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_bit.h"
13#include "xfs_mount.h"
14#include "xfs_trans.h"
15#include "xfs_trans_priv.h"
16#include "xfs_buf_item.h"
17#include "xfs_inode.h"
18#include "xfs_inode_item.h"
19#include "xfs_quota.h"
20#include "xfs_dquot_item.h"
21#include "xfs_dquot.h"
22#include "xfs_trace.h"
23#include "xfs_log.h"
24#include "xfs_log_priv.h"
25
26
27struct kmem_cache *xfs_buf_item_cache;
28
29static inline struct xfs_buf_log_item *BUF_ITEM(struct xfs_log_item *lip)
30{
31 return container_of(lip, struct xfs_buf_log_item, bli_item);
32}
33
34/* Is this log iovec plausibly large enough to contain the buffer log format? */
35bool
36xfs_buf_log_check_iovec(
37 struct xfs_log_iovec *iovec)
38{
39 struct xfs_buf_log_format *blfp = iovec->i_addr;
40 char *bmp_end;
41 char *item_end;
42
43 if (offsetof(struct xfs_buf_log_format, blf_data_map) > iovec->i_len)
44 return false;
45
46 item_end = (char *)iovec->i_addr + iovec->i_len;
47 bmp_end = (char *)&blfp->blf_data_map[blfp->blf_map_size];
48 return bmp_end <= item_end;
49}
50
51static inline int
52xfs_buf_log_format_size(
53 struct xfs_buf_log_format *blfp)
54{
55 return offsetof(struct xfs_buf_log_format, blf_data_map) +
56 (blfp->blf_map_size * sizeof(blfp->blf_data_map[0]));
57}
58
59static inline bool
60xfs_buf_item_straddle(
61 struct xfs_buf *bp,
62 uint offset,
63 int first_bit,
64 int nbits)
65{
66 void *first, *last;
67
68 first = xfs_buf_offset(bp, offset + (first_bit << XFS_BLF_SHIFT));
69 last = xfs_buf_offset(bp,
70 offset + ((first_bit + nbits) << XFS_BLF_SHIFT));
71
72 if (last - first != nbits * XFS_BLF_CHUNK)
73 return true;
74 return false;
75}
76
77/*
78 * Return the number of log iovecs and space needed to log the given buf log
79 * item segment.
80 *
81 * It calculates this as 1 iovec for the buf log format structure and 1 for each
82 * stretch of non-contiguous chunks to be logged. Contiguous chunks are logged
83 * in a single iovec.
84 */
85STATIC void
86xfs_buf_item_size_segment(
87 struct xfs_buf_log_item *bip,
88 struct xfs_buf_log_format *blfp,
89 uint offset,
90 int *nvecs,
91 int *nbytes)
92{
93 struct xfs_buf *bp = bip->bli_buf;
94 int first_bit;
95 int nbits;
96 int next_bit;
97 int last_bit;
98
99 first_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size, 0);
100 if (first_bit == -1)
101 return;
102
103 (*nvecs)++;
104 *nbytes += xfs_buf_log_format_size(blfp);
105
106 do {
107 nbits = xfs_contig_bits(blfp->blf_data_map,
108 blfp->blf_map_size, first_bit);
109 ASSERT(nbits > 0);
110
111 /*
112 * Straddling a page is rare because we don't log contiguous
113 * chunks of unmapped buffers anywhere.
114 */
115 if (nbits > 1 &&
116 xfs_buf_item_straddle(bp, offset, first_bit, nbits))
117 goto slow_scan;
118
119 (*nvecs)++;
120 *nbytes += nbits * XFS_BLF_CHUNK;
121
122 /*
123 * This takes the bit number to start looking from and
124 * returns the next set bit from there. It returns -1
125 * if there are no more bits set or the start bit is
126 * beyond the end of the bitmap.
127 */
128 first_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size,
129 (uint)first_bit + nbits + 1);
130 } while (first_bit != -1);
131
132 return;
133
134slow_scan:
135 /* Count the first bit we jumped out of the above loop from */
136 (*nvecs)++;
137 *nbytes += XFS_BLF_CHUNK;
138 last_bit = first_bit;
139 while (last_bit != -1) {
140 /*
141 * This takes the bit number to start looking from and
142 * returns the next set bit from there. It returns -1
143 * if there are no more bits set or the start bit is
144 * beyond the end of the bitmap.
145 */
146 next_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size,
147 last_bit + 1);
148 /*
149 * If we run out of bits, leave the loop,
150 * else if we find a new set of bits bump the number of vecs,
151 * else keep scanning the current set of bits.
152 */
153 if (next_bit == -1) {
154 break;
155 } else if (next_bit != last_bit + 1 ||
156 xfs_buf_item_straddle(bp, offset, first_bit, nbits)) {
157 last_bit = next_bit;
158 first_bit = next_bit;
159 (*nvecs)++;
160 nbits = 1;
161 } else {
162 last_bit++;
163 nbits++;
164 }
165 *nbytes += XFS_BLF_CHUNK;
166 }
167}
168
169/*
170 * Return the number of log iovecs and space needed to log the given buf log
171 * item.
172 *
173 * Discontiguous buffers need a format structure per region that is being
174 * logged. This makes the changes in the buffer appear to log recovery as though
175 * they came from separate buffers, just like would occur if multiple buffers
176 * were used instead of a single discontiguous buffer. This enables
177 * discontiguous buffers to be in-memory constructs, completely transparent to
178 * what ends up on disk.
179 *
180 * If the XFS_BLI_STALE flag has been set, then log nothing but the buf log
181 * format structures. If the item has previously been logged and has dirty
182 * regions, we do not relog them in stale buffers. This has the effect of
183 * reducing the size of the relogged item by the amount of dirty data tracked
184 * by the log item. This can result in the committing transaction reducing the
185 * amount of space being consumed by the CIL.
186 */
187STATIC void
188xfs_buf_item_size(
189 struct xfs_log_item *lip,
190 int *nvecs,
191 int *nbytes)
192{
193 struct xfs_buf_log_item *bip = BUF_ITEM(lip);
194 struct xfs_buf *bp = bip->bli_buf;
195 int i;
196 int bytes;
197 uint offset = 0;
198
199 ASSERT(atomic_read(&bip->bli_refcount) > 0);
200 if (bip->bli_flags & XFS_BLI_STALE) {
201 /*
202 * The buffer is stale, so all we need to log is the buf log
203 * format structure with the cancel flag in it as we are never
204 * going to replay the changes tracked in the log item.
205 */
206 trace_xfs_buf_item_size_stale(bip);
207 ASSERT(bip->__bli_format.blf_flags & XFS_BLF_CANCEL);
208 *nvecs += bip->bli_format_count;
209 for (i = 0; i < bip->bli_format_count; i++) {
210 *nbytes += xfs_buf_log_format_size(&bip->bli_formats[i]);
211 }
212 return;
213 }
214
215 ASSERT(bip->bli_flags & XFS_BLI_LOGGED);
216
217 if (bip->bli_flags & XFS_BLI_ORDERED) {
218 /*
219 * The buffer has been logged just to order it. It is not being
220 * included in the transaction commit, so no vectors are used at
221 * all.
222 */
223 trace_xfs_buf_item_size_ordered(bip);
224 *nvecs = XFS_LOG_VEC_ORDERED;
225 return;
226 }
227
228 /*
229 * The vector count is based on the number of buffer vectors we have
230 * dirty bits in. This will only be greater than one when we have a
231 * compound buffer with more than one segment dirty. Hence for compound
232 * buffers we need to track which segment the dirty bits correspond to,
233 * and when we move from one segment to the next increment the vector
234 * count for the extra buf log format structure that will need to be
235 * written.
236 */
237 bytes = 0;
238 for (i = 0; i < bip->bli_format_count; i++) {
239 xfs_buf_item_size_segment(bip, &bip->bli_formats[i], offset,
240 nvecs, &bytes);
241 offset += BBTOB(bp->b_maps[i].bm_len);
242 }
243
244 /*
245 * Round up the buffer size required to minimise the number of memory
246 * allocations that need to be done as this item grows when relogged by
247 * repeated modifications.
248 */
249 *nbytes = round_up(bytes, 512);
250 trace_xfs_buf_item_size(bip);
251}
252
253static inline void
254xfs_buf_item_copy_iovec(
255 struct xfs_log_vec *lv,
256 struct xfs_log_iovec **vecp,
257 struct xfs_buf *bp,
258 uint offset,
259 int first_bit,
260 uint nbits)
261{
262 offset += first_bit * XFS_BLF_CHUNK;
263 xlog_copy_iovec(lv, vecp, XLOG_REG_TYPE_BCHUNK,
264 xfs_buf_offset(bp, offset),
265 nbits * XFS_BLF_CHUNK);
266}
267
268static void
269xfs_buf_item_format_segment(
270 struct xfs_buf_log_item *bip,
271 struct xfs_log_vec *lv,
272 struct xfs_log_iovec **vecp,
273 uint offset,
274 struct xfs_buf_log_format *blfp)
275{
276 struct xfs_buf *bp = bip->bli_buf;
277 uint base_size;
278 int first_bit;
279 int last_bit;
280 int next_bit;
281 uint nbits;
282
283 /* copy the flags across from the base format item */
284 blfp->blf_flags = bip->__bli_format.blf_flags;
285
286 /*
287 * Base size is the actual size of the ondisk structure - it reflects
288 * the actual size of the dirty bitmap rather than the size of the in
289 * memory structure.
290 */
291 base_size = xfs_buf_log_format_size(blfp);
292
293 first_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size, 0);
294 if (!(bip->bli_flags & XFS_BLI_STALE) && first_bit == -1) {
295 /*
296 * If the map is not be dirty in the transaction, mark
297 * the size as zero and do not advance the vector pointer.
298 */
299 return;
300 }
301
302 blfp = xlog_copy_iovec(lv, vecp, XLOG_REG_TYPE_BFORMAT, blfp, base_size);
303 blfp->blf_size = 1;
304
305 if (bip->bli_flags & XFS_BLI_STALE) {
306 /*
307 * The buffer is stale, so all we need to log
308 * is the buf log format structure with the
309 * cancel flag in it.
310 */
311 trace_xfs_buf_item_format_stale(bip);
312 ASSERT(blfp->blf_flags & XFS_BLF_CANCEL);
313 return;
314 }
315
316
317 /*
318 * Fill in an iovec for each set of contiguous chunks.
319 */
320 do {
321 ASSERT(first_bit >= 0);
322 nbits = xfs_contig_bits(blfp->blf_data_map,
323 blfp->blf_map_size, first_bit);
324 ASSERT(nbits > 0);
325
326 /*
327 * Straddling a page is rare because we don't log contiguous
328 * chunks of unmapped buffers anywhere.
329 */
330 if (nbits > 1 &&
331 xfs_buf_item_straddle(bp, offset, first_bit, nbits))
332 goto slow_scan;
333
334 xfs_buf_item_copy_iovec(lv, vecp, bp, offset,
335 first_bit, nbits);
336 blfp->blf_size++;
337
338 /*
339 * This takes the bit number to start looking from and
340 * returns the next set bit from there. It returns -1
341 * if there are no more bits set or the start bit is
342 * beyond the end of the bitmap.
343 */
344 first_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size,
345 (uint)first_bit + nbits + 1);
346 } while (first_bit != -1);
347
348 return;
349
350slow_scan:
351 ASSERT(bp->b_addr == NULL);
352 last_bit = first_bit;
353 nbits = 1;
354 for (;;) {
355 /*
356 * This takes the bit number to start looking from and
357 * returns the next set bit from there. It returns -1
358 * if there are no more bits set or the start bit is
359 * beyond the end of the bitmap.
360 */
361 next_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size,
362 (uint)last_bit + 1);
363 /*
364 * If we run out of bits fill in the last iovec and get out of
365 * the loop. Else if we start a new set of bits then fill in
366 * the iovec for the series we were looking at and start
367 * counting the bits in the new one. Else we're still in the
368 * same set of bits so just keep counting and scanning.
369 */
370 if (next_bit == -1) {
371 xfs_buf_item_copy_iovec(lv, vecp, bp, offset,
372 first_bit, nbits);
373 blfp->blf_size++;
374 break;
375 } else if (next_bit != last_bit + 1 ||
376 xfs_buf_item_straddle(bp, offset, first_bit, nbits)) {
377 xfs_buf_item_copy_iovec(lv, vecp, bp, offset,
378 first_bit, nbits);
379 blfp->blf_size++;
380 first_bit = next_bit;
381 last_bit = next_bit;
382 nbits = 1;
383 } else {
384 last_bit++;
385 nbits++;
386 }
387 }
388}
389
390/*
391 * This is called to fill in the vector of log iovecs for the
392 * given log buf item. It fills the first entry with a buf log
393 * format structure, and the rest point to contiguous chunks
394 * within the buffer.
395 */
396STATIC void
397xfs_buf_item_format(
398 struct xfs_log_item *lip,
399 struct xfs_log_vec *lv)
400{
401 struct xfs_buf_log_item *bip = BUF_ITEM(lip);
402 struct xfs_buf *bp = bip->bli_buf;
403 struct xfs_log_iovec *vecp = NULL;
404 uint offset = 0;
405 int i;
406
407 ASSERT(atomic_read(&bip->bli_refcount) > 0);
408 ASSERT((bip->bli_flags & XFS_BLI_LOGGED) ||
409 (bip->bli_flags & XFS_BLI_STALE));
410 ASSERT((bip->bli_flags & XFS_BLI_STALE) ||
411 (xfs_blft_from_flags(&bip->__bli_format) > XFS_BLFT_UNKNOWN_BUF
412 && xfs_blft_from_flags(&bip->__bli_format) < XFS_BLFT_MAX_BUF));
413 ASSERT(!(bip->bli_flags & XFS_BLI_ORDERED) ||
414 (bip->bli_flags & XFS_BLI_STALE));
415
416
417 /*
418 * If it is an inode buffer, transfer the in-memory state to the
419 * format flags and clear the in-memory state.
420 *
421 * For buffer based inode allocation, we do not transfer
422 * this state if the inode buffer allocation has not yet been committed
423 * to the log as setting the XFS_BLI_INODE_BUF flag will prevent
424 * correct replay of the inode allocation.
425 *
426 * For icreate item based inode allocation, the buffers aren't written
427 * to the journal during allocation, and hence we should always tag the
428 * buffer as an inode buffer so that the correct unlinked list replay
429 * occurs during recovery.
430 */
431 if (bip->bli_flags & XFS_BLI_INODE_BUF) {
432 if (xfs_has_v3inodes(lip->li_log->l_mp) ||
433 !((bip->bli_flags & XFS_BLI_INODE_ALLOC_BUF) &&
434 xfs_log_item_in_current_chkpt(lip)))
435 bip->__bli_format.blf_flags |= XFS_BLF_INODE_BUF;
436 bip->bli_flags &= ~XFS_BLI_INODE_BUF;
437 }
438
439 for (i = 0; i < bip->bli_format_count; i++) {
440 xfs_buf_item_format_segment(bip, lv, &vecp, offset,
441 &bip->bli_formats[i]);
442 offset += BBTOB(bp->b_maps[i].bm_len);
443 }
444
445 /*
446 * Check to make sure everything is consistent.
447 */
448 trace_xfs_buf_item_format(bip);
449}
450
451/*
452 * This is called to pin the buffer associated with the buf log item in memory
453 * so it cannot be written out.
454 *
455 * We take a reference to the buffer log item here so that the BLI life cycle
456 * extends at least until the buffer is unpinned via xfs_buf_item_unpin() and
457 * inserted into the AIL.
458 *
459 * We also need to take a reference to the buffer itself as the BLI unpin
460 * processing requires accessing the buffer after the BLI has dropped the final
461 * BLI reference. See xfs_buf_item_unpin() for an explanation.
462 * If unpins race to drop the final BLI reference and only the
463 * BLI owns a reference to the buffer, then the loser of the race can have the
464 * buffer fgreed from under it (e.g. on shutdown). Taking a buffer reference per
465 * pin count ensures the life cycle of the buffer extends for as
466 * long as we hold the buffer pin reference in xfs_buf_item_unpin().
467 */
468STATIC void
469xfs_buf_item_pin(
470 struct xfs_log_item *lip)
471{
472 struct xfs_buf_log_item *bip = BUF_ITEM(lip);
473
474 ASSERT(atomic_read(&bip->bli_refcount) > 0);
475 ASSERT((bip->bli_flags & XFS_BLI_LOGGED) ||
476 (bip->bli_flags & XFS_BLI_ORDERED) ||
477 (bip->bli_flags & XFS_BLI_STALE));
478
479 trace_xfs_buf_item_pin(bip);
480
481 xfs_buf_hold(bp: bip->bli_buf);
482 atomic_inc(v: &bip->bli_refcount);
483 atomic_inc(v: &bip->bli_buf->b_pin_count);
484}
485
486/*
487 * This is called to unpin the buffer associated with the buf log item which was
488 * previously pinned with a call to xfs_buf_item_pin(). We enter this function
489 * with a buffer pin count, a buffer reference and a BLI reference.
490 *
491 * We must drop the BLI reference before we unpin the buffer because the AIL
492 * doesn't acquire a BLI reference whenever it accesses it. Therefore if the
493 * refcount drops to zero, the bli could still be AIL resident and the buffer
494 * submitted for I/O at any point before we return. This can result in IO
495 * completion freeing the buffer while we are still trying to access it here.
496 * This race condition can also occur in shutdown situations where we abort and
497 * unpin buffers from contexts other that journal IO completion.
498 *
499 * Hence we have to hold a buffer reference per pin count to ensure that the
500 * buffer cannot be freed until we have finished processing the unpin operation.
501 * The reference is taken in xfs_buf_item_pin(), and we must hold it until we
502 * are done processing the buffer state. In the case of an abort (remove =
503 * true) then we re-use the current pin reference as the IO reference we hand
504 * off to IO failure handling.
505 */
506STATIC void
507xfs_buf_item_unpin(
508 struct xfs_log_item *lip,
509 int remove)
510{
511 struct xfs_buf_log_item *bip = BUF_ITEM(lip);
512 struct xfs_buf *bp = bip->bli_buf;
513 int stale = bip->bli_flags & XFS_BLI_STALE;
514 int freed;
515
516 ASSERT(bp->b_log_item == bip);
517 ASSERT(atomic_read(&bip->bli_refcount) > 0);
518
519 trace_xfs_buf_item_unpin(bip);
520
521 freed = atomic_dec_and_test(v: &bip->bli_refcount);
522 if (atomic_dec_and_test(v: &bp->b_pin_count))
523 wake_up_all(&bp->b_waiters);
524
525 /*
526 * Nothing to do but drop the buffer pin reference if the BLI is
527 * still active.
528 */
529 if (!freed) {
530 xfs_buf_rele(bp);
531 return;
532 }
533
534 if (stale) {
535 ASSERT(bip->bli_flags & XFS_BLI_STALE);
536 ASSERT(xfs_buf_islocked(bp));
537 ASSERT(bp->b_flags & XBF_STALE);
538 ASSERT(bip->__bli_format.blf_flags & XFS_BLF_CANCEL);
539 ASSERT(list_empty(&lip->li_trans));
540 ASSERT(!bp->b_transp);
541
542 trace_xfs_buf_item_unpin_stale(bip);
543
544 /*
545 * The buffer has been locked and referenced since it was marked
546 * stale so we own both lock and reference exclusively here. We
547 * do not need the pin reference any more, so drop it now so
548 * that we only have one reference to drop once item completion
549 * processing is complete.
550 */
551 xfs_buf_rele(bp);
552
553 /*
554 * If we get called here because of an IO error, we may or may
555 * not have the item on the AIL. xfs_trans_ail_delete() will
556 * take care of that situation. xfs_trans_ail_delete() drops
557 * the AIL lock.
558 */
559 if (bip->bli_flags & XFS_BLI_STALE_INODE) {
560 xfs_buf_item_done(bp);
561 xfs_buf_inode_iodone(bp);
562 ASSERT(list_empty(&bp->b_li_list));
563 } else {
564 xfs_trans_ail_delete(lip, SHUTDOWN_LOG_IO_ERROR);
565 xfs_buf_item_relse(bp);
566 ASSERT(bp->b_log_item == NULL);
567 }
568 xfs_buf_relse(bp);
569 return;
570 }
571
572 if (remove) {
573 /*
574 * We need to simulate an async IO failures here to ensure that
575 * the correct error completion is run on this buffer. This
576 * requires a reference to the buffer and for the buffer to be
577 * locked. We can safely pass ownership of the pin reference to
578 * the IO to ensure that nothing can free the buffer while we
579 * wait for the lock and then run the IO failure completion.
580 */
581 xfs_buf_lock(bp);
582 bp->b_flags |= XBF_ASYNC;
583 xfs_buf_ioend_fail(bp);
584 return;
585 }
586
587 /*
588 * BLI has no more active references - it will be moved to the AIL to
589 * manage the remaining BLI/buffer life cycle. There is nothing left for
590 * us to do here so drop the pin reference to the buffer.
591 */
592 xfs_buf_rele(bp);
593}
594
595STATIC uint
596xfs_buf_item_push(
597 struct xfs_log_item *lip,
598 struct list_head *buffer_list)
599{
600 struct xfs_buf_log_item *bip = BUF_ITEM(lip);
601 struct xfs_buf *bp = bip->bli_buf;
602 uint rval = XFS_ITEM_SUCCESS;
603
604 if (xfs_buf_ispinned(bp))
605 return XFS_ITEM_PINNED;
606 if (!xfs_buf_trylock(bp)) {
607 /*
608 * If we have just raced with a buffer being pinned and it has
609 * been marked stale, we could end up stalling until someone else
610 * issues a log force to unpin the stale buffer. Check for the
611 * race condition here so xfsaild recognizes the buffer is pinned
612 * and queues a log force to move it along.
613 */
614 if (xfs_buf_ispinned(bp))
615 return XFS_ITEM_PINNED;
616 return XFS_ITEM_LOCKED;
617 }
618
619 ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
620
621 trace_xfs_buf_item_push(bip);
622
623 /* has a previous flush failed due to IO errors? */
624 if (bp->b_flags & XBF_WRITE_FAIL) {
625 xfs_buf_alert_ratelimited(bp, rlmsg: "XFS: Failing async write",
626 fmt: "Failing async write on buffer block 0x%llx. Retrying async write.",
627 (long long)xfs_buf_daddr(bp));
628 }
629
630 if (!xfs_buf_delwri_queue(bp, buffer_list))
631 rval = XFS_ITEM_FLUSHING;
632 xfs_buf_unlock(bp);
633 return rval;
634}
635
636/*
637 * Drop the buffer log item refcount and take appropriate action. This helper
638 * determines whether the bli must be freed or not, since a decrement to zero
639 * does not necessarily mean the bli is unused.
640 *
641 * Return true if the bli is freed, false otherwise.
642 */
643bool
644xfs_buf_item_put(
645 struct xfs_buf_log_item *bip)
646{
647 struct xfs_log_item *lip = &bip->bli_item;
648 bool aborted;
649 bool dirty;
650
651 /* drop the bli ref and return if it wasn't the last one */
652 if (!atomic_dec_and_test(v: &bip->bli_refcount))
653 return false;
654
655 /*
656 * We dropped the last ref and must free the item if clean or aborted.
657 * If the bli is dirty and non-aborted, the buffer was clean in the
658 * transaction but still awaiting writeback from previous changes. In
659 * that case, the bli is freed on buffer writeback completion.
660 */
661 aborted = test_bit(XFS_LI_ABORTED, &lip->li_flags) ||
662 xlog_is_shutdown(log: lip->li_log);
663 dirty = bip->bli_flags & XFS_BLI_DIRTY;
664 if (dirty && !aborted)
665 return false;
666
667 /*
668 * The bli is aborted or clean. An aborted item may be in the AIL
669 * regardless of dirty state. For example, consider an aborted
670 * transaction that invalidated a dirty bli and cleared the dirty
671 * state.
672 */
673 if (aborted)
674 xfs_trans_ail_delete(lip, shutdown_type: 0);
675 xfs_buf_item_relse(bip->bli_buf);
676 return true;
677}
678
679/*
680 * Release the buffer associated with the buf log item. If there is no dirty
681 * logged data associated with the buffer recorded in the buf log item, then
682 * free the buf log item and remove the reference to it in the buffer.
683 *
684 * This call ignores the recursion count. It is only called when the buffer
685 * should REALLY be unlocked, regardless of the recursion count.
686 *
687 * We unconditionally drop the transaction's reference to the log item. If the
688 * item was logged, then another reference was taken when it was pinned, so we
689 * can safely drop the transaction reference now. This also allows us to avoid
690 * potential races with the unpin code freeing the bli by not referencing the
691 * bli after we've dropped the reference count.
692 *
693 * If the XFS_BLI_HOLD flag is set in the buf log item, then free the log item
694 * if necessary but do not unlock the buffer. This is for support of
695 * xfs_trans_bhold(). Make sure the XFS_BLI_HOLD field is cleared if we don't
696 * free the item.
697 */
698STATIC void
699xfs_buf_item_release(
700 struct xfs_log_item *lip)
701{
702 struct xfs_buf_log_item *bip = BUF_ITEM(lip);
703 struct xfs_buf *bp = bip->bli_buf;
704 bool released;
705 bool hold = bip->bli_flags & XFS_BLI_HOLD;
706 bool stale = bip->bli_flags & XFS_BLI_STALE;
707#if defined(DEBUG) || defined(XFS_WARN)
708 bool ordered = bip->bli_flags & XFS_BLI_ORDERED;
709 bool dirty = bip->bli_flags & XFS_BLI_DIRTY;
710 bool aborted = test_bit(XFS_LI_ABORTED,
711 &lip->li_flags);
712#endif
713
714 trace_xfs_buf_item_release(bip);
715
716 /*
717 * The bli dirty state should match whether the blf has logged segments
718 * except for ordered buffers, where only the bli should be dirty.
719 */
720 ASSERT((!ordered && dirty == xfs_buf_item_dirty_format(bip)) ||
721 (ordered && dirty && !xfs_buf_item_dirty_format(bip)));
722 ASSERT(!stale || (bip->__bli_format.blf_flags & XFS_BLF_CANCEL));
723
724 /*
725 * Clear the buffer's association with this transaction and
726 * per-transaction state from the bli, which has been copied above.
727 */
728 bp->b_transp = NULL;
729 bip->bli_flags &= ~(XFS_BLI_LOGGED | XFS_BLI_HOLD | XFS_BLI_ORDERED);
730
731 /*
732 * Unref the item and unlock the buffer unless held or stale. Stale
733 * buffers remain locked until final unpin unless the bli is freed by
734 * the unref call. The latter implies shutdown because buffer
735 * invalidation dirties the bli and transaction.
736 */
737 released = xfs_buf_item_put(bip);
738 if (hold || (stale && !released))
739 return;
740 ASSERT(!stale || aborted);
741 xfs_buf_relse(bp);
742}
743
744STATIC void
745xfs_buf_item_committing(
746 struct xfs_log_item *lip,
747 xfs_csn_t seq)
748{
749 return xfs_buf_item_release(lip);
750}
751
752/*
753 * This is called to find out where the oldest active copy of the
754 * buf log item in the on disk log resides now that the last log
755 * write of it completed at the given lsn.
756 * We always re-log all the dirty data in a buffer, so usually the
757 * latest copy in the on disk log is the only one that matters. For
758 * those cases we simply return the given lsn.
759 *
760 * The one exception to this is for buffers full of newly allocated
761 * inodes. These buffers are only relogged with the XFS_BLI_INODE_BUF
762 * flag set, indicating that only the di_next_unlinked fields from the
763 * inodes in the buffers will be replayed during recovery. If the
764 * original newly allocated inode images have not yet been flushed
765 * when the buffer is so relogged, then we need to make sure that we
766 * keep the old images in the 'active' portion of the log. We do this
767 * by returning the original lsn of that transaction here rather than
768 * the current one.
769 */
770STATIC xfs_lsn_t
771xfs_buf_item_committed(
772 struct xfs_log_item *lip,
773 xfs_lsn_t lsn)
774{
775 struct xfs_buf_log_item *bip = BUF_ITEM(lip);
776
777 trace_xfs_buf_item_committed(bip);
778
779 if ((bip->bli_flags & XFS_BLI_INODE_ALLOC_BUF) && lip->li_lsn != 0)
780 return lip->li_lsn;
781 return lsn;
782}
783
784static const struct xfs_item_ops xfs_buf_item_ops = {
785 .iop_size = xfs_buf_item_size,
786 .iop_format = xfs_buf_item_format,
787 .iop_pin = xfs_buf_item_pin,
788 .iop_unpin = xfs_buf_item_unpin,
789 .iop_release = xfs_buf_item_release,
790 .iop_committing = xfs_buf_item_committing,
791 .iop_committed = xfs_buf_item_committed,
792 .iop_push = xfs_buf_item_push,
793};
794
795STATIC void
796xfs_buf_item_get_format(
797 struct xfs_buf_log_item *bip,
798 int count)
799{
800 ASSERT(bip->bli_formats == NULL);
801 bip->bli_format_count = count;
802
803 if (count == 1) {
804 bip->bli_formats = &bip->__bli_format;
805 return;
806 }
807
808 bip->bli_formats = kzalloc(count * sizeof(struct xfs_buf_log_format),
809 GFP_KERNEL | __GFP_NOFAIL);
810}
811
812STATIC void
813xfs_buf_item_free_format(
814 struct xfs_buf_log_item *bip)
815{
816 if (bip->bli_formats != &bip->__bli_format) {
817 kfree(objp: bip->bli_formats);
818 bip->bli_formats = NULL;
819 }
820}
821
822/*
823 * Allocate a new buf log item to go with the given buffer.
824 * Set the buffer's b_log_item field to point to the new
825 * buf log item.
826 */
827int
828xfs_buf_item_init(
829 struct xfs_buf *bp,
830 struct xfs_mount *mp)
831{
832 struct xfs_buf_log_item *bip = bp->b_log_item;
833 int chunks;
834 int map_size;
835 int i;
836
837 /*
838 * Check to see if there is already a buf log item for
839 * this buffer. If we do already have one, there is
840 * nothing to do here so return.
841 */
842 ASSERT(bp->b_mount == mp);
843 if (bip) {
844 ASSERT(bip->bli_item.li_type == XFS_LI_BUF);
845 ASSERT(!bp->b_transp);
846 ASSERT(bip->bli_buf == bp);
847 return 0;
848 }
849
850 bip = kmem_cache_zalloc(k: xfs_buf_item_cache, GFP_KERNEL | __GFP_NOFAIL);
851 xfs_log_item_init(mp, &bip->bli_item, XFS_LI_BUF, &xfs_buf_item_ops);
852 bip->bli_buf = bp;
853
854 /*
855 * chunks is the number of XFS_BLF_CHUNK size pieces the buffer
856 * can be divided into. Make sure not to truncate any pieces.
857 * map_size is the size of the bitmap needed to describe the
858 * chunks of the buffer.
859 *
860 * Discontiguous buffer support follows the layout of the underlying
861 * buffer. This makes the implementation as simple as possible.
862 */
863 xfs_buf_item_get_format(bip, count: bp->b_map_count);
864
865 for (i = 0; i < bip->bli_format_count; i++) {
866 chunks = DIV_ROUND_UP(BBTOB(bp->b_maps[i].bm_len),
867 XFS_BLF_CHUNK);
868 map_size = DIV_ROUND_UP(chunks, NBWORD);
869
870 if (map_size > XFS_BLF_DATAMAP_SIZE) {
871 kmem_cache_free(s: xfs_buf_item_cache, objp: bip);
872 xfs_err(mp,
873 "buffer item dirty bitmap (%u uints) too small to reflect %u bytes!",
874 map_size,
875 BBTOB(bp->b_maps[i].bm_len));
876 return -EFSCORRUPTED;
877 }
878
879 bip->bli_formats[i].blf_type = XFS_LI_BUF;
880 bip->bli_formats[i].blf_blkno = bp->b_maps[i].bm_bn;
881 bip->bli_formats[i].blf_len = bp->b_maps[i].bm_len;
882 bip->bli_formats[i].blf_map_size = map_size;
883 }
884
885 bp->b_log_item = bip;
886 xfs_buf_hold(bp);
887 return 0;
888}
889
890
891/*
892 * Mark bytes first through last inclusive as dirty in the buf
893 * item's bitmap.
894 */
895static void
896xfs_buf_item_log_segment(
897 uint first,
898 uint last,
899 uint *map)
900{
901 uint first_bit;
902 uint last_bit;
903 uint bits_to_set;
904 uint bits_set;
905 uint word_num;
906 uint *wordp;
907 uint bit;
908 uint end_bit;
909 uint mask;
910
911 ASSERT(first < XFS_BLF_DATAMAP_SIZE * XFS_BLF_CHUNK * NBWORD);
912 ASSERT(last < XFS_BLF_DATAMAP_SIZE * XFS_BLF_CHUNK * NBWORD);
913
914 /*
915 * Convert byte offsets to bit numbers.
916 */
917 first_bit = first >> XFS_BLF_SHIFT;
918 last_bit = last >> XFS_BLF_SHIFT;
919
920 /*
921 * Calculate the total number of bits to be set.
922 */
923 bits_to_set = last_bit - first_bit + 1;
924
925 /*
926 * Get a pointer to the first word in the bitmap
927 * to set a bit in.
928 */
929 word_num = first_bit >> BIT_TO_WORD_SHIFT;
930 wordp = &map[word_num];
931
932 /*
933 * Calculate the starting bit in the first word.
934 */
935 bit = first_bit & (uint)(NBWORD - 1);
936
937 /*
938 * First set any bits in the first word of our range.
939 * If it starts at bit 0 of the word, it will be
940 * set below rather than here. That is what the variable
941 * bit tells us. The variable bits_set tracks the number
942 * of bits that have been set so far. End_bit is the number
943 * of the last bit to be set in this word plus one.
944 */
945 if (bit) {
946 end_bit = min(bit + bits_to_set, (uint)NBWORD);
947 mask = ((1U << (end_bit - bit)) - 1) << bit;
948 *wordp |= mask;
949 wordp++;
950 bits_set = end_bit - bit;
951 } else {
952 bits_set = 0;
953 }
954
955 /*
956 * Now set bits a whole word at a time that are between
957 * first_bit and last_bit.
958 */
959 while ((bits_to_set - bits_set) >= NBWORD) {
960 *wordp = 0xffffffff;
961 bits_set += NBWORD;
962 wordp++;
963 }
964
965 /*
966 * Finally, set any bits left to be set in one last partial word.
967 */
968 end_bit = bits_to_set - bits_set;
969 if (end_bit) {
970 mask = (1U << end_bit) - 1;
971 *wordp |= mask;
972 }
973}
974
975/*
976 * Mark bytes first through last inclusive as dirty in the buf
977 * item's bitmap.
978 */
979void
980xfs_buf_item_log(
981 struct xfs_buf_log_item *bip,
982 uint first,
983 uint last)
984{
985 int i;
986 uint start;
987 uint end;
988 struct xfs_buf *bp = bip->bli_buf;
989
990 /*
991 * walk each buffer segment and mark them dirty appropriately.
992 */
993 start = 0;
994 for (i = 0; i < bip->bli_format_count; i++) {
995 if (start > last)
996 break;
997 end = start + BBTOB(bp->b_maps[i].bm_len) - 1;
998
999 /* skip to the map that includes the first byte to log */
1000 if (first > end) {
1001 start += BBTOB(bp->b_maps[i].bm_len);
1002 continue;
1003 }
1004
1005 /*
1006 * Trim the range to this segment and mark it in the bitmap.
1007 * Note that we must convert buffer offsets to segment relative
1008 * offsets (e.g., the first byte of each segment is byte 0 of
1009 * that segment).
1010 */
1011 if (first < start)
1012 first = start;
1013 if (end > last)
1014 end = last;
1015 xfs_buf_item_log_segment(first - start, end - start,
1016 &bip->bli_formats[i].blf_data_map[0]);
1017
1018 start += BBTOB(bp->b_maps[i].bm_len);
1019 }
1020}
1021
1022
1023/*
1024 * Return true if the buffer has any ranges logged/dirtied by a transaction,
1025 * false otherwise.
1026 */
1027bool
1028xfs_buf_item_dirty_format(
1029 struct xfs_buf_log_item *bip)
1030{
1031 int i;
1032
1033 for (i = 0; i < bip->bli_format_count; i++) {
1034 if (!xfs_bitmap_empty(bip->bli_formats[i].blf_data_map,
1035 bip->bli_formats[i].blf_map_size))
1036 return true;
1037 }
1038
1039 return false;
1040}
1041
1042STATIC void
1043xfs_buf_item_free(
1044 struct xfs_buf_log_item *bip)
1045{
1046 xfs_buf_item_free_format(bip);
1047 kvfree(addr: bip->bli_item.li_lv_shadow);
1048 kmem_cache_free(s: xfs_buf_item_cache, objp: bip);
1049}
1050
1051/*
1052 * xfs_buf_item_relse() is called when the buf log item is no longer needed.
1053 */
1054void
1055xfs_buf_item_relse(
1056 struct xfs_buf *bp)
1057{
1058 struct xfs_buf_log_item *bip = bp->b_log_item;
1059
1060 trace_xfs_buf_item_relse(bp, _RET_IP_);
1061 ASSERT(!test_bit(XFS_LI_IN_AIL, &bip->bli_item.li_flags));
1062
1063 if (atomic_read(v: &bip->bli_refcount))
1064 return;
1065 bp->b_log_item = NULL;
1066 xfs_buf_rele(bp);
1067 xfs_buf_item_free(bip);
1068}
1069
1070void
1071xfs_buf_item_done(
1072 struct xfs_buf *bp)
1073{
1074 /*
1075 * If we are forcibly shutting down, this may well be off the AIL
1076 * already. That's because we simulate the log-committed callbacks to
1077 * unpin these buffers. Or we may never have put this item on AIL
1078 * because of the transaction was aborted forcibly.
1079 * xfs_trans_ail_delete() takes care of these.
1080 *
1081 * Either way, AIL is useless if we're forcing a shutdown.
1082 *
1083 * Note that log recovery writes might have buffer items that are not on
1084 * the AIL even when the file system is not shut down.
1085 */
1086 xfs_trans_ail_delete(lip: &bp->b_log_item->bli_item,
1087 shutdown_type: (bp->b_flags & _XBF_LOGRECOVERY) ? 0 :
1088 SHUTDOWN_CORRUPT_INCORE);
1089 xfs_buf_item_relse(bp);
1090}
1091

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