file )

static

Definition at line 1322 of file fd.c.

{
    Vfd        *vfdP;
 
    Assert(file != 0);
 
    DO_DB(elog(LOG, "LruInsert %d (%s)",
               file, VfdCache[file].fileName));
 
    vfdP = &VfdCache[file];
 
    if (FileIsNotOpen(file))
    {
        /* Close excess kernel FDs. */
        ReleaseLruFiles();
 
        /*
         * The open could still fail for lack of file descriptors, eg due to
         * overall system file table being full.  So, be prepared to release
         * another FD if necessary...
         */
        vfdP->fd = BasicOpenFilePerm(vfdP->fileName, vfdP->fileFlags,
                                     vfdP->fileMode);
        if (vfdP->fd < 0)
        {
            DO_DB(elog(LOG, "re-open failed: %m"));
            return -1;
        }
        else
        {
            ++nfile;
        }
    }
 
    /*
     * put it at the head of the Lru ring
     */
 
    Insert(file);
 
    return 0;
}

References Assert, BasicOpenFilePerm(), DO_DB, elog, fb(), FileIsNotOpen, Insert(), LOG, nfile, ReleaseLruFiles(), and VfdCache.

Referenced by FileAccess().

MakePGDirectory()

int MakePGDirectory

(

const char *

directoryName

)

Definition at line 3962 of file fd.c.

{
    return mkdir(directoryName, pg_dir_create_mode);
}

References fb(), mkdir, and pg_dir_create_mode.

Referenced by bbsink_server_new(), copydir(), create_tablespace_directories(), CreateDirAndVersionFile(), CreateSlotOnDisk(), OpenTemporaryFileInTablespace(), PathNameCreateTemporaryDir(), SysLogger_Start(), SysLoggerMain(), TablespaceCreateDbspace(), test_slru_shmem_startup(), and ValidateXLOGDirectoryStructure().

OpenPipeStream()

FILE * OpenPipeStream	(	const char *	command,
		const char *	mode
	)

Definition at line 2730 of file fd.c.

{
    FILE       *file;
    int         save_errno;
 
    DO_DB(elog(LOG, "OpenPipeStream: Allocated %d (%s)",
               numAllocatedDescs, command));
 
    /* Can we allocate another non-virtual FD? */
    if (!reserveAllocatedDesc())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("exceeded maxAllocatedDescs (%d) while trying to execute command \"%s\"",
                        maxAllocatedDescs, command)));
 
    /* Close excess kernel FDs. */
    ReleaseLruFiles();
 
TryAgain:
    fflush(NULL);
    pqsignal(SIGPIPE, SIG_DFL);
    errno = 0;
    file = popen(command, mode);
    save_errno = errno;
    pqsignal(SIGPIPE, SIG_IGN);
    errno = save_errno;
    if (file != NULL)
    {
        AllocateDesc *desc = &allocatedDescs[numAllocatedDescs];
 
        desc->kind = AllocateDescPipe;
        desc->desc.file = file;
        desc->create_subid = GetCurrentSubTransactionId();
        numAllocatedDescs++;
        return desc->desc.file;
    }
 
    if (errno == EMFILE || errno == ENFILE)
    {
        ereport(LOG,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("out of file descriptors: %m; release and retry")));
        if (ReleaseLruFile())
            goto TryAgain;
        errno = save_errno;
    }
 
    return NULL;
}

References allocatedDescs, AllocateDescPipe, AllocateDesc::create_subid, AllocateDesc::desc, DO_DB, elog, ereport, errcode(), errmsg(), ERROR, fb(), AllocateDesc::file, GetCurrentSubTransactionId(), AllocateDesc::kind, LOG, maxAllocatedDescs, mode, numAllocatedDescs, pqsignal, ReleaseLruFile(), ReleaseLruFiles(), reserveAllocatedDesc(), and SIGPIPE.

Referenced by BeginCopyFrom(), BeginCopyTo(), pg_import_system_collations(), run_ssl_passphrase_command(), and shell_run_command().

OpenTemporaryFile()

File OpenTemporaryFile

(

bool

interXact

)

Definition at line 1711 of file fd.c.

{
    File        file = 0;
 
    Assert(temporary_files_allowed);    /* check temp file access is up */
 
    /*
     * Make sure the current resource owner has space for this File before we
     * open it, if we'll be registering it below.
     */
    if (!interXact)
        ResourceOwnerEnlarge(CurrentResourceOwner);
 
    /*
     * If some temp tablespace(s) have been given to us, try to use the next
     * one.  If a given tablespace can't be found, we silently fall back to
     * the database's default tablespace.
     *
     * BUT: if the temp file is slated to outlive the current transaction,
     * force it into the database's default tablespace, so that it will not
     * pose a threat to possible tablespace drop attempts.
     */
    if (numTempTableSpaces > 0 && !interXact)
    {
        Oid         tblspcOid = GetNextTempTableSpace();
 
        if (OidIsValid(tblspcOid))
            file = OpenTemporaryFileInTablespace(tblspcOid, false);
    }
 
    /*
     * If not, or if tablespace is bad, create in database's default
     * tablespace.  MyDatabaseTableSpace should normally be set before we get
     * here, but just in case it isn't, fall back to pg_default tablespace.
     */
    if (file <= 0)
        file = OpenTemporaryFileInTablespace(MyDatabaseTableSpace ?
                                             MyDatabaseTableSpace :
                                             DEFAULTTABLESPACE_OID,
                                             true);
 
    /* Mark it for deletion at close and temporary file size limit */
    VfdCache[file].fdstate |= FD_DELETE_AT_CLOSE | FD_TEMP_FILE_LIMIT;
 
    /* Register it with the current resource owner */
    if (!interXact)
        RegisterTemporaryFile(file);
 
    return file;
}

References Assert, CurrentResourceOwner, fb(), FD_DELETE_AT_CLOSE, FD_TEMP_FILE_LIMIT, vfd::fdstate, GetNextTempTableSpace(), MyDatabaseTableSpace, numTempTableSpaces, OidIsValid, OpenTemporaryFileInTablespace(), RegisterTemporaryFile(), ResourceOwnerEnlarge(), and VfdCache.

Referenced by BufFileCreateTemp(), and extendBufFile().

OpenTemporaryFileInTablespace()

static File OpenTemporaryFileInTablespace ( Oid  tblspcOid, bool  rejectError  )

static

Definition at line 1791 of file fd.c.

{
    char        tempdirpath[MAXPGPATH];
    char        tempfilepath[MAXPGPATH];
    File        file;
 
    TempTablespacePath(tempdirpath, tblspcOid);
 
    /*
     * Generate a tempfile name that should be unique within the current
     * database instance.
     */
    snprintf(tempfilepath, sizeof(tempfilepath), "%s/%s%d.%ld",
             tempdirpath, PG_TEMP_FILE_PREFIX, MyProcPid, tempFileCounter++);
 
    /*
     * Open the file.  Note: we don't use O_EXCL, in case there is an orphaned
     * temp file that can be reused.
     */
    file = PathNameOpenFile(tempfilepath,
                            O_RDWR | O_CREAT | O_TRUNC | PG_BINARY);
    if (file <= 0)
    {
        /*
         * We might need to create the tablespace's tempfile directory, if no
         * one has yet done so.
         *
         * Don't check for an error from MakePGDirectory; it could fail if
         * someone else just did the same thing.  If it doesn't work then
         * we'll bomb out on the second create attempt, instead.
         */
        (void) MakePGDirectory(tempdirpath);
 
        file = PathNameOpenFile(tempfilepath,
                                O_RDWR | O_CREAT | O_TRUNC | PG_BINARY);
        if (file <= 0 && rejectError)
            elog(ERROR, "could not create temporary file \"%s\": %m",
                 tempfilepath);
    }
 
    return file;
}

References elog, ERROR, fb(), MakePGDirectory(), MAXPGPATH, MyProcPid, PathNameOpenFile(), PG_BINARY, PG_TEMP_FILE_PREFIX, snprintf, tempFileCounter, and TempTablespacePath().

Referenced by OpenTemporaryFile().

OpenTransientFile()

int OpenTransientFile	(	const char *	fileName,
		int	fileFlags
	)

Definition at line 2677 of file fd.c.

{
    return OpenTransientFilePerm(fileName, fileFlags, pg_file_create_mode);
}

References OpenTransientFilePerm(), and pg_file_create_mode.

Referenced by ApplyLogicalMappingFile(), CheckPointLogicalRewriteHeap(), CheckPointReplicationOrigin(), clone_file(), compare_files(), copy_file(), CreateDirAndVersionFile(), dsm_impl_mmap(), durable_rename(), fsync_fname_ext(), get_controlfile_by_exact_path(), heap_xlog_logical_rewrite(), lo_import_internal(), perform_base_backup(), pg_truncate(), qtext_load_file(), qtext_store(), read_relmap_file(), ReadTwoPhaseFile(), RecreateTwoPhaseFile(), ReorderBufferSerializeTXN(), RestoreSlotFromDisk(), SaveSlotToPath(), sendFile(), SendTimeLineHistory(), SimpleLruDoesPhysicalPageExist(), SlruPhysicalReadPage(), SlruPhysicalWritePage(), SlruSyncFileTag(), SnapBuildRestoreSnapshot(), SnapBuildSerialize(), StartupReplicationOrigin(), write_relmap_file(), writeTimeLineHistory(), writeTimeLineHistoryFile(), and XLogFileCopy().

OpenTransientFilePerm()

int OpenTransientFilePerm	(	const char *	fileName,
		int	fileFlags,
		mode_t	fileMode
	)

Definition at line 2686 of file fd.c.

{
    int         fd;
 
    DO_DB(elog(LOG, "OpenTransientFile: Allocated %d (%s)",
               numAllocatedDescs, fileName));
 
    /* Can we allocate another non-virtual FD? */
    if (!reserveAllocatedDesc())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("exceeded maxAllocatedDescs (%d) while trying to open file \"%s\"",
                        maxAllocatedDescs, fileName)));
 
    /* Close excess kernel FDs. */
    ReleaseLruFiles();
 
    fd = BasicOpenFilePerm(fileName, fileFlags, fileMode);
 
    if (fd >= 0)
    {
        AllocateDesc *desc = &allocatedDescs[numAllocatedDescs];
 
        desc->kind = AllocateDescRawFD;
        desc->desc.fd = fd;
        desc->create_subid = GetCurrentSubTransactionId();
        numAllocatedDescs++;
 
        return fd;
    }
 
    return -1;                  /* failure */
}

References allocatedDescs, AllocateDescRawFD, BasicOpenFilePerm(), AllocateDesc::create_subid, AllocateDesc::desc, DO_DB, elog, ereport, errcode(), errmsg(), ERROR, fb(), AllocateDesc::fd, fd(), GetCurrentSubTransactionId(), AllocateDesc::kind, LOG, maxAllocatedDescs, numAllocatedDescs, ReleaseLruFiles(), and reserveAllocatedDesc().

Referenced by be_lo_export(), and OpenTransientFile().

PathNameCreateTemporaryDir()

void PathNameCreateTemporaryDir	(	const char *	basedir,
		const char *	directory
	)

Definition at line 1647 of file fd.c.

{
    if (MakePGDirectory(directory) < 0)
    {
        if (errno == EEXIST)
            return;
 
        /*
         * Failed.  Try to create basedir first in case it's missing. Tolerate
         * EEXIST to close a race against another process following the same
         * algorithm.
         */
        if (MakePGDirectory(basedir) < 0 && errno != EEXIST)
            ereport(ERROR,
                    (errcode_for_file_access(),
                     errmsg("cannot create temporary directory \"%s\": %m",
                            basedir)));
 
        /* Try again. */
        if (MakePGDirectory(directory) < 0 && errno != EEXIST)
            ereport(ERROR,
                    (errcode_for_file_access(),
                     errmsg("cannot create temporary subdirectory \"%s\": %m",
                            directory)));
    }
}

References basedir, directory, ereport, errcode_for_file_access(), errmsg(), ERROR, fb(), and MakePGDirectory().

Referenced by FileSetCreate().

PathNameCreateTemporaryFile()

File PathNameCreateTemporaryFile	(	const char *	path,
		bool	error_on_failure
	)

Definition at line 1848 of file fd.c.

{
    File        file;
 
    Assert(temporary_files_allowed);    /* check temp file access is up */
 
    ResourceOwnerEnlarge(CurrentResourceOwner);
 
    /*
     * Open the file.  Note: we don't use O_EXCL, in case there is an orphaned
     * temp file that can be reused.
     */
    file = PathNameOpenFile(path, O_RDWR | O_CREAT | O_TRUNC | PG_BINARY);
    if (file <= 0)
    {
        if (error_on_failure)
            ereport(ERROR,
                    (errcode_for_file_access(),
                     errmsg("could not create temporary file \"%s\": %m",
                            path)));
        else
            return file;
    }
 
    /* Mark it for temp_file_limit accounting. */
    VfdCache[file].fdstate |= FD_TEMP_FILE_LIMIT;
 
    /* Register it for automatic close. */
    RegisterTemporaryFile(file);
 
    return file;
}

References Assert, CurrentResourceOwner, ereport, errcode_for_file_access(), errmsg(), ERROR, fb(), FD_TEMP_FILE_LIMIT, vfd::fdstate, PathNameOpenFile(), PG_BINARY, RegisterTemporaryFile(), ResourceOwnerEnlarge(), and VfdCache.

Referenced by FileSetCreate().

PathNameDeleteTemporaryDir()

void PathNameDeleteTemporaryDir

(

const char *

dirname

)

Definition at line 1678 of file fd.c.

{
    struct stat statbuf;
 
    /* Silently ignore missing directory. */
    if (stat(dirname, &statbuf) != 0 && errno == ENOENT)
        return;
 
    /*
     * Currently, walkdir doesn't offer a way for our passed in function to
     * maintain state.  Perhaps it should, so that we could tell the caller
     * whether this operation succeeded or failed.  Since this operation is
     * used in a cleanup path, we wouldn't actually behave differently: we'll
     * just log failures.
     */
    walkdir(dirname, unlink_if_exists_fname, false, LOG);
}

References fb(), LOG, stat, unlink_if_exists_fname(), and walkdir().

Referenced by FileSetDeleteAll().

PathNameDeleteTemporaryFile()

bool PathNameDeleteTemporaryFile	(	const char *	path,
		bool	error_on_failure
	)

Definition at line 1919 of file fd.c.

{
    struct stat filestats;
    int         stat_errno;
 
    /* Get the final size for pgstat reporting. */
    if (stat(path, &filestats) != 0)
        stat_errno = errno;
    else
        stat_errno = 0;
 
    /*
     * Unlike FileClose's automatic file deletion code, we tolerate
     * non-existence to support BufFileDeleteFileSet which doesn't know how
     * many segments it has to delete until it runs out.
     */
    if (stat_errno == ENOENT)
        return false;
 
    if (unlink(path) < 0)
    {
        if (errno != ENOENT)
            ereport(error_on_failure ? ERROR : LOG,
                    (errcode_for_file_access(),
                     errmsg("could not unlink temporary file \"%s\": %m",
                            path)));
        return false;
    }
 
    if (stat_errno == 0)
        ReportTemporaryFileUsage(path, filestats.st_size);
    else
    {
        errno = stat_errno;
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not stat file \"%s\": %m", path)));
    }
 
    return true;
}

References ereport, errcode_for_file_access(), errmsg(), ERROR, fb(), LOG, ReportTemporaryFileUsage(), and stat.

Referenced by FileSetDelete(), and unlink_if_exists_fname().

PathNameOpenFile()

File PathNameOpenFile	(	const char *	fileName,
		int	fileFlags
	)

Definition at line 1562 of file fd.c.

{
    return PathNameOpenFilePerm(fileName, fileFlags, pg_file_create_mode);
}

References PathNameOpenFilePerm(), and pg_file_create_mode.

Referenced by _mdfd_openseg(), bbsink_server_begin_archive(), bbsink_server_begin_manifest(), logical_rewrite_log_mapping(), mdcreate(), mdopenfork(), mdsyncfiletag(), OpenTemporaryFileInTablespace(), OpenWalSummaryFile(), PathNameCreateTemporaryFile(), PathNameOpenTemporaryFile(), ReorderBufferRestoreChanges(), and SummarizeWAL().

PathNameOpenFilePerm()

File PathNameOpenFilePerm	(	const char *	fileName,
		int	fileFlags,
		mode_t	fileMode
	)

Definition at line 1575 of file fd.c.

{
    char       *fnamecopy;
    File        file;
    Vfd        *vfdP;
 
    DO_DB(elog(LOG, "PathNameOpenFilePerm: %s %x %o",
               fileName, fileFlags, fileMode));
 
    /*
     * We need a malloc'd copy of the file name; fail cleanly if no room.
     */
    fnamecopy = strdup(fileName);
    if (fnamecopy == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_OUT_OF_MEMORY),
                 errmsg("out of memory")));
 
    file = AllocateVfd();
    vfdP = &VfdCache[file];
 
    /* Close excess kernel FDs. */
    ReleaseLruFiles();
 
    /*
     * Descriptors managed by VFDs are implicitly marked O_CLOEXEC.  The
     * client shouldn't be expected to know which kernel descriptors are
     * currently open, so it wouldn't make sense for them to be inherited by
     * executed subprograms.
     */
    fileFlags |= O_CLOEXEC;
 
    vfdP->fd = BasicOpenFilePerm(fileName, fileFlags, fileMode);
 
    if (vfdP->fd < 0)
    {
        int         save_errno = errno;
 
        FreeVfd(file);
        free(fnamecopy);
        errno = save_errno;
        return -1;
    }
    ++nfile;
    DO_DB(elog(LOG, "PathNameOpenFile: success %d",
               vfdP->fd));
 
    vfdP->fileName = fnamecopy;
    /* Saved flags are adjusted to be OK for re-opening file */
    vfdP->fileFlags = fileFlags & ~(O_CREAT | O_TRUNC | O_EXCL);
    vfdP->fileMode = fileMode;
    vfdP->fileSize = 0;
    vfdP->fdstate = 0x0;
    vfdP->resowner = NULL;
 
    Insert(file);
 
    return file;
}

References AllocateVfd(), BasicOpenFilePerm(), DO_DB, elog, ereport, errcode(), errmsg(), ERROR, fb(), free, FreeVfd(), Insert(), LOG, nfile, O_CLOEXEC, ReleaseLruFiles(), and VfdCache.

Referenced by PathNameOpenFile().

PathNameOpenTemporaryFile()

File PathNameOpenTemporaryFile	(	const char *	path,
		int	mode
	)

Definition at line 1888 of file fd.c.

{
    File        file;
 
    Assert(temporary_files_allowed);    /* check temp file access is up */
 
    ResourceOwnerEnlarge(CurrentResourceOwner);
 
    file = PathNameOpenFile(path, mode | PG_BINARY);
 
    /* If no such file, then we don't raise an error. */
    if (file <= 0 && errno != ENOENT)
        ereport(ERROR,
                (errcode_for_file_access(),
                 errmsg("could not open temporary file \"%s\": %m",
                        path)));
 
    if (file > 0)
    {
        /* Register it for automatic close. */
        RegisterTemporaryFile(file);
    }
 
    return file;
}

References Assert, CurrentResourceOwner, ereport, errcode_for_file_access(), errmsg(), ERROR, fb(), mode, PathNameOpenFile(), PG_BINARY, RegisterTemporaryFile(), and ResourceOwnerEnlarge().

Referenced by FileSetOpen().

pg_fdatasync()

int pg_fdatasync

(

int

fd

)

Definition at line 480 of file fd.c.

{
    int         rc;
 
    if (!enableFsync)
        return 0;
 
retry:
    rc = fdatasync(fd);
 
    if (rc == -1 && errno == EINTR)
        goto retry;
 
    return rc;
}

References EINTR, enableFsync, fb(), fd(), and fdatasync().

Referenced by issue_xlog_fsync().

pg_file_exists()

bool pg_file_exists

(

const char *

name

)

Definition at line 503 of file fd.c.

{
    struct stat st;
 
    Assert(name != NULL);
 
    if (stat(name, &st) == 0)
        return !S_ISDIR(st.st_mode);
    else if (!(errno == ENOENT || errno == ENOTDIR || errno == EACCES))
        ereport(ERROR,
                (errcode_for_file_access(),
                 errmsg("could not access file \"%s\": %m", name)));
 
    return false;
}

References Assert, ereport, errcode_for_file_access(), errmsg(), ERROR, fb(), name, S_ISDIR, stat::st_mode, and stat.

Referenced by expand_dynamic_library_name(), find_in_path(), find_in_paths(), and provider_init().

pg_flush_data()

void pg_flush_data	(	int	fd,
		pgoff_t	offset,
		pgoff_t	nbytes
	)

Definition at line 525 of file fd.c.

{
    /*
     * Right now file flushing is primarily used to avoid making later
     * fsync()/fdatasync() calls have less impact. Thus don't trigger flushes
     * if fsyncs are disabled - that's a decision we might want to make
     * configurable at some point.
     */
    if (!enableFsync)
        return;
 
    /*
     * We compile all alternatives that are supported on the current platform,
     * to find portability problems more easily.
     */
#if defined(HAVE_SYNC_FILE_RANGE)
    {
        int         rc;
        static bool not_implemented_by_kernel = false;
 
        if (not_implemented_by_kernel)
            return;
 
retry:
 
        /*
         * sync_file_range(SYNC_FILE_RANGE_WRITE), currently linux specific,
         * tells the OS that writeback for the specified blocks should be
         * started, but that we don't want to wait for completion.  Note that
         * this call might block if too much dirty data exists in the range.
         * This is the preferable method on OSs supporting it, as it works
         * reliably when available (contrast to msync()) and doesn't flush out
         * clean data (like FADV_DONTNEED).
         */
        rc = sync_file_range(fd, offset, nbytes,
                             SYNC_FILE_RANGE_WRITE);
        if (rc != 0)
        {
            int         elevel;
 
            if (rc == EINTR)
                goto retry;
 
            /*
             * For systems that don't have an implementation of
             * sync_file_range() such as Windows WSL, generate only one
             * warning and then suppress all further attempts by this process.
             */
            if (errno == ENOSYS)
            {
                elevel = WARNING;
                not_implemented_by_kernel = true;
            }
            else
                elevel = data_sync_elevel(WARNING);
 
            ereport(elevel,
                    (errcode_for_file_access(),
                     errmsg("could not flush dirty data: %m")));
        }
 
        return;
    }
#endif
#if !defined(WIN32) && defined(MS_ASYNC)
    {
        void       *p;
        static int  pagesize = 0;
 
        /*
         * On several OSs msync(MS_ASYNC) on a mmap'ed file triggers
         * writeback. On linux it only does so if MS_SYNC is specified, but
         * then it does the writeback synchronously. Luckily all common linux
         * systems have sync_file_range().  This is preferable over
         * FADV_DONTNEED because it doesn't flush out clean data.
         *
         * We map the file (mmap()), tell the kernel to sync back the contents
         * (msync()), and then remove the mapping again (munmap()).
         */
 
        /* mmap() needs actual length if we want to map whole file */
        if (offset == 0 && nbytes == 0)
        {
            nbytes = lseek(fd, 0, SEEK_END);
            if (nbytes < 0)
            {
                ereport(WARNING,
                        (errcode_for_file_access(),
                         errmsg("could not determine dirty data size: %m")));
                return;
            }
        }
 
        /*
         * Some platforms reject partial-page mmap() attempts.  To deal with
         * that, just truncate the request to a page boundary.  If any extra
         * bytes don't get flushed, well, it's only a hint anyway.
         */
 
        /* fetch pagesize only once */
        if (pagesize == 0)
            pagesize = sysconf(_SC_PAGESIZE);
 
        /* align length to pagesize, dropping any fractional page */
        if (pagesize > 0)
            nbytes = (nbytes / pagesize) * pagesize;
 
        /* fractional-page request is a no-op */
        if (nbytes <= 0)
            return;
 
        /*
         * mmap could well fail, particularly on 32-bit platforms where there
         * may simply not be enough address space.  If so, silently fall
         * through to the next implementation.
         */
        if (nbytes <= (pgoff_t) SSIZE_MAX)
            p = mmap(NULL, nbytes, PROT_READ, MAP_SHARED, fd, offset);
        else
            p = MAP_FAILED;
 
        if (p != MAP_FAILED)
        {
            int         rc;
 
            rc = msync(p, (size_t) nbytes, MS_ASYNC);
            if (rc != 0)
            {
                ereport(data_sync_elevel(WARNING),
                        (errcode_for_file_access(),
                         errmsg("could not flush dirty data: %m")));
                /* NB: need to fall through to munmap()! */
            }
 
            rc = munmap(p, (size_t) nbytes);
            if (rc != 0)
            {
                /* FATAL error because mapping would remain */
                ereport(FATAL,
                        (errcode_for_file_access(),
                         errmsg("could not munmap() while flushing data: %m")));
            }
 
            return;
        }
    }
#endif
#if defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_DONTNEED)
    {
        int         rc;
 
        /*
         * Signal the kernel that the passed in range should not be cached
         * anymore. This has the, desired, side effect of writing out dirty
         * data, and the, undesired, side effect of likely discarding useful
         * clean cached blocks.  For the latter reason this is the least
         * preferable method.
         */
 
        rc = posix_fadvise(fd, offset, nbytes, POSIX_FADV_DONTNEED);
 
        if (rc != 0)
        {
            /* don't error out, this is just a performance optimization */
            ereport(WARNING,
                    (errcode_for_file_access(),
                     errmsg("could not flush dirty data: %m")));
        }
 
        return;
    }
#endif
}

References data_sync_elevel(), EINTR, enableFsync, ereport, errcode_for_file_access(), errmsg(), FATAL, fb(), fd(), MAP_FAILED, and WARNING.

Referenced by copy_file(), and FileWriteback().

pg_fsync()

int pg_fsync

(

int

fd

)

Definition at line 389 of file fd.c.

{
#if !defined(WIN32) && defined(USE_ASSERT_CHECKING)
    struct stat st;
 
    /*
     * Some operating system implementations of fsync() have requirements
     * about the file access modes that were used when their file descriptor
     * argument was opened, and these requirements differ depending on whether
     * the file descriptor is for a directory.
     *
     * For any file descriptor that may eventually be handed to fsync(), we
     * should have opened it with access modes that are compatible with
     * fsync() on all supported systems, otherwise the code may not be
     * portable, even if it runs ok on the current system.
     *
     * We assert here that a descriptor for a file was opened with write
     * permissions (i.e., not O_RDONLY) and for a directory without write
     * permissions (O_RDONLY).  Notice that the assertion check is made even
     * if fsync() is disabled.
     *
     * If fstat() fails, ignore it and let the follow-up fsync() complain.
     */
    if (fstat(fd, &st) == 0)
    {
        int         desc_flags = fcntl(fd, F_GETFL);
 
        desc_flags &= O_ACCMODE;
 
        if (S_ISDIR(st.st_mode))
            Assert(desc_flags == O_RDONLY);
        else
            Assert(desc_flags != O_RDONLY);
    }
    errno = 0;
#endif
 
    /* #if is to skip the wal_sync_method test if there's no need for it */
#if defined(HAVE_FSYNC_WRITETHROUGH)
    if (wal_sync_method == WAL_SYNC_METHOD_FSYNC_WRITETHROUGH)
        return pg_fsync_writethrough(fd);
    else
#endif
        return pg_fsync_no_writethrough(fd);
}

References Assert, fb(), fd(), fstat, pg_fsync_no_writethrough(), pg_fsync_writethrough(), S_ISDIR, stat::st_mode, wal_sync_method, and WAL_SYNC_METHOD_FSYNC_WRITETHROUGH.

Referenced by AddToDataDirLockFile(), assign_wal_sync_method(), BootStrapXLOG(), CheckPointLogicalRewriteHeap(), CreateDirAndVersionFile(), CreateLockFile(), durable_rename(), FileSync(), fsync_fname_ext(), heap_xlog_logical_rewrite(), readRecoverySignalFile(), RecreateTwoPhaseFile(), RestoreSlotFromDisk(), SaveSlotToPath(), SlruPhysicalWritePage(), SlruSyncFileTag(), SnapBuildSerialize(), update_controlfile(), write_auto_conf_file(), WriteControlFile(), writeTimeLineHistory(), writeTimeLineHistoryFile(), XLogFileCopy(), and XLogFileInitInternal().

pg_fsync_no_writethrough()

int pg_fsync_no_writethrough

(

int

fd

)

Definition at line 441 of file fd.c.

{
    int         rc;
 
    if (!enableFsync)
        return 0;
 
retry:
    rc = fsync(fd);
 
    if (rc == -1 && errno == EINTR)
        goto retry;
 
    return rc;
}

References EINTR, enableFsync, fb(), fd(), and fsync.

Referenced by issue_xlog_fsync(), and pg_fsync().

pg_fsync_writethrough()

int pg_fsync_writethrough

(

int

fd

)

Definition at line 461 of file fd.c.

{
    if (enableFsync)
    {
#if defined(F_FULLFSYNC)
        return (fcntl(fd, F_FULLFSYNC, 0) == -1) ? -1 : 0;
#else
        errno = ENOSYS;
        return -1;
#endif
    }
    else
        return 0;
}

References enableFsync, fb(), and fd().

Referenced by issue_xlog_fsync(), pg_fsync(), and test_sync().

pg_ftruncate()

static int pg_ftruncate ( int  fd, pgoff_t  length  )

static

Definition at line 703 of file fd.c.

{
    int         ret;
 
retry:
    ret = ftruncate(fd, length);
 
    if (ret == -1 && errno == EINTR)
        goto retry;
 
    return ret;
}

References EINTR, fb(), and fd().

Referenced by FileTruncate(), and pg_truncate().

pg_truncate()

int pg_truncate	(	const char *	path,
		pgoff_t	length
	)

Definition at line 720 of file fd.c.

{
    int         ret;
#ifdef WIN32
    int         save_errno;
    int         fd;
 
    fd = OpenTransientFile(path, O_RDWR | PG_BINARY);
    if (fd >= 0)
    {
        ret = pg_ftruncate(fd, length);
        save_errno = errno;
        CloseTransientFile(fd);
        errno = save_errno;
    }
    else
        ret = -1;
#else
 
retry:
    ret = truncate(path, length);
 
    if (ret == -1 && errno == EINTR)
        goto retry;
#endif
 
    return ret;
}

References CloseTransientFile(), EINTR, fb(), fd(), OpenTransientFile(), PG_BINARY, and pg_ftruncate().

Referenced by do_truncate().

ReadDir()

struct dirent * ReadDir	(	DIR *	dir,
		const char *	dirname
	)

Definition at line 2956 of file fd.c.

{
    return ReadDirExtended(dir, dirname, ERROR);
}

References ERROR, and ReadDirExtended().

Referenced by calculate_database_size(), calculate_tablespace_size(), CheckPointLogicalRewriteHeap(), CheckPointSnapBuild(), CheckTablespaceDirectory(), CleanupBackupHistory(), copydir(), db_dir_size(), destroy_tablespace_directories(), directory_is_empty(), do_pg_backup_start(), dsm_cleanup_for_mmap(), extension_file_exists(), get_ext_ver_list(), GetConfFilesInDir(), GetWalSummaries(), movedb(), perform_base_backup(), pg_available_extension_versions(), pg_available_extensions(), pg_ls_dir(), pg_ls_dir_files(), pg_tablespace_databases(), pg_tzenumerate_next(), pgarch_readyXlog(), RemoveNonParentXlogFiles(), RemoveOldXlogFiles(), RemoveTempXlogFiles(), ResetUnloggedRelations(), ResetUnloggedRelationsInDbspaceDir(), ResetUnloggedRelationsInTablespaceDir(), restoreTwoPhaseData(), sendDir(), SlruScanDirectory(), StartupReorderBuffer(), StartupReplicationSlots(), UpdateLogicalMappings(), and XLogGetOldestSegno().

ReadDirExtended()

struct dirent * ReadDirExtended	(	DIR *	dir,
		const char *	dirname,
		int	elevel
	)

Definition at line 2971 of file fd.c.

{
    struct dirent *dent;
 
    /* Give a generic message for AllocateDir failure, if caller didn't */
    if (dir == NULL)
    {
        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not open directory \"%s\": %m",
                        dirname)));
        return NULL;
    }
 
    errno = 0;
    if ((dent = readdir(dir)) != NULL)
        return dent;
 
    if (errno)
        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not read directory \"%s\": %m",
                        dirname)));
    return NULL;
}

References ereport, errcode_for_file_access(), errmsg(), fb(), and readdir().

Referenced by DeleteAllExportedSnapshotFiles(), ReadDir(), RelationCacheInitFileRemove(), RelationCacheInitFileRemoveInDir(), RemovePgTempFiles(), RemovePgTempFilesInDir(), RemovePgTempRelationFiles(), RemovePgTempRelationFilesInDbspace(), ReorderBufferCleanupSerializedTXNs(), scan_directory_ci(), SyncDataDirectory(), and walkdir().

RegisterTemporaryFile()

static void RegisterTemporaryFile ( File  file )

static

Definition at line 1534 of file fd.c.

{
    ResourceOwnerRememberFile(CurrentResourceOwner, file);
    VfdCache[file].resowner = CurrentResourceOwner;
 
    /* Backup mechanism for closing at end of xact. */
    VfdCache[file].fdstate |= FD_CLOSE_AT_EOXACT;
    have_xact_temporary_files = true;
}

References CurrentResourceOwner, FD_CLOSE_AT_EOXACT, vfd::fdstate, have_xact_temporary_files, ResourceOwnerRememberFile(), vfd::resowner, and VfdCache.

Referenced by OpenTemporaryFile(), PathNameCreateTemporaryFile(), and PathNameOpenTemporaryFile().

ReleaseExternalFD()

void ReleaseExternalFD

(

void

)

Definition at line 1224 of file fd.c.

{
    Assert(numExternalFDs > 0);
    numExternalFDs--;
}

References Assert, and numExternalFDs.

Referenced by ClosePostmasterPorts(), CreateWaitEventSet(), dsm_impl_posix(), FreeWaitEventSet(), FreeWaitEventSetAfterFork(), InitializeWaitEventSupport(), libpqsrv_connect_internal(), libpqsrv_disconnect(), and XLogFileClose().

ReleaseLruFile()

static bool ReleaseLruFile ( void  )

static

Definition at line 1369 of file fd.c.

{
    DO_DB(elog(LOG, "ReleaseLruFile. Opened %d", nfile));
 
    if (nfile > 0)
    {
        /*
         * There are opened files and so there should be at least one used vfd
         * in the ring.
         */
        Assert(VfdCache[0].lruMoreRecently != 0);
        LruDelete(VfdCache[0].lruMoreRecently);
        return true;            /* freed a file */
    }
    return false;               /* no files available to free */
}

References Assert, DO_DB, elog, LOG, LruDelete(), nfile, and VfdCache.

Referenced by AllocateDir(), AllocateFile(), BasicOpenFilePerm(), OpenPipeStream(), and ReleaseLruFiles().

ReleaseLruFiles()

static void ReleaseLruFiles ( void  )

static

Definition at line 1391 of file fd.c.

{
    while (nfile + numAllocatedDescs + numExternalFDs >= max_safe_fds)
    {
        if (!ReleaseLruFile())
            break;
    }
}

References max_safe_fds, nfile, numAllocatedDescs, numExternalFDs, and ReleaseLruFile().

Referenced by AllocateDir(), AllocateFile(), LruInsert(), OpenPipeStream(), OpenTransientFilePerm(), PathNameOpenFilePerm(), and ReserveExternalFD().

RemovePgTempFiles()

void RemovePgTempFiles

(

void

)

Definition at line 3322 of file fd.c.

{
    char        temp_path[MAXPGPATH + sizeof(PG_TBLSPC_DIR) + sizeof(TABLESPACE_VERSION_DIRECTORY) + sizeof(PG_TEMP_FILES_DIR)];
    DIR        *spc_dir;
    struct dirent *spc_de;
 
    /*
     * First process temp files in pg_default ($PGDATA/base)
     */
    snprintf(temp_path, sizeof(temp_path), "base/%s", PG_TEMP_FILES_DIR);
    RemovePgTempFilesInDir(temp_path, true, false);
    RemovePgTempRelationFiles("base");
 
    /*
     * Cycle through temp directories for all non-default tablespaces.
     */
    spc_dir = AllocateDir(PG_TBLSPC_DIR);
 
    while ((spc_de = ReadDirExtended(spc_dir, PG_TBLSPC_DIR, LOG)) != NULL)
    {
        if (strcmp(spc_de->d_name, ".") == 0 ||
            strcmp(spc_de->d_name, "..") == 0)
            continue;
 
        snprintf(temp_path, sizeof(temp_path), "%s/%s/%s/%s",
                 PG_TBLSPC_DIR, spc_de->d_name, TABLESPACE_VERSION_DIRECTORY,
                 PG_TEMP_FILES_DIR);
        RemovePgTempFilesInDir(temp_path, true, false);
 
        snprintf(temp_path, sizeof(temp_path), "%s/%s/%s",
                 PG_TBLSPC_DIR, spc_de->d_name, TABLESPACE_VERSION_DIRECTORY);
        RemovePgTempRelationFiles(temp_path);
    }
 
    FreeDir(spc_dir);
 
    /*
     * In EXEC_BACKEND case there is a pgsql_tmp directory at the top level of
     * DataDir as well.  However, that is *not* cleaned here because doing so
     * would create a race condition.  It's done separately, earlier in
     * postmaster startup.
     */
}

References AllocateDir(), fb(), FreeDir(), LOG, MAXPGPATH, PG_TBLSPC_DIR, PG_TEMP_FILES_DIR, ReadDirExtended(), RemovePgTempFilesInDir(), RemovePgTempRelationFiles(), snprintf, and TABLESPACE_VERSION_DIRECTORY.

Referenced by PostmasterMain(), and PostmasterStateMachine().

RemovePgTempFilesInDir()

void RemovePgTempFilesInDir	(	const char *	tmpdirname,
		bool	missing_ok,
		bool	unlink_all
	)

Definition at line 3382 of file fd.c.

{
    DIR        *temp_dir;
    struct dirent *temp_de;
    char        rm_path[MAXPGPATH * 2];
 
    temp_dir = AllocateDir(tmpdirname);
 
    if (temp_dir == NULL && errno == ENOENT && missing_ok)
        return;
 
    while ((temp_de = ReadDirExtended(temp_dir, tmpdirname, LOG)) != NULL)
    {
        if (strcmp(temp_de->d_name, ".") == 0 ||
            strcmp(temp_de->d_name, "..") == 0)
            continue;
 
        snprintf(rm_path, sizeof(rm_path), "%s/%s",
                 tmpdirname, temp_de->d_name);
 
        if (unlink_all ||
            strncmp(temp_de->d_name,
                    PG_TEMP_FILE_PREFIX,
                    strlen(PG_TEMP_FILE_PREFIX)) == 0)
        {
            PGFileType  type = get_dirent_type(rm_path, temp_de, false, LOG);
 
            if (type == PGFILETYPE_ERROR)
                continue;
            else if (type == PGFILETYPE_DIR)
            {
                /* recursively remove contents, then directory itself */
                RemovePgTempFilesInDir(rm_path, false, true);
 
                if (rmdir(rm_path) < 0)
                    ereport(LOG,
                            (errcode_for_file_access(),
                             errmsg("could not remove directory \"%s\": %m",
                                    rm_path)));
            }
            else
            {
                if (unlink(rm_path) < 0)
                    ereport(LOG,
                            (errcode_for_file_access(),
                             errmsg("could not remove file \"%s\": %m",
                                    rm_path)));
            }
        }
        else
            ereport(LOG,
                    (errmsg("unexpected file found in temporary-files directory: \"%s\"",
                            rm_path)));
    }
 
    FreeDir(temp_dir);
}

References AllocateDir(), ereport, errcode_for_file_access(), errmsg(), fb(), FreeDir(), get_dirent_type(), LOG, MAXPGPATH, PG_TEMP_FILE_PREFIX, PGFILETYPE_DIR, PGFILETYPE_ERROR, ReadDirExtended(), RemovePgTempFilesInDir(), snprintf, and type.

Referenced by PostmasterMain(), RemovePgTempFiles(), and RemovePgTempFilesInDir().

RemovePgTempRelationFiles()

static void RemovePgTempRelationFiles ( const char *  tsdirname )

static

Definition at line 3442 of file fd.c.

{
    DIR        *ts_dir;
    struct dirent *de;
    char        dbspace_path[MAXPGPATH * 2];
 
    ts_dir = AllocateDir(tsdirname);
 
    while ((de = ReadDirExtended(ts_dir, tsdirname, LOG)) != NULL)
    {
        /*
         * We're only interested in the per-database directories, which have
         * numeric names.  Note that this code will also (properly) ignore "."
         * and "..".
         */
        if (strspn(de->d_name, "0123456789") != strlen(de->d_name))
            continue;
 
        snprintf(dbspace_path, sizeof(dbspace_path), "%s/%s",
                 tsdirname, de->d_name);
        RemovePgTempRelationFilesInDbspace(dbspace_path);
    }
 
    FreeDir(ts_dir);
}

References AllocateDir(), fb(), FreeDir(), LOG, MAXPGPATH, ReadDirExtended(), RemovePgTempRelationFilesInDbspace(), and snprintf.

Referenced by RemovePgTempFiles().

RemovePgTempRelationFilesInDbspace()

static void RemovePgTempRelationFilesInDbspace ( const char *  dbspacedirname )

static

Definition at line 3470 of file fd.c.

{
    DIR        *dbspace_dir;
    struct dirent *de;
    char        rm_path[MAXPGPATH * 2];
 
    dbspace_dir = AllocateDir(dbspacedirname);
 
    while ((de = ReadDirExtended(dbspace_dir, dbspacedirname, LOG)) != NULL)
    {
        if (!looks_like_temp_rel_name(de->d_name))
            continue;
 
        snprintf(rm_path, sizeof(rm_path), "%s/%s",
                 dbspacedirname, de->d_name);
 
        if (unlink(rm_path) < 0)
            ereport(LOG,
                    (errcode_for_file_access(),
                     errmsg("could not remove file \"%s\": %m",
                            rm_path)));
    }
 
    FreeDir(dbspace_dir);
}

References AllocateDir(), ereport, errcode_for_file_access(), errmsg(), fb(), FreeDir(), LOG, looks_like_temp_rel_name(), MAXPGPATH, ReadDirExtended(), and snprintf.

Referenced by RemovePgTempRelationFiles().

ReportTemporaryFileUsage()

static void ReportTemporaryFileUsage ( const char *  path, pgoff_t  size  )

static

Definition at line 1515 of file fd.c.

{
    pgstat_report_tempfile(size);
 
    if (log_temp_files >= 0)
    {
        if ((size / 1024) >= log_temp_files)
            ereport(LOG,
                    (errmsg("temporary file: path \"%s\", size %lu",
                            path, (unsigned long) size)));
    }
}

References ereport, errmsg(), LOG, log_temp_files, and pgstat_report_tempfile().

Referenced by FileClose(), and PathNameDeleteTemporaryFile().

reserveAllocatedDesc()

static bool reserveAllocatedDesc ( void  )

static

Definition at line 2552 of file fd.c.

{
    AllocateDesc *newDescs;
    int         newMax;
 
    /* Quick out if array already has a free slot. */
    if (numAllocatedDescs < maxAllocatedDescs)
        return true;
 
    /*
     * If the array hasn't yet been created in the current process, initialize
     * it with FD_MINFREE / 3 elements.  In many scenarios this is as many as
     * we will ever need, anyway.  We don't want to look at max_safe_fds
     * immediately because set_max_safe_fds() may not have run yet.
     */
    if (allocatedDescs == NULL)
    {
        newMax = FD_MINFREE / 3;
        newDescs = (AllocateDesc *) malloc(newMax * sizeof(AllocateDesc));
        /* Out of memory already?  Treat as fatal error. */
        if (newDescs == NULL)
            ereport(ERROR,
                    (errcode(ERRCODE_OUT_OF_MEMORY),
                     errmsg("out of memory")));
        allocatedDescs = newDescs;
        maxAllocatedDescs = newMax;
        return true;
    }
 
    /*
     * Consider enlarging the array beyond the initial allocation used above.
     * By the time this happens, max_safe_fds should be known accurately.
     *
     * We mustn't let allocated descriptors hog all the available FDs, and in
     * practice we'd better leave a reasonable number of FDs for VFD use.  So
     * set the maximum to max_safe_fds / 3.  (This should certainly be at
     * least as large as the initial size, FD_MINFREE / 3, so we aren't
     * tightening the restriction here.)  Recall that "external" FDs are
     * allowed to consume another third of max_safe_fds.
     */
    newMax = max_safe_fds / 3;
    if (newMax > maxAllocatedDescs)
    {
        newDescs = (AllocateDesc *) realloc(allocatedDescs,
                                            newMax * sizeof(AllocateDesc));
        /* Treat out-of-memory as a non-fatal error. */
        if (newDescs == NULL)
            return false;
        allocatedDescs = newDescs;
        maxAllocatedDescs = newMax;
        return true;
    }
 
    /* Can't enlarge allocatedDescs[] any more. */
    return false;
}

References allocatedDescs, ereport, errcode(), errmsg(), ERROR, fb(), FD_MINFREE, malloc, max_safe_fds, maxAllocatedDescs, numAllocatedDescs, and realloc.

Referenced by AllocateDir(), AllocateFile(), OpenPipeStream(), and OpenTransientFilePerm().

ReserveExternalFD()

void ReserveExternalFD

(

void

)

Definition at line 1206 of file fd.c.

{
    /*
     * Release VFDs if needed to stay safe.  Because we do this before
     * incrementing numExternalFDs, the final state will be as desired, i.e.,
     * nfile + numAllocatedDescs + numExternalFDs <= max_safe_fds.
     */
    ReleaseLruFiles();
 
    numExternalFDs++;
}

References numExternalFDs, and ReleaseLruFiles().

Referenced by AcquireExternalFD(), BackendInitialize(), dsm_impl_posix(), InitializeWaitEventSupport(), InitPostmasterDeathWatchHandle(), and XLogWrite().

ResourceOwnerForgetFile()

static void ResourceOwnerForgetFile ( ResourceOwner  owner, File  file  )

inlinestatic

Definition at line 380 of file fd.c.

{
    ResourceOwnerForget(owner, Int32GetDatum(file), &file_resowner_desc);
}

References file_resowner_desc, Int32GetDatum(), and ResourceOwnerForget().

Referenced by FileClose().

ResourceOwnerRememberFile()

static void ResourceOwnerRememberFile ( ResourceOwner  owner, File  file  )

inlinestatic

Definition at line 375 of file fd.c.

{
    ResourceOwnerRemember(owner, Int32GetDatum(file), &file_resowner_desc);
}

References file_resowner_desc, Int32GetDatum(), and ResourceOwnerRemember().

Referenced by RegisterTemporaryFile().

ResOwnerPrintFile()

static char * ResOwnerPrintFile ( Datum  res )

static

Definition at line 4102 of file fd.c.

{
    return psprintf("File %d", DatumGetInt32(res));
}

References DatumGetInt32(), and psprintf().

ResOwnerReleaseFile()

static void ResOwnerReleaseFile ( Datum  res )

static

Definition at line 4088 of file fd.c.

{
    File        file = (File) DatumGetInt32(res);
    Vfd        *vfdP;
 
    Assert(FileIsValid(file));
 
    vfdP = &VfdCache[file];
    vfdP->resowner = NULL;
 
    FileClose(file);
}

References Assert, DatumGetInt32(), fb(), FileClose(), FileIsValid, vfd::resowner, and VfdCache.

set_max_safe_fds()

void set_max_safe_fds

(

void

)

Definition at line 1044 of file fd.c.

{
    int         usable_fds;
    int         already_open;
 
    /*----------
     * We want to set max_safe_fds to
     *          MIN(usable_fds, max_files_per_process)
     * less the slop factor for files that are opened without consulting
     * fd.c.  This ensures that we won't allow to open more than
     * max_files_per_process, or the experimentally-determined EMFILE limit,
     * additional files.
     *----------
     */
    count_usable_fds(max_files_per_process,
                     &usable_fds, &already_open);
 
    max_safe_fds = Min(usable_fds, max_files_per_process);
 
    /*
     * Take off the FDs reserved for system() etc.
     */
    max_safe_fds -= NUM_RESERVED_FDS;
 
    /*
     * Make sure we still have enough to get by.
     */
    if (max_safe_fds < FD_MINFREE)
        ereport(FATAL,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("insufficient file descriptors available to start server process"),
                 errdetail("System allows %d, server needs at least %d, %d files are already open.",
                           max_safe_fds + NUM_RESERVED_FDS,
                           FD_MINFREE + NUM_RESERVED_FDS,
                           already_open)));
 
    elog(DEBUG2, "max_safe_fds = %d, usable_fds = %d, already_open = %d",
         max_safe_fds, usable_fds, already_open);
}

References count_usable_fds(), DEBUG2, elog, ereport, errcode(), errdetail(), errmsg(), FATAL, fb(), FD_MINFREE, max_files_per_process, max_safe_fds, Min, and NUM_RESERVED_FDS.

Referenced by BootstrapModeMain(), PostgresSingleUserMain(), and PostmasterMain().

SetTempTablespaces()

void SetTempTablespaces	(	Oid *	tableSpaces,
		int	numSpaces
	)

Definition at line 3096 of file fd.c.

{
    Assert(numSpaces >= 0);
    tempTableSpaces = tableSpaces;
    numTempTableSpaces = numSpaces;
 
    /*
     * Select a random starting point in the list.  This is to minimize
     * conflicts between backends that are most likely sharing the same list
     * of temp tablespaces.  Note that if we create multiple temp files in the
     * same transaction, we'll advance circularly through the list --- this
     * ensures that large temporary sort files are nicely spread across all
     * available tablespaces.
     */
    if (numSpaces > 1)
        nextTempTableSpace = pg_prng_uint64_range(&pg_global_prng_state,
                                                  0, numSpaces - 1);
    else
        nextTempTableSpace = 0;
}

References Assert, fb(), nextTempTableSpace, numTempTableSpaces, pg_global_prng_state, pg_prng_uint64_range(), and tempTableSpaces.

Referenced by assign_temp_tablespaces(), and PrepareTempTablespaces().

SyncDataDirectory()

void SyncDataDirectory

(

void

)

Definition at line 3593 of file fd.c.

{
    bool        xlog_is_symlink;
 
    /* We can skip this whole thing if fsync is disabled. */
    if (!enableFsync)
        return;
 
    /*
     * If pg_wal is a symlink, we'll need to recurse into it separately,
     * because the first walkdir below will ignore it.
     */
    xlog_is_symlink = false;
 
    {
        struct stat st;
 
        if (lstat("pg_wal", &st) < 0)
            ereport(LOG,
                    (errcode_for_file_access(),
                     errmsg("could not stat file \"%s\": %m",
                            "pg_wal")));
        else if (S_ISLNK(st.st_mode))
            xlog_is_symlink = true;
    }
 
#ifdef HAVE_SYNCFS
    if (recovery_init_sync_method == DATA_DIR_SYNC_METHOD_SYNCFS)
    {
        DIR        *dir;
        struct dirent *de;
 
        /*
         * On Linux, we don't have to open every single file one by one.  We
         * can use syncfs() to sync whole filesystems.  We only expect
         * filesystem boundaries to exist where we tolerate symlinks, namely
         * pg_wal and the tablespaces, so we call syncfs() for each of those
         * directories.
         */
 
        /* Prepare to report progress syncing the data directory via syncfs. */
        begin_startup_progress_phase();
 
        /* Sync the top level pgdata directory. */
        do_syncfs(".");
        /* If any tablespaces are configured, sync each of those. */
        dir = AllocateDir(PG_TBLSPC_DIR);
        while ((de = ReadDirExtended(dir, PG_TBLSPC_DIR, LOG)))
        {
            char        path[MAXPGPATH];
 
            if (strcmp(de->d_name, ".") == 0 || strcmp(de->d_name, "..") == 0)
                continue;
 
            snprintf(path, MAXPGPATH, "%s/%s", PG_TBLSPC_DIR, de->d_name);
            do_syncfs(path);
        }
        FreeDir(dir);
        /* If pg_wal is a symlink, process that too. */
        if (xlog_is_symlink)
            do_syncfs("pg_wal");
        return;
    }
#endif                          /* !HAVE_SYNCFS */
 
#ifdef PG_FLUSH_DATA_WORKS
    /* Prepare to report progress of the pre-fsync phase. */
    begin_startup_progress_phase();
 
    /*
     * If possible, hint to the kernel that we're soon going to fsync the data
     * directory and its contents.  Errors in this step are even less
     * interesting than normal, so log them only at DEBUG1.
     */
    walkdir(".", pre_sync_fname, false, DEBUG1);
    if (xlog_is_symlink)
        walkdir("pg_wal", pre_sync_fname, false, DEBUG1);
    walkdir(PG_TBLSPC_DIR, pre_sync_fname, true, DEBUG1);
#endif
 
    /* Prepare to report progress syncing the data directory via fsync. */
    begin_startup_progress_phase();
 
    /*
     * Now we do the fsync()s in the same order.
     *
     * The main call ignores symlinks, so in addition to specially processing
     * pg_wal if it's a symlink, pg_tblspc has to be visited separately with
     * process_symlinks = true.  Note that if there are any plain directories
     * in pg_tblspc, they'll get fsync'd twice.  That's not an expected case
     * so we don't worry about optimizing it.
     */
    walkdir(".", datadir_fsync_fname, false, LOG);
    if (xlog_is_symlink)
        walkdir("pg_wal", datadir_fsync_fname, false, LOG);
    walkdir(PG_TBLSPC_DIR, datadir_fsync_fname, true, LOG);
}

References AllocateDir(), begin_startup_progress_phase(), DATA_DIR_SYNC_METHOD_SYNCFS, datadir_fsync_fname(), DEBUG1, enableFsync, ereport, errcode_for_file_access(), errmsg(), fb(), FreeDir(), LOG, lstat, MAXPGPATH, PG_TBLSPC_DIR, ReadDirExtended(), recovery_init_sync_method, S_ISLNK, snprintf, stat::st_mode, and walkdir().

Referenced by StartupXLOG().

TempTablespacePath()

void TempTablespacePath	(	char *	path,
		Oid	tablespace
	)

Definition at line 1766 of file fd.c.

{
    /*
     * Identify the tempfile directory for this tablespace.
     *
     * If someone tries to specify pg_global, use pg_default instead.
     */
    if (tablespace == InvalidOid ||
        tablespace == DEFAULTTABLESPACE_OID ||
        tablespace == GLOBALTABLESPACE_OID)
        snprintf(path, MAXPGPATH, "base/%s", PG_TEMP_FILES_DIR);
    else
    {
        /* All other tablespaces are accessed via symlinks */
        snprintf(path, MAXPGPATH, "%s/%u/%s/%s",
                 PG_TBLSPC_DIR, tablespace, TABLESPACE_VERSION_DIRECTORY,
                 PG_TEMP_FILES_DIR);
    }
}

References fb(), InvalidOid, MAXPGPATH, PG_TBLSPC_DIR, PG_TEMP_FILES_DIR, snprintf, tablespace, and TABLESPACE_VERSION_DIRECTORY.

Referenced by FileSetCreate(), FileSetPath(), OpenTemporaryFileInTablespace(), and pg_ls_tmpdir().

TempTablespacesAreSet()

bool TempTablespacesAreSet

(

void

)

Definition at line 3125 of file fd.c.

{
    return (numTempTableSpaces >= 0);
}

References numTempTableSpaces.

Referenced by GetTempTablespaces(), and PrepareTempTablespaces().

unlink_if_exists_fname()

static void unlink_if_exists_fname ( const char *  fname, bool  isdir, int  elevel  )

static

Definition at line 3821 of file fd.c.

{
    if (isdir)
    {
        if (rmdir(fname) != 0 && errno != ENOENT)
            ereport(elevel,
                    (errcode_for_file_access(),
                     errmsg("could not remove directory \"%s\": %m", fname)));
    }
    else
    {
        /* Use PathNameDeleteTemporaryFile to report filesize */
        PathNameDeleteTemporaryFile(fname, false);
    }
}

References ereport, errcode_for_file_access(), errmsg(), fb(), and PathNameDeleteTemporaryFile().

Referenced by PathNameDeleteTemporaryDir().

walkdir()

static void walkdir ( const char *  path, void(*)(const char *fname, bool isdir, int elevel)  action, bool  process_symlinks, int  elevel  )

static

Definition at line 3707 of file fd.c.

{
    DIR        *dir;
    struct dirent *de;
 
    dir = AllocateDir(path);
 
    while ((de = ReadDirExtended(dir, path, elevel)) != NULL)
    {
        char        subpath[MAXPGPATH * 2];
 
        CHECK_FOR_INTERRUPTS();
 
        if (strcmp(de->d_name, ".") == 0 ||
            strcmp(de->d_name, "..") == 0)
            continue;
 
        snprintf(subpath, sizeof(subpath), "%s/%s", path, de->d_name);
 
        switch (get_dirent_type(subpath, de, process_symlinks, elevel))
        {
            case PGFILETYPE_REG:
                (*action) (subpath, false, elevel);
                break;
            case PGFILETYPE_DIR:
                walkdir(subpath, action, false, elevel);
                break;
            default:
 
                /*
                 * Errors are already reported directly by get_dirent_type(),
                 * and any remaining symlinks and unknown file types are
                 * ignored.
                 */
                break;
        }
    }
 
    FreeDir(dir);               /* we ignore any error here */
 
    /*
     * It's important to fsync the destination directory itself as individual
     * file fsyncs don't guarantee that the directory entry for the file is
     * synced.  However, skip this if AllocateDir failed; the action function
     * might not be robust against that.
     */
    if (dir)
        (*action) (path, true, elevel);
}

References AllocateDir(), CHECK_FOR_INTERRUPTS, fb(), FreeDir(), get_dirent_type(), MAXPGPATH, PGFILETYPE_DIR, PGFILETYPE_REG, ReadDirExtended(), snprintf, subpath(), and walkdir().

Referenced by PathNameDeleteTemporaryDir(), SyncDataDirectory(), and walkdir().

Variable Documentation

allocatedDescs

AllocateDesc* allocatedDescs = NULL

static

Definition at line 272 of file fd.c.

Referenced by AllocateDir(), AllocateFile(), AtEOSubXact_Files(), CleanupTempFiles(), ClosePipeStream(), CloseTransientFile(), FreeDesc(), FreeDir(), FreeFile(), OpenPipeStream(), OpenTransientFilePerm(), and reserveAllocatedDesc().

data_sync_retry

bool data_sync_retry = false

Definition at line 162 of file fd.c.

Referenced by data_sync_elevel().

file_extend_method

int file_extend_method = DEFAULT_FILE_EXTEND_METHOD

Definition at line 168 of file fd.c.

Referenced by mdzeroextend().

file_resowner_desc

const ResourceOwnerDesc file_resowner_desc

static

Initial value:

=
{
    .name = "File",
    .release_phase = RESOURCE_RELEASE_AFTER_LOCKS,
    .release_priority = RELEASE_PRIO_FILES,
    .ReleaseResource = ResOwnerReleaseFile,
    .DebugPrint = ResOwnerPrintFile
}

Definition at line 364 of file fd.c.

{
    .name = "File",
    .release_phase = RESOURCE_RELEASE_AFTER_LOCKS,
    .release_priority = RELEASE_PRIO_FILES,
    .ReleaseResource = ResOwnerReleaseFile,
    .DebugPrint = ResOwnerPrintFile
};

Referenced by ResourceOwnerForgetFile(), and ResourceOwnerRememberFile().

have_xact_temporary_files

bool have_xact_temporary_files = false

static

Definition at line 231 of file fd.c.

Referenced by CleanupTempFiles(), and RegisterTemporaryFile().

io_direct_flags

int io_direct_flags

Definition at line 171 of file fd.c.

Referenced by _mdfd_open_flags(), assign_debug_io_direct(), get_sync_bit(), mdprefetch(), mdstartreadv(), mdwriteback(), PrefetchLocalBuffer(), PrefetchSharedBuffer(), read_stream_begin_impl(), ScheduleBufferTagForWriteback(), XLogFileClose(), XLogFileInitInternal(), and XLogPrefetcherNextBlock().

max_files_per_process

int max_files_per_process = 1000

Definition at line 146 of file fd.c.

Referenced by set_max_safe_fds().

max_safe_fds

int max_safe_fds = FD_MINFREE

Definition at line 159 of file fd.c.

Referenced by AcquireExternalFD(), ReleaseLruFiles(), reserveAllocatedDesc(), and set_max_safe_fds().

maxAllocatedDescs

int maxAllocatedDescs = 0

static

Definition at line 271 of file fd.c.

Referenced by AllocateDir(), AllocateFile(), OpenPipeStream(), OpenTransientFilePerm(), and reserveAllocatedDesc().

nextTempTableSpace

int nextTempTableSpace = 0

static

Definition at line 293 of file fd.c.

Referenced by GetNextTempTableSpace(), and SetTempTablespaces().

nfile

int nfile = 0

static

Definition at line 225 of file fd.c.

Referenced by FileClose(), LruDelete(), LruInsert(), PathNameOpenFilePerm(), ReleaseLruFile(), and ReleaseLruFiles().

numAllocatedDescs

int numAllocatedDescs = 0

static

Definition at line 270 of file fd.c.

Referenced by AllocateDir(), AllocateFile(), AtEOSubXact_Files(), CleanupTempFiles(), ClosePipeStream(), CloseTransientFile(), FreeDesc(), FreeDir(), FreeFile(), OpenPipeStream(), OpenTransientFilePerm(), ReleaseLruFiles(), and reserveAllocatedDesc().

numExternalFDs

int numExternalFDs = 0

static

Definition at line 277 of file fd.c.

Referenced by AcquireExternalFD(), ReleaseExternalFD(), ReleaseLruFiles(), and ReserveExternalFD().

numTempTableSpaces

int numTempTableSpaces = -1

static

Definition at line 292 of file fd.c.

Referenced by AtEOXact_Files(), GetNextTempTableSpace(), GetTempTablespaces(), OpenTemporaryFile(), SetTempTablespaces(), and TempTablespacesAreSet().

recovery_init_sync_method

int recovery_init_sync_method = DATA_DIR_SYNC_METHOD_FSYNC

Definition at line 165 of file fd.c.

Referenced by SyncDataDirectory().

SizeVfdCache

Size SizeVfdCache = 0

static

Definition at line 220 of file fd.c.

Referenced by AllocateVfd(), CleanupTempFiles(), closeAllVfds(), InitFileAccess(), and InitTemporaryFileAccess().

tempFileCounter

long tempFileCounter = 0

static

Definition at line 283 of file fd.c.

Referenced by OpenTemporaryFileInTablespace().

temporary_files_size

uint64 temporary_files_size = 0

static

Definition at line 239 of file fd.c.

Referenced by FileClose(), FileTruncate(), and FileWriteV().

tempTableSpaces

Oid* tempTableSpaces = NULL

static

Definition at line 291 of file fd.c.

Referenced by AtEOXact_Files(), GetNextTempTableSpace(), GetTempTablespaces(), and SetTempTablespaces().

VfdCache

Vfd* VfdCache

static

Definition at line 219 of file fd.c.

Referenced by AllocateVfd(), CleanupTempFiles(), Delete(), FileAccess(), FileClose(), FileFallocate(), FileGetRawDesc(), FileGetRawFlags(), FileGetRawMode(), FilePathName(), FilePrefetch(), FileReadV(), FileSize(), FileStartReadV(), FileSync(), FileTruncate(), FileWriteback(), FileWriteV(), FileZero(), FreeVfd(), InitFileAccess(), Insert(), LruDelete(), LruInsert(), OpenTemporaryFile(), PathNameCreateTemporaryFile(), PathNameOpenFilePerm(), RegisterTemporaryFile(), ReleaseLruFile(), and ResOwnerReleaseFile().