1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
4 * All Rights Reserved.
5 */
6#include "xfs.h"
7#include "xfs_fs.h"
8#include "xfs_shared.h"
9#include "xfs_format.h"
10#include "xfs_log_format.h"
11#include "xfs_trans_resv.h"
12#include "xfs_bit.h"
13#include "xfs_sb.h"
14#include "xfs_mount.h"
15#include "xfs_defer.h"
16#include "xfs_inode.h"
17#include "xfs_trans.h"
18#include "xfs_log.h"
19#include "xfs_log_priv.h"
20#include "xfs_log_recover.h"
21#include "xfs_trans_priv.h"
22#include "xfs_alloc.h"
23#include "xfs_ialloc.h"
24#include "xfs_trace.h"
25#include "xfs_icache.h"
26#include "xfs_error.h"
27#include "xfs_buf_item.h"
28#include "xfs_ag.h"
29#include "xfs_quota.h"
30#include "xfs_reflink.h"
31
32#define BLK_AVG(blk1, blk2) ((blk1+blk2) >> 1)
33
34STATIC int
35xlog_find_zeroed(
36 struct xlog *,
37 xfs_daddr_t *);
38STATIC int
39xlog_clear_stale_blocks(
40 struct xlog *,
41 xfs_lsn_t);
42STATIC int
43xlog_do_recovery_pass(
44 struct xlog *, xfs_daddr_t, xfs_daddr_t, int, xfs_daddr_t *);
45
46/*
47 * Sector aligned buffer routines for buffer create/read/write/access
48 */
49
50/*
51 * Verify the log-relative block number and length in basic blocks are valid for
52 * an operation involving the given XFS log buffer. Returns true if the fields
53 * are valid, false otherwise.
54 */
55static inline bool
56xlog_verify_bno(
57 struct xlog *log,
58 xfs_daddr_t blk_no,
59 int bbcount)
60{
61 if (blk_no < 0 || blk_no >= log->l_logBBsize)
62 return false;
63 if (bbcount <= 0 || (blk_no + bbcount) > log->l_logBBsize)
64 return false;
65 return true;
66}
67
68/*
69 * Allocate a buffer to hold log data. The buffer needs to be able to map to
70 * a range of nbblks basic blocks at any valid offset within the log.
71 */
72static char *
73xlog_alloc_buffer(
74 struct xlog *log,
75 int nbblks)
76{
77 /*
78 * Pass log block 0 since we don't have an addr yet, buffer will be
79 * verified on read.
80 */
81 if (XFS_IS_CORRUPT(log->l_mp, !xlog_verify_bno(log, 0, nbblks))) {
82 xfs_warn(log->l_mp, "Invalid block length (0x%x) for buffer",
83 nbblks);
84 return NULL;
85 }
86
87 /*
88 * We do log I/O in units of log sectors (a power-of-2 multiple of the
89 * basic block size), so we round up the requested size to accommodate
90 * the basic blocks required for complete log sectors.
91 *
92 * In addition, the buffer may be used for a non-sector-aligned block
93 * offset, in which case an I/O of the requested size could extend
94 * beyond the end of the buffer. If the requested size is only 1 basic
95 * block it will never straddle a sector boundary, so this won't be an
96 * issue. Nor will this be a problem if the log I/O is done in basic
97 * blocks (sector size 1). But otherwise we extend the buffer by one
98 * extra log sector to ensure there's space to accommodate this
99 * possibility.
100 */
101 if (nbblks > 1 && log->l_sectBBsize > 1)
102 nbblks += log->l_sectBBsize;
103 nbblks = round_up(nbblks, log->l_sectBBsize);
104 return kvzalloc(size: BBTOB(nbblks), GFP_KERNEL | __GFP_RETRY_MAYFAIL);
105}
106
107/*
108 * Return the address of the start of the given block number's data
109 * in a log buffer. The buffer covers a log sector-aligned region.
110 */
111static inline unsigned int
112xlog_align(
113 struct xlog *log,
114 xfs_daddr_t blk_no)
115{
116 return BBTOB(blk_no & ((xfs_daddr_t)log->l_sectBBsize - 1));
117}
118
119static int
120xlog_do_io(
121 struct xlog *log,
122 xfs_daddr_t blk_no,
123 unsigned int nbblks,
124 char *data,
125 enum req_op op)
126{
127 int error;
128
129 if (XFS_IS_CORRUPT(log->l_mp, !xlog_verify_bno(log, blk_no, nbblks))) {
130 xfs_warn(log->l_mp,
131 "Invalid log block/length (0x%llx, 0x%x) for buffer",
132 blk_no, nbblks);
133 return -EFSCORRUPTED;
134 }
135
136 blk_no = round_down(blk_no, log->l_sectBBsize);
137 nbblks = round_up(nbblks, log->l_sectBBsize);
138 ASSERT(nbblks > 0);
139
140 error = xfs_rw_bdev(bdev: log->l_targ->bt_bdev, sector: log->l_logBBstart + blk_no,
141 count: BBTOB(nbblks), data, op);
142 if (error && !xlog_is_shutdown(log)) {
143 xfs_alert(log->l_mp,
144 "log recovery %s I/O error at daddr 0x%llx len %d error %d",
145 op == REQ_OP_WRITE ? "write" : "read",
146 blk_no, nbblks, error);
147 }
148 return error;
149}
150
151STATIC int
152xlog_bread_noalign(
153 struct xlog *log,
154 xfs_daddr_t blk_no,
155 int nbblks,
156 char *data)
157{
158 return xlog_do_io(log, blk_no, nbblks, data, op: REQ_OP_READ);
159}
160
161STATIC int
162xlog_bread(
163 struct xlog *log,
164 xfs_daddr_t blk_no,
165 int nbblks,
166 char *data,
167 char **offset)
168{
169 int error;
170
171 error = xlog_do_io(log, blk_no, nbblks, data, op: REQ_OP_READ);
172 if (!error)
173 *offset = data + xlog_align(log, blk_no);
174 return error;
175}
176
177STATIC int
178xlog_bwrite(
179 struct xlog *log,
180 xfs_daddr_t blk_no,
181 int nbblks,
182 char *data)
183{
184 return xlog_do_io(log, blk_no, nbblks, data, op: REQ_OP_WRITE);
185}
186
187#ifdef DEBUG
188/*
189 * dump debug superblock and log record information
190 */
191STATIC void
192xlog_header_check_dump(
193 xfs_mount_t *mp,
194 xlog_rec_header_t *head)
195{
196 xfs_debug(mp, "%s: SB : uuid = %pU, fmt = %d",
197 __func__, &mp->m_sb.sb_uuid, XLOG_FMT);
198 xfs_debug(mp, " log : uuid = %pU, fmt = %d",
199 &head->h_fs_uuid, be32_to_cpu(head->h_fmt));
200}
201#else
202#define xlog_header_check_dump(mp, head)
203#endif
204
205/*
206 * check log record header for recovery
207 */
208STATIC int
209xlog_header_check_recover(
210 xfs_mount_t *mp,
211 xlog_rec_header_t *head)
212{
213 ASSERT(head->h_magicno == cpu_to_be32(XLOG_HEADER_MAGIC_NUM));
214
215 /*
216 * IRIX doesn't write the h_fmt field and leaves it zeroed
217 * (XLOG_FMT_UNKNOWN). This stops us from trying to recover
218 * a dirty log created in IRIX.
219 */
220 if (XFS_IS_CORRUPT(mp, head->h_fmt != cpu_to_be32(XLOG_FMT))) {
221 xfs_warn(mp,
222 "dirty log written in incompatible format - can't recover");
223 xlog_header_check_dump(mp, head);
224 return -EFSCORRUPTED;
225 }
226 if (XFS_IS_CORRUPT(mp, !uuid_equal(&mp->m_sb.sb_uuid,
227 &head->h_fs_uuid))) {
228 xfs_warn(mp,
229 "dirty log entry has mismatched uuid - can't recover");
230 xlog_header_check_dump(mp, head);
231 return -EFSCORRUPTED;
232 }
233 return 0;
234}
235
236/*
237 * read the head block of the log and check the header
238 */
239STATIC int
240xlog_header_check_mount(
241 xfs_mount_t *mp,
242 xlog_rec_header_t *head)
243{
244 ASSERT(head->h_magicno == cpu_to_be32(XLOG_HEADER_MAGIC_NUM));
245
246 if (uuid_is_null(uuid: &head->h_fs_uuid)) {
247 /*
248 * IRIX doesn't write the h_fs_uuid or h_fmt fields. If
249 * h_fs_uuid is null, we assume this log was last mounted
250 * by IRIX and continue.
251 */
252 xfs_warn(mp, "null uuid in log - IRIX style log");
253 } else if (XFS_IS_CORRUPT(mp, !uuid_equal(&mp->m_sb.sb_uuid,
254 &head->h_fs_uuid))) {
255 xfs_warn(mp, "log has mismatched uuid - can't recover");
256 xlog_header_check_dump(mp, head);
257 return -EFSCORRUPTED;
258 }
259 return 0;
260}
261
262/*
263 * This routine finds (to an approximation) the first block in the physical
264 * log which contains the given cycle. It uses a binary search algorithm.
265 * Note that the algorithm can not be perfect because the disk will not
266 * necessarily be perfect.
267 */
268STATIC int
269xlog_find_cycle_start(
270 struct xlog *log,
271 char *buffer,
272 xfs_daddr_t first_blk,
273 xfs_daddr_t *last_blk,
274 uint cycle)
275{
276 char *offset;
277 xfs_daddr_t mid_blk;
278 xfs_daddr_t end_blk;
279 uint mid_cycle;
280 int error;
281
282 end_blk = *last_blk;
283 mid_blk = BLK_AVG(first_blk, end_blk);
284 while (mid_blk != first_blk && mid_blk != end_blk) {
285 error = xlog_bread(log, blk_no: mid_blk, nbblks: 1, data: buffer, offset: &offset);
286 if (error)
287 return error;
288 mid_cycle = xlog_get_cycle(offset);
289 if (mid_cycle == cycle)
290 end_blk = mid_blk; /* last_half_cycle == mid_cycle */
291 else
292 first_blk = mid_blk; /* first_half_cycle == mid_cycle */
293 mid_blk = BLK_AVG(first_blk, end_blk);
294 }
295 ASSERT((mid_blk == first_blk && mid_blk+1 == end_blk) ||
296 (mid_blk == end_blk && mid_blk-1 == first_blk));
297
298 *last_blk = end_blk;
299
300 return 0;
301}
302
303/*
304 * Check that a range of blocks does not contain stop_on_cycle_no.
305 * Fill in *new_blk with the block offset where such a block is
306 * found, or with -1 (an invalid block number) if there is no such
307 * block in the range. The scan needs to occur from front to back
308 * and the pointer into the region must be updated since a later
309 * routine will need to perform another test.
310 */
311STATIC int
312xlog_find_verify_cycle(
313 struct xlog *log,
314 xfs_daddr_t start_blk,
315 int nbblks,
316 uint stop_on_cycle_no,
317 xfs_daddr_t *new_blk)
318{
319 xfs_daddr_t i, j;
320 uint cycle;
321 char *buffer;
322 xfs_daddr_t bufblks;
323 char *buf = NULL;
324 int error = 0;
325
326 /*
327 * Greedily allocate a buffer big enough to handle the full
328 * range of basic blocks we'll be examining. If that fails,
329 * try a smaller size. We need to be able to read at least
330 * a log sector, or we're out of luck.
331 */
332 bufblks = roundup_pow_of_two(nbblks);
333 while (bufblks > log->l_logBBsize)
334 bufblks >>= 1;
335 while (!(buffer = xlog_alloc_buffer(log, nbblks: bufblks))) {
336 bufblks >>= 1;
337 if (bufblks < log->l_sectBBsize)
338 return -ENOMEM;
339 }
340
341 for (i = start_blk; i < start_blk + nbblks; i += bufblks) {
342 int bcount;
343
344 bcount = min(bufblks, (start_blk + nbblks - i));
345
346 error = xlog_bread(log, blk_no: i, nbblks: bcount, data: buffer, offset: &buf);
347 if (error)
348 goto out;
349
350 for (j = 0; j < bcount; j++) {
351 cycle = xlog_get_cycle(buf);
352 if (cycle == stop_on_cycle_no) {
353 *new_blk = i+j;
354 goto out;
355 }
356
357 buf += BBSIZE;
358 }
359 }
360
361 *new_blk = -1;
362
363out:
364 kmem_free(ptr: buffer);
365 return error;
366}
367
368static inline int
369xlog_logrec_hblks(struct xlog *log, struct xlog_rec_header *rh)
370{
371 if (xfs_has_logv2(mp: log->l_mp)) {
372 int h_size = be32_to_cpu(rh->h_size);
373
374 if ((be32_to_cpu(rh->h_version) & XLOG_VERSION_2) &&
375 h_size > XLOG_HEADER_CYCLE_SIZE)
376 return DIV_ROUND_UP(h_size, XLOG_HEADER_CYCLE_SIZE);
377 }
378 return 1;
379}
380
381/*
382 * Potentially backup over partial log record write.
383 *
384 * In the typical case, last_blk is the number of the block directly after
385 * a good log record. Therefore, we subtract one to get the block number
386 * of the last block in the given buffer. extra_bblks contains the number
387 * of blocks we would have read on a previous read. This happens when the
388 * last log record is split over the end of the physical log.
389 *
390 * extra_bblks is the number of blocks potentially verified on a previous
391 * call to this routine.
392 */
393STATIC int
394xlog_find_verify_log_record(
395 struct xlog *log,
396 xfs_daddr_t start_blk,
397 xfs_daddr_t *last_blk,
398 int extra_bblks)
399{
400 xfs_daddr_t i;
401 char *buffer;
402 char *offset = NULL;
403 xlog_rec_header_t *head = NULL;
404 int error = 0;
405 int smallmem = 0;
406 int num_blks = *last_blk - start_blk;
407 int xhdrs;
408
409 ASSERT(start_blk != 0 || *last_blk != start_blk);
410
411 buffer = xlog_alloc_buffer(log, nbblks: num_blks);
412 if (!buffer) {
413 buffer = xlog_alloc_buffer(log, nbblks: 1);
414 if (!buffer)
415 return -ENOMEM;
416 smallmem = 1;
417 } else {
418 error = xlog_bread(log, blk_no: start_blk, nbblks: num_blks, data: buffer, offset: &offset);
419 if (error)
420 goto out;
421 offset += ((num_blks - 1) << BBSHIFT);
422 }
423
424 for (i = (*last_blk) - 1; i >= 0; i--) {
425 if (i < start_blk) {
426 /* valid log record not found */
427 xfs_warn(log->l_mp,
428 "Log inconsistent (didn't find previous header)");
429 ASSERT(0);
430 error = -EFSCORRUPTED;
431 goto out;
432 }
433
434 if (smallmem) {
435 error = xlog_bread(log, blk_no: i, nbblks: 1, data: buffer, offset: &offset);
436 if (error)
437 goto out;
438 }
439
440 head = (xlog_rec_header_t *)offset;
441
442 if (head->h_magicno == cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
443 break;
444
445 if (!smallmem)
446 offset -= BBSIZE;
447 }
448
449 /*
450 * We hit the beginning of the physical log & still no header. Return
451 * to caller. If caller can handle a return of -1, then this routine
452 * will be called again for the end of the physical log.
453 */
454 if (i == -1) {
455 error = 1;
456 goto out;
457 }
458
459 /*
460 * We have the final block of the good log (the first block
461 * of the log record _before_ the head. So we check the uuid.
462 */
463 if ((error = xlog_header_check_mount(log->l_mp, head)))
464 goto out;
465
466 /*
467 * We may have found a log record header before we expected one.
468 * last_blk will be the 1st block # with a given cycle #. We may end
469 * up reading an entire log record. In this case, we don't want to
470 * reset last_blk. Only when last_blk points in the middle of a log
471 * record do we update last_blk.
472 */
473 xhdrs = xlog_logrec_hblks(log, head);
474
475 if (*last_blk - i + extra_bblks !=
476 BTOBB(be32_to_cpu(head->h_len)) + xhdrs)
477 *last_blk = i;
478
479out:
480 kmem_free(ptr: buffer);
481 return error;
482}
483
484/*
485 * Head is defined to be the point of the log where the next log write
486 * could go. This means that incomplete LR writes at the end are
487 * eliminated when calculating the head. We aren't guaranteed that previous
488 * LR have complete transactions. We only know that a cycle number of
489 * current cycle number -1 won't be present in the log if we start writing
490 * from our current block number.
491 *
492 * last_blk contains the block number of the first block with a given
493 * cycle number.
494 *
495 * Return: zero if normal, non-zero if error.
496 */
497STATIC int
498xlog_find_head(
499 struct xlog *log,
500 xfs_daddr_t *return_head_blk)
501{
502 char *buffer;
503 char *offset;
504 xfs_daddr_t new_blk, first_blk, start_blk, last_blk, head_blk;
505 int num_scan_bblks;
506 uint first_half_cycle, last_half_cycle;
507 uint stop_on_cycle;
508 int error, log_bbnum = log->l_logBBsize;
509
510 /* Is the end of the log device zeroed? */
511 error = xlog_find_zeroed(log, &first_blk);
512 if (error < 0) {
513 xfs_warn(log->l_mp, "empty log check failed");
514 return error;
515 }
516 if (error == 1) {
517 *return_head_blk = first_blk;
518
519 /* Is the whole lot zeroed? */
520 if (!first_blk) {
521 /* Linux XFS shouldn't generate totally zeroed logs -
522 * mkfs etc write a dummy unmount record to a fresh
523 * log so we can store the uuid in there
524 */
525 xfs_warn(log->l_mp, "totally zeroed log");
526 }
527
528 return 0;
529 }
530
531 first_blk = 0; /* get cycle # of 1st block */
532 buffer = xlog_alloc_buffer(log, nbblks: 1);
533 if (!buffer)
534 return -ENOMEM;
535
536 error = xlog_bread(log, blk_no: 0, nbblks: 1, data: buffer, offset: &offset);
537 if (error)
538 goto out_free_buffer;
539
540 first_half_cycle = xlog_get_cycle(offset);
541
542 last_blk = head_blk = log_bbnum - 1; /* get cycle # of last block */
543 error = xlog_bread(log, blk_no: last_blk, nbblks: 1, data: buffer, offset: &offset);
544 if (error)
545 goto out_free_buffer;
546
547 last_half_cycle = xlog_get_cycle(offset);
548 ASSERT(last_half_cycle != 0);
549
550 /*
551 * If the 1st half cycle number is equal to the last half cycle number,
552 * then the entire log is stamped with the same cycle number. In this
553 * case, head_blk can't be set to zero (which makes sense). The below
554 * math doesn't work out properly with head_blk equal to zero. Instead,
555 * we set it to log_bbnum which is an invalid block number, but this
556 * value makes the math correct. If head_blk doesn't changed through
557 * all the tests below, *head_blk is set to zero at the very end rather
558 * than log_bbnum. In a sense, log_bbnum and zero are the same block
559 * in a circular file.
560 */
561 if (first_half_cycle == last_half_cycle) {
562 /*
563 * In this case we believe that the entire log should have
564 * cycle number last_half_cycle. We need to scan backwards
565 * from the end verifying that there are no holes still
566 * containing last_half_cycle - 1. If we find such a hole,
567 * then the start of that hole will be the new head. The
568 * simple case looks like
569 * x | x ... | x - 1 | x
570 * Another case that fits this picture would be
571 * x | x + 1 | x ... | x
572 * In this case the head really is somewhere at the end of the
573 * log, as one of the latest writes at the beginning was
574 * incomplete.
575 * One more case is
576 * x | x + 1 | x ... | x - 1 | x
577 * This is really the combination of the above two cases, and
578 * the head has to end up at the start of the x-1 hole at the
579 * end of the log.
580 *
581 * In the 256k log case, we will read from the beginning to the
582 * end of the log and search for cycle numbers equal to x-1.
583 * We don't worry about the x+1 blocks that we encounter,
584 * because we know that they cannot be the head since the log
585 * started with x.
586 */
587 head_blk = log_bbnum;
588 stop_on_cycle = last_half_cycle - 1;
589 } else {
590 /*
591 * In this case we want to find the first block with cycle
592 * number matching last_half_cycle. We expect the log to be
593 * some variation on
594 * x + 1 ... | x ... | x
595 * The first block with cycle number x (last_half_cycle) will
596 * be where the new head belongs. First we do a binary search
597 * for the first occurrence of last_half_cycle. The binary
598 * search may not be totally accurate, so then we scan back
599 * from there looking for occurrences of last_half_cycle before
600 * us. If that backwards scan wraps around the beginning of
601 * the log, then we look for occurrences of last_half_cycle - 1
602 * at the end of the log. The cases we're looking for look
603 * like
604 * v binary search stopped here
605 * x + 1 ... | x | x + 1 | x ... | x
606 * ^ but we want to locate this spot
607 * or
608 * <---------> less than scan distance
609 * x + 1 ... | x ... | x - 1 | x
610 * ^ we want to locate this spot
611 */
612 stop_on_cycle = last_half_cycle;
613 error = xlog_find_cycle_start(log, buffer, first_blk, last_blk: &head_blk,
614 cycle: last_half_cycle);
615 if (error)
616 goto out_free_buffer;
617 }
618
619 /*
620 * Now validate the answer. Scan back some number of maximum possible
621 * blocks and make sure each one has the expected cycle number. The
622 * maximum is determined by the total possible amount of buffering
623 * in the in-core log. The following number can be made tighter if
624 * we actually look at the block size of the filesystem.
625 */
626 num_scan_bblks = min_t(int, log_bbnum, XLOG_TOTAL_REC_SHIFT(log));
627 if (head_blk >= num_scan_bblks) {
628 /*
629 * We are guaranteed that the entire check can be performed
630 * in one buffer.
631 */
632 start_blk = head_blk - num_scan_bblks;
633 if ((error = xlog_find_verify_cycle(log,
634 start_blk, nbblks: num_scan_bblks,
635 stop_on_cycle_no: stop_on_cycle, new_blk: &new_blk)))
636 goto out_free_buffer;
637 if (new_blk != -1)
638 head_blk = new_blk;
639 } else { /* need to read 2 parts of log */
640 /*
641 * We are going to scan backwards in the log in two parts.
642 * First we scan the physical end of the log. In this part
643 * of the log, we are looking for blocks with cycle number
644 * last_half_cycle - 1.
645 * If we find one, then we know that the log starts there, as
646 * we've found a hole that didn't get written in going around
647 * the end of the physical log. The simple case for this is
648 * x + 1 ... | x ... | x - 1 | x
649 * <---------> less than scan distance
650 * If all of the blocks at the end of the log have cycle number
651 * last_half_cycle, then we check the blocks at the start of
652 * the log looking for occurrences of last_half_cycle. If we
653 * find one, then our current estimate for the location of the
654 * first occurrence of last_half_cycle is wrong and we move
655 * back to the hole we've found. This case looks like
656 * x + 1 ... | x | x + 1 | x ...
657 * ^ binary search stopped here
658 * Another case we need to handle that only occurs in 256k
659 * logs is
660 * x + 1 ... | x ... | x+1 | x ...
661 * ^ binary search stops here
662 * In a 256k log, the scan at the end of the log will see the
663 * x + 1 blocks. We need to skip past those since that is
664 * certainly not the head of the log. By searching for
665 * last_half_cycle-1 we accomplish that.
666 */
667 ASSERT(head_blk <= INT_MAX &&
668 (xfs_daddr_t) num_scan_bblks >= head_blk);
669 start_blk = log_bbnum - (num_scan_bblks - head_blk);
670 if ((error = xlog_find_verify_cycle(log, start_blk,
671 nbblks: num_scan_bblks - (int)head_blk,
672 stop_on_cycle_no: (stop_on_cycle - 1), new_blk: &new_blk)))
673 goto out_free_buffer;
674 if (new_blk != -1) {
675 head_blk = new_blk;
676 goto validate_head;
677 }
678
679 /*
680 * Scan beginning of log now. The last part of the physical
681 * log is good. This scan needs to verify that it doesn't find
682 * the last_half_cycle.
683 */
684 start_blk = 0;
685 ASSERT(head_blk <= INT_MAX);
686 if ((error = xlog_find_verify_cycle(log,
687 start_blk, nbblks: (int)head_blk,
688 stop_on_cycle_no: stop_on_cycle, new_blk: &new_blk)))
689 goto out_free_buffer;
690 if (new_blk != -1)
691 head_blk = new_blk;
692 }
693
694validate_head:
695 /*
696 * Now we need to make sure head_blk is not pointing to a block in
697 * the middle of a log record.
698 */
699 num_scan_bblks = XLOG_REC_SHIFT(log);
700 if (head_blk >= num_scan_bblks) {
701 start_blk = head_blk - num_scan_bblks; /* don't read head_blk */
702
703 /* start ptr at last block ptr before head_blk */
704 error = xlog_find_verify_log_record(log, start_blk, last_blk: &head_blk, extra_bblks: 0);
705 if (error == 1)
706 error = -EIO;
707 if (error)
708 goto out_free_buffer;
709 } else {
710 start_blk = 0;
711 ASSERT(head_blk <= INT_MAX);
712 error = xlog_find_verify_log_record(log, start_blk, last_blk: &head_blk, extra_bblks: 0);
713 if (error < 0)
714 goto out_free_buffer;
715 if (error == 1) {
716 /* We hit the beginning of the log during our search */
717 start_blk = log_bbnum - (num_scan_bblks - head_blk);
718 new_blk = log_bbnum;
719 ASSERT(start_blk <= INT_MAX &&
720 (xfs_daddr_t) log_bbnum-start_blk >= 0);
721 ASSERT(head_blk <= INT_MAX);
722 error = xlog_find_verify_log_record(log, start_blk,
723 last_blk: &new_blk, extra_bblks: (int)head_blk);
724 if (error == 1)
725 error = -EIO;
726 if (error)
727 goto out_free_buffer;
728 if (new_blk != log_bbnum)
729 head_blk = new_blk;
730 } else if (error)
731 goto out_free_buffer;
732 }
733
734 kmem_free(ptr: buffer);
735 if (head_blk == log_bbnum)
736 *return_head_blk = 0;
737 else
738 *return_head_blk = head_blk;
739 /*
740 * When returning here, we have a good block number. Bad block
741 * means that during a previous crash, we didn't have a clean break
742 * from cycle number N to cycle number N-1. In this case, we need
743 * to find the first block with cycle number N-1.
744 */
745 return 0;
746
747out_free_buffer:
748 kmem_free(ptr: buffer);
749 if (error)
750 xfs_warn(log->l_mp, "failed to find log head");
751 return error;
752}
753
754/*
755 * Seek backwards in the log for log record headers.
756 *
757 * Given a starting log block, walk backwards until we find the provided number
758 * of records or hit the provided tail block. The return value is the number of
759 * records encountered or a negative error code. The log block and buffer
760 * pointer of the last record seen are returned in rblk and rhead respectively.
761 */
762STATIC int
763xlog_rseek_logrec_hdr(
764 struct xlog *log,
765 xfs_daddr_t head_blk,
766 xfs_daddr_t tail_blk,
767 int count,
768 char *buffer,
769 xfs_daddr_t *rblk,
770 struct xlog_rec_header **rhead,
771 bool *wrapped)
772{
773 int i;
774 int error;
775 int found = 0;
776 char *offset = NULL;
777 xfs_daddr_t end_blk;
778
779 *wrapped = false;
780
781 /*
782 * Walk backwards from the head block until we hit the tail or the first
783 * block in the log.
784 */
785 end_blk = head_blk > tail_blk ? tail_blk : 0;
786 for (i = (int) head_blk - 1; i >= end_blk; i--) {
787 error = xlog_bread(log, blk_no: i, nbblks: 1, data: buffer, offset: &offset);
788 if (error)
789 goto out_error;
790
791 if (*(__be32 *) offset == cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
792 *rblk = i;
793 *rhead = (struct xlog_rec_header *) offset;
794 if (++found == count)
795 break;
796 }
797 }
798
799 /*
800 * If we haven't hit the tail block or the log record header count,
801 * start looking again from the end of the physical log. Note that
802 * callers can pass head == tail if the tail is not yet known.
803 */
804 if (tail_blk >= head_blk && found != count) {
805 for (i = log->l_logBBsize - 1; i >= (int) tail_blk; i--) {
806 error = xlog_bread(log, blk_no: i, nbblks: 1, data: buffer, offset: &offset);
807 if (error)
808 goto out_error;
809
810 if (*(__be32 *)offset ==
811 cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
812 *wrapped = true;
813 *rblk = i;
814 *rhead = (struct xlog_rec_header *) offset;
815 if (++found == count)
816 break;
817 }
818 }
819 }
820
821 return found;
822
823out_error:
824 return error;
825}
826
827/*
828 * Seek forward in the log for log record headers.
829 *
830 * Given head and tail blocks, walk forward from the tail block until we find
831 * the provided number of records or hit the head block. The return value is the
832 * number of records encountered or a negative error code. The log block and
833 * buffer pointer of the last record seen are returned in rblk and rhead
834 * respectively.
835 */
836STATIC int
837xlog_seek_logrec_hdr(
838 struct xlog *log,
839 xfs_daddr_t head_blk,
840 xfs_daddr_t tail_blk,
841 int count,
842 char *buffer,
843 xfs_daddr_t *rblk,
844 struct xlog_rec_header **rhead,
845 bool *wrapped)
846{
847 int i;
848 int error;
849 int found = 0;
850 char *offset = NULL;
851 xfs_daddr_t end_blk;
852
853 *wrapped = false;
854
855 /*
856 * Walk forward from the tail block until we hit the head or the last
857 * block in the log.
858 */
859 end_blk = head_blk > tail_blk ? head_blk : log->l_logBBsize - 1;
860 for (i = (int) tail_blk; i <= end_blk; i++) {
861 error = xlog_bread(log, blk_no: i, nbblks: 1, data: buffer, offset: &offset);
862 if (error)
863 goto out_error;
864
865 if (*(__be32 *) offset == cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
866 *rblk = i;
867 *rhead = (struct xlog_rec_header *) offset;
868 if (++found == count)
869 break;
870 }
871 }
872
873 /*
874 * If we haven't hit the head block or the log record header count,
875 * start looking again from the start of the physical log.
876 */
877 if (tail_blk > head_blk && found != count) {
878 for (i = 0; i < (int) head_blk; i++) {
879 error = xlog_bread(log, blk_no: i, nbblks: 1, data: buffer, offset: &offset);
880 if (error)
881 goto out_error;
882
883 if (*(__be32 *)offset ==
884 cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
885 *wrapped = true;
886 *rblk = i;
887 *rhead = (struct xlog_rec_header *) offset;
888 if (++found == count)
889 break;
890 }
891 }
892 }
893
894 return found;
895
896out_error:
897 return error;
898}
899
900/*
901 * Calculate distance from head to tail (i.e., unused space in the log).
902 */
903static inline int
904xlog_tail_distance(
905 struct xlog *log,
906 xfs_daddr_t head_blk,
907 xfs_daddr_t tail_blk)
908{
909 if (head_blk < tail_blk)
910 return tail_blk - head_blk;
911
912 return tail_blk + (log->l_logBBsize - head_blk);
913}
914
915/*
916 * Verify the log tail. This is particularly important when torn or incomplete
917 * writes have been detected near the front of the log and the head has been
918 * walked back accordingly.
919 *
920 * We also have to handle the case where the tail was pinned and the head
921 * blocked behind the tail right before a crash. If the tail had been pushed
922 * immediately prior to the crash and the subsequent checkpoint was only
923 * partially written, it's possible it overwrote the last referenced tail in the
924 * log with garbage. This is not a coherency problem because the tail must have
925 * been pushed before it can be overwritten, but appears as log corruption to
926 * recovery because we have no way to know the tail was updated if the
927 * subsequent checkpoint didn't write successfully.
928 *
929 * Therefore, CRC check the log from tail to head. If a failure occurs and the
930 * offending record is within max iclog bufs from the head, walk the tail
931 * forward and retry until a valid tail is found or corruption is detected out
932 * of the range of a possible overwrite.
933 */
934STATIC int
935xlog_verify_tail(
936 struct xlog *log,
937 xfs_daddr_t head_blk,
938 xfs_daddr_t *tail_blk,
939 int hsize)
940{
941 struct xlog_rec_header *thead;
942 char *buffer;
943 xfs_daddr_t first_bad;
944 int error = 0;
945 bool wrapped;
946 xfs_daddr_t tmp_tail;
947 xfs_daddr_t orig_tail = *tail_blk;
948
949 buffer = xlog_alloc_buffer(log, nbblks: 1);
950 if (!buffer)
951 return -ENOMEM;
952
953 /*
954 * Make sure the tail points to a record (returns positive count on
955 * success).
956 */
957 error = xlog_seek_logrec_hdr(log, head_blk, tail_blk: *tail_blk, count: 1, buffer,
958 rblk: &tmp_tail, rhead: &thead, wrapped: &wrapped);
959 if (error < 0)
960 goto out;
961 if (*tail_blk != tmp_tail)
962 *tail_blk = tmp_tail;
963
964 /*
965 * Run a CRC check from the tail to the head. We can't just check
966 * MAX_ICLOGS records past the tail because the tail may point to stale
967 * blocks cleared during the search for the head/tail. These blocks are
968 * overwritten with zero-length records and thus record count is not a
969 * reliable indicator of the iclog state before a crash.
970 */
971 first_bad = 0;
972 error = xlog_do_recovery_pass(log, head_blk, *tail_blk,
973 XLOG_RECOVER_CRCPASS, &first_bad);
974 while ((error == -EFSBADCRC || error == -EFSCORRUPTED) && first_bad) {
975 int tail_distance;
976
977 /*
978 * Is corruption within range of the head? If so, retry from
979 * the next record. Otherwise return an error.
980 */
981 tail_distance = xlog_tail_distance(log, head_blk, tail_blk: first_bad);
982 if (tail_distance > BTOBB(XLOG_MAX_ICLOGS * hsize))
983 break;
984
985 /* skip to the next record; returns positive count on success */
986 error = xlog_seek_logrec_hdr(log, head_blk, tail_blk: first_bad, count: 2,
987 buffer, rblk: &tmp_tail, rhead: &thead, wrapped: &wrapped);
988 if (error < 0)
989 goto out;
990
991 *tail_blk = tmp_tail;
992 first_bad = 0;
993 error = xlog_do_recovery_pass(log, head_blk, *tail_blk,
994 XLOG_RECOVER_CRCPASS, &first_bad);
995 }
996
997 if (!error && *tail_blk != orig_tail)
998 xfs_warn(log->l_mp,
999 "Tail block (0x%llx) overwrite detected. Updated to 0x%llx",
1000 orig_tail, *tail_blk);
1001out:
1002 kmem_free(ptr: buffer);
1003 return error;
1004}
1005
1006/*
1007 * Detect and trim torn writes from the head of the log.
1008 *
1009 * Storage without sector atomicity guarantees can result in torn writes in the
1010 * log in the event of a crash. Our only means to detect this scenario is via
1011 * CRC verification. While we can't always be certain that CRC verification
1012 * failure is due to a torn write vs. an unrelated corruption, we do know that
1013 * only a certain number (XLOG_MAX_ICLOGS) of log records can be written out at
1014 * one time. Therefore, CRC verify up to XLOG_MAX_ICLOGS records at the head of
1015 * the log and treat failures in this range as torn writes as a matter of
1016 * policy. In the event of CRC failure, the head is walked back to the last good
1017 * record in the log and the tail is updated from that record and verified.
1018 */
1019STATIC int
1020xlog_verify_head(
1021 struct xlog *log,
1022 xfs_daddr_t *head_blk, /* in/out: unverified head */
1023 xfs_daddr_t *tail_blk, /* out: tail block */
1024 char *buffer,
1025 xfs_daddr_t *rhead_blk, /* start blk of last record */
1026 struct xlog_rec_header **rhead, /* ptr to last record */
1027 bool *wrapped) /* last rec. wraps phys. log */
1028{
1029 struct xlog_rec_header *tmp_rhead;
1030 char *tmp_buffer;
1031 xfs_daddr_t first_bad;
1032 xfs_daddr_t tmp_rhead_blk;
1033 int found;
1034 int error;
1035 bool tmp_wrapped;
1036
1037 /*
1038 * Check the head of the log for torn writes. Search backwards from the
1039 * head until we hit the tail or the maximum number of log record I/Os
1040 * that could have been in flight at one time. Use a temporary buffer so
1041 * we don't trash the rhead/buffer pointers from the caller.
1042 */
1043 tmp_buffer = xlog_alloc_buffer(log, nbblks: 1);
1044 if (!tmp_buffer)
1045 return -ENOMEM;
1046 error = xlog_rseek_logrec_hdr(log, *head_blk, *tail_blk,
1047 XLOG_MAX_ICLOGS, tmp_buffer,
1048 &tmp_rhead_blk, &tmp_rhead, &tmp_wrapped);
1049 kmem_free(ptr: tmp_buffer);
1050 if (error < 0)
1051 return error;
1052
1053 /*
1054 * Now run a CRC verification pass over the records starting at the
1055 * block found above to the current head. If a CRC failure occurs, the
1056 * log block of the first bad record is saved in first_bad.
1057 */
1058 error = xlog_do_recovery_pass(log, *head_blk, tmp_rhead_blk,
1059 XLOG_RECOVER_CRCPASS, &first_bad);
1060 if ((error == -EFSBADCRC || error == -EFSCORRUPTED) && first_bad) {
1061 /*
1062 * We've hit a potential torn write. Reset the error and warn
1063 * about it.
1064 */
1065 error = 0;
1066 xfs_warn(log->l_mp,
1067"Torn write (CRC failure) detected at log block 0x%llx. Truncating head block from 0x%llx.",
1068 first_bad, *head_blk);
1069
1070 /*
1071 * Get the header block and buffer pointer for the last good
1072 * record before the bad record.
1073 *
1074 * Note that xlog_find_tail() clears the blocks at the new head
1075 * (i.e., the records with invalid CRC) if the cycle number
1076 * matches the current cycle.
1077 */
1078 found = xlog_rseek_logrec_hdr(log, head_blk: first_bad, tail_blk: *tail_blk, count: 1,
1079 buffer, rblk: rhead_blk, rhead, wrapped);
1080 if (found < 0)
1081 return found;
1082 if (found == 0) /* XXX: right thing to do here? */
1083 return -EIO;
1084
1085 /*
1086 * Reset the head block to the starting block of the first bad
1087 * log record and set the tail block based on the last good
1088 * record.
1089 *
1090 * Bail out if the updated head/tail match as this indicates
1091 * possible corruption outside of the acceptable
1092 * (XLOG_MAX_ICLOGS) range. This is a job for xfs_repair...
1093 */
1094 *head_blk = first_bad;
1095 *tail_blk = BLOCK_LSN(be64_to_cpu((*rhead)->h_tail_lsn));
1096 if (*head_blk == *tail_blk) {
1097 ASSERT(0);
1098 return 0;
1099 }
1100 }
1101 if (error)
1102 return error;
1103
1104 return xlog_verify_tail(log, head_blk: *head_blk, tail_blk,
1105 be32_to_cpu((*rhead)->h_size));
1106}
1107
1108/*
1109 * We need to make sure we handle log wrapping properly, so we can't use the
1110 * calculated logbno directly. Make sure it wraps to the correct bno inside the
1111 * log.
1112 *
1113 * The log is limited to 32 bit sizes, so we use the appropriate modulus
1114 * operation here and cast it back to a 64 bit daddr on return.
1115 */
1116static inline xfs_daddr_t
1117xlog_wrap_logbno(
1118 struct xlog *log,
1119 xfs_daddr_t bno)
1120{
1121 int mod;
1122
1123 div_s64_rem(dividend: bno, divisor: log->l_logBBsize, remainder: &mod);
1124 return mod;
1125}
1126
1127/*
1128 * Check whether the head of the log points to an unmount record. In other
1129 * words, determine whether the log is clean. If so, update the in-core state
1130 * appropriately.
1131 */
1132static int
1133xlog_check_unmount_rec(
1134 struct xlog *log,
1135 xfs_daddr_t *head_blk,
1136 xfs_daddr_t *tail_blk,
1137 struct xlog_rec_header *rhead,
1138 xfs_daddr_t rhead_blk,
1139 char *buffer,
1140 bool *clean)
1141{
1142 struct xlog_op_header *op_head;
1143 xfs_daddr_t umount_data_blk;
1144 xfs_daddr_t after_umount_blk;
1145 int hblks;
1146 int error;
1147 char *offset;
1148
1149 *clean = false;
1150
1151 /*
1152 * Look for unmount record. If we find it, then we know there was a
1153 * clean unmount. Since 'i' could be the last block in the physical
1154 * log, we convert to a log block before comparing to the head_blk.
1155 *
1156 * Save the current tail lsn to use to pass to xlog_clear_stale_blocks()
1157 * below. We won't want to clear the unmount record if there is one, so
1158 * we pass the lsn of the unmount record rather than the block after it.
1159 */
1160 hblks = xlog_logrec_hblks(log, rh: rhead);
1161 after_umount_blk = xlog_wrap_logbno(log,
1162 bno: rhead_blk + hblks + BTOBB(be32_to_cpu(rhead->h_len)));
1163
1164 if (*head_blk == after_umount_blk &&
1165 be32_to_cpu(rhead->h_num_logops) == 1) {
1166 umount_data_blk = xlog_wrap_logbno(log, bno: rhead_blk + hblks);
1167 error = xlog_bread(log, blk_no: umount_data_blk, nbblks: 1, data: buffer, offset: &offset);
1168 if (error)
1169 return error;
1170
1171 op_head = (struct xlog_op_header *)offset;
1172 if (op_head->oh_flags & XLOG_UNMOUNT_TRANS) {
1173 /*
1174 * Set tail and last sync so that newly written log
1175 * records will point recovery to after the current
1176 * unmount record.
1177 */
1178 xlog_assign_atomic_lsn(lsn: &log->l_tail_lsn,
1179 cycle: log->l_curr_cycle, block: after_umount_blk);
1180 xlog_assign_atomic_lsn(lsn: &log->l_last_sync_lsn,
1181 cycle: log->l_curr_cycle, block: after_umount_blk);
1182 *tail_blk = after_umount_blk;
1183
1184 *clean = true;
1185 }
1186 }
1187
1188 return 0;
1189}
1190
1191static void
1192xlog_set_state(
1193 struct xlog *log,
1194 xfs_daddr_t head_blk,
1195 struct xlog_rec_header *rhead,
1196 xfs_daddr_t rhead_blk,
1197 bool bump_cycle)
1198{
1199 /*
1200 * Reset log values according to the state of the log when we
1201 * crashed. In the case where head_blk == 0, we bump curr_cycle
1202 * one because the next write starts a new cycle rather than
1203 * continuing the cycle of the last good log record. At this
1204 * point we have guaranteed that all partial log records have been
1205 * accounted for. Therefore, we know that the last good log record
1206 * written was complete and ended exactly on the end boundary
1207 * of the physical log.
1208 */
1209 log->l_prev_block = rhead_blk;
1210 log->l_curr_block = (int)head_blk;
1211 log->l_curr_cycle = be32_to_cpu(rhead->h_cycle);
1212 if (bump_cycle)
1213 log->l_curr_cycle++;
1214 atomic64_set(v: &log->l_tail_lsn, be64_to_cpu(rhead->h_tail_lsn));
1215 atomic64_set(v: &log->l_last_sync_lsn, be64_to_cpu(rhead->h_lsn));
1216 xlog_assign_grant_head(head: &log->l_reserve_head.grant, cycle: log->l_curr_cycle,
1217 space: BBTOB(log->l_curr_block));
1218 xlog_assign_grant_head(head: &log->l_write_head.grant, cycle: log->l_curr_cycle,
1219 space: BBTOB(log->l_curr_block));
1220}
1221
1222/*
1223 * Find the sync block number or the tail of the log.
1224 *
1225 * This will be the block number of the last record to have its
1226 * associated buffers synced to disk. Every log record header has
1227 * a sync lsn embedded in it. LSNs hold block numbers, so it is easy
1228 * to get a sync block number. The only concern is to figure out which
1229 * log record header to believe.
1230 *
1231 * The following algorithm uses the log record header with the largest
1232 * lsn. The entire log record does not need to be valid. We only care
1233 * that the header is valid.
1234 *
1235 * We could speed up search by using current head_blk buffer, but it is not
1236 * available.
1237 */
1238STATIC int
1239xlog_find_tail(
1240 struct xlog *log,
1241 xfs_daddr_t *head_blk,
1242 xfs_daddr_t *tail_blk)
1243{
1244 xlog_rec_header_t *rhead;
1245 char *offset = NULL;
1246 char *buffer;
1247 int error;
1248 xfs_daddr_t rhead_blk;
1249 xfs_lsn_t tail_lsn;
1250 bool wrapped = false;
1251 bool clean = false;
1252
1253 /*
1254 * Find previous log record
1255 */
1256 if ((error = xlog_find_head(log, return_head_blk: head_blk)))
1257 return error;
1258 ASSERT(*head_blk < INT_MAX);
1259
1260 buffer = xlog_alloc_buffer(log, nbblks: 1);
1261 if (!buffer)
1262 return -ENOMEM;
1263 if (*head_blk == 0) { /* special case */
1264 error = xlog_bread(log, blk_no: 0, nbblks: 1, data: buffer, offset: &offset);
1265 if (error)
1266 goto done;
1267
1268 if (xlog_get_cycle(offset) == 0) {
1269 *tail_blk = 0;
1270 /* leave all other log inited values alone */
1271 goto done;
1272 }
1273 }
1274
1275 /*
1276 * Search backwards through the log looking for the log record header
1277 * block. This wraps all the way back around to the head so something is
1278 * seriously wrong if we can't find it.
1279 */
1280 error = xlog_rseek_logrec_hdr(log, *head_blk, *head_blk, 1, buffer,
1281 &rhead_blk, &rhead, &wrapped);
1282 if (error < 0)
1283 goto done;
1284 if (!error) {
1285 xfs_warn(log->l_mp, "%s: couldn't find sync record", __func__);
1286 error = -EFSCORRUPTED;
1287 goto done;
1288 }
1289 *tail_blk = BLOCK_LSN(be64_to_cpu(rhead->h_tail_lsn));
1290
1291 /*
1292 * Set the log state based on the current head record.
1293 */
1294 xlog_set_state(log, *head_blk, rhead, rhead_blk, wrapped);
1295 tail_lsn = atomic64_read(&log->l_tail_lsn);
1296
1297 /*
1298 * Look for an unmount record at the head of the log. This sets the log
1299 * state to determine whether recovery is necessary.
1300 */
1301 error = xlog_check_unmount_rec(log, head_blk, tail_blk, rhead,
1302 rhead_blk, buffer, &clean);
1303 if (error)
1304 goto done;
1305
1306 /*
1307 * Verify the log head if the log is not clean (e.g., we have anything
1308 * but an unmount record at the head). This uses CRC verification to
1309 * detect and trim torn writes. If discovered, CRC failures are
1310 * considered torn writes and the log head is trimmed accordingly.
1311 *
1312 * Note that we can only run CRC verification when the log is dirty
1313 * because there's no guarantee that the log data behind an unmount
1314 * record is compatible with the current architecture.
1315 */
1316 if (!clean) {
1317 xfs_daddr_t orig_head = *head_blk;
1318
1319 error = xlog_verify_head(log, head_blk, tail_blk, buffer,
1320 &rhead_blk, &rhead, &wrapped);
1321 if (error)
1322 goto done;
1323
1324 /* update in-core state again if the head changed */
1325 if (*head_blk != orig_head) {
1326 xlog_set_state(log, *head_blk, rhead, rhead_blk,
1327 wrapped);
1328 tail_lsn = atomic64_read(&log->l_tail_lsn);
1329 error = xlog_check_unmount_rec(log, head_blk, tail_blk,
1330 rhead, rhead_blk, buffer,
1331 &clean);
1332 if (error)
1333 goto done;
1334 }
1335 }
1336
1337 /*
1338 * Note that the unmount was clean. If the unmount was not clean, we
1339 * need to know this to rebuild the superblock counters from the perag
1340 * headers if we have a filesystem using non-persistent counters.
1341 */
1342 if (clean)
1343 set_bit(XFS_OPSTATE_CLEAN, addr: &log->l_mp->m_opstate);
1344
1345 /*
1346 * Make sure that there are no blocks in front of the head
1347 * with the same cycle number as the head. This can happen
1348 * because we allow multiple outstanding log writes concurrently,
1349 * and the later writes might make it out before earlier ones.
1350 *
1351 * We use the lsn from before modifying it so that we'll never
1352 * overwrite the unmount record after a clean unmount.
1353 *
1354 * Do this only if we are going to recover the filesystem
1355 *
1356 * NOTE: This used to say "if (!readonly)"
1357 * However on Linux, we can & do recover a read-only filesystem.
1358 * We only skip recovery if NORECOVERY is specified on mount,
1359 * in which case we would not be here.
1360 *
1361 * But... if the -device- itself is readonly, just skip this.
1362 * We can't recover this device anyway, so it won't matter.
1363 */
1364 if (!xfs_readonly_buftarg(log->l_targ))
1365 error = xlog_clear_stale_blocks(log, tail_lsn);
1366
1367done:
1368 kmem_free(ptr: buffer);
1369
1370 if (error)
1371 xfs_warn(log->l_mp, "failed to locate log tail");
1372 return error;
1373}
1374
1375/*
1376 * Is the log zeroed at all?
1377 *
1378 * The last binary search should be changed to perform an X block read
1379 * once X becomes small enough. You can then search linearly through
1380 * the X blocks. This will cut down on the number of reads we need to do.
1381 *
1382 * If the log is partially zeroed, this routine will pass back the blkno
1383 * of the first block with cycle number 0. It won't have a complete LR
1384 * preceding it.
1385 *
1386 * Return:
1387 * 0 => the log is completely written to
1388 * 1 => use *blk_no as the first block of the log
1389 * <0 => error has occurred
1390 */
1391STATIC int
1392xlog_find_zeroed(
1393 struct xlog *log,
1394 xfs_daddr_t *blk_no)
1395{
1396 char *buffer;
1397 char *offset;
1398 uint first_cycle, last_cycle;
1399 xfs_daddr_t new_blk, last_blk, start_blk;
1400 xfs_daddr_t num_scan_bblks;
1401 int error, log_bbnum = log->l_logBBsize;
1402
1403 *blk_no = 0;
1404
1405 /* check totally zeroed log */
1406 buffer = xlog_alloc_buffer(log, nbblks: 1);
1407 if (!buffer)
1408 return -ENOMEM;
1409 error = xlog_bread(log, blk_no: 0, nbblks: 1, data: buffer, offset: &offset);
1410 if (error)
1411 goto out_free_buffer;
1412
1413 first_cycle = xlog_get_cycle(offset);
1414 if (first_cycle == 0) { /* completely zeroed log */
1415 *blk_no = 0;
1416 kmem_free(ptr: buffer);
1417 return 1;
1418 }
1419
1420 /* check partially zeroed log */
1421 error = xlog_bread(log, blk_no: log_bbnum-1, nbblks: 1, data: buffer, offset: &offset);
1422 if (error)
1423 goto out_free_buffer;
1424
1425 last_cycle = xlog_get_cycle(offset);
1426 if (last_cycle != 0) { /* log completely written to */
1427 kmem_free(ptr: buffer);
1428 return 0;
1429 }
1430
1431 /* we have a partially zeroed log */
1432 last_blk = log_bbnum-1;
1433 error = xlog_find_cycle_start(log, buffer, first_blk: 0, last_blk: &last_blk, cycle: 0);
1434 if (error)
1435 goto out_free_buffer;
1436
1437 /*
1438 * Validate the answer. Because there is no way to guarantee that
1439 * the entire log is made up of log records which are the same size,
1440 * we scan over the defined maximum blocks. At this point, the maximum
1441 * is not chosen to mean anything special. XXXmiken
1442 */
1443 num_scan_bblks = XLOG_TOTAL_REC_SHIFT(log);
1444 ASSERT(num_scan_bblks <= INT_MAX);
1445
1446 if (last_blk < num_scan_bblks)
1447 num_scan_bblks = last_blk;
1448 start_blk = last_blk - num_scan_bblks;
1449
1450 /*
1451 * We search for any instances of cycle number 0 that occur before
1452 * our current estimate of the head. What we're trying to detect is
1453 * 1 ... | 0 | 1 | 0...
1454 * ^ binary search ends here
1455 */
1456 if ((error = xlog_find_verify_cycle(log, start_blk,
1457 nbblks: (int)num_scan_bblks, stop_on_cycle_no: 0, new_blk: &new_blk)))
1458 goto out_free_buffer;
1459 if (new_blk != -1)
1460 last_blk = new_blk;
1461
1462 /*
1463 * Potentially backup over partial log record write. We don't need
1464 * to search the end of the log because we know it is zero.
1465 */
1466 error = xlog_find_verify_log_record(log, start_blk, last_blk: &last_blk, extra_bblks: 0);
1467 if (error == 1)
1468 error = -EIO;
1469 if (error)
1470 goto out_free_buffer;
1471
1472 *blk_no = last_blk;
1473out_free_buffer:
1474 kmem_free(ptr: buffer);
1475 if (error)
1476 return error;
1477 return 1;
1478}
1479
1480/*
1481 * These are simple subroutines used by xlog_clear_stale_blocks() below
1482 * to initialize a buffer full of empty log record headers and write
1483 * them into the log.
1484 */
1485STATIC void
1486xlog_add_record(
1487 struct xlog *log,
1488 char *buf,
1489 int cycle,
1490 int block,
1491 int tail_cycle,
1492 int tail_block)
1493{
1494 xlog_rec_header_t *recp = (xlog_rec_header_t *)buf;
1495
1496 memset(buf, 0, BBSIZE);
1497 recp->h_magicno = cpu_to_be32(XLOG_HEADER_MAGIC_NUM);
1498 recp->h_cycle = cpu_to_be32(cycle);
1499 recp->h_version = cpu_to_be32(
1500 xfs_has_logv2(log->l_mp) ? 2 : 1);
1501 recp->h_lsn = cpu_to_be64(xlog_assign_lsn(cycle, block));
1502 recp->h_tail_lsn = cpu_to_be64(xlog_assign_lsn(tail_cycle, tail_block));
1503 recp->h_fmt = cpu_to_be32(XLOG_FMT);
1504 memcpy(&recp->h_fs_uuid, &log->l_mp->m_sb.sb_uuid, sizeof(uuid_t));
1505}
1506
1507STATIC int
1508xlog_write_log_records(
1509 struct xlog *log,
1510 int cycle,
1511 int start_block,
1512 int blocks,
1513 int tail_cycle,
1514 int tail_block)
1515{
1516 char *offset;
1517 char *buffer;
1518 int balign, ealign;
1519 int sectbb = log->l_sectBBsize;
1520 int end_block = start_block + blocks;
1521 int bufblks;
1522 int error = 0;
1523 int i, j = 0;
1524
1525 /*
1526 * Greedily allocate a buffer big enough to handle the full
1527 * range of basic blocks to be written. If that fails, try
1528 * a smaller size. We need to be able to write at least a
1529 * log sector, or we're out of luck.
1530 */
1531 bufblks = roundup_pow_of_two(blocks);
1532 while (bufblks > log->l_logBBsize)
1533 bufblks >>= 1;
1534 while (!(buffer = xlog_alloc_buffer(log, nbblks: bufblks))) {
1535 bufblks >>= 1;
1536 if (bufblks < sectbb)
1537 return -ENOMEM;
1538 }
1539
1540 /* We may need to do a read at the start to fill in part of
1541 * the buffer in the starting sector not covered by the first
1542 * write below.
1543 */
1544 balign = round_down(start_block, sectbb);
1545 if (balign != start_block) {
1546 error = xlog_bread_noalign(log, blk_no: start_block, nbblks: 1, data: buffer);
1547 if (error)
1548 goto out_free_buffer;
1549
1550 j = start_block - balign;
1551 }
1552
1553 for (i = start_block; i < end_block; i += bufblks) {
1554 int bcount, endcount;
1555
1556 bcount = min(bufblks, end_block - start_block);
1557 endcount = bcount - j;
1558
1559 /* We may need to do a read at the end to fill in part of
1560 * the buffer in the final sector not covered by the write.
1561 * If this is the same sector as the above read, skip it.
1562 */
1563 ealign = round_down(end_block, sectbb);
1564 if (j == 0 && (start_block + endcount > ealign)) {
1565 error = xlog_bread_noalign(log, blk_no: ealign, nbblks: sectbb,
1566 data: buffer + BBTOB(ealign - start_block));
1567 if (error)
1568 break;
1569
1570 }
1571
1572 offset = buffer + xlog_align(log, blk_no: start_block);
1573 for (; j < endcount; j++) {
1574 xlog_add_record(log, buf: offset, cycle, block: i+j,
1575 tail_cycle, tail_block);
1576 offset += BBSIZE;
1577 }
1578 error = xlog_bwrite(log, blk_no: start_block, nbblks: endcount, data: buffer);
1579 if (error)
1580 break;
1581 start_block += endcount;
1582 j = 0;
1583 }
1584
1585out_free_buffer:
1586 kmem_free(ptr: buffer);
1587 return error;
1588}
1589
1590/*
1591 * This routine is called to blow away any incomplete log writes out
1592 * in front of the log head. We do this so that we won't become confused
1593 * if we come up, write only a little bit more, and then crash again.
1594 * If we leave the partial log records out there, this situation could
1595 * cause us to think those partial writes are valid blocks since they
1596 * have the current cycle number. We get rid of them by overwriting them
1597 * with empty log records with the old cycle number rather than the
1598 * current one.
1599 *
1600 * The tail lsn is passed in rather than taken from
1601 * the log so that we will not write over the unmount record after a
1602 * clean unmount in a 512 block log. Doing so would leave the log without
1603 * any valid log records in it until a new one was written. If we crashed
1604 * during that time we would not be able to recover.
1605 */
1606STATIC int
1607xlog_clear_stale_blocks(
1608 struct xlog *log,
1609 xfs_lsn_t tail_lsn)
1610{
1611 int tail_cycle, head_cycle;
1612 int tail_block, head_block;
1613 int tail_distance, max_distance;
1614 int distance;
1615 int error;
1616
1617 tail_cycle = CYCLE_LSN(tail_lsn);
1618 tail_block = BLOCK_LSN(tail_lsn);
1619 head_cycle = log->l_curr_cycle;
1620 head_block = log->l_curr_block;
1621
1622 /*
1623 * Figure out the distance between the new head of the log
1624 * and the tail. We want to write over any blocks beyond the
1625 * head that we may have written just before the crash, but
1626 * we don't want to overwrite the tail of the log.
1627 */
1628 if (head_cycle == tail_cycle) {
1629 /*
1630 * The tail is behind the head in the physical log,
1631 * so the distance from the head to the tail is the
1632 * distance from the head to the end of the log plus
1633 * the distance from the beginning of the log to the
1634 * tail.
1635 */
1636 if (XFS_IS_CORRUPT(log->l_mp,
1637 head_block < tail_block ||
1638 head_block >= log->l_logBBsize))
1639 return -EFSCORRUPTED;
1640 tail_distance = tail_block + (log->l_logBBsize - head_block);
1641 } else {
1642 /*
1643 * The head is behind the tail in the physical log,
1644 * so the distance from the head to the tail is just
1645 * the tail block minus the head block.
1646 */
1647 if (XFS_IS_CORRUPT(log->l_mp,
1648 head_block >= tail_block ||
1649 head_cycle != tail_cycle + 1))
1650 return -EFSCORRUPTED;
1651 tail_distance = tail_block - head_block;
1652 }
1653
1654 /*
1655 * If the head is right up against the tail, we can't clear
1656 * anything.
1657 */
1658 if (tail_distance <= 0) {
1659 ASSERT(tail_distance == 0);
1660 return 0;
1661 }
1662
1663 max_distance = XLOG_TOTAL_REC_SHIFT(log);
1664 /*
1665 * Take the smaller of the maximum amount of outstanding I/O
1666 * we could have and the distance to the tail to clear out.
1667 * We take the smaller so that we don't overwrite the tail and
1668 * we don't waste all day writing from the head to the tail
1669 * for no reason.
1670 */
1671 max_distance = min(max_distance, tail_distance);
1672
1673 if ((head_block + max_distance) <= log->l_logBBsize) {
1674 /*
1675 * We can stomp all the blocks we need to without
1676 * wrapping around the end of the log. Just do it
1677 * in a single write. Use the cycle number of the
1678 * current cycle minus one so that the log will look like:
1679 * n ... | n - 1 ...
1680 */
1681 error = xlog_write_log_records(log, cycle: (head_cycle - 1),
1682 start_block: head_block, blocks: max_distance, tail_cycle,
1683 tail_block);
1684 if (error)
1685 return error;
1686 } else {
1687 /*
1688 * We need to wrap around the end of the physical log in
1689 * order to clear all the blocks. Do it in two separate
1690 * I/Os. The first write should be from the head to the
1691 * end of the physical log, and it should use the current
1692 * cycle number minus one just like above.
1693 */
1694 distance = log->l_logBBsize - head_block;
1695 error = xlog_write_log_records(log, cycle: (head_cycle - 1),
1696 start_block: head_block, blocks: distance, tail_cycle,
1697 tail_block);
1698
1699 if (error)
1700 return error;
1701
1702 /*
1703 * Now write the blocks at the start of the physical log.
1704 * This writes the remainder of the blocks we want to clear.
1705 * It uses the current cycle number since we're now on the
1706 * same cycle as the head so that we get:
1707 * n ... n ... | n - 1 ...
1708 * ^^^^^ blocks we're writing
1709 */
1710 distance = max_distance - (log->l_logBBsize - head_block);
1711 error = xlog_write_log_records(log, cycle: head_cycle, start_block: 0, blocks: distance,
1712 tail_cycle, tail_block);
1713 if (error)
1714 return error;
1715 }
1716
1717 return 0;
1718}
1719
1720/*
1721 * Release the recovered intent item in the AIL that matches the given intent
1722 * type and intent id.
1723 */
1724void
1725xlog_recover_release_intent(
1726 struct xlog *log,
1727 unsigned short intent_type,
1728 uint64_t intent_id)
1729{
1730 struct xfs_ail_cursor cur;
1731 struct xfs_log_item *lip;
1732 struct xfs_ail *ailp = log->l_ailp;
1733
1734 spin_lock(lock: &ailp->ail_lock);
1735 for (lip = xfs_trans_ail_cursor_first(ailp, &cur, 0); lip != NULL;
1736 lip = xfs_trans_ail_cursor_next(ailp, cur: &cur)) {
1737 if (lip->li_type != intent_type)
1738 continue;
1739 if (!lip->li_ops->iop_match(lip, intent_id))
1740 continue;
1741
1742 spin_unlock(lock: &ailp->ail_lock);
1743 lip->li_ops->iop_release(lip);
1744 spin_lock(lock: &ailp->ail_lock);
1745 break;
1746 }
1747
1748 xfs_trans_ail_cursor_done(cur: &cur);
1749 spin_unlock(lock: &ailp->ail_lock);
1750}
1751
1752int
1753xlog_recover_iget(
1754 struct xfs_mount *mp,
1755 xfs_ino_t ino,
1756 struct xfs_inode **ipp)
1757{
1758 int error;
1759
1760 error = xfs_iget(mp, NULL, ino, flags: 0, lock_flags: 0, ipp);
1761 if (error)
1762 return error;
1763
1764 error = xfs_qm_dqattach(*ipp);
1765 if (error) {
1766 xfs_irele(ip: *ipp);
1767 return error;
1768 }
1769
1770 if (VFS_I(ip: *ipp)->i_nlink == 0)
1771 xfs_iflags_set(ip: *ipp, XFS_IRECOVERY);
1772
1773 return 0;
1774}
1775
1776/******************************************************************************
1777 *
1778 * Log recover routines
1779 *
1780 ******************************************************************************
1781 */
1782static const struct xlog_recover_item_ops *xlog_recover_item_ops[] = {
1783 &xlog_buf_item_ops,
1784 &xlog_inode_item_ops,
1785 &xlog_dquot_item_ops,
1786 &xlog_quotaoff_item_ops,
1787 &xlog_icreate_item_ops,
1788 &xlog_efi_item_ops,
1789 &xlog_efd_item_ops,
1790 &xlog_rui_item_ops,
1791 &xlog_rud_item_ops,
1792 &xlog_cui_item_ops,
1793 &xlog_cud_item_ops,
1794 &xlog_bui_item_ops,
1795 &xlog_bud_item_ops,
1796 &xlog_attri_item_ops,
1797 &xlog_attrd_item_ops,
1798};
1799
1800static const struct xlog_recover_item_ops *
1801xlog_find_item_ops(
1802 struct xlog_recover_item *item)
1803{
1804 unsigned int i;
1805
1806 for (i = 0; i < ARRAY_SIZE(xlog_recover_item_ops); i++)
1807 if (ITEM_TYPE(item) == xlog_recover_item_ops[i]->item_type)
1808 return xlog_recover_item_ops[i];
1809
1810 return NULL;
1811}
1812
1813/*
1814 * Sort the log items in the transaction.
1815 *
1816 * The ordering constraints are defined by the inode allocation and unlink
1817 * behaviour. The rules are:
1818 *
1819 * 1. Every item is only logged once in a given transaction. Hence it
1820 * represents the last logged state of the item. Hence ordering is
1821 * dependent on the order in which operations need to be performed so
1822 * required initial conditions are always met.
1823 *
1824 * 2. Cancelled buffers are recorded in pass 1 in a separate table and
1825 * there's nothing to replay from them so we can simply cull them
1826 * from the transaction. However, we can't do that until after we've
1827 * replayed all the other items because they may be dependent on the
1828 * cancelled buffer and replaying the cancelled buffer can remove it
1829 * form the cancelled buffer table. Hence they have tobe done last.
1830 *
1831 * 3. Inode allocation buffers must be replayed before inode items that
1832 * read the buffer and replay changes into it. For filesystems using the
1833 * ICREATE transactions, this means XFS_LI_ICREATE objects need to get
1834 * treated the same as inode allocation buffers as they create and
1835 * initialise the buffers directly.
1836 *
1837 * 4. Inode unlink buffers must be replayed after inode items are replayed.
1838 * This ensures that inodes are completely flushed to the inode buffer
1839 * in a "free" state before we remove the unlinked inode list pointer.
1840 *
1841 * Hence the ordering needs to be inode allocation buffers first, inode items
1842 * second, inode unlink buffers third and cancelled buffers last.
1843 *
1844 * But there's a problem with that - we can't tell an inode allocation buffer
1845 * apart from a regular buffer, so we can't separate them. We can, however,
1846 * tell an inode unlink buffer from the others, and so we can separate them out
1847 * from all the other buffers and move them to last.
1848 *
1849 * Hence, 4 lists, in order from head to tail:
1850 * - buffer_list for all buffers except cancelled/inode unlink buffers
1851 * - item_list for all non-buffer items
1852 * - inode_buffer_list for inode unlink buffers
1853 * - cancel_list for the cancelled buffers
1854 *
1855 * Note that we add objects to the tail of the lists so that first-to-last
1856 * ordering is preserved within the lists. Adding objects to the head of the
1857 * list means when we traverse from the head we walk them in last-to-first
1858 * order. For cancelled buffers and inode unlink buffers this doesn't matter,
1859 * but for all other items there may be specific ordering that we need to
1860 * preserve.
1861 */
1862STATIC int
1863xlog_recover_reorder_trans(
1864 struct xlog *log,
1865 struct xlog_recover *trans,
1866 int pass)
1867{
1868 struct xlog_recover_item *item, *n;
1869 int error = 0;
1870 LIST_HEAD(sort_list);
1871 LIST_HEAD(cancel_list);
1872 LIST_HEAD(buffer_list);
1873 LIST_HEAD(inode_buffer_list);
1874 LIST_HEAD(item_list);
1875
1876 list_splice_init(list: &trans->r_itemq, head: &sort_list);
1877 list_for_each_entry_safe(item, n, &sort_list, ri_list) {
1878 enum xlog_recover_reorder fate = XLOG_REORDER_ITEM_LIST;
1879
1880 item->ri_ops = xlog_find_item_ops(item);
1881 if (!item->ri_ops) {
1882 xfs_warn(log->l_mp,
1883 "%s: unrecognized type of log operation (%d)",
1884 __func__, ITEM_TYPE(item));
1885 ASSERT(0);
1886 /*
1887 * return the remaining items back to the transaction
1888 * item list so they can be freed in caller.
1889 */
1890 if (!list_empty(head: &sort_list))
1891 list_splice_init(list: &sort_list, head: &trans->r_itemq);
1892 error = -EFSCORRUPTED;
1893 break;
1894 }
1895
1896 if (item->ri_ops->reorder)
1897 fate = item->ri_ops->reorder(item);
1898
1899 switch (fate) {
1900 case XLOG_REORDER_BUFFER_LIST:
1901 list_move_tail(list: &item->ri_list, head: &buffer_list);
1902 break;
1903 case XLOG_REORDER_CANCEL_LIST:
1904 trace_xfs_log_recover_item_reorder_head(log,
1905 trans, item, pass);
1906 list_move(list: &item->ri_list, head: &cancel_list);
1907 break;
1908 case XLOG_REORDER_INODE_BUFFER_LIST:
1909 list_move(list: &item->ri_list, head: &inode_buffer_list);
1910 break;
1911 case XLOG_REORDER_ITEM_LIST:
1912 trace_xfs_log_recover_item_reorder_tail(log,
1913 trans, item, pass);
1914 list_move_tail(list: &item->ri_list, head: &item_list);
1915 break;
1916 }
1917 }
1918
1919 ASSERT(list_empty(&sort_list));
1920 if (!list_empty(head: &buffer_list))
1921 list_splice(list: &buffer_list, head: &trans->r_itemq);
1922 if (!list_empty(head: &item_list))
1923 list_splice_tail(list: &item_list, head: &trans->r_itemq);
1924 if (!list_empty(head: &inode_buffer_list))
1925 list_splice_tail(list: &inode_buffer_list, head: &trans->r_itemq);
1926 if (!list_empty(head: &cancel_list))
1927 list_splice_tail(list: &cancel_list, head: &trans->r_itemq);
1928 return error;
1929}
1930
1931void
1932xlog_buf_readahead(
1933 struct xlog *log,
1934 xfs_daddr_t blkno,
1935 uint len,
1936 const struct xfs_buf_ops *ops)
1937{
1938 if (!xlog_is_buffer_cancelled(log, blkno, len))
1939 xfs_buf_readahead(target: log->l_mp->m_ddev_targp, blkno, numblks: len, ops);
1940}
1941
1942STATIC int
1943xlog_recover_items_pass2(
1944 struct xlog *log,
1945 struct xlog_recover *trans,
1946 struct list_head *buffer_list,
1947 struct list_head *item_list)
1948{
1949 struct xlog_recover_item *item;
1950 int error = 0;
1951
1952 list_for_each_entry(item, item_list, ri_list) {
1953 trace_xfs_log_recover_item_recover(log, trans, item,
1954 XLOG_RECOVER_PASS2);
1955
1956 if (item->ri_ops->commit_pass2)
1957 error = item->ri_ops->commit_pass2(log, buffer_list,
1958 item, trans->r_lsn);
1959 if (error)
1960 return error;
1961 }
1962
1963 return error;
1964}
1965
1966/*
1967 * Perform the transaction.
1968 *
1969 * If the transaction modifies a buffer or inode, do it now. Otherwise,
1970 * EFIs and EFDs get queued up by adding entries into the AIL for them.
1971 */
1972STATIC int
1973xlog_recover_commit_trans(
1974 struct xlog *log,
1975 struct xlog_recover *trans,
1976 int pass,
1977 struct list_head *buffer_list)
1978{
1979 int error = 0;
1980 int items_queued = 0;
1981 struct xlog_recover_item *item;
1982 struct xlog_recover_item *next;
1983 LIST_HEAD (ra_list);
1984 LIST_HEAD (done_list);
1985
1986 #define XLOG_RECOVER_COMMIT_QUEUE_MAX 100
1987
1988 hlist_del_init(n: &trans->r_list);
1989
1990 error = xlog_recover_reorder_trans(log, trans, pass);
1991 if (error)
1992 return error;
1993
1994 list_for_each_entry_safe(item, next, &trans->r_itemq, ri_list) {
1995 trace_xfs_log_recover_item_recover(log, trans, item, pass);
1996
1997 switch (pass) {
1998 case XLOG_RECOVER_PASS1:
1999 if (item->ri_ops->commit_pass1)
2000 error = item->ri_ops->commit_pass1(log, item);
2001 break;
2002 case XLOG_RECOVER_PASS2:
2003 if (item->ri_ops->ra_pass2)
2004 item->ri_ops->ra_pass2(log, item);
2005 list_move_tail(list: &item->ri_list, head: &ra_list);
2006 items_queued++;
2007 if (items_queued >= XLOG_RECOVER_COMMIT_QUEUE_MAX) {
2008 error = xlog_recover_items_pass2(log, trans,
2009 buffer_list, item_list: &ra_list);
2010 list_splice_tail_init(list: &ra_list, head: &done_list);
2011 items_queued = 0;
2012 }
2013
2014 break;
2015 default:
2016 ASSERT(0);
2017 }
2018
2019 if (error)
2020 goto out;
2021 }
2022
2023out:
2024 if (!list_empty(head: &ra_list)) {
2025 if (!error)
2026 error = xlog_recover_items_pass2(log, trans,
2027 buffer_list, item_list: &ra_list);
2028 list_splice_tail_init(list: &ra_list, head: &done_list);
2029 }
2030
2031 if (!list_empty(head: &done_list))
2032 list_splice_init(list: &done_list, head: &trans->r_itemq);
2033
2034 return error;
2035}
2036
2037STATIC void
2038xlog_recover_add_item(
2039 struct list_head *head)
2040{
2041 struct xlog_recover_item *item;
2042
2043 item = kmem_zalloc(sizeof(struct xlog_recover_item), 0);
2044 INIT_LIST_HEAD(list: &item->ri_list);
2045 list_add_tail(new: &item->ri_list, head);
2046}
2047
2048STATIC int
2049xlog_recover_add_to_cont_trans(
2050 struct xlog *log,
2051 struct xlog_recover *trans,
2052 char *dp,
2053 int len)
2054{
2055 struct xlog_recover_item *item;
2056 char *ptr, *old_ptr;
2057 int old_len;
2058
2059 /*
2060 * If the transaction is empty, the header was split across this and the
2061 * previous record. Copy the rest of the header.
2062 */
2063 if (list_empty(head: &trans->r_itemq)) {
2064 ASSERT(len <= sizeof(struct xfs_trans_header));
2065 if (len > sizeof(struct xfs_trans_header)) {
2066 xfs_warn(log->l_mp, "%s: bad header length", __func__);
2067 return -EFSCORRUPTED;
2068 }
2069
2070 xlog_recover_add_item(head: &trans->r_itemq);
2071 ptr = (char *)&trans->r_theader +
2072 sizeof(struct xfs_trans_header) - len;
2073 memcpy(ptr, dp, len);
2074 return 0;
2075 }
2076
2077 /* take the tail entry */
2078 item = list_entry(trans->r_itemq.prev, struct xlog_recover_item,
2079 ri_list);
2080
2081 old_ptr = item->ri_buf[item->ri_cnt-1].i_addr;
2082 old_len = item->ri_buf[item->ri_cnt-1].i_len;
2083
2084 ptr = kvrealloc(p: old_ptr, oldsize: old_len, newsize: len + old_len, GFP_KERNEL);
2085 if (!ptr)
2086 return -ENOMEM;
2087 memcpy(&ptr[old_len], dp, len);
2088 item->ri_buf[item->ri_cnt-1].i_len += len;
2089 item->ri_buf[item->ri_cnt-1].i_addr = ptr;
2090 trace_xfs_log_recover_item_add_cont(log, trans, item, pass: 0);
2091 return 0;
2092}
2093
2094/*
2095 * The next region to add is the start of a new region. It could be
2096 * a whole region or it could be the first part of a new region. Because
2097 * of this, the assumption here is that the type and size fields of all
2098 * format structures fit into the first 32 bits of the structure.
2099 *
2100 * This works because all regions must be 32 bit aligned. Therefore, we
2101 * either have both fields or we have neither field. In the case we have
2102 * neither field, the data part of the region is zero length. We only have
2103 * a log_op_header and can throw away the header since a new one will appear
2104 * later. If we have at least 4 bytes, then we can determine how many regions
2105 * will appear in the current log item.
2106 */
2107STATIC int
2108xlog_recover_add_to_trans(
2109 struct xlog *log,
2110 struct xlog_recover *trans,
2111 char *dp,
2112 int len)
2113{
2114 struct xfs_inode_log_format *in_f; /* any will do */
2115 struct xlog_recover_item *item;
2116 char *ptr;
2117
2118 if (!len)
2119 return 0;
2120 if (list_empty(head: &trans->r_itemq)) {
2121 /* we need to catch log corruptions here */
2122 if (*(uint *)dp != XFS_TRANS_HEADER_MAGIC) {
2123 xfs_warn(log->l_mp, "%s: bad header magic number",
2124 __func__);
2125 ASSERT(0);
2126 return -EFSCORRUPTED;
2127 }
2128
2129 if (len > sizeof(struct xfs_trans_header)) {
2130 xfs_warn(log->l_mp, "%s: bad header length", __func__);
2131 ASSERT(0);
2132 return -EFSCORRUPTED;
2133 }
2134
2135 /*
2136 * The transaction header can be arbitrarily split across op
2137 * records. If we don't have the whole thing here, copy what we
2138 * do have and handle the rest in the next record.
2139 */
2140 if (len == sizeof(struct xfs_trans_header))
2141 xlog_recover_add_item(head: &trans->r_itemq);
2142 memcpy(&trans->r_theader, dp, len);
2143 return 0;
2144 }
2145
2146 ptr = kmem_alloc(len, 0);
2147 memcpy(ptr, dp, len);
2148 in_f = (struct xfs_inode_log_format *)ptr;
2149
2150 /* take the tail entry */
2151 item = list_entry(trans->r_itemq.prev, struct xlog_recover_item,
2152 ri_list);
2153 if (item->ri_total != 0 &&
2154 item->ri_total == item->ri_cnt) {
2155 /* tail item is in use, get a new one */
2156 xlog_recover_add_item(head: &trans->r_itemq);
2157 item = list_entry(trans->r_itemq.prev,
2158 struct xlog_recover_item, ri_list);
2159 }
2160
2161 if (item->ri_total == 0) { /* first region to be added */
2162 if (in_f->ilf_size == 0 ||
2163 in_f->ilf_size > XLOG_MAX_REGIONS_IN_ITEM) {
2164 xfs_warn(log->l_mp,
2165 "bad number of regions (%d) in inode log format",
2166 in_f->ilf_size);
2167 ASSERT(0);
2168 kmem_free(ptr);
2169 return -EFSCORRUPTED;
2170 }
2171
2172 item->ri_total = in_f->ilf_size;
2173 item->ri_buf =
2174 kmem_zalloc(item->ri_total * sizeof(xfs_log_iovec_t),
2175 0);
2176 }
2177
2178 if (item->ri_total <= item->ri_cnt) {
2179 xfs_warn(log->l_mp,
2180 "log item region count (%d) overflowed size (%d)",
2181 item->ri_cnt, item->ri_total);
2182 ASSERT(0);
2183 kmem_free(ptr);
2184 return -EFSCORRUPTED;
2185 }
2186
2187 /* Description region is ri_buf[0] */
2188 item->ri_buf[item->ri_cnt].i_addr = ptr;
2189 item->ri_buf[item->ri_cnt].i_len = len;
2190 item->ri_cnt++;
2191 trace_xfs_log_recover_item_add(log, trans, item, pass: 0);
2192 return 0;
2193}
2194
2195/*
2196 * Free up any resources allocated by the transaction
2197 *
2198 * Remember that EFIs, EFDs, and IUNLINKs are handled later.
2199 */
2200STATIC void
2201xlog_recover_free_trans(
2202 struct xlog_recover *trans)
2203{
2204 struct xlog_recover_item *item, *n;
2205 int i;
2206
2207 hlist_del_init(n: &trans->r_list);
2208
2209 list_for_each_entry_safe(item, n, &trans->r_itemq, ri_list) {
2210 /* Free the regions in the item. */
2211 list_del(entry: &item->ri_list);
2212 for (i = 0; i < item->ri_cnt; i++)
2213 kmem_free(ptr: item->ri_buf[i].i_addr);
2214 /* Free the item itself */
2215 kmem_free(ptr: item->ri_buf);
2216 kmem_free(ptr: item);
2217 }
2218 /* Free the transaction recover structure */
2219 kmem_free(ptr: trans);
2220}
2221
2222/*
2223 * On error or completion, trans is freed.
2224 */
2225STATIC int
2226xlog_recovery_process_trans(
2227 struct xlog *log,
2228 struct xlog_recover *trans,
2229 char *dp,
2230 unsigned int len,
2231 unsigned int flags,
2232 int pass,
2233 struct list_head *buffer_list)
2234{
2235 int error = 0;
2236 bool freeit = false;
2237
2238 /* mask off ophdr transaction container flags */
2239 flags &= ~XLOG_END_TRANS;
2240 if (flags & XLOG_WAS_CONT_TRANS)
2241 flags &= ~XLOG_CONTINUE_TRANS;
2242
2243 /*
2244 * Callees must not free the trans structure. We'll decide if we need to
2245 * free it or not based on the operation being done and it's result.
2246 */
2247 switch (flags) {
2248 /* expected flag values */
2249 case 0:
2250 case XLOG_CONTINUE_TRANS:
2251 error = xlog_recover_add_to_trans(log, trans, dp, len);
2252 break;
2253 case XLOG_WAS_CONT_TRANS:
2254 error = xlog_recover_add_to_cont_trans(log, trans, dp, len);
2255 break;
2256 case XLOG_COMMIT_TRANS:
2257 error = xlog_recover_commit_trans(log, trans, pass,
2258 buffer_list);
2259 /* success or fail, we are now done with this transaction. */
2260 freeit = true;
2261 break;
2262
2263 /* unexpected flag values */
2264 case XLOG_UNMOUNT_TRANS:
2265 /* just skip trans */
2266 xfs_warn(log->l_mp, "%s: Unmount LR", __func__);
2267 freeit = true;
2268 break;
2269 case XLOG_START_TRANS:
2270 default:
2271 xfs_warn(log->l_mp, "%s: bad flag 0x%x", __func__, flags);
2272 ASSERT(0);
2273 error = -EFSCORRUPTED;
2274 break;
2275 }
2276 if (error || freeit)
2277 xlog_recover_free_trans(trans);
2278 return error;
2279}
2280
2281/*
2282 * Lookup the transaction recovery structure associated with the ID in the
2283 * current ophdr. If the transaction doesn't exist and the start flag is set in
2284 * the ophdr, then allocate a new transaction for future ID matches to find.
2285 * Either way, return what we found during the lookup - an existing transaction
2286 * or nothing.
2287 */
2288STATIC struct xlog_recover *
2289xlog_recover_ophdr_to_trans(
2290 struct hlist_head rhash[],
2291 struct xlog_rec_header *rhead,
2292 struct xlog_op_header *ohead)
2293{
2294 struct xlog_recover *trans;
2295 xlog_tid_t tid;
2296 struct hlist_head *rhp;
2297
2298 tid = be32_to_cpu(ohead->oh_tid);
2299 rhp = &rhash[XLOG_RHASH(tid)];
2300 hlist_for_each_entry(trans, rhp, r_list) {
2301 if (trans->r_log_tid == tid)
2302 return trans;
2303 }
2304
2305 /*
2306 * skip over non-start transaction headers - we could be
2307 * processing slack space before the next transaction starts
2308 */
2309 if (!(ohead->oh_flags & XLOG_START_TRANS))
2310 return NULL;
2311
2312 ASSERT(be32_to_cpu(ohead->oh_len) == 0);
2313
2314 /*
2315 * This is a new transaction so allocate a new recovery container to
2316 * hold the recovery ops that will follow.
2317 */
2318 trans = kmem_zalloc(sizeof(struct xlog_recover), 0);
2319 trans->r_log_tid = tid;
2320 trans->r_lsn = be64_to_cpu(rhead->h_lsn);
2321 INIT_LIST_HEAD(list: &trans->r_itemq);
2322 INIT_HLIST_NODE(h: &trans->r_list);
2323 hlist_add_head(n: &trans->r_list, h: rhp);
2324
2325 /*
2326 * Nothing more to do for this ophdr. Items to be added to this new
2327 * transaction will be in subsequent ophdr containers.
2328 */
2329 return NULL;
2330}
2331
2332STATIC int
2333xlog_recover_process_ophdr(
2334 struct xlog *log,
2335 struct hlist_head rhash[],
2336 struct xlog_rec_header *rhead,
2337 struct xlog_op_header *ohead,
2338 char *dp,
2339 char *end,
2340 int pass,
2341 struct list_head *buffer_list)
2342{
2343 struct xlog_recover *trans;
2344 unsigned int len;
2345 int error;
2346
2347 /* Do we understand who wrote this op? */
2348 if (ohead->oh_clientid != XFS_TRANSACTION &&
2349 ohead->oh_clientid != XFS_LOG) {
2350 xfs_warn(log->l_mp, "%s: bad clientid 0x%x",
2351 __func__, ohead->oh_clientid);
2352 ASSERT(0);
2353 return -EFSCORRUPTED;
2354 }
2355
2356 /*
2357 * Check the ophdr contains all the data it is supposed to contain.
2358 */
2359 len = be32_to_cpu(ohead->oh_len);
2360 if (dp + len > end) {
2361 xfs_warn(log->l_mp, "%s: bad length 0x%x", __func__, len);
2362 WARN_ON(1);
2363 return -EFSCORRUPTED;
2364 }
2365
2366 trans = xlog_recover_ophdr_to_trans(rhash, rhead, ohead);
2367 if (!trans) {
2368 /* nothing to do, so skip over this ophdr */
2369 return 0;
2370 }
2371
2372 /*
2373 * The recovered buffer queue is drained only once we know that all
2374 * recovery items for the current LSN have been processed. This is
2375 * required because:
2376 *
2377 * - Buffer write submission updates the metadata LSN of the buffer.
2378 * - Log recovery skips items with a metadata LSN >= the current LSN of
2379 * the recovery item.
2380 * - Separate recovery items against the same metadata buffer can share
2381 * a current LSN. I.e., consider that the LSN of a recovery item is
2382 * defined as the starting LSN of the first record in which its
2383 * transaction appears, that a record can hold multiple transactions,
2384 * and/or that a transaction can span multiple records.
2385 *
2386 * In other words, we are allowed to submit a buffer from log recovery
2387 * once per current LSN. Otherwise, we may incorrectly skip recovery
2388 * items and cause corruption.
2389 *
2390 * We don't know up front whether buffers are updated multiple times per
2391 * LSN. Therefore, track the current LSN of each commit log record as it
2392 * is processed and drain the queue when it changes. Use commit records
2393 * because they are ordered correctly by the logging code.
2394 */
2395 if (log->l_recovery_lsn != trans->r_lsn &&
2396 ohead->oh_flags & XLOG_COMMIT_TRANS) {
2397 error = xfs_buf_delwri_submit(buffer_list);
2398 if (error)
2399 return error;
2400 log->l_recovery_lsn = trans->r_lsn;
2401 }
2402
2403 return xlog_recovery_process_trans(log, trans, dp, len,
2404 flags: ohead->oh_flags, pass, buffer_list);
2405}
2406
2407/*
2408 * There are two valid states of the r_state field. 0 indicates that the
2409 * transaction structure is in a normal state. We have either seen the
2410 * start of the transaction or the last operation we added was not a partial
2411 * operation. If the last operation we added to the transaction was a
2412 * partial operation, we need to mark r_state with XLOG_WAS_CONT_TRANS.
2413 *
2414 * NOTE: skip LRs with 0 data length.
2415 */
2416STATIC int
2417xlog_recover_process_data(
2418 struct xlog *log,
2419 struct hlist_head rhash[],
2420 struct xlog_rec_header *rhead,
2421 char *dp,
2422 int pass,
2423 struct list_head *buffer_list)
2424{
2425 struct xlog_op_header *ohead;
2426 char *end;
2427 int num_logops;
2428 int error;
2429
2430 end = dp + be32_to_cpu(rhead->h_len);
2431 num_logops = be32_to_cpu(rhead->h_num_logops);
2432
2433 /* check the log format matches our own - else we can't recover */
2434 if (xlog_header_check_recover(log->l_mp, rhead))
2435 return -EIO;
2436
2437 trace_xfs_log_recover_record(log, rhead, pass);
2438 while ((dp < end) && num_logops) {
2439
2440 ohead = (struct xlog_op_header *)dp;
2441 dp += sizeof(*ohead);
2442 ASSERT(dp <= end);
2443
2444 /* errors will abort recovery */
2445 error = xlog_recover_process_ophdr(log, rhash, rhead, ohead,
2446 dp, end, pass, buffer_list);
2447 if (error)
2448 return error;
2449
2450 dp += be32_to_cpu(ohead->oh_len);
2451 num_logops--;
2452 }
2453 return 0;
2454}
2455
2456/* Take all the collected deferred ops and finish them in order. */
2457static int
2458xlog_finish_defer_ops(
2459 struct xfs_mount *mp,
2460 struct list_head *capture_list)
2461{
2462 struct xfs_defer_capture *dfc, *next;
2463 struct xfs_trans *tp;
2464 int error = 0;
2465
2466 list_for_each_entry_safe(dfc, next, capture_list, dfc_list) {
2467 struct xfs_trans_res resv;
2468 struct xfs_defer_resources dres;
2469
2470 /*
2471 * Create a new transaction reservation from the captured
2472 * information. Set logcount to 1 to force the new transaction
2473 * to regrant every roll so that we can make forward progress
2474 * in recovery no matter how full the log might be.
2475 */
2476 resv.tr_logres = dfc->dfc_logres;
2477 resv.tr_logcount = 1;
2478 resv.tr_logflags = XFS_TRANS_PERM_LOG_RES;
2479
2480 error = xfs_trans_alloc(mp, &resv, dfc->dfc_blkres,
2481 dfc->dfc_rtxres, XFS_TRANS_RESERVE, &tp);
2482 if (error) {
2483 xlog_force_shutdown(log: mp->m_log, SHUTDOWN_LOG_IO_ERROR);
2484 return error;
2485 }
2486
2487 /*
2488 * Transfer to this new transaction all the dfops we captured
2489 * from recovering a single intent item.
2490 */
2491 list_del_init(entry: &dfc->dfc_list);
2492 xfs_defer_ops_continue(dfc, tp, &dres);
2493 error = xfs_trans_commit(tp);
2494 xfs_defer_resources_rele(&dres);
2495 if (error)
2496 return error;
2497 }
2498
2499 ASSERT(list_empty(capture_list));
2500 return 0;
2501}
2502
2503/* Release all the captured defer ops and capture structures in this list. */
2504static void
2505xlog_abort_defer_ops(
2506 struct xfs_mount *mp,
2507 struct list_head *capture_list)
2508{
2509 struct xfs_defer_capture *dfc;
2510 struct xfs_defer_capture *next;
2511
2512 list_for_each_entry_safe(dfc, next, capture_list, dfc_list) {
2513 list_del_init(entry: &dfc->dfc_list);
2514 xfs_defer_ops_capture_free(mp, dfc);
2515 }
2516}
2517
2518/*
2519 * When this is called, all of the log intent items which did not have
2520 * corresponding log done items should be in the AIL. What we do now is update
2521 * the data structures associated with each one.
2522 *
2523 * Since we process the log intent items in normal transactions, they will be
2524 * removed at some point after the commit. This prevents us from just walking
2525 * down the list processing each one. We'll use a flag in the intent item to
2526 * skip those that we've already processed and use the AIL iteration mechanism's
2527 * generation count to try to speed this up at least a bit.
2528 *
2529 * When we start, we know that the intents are the only things in the AIL. As we
2530 * process them, however, other items are added to the AIL. Hence we know we
2531 * have started recovery on all the pending intents when we find an non-intent
2532 * item in the AIL.
2533 */
2534STATIC int
2535xlog_recover_process_intents(
2536 struct xlog *log)
2537{
2538 LIST_HEAD(capture_list);
2539 struct xfs_ail_cursor cur;
2540 struct xfs_log_item *lip;
2541 struct xfs_ail *ailp;
2542 int error = 0;
2543#if defined(DEBUG) || defined(XFS_WARN)
2544 xfs_lsn_t last_lsn;
2545#endif
2546
2547 ailp = log->l_ailp;
2548 spin_lock(lock: &ailp->ail_lock);
2549#if defined(DEBUG) || defined(XFS_WARN)
2550 last_lsn = xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block);
2551#endif
2552 for (lip = xfs_trans_ail_cursor_first(ailp, &cur, 0);
2553 lip != NULL;
2554 lip = xfs_trans_ail_cursor_next(ailp, cur: &cur)) {
2555 const struct xfs_item_ops *ops;
2556
2557 if (!xlog_item_is_intent(lip))
2558 break;
2559
2560 /*
2561 * We should never see a redo item with a LSN higher than
2562 * the last transaction we found in the log at the start
2563 * of recovery.
2564 */
2565 ASSERT(XFS_LSN_CMP(last_lsn, lip->li_lsn) >= 0);
2566
2567 /*
2568 * NOTE: If your intent processing routine can create more
2569 * deferred ops, you /must/ attach them to the capture list in
2570 * the recover routine or else those subsequent intents will be
2571 * replayed in the wrong order!
2572 *
2573 * The recovery function can free the log item, so we must not
2574 * access lip after it returns.
2575 */
2576 spin_unlock(lock: &ailp->ail_lock);
2577 ops = lip->li_ops;
2578 error = ops->iop_recover(lip, &capture_list);
2579 spin_lock(lock: &ailp->ail_lock);
2580 if (error) {
2581 trace_xlog_intent_recovery_failed(mp: log->l_mp, error,
2582 function: ops->iop_recover);
2583 break;
2584 }
2585 }
2586
2587 xfs_trans_ail_cursor_done(cur: &cur);
2588 spin_unlock(lock: &ailp->ail_lock);
2589 if (error)
2590 goto err;
2591
2592 error = xlog_finish_defer_ops(mp: log->l_mp, capture_list: &capture_list);
2593 if (error)
2594 goto err;
2595
2596 return 0;
2597err:
2598 xlog_abort_defer_ops(mp: log->l_mp, capture_list: &capture_list);
2599 return error;
2600}
2601
2602/*
2603 * A cancel occurs when the mount has failed and we're bailing out. Release all
2604 * pending log intent items that we haven't started recovery on so they don't
2605 * pin the AIL.
2606 */
2607STATIC void
2608xlog_recover_cancel_intents(
2609 struct xlog *log)
2610{
2611 struct xfs_log_item *lip;
2612 struct xfs_ail_cursor cur;
2613 struct xfs_ail *ailp;
2614
2615 ailp = log->l_ailp;
2616 spin_lock(lock: &ailp->ail_lock);
2617 lip = xfs_trans_ail_cursor_first(ailp, &cur, 0);
2618 while (lip != NULL) {
2619 if (!xlog_item_is_intent(lip))
2620 break;
2621
2622 spin_unlock(lock: &ailp->ail_lock);
2623 lip->li_ops->iop_release(lip);
2624 spin_lock(lock: &ailp->ail_lock);
2625 lip = xfs_trans_ail_cursor_next(ailp, cur: &cur);
2626 }
2627
2628 xfs_trans_ail_cursor_done(cur: &cur);
2629 spin_unlock(lock: &ailp->ail_lock);
2630}
2631
2632/*
2633 * This routine performs a transaction to null out a bad inode pointer
2634 * in an agi unlinked inode hash bucket.
2635 */
2636STATIC void
2637xlog_recover_clear_agi_bucket(
2638 struct xfs_perag *pag,
2639 int bucket)
2640{
2641 struct xfs_mount *mp = pag->pag_mount;
2642 struct xfs_trans *tp;
2643 struct xfs_agi *agi;
2644 struct xfs_buf *agibp;
2645 int offset;
2646 int error;
2647
2648 error = xfs_trans_alloc(mp, resp: &M_RES(mp)->tr_clearagi, blocks: 0, rtextents: 0, flags: 0, tpp: &tp);
2649 if (error)
2650 goto out_error;
2651
2652 error = xfs_read_agi(pag, tp, &agibp);
2653 if (error)
2654 goto out_abort;
2655
2656 agi = agibp->b_addr;
2657 agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
2658 offset = offsetof(xfs_agi_t, agi_unlinked) +
2659 (sizeof(xfs_agino_t) * bucket);
2660 xfs_trans_log_buf(tp, agibp, offset,
2661 (offset + sizeof(xfs_agino_t) - 1));
2662
2663 error = xfs_trans_commit(tp);
2664 if (error)
2665 goto out_error;
2666 return;
2667
2668out_abort:
2669 xfs_trans_cancel(tp);
2670out_error:
2671 xfs_warn(mp, "%s: failed to clear agi %d. Continuing.", __func__,
2672 pag->pag_agno);
2673 return;
2674}
2675
2676static int
2677xlog_recover_iunlink_bucket(
2678 struct xfs_perag *pag,
2679 struct xfs_agi *agi,
2680 int bucket)
2681{
2682 struct xfs_mount *mp = pag->pag_mount;
2683 struct xfs_inode *prev_ip = NULL;
2684 struct xfs_inode *ip;
2685 xfs_agino_t prev_agino, agino;
2686 int error = 0;
2687
2688 agino = be32_to_cpu(agi->agi_unlinked[bucket]);
2689 while (agino != NULLAGINO) {
2690 error = xfs_iget(mp, NULL,
2691 XFS_AGINO_TO_INO(mp, pag->pag_agno, agino),
2692 0, 0, &ip);
2693 if (error)
2694 break;
2695
2696 ASSERT(VFS_I(ip)->i_nlink == 0);
2697 ASSERT(VFS_I(ip)->i_mode != 0);
2698 xfs_iflags_clear(ip, XFS_IRECOVERY);
2699 agino = ip->i_next_unlinked;
2700
2701 if (prev_ip) {
2702 ip->i_prev_unlinked = prev_agino;
2703 xfs_irele(ip: prev_ip);
2704
2705 /*
2706 * Ensure the inode is removed from the unlinked list
2707 * before we continue so that it won't race with
2708 * building the in-memory list here. This could be
2709 * serialised with the agibp lock, but that just
2710 * serialises via lockstepping and it's much simpler
2711 * just to flush the inodegc queue and wait for it to
2712 * complete.
2713 */
2714 error = xfs_inodegc_flush(mp);
2715 if (error)
2716 break;
2717 }
2718
2719 prev_agino = agino;
2720 prev_ip = ip;
2721 }
2722
2723 if (prev_ip) {
2724 int error2;
2725
2726 ip->i_prev_unlinked = prev_agino;
2727 xfs_irele(ip: prev_ip);
2728
2729 error2 = xfs_inodegc_flush(mp);
2730 if (error2 && !error)
2731 return error2;
2732 }
2733 return error;
2734}
2735
2736/*
2737 * Recover AGI unlinked lists
2738 *
2739 * This is called during recovery to process any inodes which we unlinked but
2740 * not freed when the system crashed. These inodes will be on the lists in the
2741 * AGI blocks. What we do here is scan all the AGIs and fully truncate and free
2742 * any inodes found on the lists. Each inode is removed from the lists when it
2743 * has been fully truncated and is freed. The freeing of the inode and its
2744 * removal from the list must be atomic.
2745 *
2746 * If everything we touch in the agi processing loop is already in memory, this
2747 * loop can hold the cpu for a long time. It runs without lock contention,
2748 * memory allocation contention, the need wait for IO, etc, and so will run
2749 * until we either run out of inodes to process, run low on memory or we run out
2750 * of log space.
2751 *
2752 * This behaviour is bad for latency on single CPU and non-preemptible kernels,
2753 * and can prevent other filesystem work (such as CIL pushes) from running. This
2754 * can lead to deadlocks if the recovery process runs out of log reservation
2755 * space. Hence we need to yield the CPU when there is other kernel work
2756 * scheduled on this CPU to ensure other scheduled work can run without undue
2757 * latency.
2758 */
2759static void
2760xlog_recover_iunlink_ag(
2761 struct xfs_perag *pag)
2762{
2763 struct xfs_agi *agi;
2764 struct xfs_buf *agibp;
2765 int bucket;
2766 int error;
2767
2768 error = xfs_read_agi(pag, NULL, &agibp);
2769 if (error) {
2770 /*
2771 * AGI is b0rked. Don't process it.
2772 *
2773 * We should probably mark the filesystem as corrupt after we've
2774 * recovered all the ag's we can....
2775 */
2776 return;
2777 }
2778
2779 /*
2780 * Unlock the buffer so that it can be acquired in the normal course of
2781 * the transaction to truncate and free each inode. Because we are not
2782 * racing with anyone else here for the AGI buffer, we don't even need
2783 * to hold it locked to read the initial unlinked bucket entries out of
2784 * the buffer. We keep buffer reference though, so that it stays pinned
2785 * in memory while we need the buffer.
2786 */
2787 agi = agibp->b_addr;
2788 xfs_buf_unlock(agibp);
2789
2790 for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++) {
2791 error = xlog_recover_iunlink_bucket(pag, agi, bucket);
2792 if (error) {
2793 /*
2794 * Bucket is unrecoverable, so only a repair scan can
2795 * free the remaining unlinked inodes. Just empty the
2796 * bucket and remaining inodes on it unreferenced and
2797 * unfreeable.
2798 */
2799 xlog_recover_clear_agi_bucket(pag, bucket);
2800 }
2801 }
2802
2803 xfs_buf_rele(agibp);
2804}
2805
2806static void
2807xlog_recover_process_iunlinks(
2808 struct xlog *log)
2809{
2810 struct xfs_perag *pag;
2811 xfs_agnumber_t agno;
2812
2813 for_each_perag(log->l_mp, agno, pag)
2814 xlog_recover_iunlink_ag(pag);
2815}
2816
2817STATIC void
2818xlog_unpack_data(
2819 struct xlog_rec_header *rhead,
2820 char *dp,
2821 struct xlog *log)
2822{
2823 int i, j, k;
2824
2825 for (i = 0; i < BTOBB(be32_to_cpu(rhead->h_len)) &&
2826 i < (XLOG_HEADER_CYCLE_SIZE / BBSIZE); i++) {
2827 *(__be32 *)dp = *(__be32 *)&rhead->h_cycle_data[i];
2828 dp += BBSIZE;
2829 }
2830
2831 if (xfs_has_logv2(mp: log->l_mp)) {
2832 xlog_in_core_2_t *xhdr = (xlog_in_core_2_t *)rhead;
2833 for ( ; i < BTOBB(be32_to_cpu(rhead->h_len)); i++) {
2834 j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
2835 k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
2836 *(__be32 *)dp = xhdr[j].hic_xheader.xh_cycle_data[k];
2837 dp += BBSIZE;
2838 }
2839 }
2840}
2841
2842/*
2843 * CRC check, unpack and process a log record.
2844 */
2845STATIC int
2846xlog_recover_process(
2847 struct xlog *log,
2848 struct hlist_head rhash[],
2849 struct xlog_rec_header *rhead,
2850 char *dp,
2851 int pass,
2852 struct list_head *buffer_list)
2853{
2854 __le32 old_crc = rhead->h_crc;
2855 __le32 crc;
2856
2857 crc = xlog_cksum(log, rhead, dp, be32_to_cpu(rhead->h_len));
2858
2859 /*
2860 * Nothing else to do if this is a CRC verification pass. Just return
2861 * if this a record with a non-zero crc. Unfortunately, mkfs always
2862 * sets old_crc to 0 so we must consider this valid even on v5 supers.
2863 * Otherwise, return EFSBADCRC on failure so the callers up the stack
2864 * know precisely what failed.
2865 */
2866 if (pass == XLOG_RECOVER_CRCPASS) {
2867 if (old_crc && crc != old_crc)
2868 return -EFSBADCRC;
2869 return 0;
2870 }
2871
2872 /*
2873 * We're in the normal recovery path. Issue a warning if and only if the
2874 * CRC in the header is non-zero. This is an advisory warning and the
2875 * zero CRC check prevents warnings from being emitted when upgrading
2876 * the kernel from one that does not add CRCs by default.
2877 */
2878 if (crc != old_crc) {
2879 if (old_crc || xfs_has_crc(mp: log->l_mp)) {
2880 xfs_alert(log->l_mp,
2881 "log record CRC mismatch: found 0x%x, expected 0x%x.",
2882 le32_to_cpu(old_crc),
2883 le32_to_cpu(crc));
2884 xfs_hex_dump(p: dp, length: 32);
2885 }
2886
2887 /*
2888 * If the filesystem is CRC enabled, this mismatch becomes a
2889 * fatal log corruption failure.
2890 */
2891 if (xfs_has_crc(mp: log->l_mp)) {
2892 XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, log->l_mp);
2893 return -EFSCORRUPTED;
2894 }
2895 }
2896
2897 xlog_unpack_data(rhead, dp, log);
2898
2899 return xlog_recover_process_data(log, rhash, rhead, dp, pass,
2900 buffer_list);
2901}
2902
2903STATIC int
2904xlog_valid_rec_header(
2905 struct xlog *log,
2906 struct xlog_rec_header *rhead,
2907 xfs_daddr_t blkno,
2908 int bufsize)
2909{
2910 int hlen;
2911
2912 if (XFS_IS_CORRUPT(log->l_mp,
2913 rhead->h_magicno != cpu_to_be32(XLOG_HEADER_MAGIC_NUM)))
2914 return -EFSCORRUPTED;
2915 if (XFS_IS_CORRUPT(log->l_mp,
2916 (!rhead->h_version ||
2917 (be32_to_cpu(rhead->h_version) &
2918 (~XLOG_VERSION_OKBITS))))) {
2919 xfs_warn(log->l_mp, "%s: unrecognised log version (%d).",
2920 __func__, be32_to_cpu(rhead->h_version));
2921 return -EFSCORRUPTED;
2922 }
2923
2924 /*
2925 * LR body must have data (or it wouldn't have been written)
2926 * and h_len must not be greater than LR buffer size.
2927 */
2928 hlen = be32_to_cpu(rhead->h_len);
2929 if (XFS_IS_CORRUPT(log->l_mp, hlen <= 0 || hlen > bufsize))
2930 return -EFSCORRUPTED;
2931
2932 if (XFS_IS_CORRUPT(log->l_mp,
2933 blkno > log->l_logBBsize || blkno > INT_MAX))
2934 return -EFSCORRUPTED;
2935 return 0;
2936}
2937
2938/*
2939 * Read the log from tail to head and process the log records found.
2940 * Handle the two cases where the tail and head are in the same cycle
2941 * and where the active portion of the log wraps around the end of
2942 * the physical log separately. The pass parameter is passed through
2943 * to the routines called to process the data and is not looked at
2944 * here.
2945 */
2946STATIC int
2947xlog_do_recovery_pass(
2948 struct xlog *log,
2949 xfs_daddr_t head_blk,
2950 xfs_daddr_t tail_blk,
2951 int pass,
2952 xfs_daddr_t *first_bad) /* out: first bad log rec */
2953{
2954 xlog_rec_header_t *rhead;
2955 xfs_daddr_t blk_no, rblk_no;
2956 xfs_daddr_t rhead_blk;
2957 char *offset;
2958 char *hbp, *dbp;
2959 int error = 0, h_size, h_len;
2960 int error2 = 0;
2961 int bblks, split_bblks;
2962 int hblks, split_hblks, wrapped_hblks;
2963 int i;
2964 struct hlist_head rhash[XLOG_RHASH_SIZE];
2965 LIST_HEAD (buffer_list);
2966
2967 ASSERT(head_blk != tail_blk);
2968 blk_no = rhead_blk = tail_blk;
2969
2970 for (i = 0; i < XLOG_RHASH_SIZE; i++)
2971 INIT_HLIST_HEAD(&rhash[i]);
2972
2973 /*
2974 * Read the header of the tail block and get the iclog buffer size from
2975 * h_size. Use this to tell how many sectors make up the log header.
2976 */
2977 if (xfs_has_logv2(mp: log->l_mp)) {
2978 /*
2979 * When using variable length iclogs, read first sector of
2980 * iclog header and extract the header size from it. Get a
2981 * new hbp that is the correct size.
2982 */
2983 hbp = xlog_alloc_buffer(log, nbblks: 1);
2984 if (!hbp)
2985 return -ENOMEM;
2986
2987 error = xlog_bread(log, blk_no: tail_blk, nbblks: 1, data: hbp, offset: &offset);
2988 if (error)
2989 goto bread_err1;
2990
2991 rhead = (xlog_rec_header_t *)offset;
2992
2993 /*
2994 * xfsprogs has a bug where record length is based on lsunit but
2995 * h_size (iclog size) is hardcoded to 32k. Now that we
2996 * unconditionally CRC verify the unmount record, this means the
2997 * log buffer can be too small for the record and cause an
2998 * overrun.
2999 *
3000 * Detect this condition here. Use lsunit for the buffer size as
3001 * long as this looks like the mkfs case. Otherwise, return an
3002 * error to avoid a buffer overrun.
3003 */
3004 h_size = be32_to_cpu(rhead->h_size);
3005 h_len = be32_to_cpu(rhead->h_len);
3006 if (h_len > h_size && h_len <= log->l_mp->m_logbsize &&
3007 rhead->h_num_logops == cpu_to_be32(1)) {
3008 xfs_warn(log->l_mp,
3009 "invalid iclog size (%d bytes), using lsunit (%d bytes)",
3010 h_size, log->l_mp->m_logbsize);
3011 h_size = log->l_mp->m_logbsize;
3012 }
3013
3014 error = xlog_valid_rec_header(log, rhead, tail_blk, h_size);
3015 if (error)
3016 goto bread_err1;
3017
3018 hblks = xlog_logrec_hblks(log, rhead);
3019 if (hblks != 1) {
3020 kmem_free(ptr: hbp);
3021 hbp = xlog_alloc_buffer(log, nbblks: hblks);
3022 }
3023 } else {
3024 ASSERT(log->l_sectBBsize == 1);
3025 hblks = 1;
3026 hbp = xlog_alloc_buffer(log, nbblks: 1);
3027 h_size = XLOG_BIG_RECORD_BSIZE;
3028 }
3029
3030 if (!hbp)
3031 return -ENOMEM;
3032 dbp = xlog_alloc_buffer(log, nbblks: BTOBB(h_size));
3033 if (!dbp) {
3034 kmem_free(ptr: hbp);
3035 return -ENOMEM;
3036 }
3037
3038 memset(rhash, 0, sizeof(rhash));
3039 if (tail_blk > head_blk) {
3040 /*
3041 * Perform recovery around the end of the physical log.
3042 * When the head is not on the same cycle number as the tail,
3043 * we can't do a sequential recovery.
3044 */
3045 while (blk_no < log->l_logBBsize) {
3046 /*
3047 * Check for header wrapping around physical end-of-log
3048 */
3049 offset = hbp;
3050 split_hblks = 0;
3051 wrapped_hblks = 0;
3052 if (blk_no + hblks <= log->l_logBBsize) {
3053 /* Read header in one read */
3054 error = xlog_bread(log, blk_no, nbblks: hblks, data: hbp,
3055 offset: &offset);
3056 if (error)
3057 goto bread_err2;
3058 } else {
3059 /* This LR is split across physical log end */
3060 if (blk_no != log->l_logBBsize) {
3061 /* some data before physical log end */
3062 ASSERT(blk_no <= INT_MAX);
3063 split_hblks = log->l_logBBsize - (int)blk_no;
3064 ASSERT(split_hblks > 0);
3065 error = xlog_bread(log, blk_no,
3066 nbblks: split_hblks, data: hbp,
3067 offset: &offset);
3068 if (error)
3069 goto bread_err2;
3070 }
3071
3072 /*
3073 * Note: this black magic still works with
3074 * large sector sizes (non-512) only because:
3075 * - we increased the buffer size originally
3076 * by 1 sector giving us enough extra space
3077 * for the second read;
3078 * - the log start is guaranteed to be sector
3079 * aligned;
3080 * - we read the log end (LR header start)
3081 * _first_, then the log start (LR header end)
3082 * - order is important.
3083 */
3084 wrapped_hblks = hblks - split_hblks;
3085 error = xlog_bread_noalign(log, blk_no: 0,
3086 nbblks: wrapped_hblks,
3087 data: offset + BBTOB(split_hblks));
3088 if (error)
3089 goto bread_err2;
3090 }
3091 rhead = (xlog_rec_header_t *)offset;
3092 error = xlog_valid_rec_header(log, rhead,
3093 split_hblks ? blk_no : 0, h_size);
3094 if (error)
3095 goto bread_err2;
3096
3097 bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
3098 blk_no += hblks;
3099
3100 /*
3101 * Read the log record data in multiple reads if it
3102 * wraps around the end of the log. Note that if the
3103 * header already wrapped, blk_no could point past the
3104 * end of the log. The record data is contiguous in
3105 * that case.
3106 */
3107 if (blk_no + bblks <= log->l_logBBsize ||
3108 blk_no >= log->l_logBBsize) {
3109 rblk_no = xlog_wrap_logbno(log, bno: blk_no);
3110 error = xlog_bread(log, blk_no: rblk_no, nbblks: bblks, data: dbp,
3111 offset: &offset);
3112 if (error)
3113 goto bread_err2;
3114 } else {
3115 /* This log record is split across the
3116 * physical end of log */
3117 offset = dbp;
3118 split_bblks = 0;
3119 if (blk_no != log->l_logBBsize) {
3120 /* some data is before the physical
3121 * end of log */
3122 ASSERT(!wrapped_hblks);
3123 ASSERT(blk_no <= INT_MAX);
3124 split_bblks =
3125 log->l_logBBsize - (int)blk_no;
3126 ASSERT(split_bblks > 0);
3127 error = xlog_bread(log, blk_no,
3128 nbblks: split_bblks, data: dbp,
3129 offset: &offset);
3130 if (error)
3131 goto bread_err2;
3132 }
3133
3134 /*
3135 * Note: this black magic still works with
3136 * large sector sizes (non-512) only because:
3137 * - we increased the buffer size originally
3138 * by 1 sector giving us enough extra space
3139 * for the second read;
3140 * - the log start is guaranteed to be sector
3141 * aligned;
3142 * - we read the log end (LR header start)
3143 * _first_, then the log start (LR header end)
3144 * - order is important.
3145 */
3146 error = xlog_bread_noalign(log, blk_no: 0,
3147 nbblks: bblks - split_bblks,
3148 data: offset + BBTOB(split_bblks));
3149 if (error)
3150 goto bread_err2;
3151 }
3152
3153 error = xlog_recover_process(log, rhash, rhead, offset,
3154 pass, &buffer_list);
3155 if (error)
3156 goto bread_err2;
3157
3158 blk_no += bblks;
3159 rhead_blk = blk_no;
3160 }
3161
3162 ASSERT(blk_no >= log->l_logBBsize);
3163 blk_no -= log->l_logBBsize;
3164 rhead_blk = blk_no;
3165 }
3166
3167 /* read first part of physical log */
3168 while (blk_no < head_blk) {
3169 error = xlog_bread(log, blk_no, nbblks: hblks, data: hbp, offset: &offset);
3170 if (error)
3171 goto bread_err2;
3172
3173 rhead = (xlog_rec_header_t *)offset;
3174 error = xlog_valid_rec_header(log, rhead, blk_no, h_size);
3175 if (error)
3176 goto bread_err2;
3177
3178 /* blocks in data section */
3179 bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
3180 error = xlog_bread(log, blk_no: blk_no+hblks, nbblks: bblks, data: dbp,
3181 offset: &offset);
3182 if (error)
3183 goto bread_err2;
3184
3185 error = xlog_recover_process(log, rhash, rhead, offset, pass,
3186 &buffer_list);
3187 if (error)
3188 goto bread_err2;
3189
3190 blk_no += bblks + hblks;
3191 rhead_blk = blk_no;
3192 }
3193
3194 bread_err2:
3195 kmem_free(ptr: dbp);
3196 bread_err1:
3197 kmem_free(ptr: hbp);
3198
3199 /*
3200 * Submit buffers that have been added from the last record processed,
3201 * regardless of error status.
3202 */
3203 if (!list_empty(head: &buffer_list))
3204 error2 = xfs_buf_delwri_submit(&buffer_list);
3205
3206 if (error && first_bad)
3207 *first_bad = rhead_blk;
3208
3209 /*
3210 * Transactions are freed at commit time but transactions without commit
3211 * records on disk are never committed. Free any that may be left in the
3212 * hash table.
3213 */
3214 for (i = 0; i < XLOG_RHASH_SIZE; i++) {
3215 struct hlist_node *tmp;
3216 struct xlog_recover *trans;
3217
3218 hlist_for_each_entry_safe(trans, tmp, &rhash[i], r_list)
3219 xlog_recover_free_trans(trans);
3220 }
3221
3222 return error ? error : error2;
3223}
3224
3225/*
3226 * Do the recovery of the log. We actually do this in two phases.
3227 * The two passes are necessary in order to implement the function
3228 * of cancelling a record written into the log. The first pass
3229 * determines those things which have been cancelled, and the
3230 * second pass replays log items normally except for those which
3231 * have been cancelled. The handling of the replay and cancellations
3232 * takes place in the log item type specific routines.
3233 *
3234 * The table of items which have cancel records in the log is allocated
3235 * and freed at this level, since only here do we know when all of
3236 * the log recovery has been completed.
3237 */
3238STATIC int
3239xlog_do_log_recovery(
3240 struct xlog *log,
3241 xfs_daddr_t head_blk,
3242 xfs_daddr_t tail_blk)
3243{
3244 int error;
3245
3246 ASSERT(head_blk != tail_blk);
3247
3248 /*
3249 * First do a pass to find all of the cancelled buf log items.
3250 * Store them in the buf_cancel_table for use in the second pass.
3251 */
3252 error = xlog_alloc_buf_cancel_table(log);
3253 if (error)
3254 return error;
3255
3256 error = xlog_do_recovery_pass(log, head_blk, tail_blk,
3257 XLOG_RECOVER_PASS1, NULL);
3258 if (error != 0)
3259 goto out_cancel;
3260
3261 /*
3262 * Then do a second pass to actually recover the items in the log.
3263 * When it is complete free the table of buf cancel items.
3264 */
3265 error = xlog_do_recovery_pass(log, head_blk, tail_blk,
3266 XLOG_RECOVER_PASS2, NULL);
3267 if (!error)
3268 xlog_check_buf_cancel_table(log);
3269out_cancel:
3270 xlog_free_buf_cancel_table(log);
3271 return error;
3272}
3273
3274/*
3275 * Do the actual recovery
3276 */
3277STATIC int
3278xlog_do_recover(
3279 struct xlog *log,
3280 xfs_daddr_t head_blk,
3281 xfs_daddr_t tail_blk)
3282{
3283 struct xfs_mount *mp = log->l_mp;
3284 struct xfs_buf *bp = mp->m_sb_bp;
3285 struct xfs_sb *sbp = &mp->m_sb;
3286 int error;
3287
3288 trace_xfs_log_recover(log, headblk: head_blk, tailblk: tail_blk);
3289
3290 /*
3291 * First replay the images in the log.
3292 */
3293 error = xlog_do_log_recovery(log, head_blk, tail_blk);
3294 if (error)
3295 return error;
3296
3297 if (xlog_is_shutdown(log))
3298 return -EIO;
3299
3300 /*
3301 * We now update the tail_lsn since much of the recovery has completed
3302 * and there may be space available to use. If there were no extent
3303 * or iunlinks, we can free up the entire log and set the tail_lsn to
3304 * be the last_sync_lsn. This was set in xlog_find_tail to be the
3305 * lsn of the last known good LR on disk. If there are extent frees
3306 * or iunlinks they will have some entries in the AIL; so we look at
3307 * the AIL to determine how to set the tail_lsn.
3308 */
3309 xlog_assign_tail_lsn(mp);
3310
3311 /*
3312 * Now that we've finished replaying all buffer and inode updates,
3313 * re-read the superblock and reverify it.
3314 */
3315 xfs_buf_lock(bp);
3316 xfs_buf_hold(bp);
3317 error = _xfs_buf_read(bp, XBF_READ);
3318 if (error) {
3319 if (!xlog_is_shutdown(log)) {
3320 xfs_buf_ioerror_alert(bp, __this_address);
3321 ASSERT(0);
3322 }
3323 xfs_buf_relse(bp);
3324 return error;
3325 }
3326
3327 /* Convert superblock from on-disk format */
3328 xfs_sb_from_disk(sbp, bp->b_addr);
3329 xfs_buf_relse(bp);
3330
3331 /* re-initialise in-core superblock and geometry structures */
3332 mp->m_features |= xfs_sb_version_to_features(sbp);
3333 xfs_reinit_percpu_counters(mp);
3334 error = xfs_initialize_perag(mp, sbp->sb_agcount, sbp->sb_dblocks,
3335 &mp->m_maxagi);
3336 if (error) {
3337 xfs_warn(mp, "Failed post-recovery per-ag init: %d", error);
3338 return error;
3339 }
3340 mp->m_alloc_set_aside = xfs_alloc_set_aside(mp);
3341
3342 /* Normal transactions can now occur */
3343 clear_bit(XLOG_ACTIVE_RECOVERY, addr: &log->l_opstate);
3344 return 0;
3345}
3346
3347/*
3348 * Perform recovery and re-initialize some log variables in xlog_find_tail.
3349 *
3350 * Return error or zero.
3351 */
3352int
3353xlog_recover(
3354 struct xlog *log)
3355{
3356 xfs_daddr_t head_blk, tail_blk;
3357 int error;
3358
3359 /* find the tail of the log */
3360 error = xlog_find_tail(log, head_blk: &head_blk, tail_blk: &tail_blk);
3361 if (error)
3362 return error;
3363
3364 /*
3365 * The superblock was read before the log was available and thus the LSN
3366 * could not be verified. Check the superblock LSN against the current
3367 * LSN now that it's known.
3368 */
3369 if (xfs_has_crc(mp: log->l_mp) &&
3370 !xfs_log_check_lsn(log->l_mp, xfs_lsn_t: log->l_mp->m_sb.sb_lsn))
3371 return -EINVAL;
3372
3373 if (tail_blk != head_blk) {
3374 /* There used to be a comment here:
3375 *
3376 * disallow recovery on read-only mounts. note -- mount
3377 * checks for ENOSPC and turns it into an intelligent
3378 * error message.
3379 * ...but this is no longer true. Now, unless you specify
3380 * NORECOVERY (in which case this function would never be
3381 * called), we just go ahead and recover. We do this all
3382 * under the vfs layer, so we can get away with it unless
3383 * the device itself is read-only, in which case we fail.
3384 */
3385 if ((error = xfs_dev_is_read_only(log->l_mp, "recovery"))) {
3386 return error;
3387 }
3388
3389 /*
3390 * Version 5 superblock log feature mask validation. We know the
3391 * log is dirty so check if there are any unknown log features
3392 * in what we need to recover. If there are unknown features
3393 * (e.g. unsupported transactions, then simply reject the
3394 * attempt at recovery before touching anything.
3395 */
3396 if (xfs_sb_is_v5(&log->l_mp->m_sb) &&
3397 xfs_sb_has_incompat_log_feature(&log->l_mp->m_sb,
3398 XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN)) {
3399 xfs_warn(log->l_mp,
3400"Superblock has unknown incompatible log features (0x%x) enabled.",
3401 (log->l_mp->m_sb.sb_features_log_incompat &
3402 XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN));
3403 xfs_warn(log->l_mp,
3404"The log can not be fully and/or safely recovered by this kernel.");
3405 xfs_warn(log->l_mp,
3406"Please recover the log on a kernel that supports the unknown features.");
3407 return -EINVAL;
3408 }
3409
3410 /*
3411 * Delay log recovery if the debug hook is set. This is debug
3412 * instrumentation to coordinate simulation of I/O failures with
3413 * log recovery.
3414 */
3415 if (xfs_globals.log_recovery_delay) {
3416 xfs_notice(log->l_mp,
3417 "Delaying log recovery for %d seconds.",
3418 xfs_globals.log_recovery_delay);
3419 msleep(msecs: xfs_globals.log_recovery_delay * 1000);
3420 }
3421
3422 xfs_notice(log->l_mp, "Starting recovery (logdev: %s)",
3423 log->l_mp->m_logname ? log->l_mp->m_logname
3424 : "internal");
3425
3426 error = xlog_do_recover(log, head_blk, tail_blk);
3427 set_bit(XLOG_RECOVERY_NEEDED, addr: &log->l_opstate);
3428 }
3429 return error;
3430}
3431
3432/*
3433 * In the first part of recovery we replay inodes and buffers and build up the
3434 * list of intents which need to be processed. Here we process the intents and
3435 * clean up the on disk unlinked inode lists. This is separated from the first
3436 * part of recovery so that the root and real-time bitmap inodes can be read in
3437 * from disk in between the two stages. This is necessary so that we can free
3438 * space in the real-time portion of the file system.
3439 */
3440int
3441xlog_recover_finish(
3442 struct xlog *log)
3443{
3444 int error;
3445
3446 error = xlog_recover_process_intents(log);
3447 if (error) {
3448 /*
3449 * Cancel all the unprocessed intent items now so that we don't
3450 * leave them pinned in the AIL. This can cause the AIL to
3451 * livelock on the pinned item if anyone tries to push the AIL
3452 * (inode reclaim does this) before we get around to
3453 * xfs_log_mount_cancel.
3454 */
3455 xlog_recover_cancel_intents(log);
3456 xfs_alert(log->l_mp, "Failed to recover intents");
3457 xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
3458 return error;
3459 }
3460
3461 /*
3462 * Sync the log to get all the intents out of the AIL. This isn't
3463 * absolutely necessary, but it helps in case the unlink transactions
3464 * would have problems pushing the intents out of the way.
3465 */
3466 xfs_log_force(mp: log->l_mp, XFS_LOG_SYNC);
3467
3468 /*
3469 * Now that we've recovered the log and all the intents, we can clear
3470 * the log incompat feature bits in the superblock because there's no
3471 * longer anything to protect. We rely on the AIL push to write out the
3472 * updated superblock after everything else.
3473 */
3474 if (xfs_clear_incompat_log_features(mp: log->l_mp)) {
3475 error = xfs_sync_sb(log->l_mp, false);
3476 if (error < 0) {
3477 xfs_alert(log->l_mp,
3478 "Failed to clear log incompat features on recovery");
3479 return error;
3480 }
3481 }
3482
3483 xlog_recover_process_iunlinks(log);
3484
3485 /*
3486 * Recover any CoW staging blocks that are still referenced by the
3487 * ondisk refcount metadata. During mount there cannot be any live
3488 * staging extents as we have not permitted any user modifications.
3489 * Therefore, it is safe to free them all right now, even on a
3490 * read-only mount.
3491 */
3492 error = xfs_reflink_recover_cow(mp: log->l_mp);
3493 if (error) {
3494 xfs_alert(log->l_mp,
3495 "Failed to recover leftover CoW staging extents, err %d.",
3496 error);
3497 /*
3498 * If we get an error here, make sure the log is shut down
3499 * but return zero so that any log items committed since the
3500 * end of intents processing can be pushed through the CIL
3501 * and AIL.
3502 */
3503 xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
3504 }
3505
3506 return 0;
3507}
3508
3509void
3510xlog_recover_cancel(
3511 struct xlog *log)
3512{
3513 if (xlog_recovery_needed(log))
3514 xlog_recover_cancel_intents(log);
3515}
3516
3517

source code of linux/fs/xfs/xfs_log_recover.c