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 2340810 : _mdfd_open_flags(void)
145 : {
146 2340810 : int flags = O_RDWR | PG_BINARY;
147 :
148 2340810 : if (io_direct_flags & IO_DIRECT_DATA)
149 656 : flags |= PG_O_DIRECT;
150 :
151 2340810 : return flags;
152 : }
153 :
154 : /*
155 : * mdinit() -- Initialize private state for magnetic disk storage manager.
156 : */
157 : void
158 35570 : mdinit(void)
159 : {
160 35570 : MdCxt = AllocSetContextCreate(TopMemoryContext,
161 : "MdSmgr",
162 : ALLOCSET_DEFAULT_SIZES);
163 35570 : }
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 999194 : 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 999194 : if (!InRecovery)
179 958490 : mdclose(reln, forknum);
180 :
181 999194 : 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 10884428 : mdcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo)
191 : {
192 : MdfdVec *mdfd;
193 : char *path;
194 : File fd;
195 :
196 10884428 : if (isRedo && reln->md_num_open_segs[forknum] > 0)
197 10593634 : 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 290794 : TablespaceCreateDbspace(reln->smgr_rlocator.locator.spcOid,
211 : reln->smgr_rlocator.locator.dbOid,
212 : isRedo);
213 :
214 290794 : path = relpath(reln->smgr_rlocator, forknum);
215 :
216 290794 : fd = PathNameOpenFile(path, _mdfd_open_flags() | O_CREAT | O_EXCL);
217 :
218 290794 : if (fd < 0)
219 : {
220 8936 : int save_errno = errno;
221 :
222 8936 : if (isRedo)
223 8936 : fd = PathNameOpenFile(path, _mdfd_open_flags());
224 8936 : 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 290794 : pfree(path);
235 :
236 290794 : _fdvec_resize(reln, forknum, 1);
237 290794 : mdfd = &reln->md_seg_fds[forknum][0];
238 290794 : mdfd->mdfd_vfd = fd;
239 290794 : mdfd->mdfd_segno = 0;
240 :
241 290794 : if (!SmgrIsTemp(reln))
242 284508 : 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 347560 : mdunlink(RelFileLocatorBackend rlocator, ForkNumber forknum, bool isRedo)
308 : {
309 : /* Now do the per-fork work */
310 347560 : if (forknum == InvalidForkNumber)
311 : {
312 0 : for (forknum = 0; forknum <= MAX_FORKNUM; forknum++)
313 0 : mdunlinkfork(rlocator, forknum, isRedo);
314 : }
315 : else
316 347560 : mdunlinkfork(rlocator, forknum, isRedo);
317 347560 : }
318 :
319 : /*
320 : * Truncate a file to release disk space.
321 : */
322 : static int
323 407908 : do_truncate(const char *path)
324 : {
325 : int save_errno;
326 : int ret;
327 :
328 407908 : ret = pg_truncate(path, 0);
329 :
330 : /* Log a warning here to avoid repetition in callers. */
331 407908 : 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 407908 : return ret;
341 : }
342 :
343 : static void
344 347560 : mdunlinkfork(RelFileLocatorBackend rlocator, ForkNumber forknum, bool isRedo)
345 : {
346 : char *path;
347 : int ret;
348 : int save_errno;
349 :
350 347560 : 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 347560 : if (isRedo || IsBinaryUpgrade || forknum != MAIN_FORKNUM ||
357 72478 : RelFileLocatorBackendIsTemp(rlocator))
358 : {
359 281080 : if (!RelFileLocatorBackendIsTemp(rlocator))
360 : {
361 : /* Prevent other backends' fds from holding on to the disk space */
362 257088 : ret = do_truncate(path);
363 :
364 : /* Forget any pending sync requests for the first segment */
365 257088 : save_errno = errno;
366 257088 : register_forget_request(rlocator, forknum, 0 /* first seg */ );
367 257088 : errno = save_errno;
368 : }
369 : else
370 23992 : ret = 0;
371 :
372 : /* Next unlink the file, unless it was already found to be missing */
373 281080 : if (ret >= 0 || errno != ENOENT)
374 : {
375 41860 : ret = unlink(path);
376 41860 : 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 66480 : ret = do_truncate(path);
390 :
391 : /* Register request to unlink first segment later */
392 66480 : save_errno = errno;
393 66480 : register_unlink_segment(rlocator, forknum, 0 /* first seg */ );
394 66480 : 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 347560 : if (ret >= 0 || errno != ENOENT)
410 : {
411 90626 : char *segpath = (char *) palloc(strlen(path) + 12);
412 : BlockNumber segno;
413 :
414 90626 : for (segno = 1;; segno++)
415 : {
416 90626 : sprintf(segpath, "%s.%u", path, segno);
417 :
418 90626 : 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 84340 : if (do_truncate(segpath) < 0 && errno == ENOENT)
425 84340 : 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 6286 : if (unlink(segpath) < 0)
435 : {
436 : /* ENOENT is expected after the last segment... */
437 6286 : if (errno != ENOENT)
438 0 : ereport(WARNING,
439 : (errcode_for_file_access(),
440 : errmsg("could not remove file \"%s\": %m", segpath)));
441 6286 : break;
442 : }
443 : }
444 90626 : pfree(segpath);
445 : }
446 :
447 347560 : pfree(path);
448 347560 : }
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 217812 : 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 217812 : 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 217812 : v = _mdfd_getseg(reln, forknum, blocknum, skipFsync, EXTENSION_CREATE);
490 :
491 217812 : seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
492 :
493 : Assert(seekpos < (off_t) BLCKSZ * RELSEG_SIZE);
494 :
495 217812 : 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 217812 : if (!skipFsync && !SmgrIsTemp(reln))
513 56 : register_dirty_segment(reln, forknum, v);
514 :
515 : Assert(_mdnblocks(reln, forknum, v) <= ((BlockNumber) RELSEG_SIZE));
516 217812 : }
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 390122 : mdzeroextend(SMgrRelation reln, ForkNumber forknum,
526 : BlockNumber blocknum, int nblocks, bool skipFsync)
527 : {
528 : MdfdVec *v;
529 390122 : BlockNumber curblocknum = blocknum;
530 390122 : 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 390122 : 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 780244 : while (remblocks > 0)
552 : {
553 390122 : BlockNumber segstartblock = curblocknum % ((BlockNumber) RELSEG_SIZE);
554 390122 : off_t seekpos = (off_t) BLCKSZ * segstartblock;
555 : int numblocks;
556 :
557 390122 : if (segstartblock + remblocks > RELSEG_SIZE)
558 0 : numblocks = RELSEG_SIZE - segstartblock;
559 : else
560 390122 : numblocks = remblocks;
561 :
562 390122 : 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 390122 : if (numblocks > 8)
579 : {
580 : int ret;
581 :
582 988 : ret = FileFallocate(v->mdfd_vfd,
583 : seekpos, (off_t) BLCKSZ * numblocks,
584 : WAIT_EVENT_DATA_FILE_EXTEND);
585 988 : 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 389134 : ret = FileZero(v->mdfd_vfd,
606 : seekpos, (off_t) BLCKSZ * numblocks,
607 : WAIT_EVENT_DATA_FILE_EXTEND);
608 389134 : 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 390122 : if (!skipFsync && !SmgrIsTemp(reln))
617 372458 : register_dirty_segment(reln, forknum, v);
618 :
619 : Assert(_mdnblocks(reln, forknum, v) <= ((BlockNumber) RELSEG_SIZE));
620 :
621 390122 : remblocks -= numblocks;
622 390122 : curblocknum += numblocks;
623 : }
624 390122 : }
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 5225120 : 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 5225120 : if (reln->md_num_open_segs[forknum] > 0)
645 3230160 : return &reln->md_seg_fds[forknum][0];
646 :
647 1994960 : path = relpath(reln->smgr_rlocator, forknum);
648 :
649 1994960 : fd = PathNameOpenFile(path, _mdfd_open_flags());
650 :
651 1994960 : if (fd < 0)
652 : {
653 679056 : if ((behavior & EXTENSION_RETURN_NULL) &&
654 679012 : FILE_POSSIBLY_DELETED(errno))
655 : {
656 679012 : pfree(path);
657 679012 : return NULL;
658 : }
659 44 : ereport(ERROR,
660 : (errcode_for_file_access(),
661 : errmsg("could not open file \"%s\": %m", path)));
662 : }
663 :
664 1315904 : pfree(path);
665 :
666 1315904 : _fdvec_resize(reln, forknum, 1);
667 1315904 : mdfd = &reln->md_seg_fds[forknum][0];
668 1315904 : mdfd->mdfd_vfd = fd;
669 1315904 : mdfd->mdfd_segno = 0;
670 :
671 : Assert(_mdnblocks(reln, forknum, mdfd) <= ((BlockNumber) RELSEG_SIZE));
672 :
673 1315904 : return mdfd;
674 : }
675 :
676 : /*
677 : * mdopen() -- Initialize newly-opened relation.
678 : */
679 : void
680 1937082 : mdopen(SMgrRelation reln)
681 : {
682 : /* mark it not open */
683 9685410 : for (int forknum = 0; forknum <= MAX_FORKNUM; forknum++)
684 7748328 : reln->md_num_open_segs[forknum] = 0;
685 1937082 : }
686 :
687 : /*
688 : * mdclose() -- Close the specified relation, if it isn't closed already.
689 : */
690 : void
691 6520042 : mdclose(SMgrRelation reln, ForkNumber forknum)
692 : {
693 6520042 : int nopensegs = reln->md_num_open_segs[forknum];
694 :
695 : /* No work if already closed */
696 6520042 : if (nopensegs == 0)
697 5559306 : return;
698 :
699 : /* close segments starting from the end */
700 1921472 : while (nopensegs > 0)
701 : {
702 960736 : MdfdVec *v = &reln->md_seg_fds[forknum][nopensegs - 1];
703 :
704 960736 : FileClose(v->mdfd_vfd);
705 960736 : _fdvec_resize(reln, forknum, nopensegs - 1);
706 960736 : nopensegs--;
707 : }
708 : }
709 :
710 : /*
711 : * mdprefetch() -- Initiate asynchronous read of the specified blocks of a relation
712 : */
713 : bool
714 174112 : 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 174112 : if ((uint64) blocknum + nblocks > (uint64) MaxBlockNumber + 1)
722 0 : return false;
723 :
724 348224 : while (nblocks > 0)
725 : {
726 : off_t seekpos;
727 : MdfdVec *v;
728 : int nblocks_this_segment;
729 :
730 174112 : v = _mdfd_getseg(reln, forknum, blocknum, false,
731 174112 : InRecovery ? EXTENSION_RETURN_NULL : EXTENSION_FAIL);
732 174112 : if (v == NULL)
733 0 : return false;
734 :
735 174112 : seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
736 :
737 : Assert(seekpos < (off_t) BLCKSZ * RELSEG_SIZE);
738 :
739 174112 : nblocks_this_segment =
740 174112 : Min(nblocks,
741 : RELSEG_SIZE - (blocknum % ((BlockNumber) RELSEG_SIZE)));
742 :
743 174112 : (void) FilePrefetch(v->mdfd_vfd, seekpos, BLCKSZ * nblocks_this_segment,
744 : WAIT_EVENT_DATA_FILE_PREFETCH);
745 :
746 174112 : blocknum += nblocks_this_segment;
747 174112 : nblocks -= nblocks_this_segment;
748 : }
749 : #endif /* USE_PREFETCH */
750 :
751 174112 : 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 3037982 : 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 6314534 : 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 3037982 : iovp = &iov[0];
779 3037982 : iovp->iov_base = buffers[0];
780 3037982 : iovp->iov_len = BLCKSZ;
781 3037982 : iovcnt = 1;
782 :
783 : /* Try to merge the rest. */
784 3276552 : for (int i = 1; i < nblocks; ++i)
785 : {
786 238570 : void *buffer = buffers[i];
787 :
788 238570 : if (((char *) iovp->iov_base + iovp->iov_len) == buffer)
789 : {
790 : /* Contiguous with the last iovec. */
791 233194 : iovp->iov_len += BLCKSZ;
792 : }
793 : else
794 : {
795 : /* Need a new iovec. */
796 5376 : iovp++;
797 5376 : iovp->iov_base = buffer;
798 5376 : iovp->iov_len = BLCKSZ;
799 5376 : iovcnt++;
800 : }
801 : }
802 :
803 3037982 : return iovcnt;
804 : }
805 :
806 : /*
807 : * mdmaxcombine() -- Return the maximum number of total blocks that can be
808 : * combined with an IO starting at blocknum.
809 : */
810 : uint32
811 51568 : mdmaxcombine(SMgrRelation reln, ForkNumber forknum,
812 : BlockNumber blocknum)
813 : {
814 : BlockNumber segoff;
815 :
816 51568 : segoff = blocknum % ((BlockNumber) RELSEG_SIZE);
817 :
818 51568 : return RELSEG_SIZE - segoff;
819 : }
820 :
821 : /*
822 : * mdreadv() -- Read the specified blocks from a relation.
823 : */
824 : void
825 2093346 : mdreadv(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
826 : void **buffers, BlockNumber nblocks)
827 : {
828 4186662 : while (nblocks > 0)
829 : {
830 : struct iovec iov[PG_IOV_MAX];
831 : int iovcnt;
832 : off_t seekpos;
833 : int nbytes;
834 : MdfdVec *v;
835 : BlockNumber nblocks_this_segment;
836 : size_t transferred_this_segment;
837 : size_t size_this_segment;
838 :
839 2093346 : v = _mdfd_getseg(reln, forknum, blocknum, false,
840 : EXTENSION_FAIL | EXTENSION_CREATE_RECOVERY);
841 :
842 2093316 : seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
843 :
844 : Assert(seekpos < (off_t) BLCKSZ * RELSEG_SIZE);
845 :
846 2093316 : nblocks_this_segment =
847 2093316 : Min(nblocks,
848 : RELSEG_SIZE - (blocknum % ((BlockNumber) RELSEG_SIZE)));
849 2093316 : nblocks_this_segment = Min(nblocks_this_segment, lengthof(iov));
850 :
851 2093316 : if (nblocks_this_segment != nblocks)
852 0 : elog(ERROR, "read crosses segment boundary");
853 :
854 2093316 : iovcnt = buffers_to_iovec(iov, buffers, nblocks_this_segment);
855 2093316 : size_this_segment = nblocks_this_segment * BLCKSZ;
856 2093316 : transferred_this_segment = 0;
857 :
858 : /*
859 : * Inner loop to continue after a short read. We'll keep going until
860 : * we hit EOF rather than assuming that a short read means we hit the
861 : * end.
862 : */
863 : for (;;)
864 : {
865 : TRACE_POSTGRESQL_SMGR_MD_READ_START(forknum, blocknum,
866 : reln->smgr_rlocator.locator.spcOid,
867 : reln->smgr_rlocator.locator.dbOid,
868 : reln->smgr_rlocator.locator.relNumber,
869 : reln->smgr_rlocator.backend);
870 2093316 : nbytes = FileReadV(v->mdfd_vfd, iov, iovcnt, seekpos,
871 : WAIT_EVENT_DATA_FILE_READ);
872 : TRACE_POSTGRESQL_SMGR_MD_READ_DONE(forknum, blocknum,
873 : reln->smgr_rlocator.locator.spcOid,
874 : reln->smgr_rlocator.locator.dbOid,
875 : reln->smgr_rlocator.locator.relNumber,
876 : reln->smgr_rlocator.backend,
877 : nbytes,
878 : size_this_segment - transferred_this_segment);
879 :
880 : #ifdef SIMULATE_SHORT_READ
881 : nbytes = Min(nbytes, 4096);
882 : #endif
883 :
884 2093316 : if (nbytes < 0)
885 0 : ereport(ERROR,
886 : (errcode_for_file_access(),
887 : errmsg("could not read blocks %u..%u in file \"%s\": %m",
888 : blocknum,
889 : blocknum + nblocks_this_segment - 1,
890 : FilePathName(v->mdfd_vfd))));
891 :
892 2093316 : if (nbytes == 0)
893 : {
894 : /*
895 : * We are at or past EOF, or we read a partial block at EOF.
896 : * Normally this is an error; upper levels should never try to
897 : * read a nonexistent block. However, if zero_damaged_pages
898 : * is ON or we are InRecovery, we should instead return zeroes
899 : * without complaining. This allows, for example, the case of
900 : * trying to update a block that was later truncated away.
901 : */
902 0 : if (zero_damaged_pages || InRecovery)
903 : {
904 0 : for (BlockNumber i = transferred_this_segment / BLCKSZ;
905 : i < nblocks_this_segment;
906 0 : ++i)
907 0 : memset(buffers[i], 0, BLCKSZ);
908 0 : break;
909 : }
910 : else
911 0 : ereport(ERROR,
912 : (errcode(ERRCODE_DATA_CORRUPTED),
913 : errmsg("could not read blocks %u..%u in file \"%s\": read only %zu of %zu bytes",
914 : blocknum,
915 : blocknum + nblocks_this_segment - 1,
916 : FilePathName(v->mdfd_vfd),
917 : transferred_this_segment,
918 : size_this_segment)));
919 : }
920 :
921 : /* One loop should usually be enough. */
922 2093316 : transferred_this_segment += nbytes;
923 : Assert(transferred_this_segment <= size_this_segment);
924 2093316 : if (transferred_this_segment == size_this_segment)
925 2093316 : break;
926 :
927 : /* Adjust position and vectors after a short read. */
928 0 : seekpos += nbytes;
929 0 : iovcnt = compute_remaining_iovec(iov, iov, iovcnt, nbytes);
930 : }
931 :
932 2093316 : nblocks -= nblocks_this_segment;
933 2093316 : buffers += nblocks_this_segment;
934 2093316 : blocknum += nblocks_this_segment;
935 : }
936 2093316 : }
937 :
938 : /*
939 : * mdwritev() -- Write the supplied blocks at the appropriate location.
940 : *
941 : * This is to be used only for updating already-existing blocks of a
942 : * relation (ie, those before the current EOF). To extend a relation,
943 : * use mdextend().
944 : */
945 : void
946 944666 : mdwritev(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
947 : const void **buffers, BlockNumber nblocks, bool skipFsync)
948 : {
949 : /* This assert is too expensive to have on normally ... */
950 : #ifdef CHECK_WRITE_VS_EXTEND
951 : Assert((uint64) blocknum + (uint64) nblocks <= (uint64) mdnblocks(reln, forknum));
952 : #endif
953 :
954 1889332 : while (nblocks > 0)
955 : {
956 : struct iovec iov[PG_IOV_MAX];
957 : int iovcnt;
958 : off_t seekpos;
959 : int nbytes;
960 : MdfdVec *v;
961 : BlockNumber nblocks_this_segment;
962 : size_t transferred_this_segment;
963 : size_t size_this_segment;
964 :
965 944666 : v = _mdfd_getseg(reln, forknum, blocknum, skipFsync,
966 : EXTENSION_FAIL | EXTENSION_CREATE_RECOVERY);
967 :
968 944666 : seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
969 :
970 : Assert(seekpos < (off_t) BLCKSZ * RELSEG_SIZE);
971 :
972 944666 : nblocks_this_segment =
973 944666 : Min(nblocks,
974 : RELSEG_SIZE - (blocknum % ((BlockNumber) RELSEG_SIZE)));
975 944666 : nblocks_this_segment = Min(nblocks_this_segment, lengthof(iov));
976 :
977 944666 : if (nblocks_this_segment != nblocks)
978 0 : elog(ERROR, "write crosses segment boundary");
979 :
980 944666 : iovcnt = buffers_to_iovec(iov, (void **) buffers, nblocks_this_segment);
981 944666 : size_this_segment = nblocks_this_segment * BLCKSZ;
982 944666 : transferred_this_segment = 0;
983 :
984 : /*
985 : * Inner loop to continue after a short write. If the reason is that
986 : * we're out of disk space, a future attempt should get an ENOSPC
987 : * error from the kernel.
988 : */
989 : for (;;)
990 : {
991 : TRACE_POSTGRESQL_SMGR_MD_WRITE_START(forknum, blocknum,
992 : reln->smgr_rlocator.locator.spcOid,
993 : reln->smgr_rlocator.locator.dbOid,
994 : reln->smgr_rlocator.locator.relNumber,
995 : reln->smgr_rlocator.backend);
996 944666 : nbytes = FileWriteV(v->mdfd_vfd, iov, iovcnt, seekpos,
997 : WAIT_EVENT_DATA_FILE_WRITE);
998 : TRACE_POSTGRESQL_SMGR_MD_WRITE_DONE(forknum, blocknum,
999 : reln->smgr_rlocator.locator.spcOid,
1000 : reln->smgr_rlocator.locator.dbOid,
1001 : reln->smgr_rlocator.locator.relNumber,
1002 : reln->smgr_rlocator.backend,
1003 : nbytes,
1004 : size_this_segment - transferred_this_segment);
1005 :
1006 : #ifdef SIMULATE_SHORT_WRITE
1007 : nbytes = Min(nbytes, 4096);
1008 : #endif
1009 :
1010 944666 : if (nbytes < 0)
1011 : {
1012 0 : bool enospc = errno == ENOSPC;
1013 :
1014 0 : ereport(ERROR,
1015 : (errcode_for_file_access(),
1016 : errmsg("could not write blocks %u..%u in file \"%s\": %m",
1017 : blocknum,
1018 : blocknum + nblocks_this_segment - 1,
1019 : FilePathName(v->mdfd_vfd)),
1020 : enospc ? errhint("Check free disk space.") : 0));
1021 : }
1022 :
1023 : /* One loop should usually be enough. */
1024 944666 : transferred_this_segment += nbytes;
1025 : Assert(transferred_this_segment <= size_this_segment);
1026 944666 : if (transferred_this_segment == size_this_segment)
1027 944666 : break;
1028 :
1029 : /* Adjust position and iovecs after a short write. */
1030 0 : seekpos += nbytes;
1031 0 : iovcnt = compute_remaining_iovec(iov, iov, iovcnt, nbytes);
1032 : }
1033 :
1034 944666 : if (!skipFsync && !SmgrIsTemp(reln))
1035 942652 : register_dirty_segment(reln, forknum, v);
1036 :
1037 944666 : nblocks -= nblocks_this_segment;
1038 944666 : buffers += nblocks_this_segment;
1039 944666 : blocknum += nblocks_this_segment;
1040 : }
1041 944666 : }
1042 :
1043 :
1044 : /*
1045 : * mdwriteback() -- Tell the kernel to write pages back to storage.
1046 : *
1047 : * This accepts a range of blocks because flushing several pages at once is
1048 : * considerably more efficient than doing so individually.
1049 : */
1050 : void
1051 0 : mdwriteback(SMgrRelation reln, ForkNumber forknum,
1052 : BlockNumber blocknum, BlockNumber nblocks)
1053 : {
1054 : Assert((io_direct_flags & IO_DIRECT_DATA) == 0);
1055 :
1056 : /*
1057 : * Issue flush requests in as few requests as possible; have to split at
1058 : * segment boundaries though, since those are actually separate files.
1059 : */
1060 0 : while (nblocks > 0)
1061 : {
1062 0 : BlockNumber nflush = nblocks;
1063 : off_t seekpos;
1064 : MdfdVec *v;
1065 : int segnum_start,
1066 : segnum_end;
1067 :
1068 0 : v = _mdfd_getseg(reln, forknum, blocknum, true /* not used */ ,
1069 : EXTENSION_DONT_OPEN);
1070 :
1071 : /*
1072 : * We might be flushing buffers of already removed relations, that's
1073 : * ok, just ignore that case. If the segment file wasn't open already
1074 : * (ie from a recent mdwrite()), then we don't want to re-open it, to
1075 : * avoid a race with PROCSIGNAL_BARRIER_SMGRRELEASE that might leave
1076 : * us with a descriptor to a file that is about to be unlinked.
1077 : */
1078 0 : if (!v)
1079 0 : return;
1080 :
1081 : /* compute offset inside the current segment */
1082 0 : segnum_start = blocknum / RELSEG_SIZE;
1083 :
1084 : /* compute number of desired writes within the current segment */
1085 0 : segnum_end = (blocknum + nblocks - 1) / RELSEG_SIZE;
1086 0 : if (segnum_start != segnum_end)
1087 0 : nflush = RELSEG_SIZE - (blocknum % ((BlockNumber) RELSEG_SIZE));
1088 :
1089 : Assert(nflush >= 1);
1090 : Assert(nflush <= nblocks);
1091 :
1092 0 : seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
1093 :
1094 0 : FileWriteback(v->mdfd_vfd, seekpos, (off_t) BLCKSZ * nflush, WAIT_EVENT_DATA_FILE_FLUSH);
1095 :
1096 0 : nblocks -= nflush;
1097 0 : blocknum += nflush;
1098 : }
1099 : }
1100 :
1101 : /*
1102 : * mdnblocks() -- Get the number of blocks stored in a relation.
1103 : *
1104 : * Important side effect: all active segments of the relation are opened
1105 : * and added to the md_seg_fds array. If this routine has not been
1106 : * called, then only segments up to the last one actually touched
1107 : * are present in the array.
1108 : */
1109 : BlockNumber
1110 3850148 : mdnblocks(SMgrRelation reln, ForkNumber forknum)
1111 : {
1112 : MdfdVec *v;
1113 : BlockNumber nblocks;
1114 : BlockNumber segno;
1115 :
1116 3850148 : mdopenfork(reln, forknum, EXTENSION_FAIL);
1117 :
1118 : /* mdopen has opened the first segment */
1119 : Assert(reln->md_num_open_segs[forknum] > 0);
1120 :
1121 : /*
1122 : * Start from the last open segments, to avoid redundant seeks. We have
1123 : * previously verified that these segments are exactly RELSEG_SIZE long,
1124 : * and it's useless to recheck that each time.
1125 : *
1126 : * NOTE: this assumption could only be wrong if another backend has
1127 : * truncated the relation. We rely on higher code levels to handle that
1128 : * scenario by closing and re-opening the md fd, which is handled via
1129 : * relcache flush. (Since the checkpointer doesn't participate in
1130 : * relcache flush, it could have segment entries for inactive segments;
1131 : * that's OK because the checkpointer never needs to compute relation
1132 : * size.)
1133 : */
1134 3850110 : segno = reln->md_num_open_segs[forknum] - 1;
1135 3850110 : v = &reln->md_seg_fds[forknum][segno];
1136 :
1137 : for (;;)
1138 : {
1139 3850110 : nblocks = _mdnblocks(reln, forknum, v);
1140 3850110 : if (nblocks > ((BlockNumber) RELSEG_SIZE))
1141 0 : elog(FATAL, "segment too big");
1142 3850110 : if (nblocks < ((BlockNumber) RELSEG_SIZE))
1143 3850110 : return (segno * ((BlockNumber) RELSEG_SIZE)) + nblocks;
1144 :
1145 : /*
1146 : * If segment is exactly RELSEG_SIZE, advance to next one.
1147 : */
1148 0 : segno++;
1149 :
1150 : /*
1151 : * We used to pass O_CREAT here, but that has the disadvantage that it
1152 : * might create a segment which has vanished through some operating
1153 : * system misadventure. In such a case, creating the segment here
1154 : * undermines _mdfd_getseg's attempts to notice and report an error
1155 : * upon access to a missing segment.
1156 : */
1157 0 : v = _mdfd_openseg(reln, forknum, segno, 0);
1158 0 : if (v == NULL)
1159 0 : return segno * ((BlockNumber) RELSEG_SIZE);
1160 : }
1161 : }
1162 :
1163 : /*
1164 : * mdtruncate() -- Truncate relation to specified number of blocks.
1165 : */
1166 : void
1167 1570 : mdtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks)
1168 : {
1169 : BlockNumber curnblk;
1170 : BlockNumber priorblocks;
1171 : int curopensegs;
1172 :
1173 : /*
1174 : * NOTE: mdnblocks makes sure we have opened all active segments, so that
1175 : * truncation loop will get them all!
1176 : */
1177 1570 : curnblk = mdnblocks(reln, forknum);
1178 1570 : if (nblocks > curnblk)
1179 : {
1180 : /* Bogus request ... but no complaint if InRecovery */
1181 0 : if (InRecovery)
1182 0 : return;
1183 0 : ereport(ERROR,
1184 : (errmsg("could not truncate file \"%s\" to %u blocks: it's only %u blocks now",
1185 : relpath(reln->smgr_rlocator, forknum),
1186 : nblocks, curnblk)));
1187 : }
1188 1570 : if (nblocks == curnblk)
1189 646 : return; /* no work */
1190 :
1191 : /*
1192 : * Truncate segments, starting at the last one. Starting at the end makes
1193 : * managing the memory for the fd array easier, should there be errors.
1194 : */
1195 924 : curopensegs = reln->md_num_open_segs[forknum];
1196 1848 : while (curopensegs > 0)
1197 : {
1198 : MdfdVec *v;
1199 :
1200 924 : priorblocks = (curopensegs - 1) * RELSEG_SIZE;
1201 :
1202 924 : v = &reln->md_seg_fds[forknum][curopensegs - 1];
1203 :
1204 924 : if (priorblocks > nblocks)
1205 : {
1206 : /*
1207 : * This segment is no longer active. We truncate the file, but do
1208 : * not delete it, for reasons explained in the header comments.
1209 : */
1210 0 : if (FileTruncate(v->mdfd_vfd, 0, WAIT_EVENT_DATA_FILE_TRUNCATE) < 0)
1211 0 : ereport(ERROR,
1212 : (errcode_for_file_access(),
1213 : errmsg("could not truncate file \"%s\": %m",
1214 : FilePathName(v->mdfd_vfd))));
1215 :
1216 0 : if (!SmgrIsTemp(reln))
1217 0 : register_dirty_segment(reln, forknum, v);
1218 :
1219 : /* we never drop the 1st segment */
1220 : Assert(v != &reln->md_seg_fds[forknum][0]);
1221 :
1222 0 : FileClose(v->mdfd_vfd);
1223 0 : _fdvec_resize(reln, forknum, curopensegs - 1);
1224 : }
1225 924 : else if (priorblocks + ((BlockNumber) RELSEG_SIZE) > nblocks)
1226 : {
1227 : /*
1228 : * This is the last segment we want to keep. Truncate the file to
1229 : * the right length. NOTE: if nblocks is exactly a multiple K of
1230 : * RELSEG_SIZE, we will truncate the K+1st segment to 0 length but
1231 : * keep it. This adheres to the invariant given in the header
1232 : * comments.
1233 : */
1234 924 : BlockNumber lastsegblocks = nblocks - priorblocks;
1235 :
1236 924 : if (FileTruncate(v->mdfd_vfd, (off_t) lastsegblocks * BLCKSZ, WAIT_EVENT_DATA_FILE_TRUNCATE) < 0)
1237 0 : ereport(ERROR,
1238 : (errcode_for_file_access(),
1239 : errmsg("could not truncate file \"%s\" to %u blocks: %m",
1240 : FilePathName(v->mdfd_vfd),
1241 : nblocks)));
1242 924 : if (!SmgrIsTemp(reln))
1243 650 : register_dirty_segment(reln, forknum, v);
1244 : }
1245 : else
1246 : {
1247 : /*
1248 : * We still need this segment, so nothing to do for this and any
1249 : * earlier segment.
1250 : */
1251 0 : break;
1252 : }
1253 924 : curopensegs--;
1254 : }
1255 : }
1256 :
1257 : /*
1258 : * mdregistersync() -- Mark whole relation as needing fsync
1259 : */
1260 : void
1261 46096 : mdregistersync(SMgrRelation reln, ForkNumber forknum)
1262 : {
1263 : int segno;
1264 : int min_inactive_seg;
1265 :
1266 : /*
1267 : * NOTE: mdnblocks makes sure we have opened all active segments, so that
1268 : * the loop below will get them all!
1269 : */
1270 46096 : mdnblocks(reln, forknum);
1271 :
1272 46096 : min_inactive_seg = segno = reln->md_num_open_segs[forknum];
1273 :
1274 : /*
1275 : * Temporarily open inactive segments, then close them after sync. There
1276 : * may be some inactive segments left opened after error, but that is
1277 : * harmless. We don't bother to clean them up and take a risk of further
1278 : * trouble. The next mdclose() will soon close them.
1279 : */
1280 46096 : while (_mdfd_openseg(reln, forknum, segno, 0) != NULL)
1281 0 : segno++;
1282 :
1283 92192 : while (segno > 0)
1284 : {
1285 46096 : MdfdVec *v = &reln->md_seg_fds[forknum][segno - 1];
1286 :
1287 46096 : register_dirty_segment(reln, forknum, v);
1288 :
1289 : /* Close inactive segments immediately */
1290 46096 : if (segno > min_inactive_seg)
1291 : {
1292 0 : FileClose(v->mdfd_vfd);
1293 0 : _fdvec_resize(reln, forknum, segno - 1);
1294 : }
1295 :
1296 46096 : segno--;
1297 : }
1298 46096 : }
1299 :
1300 : /*
1301 : * mdimmedsync() -- Immediately sync a relation to stable storage.
1302 : *
1303 : * Note that only writes already issued are synced; this routine knows
1304 : * nothing of dirty buffers that may exist inside the buffer manager. We
1305 : * sync active and inactive segments; smgrDoPendingSyncs() relies on this.
1306 : * Consider a relation skipping WAL. Suppose a checkpoint syncs blocks of
1307 : * some segment, then mdtruncate() renders that segment inactive. If we
1308 : * crash before the next checkpoint syncs the newly-inactive segment, that
1309 : * segment may survive recovery, reintroducing unwanted data into the table.
1310 : */
1311 : void
1312 24 : mdimmedsync(SMgrRelation reln, ForkNumber forknum)
1313 : {
1314 : int segno;
1315 : int min_inactive_seg;
1316 :
1317 : /*
1318 : * NOTE: mdnblocks makes sure we have opened all active segments, so that
1319 : * the loop below will get them all!
1320 : */
1321 24 : mdnblocks(reln, forknum);
1322 :
1323 24 : min_inactive_seg = segno = reln->md_num_open_segs[forknum];
1324 :
1325 : /*
1326 : * Temporarily open inactive segments, then close them after sync. There
1327 : * may be some inactive segments left opened after fsync() error, but that
1328 : * is harmless. We don't bother to clean them up and take a risk of
1329 : * further trouble. The next mdclose() will soon close them.
1330 : */
1331 24 : while (_mdfd_openseg(reln, forknum, segno, 0) != NULL)
1332 0 : segno++;
1333 :
1334 48 : while (segno > 0)
1335 : {
1336 24 : MdfdVec *v = &reln->md_seg_fds[forknum][segno - 1];
1337 :
1338 : /*
1339 : * fsyncs done through mdimmedsync() should be tracked in a separate
1340 : * IOContext than those done through mdsyncfiletag() to differentiate
1341 : * between unavoidable client backend fsyncs (e.g. those done during
1342 : * index build) and those which ideally would have been done by the
1343 : * checkpointer. Since other IO operations bypassing the buffer
1344 : * manager could also be tracked in such an IOContext, wait until
1345 : * these are also tracked to track immediate fsyncs.
1346 : */
1347 24 : if (FileSync(v->mdfd_vfd, WAIT_EVENT_DATA_FILE_IMMEDIATE_SYNC) < 0)
1348 0 : ereport(data_sync_elevel(ERROR),
1349 : (errcode_for_file_access(),
1350 : errmsg("could not fsync file \"%s\": %m",
1351 : FilePathName(v->mdfd_vfd))));
1352 :
1353 : /* Close inactive segments immediately */
1354 24 : if (segno > min_inactive_seg)
1355 : {
1356 0 : FileClose(v->mdfd_vfd);
1357 0 : _fdvec_resize(reln, forknum, segno - 1);
1358 : }
1359 :
1360 24 : segno--;
1361 : }
1362 24 : }
1363 :
1364 : /*
1365 : * register_dirty_segment() -- Mark a relation segment as needing fsync
1366 : *
1367 : * If there is a local pending-ops table, just make an entry in it for
1368 : * ProcessSyncRequests to process later. Otherwise, try to pass off the
1369 : * fsync request to the checkpointer process. If that fails, just do the
1370 : * fsync locally before returning (we hope this will not happen often
1371 : * enough to be a performance problem).
1372 : */
1373 : static void
1374 1646420 : register_dirty_segment(SMgrRelation reln, ForkNumber forknum, MdfdVec *seg)
1375 : {
1376 : FileTag tag;
1377 :
1378 1646420 : INIT_MD_FILETAG(tag, reln->smgr_rlocator.locator, forknum, seg->mdfd_segno);
1379 :
1380 : /* Temp relations should never be fsync'd */
1381 : Assert(!SmgrIsTemp(reln));
1382 :
1383 1646420 : if (!RegisterSyncRequest(&tag, SYNC_REQUEST, false /* retryOnError */ ))
1384 : {
1385 : instr_time io_start;
1386 :
1387 2162 : ereport(DEBUG1,
1388 : (errmsg_internal("could not forward fsync request because request queue is full")));
1389 :
1390 2162 : io_start = pgstat_prepare_io_time(track_io_timing);
1391 :
1392 2162 : if (FileSync(seg->mdfd_vfd, WAIT_EVENT_DATA_FILE_SYNC) < 0)
1393 0 : ereport(data_sync_elevel(ERROR),
1394 : (errcode_for_file_access(),
1395 : errmsg("could not fsync file \"%s\": %m",
1396 : FilePathName(seg->mdfd_vfd))));
1397 :
1398 : /*
1399 : * We have no way of knowing if the current IOContext is
1400 : * IOCONTEXT_NORMAL or IOCONTEXT_[BULKREAD, BULKWRITE, VACUUM] at this
1401 : * point, so count the fsync as being in the IOCONTEXT_NORMAL
1402 : * IOContext. This is probably okay, because the number of backend
1403 : * fsyncs doesn't say anything about the efficacy of the
1404 : * BufferAccessStrategy. And counting both fsyncs done in
1405 : * IOCONTEXT_NORMAL and IOCONTEXT_[BULKREAD, BULKWRITE, VACUUM] under
1406 : * IOCONTEXT_NORMAL is likely clearer when investigating the number of
1407 : * backend fsyncs.
1408 : */
1409 2162 : pgstat_count_io_op_time(IOOBJECT_RELATION, IOCONTEXT_NORMAL,
1410 : IOOP_FSYNC, io_start, 1);
1411 : }
1412 1646420 : }
1413 :
1414 : /*
1415 : * register_unlink_segment() -- Schedule a file to be deleted after next checkpoint
1416 : */
1417 : static void
1418 66480 : register_unlink_segment(RelFileLocatorBackend rlocator, ForkNumber forknum,
1419 : BlockNumber segno)
1420 : {
1421 : FileTag tag;
1422 :
1423 66480 : INIT_MD_FILETAG(tag, rlocator.locator, forknum, segno);
1424 :
1425 : /* Should never be used with temp relations */
1426 : Assert(!RelFileLocatorBackendIsTemp(rlocator));
1427 :
1428 66480 : RegisterSyncRequest(&tag, SYNC_UNLINK_REQUEST, true /* retryOnError */ );
1429 66480 : }
1430 :
1431 : /*
1432 : * register_forget_request() -- forget any fsyncs for a relation fork's segment
1433 : */
1434 : static void
1435 257088 : register_forget_request(RelFileLocatorBackend rlocator, ForkNumber forknum,
1436 : BlockNumber segno)
1437 : {
1438 : FileTag tag;
1439 :
1440 257088 : INIT_MD_FILETAG(tag, rlocator.locator, forknum, segno);
1441 :
1442 257088 : RegisterSyncRequest(&tag, SYNC_FORGET_REQUEST, true /* retryOnError */ );
1443 257088 : }
1444 :
1445 : /*
1446 : * ForgetDatabaseSyncRequests -- forget any fsyncs and unlinks for a DB
1447 : */
1448 : void
1449 96 : ForgetDatabaseSyncRequests(Oid dbid)
1450 : {
1451 : FileTag tag;
1452 : RelFileLocator rlocator;
1453 :
1454 96 : rlocator.dbOid = dbid;
1455 96 : rlocator.spcOid = 0;
1456 96 : rlocator.relNumber = 0;
1457 :
1458 96 : INIT_MD_FILETAG(tag, rlocator, InvalidForkNumber, InvalidBlockNumber);
1459 :
1460 96 : RegisterSyncRequest(&tag, SYNC_FILTER_REQUEST, true /* retryOnError */ );
1461 96 : }
1462 :
1463 : /*
1464 : * DropRelationFiles -- drop files of all given relations
1465 : */
1466 : void
1467 5118 : DropRelationFiles(RelFileLocator *delrels, int ndelrels, bool isRedo)
1468 : {
1469 : SMgrRelation *srels;
1470 : int i;
1471 :
1472 5118 : srels = palloc(sizeof(SMgrRelation) * ndelrels);
1473 19538 : for (i = 0; i < ndelrels; i++)
1474 : {
1475 14420 : SMgrRelation srel = smgropen(delrels[i], INVALID_PROC_NUMBER);
1476 :
1477 14420 : if (isRedo)
1478 : {
1479 : ForkNumber fork;
1480 :
1481 71860 : for (fork = 0; fork <= MAX_FORKNUM; fork++)
1482 57488 : XLogDropRelation(delrels[i], fork);
1483 : }
1484 14420 : srels[i] = srel;
1485 : }
1486 :
1487 5118 : smgrdounlinkall(srels, ndelrels, isRedo);
1488 :
1489 19538 : for (i = 0; i < ndelrels; i++)
1490 14420 : smgrclose(srels[i]);
1491 5118 : pfree(srels);
1492 5118 : }
1493 :
1494 :
1495 : /*
1496 : * _fdvec_resize() -- Resize the fork's open segments array
1497 : */
1498 : static void
1499 2567434 : _fdvec_resize(SMgrRelation reln,
1500 : ForkNumber forknum,
1501 : int nseg)
1502 : {
1503 2567434 : if (nseg == 0)
1504 : {
1505 960736 : if (reln->md_num_open_segs[forknum] > 0)
1506 : {
1507 960736 : pfree(reln->md_seg_fds[forknum]);
1508 960736 : reln->md_seg_fds[forknum] = NULL;
1509 : }
1510 : }
1511 1606698 : else if (reln->md_num_open_segs[forknum] == 0)
1512 : {
1513 1606698 : reln->md_seg_fds[forknum] =
1514 1606698 : MemoryContextAlloc(MdCxt, sizeof(MdfdVec) * nseg);
1515 : }
1516 : else
1517 : {
1518 : /*
1519 : * It doesn't seem worthwhile complicating the code to amortize
1520 : * repalloc() calls. Those are far faster than PathNameOpenFile() or
1521 : * FileClose(), and the memory context internally will sometimes avoid
1522 : * doing an actual reallocation.
1523 : */
1524 0 : reln->md_seg_fds[forknum] =
1525 0 : repalloc(reln->md_seg_fds[forknum],
1526 : sizeof(MdfdVec) * nseg);
1527 : }
1528 :
1529 2567434 : reln->md_num_open_segs[forknum] = nseg;
1530 2567434 : }
1531 :
1532 : /*
1533 : * Return the filename for the specified segment of the relation. The
1534 : * returned string is palloc'd.
1535 : */
1536 : static char *
1537 46144 : _mdfd_segpath(SMgrRelation reln, ForkNumber forknum, BlockNumber segno)
1538 : {
1539 : char *path,
1540 : *fullpath;
1541 :
1542 46144 : path = relpath(reln->smgr_rlocator, forknum);
1543 :
1544 46144 : if (segno > 0)
1545 : {
1546 46144 : fullpath = psprintf("%s.%u", path, segno);
1547 46144 : pfree(path);
1548 : }
1549 : else
1550 0 : fullpath = path;
1551 :
1552 46144 : return fullpath;
1553 : }
1554 :
1555 : /*
1556 : * Open the specified segment of the relation,
1557 : * and make a MdfdVec object for it. Returns NULL on failure.
1558 : */
1559 : static MdfdVec *
1560 46120 : _mdfd_openseg(SMgrRelation reln, ForkNumber forknum, BlockNumber segno,
1561 : int oflags)
1562 : {
1563 : MdfdVec *v;
1564 : File fd;
1565 : char *fullpath;
1566 :
1567 46120 : fullpath = _mdfd_segpath(reln, forknum, segno);
1568 :
1569 : /* open the file */
1570 46120 : fd = PathNameOpenFile(fullpath, _mdfd_open_flags() | oflags);
1571 :
1572 46120 : pfree(fullpath);
1573 :
1574 46120 : if (fd < 0)
1575 46120 : return NULL;
1576 :
1577 : /*
1578 : * Segments are always opened in order from lowest to highest, so we must
1579 : * be adding a new one at the end.
1580 : */
1581 : Assert(segno == reln->md_num_open_segs[forknum]);
1582 :
1583 0 : _fdvec_resize(reln, forknum, segno + 1);
1584 :
1585 : /* fill the entry */
1586 0 : v = &reln->md_seg_fds[forknum][segno];
1587 0 : v->mdfd_vfd = fd;
1588 0 : v->mdfd_segno = segno;
1589 :
1590 : Assert(_mdnblocks(reln, forknum, v) <= ((BlockNumber) RELSEG_SIZE));
1591 :
1592 : /* all done */
1593 0 : return v;
1594 : }
1595 :
1596 : /*
1597 : * _mdfd_getseg() -- Find the segment of the relation holding the
1598 : * specified block.
1599 : *
1600 : * If the segment doesn't exist, we ereport, return NULL, or create the
1601 : * segment, according to "behavior". Note: skipFsync is only used in the
1602 : * EXTENSION_CREATE case.
1603 : */
1604 : static MdfdVec *
1605 3820058 : _mdfd_getseg(SMgrRelation reln, ForkNumber forknum, BlockNumber blkno,
1606 : bool skipFsync, int behavior)
1607 : {
1608 : MdfdVec *v;
1609 : BlockNumber targetseg;
1610 : BlockNumber nextsegno;
1611 :
1612 : /* some way to handle non-existent segments needs to be specified */
1613 : Assert(behavior &
1614 : (EXTENSION_FAIL | EXTENSION_CREATE | EXTENSION_RETURN_NULL |
1615 : EXTENSION_DONT_OPEN));
1616 :
1617 3820058 : targetseg = blkno / ((BlockNumber) RELSEG_SIZE);
1618 :
1619 : /* if an existing and opened segment, we're done */
1620 3820058 : if (targetseg < reln->md_num_open_segs[forknum])
1621 : {
1622 3444256 : v = &reln->md_seg_fds[forknum][targetseg];
1623 3444256 : return v;
1624 : }
1625 :
1626 : /* The caller only wants the segment if we already had it open. */
1627 375802 : if (behavior & EXTENSION_DONT_OPEN)
1628 0 : return NULL;
1629 :
1630 : /*
1631 : * The target segment is not yet open. Iterate over all the segments
1632 : * between the last opened and the target segment. This way missing
1633 : * segments either raise an error, or get created (according to
1634 : * 'behavior'). Start with either the last opened, or the first segment if
1635 : * none was opened before.
1636 : */
1637 375802 : if (reln->md_num_open_segs[forknum] > 0)
1638 24 : v = &reln->md_seg_fds[forknum][reln->md_num_open_segs[forknum] - 1];
1639 : else
1640 : {
1641 375778 : v = mdopenfork(reln, forknum, behavior);
1642 375772 : if (!v)
1643 0 : return NULL; /* if behavior & EXTENSION_RETURN_NULL */
1644 : }
1645 :
1646 375796 : for (nextsegno = reln->md_num_open_segs[forknum];
1647 0 : nextsegno <= targetseg; nextsegno++)
1648 : {
1649 24 : BlockNumber nblocks = _mdnblocks(reln, forknum, v);
1650 24 : int flags = 0;
1651 :
1652 : Assert(nextsegno == v->mdfd_segno + 1);
1653 :
1654 24 : if (nblocks > ((BlockNumber) RELSEG_SIZE))
1655 0 : elog(FATAL, "segment too big");
1656 :
1657 24 : if ((behavior & EXTENSION_CREATE) ||
1658 24 : (InRecovery && (behavior & EXTENSION_CREATE_RECOVERY)))
1659 : {
1660 : /*
1661 : * Normally we will create new segments only if authorized by the
1662 : * caller (i.e., we are doing mdextend()). But when doing WAL
1663 : * recovery, create segments anyway; this allows cases such as
1664 : * replaying WAL data that has a write into a high-numbered
1665 : * segment of a relation that was later deleted. We want to go
1666 : * ahead and create the segments so we can finish out the replay.
1667 : *
1668 : * We have to maintain the invariant that segments before the last
1669 : * active segment are of size RELSEG_SIZE; therefore, if
1670 : * extending, pad them out with zeroes if needed. (This only
1671 : * matters if in recovery, or if the caller is extending the
1672 : * relation discontiguously, but that can happen in hash indexes.)
1673 : */
1674 0 : if (nblocks < ((BlockNumber) RELSEG_SIZE))
1675 : {
1676 0 : char *zerobuf = palloc_aligned(BLCKSZ, PG_IO_ALIGN_SIZE,
1677 : MCXT_ALLOC_ZERO);
1678 :
1679 0 : mdextend(reln, forknum,
1680 0 : nextsegno * ((BlockNumber) RELSEG_SIZE) - 1,
1681 : zerobuf, skipFsync);
1682 0 : pfree(zerobuf);
1683 : }
1684 0 : flags = O_CREAT;
1685 : }
1686 24 : else if (!(behavior & EXTENSION_DONT_CHECK_SIZE) &&
1687 : nblocks < ((BlockNumber) RELSEG_SIZE))
1688 : {
1689 : /*
1690 : * When not extending (or explicitly including truncated
1691 : * segments), only open the next segment if the current one is
1692 : * exactly RELSEG_SIZE. If not (this branch), either return NULL
1693 : * or fail.
1694 : */
1695 24 : if (behavior & EXTENSION_RETURN_NULL)
1696 : {
1697 : /*
1698 : * Some callers discern between reasons for _mdfd_getseg()
1699 : * returning NULL based on errno. As there's no failing
1700 : * syscall involved in this case, explicitly set errno to
1701 : * ENOENT, as that seems the closest interpretation.
1702 : */
1703 0 : errno = ENOENT;
1704 0 : return NULL;
1705 : }
1706 :
1707 24 : ereport(ERROR,
1708 : (errcode_for_file_access(),
1709 : errmsg("could not open file \"%s\" (target block %u): previous segment is only %u blocks",
1710 : _mdfd_segpath(reln, forknum, nextsegno),
1711 : blkno, nblocks)));
1712 : }
1713 :
1714 0 : v = _mdfd_openseg(reln, forknum, nextsegno, flags);
1715 :
1716 0 : if (v == NULL)
1717 : {
1718 0 : if ((behavior & EXTENSION_RETURN_NULL) &&
1719 0 : FILE_POSSIBLY_DELETED(errno))
1720 0 : return NULL;
1721 0 : ereport(ERROR,
1722 : (errcode_for_file_access(),
1723 : errmsg("could not open file \"%s\" (target block %u): %m",
1724 : _mdfd_segpath(reln, forknum, nextsegno),
1725 : blkno)));
1726 : }
1727 : }
1728 :
1729 375772 : return v;
1730 : }
1731 :
1732 : /*
1733 : * Get number of blocks present in a single disk file
1734 : */
1735 : static BlockNumber
1736 3850134 : _mdnblocks(SMgrRelation reln, ForkNumber forknum, MdfdVec *seg)
1737 : {
1738 : off_t len;
1739 :
1740 3850134 : len = FileSize(seg->mdfd_vfd);
1741 3850134 : if (len < 0)
1742 0 : ereport(ERROR,
1743 : (errcode_for_file_access(),
1744 : errmsg("could not seek to end of file \"%s\": %m",
1745 : FilePathName(seg->mdfd_vfd))));
1746 : /* note that this calculation will ignore any partial block at EOF */
1747 3850134 : return (BlockNumber) (len / BLCKSZ);
1748 : }
1749 :
1750 : /*
1751 : * Sync a file to disk, given a file tag. Write the path into an output
1752 : * buffer so the caller can use it in error messages.
1753 : *
1754 : * Return 0 on success, -1 on failure, with errno set.
1755 : */
1756 : int
1757 0 : mdsyncfiletag(const FileTag *ftag, char *path)
1758 : {
1759 0 : SMgrRelation reln = smgropen(ftag->rlocator, INVALID_PROC_NUMBER);
1760 : File file;
1761 : instr_time io_start;
1762 : bool need_to_close;
1763 : int result,
1764 : save_errno;
1765 :
1766 : /* See if we already have the file open, or need to open it. */
1767 0 : if (ftag->segno < reln->md_num_open_segs[ftag->forknum])
1768 : {
1769 0 : file = reln->md_seg_fds[ftag->forknum][ftag->segno].mdfd_vfd;
1770 0 : strlcpy(path, FilePathName(file), MAXPGPATH);
1771 0 : need_to_close = false;
1772 : }
1773 : else
1774 : {
1775 : char *p;
1776 :
1777 0 : p = _mdfd_segpath(reln, ftag->forknum, ftag->segno);
1778 0 : strlcpy(path, p, MAXPGPATH);
1779 0 : pfree(p);
1780 :
1781 0 : file = PathNameOpenFile(path, _mdfd_open_flags());
1782 0 : if (file < 0)
1783 0 : return -1;
1784 0 : need_to_close = true;
1785 : }
1786 :
1787 0 : io_start = pgstat_prepare_io_time(track_io_timing);
1788 :
1789 : /* Sync the file. */
1790 0 : result = FileSync(file, WAIT_EVENT_DATA_FILE_SYNC);
1791 0 : save_errno = errno;
1792 :
1793 0 : if (need_to_close)
1794 0 : FileClose(file);
1795 :
1796 0 : pgstat_count_io_op_time(IOOBJECT_RELATION, IOCONTEXT_NORMAL,
1797 : IOOP_FSYNC, io_start, 1);
1798 :
1799 0 : errno = save_errno;
1800 0 : return result;
1801 : }
1802 :
1803 : /*
1804 : * Unlink a file, given a file tag. Write the path into an output
1805 : * buffer so the caller can use it in error messages.
1806 : *
1807 : * Return 0 on success, -1 on failure, with errno set.
1808 : */
1809 : int
1810 62738 : mdunlinkfiletag(const FileTag *ftag, char *path)
1811 : {
1812 : char *p;
1813 :
1814 : /* Compute the path. */
1815 62738 : p = relpathperm(ftag->rlocator, MAIN_FORKNUM);
1816 62738 : strlcpy(path, p, MAXPGPATH);
1817 62738 : pfree(p);
1818 :
1819 : /* Try to unlink the file. */
1820 62738 : return unlink(path);
1821 : }
1822 :
1823 : /*
1824 : * Check if a given candidate request matches a given tag, when processing
1825 : * a SYNC_FILTER_REQUEST request. This will be called for all pending
1826 : * requests to find out whether to forget them.
1827 : */
1828 : bool
1829 12836 : mdfiletagmatches(const FileTag *ftag, const FileTag *candidate)
1830 : {
1831 : /*
1832 : * For now we only use filter requests as a way to drop all scheduled
1833 : * callbacks relating to a given database, when dropping the database.
1834 : * We'll return true for all candidates that have the same database OID as
1835 : * the ftag from the SYNC_FILTER_REQUEST request, so they're forgotten.
1836 : */
1837 12836 : return ftag->rlocator.dbOid == candidate->rlocator.dbOid;
1838 : }
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