Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * md.c
4 : * This code manages relations that reside on magnetic disk.
5 : *
6 : * Or at least, that was what the Berkeley folk had in mind when they named
7 : * this file. In reality, what this code provides is an interface from
8 : * the smgr API to Unix-like filesystem APIs, so it will work with any type
9 : * of device for which the operating system provides filesystem support.
10 : * It doesn't matter whether the bits are on spinning rust or some other
11 : * storage technology.
12 : *
13 : * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
14 : * Portions Copyright (c) 1994, Regents of the University of California
15 : *
16 : *
17 : * IDENTIFICATION
18 : * src/backend/storage/smgr/md.c
19 : *
20 : *-------------------------------------------------------------------------
21 : */
22 : #include "postgres.h"
23 :
24 : #include <unistd.h>
25 : #include <fcntl.h>
26 : #include <sys/file.h>
27 :
28 : #include "access/xlogutils.h"
29 : #include "commands/tablespace.h"
30 : #include "common/file_utils.h"
31 : #include "miscadmin.h"
32 : #include "pg_trace.h"
33 : #include "pgstat.h"
34 : #include "storage/bufmgr.h"
35 : #include "storage/fd.h"
36 : #include "storage/md.h"
37 : #include "storage/relfilelocator.h"
38 : #include "storage/smgr.h"
39 : #include "storage/sync.h"
40 : #include "utils/memutils.h"
41 :
42 : /*
43 : * The magnetic disk storage manager keeps track of open file
44 : * descriptors in its own descriptor pool. This is done to make it
45 : * easier to support relations that are larger than the operating
46 : * system's file size limit (often 2GBytes). In order to do that,
47 : * we break relations up into "segment" files that are each shorter than
48 : * the OS file size limit. The segment size is set by the RELSEG_SIZE
49 : * configuration constant in pg_config.h.
50 : *
51 : * On disk, a relation must consist of consecutively numbered segment
52 : * files in the pattern
53 : * -- Zero or more full segments of exactly RELSEG_SIZE blocks each
54 : * -- Exactly one partial segment of size 0 <= size < RELSEG_SIZE blocks
55 : * -- Optionally, any number of inactive segments of size 0 blocks.
56 : * The full and partial segments are collectively the "active" segments.
57 : * Inactive segments are those that once contained data but are currently
58 : * not needed because of an mdtruncate() operation. The reason for leaving
59 : * them present at size zero, rather than unlinking them, is that other
60 : * backends and/or the checkpointer might be holding open file references to
61 : * such segments. If the relation expands again after mdtruncate(), such
62 : * that a deactivated segment becomes active again, it is important that
63 : * such file references still be valid --- else data might get written
64 : * out to an unlinked old copy of a segment file that will eventually
65 : * disappear.
66 : *
67 : * File descriptors are stored in the per-fork md_seg_fds arrays inside
68 : * SMgrRelation. The length of these arrays is stored in md_num_open_segs.
69 : * Note that a fork's md_num_open_segs having a specific value does not
70 : * necessarily mean the relation doesn't have additional segments; we may
71 : * just not have opened the next segment yet. (We could not have "all
72 : * segments are in the array" as an invariant anyway, since another backend
73 : * could extend the relation while we aren't looking.) We do not have
74 : * entries for inactive segments, however; as soon as we find a partial
75 : * segment, we assume that any subsequent segments are inactive.
76 : *
77 : * The entire MdfdVec array is palloc'd in the MdCxt memory context.
78 : */
79 :
80 : typedef struct _MdfdVec
81 : {
82 : File mdfd_vfd; /* fd number in fd.c's pool */
83 : BlockNumber mdfd_segno; /* segment number, from 0 */
84 : } MdfdVec;
85 :
86 : static MemoryContext MdCxt; /* context for all MdfdVec objects */
87 :
88 :
89 : /* Populate a file tag describing an md.c segment file. */
90 : #define INIT_MD_FILETAG(a,xx_rlocator,xx_forknum,xx_segno) \
91 : ( \
92 : memset(&(a), 0, sizeof(FileTag)), \
93 : (a).handler = SYNC_HANDLER_MD, \
94 : (a).rlocator = (xx_rlocator), \
95 : (a).forknum = (xx_forknum), \
96 : (a).segno = (xx_segno) \
97 : )
98 :
99 :
100 : /*** behavior for mdopen & _mdfd_getseg ***/
101 : /* ereport if segment not present */
102 : #define EXTENSION_FAIL (1 << 0)
103 : /* return NULL if segment not present */
104 : #define EXTENSION_RETURN_NULL (1 << 1)
105 : /* create new segments as needed */
106 : #define EXTENSION_CREATE (1 << 2)
107 : /* create new segments if needed during recovery */
108 : #define EXTENSION_CREATE_RECOVERY (1 << 3)
109 : /*
110 : * Allow opening segments which are preceded by segments smaller than
111 : * RELSEG_SIZE, e.g. inactive segments (see above). Note that this breaks
112 : * mdnblocks() and related functionality henceforth - which currently is ok,
113 : * because this is only required in the checkpointer which never uses
114 : * mdnblocks().
115 : */
116 : #define EXTENSION_DONT_CHECK_SIZE (1 << 4)
117 : /* don't try to open a segment, if not already open */
118 : #define EXTENSION_DONT_OPEN (1 << 5)
119 :
120 :
121 : /* local routines */
122 : static void mdunlinkfork(RelFileLocatorBackend rlocator, ForkNumber forknum,
123 : bool isRedo);
124 : static MdfdVec *mdopenfork(SMgrRelation reln, ForkNumber forknum, int behavior);
125 : static void register_dirty_segment(SMgrRelation reln, ForkNumber forknum,
126 : MdfdVec *seg);
127 : static void register_unlink_segment(RelFileLocatorBackend rlocator, ForkNumber forknum,
128 : BlockNumber segno);
129 : static void register_forget_request(RelFileLocatorBackend rlocator, ForkNumber forknum,
130 : BlockNumber segno);
131 : static void _fdvec_resize(SMgrRelation reln,
132 : ForkNumber forknum,
133 : int nseg);
134 : static char *_mdfd_segpath(SMgrRelation reln, ForkNumber forknum,
135 : BlockNumber segno);
136 : static MdfdVec *_mdfd_openseg(SMgrRelation reln, ForkNumber forknum,
137 : BlockNumber segno, int oflags);
138 : static MdfdVec *_mdfd_getseg(SMgrRelation reln, ForkNumber forknum,
139 : BlockNumber blkno, bool skipFsync, int behavior);
140 : static BlockNumber _mdnblocks(SMgrRelation reln, ForkNumber forknum,
141 : MdfdVec *seg);
142 :
143 : static inline int
144 2077274 : _mdfd_open_flags(void)
145 : {
146 2077274 : int flags = O_RDWR | PG_BINARY;
147 :
148 2077274 : if (io_direct_flags & IO_DIRECT_DATA)
149 658 : flags |= PG_O_DIRECT;
150 :
151 2077274 : return flags;
152 : }
153 :
154 : /*
155 : * mdinit() -- Initialize private state for magnetic disk storage manager.
156 : */
157 : void
158 29892 : mdinit(void)
159 : {
160 29892 : MdCxt = AllocSetContextCreate(TopMemoryContext,
161 : "MdSmgr",
162 : ALLOCSET_DEFAULT_SIZES);
163 29892 : }
164 :
165 : /*
166 : * mdexists() -- Does the physical file exist?
167 : *
168 : * Note: this will return true for lingering files, with pending deletions
169 : */
170 : bool
171 1909576 : mdexists(SMgrRelation reln, ForkNumber forknum)
172 : {
173 : /*
174 : * Close it first, to ensure that we notice if the fork has been unlinked
175 : * since we opened it. As an optimization, we can skip that in recovery,
176 : * which already closes relations when dropping them.
177 : */
178 1909576 : if (!InRecovery)
179 847066 : mdclose(reln, forknum);
180 :
181 1909576 : return (mdopenfork(reln, forknum, EXTENSION_RETURN_NULL) != NULL);
182 : }
183 :
184 : /*
185 : * mdcreate() -- Create a new relation on magnetic disk.
186 : *
187 : * If isRedo is true, it's okay for the relation to exist already.
188 : */
189 : void
190 5489730 : mdcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo)
191 : {
192 : MdfdVec *mdfd;
193 : char *path;
194 : File fd;
195 :
196 5489730 : if (isRedo && reln->md_num_open_segs[forknum] > 0)
197 5206664 : return; /* created and opened already... */
198 :
199 : Assert(reln->md_num_open_segs[forknum] == 0);
200 :
201 : /*
202 : * We may be using the target table space for the first time in this
203 : * database, so create a per-database subdirectory if needed.
204 : *
205 : * XXX this is a fairly ugly violation of module layering, but this seems
206 : * to be the best place to put the check. Maybe TablespaceCreateDbspace
207 : * should be here and not in commands/tablespace.c? But that would imply
208 : * importing a lot of stuff that smgr.c oughtn't know, either.
209 : */
210 283066 : TablespaceCreateDbspace(reln->smgr_rlocator.locator.spcOid,
211 : reln->smgr_rlocator.locator.dbOid,
212 : isRedo);
213 :
214 283066 : path = relpath(reln->smgr_rlocator, forknum);
215 :
216 283066 : fd = PathNameOpenFile(path, _mdfd_open_flags() | O_CREAT | O_EXCL);
217 :
218 283066 : if (fd < 0)
219 : {
220 7942 : int save_errno = errno;
221 :
222 7942 : if (isRedo)
223 7942 : fd = PathNameOpenFile(path, _mdfd_open_flags());
224 7942 : if (fd < 0)
225 : {
226 : /* be sure to report the error reported by create, not open */
227 0 : errno = save_errno;
228 0 : ereport(ERROR,
229 : (errcode_for_file_access(),
230 : errmsg("could not create file \"%s\": %m", path)));
231 : }
232 : }
233 :
234 283066 : pfree(path);
235 :
236 283066 : _fdvec_resize(reln, forknum, 1);
237 283066 : mdfd = &reln->md_seg_fds[forknum][0];
238 283066 : mdfd->mdfd_vfd = fd;
239 283066 : mdfd->mdfd_segno = 0;
240 :
241 283066 : if (!SmgrIsTemp(reln))
242 276994 : register_dirty_segment(reln, forknum, mdfd);
243 : }
244 :
245 : /*
246 : * mdunlink() -- Unlink a relation.
247 : *
248 : * Note that we're passed a RelFileLocatorBackend --- by the time this is called,
249 : * there won't be an SMgrRelation hashtable entry anymore.
250 : *
251 : * forknum can be a fork number to delete a specific fork, or InvalidForkNumber
252 : * to delete all forks.
253 : *
254 : * For regular relations, we don't unlink the first segment file of the rel,
255 : * but just truncate it to zero length, and record a request to unlink it after
256 : * the next checkpoint. Additional segments can be unlinked immediately,
257 : * however. Leaving the empty file in place prevents that relfilenumber
258 : * from being reused. The scenario this protects us from is:
259 : * 1. We delete a relation (and commit, and actually remove its file).
260 : * 2. We create a new relation, which by chance gets the same relfilenumber as
261 : * the just-deleted one (OIDs must've wrapped around for that to happen).
262 : * 3. We crash before another checkpoint occurs.
263 : * During replay, we would delete the file and then recreate it, which is fine
264 : * if the contents of the file were repopulated by subsequent WAL entries.
265 : * But if we didn't WAL-log insertions, but instead relied on fsyncing the
266 : * file after populating it (as we do at wal_level=minimal), the contents of
267 : * the file would be lost forever. By leaving the empty file until after the
268 : * next checkpoint, we prevent reassignment of the relfilenumber until it's
269 : * safe, because relfilenumber assignment skips over any existing file.
270 : *
271 : * Additional segments, if any, are truncated and then unlinked. The reason
272 : * for truncating is that other backends may still hold open FDs for these at
273 : * the smgr level, so that the kernel can't remove the file yet. We want to
274 : * reclaim the disk space right away despite that.
275 : *
276 : * We do not need to go through this dance for temp relations, though, because
277 : * we never make WAL entries for temp rels, and so a temp rel poses no threat
278 : * to the health of a regular rel that has taken over its relfilenumber.
279 : * The fact that temp rels and regular rels have different file naming
280 : * patterns provides additional safety. Other backends shouldn't have open
281 : * FDs for them, either.
282 : *
283 : * We also don't do it while performing a binary upgrade. There is no reuse
284 : * hazard in that case, since after a crash or even a simple ERROR, the
285 : * upgrade fails and the whole cluster must be recreated from scratch.
286 : * Furthermore, it is important to remove the files from disk immediately,
287 : * because we may be about to reuse the same relfilenumber.
288 : *
289 : * All the above applies only to the relation's main fork; other forks can
290 : * just be removed immediately, since they are not needed to prevent the
291 : * relfilenumber from being recycled. Also, we do not carefully
292 : * track whether other forks have been created or not, but just attempt to
293 : * unlink them unconditionally; so we should never complain about ENOENT.
294 : *
295 : * If isRedo is true, it's unsurprising for the relation to be already gone.
296 : * Also, we should remove the file immediately instead of queuing a request
297 : * for later, since during redo there's no possibility of creating a
298 : * conflicting relation.
299 : *
300 : * Note: we currently just never warn about ENOENT at all. We could warn in
301 : * the main-fork, non-isRedo case, but it doesn't seem worth the trouble.
302 : *
303 : * Note: any failure should be reported as WARNING not ERROR, because
304 : * we are usually not in a transaction anymore when this is called.
305 : */
306 : void
307 343016 : mdunlink(RelFileLocatorBackend rlocator, ForkNumber forknum, bool isRedo)
308 : {
309 : /* Now do the per-fork work */
310 343016 : if (forknum == InvalidForkNumber)
311 : {
312 0 : for (forknum = 0; forknum <= MAX_FORKNUM; forknum++)
313 0 : mdunlinkfork(rlocator, forknum, isRedo);
314 : }
315 : else
316 343016 : mdunlinkfork(rlocator, forknum, isRedo);
317 343016 : }
318 :
319 : /*
320 : * Truncate a file to release disk space.
321 : */
322 : static int
323 402968 : do_truncate(const char *path)
324 : {
325 : int save_errno;
326 : int ret;
327 :
328 402968 : ret = pg_truncate(path, 0);
329 :
330 : /* Log a warning here to avoid repetition in callers. */
331 402968 : if (ret < 0 && errno != ENOENT)
332 : {
333 0 : save_errno = errno;
334 0 : ereport(WARNING,
335 : (errcode_for_file_access(),
336 : errmsg("could not truncate file \"%s\": %m", path)));
337 0 : errno = save_errno;
338 : }
339 :
340 402968 : return ret;
341 : }
342 :
343 : static void
344 343016 : mdunlinkfork(RelFileLocatorBackend rlocator, ForkNumber forknum, bool isRedo)
345 : {
346 : char *path;
347 : int ret;
348 : int save_errno;
349 :
350 343016 : path = relpath(rlocator, forknum);
351 :
352 : /*
353 : * Truncate and then unlink the first segment, or just register a request
354 : * to unlink it later, as described in the comments for mdunlink().
355 : */
356 343016 : if (isRedo || IsBinaryUpgrade || forknum != MAIN_FORKNUM ||
357 71648 : RelFileLocatorBackendIsTemp(rlocator))
358 : {
359 277170 : if (!RelFileLocatorBackendIsTemp(rlocator))
360 : {
361 : /* Prevent other backends' fds from holding on to the disk space */
362 253962 : ret = do_truncate(path);
363 :
364 : /* Forget any pending sync requests for the first segment */
365 253962 : save_errno = errno;
366 253962 : register_forget_request(rlocator, forknum, 0 /* first seg */ );
367 253962 : errno = save_errno;
368 : }
369 : else
370 23208 : ret = 0;
371 :
372 : /* Next unlink the file, unless it was already found to be missing */
373 277170 : if (ret >= 0 || errno != ENOENT)
374 : {
375 40530 : ret = unlink(path);
376 40530 : if (ret < 0 && errno != ENOENT)
377 : {
378 0 : save_errno = errno;
379 0 : ereport(WARNING,
380 : (errcode_for_file_access(),
381 : errmsg("could not remove file \"%s\": %m", path)));
382 0 : errno = save_errno;
383 : }
384 : }
385 : }
386 : else
387 : {
388 : /* Prevent other backends' fds from holding on to the disk space */
389 65846 : ret = do_truncate(path);
390 :
391 : /* Register request to unlink first segment later */
392 65846 : save_errno = errno;
393 65846 : register_unlink_segment(rlocator, forknum, 0 /* first seg */ );
394 65846 : errno = save_errno;
395 : }
396 :
397 : /*
398 : * Delete any additional segments.
399 : *
400 : * Note that because we loop until getting ENOENT, we will correctly
401 : * remove all inactive segments as well as active ones. Ideally we'd
402 : * continue the loop until getting exactly that errno, but that risks an
403 : * infinite loop if the problem is directory-wide (for instance, if we
404 : * suddenly can't read the data directory itself). We compromise by
405 : * continuing after a non-ENOENT truncate error, but stopping after any
406 : * unlink error. If there is indeed a directory-wide problem, additional
407 : * unlink attempts wouldn't work anyway.
408 : */
409 343016 : if (ret >= 0 || errno != ENOENT)
410 : {
411 89232 : char *segpath = (char *) palloc(strlen(path) + 12);
412 : BlockNumber segno;
413 :
414 89232 : for (segno = 1;; segno++)
415 : {
416 89232 : sprintf(segpath, "%s.%u", path, segno);
417 :
418 89232 : if (!RelFileLocatorBackendIsTemp(rlocator))
419 : {
420 : /*
421 : * Prevent other backends' fds from holding on to the disk
422 : * space. We're done if we see ENOENT, though.
423 : */
424 83160 : if (do_truncate(segpath) < 0 && errno == ENOENT)
425 83160 : break;
426 :
427 : /*
428 : * Forget any pending sync requests for this segment before we
429 : * try to unlink.
430 : */
431 0 : register_forget_request(rlocator, forknum, segno);
432 : }
433 :
434 6072 : if (unlink(segpath) < 0)
435 : {
436 : /* ENOENT is expected after the last segment... */
437 6072 : if (errno != ENOENT)
438 0 : ereport(WARNING,
439 : (errcode_for_file_access(),
440 : errmsg("could not remove file \"%s\": %m", segpath)));
441 6072 : break;
442 : }
443 : }
444 89232 : pfree(segpath);
445 : }
446 :
447 343016 : pfree(path);
448 343016 : }
449 :
450 : /*
451 : * mdextend() -- Add a block to the specified relation.
452 : *
453 : * The semantics are nearly the same as mdwrite(): write at the
454 : * specified position. However, this is to be used for the case of
455 : * extending a relation (i.e., blocknum is at or beyond the current
456 : * EOF). Note that we assume writing a block beyond current EOF
457 : * causes intervening file space to become filled with zeroes.
458 : */
459 : void
460 214978 : mdextend(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
461 : const void *buffer, bool skipFsync)
462 : {
463 : off_t seekpos;
464 : int nbytes;
465 : MdfdVec *v;
466 :
467 : /* If this build supports direct I/O, the buffer must be I/O aligned. */
468 : if (PG_O_DIRECT != 0 && PG_IO_ALIGN_SIZE <= BLCKSZ)
469 : Assert((uintptr_t) buffer == TYPEALIGN(PG_IO_ALIGN_SIZE, buffer));
470 :
471 : /* This assert is too expensive to have on normally ... */
472 : #ifdef CHECK_WRITE_VS_EXTEND
473 : Assert(blocknum >= mdnblocks(reln, forknum));
474 : #endif
475 :
476 : /*
477 : * If a relation manages to grow to 2^32-1 blocks, refuse to extend it any
478 : * more --- we mustn't create a block whose number actually is
479 : * InvalidBlockNumber. (Note that this failure should be unreachable
480 : * because of upstream checks in bufmgr.c.)
481 : */
482 214978 : if (blocknum == InvalidBlockNumber)
483 0 : ereport(ERROR,
484 : (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
485 : errmsg("cannot extend file \"%s\" beyond %u blocks",
486 : relpath(reln->smgr_rlocator, forknum),
487 : InvalidBlockNumber)));
488 :
489 214978 : v = _mdfd_getseg(reln, forknum, blocknum, skipFsync, EXTENSION_CREATE);
490 :
491 214978 : seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
492 :
493 : Assert(seekpos < (off_t) BLCKSZ * RELSEG_SIZE);
494 :
495 214978 : if ((nbytes = FileWrite(v->mdfd_vfd, buffer, BLCKSZ, seekpos, WAIT_EVENT_DATA_FILE_EXTEND)) != BLCKSZ)
496 : {
497 0 : if (nbytes < 0)
498 0 : ereport(ERROR,
499 : (errcode_for_file_access(),
500 : errmsg("could not extend file \"%s\": %m",
501 : FilePathName(v->mdfd_vfd)),
502 : errhint("Check free disk space.")));
503 : /* short write: complain appropriately */
504 0 : ereport(ERROR,
505 : (errcode(ERRCODE_DISK_FULL),
506 : errmsg("could not extend file \"%s\": wrote only %d of %d bytes at block %u",
507 : FilePathName(v->mdfd_vfd),
508 : nbytes, BLCKSZ, blocknum),
509 : errhint("Check free disk space.")));
510 : }
511 :
512 214978 : if (!skipFsync && !SmgrIsTemp(reln))
513 56 : register_dirty_segment(reln, forknum, v);
514 :
515 : Assert(_mdnblocks(reln, forknum, v) <= ((BlockNumber) RELSEG_SIZE));
516 214978 : }
517 :
518 : /*
519 : * mdzeroextend() -- Add new zeroed out blocks to the specified relation.
520 : *
521 : * Similar to mdextend(), except the relation can be extended by multiple
522 : * blocks at once and the added blocks will be filled with zeroes.
523 : */
524 : void
525 371698 : mdzeroextend(SMgrRelation reln, ForkNumber forknum,
526 : BlockNumber blocknum, int nblocks, bool skipFsync)
527 : {
528 : MdfdVec *v;
529 371698 : BlockNumber curblocknum = blocknum;
530 371698 : int remblocks = nblocks;
531 :
532 : Assert(nblocks > 0);
533 :
534 : /* This assert is too expensive to have on normally ... */
535 : #ifdef CHECK_WRITE_VS_EXTEND
536 : Assert(blocknum >= mdnblocks(reln, forknum));
537 : #endif
538 :
539 : /*
540 : * If a relation manages to grow to 2^32-1 blocks, refuse to extend it any
541 : * more --- we mustn't create a block whose number actually is
542 : * InvalidBlockNumber or larger.
543 : */
544 371698 : if ((uint64) blocknum + nblocks >= (uint64) InvalidBlockNumber)
545 0 : ereport(ERROR,
546 : (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
547 : errmsg("cannot extend file \"%s\" beyond %u blocks",
548 : relpath(reln->smgr_rlocator, forknum),
549 : InvalidBlockNumber)));
550 :
551 743396 : while (remblocks > 0)
552 : {
553 371698 : BlockNumber segstartblock = curblocknum % ((BlockNumber) RELSEG_SIZE);
554 371698 : off_t seekpos = (off_t) BLCKSZ * segstartblock;
555 : int numblocks;
556 :
557 371698 : if (segstartblock + remblocks > RELSEG_SIZE)
558 0 : numblocks = RELSEG_SIZE - segstartblock;
559 : else
560 371698 : numblocks = remblocks;
561 :
562 371698 : v = _mdfd_getseg(reln, forknum, curblocknum, skipFsync, EXTENSION_CREATE);
563 :
564 : Assert(segstartblock < RELSEG_SIZE);
565 : Assert(segstartblock + numblocks <= RELSEG_SIZE);
566 :
567 : /*
568 : * If available and useful, use posix_fallocate() (via
569 : * FileFallocate()) to extend the relation. That's often more
570 : * efficient than using write(), as it commonly won't cause the kernel
571 : * to allocate page cache space for the extended pages.
572 : *
573 : * However, we don't use FileFallocate() for small extensions, as it
574 : * defeats delayed allocation on some filesystems. Not clear where
575 : * that decision should be made though? For now just use a cutoff of
576 : * 8, anything between 4 and 8 worked OK in some local testing.
577 : */
578 371698 : if (numblocks > 8)
579 : {
580 : int ret;
581 :
582 1000 : ret = FileFallocate(v->mdfd_vfd,
583 : seekpos, (off_t) BLCKSZ * numblocks,
584 : WAIT_EVENT_DATA_FILE_EXTEND);
585 1000 : if (ret != 0)
586 : {
587 0 : ereport(ERROR,
588 : errcode_for_file_access(),
589 : errmsg("could not extend file \"%s\" with FileFallocate(): %m",
590 : FilePathName(v->mdfd_vfd)),
591 : errhint("Check free disk space."));
592 : }
593 : }
594 : else
595 : {
596 : int ret;
597 :
598 : /*
599 : * Even if we don't want to use fallocate, we can still extend a
600 : * bit more efficiently than writing each 8kB block individually.
601 : * pg_pwrite_zeros() (via FileZero()) uses pg_pwritev_with_retry()
602 : * to avoid multiple writes or needing a zeroed buffer for the
603 : * whole length of the extension.
604 : */
605 370698 : ret = FileZero(v->mdfd_vfd,
606 : seekpos, (off_t) BLCKSZ * numblocks,
607 : WAIT_EVENT_DATA_FILE_EXTEND);
608 370698 : if (ret < 0)
609 0 : ereport(ERROR,
610 : errcode_for_file_access(),
611 : errmsg("could not extend file \"%s\": %m",
612 : FilePathName(v->mdfd_vfd)),
613 : errhint("Check free disk space."));
614 : }
615 :
616 371698 : if (!skipFsync && !SmgrIsTemp(reln))
617 354172 : register_dirty_segment(reln, forknum, v);
618 :
619 : Assert(_mdnblocks(reln, forknum, v) <= ((BlockNumber) RELSEG_SIZE));
620 :
621 371698 : remblocks -= numblocks;
622 371698 : curblocknum += numblocks;
623 : }
624 371698 : }
625 :
626 : /*
627 : * mdopenfork() -- Open one fork of the specified relation.
628 : *
629 : * Note we only open the first segment, when there are multiple segments.
630 : *
631 : * If first segment is not present, either ereport or return NULL according
632 : * to "behavior". We treat EXTENSION_CREATE the same as EXTENSION_FAIL;
633 : * EXTENSION_CREATE means it's OK to extend an existing relation, not to
634 : * invent one out of whole cloth.
635 : */
636 : static MdfdVec *
637 5818332 : mdopenfork(SMgrRelation reln, ForkNumber forknum, int behavior)
638 : {
639 : MdfdVec *mdfd;
640 : char *path;
641 : File fd;
642 :
643 : /* No work if already open */
644 5818332 : if (reln->md_num_open_segs[forknum] > 0)
645 4076798 : return &reln->md_seg_fds[forknum][0];
646 :
647 1741534 : path = relpath(reln->smgr_rlocator, forknum);
648 :
649 1741534 : fd = PathNameOpenFile(path, _mdfd_open_flags());
650 :
651 1741534 : if (fd < 0)
652 : {
653 629712 : if ((behavior & EXTENSION_RETURN_NULL) &&
654 629668 : FILE_POSSIBLY_DELETED(errno))
655 : {
656 629668 : pfree(path);
657 629668 : return NULL;
658 : }
659 44 : ereport(ERROR,
660 : (errcode_for_file_access(),
661 : errmsg("could not open file \"%s\": %m", path)));
662 : }
663 :
664 1111822 : pfree(path);
665 :
666 1111822 : _fdvec_resize(reln, forknum, 1);
667 1111822 : mdfd = &reln->md_seg_fds[forknum][0];
668 1111822 : mdfd->mdfd_vfd = fd;
669 1111822 : mdfd->mdfd_segno = 0;
670 :
671 : Assert(_mdnblocks(reln, forknum, mdfd) <= ((BlockNumber) RELSEG_SIZE));
672 :
673 1111822 : return mdfd;
674 : }
675 :
676 : /*
677 : * mdopen() -- Initialize newly-opened relation.
678 : */
679 : void
680 1562366 : mdopen(SMgrRelation reln)
681 : {
682 : /* mark it not open */
683 7811830 : for (int forknum = 0; forknum <= MAX_FORKNUM; forknum++)
684 6249464 : reln->md_num_open_segs[forknum] = 0;
685 1562366 : }
686 :
687 : /*
688 : * mdclose() -- Close the specified relation, if it isn't closed already.
689 : */
690 : void
691 6184138 : mdclose(SMgrRelation reln, ForkNumber forknum)
692 : {
693 6184138 : int nopensegs = reln->md_num_open_segs[forknum];
694 :
695 : /* No work if already closed */
696 6184138 : if (nopensegs == 0)
697 5319474 : return;
698 :
699 : /* close segments starting from the end */
700 1729328 : while (nopensegs > 0)
701 : {
702 864664 : MdfdVec *v = &reln->md_seg_fds[forknum][nopensegs - 1];
703 :
704 864664 : FileClose(v->mdfd_vfd);
705 864664 : _fdvec_resize(reln, forknum, nopensegs - 1);
706 864664 : nopensegs--;
707 : }
708 : }
709 :
710 : /*
711 : * mdprefetch() -- Initiate asynchronous read of the specified blocks of a relation
712 : */
713 : bool
714 242296 : mdprefetch(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
715 : int nblocks)
716 : {
717 : #ifdef USE_PREFETCH
718 :
719 : Assert((io_direct_flags & IO_DIRECT_DATA) == 0);
720 :
721 242296 : if ((uint64) blocknum + nblocks > (uint64) MaxBlockNumber + 1)
722 0 : return false;
723 :
724 484592 : while (nblocks > 0)
725 : {
726 : off_t seekpos;
727 : MdfdVec *v;
728 : int nblocks_this_segment;
729 :
730 242296 : v = _mdfd_getseg(reln, forknum, blocknum, false,
731 242296 : InRecovery ? EXTENSION_RETURN_NULL : EXTENSION_FAIL);
732 242296 : if (v == NULL)
733 0 : return false;
734 :
735 242296 : seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
736 :
737 : Assert(seekpos < (off_t) BLCKSZ * RELSEG_SIZE);
738 :
739 242296 : nblocks_this_segment =
740 242296 : Min(nblocks,
741 : RELSEG_SIZE - (blocknum % ((BlockNumber) RELSEG_SIZE)));
742 :
743 242296 : (void) FilePrefetch(v->mdfd_vfd, seekpos, BLCKSZ * nblocks_this_segment,
744 : WAIT_EVENT_DATA_FILE_PREFETCH);
745 :
746 242296 : blocknum += nblocks_this_segment;
747 242296 : nblocks -= nblocks_this_segment;
748 : }
749 : #endif /* USE_PREFETCH */
750 :
751 242296 : return true;
752 : }
753 :
754 : /*
755 : * Convert an array of buffer address into an array of iovec objects, and
756 : * return the number that were required. 'iov' must have enough space for up
757 : * to 'nblocks' elements, but the number used may be less depending on
758 : * merging. In the case of a run of fully contiguous buffers, a single iovec
759 : * will be populated that can be handled as a plain non-vectored I/O.
760 : */
761 : static int
762 3016742 : buffers_to_iovec(struct iovec *iov, void **buffers, int nblocks)
763 : {
764 : struct iovec *iovp;
765 : int iovcnt;
766 :
767 : Assert(nblocks >= 1);
768 :
769 : /* If this build supports direct I/O, buffers must be I/O aligned. */
770 6108276 : for (int i = 0; i < nblocks; ++i)
771 : {
772 : if (PG_O_DIRECT != 0 && PG_IO_ALIGN_SIZE <= BLCKSZ)
773 : Assert((uintptr_t) buffers[i] ==
774 : TYPEALIGN(PG_IO_ALIGN_SIZE, buffers[i]));
775 : }
776 :
777 : /* Start the first iovec off with the first buffer. */
778 3016742 : iovp = &iov[0];
779 3016742 : iovp->iov_base = buffers[0];
780 3016742 : iovp->iov_len = BLCKSZ;
781 3016742 : iovcnt = 1;
782 :
783 : /* Try to merge the rest. */
784 3091534 : for (int i = 1; i < nblocks; ++i)
785 : {
786 74792 : void *buffer = buffers[i];
787 :
788 74792 : if (((char *) iovp->iov_base + iovp->iov_len) == buffer)
789 : {
790 : /* Contiguous with the last iovec. */
791 70870 : iovp->iov_len += BLCKSZ;
792 : }
793 : else
794 : {
795 : /* Need a new iovec. */
796 3922 : iovp++;
797 3922 : iovp->iov_base = buffer;
798 3922 : iovp->iov_len = BLCKSZ;
799 3922 : iovcnt++;
800 : }
801 : }
802 :
803 3016742 : return iovcnt;
804 : }
805 :
806 : /*
807 : * mdreadv() -- Read the specified blocks from a relation.
808 : */
809 : void
810 2121580 : mdreadv(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
811 : void **buffers, BlockNumber nblocks)
812 : {
813 4243130 : while (nblocks > 0)
814 : {
815 : struct iovec iov[PG_IOV_MAX];
816 : int iovcnt;
817 : off_t seekpos;
818 : int nbytes;
819 : MdfdVec *v;
820 : BlockNumber nblocks_this_segment;
821 : size_t transferred_this_segment;
822 : size_t size_this_segment;
823 :
824 2121580 : v = _mdfd_getseg(reln, forknum, blocknum, false,
825 : EXTENSION_FAIL | EXTENSION_CREATE_RECOVERY);
826 :
827 2121550 : seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
828 :
829 : Assert(seekpos < (off_t) BLCKSZ * RELSEG_SIZE);
830 :
831 2121550 : nblocks_this_segment =
832 2121550 : Min(nblocks,
833 : RELSEG_SIZE - (blocknum % ((BlockNumber) RELSEG_SIZE)));
834 2121550 : nblocks_this_segment = Min(nblocks_this_segment, lengthof(iov));
835 :
836 2121550 : iovcnt = buffers_to_iovec(iov, buffers, nblocks_this_segment);
837 2121550 : size_this_segment = nblocks_this_segment * BLCKSZ;
838 2121550 : transferred_this_segment = 0;
839 :
840 : /*
841 : * Inner loop to continue after a short read. We'll keep going until
842 : * we hit EOF rather than assuming that a short read means we hit the
843 : * end.
844 : */
845 : for (;;)
846 : {
847 : TRACE_POSTGRESQL_SMGR_MD_READ_START(forknum, blocknum,
848 : reln->smgr_rlocator.locator.spcOid,
849 : reln->smgr_rlocator.locator.dbOid,
850 : reln->smgr_rlocator.locator.relNumber,
851 : reln->smgr_rlocator.backend);
852 2121550 : nbytes = FileReadV(v->mdfd_vfd, iov, iovcnt, seekpos,
853 : WAIT_EVENT_DATA_FILE_READ);
854 : TRACE_POSTGRESQL_SMGR_MD_READ_DONE(forknum, blocknum,
855 : reln->smgr_rlocator.locator.spcOid,
856 : reln->smgr_rlocator.locator.dbOid,
857 : reln->smgr_rlocator.locator.relNumber,
858 : reln->smgr_rlocator.backend,
859 : nbytes,
860 : size_this_segment - transferred_this_segment);
861 :
862 : #ifdef SIMULATE_SHORT_READ
863 : nbytes = Min(nbytes, 4096);
864 : #endif
865 :
866 2121550 : if (nbytes < 0)
867 0 : ereport(ERROR,
868 : (errcode_for_file_access(),
869 : errmsg("could not read blocks %u..%u in file \"%s\": %m",
870 : blocknum,
871 : blocknum + nblocks_this_segment - 1,
872 : FilePathName(v->mdfd_vfd))));
873 :
874 2121550 : if (nbytes == 0)
875 : {
876 : /*
877 : * We are at or past EOF, or we read a partial block at EOF.
878 : * Normally this is an error; upper levels should never try to
879 : * read a nonexistent block. However, if zero_damaged_pages
880 : * is ON or we are InRecovery, we should instead return zeroes
881 : * without complaining. This allows, for example, the case of
882 : * trying to update a block that was later truncated away.
883 : */
884 0 : if (zero_damaged_pages || InRecovery)
885 : {
886 0 : for (BlockNumber i = transferred_this_segment / BLCKSZ;
887 : i < nblocks_this_segment;
888 0 : ++i)
889 0 : memset(buffers[i], 0, BLCKSZ);
890 0 : break;
891 : }
892 : else
893 0 : ereport(ERROR,
894 : (errcode(ERRCODE_DATA_CORRUPTED),
895 : errmsg("could not read blocks %u..%u in file \"%s\": read only %zu of %zu bytes",
896 : blocknum,
897 : blocknum + nblocks_this_segment - 1,
898 : FilePathName(v->mdfd_vfd),
899 : transferred_this_segment,
900 : size_this_segment)));
901 : }
902 :
903 : /* One loop should usually be enough. */
904 2121550 : transferred_this_segment += nbytes;
905 : Assert(transferred_this_segment <= size_this_segment);
906 2121550 : if (transferred_this_segment == size_this_segment)
907 2121550 : break;
908 :
909 : /* Adjust position and vectors after a short read. */
910 0 : seekpos += nbytes;
911 0 : iovcnt = compute_remaining_iovec(iov, iov, iovcnt, nbytes);
912 : }
913 :
914 2121550 : nblocks -= nblocks_this_segment;
915 2121550 : buffers += nblocks_this_segment;
916 2121550 : blocknum += nblocks_this_segment;
917 : }
918 2121550 : }
919 :
920 : /*
921 : * mdwritev() -- Write the supplied blocks at the appropriate location.
922 : *
923 : * This is to be used only for updating already-existing blocks of a
924 : * relation (ie, those before the current EOF). To extend a relation,
925 : * use mdextend().
926 : */
927 : void
928 895192 : mdwritev(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
929 : const void **buffers, BlockNumber nblocks, bool skipFsync)
930 : {
931 : /* This assert is too expensive to have on normally ... */
932 : #ifdef CHECK_WRITE_VS_EXTEND
933 : Assert(blocknum < mdnblocks(reln, forknum));
934 : #endif
935 :
936 1790384 : while (nblocks > 0)
937 : {
938 : struct iovec iov[PG_IOV_MAX];
939 : int iovcnt;
940 : off_t seekpos;
941 : int nbytes;
942 : MdfdVec *v;
943 : BlockNumber nblocks_this_segment;
944 : size_t transferred_this_segment;
945 : size_t size_this_segment;
946 :
947 895192 : v = _mdfd_getseg(reln, forknum, blocknum, skipFsync,
948 : EXTENSION_FAIL | EXTENSION_CREATE_RECOVERY);
949 :
950 895192 : seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
951 :
952 : Assert(seekpos < (off_t) BLCKSZ * RELSEG_SIZE);
953 :
954 895192 : nblocks_this_segment =
955 895192 : Min(nblocks,
956 : RELSEG_SIZE - (blocknum % ((BlockNumber) RELSEG_SIZE)));
957 895192 : nblocks_this_segment = Min(nblocks_this_segment, lengthof(iov));
958 :
959 895192 : iovcnt = buffers_to_iovec(iov, (void **) buffers, nblocks_this_segment);
960 895192 : size_this_segment = nblocks_this_segment * BLCKSZ;
961 895192 : transferred_this_segment = 0;
962 :
963 : /*
964 : * Inner loop to continue after a short write. If the reason is that
965 : * we're out of disk space, a future attempt should get an ENOSPC
966 : * error from the kernel.
967 : */
968 : for (;;)
969 : {
970 : TRACE_POSTGRESQL_SMGR_MD_WRITE_START(forknum, blocknum,
971 : reln->smgr_rlocator.locator.spcOid,
972 : reln->smgr_rlocator.locator.dbOid,
973 : reln->smgr_rlocator.locator.relNumber,
974 : reln->smgr_rlocator.backend);
975 895192 : nbytes = FileWriteV(v->mdfd_vfd, iov, iovcnt, seekpos,
976 : WAIT_EVENT_DATA_FILE_WRITE);
977 : TRACE_POSTGRESQL_SMGR_MD_WRITE_DONE(forknum, blocknum,
978 : reln->smgr_rlocator.locator.spcOid,
979 : reln->smgr_rlocator.locator.dbOid,
980 : reln->smgr_rlocator.locator.relNumber,
981 : reln->smgr_rlocator.backend,
982 : nbytes,
983 : size_this_segment - transferred_this_segment);
984 :
985 : #ifdef SIMULATE_SHORT_WRITE
986 : nbytes = Min(nbytes, 4096);
987 : #endif
988 :
989 895192 : if (nbytes < 0)
990 : {
991 0 : bool enospc = errno == ENOSPC;
992 :
993 0 : ereport(ERROR,
994 : (errcode_for_file_access(),
995 : errmsg("could not write blocks %u..%u in file \"%s\": %m",
996 : blocknum,
997 : blocknum + nblocks_this_segment - 1,
998 : FilePathName(v->mdfd_vfd)),
999 : enospc ? errhint("Check free disk space.") : 0));
1000 : }
1001 :
1002 : /* One loop should usually be enough. */
1003 895192 : transferred_this_segment += nbytes;
1004 : Assert(transferred_this_segment <= size_this_segment);
1005 895192 : if (transferred_this_segment == size_this_segment)
1006 895192 : break;
1007 :
1008 : /* Adjust position and iovecs after a short write. */
1009 0 : seekpos += nbytes;
1010 0 : iovcnt = compute_remaining_iovec(iov, iov, iovcnt, nbytes);
1011 : }
1012 :
1013 895192 : if (!skipFsync && !SmgrIsTemp(reln))
1014 893292 : register_dirty_segment(reln, forknum, v);
1015 :
1016 895192 : nblocks -= nblocks_this_segment;
1017 895192 : buffers += nblocks_this_segment;
1018 895192 : blocknum += nblocks_this_segment;
1019 : }
1020 895192 : }
1021 :
1022 :
1023 : /*
1024 : * mdwriteback() -- Tell the kernel to write pages back to storage.
1025 : *
1026 : * This accepts a range of blocks because flushing several pages at once is
1027 : * considerably more efficient than doing so individually.
1028 : */
1029 : void
1030 134534 : mdwriteback(SMgrRelation reln, ForkNumber forknum,
1031 : BlockNumber blocknum, BlockNumber nblocks)
1032 : {
1033 : Assert((io_direct_flags & IO_DIRECT_DATA) == 0);
1034 :
1035 : /*
1036 : * Issue flush requests in as few requests as possible; have to split at
1037 : * segment boundaries though, since those are actually separate files.
1038 : */
1039 268208 : while (nblocks > 0)
1040 : {
1041 134534 : BlockNumber nflush = nblocks;
1042 : off_t seekpos;
1043 : MdfdVec *v;
1044 : int segnum_start,
1045 : segnum_end;
1046 :
1047 134534 : v = _mdfd_getseg(reln, forknum, blocknum, true /* not used */ ,
1048 : EXTENSION_DONT_OPEN);
1049 :
1050 : /*
1051 : * We might be flushing buffers of already removed relations, that's
1052 : * ok, just ignore that case. If the segment file wasn't open already
1053 : * (ie from a recent mdwrite()), then we don't want to re-open it, to
1054 : * avoid a race with PROCSIGNAL_BARRIER_SMGRRELEASE that might leave
1055 : * us with a descriptor to a file that is about to be unlinked.
1056 : */
1057 134534 : if (!v)
1058 860 : return;
1059 :
1060 : /* compute offset inside the current segment */
1061 133674 : segnum_start = blocknum / RELSEG_SIZE;
1062 :
1063 : /* compute number of desired writes within the current segment */
1064 133674 : segnum_end = (blocknum + nblocks - 1) / RELSEG_SIZE;
1065 133674 : if (segnum_start != segnum_end)
1066 0 : nflush = RELSEG_SIZE - (blocknum % ((BlockNumber) RELSEG_SIZE));
1067 :
1068 : Assert(nflush >= 1);
1069 : Assert(nflush <= nblocks);
1070 :
1071 133674 : seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
1072 :
1073 133674 : FileWriteback(v->mdfd_vfd, seekpos, (off_t) BLCKSZ * nflush, WAIT_EVENT_DATA_FILE_FLUSH);
1074 :
1075 133674 : nblocks -= nflush;
1076 133674 : blocknum += nflush;
1077 : }
1078 : }
1079 :
1080 : /*
1081 : * mdnblocks() -- Get the number of blocks stored in a relation.
1082 : *
1083 : * Important side effect: all active segments of the relation are opened
1084 : * and added to the md_seg_fds array. If this routine has not been
1085 : * called, then only segments up to the last one actually touched
1086 : * are present in the array.
1087 : */
1088 : BlockNumber
1089 3566506 : mdnblocks(SMgrRelation reln, ForkNumber forknum)
1090 : {
1091 : MdfdVec *v;
1092 : BlockNumber nblocks;
1093 : BlockNumber segno;
1094 :
1095 3566506 : mdopenfork(reln, forknum, EXTENSION_FAIL);
1096 :
1097 : /* mdopen has opened the first segment */
1098 : Assert(reln->md_num_open_segs[forknum] > 0);
1099 :
1100 : /*
1101 : * Start from the last open segments, to avoid redundant seeks. We have
1102 : * previously verified that these segments are exactly RELSEG_SIZE long,
1103 : * and it's useless to recheck that each time.
1104 : *
1105 : * NOTE: this assumption could only be wrong if another backend has
1106 : * truncated the relation. We rely on higher code levels to handle that
1107 : * scenario by closing and re-opening the md fd, which is handled via
1108 : * relcache flush. (Since the checkpointer doesn't participate in
1109 : * relcache flush, it could have segment entries for inactive segments;
1110 : * that's OK because the checkpointer never needs to compute relation
1111 : * size.)
1112 : */
1113 3566468 : segno = reln->md_num_open_segs[forknum] - 1;
1114 3566468 : v = &reln->md_seg_fds[forknum][segno];
1115 :
1116 : for (;;)
1117 : {
1118 3566468 : nblocks = _mdnblocks(reln, forknum, v);
1119 3566468 : if (nblocks > ((BlockNumber) RELSEG_SIZE))
1120 0 : elog(FATAL, "segment too big");
1121 3566468 : if (nblocks < ((BlockNumber) RELSEG_SIZE))
1122 3566468 : return (segno * ((BlockNumber) RELSEG_SIZE)) + nblocks;
1123 :
1124 : /*
1125 : * If segment is exactly RELSEG_SIZE, advance to next one.
1126 : */
1127 0 : segno++;
1128 :
1129 : /*
1130 : * We used to pass O_CREAT here, but that has the disadvantage that it
1131 : * might create a segment which has vanished through some operating
1132 : * system misadventure. In such a case, creating the segment here
1133 : * undermines _mdfd_getseg's attempts to notice and report an error
1134 : * upon access to a missing segment.
1135 : */
1136 0 : v = _mdfd_openseg(reln, forknum, segno, 0);
1137 0 : if (v == NULL)
1138 0 : return segno * ((BlockNumber) RELSEG_SIZE);
1139 : }
1140 : }
1141 :
1142 : /*
1143 : * mdtruncate() -- Truncate relation to specified number of blocks.
1144 : */
1145 : void
1146 1520 : mdtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks)
1147 : {
1148 : BlockNumber curnblk;
1149 : BlockNumber priorblocks;
1150 : int curopensegs;
1151 :
1152 : /*
1153 : * NOTE: mdnblocks makes sure we have opened all active segments, so that
1154 : * truncation loop will get them all!
1155 : */
1156 1520 : curnblk = mdnblocks(reln, forknum);
1157 1520 : if (nblocks > curnblk)
1158 : {
1159 : /* Bogus request ... but no complaint if InRecovery */
1160 0 : if (InRecovery)
1161 0 : return;
1162 0 : ereport(ERROR,
1163 : (errmsg("could not truncate file \"%s\" to %u blocks: it's only %u blocks now",
1164 : relpath(reln->smgr_rlocator, forknum),
1165 : nblocks, curnblk)));
1166 : }
1167 1520 : if (nblocks == curnblk)
1168 630 : return; /* no work */
1169 :
1170 : /*
1171 : * Truncate segments, starting at the last one. Starting at the end makes
1172 : * managing the memory for the fd array easier, should there be errors.
1173 : */
1174 890 : curopensegs = reln->md_num_open_segs[forknum];
1175 1780 : while (curopensegs > 0)
1176 : {
1177 : MdfdVec *v;
1178 :
1179 890 : priorblocks = (curopensegs - 1) * RELSEG_SIZE;
1180 :
1181 890 : v = &reln->md_seg_fds[forknum][curopensegs - 1];
1182 :
1183 890 : if (priorblocks > nblocks)
1184 : {
1185 : /*
1186 : * This segment is no longer active. We truncate the file, but do
1187 : * not delete it, for reasons explained in the header comments.
1188 : */
1189 0 : if (FileTruncate(v->mdfd_vfd, 0, WAIT_EVENT_DATA_FILE_TRUNCATE) < 0)
1190 0 : ereport(ERROR,
1191 : (errcode_for_file_access(),
1192 : errmsg("could not truncate file \"%s\": %m",
1193 : FilePathName(v->mdfd_vfd))));
1194 :
1195 0 : if (!SmgrIsTemp(reln))
1196 0 : register_dirty_segment(reln, forknum, v);
1197 :
1198 : /* we never drop the 1st segment */
1199 : Assert(v != &reln->md_seg_fds[forknum][0]);
1200 :
1201 0 : FileClose(v->mdfd_vfd);
1202 0 : _fdvec_resize(reln, forknum, curopensegs - 1);
1203 : }
1204 890 : else if (priorblocks + ((BlockNumber) RELSEG_SIZE) > nblocks)
1205 : {
1206 : /*
1207 : * This is the last segment we want to keep. Truncate the file to
1208 : * the right length. NOTE: if nblocks is exactly a multiple K of
1209 : * RELSEG_SIZE, we will truncate the K+1st segment to 0 length but
1210 : * keep it. This adheres to the invariant given in the header
1211 : * comments.
1212 : */
1213 890 : BlockNumber lastsegblocks = nblocks - priorblocks;
1214 :
1215 890 : if (FileTruncate(v->mdfd_vfd, (off_t) lastsegblocks * BLCKSZ, WAIT_EVENT_DATA_FILE_TRUNCATE) < 0)
1216 0 : ereport(ERROR,
1217 : (errcode_for_file_access(),
1218 : errmsg("could not truncate file \"%s\" to %u blocks: %m",
1219 : FilePathName(v->mdfd_vfd),
1220 : nblocks)));
1221 890 : if (!SmgrIsTemp(reln))
1222 616 : register_dirty_segment(reln, forknum, v);
1223 : }
1224 : else
1225 : {
1226 : /*
1227 : * We still need this segment, so nothing to do for this and any
1228 : * earlier segment.
1229 : */
1230 0 : break;
1231 : }
1232 890 : curopensegs--;
1233 : }
1234 : }
1235 :
1236 : /*
1237 : * mdregistersync() -- Mark whole relation as needing fsync
1238 : */
1239 : void
1240 44712 : mdregistersync(SMgrRelation reln, ForkNumber forknum)
1241 : {
1242 : int segno;
1243 : int min_inactive_seg;
1244 :
1245 : /*
1246 : * NOTE: mdnblocks makes sure we have opened all active segments, so that
1247 : * the loop below will get them all!
1248 : */
1249 44712 : mdnblocks(reln, forknum);
1250 :
1251 44712 : min_inactive_seg = segno = reln->md_num_open_segs[forknum];
1252 :
1253 : /*
1254 : * Temporarily open inactive segments, then close them after sync. There
1255 : * may be some inactive segments left opened after error, but that is
1256 : * harmless. We don't bother to clean them up and take a risk of further
1257 : * trouble. The next mdclose() will soon close them.
1258 : */
1259 44712 : while (_mdfd_openseg(reln, forknum, segno, 0) != NULL)
1260 0 : segno++;
1261 :
1262 89424 : while (segno > 0)
1263 : {
1264 44712 : MdfdVec *v = &reln->md_seg_fds[forknum][segno - 1];
1265 :
1266 44712 : register_dirty_segment(reln, forknum, v);
1267 :
1268 : /* Close inactive segments immediately */
1269 44712 : if (segno > min_inactive_seg)
1270 : {
1271 0 : FileClose(v->mdfd_vfd);
1272 0 : _fdvec_resize(reln, forknum, segno - 1);
1273 : }
1274 :
1275 44712 : segno--;
1276 : }
1277 44712 : }
1278 :
1279 : /*
1280 : * mdimmedsync() -- Immediately sync a relation to stable storage.
1281 : *
1282 : * Note that only writes already issued are synced; this routine knows
1283 : * nothing of dirty buffers that may exist inside the buffer manager. We
1284 : * sync active and inactive segments; smgrDoPendingSyncs() relies on this.
1285 : * Consider a relation skipping WAL. Suppose a checkpoint syncs blocks of
1286 : * some segment, then mdtruncate() renders that segment inactive. If we
1287 : * crash before the next checkpoint syncs the newly-inactive segment, that
1288 : * segment may survive recovery, reintroducing unwanted data into the table.
1289 : */
1290 : void
1291 20 : mdimmedsync(SMgrRelation reln, ForkNumber forknum)
1292 : {
1293 : int segno;
1294 : int min_inactive_seg;
1295 :
1296 : /*
1297 : * NOTE: mdnblocks makes sure we have opened all active segments, so that
1298 : * the loop below will get them all!
1299 : */
1300 20 : mdnblocks(reln, forknum);
1301 :
1302 20 : min_inactive_seg = segno = reln->md_num_open_segs[forknum];
1303 :
1304 : /*
1305 : * Temporarily open inactive segments, then close them after sync. There
1306 : * may be some inactive segments left opened after fsync() error, but that
1307 : * is harmless. We don't bother to clean them up and take a risk of
1308 : * further trouble. The next mdclose() will soon close them.
1309 : */
1310 20 : while (_mdfd_openseg(reln, forknum, segno, 0) != NULL)
1311 0 : segno++;
1312 :
1313 40 : while (segno > 0)
1314 : {
1315 20 : MdfdVec *v = &reln->md_seg_fds[forknum][segno - 1];
1316 :
1317 : /*
1318 : * fsyncs done through mdimmedsync() should be tracked in a separate
1319 : * IOContext than those done through mdsyncfiletag() to differentiate
1320 : * between unavoidable client backend fsyncs (e.g. those done during
1321 : * index build) and those which ideally would have been done by the
1322 : * checkpointer. Since other IO operations bypassing the buffer
1323 : * manager could also be tracked in such an IOContext, wait until
1324 : * these are also tracked to track immediate fsyncs.
1325 : */
1326 20 : if (FileSync(v->mdfd_vfd, WAIT_EVENT_DATA_FILE_IMMEDIATE_SYNC) < 0)
1327 0 : ereport(data_sync_elevel(ERROR),
1328 : (errcode_for_file_access(),
1329 : errmsg("could not fsync file \"%s\": %m",
1330 : FilePathName(v->mdfd_vfd))));
1331 :
1332 : /* Close inactive segments immediately */
1333 20 : if (segno > min_inactive_seg)
1334 : {
1335 0 : FileClose(v->mdfd_vfd);
1336 0 : _fdvec_resize(reln, forknum, segno - 1);
1337 : }
1338 :
1339 20 : segno--;
1340 : }
1341 20 : }
1342 :
1343 : /*
1344 : * register_dirty_segment() -- Mark a relation segment as needing fsync
1345 : *
1346 : * If there is a local pending-ops table, just make an entry in it for
1347 : * ProcessSyncRequests to process later. Otherwise, try to pass off the
1348 : * fsync request to the checkpointer process. If that fails, just do the
1349 : * fsync locally before returning (we hope this will not happen often
1350 : * enough to be a performance problem).
1351 : */
1352 : static void
1353 1569842 : register_dirty_segment(SMgrRelation reln, ForkNumber forknum, MdfdVec *seg)
1354 : {
1355 : FileTag tag;
1356 :
1357 1569842 : INIT_MD_FILETAG(tag, reln->smgr_rlocator.locator, forknum, seg->mdfd_segno);
1358 :
1359 : /* Temp relations should never be fsync'd */
1360 : Assert(!SmgrIsTemp(reln));
1361 :
1362 1569842 : if (!RegisterSyncRequest(&tag, SYNC_REQUEST, false /* retryOnError */ ))
1363 : {
1364 : instr_time io_start;
1365 :
1366 54 : ereport(DEBUG1,
1367 : (errmsg_internal("could not forward fsync request because request queue is full")));
1368 :
1369 54 : io_start = pgstat_prepare_io_time(track_io_timing);
1370 :
1371 54 : if (FileSync(seg->mdfd_vfd, WAIT_EVENT_DATA_FILE_SYNC) < 0)
1372 0 : ereport(data_sync_elevel(ERROR),
1373 : (errcode_for_file_access(),
1374 : errmsg("could not fsync file \"%s\": %m",
1375 : FilePathName(seg->mdfd_vfd))));
1376 :
1377 : /*
1378 : * We have no way of knowing if the current IOContext is
1379 : * IOCONTEXT_NORMAL or IOCONTEXT_[BULKREAD, BULKWRITE, VACUUM] at this
1380 : * point, so count the fsync as being in the IOCONTEXT_NORMAL
1381 : * IOContext. This is probably okay, because the number of backend
1382 : * fsyncs doesn't say anything about the efficacy of the
1383 : * BufferAccessStrategy. And counting both fsyncs done in
1384 : * IOCONTEXT_NORMAL and IOCONTEXT_[BULKREAD, BULKWRITE, VACUUM] under
1385 : * IOCONTEXT_NORMAL is likely clearer when investigating the number of
1386 : * backend fsyncs.
1387 : */
1388 54 : pgstat_count_io_op_time(IOOBJECT_RELATION, IOCONTEXT_NORMAL,
1389 : IOOP_FSYNC, io_start, 1);
1390 : }
1391 1569842 : }
1392 :
1393 : /*
1394 : * register_unlink_segment() -- Schedule a file to be deleted after next checkpoint
1395 : */
1396 : static void
1397 65846 : register_unlink_segment(RelFileLocatorBackend rlocator, ForkNumber forknum,
1398 : BlockNumber segno)
1399 : {
1400 : FileTag tag;
1401 :
1402 65846 : INIT_MD_FILETAG(tag, rlocator.locator, forknum, segno);
1403 :
1404 : /* Should never be used with temp relations */
1405 : Assert(!RelFileLocatorBackendIsTemp(rlocator));
1406 :
1407 65846 : RegisterSyncRequest(&tag, SYNC_UNLINK_REQUEST, true /* retryOnError */ );
1408 65846 : }
1409 :
1410 : /*
1411 : * register_forget_request() -- forget any fsyncs for a relation fork's segment
1412 : */
1413 : static void
1414 253962 : register_forget_request(RelFileLocatorBackend rlocator, ForkNumber forknum,
1415 : BlockNumber segno)
1416 : {
1417 : FileTag tag;
1418 :
1419 253962 : INIT_MD_FILETAG(tag, rlocator.locator, forknum, segno);
1420 :
1421 253962 : RegisterSyncRequest(&tag, SYNC_FORGET_REQUEST, true /* retryOnError */ );
1422 253962 : }
1423 :
1424 : /*
1425 : * ForgetDatabaseSyncRequests -- forget any fsyncs and unlinks for a DB
1426 : */
1427 : void
1428 84 : ForgetDatabaseSyncRequests(Oid dbid)
1429 : {
1430 : FileTag tag;
1431 : RelFileLocator rlocator;
1432 :
1433 84 : rlocator.dbOid = dbid;
1434 84 : rlocator.spcOid = 0;
1435 84 : rlocator.relNumber = 0;
1436 :
1437 84 : INIT_MD_FILETAG(tag, rlocator, InvalidForkNumber, InvalidBlockNumber);
1438 :
1439 84 : RegisterSyncRequest(&tag, SYNC_FILTER_REQUEST, true /* retryOnError */ );
1440 84 : }
1441 :
1442 : /*
1443 : * DropRelationFiles -- drop files of all given relations
1444 : */
1445 : void
1446 4964 : DropRelationFiles(RelFileLocator *delrels, int ndelrels, bool isRedo)
1447 : {
1448 : SMgrRelation *srels;
1449 : int i;
1450 :
1451 4964 : srels = palloc(sizeof(SMgrRelation) * ndelrels);
1452 19078 : for (i = 0; i < ndelrels; i++)
1453 : {
1454 14114 : SMgrRelation srel = smgropen(delrels[i], INVALID_PROC_NUMBER);
1455 :
1456 14114 : if (isRedo)
1457 : {
1458 : ForkNumber fork;
1459 :
1460 70330 : for (fork = 0; fork <= MAX_FORKNUM; fork++)
1461 56264 : XLogDropRelation(delrels[i], fork);
1462 : }
1463 14114 : srels[i] = srel;
1464 : }
1465 :
1466 4964 : smgrdounlinkall(srels, ndelrels, isRedo);
1467 :
1468 19078 : for (i = 0; i < ndelrels; i++)
1469 14114 : smgrclose(srels[i]);
1470 4964 : pfree(srels);
1471 4964 : }
1472 :
1473 :
1474 : /*
1475 : * _fdvec_resize() -- Resize the fork's open segments array
1476 : */
1477 : static void
1478 2259552 : _fdvec_resize(SMgrRelation reln,
1479 : ForkNumber forknum,
1480 : int nseg)
1481 : {
1482 2259552 : if (nseg == 0)
1483 : {
1484 864664 : if (reln->md_num_open_segs[forknum] > 0)
1485 : {
1486 864664 : pfree(reln->md_seg_fds[forknum]);
1487 864664 : reln->md_seg_fds[forknum] = NULL;
1488 : }
1489 : }
1490 1394888 : else if (reln->md_num_open_segs[forknum] == 0)
1491 : {
1492 1394888 : reln->md_seg_fds[forknum] =
1493 1394888 : MemoryContextAlloc(MdCxt, sizeof(MdfdVec) * nseg);
1494 : }
1495 : else
1496 : {
1497 : /*
1498 : * It doesn't seem worthwhile complicating the code to amortize
1499 : * repalloc() calls. Those are far faster than PathNameOpenFile() or
1500 : * FileClose(), and the memory context internally will sometimes avoid
1501 : * doing an actual reallocation.
1502 : */
1503 0 : reln->md_seg_fds[forknum] =
1504 0 : repalloc(reln->md_seg_fds[forknum],
1505 : sizeof(MdfdVec) * nseg);
1506 : }
1507 :
1508 2259552 : reln->md_num_open_segs[forknum] = nseg;
1509 2259552 : }
1510 :
1511 : /*
1512 : * Return the filename for the specified segment of the relation. The
1513 : * returned string is palloc'd.
1514 : */
1515 : static char *
1516 44756 : _mdfd_segpath(SMgrRelation reln, ForkNumber forknum, BlockNumber segno)
1517 : {
1518 : char *path,
1519 : *fullpath;
1520 :
1521 44756 : path = relpath(reln->smgr_rlocator, forknum);
1522 :
1523 44756 : if (segno > 0)
1524 : {
1525 44756 : fullpath = psprintf("%s.%u", path, segno);
1526 44756 : pfree(path);
1527 : }
1528 : else
1529 0 : fullpath = path;
1530 :
1531 44756 : return fullpath;
1532 : }
1533 :
1534 : /*
1535 : * Open the specified segment of the relation,
1536 : * and make a MdfdVec object for it. Returns NULL on failure.
1537 : */
1538 : static MdfdVec *
1539 44732 : _mdfd_openseg(SMgrRelation reln, ForkNumber forknum, BlockNumber segno,
1540 : int oflags)
1541 : {
1542 : MdfdVec *v;
1543 : File fd;
1544 : char *fullpath;
1545 :
1546 44732 : fullpath = _mdfd_segpath(reln, forknum, segno);
1547 :
1548 : /* open the file */
1549 44732 : fd = PathNameOpenFile(fullpath, _mdfd_open_flags() | oflags);
1550 :
1551 44732 : pfree(fullpath);
1552 :
1553 44732 : if (fd < 0)
1554 44732 : return NULL;
1555 :
1556 : /*
1557 : * Segments are always opened in order from lowest to highest, so we must
1558 : * be adding a new one at the end.
1559 : */
1560 : Assert(segno == reln->md_num_open_segs[forknum]);
1561 :
1562 0 : _fdvec_resize(reln, forknum, segno + 1);
1563 :
1564 : /* fill the entry */
1565 0 : v = &reln->md_seg_fds[forknum][segno];
1566 0 : v->mdfd_vfd = fd;
1567 0 : v->mdfd_segno = segno;
1568 :
1569 : Assert(_mdnblocks(reln, forknum, v) <= ((BlockNumber) RELSEG_SIZE));
1570 :
1571 : /* all done */
1572 0 : return v;
1573 : }
1574 :
1575 : /*
1576 : * _mdfd_getseg() -- Find the segment of the relation holding the
1577 : * specified block.
1578 : *
1579 : * If the segment doesn't exist, we ereport, return NULL, or create the
1580 : * segment, according to "behavior". Note: skipFsync is only used in the
1581 : * EXTENSION_CREATE case.
1582 : */
1583 : static MdfdVec *
1584 3980278 : _mdfd_getseg(SMgrRelation reln, ForkNumber forknum, BlockNumber blkno,
1585 : bool skipFsync, int behavior)
1586 : {
1587 : MdfdVec *v;
1588 : BlockNumber targetseg;
1589 : BlockNumber nextsegno;
1590 :
1591 : /* some way to handle non-existent segments needs to be specified */
1592 : Assert(behavior &
1593 : (EXTENSION_FAIL | EXTENSION_CREATE | EXTENSION_RETURN_NULL |
1594 : EXTENSION_DONT_OPEN));
1595 :
1596 3980278 : targetseg = blkno / ((BlockNumber) RELSEG_SIZE);
1597 :
1598 : /* if an existing and opened segment, we're done */
1599 3980278 : if (targetseg < reln->md_num_open_segs[forknum])
1600 : {
1601 3637144 : v = &reln->md_seg_fds[forknum][targetseg];
1602 3637144 : return v;
1603 : }
1604 :
1605 : /* The caller only wants the segment if we already had it open. */
1606 343134 : if (behavior & EXTENSION_DONT_OPEN)
1607 860 : return NULL;
1608 :
1609 : /*
1610 : * The target segment is not yet open. Iterate over all the segments
1611 : * between the last opened and the target segment. This way missing
1612 : * segments either raise an error, or get created (according to
1613 : * 'behavior'). Start with either the last opened, or the first segment if
1614 : * none was opened before.
1615 : */
1616 342274 : if (reln->md_num_open_segs[forknum] > 0)
1617 24 : v = &reln->md_seg_fds[forknum][reln->md_num_open_segs[forknum] - 1];
1618 : else
1619 : {
1620 342250 : v = mdopenfork(reln, forknum, behavior);
1621 342244 : if (!v)
1622 0 : return NULL; /* if behavior & EXTENSION_RETURN_NULL */
1623 : }
1624 :
1625 342268 : for (nextsegno = reln->md_num_open_segs[forknum];
1626 0 : nextsegno <= targetseg; nextsegno++)
1627 : {
1628 24 : BlockNumber nblocks = _mdnblocks(reln, forknum, v);
1629 24 : int flags = 0;
1630 :
1631 : Assert(nextsegno == v->mdfd_segno + 1);
1632 :
1633 24 : if (nblocks > ((BlockNumber) RELSEG_SIZE))
1634 0 : elog(FATAL, "segment too big");
1635 :
1636 24 : if ((behavior & EXTENSION_CREATE) ||
1637 24 : (InRecovery && (behavior & EXTENSION_CREATE_RECOVERY)))
1638 : {
1639 : /*
1640 : * Normally we will create new segments only if authorized by the
1641 : * caller (i.e., we are doing mdextend()). But when doing WAL
1642 : * recovery, create segments anyway; this allows cases such as
1643 : * replaying WAL data that has a write into a high-numbered
1644 : * segment of a relation that was later deleted. We want to go
1645 : * ahead and create the segments so we can finish out the replay.
1646 : *
1647 : * We have to maintain the invariant that segments before the last
1648 : * active segment are of size RELSEG_SIZE; therefore, if
1649 : * extending, pad them out with zeroes if needed. (This only
1650 : * matters if in recovery, or if the caller is extending the
1651 : * relation discontiguously, but that can happen in hash indexes.)
1652 : */
1653 0 : if (nblocks < ((BlockNumber) RELSEG_SIZE))
1654 : {
1655 0 : char *zerobuf = palloc_aligned(BLCKSZ, PG_IO_ALIGN_SIZE,
1656 : MCXT_ALLOC_ZERO);
1657 :
1658 0 : mdextend(reln, forknum,
1659 0 : nextsegno * ((BlockNumber) RELSEG_SIZE) - 1,
1660 : zerobuf, skipFsync);
1661 0 : pfree(zerobuf);
1662 : }
1663 0 : flags = O_CREAT;
1664 : }
1665 24 : else if (!(behavior & EXTENSION_DONT_CHECK_SIZE) &&
1666 : nblocks < ((BlockNumber) RELSEG_SIZE))
1667 : {
1668 : /*
1669 : * When not extending (or explicitly including truncated
1670 : * segments), only open the next segment if the current one is
1671 : * exactly RELSEG_SIZE. If not (this branch), either return NULL
1672 : * or fail.
1673 : */
1674 24 : if (behavior & EXTENSION_RETURN_NULL)
1675 : {
1676 : /*
1677 : * Some callers discern between reasons for _mdfd_getseg()
1678 : * returning NULL based on errno. As there's no failing
1679 : * syscall involved in this case, explicitly set errno to
1680 : * ENOENT, as that seems the closest interpretation.
1681 : */
1682 0 : errno = ENOENT;
1683 0 : return NULL;
1684 : }
1685 :
1686 24 : ereport(ERROR,
1687 : (errcode_for_file_access(),
1688 : errmsg("could not open file \"%s\" (target block %u): previous segment is only %u blocks",
1689 : _mdfd_segpath(reln, forknum, nextsegno),
1690 : blkno, nblocks)));
1691 : }
1692 :
1693 0 : v = _mdfd_openseg(reln, forknum, nextsegno, flags);
1694 :
1695 0 : if (v == NULL)
1696 : {
1697 0 : if ((behavior & EXTENSION_RETURN_NULL) &&
1698 0 : FILE_POSSIBLY_DELETED(errno))
1699 0 : return NULL;
1700 0 : ereport(ERROR,
1701 : (errcode_for_file_access(),
1702 : errmsg("could not open file \"%s\" (target block %u): %m",
1703 : _mdfd_segpath(reln, forknum, nextsegno),
1704 : blkno)));
1705 : }
1706 : }
1707 :
1708 342244 : return v;
1709 : }
1710 :
1711 : /*
1712 : * Get number of blocks present in a single disk file
1713 : */
1714 : static BlockNumber
1715 3566492 : _mdnblocks(SMgrRelation reln, ForkNumber forknum, MdfdVec *seg)
1716 : {
1717 : off_t len;
1718 :
1719 3566492 : len = FileSize(seg->mdfd_vfd);
1720 3566492 : if (len < 0)
1721 0 : ereport(ERROR,
1722 : (errcode_for_file_access(),
1723 : errmsg("could not seek to end of file \"%s\": %m",
1724 : FilePathName(seg->mdfd_vfd))));
1725 : /* note that this calculation will ignore any partial block at EOF */
1726 3566492 : return (BlockNumber) (len / BLCKSZ);
1727 : }
1728 :
1729 : /*
1730 : * Sync a file to disk, given a file tag. Write the path into an output
1731 : * buffer so the caller can use it in error messages.
1732 : *
1733 : * Return 0 on success, -1 on failure, with errno set.
1734 : */
1735 : int
1736 0 : mdsyncfiletag(const FileTag *ftag, char *path)
1737 : {
1738 0 : SMgrRelation reln = smgropen(ftag->rlocator, INVALID_PROC_NUMBER);
1739 : File file;
1740 : instr_time io_start;
1741 : bool need_to_close;
1742 : int result,
1743 : save_errno;
1744 :
1745 : /* See if we already have the file open, or need to open it. */
1746 0 : if (ftag->segno < reln->md_num_open_segs[ftag->forknum])
1747 : {
1748 0 : file = reln->md_seg_fds[ftag->forknum][ftag->segno].mdfd_vfd;
1749 0 : strlcpy(path, FilePathName(file), MAXPGPATH);
1750 0 : need_to_close = false;
1751 : }
1752 : else
1753 : {
1754 : char *p;
1755 :
1756 0 : p = _mdfd_segpath(reln, ftag->forknum, ftag->segno);
1757 0 : strlcpy(path, p, MAXPGPATH);
1758 0 : pfree(p);
1759 :
1760 0 : file = PathNameOpenFile(path, _mdfd_open_flags());
1761 0 : if (file < 0)
1762 0 : return -1;
1763 0 : need_to_close = true;
1764 : }
1765 :
1766 0 : io_start = pgstat_prepare_io_time(track_io_timing);
1767 :
1768 : /* Sync the file. */
1769 0 : result = FileSync(file, WAIT_EVENT_DATA_FILE_SYNC);
1770 0 : save_errno = errno;
1771 :
1772 0 : if (need_to_close)
1773 0 : FileClose(file);
1774 :
1775 0 : pgstat_count_io_op_time(IOOBJECT_RELATION, IOCONTEXT_NORMAL,
1776 : IOOP_FSYNC, io_start, 1);
1777 :
1778 0 : errno = save_errno;
1779 0 : return result;
1780 : }
1781 :
1782 : /*
1783 : * Unlink a file, given a file tag. Write the path into an output
1784 : * buffer so the caller can use it in error messages.
1785 : *
1786 : * Return 0 on success, -1 on failure, with errno set.
1787 : */
1788 : int
1789 61720 : mdunlinkfiletag(const FileTag *ftag, char *path)
1790 : {
1791 : char *p;
1792 :
1793 : /* Compute the path. */
1794 61720 : p = relpathperm(ftag->rlocator, MAIN_FORKNUM);
1795 61720 : strlcpy(path, p, MAXPGPATH);
1796 61720 : pfree(p);
1797 :
1798 : /* Try to unlink the file. */
1799 61720 : return unlink(path);
1800 : }
1801 :
1802 : /*
1803 : * Check if a given candidate request matches a given tag, when processing
1804 : * a SYNC_FILTER_REQUEST request. This will be called for all pending
1805 : * requests to find out whether to forget them.
1806 : */
1807 : bool
1808 13526 : mdfiletagmatches(const FileTag *ftag, const FileTag *candidate)
1809 : {
1810 : /*
1811 : * For now we only use filter requests as a way to drop all scheduled
1812 : * callbacks relating to a given database, when dropping the database.
1813 : * We'll return true for all candidates that have the same database OID as
1814 : * the ftag from the SYNC_FILTER_REQUEST request, so they're forgotten.
1815 : */
1816 13526 : return ftag->rlocator.dbOid == candidate->rlocator.dbOid;
1817 : }
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