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file_utils.h File Reference
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Functions

int fsync_fname (const char *fname, bool isdir)
 
void fsync_pgdata (const char *pg_data, int serverVersion)
 
void fsync_dir_recurse (const char *dir)
 
int durable_rename (const char *oldfile, const char *newfile)
 
int fsync_parent_path (const char *fname)
 

Function Documentation

◆ durable_rename()

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

Definition at line 338 of file file_utils.c.

References close, EXIT_FAILURE, fd(), fsync, fsync_fname(), fsync_parent_path(), PG_BINARY, pg_log_error, and pg_log_fatal.

339 {
340  int fd;
341 
342  /*
343  * First fsync the old and target path (if it exists), to ensure that they
344  * are properly persistent on disk. Syncing the target file is not
345  * strictly necessary, but it makes it easier to reason about crashes;
346  * because it's then guaranteed that either source or target file exists
347  * after a crash.
348  */
349  if (fsync_fname(oldfile, false) != 0)
350  return -1;
351 
352  fd = open(newfile, PG_BINARY | O_RDWR, 0);
353  if (fd < 0)
354  {
355  if (errno != ENOENT)
356  {
357  pg_log_error("could not open file \"%s\": %m", newfile);
358  return -1;
359  }
360  }
361  else
362  {
363  if (fsync(fd) != 0)
364  {
365  pg_log_fatal("could not fsync file \"%s\": %m", newfile);
366  close(fd);
367  exit(EXIT_FAILURE);
368  }
369  close(fd);
370  }
371 
372  /* Time to do the real deal... */
373  if (rename(oldfile, newfile) != 0)
374  {
375  pg_log_error("could not rename file \"%s\" to \"%s\": %m",
376  oldfile, newfile);
377  return -1;
378  }
379 
380  /*
381  * To guarantee renaming the file is persistent, fsync the file with its
382  * new name, and its containing directory.
383  */
384  if (fsync_fname(newfile, false) != 0)
385  return -1;
386 
387  if (fsync_parent_path(newfile) != 0)
388  return -1;
389 
390  return 0;
391 }
int fsync_fname(const char *fname, bool isdir)
Definition: file_utils.c:255
int fsync_parent_path(const char *fname)
Definition: file_utils.c:311
#define pg_log_error(...)
Definition: logging.h:79
static int fd(const char *x, int i)
Definition: preproc-init.c:105
#define PG_BINARY
Definition: c.h:1234
#define fsync(fd)
Definition: win32_port.h:62
#define EXIT_FAILURE
Definition: settings.h:154
#define close(a)
Definition: win32.h:12
#define pg_log_fatal(...)
Definition: logging.h:75

◆ fsync_dir_recurse()

void fsync_dir_recurse ( const char *  dir)

Definition at line 120 of file file_utils.c.

References fsync_fname(), and walkdir().

Referenced by _CloseArchive(), and BaseBackup().

121 {
122  /*
123  * If possible, hint to the kernel that we're soon going to fsync the data
124  * directory and its contents.
125  */
126 #ifdef PG_FLUSH_DATA_WORKS
127  walkdir(dir, pre_sync_fname, false);
128 #endif
129 
130  walkdir(dir, fsync_fname, false);
131 }
int fsync_fname(const char *fname, bool isdir)
Definition: file_utils.c:255
static void walkdir(const char *path, int(*action)(const char *fname, bool isdir), bool process_symlinks)
Definition: file_utils.c:148

◆ fsync_fname()

int fsync_fname ( const char *  fname,
bool  isdir 
)

Definition at line 630 of file fd.c.

631 {
632  fsync_fname_ext(fname, isdir, false, data_sync_elevel(ERROR));
633 }
#define ERROR
Definition: elog.h:43
int data_sync_elevel(int elevel)
Definition: fd.c:3597
int fsync_fname_ext(const char *fname, bool isdir, bool ignore_perm, int elevel)
Definition: fd.c:3458

◆ fsync_parent_path()

int fsync_parent_path ( const char *  fname)

Definition at line 311 of file file_utils.c.

References fsync_fname(), get_parent_directory(), MAXPGPATH, and strlcpy().

Referenced by durable_rename().

312 {
313  char parentpath[MAXPGPATH];
314 
315  strlcpy(parentpath, fname, MAXPGPATH);
316  get_parent_directory(parentpath);
317 
318  /*
319  * get_parent_directory() returns an empty string if the input argument is
320  * just a file name (see comments in path.c), so handle that as being the
321  * current directory.
322  */
323  if (strlen(parentpath) == 0)
324  strlcpy(parentpath, ".", MAXPGPATH);
325 
326  if (fsync_fname(parentpath, true) != 0)
327  return -1;
328 
329  return 0;
330 }
int fsync_fname(const char *fname, bool isdir)
Definition: file_utils.c:255
#define MAXPGPATH
void get_parent_directory(char *path)
Definition: path.c:854
size_t strlcpy(char *dst, const char *src, size_t siz)
Definition: strlcpy.c:45

◆ fsync_pgdata()

void fsync_pgdata ( const char *  pg_data,
int  serverVersion 
)

Definition at line 56 of file file_utils.c.

References fsync_fname(), lstat, MAXPGPATH, MINIMUM_VERSION_FOR_PG_WAL, pg_log_error, pgwin32_is_junction(), snprintf, stat, and walkdir().

Referenced by BaseBackup(), main(), and syncTargetDirectory().

58 {
59  bool xlog_is_symlink;
60  char pg_wal[MAXPGPATH];
61  char pg_tblspc[MAXPGPATH];
62 
63  /* handle renaming of pg_xlog to pg_wal in post-10 clusters */
64  snprintf(pg_wal, MAXPGPATH, "%s/%s", pg_data,
65  serverVersion < MINIMUM_VERSION_FOR_PG_WAL ? "pg_xlog" : "pg_wal");
66  snprintf(pg_tblspc, MAXPGPATH, "%s/pg_tblspc", pg_data);
67 
68  /*
69  * If pg_wal is a symlink, we'll need to recurse into it separately,
70  * because the first walkdir below will ignore it.
71  */
72  xlog_is_symlink = false;
73 
74 #ifndef WIN32
75  {
76  struct stat st;
77 
78  if (lstat(pg_wal, &st) < 0)
79  pg_log_error("could not stat file \"%s\": %m", pg_wal);
80  else if (S_ISLNK(st.st_mode))
81  xlog_is_symlink = true;
82  }
83 #else
84  if (pgwin32_is_junction(pg_wal))
85  xlog_is_symlink = true;
86 #endif
87 
88  /*
89  * If possible, hint to the kernel that we're soon going to fsync the data
90  * directory and its contents.
91  */
92 #ifdef PG_FLUSH_DATA_WORKS
93  walkdir(pg_data, pre_sync_fname, false);
94  if (xlog_is_symlink)
95  walkdir(pg_wal, pre_sync_fname, false);
96  walkdir(pg_tblspc, pre_sync_fname, true);
97 #endif
98 
99  /*
100  * Now we do the fsync()s in the same order.
101  *
102  * The main call ignores symlinks, so in addition to specially processing
103  * pg_wal if it's a symlink, pg_tblspc has to be visited separately with
104  * process_symlinks = true. Note that if there are any plain directories
105  * in pg_tblspc, they'll get fsync'd twice. That's not an expected case
106  * so we don't worry about optimizing it.
107  */
108  walkdir(pg_data, fsync_fname, false);
109  if (xlog_is_symlink)
110  walkdir(pg_wal, fsync_fname, false);
111  walkdir(pg_tblspc, fsync_fname, true);
112 }
int fsync_fname(const char *fname, bool isdir)
Definition: file_utils.c:255
#define MINIMUM_VERSION_FOR_PG_WAL
Definition: file_utils.c:36
#define pg_log_error(...)
Definition: logging.h:79
static void walkdir(const char *path, int(*action)(const char *fname, bool isdir), bool process_symlinks)
Definition: file_utils.c:148
#define MAXPGPATH
static char * pg_data
Definition: initdb.c:123
#define stat(a, b)
Definition: win32_port.h:255
#define lstat(path, sb)
Definition: win32_port.h:244
#define snprintf
Definition: port.h:193
bool pgwin32_is_junction(const char *path)