2 * Copyright (c) 2010 Red Hat, Inc. All Rights Reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation.
8 * This program is distributed in the hope that it would be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write the Free Software Foundation,
15 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 #include "xfs_format.h"
21 #include "xfs_log_format.h"
22 #include "xfs_shared.h"
23 #include "xfs_trans_resv.h"
24 #include "xfs_mount.h"
25 #include "xfs_error.h"
26 #include "xfs_alloc.h"
27 #include "xfs_extent_busy.h"
28 #include "xfs_discard.h"
29 #include "xfs_trans.h"
30 #include "xfs_trans_priv.h"
32 #include "xfs_log_priv.h"
35 * Allocate a new ticket. Failing to get a new ticket makes it really hard to
36 * recover, so we don't allow failure here. Also, we allocate in a context that
37 * we don't want to be issuing transactions from, so we need to tell the
38 * allocation code this as well.
40 * We don't reserve any space for the ticket - we are going to steal whatever
41 * space we require from transactions as they commit. To ensure we reserve all
42 * the space required, we need to set the current reservation of the ticket to
43 * zero so that we know to steal the initial transaction overhead from the
44 * first transaction commit.
46 static struct xlog_ticket
*
47 xlog_cil_ticket_alloc(
50 struct xlog_ticket
*tic
;
52 tic
= xlog_ticket_alloc(log
, 0, 1, XFS_TRANSACTION
, 0,
56 * set the current reservation to zero so we know to steal the basic
57 * transaction overhead reservation from the first transaction commit.
64 * After the first stage of log recovery is done, we know where the head and
65 * tail of the log are. We need this log initialisation done before we can
66 * initialise the first CIL checkpoint context.
68 * Here we allocate a log ticket to track space usage during a CIL push. This
69 * ticket is passed to xlog_write() directly so that we don't slowly leak log
70 * space by failing to account for space used by log headers and additional
71 * region headers for split regions.
74 xlog_cil_init_post_recovery(
77 log
->l_cilp
->xc_ctx
->ticket
= xlog_cil_ticket_alloc(log
);
78 log
->l_cilp
->xc_ctx
->sequence
= 1;
82 * Prepare the log item for insertion into the CIL. Calculate the difference in
83 * log space and vectors it will consume, and if it is a new item pin it as
89 struct xfs_log_vec
*lv
,
90 struct xfs_log_vec
*old_lv
,
94 /* Account for the new LV being passed in */
95 if (lv
->lv_buf_len
!= XFS_LOG_VEC_ORDERED
) {
96 *diff_len
+= lv
->lv_bytes
;
97 *diff_iovecs
+= lv
->lv_niovecs
;
101 * If there is no old LV, this is the first time we've seen the item in
102 * this CIL context and so we need to pin it. If we are replacing the
103 * old_lv, then remove the space it accounts for and free it.
106 lv
->lv_item
->li_ops
->iop_pin(lv
->lv_item
);
107 else if (old_lv
!= lv
) {
108 ASSERT(lv
->lv_buf_len
!= XFS_LOG_VEC_ORDERED
);
110 *diff_len
-= old_lv
->lv_bytes
;
111 *diff_iovecs
-= old_lv
->lv_niovecs
;
115 /* attach new log vector to log item */
116 lv
->lv_item
->li_lv
= lv
;
119 * If this is the first time the item is being committed to the
120 * CIL, store the sequence number on the log item so we can
121 * tell in future commits whether this is the first checkpoint
122 * the item is being committed into.
124 if (!lv
->lv_item
->li_seq
)
125 lv
->lv_item
->li_seq
= log
->l_cilp
->xc_ctx
->sequence
;
129 * Format log item into a flat buffers
131 * For delayed logging, we need to hold a formatted buffer containing all the
132 * changes on the log item. This enables us to relog the item in memory and
133 * write it out asynchronously without needing to relock the object that was
134 * modified at the time it gets written into the iclog.
136 * This function builds a vector for the changes in each log item in the
137 * transaction. It then works out the length of the buffer needed for each log
138 * item, allocates them and formats the vector for the item into the buffer.
139 * The buffer is then attached to the log item are then inserted into the
140 * Committed Item List for tracking until the next checkpoint is written out.
142 * We don't set up region headers during this process; we simply copy the
143 * regions into the flat buffer. We can do this because we still have to do a
144 * formatting step to write the regions into the iclog buffer. Writing the
145 * ophdrs during the iclog write means that we can support splitting large
146 * regions across iclog boundares without needing a change in the format of the
147 * item/region encapsulation.
149 * Hence what we need to do now is change the rewrite the vector array to point
150 * to the copied region inside the buffer we just allocated. This allows us to
151 * format the regions into the iclog as though they are being formatted
152 * directly out of the objects themselves.
155 xlog_cil_insert_format_items(
157 struct xfs_trans
*tp
,
161 struct xfs_log_item_desc
*lidp
;
164 /* Bail out if we didn't find a log item. */
165 if (list_empty(&tp
->t_items
)) {
170 list_for_each_entry(lidp
, &tp
->t_items
, lid_trans
) {
171 struct xfs_log_item
*lip
= lidp
->lid_item
;
172 struct xfs_log_vec
*lv
;
173 struct xfs_log_vec
*old_lv
;
177 bool ordered
= false;
179 /* Skip items which aren't dirty in this transaction. */
180 if (!(lidp
->lid_flags
& XFS_LID_DIRTY
))
183 /* get number of vecs and size of data to be stored */
184 lip
->li_ops
->iop_size(lip
, &niovecs
, &nbytes
);
186 /* Skip items that do not have any vectors for writing */
191 * Ordered items need to be tracked but we do not wish to write
192 * them. We need a logvec to track the object, but we do not
193 * need an iovec or buffer to be allocated for copying data.
195 if (niovecs
== XFS_LOG_VEC_ORDERED
) {
202 * We 64-bit align the length of each iovec so that the start
203 * of the next one is naturally aligned. We'll need to
204 * account for that slack space here. Then round nbytes up
205 * to 64-bit alignment so that the initial buffer alignment is
206 * easy to calculate and verify.
208 nbytes
+= niovecs
* sizeof(uint64_t);
209 nbytes
= round_up(nbytes
, sizeof(uint64_t));
211 /* grab the old item if it exists for reservation accounting */
215 * The data buffer needs to start 64-bit aligned, so round up
216 * that space to ensure we can align it appropriately and not
217 * overrun the buffer.
220 round_up((sizeof(struct xfs_log_vec
) +
221 niovecs
* sizeof(struct xfs_log_iovec
)),
224 /* compare to existing item size */
225 if (lip
->li_lv
&& buf_size
<= lip
->li_lv
->lv_size
) {
226 /* same or smaller, optimise common overwrite case */
234 * set the item up as though it is a new insertion so
235 * that the space reservation accounting is correct.
237 *diff_iovecs
-= lv
->lv_niovecs
;
238 *diff_len
-= lv
->lv_bytes
;
240 /* allocate new data chunk */
241 lv
= kmem_zalloc(buf_size
, KM_SLEEP
|KM_NOFS
);
243 lv
->lv_size
= buf_size
;
245 /* track as an ordered logvec */
246 ASSERT(lip
->li_lv
== NULL
);
247 lv
->lv_buf_len
= XFS_LOG_VEC_ORDERED
;
250 lv
->lv_iovecp
= (struct xfs_log_iovec
*)&lv
[1];
253 /* Ensure the lv is set up according to ->iop_size */
254 lv
->lv_niovecs
= niovecs
;
256 /* The allocated data region lies beyond the iovec region */
259 lv
->lv_buf
= (char *)lv
+ buf_size
- nbytes
;
260 ASSERT(IS_ALIGNED((unsigned long)lv
->lv_buf
, sizeof(uint64_t)));
262 lip
->li_ops
->iop_format(lip
, lv
);
264 ASSERT(lv
->lv_buf_len
<= nbytes
);
265 xfs_cil_prepare_item(log
, lv
, old_lv
, diff_len
, diff_iovecs
);
270 * Insert the log items into the CIL and calculate the difference in space
271 * consumed by the item. Add the space to the checkpoint ticket and calculate
272 * if the change requires additional log metadata. If it does, take that space
273 * as well. Remove the amount of space we added to the checkpoint ticket from
274 * the current transaction ticket so that the accounting works out correctly.
277 xlog_cil_insert_items(
279 struct xfs_trans
*tp
)
281 struct xfs_cil
*cil
= log
->l_cilp
;
282 struct xfs_cil_ctx
*ctx
= cil
->xc_ctx
;
283 struct xfs_log_item_desc
*lidp
;
291 * We can do this safely because the context can't checkpoint until we
292 * are done so it doesn't matter exactly how we update the CIL.
294 xlog_cil_insert_format_items(log
, tp
, &len
, &diff_iovecs
);
297 * Now (re-)position everything modified at the tail of the CIL.
298 * We do this here so we only need to take the CIL lock once during
299 * the transaction commit.
301 spin_lock(&cil
->xc_cil_lock
);
302 list_for_each_entry(lidp
, &tp
->t_items
, lid_trans
) {
303 struct xfs_log_item
*lip
= lidp
->lid_item
;
305 /* Skip items which aren't dirty in this transaction. */
306 if (!(lidp
->lid_flags
& XFS_LID_DIRTY
))
310 * Only move the item if it isn't already at the tail. This is
311 * to prevent a transient list_empty() state when reinserting
312 * an item that is already the only item in the CIL.
314 if (!list_is_last(&lip
->li_cil
, &cil
->xc_cil
))
315 list_move_tail(&lip
->li_cil
, &cil
->xc_cil
);
318 /* account for space used by new iovec headers */
319 len
+= diff_iovecs
* sizeof(xlog_op_header_t
);
320 ctx
->nvecs
+= diff_iovecs
;
322 /* attach the transaction to the CIL if it has any busy extents */
323 if (!list_empty(&tp
->t_busy
))
324 list_splice_init(&tp
->t_busy
, &ctx
->busy_extents
);
327 * Now transfer enough transaction reservation to the context ticket
328 * for the checkpoint. The context ticket is special - the unit
329 * reservation has to grow as well as the current reservation as we
330 * steal from tickets so we can correctly determine the space used
331 * during the transaction commit.
333 if (ctx
->ticket
->t_curr_res
== 0) {
334 ctx
->ticket
->t_curr_res
= ctx
->ticket
->t_unit_res
;
335 tp
->t_ticket
->t_curr_res
-= ctx
->ticket
->t_unit_res
;
338 /* do we need space for more log record headers? */
339 iclog_space
= log
->l_iclog_size
- log
->l_iclog_hsize
;
340 if (len
> 0 && (ctx
->space_used
/ iclog_space
!=
341 (ctx
->space_used
+ len
) / iclog_space
)) {
344 hdrs
= (len
+ iclog_space
- 1) / iclog_space
;
345 /* need to take into account split region headers, too */
346 hdrs
*= log
->l_iclog_hsize
+ sizeof(struct xlog_op_header
);
347 ctx
->ticket
->t_unit_res
+= hdrs
;
348 ctx
->ticket
->t_curr_res
+= hdrs
;
349 tp
->t_ticket
->t_curr_res
-= hdrs
;
350 ASSERT(tp
->t_ticket
->t_curr_res
>= len
);
352 tp
->t_ticket
->t_curr_res
-= len
;
353 ctx
->space_used
+= len
;
355 spin_unlock(&cil
->xc_cil_lock
);
359 xlog_cil_free_logvec(
360 struct xfs_log_vec
*log_vector
)
362 struct xfs_log_vec
*lv
;
364 for (lv
= log_vector
; lv
; ) {
365 struct xfs_log_vec
*next
= lv
->lv_next
;
372 * Mark all items committed and clear busy extents. We free the log vector
373 * chains in a separate pass so that we unpin the log items as quickly as
381 struct xfs_cil_ctx
*ctx
= args
;
382 struct xfs_mount
*mp
= ctx
->cil
->xc_log
->l_mp
;
384 xfs_trans_committed_bulk(ctx
->cil
->xc_log
->l_ailp
, ctx
->lv_chain
,
385 ctx
->start_lsn
, abort
);
387 xfs_extent_busy_sort(&ctx
->busy_extents
);
388 xfs_extent_busy_clear(mp
, &ctx
->busy_extents
,
389 (mp
->m_flags
& XFS_MOUNT_DISCARD
) && !abort
);
392 * If we are aborting the commit, wake up anyone waiting on the
393 * committing list. If we don't, then a shutdown we can leave processes
394 * waiting in xlog_cil_force_lsn() waiting on a sequence commit that
395 * will never happen because we aborted it.
397 spin_lock(&ctx
->cil
->xc_push_lock
);
399 wake_up_all(&ctx
->cil
->xc_commit_wait
);
400 list_del(&ctx
->committing
);
401 spin_unlock(&ctx
->cil
->xc_push_lock
);
403 xlog_cil_free_logvec(ctx
->lv_chain
);
405 if (!list_empty(&ctx
->busy_extents
)) {
406 ASSERT(mp
->m_flags
& XFS_MOUNT_DISCARD
);
408 xfs_discard_extents(mp
, &ctx
->busy_extents
);
409 xfs_extent_busy_clear(mp
, &ctx
->busy_extents
, false);
416 * Push the Committed Item List to the log. If @push_seq flag is zero, then it
417 * is a background flush and so we can chose to ignore it. Otherwise, if the
418 * current sequence is the same as @push_seq we need to do a flush. If
419 * @push_seq is less than the current sequence, then it has already been
420 * flushed and we don't need to do anything - the caller will wait for it to
421 * complete if necessary.
423 * @push_seq is a value rather than a flag because that allows us to do an
424 * unlocked check of the sequence number for a match. Hence we can allows log
425 * forces to run racily and not issue pushes for the same sequence twice. If we
426 * get a race between multiple pushes for the same sequence they will block on
427 * the first one and then abort, hence avoiding needless pushes.
433 struct xfs_cil
*cil
= log
->l_cilp
;
434 struct xfs_log_vec
*lv
;
435 struct xfs_cil_ctx
*ctx
;
436 struct xfs_cil_ctx
*new_ctx
;
437 struct xlog_in_core
*commit_iclog
;
438 struct xlog_ticket
*tic
;
441 struct xfs_trans_header thdr
;
442 struct xfs_log_iovec lhdr
;
443 struct xfs_log_vec lvhdr
= { NULL
};
444 xfs_lsn_t commit_lsn
;
450 new_ctx
= kmem_zalloc(sizeof(*new_ctx
), KM_SLEEP
|KM_NOFS
);
451 new_ctx
->ticket
= xlog_cil_ticket_alloc(log
);
453 down_write(&cil
->xc_ctx_lock
);
456 spin_lock(&cil
->xc_push_lock
);
457 push_seq
= cil
->xc_push_seq
;
458 ASSERT(push_seq
<= ctx
->sequence
);
461 * Check if we've anything to push. If there is nothing, then we don't
462 * move on to a new sequence number and so we have to be able to push
463 * this sequence again later.
465 if (list_empty(&cil
->xc_cil
)) {
466 cil
->xc_push_seq
= 0;
467 spin_unlock(&cil
->xc_push_lock
);
472 /* check for a previously pushed seqeunce */
473 if (push_seq
< cil
->xc_ctx
->sequence
) {
474 spin_unlock(&cil
->xc_push_lock
);
479 * We are now going to push this context, so add it to the committing
480 * list before we do anything else. This ensures that anyone waiting on
481 * this push can easily detect the difference between a "push in
482 * progress" and "CIL is empty, nothing to do".
484 * IOWs, a wait loop can now check for:
485 * the current sequence not being found on the committing list;
487 * an unchanged sequence number
488 * to detect a push that had nothing to do and therefore does not need
489 * waiting on. If the CIL is not empty, we get put on the committing
490 * list before emptying the CIL and bumping the sequence number. Hence
491 * an empty CIL and an unchanged sequence number means we jumped out
492 * above after doing nothing.
494 * Hence the waiter will either find the commit sequence on the
495 * committing list or the sequence number will be unchanged and the CIL
496 * still dirty. In that latter case, the push has not yet started, and
497 * so the waiter will have to continue trying to check the CIL
498 * committing list until it is found. In extreme cases of delay, the
499 * sequence may fully commit between the attempts the wait makes to wait
500 * on the commit sequence.
502 list_add(&ctx
->committing
, &cil
->xc_committing
);
503 spin_unlock(&cil
->xc_push_lock
);
506 * pull all the log vectors off the items in the CIL, and
507 * remove the items from the CIL. We don't need the CIL lock
508 * here because it's only needed on the transaction commit
509 * side which is currently locked out by the flush lock.
513 while (!list_empty(&cil
->xc_cil
)) {
514 struct xfs_log_item
*item
;
516 item
= list_first_entry(&cil
->xc_cil
,
517 struct xfs_log_item
, li_cil
);
518 list_del_init(&item
->li_cil
);
520 ctx
->lv_chain
= item
->li_lv
;
522 lv
->lv_next
= item
->li_lv
;
525 num_iovecs
+= lv
->lv_niovecs
;
529 * initialise the new context and attach it to the CIL. Then attach
530 * the current context to the CIL committing lsit so it can be found
531 * during log forces to extract the commit lsn of the sequence that
532 * needs to be forced.
534 INIT_LIST_HEAD(&new_ctx
->committing
);
535 INIT_LIST_HEAD(&new_ctx
->busy_extents
);
536 new_ctx
->sequence
= ctx
->sequence
+ 1;
538 cil
->xc_ctx
= new_ctx
;
541 * The switch is now done, so we can drop the context lock and move out
542 * of a shared context. We can't just go straight to the commit record,
543 * though - we need to synchronise with previous and future commits so
544 * that the commit records are correctly ordered in the log to ensure
545 * that we process items during log IO completion in the correct order.
547 * For example, if we get an EFI in one checkpoint and the EFD in the
548 * next (e.g. due to log forces), we do not want the checkpoint with
549 * the EFD to be committed before the checkpoint with the EFI. Hence
550 * we must strictly order the commit records of the checkpoints so
551 * that: a) the checkpoint callbacks are attached to the iclogs in the
552 * correct order; and b) the checkpoints are replayed in correct order
555 * Hence we need to add this context to the committing context list so
556 * that higher sequences will wait for us to write out a commit record
559 * xfs_log_force_lsn requires us to mirror the new sequence into the cil
560 * structure atomically with the addition of this sequence to the
561 * committing list. This also ensures that we can do unlocked checks
562 * against the current sequence in log forces without risking
563 * deferencing a freed context pointer.
565 spin_lock(&cil
->xc_push_lock
);
566 cil
->xc_current_sequence
= new_ctx
->sequence
;
567 spin_unlock(&cil
->xc_push_lock
);
568 up_write(&cil
->xc_ctx_lock
);
571 * Build a checkpoint transaction header and write it to the log to
572 * begin the transaction. We need to account for the space used by the
573 * transaction header here as it is not accounted for in xlog_write().
575 * The LSN we need to pass to the log items on transaction commit is
576 * the LSN reported by the first log vector write. If we use the commit
577 * record lsn then we can move the tail beyond the grant write head.
580 thdr
.th_magic
= XFS_TRANS_HEADER_MAGIC
;
581 thdr
.th_type
= XFS_TRANS_CHECKPOINT
;
582 thdr
.th_tid
= tic
->t_tid
;
583 thdr
.th_num_items
= num_iovecs
;
585 lhdr
.i_len
= sizeof(xfs_trans_header_t
);
586 lhdr
.i_type
= XLOG_REG_TYPE_TRANSHDR
;
587 tic
->t_curr_res
-= lhdr
.i_len
+ sizeof(xlog_op_header_t
);
589 lvhdr
.lv_niovecs
= 1;
590 lvhdr
.lv_iovecp
= &lhdr
;
591 lvhdr
.lv_next
= ctx
->lv_chain
;
593 error
= xlog_write(log
, &lvhdr
, tic
, &ctx
->start_lsn
, NULL
, 0);
595 goto out_abort_free_ticket
;
598 * now that we've written the checkpoint into the log, strictly
599 * order the commit records so replay will get them in the right order.
602 spin_lock(&cil
->xc_push_lock
);
603 list_for_each_entry(new_ctx
, &cil
->xc_committing
, committing
) {
605 * Avoid getting stuck in this loop because we were woken by the
606 * shutdown, but then went back to sleep once already in the
609 if (XLOG_FORCED_SHUTDOWN(log
)) {
610 spin_unlock(&cil
->xc_push_lock
);
611 goto out_abort_free_ticket
;
615 * Higher sequences will wait for this one so skip them.
616 * Don't wait for our own sequence, either.
618 if (new_ctx
->sequence
>= ctx
->sequence
)
620 if (!new_ctx
->commit_lsn
) {
622 * It is still being pushed! Wait for the push to
623 * complete, then start again from the beginning.
625 xlog_wait(&cil
->xc_commit_wait
, &cil
->xc_push_lock
);
629 spin_unlock(&cil
->xc_push_lock
);
631 /* xfs_log_done always frees the ticket on error. */
632 commit_lsn
= xfs_log_done(log
->l_mp
, tic
, &commit_iclog
, false);
633 if (commit_lsn
== -1)
636 /* attach all the transactions w/ busy extents to iclog */
637 ctx
->log_cb
.cb_func
= xlog_cil_committed
;
638 ctx
->log_cb
.cb_arg
= ctx
;
639 error
= xfs_log_notify(log
->l_mp
, commit_iclog
, &ctx
->log_cb
);
644 * now the checkpoint commit is complete and we've attached the
645 * callbacks to the iclog we can assign the commit LSN to the context
646 * and wake up anyone who is waiting for the commit to complete.
648 spin_lock(&cil
->xc_push_lock
);
649 ctx
->commit_lsn
= commit_lsn
;
650 wake_up_all(&cil
->xc_commit_wait
);
651 spin_unlock(&cil
->xc_push_lock
);
653 /* release the hounds! */
654 return xfs_log_release_iclog(log
->l_mp
, commit_iclog
);
657 up_write(&cil
->xc_ctx_lock
);
658 xfs_log_ticket_put(new_ctx
->ticket
);
662 out_abort_free_ticket
:
663 xfs_log_ticket_put(tic
);
665 xlog_cil_committed(ctx
, XFS_LI_ABORTED
);
671 struct work_struct
*work
)
673 struct xfs_cil
*cil
= container_of(work
, struct xfs_cil
,
675 xlog_cil_push(cil
->xc_log
);
679 * We need to push CIL every so often so we don't cache more than we can fit in
680 * the log. The limit really is that a checkpoint can't be more than half the
681 * log (the current checkpoint is not allowed to overwrite the previous
682 * checkpoint), but commit latency and memory usage limit this to a smaller
686 xlog_cil_push_background(
689 struct xfs_cil
*cil
= log
->l_cilp
;
692 * The cil won't be empty because we are called while holding the
693 * context lock so whatever we added to the CIL will still be there
695 ASSERT(!list_empty(&cil
->xc_cil
));
698 * don't do a background push if we haven't used up all the
699 * space available yet.
701 if (cil
->xc_ctx
->space_used
< XLOG_CIL_SPACE_LIMIT(log
))
704 spin_lock(&cil
->xc_push_lock
);
705 if (cil
->xc_push_seq
< cil
->xc_current_sequence
) {
706 cil
->xc_push_seq
= cil
->xc_current_sequence
;
707 queue_work(log
->l_mp
->m_cil_workqueue
, &cil
->xc_push_work
);
709 spin_unlock(&cil
->xc_push_lock
);
714 * xlog_cil_push_now() is used to trigger an immediate CIL push to the sequence
715 * number that is passed. When it returns, the work will be queued for
716 * @push_seq, but it won't be completed. The caller is expected to do any
717 * waiting for push_seq to complete if it is required.
724 struct xfs_cil
*cil
= log
->l_cilp
;
729 ASSERT(push_seq
&& push_seq
<= cil
->xc_current_sequence
);
731 /* start on any pending background push to minimise wait time on it */
732 flush_work(&cil
->xc_push_work
);
735 * If the CIL is empty or we've already pushed the sequence then
736 * there's no work we need to do.
738 spin_lock(&cil
->xc_push_lock
);
739 if (list_empty(&cil
->xc_cil
) || push_seq
<= cil
->xc_push_seq
) {
740 spin_unlock(&cil
->xc_push_lock
);
744 cil
->xc_push_seq
= push_seq
;
745 queue_work(log
->l_mp
->m_cil_workqueue
, &cil
->xc_push_work
);
746 spin_unlock(&cil
->xc_push_lock
);
753 struct xfs_cil
*cil
= log
->l_cilp
;
756 spin_lock(&cil
->xc_push_lock
);
757 if (list_empty(&cil
->xc_cil
))
759 spin_unlock(&cil
->xc_push_lock
);
764 * Commit a transaction with the given vector to the Committed Item List.
766 * To do this, we need to format the item, pin it in memory if required and
767 * account for the space used by the transaction. Once we have done that we
768 * need to release the unused reservation for the transaction, attach the
769 * transaction to the checkpoint context so we carry the busy extents through
770 * to checkpoint completion, and then unlock all the items in the transaction.
772 * Called with the context lock already held in read mode to lock out
773 * background commit, returns without it held once background commits are
778 struct xfs_mount
*mp
,
779 struct xfs_trans
*tp
,
780 xfs_lsn_t
*commit_lsn
,
783 struct xlog
*log
= mp
->m_log
;
784 struct xfs_cil
*cil
= log
->l_cilp
;
786 /* lock out background commit */
787 down_read(&cil
->xc_ctx_lock
);
789 xlog_cil_insert_items(log
, tp
);
791 /* check we didn't blow the reservation */
792 if (tp
->t_ticket
->t_curr_res
< 0)
793 xlog_print_tic_res(mp
, tp
->t_ticket
);
795 tp
->t_commit_lsn
= cil
->xc_ctx
->sequence
;
797 *commit_lsn
= tp
->t_commit_lsn
;
799 xfs_log_done(mp
, tp
->t_ticket
, NULL
, regrant
);
800 xfs_trans_unreserve_and_mod_sb(tp
);
803 * Once all the items of the transaction have been copied to the CIL,
804 * the items can be unlocked and freed.
806 * This needs to be done before we drop the CIL context lock because we
807 * have to update state in the log items and unlock them before they go
808 * to disk. If we don't, then the CIL checkpoint can race with us and
809 * we can run checkpoint completion before we've updated and unlocked
810 * the log items. This affects (at least) processing of stale buffers,
813 xfs_trans_free_items(tp
, tp
->t_commit_lsn
, false);
815 xlog_cil_push_background(log
);
817 up_read(&cil
->xc_ctx_lock
);
821 * Conditionally push the CIL based on the sequence passed in.
823 * We only need to push if we haven't already pushed the sequence
824 * number given. Hence the only time we will trigger a push here is
825 * if the push sequence is the same as the current context.
827 * We return the current commit lsn to allow the callers to determine if a
828 * iclog flush is necessary following this call.
835 struct xfs_cil
*cil
= log
->l_cilp
;
836 struct xfs_cil_ctx
*ctx
;
837 xfs_lsn_t commit_lsn
= NULLCOMMITLSN
;
839 ASSERT(sequence
<= cil
->xc_current_sequence
);
842 * check to see if we need to force out the current context.
843 * xlog_cil_push() handles racing pushes for the same sequence,
844 * so no need to deal with it here.
847 xlog_cil_push_now(log
, sequence
);
850 * See if we can find a previous sequence still committing.
851 * We need to wait for all previous sequence commits to complete
852 * before allowing the force of push_seq to go ahead. Hence block
853 * on commits for those as well.
855 spin_lock(&cil
->xc_push_lock
);
856 list_for_each_entry(ctx
, &cil
->xc_committing
, committing
) {
858 * Avoid getting stuck in this loop because we were woken by the
859 * shutdown, but then went back to sleep once already in the
862 if (XLOG_FORCED_SHUTDOWN(log
))
864 if (ctx
->sequence
> sequence
)
866 if (!ctx
->commit_lsn
) {
868 * It is still being pushed! Wait for the push to
869 * complete, then start again from the beginning.
871 xlog_wait(&cil
->xc_commit_wait
, &cil
->xc_push_lock
);
874 if (ctx
->sequence
!= sequence
)
877 commit_lsn
= ctx
->commit_lsn
;
881 * The call to xlog_cil_push_now() executes the push in the background.
882 * Hence by the time we have got here it our sequence may not have been
883 * pushed yet. This is true if the current sequence still matches the
884 * push sequence after the above wait loop and the CIL still contains
885 * dirty objects. This is guaranteed by the push code first adding the
886 * context to the committing list before emptying the CIL.
888 * Hence if we don't find the context in the committing list and the
889 * current sequence number is unchanged then the CIL contents are
890 * significant. If the CIL is empty, if means there was nothing to push
891 * and that means there is nothing to wait for. If the CIL is not empty,
892 * it means we haven't yet started the push, because if it had started
893 * we would have found the context on the committing list.
895 if (sequence
== cil
->xc_current_sequence
&&
896 !list_empty(&cil
->xc_cil
)) {
897 spin_unlock(&cil
->xc_push_lock
);
901 spin_unlock(&cil
->xc_push_lock
);
905 * We detected a shutdown in progress. We need to trigger the log force
906 * to pass through it's iclog state machine error handling, even though
907 * we are already in a shutdown state. Hence we can't return
908 * NULLCOMMITLSN here as that has special meaning to log forces (i.e.
909 * LSN is already stable), so we return a zero LSN instead.
912 spin_unlock(&cil
->xc_push_lock
);
917 * Check if the current log item was first committed in this sequence.
918 * We can't rely on just the log item being in the CIL, we have to check
919 * the recorded commit sequence number.
921 * Note: for this to be used in a non-racy manner, it has to be called with
922 * CIL flushing locked out. As a result, it should only be used during the
923 * transaction commit process when deciding what to format into the item.
926 xfs_log_item_in_current_chkpt(
927 struct xfs_log_item
*lip
)
929 struct xfs_cil_ctx
*ctx
;
931 if (list_empty(&lip
->li_cil
))
934 ctx
= lip
->li_mountp
->m_log
->l_cilp
->xc_ctx
;
937 * li_seq is written on the first commit of a log item to record the
938 * first checkpoint it is written to. Hence if it is different to the
939 * current sequence, we're in a new checkpoint.
941 if (XFS_LSN_CMP(lip
->li_seq
, ctx
->sequence
) != 0)
947 * Perform initial CIL structure initialisation.
954 struct xfs_cil_ctx
*ctx
;
956 cil
= kmem_zalloc(sizeof(*cil
), KM_SLEEP
|KM_MAYFAIL
);
960 ctx
= kmem_zalloc(sizeof(*ctx
), KM_SLEEP
|KM_MAYFAIL
);
966 INIT_WORK(&cil
->xc_push_work
, xlog_cil_push_work
);
967 INIT_LIST_HEAD(&cil
->xc_cil
);
968 INIT_LIST_HEAD(&cil
->xc_committing
);
969 spin_lock_init(&cil
->xc_cil_lock
);
970 spin_lock_init(&cil
->xc_push_lock
);
971 init_rwsem(&cil
->xc_ctx_lock
);
972 init_waitqueue_head(&cil
->xc_commit_wait
);
974 INIT_LIST_HEAD(&ctx
->committing
);
975 INIT_LIST_HEAD(&ctx
->busy_extents
);
979 cil
->xc_current_sequence
= ctx
->sequence
;
990 if (log
->l_cilp
->xc_ctx
) {
991 if (log
->l_cilp
->xc_ctx
->ticket
)
992 xfs_log_ticket_put(log
->l_cilp
->xc_ctx
->ticket
);
993 kmem_free(log
->l_cilp
->xc_ctx
);
996 ASSERT(list_empty(&log
->l_cilp
->xc_cil
));
997 kmem_free(log
->l_cilp
);
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