PostgreSQL Source Code  git master
fd.c
Go to the documentation of this file.
1 /*-------------------------------------------------------------------------
2  *
3  * fd.c
4  * Virtual file descriptor code.
5  *
6  * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
7  * Portions Copyright (c) 1994, Regents of the University of California
8  *
9  * IDENTIFICATION
10  * src/backend/storage/file/fd.c
11  *
12  * NOTES:
13  *
14  * This code manages a cache of 'virtual' file descriptors (VFDs).
15  * The server opens many file descriptors for a variety of reasons,
16  * including base tables, scratch files (e.g., sort and hash spool
17  * files), and random calls to C library routines like system(3); it
18  * is quite easy to exceed system limits on the number of open files a
19  * single process can have. (This is around 1024 on many modern
20  * operating systems, but may be lower on others.)
21  *
22  * VFDs are managed as an LRU pool, with actual OS file descriptors
23  * being opened and closed as needed. Obviously, if a routine is
24  * opened using these interfaces, all subsequent operations must also
25  * be through these interfaces (the File type is not a real file
26  * descriptor).
27  *
28  * For this scheme to work, most (if not all) routines throughout the
29  * server should use these interfaces instead of calling the C library
30  * routines (e.g., open(2) and fopen(3)) themselves. Otherwise, we
31  * may find ourselves short of real file descriptors anyway.
32  *
33  * INTERFACE ROUTINES
34  *
35  * PathNameOpenFile and OpenTemporaryFile are used to open virtual files.
36  * A File opened with OpenTemporaryFile is automatically deleted when the
37  * File is closed, either explicitly or implicitly at end of transaction or
38  * process exit. PathNameOpenFile is intended for files that are held open
39  * for a long time, like relation files. It is the caller's responsibility
40  * to close them, there is no automatic mechanism in fd.c for that.
41  *
42  * PathName(Create|Open|Delete)Temporary(File|Dir) are used to manage
43  * temporary files that have names so that they can be shared between
44  * backends. Such files are automatically closed and count against the
45  * temporary file limit of the backend that creates them, but unlike anonymous
46  * files they are not automatically deleted. See sharedfileset.c for a shared
47  * ownership mechanism that provides automatic cleanup for shared files when
48  * the last of a group of backends detaches.
49  *
50  * AllocateFile, AllocateDir, OpenPipeStream and OpenTransientFile are
51  * wrappers around fopen(3), opendir(3), popen(3) and open(2), respectively.
52  * They behave like the corresponding native functions, except that the handle
53  * is registered with the current subtransaction, and will be automatically
54  * closed at abort. These are intended mainly for short operations like
55  * reading a configuration file; there is a limit on the number of files that
56  * can be opened using these functions at any one time.
57  *
58  * Finally, BasicOpenFile is just a thin wrapper around open() that can
59  * release file descriptors in use by the virtual file descriptors if
60  * necessary. There is no automatic cleanup of file descriptors returned by
61  * BasicOpenFile, it is solely the caller's responsibility to close the file
62  * descriptor by calling close(2).
63  *
64  * If a non-virtual file descriptor needs to be held open for any length of
65  * time, report it to fd.c by calling AcquireExternalFD or ReserveExternalFD
66  * (and eventually ReleaseExternalFD), so that we can take it into account
67  * while deciding how many VFDs can be open. This applies to FDs obtained
68  * with BasicOpenFile as well as those obtained without use of any fd.c API.
69  *
70  *-------------------------------------------------------------------------
71  */
72 
73 #include "postgres.h"
74 
75 #include <dirent.h>
76 #include <sys/file.h>
77 #include <sys/param.h>
78 #include <sys/resource.h> /* for getrlimit */
79 #include <sys/stat.h>
80 #include <sys/types.h>
81 #ifndef WIN32
82 #include <sys/mman.h>
83 #endif
84 #include <limits.h>
85 #include <unistd.h>
86 #include <fcntl.h>
87 
88 #include "access/xact.h"
89 #include "access/xlog.h"
90 #include "catalog/pg_tablespace.h"
91 #include "common/file_perm.h"
92 #include "common/file_utils.h"
93 #include "common/pg_prng.h"
94 #include "miscadmin.h"
95 #include "pgstat.h"
96 #include "portability/mem.h"
97 #include "postmaster/startup.h"
98 #include "storage/fd.h"
99 #include "storage/ipc.h"
100 #include "utils/guc.h"
101 #include "utils/guc_hooks.h"
102 #include "utils/resowner.h"
103 #include "utils/varlena.h"
104 
105 /* Define PG_FLUSH_DATA_WORKS if we have an implementation for pg_flush_data */
106 #if defined(HAVE_SYNC_FILE_RANGE)
107 #define PG_FLUSH_DATA_WORKS 1
108 #elif !defined(WIN32) && defined(MS_ASYNC)
109 #define PG_FLUSH_DATA_WORKS 1
110 #elif defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_DONTNEED)
111 #define PG_FLUSH_DATA_WORKS 1
112 #endif
113 
114 /*
115  * We must leave some file descriptors free for system(), the dynamic loader,
116  * and other code that tries to open files without consulting fd.c. This
117  * is the number left free. (While we try fairly hard to prevent EMFILE
118  * errors, there's never any guarantee that we won't get ENFILE due to
119  * other processes chewing up FDs. So it's a bad idea to try to open files
120  * without consulting fd.c. Nonetheless we cannot control all code.)
121  *
122  * Because this is just a fixed setting, we are effectively assuming that
123  * no such code will leave FDs open over the long term; otherwise the slop
124  * is likely to be insufficient. Note in particular that we expect that
125  * loading a shared library does not result in any permanent increase in
126  * the number of open files. (This appears to be true on most if not
127  * all platforms as of Feb 2004.)
128  */
129 #define NUM_RESERVED_FDS 10
130 
131 /*
132  * If we have fewer than this many usable FDs after allowing for the reserved
133  * ones, choke. (This value is chosen to work with "ulimit -n 64", but not
134  * much less than that. Note that this value ensures numExternalFDs can be
135  * at least 16; as of this writing, the contrib/postgres_fdw regression tests
136  * will not pass unless that can grow to at least 14.)
137  */
138 #define FD_MINFREE 48
139 
140 /*
141  * A number of platforms allow individual processes to open many more files
142  * than they can really support when *many* processes do the same thing.
143  * This GUC parameter lets the DBA limit max_safe_fds to something less than
144  * what the postmaster's initial probe suggests will work.
145  */
147 
148 /*
149  * Maximum number of file descriptors to open for operations that fd.c knows
150  * about (VFDs, AllocateFile etc, or "external" FDs). This is initialized
151  * to a conservative value, and remains that way indefinitely in bootstrap or
152  * standalone-backend cases. In normal postmaster operation, the postmaster
153  * calls set_max_safe_fds() late in initialization to update the value, and
154  * that value is then inherited by forked subprocesses.
155  *
156  * Note: the value of max_files_per_process is taken into account while
157  * setting this variable, and so need not be tested separately.
158  */
159 int max_safe_fds = FD_MINFREE; /* default if not changed */
160 
161 /* Whether it is safe to continue running after fsync() fails. */
162 bool data_sync_retry = false;
163 
164 /* How SyncDataDirectory() should do its job. */
166 
167 /* Which kinds of files should be opened with PG_O_DIRECT. */
169 
170 /* Debugging.... */
171 
172 #ifdef FDDEBUG
173 #define DO_DB(A) \
174  do { \
175  int _do_db_save_errno = errno; \
176  A; \
177  errno = _do_db_save_errno; \
178  } while (0)
179 #else
180 #define DO_DB(A) \
181  ((void) 0)
182 #endif
183 
184 #define VFD_CLOSED (-1)
185 
186 #define FileIsValid(file) \
187  ((file) > 0 && (file) < (int) SizeVfdCache && VfdCache[file].fileName != NULL)
188 
189 #define FileIsNotOpen(file) (VfdCache[file].fd == VFD_CLOSED)
190 
191 /* these are the assigned bits in fdstate below: */
192 #define FD_DELETE_AT_CLOSE (1 << 0) /* T = delete when closed */
193 #define FD_CLOSE_AT_EOXACT (1 << 1) /* T = close at eoXact */
194 #define FD_TEMP_FILE_LIMIT (1 << 2) /* T = respect temp_file_limit */
195 
196 typedef struct vfd
197 {
198  int fd; /* current FD, or VFD_CLOSED if none */
199  unsigned short fdstate; /* bitflags for VFD's state */
200  ResourceOwner resowner; /* owner, for automatic cleanup */
201  File nextFree; /* link to next free VFD, if in freelist */
202  File lruMoreRecently; /* doubly linked recency-of-use list */
204  off_t fileSize; /* current size of file (0 if not temporary) */
205  char *fileName; /* name of file, or NULL for unused VFD */
206  /* NB: fileName is malloc'd, and must be free'd when closing the VFD */
207  int fileFlags; /* open(2) flags for (re)opening the file */
208  mode_t fileMode; /* mode to pass to open(2) */
209 } Vfd;
210 
211 /*
212  * Virtual File Descriptor array pointer and size. This grows as
213  * needed. 'File' values are indexes into this array.
214  * Note that VfdCache[0] is not a usable VFD, just a list header.
215  */
216 static Vfd *VfdCache;
217 static Size SizeVfdCache = 0;
218 
219 /*
220  * Number of file descriptors known to be in use by VFD entries.
221  */
222 static int nfile = 0;
223 
224 /*
225  * Flag to tell whether it's worth scanning VfdCache looking for temp files
226  * to close
227  */
228 static bool have_xact_temporary_files = false;
229 
230 /*
231  * Tracks the total size of all temporary files. Note: when temp_file_limit
232  * is being enforced, this cannot overflow since the limit cannot be more
233  * than INT_MAX kilobytes. When not enforcing, it could theoretically
234  * overflow, but we don't care.
235  */
236 static uint64 temporary_files_size = 0;
237 
238 /* Temporary file access initialized and not yet shut down? */
239 #ifdef USE_ASSERT_CHECKING
240 static bool temporary_files_allowed = false;
241 #endif
242 
243 /*
244  * List of OS handles opened with AllocateFile, AllocateDir and
245  * OpenTransientFile.
246  */
247 typedef enum
248 {
254 
255 typedef struct
256 {
259  union
260  {
261  FILE *file;
263  int fd;
264  } desc;
265 } AllocateDesc;
266 
267 static int numAllocatedDescs = 0;
268 static int maxAllocatedDescs = 0;
270 
271 /*
272  * Number of open "external" FDs reported to Reserve/ReleaseExternalFD.
273  */
274 static int numExternalFDs = 0;
275 
276 /*
277  * Number of temporary files opened during the current session;
278  * this is used in generation of tempfile names.
279  */
280 static long tempFileCounter = 0;
281 
282 /*
283  * Array of OIDs of temp tablespaces. (Some entries may be InvalidOid,
284  * indicating that the current database's default tablespace should be used.)
285  * When numTempTableSpaces is -1, this has not been set in the current
286  * transaction.
287  */
288 static Oid *tempTableSpaces = NULL;
289 static int numTempTableSpaces = -1;
290 static int nextTempTableSpace = 0;
291 
292 
293 /*--------------------
294  *
295  * Private Routines
296  *
297  * Delete - delete a file from the Lru ring
298  * LruDelete - remove a file from the Lru ring and close its FD
299  * Insert - put a file at the front of the Lru ring
300  * LruInsert - put a file at the front of the Lru ring and open it
301  * ReleaseLruFile - Release an fd by closing the last entry in the Lru ring
302  * ReleaseLruFiles - Release fd(s) until we're under the max_safe_fds limit
303  * AllocateVfd - grab a free (or new) file record (from VfdCache)
304  * FreeVfd - free a file record
305  *
306  * The Least Recently Used ring is a doubly linked list that begins and
307  * ends on element zero. Element zero is special -- it doesn't represent
308  * a file and its "fd" field always == VFD_CLOSED. Element zero is just an
309  * anchor that shows us the beginning/end of the ring.
310  * Only VFD elements that are currently really open (have an FD assigned) are
311  * in the Lru ring. Elements that are "virtually" open can be recognized
312  * by having a non-null fileName field.
313  *
314  * example:
315  *
316  * /--less----\ /---------\
317  * v \ v \
318  * #0 --more---> LeastRecentlyUsed --more-\ \
319  * ^\ | |
320  * \\less--> MostRecentlyUsedFile <---/ |
321  * \more---/ \--less--/
322  *
323  *--------------------
324  */
325 static void Delete(File file);
326 static void LruDelete(File file);
327 static void Insert(File file);
328 static int LruInsert(File file);
329 static bool ReleaseLruFile(void);
330 static void ReleaseLruFiles(void);
331 static File AllocateVfd(void);
332 static void FreeVfd(File file);
333 
334 static int FileAccess(File file);
335 static File OpenTemporaryFileInTablespace(Oid tblspcOid, bool rejectError);
336 static bool reserveAllocatedDesc(void);
337 static int FreeDesc(AllocateDesc *desc);
338 
339 static void BeforeShmemExit_Files(int code, Datum arg);
340 static void CleanupTempFiles(bool isCommit, bool isProcExit);
341 static void RemovePgTempRelationFiles(const char *tsdirname);
342 static void RemovePgTempRelationFilesInDbspace(const char *dbspacedirname);
343 
344 static void walkdir(const char *path,
345  void (*action) (const char *fname, bool isdir, int elevel),
346  bool process_symlinks,
347  int elevel);
348 #ifdef PG_FLUSH_DATA_WORKS
349 static void pre_sync_fname(const char *fname, bool isdir, int elevel);
350 #endif
351 static void datadir_fsync_fname(const char *fname, bool isdir, int elevel);
352 static void unlink_if_exists_fname(const char *fname, bool isdir, int elevel);
353 
354 static int fsync_parent_path(const char *fname, int elevel);
355 
356 
357 /* ResourceOwner callbacks to hold virtual file descriptors */
358 static void ResOwnerReleaseFile(Datum res);
359 static char *ResOwnerPrintFile(Datum res);
360 
362 {
363  .name = "File",
364  .release_phase = RESOURCE_RELEASE_AFTER_LOCKS,
365  .release_priority = RELEASE_PRIO_FILES,
366  .ReleaseResource = ResOwnerReleaseFile,
367  .DebugPrint = ResOwnerPrintFile
368 };
369 
370 /* Convenience wrappers over ResourceOwnerRemember/Forget */
371 static inline void
373 {
375 }
376 static inline void
378 {
380 }
381 
382 /*
383  * pg_fsync --- do fsync with or without writethrough
384  */
385 int
387 {
388 #if !defined(WIN32) && defined(USE_ASSERT_CHECKING)
389  struct stat st;
390 
391  /*
392  * Some operating system implementations of fsync() have requirements
393  * about the file access modes that were used when their file descriptor
394  * argument was opened, and these requirements differ depending on whether
395  * the file descriptor is for a directory.
396  *
397  * For any file descriptor that may eventually be handed to fsync(), we
398  * should have opened it with access modes that are compatible with
399  * fsync() on all supported systems, otherwise the code may not be
400  * portable, even if it runs ok on the current system.
401  *
402  * We assert here that a descriptor for a file was opened with write
403  * permissions (either O_RDWR or O_WRONLY) and for a directory without
404  * write permissions (O_RDONLY).
405  *
406  * Ignore any fstat errors and let the follow-up fsync() do its work.
407  * Doing this sanity check here counts for the case where fsync() is
408  * disabled.
409  */
410  if (fstat(fd, &st) == 0)
411  {
412  int desc_flags = fcntl(fd, F_GETFL);
413 
414  /*
415  * O_RDONLY is historically 0, so just make sure that for directories
416  * no write flags are used.
417  */
418  if (S_ISDIR(st.st_mode))
419  Assert((desc_flags & (O_RDWR | O_WRONLY)) == 0);
420  else
421  Assert((desc_flags & (O_RDWR | O_WRONLY)) != 0);
422  }
423  errno = 0;
424 #endif
425 
426  /* #if is to skip the wal_sync_method test if there's no need for it */
427 #if defined(HAVE_FSYNC_WRITETHROUGH)
429  return pg_fsync_writethrough(fd);
430  else
431 #endif
433 }
434 
435 
436 /*
437  * pg_fsync_no_writethrough --- same as fsync except does nothing if
438  * enableFsync is off
439  */
440 int
442 {
443  int rc;
444 
445  if (!enableFsync)
446  return 0;
447 
448 retry:
449  rc = fsync(fd);
450 
451  if (rc == -1 && errno == EINTR)
452  goto retry;
453 
454  return rc;
455 }
456 
457 /*
458  * pg_fsync_writethrough
459  */
460 int
462 {
463  if (enableFsync)
464  {
465 #if defined(F_FULLFSYNC)
466  return (fcntl(fd, F_FULLFSYNC, 0) == -1) ? -1 : 0;
467 #else
468  errno = ENOSYS;
469  return -1;
470 #endif
471  }
472  else
473  return 0;
474 }
475 
476 /*
477  * pg_fdatasync --- same as fdatasync except does nothing if enableFsync is off
478  */
479 int
481 {
482  int rc;
483 
484  if (!enableFsync)
485  return 0;
486 
487 retry:
488  rc = fdatasync(fd);
489 
490  if (rc == -1 && errno == EINTR)
491  goto retry;
492 
493  return rc;
494 }
495 
496 /*
497  * pg_file_exists -- check that a file exists.
498  *
499  * This requires an absolute path to the file. Returns true if the file is
500  * not a directory, false otherwise.
501  */
502 bool
503 pg_file_exists(const char *name)
504 {
505  struct stat st;
506 
507  Assert(name != NULL);
508 
509  if (stat(name, &st) == 0)
510  return !S_ISDIR(st.st_mode);
511  else if (!(errno == ENOENT || errno == ENOTDIR || errno == EACCES))
512  ereport(ERROR,
514  errmsg("could not access file \"%s\": %m", name)));
515 
516  return false;
517 }
518 
519 /*
520  * pg_flush_data --- advise OS that the described dirty data should be flushed
521  *
522  * offset of 0 with nbytes 0 means that the entire file should be flushed
523  */
524 void
525 pg_flush_data(int fd, off_t offset, off_t nbytes)
526 {
527  /*
528  * Right now file flushing is primarily used to avoid making later
529  * fsync()/fdatasync() calls have less impact. Thus don't trigger flushes
530  * if fsyncs are disabled - that's a decision we might want to make
531  * configurable at some point.
532  */
533  if (!enableFsync)
534  return;
535 
536  /*
537  * We compile all alternatives that are supported on the current platform,
538  * to find portability problems more easily.
539  */
540 #if defined(HAVE_SYNC_FILE_RANGE)
541  {
542  int rc;
543  static bool not_implemented_by_kernel = false;
544 
545  if (not_implemented_by_kernel)
546  return;
547 
548 retry:
549 
550  /*
551  * sync_file_range(SYNC_FILE_RANGE_WRITE), currently linux specific,
552  * tells the OS that writeback for the specified blocks should be
553  * started, but that we don't want to wait for completion. Note that
554  * this call might block if too much dirty data exists in the range.
555  * This is the preferable method on OSs supporting it, as it works
556  * reliably when available (contrast to msync()) and doesn't flush out
557  * clean data (like FADV_DONTNEED).
558  */
559  rc = sync_file_range(fd, offset, nbytes,
560  SYNC_FILE_RANGE_WRITE);
561  if (rc != 0)
562  {
563  int elevel;
564 
565  if (rc == EINTR)
566  goto retry;
567 
568  /*
569  * For systems that don't have an implementation of
570  * sync_file_range() such as Windows WSL, generate only one
571  * warning and then suppress all further attempts by this process.
572  */
573  if (errno == ENOSYS)
574  {
575  elevel = WARNING;
576  not_implemented_by_kernel = true;
577  }
578  else
579  elevel = data_sync_elevel(WARNING);
580 
581  ereport(elevel,
583  errmsg("could not flush dirty data: %m")));
584  }
585 
586  return;
587  }
588 #endif
589 #if !defined(WIN32) && defined(MS_ASYNC)
590  {
591  void *p;
592  static int pagesize = 0;
593 
594  /*
595  * On several OSs msync(MS_ASYNC) on a mmap'ed file triggers
596  * writeback. On linux it only does so if MS_SYNC is specified, but
597  * then it does the writeback synchronously. Luckily all common linux
598  * systems have sync_file_range(). This is preferable over
599  * FADV_DONTNEED because it doesn't flush out clean data.
600  *
601  * We map the file (mmap()), tell the kernel to sync back the contents
602  * (msync()), and then remove the mapping again (munmap()).
603  */
604 
605  /* mmap() needs actual length if we want to map whole file */
606  if (offset == 0 && nbytes == 0)
607  {
608  nbytes = lseek(fd, 0, SEEK_END);
609  if (nbytes < 0)
610  {
613  errmsg("could not determine dirty data size: %m")));
614  return;
615  }
616  }
617 
618  /*
619  * Some platforms reject partial-page mmap() attempts. To deal with
620  * that, just truncate the request to a page boundary. If any extra
621  * bytes don't get flushed, well, it's only a hint anyway.
622  */
623 
624  /* fetch pagesize only once */
625  if (pagesize == 0)
626  pagesize = sysconf(_SC_PAGESIZE);
627 
628  /* align length to pagesize, dropping any fractional page */
629  if (pagesize > 0)
630  nbytes = (nbytes / pagesize) * pagesize;
631 
632  /* fractional-page request is a no-op */
633  if (nbytes <= 0)
634  return;
635 
636  /*
637  * mmap could well fail, particularly on 32-bit platforms where there
638  * may simply not be enough address space. If so, silently fall
639  * through to the next implementation.
640  */
641  if (nbytes <= (off_t) SSIZE_MAX)
642  p = mmap(NULL, nbytes, PROT_READ, MAP_SHARED, fd, offset);
643  else
644  p = MAP_FAILED;
645 
646  if (p != MAP_FAILED)
647  {
648  int rc;
649 
650  rc = msync(p, (size_t) nbytes, MS_ASYNC);
651  if (rc != 0)
652  {
655  errmsg("could not flush dirty data: %m")));
656  /* NB: need to fall through to munmap()! */
657  }
658 
659  rc = munmap(p, (size_t) nbytes);
660  if (rc != 0)
661  {
662  /* FATAL error because mapping would remain */
663  ereport(FATAL,
665  errmsg("could not munmap() while flushing data: %m")));
666  }
667 
668  return;
669  }
670  }
671 #endif
672 #if defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_DONTNEED)
673  {
674  int rc;
675 
676  /*
677  * Signal the kernel that the passed in range should not be cached
678  * anymore. This has the, desired, side effect of writing out dirty
679  * data, and the, undesired, side effect of likely discarding useful
680  * clean cached blocks. For the latter reason this is the least
681  * preferable method.
682  */
683 
684  rc = posix_fadvise(fd, offset, nbytes, POSIX_FADV_DONTNEED);
685 
686  if (rc != 0)
687  {
688  /* don't error out, this is just a performance optimization */
691  errmsg("could not flush dirty data: %m")));
692  }
693 
694  return;
695  }
696 #endif
697 }
698 
699 /*
700  * Truncate an open file to a given length.
701  */
702 static int
703 pg_ftruncate(int fd, off_t length)
704 {
705  int ret;
706 
707 retry:
708  ret = ftruncate(fd, length);
709 
710  if (ret == -1 && errno == EINTR)
711  goto retry;
712 
713  return ret;
714 }
715 
716 /*
717  * Truncate a file to a given length by name.
718  */
719 int
720 pg_truncate(const char *path, off_t length)
721 {
722  int ret;
723 #ifdef WIN32
724  int save_errno;
725  int fd;
726 
727  fd = OpenTransientFile(path, O_RDWR | PG_BINARY);
728  if (fd >= 0)
729  {
730  ret = pg_ftruncate(fd, length);
731  save_errno = errno;
733  errno = save_errno;
734  }
735  else
736  ret = -1;
737 #else
738 
739 retry:
740  ret = truncate(path, length);
741 
742  if (ret == -1 && errno == EINTR)
743  goto retry;
744 #endif
745 
746  return ret;
747 }
748 
749 /*
750  * fsync_fname -- fsync a file or directory, handling errors properly
751  *
752  * Try to fsync a file or directory. When doing the latter, ignore errors that
753  * indicate the OS just doesn't allow/require fsyncing directories.
754  */
755 void
756 fsync_fname(const char *fname, bool isdir)
757 {
758  fsync_fname_ext(fname, isdir, false, data_sync_elevel(ERROR));
759 }
760 
761 /*
762  * durable_rename -- rename(2) wrapper, issuing fsyncs required for durability
763  *
764  * This routine ensures that, after returning, the effect of renaming file
765  * persists in case of a crash. A crash while this routine is running will
766  * leave you with either the pre-existing or the moved file in place of the
767  * new file; no mixed state or truncated files are possible.
768  *
769  * It does so by using fsync on the old filename and the possibly existing
770  * target filename before the rename, and the target file and directory after.
771  *
772  * Note that rename() cannot be used across arbitrary directories, as they
773  * might not be on the same filesystem. Therefore this routine does not
774  * support renaming across directories.
775  *
776  * Log errors with the caller specified severity.
777  *
778  * Returns 0 if the operation succeeded, -1 otherwise. Note that errno is not
779  * valid upon return.
780  */
781 int
782 durable_rename(const char *oldfile, const char *newfile, int elevel)
783 {
784  int fd;
785 
786  /*
787  * First fsync the old and target path (if it exists), to ensure that they
788  * are properly persistent on disk. Syncing the target file is not
789  * strictly necessary, but it makes it easier to reason about crashes;
790  * because it's then guaranteed that either source or target file exists
791  * after a crash.
792  */
793  if (fsync_fname_ext(oldfile, false, false, elevel) != 0)
794  return -1;
795 
796  fd = OpenTransientFile(newfile, PG_BINARY | O_RDWR);
797  if (fd < 0)
798  {
799  if (errno != ENOENT)
800  {
801  ereport(elevel,
803  errmsg("could not open file \"%s\": %m", newfile)));
804  return -1;
805  }
806  }
807  else
808  {
809  if (pg_fsync(fd) != 0)
810  {
811  int save_errno;
812 
813  /* close file upon error, might not be in transaction context */
814  save_errno = errno;
816  errno = save_errno;
817 
818  ereport(elevel,
820  errmsg("could not fsync file \"%s\": %m", newfile)));
821  return -1;
822  }
823 
824  if (CloseTransientFile(fd) != 0)
825  {
826  ereport(elevel,
828  errmsg("could not close file \"%s\": %m", newfile)));
829  return -1;
830  }
831  }
832 
833  /* Time to do the real deal... */
834  if (rename(oldfile, newfile) < 0)
835  {
836  ereport(elevel,
838  errmsg("could not rename file \"%s\" to \"%s\": %m",
839  oldfile, newfile)));
840  return -1;
841  }
842 
843  /*
844  * To guarantee renaming the file is persistent, fsync the file with its
845  * new name, and its containing directory.
846  */
847  if (fsync_fname_ext(newfile, false, false, elevel) != 0)
848  return -1;
849 
850  if (fsync_parent_path(newfile, elevel) != 0)
851  return -1;
852 
853  return 0;
854 }
855 
856 /*
857  * durable_unlink -- remove a file in a durable manner
858  *
859  * This routine ensures that, after returning, the effect of removing file
860  * persists in case of a crash. A crash while this routine is running will
861  * leave the system in no mixed state.
862  *
863  * It does so by using fsync on the parent directory of the file after the
864  * actual removal is done.
865  *
866  * Log errors with the severity specified by caller.
867  *
868  * Returns 0 if the operation succeeded, -1 otherwise. Note that errno is not
869  * valid upon return.
870  */
871 int
872 durable_unlink(const char *fname, int elevel)
873 {
874  if (unlink(fname) < 0)
875  {
876  ereport(elevel,
878  errmsg("could not remove file \"%s\": %m",
879  fname)));
880  return -1;
881  }
882 
883  /*
884  * To guarantee that the removal of the file is persistent, fsync its
885  * parent directory.
886  */
887  if (fsync_parent_path(fname, elevel) != 0)
888  return -1;
889 
890  return 0;
891 }
892 
893 /*
894  * InitFileAccess --- initialize this module during backend startup
895  *
896  * This is called during either normal or standalone backend start.
897  * It is *not* called in the postmaster.
898  *
899  * Note that this does not initialize temporary file access, that is
900  * separately initialized via InitTemporaryFileAccess().
901  */
902 void
904 {
905  Assert(SizeVfdCache == 0); /* call me only once */
906 
907  /* initialize cache header entry */
908  VfdCache = (Vfd *) malloc(sizeof(Vfd));
909  if (VfdCache == NULL)
910  ereport(FATAL,
911  (errcode(ERRCODE_OUT_OF_MEMORY),
912  errmsg("out of memory")));
913 
914  MemSet((char *) &(VfdCache[0]), 0, sizeof(Vfd));
916 
917  SizeVfdCache = 1;
918 }
919 
920 /*
921  * InitTemporaryFileAccess --- initialize temporary file access during startup
922  *
923  * This is called during either normal or standalone backend start.
924  * It is *not* called in the postmaster.
925  *
926  * This is separate from InitFileAccess() because temporary file cleanup can
927  * cause pgstat reporting. As pgstat is shut down during before_shmem_exit(),
928  * our reporting has to happen before that. Low level file access should be
929  * available for longer, hence the separate initialization / shutdown of
930  * temporary file handling.
931  */
932 void
934 {
935  Assert(SizeVfdCache != 0); /* InitFileAccess() needs to have run */
936  Assert(!temporary_files_allowed); /* call me only once */
937 
938  /*
939  * Register before-shmem-exit hook to ensure temp files are dropped while
940  * we can still report stats.
941  */
943 
944 #ifdef USE_ASSERT_CHECKING
945  temporary_files_allowed = true;
946 #endif
947 }
948 
949 /*
950  * count_usable_fds --- count how many FDs the system will let us open,
951  * and estimate how many are already open.
952  *
953  * We stop counting if usable_fds reaches max_to_probe. Note: a small
954  * value of max_to_probe might result in an underestimate of already_open;
955  * we must fill in any "gaps" in the set of used FDs before the calculation
956  * of already_open will give the right answer. In practice, max_to_probe
957  * of a couple of dozen should be enough to ensure good results.
958  *
959  * We assume stderr (FD 2) is available for dup'ing. While the calling
960  * script could theoretically close that, it would be a really bad idea,
961  * since then one risks loss of error messages from, e.g., libc.
962  */
963 static void
964 count_usable_fds(int max_to_probe, int *usable_fds, int *already_open)
965 {
966  int *fd;
967  int size;
968  int used = 0;
969  int highestfd = 0;
970  int j;
971 
972 #ifdef HAVE_GETRLIMIT
973  struct rlimit rlim;
974  int getrlimit_status;
975 #endif
976 
977  size = 1024;
978  fd = (int *) palloc(size * sizeof(int));
979 
980 #ifdef HAVE_GETRLIMIT
981  getrlimit_status = getrlimit(RLIMIT_NOFILE, &rlim);
982  if (getrlimit_status != 0)
983  ereport(WARNING, (errmsg("getrlimit failed: %m")));
984 #endif /* HAVE_GETRLIMIT */
985 
986  /* dup until failure or probe limit reached */
987  for (;;)
988  {
989  int thisfd;
990 
991 #ifdef HAVE_GETRLIMIT
992 
993  /*
994  * don't go beyond RLIMIT_NOFILE; causes irritating kernel logs on
995  * some platforms
996  */
997  if (getrlimit_status == 0 && highestfd >= rlim.rlim_cur - 1)
998  break;
999 #endif
1000 
1001  thisfd = dup(2);
1002  if (thisfd < 0)
1003  {
1004  /* Expect EMFILE or ENFILE, else it's fishy */
1005  if (errno != EMFILE && errno != ENFILE)
1006  elog(WARNING, "duplicating stderr file descriptor failed after %d successes: %m", used);
1007  break;
1008  }
1009 
1010  if (used >= size)
1011  {
1012  size *= 2;
1013  fd = (int *) repalloc(fd, size * sizeof(int));
1014  }
1015  fd[used++] = thisfd;
1016 
1017  if (highestfd < thisfd)
1018  highestfd = thisfd;
1019 
1020  if (used >= max_to_probe)
1021  break;
1022  }
1023 
1024  /* release the files we opened */
1025  for (j = 0; j < used; j++)
1026  close(fd[j]);
1027 
1028  pfree(fd);
1029 
1030  /*
1031  * Return results. usable_fds is just the number of successful dups. We
1032  * assume that the system limit is highestfd+1 (remember 0 is a legal FD
1033  * number) and so already_open is highestfd+1 - usable_fds.
1034  */
1035  *usable_fds = used;
1036  *already_open = highestfd + 1 - used;
1037 }
1038 
1039 /*
1040  * set_max_safe_fds
1041  * Determine number of file descriptors that fd.c is allowed to use
1042  */
1043 void
1045 {
1046  int usable_fds;
1047  int already_open;
1048 
1049  /*----------
1050  * We want to set max_safe_fds to
1051  * MIN(usable_fds, max_files_per_process - already_open)
1052  * less the slop factor for files that are opened without consulting
1053  * fd.c. This ensures that we won't exceed either max_files_per_process
1054  * or the experimentally-determined EMFILE limit.
1055  *----------
1056  */
1058  &usable_fds, &already_open);
1059 
1060  max_safe_fds = Min(usable_fds, max_files_per_process - already_open);
1061 
1062  /*
1063  * Take off the FDs reserved for system() etc.
1064  */
1066 
1067  /*
1068  * Make sure we still have enough to get by.
1069  */
1070  if (max_safe_fds < FD_MINFREE)
1071  ereport(FATAL,
1072  (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
1073  errmsg("insufficient file descriptors available to start server process"),
1074  errdetail("System allows %d, server needs at least %d.",
1077 
1078  elog(DEBUG2, "max_safe_fds = %d, usable_fds = %d, already_open = %d",
1079  max_safe_fds, usable_fds, already_open);
1080 }
1081 
1082 /*
1083  * Open a file with BasicOpenFilePerm() and pass default file mode for the
1084  * fileMode parameter.
1085  */
1086 int
1087 BasicOpenFile(const char *fileName, int fileFlags)
1088 {
1089  return BasicOpenFilePerm(fileName, fileFlags, pg_file_create_mode);
1090 }
1091 
1092 /*
1093  * BasicOpenFilePerm --- same as open(2) except can free other FDs if needed
1094  *
1095  * This is exported for use by places that really want a plain kernel FD,
1096  * but need to be proof against running out of FDs. Once an FD has been
1097  * successfully returned, it is the caller's responsibility to ensure that
1098  * it will not be leaked on ereport()! Most users should *not* call this
1099  * routine directly, but instead use the VFD abstraction level, which
1100  * provides protection against descriptor leaks as well as management of
1101  * files that need to be open for more than a short period of time.
1102  *
1103  * Ideally this should be the *only* direct call of open() in the backend.
1104  * In practice, the postmaster calls open() directly, and there are some
1105  * direct open() calls done early in backend startup. Those are OK since
1106  * this module wouldn't have any open files to close at that point anyway.
1107  */
1108 int
1109 BasicOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode)
1110 {
1111  int fd;
1112 
1113 tryAgain:
1114 #ifdef PG_O_DIRECT_USE_F_NOCACHE
1115 
1116  /*
1117  * The value we defined to stand in for O_DIRECT when simulating it with
1118  * F_NOCACHE had better not collide with any of the standard flags.
1119  */
1121  (O_APPEND |
1122  O_CLOEXEC |
1123  O_CREAT |
1124  O_DSYNC |
1125  O_EXCL |
1126  O_RDWR |
1127  O_RDONLY |
1128  O_SYNC |
1129  O_TRUNC |
1130  O_WRONLY)) == 0,
1131  "PG_O_DIRECT value collides with standard flag");
1132  fd = open(fileName, fileFlags & ~PG_O_DIRECT, fileMode);
1133 #else
1134  fd = open(fileName, fileFlags, fileMode);
1135 #endif
1136 
1137  if (fd >= 0)
1138  {
1139 #ifdef PG_O_DIRECT_USE_F_NOCACHE
1140  if (fileFlags & PG_O_DIRECT)
1141  {
1142  if (fcntl(fd, F_NOCACHE, 1) < 0)
1143  {
1144  int save_errno = errno;
1145 
1146  close(fd);
1147  errno = save_errno;
1148  return -1;
1149  }
1150  }
1151 #endif
1152 
1153  return fd; /* success! */
1154  }
1155 
1156  if (errno == EMFILE || errno == ENFILE)
1157  {
1158  int save_errno = errno;
1159 
1160  ereport(LOG,
1161  (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
1162  errmsg("out of file descriptors: %m; release and retry")));
1163  errno = 0;
1164  if (ReleaseLruFile())
1165  goto tryAgain;
1166  errno = save_errno;
1167  }
1168 
1169  return -1; /* failure */
1170 }
1171 
1172 /*
1173  * AcquireExternalFD - attempt to reserve an external file descriptor
1174  *
1175  * This should be used by callers that need to hold a file descriptor open
1176  * over more than a short interval, but cannot use any of the other facilities
1177  * provided by this module.
1178  *
1179  * The difference between this and the underlying ReserveExternalFD function
1180  * is that this will report failure (by setting errno and returning false)
1181  * if "too many" external FDs are already reserved. This should be used in
1182  * any code where the total number of FDs to be reserved is not predictable
1183  * and small.
1184  */
1185 bool
1187 {
1188  /*
1189  * We don't want more than max_safe_fds / 3 FDs to be consumed for
1190  * "external" FDs.
1191  */
1192  if (numExternalFDs < max_safe_fds / 3)
1193  {
1195  return true;
1196  }
1197  errno = EMFILE;
1198  return false;
1199 }
1200 
1201 /*
1202  * ReserveExternalFD - report external consumption of a file descriptor
1203  *
1204  * This should be used by callers that need to hold a file descriptor open
1205  * over more than a short interval, but cannot use any of the other facilities
1206  * provided by this module. This just tracks the use of the FD and closes
1207  * VFDs if needed to ensure we keep NUM_RESERVED_FDS FDs available.
1208  *
1209  * Call this directly only in code where failure to reserve the FD would be
1210  * fatal; for example, the WAL-writing code does so, since the alternative is
1211  * session failure. Also, it's very unwise to do so in code that could
1212  * consume more than one FD per process.
1213  *
1214  * Note: as long as everybody plays nice so that NUM_RESERVED_FDS FDs remain
1215  * available, it doesn't matter too much whether this is called before or
1216  * after actually opening the FD; but doing so beforehand reduces the risk of
1217  * an EMFILE failure if not everybody played nice. In any case, it's solely
1218  * caller's responsibility to keep the external-FD count in sync with reality.
1219  */
1220 void
1222 {
1223  /*
1224  * Release VFDs if needed to stay safe. Because we do this before
1225  * incrementing numExternalFDs, the final state will be as desired, i.e.,
1226  * nfile + numAllocatedDescs + numExternalFDs <= max_safe_fds.
1227  */
1228  ReleaseLruFiles();
1229 
1230  numExternalFDs++;
1231 }
1232 
1233 /*
1234  * ReleaseExternalFD - report release of an external file descriptor
1235  *
1236  * This is guaranteed not to change errno, so it can be used in failure paths.
1237  */
1238 void
1240 {
1241  Assert(numExternalFDs > 0);
1242  numExternalFDs--;
1243 }
1244 
1245 
1246 #if defined(FDDEBUG)
1247 
1248 static void
1249 _dump_lru(void)
1250 {
1251  int mru = VfdCache[0].lruLessRecently;
1252  Vfd *vfdP = &VfdCache[mru];
1253  char buf[2048];
1254 
1255  snprintf(buf, sizeof(buf), "LRU: MOST %d ", mru);
1256  while (mru != 0)
1257  {
1258  mru = vfdP->lruLessRecently;
1259  vfdP = &VfdCache[mru];
1260  snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "%d ", mru);
1261  }
1262  snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "LEAST");
1263  elog(LOG, "%s", buf);
1264 }
1265 #endif /* FDDEBUG */
1266 
1267 static void
1269 {
1270  Vfd *vfdP;
1271 
1272  Assert(file != 0);
1273 
1274  DO_DB(elog(LOG, "Delete %d (%s)",
1275  file, VfdCache[file].fileName));
1276  DO_DB(_dump_lru());
1277 
1278  vfdP = &VfdCache[file];
1279 
1282 
1283  DO_DB(_dump_lru());
1284 }
1285 
1286 static void
1288 {
1289  Vfd *vfdP;
1290 
1291  Assert(file != 0);
1292 
1293  DO_DB(elog(LOG, "LruDelete %d (%s)",
1294  file, VfdCache[file].fileName));
1295 
1296  vfdP = &VfdCache[file];
1297 
1298  /*
1299  * Close the file. We aren't expecting this to fail; if it does, better
1300  * to leak the FD than to mess up our internal state.
1301  */
1302  if (close(vfdP->fd) != 0)
1304  "could not close file \"%s\": %m", vfdP->fileName);
1305  vfdP->fd = VFD_CLOSED;
1306  --nfile;
1307 
1308  /* delete the vfd record from the LRU ring */
1309  Delete(file);
1310 }
1311 
1312 static void
1314 {
1315  Vfd *vfdP;
1316 
1317  Assert(file != 0);
1318 
1319  DO_DB(elog(LOG, "Insert %d (%s)",
1320  file, VfdCache[file].fileName));
1321  DO_DB(_dump_lru());
1322 
1323  vfdP = &VfdCache[file];
1324 
1325  vfdP->lruMoreRecently = 0;
1327  VfdCache[0].lruLessRecently = file;
1329 
1330  DO_DB(_dump_lru());
1331 }
1332 
1333 /* returns 0 on success, -1 on re-open failure (with errno set) */
1334 static int
1336 {
1337  Vfd *vfdP;
1338 
1339  Assert(file != 0);
1340 
1341  DO_DB(elog(LOG, "LruInsert %d (%s)",
1342  file, VfdCache[file].fileName));
1343 
1344  vfdP = &VfdCache[file];
1345 
1346  if (FileIsNotOpen(file))
1347  {
1348  /* Close excess kernel FDs. */
1349  ReleaseLruFiles();
1350 
1351  /*
1352  * The open could still fail for lack of file descriptors, eg due to
1353  * overall system file table being full. So, be prepared to release
1354  * another FD if necessary...
1355  */
1356  vfdP->fd = BasicOpenFilePerm(vfdP->fileName, vfdP->fileFlags,
1357  vfdP->fileMode);
1358  if (vfdP->fd < 0)
1359  {
1360  DO_DB(elog(LOG, "re-open failed: %m"));
1361  return -1;
1362  }
1363  else
1364  {
1365  ++nfile;
1366  }
1367  }
1368 
1369  /*
1370  * put it at the head of the Lru ring
1371  */
1372 
1373  Insert(file);
1374 
1375  return 0;
1376 }
1377 
1378 /*
1379  * Release one kernel FD by closing the least-recently-used VFD.
1380  */
1381 static bool
1383 {
1384  DO_DB(elog(LOG, "ReleaseLruFile. Opened %d", nfile));
1385 
1386  if (nfile > 0)
1387  {
1388  /*
1389  * There are opened files and so there should be at least one used vfd
1390  * in the ring.
1391  */
1392  Assert(VfdCache[0].lruMoreRecently != 0);
1393  LruDelete(VfdCache[0].lruMoreRecently);
1394  return true; /* freed a file */
1395  }
1396  return false; /* no files available to free */
1397 }
1398 
1399 /*
1400  * Release kernel FDs as needed to get under the max_safe_fds limit.
1401  * After calling this, it's OK to try to open another file.
1402  */
1403 static void
1405 {
1407  {
1408  if (!ReleaseLruFile())
1409  break;
1410  }
1411 }
1412 
1413 static File
1415 {
1416  Index i;
1417  File file;
1418 
1419  DO_DB(elog(LOG, "AllocateVfd. Size %zu", SizeVfdCache));
1420 
1421  Assert(SizeVfdCache > 0); /* InitFileAccess not called? */
1422 
1423  if (VfdCache[0].nextFree == 0)
1424  {
1425  /*
1426  * The free list is empty so it is time to increase the size of the
1427  * array. We choose to double it each time this happens. However,
1428  * there's not much point in starting *real* small.
1429  */
1430  Size newCacheSize = SizeVfdCache * 2;
1431  Vfd *newVfdCache;
1432 
1433  if (newCacheSize < 32)
1434  newCacheSize = 32;
1435 
1436  /*
1437  * Be careful not to clobber VfdCache ptr if realloc fails.
1438  */
1439  newVfdCache = (Vfd *) realloc(VfdCache, sizeof(Vfd) * newCacheSize);
1440  if (newVfdCache == NULL)
1441  ereport(ERROR,
1442  (errcode(ERRCODE_OUT_OF_MEMORY),
1443  errmsg("out of memory")));
1444  VfdCache = newVfdCache;
1445 
1446  /*
1447  * Initialize the new entries and link them into the free list.
1448  */
1449  for (i = SizeVfdCache; i < newCacheSize; i++)
1450  {
1451  MemSet((char *) &(VfdCache[i]), 0, sizeof(Vfd));
1452  VfdCache[i].nextFree = i + 1;
1453  VfdCache[i].fd = VFD_CLOSED;
1454  }
1455  VfdCache[newCacheSize - 1].nextFree = 0;
1457 
1458  /*
1459  * Record the new size
1460  */
1461  SizeVfdCache = newCacheSize;
1462  }
1463 
1464  file = VfdCache[0].nextFree;
1465 
1466  VfdCache[0].nextFree = VfdCache[file].nextFree;
1467 
1468  return file;
1469 }
1470 
1471 static void
1473 {
1474  Vfd *vfdP = &VfdCache[file];
1475 
1476  DO_DB(elog(LOG, "FreeVfd: %d (%s)",
1477  file, vfdP->fileName ? vfdP->fileName : ""));
1478 
1479  if (vfdP->fileName != NULL)
1480  {
1481  free(vfdP->fileName);
1482  vfdP->fileName = NULL;
1483  }
1484  vfdP->fdstate = 0x0;
1485 
1486  vfdP->nextFree = VfdCache[0].nextFree;
1487  VfdCache[0].nextFree = file;
1488 }
1489 
1490 /* returns 0 on success, -1 on re-open failure (with errno set) */
1491 static int
1493 {
1494  int returnValue;
1495 
1496  DO_DB(elog(LOG, "FileAccess %d (%s)",
1497  file, VfdCache[file].fileName));
1498 
1499  /*
1500  * Is the file open? If not, open it and put it at the head of the LRU
1501  * ring (possibly closing the least recently used file to get an FD).
1502  */
1503 
1504  if (FileIsNotOpen(file))
1505  {
1506  returnValue = LruInsert(file);
1507  if (returnValue != 0)
1508  return returnValue;
1509  }
1510  else if (VfdCache[0].lruLessRecently != file)
1511  {
1512  /*
1513  * We now know that the file is open and that it is not the last one
1514  * accessed, so we need to move it to the head of the Lru ring.
1515  */
1516 
1517  Delete(file);
1518  Insert(file);
1519  }
1520 
1521  return 0;
1522 }
1523 
1524 /*
1525  * Called whenever a temporary file is deleted to report its size.
1526  */
1527 static void
1528 ReportTemporaryFileUsage(const char *path, off_t size)
1529 {
1531 
1532  if (log_temp_files >= 0)
1533  {
1534  if ((size / 1024) >= log_temp_files)
1535  ereport(LOG,
1536  (errmsg("temporary file: path \"%s\", size %lu",
1537  path, (unsigned long) size)));
1538  }
1539 }
1540 
1541 /*
1542  * Called to register a temporary file for automatic close.
1543  * ResourceOwnerEnlarge(CurrentResourceOwner) must have been called
1544  * before the file was opened.
1545  */
1546 static void
1548 {
1551 
1552  /* Backup mechanism for closing at end of xact. */
1555 }
1556 
1557 /*
1558  * Called when we get a shared invalidation message on some relation.
1559  */
1560 #ifdef NOT_USED
1561 void
1562 FileInvalidate(File file)
1563 {
1564  Assert(FileIsValid(file));
1565  if (!FileIsNotOpen(file))
1566  LruDelete(file);
1567 }
1568 #endif
1569 
1570 /*
1571  * Open a file with PathNameOpenFilePerm() and pass default file mode for the
1572  * fileMode parameter.
1573  */
1574 File
1575 PathNameOpenFile(const char *fileName, int fileFlags)
1576 {
1577  return PathNameOpenFilePerm(fileName, fileFlags, pg_file_create_mode);
1578 }
1579 
1580 /*
1581  * open a file in an arbitrary directory
1582  *
1583  * NB: if the passed pathname is relative (which it usually is),
1584  * it will be interpreted relative to the process' working directory
1585  * (which should always be $PGDATA when this code is running).
1586  */
1587 File
1588 PathNameOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode)
1589 {
1590  char *fnamecopy;
1591  File file;
1592  Vfd *vfdP;
1593 
1594  DO_DB(elog(LOG, "PathNameOpenFilePerm: %s %x %o",
1595  fileName, fileFlags, fileMode));
1596 
1597  /*
1598  * We need a malloc'd copy of the file name; fail cleanly if no room.
1599  */
1600  fnamecopy = strdup(fileName);
1601  if (fnamecopy == NULL)
1602  ereport(ERROR,
1603  (errcode(ERRCODE_OUT_OF_MEMORY),
1604  errmsg("out of memory")));
1605 
1606  file = AllocateVfd();
1607  vfdP = &VfdCache[file];
1608 
1609  /* Close excess kernel FDs. */
1610  ReleaseLruFiles();
1611 
1612  /*
1613  * Descriptors managed by VFDs are implicitly marked O_CLOEXEC. The
1614  * client shouldn't be expected to know which kernel descriptors are
1615  * currently open, so it wouldn't make sense for them to be inherited by
1616  * executed subprograms.
1617  */
1618  fileFlags |= O_CLOEXEC;
1619 
1620  vfdP->fd = BasicOpenFilePerm(fileName, fileFlags, fileMode);
1621 
1622  if (vfdP->fd < 0)
1623  {
1624  int save_errno = errno;
1625 
1626  FreeVfd(file);
1627  free(fnamecopy);
1628  errno = save_errno;
1629  return -1;
1630  }
1631  ++nfile;
1632  DO_DB(elog(LOG, "PathNameOpenFile: success %d",
1633  vfdP->fd));
1634 
1635  vfdP->fileName = fnamecopy;
1636  /* Saved flags are adjusted to be OK for re-opening file */
1637  vfdP->fileFlags = fileFlags & ~(O_CREAT | O_TRUNC | O_EXCL);
1638  vfdP->fileMode = fileMode;
1639  vfdP->fileSize = 0;
1640  vfdP->fdstate = 0x0;
1641  vfdP->resowner = NULL;
1642 
1643  Insert(file);
1644 
1645  return file;
1646 }
1647 
1648 /*
1649  * Create directory 'directory'. If necessary, create 'basedir', which must
1650  * be the directory above it. This is designed for creating the top-level
1651  * temporary directory on demand before creating a directory underneath it.
1652  * Do nothing if the directory already exists.
1653  *
1654  * Directories created within the top-level temporary directory should begin
1655  * with PG_TEMP_FILE_PREFIX, so that they can be identified as temporary and
1656  * deleted at startup by RemovePgTempFiles(). Further subdirectories below
1657  * that do not need any particular prefix.
1658 */
1659 void
1661 {
1662  if (MakePGDirectory(directory) < 0)
1663  {
1664  if (errno == EEXIST)
1665  return;
1666 
1667  /*
1668  * Failed. Try to create basedir first in case it's missing. Tolerate
1669  * EEXIST to close a race against another process following the same
1670  * algorithm.
1671  */
1672  if (MakePGDirectory(basedir) < 0 && errno != EEXIST)
1673  ereport(ERROR,
1675  errmsg("cannot create temporary directory \"%s\": %m",
1676  basedir)));
1677 
1678  /* Try again. */
1679  if (MakePGDirectory(directory) < 0 && errno != EEXIST)
1680  ereport(ERROR,
1682  errmsg("cannot create temporary subdirectory \"%s\": %m",
1683  directory)));
1684  }
1685 }
1686 
1687 /*
1688  * Delete a directory and everything in it, if it exists.
1689  */
1690 void
1691 PathNameDeleteTemporaryDir(const char *dirname)
1692 {
1693  struct stat statbuf;
1694 
1695  /* Silently ignore missing directory. */
1696  if (stat(dirname, &statbuf) != 0 && errno == ENOENT)
1697  return;
1698 
1699  /*
1700  * Currently, walkdir doesn't offer a way for our passed in function to
1701  * maintain state. Perhaps it should, so that we could tell the caller
1702  * whether this operation succeeded or failed. Since this operation is
1703  * used in a cleanup path, we wouldn't actually behave differently: we'll
1704  * just log failures.
1705  */
1706  walkdir(dirname, unlink_if_exists_fname, false, LOG);
1707 }
1708 
1709 /*
1710  * Open a temporary file that will disappear when we close it.
1711  *
1712  * This routine takes care of generating an appropriate tempfile name.
1713  * There's no need to pass in fileFlags or fileMode either, since only
1714  * one setting makes any sense for a temp file.
1715  *
1716  * Unless interXact is true, the file is remembered by CurrentResourceOwner
1717  * to ensure it's closed and deleted when it's no longer needed, typically at
1718  * the end-of-transaction. In most cases, you don't want temporary files to
1719  * outlive the transaction that created them, so this should be false -- but
1720  * if you need "somewhat" temporary storage, this might be useful. In either
1721  * case, the file is removed when the File is explicitly closed.
1722  */
1723 File
1724 OpenTemporaryFile(bool interXact)
1725 {
1726  File file = 0;
1727 
1728  Assert(temporary_files_allowed); /* check temp file access is up */
1729 
1730  /*
1731  * Make sure the current resource owner has space for this File before we
1732  * open it, if we'll be registering it below.
1733  */
1734  if (!interXact)
1736 
1737  /*
1738  * If some temp tablespace(s) have been given to us, try to use the next
1739  * one. If a given tablespace can't be found, we silently fall back to
1740  * the database's default tablespace.
1741  *
1742  * BUT: if the temp file is slated to outlive the current transaction,
1743  * force it into the database's default tablespace, so that it will not
1744  * pose a threat to possible tablespace drop attempts.
1745  */
1746  if (numTempTableSpaces > 0 && !interXact)
1747  {
1748  Oid tblspcOid = GetNextTempTableSpace();
1749 
1750  if (OidIsValid(tblspcOid))
1751  file = OpenTemporaryFileInTablespace(tblspcOid, false);
1752  }
1753 
1754  /*
1755  * If not, or if tablespace is bad, create in database's default
1756  * tablespace. MyDatabaseTableSpace should normally be set before we get
1757  * here, but just in case it isn't, fall back to pg_default tablespace.
1758  */
1759  if (file <= 0)
1762  DEFAULTTABLESPACE_OID,
1763  true);
1764 
1765  /* Mark it for deletion at close and temporary file size limit */
1767 
1768  /* Register it with the current resource owner */
1769  if (!interXact)
1770  RegisterTemporaryFile(file);
1771 
1772  return file;
1773 }
1774 
1775 /*
1776  * Return the path of the temp directory in a given tablespace.
1777  */
1778 void
1780 {
1781  /*
1782  * Identify the tempfile directory for this tablespace.
1783  *
1784  * If someone tries to specify pg_global, use pg_default instead.
1785  */
1786  if (tablespace == InvalidOid ||
1787  tablespace == DEFAULTTABLESPACE_OID ||
1788  tablespace == GLOBALTABLESPACE_OID)
1789  snprintf(path, MAXPGPATH, "base/%s", PG_TEMP_FILES_DIR);
1790  else
1791  {
1792  /* All other tablespaces are accessed via symlinks */
1793  snprintf(path, MAXPGPATH, "pg_tblspc/%u/%s/%s",
1796  }
1797 }
1798 
1799 /*
1800  * Open a temporary file in a specific tablespace.
1801  * Subroutine for OpenTemporaryFile, which see for details.
1802  */
1803 static File
1804 OpenTemporaryFileInTablespace(Oid tblspcOid, bool rejectError)
1805 {
1806  char tempdirpath[MAXPGPATH];
1807  char tempfilepath[MAXPGPATH];
1808  File file;
1809 
1810  TempTablespacePath(tempdirpath, tblspcOid);
1811 
1812  /*
1813  * Generate a tempfile name that should be unique within the current
1814  * database instance.
1815  */
1816  snprintf(tempfilepath, sizeof(tempfilepath), "%s/%s%d.%ld",
1817  tempdirpath, PG_TEMP_FILE_PREFIX, MyProcPid, tempFileCounter++);
1818 
1819  /*
1820  * Open the file. Note: we don't use O_EXCL, in case there is an orphaned
1821  * temp file that can be reused.
1822  */
1823  file = PathNameOpenFile(tempfilepath,
1824  O_RDWR | O_CREAT | O_TRUNC | PG_BINARY);
1825  if (file <= 0)
1826  {
1827  /*
1828  * We might need to create the tablespace's tempfile directory, if no
1829  * one has yet done so.
1830  *
1831  * Don't check for an error from MakePGDirectory; it could fail if
1832  * someone else just did the same thing. If it doesn't work then
1833  * we'll bomb out on the second create attempt, instead.
1834  */
1835  (void) MakePGDirectory(tempdirpath);
1836 
1837  file = PathNameOpenFile(tempfilepath,
1838  O_RDWR | O_CREAT | O_TRUNC | PG_BINARY);
1839  if (file <= 0 && rejectError)
1840  elog(ERROR, "could not create temporary file \"%s\": %m",
1841  tempfilepath);
1842  }
1843 
1844  return file;
1845 }
1846 
1847 
1848 /*
1849  * Create a new file. The directory containing it must already exist. Files
1850  * created this way are subject to temp_file_limit and are automatically
1851  * closed at end of transaction, but are not automatically deleted on close
1852  * because they are intended to be shared between cooperating backends.
1853  *
1854  * If the file is inside the top-level temporary directory, its name should
1855  * begin with PG_TEMP_FILE_PREFIX so that it can be identified as temporary
1856  * and deleted at startup by RemovePgTempFiles(). Alternatively, it can be
1857  * inside a directory created with PathNameCreateTemporaryDir(), in which case
1858  * the prefix isn't needed.
1859  */
1860 File
1861 PathNameCreateTemporaryFile(const char *path, bool error_on_failure)
1862 {
1863  File file;
1864 
1865  Assert(temporary_files_allowed); /* check temp file access is up */
1866 
1868 
1869  /*
1870  * Open the file. Note: we don't use O_EXCL, in case there is an orphaned
1871  * temp file that can be reused.
1872  */
1873  file = PathNameOpenFile(path, O_RDWR | O_CREAT | O_TRUNC | PG_BINARY);
1874  if (file <= 0)
1875  {
1876  if (error_on_failure)
1877  ereport(ERROR,
1879  errmsg("could not create temporary file \"%s\": %m",
1880  path)));
1881  else
1882  return file;
1883  }
1884 
1885  /* Mark it for temp_file_limit accounting. */
1887 
1888  /* Register it for automatic close. */
1889  RegisterTemporaryFile(file);
1890 
1891  return file;
1892 }
1893 
1894 /*
1895  * Open a file that was created with PathNameCreateTemporaryFile, possibly in
1896  * another backend. Files opened this way don't count against the
1897  * temp_file_limit of the caller, are automatically closed at the end of the
1898  * transaction but are not deleted on close.
1899  */
1900 File
1901 PathNameOpenTemporaryFile(const char *path, int mode)
1902 {
1903  File file;
1904 
1905  Assert(temporary_files_allowed); /* check temp file access is up */
1906 
1908 
1909  file = PathNameOpenFile(path, mode | PG_BINARY);
1910 
1911  /* If no such file, then we don't raise an error. */
1912  if (file <= 0 && errno != ENOENT)
1913  ereport(ERROR,
1915  errmsg("could not open temporary file \"%s\": %m",
1916  path)));
1917 
1918  if (file > 0)
1919  {
1920  /* Register it for automatic close. */
1921  RegisterTemporaryFile(file);
1922  }
1923 
1924  return file;
1925 }
1926 
1927 /*
1928  * Delete a file by pathname. Return true if the file existed, false if
1929  * didn't.
1930  */
1931 bool
1932 PathNameDeleteTemporaryFile(const char *path, bool error_on_failure)
1933 {
1934  struct stat filestats;
1935  int stat_errno;
1936 
1937  /* Get the final size for pgstat reporting. */
1938  if (stat(path, &filestats) != 0)
1939  stat_errno = errno;
1940  else
1941  stat_errno = 0;
1942 
1943  /*
1944  * Unlike FileClose's automatic file deletion code, we tolerate
1945  * non-existence to support BufFileDeleteFileSet which doesn't know how
1946  * many segments it has to delete until it runs out.
1947  */
1948  if (stat_errno == ENOENT)
1949  return false;
1950 
1951  if (unlink(path) < 0)
1952  {
1953  if (errno != ENOENT)
1954  ereport(error_on_failure ? ERROR : LOG,
1956  errmsg("could not unlink temporary file \"%s\": %m",
1957  path)));
1958  return false;
1959  }
1960 
1961  if (stat_errno == 0)
1962  ReportTemporaryFileUsage(path, filestats.st_size);
1963  else
1964  {
1965  errno = stat_errno;
1966  ereport(LOG,
1968  errmsg("could not stat file \"%s\": %m", path)));
1969  }
1970 
1971  return true;
1972 }
1973 
1974 /*
1975  * close a file when done with it
1976  */
1977 void
1979 {
1980  Vfd *vfdP;
1981 
1982  Assert(FileIsValid(file));
1983 
1984  DO_DB(elog(LOG, "FileClose: %d (%s)",
1985  file, VfdCache[file].fileName));
1986 
1987  vfdP = &VfdCache[file];
1988 
1989  if (!FileIsNotOpen(file))
1990  {
1991  /* close the file */
1992  if (close(vfdP->fd) != 0)
1993  {
1994  /*
1995  * We may need to panic on failure to close non-temporary files;
1996  * see LruDelete.
1997  */
1999  "could not close file \"%s\": %m", vfdP->fileName);
2000  }
2001 
2002  --nfile;
2003  vfdP->fd = VFD_CLOSED;
2004 
2005  /* remove the file from the lru ring */
2006  Delete(file);
2007  }
2008 
2009  if (vfdP->fdstate & FD_TEMP_FILE_LIMIT)
2010  {
2011  /* Subtract its size from current usage (do first in case of error) */
2012  temporary_files_size -= vfdP->fileSize;
2013  vfdP->fileSize = 0;
2014  }
2015 
2016  /*
2017  * Delete the file if it was temporary, and make a log entry if wanted
2018  */
2019  if (vfdP->fdstate & FD_DELETE_AT_CLOSE)
2020  {
2021  struct stat filestats;
2022  int stat_errno;
2023 
2024  /*
2025  * If we get an error, as could happen within the ereport/elog calls,
2026  * we'll come right back here during transaction abort. Reset the
2027  * flag to ensure that we can't get into an infinite loop. This code
2028  * is arranged to ensure that the worst-case consequence is failing to
2029  * emit log message(s), not failing to attempt the unlink.
2030  */
2031  vfdP->fdstate &= ~FD_DELETE_AT_CLOSE;
2032 
2033 
2034  /* first try the stat() */
2035  if (stat(vfdP->fileName, &filestats))
2036  stat_errno = errno;
2037  else
2038  stat_errno = 0;
2039 
2040  /* in any case do the unlink */
2041  if (unlink(vfdP->fileName))
2042  ereport(LOG,
2044  errmsg("could not delete file \"%s\": %m", vfdP->fileName)));
2045 
2046  /* and last report the stat results */
2047  if (stat_errno == 0)
2048  ReportTemporaryFileUsage(vfdP->fileName, filestats.st_size);
2049  else
2050  {
2051  errno = stat_errno;
2052  ereport(LOG,
2054  errmsg("could not stat file \"%s\": %m", vfdP->fileName)));
2055  }
2056  }
2057 
2058  /* Unregister it from the resource owner */
2059  if (vfdP->resowner)
2060  ResourceOwnerForgetFile(vfdP->resowner, file);
2061 
2062  /*
2063  * Return the Vfd slot to the free list
2064  */
2065  FreeVfd(file);
2066 }
2067 
2068 /*
2069  * FilePrefetch - initiate asynchronous read of a given range of the file.
2070  *
2071  * Currently the only implementation of this function is using posix_fadvise
2072  * which is the simplest standardized interface that accomplishes this.
2073  * We could add an implementation using libaio in the future; but note that
2074  * this API is inappropriate for libaio, which wants to have a buffer provided
2075  * to read into.
2076  */
2077 int
2078 FilePrefetch(File file, off_t offset, off_t amount, uint32 wait_event_info)
2079 {
2080 #if defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_WILLNEED)
2081  int returnCode;
2082 
2083  Assert(FileIsValid(file));
2084 
2085  DO_DB(elog(LOG, "FilePrefetch: %d (%s) " INT64_FORMAT " " INT64_FORMAT,
2086  file, VfdCache[file].fileName,
2087  (int64) offset, (int64) amount));
2088 
2089  returnCode = FileAccess(file);
2090  if (returnCode < 0)
2091  return returnCode;
2092 
2093 retry:
2094  pgstat_report_wait_start(wait_event_info);
2095  returnCode = posix_fadvise(VfdCache[file].fd, offset, amount,
2096  POSIX_FADV_WILLNEED);
2098 
2099  if (returnCode == EINTR)
2100  goto retry;
2101 
2102  return returnCode;
2103 #else
2104  Assert(FileIsValid(file));
2105  return 0;
2106 #endif
2107 }
2108 
2109 void
2110 FileWriteback(File file, off_t offset, off_t nbytes, uint32 wait_event_info)
2111 {
2112  int returnCode;
2113 
2114  Assert(FileIsValid(file));
2115 
2116  DO_DB(elog(LOG, "FileWriteback: %d (%s) " INT64_FORMAT " " INT64_FORMAT,
2117  file, VfdCache[file].fileName,
2118  (int64) offset, (int64) nbytes));
2119 
2120  if (nbytes <= 0)
2121  return;
2122 
2123  if (VfdCache[file].fileFlags & PG_O_DIRECT)
2124  return;
2125 
2126  returnCode = FileAccess(file);
2127  if (returnCode < 0)
2128  return;
2129 
2130  pgstat_report_wait_start(wait_event_info);
2131  pg_flush_data(VfdCache[file].fd, offset, nbytes);
2133 }
2134 
2135 ssize_t
2136 FileReadV(File file, const struct iovec *iov, int iovcnt, off_t offset,
2137  uint32 wait_event_info)
2138 {
2139  ssize_t returnCode;
2140  Vfd *vfdP;
2141 
2142  Assert(FileIsValid(file));
2143 
2144  DO_DB(elog(LOG, "FileReadV: %d (%s) " INT64_FORMAT " %d",
2145  file, VfdCache[file].fileName,
2146  (int64) offset,
2147  iovcnt));
2148 
2149  returnCode = FileAccess(file);
2150  if (returnCode < 0)
2151  return returnCode;
2152 
2153  vfdP = &VfdCache[file];
2154 
2155 retry:
2156  pgstat_report_wait_start(wait_event_info);
2157  returnCode = pg_preadv(vfdP->fd, iov, iovcnt, offset);
2159 
2160  if (returnCode < 0)
2161  {
2162  /*
2163  * Windows may run out of kernel buffers and return "Insufficient
2164  * system resources" error. Wait a bit and retry to solve it.
2165  *
2166  * It is rumored that EINTR is also possible on some Unix filesystems,
2167  * in which case immediate retry is indicated.
2168  */
2169 #ifdef WIN32
2170  DWORD error = GetLastError();
2171 
2172  switch (error)
2173  {
2174  case ERROR_NO_SYSTEM_RESOURCES:
2175  pg_usleep(1000L);
2176  errno = EINTR;
2177  break;
2178  default:
2179  _dosmaperr(error);
2180  break;
2181  }
2182 #endif
2183  /* OK to retry if interrupted */
2184  if (errno == EINTR)
2185  goto retry;
2186  }
2187 
2188  return returnCode;
2189 }
2190 
2191 ssize_t
2192 FileWriteV(File file, const struct iovec *iov, int iovcnt, off_t offset,
2193  uint32 wait_event_info)
2194 {
2195  ssize_t returnCode;
2196  Vfd *vfdP;
2197 
2198  Assert(FileIsValid(file));
2199 
2200  DO_DB(elog(LOG, "FileWriteV: %d (%s) " INT64_FORMAT " %d",
2201  file, VfdCache[file].fileName,
2202  (int64) offset,
2203  iovcnt));
2204 
2205  returnCode = FileAccess(file);
2206  if (returnCode < 0)
2207  return returnCode;
2208 
2209  vfdP = &VfdCache[file];
2210 
2211  /*
2212  * If enforcing temp_file_limit and it's a temp file, check to see if the
2213  * write would overrun temp_file_limit, and throw error if so. Note: it's
2214  * really a modularity violation to throw error here; we should set errno
2215  * and return -1. However, there's no way to report a suitable error
2216  * message if we do that. All current callers would just throw error
2217  * immediately anyway, so this is safe at present.
2218  */
2219  if (temp_file_limit >= 0 && (vfdP->fdstate & FD_TEMP_FILE_LIMIT))
2220  {
2221  off_t past_write = offset;
2222 
2223  for (int i = 0; i < iovcnt; ++i)
2224  past_write += iov[i].iov_len;
2225 
2226  if (past_write > vfdP->fileSize)
2227  {
2228  uint64 newTotal = temporary_files_size;
2229 
2230  newTotal += past_write - vfdP->fileSize;
2231  if (newTotal > (uint64) temp_file_limit * (uint64) 1024)
2232  ereport(ERROR,
2233  (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED),
2234  errmsg("temporary file size exceeds temp_file_limit (%dkB)",
2235  temp_file_limit)));
2236  }
2237  }
2238 
2239 retry:
2240  pgstat_report_wait_start(wait_event_info);
2241  returnCode = pg_pwritev(vfdP->fd, iov, iovcnt, offset);
2243 
2244  if (returnCode >= 0)
2245  {
2246  /*
2247  * Some callers expect short writes to set errno, and traditionally we
2248  * have assumed that they imply disk space shortage. We don't want to
2249  * waste CPU cycles adding up the total size here, so we'll just set
2250  * it for all successful writes in case such a caller determines that
2251  * the write was short and ereports "%m".
2252  */
2253  errno = ENOSPC;
2254 
2255  /*
2256  * Maintain fileSize and temporary_files_size if it's a temp file.
2257  */
2258  if (vfdP->fdstate & FD_TEMP_FILE_LIMIT)
2259  {
2260  off_t past_write = offset + returnCode;
2261 
2262  if (past_write > vfdP->fileSize)
2263  {
2264  temporary_files_size += past_write - vfdP->fileSize;
2265  vfdP->fileSize = past_write;
2266  }
2267  }
2268  }
2269  else
2270  {
2271  /*
2272  * See comments in FileReadV()
2273  */
2274 #ifdef WIN32
2275  DWORD error = GetLastError();
2276 
2277  switch (error)
2278  {
2279  case ERROR_NO_SYSTEM_RESOURCES:
2280  pg_usleep(1000L);
2281  errno = EINTR;
2282  break;
2283  default:
2284  _dosmaperr(error);
2285  break;
2286  }
2287 #endif
2288  /* OK to retry if interrupted */
2289  if (errno == EINTR)
2290  goto retry;
2291  }
2292 
2293  return returnCode;
2294 }
2295 
2296 int
2297 FileSync(File file, uint32 wait_event_info)
2298 {
2299  int returnCode;
2300 
2301  Assert(FileIsValid(file));
2302 
2303  DO_DB(elog(LOG, "FileSync: %d (%s)",
2304  file, VfdCache[file].fileName));
2305 
2306  returnCode = FileAccess(file);
2307  if (returnCode < 0)
2308  return returnCode;
2309 
2310  pgstat_report_wait_start(wait_event_info);
2311  returnCode = pg_fsync(VfdCache[file].fd);
2313 
2314  return returnCode;
2315 }
2316 
2317 /*
2318  * Zero a region of the file.
2319  *
2320  * Returns 0 on success, -1 otherwise. In the latter case errno is set to the
2321  * appropriate error.
2322  */
2323 int
2324 FileZero(File file, off_t offset, off_t amount, uint32 wait_event_info)
2325 {
2326  int returnCode;
2327  ssize_t written;
2328 
2329  Assert(FileIsValid(file));
2330 
2331  DO_DB(elog(LOG, "FileZero: %d (%s) " INT64_FORMAT " " INT64_FORMAT,
2332  file, VfdCache[file].fileName,
2333  (int64) offset, (int64) amount));
2334 
2335  returnCode = FileAccess(file);
2336  if (returnCode < 0)
2337  return returnCode;
2338 
2339  pgstat_report_wait_start(wait_event_info);
2340  written = pg_pwrite_zeros(VfdCache[file].fd, amount, offset);
2342 
2343  if (written < 0)
2344  return -1;
2345  else if (written != amount)
2346  {
2347  /* if errno is unset, assume problem is no disk space */
2348  if (errno == 0)
2349  errno = ENOSPC;
2350  return -1;
2351  }
2352 
2353  return 0;
2354 }
2355 
2356 /*
2357  * Try to reserve file space with posix_fallocate(). If posix_fallocate() is
2358  * not implemented on the operating system or fails with EINVAL / EOPNOTSUPP,
2359  * use FileZero() instead.
2360  *
2361  * Note that at least glibc() implements posix_fallocate() in userspace if not
2362  * implemented by the filesystem. That's not the case for all environments
2363  * though.
2364  *
2365  * Returns 0 on success, -1 otherwise. In the latter case errno is set to the
2366  * appropriate error.
2367  */
2368 int
2369 FileFallocate(File file, off_t offset, off_t amount, uint32 wait_event_info)
2370 {
2371 #ifdef HAVE_POSIX_FALLOCATE
2372  int returnCode;
2373 
2374  Assert(FileIsValid(file));
2375 
2376  DO_DB(elog(LOG, "FileFallocate: %d (%s) " INT64_FORMAT " " INT64_FORMAT,
2377  file, VfdCache[file].fileName,
2378  (int64) offset, (int64) amount));
2379 
2380  returnCode = FileAccess(file);
2381  if (returnCode < 0)
2382  return -1;
2383 
2384 retry:
2385  pgstat_report_wait_start(wait_event_info);
2386  returnCode = posix_fallocate(VfdCache[file].fd, offset, amount);
2388 
2389  if (returnCode == 0)
2390  return 0;
2391  else if (returnCode == EINTR)
2392  goto retry;
2393 
2394  /* for compatibility with %m printing etc */
2395  errno = returnCode;
2396 
2397  /*
2398  * Return in cases of a "real" failure, if fallocate is not supported,
2399  * fall through to the FileZero() backed implementation.
2400  */
2401  if (returnCode != EINVAL && returnCode != EOPNOTSUPP)
2402  return -1;
2403 #endif
2404 
2405  return FileZero(file, offset, amount, wait_event_info);
2406 }
2407 
2408 off_t
2410 {
2411  Assert(FileIsValid(file));
2412 
2413  DO_DB(elog(LOG, "FileSize %d (%s)",
2414  file, VfdCache[file].fileName));
2415 
2416  if (FileIsNotOpen(file))
2417  {
2418  if (FileAccess(file) < 0)
2419  return (off_t) -1;
2420  }
2421 
2422  return lseek(VfdCache[file].fd, 0, SEEK_END);
2423 }
2424 
2425 int
2426 FileTruncate(File file, off_t offset, uint32 wait_event_info)
2427 {
2428  int returnCode;
2429 
2430  Assert(FileIsValid(file));
2431 
2432  DO_DB(elog(LOG, "FileTruncate %d (%s)",
2433  file, VfdCache[file].fileName));
2434 
2435  returnCode = FileAccess(file);
2436  if (returnCode < 0)
2437  return returnCode;
2438 
2439  pgstat_report_wait_start(wait_event_info);
2440  returnCode = pg_ftruncate(VfdCache[file].fd, offset);
2442 
2443  if (returnCode == 0 && VfdCache[file].fileSize > offset)
2444  {
2445  /* adjust our state for truncation of a temp file */
2446  Assert(VfdCache[file].fdstate & FD_TEMP_FILE_LIMIT);
2447  temporary_files_size -= VfdCache[file].fileSize - offset;
2448  VfdCache[file].fileSize = offset;
2449  }
2450 
2451  return returnCode;
2452 }
2453 
2454 /*
2455  * Return the pathname associated with an open file.
2456  *
2457  * The returned string points to an internal buffer, which is valid until
2458  * the file is closed.
2459  */
2460 char *
2462 {
2463  Assert(FileIsValid(file));
2464 
2465  return VfdCache[file].fileName;
2466 }
2467 
2468 /*
2469  * Return the raw file descriptor of an opened file.
2470  *
2471  * The returned file descriptor will be valid until the file is closed, but
2472  * there are a lot of things that can make that happen. So the caller should
2473  * be careful not to do much of anything else before it finishes using the
2474  * returned file descriptor.
2475  */
2476 int
2478 {
2479  Assert(FileIsValid(file));
2480  return VfdCache[file].fd;
2481 }
2482 
2483 /*
2484  * FileGetRawFlags - returns the file flags on open(2)
2485  */
2486 int
2488 {
2489  Assert(FileIsValid(file));
2490  return VfdCache[file].fileFlags;
2491 }
2492 
2493 /*
2494  * FileGetRawMode - returns the mode bitmask passed to open(2)
2495  */
2496 mode_t
2498 {
2499  Assert(FileIsValid(file));
2500  return VfdCache[file].fileMode;
2501 }
2502 
2503 /*
2504  * Make room for another allocatedDescs[] array entry if needed and possible.
2505  * Returns true if an array element is available.
2506  */
2507 static bool
2509 {
2510  AllocateDesc *newDescs;
2511  int newMax;
2512 
2513  /* Quick out if array already has a free slot. */
2515  return true;
2516 
2517  /*
2518  * If the array hasn't yet been created in the current process, initialize
2519  * it with FD_MINFREE / 3 elements. In many scenarios this is as many as
2520  * we will ever need, anyway. We don't want to look at max_safe_fds
2521  * immediately because set_max_safe_fds() may not have run yet.
2522  */
2523  if (allocatedDescs == NULL)
2524  {
2525  newMax = FD_MINFREE / 3;
2526  newDescs = (AllocateDesc *) malloc(newMax * sizeof(AllocateDesc));
2527  /* Out of memory already? Treat as fatal error. */
2528  if (newDescs == NULL)
2529  ereport(ERROR,
2530  (errcode(ERRCODE_OUT_OF_MEMORY),
2531  errmsg("out of memory")));
2532  allocatedDescs = newDescs;
2533  maxAllocatedDescs = newMax;
2534  return true;
2535  }
2536 
2537  /*
2538  * Consider enlarging the array beyond the initial allocation used above.
2539  * By the time this happens, max_safe_fds should be known accurately.
2540  *
2541  * We mustn't let allocated descriptors hog all the available FDs, and in
2542  * practice we'd better leave a reasonable number of FDs for VFD use. So
2543  * set the maximum to max_safe_fds / 3. (This should certainly be at
2544  * least as large as the initial size, FD_MINFREE / 3, so we aren't
2545  * tightening the restriction here.) Recall that "external" FDs are
2546  * allowed to consume another third of max_safe_fds.
2547  */
2548  newMax = max_safe_fds / 3;
2549  if (newMax > maxAllocatedDescs)
2550  {
2551  newDescs = (AllocateDesc *) realloc(allocatedDescs,
2552  newMax * sizeof(AllocateDesc));
2553  /* Treat out-of-memory as a non-fatal error. */
2554  if (newDescs == NULL)
2555  return false;
2556  allocatedDescs = newDescs;
2557  maxAllocatedDescs = newMax;
2558  return true;
2559  }
2560 
2561  /* Can't enlarge allocatedDescs[] any more. */
2562  return false;
2563 }
2564 
2565 /*
2566  * Routines that want to use stdio (ie, FILE*) should use AllocateFile
2567  * rather than plain fopen(). This lets fd.c deal with freeing FDs if
2568  * necessary to open the file. When done, call FreeFile rather than fclose.
2569  *
2570  * Note that files that will be open for any significant length of time
2571  * should NOT be handled this way, since they cannot share kernel file
2572  * descriptors with other files; there is grave risk of running out of FDs
2573  * if anyone locks down too many FDs. Most callers of this routine are
2574  * simply reading a config file that they will read and close immediately.
2575  *
2576  * fd.c will automatically close all files opened with AllocateFile at
2577  * transaction commit or abort; this prevents FD leakage if a routine
2578  * that calls AllocateFile is terminated prematurely by ereport(ERROR).
2579  *
2580  * Ideally this should be the *only* direct call of fopen() in the backend.
2581  */
2582 FILE *
2583 AllocateFile(const char *name, const char *mode)
2584 {
2585  FILE *file;
2586 
2587  DO_DB(elog(LOG, "AllocateFile: Allocated %d (%s)",
2589 
2590  /* Can we allocate another non-virtual FD? */
2591  if (!reserveAllocatedDesc())
2592  ereport(ERROR,
2593  (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
2594  errmsg("exceeded maxAllocatedDescs (%d) while trying to open file \"%s\"",
2595  maxAllocatedDescs, name)));
2596 
2597  /* Close excess kernel FDs. */
2598  ReleaseLruFiles();
2599 
2600 TryAgain:
2601  if ((file = fopen(name, mode)) != NULL)
2602  {
2604 
2605  desc->kind = AllocateDescFile;
2606  desc->desc.file = file;
2609  return desc->desc.file;
2610  }
2611 
2612  if (errno == EMFILE || errno == ENFILE)
2613  {
2614  int save_errno = errno;
2615 
2616  ereport(LOG,
2617  (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
2618  errmsg("out of file descriptors: %m; release and retry")));
2619  errno = 0;
2620  if (ReleaseLruFile())
2621  goto TryAgain;
2622  errno = save_errno;
2623  }
2624 
2625  return NULL;
2626 }
2627 
2628 /*
2629  * Open a file with OpenTransientFilePerm() and pass default file mode for
2630  * the fileMode parameter.
2631  */
2632 int
2633 OpenTransientFile(const char *fileName, int fileFlags)
2634 {
2635  return OpenTransientFilePerm(fileName, fileFlags, pg_file_create_mode);
2636 }
2637 
2638 /*
2639  * Like AllocateFile, but returns an unbuffered fd like open(2)
2640  */
2641 int
2642 OpenTransientFilePerm(const char *fileName, int fileFlags, mode_t fileMode)
2643 {
2644  int fd;
2645 
2646  DO_DB(elog(LOG, "OpenTransientFile: Allocated %d (%s)",
2647  numAllocatedDescs, fileName));
2648 
2649  /* Can we allocate another non-virtual FD? */
2650  if (!reserveAllocatedDesc())
2651  ereport(ERROR,
2652  (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
2653  errmsg("exceeded maxAllocatedDescs (%d) while trying to open file \"%s\"",
2654  maxAllocatedDescs, fileName)));
2655 
2656  /* Close excess kernel FDs. */
2657  ReleaseLruFiles();
2658 
2659  fd = BasicOpenFilePerm(fileName, fileFlags, fileMode);
2660 
2661  if (fd >= 0)
2662  {
2664 
2665  desc->kind = AllocateDescRawFD;
2666  desc->desc.fd = fd;
2669 
2670  return fd;
2671  }
2672 
2673  return -1; /* failure */
2674 }
2675 
2676 /*
2677  * Routines that want to initiate a pipe stream should use OpenPipeStream
2678  * rather than plain popen(). This lets fd.c deal with freeing FDs if
2679  * necessary. When done, call ClosePipeStream rather than pclose.
2680  *
2681  * This function also ensures that the popen'd program is run with default
2682  * SIGPIPE processing, rather than the SIG_IGN setting the backend normally
2683  * uses. This ensures desirable response to, eg, closing a read pipe early.
2684  */
2685 FILE *
2686 OpenPipeStream(const char *command, const char *mode)
2687 {
2688  FILE *file;
2689  int save_errno;
2690 
2691  DO_DB(elog(LOG, "OpenPipeStream: Allocated %d (%s)",
2692  numAllocatedDescs, command));
2693 
2694  /* Can we allocate another non-virtual FD? */
2695  if (!reserveAllocatedDesc())
2696  ereport(ERROR,
2697  (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
2698  errmsg("exceeded maxAllocatedDescs (%d) while trying to execute command \"%s\"",
2699  maxAllocatedDescs, command)));
2700 
2701  /* Close excess kernel FDs. */
2702  ReleaseLruFiles();
2703 
2704 TryAgain:
2705  fflush(NULL);
2707  errno = 0;
2708  file = popen(command, mode);
2709  save_errno = errno;
2711  errno = save_errno;
2712  if (file != NULL)
2713  {
2715 
2716  desc->kind = AllocateDescPipe;
2717  desc->desc.file = file;
2720  return desc->desc.file;
2721  }
2722 
2723  if (errno == EMFILE || errno == ENFILE)
2724  {
2725  ereport(LOG,
2726  (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
2727  errmsg("out of file descriptors: %m; release and retry")));
2728  if (ReleaseLruFile())
2729  goto TryAgain;
2730  errno = save_errno;
2731  }
2732 
2733  return NULL;
2734 }
2735 
2736 /*
2737  * Free an AllocateDesc of any type.
2738  *
2739  * The argument *must* point into the allocatedDescs[] array.
2740  */
2741 static int
2743 {
2744  int result;
2745 
2746  /* Close the underlying object */
2747  switch (desc->kind)
2748  {
2749  case AllocateDescFile:
2750  result = fclose(desc->desc.file);
2751  break;
2752  case AllocateDescPipe:
2753  result = pclose(desc->desc.file);
2754  break;
2755  case AllocateDescDir:
2756  result = closedir(desc->desc.dir);
2757  break;
2758  case AllocateDescRawFD:
2759  result = close(desc->desc.fd);
2760  break;
2761  default:
2762  elog(ERROR, "AllocateDesc kind not recognized");
2763  result = 0; /* keep compiler quiet */
2764  break;
2765  }
2766 
2767  /* Compact storage in the allocatedDescs array */
2770 
2771  return result;
2772 }
2773 
2774 /*
2775  * Close a file returned by AllocateFile.
2776  *
2777  * Note we do not check fclose's return value --- it is up to the caller
2778  * to handle close errors.
2779  */
2780 int
2781 FreeFile(FILE *file)
2782 {
2783  int i;
2784 
2785  DO_DB(elog(LOG, "FreeFile: Allocated %d", numAllocatedDescs));
2786 
2787  /* Remove file from list of allocated files, if it's present */
2788  for (i = numAllocatedDescs; --i >= 0;)
2789  {
2790  AllocateDesc *desc = &allocatedDescs[i];
2791 
2792  if (desc->kind == AllocateDescFile && desc->desc.file == file)
2793  return FreeDesc(desc);
2794  }
2795 
2796  /* Only get here if someone passes us a file not in allocatedDescs */
2797  elog(WARNING, "file passed to FreeFile was not obtained from AllocateFile");
2798 
2799  return fclose(file);
2800 }
2801 
2802 /*
2803  * Close a file returned by OpenTransientFile.
2804  *
2805  * Note we do not check close's return value --- it is up to the caller
2806  * to handle close errors.
2807  */
2808 int
2810 {
2811  int i;
2812 
2813  DO_DB(elog(LOG, "CloseTransientFile: Allocated %d", numAllocatedDescs));
2814 
2815  /* Remove fd from list of allocated files, if it's present */
2816  for (i = numAllocatedDescs; --i >= 0;)
2817  {
2818  AllocateDesc *desc = &allocatedDescs[i];
2819 
2820  if (desc->kind == AllocateDescRawFD && desc->desc.fd == fd)
2821  return FreeDesc(desc);
2822  }
2823 
2824  /* Only get here if someone passes us a file not in allocatedDescs */
2825  elog(WARNING, "fd passed to CloseTransientFile was not obtained from OpenTransientFile");
2826 
2827  return close(fd);
2828 }
2829 
2830 /*
2831  * Routines that want to use <dirent.h> (ie, DIR*) should use AllocateDir
2832  * rather than plain opendir(). This lets fd.c deal with freeing FDs if
2833  * necessary to open the directory, and with closing it after an elog.
2834  * When done, call FreeDir rather than closedir.
2835  *
2836  * Returns NULL, with errno set, on failure. Note that failure detection
2837  * is commonly left to the following call of ReadDir or ReadDirExtended;
2838  * see the comments for ReadDir.
2839  *
2840  * Ideally this should be the *only* direct call of opendir() in the backend.
2841  */
2842 DIR *
2843 AllocateDir(const char *dirname)
2844 {
2845  DIR *dir;
2846 
2847  DO_DB(elog(LOG, "AllocateDir: Allocated %d (%s)",
2848  numAllocatedDescs, dirname));
2849 
2850  /* Can we allocate another non-virtual FD? */
2851  if (!reserveAllocatedDesc())
2852  ereport(ERROR,
2853  (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
2854  errmsg("exceeded maxAllocatedDescs (%d) while trying to open directory \"%s\"",
2855  maxAllocatedDescs, dirname)));
2856 
2857  /* Close excess kernel FDs. */
2858  ReleaseLruFiles();
2859 
2860 TryAgain:
2861  if ((dir = opendir(dirname)) != NULL)
2862  {
2864 
2865  desc->kind = AllocateDescDir;
2866  desc->desc.dir = dir;
2869  return desc->desc.dir;
2870  }
2871 
2872  if (errno == EMFILE || errno == ENFILE)
2873  {
2874  int save_errno = errno;
2875 
2876  ereport(LOG,
2877  (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
2878  errmsg("out of file descriptors: %m; release and retry")));
2879  errno = 0;
2880  if (ReleaseLruFile())
2881  goto TryAgain;
2882  errno = save_errno;
2883  }
2884 
2885  return NULL;
2886 }
2887 
2888 /*
2889  * Read a directory opened with AllocateDir, ereport'ing any error.
2890  *
2891  * This is easier to use than raw readdir() since it takes care of some
2892  * otherwise rather tedious and error-prone manipulation of errno. Also,
2893  * if you are happy with a generic error message for AllocateDir failure,
2894  * you can just do
2895  *
2896  * dir = AllocateDir(path);
2897  * while ((dirent = ReadDir(dir, path)) != NULL)
2898  * process dirent;
2899  * FreeDir(dir);
2900  *
2901  * since a NULL dir parameter is taken as indicating AllocateDir failed.
2902  * (Make sure errno isn't changed between AllocateDir and ReadDir if you
2903  * use this shortcut.)
2904  *
2905  * The pathname passed to AllocateDir must be passed to this routine too,
2906  * but it is only used for error reporting.
2907  */
2908 struct dirent *
2909 ReadDir(DIR *dir, const char *dirname)
2910 {
2911  return ReadDirExtended(dir, dirname, ERROR);
2912 }
2913 
2914 /*
2915  * Alternate version of ReadDir that allows caller to specify the elevel
2916  * for any error report (whether it's reporting an initial failure of
2917  * AllocateDir or a subsequent directory read failure).
2918  *
2919  * If elevel < ERROR, returns NULL after any error. With the normal coding
2920  * pattern, this will result in falling out of the loop immediately as
2921  * though the directory contained no (more) entries.
2922  */
2923 struct dirent *
2924 ReadDirExtended(DIR *dir, const char *dirname, int elevel)
2925 {
2926  struct dirent *dent;
2927 
2928  /* Give a generic message for AllocateDir failure, if caller didn't */
2929  if (dir == NULL)
2930  {
2931  ereport(elevel,
2933  errmsg("could not open directory \"%s\": %m",
2934  dirname)));
2935  return NULL;
2936  }
2937 
2938  errno = 0;
2939  if ((dent = readdir(dir)) != NULL)
2940  return dent;
2941 
2942  if (errno)
2943  ereport(elevel,
2945  errmsg("could not read directory \"%s\": %m",
2946  dirname)));
2947  return NULL;
2948 }
2949 
2950 /*
2951  * Close a directory opened with AllocateDir.
2952  *
2953  * Returns closedir's return value (with errno set if it's not 0).
2954  * Note we do not check the return value --- it is up to the caller
2955  * to handle close errors if wanted.
2956  *
2957  * Does nothing if dir == NULL; we assume that directory open failure was
2958  * already reported if desired.
2959  */
2960 int
2962 {
2963  int i;
2964 
2965  /* Nothing to do if AllocateDir failed */
2966  if (dir == NULL)
2967  return 0;
2968 
2969  DO_DB(elog(LOG, "FreeDir: Allocated %d", numAllocatedDescs));
2970 
2971  /* Remove dir from list of allocated dirs, if it's present */
2972  for (i = numAllocatedDescs; --i >= 0;)
2973  {
2974  AllocateDesc *desc = &allocatedDescs[i];
2975 
2976  if (desc->kind == AllocateDescDir && desc->desc.dir == dir)
2977  return FreeDesc(desc);
2978  }
2979 
2980  /* Only get here if someone passes us a dir not in allocatedDescs */
2981  elog(WARNING, "dir passed to FreeDir was not obtained from AllocateDir");
2982 
2983  return closedir(dir);
2984 }
2985 
2986 
2987 /*
2988  * Close a pipe stream returned by OpenPipeStream.
2989  */
2990 int
2991 ClosePipeStream(FILE *file)
2992 {
2993  int i;
2994 
2995  DO_DB(elog(LOG, "ClosePipeStream: Allocated %d", numAllocatedDescs));
2996 
2997  /* Remove file from list of allocated files, if it's present */
2998  for (i = numAllocatedDescs; --i >= 0;)
2999  {
3000  AllocateDesc *desc = &allocatedDescs[i];
3001 
3002  if (desc->kind == AllocateDescPipe && desc->desc.file == file)
3003  return FreeDesc(desc);
3004  }
3005 
3006  /* Only get here if someone passes us a file not in allocatedDescs */
3007  elog(WARNING, "file passed to ClosePipeStream was not obtained from OpenPipeStream");
3008 
3009  return pclose(file);
3010 }
3011 
3012 /*
3013  * closeAllVfds
3014  *
3015  * Force all VFDs into the physically-closed state, so that the fewest
3016  * possible number of kernel file descriptors are in use. There is no
3017  * change in the logical state of the VFDs.
3018  */
3019 void
3021 {
3022  Index i;
3023 
3024  if (SizeVfdCache > 0)
3025  {
3026  Assert(FileIsNotOpen(0)); /* Make sure ring not corrupted */
3027  for (i = 1; i < SizeVfdCache; i++)
3028  {
3029  if (!FileIsNotOpen(i))
3030  LruDelete(i);
3031  }
3032  }
3033 }
3034 
3035 
3036 /*
3037  * SetTempTablespaces
3038  *
3039  * Define a list (actually an array) of OIDs of tablespaces to use for
3040  * temporary files. This list will be used until end of transaction,
3041  * unless this function is called again before then. It is caller's
3042  * responsibility that the passed-in array has adequate lifespan (typically
3043  * it'd be allocated in TopTransactionContext).
3044  *
3045  * Some entries of the array may be InvalidOid, indicating that the current
3046  * database's default tablespace should be used.
3047  */
3048 void
3049 SetTempTablespaces(Oid *tableSpaces, int numSpaces)
3050 {
3051  Assert(numSpaces >= 0);
3052  tempTableSpaces = tableSpaces;
3053  numTempTableSpaces = numSpaces;
3054 
3055  /*
3056  * Select a random starting point in the list. This is to minimize
3057  * conflicts between backends that are most likely sharing the same list
3058  * of temp tablespaces. Note that if we create multiple temp files in the
3059  * same transaction, we'll advance circularly through the list --- this
3060  * ensures that large temporary sort files are nicely spread across all
3061  * available tablespaces.
3062  */
3063  if (numSpaces > 1)
3065  0, numSpaces - 1);
3066  else
3067  nextTempTableSpace = 0;
3068 }
3069 
3070 /*
3071  * TempTablespacesAreSet
3072  *
3073  * Returns true if SetTempTablespaces has been called in current transaction.
3074  * (This is just so that tablespaces.c doesn't need its own per-transaction
3075  * state.)
3076  */
3077 bool
3079 {
3080  return (numTempTableSpaces >= 0);
3081 }
3082 
3083 /*
3084  * GetTempTablespaces
3085  *
3086  * Populate an array with the OIDs of the tablespaces that should be used for
3087  * temporary files. (Some entries may be InvalidOid, indicating that the
3088  * current database's default tablespace should be used.) At most numSpaces
3089  * entries will be filled.
3090  * Returns the number of OIDs that were copied into the output array.
3091  */
3092 int
3093 GetTempTablespaces(Oid *tableSpaces, int numSpaces)
3094 {
3095  int i;
3096 
3098  for (i = 0; i < numTempTableSpaces && i < numSpaces; ++i)
3099  tableSpaces[i] = tempTableSpaces[i];
3100 
3101  return i;
3102 }
3103 
3104 /*
3105  * GetNextTempTableSpace
3106  *
3107  * Select the next temp tablespace to use. A result of InvalidOid means
3108  * to use the current database's default tablespace.
3109  */
3110 Oid
3112 {
3113  if (numTempTableSpaces > 0)
3114  {
3115  /* Advance nextTempTableSpace counter with wraparound */
3117  nextTempTableSpace = 0;
3119  }
3120  return InvalidOid;
3121 }
3122 
3123 
3124 /*
3125  * AtEOSubXact_Files
3126  *
3127  * Take care of subtransaction commit/abort. At abort, we close temp files
3128  * that the subtransaction may have opened. At commit, we reassign the
3129  * files that were opened to the parent subtransaction.
3130  */
3131 void
3132 AtEOSubXact_Files(bool isCommit, SubTransactionId mySubid,
3133  SubTransactionId parentSubid)
3134 {
3135  Index i;
3136 
3137  for (i = 0; i < numAllocatedDescs; i++)
3138  {
3139  if (allocatedDescs[i].create_subid == mySubid)
3140  {
3141  if (isCommit)
3142  allocatedDescs[i].create_subid = parentSubid;
3143  else
3144  {
3145  /* have to recheck the item after FreeDesc (ugly) */
3146  FreeDesc(&allocatedDescs[i--]);
3147  }
3148  }
3149  }
3150 }
3151 
3152 /*
3153  * AtEOXact_Files
3154  *
3155  * This routine is called during transaction commit or abort. All still-open
3156  * per-transaction temporary file VFDs are closed, which also causes the
3157  * underlying files to be deleted (although they should've been closed already
3158  * by the ResourceOwner cleanup). Furthermore, all "allocated" stdio files are
3159  * closed. We also forget any transaction-local temp tablespace list.
3160  *
3161  * The isCommit flag is used only to decide whether to emit warnings about
3162  * unclosed files.
3163  */
3164 void
3165 AtEOXact_Files(bool isCommit)
3166 {
3167  CleanupTempFiles(isCommit, false);
3168  tempTableSpaces = NULL;
3169  numTempTableSpaces = -1;
3170 }
3171 
3172 /*
3173  * BeforeShmemExit_Files
3174  *
3175  * before_shmem_exit hook to clean up temp files during backend shutdown.
3176  * Here, we want to clean up *all* temp files including interXact ones.
3177  */
3178 static void
3180 {
3181  CleanupTempFiles(false, true);
3182 
3183  /* prevent further temp files from being created */
3184 #ifdef USE_ASSERT_CHECKING
3185  temporary_files_allowed = false;
3186 #endif
3187 }
3188 
3189 /*
3190  * Close temporary files and delete their underlying files.
3191  *
3192  * isCommit: if true, this is normal transaction commit, and we don't
3193  * expect any remaining files; warn if there are some.
3194  *
3195  * isProcExit: if true, this is being called as the backend process is
3196  * exiting. If that's the case, we should remove all temporary files; if
3197  * that's not the case, we are being called for transaction commit/abort
3198  * and should only remove transaction-local temp files. In either case,
3199  * also clean up "allocated" stdio files, dirs and fds.
3200  */
3201 static void
3202 CleanupTempFiles(bool isCommit, bool isProcExit)
3203 {
3204  Index i;
3205 
3206  /*
3207  * Careful here: at proc_exit we need extra cleanup, not just
3208  * xact_temporary files.
3209  */
3210  if (isProcExit || have_xact_temporary_files)
3211  {
3212  Assert(FileIsNotOpen(0)); /* Make sure ring not corrupted */
3213  for (i = 1; i < SizeVfdCache; i++)
3214  {
3215  unsigned short fdstate = VfdCache[i].fdstate;
3216 
3217  if (((fdstate & FD_DELETE_AT_CLOSE) || (fdstate & FD_CLOSE_AT_EOXACT)) &&
3218  VfdCache[i].fileName != NULL)
3219  {
3220  /*
3221  * If we're in the process of exiting a backend process, close
3222  * all temporary files. Otherwise, only close temporary files
3223  * local to the current transaction. They should be closed by
3224  * the ResourceOwner mechanism already, so this is just a
3225  * debugging cross-check.
3226  */
3227  if (isProcExit)
3228  FileClose(i);
3229  else if (fdstate & FD_CLOSE_AT_EOXACT)
3230  {
3231  elog(WARNING,
3232  "temporary file %s not closed at end-of-transaction",
3233  VfdCache[i].fileName);
3234  FileClose(i);
3235  }
3236  }
3237  }
3238 
3239  have_xact_temporary_files = false;
3240  }
3241 
3242  /* Complain if any allocated files remain open at commit. */
3243  if (isCommit && numAllocatedDescs > 0)
3244  elog(WARNING, "%d temporary files and directories not closed at end-of-transaction",
3246 
3247  /* Clean up "allocated" stdio files, dirs and fds. */
3248  while (numAllocatedDescs > 0)
3249  FreeDesc(&allocatedDescs[0]);
3250 }
3251 
3252 
3253 /*
3254  * Remove temporary and temporary relation files left over from a prior
3255  * postmaster session
3256  *
3257  * This should be called during postmaster startup. It will forcibly
3258  * remove any leftover files created by OpenTemporaryFile and any leftover
3259  * temporary relation files created by mdcreate.
3260  *
3261  * During post-backend-crash restart cycle, this routine is called when
3262  * remove_temp_files_after_crash GUC is enabled. Multiple crashes while
3263  * queries are using temp files could result in useless storage usage that can
3264  * only be reclaimed by a service restart. The argument against enabling it is
3265  * that someone might want to examine the temporary files for debugging
3266  * purposes. This does however mean that OpenTemporaryFile had better allow for
3267  * collision with an existing temp file name.
3268  *
3269  * NOTE: this function and its subroutines generally report syscall failures
3270  * with ereport(LOG) and keep going. Removing temp files is not so critical
3271  * that we should fail to start the database when we can't do it.
3272  */
3273 void
3275 {
3276  char temp_path[MAXPGPATH + 10 + sizeof(TABLESPACE_VERSION_DIRECTORY) + sizeof(PG_TEMP_FILES_DIR)];
3277  DIR *spc_dir;
3278  struct dirent *spc_de;
3279 
3280  /*
3281  * First process temp files in pg_default ($PGDATA/base)
3282  */
3283  snprintf(temp_path, sizeof(temp_path), "base/%s", PG_TEMP_FILES_DIR);
3284  RemovePgTempFilesInDir(temp_path, true, false);
3285  RemovePgTempRelationFiles("base");
3286 
3287  /*
3288  * Cycle through temp directories for all non-default tablespaces.
3289  */
3290  spc_dir = AllocateDir("pg_tblspc");
3291 
3292  while ((spc_de = ReadDirExtended(spc_dir, "pg_tblspc", LOG)) != NULL)
3293  {
3294  if (strcmp(spc_de->d_name, ".") == 0 ||
3295  strcmp(spc_de->d_name, "..") == 0)
3296  continue;
3297 
3298  snprintf(temp_path, sizeof(temp_path), "pg_tblspc/%s/%s/%s",
3300  RemovePgTempFilesInDir(temp_path, true, false);
3301 
3302  snprintf(temp_path, sizeof(temp_path), "pg_tblspc/%s/%s",
3304  RemovePgTempRelationFiles(temp_path);
3305  }
3306 
3307  FreeDir(spc_dir);
3308 
3309  /*
3310  * In EXEC_BACKEND case there is a pgsql_tmp directory at the top level of
3311  * DataDir as well. However, that is *not* cleaned here because doing so
3312  * would create a race condition. It's done separately, earlier in
3313  * postmaster startup.
3314  */
3315 }
3316 
3317 /*
3318  * Process one pgsql_tmp directory for RemovePgTempFiles.
3319  *
3320  * If missing_ok is true, it's all right for the named directory to not exist.
3321  * Any other problem results in a LOG message. (missing_ok should be true at
3322  * the top level, since pgsql_tmp directories are not created until needed.)
3323  *
3324  * At the top level, this should be called with unlink_all = false, so that
3325  * only files matching the temporary name prefix will be unlinked. When
3326  * recursing it will be called with unlink_all = true to unlink everything
3327  * under a top-level temporary directory.
3328  *
3329  * (These two flags could be replaced by one, but it seems clearer to keep
3330  * them separate.)
3331  */
3332 void
3333 RemovePgTempFilesInDir(const char *tmpdirname, bool missing_ok, bool unlink_all)
3334 {
3335  DIR *temp_dir;
3336  struct dirent *temp_de;
3337  char rm_path[MAXPGPATH * 2];
3338 
3339  temp_dir = AllocateDir(tmpdirname);
3340 
3341  if (temp_dir == NULL && errno == ENOENT && missing_ok)
3342  return;
3343 
3344  while ((temp_de = ReadDirExtended(temp_dir, tmpdirname, LOG)) != NULL)
3345  {
3346  if (strcmp(temp_de->d_name, ".") == 0 ||
3347  strcmp(temp_de->d_name, "..") == 0)
3348  continue;
3349 
3350  snprintf(rm_path, sizeof(rm_path), "%s/%s",
3351  tmpdirname, temp_de->d_name);
3352 
3353  if (unlink_all ||
3354  strncmp(temp_de->d_name,
3356  strlen(PG_TEMP_FILE_PREFIX)) == 0)
3357  {
3358  PGFileType type = get_dirent_type(rm_path, temp_de, false, LOG);
3359 
3360  if (type == PGFILETYPE_ERROR)
3361  continue;
3362  else if (type == PGFILETYPE_DIR)
3363  {
3364  /* recursively remove contents, then directory itself */
3365  RemovePgTempFilesInDir(rm_path, false, true);
3366 
3367  if (rmdir(rm_path) < 0)
3368  ereport(LOG,
3370  errmsg("could not remove directory \"%s\": %m",
3371  rm_path)));
3372  }
3373  else
3374  {
3375  if (unlink(rm_path) < 0)
3376  ereport(LOG,
3378  errmsg("could not remove file \"%s\": %m",
3379  rm_path)));
3380  }
3381  }
3382  else
3383  ereport(LOG,
3384  (errmsg("unexpected file found in temporary-files directory: \"%s\"",
3385  rm_path)));
3386  }
3387 
3388  FreeDir(temp_dir);
3389 }
3390 
3391 /* Process one tablespace directory, look for per-DB subdirectories */
3392 static void
3393 RemovePgTempRelationFiles(const char *tsdirname)
3394 {
3395  DIR *ts_dir;
3396  struct dirent *de;
3397  char dbspace_path[MAXPGPATH * 2];
3398 
3399  ts_dir = AllocateDir(tsdirname);
3400 
3401  while ((de = ReadDirExtended(ts_dir, tsdirname, LOG)) != NULL)
3402  {
3403  /*
3404  * We're only interested in the per-database directories, which have
3405  * numeric names. Note that this code will also (properly) ignore "."
3406  * and "..".
3407  */
3408  if (strspn(de->d_name, "0123456789") != strlen(de->d_name))
3409  continue;
3410 
3411  snprintf(dbspace_path, sizeof(dbspace_path), "%s/%s",
3412  tsdirname, de->d_name);
3413  RemovePgTempRelationFilesInDbspace(dbspace_path);
3414  }
3415 
3416  FreeDir(ts_dir);
3417 }
3418 
3419 /* Process one per-dbspace directory for RemovePgTempRelationFiles */
3420 static void
3421 RemovePgTempRelationFilesInDbspace(const char *dbspacedirname)
3422 {
3423  DIR *dbspace_dir;
3424  struct dirent *de;
3425  char rm_path[MAXPGPATH * 2];
3426 
3427  dbspace_dir = AllocateDir(dbspacedirname);
3428 
3429  while ((de = ReadDirExtended(dbspace_dir, dbspacedirname, LOG)) != NULL)
3430  {
3431  if (!looks_like_temp_rel_name(de->d_name))
3432  continue;
3433 
3434  snprintf(rm_path, sizeof(rm_path), "%s/%s",
3435  dbspacedirname, de->d_name);
3436 
3437  if (unlink(rm_path) < 0)
3438  ereport(LOG,
3440  errmsg("could not remove file \"%s\": %m",
3441  rm_path)));
3442  }
3443 
3444  FreeDir(dbspace_dir);
3445 }
3446 
3447 /* t<digits>_<digits>, or t<digits>_<digits>_<forkname> */
3448 bool
3450 {
3451  int pos;
3452  int savepos;
3453 
3454  /* Must start with "t". */
3455  if (name[0] != 't')
3456  return false;
3457 
3458  /* Followed by a non-empty string of digits and then an underscore. */
3459  for (pos = 1; isdigit((unsigned char) name[pos]); ++pos)
3460  ;
3461  if (pos == 1 || name[pos] != '_')
3462  return false;
3463 
3464  /* Followed by another nonempty string of digits. */
3465  for (savepos = ++pos; isdigit((unsigned char) name[pos]); ++pos)
3466  ;
3467  if (savepos == pos)
3468  return false;
3469 
3470  /* We might have _forkname or .segment or both. */
3471  if (name[pos] == '_')
3472  {
3473  int forkchar = forkname_chars(&name[pos + 1], NULL);
3474 
3475  if (forkchar <= 0)
3476  return false;
3477  pos += forkchar + 1;
3478  }
3479  if (name[pos] == '.')
3480  {
3481  int segchar;
3482 
3483  for (segchar = 1; isdigit((unsigned char) name[pos + segchar]); ++segchar)
3484  ;
3485  if (segchar <= 1)
3486  return false;
3487  pos += segchar;
3488  }
3489 
3490  /* Now we should be at the end. */
3491  if (name[pos] != '\0')
3492  return false;
3493  return true;
3494 }
3495 
3496 #ifdef HAVE_SYNCFS
3497 static void
3498 do_syncfs(const char *path)
3499 {
3500  int fd;
3501 
3502  ereport_startup_progress("syncing data directory (syncfs), elapsed time: %ld.%02d s, current path: %s",
3503  path);
3504 
3505  fd = OpenTransientFile(path, O_RDONLY);
3506  if (fd < 0)
3507  {
3508  ereport(LOG,
3510  errmsg("could not open file \"%s\": %m", path)));
3511  return;
3512  }
3513  if (syncfs(fd) < 0)
3514  ereport(LOG,
3516  errmsg("could not synchronize file system for file \"%s\": %m", path)));
3518 }
3519 #endif
3520 
3521 /*
3522  * Issue fsync recursively on PGDATA and all its contents, or issue syncfs for
3523  * all potential filesystem, depending on recovery_init_sync_method setting.
3524  *
3525  * We fsync regular files and directories wherever they are, but we
3526  * follow symlinks only for pg_wal and immediately under pg_tblspc.
3527  * Other symlinks are presumed to point at files we're not responsible
3528  * for fsyncing, and might not have privileges to write at all.
3529  *
3530  * Errors are logged but not considered fatal; that's because this is used
3531  * only during database startup, to deal with the possibility that there are
3532  * issued-but-unsynced writes pending against the data directory. We want to
3533  * ensure that such writes reach disk before anything that's done in the new
3534  * run. However, aborting on error would result in failure to start for
3535  * harmless cases such as read-only files in the data directory, and that's
3536  * not good either.
3537  *
3538  * Note that if we previously crashed due to a PANIC on fsync(), we'll be
3539  * rewriting all changes again during recovery.
3540  *
3541  * Note we assume we're chdir'd into PGDATA to begin with.
3542  */
3543 void
3545 {
3546  bool xlog_is_symlink;
3547 
3548  /* We can skip this whole thing if fsync is disabled. */
3549  if (!enableFsync)
3550  return;
3551 
3552  /*
3553  * If pg_wal is a symlink, we'll need to recurse into it separately,
3554  * because the first walkdir below will ignore it.
3555  */
3556  xlog_is_symlink = false;
3557 
3558  {
3559  struct stat st;
3560 
3561  if (lstat("pg_wal", &st) < 0)
3562  ereport(LOG,
3564  errmsg("could not stat file \"%s\": %m",
3565  "pg_wal")));
3566  else if (S_ISLNK(st.st_mode))
3567  xlog_is_symlink = true;
3568  }
3569 
3570 #ifdef HAVE_SYNCFS
3572  {
3573  DIR *dir;
3574  struct dirent *de;
3575 
3576  /*
3577  * On Linux, we don't have to open every single file one by one. We
3578  * can use syncfs() to sync whole filesystems. We only expect
3579  * filesystem boundaries to exist where we tolerate symlinks, namely
3580  * pg_wal and the tablespaces, so we call syncfs() for each of those
3581  * directories.
3582  */
3583 
3584  /* Prepare to report progress syncing the data directory via syncfs. */
3586 
3587  /* Sync the top level pgdata directory. */
3588  do_syncfs(".");
3589  /* If any tablespaces are configured, sync each of those. */
3590  dir = AllocateDir("pg_tblspc");
3591  while ((de = ReadDirExtended(dir, "pg_tblspc", LOG)))
3592  {
3593  char path[MAXPGPATH];
3594 
3595  if (strcmp(de->d_name, ".") == 0 || strcmp(de->d_name, "..") == 0)
3596  continue;
3597 
3598  snprintf(path, MAXPGPATH, "pg_tblspc/%s", de->d_name);
3599  do_syncfs(path);
3600  }
3601  FreeDir(dir);
3602  /* If pg_wal is a symlink, process that too. */
3603  if (xlog_is_symlink)
3604  do_syncfs("pg_wal");
3605  return;
3606  }
3607 #endif /* !HAVE_SYNCFS */
3608 
3609 #ifdef PG_FLUSH_DATA_WORKS
3610  /* Prepare to report progress of the pre-fsync phase. */
3612 
3613  /*
3614  * If possible, hint to the kernel that we're soon going to fsync the data
3615  * directory and its contents. Errors in this step are even less
3616  * interesting than normal, so log them only at DEBUG1.
3617  */
3618  walkdir(".", pre_sync_fname, false, DEBUG1);
3619  if (xlog_is_symlink)
3620  walkdir("pg_wal", pre_sync_fname, false, DEBUG1);
3621  walkdir("pg_tblspc", pre_sync_fname, true, DEBUG1);
3622 #endif
3623 
3624  /* Prepare to report progress syncing the data directory via fsync. */
3626 
3627  /*
3628  * Now we do the fsync()s in the same order.
3629  *
3630  * The main call ignores symlinks, so in addition to specially processing
3631  * pg_wal if it's a symlink, pg_tblspc has to be visited separately with
3632  * process_symlinks = true. Note that if there are any plain directories
3633  * in pg_tblspc, they'll get fsync'd twice. That's not an expected case
3634  * so we don't worry about optimizing it.
3635  */
3636  walkdir(".", datadir_fsync_fname, false, LOG);
3637  if (xlog_is_symlink)
3638  walkdir("pg_wal", datadir_fsync_fname, false, LOG);
3639  walkdir("pg_tblspc", datadir_fsync_fname, true, LOG);
3640 }
3641 
3642 /*
3643  * walkdir: recursively walk a directory, applying the action to each
3644  * regular file and directory (including the named directory itself).
3645  *
3646  * If process_symlinks is true, the action and recursion are also applied
3647  * to regular files and directories that are pointed to by symlinks in the
3648  * given directory; otherwise symlinks are ignored. Symlinks are always
3649  * ignored in subdirectories, ie we intentionally don't pass down the
3650  * process_symlinks flag to recursive calls.
3651  *
3652  * Errors are reported at level elevel, which might be ERROR or less.
3653  *
3654  * See also walkdir in file_utils.c, which is a frontend version of this
3655  * logic.
3656  */
3657 static void
3658 walkdir(const char *path,
3659  void (*action) (const char *fname, bool isdir, int elevel),
3660  bool process_symlinks,
3661  int elevel)
3662 {
3663  DIR *dir;
3664  struct dirent *de;
3665 
3666  dir = AllocateDir(path);
3667 
3668  while ((de = ReadDirExtended(dir, path, elevel)) != NULL)
3669  {
3670  char subpath[MAXPGPATH * 2];
3671 
3673 
3674  if (strcmp(de->d_name, ".") == 0 ||
3675  strcmp(de->d_name, "..") == 0)
3676  continue;
3677 
3678  snprintf(subpath, sizeof(subpath), "%s/%s", path, de->d_name);
3679 
3680  switch (get_dirent_type(subpath, de, process_symlinks, elevel))
3681  {
3682  case PGFILETYPE_REG:
3683  (*action) (subpath, false, elevel);
3684  break;
3685  case PGFILETYPE_DIR:
3686  walkdir(subpath, action, false, elevel);
3687  break;
3688  default:
3689 
3690  /*
3691  * Errors are already reported directly by get_dirent_type(),
3692  * and any remaining symlinks and unknown file types are
3693  * ignored.
3694  */
3695  break;
3696  }
3697  }
3698 
3699  FreeDir(dir); /* we ignore any error here */
3700 
3701  /*
3702  * It's important to fsync the destination directory itself as individual
3703  * file fsyncs don't guarantee that the directory entry for the file is
3704  * synced. However, skip this if AllocateDir failed; the action function
3705  * might not be robust against that.
3706  */
3707  if (dir)
3708  (*action) (path, true, elevel);
3709 }
3710 
3711 
3712 /*
3713  * Hint to the OS that it should get ready to fsync() this file.
3714  *
3715  * Ignores errors trying to open unreadable files, and logs other errors at a
3716  * caller-specified level.
3717  */
3718 #ifdef PG_FLUSH_DATA_WORKS
3719 
3720 static void
3721 pre_sync_fname(const char *fname, bool isdir, int elevel)
3722 {
3723  int fd;
3724 
3725  /* Don't try to flush directories, it'll likely just fail */
3726  if (isdir)
3727  return;
3728 
3729  ereport_startup_progress("syncing data directory (pre-fsync), elapsed time: %ld.%02d s, current path: %s",
3730  fname);
3731 
3732  fd = OpenTransientFile(fname, O_RDONLY | PG_BINARY);
3733 
3734  if (fd < 0)
3735  {
3736  if (errno == EACCES)
3737  return;
3738  ereport(elevel,
3740  errmsg("could not open file \"%s\": %m", fname)));
3741  return;
3742  }
3743 
3744  /*
3745  * pg_flush_data() ignores errors, which is ok because this is only a
3746  * hint.
3747  */
3748  pg_flush_data(fd, 0, 0);
3749 
3750  if (CloseTransientFile(fd) != 0)
3751  ereport(elevel,
3753  errmsg("could not close file \"%s\": %m", fname)));
3754 }
3755 
3756 #endif /* PG_FLUSH_DATA_WORKS */
3757 
3758 static void
3759 datadir_fsync_fname(const char *fname, bool isdir, int elevel)
3760 {
3761  ereport_startup_progress("syncing data directory (fsync), elapsed time: %ld.%02d s, current path: %s",
3762  fname);
3763 
3764  /*
3765  * We want to silently ignoring errors about unreadable files. Pass that
3766  * desire on to fsync_fname_ext().
3767  */
3768  fsync_fname_ext(fname, isdir, true, elevel);
3769 }
3770 
3771 static void
3772 unlink_if_exists_fname(const char *fname, bool isdir, int elevel)
3773 {
3774  if (isdir)
3775  {
3776  if (rmdir(fname) != 0 && errno != ENOENT)
3777  ereport(elevel,
3779  errmsg("could not remove directory \"%s\": %m", fname)));
3780  }
3781  else
3782  {
3783  /* Use PathNameDeleteTemporaryFile to report filesize */
3784  PathNameDeleteTemporaryFile(fname, false);
3785  }
3786 }
3787 
3788 /*
3789  * fsync_fname_ext -- Try to fsync a file or directory
3790  *
3791  * If ignore_perm is true, ignore errors upon trying to open unreadable
3792  * files. Logs other errors at a caller-specified level.
3793  *
3794  * Returns 0 if the operation succeeded, -1 otherwise.
3795  */
3796 int
3797 fsync_fname_ext(const char *fname, bool isdir, bool ignore_perm, int elevel)
3798 {
3799  int fd;
3800  int flags;
3801  int returncode;
3802 
3803  /*
3804  * Some OSs require directories to be opened read-only whereas other
3805  * systems don't allow us to fsync files opened read-only; so we need both
3806  * cases here. Using O_RDWR will cause us to fail to fsync files that are
3807  * not writable by our userid, but we assume that's OK.
3808  */
3809  flags = PG_BINARY;
3810  if (!isdir)
3811  flags |= O_RDWR;
3812  else
3813  flags |= O_RDONLY;
3814 
3815  fd = OpenTransientFile(fname, flags);
3816 
3817  /*
3818  * Some OSs don't allow us to open directories at all (Windows returns
3819  * EACCES), just ignore the error in that case. If desired also silently
3820  * ignoring errors about unreadable files. Log others.
3821  */
3822  if (fd < 0 && isdir && (errno == EISDIR || errno == EACCES))
3823  return 0;
3824  else if (fd < 0 && ignore_perm && errno == EACCES)
3825  return 0;
3826  else if (fd < 0)
3827  {
3828  ereport(elevel,
3830  errmsg("could not open file \"%s\": %m", fname)));
3831  return -1;
3832  }
3833 
3834  returncode = pg_fsync(fd);
3835 
3836  /*
3837  * Some OSes don't allow us to fsync directories at all, so we can ignore
3838  * those errors. Anything else needs to be logged.
3839  */
3840  if (returncode != 0 && !(isdir && (errno == EBADF || errno == EINVAL)))
3841  {
3842  int save_errno;
3843 
3844  /* close file upon error, might not be in transaction context */
3845  save_errno = errno;
3846  (void) CloseTransientFile(fd);
3847  errno = save_errno;
3848 
3849  ereport(elevel,
3851  errmsg("could not fsync file \"%s\": %m", fname)));
3852  return -1;
3853  }
3854 
3855  if (CloseTransientFile(fd) != 0)
3856  {
3857  ereport(elevel,
3859  errmsg("could not close file \"%s\": %m", fname)));
3860  return -1;
3861  }
3862 
3863  return 0;
3864 }
3865 
3866 /*
3867  * fsync_parent_path -- fsync the parent path of a file or directory
3868  *
3869  * This is aimed at making file operations persistent on disk in case of
3870  * an OS crash or power failure.
3871  */
3872 static int
3873 fsync_parent_path(const char *fname, int elevel)
3874 {
3875  char parentpath[MAXPGPATH];
3876 
3877  strlcpy(parentpath, fname, MAXPGPATH);
3878  get_parent_directory(parentpath);
3879 
3880  /*
3881  * get_parent_directory() returns an empty string if the input argument is
3882  * just a file name (see comments in path.c), so handle that as being the
3883  * current directory.
3884  */
3885  if (strlen(parentpath) == 0)
3886  strlcpy(parentpath, ".", MAXPGPATH);
3887 
3888  if (fsync_fname_ext(parentpath, true, false, elevel) != 0)
3889  return -1;
3890 
3891  return 0;
3892 }
3893 
3894 /*
3895  * Create a PostgreSQL data sub-directory
3896  *
3897  * The data directory itself, and most of its sub-directories, are created at
3898  * initdb time, but we do have some occasions when we create directories in
3899  * the backend (CREATE TABLESPACE, for example). In those cases, we want to
3900  * make sure that those directories are created consistently. Today, that means
3901  * making sure that the created directory has the correct permissions, which is
3902  * what pg_dir_create_mode tracks for us.
3903  *
3904  * Note that we also set the umask() based on what we understand the correct
3905  * permissions to be (see file_perm.c).
3906  *
3907  * For permissions other than the default, mkdir() can be used directly, but
3908  * be sure to consider carefully such cases -- a sub-directory with incorrect
3909  * permissions in a PostgreSQL data directory could cause backups and other
3910  * processes to fail.
3911  */
3912 int
3913 MakePGDirectory(const char *directoryName)
3914 {
3915  return mkdir(directoryName, pg_dir_create_mode);
3916 }
3917 
3918 /*
3919  * Return the passed-in error level, or PANIC if data_sync_retry is off.
3920  *
3921  * Failure to fsync any data file is cause for immediate panic, unless
3922  * data_sync_retry is enabled. Data may have been written to the operating
3923  * system and removed from our buffer pool already, and if we are running on
3924  * an operating system that forgets dirty data on write-back failure, there
3925  * may be only one copy of the data remaining: in the WAL. A later attempt to
3926  * fsync again might falsely report success. Therefore we must not allow any
3927  * further checkpoints to be attempted. data_sync_retry can in theory be
3928  * enabled on systems known not to drop dirty buffered data on write-back
3929  * failure (with the likely outcome that checkpoints will continue to fail
3930  * until the underlying problem is fixed).
3931  *
3932  * Any code that reports a failure from fsync() or related functions should
3933  * filter the error level with this function.
3934  */
3935 int
3936 data_sync_elevel(int elevel)
3937 {
3938  return data_sync_retry ? elevel : PANIC;
3939 }
3940 
3941 bool
3943 {
3944  bool result = true;
3945  int flags;
3946 
3947 #if PG_O_DIRECT == 0
3948  if (strcmp(*newval, "") != 0)
3949  {
3950  GUC_check_errdetail("\"debug_io_direct\" is not supported on this platform.");
3951  result = false;
3952  }
3953  flags = 0;
3954 #else
3955  List *elemlist;
3956  ListCell *l;
3957  char *rawstring;
3958 
3959  /* Need a modifiable copy of string */
3960  rawstring = pstrdup(*newval);
3961 
3962  if (!SplitGUCList(rawstring, ',', &elemlist))
3963  {
3964  GUC_check_errdetail("Invalid list syntax in parameter \"%s\"",
3965  "debug_io_direct");
3966  pfree(rawstring);
3967  list_free(elemlist);
3968  return false;
3969  }
3970 
3971  flags = 0;
3972  foreach(l, elemlist)
3973  {
3974  char *item = (char *) lfirst(l);
3975 
3976  if (pg_strcasecmp(item, "data") == 0)
3977  flags |= IO_DIRECT_DATA;
3978  else if (pg_strcasecmp(item, "wal") == 0)
3979  flags |= IO_DIRECT_WAL;
3980  else if (pg_strcasecmp(item, "wal_init") == 0)
3981  flags |= IO_DIRECT_WAL_INIT;
3982  else
3983  {
3984  GUC_check_errdetail("Invalid option \"%s\"", item);
3985  result = false;
3986  break;
3987  }
3988  }
3989 
3990  /*
3991  * It's possible to configure block sizes smaller than our assumed I/O
3992  * alignment size, which could result in invalid I/O requests.
3993  */
3994 #if XLOG_BLCKSZ < PG_IO_ALIGN_SIZE
3995  if (result && (flags & (IO_DIRECT_WAL | IO_DIRECT_WAL_INIT)))
3996  {
3997  GUC_check_errdetail("\"debug_io_direct\" is not supported for WAL because XLOG_BLCKSZ is too small");
3998  result = false;
3999  }
4000 #endif
4001 #if BLCKSZ < PG_IO_ALIGN_SIZE
4002  if (result && (flags & IO_DIRECT_DATA))
4003  {
4004  GUC_check_errdetail("\"debug_io_direct\" is not supported for data because BLCKSZ is too small");
4005  result = false;
4006  }
4007 #endif
4008 
4009  pfree(rawstring);
4010  list_free(elemlist);
4011 #endif
4012 
4013  if (!result)
4014  return result;
4015 
4016  /* Save the flags in *extra, for use by assign_debug_io_direct */
4017  *extra = guc_malloc(ERROR, sizeof(int));
4018  *((int *) *extra) = flags;
4019 
4020  return result;
4021 }
4022 
4023 extern void
4024 assign_debug_io_direct(const char *newval, void *extra)
4025 {
4026  int *flags = (int *) extra;
4027 
4028  io_direct_flags = *flags;
4029 }
4030 
4031 /* ResourceOwner callbacks */
4032 
4033 static void
4035 {
4036  File file = (File) DatumGetInt32(res);
4037  Vfd *vfdP;
4038 
4039  Assert(FileIsValid(file));
4040 
4041  vfdP = &VfdCache[file];
4042  vfdP->resowner = NULL;
4043 
4044  FileClose(file);
4045 }
4046 
4047 static char *
4049 {
4050  return psprintf("File %d", DatumGetInt32(res));
4051 }
void begin_startup_progress_phase(void)
Definition: startup.c:343
unsigned int uint32
Definition: c.h:506
#define Min(x, y)
Definition: c.h:1004
uint32 SubTransactionId
Definition: c.h:656
#define INT64_FORMAT
Definition: c.h:548
#define Assert(condition)
Definition: c.h:858
#define PG_BINARY
Definition: c.h:1273
unsigned int Index
Definition: c.h:614
#define MemSet(start, val, len)
Definition: c.h:1020
#define StaticAssertStmt(condition, errmessage)
Definition: c.h:938
int fdatasync(int fildes)
#define OidIsValid(objectId)
Definition: c.h:775
size_t Size
Definition: c.h:605
int closedir(DIR *)
Definition: dirent.c:127
struct dirent * readdir(DIR *)
Definition: dirent.c:78
DIR * opendir(const char *)
Definition: dirent.c:33
int errcode_for_file_access(void)
Definition: elog.c:880
int errdetail(const char *fmt,...)
Definition: elog.c:1203
int errcode(int sqlerrcode)
Definition: elog.c:857
int errmsg(const char *fmt,...)
Definition: elog.c:1070
#define LOG
Definition: elog.h:31
#define FATAL
Definition: elog.h:41
#define WARNING
Definition: elog.h:36
#define DEBUG2
Definition: elog.h:29
#define PANIC
Definition: elog.h:42
#define DEBUG1
Definition: elog.h:30
#define ERROR
Definition: elog.h:39
#define elog(elevel,...)
Definition: elog.h:224
#define ereport(elevel,...)
Definition: elog.h:149
struct dirent * ReadDir(DIR *dir, const char *dirname)
Definition: fd.c:2909
static int pg_ftruncate(int fd, off_t length)
Definition: fd.c:703
int max_files_per_process
Definition: fd.c:146
void pg_flush_data(int fd, off_t offset, off_t nbytes)
Definition: fd.c:525
int FileGetRawDesc(File file)
Definition: fd.c:2477
int MakePGDirectory(const char *directoryName)
Definition: fd.c:3913
int FreeDir(DIR *dir)
Definition: fd.c:2961
int recovery_init_sync_method
Definition: fd.c:165
static const ResourceOwnerDesc file_resowner_desc
Definition: fd.c:361
void FileWriteback(File file, off_t offset, off_t nbytes, uint32 wait_event_info)
Definition: fd.c:2110
int pg_fsync_no_writethrough(int fd)
Definition: fd.c:441
#define FD_MINFREE
Definition: fd.c:138
static int numTempTableSpaces
Definition: fd.c:289
static bool ReleaseLruFile(void)
Definition: fd.c:1382
int io_direct_flags
Definition: fd.c:168
FILE * AllocateFile(const char *name, const char *mode)
Definition: fd.c:2583
#define FD_DELETE_AT_CLOSE
Definition: fd.c:192
int BasicOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode)
Definition: fd.c:1109
static int maxAllocatedDescs
Definition: fd.c:268
static void Delete(File file)
Definition: fd.c:1268
static int FreeDesc(AllocateDesc *desc)
Definition: fd.c:2742
static long tempFileCounter
Definition: fd.c:280
static char * ResOwnerPrintFile(Datum res)
Definition: fd.c:4048
int durable_rename(const char *oldfile, const char *newfile, int elevel)
Definition: fd.c:782
static void ResourceOwnerForgetFile(ResourceOwner owner, File file)
Definition: fd.c:377
int GetTempTablespaces(Oid *tableSpaces, int numSpaces)
Definition: fd.c:3093
static int numAllocatedDescs
Definition: fd.c:267
File PathNameOpenTemporaryFile(const char *path, int mode)
Definition: fd.c:1901
static void LruDelete(File file)
Definition: fd.c:1287
int pg_fdatasync(int fd)
Definition: fd.c:480
#define FileIsValid(file)
Definition: fd.c:186
void assign_debug_io_direct(const char *newval, void *extra)
Definition: fd.c:4024
int FileSync(File file, uint32 wait_event_info)
Definition: fd.c:2297
static int nfile
Definition: fd.c:222
int CloseTransientFile(int fd)
Definition: fd.c:2809
#define DO_DB(A)
Definition: fd.c:180
int BasicOpenFile(const char *fileName, int fileFlags)
Definition: fd.c:1087
void closeAllVfds(void)
Definition: fd.c:3020
int max_safe_fds
Definition: fd.c:159
static File AllocateVfd(void)
Definition: fd.c:1414
File PathNameCreateTemporaryFile(const char *path, bool error_on_failure)
Definition: fd.c:1861
void PathNameDeleteTemporaryDir(const char *dirname)
Definition: fd.c:1691
int ClosePipeStream(FILE *file)
Definition: fd.c:2991
void AtEOXact_Files(bool isCommit)
Definition: fd.c:3165
int FileGetRawFlags(File file)
Definition: fd.c:2487
static Size SizeVfdCache
Definition: fd.c:217
static int nextTempTableSpace
Definition: fd.c:290
#define FD_CLOSE_AT_EOXACT
Definition: fd.c:193
int fsync_fname_ext(const char *fname, bool isdir, bool ignore_perm, int elevel)
Definition: fd.c:3797
static void unlink_if_exists_fname(const char *fname, bool isdir, int elevel)
Definition: fd.c:3772
static void ResOwnerReleaseFile(Datum res)
Definition: fd.c:4034
static void RemovePgTempRelationFiles(const char *tsdirname)
Definition: fd.c:3393
int FreeFile(FILE *file)
Definition: fd.c:2781
mode_t FileGetRawMode(File file)
Definition: fd.c:2497
static AllocateDesc * allocatedDescs
Definition: fd.c:269
static void count_usable_fds(int max_to_probe, int *usable_fds, int *already_open)
Definition: fd.c:964
static int FileAccess(File file)
Definition: fd.c:1492
static void FreeVfd(File file)
Definition: fd.c:1472
struct vfd Vfd
int pg_fsync_writethrough(int fd)
Definition: fd.c:461
void FileClose(File file)
Definition: fd.c:1978
FILE * OpenPipeStream(const char *command, const char *mode)
Definition: fd.c:2686
void ReleaseExternalFD(void)
Definition: fd.c:1239
#define FD_TEMP_FILE_LIMIT
Definition: fd.c:194
void RemovePgTempFilesInDir(const char *tmpdirname, bool missing_ok, bool unlink_all)
Definition: fd.c:3333
bool pg_file_exists(const char *name)
Definition: fd.c:503
void RemovePgTempFiles(void)
Definition: fd.c:3274
#define FileIsNotOpen(file)
Definition: fd.c:189
bool TempTablespacesAreSet(void)
Definition: fd.c:3078
void fsync_fname(const char *fname, bool isdir)
Definition: fd.c:756
int FileFallocate(File file, off_t offset, off_t amount, uint32 wait_event_info)
Definition: fd.c:2369
int FilePrefetch(File file, off_t offset, off_t amount, uint32 wait_event_info)
Definition: fd.c:2078
int data_sync_elevel(int elevel)
Definition: fd.c:3936
File PathNameOpenFile(const char *fileName, int fileFlags)
Definition: fd.c:1575
static void Insert(File file)
Definition: fd.c:1313
AllocateDescKind
Definition: fd.c:248
@ AllocateDescDir
Definition: fd.c:251
@ AllocateDescPipe
Definition: fd.c:250
@ AllocateDescFile
Definition: fd.c:249
@ AllocateDescRawFD
Definition: fd.c:252
Oid GetNextTempTableSpace(void)
Definition: fd.c:3111
File PathNameOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode)
Definition: fd.c:1588
static void datadir_fsync_fname(const char *fname, bool isdir, int elevel)
Definition: fd.c:3759
static void ReportTemporaryFileUsage(const char *path, off_t size)
Definition: fd.c:1528
static File OpenTemporaryFileInTablespace(Oid tblspcOid, bool rejectError)
Definition: fd.c:1804
bool AcquireExternalFD(void)
Definition: fd.c:1186
static void RegisterTemporaryFile(File file)
Definition: fd.c:1547
struct dirent * ReadDirExtended(DIR *dir, const char *dirname, int elevel)
Definition: fd.c:2924
#define NUM_RESERVED_FDS
Definition: fd.c:129
static Oid * tempTableSpaces
Definition: fd.c:288
static bool reserveAllocatedDesc(void)
Definition: fd.c:2508
void InitFileAccess(void)
Definition: fd.c:903
static void RemovePgTempRelationFilesInDbspace(const char *dbspacedirname)
Definition: fd.c:3421
File OpenTemporaryFile(bool interXact)
Definition: fd.c:1724
int durable_unlink(const char *fname, int elevel)
Definition: fd.c:872
static uint64 temporary_files_size
Definition: fd.c:236
void ReserveExternalFD(void)
Definition: fd.c:1221
char * FilePathName(File file)
Definition: fd.c:2461
bool looks_like_temp_rel_name(const char *name)
Definition: fd.c:3449
bool PathNameDeleteTemporaryFile(const char *path, bool error_on_failure)
Definition: fd.c:1932
void set_max_safe_fds(void)
Definition: fd.c:1044
int pg_fsync(int fd)
Definition: fd.c:386
static void CleanupTempFiles(bool isCommit, bool isProcExit)
Definition: fd.c:3202
#define VFD_CLOSED
Definition: fd.c:184
static bool have_xact_temporary_files
Definition: fd.c:228
static int LruInsert(File file)
Definition: fd.c:1335
static int numExternalFDs
Definition: fd.c:274
static int fsync_parent_path(const char *fname, int elevel)
Definition: fd.c:3873
void PathNameCreateTemporaryDir(const char *basedir, const char *directory)
Definition: fd.c:1660
void AtEOSubXact_Files(bool isCommit, SubTransactionId mySubid, SubTransactionId parentSubid)
Definition: fd.c:3132
int OpenTransientFile(const char *fileName, int fileFlags)
Definition: fd.c:2633
void InitTemporaryFileAccess(void)
Definition: fd.c:933
static Vfd * VfdCache
Definition: fd.c:216
int OpenTransientFilePerm(const char *fileName, int fileFlags, mode_t fileMode)
Definition: fd.c:2642
bool data_sync_retry
Definition: fd.c:162
static void ReleaseLruFiles(void)
Definition: fd.c:1404
ssize_t FileWriteV(File file, const struct iovec *iov, int iovcnt, off_t offset, uint32 wait_event_info)
Definition: fd.c:2192
void SyncDataDirectory(void)
Definition: fd.c:3544
int FileZero(File file, off_t offset, off_t amount, uint32 wait_event_info)
Definition: fd.c:2324
off_t FileSize(File file)
Definition: fd.c:2409
ssize_t FileReadV(File file, const struct iovec *iov, int iovcnt, off_t offset, uint32 wait_event_info)
Definition: fd.c:2136
int FileTruncate(File file, off_t offset, uint32 wait_event_info)
Definition: fd.c:2426
bool check_debug_io_direct(char **newval, void **extra, GucSource source)
Definition: fd.c:3942
static void ResourceOwnerRememberFile(ResourceOwner owner, File file)
Definition: fd.c:372
static void BeforeShmemExit_Files(int code, Datum arg)
Definition: fd.c:3179
static void walkdir(const char *path, void(*action)(const char *fname, bool isdir, int elevel), bool process_symlinks, int elevel)
Definition: fd.c:3658
int pg_truncate(const char *path, off_t length)
Definition: fd.c:720
void SetTempTablespaces(Oid *tableSpaces, int numSpaces)
Definition: fd.c:3049
DIR * AllocateDir(const char *dirname)
Definition: fd.c:2843
void TempTablespacePath(char *path, Oid tablespace)
Definition: fd.c:1779
#define IO_DIRECT_WAL
Definition: fd.h:55
#define IO_DIRECT_DATA
Definition: fd.h:54
#define IO_DIRECT_WAL_INIT
Definition: fd.h:56
int File
Definition: fd.h:51
#define PG_O_DIRECT
Definition: fd.h:97
int pg_file_create_mode
Definition: file_perm.c:19
int pg_dir_create_mode
Definition: file_perm.c:18
ssize_t pg_pwrite_zeros(int fd, size_t size, off_t offset)
Definition: file_utils.c:687
PGFileType get_dirent_type(const char *path, const struct dirent *de, bool look_through_symlinks, int elevel)
Definition: file_utils.c:525
#define PG_TEMP_FILES_DIR
Definition: file_utils.h:62
#define PG_TEMP_FILE_PREFIX
Definition: file_utils.h:63
PGFileType
Definition: file_utils.h:19
@ PGFILETYPE_DIR
Definition: file_utils.h:23
@ PGFILETYPE_REG
Definition: file_utils.h:22
@ PGFILETYPE_ERROR
Definition: file_utils.h:20
@ DATA_DIR_SYNC_METHOD_SYNCFS
Definition: file_utils.h:30
@ DATA_DIR_SYNC_METHOD_FSYNC
Definition: file_utils.h:29
int MyProcPid
Definition: globals.c:45
bool enableFsync
Definition: globals.c:126
Oid MyDatabaseTableSpace
Definition: globals.c:93
void * guc_malloc(int elevel, size_t size)
Definition: guc.c:640
#define newval
#define GUC_check_errdetail
Definition: guc.h:447
GucSource
Definition: guc.h:108
int temp_file_limit
Definition: guc_tables.c:535
int log_temp_files
Definition: guc_tables.c:530
#define realloc(a, b)
Definition: header.h:60
#define free(a)
Definition: header.h:65
#define malloc(a)
Definition: header.h:50
#define close(a)
Definition: win32.h:12
void before_shmem_exit(pg_on_exit_callback function, Datum arg)
Definition: ipc.c:337
int j
Definition: isn.c:74
int i
Definition: isn.c:73
static void const char fflush(stdout)
void list_free(List *list)
Definition: list.c:1546
Datum subpath(PG_FUNCTION_ARGS)
Definition: ltree_op.c:310
char * pstrdup(const char *in)
Definition: mcxt.c:1695
void pfree(void *pointer)
Definition: mcxt.c:1520
void * repalloc(void *pointer, Size size)
Definition: mcxt.c:1540
void * palloc(Size size)
Definition: mcxt.c:1316
#define MAP_FAILED
Definition: mem.h:45
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:122
void * arg
static char * basedir
static PgChecksumMode mode
Definition: pg_checksums.c:56
#define MAXPGPATH
static ssize_t pg_pwritev(int fd, const struct iovec *iov, int iovcnt, off_t offset)
Definition: pg_iovec.h:83
static ssize_t pg_preadv(int fd, const struct iovec *iov, int iovcnt, off_t offset)
Definition: pg_iovec.h:44
#define lfirst(lc)
Definition: pg_list.h:172
uint64 pg_prng_uint64_range(pg_prng_state *state, uint64 rmin, uint64 rmax)
Definition: pg_prng.c:144
pg_prng_state pg_global_prng_state
Definition: pg_prng.c:34
static rewind_source * source
Definition: pg_rewind.c:89
static char * buf
Definition: pg_test_fsync.c:73
char * tablespace
Definition: pgbench.c:216
void pgstat_report_tempfile(size_t filesize)
int pg_strcasecmp(const char *s1, const char *s2)
Definition: pgstrcasecmp.c:36
void get_parent_directory(char *path)
Definition: path.c:976
pqsigfunc pqsignal(int signo, pqsigfunc func)
#define snprintf
Definition: port.h:238
size_t strlcpy(char *dst, const char *src, size_t siz)
Definition: strlcpy.c:45
uintptr_t Datum
Definition: postgres.h:64
static Datum Int32GetDatum(int32 X)
Definition: postgres.h:212
static int32 DatumGetInt32(Datum X)
Definition: postgres.h:202
#define InvalidOid
Definition: postgres_ext.h:36
unsigned int Oid
Definition: postgres_ext.h:31
static int fd(const char *x, int i)
Definition: preproc-init.c:105
char * psprintf(const char *fmt,...)
Definition: psprintf.c:46
int forkname_chars(const char *str, ForkNumber *fork)
Definition: relpath.c:81
#define TABLESPACE_VERSION_DIRECTORY
Definition: relpath.h:33
ResourceOwner CurrentResourceOwner
Definition: resowner.c:165
void ResourceOwnerForget(ResourceOwner owner, Datum value, const ResourceOwnerDesc *kind)
Definition: resowner.c:554
void ResourceOwnerRemember(ResourceOwner owner, Datum value, const ResourceOwnerDesc *kind)
Definition: resowner.c:514
void ResourceOwnerEnlarge(ResourceOwner owner)
Definition: resowner.c:442
@ RESOURCE_RELEASE_AFTER_LOCKS
Definition: resowner.h:56
#define RELEASE_PRIO_FILES
Definition: resowner.h:76
void pg_usleep(long microsec)
Definition: signal.c:53
static pg_noinline void Size size
Definition: slab.c:607
static void error(void)
Definition: sql-dyntest.c:147
#define ereport_startup_progress(msg,...)
Definition: startup.h:18
SubTransactionId create_subid
Definition: fd.c:258
DIR * dir
Definition: fd.c:262
FILE * file
Definition: fd.c:261
int fd
Definition: fd.c:263
union AllocateDesc::@22 desc
AllocateDescKind kind
Definition: fd.c:257
Definition: dirent.c:26
Definition: pg_list.h:54
const char * name
Definition: resowner.h:93
Definition: dirent.h:10
char d_name[MAX_PATH]
Definition: dirent.h:15
__int64 st_size
Definition: win32_port.h:273
unsigned short st_mode
Definition: win32_port.h:268
Definition: fd.c:197
int fd
Definition: fd.c:198
int fileFlags
Definition: fd.c:207
File lruLessRecently
Definition: fd.c:203
File lruMoreRecently
Definition: fd.c:202
char * fileName
Definition: fd.c:205
ResourceOwner resowner
Definition: fd.c:200
unsigned short fdstate
Definition: fd.c:199
File nextFree
Definition: fd.c:201
mode_t fileMode
Definition: fd.c:208
off_t fileSize
Definition: fd.c:204
bool SplitGUCList(char *rawstring, char separator, List **namelist)
Definition: varlena.c:3705
static void pgstat_report_wait_start(uint32 wait_event_info)
Definition: wait_event.h:82
static void pgstat_report_wait_end(void)
Definition: wait_event.h:98
const char * type
const char * name
#define fsync(fd)
Definition: win32_port.h:85
#define stat
Definition: win32_port.h:284
#define SIG_DFL
Definition: win32_port.h:163
#define EINTR
Definition: win32_port.h:374
#define EOPNOTSUPP
Definition: win32_port.h:398
#define SIGPIPE
Definition: win32_port.h:173
#define lstat(path, sb)
Definition: win32_port.h:285
#define S_ISDIR(m)
Definition: win32_port.h:325
void _dosmaperr(unsigned long)
Definition: win32error.c:177
#define S_ISLNK(m)
Definition: win32_port.h:344
#define mkdir(a, b)
Definition: win32_port.h:80
#define fstat
Definition: win32_port.h:283
#define ftruncate(a, b)
Definition: win32_port.h:82
#define SIG_IGN
Definition: win32_port.h:165
#define O_CLOEXEC
Definition: win32_port.h:359
#define O_DSYNC
Definition: win32_port.h:352
SubTransactionId GetCurrentSubTransactionId(void)
Definition: xact.c:788
int wal_sync_method
Definition: xlog.c:130
@ WAL_SYNC_METHOD_FSYNC_WRITETHROUGH
Definition: xlog.h:27
static const char * directory
Definition: zic.c:634