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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2000-2005 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_mount.h"
13#include "xfs_errortag.h"
14#include "xfs_error.h"
15#include "xfs_trans.h"
16#include "xfs_trans_priv.h"
17#include "xfs_log.h"
18#include "xfs_log_priv.h"
19#include "xfs_trace.h"
20#include "xfs_sysfs.h"
21#include "xfs_sb.h"
22#include "xfs_health.h"
23
24kmem_zone_t *xfs_log_ticket_zone;
25
26/* Local miscellaneous function prototypes */
27STATIC struct xlog *
28xlog_alloc_log(
29 struct xfs_mount *mp,
30 struct xfs_buftarg *log_target,
31 xfs_daddr_t blk_offset,
32 int num_bblks);
33STATIC int
34xlog_space_left(
35 struct xlog *log,
36 atomic64_t *head);
37STATIC void
38xlog_dealloc_log(
39 struct xlog *log);
40
41/* local state machine functions */
42STATIC void xlog_state_done_syncing(
43 struct xlog_in_core *iclog);
44STATIC int
45xlog_state_get_iclog_space(
46 struct xlog *log,
47 int len,
48 struct xlog_in_core **iclog,
49 struct xlog_ticket *ticket,
50 int *continued_write,
51 int *logoffsetp);
52STATIC void
53xlog_state_switch_iclogs(
54 struct xlog *log,
55 struct xlog_in_core *iclog,
56 int eventual_size);
57STATIC void
58xlog_grant_push_ail(
59 struct xlog *log,
60 int need_bytes);
61STATIC void
62xlog_sync(
63 struct xlog *log,
64 struct xlog_in_core *iclog);
65#if defined(DEBUG)
66STATIC void
67xlog_verify_dest_ptr(
68 struct xlog *log,
69 void *ptr);
70STATIC void
71xlog_verify_grant_tail(
72 struct xlog *log);
73STATIC void
74xlog_verify_iclog(
75 struct xlog *log,
76 struct xlog_in_core *iclog,
77 int count);
78STATIC void
79xlog_verify_tail_lsn(
80 struct xlog *log,
81 struct xlog_in_core *iclog);
82#else
83#define xlog_verify_dest_ptr(a,b)
84#define xlog_verify_grant_tail(a)
85#define xlog_verify_iclog(a,b,c)
86#define xlog_verify_tail_lsn(a,b)
87#endif
88
89STATIC int
90xlog_iclogs_empty(
91 struct xlog *log);
92
93static int
94xfs_log_cover(struct xfs_mount *);
95
96static void
97xlog_grant_sub_space(
98 struct xlog *log,
99 atomic64_t *head,
100 int bytes)
101{
102 int64_t head_val = atomic64_read(head);
103 int64_t new, old;
104
105 do {
106 int cycle, space;
107
108 xlog_crack_grant_head_val(head_val, &cycle, &space);
109
110 space -= bytes;
111 if (space < 0) {
112 space += log->l_logsize;
113 cycle--;
114 }
115
116 old = head_val;
117 new = xlog_assign_grant_head_val(cycle, space);
118 head_val = atomic64_cmpxchg(head, old, new);
119 } while (head_val != old);
120}
121
122static void
123xlog_grant_add_space(
124 struct xlog *log,
125 atomic64_t *head,
126 int bytes)
127{
128 int64_t head_val = atomic64_read(head);
129 int64_t new, old;
130
131 do {
132 int tmp;
133 int cycle, space;
134
135 xlog_crack_grant_head_val(head_val, &cycle, &space);
136
137 tmp = log->l_logsize - space;
138 if (tmp > bytes)
139 space += bytes;
140 else {
141 space = bytes - tmp;
142 cycle++;
143 }
144
145 old = head_val;
146 new = xlog_assign_grant_head_val(cycle, space);
147 head_val = atomic64_cmpxchg(head, old, new);
148 } while (head_val != old);
149}
150
151STATIC void
152xlog_grant_head_init(
153 struct xlog_grant_head *head)
154{
155 xlog_assign_grant_head(&head->grant, 1, 0);
156 INIT_LIST_HEAD(&head->waiters);
157 spin_lock_init(&head->lock);
158}
159
160STATIC void
161xlog_grant_head_wake_all(
162 struct xlog_grant_head *head)
163{
164 struct xlog_ticket *tic;
165
166 spin_lock(&head->lock);
167 list_for_each_entry(tic, &head->waiters, t_queue)
168 wake_up_process(tic->t_task);
169 spin_unlock(&head->lock);
170}
171
172static inline int
173xlog_ticket_reservation(
174 struct xlog *log,
175 struct xlog_grant_head *head,
176 struct xlog_ticket *tic)
177{
178 if (head == &log->l_write_head) {
179 ASSERT(tic->t_flags & XLOG_TIC_PERM_RESERV);
180 return tic->t_unit_res;
181 } else {
182 if (tic->t_flags & XLOG_TIC_PERM_RESERV)
183 return tic->t_unit_res * tic->t_cnt;
184 else
185 return tic->t_unit_res;
186 }
187}
188
189STATIC bool
190xlog_grant_head_wake(
191 struct xlog *log,
192 struct xlog_grant_head *head,
193 int *free_bytes)
194{
195 struct xlog_ticket *tic;
196 int need_bytes;
197 bool woken_task = false;
198
199 list_for_each_entry(tic, &head->waiters, t_queue) {
200
201 /*
202 * There is a chance that the size of the CIL checkpoints in
203 * progress at the last AIL push target calculation resulted in
204 * limiting the target to the log head (l_last_sync_lsn) at the
205 * time. This may not reflect where the log head is now as the
206 * CIL checkpoints may have completed.
207 *
208 * Hence when we are woken here, it may be that the head of the
209 * log that has moved rather than the tail. As the tail didn't
210 * move, there still won't be space available for the
211 * reservation we require. However, if the AIL has already
212 * pushed to the target defined by the old log head location, we
213 * will hang here waiting for something else to update the AIL
214 * push target.
215 *
216 * Therefore, if there isn't space to wake the first waiter on
217 * the grant head, we need to push the AIL again to ensure the
218 * target reflects both the current log tail and log head
219 * position before we wait for the tail to move again.
220 */
221
222 need_bytes = xlog_ticket_reservation(log, head, tic);
223 if (*free_bytes < need_bytes) {
224 if (!woken_task)
225 xlog_grant_push_ail(log, need_bytes);
226 return false;
227 }
228
229 *free_bytes -= need_bytes;
230 trace_xfs_log_grant_wake_up(log, tic);
231 wake_up_process(tic->t_task);
232 woken_task = true;
233 }
234
235 return true;
236}
237
238STATIC int
239xlog_grant_head_wait(
240 struct xlog *log,
241 struct xlog_grant_head *head,
242 struct xlog_ticket *tic,
243 int need_bytes) __releases(&head->lock)
244 __acquires(&head->lock)
245{
246 list_add_tail(&tic->t_queue, &head->waiters);
247
248 do {
249 if (XLOG_FORCED_SHUTDOWN(log))
250 goto shutdown;
251 xlog_grant_push_ail(log, need_bytes);
252
253 __set_current_state(TASK_UNINTERRUPTIBLE);
254 spin_unlock(&head->lock);
255
256 XFS_STATS_INC(log->l_mp, xs_sleep_logspace);
257
258 trace_xfs_log_grant_sleep(log, tic);
259 schedule();
260 trace_xfs_log_grant_wake(log, tic);
261
262 spin_lock(&head->lock);
263 if (XLOG_FORCED_SHUTDOWN(log))
264 goto shutdown;
265 } while (xlog_space_left(log, &head->grant) < need_bytes);
266
267 list_del_init(&tic->t_queue);
268 return 0;
269shutdown:
270 list_del_init(&tic->t_queue);
271 return -EIO;
272}
273
274/*
275 * Atomically get the log space required for a log ticket.
276 *
277 * Once a ticket gets put onto head->waiters, it will only return after the
278 * needed reservation is satisfied.
279 *
280 * This function is structured so that it has a lock free fast path. This is
281 * necessary because every new transaction reservation will come through this
282 * path. Hence any lock will be globally hot if we take it unconditionally on
283 * every pass.
284 *
285 * As tickets are only ever moved on and off head->waiters under head->lock, we
286 * only need to take that lock if we are going to add the ticket to the queue
287 * and sleep. We can avoid taking the lock if the ticket was never added to
288 * head->waiters because the t_queue list head will be empty and we hold the
289 * only reference to it so it can safely be checked unlocked.
290 */
291STATIC int
292xlog_grant_head_check(
293 struct xlog *log,
294 struct xlog_grant_head *head,
295 struct xlog_ticket *tic,
296 int *need_bytes)
297{
298 int free_bytes;
299 int error = 0;
300
301 ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
302
303 /*
304 * If there are other waiters on the queue then give them a chance at
305 * logspace before us. Wake up the first waiters, if we do not wake
306 * up all the waiters then go to sleep waiting for more free space,
307 * otherwise try to get some space for this transaction.
308 */
309 *need_bytes = xlog_ticket_reservation(log, head, tic);
310 free_bytes = xlog_space_left(log, &head->grant);
311 if (!list_empty_careful(&head->waiters)) {
312 spin_lock(&head->lock);
313 if (!xlog_grant_head_wake(log, head, &free_bytes) ||
314 free_bytes < *need_bytes) {
315 error = xlog_grant_head_wait(log, head, tic,
316 *need_bytes);
317 }
318 spin_unlock(&head->lock);
319 } else if (free_bytes < *need_bytes) {
320 spin_lock(&head->lock);
321 error = xlog_grant_head_wait(log, head, tic, *need_bytes);
322 spin_unlock(&head->lock);
323 }
324
325 return error;
326}
327
328static void
329xlog_tic_reset_res(xlog_ticket_t *tic)
330{
331 tic->t_res_num = 0;
332 tic->t_res_arr_sum = 0;
333 tic->t_res_num_ophdrs = 0;
334}
335
336static void
337xlog_tic_add_region(xlog_ticket_t *tic, uint len, uint type)
338{
339 if (tic->t_res_num == XLOG_TIC_LEN_MAX) {
340 /* add to overflow and start again */
341 tic->t_res_o_flow += tic->t_res_arr_sum;
342 tic->t_res_num = 0;
343 tic->t_res_arr_sum = 0;
344 }
345
346 tic->t_res_arr[tic->t_res_num].r_len = len;
347 tic->t_res_arr[tic->t_res_num].r_type = type;
348 tic->t_res_arr_sum += len;
349 tic->t_res_num++;
350}
351
352bool
353xfs_log_writable(
354 struct xfs_mount *mp)
355{
356 /*
357 * Do not write to the log on norecovery mounts, if the data or log
358 * devices are read-only, or if the filesystem is shutdown. Read-only
359 * mounts allow internal writes for log recovery and unmount purposes,
360 * so don't restrict that case.
361 */
362 if (mp->m_flags & XFS_MOUNT_NORECOVERY)
363 return false;
364 if (xfs_readonly_buftarg(mp->m_ddev_targp))
365 return false;
366 if (xfs_readonly_buftarg(mp->m_log->l_targ))
367 return false;
368 if (XFS_FORCED_SHUTDOWN(mp))
369 return false;
370 return true;
371}
372
373/*
374 * Replenish the byte reservation required by moving the grant write head.
375 */
376int
377xfs_log_regrant(
378 struct xfs_mount *mp,
379 struct xlog_ticket *tic)
380{
381 struct xlog *log = mp->m_log;
382 int need_bytes;
383 int error = 0;
384
385 if (XLOG_FORCED_SHUTDOWN(log))
386 return -EIO;
387
388 XFS_STATS_INC(mp, xs_try_logspace);
389
390 /*
391 * This is a new transaction on the ticket, so we need to change the
392 * transaction ID so that the next transaction has a different TID in
393 * the log. Just add one to the existing tid so that we can see chains
394 * of rolling transactions in the log easily.
395 */
396 tic->t_tid++;
397
398 xlog_grant_push_ail(log, tic->t_unit_res);
399
400 tic->t_curr_res = tic->t_unit_res;
401 xlog_tic_reset_res(tic);
402
403 if (tic->t_cnt > 0)
404 return 0;
405
406 trace_xfs_log_regrant(log, tic);
407
408 error = xlog_grant_head_check(log, &log->l_write_head, tic,
409 &need_bytes);
410 if (error)
411 goto out_error;
412
413 xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
414 trace_xfs_log_regrant_exit(log, tic);
415 xlog_verify_grant_tail(log);
416 return 0;
417
418out_error:
419 /*
420 * If we are failing, make sure the ticket doesn't have any current
421 * reservations. We don't want to add this back when the ticket/
422 * transaction gets cancelled.
423 */
424 tic->t_curr_res = 0;
425 tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
426 return error;
427}
428
429/*
430 * Reserve log space and return a ticket corresponding to the reservation.
431 *
432 * Each reservation is going to reserve extra space for a log record header.
433 * When writes happen to the on-disk log, we don't subtract the length of the
434 * log record header from any reservation. By wasting space in each
435 * reservation, we prevent over allocation problems.
436 */
437int
438xfs_log_reserve(
439 struct xfs_mount *mp,
440 int unit_bytes,
441 int cnt,
442 struct xlog_ticket **ticp,
443 uint8_t client,
444 bool permanent)
445{
446 struct xlog *log = mp->m_log;
447 struct xlog_ticket *tic;
448 int need_bytes;
449 int error = 0;
450
451 ASSERT(client == XFS_TRANSACTION || client == XFS_LOG);
452
453 if (XLOG_FORCED_SHUTDOWN(log))
454 return -EIO;
455
456 XFS_STATS_INC(mp, xs_try_logspace);
457
458 ASSERT(*ticp == NULL);
459 tic = xlog_ticket_alloc(log, unit_bytes, cnt, client, permanent);
460 *ticp = tic;
461
462 xlog_grant_push_ail(log, tic->t_cnt ? tic->t_unit_res * tic->t_cnt
463 : tic->t_unit_res);
464
465 trace_xfs_log_reserve(log, tic);
466
467 error = xlog_grant_head_check(log, &log->l_reserve_head, tic,
468 &need_bytes);
469 if (error)
470 goto out_error;
471
472 xlog_grant_add_space(log, &log->l_reserve_head.grant, need_bytes);
473 xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
474 trace_xfs_log_reserve_exit(log, tic);
475 xlog_verify_grant_tail(log);
476 return 0;
477
478out_error:
479 /*
480 * If we are failing, make sure the ticket doesn't have any current
481 * reservations. We don't want to add this back when the ticket/
482 * transaction gets cancelled.
483 */
484 tic->t_curr_res = 0;
485 tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
486 return error;
487}
488
489/*
490 * Flush iclog to disk if this is the last reference to the given iclog and the
491 * it is in the WANT_SYNC state.
492 *
493 * If the caller passes in a non-zero @old_tail_lsn and the current log tail
494 * does not match, there may be metadata on disk that must be persisted before
495 * this iclog is written. To satisfy that requirement, set the
496 * XLOG_ICL_NEED_FLUSH flag as a condition for writing this iclog with the new
497 * log tail value.
498 *
499 * If XLOG_ICL_NEED_FUA is already set on the iclog, we need to ensure that the
500 * log tail is updated correctly. NEED_FUA indicates that the iclog will be
501 * written to stable storage, and implies that a commit record is contained
502 * within the iclog. We need to ensure that the log tail does not move beyond
503 * the tail that the first commit record in the iclog ordered against, otherwise
504 * correct recovery of that checkpoint becomes dependent on future operations
505 * performed on this iclog.
506 *
507 * Hence if NEED_FUA is set and the current iclog tail lsn is empty, write the
508 * current tail into iclog. Once the iclog tail is set, future operations must
509 * not modify it, otherwise they potentially violate ordering constraints for
510 * the checkpoint commit that wrote the initial tail lsn value. The tail lsn in
511 * the iclog will get zeroed on activation of the iclog after sync, so we
512 * always capture the tail lsn on the iclog on the first NEED_FUA release
513 * regardless of the number of active reference counts on this iclog.
514 */
515
516int
517xlog_state_release_iclog(
518 struct xlog *log,
519 struct xlog_in_core *iclog,
520 xfs_lsn_t old_tail_lsn)
521{
522 xfs_lsn_t tail_lsn;
523 lockdep_assert_held(&log->l_icloglock);
524
525 trace_xlog_iclog_release(iclog, _RET_IP_);
526 if (iclog->ic_state == XLOG_STATE_IOERROR)
527 return -EIO;
528
529 /*
530 * Grabbing the current log tail needs to be atomic w.r.t. the writing
531 * of the tail LSN into the iclog so we guarantee that the log tail does
532 * not move between deciding if a cache flush is required and writing
533 * the LSN into the iclog below.
534 */
535 if (old_tail_lsn || iclog->ic_state == XLOG_STATE_WANT_SYNC) {
536 tail_lsn = xlog_assign_tail_lsn(log->l_mp);
537
538 if (old_tail_lsn && tail_lsn != old_tail_lsn)
539 iclog->ic_flags |= XLOG_ICL_NEED_FLUSH;
540
541 if ((iclog->ic_flags & XLOG_ICL_NEED_FUA) &&
542 !iclog->ic_header.h_tail_lsn)
543 iclog->ic_header.h_tail_lsn = cpu_to_be64(tail_lsn);
544 }
545
546 if (!atomic_dec_and_test(&iclog->ic_refcnt))
547 return 0;
548
549 if (iclog->ic_state != XLOG_STATE_WANT_SYNC) {
550 ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE);
551 return 0;
552 }
553
554 iclog->ic_state = XLOG_STATE_SYNCING;
555 if (!iclog->ic_header.h_tail_lsn)
556 iclog->ic_header.h_tail_lsn = cpu_to_be64(tail_lsn);
557 xlog_verify_tail_lsn(log, iclog);
558 trace_xlog_iclog_syncing(iclog, _RET_IP_);
559
560 spin_unlock(&log->l_icloglock);
561 xlog_sync(log, iclog);
562 spin_lock(&log->l_icloglock);
563 return 0;
564}
565
566/*
567 * Mount a log filesystem
568 *
569 * mp - ubiquitous xfs mount point structure
570 * log_target - buftarg of on-disk log device
571 * blk_offset - Start block # where block size is 512 bytes (BBSIZE)
572 * num_bblocks - Number of BBSIZE blocks in on-disk log
573 *
574 * Return error or zero.
575 */
576int
577xfs_log_mount(
578 xfs_mount_t *mp,
579 xfs_buftarg_t *log_target,
580 xfs_daddr_t blk_offset,
581 int num_bblks)
582{
583 bool fatal = xfs_sb_version_hascrc(&mp->m_sb);
584 int error = 0;
585 int min_logfsbs;
586
587 if (!(mp->m_flags & XFS_MOUNT_NORECOVERY)) {
588 xfs_notice(mp, "Mounting V%d Filesystem",
589 XFS_SB_VERSION_NUM(&mp->m_sb));
590 } else {
591 xfs_notice(mp,
592"Mounting V%d filesystem in no-recovery mode. Filesystem will be inconsistent.",
593 XFS_SB_VERSION_NUM(&mp->m_sb));
594 ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
595 }
596
597 mp->m_log = xlog_alloc_log(mp, log_target, blk_offset, num_bblks);
598 if (IS_ERR(mp->m_log)) {
599 error = PTR_ERR(mp->m_log);
600 goto out;
601 }
602
603 /*
604 * Validate the given log space and drop a critical message via syslog
605 * if the log size is too small that would lead to some unexpected
606 * situations in transaction log space reservation stage.
607 *
608 * Note: we can't just reject the mount if the validation fails. This
609 * would mean that people would have to downgrade their kernel just to
610 * remedy the situation as there is no way to grow the log (short of
611 * black magic surgery with xfs_db).
612 *
613 * We can, however, reject mounts for CRC format filesystems, as the
614 * mkfs binary being used to make the filesystem should never create a
615 * filesystem with a log that is too small.
616 */
617 min_logfsbs = xfs_log_calc_minimum_size(mp);
618
619 if (mp->m_sb.sb_logblocks < min_logfsbs) {
620 xfs_warn(mp,
621 "Log size %d blocks too small, minimum size is %d blocks",
622 mp->m_sb.sb_logblocks, min_logfsbs);
623 error = -EINVAL;
624 } else if (mp->m_sb.sb_logblocks > XFS_MAX_LOG_BLOCKS) {
625 xfs_warn(mp,
626 "Log size %d blocks too large, maximum size is %lld blocks",
627 mp->m_sb.sb_logblocks, XFS_MAX_LOG_BLOCKS);
628 error = -EINVAL;
629 } else if (XFS_FSB_TO_B(mp, mp->m_sb.sb_logblocks) > XFS_MAX_LOG_BYTES) {
630 xfs_warn(mp,
631 "log size %lld bytes too large, maximum size is %lld bytes",
632 XFS_FSB_TO_B(mp, mp->m_sb.sb_logblocks),
633 XFS_MAX_LOG_BYTES);
634 error = -EINVAL;
635 } else if (mp->m_sb.sb_logsunit > 1 &&
636 mp->m_sb.sb_logsunit % mp->m_sb.sb_blocksize) {
637 xfs_warn(mp,
638 "log stripe unit %u bytes must be a multiple of block size",
639 mp->m_sb.sb_logsunit);
640 error = -EINVAL;
641 fatal = true;
642 }
643 if (error) {
644 /*
645 * Log check errors are always fatal on v5; or whenever bad
646 * metadata leads to a crash.
647 */
648 if (fatal) {
649 xfs_crit(mp, "AAIEEE! Log failed size checks. Abort!");
650 ASSERT(0);
651 goto out_free_log;
652 }
653 xfs_crit(mp, "Log size out of supported range.");
654 xfs_crit(mp,
655"Continuing onwards, but if log hangs are experienced then please report this message in the bug report.");
656 }
657
658 /*
659 * Initialize the AIL now we have a log.
660 */
661 error = xfs_trans_ail_init(mp);
662 if (error) {
663 xfs_warn(mp, "AIL initialisation failed: error %d", error);
664 goto out_free_log;
665 }
666 mp->m_log->l_ailp = mp->m_ail;
667
668 /*
669 * skip log recovery on a norecovery mount. pretend it all
670 * just worked.
671 */
672 if (!(mp->m_flags & XFS_MOUNT_NORECOVERY)) {
673 int readonly = (mp->m_flags & XFS_MOUNT_RDONLY);
674
675 if (readonly)
676 mp->m_flags &= ~XFS_MOUNT_RDONLY;
677
678 error = xlog_recover(mp->m_log);
679
680 if (readonly)
681 mp->m_flags |= XFS_MOUNT_RDONLY;
682 if (error) {
683 xfs_warn(mp, "log mount/recovery failed: error %d",
684 error);
685 xlog_recover_cancel(mp->m_log);
686 goto out_destroy_ail;
687 }
688 }
689
690 error = xfs_sysfs_init(&mp->m_log->l_kobj, &xfs_log_ktype, &mp->m_kobj,
691 "log");
692 if (error)
693 goto out_destroy_ail;
694
695 /* Normal transactions can now occur */
696 mp->m_log->l_flags &= ~XLOG_ACTIVE_RECOVERY;
697
698 /*
699 * Now the log has been fully initialised and we know were our
700 * space grant counters are, we can initialise the permanent ticket
701 * needed for delayed logging to work.
702 */
703 xlog_cil_init_post_recovery(mp->m_log);
704
705 return 0;
706
707out_destroy_ail:
708 xfs_trans_ail_destroy(mp);
709out_free_log:
710 xlog_dealloc_log(mp->m_log);
711out:
712 return error;
713}
714
715/*
716 * Finish the recovery of the file system. This is separate from the
717 * xfs_log_mount() call, because it depends on the code in xfs_mountfs() to read
718 * in the root and real-time bitmap inodes between calling xfs_log_mount() and
719 * here.
720 *
721 * If we finish recovery successfully, start the background log work. If we are
722 * not doing recovery, then we have a RO filesystem and we don't need to start
723 * it.
724 */
725int
726xfs_log_mount_finish(
727 struct xfs_mount *mp)
728{
729 int error = 0;
730 bool readonly = (mp->m_flags & XFS_MOUNT_RDONLY);
731 bool recovered = mp->m_log->l_flags & XLOG_RECOVERY_NEEDED;
732
733 if (mp->m_flags & XFS_MOUNT_NORECOVERY) {
734 ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
735 return 0;
736 } else if (readonly) {
737 /* Allow unlinked processing to proceed */
738 mp->m_flags &= ~XFS_MOUNT_RDONLY;
739 }
740
741 /*
742 * During the second phase of log recovery, we need iget and
743 * iput to behave like they do for an active filesystem.
744 * xfs_fs_drop_inode needs to be able to prevent the deletion
745 * of inodes before we're done replaying log items on those
746 * inodes. Turn it off immediately after recovery finishes
747 * so that we don't leak the quota inodes if subsequent mount
748 * activities fail.
749 *
750 * We let all inodes involved in redo item processing end up on
751 * the LRU instead of being evicted immediately so that if we do
752 * something to an unlinked inode, the irele won't cause
753 * premature truncation and freeing of the inode, which results
754 * in log recovery failure. We have to evict the unreferenced
755 * lru inodes after clearing SB_ACTIVE because we don't
756 * otherwise clean up the lru if there's a subsequent failure in
757 * xfs_mountfs, which leads to us leaking the inodes if nothing
758 * else (e.g. quotacheck) references the inodes before the
759 * mount failure occurs.
760 */
761 mp->m_super->s_flags |= SB_ACTIVE;
762 error = xlog_recover_finish(mp->m_log);
763 if (!error)
764 xfs_log_work_queue(mp);
765 mp->m_super->s_flags &= ~SB_ACTIVE;
766 evict_inodes(mp->m_super);
767
768 /*
769 * Drain the buffer LRU after log recovery. This is required for v4
770 * filesystems to avoid leaving around buffers with NULL verifier ops,
771 * but we do it unconditionally to make sure we're always in a clean
772 * cache state after mount.
773 *
774 * Don't push in the error case because the AIL may have pending intents
775 * that aren't removed until recovery is cancelled.
776 */
777 if (!error && recovered) {
778 xfs_log_force(mp, XFS_LOG_SYNC);
779 xfs_ail_push_all_sync(mp->m_ail);
780 }
781 xfs_buftarg_drain(mp->m_ddev_targp);
782
783 if (readonly)
784 mp->m_flags |= XFS_MOUNT_RDONLY;
785
786 /* Make sure the log is dead if we're returning failure. */
787 ASSERT(!error || (mp->m_log->l_flags & XLOG_IO_ERROR));
788
789 return error;
790}
791
792/*
793 * The mount has failed. Cancel the recovery if it hasn't completed and destroy
794 * the log.
795 */
796void
797xfs_log_mount_cancel(
798 struct xfs_mount *mp)
799{
800 xlog_recover_cancel(mp->m_log);
801 xfs_log_unmount(mp);
802}
803
804/*
805 * Flush out the iclog to disk ensuring that device caches are flushed and
806 * the iclog hits stable storage before any completion waiters are woken.
807 */
808static inline int
809xlog_force_iclog(
810 struct xlog_in_core *iclog)
811{
812 atomic_inc(&iclog->ic_refcnt);
813 iclog->ic_flags |= XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA;
814 if (iclog->ic_state == XLOG_STATE_ACTIVE)
815 xlog_state_switch_iclogs(iclog->ic_log, iclog, 0);
816 return xlog_state_release_iclog(iclog->ic_log, iclog, 0);
817}
818
819/*
820 * Wait for the iclog and all prior iclogs to be written disk as required by the
821 * log force state machine. Waiting on ic_force_wait ensures iclog completions
822 * have been ordered and callbacks run before we are woken here, hence
823 * guaranteeing that all the iclogs up to this one are on stable storage.
824 */
825int
826xlog_wait_on_iclog(
827 struct xlog_in_core *iclog)
828 __releases(iclog->ic_log->l_icloglock)
829{
830 struct xlog *log = iclog->ic_log;
831
832 trace_xlog_iclog_wait_on(iclog, _RET_IP_);
833 if (!XLOG_FORCED_SHUTDOWN(log) &&
834 iclog->ic_state != XLOG_STATE_ACTIVE &&
835 iclog->ic_state != XLOG_STATE_DIRTY) {
836 XFS_STATS_INC(log->l_mp, xs_log_force_sleep);
837 xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
838 } else {
839 spin_unlock(&log->l_icloglock);
840 }
841
842 if (XLOG_FORCED_SHUTDOWN(log))
843 return -EIO;
844 return 0;
845}
846
847/*
848 * Write out an unmount record using the ticket provided. We have to account for
849 * the data space used in the unmount ticket as this write is not done from a
850 * transaction context that has already done the accounting for us.
851 */
852static int
853xlog_write_unmount_record(
854 struct xlog *log,
855 struct xlog_ticket *ticket)
856{
857 struct xfs_unmount_log_format ulf = {
858 .magic = XLOG_UNMOUNT_TYPE,
859 };
860 struct xfs_log_iovec reg = {
861 .i_addr = &ulf,
862 .i_len = sizeof(ulf),
863 .i_type = XLOG_REG_TYPE_UNMOUNT,
864 };
865 struct xfs_log_vec vec = {
866 .lv_niovecs = 1,
867 .lv_iovecp = ®,
868 };
869
870 /* account for space used by record data */
871 ticket->t_curr_res -= sizeof(ulf);
872
873 return xlog_write(log, &vec, ticket, NULL, NULL, XLOG_UNMOUNT_TRANS);
874}
875
876/*
877 * Mark the filesystem clean by writing an unmount record to the head of the
878 * log.
879 */
880static void
881xlog_unmount_write(
882 struct xlog *log)
883{
884 struct xfs_mount *mp = log->l_mp;
885 struct xlog_in_core *iclog;
886 struct xlog_ticket *tic = NULL;
887 int error;
888
889 error = xfs_log_reserve(mp, 600, 1, &tic, XFS_LOG, 0);
890 if (error)
891 goto out_err;
892
893 error = xlog_write_unmount_record(log, tic);
894 /*
895 * At this point, we're umounting anyway, so there's no point in
896 * transitioning log state to IOERROR. Just continue...
897 */
898out_err:
899 if (error)
900 xfs_alert(mp, "%s: unmount record failed", __func__);
901
902 spin_lock(&log->l_icloglock);
903 iclog = log->l_iclog;
904 error = xlog_force_iclog(iclog);
905 xlog_wait_on_iclog(iclog);
906
907 if (tic) {
908 trace_xfs_log_umount_write(log, tic);
909 xfs_log_ticket_ungrant(log, tic);
910 }
911}
912
913static void
914xfs_log_unmount_verify_iclog(
915 struct xlog *log)
916{
917 struct xlog_in_core *iclog = log->l_iclog;
918
919 do {
920 ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE);
921 ASSERT(iclog->ic_offset == 0);
922 } while ((iclog = iclog->ic_next) != log->l_iclog);
923}
924
925/*
926 * Unmount record used to have a string "Unmount filesystem--" in the
927 * data section where the "Un" was really a magic number (XLOG_UNMOUNT_TYPE).
928 * We just write the magic number now since that particular field isn't
929 * currently architecture converted and "Unmount" is a bit foo.
930 * As far as I know, there weren't any dependencies on the old behaviour.
931 */
932static void
933xfs_log_unmount_write(
934 struct xfs_mount *mp)
935{
936 struct xlog *log = mp->m_log;
937
938 if (!xfs_log_writable(mp))
939 return;
940
941 xfs_log_force(mp, XFS_LOG_SYNC);
942
943 if (XLOG_FORCED_SHUTDOWN(log))
944 return;
945
946 /*
947 * If we think the summary counters are bad, avoid writing the unmount
948 * record to force log recovery at next mount, after which the summary
949 * counters will be recalculated. Refer to xlog_check_unmount_rec for
950 * more details.
951 */
952 if (XFS_TEST_ERROR(xfs_fs_has_sickness(mp, XFS_SICK_FS_COUNTERS), mp,
953 XFS_ERRTAG_FORCE_SUMMARY_RECALC)) {
954 xfs_alert(mp, "%s: will fix summary counters at next mount",
955 __func__);
956 return;
957 }
958
959 xfs_log_unmount_verify_iclog(log);
960 xlog_unmount_write(log);
961}
962
963/*
964 * Empty the log for unmount/freeze.
965 *
966 * To do this, we first need to shut down the background log work so it is not
967 * trying to cover the log as we clean up. We then need to unpin all objects in
968 * the log so we can then flush them out. Once they have completed their IO and
969 * run the callbacks removing themselves from the AIL, we can cover the log.
970 */
971int
972xfs_log_quiesce(
973 struct xfs_mount *mp)
974{
975 cancel_delayed_work_sync(&mp->m_log->l_work);
976 xfs_log_force(mp, XFS_LOG_SYNC);
977
978 /*
979 * The superblock buffer is uncached and while xfs_ail_push_all_sync()
980 * will push it, xfs_buftarg_wait() will not wait for it. Further,
981 * xfs_buf_iowait() cannot be used because it was pushed with the
982 * XBF_ASYNC flag set, so we need to use a lock/unlock pair to wait for
983 * the IO to complete.
984 */
985 xfs_ail_push_all_sync(mp->m_ail);
986 xfs_buftarg_wait(mp->m_ddev_targp);
987 xfs_buf_lock(mp->m_sb_bp);
988 xfs_buf_unlock(mp->m_sb_bp);
989
990 return xfs_log_cover(mp);
991}
992
993void
994xfs_log_clean(
995 struct xfs_mount *mp)
996{
997 xfs_log_quiesce(mp);
998 xfs_log_unmount_write(mp);
999}
1000
1001/*
1002 * Shut down and release the AIL and Log.
1003 *
1004 * During unmount, we need to ensure we flush all the dirty metadata objects
1005 * from the AIL so that the log is empty before we write the unmount record to
1006 * the log. Once this is done, we can tear down the AIL and the log.
1007 */
1008void
1009xfs_log_unmount(
1010 struct xfs_mount *mp)
1011{
1012 xfs_log_clean(mp);
1013
1014 xfs_buftarg_drain(mp->m_ddev_targp);
1015
1016 xfs_trans_ail_destroy(mp);
1017
1018 xfs_sysfs_del(&mp->m_log->l_kobj);
1019
1020 xlog_dealloc_log(mp->m_log);
1021}
1022
1023void
1024xfs_log_item_init(
1025 struct xfs_mount *mp,
1026 struct xfs_log_item *item,
1027 int type,
1028 const struct xfs_item_ops *ops)
1029{
1030 item->li_mountp = mp;
1031 item->li_ailp = mp->m_ail;
1032 item->li_type = type;
1033 item->li_ops = ops;
1034 item->li_lv = NULL;
1035
1036 INIT_LIST_HEAD(&item->li_ail);
1037 INIT_LIST_HEAD(&item->li_cil);
1038 INIT_LIST_HEAD(&item->li_bio_list);
1039 INIT_LIST_HEAD(&item->li_trans);
1040}
1041
1042/*
1043 * Wake up processes waiting for log space after we have moved the log tail.
1044 */
1045void
1046xfs_log_space_wake(
1047 struct xfs_mount *mp)
1048{
1049 struct xlog *log = mp->m_log;
1050 int free_bytes;
1051
1052 if (XLOG_FORCED_SHUTDOWN(log))
1053 return;
1054
1055 if (!list_empty_careful(&log->l_write_head.waiters)) {
1056 ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
1057
1058 spin_lock(&log->l_write_head.lock);
1059 free_bytes = xlog_space_left(log, &log->l_write_head.grant);
1060 xlog_grant_head_wake(log, &log->l_write_head, &free_bytes);
1061 spin_unlock(&log->l_write_head.lock);
1062 }
1063
1064 if (!list_empty_careful(&log->l_reserve_head.waiters)) {
1065 ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
1066
1067 spin_lock(&log->l_reserve_head.lock);
1068 free_bytes = xlog_space_left(log, &log->l_reserve_head.grant);
1069 xlog_grant_head_wake(log, &log->l_reserve_head, &free_bytes);
1070 spin_unlock(&log->l_reserve_head.lock);
1071 }
1072}
1073
1074/*
1075 * Determine if we have a transaction that has gone to disk that needs to be
1076 * covered. To begin the transition to the idle state firstly the log needs to
1077 * be idle. That means the CIL, the AIL and the iclogs needs to be empty before
1078 * we start attempting to cover the log.
1079 *
1080 * Only if we are then in a state where covering is needed, the caller is
1081 * informed that dummy transactions are required to move the log into the idle
1082 * state.
1083 *
1084 * If there are any items in the AIl or CIL, then we do not want to attempt to
1085 * cover the log as we may be in a situation where there isn't log space
1086 * available to run a dummy transaction and this can lead to deadlocks when the
1087 * tail of the log is pinned by an item that is modified in the CIL. Hence
1088 * there's no point in running a dummy transaction at this point because we
1089 * can't start trying to idle the log until both the CIL and AIL are empty.
1090 */
1091static bool
1092xfs_log_need_covered(
1093 struct xfs_mount *mp)
1094{
1095 struct xlog *log = mp->m_log;
1096 bool needed = false;
1097
1098 if (!xlog_cil_empty(log))
1099 return false;
1100
1101 spin_lock(&log->l_icloglock);
1102 switch (log->l_covered_state) {
1103 case XLOG_STATE_COVER_DONE:
1104 case XLOG_STATE_COVER_DONE2:
1105 case XLOG_STATE_COVER_IDLE:
1106 break;
1107 case XLOG_STATE_COVER_NEED:
1108 case XLOG_STATE_COVER_NEED2:
1109 if (xfs_ail_min_lsn(log->l_ailp))
1110 break;
1111 if (!xlog_iclogs_empty(log))
1112 break;
1113
1114 needed = true;
1115 if (log->l_covered_state == XLOG_STATE_COVER_NEED)
1116 log->l_covered_state = XLOG_STATE_COVER_DONE;
1117 else
1118 log->l_covered_state = XLOG_STATE_COVER_DONE2;
1119 break;
1120 default:
1121 needed = true;
1122 break;
1123 }
1124 spin_unlock(&log->l_icloglock);
1125 return needed;
1126}
1127
1128/*
1129 * Explicitly cover the log. This is similar to background log covering but
1130 * intended for usage in quiesce codepaths. The caller is responsible to ensure
1131 * the log is idle and suitable for covering. The CIL, iclog buffers and AIL
1132 * must all be empty.
1133 */
1134static int
1135xfs_log_cover(
1136 struct xfs_mount *mp)
1137{
1138 int error = 0;
1139 bool need_covered;
1140
1141 ASSERT((xlog_cil_empty(mp->m_log) && xlog_iclogs_empty(mp->m_log) &&
1142 !xfs_ail_min_lsn(mp->m_log->l_ailp)) ||
1143 XFS_FORCED_SHUTDOWN(mp));
1144
1145 if (!xfs_log_writable(mp))
1146 return 0;
1147
1148 /*
1149 * xfs_log_need_covered() is not idempotent because it progresses the
1150 * state machine if the log requires covering. Therefore, we must call
1151 * this function once and use the result until we've issued an sb sync.
1152 * Do so first to make that abundantly clear.
1153 *
1154 * Fall into the covering sequence if the log needs covering or the
1155 * mount has lazy superblock accounting to sync to disk. The sb sync
1156 * used for covering accumulates the in-core counters, so covering
1157 * handles this for us.
1158 */
1159 need_covered = xfs_log_need_covered(mp);
1160 if (!need_covered && !xfs_sb_version_haslazysbcount(&mp->m_sb))
1161 return 0;
1162
1163 /*
1164 * To cover the log, commit the superblock twice (at most) in
1165 * independent checkpoints. The first serves as a reference for the
1166 * tail pointer. The sync transaction and AIL push empties the AIL and
1167 * updates the in-core tail to the LSN of the first checkpoint. The
1168 * second commit updates the on-disk tail with the in-core LSN,
1169 * covering the log. Push the AIL one more time to leave it empty, as
1170 * we found it.
1171 */
1172 do {
1173 error = xfs_sync_sb(mp, true);
1174 if (error)
1175 break;
1176 xfs_ail_push_all_sync(mp->m_ail);
1177 } while (xfs_log_need_covered(mp));
1178
1179 return error;
1180}
1181
1182/*
1183 * We may be holding the log iclog lock upon entering this routine.
1184 */
1185xfs_lsn_t
1186xlog_assign_tail_lsn_locked(
1187 struct xfs_mount *mp)
1188{
1189 struct xlog *log = mp->m_log;
1190 struct xfs_log_item *lip;
1191 xfs_lsn_t tail_lsn;
1192
1193 assert_spin_locked(&mp->m_ail->ail_lock);
1194
1195 /*
1196 * To make sure we always have a valid LSN for the log tail we keep
1197 * track of the last LSN which was committed in log->l_last_sync_lsn,
1198 * and use that when the AIL was empty.
1199 */
1200 lip = xfs_ail_min(mp->m_ail);
1201 if (lip)
1202 tail_lsn = lip->li_lsn;
1203 else
1204 tail_lsn = atomic64_read(&log->l_last_sync_lsn);
1205 trace_xfs_log_assign_tail_lsn(log, tail_lsn);
1206 atomic64_set(&log->l_tail_lsn, tail_lsn);
1207 return tail_lsn;
1208}
1209
1210xfs_lsn_t
1211xlog_assign_tail_lsn(
1212 struct xfs_mount *mp)
1213{
1214 xfs_lsn_t tail_lsn;
1215
1216 spin_lock(&mp->m_ail->ail_lock);
1217 tail_lsn = xlog_assign_tail_lsn_locked(mp);
1218 spin_unlock(&mp->m_ail->ail_lock);
1219
1220 return tail_lsn;
1221}
1222
1223/*
1224 * Return the space in the log between the tail and the head. The head
1225 * is passed in the cycle/bytes formal parms. In the special case where
1226 * the reserve head has wrapped passed the tail, this calculation is no
1227 * longer valid. In this case, just return 0 which means there is no space
1228 * in the log. This works for all places where this function is called
1229 * with the reserve head. Of course, if the write head were to ever
1230 * wrap the tail, we should blow up. Rather than catch this case here,
1231 * we depend on other ASSERTions in other parts of the code. XXXmiken
1232 *
1233 * This code also handles the case where the reservation head is behind
1234 * the tail. The details of this case are described below, but the end
1235 * result is that we return the size of the log as the amount of space left.
1236 */
1237STATIC int
1238xlog_space_left(
1239 struct xlog *log,
1240 atomic64_t *head)
1241{
1242 int free_bytes;
1243 int tail_bytes;
1244 int tail_cycle;
1245 int head_cycle;
1246 int head_bytes;
1247
1248 xlog_crack_grant_head(head, &head_cycle, &head_bytes);
1249 xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_bytes);
1250 tail_bytes = BBTOB(tail_bytes);
1251 if (tail_cycle == head_cycle && head_bytes >= tail_bytes)
1252 free_bytes = log->l_logsize - (head_bytes - tail_bytes);
1253 else if (tail_cycle + 1 < head_cycle)
1254 return 0;
1255 else if (tail_cycle < head_cycle) {
1256 ASSERT(tail_cycle == (head_cycle - 1));
1257 free_bytes = tail_bytes - head_bytes;
1258 } else {
1259 /*
1260 * The reservation head is behind the tail.
1261 * In this case we just want to return the size of the
1262 * log as the amount of space left.
1263 */
1264 xfs_alert(log->l_mp, "xlog_space_left: head behind tail");
1265 xfs_alert(log->l_mp,
1266 " tail_cycle = %d, tail_bytes = %d",
1267 tail_cycle, tail_bytes);
1268 xfs_alert(log->l_mp,
1269 " GH cycle = %d, GH bytes = %d",
1270 head_cycle, head_bytes);
1271 ASSERT(0);
1272 free_bytes = log->l_logsize;
1273 }
1274 return free_bytes;
1275}
1276
1277
1278static void
1279xlog_ioend_work(
1280 struct work_struct *work)
1281{
1282 struct xlog_in_core *iclog =
1283 container_of(work, struct xlog_in_core, ic_end_io_work);
1284 struct xlog *log = iclog->ic_log;
1285 int error;
1286
1287 error = blk_status_to_errno(iclog->ic_bio.bi_status);
1288#ifdef DEBUG
1289 /* treat writes with injected CRC errors as failed */
1290 if (iclog->ic_fail_crc)
1291 error = -EIO;
1292#endif
1293
1294 /*
1295 * Race to shutdown the filesystem if we see an error.
1296 */
1297 if (XFS_TEST_ERROR(error, log->l_mp, XFS_ERRTAG_IODONE_IOERR)) {
1298 xfs_alert(log->l_mp, "log I/O error %d", error);
1299 xfs_force_shutdown(log->l_mp, SHUTDOWN_LOG_IO_ERROR);
1300 }
1301
1302 xlog_state_done_syncing(iclog);
1303 bio_uninit(&iclog->ic_bio);
1304
1305 /*
1306 * Drop the lock to signal that we are done. Nothing references the
1307 * iclog after this, so an unmount waiting on this lock can now tear it
1308 * down safely. As such, it is unsafe to reference the iclog after the
1309 * unlock as we could race with it being freed.
1310 */
1311 up(&iclog->ic_sema);
1312}
1313
1314/*
1315 * Return size of each in-core log record buffer.
1316 *
1317 * All machines get 8 x 32kB buffers by default, unless tuned otherwise.
1318 *
1319 * If the filesystem blocksize is too large, we may need to choose a
1320 * larger size since the directory code currently logs entire blocks.
1321 */
1322STATIC void
1323xlog_get_iclog_buffer_size(
1324 struct xfs_mount *mp,
1325 struct xlog *log)
1326{
1327 if (mp->m_logbufs <= 0)
1328 mp->m_logbufs = XLOG_MAX_ICLOGS;
1329 if (mp->m_logbsize <= 0)
1330 mp->m_logbsize = XLOG_BIG_RECORD_BSIZE;
1331
1332 log->l_iclog_bufs = mp->m_logbufs;
1333 log->l_iclog_size = mp->m_logbsize;
1334
1335 /*
1336 * # headers = size / 32k - one header holds cycles from 32k of data.
1337 */
1338 log->l_iclog_heads =
1339 DIV_ROUND_UP(mp->m_logbsize, XLOG_HEADER_CYCLE_SIZE);
1340 log->l_iclog_hsize = log->l_iclog_heads << BBSHIFT;
1341}
1342
1343void
1344xfs_log_work_queue(
1345 struct xfs_mount *mp)
1346{
1347 queue_delayed_work(mp->m_sync_workqueue, &mp->m_log->l_work,
1348 msecs_to_jiffies(xfs_syncd_centisecs * 10));
1349}
1350
1351/*
1352 * Every sync period we need to unpin all items in the AIL and push them to
1353 * disk. If there is nothing dirty, then we might need to cover the log to
1354 * indicate that the filesystem is idle.
1355 */
1356static void
1357xfs_log_worker(
1358 struct work_struct *work)
1359{
1360 struct xlog *log = container_of(to_delayed_work(work),
1361 struct xlog, l_work);
1362 struct xfs_mount *mp = log->l_mp;
1363
1364 /* dgc: errors ignored - not fatal and nowhere to report them */
1365 if (xfs_fs_writable(mp, SB_FREEZE_WRITE) && xfs_log_need_covered(mp)) {
1366 /*
1367 * Dump a transaction into the log that contains no real change.
1368 * This is needed to stamp the current tail LSN into the log
1369 * during the covering operation.
1370 *
1371 * We cannot use an inode here for this - that will push dirty
1372 * state back up into the VFS and then periodic inode flushing
1373 * will prevent log covering from making progress. Hence we
1374 * synchronously log the superblock instead to ensure the
1375 * superblock is immediately unpinned and can be written back.
1376 */
1377 xfs_sync_sb(mp, true);
1378 } else
1379 xfs_log_force(mp, 0);
1380
1381 /* start pushing all the metadata that is currently dirty */
1382 xfs_ail_push_all(mp->m_ail);
1383
1384 /* queue us up again */
1385 xfs_log_work_queue(mp);
1386}
1387
1388/*
1389 * This routine initializes some of the log structure for a given mount point.
1390 * Its primary purpose is to fill in enough, so recovery can occur. However,
1391 * some other stuff may be filled in too.
1392 */
1393STATIC struct xlog *
1394xlog_alloc_log(
1395 struct xfs_mount *mp,
1396 struct xfs_buftarg *log_target,
1397 xfs_daddr_t blk_offset,
1398 int num_bblks)
1399{
1400 struct xlog *log;
1401 xlog_rec_header_t *head;
1402 xlog_in_core_t **iclogp;
1403 xlog_in_core_t *iclog, *prev_iclog=NULL;
1404 int i;
1405 int error = -ENOMEM;
1406 uint log2_size = 0;
1407
1408 log = kmem_zalloc(sizeof(struct xlog), KM_MAYFAIL);
1409 if (!log) {
1410 xfs_warn(mp, "Log allocation failed: No memory!");
1411 goto out;
1412 }
1413
1414 log->l_mp = mp;
1415 log->l_targ = log_target;
1416 log->l_logsize = BBTOB(num_bblks);
1417 log->l_logBBstart = blk_offset;
1418 log->l_logBBsize = num_bblks;
1419 log->l_covered_state = XLOG_STATE_COVER_IDLE;
1420 log->l_flags |= XLOG_ACTIVE_RECOVERY;
1421 INIT_DELAYED_WORK(&log->l_work, xfs_log_worker);
1422
1423 log->l_prev_block = -1;
1424 /* log->l_tail_lsn = 0x100000000LL; cycle = 1; current block = 0 */
1425 xlog_assign_atomic_lsn(&log->l_tail_lsn, 1, 0);
1426 xlog_assign_atomic_lsn(&log->l_last_sync_lsn, 1, 0);
1427 log->l_curr_cycle = 1; /* 0 is bad since this is initial value */
1428
1429 if (xfs_sb_version_haslogv2(&mp->m_sb) && mp->m_sb.sb_logsunit > 1)
1430 log->l_iclog_roundoff = mp->m_sb.sb_logsunit;
1431 else
1432 log->l_iclog_roundoff = BBSIZE;
1433
1434 xlog_grant_head_init(&log->l_reserve_head);
1435 xlog_grant_head_init(&log->l_write_head);
1436
1437 error = -EFSCORRUPTED;
1438 if (xfs_sb_version_hassector(&mp->m_sb)) {
1439 log2_size = mp->m_sb.sb_logsectlog;
1440 if (log2_size < BBSHIFT) {
1441 xfs_warn(mp, "Log sector size too small (0x%x < 0x%x)",
1442 log2_size, BBSHIFT);
1443 goto out_free_log;
1444 }
1445
1446 log2_size -= BBSHIFT;
1447 if (log2_size > mp->m_sectbb_log) {
1448 xfs_warn(mp, "Log sector size too large (0x%x > 0x%x)",
1449 log2_size, mp->m_sectbb_log);
1450 goto out_free_log;
1451 }
1452
1453 /* for larger sector sizes, must have v2 or external log */
1454 if (log2_size && log->l_logBBstart > 0 &&
1455 !xfs_sb_version_haslogv2(&mp->m_sb)) {
1456 xfs_warn(mp,
1457 "log sector size (0x%x) invalid for configuration.",
1458 log2_size);
1459 goto out_free_log;
1460 }
1461 }
1462 log->l_sectBBsize = 1 << log2_size;
1463
1464 xlog_get_iclog_buffer_size(mp, log);
1465
1466 spin_lock_init(&log->l_icloglock);
1467 init_waitqueue_head(&log->l_flush_wait);
1468
1469 iclogp = &log->l_iclog;
1470 /*
1471 * The amount of memory to allocate for the iclog structure is
1472 * rather funky due to the way the structure is defined. It is
1473 * done this way so that we can use different sizes for machines
1474 * with different amounts of memory. See the definition of
1475 * xlog_in_core_t in xfs_log_priv.h for details.
1476 */
1477 ASSERT(log->l_iclog_size >= 4096);
1478 for (i = 0; i < log->l_iclog_bufs; i++) {
1479 int align_mask = xfs_buftarg_dma_alignment(mp->m_logdev_targp);
1480 size_t bvec_size = howmany(log->l_iclog_size, PAGE_SIZE) *
1481 sizeof(struct bio_vec);
1482
1483 iclog = kmem_zalloc(sizeof(*iclog) + bvec_size, KM_MAYFAIL);
1484 if (!iclog)
1485 goto out_free_iclog;
1486
1487 *iclogp = iclog;
1488 iclog->ic_prev = prev_iclog;
1489 prev_iclog = iclog;
1490
1491 iclog->ic_data = kmem_alloc_io(log->l_iclog_size, align_mask,
1492 KM_MAYFAIL | KM_ZERO);
1493 if (!iclog->ic_data)
1494 goto out_free_iclog;
1495#ifdef DEBUG
1496 log->l_iclog_bak[i] = &iclog->ic_header;
1497#endif
1498 head = &iclog->ic_header;
1499 memset(head, 0, sizeof(xlog_rec_header_t));
1500 head->h_magicno = cpu_to_be32(XLOG_HEADER_MAGIC_NUM);
1501 head->h_version = cpu_to_be32(
1502 xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? 2 : 1);
1503 head->h_size = cpu_to_be32(log->l_iclog_size);
1504 /* new fields */
1505 head->h_fmt = cpu_to_be32(XLOG_FMT);
1506 memcpy(&head->h_fs_uuid, &mp->m_sb.sb_uuid, sizeof(uuid_t));
1507
1508 iclog->ic_size = log->l_iclog_size - log->l_iclog_hsize;
1509 iclog->ic_state = XLOG_STATE_ACTIVE;
1510 iclog->ic_log = log;
1511 atomic_set(&iclog->ic_refcnt, 0);
1512 INIT_LIST_HEAD(&iclog->ic_callbacks);
1513 iclog->ic_datap = (char *)iclog->ic_data + log->l_iclog_hsize;
1514
1515 init_waitqueue_head(&iclog->ic_force_wait);
1516 init_waitqueue_head(&iclog->ic_write_wait);
1517 INIT_WORK(&iclog->ic_end_io_work, xlog_ioend_work);
1518 sema_init(&iclog->ic_sema, 1);
1519
1520 iclogp = &iclog->ic_next;
1521 }
1522 *iclogp = log->l_iclog; /* complete ring */
1523 log->l_iclog->ic_prev = prev_iclog; /* re-write 1st prev ptr */
1524
1525 log->l_ioend_workqueue = alloc_workqueue("xfs-log/%s",
1526 XFS_WQFLAGS(WQ_FREEZABLE | WQ_MEM_RECLAIM |
1527 WQ_HIGHPRI),
1528 0, mp->m_super->s_id);
1529 if (!log->l_ioend_workqueue)
1530 goto out_free_iclog;
1531
1532 error = xlog_cil_init(log);
1533 if (error)
1534 goto out_destroy_workqueue;
1535 return log;
1536
1537out_destroy_workqueue:
1538 destroy_workqueue(log->l_ioend_workqueue);
1539out_free_iclog:
1540 for (iclog = log->l_iclog; iclog; iclog = prev_iclog) {
1541 prev_iclog = iclog->ic_next;
1542 kmem_free(iclog->ic_data);
1543 kmem_free(iclog);
1544 if (prev_iclog == log->l_iclog)
1545 break;
1546 }
1547out_free_log:
1548 kmem_free(log);
1549out:
1550 return ERR_PTR(error);
1551} /* xlog_alloc_log */
1552
1553/*
1554 * Write out the commit record of a transaction associated with the given
1555 * ticket to close off a running log write. Return the lsn of the commit record.
1556 */
1557int
1558xlog_commit_record(
1559 struct xlog *log,
1560 struct xlog_ticket *ticket,
1561 struct xlog_in_core **iclog,
1562 xfs_lsn_t *lsn)
1563{
1564 struct xfs_log_iovec reg = {
1565 .i_addr = NULL,
1566 .i_len = 0,
1567 .i_type = XLOG_REG_TYPE_COMMIT,
1568 };
1569 struct xfs_log_vec vec = {
1570 .lv_niovecs = 1,
1571 .lv_iovecp = ®,
1572 };
1573 int error;
1574
1575 if (XLOG_FORCED_SHUTDOWN(log))
1576 return -EIO;
1577
1578 error = xlog_write(log, &vec, ticket, lsn, iclog, XLOG_COMMIT_TRANS);
1579 if (error)
1580 xfs_force_shutdown(log->l_mp, SHUTDOWN_LOG_IO_ERROR);
1581 return error;
1582}
1583
1584/*
1585 * Compute the LSN that we'd need to push the log tail towards in order to have
1586 * (a) enough on-disk log space to log the number of bytes specified, (b) at
1587 * least 25% of the log space free, and (c) at least 256 blocks free. If the
1588 * log free space already meets all three thresholds, this function returns
1589 * NULLCOMMITLSN.
1590 */
1591xfs_lsn_t
1592xlog_grant_push_threshold(
1593 struct xlog *log,
1594 int need_bytes)
1595{
1596 xfs_lsn_t threshold_lsn = 0;
1597 xfs_lsn_t last_sync_lsn;
1598 int free_blocks;
1599 int free_bytes;
1600 int threshold_block;
1601 int threshold_cycle;
1602 int free_threshold;
1603
1604 ASSERT(BTOBB(need_bytes) < log->l_logBBsize);
1605
1606 free_bytes = xlog_space_left(log, &log->l_reserve_head.grant);
1607 free_blocks = BTOBBT(free_bytes);
1608
1609 /*
1610 * Set the threshold for the minimum number of free blocks in the
1611 * log to the maximum of what the caller needs, one quarter of the
1612 * log, and 256 blocks.
1613 */
1614 free_threshold = BTOBB(need_bytes);
1615 free_threshold = max(free_threshold, (log->l_logBBsize >> 2));
1616 free_threshold = max(free_threshold, 256);
1617 if (free_blocks >= free_threshold)
1618 return NULLCOMMITLSN;
1619
1620 xlog_crack_atomic_lsn(&log->l_tail_lsn, &threshold_cycle,
1621 &threshold_block);
1622 threshold_block += free_threshold;
1623 if (threshold_block >= log->l_logBBsize) {
1624 threshold_block -= log->l_logBBsize;
1625 threshold_cycle += 1;
1626 }
1627 threshold_lsn = xlog_assign_lsn(threshold_cycle,
1628 threshold_block);
1629 /*
1630 * Don't pass in an lsn greater than the lsn of the last
1631 * log record known to be on disk. Use a snapshot of the last sync lsn
1632 * so that it doesn't change between the compare and the set.
1633 */
1634 last_sync_lsn = atomic64_read(&log->l_last_sync_lsn);
1635 if (XFS_LSN_CMP(threshold_lsn, last_sync_lsn) > 0)
1636 threshold_lsn = last_sync_lsn;
1637
1638 return threshold_lsn;
1639}
1640
1641/*
1642 * Push the tail of the log if we need to do so to maintain the free log space
1643 * thresholds set out by xlog_grant_push_threshold. We may need to adopt a
1644 * policy which pushes on an lsn which is further along in the log once we
1645 * reach the high water mark. In this manner, we would be creating a low water
1646 * mark.
1647 */
1648STATIC void
1649xlog_grant_push_ail(
1650 struct xlog *log,
1651 int need_bytes)
1652{
1653 xfs_lsn_t threshold_lsn;
1654
1655 threshold_lsn = xlog_grant_push_threshold(log, need_bytes);
1656 if (threshold_lsn == NULLCOMMITLSN || XLOG_FORCED_SHUTDOWN(log))
1657 return;
1658
1659 /*
1660 * Get the transaction layer to kick the dirty buffers out to
1661 * disk asynchronously. No point in trying to do this if
1662 * the filesystem is shutting down.
1663 */
1664 xfs_ail_push(log->l_ailp, threshold_lsn);
1665}
1666
1667/*
1668 * Stamp cycle number in every block
1669 */
1670STATIC void
1671xlog_pack_data(
1672 struct xlog *log,
1673 struct xlog_in_core *iclog,
1674 int roundoff)
1675{
1676 int i, j, k;
1677 int size = iclog->ic_offset + roundoff;
1678 __be32 cycle_lsn;
1679 char *dp;
1680
1681 cycle_lsn = CYCLE_LSN_DISK(iclog->ic_header.h_lsn);
1682
1683 dp = iclog->ic_datap;
1684 for (i = 0; i < BTOBB(size); i++) {
1685 if (i >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE))
1686 break;
1687 iclog->ic_header.h_cycle_data[i] = *(__be32 *)dp;
1688 *(__be32 *)dp = cycle_lsn;
1689 dp += BBSIZE;
1690 }
1691
1692 if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
1693 xlog_in_core_2_t *xhdr = iclog->ic_data;
1694
1695 for ( ; i < BTOBB(size); i++) {
1696 j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
1697 k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
1698 xhdr[j].hic_xheader.xh_cycle_data[k] = *(__be32 *)dp;
1699 *(__be32 *)dp = cycle_lsn;
1700 dp += BBSIZE;
1701 }
1702
1703 for (i = 1; i < log->l_iclog_heads; i++)
1704 xhdr[i].hic_xheader.xh_cycle = cycle_lsn;
1705 }
1706}
1707
1708/*
1709 * Calculate the checksum for a log buffer.
1710 *
1711 * This is a little more complicated than it should be because the various
1712 * headers and the actual data are non-contiguous.
1713 */
1714__le32
1715xlog_cksum(
1716 struct xlog *log,
1717 struct xlog_rec_header *rhead,
1718 char *dp,
1719 int size)
1720{
1721 uint32_t crc;
1722
1723 /* first generate the crc for the record header ... */
1724 crc = xfs_start_cksum_update((char *)rhead,
1725 sizeof(struct xlog_rec_header),
1726 offsetof(struct xlog_rec_header, h_crc));
1727
1728 /* ... then for additional cycle data for v2 logs ... */
1729 if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
1730 union xlog_in_core2 *xhdr = (union xlog_in_core2 *)rhead;
1731 int i;
1732 int xheads;
1733
1734 xheads = DIV_ROUND_UP(size, XLOG_HEADER_CYCLE_SIZE);
1735
1736 for (i = 1; i < xheads; i++) {
1737 crc = crc32c(crc, &xhdr[i].hic_xheader,
1738 sizeof(struct xlog_rec_ext_header));
1739 }
1740 }
1741
1742 /* ... and finally for the payload */
1743 crc = crc32c(crc, dp, size);
1744
1745 return xfs_end_cksum(crc);
1746}
1747
1748static void
1749xlog_bio_end_io(
1750 struct bio *bio)
1751{
1752 struct xlog_in_core *iclog = bio->bi_private;
1753
1754 queue_work(iclog->ic_log->l_ioend_workqueue,
1755 &iclog->ic_end_io_work);
1756}
1757
1758static int
1759xlog_map_iclog_data(
1760 struct bio *bio,
1761 void *data,
1762 size_t count)
1763{
1764 do {
1765 struct page *page = kmem_to_page(data);
1766 unsigned int off = offset_in_page(data);
1767 size_t len = min_t(size_t, count, PAGE_SIZE - off);
1768
1769 if (bio_add_page(bio, page, len, off) != len)
1770 return -EIO;
1771
1772 data += len;
1773 count -= len;
1774 } while (count);
1775
1776 return 0;
1777}
1778
1779STATIC void
1780xlog_write_iclog(
1781 struct xlog *log,
1782 struct xlog_in_core *iclog,
1783 uint64_t bno,
1784 unsigned int count)
1785{
1786 ASSERT(bno < log->l_logBBsize);
1787 trace_xlog_iclog_write(iclog, _RET_IP_);
1788
1789 /*
1790 * We lock the iclogbufs here so that we can serialise against I/O
1791 * completion during unmount. We might be processing a shutdown
1792 * triggered during unmount, and that can occur asynchronously to the
1793 * unmount thread, and hence we need to ensure that completes before
1794 * tearing down the iclogbufs. Hence we need to hold the buffer lock
1795 * across the log IO to archieve that.
1796 */
1797 down(&iclog->ic_sema);
1798 if (unlikely(iclog->ic_state == XLOG_STATE_IOERROR)) {
1799 /*
1800 * It would seem logical to return EIO here, but we rely on
1801 * the log state machine to propagate I/O errors instead of
1802 * doing it here. We kick of the state machine and unlock
1803 * the buffer manually, the code needs to be kept in sync
1804 * with the I/O completion path.
1805 */
1806 xlog_state_done_syncing(iclog);
1807 up(&iclog->ic_sema);
1808 return;
1809 }
1810
1811 bio_init(&iclog->ic_bio, iclog->ic_bvec, howmany(count, PAGE_SIZE));
1812 bio_set_dev(&iclog->ic_bio, log->l_targ->bt_bdev);
1813 iclog->ic_bio.bi_iter.bi_sector = log->l_logBBstart + bno;
1814 iclog->ic_bio.bi_end_io = xlog_bio_end_io;
1815 iclog->ic_bio.bi_private = iclog;
1816
1817 /*
1818 * We use REQ_SYNC | REQ_IDLE here to tell the block layer the are more
1819 * IOs coming immediately after this one. This prevents the block layer
1820 * writeback throttle from throttling log writes behind background
1821 * metadata writeback and causing priority inversions.
1822 */
1823 iclog->ic_bio.bi_opf = REQ_OP_WRITE | REQ_META | REQ_SYNC | REQ_IDLE;
1824 if (iclog->ic_flags & XLOG_ICL_NEED_FLUSH) {
1825 iclog->ic_bio.bi_opf |= REQ_PREFLUSH;
1826 /*
1827 * For external log devices, we also need to flush the data
1828 * device cache first to ensure all metadata writeback covered
1829 * by the LSN in this iclog is on stable storage. This is slow,
1830 * but it *must* complete before we issue the external log IO.
1831 */
1832 if (log->l_targ != log->l_mp->m_ddev_targp)
1833 blkdev_issue_flush(log->l_mp->m_ddev_targp->bt_bdev);
1834 }
1835 if (iclog->ic_flags & XLOG_ICL_NEED_FUA)
1836 iclog->ic_bio.bi_opf |= REQ_FUA;
1837
1838 iclog->ic_flags &= ~(XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA);
1839
1840 if (xlog_map_iclog_data(&iclog->ic_bio, iclog->ic_data, count)) {
1841 xfs_force_shutdown(log->l_mp, SHUTDOWN_LOG_IO_ERROR);
1842 return;
1843 }
1844 if (is_vmalloc_addr(iclog->ic_data))
1845 flush_kernel_vmap_range(iclog->ic_data, count);
1846
1847 /*
1848 * If this log buffer would straddle the end of the log we will have
1849 * to split it up into two bios, so that we can continue at the start.
1850 */
1851 if (bno + BTOBB(count) > log->l_logBBsize) {
1852 struct bio *split;
1853
1854 split = bio_split(&iclog->ic_bio, log->l_logBBsize - bno,
1855 GFP_NOIO, &fs_bio_set);
1856 bio_chain(split, &iclog->ic_bio);
1857 submit_bio(split);
1858
1859 /* restart at logical offset zero for the remainder */
1860 iclog->ic_bio.bi_iter.bi_sector = log->l_logBBstart;
1861 }
1862
1863 submit_bio(&iclog->ic_bio);
1864}
1865
1866/*
1867 * We need to bump cycle number for the part of the iclog that is
1868 * written to the start of the log. Watch out for the header magic
1869 * number case, though.
1870 */
1871static void
1872xlog_split_iclog(
1873 struct xlog *log,
1874 void *data,
1875 uint64_t bno,
1876 unsigned int count)
1877{
1878 unsigned int split_offset = BBTOB(log->l_logBBsize - bno);
1879 unsigned int i;
1880
1881 for (i = split_offset; i < count; i += BBSIZE) {
1882 uint32_t cycle = get_unaligned_be32(data + i);
1883
1884 if (++cycle == XLOG_HEADER_MAGIC_NUM)
1885 cycle++;
1886 put_unaligned_be32(cycle, data + i);
1887 }
1888}
1889
1890static int
1891xlog_calc_iclog_size(
1892 struct xlog *log,
1893 struct xlog_in_core *iclog,
1894 uint32_t *roundoff)
1895{
1896 uint32_t count_init, count;
1897
1898 /* Add for LR header */
1899 count_init = log->l_iclog_hsize + iclog->ic_offset;
1900 count = roundup(count_init, log->l_iclog_roundoff);
1901
1902 *roundoff = count - count_init;
1903
1904 ASSERT(count >= count_init);
1905 ASSERT(*roundoff < log->l_iclog_roundoff);
1906 return count;
1907}
1908
1909/*
1910 * Flush out the in-core log (iclog) to the on-disk log in an asynchronous
1911 * fashion. Previously, we should have moved the current iclog
1912 * ptr in the log to point to the next available iclog. This allows further
1913 * write to continue while this code syncs out an iclog ready to go.
1914 * Before an in-core log can be written out, the data section must be scanned
1915 * to save away the 1st word of each BBSIZE block into the header. We replace
1916 * it with the current cycle count. Each BBSIZE block is tagged with the
1917 * cycle count because there in an implicit assumption that drives will
1918 * guarantee that entire 512 byte blocks get written at once. In other words,
1919 * we can't have part of a 512 byte block written and part not written. By
1920 * tagging each block, we will know which blocks are valid when recovering
1921 * after an unclean shutdown.
1922 *
1923 * This routine is single threaded on the iclog. No other thread can be in
1924 * this routine with the same iclog. Changing contents of iclog can there-
1925 * fore be done without grabbing the state machine lock. Updating the global
1926 * log will require grabbing the lock though.
1927 *
1928 * The entire log manager uses a logical block numbering scheme. Only
1929 * xlog_write_iclog knows about the fact that the log may not start with
1930 * block zero on a given device.
1931 */
1932STATIC void
1933xlog_sync(
1934 struct xlog *log,
1935 struct xlog_in_core *iclog)
1936{
1937 unsigned int count; /* byte count of bwrite */
1938 unsigned int roundoff; /* roundoff to BB or stripe */
1939 uint64_t bno;
1940 unsigned int size;
1941
1942 ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
1943 trace_xlog_iclog_sync(iclog, _RET_IP_);
1944
1945 count = xlog_calc_iclog_size(log, iclog, &roundoff);
1946
1947 /* move grant heads by roundoff in sync */
1948 xlog_grant_add_space(log, &log->l_reserve_head.grant, roundoff);
1949 xlog_grant_add_space(log, &log->l_write_head.grant, roundoff);
1950
1951 /* put cycle number in every block */
1952 xlog_pack_data(log, iclog, roundoff);
1953
1954 /* real byte length */
1955 size = iclog->ic_offset;
1956 if (xfs_sb_version_haslogv2(&log->l_mp->m_sb))
1957 size += roundoff;
1958 iclog->ic_header.h_len = cpu_to_be32(size);
1959
1960 XFS_STATS_INC(log->l_mp, xs_log_writes);
1961 XFS_STATS_ADD(log->l_mp, xs_log_blocks, BTOBB(count));
1962
1963 bno = BLOCK_LSN(be64_to_cpu(iclog->ic_header.h_lsn));
1964
1965 /* Do we need to split this write into 2 parts? */
1966 if (bno + BTOBB(count) > log->l_logBBsize)
1967 xlog_split_iclog(log, &iclog->ic_header, bno, count);
1968
1969 /* calculcate the checksum */
1970 iclog->ic_header.h_crc = xlog_cksum(log, &iclog->ic_header,
1971 iclog->ic_datap, size);
1972 /*
1973 * Intentionally corrupt the log record CRC based on the error injection
1974 * frequency, if defined. This facilitates testing log recovery in the
1975 * event of torn writes. Hence, set the IOABORT state to abort the log
1976 * write on I/O completion and shutdown the fs. The subsequent mount
1977 * detects the bad CRC and attempts to recover.
1978 */
1979#ifdef DEBUG
1980 if (XFS_TEST_ERROR(false, log->l_mp, XFS_ERRTAG_LOG_BAD_CRC)) {
1981 iclog->ic_header.h_crc &= cpu_to_le32(0xAAAAAAAA);
1982 iclog->ic_fail_crc = true;
1983 xfs_warn(log->l_mp,
1984 "Intentionally corrupted log record at LSN 0x%llx. Shutdown imminent.",
1985 be64_to_cpu(iclog->ic_header.h_lsn));
1986 }
1987#endif
1988 xlog_verify_iclog(log, iclog, count);
1989 xlog_write_iclog(log, iclog, bno, count);
1990}
1991
1992/*
1993 * Deallocate a log structure
1994 */
1995STATIC void
1996xlog_dealloc_log(
1997 struct xlog *log)
1998{
1999 xlog_in_core_t *iclog, *next_iclog;
2000 int i;
2001
2002 xlog_cil_destroy(log);
2003
2004 /*
2005 * Cycle all the iclogbuf locks to make sure all log IO completion
2006 * is done before we tear down these buffers.
2007 */
2008 iclog = log->l_iclog;
2009 for (i = 0; i < log->l_iclog_bufs; i++) {
2010 down(&iclog->ic_sema);
2011 up(&iclog->ic_sema);
2012 iclog = iclog->ic_next;
2013 }
2014
2015 iclog = log->l_iclog;
2016 for (i = 0; i < log->l_iclog_bufs; i++) {
2017 next_iclog = iclog->ic_next;
2018 kmem_free(iclog->ic_data);
2019 kmem_free(iclog);
2020 iclog = next_iclog;
2021 }
2022
2023 log->l_mp->m_log = NULL;
2024 destroy_workqueue(log->l_ioend_workqueue);
2025 kmem_free(log);
2026}
2027
2028/*
2029 * Update counters atomically now that memcpy is done.
2030 */
2031static inline void
2032xlog_state_finish_copy(
2033 struct xlog *log,
2034 struct xlog_in_core *iclog,
2035 int record_cnt,
2036 int copy_bytes)
2037{
2038 lockdep_assert_held(&log->l_icloglock);
2039
2040 be32_add_cpu(&iclog->ic_header.h_num_logops, record_cnt);
2041 iclog->ic_offset += copy_bytes;
2042}
2043
2044/*
2045 * print out info relating to regions written which consume
2046 * the reservation
2047 */
2048void
2049xlog_print_tic_res(
2050 struct xfs_mount *mp,
2051 struct xlog_ticket *ticket)
2052{
2053 uint i;
2054 uint ophdr_spc = ticket->t_res_num_ophdrs * (uint)sizeof(xlog_op_header_t);
2055
2056 /* match with XLOG_REG_TYPE_* in xfs_log.h */
2057#define REG_TYPE_STR(type, str) [XLOG_REG_TYPE_##type] = str
2058 static char *res_type_str[] = {
2059 REG_TYPE_STR(BFORMAT, "bformat"),
2060 REG_TYPE_STR(BCHUNK, "bchunk"),
2061 REG_TYPE_STR(EFI_FORMAT, "efi_format"),
2062 REG_TYPE_STR(EFD_FORMAT, "efd_format"),
2063 REG_TYPE_STR(IFORMAT, "iformat"),
2064 REG_TYPE_STR(ICORE, "icore"),
2065 REG_TYPE_STR(IEXT, "iext"),
2066 REG_TYPE_STR(IBROOT, "ibroot"),
2067 REG_TYPE_STR(ILOCAL, "ilocal"),
2068 REG_TYPE_STR(IATTR_EXT, "iattr_ext"),
2069 REG_TYPE_STR(IATTR_BROOT, "iattr_broot"),
2070 REG_TYPE_STR(IATTR_LOCAL, "iattr_local"),
2071 REG_TYPE_STR(QFORMAT, "qformat"),
2072 REG_TYPE_STR(DQUOT, "dquot"),
2073 REG_TYPE_STR(QUOTAOFF, "quotaoff"),
2074 REG_TYPE_STR(LRHEADER, "LR header"),
2075 REG_TYPE_STR(UNMOUNT, "unmount"),
2076 REG_TYPE_STR(COMMIT, "commit"),
2077 REG_TYPE_STR(TRANSHDR, "trans header"),
2078 REG_TYPE_STR(ICREATE, "inode create"),
2079 REG_TYPE_STR(RUI_FORMAT, "rui_format"),
2080 REG_TYPE_STR(RUD_FORMAT, "rud_format"),
2081 REG_TYPE_STR(CUI_FORMAT, "cui_format"),
2082 REG_TYPE_STR(CUD_FORMAT, "cud_format"),
2083 REG_TYPE_STR(BUI_FORMAT, "bui_format"),
2084 REG_TYPE_STR(BUD_FORMAT, "bud_format"),
2085 };
2086 BUILD_BUG_ON(ARRAY_SIZE(res_type_str) != XLOG_REG_TYPE_MAX + 1);
2087#undef REG_TYPE_STR
2088
2089 xfs_warn(mp, "ticket reservation summary:");
2090 xfs_warn(mp, " unit res = %d bytes",
2091 ticket->t_unit_res);
2092 xfs_warn(mp, " current res = %d bytes",
2093 ticket->t_curr_res);
2094 xfs_warn(mp, " total reg = %u bytes (o/flow = %u bytes)",
2095 ticket->t_res_arr_sum, ticket->t_res_o_flow);
2096 xfs_warn(mp, " ophdrs = %u (ophdr space = %u bytes)",
2097 ticket->t_res_num_ophdrs, ophdr_spc);
2098 xfs_warn(mp, " ophdr + reg = %u bytes",
2099 ticket->t_res_arr_sum + ticket->t_res_o_flow + ophdr_spc);
2100 xfs_warn(mp, " num regions = %u",
2101 ticket->t_res_num);
2102
2103 for (i = 0; i < ticket->t_res_num; i++) {
2104 uint r_type = ticket->t_res_arr[i].r_type;
2105 xfs_warn(mp, "region[%u]: %s - %u bytes", i,
2106 ((r_type <= 0 || r_type > XLOG_REG_TYPE_MAX) ?
2107 "bad-rtype" : res_type_str[r_type]),
2108 ticket->t_res_arr[i].r_len);
2109 }
2110}
2111
2112/*
2113 * Print a summary of the transaction.
2114 */
2115void
2116xlog_print_trans(
2117 struct xfs_trans *tp)
2118{
2119 struct xfs_mount *mp = tp->t_mountp;
2120 struct xfs_log_item *lip;
2121
2122 /* dump core transaction and ticket info */
2123 xfs_warn(mp, "transaction summary:");
2124 xfs_warn(mp, " log res = %d", tp->t_log_res);
2125 xfs_warn(mp, " log count = %d", tp->t_log_count);
2126 xfs_warn(mp, " flags = 0x%x", tp->t_flags);
2127
2128 xlog_print_tic_res(mp, tp->t_ticket);
2129
2130 /* dump each log item */
2131 list_for_each_entry(lip, &tp->t_items, li_trans) {
2132 struct xfs_log_vec *lv = lip->li_lv;
2133 struct xfs_log_iovec *vec;
2134 int i;
2135
2136 xfs_warn(mp, "log item: ");
2137 xfs_warn(mp, " type = 0x%x", lip->li_type);
2138 xfs_warn(mp, " flags = 0x%lx", lip->li_flags);
2139 if (!lv)
2140 continue;
2141 xfs_warn(mp, " niovecs = %d", lv->lv_niovecs);
2142 xfs_warn(mp, " size = %d", lv->lv_size);
2143 xfs_warn(mp, " bytes = %d", lv->lv_bytes);
2144 xfs_warn(mp, " buf len = %d", lv->lv_buf_len);
2145
2146 /* dump each iovec for the log item */
2147 vec = lv->lv_iovecp;
2148 for (i = 0; i < lv->lv_niovecs; i++) {
2149 int dumplen = min(vec->i_len, 32);
2150
2151 xfs_warn(mp, " iovec[%d]", i);
2152 xfs_warn(mp, " type = 0x%x", vec->i_type);
2153 xfs_warn(mp, " len = %d", vec->i_len);
2154 xfs_warn(mp, " first %d bytes of iovec[%d]:", dumplen, i);
2155 xfs_hex_dump(vec->i_addr, dumplen);
2156
2157 vec++;
2158 }
2159 }
2160}
2161
2162/*
2163 * Calculate the potential space needed by the log vector. We may need a start
2164 * record, and each region gets its own struct xlog_op_header and may need to be
2165 * double word aligned.
2166 */
2167static int
2168xlog_write_calc_vec_length(
2169 struct xlog_ticket *ticket,
2170 struct xfs_log_vec *log_vector,
2171 uint optype)
2172{
2173 struct xfs_log_vec *lv;
2174 int headers = 0;
2175 int len = 0;
2176 int i;
2177
2178 if (optype & XLOG_START_TRANS)
2179 headers++;
2180
2181 for (lv = log_vector; lv; lv = lv->lv_next) {
2182 /* we don't write ordered log vectors */
2183 if (lv->lv_buf_len == XFS_LOG_VEC_ORDERED)
2184 continue;
2185
2186 headers += lv->lv_niovecs;
2187
2188 for (i = 0; i < lv->lv_niovecs; i++) {
2189 struct xfs_log_iovec *vecp = &lv->lv_iovecp[i];
2190
2191 len += vecp->i_len;
2192 xlog_tic_add_region(ticket, vecp->i_len, vecp->i_type);
2193 }
2194 }
2195
2196 ticket->t_res_num_ophdrs += headers;
2197 len += headers * sizeof(struct xlog_op_header);
2198
2199 return len;
2200}
2201
2202static void
2203xlog_write_start_rec(
2204 struct xlog_op_header *ophdr,
2205 struct xlog_ticket *ticket)
2206{
2207 ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
2208 ophdr->oh_clientid = ticket->t_clientid;
2209 ophdr->oh_len = 0;
2210 ophdr->oh_flags = XLOG_START_TRANS;
2211 ophdr->oh_res2 = 0;
2212}
2213
2214static xlog_op_header_t *
2215xlog_write_setup_ophdr(
2216 struct xlog *log,
2217 struct xlog_op_header *ophdr,
2218 struct xlog_ticket *ticket,
2219 uint flags)
2220{
2221 ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
2222 ophdr->oh_clientid = ticket->t_clientid;
2223 ophdr->oh_res2 = 0;
2224
2225 /* are we copying a commit or unmount record? */
2226 ophdr->oh_flags = flags;
2227
2228 /*
2229 * We've seen logs corrupted with bad transaction client ids. This
2230 * makes sure that XFS doesn't generate them on. Turn this into an EIO
2231 * and shut down the filesystem.
2232 */
2233 switch (ophdr->oh_clientid) {
2234 case XFS_TRANSACTION:
2235 case XFS_VOLUME:
2236 case XFS_LOG:
2237 break;
2238 default:
2239 xfs_warn(log->l_mp,
2240 "Bad XFS transaction clientid 0x%x in ticket "PTR_FMT,
2241 ophdr->oh_clientid, ticket);
2242 return NULL;
2243 }
2244
2245 return ophdr;
2246}
2247
2248/*
2249 * Set up the parameters of the region copy into the log. This has
2250 * to handle region write split across multiple log buffers - this
2251 * state is kept external to this function so that this code can
2252 * be written in an obvious, self documenting manner.
2253 */
2254static int
2255xlog_write_setup_copy(
2256 struct xlog_ticket *ticket,
2257 struct xlog_op_header *ophdr,
2258 int space_available,
2259 int space_required,
2260 int *copy_off,
2261 int *copy_len,
2262 int *last_was_partial_copy,
2263 int *bytes_consumed)
2264{
2265 int still_to_copy;
2266
2267 still_to_copy = space_required - *bytes_consumed;
2268 *copy_off = *bytes_consumed;
2269
2270 if (still_to_copy <= space_available) {
2271 /* write of region completes here */
2272 *copy_len = still_to_copy;
2273 ophdr->oh_len = cpu_to_be32(*copy_len);
2274 if (*last_was_partial_copy)
2275 ophdr->oh_flags |= (XLOG_END_TRANS|XLOG_WAS_CONT_TRANS);
2276 *last_was_partial_copy = 0;
2277 *bytes_consumed = 0;
2278 return 0;
2279 }
2280
2281 /* partial write of region, needs extra log op header reservation */
2282 *copy_len = space_available;
2283 ophdr->oh_len = cpu_to_be32(*copy_len);
2284 ophdr->oh_flags |= XLOG_CONTINUE_TRANS;
2285 if (*last_was_partial_copy)
2286 ophdr->oh_flags |= XLOG_WAS_CONT_TRANS;
2287 *bytes_consumed += *copy_len;
2288 (*last_was_partial_copy)++;
2289
2290 /* account for new log op header */
2291 ticket->t_curr_res -= sizeof(struct xlog_op_header);
2292 ticket->t_res_num_ophdrs++;
2293
2294 return sizeof(struct xlog_op_header);
2295}
2296
2297static int
2298xlog_write_copy_finish(
2299 struct xlog *log,
2300 struct xlog_in_core *iclog,
2301 uint flags,
2302 int *record_cnt,
2303 int *data_cnt,
2304 int *partial_copy,
2305 int *partial_copy_len,
2306 int log_offset,
2307 struct xlog_in_core **commit_iclog)
2308{
2309 int error;
2310
2311 if (*partial_copy) {
2312 /*
2313 * This iclog has already been marked WANT_SYNC by
2314 * xlog_state_get_iclog_space.
2315 */
2316 spin_lock(&log->l_icloglock);
2317 xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
2318 *record_cnt = 0;
2319 *data_cnt = 0;
2320 goto release_iclog;
2321 }
2322
2323 *partial_copy = 0;
2324 *partial_copy_len = 0;
2325
2326 if (iclog->ic_size - log_offset <= sizeof(xlog_op_header_t)) {
2327 /* no more space in this iclog - push it. */
2328 spin_lock(&log->l_icloglock);
2329 xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
2330 *record_cnt = 0;
2331 *data_cnt = 0;
2332
2333 if (iclog->ic_state == XLOG_STATE_ACTIVE)
2334 xlog_state_switch_iclogs(log, iclog, 0);
2335 else
2336 ASSERT(iclog->ic_state == XLOG_STATE_WANT_SYNC ||
2337 iclog->ic_state == XLOG_STATE_IOERROR);
2338 if (!commit_iclog)
2339 goto release_iclog;
2340 spin_unlock(&log->l_icloglock);
2341 ASSERT(flags & XLOG_COMMIT_TRANS);
2342 *commit_iclog = iclog;
2343 }
2344
2345 return 0;
2346
2347release_iclog:
2348 error = xlog_state_release_iclog(log, iclog, 0);
2349 spin_unlock(&log->l_icloglock);
2350 return error;
2351}
2352
2353/*
2354 * Write some region out to in-core log
2355 *
2356 * This will be called when writing externally provided regions or when
2357 * writing out a commit record for a given transaction.
2358 *
2359 * General algorithm:
2360 * 1. Find total length of this write. This may include adding to the
2361 * lengths passed in.
2362 * 2. Check whether we violate the tickets reservation.
2363 * 3. While writing to this iclog
2364 * A. Reserve as much space in this iclog as can get
2365 * B. If this is first write, save away start lsn
2366 * C. While writing this region:
2367 * 1. If first write of transaction, write start record
2368 * 2. Write log operation header (header per region)
2369 * 3. Find out if we can fit entire region into this iclog
2370 * 4. Potentially, verify destination memcpy ptr
2371 * 5. Memcpy (partial) region
2372 * 6. If partial copy, release iclog; otherwise, continue
2373 * copying more regions into current iclog
2374 * 4. Mark want sync bit (in simulation mode)
2375 * 5. Release iclog for potential flush to on-disk log.
2376 *
2377 * ERRORS:
2378 * 1. Panic if reservation is overrun. This should never happen since
2379 * reservation amounts are generated internal to the filesystem.
2380 * NOTES:
2381 * 1. Tickets are single threaded data structures.
2382 * 2. The XLOG_END_TRANS & XLOG_CONTINUE_TRANS flags are passed down to the
2383 * syncing routine. When a single log_write region needs to span
2384 * multiple in-core logs, the XLOG_CONTINUE_TRANS bit should be set
2385 * on all log operation writes which don't contain the end of the
2386 * region. The XLOG_END_TRANS bit is used for the in-core log
2387 * operation which contains the end of the continued log_write region.
2388 * 3. When xlog_state_get_iclog_space() grabs the rest of the current iclog,
2389 * we don't really know exactly how much space will be used. As a result,
2390 * we don't update ic_offset until the end when we know exactly how many
2391 * bytes have been written out.
2392 */
2393int
2394xlog_write(
2395 struct xlog *log,
2396 struct xfs_log_vec *log_vector,
2397 struct xlog_ticket *ticket,
2398 xfs_lsn_t *start_lsn,
2399 struct xlog_in_core **commit_iclog,
2400 uint optype)
2401{
2402 struct xlog_in_core *iclog = NULL;
2403 struct xfs_log_vec *lv = log_vector;
2404 struct xfs_log_iovec *vecp = lv->lv_iovecp;
2405 int index = 0;
2406 int len;
2407 int partial_copy = 0;
2408 int partial_copy_len = 0;
2409 int contwr = 0;
2410 int record_cnt = 0;
2411 int data_cnt = 0;
2412 int error = 0;
2413
2414 /*
2415 * If this is a commit or unmount transaction, we don't need a start
2416 * record to be written. We do, however, have to account for the
2417 * commit or unmount header that gets written. Hence we always have
2418 * to account for an extra xlog_op_header here.
2419 */
2420 ticket->t_curr_res -= sizeof(struct xlog_op_header);
2421 if (ticket->t_curr_res < 0) {
2422 xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
2423 "ctx ticket reservation ran out. Need to up reservation");
2424 xlog_print_tic_res(log->l_mp, ticket);
2425 xfs_force_shutdown(log->l_mp, SHUTDOWN_LOG_IO_ERROR);
2426 }
2427
2428 len = xlog_write_calc_vec_length(ticket, log_vector, optype);
2429 if (start_lsn)
2430 *start_lsn = 0;
2431 while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) {
2432 void *ptr;
2433 int log_offset;
2434
2435 error = xlog_state_get_iclog_space(log, len, &iclog, ticket,
2436 &contwr, &log_offset);
2437 if (error)
2438 return error;
2439
2440 ASSERT(log_offset <= iclog->ic_size - 1);
2441 ptr = iclog->ic_datap + log_offset;
2442
2443 /* Start_lsn is the first lsn written to. */
2444 if (start_lsn && !*start_lsn)
2445 *start_lsn = be64_to_cpu(iclog->ic_header.h_lsn);
2446
2447 /*
2448 * This loop writes out as many regions as can fit in the amount
2449 * of space which was allocated by xlog_state_get_iclog_space().
2450 */
2451 while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) {
2452 struct xfs_log_iovec *reg;
2453 struct xlog_op_header *ophdr;
2454 int copy_len;
2455 int copy_off;
2456 bool ordered = false;
2457 bool wrote_start_rec = false;
2458
2459 /* ordered log vectors have no regions to write */
2460 if (lv->lv_buf_len == XFS_LOG_VEC_ORDERED) {
2461 ASSERT(lv->lv_niovecs == 0);
2462 ordered = true;
2463 goto next_lv;
2464 }
2465
2466 reg = &vecp[index];
2467 ASSERT(reg->i_len % sizeof(int32_t) == 0);
2468 ASSERT((unsigned long)ptr % sizeof(int32_t) == 0);
2469
2470 /*
2471 * Before we start formatting log vectors, we need to
2472 * write a start record. Only do this for the first
2473 * iclog we write to.
2474 */
2475 if (optype & XLOG_START_TRANS) {
2476 xlog_write_start_rec(ptr, ticket);
2477 xlog_write_adv_cnt(&ptr, &len, &log_offset,
2478 sizeof(struct xlog_op_header));
2479 optype &= ~XLOG_START_TRANS;
2480 wrote_start_rec = true;
2481 }
2482
2483 ophdr = xlog_write_setup_ophdr(log, ptr, ticket, optype);
2484 if (!ophdr)
2485 return -EIO;
2486
2487 xlog_write_adv_cnt(&ptr, &len, &log_offset,
2488 sizeof(struct xlog_op_header));
2489
2490 len += xlog_write_setup_copy(ticket, ophdr,
2491 iclog->ic_size-log_offset,
2492 reg->i_len,
2493 ©_off, ©_len,
2494 &partial_copy,
2495 &partial_copy_len);
2496 xlog_verify_dest_ptr(log, ptr);
2497
2498 /*
2499 * Copy region.
2500 *
2501 * Unmount records just log an opheader, so can have
2502 * empty payloads with no data region to copy. Hence we
2503 * only copy the payload if the vector says it has data
2504 * to copy.
2505 */
2506 ASSERT(copy_len >= 0);
2507 if (copy_len > 0) {
2508 memcpy(ptr, reg->i_addr + copy_off, copy_len);
2509 xlog_write_adv_cnt(&ptr, &len, &log_offset,
2510 copy_len);
2511 }
2512 copy_len += sizeof(struct xlog_op_header);
2513 record_cnt++;
2514 if (wrote_start_rec) {
2515 copy_len += sizeof(struct xlog_op_header);
2516 record_cnt++;
2517 }
2518 data_cnt += contwr ? copy_len : 0;
2519
2520 error = xlog_write_copy_finish(log, iclog, optype,
2521 &record_cnt, &data_cnt,
2522 &partial_copy,
2523 &partial_copy_len,
2524 log_offset,
2525 commit_iclog);
2526 if (error)
2527 return error;
2528
2529 /*
2530 * if we had a partial copy, we need to get more iclog
2531 * space but we don't want to increment the region
2532 * index because there is still more is this region to
2533 * write.
2534 *
2535 * If we completed writing this region, and we flushed
2536 * the iclog (indicated by resetting of the record
2537 * count), then we also need to get more log space. If
2538 * this was the last record, though, we are done and
2539 * can just return.
2540 */
2541 if (partial_copy)
2542 break;
2543
2544 if (++index == lv->lv_niovecs) {
2545next_lv:
2546 lv = lv->lv_next;
2547 index = 0;
2548 if (lv)
2549 vecp = lv->lv_iovecp;
2550 }
2551 if (record_cnt == 0 && !ordered) {
2552 if (!lv)
2553 return 0;
2554 break;
2555 }
2556 }
2557 }
2558
2559 ASSERT(len == 0);
2560
2561 spin_lock(&log->l_icloglock);
2562 xlog_state_finish_copy(log, iclog, record_cnt, data_cnt);
2563 if (commit_iclog) {
2564 ASSERT(optype & XLOG_COMMIT_TRANS);
2565 *commit_iclog = iclog;
2566 } else {
2567 error = xlog_state_release_iclog(log, iclog, 0);
2568 }
2569 spin_unlock(&log->l_icloglock);
2570
2571 return error;
2572}
2573
2574static void
2575xlog_state_activate_iclog(
2576 struct xlog_in_core *iclog,
2577 int *iclogs_changed)
2578{
2579 ASSERT(list_empty_careful(&iclog->ic_callbacks));
2580 trace_xlog_iclog_activate(iclog, _RET_IP_);
2581
2582 /*
2583 * If the number of ops in this iclog indicate it just contains the
2584 * dummy transaction, we can change state into IDLE (the second time
2585 * around). Otherwise we should change the state into NEED a dummy.
2586 * We don't need to cover the dummy.
2587 */
2588 if (*iclogs_changed == 0 &&
2589 iclog->ic_header.h_num_logops == cpu_to_be32(XLOG_COVER_OPS)) {
2590 *iclogs_changed = 1;
2591 } else {
2592 /*
2593 * We have two dirty iclogs so start over. This could also be
2594 * num of ops indicating this is not the dummy going out.
2595 */
2596 *iclogs_changed = 2;
2597 }
2598
2599 iclog->ic_state = XLOG_STATE_ACTIVE;
2600 iclog->ic_offset = 0;
2601 iclog->ic_header.h_num_logops = 0;
2602 memset(iclog->ic_header.h_cycle_data, 0,
2603 sizeof(iclog->ic_header.h_cycle_data));
2604 iclog->ic_header.h_lsn = 0;
2605 iclog->ic_header.h_tail_lsn = 0;
2606}
2607
2608/*
2609 * Loop through all iclogs and mark all iclogs currently marked DIRTY as
2610 * ACTIVE after iclog I/O has completed.
2611 */
2612static void
2613xlog_state_activate_iclogs(
2614 struct xlog *log,
2615 int *iclogs_changed)
2616{
2617 struct xlog_in_core *iclog = log->l_iclog;
2618
2619 do {
2620 if (iclog->ic_state == XLOG_STATE_DIRTY)
2621 xlog_state_activate_iclog(iclog, iclogs_changed);
2622 /*
2623 * The ordering of marking iclogs ACTIVE must be maintained, so
2624 * an iclog doesn't become ACTIVE beyond one that is SYNCING.
2625 */
2626 else if (iclog->ic_state != XLOG_STATE_ACTIVE)
2627 break;
2628 } while ((iclog = iclog->ic_next) != log->l_iclog);
2629}
2630
2631static int
2632xlog_covered_state(
2633 int prev_state,
2634 int iclogs_changed)
2635{
2636 /*
2637 * We go to NEED for any non-covering writes. We go to NEED2 if we just
2638 * wrote the first covering record (DONE). We go to IDLE if we just
2639 * wrote the second covering record (DONE2) and remain in IDLE until a
2640 * non-covering write occurs.
2641 */
2642 switch (prev_state) {
2643 case XLOG_STATE_COVER_IDLE:
2644 if (iclogs_changed == 1)
2645 return XLOG_STATE_COVER_IDLE;
2646 fallthrough;
2647 case XLOG_STATE_COVER_NEED:
2648 case XLOG_STATE_COVER_NEED2:
2649 break;
2650 case XLOG_STATE_COVER_DONE:
2651 if (iclogs_changed == 1)
2652 return XLOG_STATE_COVER_NEED2;
2653 break;
2654 case XLOG_STATE_COVER_DONE2:
2655 if (iclogs_changed == 1)
2656 return XLOG_STATE_COVER_IDLE;
2657 break;
2658 default:
2659 ASSERT(0);
2660 }
2661
2662 return XLOG_STATE_COVER_NEED;
2663}
2664
2665STATIC void
2666xlog_state_clean_iclog(
2667 struct xlog *log,
2668 struct xlog_in_core *dirty_iclog)
2669{
2670 int iclogs_changed = 0;
2671
2672 trace_xlog_iclog_clean(dirty_iclog, _RET_IP_);
2673
2674 dirty_iclog->ic_state = XLOG_STATE_DIRTY;
2675
2676 xlog_state_activate_iclogs(log, &iclogs_changed);
2677 wake_up_all(&dirty_iclog->ic_force_wait);
2678
2679 if (iclogs_changed) {
2680 log->l_covered_state = xlog_covered_state(log->l_covered_state,
2681 iclogs_changed);
2682 }
2683}
2684
2685STATIC xfs_lsn_t
2686xlog_get_lowest_lsn(
2687 struct xlog *log)
2688{
2689 struct xlog_in_core *iclog = log->l_iclog;
2690 xfs_lsn_t lowest_lsn = 0, lsn;
2691
2692 do {
2693 if (iclog->ic_state == XLOG_STATE_ACTIVE ||
2694 iclog->ic_state == XLOG_STATE_DIRTY)
2695 continue;
2696
2697 lsn = be64_to_cpu(iclog->ic_header.h_lsn);
2698 if ((lsn && !lowest_lsn) || XFS_LSN_CMP(lsn, lowest_lsn) < 0)
2699 lowest_lsn = lsn;
2700 } while ((iclog = iclog->ic_next) != log->l_iclog);
2701
2702 return lowest_lsn;
2703}
2704
2705/*
2706 * Completion of a iclog IO does not imply that a transaction has completed, as
2707 * transactions can be large enough to span many iclogs. We cannot change the
2708 * tail of the log half way through a transaction as this may be the only
2709 * transaction in the log and moving the tail to point to the middle of it
2710 * will prevent recovery from finding the start of the transaction. Hence we
2711 * should only update the last_sync_lsn if this iclog contains transaction
2712 * completion callbacks on it.
2713 *
2714 * We have to do this before we drop the icloglock to ensure we are the only one
2715 * that can update it.
2716 *
2717 * If we are moving the last_sync_lsn forwards, we also need to ensure we kick
2718 * the reservation grant head pushing. This is due to the fact that the push
2719 * target is bound by the current last_sync_lsn value. Hence if we have a large
2720 * amount of log space bound up in this committing transaction then the
2721 * last_sync_lsn value may be the limiting factor preventing tail pushing from
2722 * freeing space in the log. Hence once we've updated the last_sync_lsn we
2723 * should push the AIL to ensure the push target (and hence the grant head) is
2724 * no longer bound by the old log head location and can move forwards and make
2725 * progress again.
2726 */
2727static void
2728xlog_state_set_callback(
2729 struct xlog *log,
2730 struct xlog_in_core *iclog,
2731 xfs_lsn_t header_lsn)
2732{
2733 trace_xlog_iclog_callback(iclog, _RET_IP_);
2734 iclog->ic_state = XLOG_STATE_CALLBACK;
2735
2736 ASSERT(XFS_LSN_CMP(atomic64_read(&log->l_last_sync_lsn),
2737 header_lsn) <= 0);
2738
2739 if (list_empty_careful(&iclog->ic_callbacks))
2740 return;
2741
2742 atomic64_set(&log->l_last_sync_lsn, header_lsn);
2743 xlog_grant_push_ail(log, 0);
2744}
2745
2746/*
2747 * Return true if we need to stop processing, false to continue to the next
2748 * iclog. The caller will need to run callbacks if the iclog is returned in the
2749 * XLOG_STATE_CALLBACK state.
2750 */
2751static bool
2752xlog_state_iodone_process_iclog(
2753 struct xlog *log,
2754 struct xlog_in_core *iclog,
2755 bool *ioerror)
2756{
2757 xfs_lsn_t lowest_lsn;
2758 xfs_lsn_t header_lsn;
2759
2760 switch (iclog->ic_state) {
2761 case XLOG_STATE_ACTIVE:
2762 case XLOG_STATE_DIRTY:
2763 /*
2764 * Skip all iclogs in the ACTIVE & DIRTY states:
2765 */
2766 return false;
2767 case XLOG_STATE_IOERROR:
2768 /*
2769 * Between marking a filesystem SHUTDOWN and stopping the log,
2770 * we do flush all iclogs to disk (if there wasn't a log I/O
2771 * error). So, we do want things to go smoothly in case of just
2772 * a SHUTDOWN w/o a LOG_IO_ERROR.
2773 */
2774 *ioerror = true;
2775 return false;
2776 case XLOG_STATE_DONE_SYNC:
2777 /*
2778 * Now that we have an iclog that is in the DONE_SYNC state, do
2779 * one more check here to see if we have chased our tail around.
2780 * If this is not the lowest lsn iclog, then we will leave it
2781 * for another completion to process.
2782 */
2783 header_lsn = be64_to_cpu(iclog->ic_header.h_lsn);
2784 lowest_lsn = xlog_get_lowest_lsn(log);
2785 if (lowest_lsn && XFS_LSN_CMP(lowest_lsn, header_lsn) < 0)
2786 return false;
2787 xlog_state_set_callback(log, iclog, header_lsn);
2788 return false;
2789 default:
2790 /*
2791 * Can only perform callbacks in order. Since this iclog is not
2792 * in the DONE_SYNC state, we skip the rest and just try to
2793 * clean up.
2794 */
2795 return true;
2796 }
2797}
2798
2799STATIC void
2800xlog_state_do_callback(
2801 struct xlog *log)
2802{
2803 struct xlog_in_core *iclog;
2804 struct xlog_in_core *first_iclog;
2805 bool cycled_icloglock;
2806 bool ioerror;
2807 int flushcnt = 0;
2808 int repeats = 0;
2809
2810 spin_lock(&log->l_icloglock);
2811 do {
2812 /*
2813 * Scan all iclogs starting with the one pointed to by the
2814 * log. Reset this starting point each time the log is
2815 * unlocked (during callbacks).
2816 *
2817 * Keep looping through iclogs until one full pass is made
2818 * without running any callbacks.
2819 */
2820 first_iclog = log->l_iclog;
2821 iclog = log->l_iclog;
2822 cycled_icloglock = false;
2823 ioerror = false;
2824 repeats++;
2825
2826 do {
2827 LIST_HEAD(cb_list);
2828
2829 if (xlog_state_iodone_process_iclog(log, iclog,
2830 &ioerror))
2831 break;
2832
2833 if (iclog->ic_state != XLOG_STATE_CALLBACK &&
2834 iclog->ic_state != XLOG_STATE_IOERROR) {
2835 iclog = iclog->ic_next;
2836 continue;
2837 }
2838 list_splice_init(&iclog->ic_callbacks, &cb_list);
2839 spin_unlock(&log->l_icloglock);
2840
2841 trace_xlog_iclog_callbacks_start(iclog, _RET_IP_);
2842 xlog_cil_process_committed(&cb_list);
2843 trace_xlog_iclog_callbacks_done(iclog, _RET_IP_);
2844 cycled_icloglock = true;
2845
2846 spin_lock(&log->l_icloglock);
2847 if (XLOG_FORCED_SHUTDOWN(log))
2848 wake_up_all(&iclog->ic_force_wait);
2849 else
2850 xlog_state_clean_iclog(log, iclog);
2851 iclog = iclog->ic_next;
2852 } while (first_iclog != iclog);
2853
2854 if (repeats > 5000) {
2855 flushcnt += repeats;
2856 repeats = 0;
2857 xfs_warn(log->l_mp,
2858 "%s: possible infinite loop (%d iterations)",
2859 __func__, flushcnt);
2860 }
2861 } while (!ioerror && cycled_icloglock);
2862
2863 if (log->l_iclog->ic_state == XLOG_STATE_ACTIVE ||
2864 log->l_iclog->ic_state == XLOG_STATE_IOERROR)
2865 wake_up_all(&log->l_flush_wait);
2866
2867 spin_unlock(&log->l_icloglock);
2868}
2869
2870
2871/*
2872 * Finish transitioning this iclog to the dirty state.
2873 *
2874 * Make sure that we completely execute this routine only when this is
2875 * the last call to the iclog. There is a good chance that iclog flushes,
2876 * when we reach the end of the physical log, get turned into 2 separate
2877 * calls to bwrite. Hence, one iclog flush could generate two calls to this
2878 * routine. By using the reference count bwritecnt, we guarantee that only
2879 * the second completion goes through.
2880 *
2881 * Callbacks could take time, so they are done outside the scope of the
2882 * global state machine log lock.
2883 */
2884STATIC void
2885xlog_state_done_syncing(
2886 struct xlog_in_core *iclog)
2887{
2888 struct xlog *log = iclog->ic_log;
2889
2890 spin_lock(&log->l_icloglock);
2891 ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
2892 trace_xlog_iclog_sync_done(iclog, _RET_IP_);
2893
2894 /*
2895 * If we got an error, either on the first buffer, or in the case of
2896 * split log writes, on the second, we shut down the file system and
2897 * no iclogs should ever be attempted to be written to disk again.
2898 */
2899 if (!XLOG_FORCED_SHUTDOWN(log)) {
2900 ASSERT(iclog->ic_state == XLOG_STATE_SYNCING);
2901 iclog->ic_state = XLOG_STATE_DONE_SYNC;
2902 }
2903
2904 /*
2905 * Someone could be sleeping prior to writing out the next
2906 * iclog buffer, we wake them all, one will get to do the
2907 * I/O, the others get to wait for the result.
2908 */
2909 wake_up_all(&iclog->ic_write_wait);
2910 spin_unlock(&log->l_icloglock);
2911 xlog_state_do_callback(log);
2912}
2913
2914/*
2915 * If the head of the in-core log ring is not (ACTIVE or DIRTY), then we must
2916 * sleep. We wait on the flush queue on the head iclog as that should be
2917 * the first iclog to complete flushing. Hence if all iclogs are syncing,
2918 * we will wait here and all new writes will sleep until a sync completes.
2919 *
2920 * The in-core logs are used in a circular fashion. They are not used
2921 * out-of-order even when an iclog past the head is free.
2922 *
2923 * return:
2924 * * log_offset where xlog_write() can start writing into the in-core
2925 * log's data space.
2926 * * in-core log pointer to which xlog_write() should write.
2927 * * boolean indicating this is a continued write to an in-core log.
2928 * If this is the last write, then the in-core log's offset field
2929 * needs to be incremented, depending on the amount of data which
2930 * is copied.
2931 */
2932STATIC int
2933xlog_state_get_iclog_space(
2934 struct xlog *log,
2935 int len,
2936 struct xlog_in_core **iclogp,
2937 struct xlog_ticket *ticket,
2938 int *continued_write,
2939 int *logoffsetp)
2940{
2941 int log_offset;
2942 xlog_rec_header_t *head;
2943 xlog_in_core_t *iclog;
2944
2945restart:
2946 spin_lock(&log->l_icloglock);
2947 if (XLOG_FORCED_SHUTDOWN(log)) {
2948 spin_unlock(&log->l_icloglock);
2949 return -EIO;
2950 }
2951
2952 iclog = log->l_iclog;
2953 if (iclog->ic_state != XLOG_STATE_ACTIVE) {
2954 XFS_STATS_INC(log->l_mp, xs_log_noiclogs);
2955
2956 /* Wait for log writes to have flushed */
2957 xlog_wait(&log->l_flush_wait, &log->l_icloglock);
2958 goto restart;
2959 }
2960
2961 head = &iclog->ic_header;
2962
2963 atomic_inc(&iclog->ic_refcnt); /* prevents sync */
2964 log_offset = iclog->ic_offset;
2965
2966 trace_xlog_iclog_get_space(iclog, _RET_IP_);
2967
2968 /* On the 1st write to an iclog, figure out lsn. This works
2969 * if iclogs marked XLOG_STATE_WANT_SYNC always write out what they are
2970 * committing to. If the offset is set, that's how many blocks
2971 * must be written.
2972 */
2973 if (log_offset == 0) {
2974 ticket->t_curr_res -= log->l_iclog_hsize;
2975 xlog_tic_add_region(ticket,
2976 log->l_iclog_hsize,
2977 XLOG_REG_TYPE_LRHEADER);
2978 head->h_cycle = cpu_to_be32(log->l_curr_cycle);
2979 head->h_lsn = cpu_to_be64(
2980 xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block));
2981 ASSERT(log->l_curr_block >= 0);
2982 }
2983
2984 /* If there is enough room to write everything, then do it. Otherwise,
2985 * claim the rest of the region and make sure the XLOG_STATE_WANT_SYNC
2986 * bit is on, so this will get flushed out. Don't update ic_offset
2987 * until you know exactly how many bytes get copied. Therefore, wait
2988 * until later to update ic_offset.
2989 *
2990 * xlog_write() algorithm assumes that at least 2 xlog_op_header_t's
2991 * can fit into remaining data section.
2992 */
2993 if (iclog->ic_size - iclog->ic_offset < 2*sizeof(xlog_op_header_t)) {
2994 int error = 0;
2995
2996 xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
2997
2998 /*
2999 * If we are the only one writing to this iclog, sync it to
3000 * disk. We need to do an atomic compare and decrement here to
3001 * avoid racing with concurrent atomic_dec_and_lock() calls in
3002 * xlog_state_release_iclog() when there is more than one
3003 * reference to the iclog.
3004 */
3005 if (!atomic_add_unless(&iclog->ic_refcnt, -1, 1))
3006 error = xlog_state_release_iclog(log, iclog, 0);
3007 spin_unlock(&log->l_icloglock);
3008 if (error)
3009 return error;
3010 goto restart;
3011 }
3012
3013 /* Do we have enough room to write the full amount in the remainder
3014 * of this iclog? Or must we continue a write on the next iclog and
3015 * mark this iclog as completely taken? In the case where we switch
3016 * iclogs (to mark it taken), this particular iclog will release/sync
3017 * to disk in xlog_write().
3018 */
3019 if (len <= iclog->ic_size - iclog->ic_offset) {
3020 *continued_write = 0;
3021 iclog->ic_offset += len;
3022 } else {
3023 *continued_write = 1;
3024 xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
3025 }
3026 *iclogp = iclog;
3027
3028 ASSERT(iclog->ic_offset <= iclog->ic_size);
3029 spin_unlock(&log->l_icloglock);
3030
3031 *logoffsetp = log_offset;
3032 return 0;
3033}
3034
3035/*
3036 * The first cnt-1 times a ticket goes through here we don't need to move the
3037 * grant write head because the permanent reservation has reserved cnt times the
3038 * unit amount. Release part of current permanent unit reservation and reset
3039 * current reservation to be one units worth. Also move grant reservation head
3040 * forward.
3041 */
3042void
3043xfs_log_ticket_regrant(
3044 struct xlog *log,
3045 struct xlog_ticket *ticket)
3046{
3047 trace_xfs_log_ticket_regrant(log, ticket);
3048
3049 if (ticket->t_cnt > 0)
3050 ticket->t_cnt--;
3051
3052 xlog_grant_sub_space(log, &log->l_reserve_head.grant,
3053 ticket->t_curr_res);
3054 xlog_grant_sub_space(log, &log->l_write_head.grant,
3055 ticket->t_curr_res);
3056 ticket->t_curr_res = ticket->t_unit_res;
3057 xlog_tic_reset_res(ticket);
3058
3059 trace_xfs_log_ticket_regrant_sub(log, ticket);
3060
3061 /* just return if we still have some of the pre-reserved space */
3062 if (!ticket->t_cnt) {
3063 xlog_grant_add_space(log, &log->l_reserve_head.grant,
3064 ticket->t_unit_res);
3065 trace_xfs_log_ticket_regrant_exit(log, ticket);
3066
3067 ticket->t_curr_res = ticket->t_unit_res;
3068 xlog_tic_reset_res(ticket);
3069 }
3070
3071 xfs_log_ticket_put(ticket);
3072}
3073
3074/*
3075 * Give back the space left from a reservation.
3076 *
3077 * All the information we need to make a correct determination of space left
3078 * is present. For non-permanent reservations, things are quite easy. The
3079 * count should have been decremented to zero. We only need to deal with the
3080 * space remaining in the current reservation part of the ticket. If the
3081 * ticket contains a permanent reservation, there may be left over space which
3082 * needs to be released. A count of N means that N-1 refills of the current
3083 * reservation can be done before we need to ask for more space. The first
3084 * one goes to fill up the first current reservation. Once we run out of
3085 * space, the count will stay at zero and the only space remaining will be
3086 * in the current reservation field.
3087 */
3088void
3089xfs_log_ticket_ungrant(
3090 struct xlog *log,
3091 struct xlog_ticket *ticket)
3092{
3093 int bytes;
3094
3095 trace_xfs_log_ticket_ungrant(log, ticket);
3096
3097 if (ticket->t_cnt > 0)
3098 ticket->t_cnt--;
3099
3100 trace_xfs_log_ticket_ungrant_sub(log, ticket);
3101
3102 /*
3103 * If this is a permanent reservation ticket, we may be able to free
3104 * up more space based on the remaining count.
3105 */
3106 bytes = ticket->t_curr_res;
3107 if (ticket->t_cnt > 0) {
3108 ASSERT(ticket->t_flags & XLOG_TIC_PERM_RESERV);
3109 bytes += ticket->t_unit_res*ticket->t_cnt;
3110 }
3111
3112 xlog_grant_sub_space(log, &log->l_reserve_head.grant, bytes);
3113 xlog_grant_sub_space(log, &log->l_write_head.grant, bytes);
3114
3115 trace_xfs_log_ticket_ungrant_exit(log, ticket);
3116
3117 xfs_log_space_wake(log->l_mp);
3118 xfs_log_ticket_put(ticket);
3119}
3120
3121/*
3122 * This routine will mark the current iclog in the ring as WANT_SYNC and move
3123 * the current iclog pointer to the next iclog in the ring.
3124 */
3125STATIC void
3126xlog_state_switch_iclogs(
3127 struct xlog *log,
3128 struct xlog_in_core *iclog,
3129 int eventual_size)
3130{
3131 ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE);
3132 assert_spin_locked(&log->l_icloglock);
3133 trace_xlog_iclog_switch(iclog, _RET_IP_);
3134
3135 if (!eventual_size)
3136 eventual_size = iclog->ic_offset;
3137 iclog->ic_state = XLOG_STATE_WANT_SYNC;
3138 iclog->ic_header.h_prev_block = cpu_to_be32(log->l_prev_block);
3139 log->l_prev_block = log->l_curr_block;
3140 log->l_prev_cycle = log->l_curr_cycle;
3141
3142 /* roll log?: ic_offset changed later */
3143 log->l_curr_block += BTOBB(eventual_size)+BTOBB(log->l_iclog_hsize);
3144
3145 /* Round up to next log-sunit */
3146 if (log->l_iclog_roundoff > BBSIZE) {
3147 uint32_t sunit_bb = BTOBB(log->l_iclog_roundoff);
3148 log->l_curr_block = roundup(log->l_curr_block, sunit_bb);
3149 }
3150
3151 if (log->l_curr_block >= log->l_logBBsize) {
3152 /*
3153 * Rewind the current block before the cycle is bumped to make
3154 * sure that the combined LSN never transiently moves forward
3155 * when the log wraps to the next cycle. This is to support the
3156 * unlocked sample of these fields from xlog_valid_lsn(). Most
3157 * other cases should acquire l_icloglock.
3158 */
3159 log->l_curr_block -= log->l_logBBsize;
3160 ASSERT(log->l_curr_block >= 0);
3161 smp_wmb();
3162 log->l_curr_cycle++;
3163 if (log->l_curr_cycle == XLOG_HEADER_MAGIC_NUM)
3164 log->l_curr_cycle++;
3165 }
3166 ASSERT(iclog == log->l_iclog);
3167 log->l_iclog = iclog->ic_next;
3168}
3169
3170/*
3171 * Force the iclog to disk and check if the iclog has been completed before
3172 * xlog_force_iclog() returns. This can happen on synchronous (e.g.
3173 * pmem) or fast async storage because we drop the icloglock to issue the IO.
3174 * If completion has already occurred, tell the caller so that it can avoid an
3175 * unnecessary wait on the iclog.
3176 */
3177static int
3178xlog_force_and_check_iclog(
3179 struct xlog_in_core *iclog,
3180 bool *completed)
3181{
3182 xfs_lsn_t lsn = be64_to_cpu(iclog->ic_header.h_lsn);
3183 int error;
3184
3185 *completed = false;
3186 error = xlog_force_iclog(iclog);
3187 if (error)
3188 return error;
3189
3190 /*
3191 * If the iclog has already been completed and reused the header LSN
3192 * will have been rewritten by completion
3193 */
3194 if (be64_to_cpu(iclog->ic_header.h_lsn) != lsn)
3195 *completed = true;
3196 return 0;
3197}
3198
3199/*
3200 * Write out all data in the in-core log as of this exact moment in time.
3201 *
3202 * Data may be written to the in-core log during this call. However,
3203 * we don't guarantee this data will be written out. A change from past
3204 * implementation means this routine will *not* write out zero length LRs.
3205 *
3206 * Basically, we try and perform an intelligent scan of the in-core logs.
3207 * If we determine there is no flushable data, we just return. There is no
3208 * flushable data if:
3209 *
3210 * 1. the current iclog is active and has no data; the previous iclog
3211 * is in the active or dirty state.
3212 * 2. the current iclog is drity, and the previous iclog is in the
3213 * active or dirty state.
3214 *
3215 * We may sleep if:
3216 *
3217 * 1. the current iclog is not in the active nor dirty state.
3218 * 2. the current iclog dirty, and the previous iclog is not in the
3219 * active nor dirty state.
3220 * 3. the current iclog is active, and there is another thread writing
3221 * to this particular iclog.
3222 * 4. a) the current iclog is active and has no other writers
3223 * b) when we return from flushing out this iclog, it is still
3224 * not in the active nor dirty state.
3225 */
3226int
3227xfs_log_force(
3228 struct xfs_mount *mp,
3229 uint flags)
3230{
3231 struct xlog *log = mp->m_log;
3232 struct xlog_in_core *iclog;
3233
3234 XFS_STATS_INC(mp, xs_log_force);
3235 trace_xfs_log_force(mp, 0, _RET_IP_);
3236
3237 xlog_cil_force(log);
3238
3239 spin_lock(&log->l_icloglock);
3240 iclog = log->l_iclog;
3241 if (iclog->ic_state == XLOG_STATE_IOERROR)
3242 goto out_error;
3243
3244 trace_xlog_iclog_force(iclog, _RET_IP_);
3245
3246 if (iclog->ic_state == XLOG_STATE_DIRTY ||
3247 (iclog->ic_state == XLOG_STATE_ACTIVE &&
3248 atomic_read(&iclog->ic_refcnt) == 0 && iclog->ic_offset == 0)) {
3249 /*
3250 * If the head is dirty or (active and empty), then we need to
3251 * look at the previous iclog.
3252 *
3253 * If the previous iclog is active or dirty we are done. There
3254 * is nothing to sync out. Otherwise, we attach ourselves to the
3255 * previous iclog and go to sleep.
3256 */
3257 iclog = iclog->ic_prev;
3258 } else if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3259 if (atomic_read(&iclog->ic_refcnt) == 0) {
3260 /* We have exclusive access to this iclog. */
3261 bool completed;
3262
3263 if (xlog_force_and_check_iclog(iclog, &completed))
3264 goto out_error;
3265
3266 if (completed)
3267 goto out_unlock;
3268 } else {
3269 /*
3270 * Someone else is still writing to this iclog, so we
3271 * need to ensure that when they release the iclog it
3272 * gets synced immediately as we may be waiting on it.
3273 */
3274 xlog_state_switch_iclogs(log, iclog, 0);
3275 }
3276 }
3277
3278 /*
3279 * The iclog we are about to wait on may contain the checkpoint pushed
3280 * by the above xlog_cil_force() call, but it may not have been pushed
3281 * to disk yet. Like the ACTIVE case above, we need to make sure caches
3282 * are flushed when this iclog is written.
3283 */
3284 if (iclog->ic_state == XLOG_STATE_WANT_SYNC)
3285 iclog->ic_flags |= XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA;
3286
3287 if (flags & XFS_LOG_SYNC)
3288 return xlog_wait_on_iclog(iclog);
3289out_unlock:
3290 spin_unlock(&log->l_icloglock);
3291 return 0;
3292out_error:
3293 spin_unlock(&log->l_icloglock);
3294 return -EIO;
3295}
3296
3297static int
3298xlog_force_lsn(
3299 struct xlog *log,
3300 xfs_lsn_t lsn,
3301 uint flags,
3302 int *log_flushed,
3303 bool already_slept)
3304{
3305 struct xlog_in_core *iclog;
3306 bool completed;
3307
3308 spin_lock(&log->l_icloglock);
3309 iclog = log->l_iclog;
3310 if (iclog->ic_state == XLOG_STATE_IOERROR)
3311 goto out_error;
3312
3313 while (be64_to_cpu(iclog->ic_header.h_lsn) != lsn) {
3314 trace_xlog_iclog_force_lsn(iclog, _RET_IP_);
3315 iclog = iclog->ic_next;
3316 if (iclog == log->l_iclog)
3317 goto out_unlock;
3318 }
3319
3320 switch (iclog->ic_state) {
3321 case XLOG_STATE_ACTIVE:
3322 /*
3323 * We sleep here if we haven't already slept (e.g. this is the
3324 * first time we've looked at the correct iclog buf) and the
3325 * buffer before us is going to be sync'ed. The reason for this
3326 * is that if we are doing sync transactions here, by waiting
3327 * for the previous I/O to complete, we can allow a few more
3328 * transactions into this iclog before we close it down.
3329 *
3330 * Otherwise, we mark the buffer WANT_SYNC, and bump up the
3331 * refcnt so we can release the log (which drops the ref count).
3332 * The state switch keeps new transaction commits from using
3333 * this buffer. When the current commits finish writing into
3334 * the buffer, the refcount will drop to zero and the buffer
3335 * will go out then.
3336 */
3337 if (!already_slept &&
3338 (iclog->ic_prev->ic_state == XLOG_STATE_WANT_SYNC ||
3339 iclog->ic_prev->ic_state == XLOG_STATE_SYNCING)) {
3340 xlog_wait(&iclog->ic_prev->ic_write_wait,
3341 &log->l_icloglock);
3342 return -EAGAIN;
3343 }
3344 if (xlog_force_and_check_iclog(iclog, &completed))
3345 goto out_error;
3346 if (log_flushed)
3347 *log_flushed = 1;
3348 if (completed)
3349 goto out_unlock;
3350 break;
3351 case XLOG_STATE_WANT_SYNC:
3352 /*
3353 * This iclog may contain the checkpoint pushed by the
3354 * xlog_cil_force_seq() call, but there are other writers still
3355 * accessing it so it hasn't been pushed to disk yet. Like the
3356 * ACTIVE case above, we need to make sure caches are flushed
3357 * when this iclog is written.
3358 */
3359 iclog->ic_flags |= XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA;
3360 break;
3361 default:
3362 /*
3363 * The entire checkpoint was written by the CIL force and is on
3364 * its way to disk already. It will be stable when it
3365 * completes, so we don't need to manipulate caches here at all.
3366 * We just need to wait for completion if necessary.
3367 */
3368 break;
3369 }
3370
3371 if (flags & XFS_LOG_SYNC)
3372 return xlog_wait_on_iclog(iclog);
3373out_unlock:
3374 spin_unlock(&log->l_icloglock);
3375 return 0;
3376out_error:
3377 spin_unlock(&log->l_icloglock);
3378 return -EIO;
3379}
3380
3381/*
3382 * Force the in-core log to disk for a specific LSN.
3383 *
3384 * Find in-core log with lsn.
3385 * If it is in the DIRTY state, just return.
3386 * If it is in the ACTIVE state, move the in-core log into the WANT_SYNC
3387 * state and go to sleep or return.
3388 * If it is in any other state, go to sleep or return.
3389 *
3390 * Synchronous forces are implemented with a wait queue. All callers trying
3391 * to force a given lsn to disk must wait on the queue attached to the
3392 * specific in-core log. When given in-core log finally completes its write
3393 * to disk, that thread will wake up all threads waiting on the queue.
3394 */
3395int
3396xfs_log_force_seq(
3397 struct xfs_mount *mp,
3398 xfs_csn_t seq,
3399 uint flags,
3400 int *log_flushed)
3401{
3402 struct xlog *log = mp->m_log;
3403 xfs_lsn_t lsn;
3404 int ret;
3405 ASSERT(seq != 0);
3406
3407 XFS_STATS_INC(mp, xs_log_force);
3408 trace_xfs_log_force(mp, seq, _RET_IP_);
3409
3410 lsn = xlog_cil_force_seq(log, seq);
3411 if (lsn == NULLCOMMITLSN)
3412 return 0;
3413
3414 ret = xlog_force_lsn(log, lsn, flags, log_flushed, false);
3415 if (ret == -EAGAIN) {
3416 XFS_STATS_INC(mp, xs_log_force_sleep);
3417 ret = xlog_force_lsn(log, lsn, flags, log_flushed, true);
3418 }
3419 return ret;
3420}
3421
3422/*
3423 * Free a used ticket when its refcount falls to zero.
3424 */
3425void
3426xfs_log_ticket_put(
3427 xlog_ticket_t *ticket)
3428{
3429 ASSERT(atomic_read(&ticket->t_ref) > 0);
3430 if (atomic_dec_and_test(&ticket->t_ref))
3431 kmem_cache_free(xfs_log_ticket_zone, ticket);
3432}
3433
3434xlog_ticket_t *
3435xfs_log_ticket_get(
3436 xlog_ticket_t *ticket)
3437{
3438 ASSERT(atomic_read(&ticket->t_ref) > 0);
3439 atomic_inc(&ticket->t_ref);
3440 return ticket;
3441}
3442
3443/*
3444 * Figure out the total log space unit (in bytes) that would be
3445 * required for a log ticket.
3446 */
3447static int
3448xlog_calc_unit_res(
3449 struct xlog *log,
3450 int unit_bytes)
3451{
3452 int iclog_space;
3453 uint num_headers;
3454
3455 /*
3456 * Permanent reservations have up to 'cnt'-1 active log operations
3457 * in the log. A unit in this case is the amount of space for one
3458 * of these log operations. Normal reservations have a cnt of 1
3459 * and their unit amount is the total amount of space required.
3460 *
3461 * The following lines of code account for non-transaction data
3462 * which occupy space in the on-disk log.
3463 *
3464 * Normal form of a transaction is:
3465 * <oph><trans-hdr><start-oph><reg1-oph><reg1><reg2-oph>...<commit-oph>
3466 * and then there are LR hdrs, split-recs and roundoff at end of syncs.
3467 *
3468 * We need to account for all the leadup data and trailer data
3469 * around the transaction data.
3470 * And then we need to account for the worst case in terms of using
3471 * more space.
3472 * The worst case will happen if:
3473 * - the placement of the transaction happens to be such that the
3474 * roundoff is at its maximum
3475 * - the transaction data is synced before the commit record is synced
3476 * i.e. <transaction-data><roundoff> | <commit-rec><roundoff>
3477 * Therefore the commit record is in its own Log Record.
3478 * This can happen as the commit record is called with its
3479 * own region to xlog_write().
3480 * This then means that in the worst case, roundoff can happen for
3481 * the commit-rec as well.
3482 * The commit-rec is smaller than padding in this scenario and so it is
3483 * not added separately.
3484 */
3485
3486 /* for trans header */
3487 unit_bytes += sizeof(xlog_op_header_t);
3488 unit_bytes += sizeof(xfs_trans_header_t);
3489
3490 /* for start-rec */
3491 unit_bytes += sizeof(xlog_op_header_t);
3492
3493 /*
3494 * for LR headers - the space for data in an iclog is the size minus
3495 * the space used for the headers. If we use the iclog size, then we
3496 * undercalculate the number of headers required.
3497 *
3498 * Furthermore - the addition of op headers for split-recs might
3499 * increase the space required enough to require more log and op
3500 * headers, so take that into account too.
3501 *
3502 * IMPORTANT: This reservation makes the assumption that if this
3503 * transaction is the first in an iclog and hence has the LR headers
3504 * accounted to it, then the remaining space in the iclog is
3505 * exclusively for this transaction. i.e. if the transaction is larger
3506 * than the iclog, it will be the only thing in that iclog.
3507 * Fundamentally, this means we must pass the entire log vector to
3508 * xlog_write to guarantee this.
3509 */
3510 iclog_space = log->l_iclog_size - log->l_iclog_hsize;
3511 num_headers = howmany(unit_bytes, iclog_space);
3512
3513 /* for split-recs - ophdrs added when data split over LRs */
3514 unit_bytes += sizeof(xlog_op_header_t) * num_headers;
3515
3516 /* add extra header reservations if we overrun */
3517 while (!num_headers ||
3518 howmany(unit_bytes, iclog_space) > num_headers) {
3519 unit_bytes += sizeof(xlog_op_header_t);
3520 num_headers++;
3521 }
3522 unit_bytes += log->l_iclog_hsize * num_headers;
3523
3524 /* for commit-rec LR header - note: padding will subsume the ophdr */
3525 unit_bytes += log->l_iclog_hsize;
3526
3527 /* roundoff padding for transaction data and one for commit record */
3528 unit_bytes += 2 * log->l_iclog_roundoff;
3529
3530 return unit_bytes;
3531}
3532
3533int
3534xfs_log_calc_unit_res(
3535 struct xfs_mount *mp,
3536 int unit_bytes)
3537{
3538 return xlog_calc_unit_res(mp->m_log, unit_bytes);
3539}
3540
3541/*
3542 * Allocate and initialise a new log ticket.
3543 */
3544struct xlog_ticket *
3545xlog_ticket_alloc(
3546 struct xlog *log,
3547 int unit_bytes,
3548 int cnt,
3549 char client,
3550 bool permanent)
3551{
3552 struct xlog_ticket *tic;
3553 int unit_res;
3554
3555 tic = kmem_cache_zalloc(xfs_log_ticket_zone, GFP_NOFS | __GFP_NOFAIL);
3556
3557 unit_res = xlog_calc_unit_res(log, unit_bytes);
3558
3559 atomic_set(&tic->t_ref, 1);
3560 tic->t_task = current;
3561 INIT_LIST_HEAD(&tic->t_queue);
3562 tic->t_unit_res = unit_res;
3563 tic->t_curr_res = unit_res;
3564 tic->t_cnt = cnt;
3565 tic->t_ocnt = cnt;
3566 tic->t_tid = prandom_u32();
3567 tic->t_clientid = client;
3568 if (permanent)
3569 tic->t_flags |= XLOG_TIC_PERM_RESERV;
3570
3571 xlog_tic_reset_res(tic);
3572
3573 return tic;
3574}
3575
3576#if defined(DEBUG)
3577/*
3578 * Make sure that the destination ptr is within the valid data region of
3579 * one of the iclogs. This uses backup pointers stored in a different
3580 * part of the log in case we trash the log structure.
3581 */
3582STATIC void
3583xlog_verify_dest_ptr(
3584 struct xlog *log,
3585 void *ptr)
3586{
3587 int i;
3588 int good_ptr = 0;
3589
3590 for (i = 0; i < log->l_iclog_bufs; i++) {
3591 if (ptr >= log->l_iclog_bak[i] &&
3592 ptr <= log->l_iclog_bak[i] + log->l_iclog_size)
3593 good_ptr++;
3594 }
3595
3596 if (!good_ptr)
3597 xfs_emerg(log->l_mp, "%s: invalid ptr", __func__);
3598}
3599
3600/*
3601 * Check to make sure the grant write head didn't just over lap the tail. If
3602 * the cycles are the same, we can't be overlapping. Otherwise, make sure that
3603 * the cycles differ by exactly one and check the byte count.
3604 *
3605 * This check is run unlocked, so can give false positives. Rather than assert
3606 * on failures, use a warn-once flag and a panic tag to allow the admin to
3607 * determine if they want to panic the machine when such an error occurs. For
3608 * debug kernels this will have the same effect as using an assert but, unlinke
3609 * an assert, it can be turned off at runtime.
3610 */
3611STATIC void
3612xlog_verify_grant_tail(
3613 struct xlog *log)
3614{
3615 int tail_cycle, tail_blocks;
3616 int cycle, space;
3617
3618 xlog_crack_grant_head(&log->l_write_head.grant, &cycle, &space);
3619 xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_blocks);
3620 if (tail_cycle != cycle) {
3621 if (cycle - 1 != tail_cycle &&
3622 !(log->l_flags & XLOG_TAIL_WARN)) {
3623 xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
3624 "%s: cycle - 1 != tail_cycle", __func__);
3625 log->l_flags |= XLOG_TAIL_WARN;
3626 }
3627
3628 if (space > BBTOB(tail_blocks) &&
3629 !(log->l_flags & XLOG_TAIL_WARN)) {
3630 xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
3631 "%s: space > BBTOB(tail_blocks)", __func__);
3632 log->l_flags |= XLOG_TAIL_WARN;
3633 }
3634 }
3635}
3636
3637/* check if it will fit */
3638STATIC void
3639xlog_verify_tail_lsn(
3640 struct xlog *log,
3641 struct xlog_in_core *iclog)
3642{
3643 xfs_lsn_t tail_lsn = be64_to_cpu(iclog->ic_header.h_tail_lsn);
3644 int blocks;
3645
3646 if (CYCLE_LSN(tail_lsn) == log->l_prev_cycle) {
3647 blocks =
3648 log->l_logBBsize - (log->l_prev_block - BLOCK_LSN(tail_lsn));
3649 if (blocks < BTOBB(iclog->ic_offset)+BTOBB(log->l_iclog_hsize))
3650 xfs_emerg(log->l_mp, "%s: ran out of log space", __func__);
3651 } else {
3652 ASSERT(CYCLE_LSN(tail_lsn)+1 == log->l_prev_cycle);
3653
3654 if (BLOCK_LSN(tail_lsn) == log->l_prev_block)
3655 xfs_emerg(log->l_mp, "%s: tail wrapped", __func__);
3656
3657 blocks = BLOCK_LSN(tail_lsn) - log->l_prev_block;
3658 if (blocks < BTOBB(iclog->ic_offset) + 1)
3659 xfs_emerg(log->l_mp, "%s: ran out of log space", __func__);
3660 }
3661}
3662
3663/*
3664 * Perform a number of checks on the iclog before writing to disk.
3665 *
3666 * 1. Make sure the iclogs are still circular
3667 * 2. Make sure we have a good magic number
3668 * 3. Make sure we don't have magic numbers in the data
3669 * 4. Check fields of each log operation header for:
3670 * A. Valid client identifier
3671 * B. tid ptr value falls in valid ptr space (user space code)
3672 * C. Length in log record header is correct according to the
3673 * individual operation headers within record.
3674 * 5. When a bwrite will occur within 5 blocks of the front of the physical
3675 * log, check the preceding blocks of the physical log to make sure all
3676 * the cycle numbers agree with the current cycle number.
3677 */
3678STATIC void
3679xlog_verify_iclog(
3680 struct xlog *log,
3681 struct xlog_in_core *iclog,
3682 int count)
3683{
3684 xlog_op_header_t *ophead;
3685 xlog_in_core_t *icptr;
3686 xlog_in_core_2_t *xhdr;
3687 void *base_ptr, *ptr, *p;
3688 ptrdiff_t field_offset;
3689 uint8_t clientid;
3690 int len, i, j, k, op_len;
3691 int idx;
3692
3693 /* check validity of iclog pointers */
3694 spin_lock(&log->l_icloglock);
3695 icptr = log->l_iclog;
3696 for (i = 0; i < log->l_iclog_bufs; i++, icptr = icptr->ic_next)
3697 ASSERT(icptr);
3698
3699 if (icptr != log->l_iclog)
3700 xfs_emerg(log->l_mp, "%s: corrupt iclog ring", __func__);
3701 spin_unlock(&log->l_icloglock);
3702
3703 /* check log magic numbers */
3704 if (iclog->ic_header.h_magicno != cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
3705 xfs_emerg(log->l_mp, "%s: invalid magic num", __func__);
3706
3707 base_ptr = ptr = &iclog->ic_header;
3708 p = &iclog->ic_header;
3709 for (ptr += BBSIZE; ptr < base_ptr + count; ptr += BBSIZE) {
3710 if (*(__be32 *)ptr == cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
3711 xfs_emerg(log->l_mp, "%s: unexpected magic num",
3712 __func__);
3713 }
3714
3715 /* check fields */
3716 len = be32_to_cpu(iclog->ic_header.h_num_logops);
3717 base_ptr = ptr = iclog->ic_datap;
3718 ophead = ptr;
3719 xhdr = iclog->ic_data;
3720 for (i = 0; i < len; i++) {
3721 ophead = ptr;
3722
3723 /* clientid is only 1 byte */
3724 p = &ophead->oh_clientid;
3725 field_offset = p - base_ptr;
3726 if (field_offset & 0x1ff) {
3727 clientid = ophead->oh_clientid;
3728 } else {
3729 idx = BTOBBT((char *)&ophead->oh_clientid - iclog->ic_datap);
3730 if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
3731 j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3732 k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3733 clientid = xlog_get_client_id(
3734 xhdr[j].hic_xheader.xh_cycle_data[k]);
3735 } else {
3736 clientid = xlog_get_client_id(
3737 iclog->ic_header.h_cycle_data[idx]);
3738 }
3739 }
3740 if (clientid != XFS_TRANSACTION && clientid != XFS_LOG)
3741 xfs_warn(log->l_mp,
3742 "%s: invalid clientid %d op "PTR_FMT" offset 0x%lx",
3743 __func__, clientid, ophead,
3744 (unsigned long)field_offset);
3745
3746 /* check length */
3747 p = &ophead->oh_len;
3748 field_offset = p - base_ptr;
3749 if (field_offset & 0x1ff) {
3750 op_len = be32_to_cpu(ophead->oh_len);
3751 } else {
3752 idx = BTOBBT((uintptr_t)&ophead->oh_len -
3753 (uintptr_t)iclog->ic_datap);
3754 if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
3755 j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3756 k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3757 op_len = be32_to_cpu(xhdr[j].hic_xheader.xh_cycle_data[k]);
3758 } else {
3759 op_len = be32_to_cpu(iclog->ic_header.h_cycle_data[idx]);
3760 }
3761 }
3762 ptr += sizeof(xlog_op_header_t) + op_len;
3763 }
3764}
3765#endif
3766
3767/*
3768 * Mark all iclogs IOERROR. l_icloglock is held by the caller.
3769 */
3770STATIC int
3771xlog_state_ioerror(
3772 struct xlog *log)
3773{
3774 xlog_in_core_t *iclog, *ic;
3775
3776 iclog = log->l_iclog;
3777 if (iclog->ic_state != XLOG_STATE_IOERROR) {
3778 /*
3779 * Mark all the incore logs IOERROR.
3780 * From now on, no log flushes will result.
3781 */
3782 ic = iclog;
3783 do {
3784 ic->ic_state = XLOG_STATE_IOERROR;
3785 ic = ic->ic_next;
3786 } while (ic != iclog);
3787 return 0;
3788 }
3789 /*
3790 * Return non-zero, if state transition has already happened.
3791 */
3792 return 1;
3793}
3794
3795/*
3796 * This is called from xfs_force_shutdown, when we're forcibly
3797 * shutting down the filesystem, typically because of an IO error.
3798 * Our main objectives here are to make sure that:
3799 * a. if !logerror, flush the logs to disk. Anything modified
3800 * after this is ignored.
3801 * b. the filesystem gets marked 'SHUTDOWN' for all interested
3802 * parties to find out, 'atomically'.
3803 * c. those who're sleeping on log reservations, pinned objects and
3804 * other resources get woken up, and be told the bad news.
3805 * d. nothing new gets queued up after (b) and (c) are done.
3806 *
3807 * Note: for the !logerror case we need to flush the regions held in memory out
3808 * to disk first. This needs to be done before the log is marked as shutdown,
3809 * otherwise the iclog writes will fail.
3810 */
3811int
3812xfs_log_force_umount(
3813 struct xfs_mount *mp,
3814 int logerror)
3815{
3816 struct xlog *log;
3817 int retval;
3818
3819 log = mp->m_log;
3820
3821 /*
3822 * If this happens during log recovery, don't worry about
3823 * locking; the log isn't open for business yet.
3824 */
3825 if (!log ||
3826 log->l_flags & XLOG_ACTIVE_RECOVERY) {
3827 mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
3828 if (mp->m_sb_bp)
3829 mp->m_sb_bp->b_flags |= XBF_DONE;
3830 return 0;
3831 }
3832
3833 /*
3834 * Somebody could've already done the hard work for us.
3835 * No need to get locks for this.
3836 */
3837 if (logerror && log->l_iclog->ic_state == XLOG_STATE_IOERROR) {
3838 ASSERT(XLOG_FORCED_SHUTDOWN(log));
3839 return 1;
3840 }
3841
3842 /*
3843 * Flush all the completed transactions to disk before marking the log
3844 * being shut down. We need to do it in this order to ensure that
3845 * completed operations are safely on disk before we shut down, and that
3846 * we don't have to issue any buffer IO after the shutdown flags are set
3847 * to guarantee this.
3848 */
3849 if (!logerror)
3850 xfs_log_force(mp, XFS_LOG_SYNC);
3851
3852 /*
3853 * mark the filesystem and the as in a shutdown state and wake
3854 * everybody up to tell them the bad news.
3855 */
3856 spin_lock(&log->l_icloglock);
3857 mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
3858 if (mp->m_sb_bp)
3859 mp->m_sb_bp->b_flags |= XBF_DONE;
3860
3861 /*
3862 * Mark the log and the iclogs with IO error flags to prevent any
3863 * further log IO from being issued or completed.
3864 */
3865 log->l_flags |= XLOG_IO_ERROR;
3866 retval = xlog_state_ioerror(log);
3867 spin_unlock(&log->l_icloglock);
3868
3869 /*
3870 * We don't want anybody waiting for log reservations after this. That
3871 * means we have to wake up everybody queued up on reserveq as well as
3872 * writeq. In addition, we make sure in xlog_{re}grant_log_space that
3873 * we don't enqueue anything once the SHUTDOWN flag is set, and this
3874 * action is protected by the grant locks.
3875 */
3876 xlog_grant_head_wake_all(&log->l_reserve_head);
3877 xlog_grant_head_wake_all(&log->l_write_head);
3878
3879 /*
3880 * Wake up everybody waiting on xfs_log_force. Wake the CIL push first
3881 * as if the log writes were completed. The abort handling in the log
3882 * item committed callback functions will do this again under lock to
3883 * avoid races.
3884 */
3885 spin_lock(&log->l_cilp->xc_push_lock);
3886 wake_up_all(&log->l_cilp->xc_commit_wait);
3887 spin_unlock(&log->l_cilp->xc_push_lock);
3888 xlog_state_do_callback(log);
3889
3890 /* return non-zero if log IOERROR transition had already happened */
3891 return retval;
3892}
3893
3894STATIC int
3895xlog_iclogs_empty(
3896 struct xlog *log)
3897{
3898 xlog_in_core_t *iclog;
3899
3900 iclog = log->l_iclog;
3901 do {
3902 /* endianness does not matter here, zero is zero in
3903 * any language.
3904 */
3905 if (iclog->ic_header.h_num_logops)
3906 return 0;
3907 iclog = iclog->ic_next;
3908 } while (iclog != log->l_iclog);
3909 return 1;
3910}
3911
3912/*
3913 * Verify that an LSN stamped into a piece of metadata is valid. This is
3914 * intended for use in read verifiers on v5 superblocks.
3915 */
3916bool
3917xfs_log_check_lsn(
3918 struct xfs_mount *mp,
3919 xfs_lsn_t lsn)
3920{
3921 struct xlog *log = mp->m_log;
3922 bool valid;
3923
3924 /*
3925 * norecovery mode skips mount-time log processing and unconditionally
3926 * resets the in-core LSN. We can't validate in this mode, but
3927 * modifications are not allowed anyways so just return true.
3928 */
3929 if (mp->m_flags & XFS_MOUNT_NORECOVERY)
3930 return true;
3931
3932 /*
3933 * Some metadata LSNs are initialized to NULL (e.g., the agfl). This is
3934 * handled by recovery and thus safe to ignore here.
3935 */
3936 if (lsn == NULLCOMMITLSN)
3937 return true;
3938
3939 valid = xlog_valid_lsn(mp->m_log, lsn);
3940
3941 /* warn the user about what's gone wrong before verifier failure */
3942 if (!valid) {
3943 spin_lock(&log->l_icloglock);
3944 xfs_warn(mp,
3945"Corruption warning: Metadata has LSN (%d:%d) ahead of current LSN (%d:%d). "
3946"Please unmount and run xfs_repair (>= v4.3) to resolve.",
3947 CYCLE_LSN(lsn), BLOCK_LSN(lsn),
3948 log->l_curr_cycle, log->l_curr_block);
3949 spin_unlock(&log->l_icloglock);
3950 }
3951
3952 return valid;
3953}
3954
3955bool
3956xfs_log_in_recovery(
3957 struct xfs_mount *mp)
3958{
3959 struct xlog *log = mp->m_log;
3960
3961 return log->l_flags & XLOG_ACTIVE_RECOVERY;
3962}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2000-2005 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_mount.h"
13#include "xfs_errortag.h"
14#include "xfs_error.h"
15#include "xfs_trans.h"
16#include "xfs_trans_priv.h"
17#include "xfs_log.h"
18#include "xfs_log_priv.h"
19#include "xfs_trace.h"
20#include "xfs_sysfs.h"
21#include "xfs_sb.h"
22#include "xfs_health.h"
23
24struct kmem_cache *xfs_log_ticket_cache;
25
26/* Local miscellaneous function prototypes */
27STATIC struct xlog *
28xlog_alloc_log(
29 struct xfs_mount *mp,
30 struct xfs_buftarg *log_target,
31 xfs_daddr_t blk_offset,
32 int num_bblks);
33STATIC int
34xlog_space_left(
35 struct xlog *log,
36 atomic64_t *head);
37STATIC void
38xlog_dealloc_log(
39 struct xlog *log);
40
41/* local state machine functions */
42STATIC void xlog_state_done_syncing(
43 struct xlog_in_core *iclog);
44STATIC void xlog_state_do_callback(
45 struct xlog *log);
46STATIC int
47xlog_state_get_iclog_space(
48 struct xlog *log,
49 int len,
50 struct xlog_in_core **iclog,
51 struct xlog_ticket *ticket,
52 int *logoffsetp);
53STATIC void
54xlog_grant_push_ail(
55 struct xlog *log,
56 int need_bytes);
57STATIC void
58xlog_sync(
59 struct xlog *log,
60 struct xlog_in_core *iclog,
61 struct xlog_ticket *ticket);
62#if defined(DEBUG)
63STATIC void
64xlog_verify_grant_tail(
65 struct xlog *log);
66STATIC void
67xlog_verify_iclog(
68 struct xlog *log,
69 struct xlog_in_core *iclog,
70 int count);
71STATIC void
72xlog_verify_tail_lsn(
73 struct xlog *log,
74 struct xlog_in_core *iclog);
75#else
76#define xlog_verify_grant_tail(a)
77#define xlog_verify_iclog(a,b,c)
78#define xlog_verify_tail_lsn(a,b)
79#endif
80
81STATIC int
82xlog_iclogs_empty(
83 struct xlog *log);
84
85static int
86xfs_log_cover(struct xfs_mount *);
87
88/*
89 * We need to make sure the buffer pointer returned is naturally aligned for the
90 * biggest basic data type we put into it. We have already accounted for this
91 * padding when sizing the buffer.
92 *
93 * However, this padding does not get written into the log, and hence we have to
94 * track the space used by the log vectors separately to prevent log space hangs
95 * due to inaccurate accounting (i.e. a leak) of the used log space through the
96 * CIL context ticket.
97 *
98 * We also add space for the xlog_op_header that describes this region in the
99 * log. This prepends the data region we return to the caller to copy their data
100 * into, so do all the static initialisation of the ophdr now. Because the ophdr
101 * is not 8 byte aligned, we have to be careful to ensure that we align the
102 * start of the buffer such that the region we return to the call is 8 byte
103 * aligned and packed against the tail of the ophdr.
104 */
105void *
106xlog_prepare_iovec(
107 struct xfs_log_vec *lv,
108 struct xfs_log_iovec **vecp,
109 uint type)
110{
111 struct xfs_log_iovec *vec = *vecp;
112 struct xlog_op_header *oph;
113 uint32_t len;
114 void *buf;
115
116 if (vec) {
117 ASSERT(vec - lv->lv_iovecp < lv->lv_niovecs);
118 vec++;
119 } else {
120 vec = &lv->lv_iovecp[0];
121 }
122
123 len = lv->lv_buf_len + sizeof(struct xlog_op_header);
124 if (!IS_ALIGNED(len, sizeof(uint64_t))) {
125 lv->lv_buf_len = round_up(len, sizeof(uint64_t)) -
126 sizeof(struct xlog_op_header);
127 }
128
129 vec->i_type = type;
130 vec->i_addr = lv->lv_buf + lv->lv_buf_len;
131
132 oph = vec->i_addr;
133 oph->oh_clientid = XFS_TRANSACTION;
134 oph->oh_res2 = 0;
135 oph->oh_flags = 0;
136
137 buf = vec->i_addr + sizeof(struct xlog_op_header);
138 ASSERT(IS_ALIGNED((unsigned long)buf, sizeof(uint64_t)));
139
140 *vecp = vec;
141 return buf;
142}
143
144static void
145xlog_grant_sub_space(
146 struct xlog *log,
147 atomic64_t *head,
148 int bytes)
149{
150 int64_t head_val = atomic64_read(head);
151 int64_t new, old;
152
153 do {
154 int cycle, space;
155
156 xlog_crack_grant_head_val(head_val, &cycle, &space);
157
158 space -= bytes;
159 if (space < 0) {
160 space += log->l_logsize;
161 cycle--;
162 }
163
164 old = head_val;
165 new = xlog_assign_grant_head_val(cycle, space);
166 head_val = atomic64_cmpxchg(head, old, new);
167 } while (head_val != old);
168}
169
170static void
171xlog_grant_add_space(
172 struct xlog *log,
173 atomic64_t *head,
174 int bytes)
175{
176 int64_t head_val = atomic64_read(head);
177 int64_t new, old;
178
179 do {
180 int tmp;
181 int cycle, space;
182
183 xlog_crack_grant_head_val(head_val, &cycle, &space);
184
185 tmp = log->l_logsize - space;
186 if (tmp > bytes)
187 space += bytes;
188 else {
189 space = bytes - tmp;
190 cycle++;
191 }
192
193 old = head_val;
194 new = xlog_assign_grant_head_val(cycle, space);
195 head_val = atomic64_cmpxchg(head, old, new);
196 } while (head_val != old);
197}
198
199STATIC void
200xlog_grant_head_init(
201 struct xlog_grant_head *head)
202{
203 xlog_assign_grant_head(&head->grant, 1, 0);
204 INIT_LIST_HEAD(&head->waiters);
205 spin_lock_init(&head->lock);
206}
207
208STATIC void
209xlog_grant_head_wake_all(
210 struct xlog_grant_head *head)
211{
212 struct xlog_ticket *tic;
213
214 spin_lock(&head->lock);
215 list_for_each_entry(tic, &head->waiters, t_queue)
216 wake_up_process(tic->t_task);
217 spin_unlock(&head->lock);
218}
219
220static inline int
221xlog_ticket_reservation(
222 struct xlog *log,
223 struct xlog_grant_head *head,
224 struct xlog_ticket *tic)
225{
226 if (head == &log->l_write_head) {
227 ASSERT(tic->t_flags & XLOG_TIC_PERM_RESERV);
228 return tic->t_unit_res;
229 }
230
231 if (tic->t_flags & XLOG_TIC_PERM_RESERV)
232 return tic->t_unit_res * tic->t_cnt;
233
234 return tic->t_unit_res;
235}
236
237STATIC bool
238xlog_grant_head_wake(
239 struct xlog *log,
240 struct xlog_grant_head *head,
241 int *free_bytes)
242{
243 struct xlog_ticket *tic;
244 int need_bytes;
245 bool woken_task = false;
246
247 list_for_each_entry(tic, &head->waiters, t_queue) {
248
249 /*
250 * There is a chance that the size of the CIL checkpoints in
251 * progress at the last AIL push target calculation resulted in
252 * limiting the target to the log head (l_last_sync_lsn) at the
253 * time. This may not reflect where the log head is now as the
254 * CIL checkpoints may have completed.
255 *
256 * Hence when we are woken here, it may be that the head of the
257 * log that has moved rather than the tail. As the tail didn't
258 * move, there still won't be space available for the
259 * reservation we require. However, if the AIL has already
260 * pushed to the target defined by the old log head location, we
261 * will hang here waiting for something else to update the AIL
262 * push target.
263 *
264 * Therefore, if there isn't space to wake the first waiter on
265 * the grant head, we need to push the AIL again to ensure the
266 * target reflects both the current log tail and log head
267 * position before we wait for the tail to move again.
268 */
269
270 need_bytes = xlog_ticket_reservation(log, head, tic);
271 if (*free_bytes < need_bytes) {
272 if (!woken_task)
273 xlog_grant_push_ail(log, need_bytes);
274 return false;
275 }
276
277 *free_bytes -= need_bytes;
278 trace_xfs_log_grant_wake_up(log, tic);
279 wake_up_process(tic->t_task);
280 woken_task = true;
281 }
282
283 return true;
284}
285
286STATIC int
287xlog_grant_head_wait(
288 struct xlog *log,
289 struct xlog_grant_head *head,
290 struct xlog_ticket *tic,
291 int need_bytes) __releases(&head->lock)
292 __acquires(&head->lock)
293{
294 list_add_tail(&tic->t_queue, &head->waiters);
295
296 do {
297 if (xlog_is_shutdown(log))
298 goto shutdown;
299 xlog_grant_push_ail(log, need_bytes);
300
301 __set_current_state(TASK_UNINTERRUPTIBLE);
302 spin_unlock(&head->lock);
303
304 XFS_STATS_INC(log->l_mp, xs_sleep_logspace);
305
306 trace_xfs_log_grant_sleep(log, tic);
307 schedule();
308 trace_xfs_log_grant_wake(log, tic);
309
310 spin_lock(&head->lock);
311 if (xlog_is_shutdown(log))
312 goto shutdown;
313 } while (xlog_space_left(log, &head->grant) < need_bytes);
314
315 list_del_init(&tic->t_queue);
316 return 0;
317shutdown:
318 list_del_init(&tic->t_queue);
319 return -EIO;
320}
321
322/*
323 * Atomically get the log space required for a log ticket.
324 *
325 * Once a ticket gets put onto head->waiters, it will only return after the
326 * needed reservation is satisfied.
327 *
328 * This function is structured so that it has a lock free fast path. This is
329 * necessary because every new transaction reservation will come through this
330 * path. Hence any lock will be globally hot if we take it unconditionally on
331 * every pass.
332 *
333 * As tickets are only ever moved on and off head->waiters under head->lock, we
334 * only need to take that lock if we are going to add the ticket to the queue
335 * and sleep. We can avoid taking the lock if the ticket was never added to
336 * head->waiters because the t_queue list head will be empty and we hold the
337 * only reference to it so it can safely be checked unlocked.
338 */
339STATIC int
340xlog_grant_head_check(
341 struct xlog *log,
342 struct xlog_grant_head *head,
343 struct xlog_ticket *tic,
344 int *need_bytes)
345{
346 int free_bytes;
347 int error = 0;
348
349 ASSERT(!xlog_in_recovery(log));
350
351 /*
352 * If there are other waiters on the queue then give them a chance at
353 * logspace before us. Wake up the first waiters, if we do not wake
354 * up all the waiters then go to sleep waiting for more free space,
355 * otherwise try to get some space for this transaction.
356 */
357 *need_bytes = xlog_ticket_reservation(log, head, tic);
358 free_bytes = xlog_space_left(log, &head->grant);
359 if (!list_empty_careful(&head->waiters)) {
360 spin_lock(&head->lock);
361 if (!xlog_grant_head_wake(log, head, &free_bytes) ||
362 free_bytes < *need_bytes) {
363 error = xlog_grant_head_wait(log, head, tic,
364 *need_bytes);
365 }
366 spin_unlock(&head->lock);
367 } else if (free_bytes < *need_bytes) {
368 spin_lock(&head->lock);
369 error = xlog_grant_head_wait(log, head, tic, *need_bytes);
370 spin_unlock(&head->lock);
371 }
372
373 return error;
374}
375
376bool
377xfs_log_writable(
378 struct xfs_mount *mp)
379{
380 /*
381 * Do not write to the log on norecovery mounts, if the data or log
382 * devices are read-only, or if the filesystem is shutdown. Read-only
383 * mounts allow internal writes for log recovery and unmount purposes,
384 * so don't restrict that case.
385 */
386 if (xfs_has_norecovery(mp))
387 return false;
388 if (xfs_readonly_buftarg(mp->m_ddev_targp))
389 return false;
390 if (xfs_readonly_buftarg(mp->m_log->l_targ))
391 return false;
392 if (xlog_is_shutdown(mp->m_log))
393 return false;
394 return true;
395}
396
397/*
398 * Replenish the byte reservation required by moving the grant write head.
399 */
400int
401xfs_log_regrant(
402 struct xfs_mount *mp,
403 struct xlog_ticket *tic)
404{
405 struct xlog *log = mp->m_log;
406 int need_bytes;
407 int error = 0;
408
409 if (xlog_is_shutdown(log))
410 return -EIO;
411
412 XFS_STATS_INC(mp, xs_try_logspace);
413
414 /*
415 * This is a new transaction on the ticket, so we need to change the
416 * transaction ID so that the next transaction has a different TID in
417 * the log. Just add one to the existing tid so that we can see chains
418 * of rolling transactions in the log easily.
419 */
420 tic->t_tid++;
421
422 xlog_grant_push_ail(log, tic->t_unit_res);
423
424 tic->t_curr_res = tic->t_unit_res;
425 if (tic->t_cnt > 0)
426 return 0;
427
428 trace_xfs_log_regrant(log, tic);
429
430 error = xlog_grant_head_check(log, &log->l_write_head, tic,
431 &need_bytes);
432 if (error)
433 goto out_error;
434
435 xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
436 trace_xfs_log_regrant_exit(log, tic);
437 xlog_verify_grant_tail(log);
438 return 0;
439
440out_error:
441 /*
442 * If we are failing, make sure the ticket doesn't have any current
443 * reservations. We don't want to add this back when the ticket/
444 * transaction gets cancelled.
445 */
446 tic->t_curr_res = 0;
447 tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
448 return error;
449}
450
451/*
452 * Reserve log space and return a ticket corresponding to the reservation.
453 *
454 * Each reservation is going to reserve extra space for a log record header.
455 * When writes happen to the on-disk log, we don't subtract the length of the
456 * log record header from any reservation. By wasting space in each
457 * reservation, we prevent over allocation problems.
458 */
459int
460xfs_log_reserve(
461 struct xfs_mount *mp,
462 int unit_bytes,
463 int cnt,
464 struct xlog_ticket **ticp,
465 bool permanent)
466{
467 struct xlog *log = mp->m_log;
468 struct xlog_ticket *tic;
469 int need_bytes;
470 int error = 0;
471
472 if (xlog_is_shutdown(log))
473 return -EIO;
474
475 XFS_STATS_INC(mp, xs_try_logspace);
476
477 ASSERT(*ticp == NULL);
478 tic = xlog_ticket_alloc(log, unit_bytes, cnt, permanent);
479 *ticp = tic;
480
481 xlog_grant_push_ail(log, tic->t_cnt ? tic->t_unit_res * tic->t_cnt
482 : tic->t_unit_res);
483
484 trace_xfs_log_reserve(log, tic);
485
486 error = xlog_grant_head_check(log, &log->l_reserve_head, tic,
487 &need_bytes);
488 if (error)
489 goto out_error;
490
491 xlog_grant_add_space(log, &log->l_reserve_head.grant, need_bytes);
492 xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
493 trace_xfs_log_reserve_exit(log, tic);
494 xlog_verify_grant_tail(log);
495 return 0;
496
497out_error:
498 /*
499 * If we are failing, make sure the ticket doesn't have any current
500 * reservations. We don't want to add this back when the ticket/
501 * transaction gets cancelled.
502 */
503 tic->t_curr_res = 0;
504 tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
505 return error;
506}
507
508/*
509 * Run all the pending iclog callbacks and wake log force waiters and iclog
510 * space waiters so they can process the newly set shutdown state. We really
511 * don't care what order we process callbacks here because the log is shut down
512 * and so state cannot change on disk anymore. However, we cannot wake waiters
513 * until the callbacks have been processed because we may be in unmount and
514 * we must ensure that all AIL operations the callbacks perform have completed
515 * before we tear down the AIL.
516 *
517 * We avoid processing actively referenced iclogs so that we don't run callbacks
518 * while the iclog owner might still be preparing the iclog for IO submssion.
519 * These will be caught by xlog_state_iclog_release() and call this function
520 * again to process any callbacks that may have been added to that iclog.
521 */
522static void
523xlog_state_shutdown_callbacks(
524 struct xlog *log)
525{
526 struct xlog_in_core *iclog;
527 LIST_HEAD(cb_list);
528
529 iclog = log->l_iclog;
530 do {
531 if (atomic_read(&iclog->ic_refcnt)) {
532 /* Reference holder will re-run iclog callbacks. */
533 continue;
534 }
535 list_splice_init(&iclog->ic_callbacks, &cb_list);
536 spin_unlock(&log->l_icloglock);
537
538 xlog_cil_process_committed(&cb_list);
539
540 spin_lock(&log->l_icloglock);
541 wake_up_all(&iclog->ic_write_wait);
542 wake_up_all(&iclog->ic_force_wait);
543 } while ((iclog = iclog->ic_next) != log->l_iclog);
544
545 wake_up_all(&log->l_flush_wait);
546}
547
548/*
549 * Flush iclog to disk if this is the last reference to the given iclog and the
550 * it is in the WANT_SYNC state.
551 *
552 * If XLOG_ICL_NEED_FUA is already set on the iclog, we need to ensure that the
553 * log tail is updated correctly. NEED_FUA indicates that the iclog will be
554 * written to stable storage, and implies that a commit record is contained
555 * within the iclog. We need to ensure that the log tail does not move beyond
556 * the tail that the first commit record in the iclog ordered against, otherwise
557 * correct recovery of that checkpoint becomes dependent on future operations
558 * performed on this iclog.
559 *
560 * Hence if NEED_FUA is set and the current iclog tail lsn is empty, write the
561 * current tail into iclog. Once the iclog tail is set, future operations must
562 * not modify it, otherwise they potentially violate ordering constraints for
563 * the checkpoint commit that wrote the initial tail lsn value. The tail lsn in
564 * the iclog will get zeroed on activation of the iclog after sync, so we
565 * always capture the tail lsn on the iclog on the first NEED_FUA release
566 * regardless of the number of active reference counts on this iclog.
567 */
568int
569xlog_state_release_iclog(
570 struct xlog *log,
571 struct xlog_in_core *iclog,
572 struct xlog_ticket *ticket)
573{
574 xfs_lsn_t tail_lsn;
575 bool last_ref;
576
577 lockdep_assert_held(&log->l_icloglock);
578
579 trace_xlog_iclog_release(iclog, _RET_IP_);
580 /*
581 * Grabbing the current log tail needs to be atomic w.r.t. the writing
582 * of the tail LSN into the iclog so we guarantee that the log tail does
583 * not move between the first time we know that the iclog needs to be
584 * made stable and when we eventually submit it.
585 */
586 if ((iclog->ic_state == XLOG_STATE_WANT_SYNC ||
587 (iclog->ic_flags & XLOG_ICL_NEED_FUA)) &&
588 !iclog->ic_header.h_tail_lsn) {
589 tail_lsn = xlog_assign_tail_lsn(log->l_mp);
590 iclog->ic_header.h_tail_lsn = cpu_to_be64(tail_lsn);
591 }
592
593 last_ref = atomic_dec_and_test(&iclog->ic_refcnt);
594
595 if (xlog_is_shutdown(log)) {
596 /*
597 * If there are no more references to this iclog, process the
598 * pending iclog callbacks that were waiting on the release of
599 * this iclog.
600 */
601 if (last_ref)
602 xlog_state_shutdown_callbacks(log);
603 return -EIO;
604 }
605
606 if (!last_ref)
607 return 0;
608
609 if (iclog->ic_state != XLOG_STATE_WANT_SYNC) {
610 ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE);
611 return 0;
612 }
613
614 iclog->ic_state = XLOG_STATE_SYNCING;
615 xlog_verify_tail_lsn(log, iclog);
616 trace_xlog_iclog_syncing(iclog, _RET_IP_);
617
618 spin_unlock(&log->l_icloglock);
619 xlog_sync(log, iclog, ticket);
620 spin_lock(&log->l_icloglock);
621 return 0;
622}
623
624/*
625 * Mount a log filesystem
626 *
627 * mp - ubiquitous xfs mount point structure
628 * log_target - buftarg of on-disk log device
629 * blk_offset - Start block # where block size is 512 bytes (BBSIZE)
630 * num_bblocks - Number of BBSIZE blocks in on-disk log
631 *
632 * Return error or zero.
633 */
634int
635xfs_log_mount(
636 xfs_mount_t *mp,
637 xfs_buftarg_t *log_target,
638 xfs_daddr_t blk_offset,
639 int num_bblks)
640{
641 struct xlog *log;
642 int error = 0;
643 int min_logfsbs;
644
645 if (!xfs_has_norecovery(mp)) {
646 xfs_notice(mp, "Mounting V%d Filesystem %pU",
647 XFS_SB_VERSION_NUM(&mp->m_sb),
648 &mp->m_sb.sb_uuid);
649 } else {
650 xfs_notice(mp,
651"Mounting V%d filesystem %pU in no-recovery mode. Filesystem will be inconsistent.",
652 XFS_SB_VERSION_NUM(&mp->m_sb),
653 &mp->m_sb.sb_uuid);
654 ASSERT(xfs_is_readonly(mp));
655 }
656
657 log = xlog_alloc_log(mp, log_target, blk_offset, num_bblks);
658 if (IS_ERR(log)) {
659 error = PTR_ERR(log);
660 goto out;
661 }
662 mp->m_log = log;
663
664 /*
665 * Now that we have set up the log and it's internal geometry
666 * parameters, we can validate the given log space and drop a critical
667 * message via syslog if the log size is too small. A log that is too
668 * small can lead to unexpected situations in transaction log space
669 * reservation stage. The superblock verifier has already validated all
670 * the other log geometry constraints, so we don't have to check those
671 * here.
672 *
673 * Note: For v4 filesystems, we can't just reject the mount if the
674 * validation fails. This would mean that people would have to
675 * downgrade their kernel just to remedy the situation as there is no
676 * way to grow the log (short of black magic surgery with xfs_db).
677 *
678 * We can, however, reject mounts for V5 format filesystems, as the
679 * mkfs binary being used to make the filesystem should never create a
680 * filesystem with a log that is too small.
681 */
682 min_logfsbs = xfs_log_calc_minimum_size(mp);
683 if (mp->m_sb.sb_logblocks < min_logfsbs) {
684 xfs_warn(mp,
685 "Log size %d blocks too small, minimum size is %d blocks",
686 mp->m_sb.sb_logblocks, min_logfsbs);
687
688 /*
689 * Log check errors are always fatal on v5; or whenever bad
690 * metadata leads to a crash.
691 */
692 if (xfs_has_crc(mp)) {
693 xfs_crit(mp, "AAIEEE! Log failed size checks. Abort!");
694 ASSERT(0);
695 error = -EINVAL;
696 goto out_free_log;
697 }
698 xfs_crit(mp, "Log size out of supported range.");
699 xfs_crit(mp,
700"Continuing onwards, but if log hangs are experienced then please report this message in the bug report.");
701 }
702
703 /*
704 * Initialize the AIL now we have a log.
705 */
706 error = xfs_trans_ail_init(mp);
707 if (error) {
708 xfs_warn(mp, "AIL initialisation failed: error %d", error);
709 goto out_free_log;
710 }
711 log->l_ailp = mp->m_ail;
712
713 /*
714 * skip log recovery on a norecovery mount. pretend it all
715 * just worked.
716 */
717 if (!xfs_has_norecovery(mp)) {
718 error = xlog_recover(log);
719 if (error) {
720 xfs_warn(mp, "log mount/recovery failed: error %d",
721 error);
722 xlog_recover_cancel(log);
723 goto out_destroy_ail;
724 }
725 }
726
727 error = xfs_sysfs_init(&log->l_kobj, &xfs_log_ktype, &mp->m_kobj,
728 "log");
729 if (error)
730 goto out_destroy_ail;
731
732 /* Normal transactions can now occur */
733 clear_bit(XLOG_ACTIVE_RECOVERY, &log->l_opstate);
734
735 /*
736 * Now the log has been fully initialised and we know were our
737 * space grant counters are, we can initialise the permanent ticket
738 * needed for delayed logging to work.
739 */
740 xlog_cil_init_post_recovery(log);
741
742 return 0;
743
744out_destroy_ail:
745 xfs_trans_ail_destroy(mp);
746out_free_log:
747 xlog_dealloc_log(log);
748out:
749 return error;
750}
751
752/*
753 * Finish the recovery of the file system. This is separate from the
754 * xfs_log_mount() call, because it depends on the code in xfs_mountfs() to read
755 * in the root and real-time bitmap inodes between calling xfs_log_mount() and
756 * here.
757 *
758 * If we finish recovery successfully, start the background log work. If we are
759 * not doing recovery, then we have a RO filesystem and we don't need to start
760 * it.
761 */
762int
763xfs_log_mount_finish(
764 struct xfs_mount *mp)
765{
766 struct xlog *log = mp->m_log;
767 int error = 0;
768
769 if (xfs_has_norecovery(mp)) {
770 ASSERT(xfs_is_readonly(mp));
771 return 0;
772 }
773
774 /*
775 * During the second phase of log recovery, we need iget and
776 * iput to behave like they do for an active filesystem.
777 * xfs_fs_drop_inode needs to be able to prevent the deletion
778 * of inodes before we're done replaying log items on those
779 * inodes. Turn it off immediately after recovery finishes
780 * so that we don't leak the quota inodes if subsequent mount
781 * activities fail.
782 *
783 * We let all inodes involved in redo item processing end up on
784 * the LRU instead of being evicted immediately so that if we do
785 * something to an unlinked inode, the irele won't cause
786 * premature truncation and freeing of the inode, which results
787 * in log recovery failure. We have to evict the unreferenced
788 * lru inodes after clearing SB_ACTIVE because we don't
789 * otherwise clean up the lru if there's a subsequent failure in
790 * xfs_mountfs, which leads to us leaking the inodes if nothing
791 * else (e.g. quotacheck) references the inodes before the
792 * mount failure occurs.
793 */
794 mp->m_super->s_flags |= SB_ACTIVE;
795 xfs_log_work_queue(mp);
796 if (xlog_recovery_needed(log))
797 error = xlog_recover_finish(log);
798 mp->m_super->s_flags &= ~SB_ACTIVE;
799 evict_inodes(mp->m_super);
800
801 /*
802 * Drain the buffer LRU after log recovery. This is required for v4
803 * filesystems to avoid leaving around buffers with NULL verifier ops,
804 * but we do it unconditionally to make sure we're always in a clean
805 * cache state after mount.
806 *
807 * Don't push in the error case because the AIL may have pending intents
808 * that aren't removed until recovery is cancelled.
809 */
810 if (xlog_recovery_needed(log)) {
811 if (!error) {
812 xfs_log_force(mp, XFS_LOG_SYNC);
813 xfs_ail_push_all_sync(mp->m_ail);
814 }
815 xfs_notice(mp, "Ending recovery (logdev: %s)",
816 mp->m_logname ? mp->m_logname : "internal");
817 } else {
818 xfs_info(mp, "Ending clean mount");
819 }
820 xfs_buftarg_drain(mp->m_ddev_targp);
821
822 clear_bit(XLOG_RECOVERY_NEEDED, &log->l_opstate);
823
824 /* Make sure the log is dead if we're returning failure. */
825 ASSERT(!error || xlog_is_shutdown(log));
826
827 return error;
828}
829
830/*
831 * The mount has failed. Cancel the recovery if it hasn't completed and destroy
832 * the log.
833 */
834void
835xfs_log_mount_cancel(
836 struct xfs_mount *mp)
837{
838 xlog_recover_cancel(mp->m_log);
839 xfs_log_unmount(mp);
840}
841
842/*
843 * Flush out the iclog to disk ensuring that device caches are flushed and
844 * the iclog hits stable storage before any completion waiters are woken.
845 */
846static inline int
847xlog_force_iclog(
848 struct xlog_in_core *iclog)
849{
850 atomic_inc(&iclog->ic_refcnt);
851 iclog->ic_flags |= XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA;
852 if (iclog->ic_state == XLOG_STATE_ACTIVE)
853 xlog_state_switch_iclogs(iclog->ic_log, iclog, 0);
854 return xlog_state_release_iclog(iclog->ic_log, iclog, NULL);
855}
856
857/*
858 * Cycle all the iclogbuf locks to make sure all log IO completion
859 * is done before we tear down these buffers.
860 */
861static void
862xlog_wait_iclog_completion(struct xlog *log)
863{
864 int i;
865 struct xlog_in_core *iclog = log->l_iclog;
866
867 for (i = 0; i < log->l_iclog_bufs; i++) {
868 down(&iclog->ic_sema);
869 up(&iclog->ic_sema);
870 iclog = iclog->ic_next;
871 }
872}
873
874/*
875 * Wait for the iclog and all prior iclogs to be written disk as required by the
876 * log force state machine. Waiting on ic_force_wait ensures iclog completions
877 * have been ordered and callbacks run before we are woken here, hence
878 * guaranteeing that all the iclogs up to this one are on stable storage.
879 */
880int
881xlog_wait_on_iclog(
882 struct xlog_in_core *iclog)
883 __releases(iclog->ic_log->l_icloglock)
884{
885 struct xlog *log = iclog->ic_log;
886
887 trace_xlog_iclog_wait_on(iclog, _RET_IP_);
888 if (!xlog_is_shutdown(log) &&
889 iclog->ic_state != XLOG_STATE_ACTIVE &&
890 iclog->ic_state != XLOG_STATE_DIRTY) {
891 XFS_STATS_INC(log->l_mp, xs_log_force_sleep);
892 xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
893 } else {
894 spin_unlock(&log->l_icloglock);
895 }
896
897 if (xlog_is_shutdown(log))
898 return -EIO;
899 return 0;
900}
901
902/*
903 * Write out an unmount record using the ticket provided. We have to account for
904 * the data space used in the unmount ticket as this write is not done from a
905 * transaction context that has already done the accounting for us.
906 */
907static int
908xlog_write_unmount_record(
909 struct xlog *log,
910 struct xlog_ticket *ticket)
911{
912 struct {
913 struct xlog_op_header ophdr;
914 struct xfs_unmount_log_format ulf;
915 } unmount_rec = {
916 .ophdr = {
917 .oh_clientid = XFS_LOG,
918 .oh_tid = cpu_to_be32(ticket->t_tid),
919 .oh_flags = XLOG_UNMOUNT_TRANS,
920 },
921 .ulf = {
922 .magic = XLOG_UNMOUNT_TYPE,
923 },
924 };
925 struct xfs_log_iovec reg = {
926 .i_addr = &unmount_rec,
927 .i_len = sizeof(unmount_rec),
928 .i_type = XLOG_REG_TYPE_UNMOUNT,
929 };
930 struct xfs_log_vec vec = {
931 .lv_niovecs = 1,
932 .lv_iovecp = ®,
933 };
934 LIST_HEAD(lv_chain);
935 list_add(&vec.lv_list, &lv_chain);
936
937 BUILD_BUG_ON((sizeof(struct xlog_op_header) +
938 sizeof(struct xfs_unmount_log_format)) !=
939 sizeof(unmount_rec));
940
941 /* account for space used by record data */
942 ticket->t_curr_res -= sizeof(unmount_rec);
943
944 return xlog_write(log, NULL, &lv_chain, ticket, reg.i_len);
945}
946
947/*
948 * Mark the filesystem clean by writing an unmount record to the head of the
949 * log.
950 */
951static void
952xlog_unmount_write(
953 struct xlog *log)
954{
955 struct xfs_mount *mp = log->l_mp;
956 struct xlog_in_core *iclog;
957 struct xlog_ticket *tic = NULL;
958 int error;
959
960 error = xfs_log_reserve(mp, 600, 1, &tic, 0);
961 if (error)
962 goto out_err;
963
964 error = xlog_write_unmount_record(log, tic);
965 /*
966 * At this point, we're umounting anyway, so there's no point in
967 * transitioning log state to shutdown. Just continue...
968 */
969out_err:
970 if (error)
971 xfs_alert(mp, "%s: unmount record failed", __func__);
972
973 spin_lock(&log->l_icloglock);
974 iclog = log->l_iclog;
975 error = xlog_force_iclog(iclog);
976 xlog_wait_on_iclog(iclog);
977
978 if (tic) {
979 trace_xfs_log_umount_write(log, tic);
980 xfs_log_ticket_ungrant(log, tic);
981 }
982}
983
984static void
985xfs_log_unmount_verify_iclog(
986 struct xlog *log)
987{
988 struct xlog_in_core *iclog = log->l_iclog;
989
990 do {
991 ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE);
992 ASSERT(iclog->ic_offset == 0);
993 } while ((iclog = iclog->ic_next) != log->l_iclog);
994}
995
996/*
997 * Unmount record used to have a string "Unmount filesystem--" in the
998 * data section where the "Un" was really a magic number (XLOG_UNMOUNT_TYPE).
999 * We just write the magic number now since that particular field isn't
1000 * currently architecture converted and "Unmount" is a bit foo.
1001 * As far as I know, there weren't any dependencies on the old behaviour.
1002 */
1003static void
1004xfs_log_unmount_write(
1005 struct xfs_mount *mp)
1006{
1007 struct xlog *log = mp->m_log;
1008
1009 if (!xfs_log_writable(mp))
1010 return;
1011
1012 xfs_log_force(mp, XFS_LOG_SYNC);
1013
1014 if (xlog_is_shutdown(log))
1015 return;
1016
1017 /*
1018 * If we think the summary counters are bad, avoid writing the unmount
1019 * record to force log recovery at next mount, after which the summary
1020 * counters will be recalculated. Refer to xlog_check_unmount_rec for
1021 * more details.
1022 */
1023 if (XFS_TEST_ERROR(xfs_fs_has_sickness(mp, XFS_SICK_FS_COUNTERS), mp,
1024 XFS_ERRTAG_FORCE_SUMMARY_RECALC)) {
1025 xfs_alert(mp, "%s: will fix summary counters at next mount",
1026 __func__);
1027 return;
1028 }
1029
1030 xfs_log_unmount_verify_iclog(log);
1031 xlog_unmount_write(log);
1032}
1033
1034/*
1035 * Empty the log for unmount/freeze.
1036 *
1037 * To do this, we first need to shut down the background log work so it is not
1038 * trying to cover the log as we clean up. We then need to unpin all objects in
1039 * the log so we can then flush them out. Once they have completed their IO and
1040 * run the callbacks removing themselves from the AIL, we can cover the log.
1041 */
1042int
1043xfs_log_quiesce(
1044 struct xfs_mount *mp)
1045{
1046 /*
1047 * Clear log incompat features since we're quiescing the log. Report
1048 * failures, though it's not fatal to have a higher log feature
1049 * protection level than the log contents actually require.
1050 */
1051 if (xfs_clear_incompat_log_features(mp)) {
1052 int error;
1053
1054 error = xfs_sync_sb(mp, false);
1055 if (error)
1056 xfs_warn(mp,
1057 "Failed to clear log incompat features on quiesce");
1058 }
1059
1060 cancel_delayed_work_sync(&mp->m_log->l_work);
1061 xfs_log_force(mp, XFS_LOG_SYNC);
1062
1063 /*
1064 * The superblock buffer is uncached and while xfs_ail_push_all_sync()
1065 * will push it, xfs_buftarg_wait() will not wait for it. Further,
1066 * xfs_buf_iowait() cannot be used because it was pushed with the
1067 * XBF_ASYNC flag set, so we need to use a lock/unlock pair to wait for
1068 * the IO to complete.
1069 */
1070 xfs_ail_push_all_sync(mp->m_ail);
1071 xfs_buftarg_wait(mp->m_ddev_targp);
1072 xfs_buf_lock(mp->m_sb_bp);
1073 xfs_buf_unlock(mp->m_sb_bp);
1074
1075 return xfs_log_cover(mp);
1076}
1077
1078void
1079xfs_log_clean(
1080 struct xfs_mount *mp)
1081{
1082 xfs_log_quiesce(mp);
1083 xfs_log_unmount_write(mp);
1084}
1085
1086/*
1087 * Shut down and release the AIL and Log.
1088 *
1089 * During unmount, we need to ensure we flush all the dirty metadata objects
1090 * from the AIL so that the log is empty before we write the unmount record to
1091 * the log. Once this is done, we can tear down the AIL and the log.
1092 */
1093void
1094xfs_log_unmount(
1095 struct xfs_mount *mp)
1096{
1097 xfs_log_clean(mp);
1098
1099 /*
1100 * If shutdown has come from iclog IO context, the log
1101 * cleaning will have been skipped and so we need to wait
1102 * for the iclog to complete shutdown processing before we
1103 * tear anything down.
1104 */
1105 xlog_wait_iclog_completion(mp->m_log);
1106
1107 xfs_buftarg_drain(mp->m_ddev_targp);
1108
1109 xfs_trans_ail_destroy(mp);
1110
1111 xfs_sysfs_del(&mp->m_log->l_kobj);
1112
1113 xlog_dealloc_log(mp->m_log);
1114}
1115
1116void
1117xfs_log_item_init(
1118 struct xfs_mount *mp,
1119 struct xfs_log_item *item,
1120 int type,
1121 const struct xfs_item_ops *ops)
1122{
1123 item->li_log = mp->m_log;
1124 item->li_ailp = mp->m_ail;
1125 item->li_type = type;
1126 item->li_ops = ops;
1127 item->li_lv = NULL;
1128
1129 INIT_LIST_HEAD(&item->li_ail);
1130 INIT_LIST_HEAD(&item->li_cil);
1131 INIT_LIST_HEAD(&item->li_bio_list);
1132 INIT_LIST_HEAD(&item->li_trans);
1133}
1134
1135/*
1136 * Wake up processes waiting for log space after we have moved the log tail.
1137 */
1138void
1139xfs_log_space_wake(
1140 struct xfs_mount *mp)
1141{
1142 struct xlog *log = mp->m_log;
1143 int free_bytes;
1144
1145 if (xlog_is_shutdown(log))
1146 return;
1147
1148 if (!list_empty_careful(&log->l_write_head.waiters)) {
1149 ASSERT(!xlog_in_recovery(log));
1150
1151 spin_lock(&log->l_write_head.lock);
1152 free_bytes = xlog_space_left(log, &log->l_write_head.grant);
1153 xlog_grant_head_wake(log, &log->l_write_head, &free_bytes);
1154 spin_unlock(&log->l_write_head.lock);
1155 }
1156
1157 if (!list_empty_careful(&log->l_reserve_head.waiters)) {
1158 ASSERT(!xlog_in_recovery(log));
1159
1160 spin_lock(&log->l_reserve_head.lock);
1161 free_bytes = xlog_space_left(log, &log->l_reserve_head.grant);
1162 xlog_grant_head_wake(log, &log->l_reserve_head, &free_bytes);
1163 spin_unlock(&log->l_reserve_head.lock);
1164 }
1165}
1166
1167/*
1168 * Determine if we have a transaction that has gone to disk that needs to be
1169 * covered. To begin the transition to the idle state firstly the log needs to
1170 * be idle. That means the CIL, the AIL and the iclogs needs to be empty before
1171 * we start attempting to cover the log.
1172 *
1173 * Only if we are then in a state where covering is needed, the caller is
1174 * informed that dummy transactions are required to move the log into the idle
1175 * state.
1176 *
1177 * If there are any items in the AIl or CIL, then we do not want to attempt to
1178 * cover the log as we may be in a situation where there isn't log space
1179 * available to run a dummy transaction and this can lead to deadlocks when the
1180 * tail of the log is pinned by an item that is modified in the CIL. Hence
1181 * there's no point in running a dummy transaction at this point because we
1182 * can't start trying to idle the log until both the CIL and AIL are empty.
1183 */
1184static bool
1185xfs_log_need_covered(
1186 struct xfs_mount *mp)
1187{
1188 struct xlog *log = mp->m_log;
1189 bool needed = false;
1190
1191 if (!xlog_cil_empty(log))
1192 return false;
1193
1194 spin_lock(&log->l_icloglock);
1195 switch (log->l_covered_state) {
1196 case XLOG_STATE_COVER_DONE:
1197 case XLOG_STATE_COVER_DONE2:
1198 case XLOG_STATE_COVER_IDLE:
1199 break;
1200 case XLOG_STATE_COVER_NEED:
1201 case XLOG_STATE_COVER_NEED2:
1202 if (xfs_ail_min_lsn(log->l_ailp))
1203 break;
1204 if (!xlog_iclogs_empty(log))
1205 break;
1206
1207 needed = true;
1208 if (log->l_covered_state == XLOG_STATE_COVER_NEED)
1209 log->l_covered_state = XLOG_STATE_COVER_DONE;
1210 else
1211 log->l_covered_state = XLOG_STATE_COVER_DONE2;
1212 break;
1213 default:
1214 needed = true;
1215 break;
1216 }
1217 spin_unlock(&log->l_icloglock);
1218 return needed;
1219}
1220
1221/*
1222 * Explicitly cover the log. This is similar to background log covering but
1223 * intended for usage in quiesce codepaths. The caller is responsible to ensure
1224 * the log is idle and suitable for covering. The CIL, iclog buffers and AIL
1225 * must all be empty.
1226 */
1227static int
1228xfs_log_cover(
1229 struct xfs_mount *mp)
1230{
1231 int error = 0;
1232 bool need_covered;
1233
1234 ASSERT((xlog_cil_empty(mp->m_log) && xlog_iclogs_empty(mp->m_log) &&
1235 !xfs_ail_min_lsn(mp->m_log->l_ailp)) ||
1236 xlog_is_shutdown(mp->m_log));
1237
1238 if (!xfs_log_writable(mp))
1239 return 0;
1240
1241 /*
1242 * xfs_log_need_covered() is not idempotent because it progresses the
1243 * state machine if the log requires covering. Therefore, we must call
1244 * this function once and use the result until we've issued an sb sync.
1245 * Do so first to make that abundantly clear.
1246 *
1247 * Fall into the covering sequence if the log needs covering or the
1248 * mount has lazy superblock accounting to sync to disk. The sb sync
1249 * used for covering accumulates the in-core counters, so covering
1250 * handles this for us.
1251 */
1252 need_covered = xfs_log_need_covered(mp);
1253 if (!need_covered && !xfs_has_lazysbcount(mp))
1254 return 0;
1255
1256 /*
1257 * To cover the log, commit the superblock twice (at most) in
1258 * independent checkpoints. The first serves as a reference for the
1259 * tail pointer. The sync transaction and AIL push empties the AIL and
1260 * updates the in-core tail to the LSN of the first checkpoint. The
1261 * second commit updates the on-disk tail with the in-core LSN,
1262 * covering the log. Push the AIL one more time to leave it empty, as
1263 * we found it.
1264 */
1265 do {
1266 error = xfs_sync_sb(mp, true);
1267 if (error)
1268 break;
1269 xfs_ail_push_all_sync(mp->m_ail);
1270 } while (xfs_log_need_covered(mp));
1271
1272 return error;
1273}
1274
1275/*
1276 * We may be holding the log iclog lock upon entering this routine.
1277 */
1278xfs_lsn_t
1279xlog_assign_tail_lsn_locked(
1280 struct xfs_mount *mp)
1281{
1282 struct xlog *log = mp->m_log;
1283 struct xfs_log_item *lip;
1284 xfs_lsn_t tail_lsn;
1285
1286 assert_spin_locked(&mp->m_ail->ail_lock);
1287
1288 /*
1289 * To make sure we always have a valid LSN for the log tail we keep
1290 * track of the last LSN which was committed in log->l_last_sync_lsn,
1291 * and use that when the AIL was empty.
1292 */
1293 lip = xfs_ail_min(mp->m_ail);
1294 if (lip)
1295 tail_lsn = lip->li_lsn;
1296 else
1297 tail_lsn = atomic64_read(&log->l_last_sync_lsn);
1298 trace_xfs_log_assign_tail_lsn(log, tail_lsn);
1299 atomic64_set(&log->l_tail_lsn, tail_lsn);
1300 return tail_lsn;
1301}
1302
1303xfs_lsn_t
1304xlog_assign_tail_lsn(
1305 struct xfs_mount *mp)
1306{
1307 xfs_lsn_t tail_lsn;
1308
1309 spin_lock(&mp->m_ail->ail_lock);
1310 tail_lsn = xlog_assign_tail_lsn_locked(mp);
1311 spin_unlock(&mp->m_ail->ail_lock);
1312
1313 return tail_lsn;
1314}
1315
1316/*
1317 * Return the space in the log between the tail and the head. The head
1318 * is passed in the cycle/bytes formal parms. In the special case where
1319 * the reserve head has wrapped passed the tail, this calculation is no
1320 * longer valid. In this case, just return 0 which means there is no space
1321 * in the log. This works for all places where this function is called
1322 * with the reserve head. Of course, if the write head were to ever
1323 * wrap the tail, we should blow up. Rather than catch this case here,
1324 * we depend on other ASSERTions in other parts of the code. XXXmiken
1325 *
1326 * If reservation head is behind the tail, we have a problem. Warn about it,
1327 * but then treat it as if the log is empty.
1328 *
1329 * If the log is shut down, the head and tail may be invalid or out of whack, so
1330 * shortcut invalidity asserts in this case so that we don't trigger them
1331 * falsely.
1332 */
1333STATIC int
1334xlog_space_left(
1335 struct xlog *log,
1336 atomic64_t *head)
1337{
1338 int tail_bytes;
1339 int tail_cycle;
1340 int head_cycle;
1341 int head_bytes;
1342
1343 xlog_crack_grant_head(head, &head_cycle, &head_bytes);
1344 xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_bytes);
1345 tail_bytes = BBTOB(tail_bytes);
1346 if (tail_cycle == head_cycle && head_bytes >= tail_bytes)
1347 return log->l_logsize - (head_bytes - tail_bytes);
1348 if (tail_cycle + 1 < head_cycle)
1349 return 0;
1350
1351 /* Ignore potential inconsistency when shutdown. */
1352 if (xlog_is_shutdown(log))
1353 return log->l_logsize;
1354
1355 if (tail_cycle < head_cycle) {
1356 ASSERT(tail_cycle == (head_cycle - 1));
1357 return tail_bytes - head_bytes;
1358 }
1359
1360 /*
1361 * The reservation head is behind the tail. In this case we just want to
1362 * return the size of the log as the amount of space left.
1363 */
1364 xfs_alert(log->l_mp, "xlog_space_left: head behind tail");
1365 xfs_alert(log->l_mp, " tail_cycle = %d, tail_bytes = %d",
1366 tail_cycle, tail_bytes);
1367 xfs_alert(log->l_mp, " GH cycle = %d, GH bytes = %d",
1368 head_cycle, head_bytes);
1369 ASSERT(0);
1370 return log->l_logsize;
1371}
1372
1373
1374static void
1375xlog_ioend_work(
1376 struct work_struct *work)
1377{
1378 struct xlog_in_core *iclog =
1379 container_of(work, struct xlog_in_core, ic_end_io_work);
1380 struct xlog *log = iclog->ic_log;
1381 int error;
1382
1383 error = blk_status_to_errno(iclog->ic_bio.bi_status);
1384#ifdef DEBUG
1385 /* treat writes with injected CRC errors as failed */
1386 if (iclog->ic_fail_crc)
1387 error = -EIO;
1388#endif
1389
1390 /*
1391 * Race to shutdown the filesystem if we see an error.
1392 */
1393 if (XFS_TEST_ERROR(error, log->l_mp, XFS_ERRTAG_IODONE_IOERR)) {
1394 xfs_alert(log->l_mp, "log I/O error %d", error);
1395 xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
1396 }
1397
1398 xlog_state_done_syncing(iclog);
1399 bio_uninit(&iclog->ic_bio);
1400
1401 /*
1402 * Drop the lock to signal that we are done. Nothing references the
1403 * iclog after this, so an unmount waiting on this lock can now tear it
1404 * down safely. As such, it is unsafe to reference the iclog after the
1405 * unlock as we could race with it being freed.
1406 */
1407 up(&iclog->ic_sema);
1408}
1409
1410/*
1411 * Return size of each in-core log record buffer.
1412 *
1413 * All machines get 8 x 32kB buffers by default, unless tuned otherwise.
1414 *
1415 * If the filesystem blocksize is too large, we may need to choose a
1416 * larger size since the directory code currently logs entire blocks.
1417 */
1418STATIC void
1419xlog_get_iclog_buffer_size(
1420 struct xfs_mount *mp,
1421 struct xlog *log)
1422{
1423 if (mp->m_logbufs <= 0)
1424 mp->m_logbufs = XLOG_MAX_ICLOGS;
1425 if (mp->m_logbsize <= 0)
1426 mp->m_logbsize = XLOG_BIG_RECORD_BSIZE;
1427
1428 log->l_iclog_bufs = mp->m_logbufs;
1429 log->l_iclog_size = mp->m_logbsize;
1430
1431 /*
1432 * # headers = size / 32k - one header holds cycles from 32k of data.
1433 */
1434 log->l_iclog_heads =
1435 DIV_ROUND_UP(mp->m_logbsize, XLOG_HEADER_CYCLE_SIZE);
1436 log->l_iclog_hsize = log->l_iclog_heads << BBSHIFT;
1437}
1438
1439void
1440xfs_log_work_queue(
1441 struct xfs_mount *mp)
1442{
1443 queue_delayed_work(mp->m_sync_workqueue, &mp->m_log->l_work,
1444 msecs_to_jiffies(xfs_syncd_centisecs * 10));
1445}
1446
1447/*
1448 * Clear the log incompat flags if we have the opportunity.
1449 *
1450 * This only happens if we're about to log the second dummy transaction as part
1451 * of covering the log and we can get the log incompat feature usage lock.
1452 */
1453static inline void
1454xlog_clear_incompat(
1455 struct xlog *log)
1456{
1457 struct xfs_mount *mp = log->l_mp;
1458
1459 if (!xfs_sb_has_incompat_log_feature(&mp->m_sb,
1460 XFS_SB_FEAT_INCOMPAT_LOG_ALL))
1461 return;
1462
1463 if (log->l_covered_state != XLOG_STATE_COVER_DONE2)
1464 return;
1465
1466 if (!down_write_trylock(&log->l_incompat_users))
1467 return;
1468
1469 xfs_clear_incompat_log_features(mp);
1470 up_write(&log->l_incompat_users);
1471}
1472
1473/*
1474 * Every sync period we need to unpin all items in the AIL and push them to
1475 * disk. If there is nothing dirty, then we might need to cover the log to
1476 * indicate that the filesystem is idle.
1477 */
1478static void
1479xfs_log_worker(
1480 struct work_struct *work)
1481{
1482 struct xlog *log = container_of(to_delayed_work(work),
1483 struct xlog, l_work);
1484 struct xfs_mount *mp = log->l_mp;
1485
1486 /* dgc: errors ignored - not fatal and nowhere to report them */
1487 if (xfs_fs_writable(mp, SB_FREEZE_WRITE) && xfs_log_need_covered(mp)) {
1488 /*
1489 * Dump a transaction into the log that contains no real change.
1490 * This is needed to stamp the current tail LSN into the log
1491 * during the covering operation.
1492 *
1493 * We cannot use an inode here for this - that will push dirty
1494 * state back up into the VFS and then periodic inode flushing
1495 * will prevent log covering from making progress. Hence we
1496 * synchronously log the superblock instead to ensure the
1497 * superblock is immediately unpinned and can be written back.
1498 */
1499 xlog_clear_incompat(log);
1500 xfs_sync_sb(mp, true);
1501 } else
1502 xfs_log_force(mp, 0);
1503
1504 /* start pushing all the metadata that is currently dirty */
1505 xfs_ail_push_all(mp->m_ail);
1506
1507 /* queue us up again */
1508 xfs_log_work_queue(mp);
1509}
1510
1511/*
1512 * This routine initializes some of the log structure for a given mount point.
1513 * Its primary purpose is to fill in enough, so recovery can occur. However,
1514 * some other stuff may be filled in too.
1515 */
1516STATIC struct xlog *
1517xlog_alloc_log(
1518 struct xfs_mount *mp,
1519 struct xfs_buftarg *log_target,
1520 xfs_daddr_t blk_offset,
1521 int num_bblks)
1522{
1523 struct xlog *log;
1524 xlog_rec_header_t *head;
1525 xlog_in_core_t **iclogp;
1526 xlog_in_core_t *iclog, *prev_iclog=NULL;
1527 int i;
1528 int error = -ENOMEM;
1529 uint log2_size = 0;
1530
1531 log = kmem_zalloc(sizeof(struct xlog), KM_MAYFAIL);
1532 if (!log) {
1533 xfs_warn(mp, "Log allocation failed: No memory!");
1534 goto out;
1535 }
1536
1537 log->l_mp = mp;
1538 log->l_targ = log_target;
1539 log->l_logsize = BBTOB(num_bblks);
1540 log->l_logBBstart = blk_offset;
1541 log->l_logBBsize = num_bblks;
1542 log->l_covered_state = XLOG_STATE_COVER_IDLE;
1543 set_bit(XLOG_ACTIVE_RECOVERY, &log->l_opstate);
1544 INIT_DELAYED_WORK(&log->l_work, xfs_log_worker);
1545 INIT_LIST_HEAD(&log->r_dfops);
1546
1547 log->l_prev_block = -1;
1548 /* log->l_tail_lsn = 0x100000000LL; cycle = 1; current block = 0 */
1549 xlog_assign_atomic_lsn(&log->l_tail_lsn, 1, 0);
1550 xlog_assign_atomic_lsn(&log->l_last_sync_lsn, 1, 0);
1551 log->l_curr_cycle = 1; /* 0 is bad since this is initial value */
1552
1553 if (xfs_has_logv2(mp) && mp->m_sb.sb_logsunit > 1)
1554 log->l_iclog_roundoff = mp->m_sb.sb_logsunit;
1555 else
1556 log->l_iclog_roundoff = BBSIZE;
1557
1558 xlog_grant_head_init(&log->l_reserve_head);
1559 xlog_grant_head_init(&log->l_write_head);
1560
1561 error = -EFSCORRUPTED;
1562 if (xfs_has_sector(mp)) {
1563 log2_size = mp->m_sb.sb_logsectlog;
1564 if (log2_size < BBSHIFT) {
1565 xfs_warn(mp, "Log sector size too small (0x%x < 0x%x)",
1566 log2_size, BBSHIFT);
1567 goto out_free_log;
1568 }
1569
1570 log2_size -= BBSHIFT;
1571 if (log2_size > mp->m_sectbb_log) {
1572 xfs_warn(mp, "Log sector size too large (0x%x > 0x%x)",
1573 log2_size, mp->m_sectbb_log);
1574 goto out_free_log;
1575 }
1576
1577 /* for larger sector sizes, must have v2 or external log */
1578 if (log2_size && log->l_logBBstart > 0 &&
1579 !xfs_has_logv2(mp)) {
1580 xfs_warn(mp,
1581 "log sector size (0x%x) invalid for configuration.",
1582 log2_size);
1583 goto out_free_log;
1584 }
1585 }
1586 log->l_sectBBsize = 1 << log2_size;
1587
1588 init_rwsem(&log->l_incompat_users);
1589
1590 xlog_get_iclog_buffer_size(mp, log);
1591
1592 spin_lock_init(&log->l_icloglock);
1593 init_waitqueue_head(&log->l_flush_wait);
1594
1595 iclogp = &log->l_iclog;
1596 /*
1597 * The amount of memory to allocate for the iclog structure is
1598 * rather funky due to the way the structure is defined. It is
1599 * done this way so that we can use different sizes for machines
1600 * with different amounts of memory. See the definition of
1601 * xlog_in_core_t in xfs_log_priv.h for details.
1602 */
1603 ASSERT(log->l_iclog_size >= 4096);
1604 for (i = 0; i < log->l_iclog_bufs; i++) {
1605 size_t bvec_size = howmany(log->l_iclog_size, PAGE_SIZE) *
1606 sizeof(struct bio_vec);
1607
1608 iclog = kmem_zalloc(sizeof(*iclog) + bvec_size, KM_MAYFAIL);
1609 if (!iclog)
1610 goto out_free_iclog;
1611
1612 *iclogp = iclog;
1613 iclog->ic_prev = prev_iclog;
1614 prev_iclog = iclog;
1615
1616 iclog->ic_data = kvzalloc(log->l_iclog_size,
1617 GFP_KERNEL | __GFP_RETRY_MAYFAIL);
1618 if (!iclog->ic_data)
1619 goto out_free_iclog;
1620 head = &iclog->ic_header;
1621 memset(head, 0, sizeof(xlog_rec_header_t));
1622 head->h_magicno = cpu_to_be32(XLOG_HEADER_MAGIC_NUM);
1623 head->h_version = cpu_to_be32(
1624 xfs_has_logv2(log->l_mp) ? 2 : 1);
1625 head->h_size = cpu_to_be32(log->l_iclog_size);
1626 /* new fields */
1627 head->h_fmt = cpu_to_be32(XLOG_FMT);
1628 memcpy(&head->h_fs_uuid, &mp->m_sb.sb_uuid, sizeof(uuid_t));
1629
1630 iclog->ic_size = log->l_iclog_size - log->l_iclog_hsize;
1631 iclog->ic_state = XLOG_STATE_ACTIVE;
1632 iclog->ic_log = log;
1633 atomic_set(&iclog->ic_refcnt, 0);
1634 INIT_LIST_HEAD(&iclog->ic_callbacks);
1635 iclog->ic_datap = (void *)iclog->ic_data + log->l_iclog_hsize;
1636
1637 init_waitqueue_head(&iclog->ic_force_wait);
1638 init_waitqueue_head(&iclog->ic_write_wait);
1639 INIT_WORK(&iclog->ic_end_io_work, xlog_ioend_work);
1640 sema_init(&iclog->ic_sema, 1);
1641
1642 iclogp = &iclog->ic_next;
1643 }
1644 *iclogp = log->l_iclog; /* complete ring */
1645 log->l_iclog->ic_prev = prev_iclog; /* re-write 1st prev ptr */
1646
1647 log->l_ioend_workqueue = alloc_workqueue("xfs-log/%s",
1648 XFS_WQFLAGS(WQ_FREEZABLE | WQ_MEM_RECLAIM |
1649 WQ_HIGHPRI),
1650 0, mp->m_super->s_id);
1651 if (!log->l_ioend_workqueue)
1652 goto out_free_iclog;
1653
1654 error = xlog_cil_init(log);
1655 if (error)
1656 goto out_destroy_workqueue;
1657 return log;
1658
1659out_destroy_workqueue:
1660 destroy_workqueue(log->l_ioend_workqueue);
1661out_free_iclog:
1662 for (iclog = log->l_iclog; iclog; iclog = prev_iclog) {
1663 prev_iclog = iclog->ic_next;
1664 kmem_free(iclog->ic_data);
1665 kmem_free(iclog);
1666 if (prev_iclog == log->l_iclog)
1667 break;
1668 }
1669out_free_log:
1670 kmem_free(log);
1671out:
1672 return ERR_PTR(error);
1673} /* xlog_alloc_log */
1674
1675/*
1676 * Compute the LSN that we'd need to push the log tail towards in order to have
1677 * (a) enough on-disk log space to log the number of bytes specified, (b) at
1678 * least 25% of the log space free, and (c) at least 256 blocks free. If the
1679 * log free space already meets all three thresholds, this function returns
1680 * NULLCOMMITLSN.
1681 */
1682xfs_lsn_t
1683xlog_grant_push_threshold(
1684 struct xlog *log,
1685 int need_bytes)
1686{
1687 xfs_lsn_t threshold_lsn = 0;
1688 xfs_lsn_t last_sync_lsn;
1689 int free_blocks;
1690 int free_bytes;
1691 int threshold_block;
1692 int threshold_cycle;
1693 int free_threshold;
1694
1695 ASSERT(BTOBB(need_bytes) < log->l_logBBsize);
1696
1697 free_bytes = xlog_space_left(log, &log->l_reserve_head.grant);
1698 free_blocks = BTOBBT(free_bytes);
1699
1700 /*
1701 * Set the threshold for the minimum number of free blocks in the
1702 * log to the maximum of what the caller needs, one quarter of the
1703 * log, and 256 blocks.
1704 */
1705 free_threshold = BTOBB(need_bytes);
1706 free_threshold = max(free_threshold, (log->l_logBBsize >> 2));
1707 free_threshold = max(free_threshold, 256);
1708 if (free_blocks >= free_threshold)
1709 return NULLCOMMITLSN;
1710
1711 xlog_crack_atomic_lsn(&log->l_tail_lsn, &threshold_cycle,
1712 &threshold_block);
1713 threshold_block += free_threshold;
1714 if (threshold_block >= log->l_logBBsize) {
1715 threshold_block -= log->l_logBBsize;
1716 threshold_cycle += 1;
1717 }
1718 threshold_lsn = xlog_assign_lsn(threshold_cycle,
1719 threshold_block);
1720 /*
1721 * Don't pass in an lsn greater than the lsn of the last
1722 * log record known to be on disk. Use a snapshot of the last sync lsn
1723 * so that it doesn't change between the compare and the set.
1724 */
1725 last_sync_lsn = atomic64_read(&log->l_last_sync_lsn);
1726 if (XFS_LSN_CMP(threshold_lsn, last_sync_lsn) > 0)
1727 threshold_lsn = last_sync_lsn;
1728
1729 return threshold_lsn;
1730}
1731
1732/*
1733 * Push the tail of the log if we need to do so to maintain the free log space
1734 * thresholds set out by xlog_grant_push_threshold. We may need to adopt a
1735 * policy which pushes on an lsn which is further along in the log once we
1736 * reach the high water mark. In this manner, we would be creating a low water
1737 * mark.
1738 */
1739STATIC void
1740xlog_grant_push_ail(
1741 struct xlog *log,
1742 int need_bytes)
1743{
1744 xfs_lsn_t threshold_lsn;
1745
1746 threshold_lsn = xlog_grant_push_threshold(log, need_bytes);
1747 if (threshold_lsn == NULLCOMMITLSN || xlog_is_shutdown(log))
1748 return;
1749
1750 /*
1751 * Get the transaction layer to kick the dirty buffers out to
1752 * disk asynchronously. No point in trying to do this if
1753 * the filesystem is shutting down.
1754 */
1755 xfs_ail_push(log->l_ailp, threshold_lsn);
1756}
1757
1758/*
1759 * Stamp cycle number in every block
1760 */
1761STATIC void
1762xlog_pack_data(
1763 struct xlog *log,
1764 struct xlog_in_core *iclog,
1765 int roundoff)
1766{
1767 int i, j, k;
1768 int size = iclog->ic_offset + roundoff;
1769 __be32 cycle_lsn;
1770 char *dp;
1771
1772 cycle_lsn = CYCLE_LSN_DISK(iclog->ic_header.h_lsn);
1773
1774 dp = iclog->ic_datap;
1775 for (i = 0; i < BTOBB(size); i++) {
1776 if (i >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE))
1777 break;
1778 iclog->ic_header.h_cycle_data[i] = *(__be32 *)dp;
1779 *(__be32 *)dp = cycle_lsn;
1780 dp += BBSIZE;
1781 }
1782
1783 if (xfs_has_logv2(log->l_mp)) {
1784 xlog_in_core_2_t *xhdr = iclog->ic_data;
1785
1786 for ( ; i < BTOBB(size); i++) {
1787 j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
1788 k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
1789 xhdr[j].hic_xheader.xh_cycle_data[k] = *(__be32 *)dp;
1790 *(__be32 *)dp = cycle_lsn;
1791 dp += BBSIZE;
1792 }
1793
1794 for (i = 1; i < log->l_iclog_heads; i++)
1795 xhdr[i].hic_xheader.xh_cycle = cycle_lsn;
1796 }
1797}
1798
1799/*
1800 * Calculate the checksum for a log buffer.
1801 *
1802 * This is a little more complicated than it should be because the various
1803 * headers and the actual data are non-contiguous.
1804 */
1805__le32
1806xlog_cksum(
1807 struct xlog *log,
1808 struct xlog_rec_header *rhead,
1809 char *dp,
1810 int size)
1811{
1812 uint32_t crc;
1813
1814 /* first generate the crc for the record header ... */
1815 crc = xfs_start_cksum_update((char *)rhead,
1816 sizeof(struct xlog_rec_header),
1817 offsetof(struct xlog_rec_header, h_crc));
1818
1819 /* ... then for additional cycle data for v2 logs ... */
1820 if (xfs_has_logv2(log->l_mp)) {
1821 union xlog_in_core2 *xhdr = (union xlog_in_core2 *)rhead;
1822 int i;
1823 int xheads;
1824
1825 xheads = DIV_ROUND_UP(size, XLOG_HEADER_CYCLE_SIZE);
1826
1827 for (i = 1; i < xheads; i++) {
1828 crc = crc32c(crc, &xhdr[i].hic_xheader,
1829 sizeof(struct xlog_rec_ext_header));
1830 }
1831 }
1832
1833 /* ... and finally for the payload */
1834 crc = crc32c(crc, dp, size);
1835
1836 return xfs_end_cksum(crc);
1837}
1838
1839static void
1840xlog_bio_end_io(
1841 struct bio *bio)
1842{
1843 struct xlog_in_core *iclog = bio->bi_private;
1844
1845 queue_work(iclog->ic_log->l_ioend_workqueue,
1846 &iclog->ic_end_io_work);
1847}
1848
1849static int
1850xlog_map_iclog_data(
1851 struct bio *bio,
1852 void *data,
1853 size_t count)
1854{
1855 do {
1856 struct page *page = kmem_to_page(data);
1857 unsigned int off = offset_in_page(data);
1858 size_t len = min_t(size_t, count, PAGE_SIZE - off);
1859
1860 if (bio_add_page(bio, page, len, off) != len)
1861 return -EIO;
1862
1863 data += len;
1864 count -= len;
1865 } while (count);
1866
1867 return 0;
1868}
1869
1870STATIC void
1871xlog_write_iclog(
1872 struct xlog *log,
1873 struct xlog_in_core *iclog,
1874 uint64_t bno,
1875 unsigned int count)
1876{
1877 ASSERT(bno < log->l_logBBsize);
1878 trace_xlog_iclog_write(iclog, _RET_IP_);
1879
1880 /*
1881 * We lock the iclogbufs here so that we can serialise against I/O
1882 * completion during unmount. We might be processing a shutdown
1883 * triggered during unmount, and that can occur asynchronously to the
1884 * unmount thread, and hence we need to ensure that completes before
1885 * tearing down the iclogbufs. Hence we need to hold the buffer lock
1886 * across the log IO to archieve that.
1887 */
1888 down(&iclog->ic_sema);
1889 if (xlog_is_shutdown(log)) {
1890 /*
1891 * It would seem logical to return EIO here, but we rely on
1892 * the log state machine to propagate I/O errors instead of
1893 * doing it here. We kick of the state machine and unlock
1894 * the buffer manually, the code needs to be kept in sync
1895 * with the I/O completion path.
1896 */
1897 goto sync;
1898 }
1899
1900 /*
1901 * We use REQ_SYNC | REQ_IDLE here to tell the block layer the are more
1902 * IOs coming immediately after this one. This prevents the block layer
1903 * writeback throttle from throttling log writes behind background
1904 * metadata writeback and causing priority inversions.
1905 */
1906 bio_init(&iclog->ic_bio, log->l_targ->bt_bdev, iclog->ic_bvec,
1907 howmany(count, PAGE_SIZE),
1908 REQ_OP_WRITE | REQ_META | REQ_SYNC | REQ_IDLE);
1909 iclog->ic_bio.bi_iter.bi_sector = log->l_logBBstart + bno;
1910 iclog->ic_bio.bi_end_io = xlog_bio_end_io;
1911 iclog->ic_bio.bi_private = iclog;
1912
1913 if (iclog->ic_flags & XLOG_ICL_NEED_FLUSH) {
1914 iclog->ic_bio.bi_opf |= REQ_PREFLUSH;
1915 /*
1916 * For external log devices, we also need to flush the data
1917 * device cache first to ensure all metadata writeback covered
1918 * by the LSN in this iclog is on stable storage. This is slow,
1919 * but it *must* complete before we issue the external log IO.
1920 *
1921 * If the flush fails, we cannot conclude that past metadata
1922 * writeback from the log succeeded. Repeating the flush is
1923 * not possible, hence we must shut down with log IO error to
1924 * avoid shutdown re-entering this path and erroring out again.
1925 */
1926 if (log->l_targ != log->l_mp->m_ddev_targp &&
1927 blkdev_issue_flush(log->l_mp->m_ddev_targp->bt_bdev))
1928 goto shutdown;
1929 }
1930 if (iclog->ic_flags & XLOG_ICL_NEED_FUA)
1931 iclog->ic_bio.bi_opf |= REQ_FUA;
1932
1933 iclog->ic_flags &= ~(XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA);
1934
1935 if (xlog_map_iclog_data(&iclog->ic_bio, iclog->ic_data, count))
1936 goto shutdown;
1937
1938 if (is_vmalloc_addr(iclog->ic_data))
1939 flush_kernel_vmap_range(iclog->ic_data, count);
1940
1941 /*
1942 * If this log buffer would straddle the end of the log we will have
1943 * to split it up into two bios, so that we can continue at the start.
1944 */
1945 if (bno + BTOBB(count) > log->l_logBBsize) {
1946 struct bio *split;
1947
1948 split = bio_split(&iclog->ic_bio, log->l_logBBsize - bno,
1949 GFP_NOIO, &fs_bio_set);
1950 bio_chain(split, &iclog->ic_bio);
1951 submit_bio(split);
1952
1953 /* restart at logical offset zero for the remainder */
1954 iclog->ic_bio.bi_iter.bi_sector = log->l_logBBstart;
1955 }
1956
1957 submit_bio(&iclog->ic_bio);
1958 return;
1959shutdown:
1960 xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
1961sync:
1962 xlog_state_done_syncing(iclog);
1963 up(&iclog->ic_sema);
1964}
1965
1966/*
1967 * We need to bump cycle number for the part of the iclog that is
1968 * written to the start of the log. Watch out for the header magic
1969 * number case, though.
1970 */
1971static void
1972xlog_split_iclog(
1973 struct xlog *log,
1974 void *data,
1975 uint64_t bno,
1976 unsigned int count)
1977{
1978 unsigned int split_offset = BBTOB(log->l_logBBsize - bno);
1979 unsigned int i;
1980
1981 for (i = split_offset; i < count; i += BBSIZE) {
1982 uint32_t cycle = get_unaligned_be32(data + i);
1983
1984 if (++cycle == XLOG_HEADER_MAGIC_NUM)
1985 cycle++;
1986 put_unaligned_be32(cycle, data + i);
1987 }
1988}
1989
1990static int
1991xlog_calc_iclog_size(
1992 struct xlog *log,
1993 struct xlog_in_core *iclog,
1994 uint32_t *roundoff)
1995{
1996 uint32_t count_init, count;
1997
1998 /* Add for LR header */
1999 count_init = log->l_iclog_hsize + iclog->ic_offset;
2000 count = roundup(count_init, log->l_iclog_roundoff);
2001
2002 *roundoff = count - count_init;
2003
2004 ASSERT(count >= count_init);
2005 ASSERT(*roundoff < log->l_iclog_roundoff);
2006 return count;
2007}
2008
2009/*
2010 * Flush out the in-core log (iclog) to the on-disk log in an asynchronous
2011 * fashion. Previously, we should have moved the current iclog
2012 * ptr in the log to point to the next available iclog. This allows further
2013 * write to continue while this code syncs out an iclog ready to go.
2014 * Before an in-core log can be written out, the data section must be scanned
2015 * to save away the 1st word of each BBSIZE block into the header. We replace
2016 * it with the current cycle count. Each BBSIZE block is tagged with the
2017 * cycle count because there in an implicit assumption that drives will
2018 * guarantee that entire 512 byte blocks get written at once. In other words,
2019 * we can't have part of a 512 byte block written and part not written. By
2020 * tagging each block, we will know which blocks are valid when recovering
2021 * after an unclean shutdown.
2022 *
2023 * This routine is single threaded on the iclog. No other thread can be in
2024 * this routine with the same iclog. Changing contents of iclog can there-
2025 * fore be done without grabbing the state machine lock. Updating the global
2026 * log will require grabbing the lock though.
2027 *
2028 * The entire log manager uses a logical block numbering scheme. Only
2029 * xlog_write_iclog knows about the fact that the log may not start with
2030 * block zero on a given device.
2031 */
2032STATIC void
2033xlog_sync(
2034 struct xlog *log,
2035 struct xlog_in_core *iclog,
2036 struct xlog_ticket *ticket)
2037{
2038 unsigned int count; /* byte count of bwrite */
2039 unsigned int roundoff; /* roundoff to BB or stripe */
2040 uint64_t bno;
2041 unsigned int size;
2042
2043 ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
2044 trace_xlog_iclog_sync(iclog, _RET_IP_);
2045
2046 count = xlog_calc_iclog_size(log, iclog, &roundoff);
2047
2048 /*
2049 * If we have a ticket, account for the roundoff via the ticket
2050 * reservation to avoid touching the hot grant heads needlessly.
2051 * Otherwise, we have to move grant heads directly.
2052 */
2053 if (ticket) {
2054 ticket->t_curr_res -= roundoff;
2055 } else {
2056 xlog_grant_add_space(log, &log->l_reserve_head.grant, roundoff);
2057 xlog_grant_add_space(log, &log->l_write_head.grant, roundoff);
2058 }
2059
2060 /* put cycle number in every block */
2061 xlog_pack_data(log, iclog, roundoff);
2062
2063 /* real byte length */
2064 size = iclog->ic_offset;
2065 if (xfs_has_logv2(log->l_mp))
2066 size += roundoff;
2067 iclog->ic_header.h_len = cpu_to_be32(size);
2068
2069 XFS_STATS_INC(log->l_mp, xs_log_writes);
2070 XFS_STATS_ADD(log->l_mp, xs_log_blocks, BTOBB(count));
2071
2072 bno = BLOCK_LSN(be64_to_cpu(iclog->ic_header.h_lsn));
2073
2074 /* Do we need to split this write into 2 parts? */
2075 if (bno + BTOBB(count) > log->l_logBBsize)
2076 xlog_split_iclog(log, &iclog->ic_header, bno, count);
2077
2078 /* calculcate the checksum */
2079 iclog->ic_header.h_crc = xlog_cksum(log, &iclog->ic_header,
2080 iclog->ic_datap, size);
2081 /*
2082 * Intentionally corrupt the log record CRC based on the error injection
2083 * frequency, if defined. This facilitates testing log recovery in the
2084 * event of torn writes. Hence, set the IOABORT state to abort the log
2085 * write on I/O completion and shutdown the fs. The subsequent mount
2086 * detects the bad CRC and attempts to recover.
2087 */
2088#ifdef DEBUG
2089 if (XFS_TEST_ERROR(false, log->l_mp, XFS_ERRTAG_LOG_BAD_CRC)) {
2090 iclog->ic_header.h_crc &= cpu_to_le32(0xAAAAAAAA);
2091 iclog->ic_fail_crc = true;
2092 xfs_warn(log->l_mp,
2093 "Intentionally corrupted log record at LSN 0x%llx. Shutdown imminent.",
2094 be64_to_cpu(iclog->ic_header.h_lsn));
2095 }
2096#endif
2097 xlog_verify_iclog(log, iclog, count);
2098 xlog_write_iclog(log, iclog, bno, count);
2099}
2100
2101/*
2102 * Deallocate a log structure
2103 */
2104STATIC void
2105xlog_dealloc_log(
2106 struct xlog *log)
2107{
2108 xlog_in_core_t *iclog, *next_iclog;
2109 int i;
2110
2111 /*
2112 * Destroy the CIL after waiting for iclog IO completion because an
2113 * iclog EIO error will try to shut down the log, which accesses the
2114 * CIL to wake up the waiters.
2115 */
2116 xlog_cil_destroy(log);
2117
2118 iclog = log->l_iclog;
2119 for (i = 0; i < log->l_iclog_bufs; i++) {
2120 next_iclog = iclog->ic_next;
2121 kmem_free(iclog->ic_data);
2122 kmem_free(iclog);
2123 iclog = next_iclog;
2124 }
2125
2126 log->l_mp->m_log = NULL;
2127 destroy_workqueue(log->l_ioend_workqueue);
2128 kmem_free(log);
2129}
2130
2131/*
2132 * Update counters atomically now that memcpy is done.
2133 */
2134static inline void
2135xlog_state_finish_copy(
2136 struct xlog *log,
2137 struct xlog_in_core *iclog,
2138 int record_cnt,
2139 int copy_bytes)
2140{
2141 lockdep_assert_held(&log->l_icloglock);
2142
2143 be32_add_cpu(&iclog->ic_header.h_num_logops, record_cnt);
2144 iclog->ic_offset += copy_bytes;
2145}
2146
2147/*
2148 * print out info relating to regions written which consume
2149 * the reservation
2150 */
2151void
2152xlog_print_tic_res(
2153 struct xfs_mount *mp,
2154 struct xlog_ticket *ticket)
2155{
2156 xfs_warn(mp, "ticket reservation summary:");
2157 xfs_warn(mp, " unit res = %d bytes", ticket->t_unit_res);
2158 xfs_warn(mp, " current res = %d bytes", ticket->t_curr_res);
2159 xfs_warn(mp, " original count = %d", ticket->t_ocnt);
2160 xfs_warn(mp, " remaining count = %d", ticket->t_cnt);
2161}
2162
2163/*
2164 * Print a summary of the transaction.
2165 */
2166void
2167xlog_print_trans(
2168 struct xfs_trans *tp)
2169{
2170 struct xfs_mount *mp = tp->t_mountp;
2171 struct xfs_log_item *lip;
2172
2173 /* dump core transaction and ticket info */
2174 xfs_warn(mp, "transaction summary:");
2175 xfs_warn(mp, " log res = %d", tp->t_log_res);
2176 xfs_warn(mp, " log count = %d", tp->t_log_count);
2177 xfs_warn(mp, " flags = 0x%x", tp->t_flags);
2178
2179 xlog_print_tic_res(mp, tp->t_ticket);
2180
2181 /* dump each log item */
2182 list_for_each_entry(lip, &tp->t_items, li_trans) {
2183 struct xfs_log_vec *lv = lip->li_lv;
2184 struct xfs_log_iovec *vec;
2185 int i;
2186
2187 xfs_warn(mp, "log item: ");
2188 xfs_warn(mp, " type = 0x%x", lip->li_type);
2189 xfs_warn(mp, " flags = 0x%lx", lip->li_flags);
2190 if (!lv)
2191 continue;
2192 xfs_warn(mp, " niovecs = %d", lv->lv_niovecs);
2193 xfs_warn(mp, " size = %d", lv->lv_size);
2194 xfs_warn(mp, " bytes = %d", lv->lv_bytes);
2195 xfs_warn(mp, " buf len = %d", lv->lv_buf_len);
2196
2197 /* dump each iovec for the log item */
2198 vec = lv->lv_iovecp;
2199 for (i = 0; i < lv->lv_niovecs; i++) {
2200 int dumplen = min(vec->i_len, 32);
2201
2202 xfs_warn(mp, " iovec[%d]", i);
2203 xfs_warn(mp, " type = 0x%x", vec->i_type);
2204 xfs_warn(mp, " len = %d", vec->i_len);
2205 xfs_warn(mp, " first %d bytes of iovec[%d]:", dumplen, i);
2206 xfs_hex_dump(vec->i_addr, dumplen);
2207
2208 vec++;
2209 }
2210 }
2211}
2212
2213static inline void
2214xlog_write_iovec(
2215 struct xlog_in_core *iclog,
2216 uint32_t *log_offset,
2217 void *data,
2218 uint32_t write_len,
2219 int *bytes_left,
2220 uint32_t *record_cnt,
2221 uint32_t *data_cnt)
2222{
2223 ASSERT(*log_offset < iclog->ic_log->l_iclog_size);
2224 ASSERT(*log_offset % sizeof(int32_t) == 0);
2225 ASSERT(write_len % sizeof(int32_t) == 0);
2226
2227 memcpy(iclog->ic_datap + *log_offset, data, write_len);
2228 *log_offset += write_len;
2229 *bytes_left -= write_len;
2230 (*record_cnt)++;
2231 *data_cnt += write_len;
2232}
2233
2234/*
2235 * Write log vectors into a single iclog which is guaranteed by the caller
2236 * to have enough space to write the entire log vector into.
2237 */
2238static void
2239xlog_write_full(
2240 struct xfs_log_vec *lv,
2241 struct xlog_ticket *ticket,
2242 struct xlog_in_core *iclog,
2243 uint32_t *log_offset,
2244 uint32_t *len,
2245 uint32_t *record_cnt,
2246 uint32_t *data_cnt)
2247{
2248 int index;
2249
2250 ASSERT(*log_offset + *len <= iclog->ic_size ||
2251 iclog->ic_state == XLOG_STATE_WANT_SYNC);
2252
2253 /*
2254 * Ordered log vectors have no regions to write so this
2255 * loop will naturally skip them.
2256 */
2257 for (index = 0; index < lv->lv_niovecs; index++) {
2258 struct xfs_log_iovec *reg = &lv->lv_iovecp[index];
2259 struct xlog_op_header *ophdr = reg->i_addr;
2260
2261 ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
2262 xlog_write_iovec(iclog, log_offset, reg->i_addr,
2263 reg->i_len, len, record_cnt, data_cnt);
2264 }
2265}
2266
2267static int
2268xlog_write_get_more_iclog_space(
2269 struct xlog_ticket *ticket,
2270 struct xlog_in_core **iclogp,
2271 uint32_t *log_offset,
2272 uint32_t len,
2273 uint32_t *record_cnt,
2274 uint32_t *data_cnt)
2275{
2276 struct xlog_in_core *iclog = *iclogp;
2277 struct xlog *log = iclog->ic_log;
2278 int error;
2279
2280 spin_lock(&log->l_icloglock);
2281 ASSERT(iclog->ic_state == XLOG_STATE_WANT_SYNC);
2282 xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
2283 error = xlog_state_release_iclog(log, iclog, ticket);
2284 spin_unlock(&log->l_icloglock);
2285 if (error)
2286 return error;
2287
2288 error = xlog_state_get_iclog_space(log, len, &iclog, ticket,
2289 log_offset);
2290 if (error)
2291 return error;
2292 *record_cnt = 0;
2293 *data_cnt = 0;
2294 *iclogp = iclog;
2295 return 0;
2296}
2297
2298/*
2299 * Write log vectors into a single iclog which is smaller than the current chain
2300 * length. We write until we cannot fit a full record into the remaining space
2301 * and then stop. We return the log vector that is to be written that cannot
2302 * wholly fit in the iclog.
2303 */
2304static int
2305xlog_write_partial(
2306 struct xfs_log_vec *lv,
2307 struct xlog_ticket *ticket,
2308 struct xlog_in_core **iclogp,
2309 uint32_t *log_offset,
2310 uint32_t *len,
2311 uint32_t *record_cnt,
2312 uint32_t *data_cnt)
2313{
2314 struct xlog_in_core *iclog = *iclogp;
2315 struct xlog_op_header *ophdr;
2316 int index = 0;
2317 uint32_t rlen;
2318 int error;
2319
2320 /* walk the logvec, copying until we run out of space in the iclog */
2321 for (index = 0; index < lv->lv_niovecs; index++) {
2322 struct xfs_log_iovec *reg = &lv->lv_iovecp[index];
2323 uint32_t reg_offset = 0;
2324
2325 /*
2326 * The first region of a continuation must have a non-zero
2327 * length otherwise log recovery will just skip over it and
2328 * start recovering from the next opheader it finds. Because we
2329 * mark the next opheader as a continuation, recovery will then
2330 * incorrectly add the continuation to the previous region and
2331 * that breaks stuff.
2332 *
2333 * Hence if there isn't space for region data after the
2334 * opheader, then we need to start afresh with a new iclog.
2335 */
2336 if (iclog->ic_size - *log_offset <=
2337 sizeof(struct xlog_op_header)) {
2338 error = xlog_write_get_more_iclog_space(ticket,
2339 &iclog, log_offset, *len, record_cnt,
2340 data_cnt);
2341 if (error)
2342 return error;
2343 }
2344
2345 ophdr = reg->i_addr;
2346 rlen = min_t(uint32_t, reg->i_len, iclog->ic_size - *log_offset);
2347
2348 ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
2349 ophdr->oh_len = cpu_to_be32(rlen - sizeof(struct xlog_op_header));
2350 if (rlen != reg->i_len)
2351 ophdr->oh_flags |= XLOG_CONTINUE_TRANS;
2352
2353 xlog_write_iovec(iclog, log_offset, reg->i_addr,
2354 rlen, len, record_cnt, data_cnt);
2355
2356 /* If we wrote the whole region, move to the next. */
2357 if (rlen == reg->i_len)
2358 continue;
2359
2360 /*
2361 * We now have a partially written iovec, but it can span
2362 * multiple iclogs so we loop here. First we release the iclog
2363 * we currently have, then we get a new iclog and add a new
2364 * opheader. Then we continue copying from where we were until
2365 * we either complete the iovec or fill the iclog. If we
2366 * complete the iovec, then we increment the index and go right
2367 * back to the top of the outer loop. if we fill the iclog, we
2368 * run the inner loop again.
2369 *
2370 * This is complicated by the tail of a region using all the
2371 * space in an iclog and hence requiring us to release the iclog
2372 * and get a new one before returning to the outer loop. We must
2373 * always guarantee that we exit this inner loop with at least
2374 * space for log transaction opheaders left in the current
2375 * iclog, hence we cannot just terminate the loop at the end
2376 * of the of the continuation. So we loop while there is no
2377 * space left in the current iclog, and check for the end of the
2378 * continuation after getting a new iclog.
2379 */
2380 do {
2381 /*
2382 * Ensure we include the continuation opheader in the
2383 * space we need in the new iclog by adding that size
2384 * to the length we require. This continuation opheader
2385 * needs to be accounted to the ticket as the space it
2386 * consumes hasn't been accounted to the lv we are
2387 * writing.
2388 */
2389 error = xlog_write_get_more_iclog_space(ticket,
2390 &iclog, log_offset,
2391 *len + sizeof(struct xlog_op_header),
2392 record_cnt, data_cnt);
2393 if (error)
2394 return error;
2395
2396 ophdr = iclog->ic_datap + *log_offset;
2397 ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
2398 ophdr->oh_clientid = XFS_TRANSACTION;
2399 ophdr->oh_res2 = 0;
2400 ophdr->oh_flags = XLOG_WAS_CONT_TRANS;
2401
2402 ticket->t_curr_res -= sizeof(struct xlog_op_header);
2403 *log_offset += sizeof(struct xlog_op_header);
2404 *data_cnt += sizeof(struct xlog_op_header);
2405
2406 /*
2407 * If rlen fits in the iclog, then end the region
2408 * continuation. Otherwise we're going around again.
2409 */
2410 reg_offset += rlen;
2411 rlen = reg->i_len - reg_offset;
2412 if (rlen <= iclog->ic_size - *log_offset)
2413 ophdr->oh_flags |= XLOG_END_TRANS;
2414 else
2415 ophdr->oh_flags |= XLOG_CONTINUE_TRANS;
2416
2417 rlen = min_t(uint32_t, rlen, iclog->ic_size - *log_offset);
2418 ophdr->oh_len = cpu_to_be32(rlen);
2419
2420 xlog_write_iovec(iclog, log_offset,
2421 reg->i_addr + reg_offset,
2422 rlen, len, record_cnt, data_cnt);
2423
2424 } while (ophdr->oh_flags & XLOG_CONTINUE_TRANS);
2425 }
2426
2427 /*
2428 * No more iovecs remain in this logvec so return the next log vec to
2429 * the caller so it can go back to fast path copying.
2430 */
2431 *iclogp = iclog;
2432 return 0;
2433}
2434
2435/*
2436 * Write some region out to in-core log
2437 *
2438 * This will be called when writing externally provided regions or when
2439 * writing out a commit record for a given transaction.
2440 *
2441 * General algorithm:
2442 * 1. Find total length of this write. This may include adding to the
2443 * lengths passed in.
2444 * 2. Check whether we violate the tickets reservation.
2445 * 3. While writing to this iclog
2446 * A. Reserve as much space in this iclog as can get
2447 * B. If this is first write, save away start lsn
2448 * C. While writing this region:
2449 * 1. If first write of transaction, write start record
2450 * 2. Write log operation header (header per region)
2451 * 3. Find out if we can fit entire region into this iclog
2452 * 4. Potentially, verify destination memcpy ptr
2453 * 5. Memcpy (partial) region
2454 * 6. If partial copy, release iclog; otherwise, continue
2455 * copying more regions into current iclog
2456 * 4. Mark want sync bit (in simulation mode)
2457 * 5. Release iclog for potential flush to on-disk log.
2458 *
2459 * ERRORS:
2460 * 1. Panic if reservation is overrun. This should never happen since
2461 * reservation amounts are generated internal to the filesystem.
2462 * NOTES:
2463 * 1. Tickets are single threaded data structures.
2464 * 2. The XLOG_END_TRANS & XLOG_CONTINUE_TRANS flags are passed down to the
2465 * syncing routine. When a single log_write region needs to span
2466 * multiple in-core logs, the XLOG_CONTINUE_TRANS bit should be set
2467 * on all log operation writes which don't contain the end of the
2468 * region. The XLOG_END_TRANS bit is used for the in-core log
2469 * operation which contains the end of the continued log_write region.
2470 * 3. When xlog_state_get_iclog_space() grabs the rest of the current iclog,
2471 * we don't really know exactly how much space will be used. As a result,
2472 * we don't update ic_offset until the end when we know exactly how many
2473 * bytes have been written out.
2474 */
2475int
2476xlog_write(
2477 struct xlog *log,
2478 struct xfs_cil_ctx *ctx,
2479 struct list_head *lv_chain,
2480 struct xlog_ticket *ticket,
2481 uint32_t len)
2482
2483{
2484 struct xlog_in_core *iclog = NULL;
2485 struct xfs_log_vec *lv;
2486 uint32_t record_cnt = 0;
2487 uint32_t data_cnt = 0;
2488 int error = 0;
2489 int log_offset;
2490
2491 if (ticket->t_curr_res < 0) {
2492 xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
2493 "ctx ticket reservation ran out. Need to up reservation");
2494 xlog_print_tic_res(log->l_mp, ticket);
2495 xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
2496 }
2497
2498 error = xlog_state_get_iclog_space(log, len, &iclog, ticket,
2499 &log_offset);
2500 if (error)
2501 return error;
2502
2503 ASSERT(log_offset <= iclog->ic_size - 1);
2504
2505 /*
2506 * If we have a context pointer, pass it the first iclog we are
2507 * writing to so it can record state needed for iclog write
2508 * ordering.
2509 */
2510 if (ctx)
2511 xlog_cil_set_ctx_write_state(ctx, iclog);
2512
2513 list_for_each_entry(lv, lv_chain, lv_list) {
2514 /*
2515 * If the entire log vec does not fit in the iclog, punt it to
2516 * the partial copy loop which can handle this case.
2517 */
2518 if (lv->lv_niovecs &&
2519 lv->lv_bytes > iclog->ic_size - log_offset) {
2520 error = xlog_write_partial(lv, ticket, &iclog,
2521 &log_offset, &len, &record_cnt,
2522 &data_cnt);
2523 if (error) {
2524 /*
2525 * We have no iclog to release, so just return
2526 * the error immediately.
2527 */
2528 return error;
2529 }
2530 } else {
2531 xlog_write_full(lv, ticket, iclog, &log_offset,
2532 &len, &record_cnt, &data_cnt);
2533 }
2534 }
2535 ASSERT(len == 0);
2536
2537 /*
2538 * We've already been guaranteed that the last writes will fit inside
2539 * the current iclog, and hence it will already have the space used by
2540 * those writes accounted to it. Hence we do not need to update the
2541 * iclog with the number of bytes written here.
2542 */
2543 spin_lock(&log->l_icloglock);
2544 xlog_state_finish_copy(log, iclog, record_cnt, 0);
2545 error = xlog_state_release_iclog(log, iclog, ticket);
2546 spin_unlock(&log->l_icloglock);
2547
2548 return error;
2549}
2550
2551static void
2552xlog_state_activate_iclog(
2553 struct xlog_in_core *iclog,
2554 int *iclogs_changed)
2555{
2556 ASSERT(list_empty_careful(&iclog->ic_callbacks));
2557 trace_xlog_iclog_activate(iclog, _RET_IP_);
2558
2559 /*
2560 * If the number of ops in this iclog indicate it just contains the
2561 * dummy transaction, we can change state into IDLE (the second time
2562 * around). Otherwise we should change the state into NEED a dummy.
2563 * We don't need to cover the dummy.
2564 */
2565 if (*iclogs_changed == 0 &&
2566 iclog->ic_header.h_num_logops == cpu_to_be32(XLOG_COVER_OPS)) {
2567 *iclogs_changed = 1;
2568 } else {
2569 /*
2570 * We have two dirty iclogs so start over. This could also be
2571 * num of ops indicating this is not the dummy going out.
2572 */
2573 *iclogs_changed = 2;
2574 }
2575
2576 iclog->ic_state = XLOG_STATE_ACTIVE;
2577 iclog->ic_offset = 0;
2578 iclog->ic_header.h_num_logops = 0;
2579 memset(iclog->ic_header.h_cycle_data, 0,
2580 sizeof(iclog->ic_header.h_cycle_data));
2581 iclog->ic_header.h_lsn = 0;
2582 iclog->ic_header.h_tail_lsn = 0;
2583}
2584
2585/*
2586 * Loop through all iclogs and mark all iclogs currently marked DIRTY as
2587 * ACTIVE after iclog I/O has completed.
2588 */
2589static void
2590xlog_state_activate_iclogs(
2591 struct xlog *log,
2592 int *iclogs_changed)
2593{
2594 struct xlog_in_core *iclog = log->l_iclog;
2595
2596 do {
2597 if (iclog->ic_state == XLOG_STATE_DIRTY)
2598 xlog_state_activate_iclog(iclog, iclogs_changed);
2599 /*
2600 * The ordering of marking iclogs ACTIVE must be maintained, so
2601 * an iclog doesn't become ACTIVE beyond one that is SYNCING.
2602 */
2603 else if (iclog->ic_state != XLOG_STATE_ACTIVE)
2604 break;
2605 } while ((iclog = iclog->ic_next) != log->l_iclog);
2606}
2607
2608static int
2609xlog_covered_state(
2610 int prev_state,
2611 int iclogs_changed)
2612{
2613 /*
2614 * We go to NEED for any non-covering writes. We go to NEED2 if we just
2615 * wrote the first covering record (DONE). We go to IDLE if we just
2616 * wrote the second covering record (DONE2) and remain in IDLE until a
2617 * non-covering write occurs.
2618 */
2619 switch (prev_state) {
2620 case XLOG_STATE_COVER_IDLE:
2621 if (iclogs_changed == 1)
2622 return XLOG_STATE_COVER_IDLE;
2623 fallthrough;
2624 case XLOG_STATE_COVER_NEED:
2625 case XLOG_STATE_COVER_NEED2:
2626 break;
2627 case XLOG_STATE_COVER_DONE:
2628 if (iclogs_changed == 1)
2629 return XLOG_STATE_COVER_NEED2;
2630 break;
2631 case XLOG_STATE_COVER_DONE2:
2632 if (iclogs_changed == 1)
2633 return XLOG_STATE_COVER_IDLE;
2634 break;
2635 default:
2636 ASSERT(0);
2637 }
2638
2639 return XLOG_STATE_COVER_NEED;
2640}
2641
2642STATIC void
2643xlog_state_clean_iclog(
2644 struct xlog *log,
2645 struct xlog_in_core *dirty_iclog)
2646{
2647 int iclogs_changed = 0;
2648
2649 trace_xlog_iclog_clean(dirty_iclog, _RET_IP_);
2650
2651 dirty_iclog->ic_state = XLOG_STATE_DIRTY;
2652
2653 xlog_state_activate_iclogs(log, &iclogs_changed);
2654 wake_up_all(&dirty_iclog->ic_force_wait);
2655
2656 if (iclogs_changed) {
2657 log->l_covered_state = xlog_covered_state(log->l_covered_state,
2658 iclogs_changed);
2659 }
2660}
2661
2662STATIC xfs_lsn_t
2663xlog_get_lowest_lsn(
2664 struct xlog *log)
2665{
2666 struct xlog_in_core *iclog = log->l_iclog;
2667 xfs_lsn_t lowest_lsn = 0, lsn;
2668
2669 do {
2670 if (iclog->ic_state == XLOG_STATE_ACTIVE ||
2671 iclog->ic_state == XLOG_STATE_DIRTY)
2672 continue;
2673
2674 lsn = be64_to_cpu(iclog->ic_header.h_lsn);
2675 if ((lsn && !lowest_lsn) || XFS_LSN_CMP(lsn, lowest_lsn) < 0)
2676 lowest_lsn = lsn;
2677 } while ((iclog = iclog->ic_next) != log->l_iclog);
2678
2679 return lowest_lsn;
2680}
2681
2682/*
2683 * Completion of a iclog IO does not imply that a transaction has completed, as
2684 * transactions can be large enough to span many iclogs. We cannot change the
2685 * tail of the log half way through a transaction as this may be the only
2686 * transaction in the log and moving the tail to point to the middle of it
2687 * will prevent recovery from finding the start of the transaction. Hence we
2688 * should only update the last_sync_lsn if this iclog contains transaction
2689 * completion callbacks on it.
2690 *
2691 * We have to do this before we drop the icloglock to ensure we are the only one
2692 * that can update it.
2693 *
2694 * If we are moving the last_sync_lsn forwards, we also need to ensure we kick
2695 * the reservation grant head pushing. This is due to the fact that the push
2696 * target is bound by the current last_sync_lsn value. Hence if we have a large
2697 * amount of log space bound up in this committing transaction then the
2698 * last_sync_lsn value may be the limiting factor preventing tail pushing from
2699 * freeing space in the log. Hence once we've updated the last_sync_lsn we
2700 * should push the AIL to ensure the push target (and hence the grant head) is
2701 * no longer bound by the old log head location and can move forwards and make
2702 * progress again.
2703 */
2704static void
2705xlog_state_set_callback(
2706 struct xlog *log,
2707 struct xlog_in_core *iclog,
2708 xfs_lsn_t header_lsn)
2709{
2710 trace_xlog_iclog_callback(iclog, _RET_IP_);
2711 iclog->ic_state = XLOG_STATE_CALLBACK;
2712
2713 ASSERT(XFS_LSN_CMP(atomic64_read(&log->l_last_sync_lsn),
2714 header_lsn) <= 0);
2715
2716 if (list_empty_careful(&iclog->ic_callbacks))
2717 return;
2718
2719 atomic64_set(&log->l_last_sync_lsn, header_lsn);
2720 xlog_grant_push_ail(log, 0);
2721}
2722
2723/*
2724 * Return true if we need to stop processing, false to continue to the next
2725 * iclog. The caller will need to run callbacks if the iclog is returned in the
2726 * XLOG_STATE_CALLBACK state.
2727 */
2728static bool
2729xlog_state_iodone_process_iclog(
2730 struct xlog *log,
2731 struct xlog_in_core *iclog)
2732{
2733 xfs_lsn_t lowest_lsn;
2734 xfs_lsn_t header_lsn;
2735
2736 switch (iclog->ic_state) {
2737 case XLOG_STATE_ACTIVE:
2738 case XLOG_STATE_DIRTY:
2739 /*
2740 * Skip all iclogs in the ACTIVE & DIRTY states:
2741 */
2742 return false;
2743 case XLOG_STATE_DONE_SYNC:
2744 /*
2745 * Now that we have an iclog that is in the DONE_SYNC state, do
2746 * one more check here to see if we have chased our tail around.
2747 * If this is not the lowest lsn iclog, then we will leave it
2748 * for another completion to process.
2749 */
2750 header_lsn = be64_to_cpu(iclog->ic_header.h_lsn);
2751 lowest_lsn = xlog_get_lowest_lsn(log);
2752 if (lowest_lsn && XFS_LSN_CMP(lowest_lsn, header_lsn) < 0)
2753 return false;
2754 xlog_state_set_callback(log, iclog, header_lsn);
2755 return false;
2756 default:
2757 /*
2758 * Can only perform callbacks in order. Since this iclog is not
2759 * in the DONE_SYNC state, we skip the rest and just try to
2760 * clean up.
2761 */
2762 return true;
2763 }
2764}
2765
2766/*
2767 * Loop over all the iclogs, running attached callbacks on them. Return true if
2768 * we ran any callbacks, indicating that we dropped the icloglock. We don't need
2769 * to handle transient shutdown state here at all because
2770 * xlog_state_shutdown_callbacks() will be run to do the necessary shutdown
2771 * cleanup of the callbacks.
2772 */
2773static bool
2774xlog_state_do_iclog_callbacks(
2775 struct xlog *log)
2776 __releases(&log->l_icloglock)
2777 __acquires(&log->l_icloglock)
2778{
2779 struct xlog_in_core *first_iclog = log->l_iclog;
2780 struct xlog_in_core *iclog = first_iclog;
2781 bool ran_callback = false;
2782
2783 do {
2784 LIST_HEAD(cb_list);
2785
2786 if (xlog_state_iodone_process_iclog(log, iclog))
2787 break;
2788 if (iclog->ic_state != XLOG_STATE_CALLBACK) {
2789 iclog = iclog->ic_next;
2790 continue;
2791 }
2792 list_splice_init(&iclog->ic_callbacks, &cb_list);
2793 spin_unlock(&log->l_icloglock);
2794
2795 trace_xlog_iclog_callbacks_start(iclog, _RET_IP_);
2796 xlog_cil_process_committed(&cb_list);
2797 trace_xlog_iclog_callbacks_done(iclog, _RET_IP_);
2798 ran_callback = true;
2799
2800 spin_lock(&log->l_icloglock);
2801 xlog_state_clean_iclog(log, iclog);
2802 iclog = iclog->ic_next;
2803 } while (iclog != first_iclog);
2804
2805 return ran_callback;
2806}
2807
2808
2809/*
2810 * Loop running iclog completion callbacks until there are no more iclogs in a
2811 * state that can run callbacks.
2812 */
2813STATIC void
2814xlog_state_do_callback(
2815 struct xlog *log)
2816{
2817 int flushcnt = 0;
2818 int repeats = 0;
2819
2820 spin_lock(&log->l_icloglock);
2821 while (xlog_state_do_iclog_callbacks(log)) {
2822 if (xlog_is_shutdown(log))
2823 break;
2824
2825 if (++repeats > 5000) {
2826 flushcnt += repeats;
2827 repeats = 0;
2828 xfs_warn(log->l_mp,
2829 "%s: possible infinite loop (%d iterations)",
2830 __func__, flushcnt);
2831 }
2832 }
2833
2834 if (log->l_iclog->ic_state == XLOG_STATE_ACTIVE)
2835 wake_up_all(&log->l_flush_wait);
2836
2837 spin_unlock(&log->l_icloglock);
2838}
2839
2840
2841/*
2842 * Finish transitioning this iclog to the dirty state.
2843 *
2844 * Callbacks could take time, so they are done outside the scope of the
2845 * global state machine log lock.
2846 */
2847STATIC void
2848xlog_state_done_syncing(
2849 struct xlog_in_core *iclog)
2850{
2851 struct xlog *log = iclog->ic_log;
2852
2853 spin_lock(&log->l_icloglock);
2854 ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
2855 trace_xlog_iclog_sync_done(iclog, _RET_IP_);
2856
2857 /*
2858 * If we got an error, either on the first buffer, or in the case of
2859 * split log writes, on the second, we shut down the file system and
2860 * no iclogs should ever be attempted to be written to disk again.
2861 */
2862 if (!xlog_is_shutdown(log)) {
2863 ASSERT(iclog->ic_state == XLOG_STATE_SYNCING);
2864 iclog->ic_state = XLOG_STATE_DONE_SYNC;
2865 }
2866
2867 /*
2868 * Someone could be sleeping prior to writing out the next
2869 * iclog buffer, we wake them all, one will get to do the
2870 * I/O, the others get to wait for the result.
2871 */
2872 wake_up_all(&iclog->ic_write_wait);
2873 spin_unlock(&log->l_icloglock);
2874 xlog_state_do_callback(log);
2875}
2876
2877/*
2878 * If the head of the in-core log ring is not (ACTIVE or DIRTY), then we must
2879 * sleep. We wait on the flush queue on the head iclog as that should be
2880 * the first iclog to complete flushing. Hence if all iclogs are syncing,
2881 * we will wait here and all new writes will sleep until a sync completes.
2882 *
2883 * The in-core logs are used in a circular fashion. They are not used
2884 * out-of-order even when an iclog past the head is free.
2885 *
2886 * return:
2887 * * log_offset where xlog_write() can start writing into the in-core
2888 * log's data space.
2889 * * in-core log pointer to which xlog_write() should write.
2890 * * boolean indicating this is a continued write to an in-core log.
2891 * If this is the last write, then the in-core log's offset field
2892 * needs to be incremented, depending on the amount of data which
2893 * is copied.
2894 */
2895STATIC int
2896xlog_state_get_iclog_space(
2897 struct xlog *log,
2898 int len,
2899 struct xlog_in_core **iclogp,
2900 struct xlog_ticket *ticket,
2901 int *logoffsetp)
2902{
2903 int log_offset;
2904 xlog_rec_header_t *head;
2905 xlog_in_core_t *iclog;
2906
2907restart:
2908 spin_lock(&log->l_icloglock);
2909 if (xlog_is_shutdown(log)) {
2910 spin_unlock(&log->l_icloglock);
2911 return -EIO;
2912 }
2913
2914 iclog = log->l_iclog;
2915 if (iclog->ic_state != XLOG_STATE_ACTIVE) {
2916 XFS_STATS_INC(log->l_mp, xs_log_noiclogs);
2917
2918 /* Wait for log writes to have flushed */
2919 xlog_wait(&log->l_flush_wait, &log->l_icloglock);
2920 goto restart;
2921 }
2922
2923 head = &iclog->ic_header;
2924
2925 atomic_inc(&iclog->ic_refcnt); /* prevents sync */
2926 log_offset = iclog->ic_offset;
2927
2928 trace_xlog_iclog_get_space(iclog, _RET_IP_);
2929
2930 /* On the 1st write to an iclog, figure out lsn. This works
2931 * if iclogs marked XLOG_STATE_WANT_SYNC always write out what they are
2932 * committing to. If the offset is set, that's how many blocks
2933 * must be written.
2934 */
2935 if (log_offset == 0) {
2936 ticket->t_curr_res -= log->l_iclog_hsize;
2937 head->h_cycle = cpu_to_be32(log->l_curr_cycle);
2938 head->h_lsn = cpu_to_be64(
2939 xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block));
2940 ASSERT(log->l_curr_block >= 0);
2941 }
2942
2943 /* If there is enough room to write everything, then do it. Otherwise,
2944 * claim the rest of the region and make sure the XLOG_STATE_WANT_SYNC
2945 * bit is on, so this will get flushed out. Don't update ic_offset
2946 * until you know exactly how many bytes get copied. Therefore, wait
2947 * until later to update ic_offset.
2948 *
2949 * xlog_write() algorithm assumes that at least 2 xlog_op_header_t's
2950 * can fit into remaining data section.
2951 */
2952 if (iclog->ic_size - iclog->ic_offset < 2*sizeof(xlog_op_header_t)) {
2953 int error = 0;
2954
2955 xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
2956
2957 /*
2958 * If we are the only one writing to this iclog, sync it to
2959 * disk. We need to do an atomic compare and decrement here to
2960 * avoid racing with concurrent atomic_dec_and_lock() calls in
2961 * xlog_state_release_iclog() when there is more than one
2962 * reference to the iclog.
2963 */
2964 if (!atomic_add_unless(&iclog->ic_refcnt, -1, 1))
2965 error = xlog_state_release_iclog(log, iclog, ticket);
2966 spin_unlock(&log->l_icloglock);
2967 if (error)
2968 return error;
2969 goto restart;
2970 }
2971
2972 /* Do we have enough room to write the full amount in the remainder
2973 * of this iclog? Or must we continue a write on the next iclog and
2974 * mark this iclog as completely taken? In the case where we switch
2975 * iclogs (to mark it taken), this particular iclog will release/sync
2976 * to disk in xlog_write().
2977 */
2978 if (len <= iclog->ic_size - iclog->ic_offset)
2979 iclog->ic_offset += len;
2980 else
2981 xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
2982 *iclogp = iclog;
2983
2984 ASSERT(iclog->ic_offset <= iclog->ic_size);
2985 spin_unlock(&log->l_icloglock);
2986
2987 *logoffsetp = log_offset;
2988 return 0;
2989}
2990
2991/*
2992 * The first cnt-1 times a ticket goes through here we don't need to move the
2993 * grant write head because the permanent reservation has reserved cnt times the
2994 * unit amount. Release part of current permanent unit reservation and reset
2995 * current reservation to be one units worth. Also move grant reservation head
2996 * forward.
2997 */
2998void
2999xfs_log_ticket_regrant(
3000 struct xlog *log,
3001 struct xlog_ticket *ticket)
3002{
3003 trace_xfs_log_ticket_regrant(log, ticket);
3004
3005 if (ticket->t_cnt > 0)
3006 ticket->t_cnt--;
3007
3008 xlog_grant_sub_space(log, &log->l_reserve_head.grant,
3009 ticket->t_curr_res);
3010 xlog_grant_sub_space(log, &log->l_write_head.grant,
3011 ticket->t_curr_res);
3012 ticket->t_curr_res = ticket->t_unit_res;
3013
3014 trace_xfs_log_ticket_regrant_sub(log, ticket);
3015
3016 /* just return if we still have some of the pre-reserved space */
3017 if (!ticket->t_cnt) {
3018 xlog_grant_add_space(log, &log->l_reserve_head.grant,
3019 ticket->t_unit_res);
3020 trace_xfs_log_ticket_regrant_exit(log, ticket);
3021
3022 ticket->t_curr_res = ticket->t_unit_res;
3023 }
3024
3025 xfs_log_ticket_put(ticket);
3026}
3027
3028/*
3029 * Give back the space left from a reservation.
3030 *
3031 * All the information we need to make a correct determination of space left
3032 * is present. For non-permanent reservations, things are quite easy. The
3033 * count should have been decremented to zero. We only need to deal with the
3034 * space remaining in the current reservation part of the ticket. If the
3035 * ticket contains a permanent reservation, there may be left over space which
3036 * needs to be released. A count of N means that N-1 refills of the current
3037 * reservation can be done before we need to ask for more space. The first
3038 * one goes to fill up the first current reservation. Once we run out of
3039 * space, the count will stay at zero and the only space remaining will be
3040 * in the current reservation field.
3041 */
3042void
3043xfs_log_ticket_ungrant(
3044 struct xlog *log,
3045 struct xlog_ticket *ticket)
3046{
3047 int bytes;
3048
3049 trace_xfs_log_ticket_ungrant(log, ticket);
3050
3051 if (ticket->t_cnt > 0)
3052 ticket->t_cnt--;
3053
3054 trace_xfs_log_ticket_ungrant_sub(log, ticket);
3055
3056 /*
3057 * If this is a permanent reservation ticket, we may be able to free
3058 * up more space based on the remaining count.
3059 */
3060 bytes = ticket->t_curr_res;
3061 if (ticket->t_cnt > 0) {
3062 ASSERT(ticket->t_flags & XLOG_TIC_PERM_RESERV);
3063 bytes += ticket->t_unit_res*ticket->t_cnt;
3064 }
3065
3066 xlog_grant_sub_space(log, &log->l_reserve_head.grant, bytes);
3067 xlog_grant_sub_space(log, &log->l_write_head.grant, bytes);
3068
3069 trace_xfs_log_ticket_ungrant_exit(log, ticket);
3070
3071 xfs_log_space_wake(log->l_mp);
3072 xfs_log_ticket_put(ticket);
3073}
3074
3075/*
3076 * This routine will mark the current iclog in the ring as WANT_SYNC and move
3077 * the current iclog pointer to the next iclog in the ring.
3078 */
3079void
3080xlog_state_switch_iclogs(
3081 struct xlog *log,
3082 struct xlog_in_core *iclog,
3083 int eventual_size)
3084{
3085 ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE);
3086 assert_spin_locked(&log->l_icloglock);
3087 trace_xlog_iclog_switch(iclog, _RET_IP_);
3088
3089 if (!eventual_size)
3090 eventual_size = iclog->ic_offset;
3091 iclog->ic_state = XLOG_STATE_WANT_SYNC;
3092 iclog->ic_header.h_prev_block = cpu_to_be32(log->l_prev_block);
3093 log->l_prev_block = log->l_curr_block;
3094 log->l_prev_cycle = log->l_curr_cycle;
3095
3096 /* roll log?: ic_offset changed later */
3097 log->l_curr_block += BTOBB(eventual_size)+BTOBB(log->l_iclog_hsize);
3098
3099 /* Round up to next log-sunit */
3100 if (log->l_iclog_roundoff > BBSIZE) {
3101 uint32_t sunit_bb = BTOBB(log->l_iclog_roundoff);
3102 log->l_curr_block = roundup(log->l_curr_block, sunit_bb);
3103 }
3104
3105 if (log->l_curr_block >= log->l_logBBsize) {
3106 /*
3107 * Rewind the current block before the cycle is bumped to make
3108 * sure that the combined LSN never transiently moves forward
3109 * when the log wraps to the next cycle. This is to support the
3110 * unlocked sample of these fields from xlog_valid_lsn(). Most
3111 * other cases should acquire l_icloglock.
3112 */
3113 log->l_curr_block -= log->l_logBBsize;
3114 ASSERT(log->l_curr_block >= 0);
3115 smp_wmb();
3116 log->l_curr_cycle++;
3117 if (log->l_curr_cycle == XLOG_HEADER_MAGIC_NUM)
3118 log->l_curr_cycle++;
3119 }
3120 ASSERT(iclog == log->l_iclog);
3121 log->l_iclog = iclog->ic_next;
3122}
3123
3124/*
3125 * Force the iclog to disk and check if the iclog has been completed before
3126 * xlog_force_iclog() returns. This can happen on synchronous (e.g.
3127 * pmem) or fast async storage because we drop the icloglock to issue the IO.
3128 * If completion has already occurred, tell the caller so that it can avoid an
3129 * unnecessary wait on the iclog.
3130 */
3131static int
3132xlog_force_and_check_iclog(
3133 struct xlog_in_core *iclog,
3134 bool *completed)
3135{
3136 xfs_lsn_t lsn = be64_to_cpu(iclog->ic_header.h_lsn);
3137 int error;
3138
3139 *completed = false;
3140 error = xlog_force_iclog(iclog);
3141 if (error)
3142 return error;
3143
3144 /*
3145 * If the iclog has already been completed and reused the header LSN
3146 * will have been rewritten by completion
3147 */
3148 if (be64_to_cpu(iclog->ic_header.h_lsn) != lsn)
3149 *completed = true;
3150 return 0;
3151}
3152
3153/*
3154 * Write out all data in the in-core log as of this exact moment in time.
3155 *
3156 * Data may be written to the in-core log during this call. However,
3157 * we don't guarantee this data will be written out. A change from past
3158 * implementation means this routine will *not* write out zero length LRs.
3159 *
3160 * Basically, we try and perform an intelligent scan of the in-core logs.
3161 * If we determine there is no flushable data, we just return. There is no
3162 * flushable data if:
3163 *
3164 * 1. the current iclog is active and has no data; the previous iclog
3165 * is in the active or dirty state.
3166 * 2. the current iclog is drity, and the previous iclog is in the
3167 * active or dirty state.
3168 *
3169 * We may sleep if:
3170 *
3171 * 1. the current iclog is not in the active nor dirty state.
3172 * 2. the current iclog dirty, and the previous iclog is not in the
3173 * active nor dirty state.
3174 * 3. the current iclog is active, and there is another thread writing
3175 * to this particular iclog.
3176 * 4. a) the current iclog is active and has no other writers
3177 * b) when we return from flushing out this iclog, it is still
3178 * not in the active nor dirty state.
3179 */
3180int
3181xfs_log_force(
3182 struct xfs_mount *mp,
3183 uint flags)
3184{
3185 struct xlog *log = mp->m_log;
3186 struct xlog_in_core *iclog;
3187
3188 XFS_STATS_INC(mp, xs_log_force);
3189 trace_xfs_log_force(mp, 0, _RET_IP_);
3190
3191 xlog_cil_force(log);
3192
3193 spin_lock(&log->l_icloglock);
3194 if (xlog_is_shutdown(log))
3195 goto out_error;
3196
3197 iclog = log->l_iclog;
3198 trace_xlog_iclog_force(iclog, _RET_IP_);
3199
3200 if (iclog->ic_state == XLOG_STATE_DIRTY ||
3201 (iclog->ic_state == XLOG_STATE_ACTIVE &&
3202 atomic_read(&iclog->ic_refcnt) == 0 && iclog->ic_offset == 0)) {
3203 /*
3204 * If the head is dirty or (active and empty), then we need to
3205 * look at the previous iclog.
3206 *
3207 * If the previous iclog is active or dirty we are done. There
3208 * is nothing to sync out. Otherwise, we attach ourselves to the
3209 * previous iclog and go to sleep.
3210 */
3211 iclog = iclog->ic_prev;
3212 } else if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3213 if (atomic_read(&iclog->ic_refcnt) == 0) {
3214 /* We have exclusive access to this iclog. */
3215 bool completed;
3216
3217 if (xlog_force_and_check_iclog(iclog, &completed))
3218 goto out_error;
3219
3220 if (completed)
3221 goto out_unlock;
3222 } else {
3223 /*
3224 * Someone else is still writing to this iclog, so we
3225 * need to ensure that when they release the iclog it
3226 * gets synced immediately as we may be waiting on it.
3227 */
3228 xlog_state_switch_iclogs(log, iclog, 0);
3229 }
3230 }
3231
3232 /*
3233 * The iclog we are about to wait on may contain the checkpoint pushed
3234 * by the above xlog_cil_force() call, but it may not have been pushed
3235 * to disk yet. Like the ACTIVE case above, we need to make sure caches
3236 * are flushed when this iclog is written.
3237 */
3238 if (iclog->ic_state == XLOG_STATE_WANT_SYNC)
3239 iclog->ic_flags |= XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA;
3240
3241 if (flags & XFS_LOG_SYNC)
3242 return xlog_wait_on_iclog(iclog);
3243out_unlock:
3244 spin_unlock(&log->l_icloglock);
3245 return 0;
3246out_error:
3247 spin_unlock(&log->l_icloglock);
3248 return -EIO;
3249}
3250
3251/*
3252 * Force the log to a specific LSN.
3253 *
3254 * If an iclog with that lsn can be found:
3255 * If it is in the DIRTY state, just return.
3256 * If it is in the ACTIVE state, move the in-core log into the WANT_SYNC
3257 * state and go to sleep or return.
3258 * If it is in any other state, go to sleep or return.
3259 *
3260 * Synchronous forces are implemented with a wait queue. All callers trying
3261 * to force a given lsn to disk must wait on the queue attached to the
3262 * specific in-core log. When given in-core log finally completes its write
3263 * to disk, that thread will wake up all threads waiting on the queue.
3264 */
3265static int
3266xlog_force_lsn(
3267 struct xlog *log,
3268 xfs_lsn_t lsn,
3269 uint flags,
3270 int *log_flushed,
3271 bool already_slept)
3272{
3273 struct xlog_in_core *iclog;
3274 bool completed;
3275
3276 spin_lock(&log->l_icloglock);
3277 if (xlog_is_shutdown(log))
3278 goto out_error;
3279
3280 iclog = log->l_iclog;
3281 while (be64_to_cpu(iclog->ic_header.h_lsn) != lsn) {
3282 trace_xlog_iclog_force_lsn(iclog, _RET_IP_);
3283 iclog = iclog->ic_next;
3284 if (iclog == log->l_iclog)
3285 goto out_unlock;
3286 }
3287
3288 switch (iclog->ic_state) {
3289 case XLOG_STATE_ACTIVE:
3290 /*
3291 * We sleep here if we haven't already slept (e.g. this is the
3292 * first time we've looked at the correct iclog buf) and the
3293 * buffer before us is going to be sync'ed. The reason for this
3294 * is that if we are doing sync transactions here, by waiting
3295 * for the previous I/O to complete, we can allow a few more
3296 * transactions into this iclog before we close it down.
3297 *
3298 * Otherwise, we mark the buffer WANT_SYNC, and bump up the
3299 * refcnt so we can release the log (which drops the ref count).
3300 * The state switch keeps new transaction commits from using
3301 * this buffer. When the current commits finish writing into
3302 * the buffer, the refcount will drop to zero and the buffer
3303 * will go out then.
3304 */
3305 if (!already_slept &&
3306 (iclog->ic_prev->ic_state == XLOG_STATE_WANT_SYNC ||
3307 iclog->ic_prev->ic_state == XLOG_STATE_SYNCING)) {
3308 xlog_wait(&iclog->ic_prev->ic_write_wait,
3309 &log->l_icloglock);
3310 return -EAGAIN;
3311 }
3312 if (xlog_force_and_check_iclog(iclog, &completed))
3313 goto out_error;
3314 if (log_flushed)
3315 *log_flushed = 1;
3316 if (completed)
3317 goto out_unlock;
3318 break;
3319 case XLOG_STATE_WANT_SYNC:
3320 /*
3321 * This iclog may contain the checkpoint pushed by the
3322 * xlog_cil_force_seq() call, but there are other writers still
3323 * accessing it so it hasn't been pushed to disk yet. Like the
3324 * ACTIVE case above, we need to make sure caches are flushed
3325 * when this iclog is written.
3326 */
3327 iclog->ic_flags |= XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA;
3328 break;
3329 default:
3330 /*
3331 * The entire checkpoint was written by the CIL force and is on
3332 * its way to disk already. It will be stable when it
3333 * completes, so we don't need to manipulate caches here at all.
3334 * We just need to wait for completion if necessary.
3335 */
3336 break;
3337 }
3338
3339 if (flags & XFS_LOG_SYNC)
3340 return xlog_wait_on_iclog(iclog);
3341out_unlock:
3342 spin_unlock(&log->l_icloglock);
3343 return 0;
3344out_error:
3345 spin_unlock(&log->l_icloglock);
3346 return -EIO;
3347}
3348
3349/*
3350 * Force the log to a specific checkpoint sequence.
3351 *
3352 * First force the CIL so that all the required changes have been flushed to the
3353 * iclogs. If the CIL force completed it will return a commit LSN that indicates
3354 * the iclog that needs to be flushed to stable storage. If the caller needs
3355 * a synchronous log force, we will wait on the iclog with the LSN returned by
3356 * xlog_cil_force_seq() to be completed.
3357 */
3358int
3359xfs_log_force_seq(
3360 struct xfs_mount *mp,
3361 xfs_csn_t seq,
3362 uint flags,
3363 int *log_flushed)
3364{
3365 struct xlog *log = mp->m_log;
3366 xfs_lsn_t lsn;
3367 int ret;
3368 ASSERT(seq != 0);
3369
3370 XFS_STATS_INC(mp, xs_log_force);
3371 trace_xfs_log_force(mp, seq, _RET_IP_);
3372
3373 lsn = xlog_cil_force_seq(log, seq);
3374 if (lsn == NULLCOMMITLSN)
3375 return 0;
3376
3377 ret = xlog_force_lsn(log, lsn, flags, log_flushed, false);
3378 if (ret == -EAGAIN) {
3379 XFS_STATS_INC(mp, xs_log_force_sleep);
3380 ret = xlog_force_lsn(log, lsn, flags, log_flushed, true);
3381 }
3382 return ret;
3383}
3384
3385/*
3386 * Free a used ticket when its refcount falls to zero.
3387 */
3388void
3389xfs_log_ticket_put(
3390 xlog_ticket_t *ticket)
3391{
3392 ASSERT(atomic_read(&ticket->t_ref) > 0);
3393 if (atomic_dec_and_test(&ticket->t_ref))
3394 kmem_cache_free(xfs_log_ticket_cache, ticket);
3395}
3396
3397xlog_ticket_t *
3398xfs_log_ticket_get(
3399 xlog_ticket_t *ticket)
3400{
3401 ASSERT(atomic_read(&ticket->t_ref) > 0);
3402 atomic_inc(&ticket->t_ref);
3403 return ticket;
3404}
3405
3406/*
3407 * Figure out the total log space unit (in bytes) that would be
3408 * required for a log ticket.
3409 */
3410static int
3411xlog_calc_unit_res(
3412 struct xlog *log,
3413 int unit_bytes,
3414 int *niclogs)
3415{
3416 int iclog_space;
3417 uint num_headers;
3418
3419 /*
3420 * Permanent reservations have up to 'cnt'-1 active log operations
3421 * in the log. A unit in this case is the amount of space for one
3422 * of these log operations. Normal reservations have a cnt of 1
3423 * and their unit amount is the total amount of space required.
3424 *
3425 * The following lines of code account for non-transaction data
3426 * which occupy space in the on-disk log.
3427 *
3428 * Normal form of a transaction is:
3429 * <oph><trans-hdr><start-oph><reg1-oph><reg1><reg2-oph>...<commit-oph>
3430 * and then there are LR hdrs, split-recs and roundoff at end of syncs.
3431 *
3432 * We need to account for all the leadup data and trailer data
3433 * around the transaction data.
3434 * And then we need to account for the worst case in terms of using
3435 * more space.
3436 * The worst case will happen if:
3437 * - the placement of the transaction happens to be such that the
3438 * roundoff is at its maximum
3439 * - the transaction data is synced before the commit record is synced
3440 * i.e. <transaction-data><roundoff> | <commit-rec><roundoff>
3441 * Therefore the commit record is in its own Log Record.
3442 * This can happen as the commit record is called with its
3443 * own region to xlog_write().
3444 * This then means that in the worst case, roundoff can happen for
3445 * the commit-rec as well.
3446 * The commit-rec is smaller than padding in this scenario and so it is
3447 * not added separately.
3448 */
3449
3450 /* for trans header */
3451 unit_bytes += sizeof(xlog_op_header_t);
3452 unit_bytes += sizeof(xfs_trans_header_t);
3453
3454 /* for start-rec */
3455 unit_bytes += sizeof(xlog_op_header_t);
3456
3457 /*
3458 * for LR headers - the space for data in an iclog is the size minus
3459 * the space used for the headers. If we use the iclog size, then we
3460 * undercalculate the number of headers required.
3461 *
3462 * Furthermore - the addition of op headers for split-recs might
3463 * increase the space required enough to require more log and op
3464 * headers, so take that into account too.
3465 *
3466 * IMPORTANT: This reservation makes the assumption that if this
3467 * transaction is the first in an iclog and hence has the LR headers
3468 * accounted to it, then the remaining space in the iclog is
3469 * exclusively for this transaction. i.e. if the transaction is larger
3470 * than the iclog, it will be the only thing in that iclog.
3471 * Fundamentally, this means we must pass the entire log vector to
3472 * xlog_write to guarantee this.
3473 */
3474 iclog_space = log->l_iclog_size - log->l_iclog_hsize;
3475 num_headers = howmany(unit_bytes, iclog_space);
3476
3477 /* for split-recs - ophdrs added when data split over LRs */
3478 unit_bytes += sizeof(xlog_op_header_t) * num_headers;
3479
3480 /* add extra header reservations if we overrun */
3481 while (!num_headers ||
3482 howmany(unit_bytes, iclog_space) > num_headers) {
3483 unit_bytes += sizeof(xlog_op_header_t);
3484 num_headers++;
3485 }
3486 unit_bytes += log->l_iclog_hsize * num_headers;
3487
3488 /* for commit-rec LR header - note: padding will subsume the ophdr */
3489 unit_bytes += log->l_iclog_hsize;
3490
3491 /* roundoff padding for transaction data and one for commit record */
3492 unit_bytes += 2 * log->l_iclog_roundoff;
3493
3494 if (niclogs)
3495 *niclogs = num_headers;
3496 return unit_bytes;
3497}
3498
3499int
3500xfs_log_calc_unit_res(
3501 struct xfs_mount *mp,
3502 int unit_bytes)
3503{
3504 return xlog_calc_unit_res(mp->m_log, unit_bytes, NULL);
3505}
3506
3507/*
3508 * Allocate and initialise a new log ticket.
3509 */
3510struct xlog_ticket *
3511xlog_ticket_alloc(
3512 struct xlog *log,
3513 int unit_bytes,
3514 int cnt,
3515 bool permanent)
3516{
3517 struct xlog_ticket *tic;
3518 int unit_res;
3519
3520 tic = kmem_cache_zalloc(xfs_log_ticket_cache, GFP_NOFS | __GFP_NOFAIL);
3521
3522 unit_res = xlog_calc_unit_res(log, unit_bytes, &tic->t_iclog_hdrs);
3523
3524 atomic_set(&tic->t_ref, 1);
3525 tic->t_task = current;
3526 INIT_LIST_HEAD(&tic->t_queue);
3527 tic->t_unit_res = unit_res;
3528 tic->t_curr_res = unit_res;
3529 tic->t_cnt = cnt;
3530 tic->t_ocnt = cnt;
3531 tic->t_tid = get_random_u32();
3532 if (permanent)
3533 tic->t_flags |= XLOG_TIC_PERM_RESERV;
3534
3535 return tic;
3536}
3537
3538#if defined(DEBUG)
3539/*
3540 * Check to make sure the grant write head didn't just over lap the tail. If
3541 * the cycles are the same, we can't be overlapping. Otherwise, make sure that
3542 * the cycles differ by exactly one and check the byte count.
3543 *
3544 * This check is run unlocked, so can give false positives. Rather than assert
3545 * on failures, use a warn-once flag and a panic tag to allow the admin to
3546 * determine if they want to panic the machine when such an error occurs. For
3547 * debug kernels this will have the same effect as using an assert but, unlinke
3548 * an assert, it can be turned off at runtime.
3549 */
3550STATIC void
3551xlog_verify_grant_tail(
3552 struct xlog *log)
3553{
3554 int tail_cycle, tail_blocks;
3555 int cycle, space;
3556
3557 xlog_crack_grant_head(&log->l_write_head.grant, &cycle, &space);
3558 xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_blocks);
3559 if (tail_cycle != cycle) {
3560 if (cycle - 1 != tail_cycle &&
3561 !test_and_set_bit(XLOG_TAIL_WARN, &log->l_opstate)) {
3562 xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
3563 "%s: cycle - 1 != tail_cycle", __func__);
3564 }
3565
3566 if (space > BBTOB(tail_blocks) &&
3567 !test_and_set_bit(XLOG_TAIL_WARN, &log->l_opstate)) {
3568 xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
3569 "%s: space > BBTOB(tail_blocks)", __func__);
3570 }
3571 }
3572}
3573
3574/* check if it will fit */
3575STATIC void
3576xlog_verify_tail_lsn(
3577 struct xlog *log,
3578 struct xlog_in_core *iclog)
3579{
3580 xfs_lsn_t tail_lsn = be64_to_cpu(iclog->ic_header.h_tail_lsn);
3581 int blocks;
3582
3583 if (CYCLE_LSN(tail_lsn) == log->l_prev_cycle) {
3584 blocks =
3585 log->l_logBBsize - (log->l_prev_block - BLOCK_LSN(tail_lsn));
3586 if (blocks < BTOBB(iclog->ic_offset)+BTOBB(log->l_iclog_hsize))
3587 xfs_emerg(log->l_mp, "%s: ran out of log space", __func__);
3588 } else {
3589 ASSERT(CYCLE_LSN(tail_lsn)+1 == log->l_prev_cycle);
3590
3591 if (BLOCK_LSN(tail_lsn) == log->l_prev_block)
3592 xfs_emerg(log->l_mp, "%s: tail wrapped", __func__);
3593
3594 blocks = BLOCK_LSN(tail_lsn) - log->l_prev_block;
3595 if (blocks < BTOBB(iclog->ic_offset) + 1)
3596 xfs_emerg(log->l_mp, "%s: ran out of log space", __func__);
3597 }
3598}
3599
3600/*
3601 * Perform a number of checks on the iclog before writing to disk.
3602 *
3603 * 1. Make sure the iclogs are still circular
3604 * 2. Make sure we have a good magic number
3605 * 3. Make sure we don't have magic numbers in the data
3606 * 4. Check fields of each log operation header for:
3607 * A. Valid client identifier
3608 * B. tid ptr value falls in valid ptr space (user space code)
3609 * C. Length in log record header is correct according to the
3610 * individual operation headers within record.
3611 * 5. When a bwrite will occur within 5 blocks of the front of the physical
3612 * log, check the preceding blocks of the physical log to make sure all
3613 * the cycle numbers agree with the current cycle number.
3614 */
3615STATIC void
3616xlog_verify_iclog(
3617 struct xlog *log,
3618 struct xlog_in_core *iclog,
3619 int count)
3620{
3621 xlog_op_header_t *ophead;
3622 xlog_in_core_t *icptr;
3623 xlog_in_core_2_t *xhdr;
3624 void *base_ptr, *ptr, *p;
3625 ptrdiff_t field_offset;
3626 uint8_t clientid;
3627 int len, i, j, k, op_len;
3628 int idx;
3629
3630 /* check validity of iclog pointers */
3631 spin_lock(&log->l_icloglock);
3632 icptr = log->l_iclog;
3633 for (i = 0; i < log->l_iclog_bufs; i++, icptr = icptr->ic_next)
3634 ASSERT(icptr);
3635
3636 if (icptr != log->l_iclog)
3637 xfs_emerg(log->l_mp, "%s: corrupt iclog ring", __func__);
3638 spin_unlock(&log->l_icloglock);
3639
3640 /* check log magic numbers */
3641 if (iclog->ic_header.h_magicno != cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
3642 xfs_emerg(log->l_mp, "%s: invalid magic num", __func__);
3643
3644 base_ptr = ptr = &iclog->ic_header;
3645 p = &iclog->ic_header;
3646 for (ptr += BBSIZE; ptr < base_ptr + count; ptr += BBSIZE) {
3647 if (*(__be32 *)ptr == cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
3648 xfs_emerg(log->l_mp, "%s: unexpected magic num",
3649 __func__);
3650 }
3651
3652 /* check fields */
3653 len = be32_to_cpu(iclog->ic_header.h_num_logops);
3654 base_ptr = ptr = iclog->ic_datap;
3655 ophead = ptr;
3656 xhdr = iclog->ic_data;
3657 for (i = 0; i < len; i++) {
3658 ophead = ptr;
3659
3660 /* clientid is only 1 byte */
3661 p = &ophead->oh_clientid;
3662 field_offset = p - base_ptr;
3663 if (field_offset & 0x1ff) {
3664 clientid = ophead->oh_clientid;
3665 } else {
3666 idx = BTOBBT((void *)&ophead->oh_clientid - iclog->ic_datap);
3667 if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
3668 j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3669 k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3670 clientid = xlog_get_client_id(
3671 xhdr[j].hic_xheader.xh_cycle_data[k]);
3672 } else {
3673 clientid = xlog_get_client_id(
3674 iclog->ic_header.h_cycle_data[idx]);
3675 }
3676 }
3677 if (clientid != XFS_TRANSACTION && clientid != XFS_LOG) {
3678 xfs_warn(log->l_mp,
3679 "%s: op %d invalid clientid %d op "PTR_FMT" offset 0x%lx",
3680 __func__, i, clientid, ophead,
3681 (unsigned long)field_offset);
3682 }
3683
3684 /* check length */
3685 p = &ophead->oh_len;
3686 field_offset = p - base_ptr;
3687 if (field_offset & 0x1ff) {
3688 op_len = be32_to_cpu(ophead->oh_len);
3689 } else {
3690 idx = BTOBBT((void *)&ophead->oh_len - iclog->ic_datap);
3691 if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
3692 j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3693 k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3694 op_len = be32_to_cpu(xhdr[j].hic_xheader.xh_cycle_data[k]);
3695 } else {
3696 op_len = be32_to_cpu(iclog->ic_header.h_cycle_data[idx]);
3697 }
3698 }
3699 ptr += sizeof(xlog_op_header_t) + op_len;
3700 }
3701}
3702#endif
3703
3704/*
3705 * Perform a forced shutdown on the log.
3706 *
3707 * This can be called from low level log code to trigger a shutdown, or from the
3708 * high level mount shutdown code when the mount shuts down.
3709 *
3710 * Our main objectives here are to make sure that:
3711 * a. if the shutdown was not due to a log IO error, flush the logs to
3712 * disk. Anything modified after this is ignored.
3713 * b. the log gets atomically marked 'XLOG_IO_ERROR' for all interested
3714 * parties to find out. Nothing new gets queued after this is done.
3715 * c. Tasks sleeping on log reservations, pinned objects and
3716 * other resources get woken up.
3717 * d. The mount is also marked as shut down so that log triggered shutdowns
3718 * still behave the same as if they called xfs_forced_shutdown().
3719 *
3720 * Return true if the shutdown cause was a log IO error and we actually shut the
3721 * log down.
3722 */
3723bool
3724xlog_force_shutdown(
3725 struct xlog *log,
3726 uint32_t shutdown_flags)
3727{
3728 bool log_error = (shutdown_flags & SHUTDOWN_LOG_IO_ERROR);
3729
3730 if (!log)
3731 return false;
3732
3733 /*
3734 * Flush all the completed transactions to disk before marking the log
3735 * being shut down. We need to do this first as shutting down the log
3736 * before the force will prevent the log force from flushing the iclogs
3737 * to disk.
3738 *
3739 * When we are in recovery, there are no transactions to flush, and
3740 * we don't want to touch the log because we don't want to perturb the
3741 * current head/tail for future recovery attempts. Hence we need to
3742 * avoid a log force in this case.
3743 *
3744 * If we are shutting down due to a log IO error, then we must avoid
3745 * trying to write the log as that may just result in more IO errors and
3746 * an endless shutdown/force loop.
3747 */
3748 if (!log_error && !xlog_in_recovery(log))
3749 xfs_log_force(log->l_mp, XFS_LOG_SYNC);
3750
3751 /*
3752 * Atomically set the shutdown state. If the shutdown state is already
3753 * set, there someone else is performing the shutdown and so we are done
3754 * here. This should never happen because we should only ever get called
3755 * once by the first shutdown caller.
3756 *
3757 * Much of the log state machine transitions assume that shutdown state
3758 * cannot change once they hold the log->l_icloglock. Hence we need to
3759 * hold that lock here, even though we use the atomic test_and_set_bit()
3760 * operation to set the shutdown state.
3761 */
3762 spin_lock(&log->l_icloglock);
3763 if (test_and_set_bit(XLOG_IO_ERROR, &log->l_opstate)) {
3764 spin_unlock(&log->l_icloglock);
3765 return false;
3766 }
3767 spin_unlock(&log->l_icloglock);
3768
3769 /*
3770 * If this log shutdown also sets the mount shutdown state, issue a
3771 * shutdown warning message.
3772 */
3773 if (!test_and_set_bit(XFS_OPSTATE_SHUTDOWN, &log->l_mp->m_opstate)) {
3774 xfs_alert_tag(log->l_mp, XFS_PTAG_SHUTDOWN_LOGERROR,
3775"Filesystem has been shut down due to log error (0x%x).",
3776 shutdown_flags);
3777 xfs_alert(log->l_mp,
3778"Please unmount the filesystem and rectify the problem(s).");
3779 if (xfs_error_level >= XFS_ERRLEVEL_HIGH)
3780 xfs_stack_trace();
3781 }
3782
3783 /*
3784 * We don't want anybody waiting for log reservations after this. That
3785 * means we have to wake up everybody queued up on reserveq as well as
3786 * writeq. In addition, we make sure in xlog_{re}grant_log_space that
3787 * we don't enqueue anything once the SHUTDOWN flag is set, and this
3788 * action is protected by the grant locks.
3789 */
3790 xlog_grant_head_wake_all(&log->l_reserve_head);
3791 xlog_grant_head_wake_all(&log->l_write_head);
3792
3793 /*
3794 * Wake up everybody waiting on xfs_log_force. Wake the CIL push first
3795 * as if the log writes were completed. The abort handling in the log
3796 * item committed callback functions will do this again under lock to
3797 * avoid races.
3798 */
3799 spin_lock(&log->l_cilp->xc_push_lock);
3800 wake_up_all(&log->l_cilp->xc_start_wait);
3801 wake_up_all(&log->l_cilp->xc_commit_wait);
3802 spin_unlock(&log->l_cilp->xc_push_lock);
3803
3804 spin_lock(&log->l_icloglock);
3805 xlog_state_shutdown_callbacks(log);
3806 spin_unlock(&log->l_icloglock);
3807
3808 wake_up_var(&log->l_opstate);
3809 return log_error;
3810}
3811
3812STATIC int
3813xlog_iclogs_empty(
3814 struct xlog *log)
3815{
3816 xlog_in_core_t *iclog;
3817
3818 iclog = log->l_iclog;
3819 do {
3820 /* endianness does not matter here, zero is zero in
3821 * any language.
3822 */
3823 if (iclog->ic_header.h_num_logops)
3824 return 0;
3825 iclog = iclog->ic_next;
3826 } while (iclog != log->l_iclog);
3827 return 1;
3828}
3829
3830/*
3831 * Verify that an LSN stamped into a piece of metadata is valid. This is
3832 * intended for use in read verifiers on v5 superblocks.
3833 */
3834bool
3835xfs_log_check_lsn(
3836 struct xfs_mount *mp,
3837 xfs_lsn_t lsn)
3838{
3839 struct xlog *log = mp->m_log;
3840 bool valid;
3841
3842 /*
3843 * norecovery mode skips mount-time log processing and unconditionally
3844 * resets the in-core LSN. We can't validate in this mode, but
3845 * modifications are not allowed anyways so just return true.
3846 */
3847 if (xfs_has_norecovery(mp))
3848 return true;
3849
3850 /*
3851 * Some metadata LSNs are initialized to NULL (e.g., the agfl). This is
3852 * handled by recovery and thus safe to ignore here.
3853 */
3854 if (lsn == NULLCOMMITLSN)
3855 return true;
3856
3857 valid = xlog_valid_lsn(mp->m_log, lsn);
3858
3859 /* warn the user about what's gone wrong before verifier failure */
3860 if (!valid) {
3861 spin_lock(&log->l_icloglock);
3862 xfs_warn(mp,
3863"Corruption warning: Metadata has LSN (%d:%d) ahead of current LSN (%d:%d). "
3864"Please unmount and run xfs_repair (>= v4.3) to resolve.",
3865 CYCLE_LSN(lsn), BLOCK_LSN(lsn),
3866 log->l_curr_cycle, log->l_curr_block);
3867 spin_unlock(&log->l_icloglock);
3868 }
3869
3870 return valid;
3871}
3872
3873/*
3874 * Notify the log that we're about to start using a feature that is protected
3875 * by a log incompat feature flag. This will prevent log covering from
3876 * clearing those flags.
3877 */
3878void
3879xlog_use_incompat_feat(
3880 struct xlog *log)
3881{
3882 down_read(&log->l_incompat_users);
3883}
3884
3885/* Notify the log that we've finished using log incompat features. */
3886void
3887xlog_drop_incompat_feat(
3888 struct xlog *log)
3889{
3890 up_read(&log->l_incompat_users);
3891}