Branch data Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * filemap.c
4 : : * A data structure for keeping track of files that have changed.
5 : : *
6 : : * This source file contains the logic to decide what to do with different
7 : : * kinds of files, and the data structure to support it. Before modifying
8 : : * anything, pg_rewind collects information about all the files and their
9 : : * attributes in the target and source data directories. It also scans the
10 : : * WAL log in the target, and collects information about data blocks that
11 : : * were changed. All this information is stored in a hash table, using the
12 : : * file path relative to the root of the data directory as the key.
13 : : *
14 : : * After collecting all the information required, the decide_file_actions()
15 : : * function scans the hash table and decides what action needs to be taken
16 : : * for each file. Finally, it sorts the array to the final order that the
17 : : * actions should be executed in.
18 : : *
19 : : * Copyright (c) 2013-2026, PostgreSQL Global Development Group
20 : : *
21 : : *-------------------------------------------------------------------------
22 : : */
23 : :
24 : : #include "postgres_fe.h"
25 : :
26 : : #include <sys/stat.h>
27 : : #include <unistd.h>
28 : :
29 : : #include "access/xlog_internal.h"
30 : : #include "catalog/pg_tablespace_d.h"
31 : : #include "common/file_utils.h"
32 : : #include "common/hashfn_unstable.h"
33 : : #include "common/string.h"
34 : : #include "datapagemap.h"
35 : : #include "filemap.h"
36 : : #include "pg_rewind.h"
37 : :
38 : : /*
39 : : * Define a hash table which we can use to store information about the files
40 : : * appearing in source and target systems.
41 : : */
42 : : #define SH_PREFIX filehash
43 : : #define SH_ELEMENT_TYPE file_entry_t
44 : : #define SH_KEY_TYPE const char *
45 : : #define SH_KEY path
46 : : #define SH_HASH_KEY(tb, key) hash_string(key)
47 : : #define SH_EQUAL(tb, a, b) (strcmp(a, b) == 0)
48 : : #define SH_SCOPE static inline
49 : : #define SH_RAW_ALLOCATOR pg_malloc0
50 : : #define SH_DECLARE
51 : : #define SH_DEFINE
52 : : #include "lib/simplehash.h"
53 : :
54 : : #define FILEHASH_INITIAL_SIZE 1000
55 : :
56 : : static filehash_hash *filehash;
57 : :
58 : : static file_content_type_t getFileContentType(const char *path);
59 : : static char *datasegpath(RelFileLocator rlocator, ForkNumber forknum,
60 : : BlockNumber segno);
61 : :
62 : : static file_entry_t *insert_filehash_entry(const char *path);
63 : : static file_entry_t *lookup_filehash_entry(const char *path);
64 : :
65 : : /*
66 : : * A separate hash table which tracks WAL files that must not be deleted.
67 : : */
68 : : typedef struct keepwal_entry
69 : : {
70 : : const char *path;
71 : : uint32 status;
72 : : } keepwal_entry;
73 : :
74 : : #define SH_PREFIX keepwal
75 : : #define SH_ELEMENT_TYPE keepwal_entry
76 : : #define SH_KEY_TYPE const char *
77 : : #define SH_KEY path
78 : : #define SH_HASH_KEY(tb, key) hash_string(key)
79 : : #define SH_EQUAL(tb, a, b) (strcmp(a, b) == 0)
80 : : #define SH_SCOPE static inline
81 : : #define SH_RAW_ALLOCATOR pg_malloc0
82 : : #define SH_DECLARE
83 : : #define SH_DEFINE
84 : : #include "lib/simplehash.h"
85 : :
86 : : #define KEEPWAL_INITIAL_SIZE 1000
87 : :
88 : :
89 : : static keepwal_hash *keepwal = NULL;
90 : : static bool keepwal_entry_exists(const char *path);
91 : :
92 : : static int final_filemap_cmp(const void *a, const void *b);
93 : :
94 : : static bool check_file_excluded(const char *path, bool is_source);
95 : :
96 : : /*
97 : : * Definition of one element part of an exclusion list, used to exclude
98 : : * contents when rewinding. "name" is the name of the file or path to
99 : : * check for exclusion. If "match_prefix" is true, any items matching
100 : : * the name as prefix are excluded.
101 : : */
102 : : struct exclude_list_item
103 : : {
104 : : const char *name;
105 : : bool match_prefix;
106 : : };
107 : :
108 : : /*
109 : : * The contents of these directories are removed or recreated during server
110 : : * start so they are not included in data processed by pg_rewind.
111 : : *
112 : : * Note: those lists should be kept in sync with what basebackup.c provides.
113 : : * Some of the values, contrary to what basebackup.c uses, are hardcoded as
114 : : * they are defined in backend-only headers. So this list is maintained
115 : : * with a best effort in mind.
116 : : */
117 : : static const char *const excludeDirContents[] =
118 : : {
119 : : /*
120 : : * Skip temporary statistics files. PG_STAT_TMP_DIR must be skipped
121 : : * because extensions like pg_stat_statements store data there.
122 : : */
123 : : "pg_stat_tmp", /* defined as PG_STAT_TMP_DIR */
124 : :
125 : : /*
126 : : * It is generally not useful to backup the contents of this directory
127 : : * even if the intention is to restore to another primary. See backup.sgml
128 : : * for a more detailed description.
129 : : */
130 : : "pg_replslot", /* defined as PG_REPLSLOT_DIR */
131 : :
132 : : /* Contents removed on startup, see dsm_cleanup_for_mmap(). */
133 : : "pg_dynshmem", /* defined as PG_DYNSHMEM_DIR */
134 : :
135 : : /* Contents removed on startup, see AsyncShmemInit(). */
136 : : "pg_notify",
137 : :
138 : : /*
139 : : * Old contents are loaded for possible debugging but are not required for
140 : : * normal operation, see SerialInit().
141 : : */
142 : : "pg_serial",
143 : :
144 : : /* Contents removed on startup, see DeleteAllExportedSnapshotFiles(). */
145 : : "pg_snapshots",
146 : :
147 : : /* Contents zeroed on startup, see StartupSUBTRANS(). */
148 : : "pg_subtrans",
149 : :
150 : : /* end of list */
151 : : NULL
152 : : };
153 : :
154 : : /*
155 : : * List of files excluded from filemap processing. Files are excluded
156 : : * if their prefix match.
157 : : */
158 : : static const struct exclude_list_item excludeFiles[] =
159 : : {
160 : : /* Skip auto conf temporary file. */
161 : : {"postgresql.auto.conf.tmp", false}, /* defined as PG_AUTOCONF_FILENAME */
162 : :
163 : : /* Skip current log file temporary file */
164 : : {"current_logfiles.tmp", false}, /* defined as
165 : : * LOG_METAINFO_DATAFILE_TMP */
166 : :
167 : : /* Skip relation cache because it is rebuilt on startup */
168 : : {"pg_internal.init", true}, /* defined as RELCACHE_INIT_FILENAME */
169 : :
170 : : /*
171 : : * If there is a backup_label or tablespace_map file, it indicates that a
172 : : * recovery failed and this cluster probably can't be rewound, but exclude
173 : : * them anyway if they are found.
174 : : */
175 : : {"backup_label", false}, /* defined as BACKUP_LABEL_FILE */
176 : : {"tablespace_map", false}, /* defined as TABLESPACE_MAP */
177 : :
178 : : /*
179 : : * If there's a backup_manifest, it belongs to a backup that was used to
180 : : * start this server. It is *not* correct for this backup. Our
181 : : * backup_manifest is injected into the backup separately if users want
182 : : * it.
183 : : */
184 : : {"backup_manifest", false},
185 : :
186 : : {"postmaster.pid", false},
187 : : {"postmaster.opts", false},
188 : :
189 : : /* end of list */
190 : : {NULL, false}
191 : : };
192 : :
193 : : /*
194 : : * Initialize the hash table for the file map.
195 : : */
196 : : void
197 : 15 : filehash_init(void)
198 : : {
199 : 15 : filehash = filehash_create(FILEHASH_INITIAL_SIZE, NULL);
200 : 15 : }
201 : :
202 : : /* Look up entry for 'path', creating a new one if it doesn't exist */
203 : : static file_entry_t *
204 : 36044 : insert_filehash_entry(const char *path)
205 : : {
206 : : file_entry_t *entry;
207 : : bool found;
208 : :
209 : 36044 : entry = filehash_insert(filehash, path, &found);
210 [ + + ]: 36044 : if (!found)
211 : : {
212 : 18760 : entry->path = pg_strdup(path);
213 : 18760 : entry->content_type = getFileContentType(path);
214 : :
215 : 18760 : entry->target_exists = false;
216 : 18760 : entry->target_type = FILE_TYPE_UNDEFINED;
217 : 18760 : entry->target_size = 0;
218 : 18760 : entry->target_link_target = NULL;
219 : 18760 : entry->target_pages_to_overwrite.bitmap = NULL;
220 : 18760 : entry->target_pages_to_overwrite.bitmapsize = 0;
221 : :
222 : 18760 : entry->source_exists = false;
223 : 18760 : entry->source_type = FILE_TYPE_UNDEFINED;
224 : 18760 : entry->source_size = 0;
225 : 18760 : entry->source_link_target = NULL;
226 : :
227 : 18760 : entry->action = FILE_ACTION_UNDECIDED;
228 : : }
229 : :
230 : 36044 : return entry;
231 : : }
232 : :
233 : : static file_entry_t *
234 : 84276 : lookup_filehash_entry(const char *path)
235 : : {
236 : 84276 : return filehash_lookup(filehash, path);
237 : : }
238 : :
239 : : /*
240 : : * Initialize a hash table to store WAL file names that must be kept.
241 : : */
242 : : void
243 : 15 : keepwal_init(void)
244 : : {
245 : : /* An initial hash size out of thin air */
246 : 15 : keepwal = keepwal_create(KEEPWAL_INITIAL_SIZE, NULL);
247 : 15 : }
248 : :
249 : : /* Mark the given file to prevent its removal */
250 : : void
251 : 20 : keepwal_add_entry(const char *path)
252 : : {
253 : : keepwal_entry *entry;
254 : : bool found;
255 : :
256 : : /* Should only be called with keepwal initialized */
257 : : Assert(keepwal != NULL);
258 : :
259 : 20 : entry = keepwal_insert(keepwal, path, &found);
260 : :
261 [ + - ]: 20 : if (!found)
262 : 20 : entry->path = pg_strdup(path);
263 : 20 : }
264 : :
265 : : /* Return true if file is marked as not to be removed, false otherwise */
266 : : static bool
267 : 694 : keepwal_entry_exists(const char *path)
268 : : {
269 : 694 : return keepwal_lookup(keepwal, path) != NULL;
270 : : }
271 : :
272 : : /*
273 : : * Callback for processing source file list.
274 : : *
275 : : * This is called once for every file in the source server. We record the
276 : : * type and size of the file, so that decide_file_action() can later decide what
277 : : * to do with it.
278 : : */
279 : : void
280 : 18042 : process_source_file(const char *path, file_type_t type, size_t size,
281 : : const char *link_target)
282 : : {
283 : : file_entry_t *entry;
284 : :
285 : : /*
286 : : * Pretend that pg_wal is a directory, even if it's really a symlink. We
287 : : * don't want to mess with the symlink itself, nor complain if it's a
288 : : * symlink in source but not in target or vice versa.
289 : : */
290 [ + + - + ]: 18042 : if (strcmp(path, "pg_wal") == 0 && type == FILE_TYPE_SYMLINK)
291 : 0 : type = FILE_TYPE_DIRECTORY;
292 : :
293 : : /*
294 : : * sanity check: a filename that looks like a data file better be a
295 : : * regular file
296 : : */
297 [ + + - + ]: 18042 : if (type != FILE_TYPE_REGULAR && getFileContentType(path) == FILE_CONTENT_TYPE_RELATION)
298 : 0 : pg_fatal("data file \"%s\" in source is not a regular file", path);
299 : :
300 : : /* Remember this source file */
301 : 18042 : entry = insert_filehash_entry(path);
302 [ - + ]: 18042 : if (entry->source_exists)
303 : 0 : pg_fatal("duplicate source file \"%s\"", path);
304 : 18042 : entry->source_exists = true;
305 : 18042 : entry->source_type = type;
306 : 18042 : entry->source_size = size;
307 [ + + ]: 18042 : entry->source_link_target = link_target ? pg_strdup(link_target) : NULL;
308 : 18042 : }
309 : :
310 : : /*
311 : : * Callback for processing target file list.
312 : : *
313 : : * Record the type and size of the file, like process_source_file() does.
314 : : */
315 : : void
316 : 18002 : process_target_file(const char *path, file_type_t type, size_t size,
317 : : const char *link_target)
318 : : {
319 : : file_entry_t *entry;
320 : :
321 : : /*
322 : : * Do not apply any exclusion filters here. This has advantage to remove
323 : : * from the target data folder all paths which have been filtered out from
324 : : * the source data folder when processing the source files.
325 : : */
326 : :
327 : : /*
328 : : * Like in process_source_file, pretend that pg_wal is always a directory.
329 : : */
330 [ + + + + ]: 18002 : if (strcmp(path, "pg_wal") == 0 && type == FILE_TYPE_SYMLINK)
331 : 2 : type = FILE_TYPE_DIRECTORY;
332 : :
333 : : /* Remember this target file */
334 : 18002 : entry = insert_filehash_entry(path);
335 [ - + ]: 18002 : if (entry->target_exists)
336 : 0 : pg_fatal("duplicate source file \"%s\"", path);
337 : 18002 : entry->target_exists = true;
338 : 18002 : entry->target_type = type;
339 : 18002 : entry->target_size = size;
340 [ + + ]: 18002 : entry->target_link_target = link_target ? pg_strdup(link_target) : NULL;
341 : 18002 : }
342 : :
343 : : /*
344 : : * This callback gets called while we read the WAL in the target, for every
345 : : * block that has changed in the target system. It decides if the given
346 : : * 'blkno' in the target relfile needs to be overwritten from the source, and
347 : : * if so, records it in 'target_pages_to_overwrite' bitmap.
348 : : *
349 : : * NOTE: All the files on both systems must have already been added to the
350 : : * hash table!
351 : : */
352 : : void
353 : 84276 : process_target_wal_block_change(ForkNumber forknum, RelFileLocator rlocator,
354 : : BlockNumber blkno)
355 : : {
356 : : char *path;
357 : : file_entry_t *entry;
358 : : BlockNumber blkno_inseg;
359 : : int segno;
360 : :
361 : 84276 : segno = blkno / RELSEG_SIZE;
362 : 84276 : blkno_inseg = blkno % RELSEG_SIZE;
363 : :
364 : 84276 : path = datasegpath(rlocator, forknum, segno);
365 : 84276 : entry = lookup_filehash_entry(path);
366 : 84276 : pfree(path);
367 : :
368 : : /*
369 : : * If the block still exists in both systems, remember it. Otherwise we
370 : : * can safely ignore it.
371 : : *
372 : : * If the block is beyond the EOF in the source system, or the file
373 : : * doesn't exist in the source at all, we're going to truncate/remove it
374 : : * away from the target anyway. Likewise, if it doesn't exist in the
375 : : * target anymore, we will copy it over with the "tail" from the source
376 : : * system, anyway.
377 : : *
378 : : * It is possible to find WAL for a file that doesn't exist on either
379 : : * system anymore. It means that the relation was dropped later in the
380 : : * target system, and independently on the source system too, or that it
381 : : * was created and dropped in the target system and it never existed in
382 : : * the source. Either way, we can safely ignore it.
383 : : */
384 [ + - ]: 84276 : if (entry)
385 : : {
386 : : Assert(entry->content_type == FILE_CONTENT_TYPE_RELATION);
387 : :
388 [ + + ]: 84276 : if (entry->target_exists)
389 : : {
390 [ - + ]: 84272 : if (entry->target_type != FILE_TYPE_REGULAR)
391 : 0 : pg_fatal("unexpected page modification for non-regular file \"%s\"",
392 : : entry->path);
393 : :
394 [ + + ]: 84272 : if (entry->source_exists)
395 : : {
396 : : off_t end_offset;
397 : :
398 : 82564 : end_offset = (blkno_inseg + 1) * BLCKSZ;
399 [ + + + + ]: 82564 : if (end_offset <= entry->source_size && end_offset <= entry->target_size)
400 : 2896 : datapagemap_add(&entry->target_pages_to_overwrite, blkno_inseg);
401 : : }
402 : : }
403 : : }
404 : 84276 : }
405 : :
406 : : /*
407 : : * Is this the path of file that pg_rewind can skip copying?
408 : : */
409 : : static bool
410 : 18743 : check_file_excluded(const char *path, bool is_source)
411 : : {
412 : : char localpath[MAXPGPATH];
413 : : int excludeIdx;
414 : : const char *filename;
415 : :
416 : : /*
417 : : * Skip all temporary files, .../pgsql_tmp/... and .../pgsql_tmp.*
418 : : */
419 [ + + ]: 18743 : if (strstr(path, "/" PG_TEMP_FILE_PREFIX) != NULL ||
420 [ - + ]: 18728 : strstr(path, "/" PG_TEMP_FILES_DIR "/") != NULL)
421 : : {
422 : 15 : return true;
423 : : }
424 : :
425 : : /* check individual files... */
426 [ + + ]: 168246 : for (excludeIdx = 0; excludeFiles[excludeIdx].name != NULL; excludeIdx++)
427 : : {
428 : 149593 : int cmplen = strlen(excludeFiles[excludeIdx].name);
429 : :
430 : 149593 : filename = last_dir_separator(path);
431 [ + + ]: 149593 : if (filename == NULL)
432 : 3220 : filename = path;
433 : : else
434 : 146373 : filename++;
435 : :
436 [ + + ]: 149593 : if (!excludeFiles[excludeIdx].match_prefix)
437 : 130865 : cmplen++;
438 [ + + ]: 149593 : if (strncmp(filename, excludeFiles[excludeIdx].name, cmplen) == 0)
439 : : {
440 [ + - ]: 75 : if (is_source)
441 [ + - ]: 75 : pg_log_debug("entry \"%s\" excluded from source file list",
442 : : path);
443 : : else
444 [ # # ]: 0 : pg_log_debug("entry \"%s\" excluded from target file list",
445 : : path);
446 : 75 : return true;
447 : : }
448 : : }
449 : :
450 : : /*
451 : : * ... And check some directories. Note that this includes any contents
452 : : * within the directories themselves.
453 : : */
454 [ + + ]: 149209 : for (excludeIdx = 0; excludeDirContents[excludeIdx] != NULL; excludeIdx++)
455 : : {
456 : 130571 : snprintf(localpath, sizeof(localpath), "%s/",
457 : 130571 : excludeDirContents[excludeIdx]);
458 [ + + ]: 130571 : if (strstr(path, localpath) == path)
459 : : {
460 [ + - ]: 15 : if (is_source)
461 [ + - ]: 15 : pg_log_debug("entry \"%s\" excluded from source file list",
462 : : path);
463 : : else
464 [ # # ]: 0 : pg_log_debug("entry \"%s\" excluded from target file list",
465 : : path);
466 : 15 : return true;
467 : : }
468 : : }
469 : :
470 : 18638 : return false;
471 : : }
472 : :
473 : : static const char *
474 : 5960 : action_to_str(file_action_t action)
475 : : {
476 [ + + + + : 5960 : switch (action)
+ + - ]
477 : : {
478 : 448 : case FILE_ACTION_NONE:
479 : 448 : return "NONE";
480 : 4729 : case FILE_ACTION_COPY:
481 : 4729 : return "COPY";
482 : 4 : case FILE_ACTION_TRUNCATE:
483 : 4 : return "TRUNCATE";
484 : 5 : case FILE_ACTION_COPY_TAIL:
485 : 5 : return "COPY_TAIL";
486 : 9 : case FILE_ACTION_CREATE:
487 : 9 : return "CREATE";
488 : 765 : case FILE_ACTION_REMOVE:
489 : 765 : return "REMOVE";
490 : :
491 : 0 : default:
492 : 0 : return "unknown";
493 : : }
494 : : }
495 : :
496 : : /*
497 : : * Calculate the totals needed for progress reports.
498 : : */
499 : : void
500 : 0 : calculate_totals(filemap_t *filemap)
501 : : {
502 : : file_entry_t *entry;
503 : : int i;
504 : :
505 : 0 : filemap->total_size = 0;
506 : 0 : filemap->fetch_size = 0;
507 : :
508 [ # # ]: 0 : for (i = 0; i < filemap->nentries; i++)
509 : : {
510 : 0 : entry = filemap->entries[i];
511 : :
512 [ # # ]: 0 : if (entry->source_type != FILE_TYPE_REGULAR)
513 : 0 : continue;
514 : :
515 : 0 : filemap->total_size += entry->source_size;
516 : :
517 [ # # ]: 0 : if (entry->action == FILE_ACTION_COPY)
518 : : {
519 : 0 : filemap->fetch_size += entry->source_size;
520 : 0 : continue;
521 : : }
522 : :
523 [ # # ]: 0 : if (entry->action == FILE_ACTION_COPY_TAIL)
524 : 0 : filemap->fetch_size += (entry->source_size - entry->target_size);
525 : :
526 [ # # ]: 0 : if (entry->target_pages_to_overwrite.bitmapsize > 0)
527 : : {
528 : : datapagemap_iterator_t *iter;
529 : : BlockNumber blk;
530 : :
531 : 0 : iter = datapagemap_iterate(&entry->target_pages_to_overwrite);
532 [ # # ]: 0 : while (datapagemap_next(iter, &blk))
533 : 0 : filemap->fetch_size += BLCKSZ;
534 : :
535 : 0 : pg_free(iter);
536 : : }
537 : : }
538 : 0 : }
539 : :
540 : : void
541 : 15 : print_filemap(filemap_t *filemap)
542 : : {
543 : : file_entry_t *entry;
544 : : int i;
545 : :
546 [ + + ]: 18775 : for (i = 0; i < filemap->nentries; i++)
547 : : {
548 : 18760 : entry = filemap->entries[i];
549 : :
550 [ + + ]: 18760 : if (entry->action != FILE_ACTION_NONE ||
551 [ + + ]: 13248 : entry->content_type == FILE_CONTENT_TYPE_WAL ||
552 [ + + ]: 13228 : entry->target_pages_to_overwrite.bitmapsize > 0)
553 : : {
554 [ + - ]: 5960 : pg_log_debug("%s (%s)", entry->path,
555 : : action_to_str(entry->action));
556 : :
557 [ + + ]: 5960 : if (entry->target_pages_to_overwrite.bitmapsize > 0)
558 : 436 : datapagemap_print(&entry->target_pages_to_overwrite);
559 : : }
560 : : }
561 : 15 : fflush(stdout);
562 : 15 : }
563 : :
564 : : /*
565 : : * Determine what kind of file this one looks like.
566 : : */
567 : : static file_content_type_t
568 : 19179 : getFileContentType(const char *path)
569 : : {
570 : : RelFileLocator rlocator;
571 : : unsigned int segNo;
572 : : int nmatch;
573 : 19179 : file_content_type_t result = FILE_CONTENT_TYPE_OTHER;
574 : :
575 : : /* Check if it is a WAL file. */
576 [ + + ]: 19179 : if (strncmp("pg_wal/", path, 7) == 0)
577 : : {
578 : 155 : const char *filename = path + 7; /* Skip "pg_wal/" */
579 : :
580 [ + + ]: 155 : if (IsXLogFileName(filename))
581 : 64 : return FILE_CONTENT_TYPE_WAL;
582 : : else
583 : 91 : return FILE_CONTENT_TYPE_OTHER;
584 : : }
585 : :
586 : : /*----
587 : : * Does it look like a relation data file?
588 : : *
589 : : * For our purposes, only files belonging to the main fork are considered
590 : : * relation files. Other forks are always copied in toto, because we
591 : : * cannot reliably track changes to them, because WAL only contains block
592 : : * references for the main fork.
593 : : *
594 : : * Relation data files can be in one of the following directories:
595 : : *
596 : : * global/
597 : : * shared relations
598 : : *
599 : : * base/<db oid>/
600 : : * regular relations, default tablespace
601 : : *
602 : : * pg_tblspc/<tblspc oid>/<tblspc version>/
603 : : * within a non-default tablespace (the name of the directory
604 : : * depends on version)
605 : : *
606 : : * And the relation data files themselves have a filename like:
607 : : *
608 : : * <oid>.<segment number>
609 : : *
610 : : *----
611 : : */
612 : 19024 : rlocator.spcOid = InvalidOid;
613 : 19024 : rlocator.dbOid = InvalidOid;
614 : 19024 : rlocator.relNumber = InvalidRelFileNumber;
615 : 19024 : segNo = 0;
616 : 19024 : result = FILE_CONTENT_TYPE_OTHER;
617 : :
618 : 19024 : nmatch = sscanf(path, "global/%u.%u", &rlocator.relNumber, &segNo);
619 [ + + - + ]: 19024 : if (nmatch == 1 || nmatch == 2)
620 : : {
621 : 840 : rlocator.spcOid = GLOBALTABLESPACE_OID;
622 : 840 : rlocator.dbOid = 0;
623 : 840 : result = FILE_CONTENT_TYPE_RELATION;
624 : : }
625 : : else
626 : : {
627 : 18184 : nmatch = sscanf(path, "base/%u/%u.%u",
628 : : &rlocator.dbOid, &rlocator.relNumber, &segNo);
629 [ + + - + ]: 18184 : if (nmatch == 2 || nmatch == 3)
630 : : {
631 : 16942 : rlocator.spcOid = DEFAULTTABLESPACE_OID;
632 : 16942 : result = FILE_CONTENT_TYPE_RELATION;
633 : : }
634 : : else
635 : : {
636 : 1242 : nmatch = sscanf(path, "pg_tblspc/%u/" TABLESPACE_VERSION_DIRECTORY "/%u/%u.%u",
637 : : &rlocator.spcOid, &rlocator.dbOid, &rlocator.relNumber,
638 : : &segNo);
639 [ + + - + ]: 1242 : if (nmatch == 3 || nmatch == 4)
640 : 12 : result = FILE_CONTENT_TYPE_RELATION;
641 : : }
642 : : }
643 : :
644 : : /*
645 : : * The sscanf tests above can match files that have extra characters at
646 : : * the end. To eliminate such cases, cross-check that GetRelationPath
647 : : * creates the exact same filename, when passed the RelFileLocator
648 : : * information we extracted from the filename.
649 : : */
650 [ + + ]: 19024 : if (result == FILE_CONTENT_TYPE_RELATION)
651 : : {
652 : 17794 : char *check_path = datasegpath(rlocator, MAIN_FORKNUM, segNo);
653 : :
654 [ + + ]: 17794 : if (strcmp(check_path, path) != 0)
655 : 4084 : result = FILE_CONTENT_TYPE_OTHER;
656 : :
657 : 17794 : pfree(check_path);
658 : : }
659 : :
660 : 19024 : return result;
661 : : }
662 : :
663 : : /*
664 : : * A helper function to create the path of a relation file and segment.
665 : : *
666 : : * The returned path is palloc'd
667 : : */
668 : : static char *
669 : 102070 : datasegpath(RelFileLocator rlocator, ForkNumber forknum, BlockNumber segno)
670 : : {
671 : : RelPathStr path;
672 : : char *segpath;
673 : :
674 : 102070 : path = relpathperm(rlocator, forknum);
675 [ - + ]: 102070 : if (segno > 0)
676 : : {
677 : 0 : segpath = psprintf("%s.%u", path.str, segno);
678 : 0 : return segpath;
679 : : }
680 : : else
681 : 102070 : return pstrdup(path.str);
682 : : }
683 : :
684 : : /*
685 : : * In the final stage, the filemap is sorted so that removals come last.
686 : : * From disk space usage point of view, it would be better to do removals
687 : : * first, but for now, safety first. If a whole directory is deleted, all
688 : : * files and subdirectories inside it need to removed first. On creation,
689 : : * parent directory needs to be created before files and directories inside
690 : : * it. To achieve that, the file_action_t enum is ordered so that we can
691 : : * just sort on that first. Furthermore, sort REMOVE entries in reverse
692 : : * path order, so that "foo/bar" subdirectory is removed before "foo".
693 : : */
694 : : static int
695 : 201299 : final_filemap_cmp(const void *a, const void *b)
696 : : {
697 : 201299 : file_entry_t *fa = *((file_entry_t *const *) a);
698 : 201299 : file_entry_t *fb = *((file_entry_t *const *) b);
699 : :
700 [ + + ]: 201299 : if (fa->action > fb->action)
701 : 6643 : return 1;
702 [ + + ]: 194656 : if (fa->action < fb->action)
703 : 9751 : return -1;
704 : :
705 [ + + ]: 184905 : if (fa->action == FILE_ACTION_REMOVE)
706 : 6084 : return strcmp(fb->path, fa->path);
707 : : else
708 : 178821 : return strcmp(fa->path, fb->path);
709 : : }
710 : :
711 : : /*
712 : : * Decide what to do with a WAL segment file based on its position
713 : : * relative to the point of divergence.
714 : : *
715 : : * Caller is responsible for ensuring that the file exists on both
716 : : * source and target servers.
717 : : */
718 : : static file_action_t
719 : 30 : decide_wal_file_action(const char *fname, XLogSegNo last_common_segno,
720 : : size_t source_size, size_t target_size)
721 : : {
722 : : TimeLineID file_tli;
723 : : XLogSegNo file_segno;
724 : :
725 : : /* Get current WAL segment number given current segment file name */
726 : 30 : XLogFromFileName(fname, &file_tli, &file_segno, WalSegSz);
727 : :
728 : : /*
729 : : * Avoid copying files before the last common segment.
730 : : *
731 : : * These files exist on the source and the target servers, so they should
732 : : * be identical and located strictly before the segment that contains the
733 : : * LSN where target and source servers have diverged.
734 : : *
735 : : * While we are on it, double-check the size of each file and copy the
736 : : * file if they do not match, in case.
737 : : */
738 [ + + + + ]: 30 : if (file_segno < last_common_segno &&
739 : : source_size == target_size)
740 : 16 : return FILE_ACTION_NONE;
741 : :
742 : 14 : return FILE_ACTION_COPY;
743 : : }
744 : :
745 : : /*
746 : : * Decide what action to perform to a file.
747 : : */
748 : : static file_action_t
749 : 18760 : decide_file_action(file_entry_t *entry, XLogSegNo last_common_segno)
750 : : {
751 : 18760 : const char *path = entry->path;
752 : :
753 : : /*
754 : : * Don't touch the control file. It is handled specially, after copying
755 : : * all the other files.
756 : : */
757 [ + + ]: 18760 : if (strcmp(path, XLOG_CONTROL_FILE) == 0)
758 : 15 : return FILE_ACTION_NONE;
759 : :
760 : : /* Skip macOS system files */
761 [ + + ]: 18745 : if (strstr(path, ".DS_Store") != NULL)
762 : 2 : return FILE_ACTION_NONE;
763 : :
764 : : /*
765 : : * Remove all files matching the exclusion filters in the target.
766 : : */
767 [ + + ]: 18743 : if (check_file_excluded(path, true))
768 : : {
769 [ + + ]: 105 : if (entry->target_exists)
770 : 75 : return FILE_ACTION_REMOVE;
771 : : else
772 : 30 : return FILE_ACTION_NONE;
773 : : }
774 : :
775 : : /*
776 : : * Handle cases where the file is missing from one of the systems.
777 : : */
778 [ + + + - ]: 18638 : if (!entry->target_exists && entry->source_exists)
779 : : {
780 : : /*
781 : : * File exists in source, but not in target. Copy it in toto. (If it's
782 : : * a relation data file, WAL replay after rewinding should re-create
783 : : * it anyway. But there's no harm in copying it now.)
784 : : */
785 [ + + - - ]: 726 : switch (entry->source_type)
786 : : {
787 : 9 : case FILE_TYPE_DIRECTORY:
788 : : case FILE_TYPE_SYMLINK:
789 : 9 : return FILE_ACTION_CREATE;
790 : 717 : case FILE_TYPE_REGULAR:
791 : 717 : return FILE_ACTION_COPY;
792 : 0 : case FILE_TYPE_UNDEFINED:
793 : 0 : pg_fatal("unknown file type for \"%s\"", entry->path);
794 : : break;
795 : : }
796 : : }
797 [ + - + + ]: 17912 : else if (entry->target_exists && !entry->source_exists)
798 : : {
799 : : /*
800 : : * For files that exist in target but not in source, we check the
801 : : * keepwal hash table; any files listed therein must not be removed.
802 : : */
803 [ + + ]: 694 : if (keepwal_entry_exists(path))
804 : : {
805 [ + - ]: 4 : pg_log_debug("Not removing file \"%s\" because it is required for recovery", path);
806 : 4 : return FILE_ACTION_NONE;
807 : : }
808 : 690 : return FILE_ACTION_REMOVE;
809 : : }
810 [ - + - - ]: 17218 : else if (!entry->target_exists && !entry->source_exists)
811 : : {
812 : : /*
813 : : * Doesn't exist in either server. Why does it have an entry in the
814 : : * first place??
815 : : */
816 : : Assert(false);
817 : 0 : return FILE_ACTION_NONE;
818 : : }
819 : :
820 : : /*
821 : : * Otherwise, the file exists on both systems
822 : : */
823 : : Assert(entry->target_exists && entry->source_exists);
824 : :
825 [ - + ]: 17218 : if (entry->source_type != entry->target_type)
826 : : {
827 : : /* But it's a different kind of object. Strange.. */
828 : 0 : pg_fatal("file \"%s\" is of different type in source and target", entry->path);
829 : : }
830 : :
831 : : /*
832 : : * PG_VERSION files should be identical on both systems, but avoid
833 : : * overwriting them for paranoia.
834 : : */
835 [ + + ]: 17218 : if (pg_str_endswith(entry->path, "PG_VERSION"))
836 : 64 : return FILE_ACTION_NONE;
837 : :
838 [ + - + - : 17154 : switch (entry->source_type)
- ]
839 : : {
840 : 408 : case FILE_TYPE_DIRECTORY:
841 : 408 : return FILE_ACTION_NONE;
842 : :
843 : 0 : case FILE_TYPE_SYMLINK:
844 : :
845 : : /*
846 : : * XXX: Should we check if it points to the same target?
847 : : */
848 : 0 : return FILE_ACTION_NONE;
849 : :
850 : 16746 : case FILE_TYPE_REGULAR:
851 [ + + ]: 16746 : if (entry->content_type == FILE_CONTENT_TYPE_WAL)
852 : : {
853 : : /* Handle WAL segment file */
854 : 30 : const char *filename = last_dir_separator(entry->path);
855 : :
856 [ - + ]: 30 : if (filename == NULL)
857 : 0 : filename = entry->path;
858 : : else
859 : 30 : filename++; /* Skip the separator */
860 : :
861 : 30 : return decide_wal_file_action(filename, last_common_segno,
862 : : entry->source_size,
863 : : entry->target_size);
864 : : }
865 [ + + ]: 16716 : else if (entry->content_type != FILE_CONTENT_TYPE_RELATION)
866 : : {
867 : : /*
868 : : * It's a non-data file that we have no special processing
869 : : * for. Copy it in toto.
870 : : */
871 : 3998 : return FILE_ACTION_COPY;
872 : : }
873 : : else
874 : : {
875 : : /*
876 : : * It's a data file that exists in both systems.
877 : : *
878 : : * If it's larger in target, we can truncate it. There will
879 : : * also be a WAL record of the truncation in the source
880 : : * system, so WAL replay would eventually truncate the target
881 : : * too, but we might as well do it now.
882 : : *
883 : : * If it's smaller in the target, it means that it has been
884 : : * truncated in the target, or enlarged in the source, or
885 : : * both. If it was truncated in the target, we need to copy
886 : : * the missing tail from the source system. If it was enlarged
887 : : * in the source system, there will be WAL records in the
888 : : * source system for the new blocks, so we wouldn't need to
889 : : * copy them here. But we don't know which scenario we're
890 : : * dealing with, and there's no harm in copying the missing
891 : : * blocks now, so do it now.
892 : : *
893 : : * If it's the same size, do nothing here. Any blocks modified
894 : : * in the target will be copied based on parsing the target
895 : : * system's WAL, and any blocks modified in the source will be
896 : : * updated after rewinding, when the source system's WAL is
897 : : * replayed.
898 : : */
899 [ + + ]: 12718 : if (entry->target_size < entry->source_size)
900 : 5 : return FILE_ACTION_COPY_TAIL;
901 [ + + ]: 12713 : else if (entry->target_size > entry->source_size)
902 : 4 : return FILE_ACTION_TRUNCATE;
903 : : else
904 : 12709 : return FILE_ACTION_NONE;
905 : : }
906 : : break;
907 : :
908 : 0 : case FILE_TYPE_UNDEFINED:
909 : 0 : pg_fatal("unknown file type for \"%s\"", path);
910 : : break;
911 : : }
912 : :
913 : : /* unreachable */
914 : 0 : pg_fatal("could not decide what to do with file \"%s\"", path);
915 : : }
916 : :
917 : : /*
918 : : * Decide what to do with each file.
919 : : *
920 : : * Returns a 'filemap' with the entries in the order that their actions
921 : : * should be executed.
922 : : */
923 : : filemap_t *
924 : 15 : decide_file_actions(XLogSegNo last_common_segno)
925 : : {
926 : : int i;
927 : : filehash_iterator it;
928 : : file_entry_t *entry;
929 : : filemap_t *filemap;
930 : :
931 : 15 : filehash_start_iterate(filehash, &it);
932 [ + + ]: 18775 : while ((entry = filehash_iterate(filehash, &it)) != NULL)
933 : : {
934 : 18760 : entry->action = decide_file_action(entry, last_common_segno);
935 : : }
936 : :
937 : : /*
938 : : * Turn the hash table into an array, and sort in the order that the
939 : : * actions should be performed.
940 : : */
941 : 15 : filemap = pg_malloc(offsetof(filemap_t, entries) +
942 : 15 : filehash->members * sizeof(file_entry_t *));
943 : 15 : filemap->nentries = filehash->members;
944 : 15 : filehash_start_iterate(filehash, &it);
945 : 15 : i = 0;
946 [ + + ]: 18775 : while ((entry = filehash_iterate(filehash, &it)) != NULL)
947 : : {
948 : 18760 : filemap->entries[i++] = entry;
949 : : }
950 : :
951 : 15 : qsort(&filemap->entries, filemap->nentries, sizeof(file_entry_t *),
952 : : final_filemap_cmp);
953 : :
954 : 15 : return filemap;
955 : : }
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