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1 /*
2 * Copyright (c) 2010 Red Hat, Inc. All Rights Reserved.
3 *
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.
7 *
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.
12 *
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
16 */
17
18 #include "xfs.h"
19 #include "xfs_fs.h"
20 #include "xfs_types.h"
21 #include "xfs_bit.h"
22 #include "xfs_log.h"
23 #include "xfs_inum.h"
24 #include "xfs_trans.h"
25 #include "xfs_trans_priv.h"
26 #include "xfs_log_priv.h"
27 #include "xfs_sb.h"
28 #include "xfs_ag.h"
29 #include "xfs_mount.h"
30 #include "xfs_error.h"
31 #include "xfs_alloc.h"
32
33 /*
34 * Perform initial CIL structure initialisation. If the CIL is not
35 * enabled in this filesystem, ensure the log->l_cilp is null so
36 * we can check this conditional to determine if we are doing delayed
37 * logging or not.
38 */
39 int
40 xlog_cil_init(
41 struct log *log)
42 {
43 struct xfs_cil *cil;
44 struct xfs_cil_ctx *ctx;
45
46 log->l_cilp = NULL;
47 if (!(log->l_mp->m_flags & XFS_MOUNT_DELAYLOG))
48 return 0;
49
50 cil = kmem_zalloc(sizeof(*cil), KM_SLEEP|KM_MAYFAIL);
51 if (!cil)
52 return ENOMEM;
53
54 ctx = kmem_zalloc(sizeof(*ctx), KM_SLEEP|KM_MAYFAIL);
55 if (!ctx) {
56 kmem_free(cil);
57 return ENOMEM;
58 }
59
60 INIT_LIST_HEAD(&cil->xc_cil);
61 INIT_LIST_HEAD(&cil->xc_committing);
62 spin_lock_init(&cil->xc_cil_lock);
63 init_rwsem(&cil->xc_ctx_lock);
64 init_waitqueue_head(&cil->xc_commit_wait);
65
66 INIT_LIST_HEAD(&ctx->committing);
67 INIT_LIST_HEAD(&ctx->busy_extents);
68 ctx->sequence = 1;
69 ctx->cil = cil;
70 cil->xc_ctx = ctx;
71 cil->xc_current_sequence = ctx->sequence;
72
73 cil->xc_log = log;
74 log->l_cilp = cil;
75 return 0;
76 }
77
78 void
79 xlog_cil_destroy(
80 struct log *log)
81 {
82 if (!log->l_cilp)
83 return;
84
85 if (log->l_cilp->xc_ctx) {
86 if (log->l_cilp->xc_ctx->ticket)
87 xfs_log_ticket_put(log->l_cilp->xc_ctx->ticket);
88 kmem_free(log->l_cilp->xc_ctx);
89 }
90
91 ASSERT(list_empty(&log->l_cilp->xc_cil));
92 kmem_free(log->l_cilp);
93 }
94
95 /*
96 * Allocate a new ticket. Failing to get a new ticket makes it really hard to
97 * recover, so we don't allow failure here. Also, we allocate in a context that
98 * we don't want to be issuing transactions from, so we need to tell the
99 * allocation code this as well.
100 *
101 * We don't reserve any space for the ticket - we are going to steal whatever
102 * space we require from transactions as they commit. To ensure we reserve all
103 * the space required, we need to set the current reservation of the ticket to
104 * zero so that we know to steal the initial transaction overhead from the
105 * first transaction commit.
106 */
107 static struct xlog_ticket *
108 xlog_cil_ticket_alloc(
109 struct log *log)
110 {
111 struct xlog_ticket *tic;
112
113 tic = xlog_ticket_alloc(log, 0, 1, XFS_TRANSACTION, 0,
114 KM_SLEEP|KM_NOFS);
115 tic->t_trans_type = XFS_TRANS_CHECKPOINT;
116
117 /*
118 * set the current reservation to zero so we know to steal the basic
119 * transaction overhead reservation from the first transaction commit.
120 */
121 tic->t_curr_res = 0;
122 return tic;
123 }
124
125 /*
126 * After the first stage of log recovery is done, we know where the head and
127 * tail of the log are. We need this log initialisation done before we can
128 * initialise the first CIL checkpoint context.
129 *
130 * Here we allocate a log ticket to track space usage during a CIL push. This
131 * ticket is passed to xlog_write() directly so that we don't slowly leak log
132 * space by failing to account for space used by log headers and additional
133 * region headers for split regions.
134 */
135 void
136 xlog_cil_init_post_recovery(
137 struct log *log)
138 {
139 if (!log->l_cilp)
140 return;
141
142 log->l_cilp->xc_ctx->ticket = xlog_cil_ticket_alloc(log);
143 log->l_cilp->xc_ctx->sequence = 1;
144 log->l_cilp->xc_ctx->commit_lsn = xlog_assign_lsn(log->l_curr_cycle,
145 log->l_curr_block);
146 }
147
148 /*
149 * Format log item into a flat buffers
150 *
151 * For delayed logging, we need to hold a formatted buffer containing all the
152 * changes on the log item. This enables us to relog the item in memory and
153 * write it out asynchronously without needing to relock the object that was
154 * modified at the time it gets written into the iclog.
155 *
156 * This function builds a vector for the changes in each log item in the
157 * transaction. It then works out the length of the buffer needed for each log
158 * item, allocates them and formats the vector for the item into the buffer.
159 * The buffer is then attached to the log item are then inserted into the
160 * Committed Item List for tracking until the next checkpoint is written out.
161 *
162 * We don't set up region headers during this process; we simply copy the
163 * regions into the flat buffer. We can do this because we still have to do a
164 * formatting step to write the regions into the iclog buffer. Writing the
165 * ophdrs during the iclog write means that we can support splitting large
166 * regions across iclog boundares without needing a change in the format of the
167 * item/region encapsulation.
168 *
169 * Hence what we need to do now is change the rewrite the vector array to point
170 * to the copied region inside the buffer we just allocated. This allows us to
171 * format the regions into the iclog as though they are being formatted
172 * directly out of the objects themselves.
173 */
174 static void
175 xlog_cil_format_items(
176 struct log *log,
177 struct xfs_log_vec *log_vector)
178 {
179 struct xfs_log_vec *lv;
180
181 ASSERT(log_vector);
182 for (lv = log_vector; lv; lv = lv->lv_next) {
183 void *ptr;
184 int index;
185 int len = 0;
186
187 /* build the vector array and calculate it's length */
188 IOP_FORMAT(lv->lv_item, lv->lv_iovecp);
189 for (index = 0; index < lv->lv_niovecs; index++)
190 len += lv->lv_iovecp[index].i_len;
191
192 lv->lv_buf_len = len;
193 lv->lv_buf = kmem_alloc(lv->lv_buf_len, KM_SLEEP|KM_NOFS);
194 ptr = lv->lv_buf;
195
196 for (index = 0; index < lv->lv_niovecs; index++) {
197 struct xfs_log_iovec *vec = &lv->lv_iovecp[index];
198
199 memcpy(ptr, vec->i_addr, vec->i_len);
200 vec->i_addr = ptr;
201 ptr += vec->i_len;
202 }
203 ASSERT(ptr == lv->lv_buf + lv->lv_buf_len);
204 }
205 }
206
207 /*
208 * Prepare the log item for insertion into the CIL. Calculate the difference in
209 * log space and vectors it will consume, and if it is a new item pin it as
210 * well.
211 */
212 STATIC void
213 xfs_cil_prepare_item(
214 struct log *log,
215 struct xfs_log_vec *lv,
216 int *len,
217 int *diff_iovecs)
218 {
219 struct xfs_log_vec *old = lv->lv_item->li_lv;
220
221 if (old) {
222 /* existing lv on log item, space used is a delta */
223 ASSERT(!list_empty(&lv->lv_item->li_cil));
224 ASSERT(old->lv_buf && old->lv_buf_len && old->lv_niovecs);
225
226 *len += lv->lv_buf_len - old->lv_buf_len;
227 *diff_iovecs += lv->lv_niovecs - old->lv_niovecs;
228 kmem_free(old->lv_buf);
229 kmem_free(old);
230 } else {
231 /* new lv, must pin the log item */
232 ASSERT(!lv->lv_item->li_lv);
233 ASSERT(list_empty(&lv->lv_item->li_cil));
234
235 *len += lv->lv_buf_len;
236 *diff_iovecs += lv->lv_niovecs;
237 IOP_PIN(lv->lv_item);
238
239 }
240
241 /* attach new log vector to log item */
242 lv->lv_item->li_lv = lv;
243
244 /*
245 * If this is the first time the item is being committed to the
246 * CIL, store the sequence number on the log item so we can
247 * tell in future commits whether this is the first checkpoint
248 * the item is being committed into.
249 */
250 if (!lv->lv_item->li_seq)
251 lv->lv_item->li_seq = log->l_cilp->xc_ctx->sequence;
252 }
253
254 /*
255 * Insert the log items into the CIL and calculate the difference in space
256 * consumed by the item. Add the space to the checkpoint ticket and calculate
257 * if the change requires additional log metadata. If it does, take that space
258 * as well. Remove the amount of space we addded to the checkpoint ticket from
259 * the current transaction ticket so that the accounting works out correctly.
260 */
261 static void
262 xlog_cil_insert_items(
263 struct log *log,
264 struct xfs_log_vec *log_vector,
265 struct xlog_ticket *ticket)
266 {
267 struct xfs_cil *cil = log->l_cilp;
268 struct xfs_cil_ctx *ctx = cil->xc_ctx;
269 struct xfs_log_vec *lv;
270 int len = 0;
271 int diff_iovecs = 0;
272 int iclog_space;
273
274 ASSERT(log_vector);
275
276 /*
277 * Do all the accounting aggregation and switching of log vectors
278 * around in a separate loop to the insertion of items into the CIL.
279 * Then we can do a separate loop to update the CIL within a single
280 * lock/unlock pair. This reduces the number of round trips on the CIL
281 * lock from O(nr_logvectors) to O(1) and greatly reduces the overall
282 * hold time for the transaction commit.
283 *
284 * If this is the first time the item is being placed into the CIL in
285 * this context, pin it so it can't be written to disk until the CIL is
286 * flushed to the iclog and the iclog written to disk.
287 *
288 * We can do this safely because the context can't checkpoint until we
289 * are done so it doesn't matter exactly how we update the CIL.
290 */
291 for (lv = log_vector; lv; lv = lv->lv_next)
292 xfs_cil_prepare_item(log, lv, &len, &diff_iovecs);
293
294 /* account for space used by new iovec headers */
295 len += diff_iovecs * sizeof(xlog_op_header_t);
296
297 spin_lock(&cil->xc_cil_lock);
298
299 /* move the items to the tail of the CIL */
300 for (lv = log_vector; lv; lv = lv->lv_next)
301 list_move_tail(&lv->lv_item->li_cil, &cil->xc_cil);
302
303 ctx->nvecs += diff_iovecs;
304
305 /*
306 * Now transfer enough transaction reservation to the context ticket
307 * for the checkpoint. The context ticket is special - the unit
308 * reservation has to grow as well as the current reservation as we
309 * steal from tickets so we can correctly determine the space used
310 * during the transaction commit.
311 */
312 if (ctx->ticket->t_curr_res == 0) {
313 /* first commit in checkpoint, steal the header reservation */
314 ASSERT(ticket->t_curr_res >= ctx->ticket->t_unit_res + len);
315 ctx->ticket->t_curr_res = ctx->ticket->t_unit_res;
316 ticket->t_curr_res -= ctx->ticket->t_unit_res;
317 }
318
319 /* do we need space for more log record headers? */
320 iclog_space = log->l_iclog_size - log->l_iclog_hsize;
321 if (len > 0 && (ctx->space_used / iclog_space !=
322 (ctx->space_used + len) / iclog_space)) {
323 int hdrs;
324
325 hdrs = (len + iclog_space - 1) / iclog_space;
326 /* need to take into account split region headers, too */
327 hdrs *= log->l_iclog_hsize + sizeof(struct xlog_op_header);
328 ctx->ticket->t_unit_res += hdrs;
329 ctx->ticket->t_curr_res += hdrs;
330 ticket->t_curr_res -= hdrs;
331 ASSERT(ticket->t_curr_res >= len);
332 }
333 ticket->t_curr_res -= len;
334 ctx->space_used += len;
335
336 spin_unlock(&cil->xc_cil_lock);
337 }
338
339 static void
340 xlog_cil_free_logvec(
341 struct xfs_log_vec *log_vector)
342 {
343 struct xfs_log_vec *lv;
344
345 for (lv = log_vector; lv; ) {
346 struct xfs_log_vec *next = lv->lv_next;
347 kmem_free(lv->lv_buf);
348 kmem_free(lv);
349 lv = next;
350 }
351 }
352
353 /*
354 * Mark all items committed and clear busy extents. We free the log vector
355 * chains in a separate pass so that we unpin the log items as quickly as
356 * possible.
357 */
358 static void
359 xlog_cil_committed(
360 void *args,
361 int abort)
362 {
363 struct xfs_cil_ctx *ctx = args;
364 struct xfs_busy_extent *busyp, *n;
365
366 xfs_trans_committed_bulk(ctx->cil->xc_log->l_ailp, ctx->lv_chain,
367 ctx->start_lsn, abort);
368
369 list_for_each_entry_safe(busyp, n, &ctx->busy_extents, list)
370 xfs_alloc_busy_clear(ctx->cil->xc_log->l_mp, busyp);
371
372 spin_lock(&ctx->cil->xc_cil_lock);
373 list_del(&ctx->committing);
374 spin_unlock(&ctx->cil->xc_cil_lock);
375
376 xlog_cil_free_logvec(ctx->lv_chain);
377 kmem_free(ctx);
378 }
379
380 /*
381 * Push the Committed Item List to the log. If @push_seq flag is zero, then it
382 * is a background flush and so we can chose to ignore it. Otherwise, if the
383 * current sequence is the same as @push_seq we need to do a flush. If
384 * @push_seq is less than the current sequence, then it has already been
385 * flushed and we don't need to do anything - the caller will wait for it to
386 * complete if necessary.
387 *
388 * @push_seq is a value rather than a flag because that allows us to do an
389 * unlocked check of the sequence number for a match. Hence we can allows log
390 * forces to run racily and not issue pushes for the same sequence twice. If we
391 * get a race between multiple pushes for the same sequence they will block on
392 * the first one and then abort, hence avoiding needless pushes.
393 */
394 STATIC int
395 xlog_cil_push(
396 struct log *log,
397 xfs_lsn_t push_seq)
398 {
399 struct xfs_cil *cil = log->l_cilp;
400 struct xfs_log_vec *lv;
401 struct xfs_cil_ctx *ctx;
402 struct xfs_cil_ctx *new_ctx;
403 struct xlog_in_core *commit_iclog;
404 struct xlog_ticket *tic;
405 int num_lv;
406 int num_iovecs;
407 int len;
408 int error = 0;
409 struct xfs_trans_header thdr;
410 struct xfs_log_iovec lhdr;
411 struct xfs_log_vec lvhdr = { NULL };
412 xfs_lsn_t commit_lsn;
413
414 if (!cil)
415 return 0;
416
417 ASSERT(!push_seq || push_seq <= cil->xc_ctx->sequence);
418
419 new_ctx = kmem_zalloc(sizeof(*new_ctx), KM_SLEEP|KM_NOFS);
420 new_ctx->ticket = xlog_cil_ticket_alloc(log);
421
422 /*
423 * Lock out transaction commit, but don't block for background pushes
424 * unless we are well over the CIL space limit. See the definition of
425 * XLOG_CIL_HARD_SPACE_LIMIT() for the full explanation of the logic
426 * used here.
427 */
428 if (!down_write_trylock(&cil->xc_ctx_lock)) {
429 if (!push_seq &&
430 cil->xc_ctx->space_used < XLOG_CIL_HARD_SPACE_LIMIT(log))
431 goto out_free_ticket;
432 down_write(&cil->xc_ctx_lock);
433 }
434 ctx = cil->xc_ctx;
435
436 /* check if we've anything to push */
437 if (list_empty(&cil->xc_cil))
438 goto out_skip;
439
440 /* check for spurious background flush */
441 if (!push_seq && cil->xc_ctx->space_used < XLOG_CIL_SPACE_LIMIT(log))
442 goto out_skip;
443
444 /* check for a previously pushed seqeunce */
445 if (push_seq && push_seq < cil->xc_ctx->sequence)
446 goto out_skip;
447
448 /*
449 * pull all the log vectors off the items in the CIL, and
450 * remove the items from the CIL. We don't need the CIL lock
451 * here because it's only needed on the transaction commit
452 * side which is currently locked out by the flush lock.
453 */
454 lv = NULL;
455 num_lv = 0;
456 num_iovecs = 0;
457 len = 0;
458 while (!list_empty(&cil->xc_cil)) {
459 struct xfs_log_item *item;
460 int i;
461
462 item = list_first_entry(&cil->xc_cil,
463 struct xfs_log_item, li_cil);
464 list_del_init(&item->li_cil);
465 if (!ctx->lv_chain)
466 ctx->lv_chain = item->li_lv;
467 else
468 lv->lv_next = item->li_lv;
469 lv = item->li_lv;
470 item->li_lv = NULL;
471
472 num_lv++;
473 num_iovecs += lv->lv_niovecs;
474 for (i = 0; i < lv->lv_niovecs; i++)
475 len += lv->lv_iovecp[i].i_len;
476 }
477
478 /*
479 * initialise the new context and attach it to the CIL. Then attach
480 * the current context to the CIL committing lsit so it can be found
481 * during log forces to extract the commit lsn of the sequence that
482 * needs to be forced.
483 */
484 INIT_LIST_HEAD(&new_ctx->committing);
485 INIT_LIST_HEAD(&new_ctx->busy_extents);
486 new_ctx->sequence = ctx->sequence + 1;
487 new_ctx->cil = cil;
488 cil->xc_ctx = new_ctx;
489
490 /*
491 * mirror the new sequence into the cil structure so that we can do
492 * unlocked checks against the current sequence in log forces without
493 * risking deferencing a freed context pointer.
494 */
495 cil->xc_current_sequence = new_ctx->sequence;
496
497 /*
498 * The switch is now done, so we can drop the context lock and move out
499 * of a shared context. We can't just go straight to the commit record,
500 * though - we need to synchronise with previous and future commits so
501 * that the commit records are correctly ordered in the log to ensure
502 * that we process items during log IO completion in the correct order.
503 *
504 * For example, if we get an EFI in one checkpoint and the EFD in the
505 * next (e.g. due to log forces), we do not want the checkpoint with
506 * the EFD to be committed before the checkpoint with the EFI. Hence
507 * we must strictly order the commit records of the checkpoints so
508 * that: a) the checkpoint callbacks are attached to the iclogs in the
509 * correct order; and b) the checkpoints are replayed in correct order
510 * in log recovery.
511 *
512 * Hence we need to add this context to the committing context list so
513 * that higher sequences will wait for us to write out a commit record
514 * before they do.
515 */
516 spin_lock(&cil->xc_cil_lock);
517 list_add(&ctx->committing, &cil->xc_committing);
518 spin_unlock(&cil->xc_cil_lock);
519 up_write(&cil->xc_ctx_lock);
520
521 /*
522 * Build a checkpoint transaction header and write it to the log to
523 * begin the transaction. We need to account for the space used by the
524 * transaction header here as it is not accounted for in xlog_write().
525 *
526 * The LSN we need to pass to the log items on transaction commit is
527 * the LSN reported by the first log vector write. If we use the commit
528 * record lsn then we can move the tail beyond the grant write head.
529 */
530 tic = ctx->ticket;
531 thdr.th_magic = XFS_TRANS_HEADER_MAGIC;
532 thdr.th_type = XFS_TRANS_CHECKPOINT;
533 thdr.th_tid = tic->t_tid;
534 thdr.th_num_items = num_iovecs;
535 lhdr.i_addr = &thdr;
536 lhdr.i_len = sizeof(xfs_trans_header_t);
537 lhdr.i_type = XLOG_REG_TYPE_TRANSHDR;
538 tic->t_curr_res -= lhdr.i_len + sizeof(xlog_op_header_t);
539
540 lvhdr.lv_niovecs = 1;
541 lvhdr.lv_iovecp = &lhdr;
542 lvhdr.lv_next = ctx->lv_chain;
543
544 error = xlog_write(log, &lvhdr, tic, &ctx->start_lsn, NULL, 0);
545 if (error)
546 goto out_abort_free_ticket;
547
548 /*
549 * now that we've written the checkpoint into the log, strictly
550 * order the commit records so replay will get them in the right order.
551 */
552 restart:
553 spin_lock(&cil->xc_cil_lock);
554 list_for_each_entry(new_ctx, &cil->xc_committing, committing) {
555 /*
556 * Higher sequences will wait for this one so skip them.
557 * Don't wait for own own sequence, either.
558 */
559 if (new_ctx->sequence >= ctx->sequence)
560 continue;
561 if (!new_ctx->commit_lsn) {
562 /*
563 * It is still being pushed! Wait for the push to
564 * complete, then start again from the beginning.
565 */
566 xlog_wait(&cil->xc_commit_wait, &cil->xc_cil_lock);
567 goto restart;
568 }
569 }
570 spin_unlock(&cil->xc_cil_lock);
571
572 /* xfs_log_done always frees the ticket on error. */
573 commit_lsn = xfs_log_done(log->l_mp, tic, &commit_iclog, 0);
574 if (commit_lsn == -1)
575 goto out_abort;
576
577 /* attach all the transactions w/ busy extents to iclog */
578 ctx->log_cb.cb_func = xlog_cil_committed;
579 ctx->log_cb.cb_arg = ctx;
580 error = xfs_log_notify(log->l_mp, commit_iclog, &ctx->log_cb);
581 if (error)
582 goto out_abort;
583
584 /*
585 * now the checkpoint commit is complete and we've attached the
586 * callbacks to the iclog we can assign the commit LSN to the context
587 * and wake up anyone who is waiting for the commit to complete.
588 */
589 spin_lock(&cil->xc_cil_lock);
590 ctx->commit_lsn = commit_lsn;
591 wake_up_all(&cil->xc_commit_wait);
592 spin_unlock(&cil->xc_cil_lock);
593
594 /* release the hounds! */
595 return xfs_log_release_iclog(log->l_mp, commit_iclog);
596
597 out_skip:
598 up_write(&cil->xc_ctx_lock);
599 out_free_ticket:
600 xfs_log_ticket_put(new_ctx->ticket);
601 kmem_free(new_ctx);
602 return 0;
603
604 out_abort_free_ticket:
605 xfs_log_ticket_put(tic);
606 out_abort:
607 xlog_cil_committed(ctx, XFS_LI_ABORTED);
608 return XFS_ERROR(EIO);
609 }
610
611 /*
612 * Commit a transaction with the given vector to the Committed Item List.
613 *
614 * To do this, we need to format the item, pin it in memory if required and
615 * account for the space used by the transaction. Once we have done that we
616 * need to release the unused reservation for the transaction, attach the
617 * transaction to the checkpoint context so we carry the busy extents through
618 * to checkpoint completion, and then unlock all the items in the transaction.
619 *
620 * For more specific information about the order of operations in
621 * xfs_log_commit_cil() please refer to the comments in
622 * xfs_trans_commit_iclog().
623 *
624 * Called with the context lock already held in read mode to lock out
625 * background commit, returns without it held once background commits are
626 * allowed again.
627 */
628 void
629 xfs_log_commit_cil(
630 struct xfs_mount *mp,
631 struct xfs_trans *tp,
632 struct xfs_log_vec *log_vector,
633 xfs_lsn_t *commit_lsn,
634 int flags)
635 {
636 struct log *log = mp->m_log;
637 int log_flags = 0;
638 int push = 0;
639
640 if (flags & XFS_TRANS_RELEASE_LOG_RES)
641 log_flags = XFS_LOG_REL_PERM_RESERV;
642
643 /*
644 * do all the hard work of formatting items (including memory
645 * allocation) outside the CIL context lock. This prevents stalling CIL
646 * pushes when we are low on memory and a transaction commit spends a
647 * lot of time in memory reclaim.
648 */
649 xlog_cil_format_items(log, log_vector);
650
651 /* lock out background commit */
652 down_read(&log->l_cilp->xc_ctx_lock);
653 if (commit_lsn)
654 *commit_lsn = log->l_cilp->xc_ctx->sequence;
655
656 xlog_cil_insert_items(log, log_vector, tp->t_ticket);
657
658 /* check we didn't blow the reservation */
659 if (tp->t_ticket->t_curr_res < 0)
660 xlog_print_tic_res(log->l_mp, tp->t_ticket);
661
662 /* attach the transaction to the CIL if it has any busy extents */
663 if (!list_empty(&tp->t_busy)) {
664 spin_lock(&log->l_cilp->xc_cil_lock);
665 list_splice_init(&tp->t_busy,
666 &log->l_cilp->xc_ctx->busy_extents);
667 spin_unlock(&log->l_cilp->xc_cil_lock);
668 }
669
670 tp->t_commit_lsn = *commit_lsn;
671 xfs_log_done(mp, tp->t_ticket, NULL, log_flags);
672 xfs_trans_unreserve_and_mod_sb(tp);
673
674 /*
675 * Once all the items of the transaction have been copied to the CIL,
676 * the items can be unlocked and freed.
677 *
678 * This needs to be done before we drop the CIL context lock because we
679 * have to update state in the log items and unlock them before they go
680 * to disk. If we don't, then the CIL checkpoint can race with us and
681 * we can run checkpoint completion before we've updated and unlocked
682 * the log items. This affects (at least) processing of stale buffers,
683 * inodes and EFIs.
684 */
685 xfs_trans_free_items(tp, *commit_lsn, 0);
686
687 /* check for background commit before unlock */
688 if (log->l_cilp->xc_ctx->space_used > XLOG_CIL_SPACE_LIMIT(log))
689 push = 1;
690
691 up_read(&log->l_cilp->xc_ctx_lock);
692
693 /*
694 * We need to push CIL every so often so we don't cache more than we
695 * can fit in the log. The limit really is that a checkpoint can't be
696 * more than half the log (the current checkpoint is not allowed to
697 * overwrite the previous checkpoint), but commit latency and memory
698 * usage limit this to a smaller size in most cases.
699 */
700 if (push)
701 xlog_cil_push(log, 0);
702 }
703
704 /*
705 * Conditionally push the CIL based on the sequence passed in.
706 *
707 * We only need to push if we haven't already pushed the sequence
708 * number given. Hence the only time we will trigger a push here is
709 * if the push sequence is the same as the current context.
710 *
711 * We return the current commit lsn to allow the callers to determine if a
712 * iclog flush is necessary following this call.
713 *
714 * XXX: Initially, just push the CIL unconditionally and return whatever
715 * commit lsn is there. It'll be empty, so this is broken for now.
716 */
717 xfs_lsn_t
718 xlog_cil_force_lsn(
719 struct log *log,
720 xfs_lsn_t sequence)
721 {
722 struct xfs_cil *cil = log->l_cilp;
723 struct xfs_cil_ctx *ctx;
724 xfs_lsn_t commit_lsn = NULLCOMMITLSN;
725
726 ASSERT(sequence <= cil->xc_current_sequence);
727
728 /*
729 * check to see if we need to force out the current context.
730 * xlog_cil_push() handles racing pushes for the same sequence,
731 * so no need to deal with it here.
732 */
733 if (sequence == cil->xc_current_sequence)
734 xlog_cil_push(log, sequence);
735
736 /*
737 * See if we can find a previous sequence still committing.
738 * We need to wait for all previous sequence commits to complete
739 * before allowing the force of push_seq to go ahead. Hence block
740 * on commits for those as well.
741 */
742 restart:
743 spin_lock(&cil->xc_cil_lock);
744 list_for_each_entry(ctx, &cil->xc_committing, committing) {
745 if (ctx->sequence > sequence)
746 continue;
747 if (!ctx->commit_lsn) {
748 /*
749 * It is still being pushed! Wait for the push to
750 * complete, then start again from the beginning.
751 */
752 xlog_wait(&cil->xc_commit_wait, &cil->xc_cil_lock);
753 goto restart;
754 }
755 if (ctx->sequence != sequence)
756 continue;
757 /* found it! */
758 commit_lsn = ctx->commit_lsn;
759 }
760 spin_unlock(&cil->xc_cil_lock);
761 return commit_lsn;
762 }
763
764 /*
765 * Check if the current log item was first committed in this sequence.
766 * We can't rely on just the log item being in the CIL, we have to check
767 * the recorded commit sequence number.
768 *
769 * Note: for this to be used in a non-racy manner, it has to be called with
770 * CIL flushing locked out. As a result, it should only be used during the
771 * transaction commit process when deciding what to format into the item.
772 */
773 bool
774 xfs_log_item_in_current_chkpt(
775 struct xfs_log_item *lip)
776 {
777 struct xfs_cil_ctx *ctx;
778
779 if (!(lip->li_mountp->m_flags & XFS_MOUNT_DELAYLOG))
780 return false;
781 if (list_empty(&lip->li_cil))
782 return false;
783
784 ctx = lip->li_mountp->m_log->l_cilp->xc_ctx;
785
786 /*
787 * li_seq is written on the first commit of a log item to record the
788 * first checkpoint it is written to. Hence if it is different to the
789 * current sequence, we're in a new checkpoint.
790 */
791 if (XFS_LSN_CMP(lip->li_seq, ctx->sequence) != 0)
792 return false;
793 return true;
794 }