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