Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * Copyright (c) 2000-2006 Silicon Graphics, Inc.
4 : * All Rights Reserved.
5 : */
6 : #include "xfs.h"
7 : #include <linux/backing-dev.h>
8 : #include <linux/dax.h>
9 :
10 : #include "xfs_shared.h"
11 : #include "xfs_format.h"
12 : #include "xfs_log_format.h"
13 : #include "xfs_trans_resv.h"
14 : #include "xfs_mount.h"
15 : #include "xfs_trace.h"
16 : #include "xfs_log.h"
17 : #include "xfs_log_recover.h"
18 : #include "xfs_log_priv.h"
19 : #include "xfs_trans.h"
20 : #include "xfs_buf_item.h"
21 : #include "xfs_errortag.h"
22 : #include "xfs_error.h"
23 : #include "xfs_ag.h"
24 :
25 : struct kmem_cache *xfs_buf_cache;
26 :
27 : /*
28 : * Locking orders
29 : *
30 : * xfs_buf_ioacct_inc:
31 : * xfs_buf_ioacct_dec:
32 : * b_sema (caller holds)
33 : * b_lock
34 : *
35 : * xfs_buf_stale:
36 : * b_sema (caller holds)
37 : * b_lock
38 : * lru_lock
39 : *
40 : * xfs_buf_rele:
41 : * b_lock
42 : * pag_buf_lock
43 : * lru_lock
44 : *
45 : * xfs_buftarg_drain_rele
46 : * lru_lock
47 : * b_lock (trylock due to inversion)
48 : *
49 : * xfs_buftarg_isolate
50 : * lru_lock
51 : * b_lock (trylock due to inversion)
52 : */
53 :
54 : static int __xfs_buf_submit(struct xfs_buf *bp, bool wait);
55 :
56 : static inline int
57 25901253 : xfs_buf_submit(
58 : struct xfs_buf *bp)
59 : {
60 25901253 : return __xfs_buf_submit(bp, !(bp->b_flags & XBF_ASYNC));
61 : }
62 :
63 : static inline int
64 : xfs_buf_is_vmapped(
65 : struct xfs_buf *bp)
66 : {
67 : /*
68 : * Return true if the buffer is vmapped.
69 : *
70 : * b_addr is null if the buffer is not mapped, but the code is clever
71 : * enough to know it doesn't have to map a single page, so the check has
72 : * to be both for b_addr and bp->b_page_count > 1.
73 : */
74 138446 : return bp->b_addr && bp->b_page_count > 1;
75 : }
76 :
77 : static inline int
78 : xfs_buf_vmap_len(
79 : struct xfs_buf *bp)
80 : {
81 : return (bp->b_page_count * PAGE_SIZE);
82 : }
83 :
84 : /*
85 : * Bump the I/O in flight count on the buftarg if we haven't yet done so for
86 : * this buffer. The count is incremented once per buffer (per hold cycle)
87 : * because the corresponding decrement is deferred to buffer release. Buffers
88 : * can undergo I/O multiple times in a hold-release cycle and per buffer I/O
89 : * tracking adds unnecessary overhead. This is used for sychronization purposes
90 : * with unmount (see xfs_buftarg_drain()), so all we really need is a count of
91 : * in-flight buffers.
92 : *
93 : * Buffers that are never released (e.g., superblock, iclog buffers) must set
94 : * the XBF_NO_IOACCT flag before I/O submission. Otherwise, the buftarg count
95 : * never reaches zero and unmount hangs indefinitely.
96 : */
97 : static inline void
98 67517842 : xfs_buf_ioacct_inc(
99 : struct xfs_buf *bp)
100 : {
101 67517842 : if (bp->b_flags & XBF_NO_IOACCT)
102 : return;
103 :
104 67382086 : ASSERT(bp->b_flags & XBF_ASYNC);
105 67382086 : spin_lock(&bp->b_lock);
106 67382156 : if (!(bp->b_state & XFS_BSTATE_IN_FLIGHT)) {
107 64783616 : bp->b_state |= XFS_BSTATE_IN_FLIGHT;
108 64783616 : percpu_counter_inc(&bp->b_target->bt_io_count);
109 : }
110 67382149 : spin_unlock(&bp->b_lock);
111 : }
112 :
113 : /*
114 : * Clear the in-flight state on a buffer about to be released to the LRU or
115 : * freed and unaccount from the buftarg.
116 : */
117 : static inline void
118 5430642246 : __xfs_buf_ioacct_dec(
119 : struct xfs_buf *bp)
120 : {
121 5430642246 : lockdep_assert_held(&bp->b_lock);
122 :
123 5430642246 : if (bp->b_state & XFS_BSTATE_IN_FLIGHT) {
124 64783428 : bp->b_state &= ~XFS_BSTATE_IN_FLIGHT;
125 64783428 : percpu_counter_dec(&bp->b_target->bt_io_count);
126 : }
127 5430642131 : }
128 :
129 : static inline void
130 137874 : xfs_buf_ioacct_dec(
131 : struct xfs_buf *bp)
132 : {
133 137874 : spin_lock(&bp->b_lock);
134 137874 : __xfs_buf_ioacct_dec(bp);
135 137874 : spin_unlock(&bp->b_lock);
136 137874 : }
137 :
138 : /*
139 : * When we mark a buffer stale, we remove the buffer from the LRU and clear the
140 : * b_lru_ref count so that the buffer is freed immediately when the buffer
141 : * reference count falls to zero. If the buffer is already on the LRU, we need
142 : * to remove the reference that LRU holds on the buffer.
143 : *
144 : * This prevents build-up of stale buffers on the LRU.
145 : */
146 : void
147 25037198 : xfs_buf_stale(
148 : struct xfs_buf *bp)
149 : {
150 25037198 : ASSERT(xfs_buf_islocked(bp));
151 :
152 25037198 : bp->b_flags |= XBF_STALE;
153 :
154 : /*
155 : * Clear the delwri status so that a delwri queue walker will not
156 : * flush this buffer to disk now that it is stale. The delwri queue has
157 : * a reference to the buffer, so this is safe to do.
158 : */
159 25037198 : bp->b_flags &= ~_XBF_DELWRI_Q;
160 :
161 : /*
162 : * Once the buffer is marked stale and unlocked, a subsequent lookup
163 : * could reset b_flags. There is no guarantee that the buffer is
164 : * unaccounted (released to LRU) before that occurs. Drop in-flight
165 : * status now to preserve accounting consistency.
166 : */
167 25037198 : spin_lock(&bp->b_lock);
168 25037521 : __xfs_buf_ioacct_dec(bp);
169 :
170 25037532 : atomic_set(&bp->b_lru_ref, 0);
171 50075746 : if (!(bp->b_state & XFS_BSTATE_DISPOSE) &&
172 25037077 : (list_lru_del(&bp->b_target->bt_lru, &bp->b_lru)))
173 4325556 : atomic_dec(&bp->b_hold);
174 :
175 25038670 : ASSERT(atomic_read(&bp->b_hold) >= 1);
176 25038670 : spin_unlock(&bp->b_lock);
177 25038047 : }
178 :
179 : static int
180 50137449 : xfs_buf_get_maps(
181 : struct xfs_buf *bp,
182 : int map_count)
183 : {
184 50137449 : ASSERT(bp->b_maps == NULL);
185 50137449 : bp->b_map_count = map_count;
186 :
187 50137449 : if (map_count == 1) {
188 50137409 : bp->b_maps = &bp->__b_map;
189 50137409 : return 0;
190 : }
191 :
192 40 : bp->b_maps = kmem_zalloc(map_count * sizeof(struct xfs_buf_map),
193 : KM_NOFS);
194 40 : if (!bp->b_maps)
195 0 : return -ENOMEM;
196 : return 0;
197 : }
198 :
199 : /*
200 : * Frees b_pages if it was allocated.
201 : */
202 : static void
203 : xfs_buf_free_maps(
204 : struct xfs_buf *bp)
205 : {
206 50093770 : if (bp->b_maps != &bp->__b_map) {
207 40 : kmem_free(bp->b_maps);
208 40 : bp->b_maps = NULL;
209 : }
210 : }
211 :
212 : static int
213 50138889 : _xfs_buf_alloc(
214 : struct xfs_buftarg *target,
215 : struct xfs_buf_map *map,
216 : int nmaps,
217 : xfs_buf_flags_t flags,
218 : struct xfs_buf **bpp)
219 : {
220 50138889 : struct xfs_buf *bp;
221 50138889 : int error;
222 50138889 : int i;
223 :
224 50138889 : *bpp = NULL;
225 50138889 : bp = kmem_cache_zalloc(xfs_buf_cache, GFP_NOFS | __GFP_NOFAIL);
226 :
227 : /*
228 : * We don't want certain flags to appear in b_flags unless they are
229 : * specifically set by later operations on the buffer.
230 : */
231 50136889 : flags &= ~(XBF_UNMAPPED | XBF_TRYLOCK | XBF_ASYNC | XBF_READ_AHEAD);
232 :
233 50136889 : atomic_set(&bp->b_hold, 1);
234 50136889 : atomic_set(&bp->b_lru_ref, 1);
235 50136889 : init_completion(&bp->b_iowait);
236 50133921 : INIT_LIST_HEAD(&bp->b_lru);
237 50133921 : INIT_LIST_HEAD(&bp->b_list);
238 50133921 : INIT_LIST_HEAD(&bp->b_li_list);
239 50133921 : sema_init(&bp->b_sema, 0); /* held, no waiters */
240 50133921 : spin_lock_init(&bp->b_lock);
241 50137323 : bp->b_target = target;
242 50137323 : bp->b_mount = target->bt_mount;
243 50137323 : bp->b_flags = flags;
244 :
245 : /*
246 : * Set length and io_length to the same value initially.
247 : * I/O routines should use io_length, which will be the same in
248 : * most cases but may be reset (e.g. XFS recovery).
249 : */
250 50137323 : error = xfs_buf_get_maps(bp, nmaps);
251 50137968 : if (error) {
252 0 : kmem_cache_free(xfs_buf_cache, bp);
253 0 : return error;
254 : }
255 :
256 50137968 : bp->b_rhash_key = map[0].bm_bn;
257 50137968 : bp->b_length = 0;
258 100279026 : for (i = 0; i < nmaps; i++) {
259 50141058 : bp->b_maps[i].bm_bn = map[i].bm_bn;
260 50141058 : bp->b_maps[i].bm_len = map[i].bm_len;
261 50141058 : bp->b_length += map[i].bm_len;
262 : }
263 :
264 50137968 : atomic_set(&bp->b_pin_count, 0);
265 50137968 : init_waitqueue_head(&bp->b_waiters);
266 :
267 50140177 : XFS_STATS_INC(bp->b_mount, xb_create);
268 50140445 : trace_xfs_buf_init(bp, _RET_IP_);
269 :
270 50139813 : *bpp = bp;
271 50139813 : return 0;
272 : }
273 :
274 : static void
275 138446 : xfs_buf_free_pages(
276 : struct xfs_buf *bp)
277 : {
278 138446 : uint i;
279 :
280 138446 : ASSERT(bp->b_flags & _XBF_PAGES);
281 :
282 138446 : if (xfs_buf_is_vmapped(bp))
283 62 : vm_unmap_ram(bp->b_addr, bp->b_page_count);
284 :
285 276954 : for (i = 0; i < bp->b_page_count; i++) {
286 138508 : if (bp->b_pages[i])
287 138508 : __free_page(bp->b_pages[i]);
288 : }
289 138446 : mm_account_reclaimed_pages(bp->b_page_count);
290 :
291 138446 : if (bp->b_pages != bp->b_page_array)
292 0 : kmem_free(bp->b_pages);
293 138446 : bp->b_pages = NULL;
294 138446 : bp->b_flags &= ~_XBF_PAGES;
295 138446 : }
296 :
297 : static void
298 50093770 : xfs_buf_free_callback(
299 : struct callback_head *cb)
300 : {
301 50093770 : struct xfs_buf *bp = container_of(cb, struct xfs_buf, b_rcu);
302 :
303 50093770 : xfs_buf_free_maps(bp);
304 50093770 : kmem_cache_free(xfs_buf_cache, bp);
305 50099633 : }
306 :
307 : static void
308 50142387 : xfs_buf_free(
309 : struct xfs_buf *bp)
310 : {
311 50142387 : trace_xfs_buf_free(bp, _RET_IP_);
312 :
313 50142394 : ASSERT(list_empty(&bp->b_lru));
314 :
315 50142394 : if (bp->b_flags & _XBF_PAGES)
316 138446 : xfs_buf_free_pages(bp);
317 50003948 : else if (bp->b_flags & _XBF_KMEM)
318 50003934 : kmem_free(bp->b_addr);
319 :
320 50142396 : call_rcu(&bp->b_rcu, xfs_buf_free_callback);
321 50142364 : }
322 :
323 : static int
324 50001505 : xfs_buf_alloc_kmem(
325 : struct xfs_buf *bp,
326 : xfs_buf_flags_t flags)
327 : {
328 50001505 : xfs_km_flags_t kmflag_mask = KM_NOFS;
329 50001505 : size_t size = BBTOB(bp->b_length);
330 :
331 : /* Assure zeroed buffer for non-read cases. */
332 50001505 : if (!(flags & XBF_READ))
333 24195065 : kmflag_mask |= KM_ZERO;
334 :
335 50001505 : bp->b_addr = kmem_alloc(size, kmflag_mask);
336 50000583 : if (!bp->b_addr)
337 : return -ENOMEM;
338 :
339 50000583 : if (((unsigned long)(bp->b_addr + size - 1) & PAGE_MASK) !=
340 : ((unsigned long)bp->b_addr & PAGE_MASK)) {
341 : /* b_addr spans two pages - use alloc_page instead */
342 0 : kmem_free(bp->b_addr);
343 0 : bp->b_addr = NULL;
344 0 : return -ENOMEM;
345 : }
346 50000583 : bp->b_offset = offset_in_page(bp->b_addr);
347 50000583 : bp->b_pages = bp->b_page_array;
348 50000583 : bp->b_pages[0] = kmem_to_page(bp->b_addr);
349 50001097 : bp->b_page_count = 1;
350 50001097 : bp->b_flags |= _XBF_KMEM;
351 50001097 : return 0;
352 : }
353 :
354 : static int
355 138443 : xfs_buf_alloc_pages(
356 : struct xfs_buf *bp,
357 : xfs_buf_flags_t flags)
358 : {
359 138443 : gfp_t gfp_mask = __GFP_NOWARN;
360 138443 : long filled = 0;
361 :
362 138443 : if (flags & XBF_READ_AHEAD)
363 : gfp_mask |= __GFP_NORETRY;
364 : else
365 138435 : gfp_mask |= GFP_NOFS;
366 :
367 : /* Make sure that we have a page list */
368 138443 : bp->b_page_count = DIV_ROUND_UP(BBTOB(bp->b_length), PAGE_SIZE);
369 138443 : if (bp->b_page_count <= XB_PAGES) {
370 138443 : bp->b_pages = bp->b_page_array;
371 : } else {
372 0 : bp->b_pages = kzalloc(sizeof(struct page *) * bp->b_page_count,
373 : gfp_mask);
374 0 : if (!bp->b_pages)
375 : return -ENOMEM;
376 : }
377 138443 : bp->b_flags |= _XBF_PAGES;
378 :
379 : /* Assure zeroed buffer for non-read cases. */
380 138443 : if (!(flags & XBF_READ))
381 138098 : gfp_mask |= __GFP_ZERO;
382 :
383 : /*
384 : * Bulk filling of pages can take multiple calls. Not filling the entire
385 : * array is not an allocation failure, so don't back off if we get at
386 : * least one extra page.
387 : */
388 138443 : for (;;) {
389 138443 : long last = filled;
390 :
391 138443 : filled = alloc_pages_bulk_array(gfp_mask, bp->b_page_count,
392 : bp->b_pages);
393 138443 : if (filled == bp->b_page_count) {
394 138443 : XFS_STATS_INC(bp->b_mount, xb_page_found);
395 138443 : break;
396 : }
397 :
398 0 : if (filled != last)
399 0 : continue;
400 :
401 0 : if (flags & XBF_READ_AHEAD) {
402 0 : xfs_buf_free_pages(bp);
403 0 : return -ENOMEM;
404 : }
405 :
406 0 : XFS_STATS_INC(bp->b_mount, xb_page_retries);
407 0 : memalloc_retry_wait(gfp_mask);
408 : }
409 138443 : return 0;
410 : }
411 :
412 : /*
413 : * Map buffer into kernel address-space if necessary.
414 : */
415 : STATIC int
416 138443 : _xfs_buf_map_pages(
417 : struct xfs_buf *bp,
418 : xfs_buf_flags_t flags)
419 : {
420 138443 : ASSERT(bp->b_flags & _XBF_PAGES);
421 138443 : if (bp->b_page_count == 1) {
422 : /* A single page buffer is always mappable */
423 138381 : bp->b_addr = page_address(bp->b_pages[0]);
424 62 : } else if (flags & XBF_UNMAPPED) {
425 0 : bp->b_addr = NULL;
426 : } else {
427 62 : int retried = 0;
428 62 : unsigned nofs_flag;
429 :
430 : /*
431 : * vm_map_ram() will allocate auxiliary structures (e.g.
432 : * pagetables) with GFP_KERNEL, yet we are likely to be under
433 : * GFP_NOFS context here. Hence we need to tell memory reclaim
434 : * that we are in such a context via PF_MEMALLOC_NOFS to prevent
435 : * memory reclaim re-entering the filesystem here and
436 : * potentially deadlocking.
437 : */
438 62 : nofs_flag = memalloc_nofs_save();
439 62 : do {
440 62 : bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count,
441 : -1);
442 62 : if (bp->b_addr)
443 : break;
444 0 : vm_unmap_aliases();
445 0 : } while (retried++ <= 1);
446 62 : memalloc_nofs_restore(nofs_flag);
447 :
448 62 : if (!bp->b_addr)
449 0 : return -ENOMEM;
450 : }
451 :
452 : return 0;
453 : }
454 :
455 : /*
456 : * Finding and Reading Buffers
457 : */
458 : static int
459 20743386446 : _xfs_buf_obj_cmp(
460 : struct rhashtable_compare_arg *arg,
461 : const void *obj)
462 : {
463 20743386446 : const struct xfs_buf_map *map = arg->key;
464 20743386446 : const struct xfs_buf *bp = obj;
465 :
466 : /*
467 : * The key hashing in the lookup path depends on the key being the
468 : * first element of the compare_arg, make sure to assert this.
469 : */
470 20743386446 : BUILD_BUG_ON(offsetof(struct xfs_buf_map, bm_bn) != 0);
471 :
472 20743386446 : if (bp->b_rhash_key != map->bm_bn)
473 : return 1;
474 :
475 15859671386 : if (unlikely(bp->b_length != map->bm_len)) {
476 : /*
477 : * found a block number match. If the range doesn't
478 : * match, the only way this is allowed is if the buffer
479 : * in the cache is stale and the transaction that made
480 : * it stale has not yet committed. i.e. we are
481 : * reallocating a busy extent. Skip this buffer and
482 : * continue searching for an exact match.
483 : */
484 4 : ASSERT(bp->b_flags & XBF_STALE);
485 4 : return 1;
486 : }
487 : return 0;
488 : }
489 :
490 : static const struct rhashtable_params xfs_buf_hash_params = {
491 : .min_size = 32, /* empty AGs have minimal footprint */
492 : .nelem_hint = 16,
493 : .key_len = sizeof(xfs_daddr_t),
494 : .key_offset = offsetof(struct xfs_buf, b_rhash_key),
495 : .head_offset = offsetof(struct xfs_buf, b_rhash_head),
496 : .automatic_shrinking = true,
497 : .obj_cmpfn = _xfs_buf_obj_cmp,
498 : };
499 :
500 : int
501 126902 : xfs_buf_hash_init(
502 : struct xfs_perag *pag)
503 : {
504 126902 : spin_lock_init(&pag->pag_buf_lock);
505 126902 : return rhashtable_init(&pag->pag_buf_hash, &xfs_buf_hash_params);
506 : }
507 :
508 : void
509 126914 : xfs_buf_hash_destroy(
510 : struct xfs_perag *pag)
511 : {
512 126914 : rhashtable_destroy(&pag->pag_buf_hash);
513 126914 : }
514 :
515 : static int
516 15907990164 : xfs_buf_map_verify(
517 : struct xfs_buftarg *btp,
518 : struct xfs_buf_map *map)
519 : {
520 15907990164 : xfs_daddr_t eofs;
521 :
522 : /* Check for IOs smaller than the sector size / not sector aligned */
523 15907990164 : ASSERT(!(BBTOB(map->bm_len) < btp->bt_meta_sectorsize));
524 15907990164 : ASSERT(!(BBTOB(map->bm_bn) & (xfs_off_t)btp->bt_meta_sectormask));
525 :
526 : /*
527 : * Corrupted block numbers can get through to here, unfortunately, so we
528 : * have to check that the buffer falls within the filesystem bounds.
529 : */
530 15907990164 : eofs = XFS_FSB_TO_BB(btp->bt_mount, btp->bt_mount->m_sb.sb_dblocks);
531 15907990164 : if (map->bm_bn < 0 || map->bm_bn >= eofs) {
532 0 : xfs_alert(btp->bt_mount,
533 : "%s: daddr 0x%llx out of range, EOFS 0x%llx",
534 : __func__, map->bm_bn, eofs);
535 0 : WARN_ON(1);
536 0 : return -EFSCORRUPTED;
537 : }
538 : return 0;
539 : }
540 :
541 : static int
542 15880108707 : xfs_buf_find_lock(
543 : struct xfs_buf *bp,
544 : xfs_buf_flags_t flags)
545 : {
546 15880108707 : if (flags & XBF_TRYLOCK) {
547 3618143817 : if (!xfs_buf_trylock(bp)) {
548 75959770 : XFS_STATS_INC(bp->b_mount, xb_busy_locked);
549 75959895 : return -EAGAIN;
550 : }
551 : } else {
552 12261964890 : xfs_buf_lock(bp);
553 12259913074 : XFS_STATS_INC(bp->b_mount, xb_get_locked_waited);
554 : }
555 :
556 : /*
557 : * if the buffer is stale, clear all the external state associated with
558 : * it. We need to keep flags such as how we allocated the buffer memory
559 : * intact here.
560 : */
561 15805315757 : if (bp->b_flags & XBF_STALE) {
562 30992 : ASSERT((bp->b_flags & _XBF_DELWRI_Q) == 0);
563 30992 : bp->b_flags &= _XBF_KMEM | _XBF_PAGES;
564 30992 : bp->b_ops = NULL;
565 : }
566 : return 0;
567 : }
568 :
569 : static inline int
570 15911680121 : xfs_buf_lookup(
571 : struct xfs_perag *pag,
572 : struct xfs_buf_map *map,
573 : xfs_buf_flags_t flags,
574 : struct xfs_buf **bpp)
575 : {
576 15911680121 : struct xfs_buf *bp;
577 15911680121 : int error;
578 :
579 15911680121 : rcu_read_lock();
580 15913828542 : bp = rhashtable_lookup(&pag->pag_buf_hash, map, xfs_buf_hash_params);
581 31784352029 : if (!bp || !atomic_inc_not_zero(&bp->b_hold)) {
582 50003937 : rcu_read_unlock();
583 50003937 : return -ENOENT;
584 : }
585 15876192630 : rcu_read_unlock();
586 :
587 15876733090 : error = xfs_buf_find_lock(bp, flags);
588 15873499846 : if (error) {
589 75959608 : xfs_buf_rele(bp);
590 75959608 : return error;
591 : }
592 :
593 15797540238 : trace_xfs_buf_find(bp, flags, _RET_IP_);
594 15800824013 : *bpp = bp;
595 15800824013 : return 0;
596 : }
597 :
598 : /*
599 : * Insert the new_bp into the hash table. This consumes the perag reference
600 : * taken for the lookup regardless of the result of the insert.
601 : */
602 : static int
603 50002493 : xfs_buf_find_insert(
604 : struct xfs_buftarg *btp,
605 : struct xfs_perag *pag,
606 : struct xfs_buf_map *cmap,
607 : struct xfs_buf_map *map,
608 : int nmaps,
609 : xfs_buf_flags_t flags,
610 : struct xfs_buf **bpp)
611 : {
612 50002493 : struct xfs_buf *new_bp;
613 50002493 : struct xfs_buf *bp;
614 50002493 : int error;
615 :
616 50002493 : error = _xfs_buf_alloc(btp, map, nmaps, flags, &new_bp);
617 50002049 : if (error)
618 0 : goto out_drop_pag;
619 :
620 : /*
621 : * For buffers that fit entirely within a single page, first attempt to
622 : * allocate the memory from the heap to minimise memory usage. If we
623 : * can't get heap memory for these small buffers, we fall back to using
624 : * the page allocator.
625 : */
626 100003084 : if (BBTOB(new_bp->b_length) >= PAGE_SIZE ||
627 50001572 : xfs_buf_alloc_kmem(new_bp, flags) < 0) {
628 747 : error = xfs_buf_alloc_pages(new_bp, flags);
629 572 : if (error)
630 0 : goto out_free_buf;
631 : }
632 :
633 50001607 : spin_lock(&pag->pag_buf_lock);
634 50003483 : bp = rhashtable_lookup_get_insert_fast(&pag->pag_buf_hash,
635 : &new_bp->b_rhash_head, xfs_buf_hash_params);
636 50003298 : if (IS_ERR(bp)) {
637 0 : error = PTR_ERR(bp);
638 0 : spin_unlock(&pag->pag_buf_lock);
639 0 : goto out_free_buf;
640 : }
641 50003298 : if (bp) {
642 : /* found an existing buffer */
643 1028 : atomic_inc(&bp->b_hold);
644 1028 : spin_unlock(&pag->pag_buf_lock);
645 1028 : error = xfs_buf_find_lock(bp, flags);
646 1028 : if (error)
647 2 : xfs_buf_rele(bp);
648 : else
649 1026 : *bpp = bp;
650 1028 : goto out_free_buf;
651 : }
652 :
653 : /* The new buffer keeps the perag reference until it is freed. */
654 50002270 : new_bp->b_pag = pag;
655 50002270 : spin_unlock(&pag->pag_buf_lock);
656 50001777 : *bpp = new_bp;
657 50001777 : return 0;
658 :
659 1028 : out_free_buf:
660 1028 : xfs_buf_free(new_bp);
661 1028 : out_drop_pag:
662 1028 : xfs_perag_put(pag);
663 1028 : return error;
664 : }
665 :
666 : /*
667 : * Assembles a buffer covering the specified range. The code is optimised for
668 : * cache hits, as metadata intensive workloads will see 3 orders of magnitude
669 : * more hits than misses.
670 : */
671 : int
672 15902511314 : xfs_buf_get_map(
673 : struct xfs_buftarg *btp,
674 : struct xfs_buf_map *map,
675 : int nmaps,
676 : xfs_buf_flags_t flags,
677 : struct xfs_buf **bpp)
678 : {
679 15902511314 : struct xfs_perag *pag;
680 15902511314 : struct xfs_buf *bp = NULL;
681 15902511314 : struct xfs_buf_map cmap = { .bm_bn = map[0].bm_bn };
682 15902511314 : int error;
683 15902511314 : int i;
684 :
685 31811774570 : for (i = 0; i < nmaps; i++)
686 15909263256 : cmap.bm_len += map[i].bm_len;
687 :
688 15902511314 : error = xfs_buf_map_verify(btp, &cmap);
689 15910379410 : if (error)
690 : return error;
691 :
692 15910958762 : pag = xfs_perag_get(btp->bt_mount,
693 : xfs_daddr_to_agno(btp->bt_mount, cmap.bm_bn));
694 :
695 15907315714 : error = xfs_buf_lookup(pag, &cmap, flags, &bp);
696 15926600425 : if (error && error != -ENOENT)
697 75959990 : goto out_put_perag;
698 :
699 : /* cache hits always outnumber misses by at least 10:1 */
700 15850640435 : if (unlikely(!bp)) {
701 50003243 : XFS_STATS_INC(btp->bt_mount, xb_miss_locked);
702 :
703 50002938 : if (flags & XBF_INCORE)
704 410 : goto out_put_perag;
705 :
706 : /* xfs_buf_find_insert() consumes the perag reference. */
707 50002528 : error = xfs_buf_find_insert(btp, pag, &cmap, map, nmaps,
708 : flags, &bp);
709 50002953 : if (error)
710 : return error;
711 : } else {
712 15800637192 : XFS_STATS_INC(btp->bt_mount, xb_get_locked);
713 15800998365 : xfs_perag_put(pag);
714 : }
715 :
716 : /* We do not hold a perag reference anymore. */
717 15846108439 : if (!bp->b_addr) {
718 572 : error = _xfs_buf_map_pages(bp, flags);
719 572 : if (unlikely(error)) {
720 0 : xfs_warn_ratelimited(btp->bt_mount,
721 : "%s: failed to map %u pages", __func__,
722 : bp->b_page_count);
723 0 : xfs_buf_relse(bp);
724 0 : return error;
725 : }
726 : }
727 :
728 : /*
729 : * Clear b_error if this is a lookup from a caller that doesn't expect
730 : * valid data to be found in the buffer.
731 : */
732 15846108439 : if (!(flags & XBF_READ))
733 42866844 : xfs_buf_ioerror(bp, 0);
734 :
735 15846108677 : XFS_STATS_INC(btp->bt_mount, xb_get);
736 15846576121 : trace_xfs_buf_get(bp, flags, _RET_IP_);
737 15851935640 : *bpp = bp;
738 15851935640 : return 0;
739 :
740 75960400 : out_put_perag:
741 75960400 : xfs_perag_put(pag);
742 75960400 : return error;
743 : }
744 :
745 : int
746 25832621 : _xfs_buf_read(
747 : struct xfs_buf *bp,
748 : xfs_buf_flags_t flags)
749 : {
750 25832621 : ASSERT(!(flags & XBF_WRITE));
751 25832621 : ASSERT(bp->b_maps[0].bm_bn != XFS_BUF_DADDR_NULL);
752 :
753 25832621 : bp->b_flags &= ~(XBF_WRITE | XBF_ASYNC | XBF_READ_AHEAD | XBF_DONE);
754 25832621 : bp->b_flags |= flags & (XBF_READ | XBF_ASYNC | XBF_READ_AHEAD);
755 :
756 25832621 : return xfs_buf_submit(bp);
757 : }
758 :
759 : /*
760 : * Reverify a buffer found in cache without an attached ->b_ops.
761 : *
762 : * If the caller passed an ops structure and the buffer doesn't have ops
763 : * assigned, set the ops and use it to verify the contents. If verification
764 : * fails, clear XBF_DONE. We assume the buffer has no recorded errors and is
765 : * already in XBF_DONE state on entry.
766 : *
767 : * Under normal operations, every in-core buffer is verified on read I/O
768 : * completion. There are two scenarios that can lead to in-core buffers without
769 : * an assigned ->b_ops. The first is during log recovery of buffers on a V4
770 : * filesystem, though these buffers are purged at the end of recovery. The
771 : * other is online repair, which intentionally reads with a NULL buffer ops to
772 : * run several verifiers across an in-core buffer in order to establish buffer
773 : * type. If repair can't establish that, the buffer will be left in memory
774 : * with NULL buffer ops.
775 : */
776 : int
777 16343951179 : xfs_buf_reverify(
778 : struct xfs_buf *bp,
779 : const struct xfs_buf_ops *ops)
780 : {
781 16343951179 : ASSERT(bp->b_flags & XBF_DONE);
782 16343951179 : ASSERT(bp->b_error == 0);
783 :
784 16343951179 : if (!ops || bp->b_ops)
785 : return 0;
786 :
787 79 : bp->b_ops = ops;
788 79 : bp->b_ops->verify_read(bp);
789 79 : if (bp->b_error)
790 77 : bp->b_flags &= ~XBF_DONE;
791 : return bp->b_error;
792 : }
793 :
794 : int
795 15858944147 : xfs_buf_read_map(
796 : struct xfs_buftarg *target,
797 : struct xfs_buf_map *map,
798 : int nmaps,
799 : xfs_buf_flags_t flags,
800 : struct xfs_buf **bpp,
801 : const struct xfs_buf_ops *ops,
802 : xfs_failaddr_t fa)
803 : {
804 15858944147 : struct xfs_buf *bp;
805 15858944147 : int error;
806 :
807 15858944147 : flags |= XBF_READ;
808 15858944147 : *bpp = NULL;
809 :
810 15858944147 : error = xfs_buf_get_map(target, map, nmaps, flags, &bp);
811 15882543960 : if (error)
812 : return error;
813 :
814 15806135838 : trace_xfs_buf_read(bp, flags, _RET_IP_);
815 :
816 15809184952 : if (!(bp->b_flags & XBF_DONE)) {
817 : /* Initiate the buffer read and wait. */
818 25822418 : XFS_STATS_INC(target->bt_mount, xb_get_read);
819 25822429 : bp->b_ops = ops;
820 25822429 : error = _xfs_buf_read(bp, flags);
821 :
822 : /* Readahead iodone already dropped the buffer, so exit. */
823 25417983 : if (flags & XBF_ASYNC)
824 : return 0;
825 : } else {
826 : /* Buffer already read; all we need to do is check it. */
827 15783362534 : error = xfs_buf_reverify(bp, ops);
828 :
829 : /* Readahead already finished; drop the buffer and exit. */
830 15785449566 : if (flags & XBF_ASYNC) {
831 3491096161 : xfs_buf_relse(bp);
832 3491073225 : return 0;
833 : }
834 :
835 : /* We do not want read in the flags */
836 12294353405 : bp->b_flags &= ~XBF_READ;
837 12294353405 : ASSERT(bp->b_ops != NULL || ops == NULL);
838 : }
839 :
840 : /*
841 : * If we've had a read error, then the contents of the buffer are
842 : * invalid and should not be used. To ensure that a followup read tries
843 : * to pull the buffer from disk again, we clear the XBF_DONE flag and
844 : * mark the buffer stale. This ensures that anyone who has a current
845 : * reference to the buffer will interpret it's contents correctly and
846 : * future cache lookups will also treat it as an empty, uninitialised
847 : * buffer.
848 : */
849 12303057941 : if (error) {
850 : /*
851 : * Check against log shutdown for error reporting because
852 : * metadata writeback may require a read first and we need to
853 : * report errors in metadata writeback until the log is shut
854 : * down. High level transaction read functions already check
855 : * against mount shutdown, anyway, so we only need to be
856 : * concerned about low level IO interactions here.
857 : */
858 76482 : if (!xlog_is_shutdown(target->bt_mount->m_log))
859 26396 : xfs_buf_ioerror_alert(bp, fa);
860 :
861 38288 : bp->b_flags &= ~XBF_DONE;
862 38288 : xfs_buf_stale(bp);
863 38281 : xfs_buf_relse(bp);
864 :
865 : /* bad CRC means corrupted metadata */
866 38280 : if (error == -EFSBADCRC)
867 668 : error = -EFSCORRUPTED;
868 38280 : return error;
869 : }
870 :
871 12303019700 : *bpp = bp;
872 12303019700 : return 0;
873 : }
874 :
875 : /*
876 : * If we are not low on memory then do the readahead in a deadlock
877 : * safe manner.
878 : */
879 : void
880 3579990791 : xfs_buf_readahead_map(
881 : struct xfs_buftarg *target,
882 : struct xfs_buf_map *map,
883 : int nmaps,
884 : const struct xfs_buf_ops *ops)
885 : {
886 3579990791 : struct xfs_buf *bp;
887 :
888 7160242127 : xfs_buf_read_map(target, map, nmaps,
889 : XBF_TRYLOCK | XBF_ASYNC | XBF_READ_AHEAD, &bp, ops,
890 3579990791 : __this_address);
891 3581485087 : }
892 :
893 : /*
894 : * Read an uncached buffer from disk. Allocates and returns a locked
895 : * buffer containing the disk contents or nothing. Uncached buffers always have
896 : * a cache index of XFS_BUF_DADDR_NULL so we can easily determine if the buffer
897 : * is cached or uncached during fault diagnosis.
898 : */
899 : int
900 67817 : xfs_buf_read_uncached(
901 : struct xfs_buftarg *target,
902 : xfs_daddr_t daddr,
903 : size_t numblks,
904 : xfs_buf_flags_t flags,
905 : struct xfs_buf **bpp,
906 : const struct xfs_buf_ops *ops)
907 : {
908 67817 : struct xfs_buf *bp;
909 67817 : int error;
910 :
911 67817 : *bpp = NULL;
912 :
913 67817 : error = xfs_buf_get_uncached(target, numblks, flags, &bp);
914 67817 : if (error)
915 : return error;
916 :
917 : /* set up the buffer for a read IO */
918 67817 : ASSERT(bp->b_map_count == 1);
919 67817 : bp->b_rhash_key = XFS_BUF_DADDR_NULL;
920 67817 : bp->b_maps[0].bm_bn = daddr;
921 67817 : bp->b_flags |= XBF_READ;
922 67817 : bp->b_ops = ops;
923 :
924 67817 : xfs_buf_submit(bp);
925 67817 : if (bp->b_error) {
926 16 : error = bp->b_error;
927 16 : xfs_buf_relse(bp);
928 16 : return error;
929 : }
930 :
931 67801 : *bpp = bp;
932 67801 : return 0;
933 : }
934 :
935 : int
936 137871 : xfs_buf_get_uncached(
937 : struct xfs_buftarg *target,
938 : size_t numblks,
939 : xfs_buf_flags_t flags,
940 : struct xfs_buf **bpp)
941 : {
942 137871 : int error;
943 137871 : struct xfs_buf *bp;
944 137871 : DEFINE_SINGLE_BUF_MAP(map, XFS_BUF_DADDR_NULL, numblks);
945 :
946 137871 : *bpp = NULL;
947 :
948 : /* flags might contain irrelevant bits, pass only what we care about */
949 137871 : error = _xfs_buf_alloc(target, &map, 1, flags & XBF_NO_IOACCT, &bp);
950 137871 : if (error)
951 : return error;
952 :
953 137871 : error = xfs_buf_alloc_pages(bp, flags);
954 137871 : if (error)
955 0 : goto fail_free_buf;
956 :
957 137871 : error = _xfs_buf_map_pages(bp, 0);
958 137871 : if (unlikely(error)) {
959 0 : xfs_warn(target->bt_mount,
960 : "%s: failed to map pages", __func__);
961 0 : goto fail_free_buf;
962 : }
963 :
964 137871 : trace_xfs_buf_get_uncached(bp, _RET_IP_);
965 137871 : *bpp = bp;
966 137871 : return 0;
967 :
968 0 : fail_free_buf:
969 0 : xfs_buf_free(bp);
970 0 : return error;
971 : }
972 :
973 : /*
974 : * Increment reference count on buffer, to hold the buffer concurrently
975 : * with another thread which may release (free) the buffer asynchronously.
976 : * Must hold the buffer already to call this function.
977 : */
978 : void
979 4287788910 : xfs_buf_hold(
980 : struct xfs_buf *bp)
981 : {
982 4287788910 : trace_xfs_buf_hold(bp, _RET_IP_);
983 4287953690 : atomic_inc(&bp->b_hold);
984 4287978429 : }
985 :
986 : /*
987 : * Release a hold on the specified buffer. If the hold count is 1, the buffer is
988 : * placed on LRU or freed (depending on b_lru_ref).
989 : */
990 : void
991 20281985977 : xfs_buf_rele(
992 : struct xfs_buf *bp)
993 : {
994 20281985977 : struct xfs_perag *pag = bp->b_pag;
995 20281985977 : bool release;
996 20281985977 : bool freebuf = false;
997 :
998 20281985977 : trace_xfs_buf_rele(bp, _RET_IP_);
999 :
1000 20285365676 : if (!pag) {
1001 9860204 : ASSERT(list_empty(&bp->b_lru));
1002 19720432 : if (atomic_dec_and_test(&bp->b_hold)) {
1003 137874 : xfs_buf_ioacct_dec(bp);
1004 137874 : xfs_buf_free(bp);
1005 : }
1006 9860228 : return;
1007 : }
1008 :
1009 20275505472 : ASSERT(atomic_read(&bp->b_hold) > 0);
1010 :
1011 : /*
1012 : * We grab the b_lock here first to serialise racing xfs_buf_rele()
1013 : * calls. The pag_buf_lock being taken on the last reference only
1014 : * serialises against racing lookups in xfs_buf_find(). IOWs, the second
1015 : * to last reference we drop here is not serialised against the last
1016 : * reference until we take bp->b_lock. Hence if we don't grab b_lock
1017 : * first, the last "release" reference can win the race to the lock and
1018 : * free the buffer before the second-to-last reference is processed,
1019 : * leading to a use-after-free scenario.
1020 : */
1021 20275505472 : spin_lock(&bp->b_lock);
1022 20291711812 : release = atomic_dec_and_lock(&bp->b_hold, &pag->pag_buf_lock);
1023 20299740431 : if (!release) {
1024 : /*
1025 : * Drop the in-flight state if the buffer is already on the LRU
1026 : * and it holds the only reference. This is racy because we
1027 : * haven't acquired the pag lock, but the use of _XBF_IN_FLIGHT
1028 : * ensures the decrement occurs only once per-buf.
1029 : */
1030 20218362925 : if ((atomic_read(&bp->b_hold) == 1) && !list_empty(&bp->b_lru))
1031 5323041425 : __xfs_buf_ioacct_dec(bp);
1032 20218532202 : goto out_unlock;
1033 : }
1034 :
1035 : /* the last reference has been dropped ... */
1036 81377506 : __xfs_buf_ioacct_dec(bp);
1037 81377512 : if (!(bp->b_flags & XBF_STALE) && atomic_read(&bp->b_lru_ref)) {
1038 : /*
1039 : * If the buffer is added to the LRU take a new reference to the
1040 : * buffer for the LRU and clear the (now stale) dispose list
1041 : * state flag
1042 : */
1043 31374036 : if (list_lru_add(&bp->b_target->bt_lru, &bp->b_lru)) {
1044 31374220 : bp->b_state &= ~XFS_BSTATE_DISPOSE;
1045 31374220 : atomic_inc(&bp->b_hold);
1046 : }
1047 31374220 : spin_unlock(&pag->pag_buf_lock);
1048 : } else {
1049 : /*
1050 : * most of the time buffers will already be removed from the
1051 : * LRU, so optimise that case by checking for the
1052 : * XFS_BSTATE_DISPOSE flag indicating the last list the buffer
1053 : * was on was the disposal list
1054 : */
1055 50003476 : if (!(bp->b_state & XFS_BSTATE_DISPOSE)) {
1056 23255415 : list_lru_del(&bp->b_target->bt_lru, &bp->b_lru);
1057 : } else {
1058 26748061 : ASSERT(list_empty(&bp->b_lru));
1059 : }
1060 :
1061 50003504 : ASSERT(!(bp->b_flags & _XBF_DELWRI_Q));
1062 50003504 : rhashtable_remove_fast(&pag->pag_buf_hash, &bp->b_rhash_head,
1063 : xfs_buf_hash_params);
1064 50003447 : spin_unlock(&pag->pag_buf_lock);
1065 50003489 : xfs_perag_put(pag);
1066 50003489 : freebuf = true;
1067 : }
1068 :
1069 20299909891 : out_unlock:
1070 20299909891 : spin_unlock(&bp->b_lock);
1071 :
1072 20298543846 : if (freebuf)
1073 50003491 : xfs_buf_free(bp);
1074 : }
1075 :
1076 :
1077 : /*
1078 : * Lock a buffer object, if it is not already locked.
1079 : *
1080 : * If we come across a stale, pinned, locked buffer, we know that we are
1081 : * being asked to lock a buffer that has been reallocated. Because it is
1082 : * pinned, we know that the log has not been pushed to disk and hence it
1083 : * will still be locked. Rather than continuing to have trylock attempts
1084 : * fail until someone else pushes the log, push it ourselves before
1085 : * returning. This means that the xfsaild will not get stuck trying
1086 : * to push on stale inode buffers.
1087 : */
1088 : int
1089 3720321438 : xfs_buf_trylock(
1090 : struct xfs_buf *bp)
1091 : {
1092 3720321438 : int locked;
1093 :
1094 3720321438 : locked = down_trylock(&bp->b_sema) == 0;
1095 3720381329 : if (locked)
1096 3644050350 : trace_xfs_buf_trylock(bp, _RET_IP_);
1097 : else
1098 76330979 : trace_xfs_buf_trylock_fail(bp, _RET_IP_);
1099 3720695715 : return locked;
1100 : }
1101 :
1102 : /*
1103 : * Lock a buffer object.
1104 : *
1105 : * If we come across a stale, pinned, locked buffer, we know that we
1106 : * are being asked to lock a buffer that has been reallocated. Because
1107 : * it is pinned, we know that the log has not been pushed to disk and
1108 : * hence it will still be locked. Rather than sleeping until someone
1109 : * else pushes the log, push it ourselves before trying to get the lock.
1110 : */
1111 : void
1112 12289594483 : xfs_buf_lock(
1113 : struct xfs_buf *bp)
1114 : {
1115 12289594483 : trace_xfs_buf_lock(bp, _RET_IP_);
1116 :
1117 12286297987 : if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE))
1118 22067 : xfs_log_force(bp->b_mount, 0);
1119 12286297987 : down(&bp->b_sema);
1120 :
1121 12286184056 : trace_xfs_buf_lock_done(bp, _RET_IP_);
1122 12290114647 : }
1123 :
1124 : void
1125 15962777708 : xfs_buf_unlock(
1126 : struct xfs_buf *bp)
1127 : {
1128 15962777708 : ASSERT(xfs_buf_islocked(bp));
1129 :
1130 15962777708 : up(&bp->b_sema);
1131 15970193678 : trace_xfs_buf_unlock(bp, _RET_IP_);
1132 15974124912 : }
1133 :
1134 : STATIC void
1135 69258299 : xfs_buf_wait_unpin(
1136 : struct xfs_buf *bp)
1137 : {
1138 69258299 : DECLARE_WAITQUEUE (wait, current);
1139 :
1140 69258299 : if (atomic_read(&bp->b_pin_count) == 0)
1141 69255457 : return;
1142 :
1143 2842 : add_wait_queue(&bp->b_waiters, &wait);
1144 8526 : for (;;) {
1145 5684 : set_current_state(TASK_UNINTERRUPTIBLE);
1146 5684 : if (atomic_read(&bp->b_pin_count) == 0)
1147 : break;
1148 2842 : io_schedule();
1149 : }
1150 2842 : remove_wait_queue(&bp->b_waiters, &wait);
1151 2842 : set_current_state(TASK_RUNNING);
1152 : }
1153 :
1154 : static void
1155 4199 : xfs_buf_ioerror_alert_ratelimited(
1156 : struct xfs_buf *bp)
1157 : {
1158 4199 : static unsigned long lasttime;
1159 4199 : static struct xfs_buftarg *lasttarg;
1160 :
1161 4199 : if (bp->b_target != lasttarg ||
1162 4178 : time_after(jiffies, (lasttime + 5*HZ))) {
1163 23 : lasttime = jiffies;
1164 23 : xfs_buf_ioerror_alert(bp, __this_address);
1165 : }
1166 4199 : lasttarg = bp->b_target;
1167 4199 : }
1168 :
1169 : /*
1170 : * Account for this latest trip around the retry handler, and decide if
1171 : * we've failed enough times to constitute a permanent failure.
1172 : */
1173 : static bool
1174 3977 : xfs_buf_ioerror_permanent(
1175 : struct xfs_buf *bp,
1176 : struct xfs_error_cfg *cfg)
1177 : {
1178 3977 : struct xfs_mount *mp = bp->b_mount;
1179 :
1180 3977 : if (cfg->max_retries != XFS_ERR_RETRY_FOREVER &&
1181 16 : ++bp->b_retries > cfg->max_retries)
1182 : return true;
1183 3961 : if (cfg->retry_timeout != XFS_ERR_RETRY_FOREVER &&
1184 0 : time_after(jiffies, cfg->retry_timeout + bp->b_first_retry_time))
1185 : return true;
1186 :
1187 : /* At unmount we may treat errors differently */
1188 7922 : if (xfs_is_unmounting(mp) && mp->m_fail_unmount)
1189 3 : return true;
1190 :
1191 : return false;
1192 : }
1193 :
1194 : /*
1195 : * On a sync write or shutdown we just want to stale the buffer and let the
1196 : * caller handle the error in bp->b_error appropriately.
1197 : *
1198 : * If the write was asynchronous then no one will be looking for the error. If
1199 : * this is the first failure of this type, clear the error state and write the
1200 : * buffer out again. This means we always retry an async write failure at least
1201 : * once, but we also need to set the buffer up to behave correctly now for
1202 : * repeated failures.
1203 : *
1204 : * If we get repeated async write failures, then we take action according to the
1205 : * error configuration we have been set up to use.
1206 : *
1207 : * Returns true if this function took care of error handling and the caller must
1208 : * not touch the buffer again. Return false if the caller should proceed with
1209 : * normal I/O completion handling.
1210 : */
1211 : static bool
1212 2186392 : xfs_buf_ioend_handle_error(
1213 : struct xfs_buf *bp)
1214 : {
1215 2186392 : struct xfs_mount *mp = bp->b_mount;
1216 2186392 : struct xfs_error_cfg *cfg;
1217 :
1218 : /*
1219 : * If we've already shutdown the journal because of I/O errors, there's
1220 : * no point in giving this a retry.
1221 : */
1222 4372784 : if (xlog_is_shutdown(mp->m_log))
1223 2182193 : goto out_stale;
1224 :
1225 4199 : xfs_buf_ioerror_alert_ratelimited(bp);
1226 :
1227 : /*
1228 : * We're not going to bother about retrying this during recovery.
1229 : * One strike!
1230 : */
1231 4199 : if (bp->b_flags & _XBF_LOGRECOVERY) {
1232 0 : xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR);
1233 0 : return false;
1234 : }
1235 :
1236 : /*
1237 : * Synchronous writes will have callers process the error.
1238 : */
1239 4199 : if (!(bp->b_flags & XBF_ASYNC))
1240 0 : goto out_stale;
1241 :
1242 4199 : trace_xfs_buf_iodone_async(bp, _RET_IP_);
1243 :
1244 4199 : cfg = xfs_error_get_cfg(mp, XFS_ERR_METADATA, bp->b_error);
1245 4199 : if (bp->b_last_error != bp->b_error ||
1246 3977 : !(bp->b_flags & (XBF_STALE | XBF_WRITE_FAIL))) {
1247 222 : bp->b_last_error = bp->b_error;
1248 222 : if (cfg->retry_timeout != XFS_ERR_RETRY_FOREVER &&
1249 158 : !bp->b_first_retry_time)
1250 158 : bp->b_first_retry_time = jiffies;
1251 222 : goto resubmit;
1252 : }
1253 :
1254 : /*
1255 : * Permanent error - we need to trigger a shutdown if we haven't already
1256 : * to indicate that inconsistency will result from this action.
1257 : */
1258 3977 : if (xfs_buf_ioerror_permanent(bp, cfg)) {
1259 19 : xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR);
1260 19 : goto out_stale;
1261 : }
1262 :
1263 : /* Still considered a transient error. Caller will schedule retries. */
1264 3958 : if (bp->b_flags & _XBF_INODES)
1265 0 : xfs_buf_inode_io_fail(bp);
1266 3958 : else if (bp->b_flags & _XBF_DQUOTS)
1267 42 : xfs_buf_dquot_io_fail(bp);
1268 : else
1269 3916 : ASSERT(list_empty(&bp->b_li_list));
1270 3958 : xfs_buf_ioerror(bp, 0);
1271 3958 : xfs_buf_relse(bp);
1272 3958 : return true;
1273 :
1274 : resubmit:
1275 222 : xfs_buf_ioerror(bp, 0);
1276 222 : bp->b_flags |= (XBF_DONE | XBF_WRITE_FAIL);
1277 222 : xfs_buf_submit(bp);
1278 222 : return true;
1279 2182212 : out_stale:
1280 2182212 : xfs_buf_stale(bp);
1281 2182212 : bp->b_flags |= XBF_DONE;
1282 2182212 : bp->b_flags &= ~XBF_WRITE;
1283 2182212 : trace_xfs_buf_error_relse(bp, _RET_IP_);
1284 2182212 : return false;
1285 : }
1286 :
1287 : static void
1288 97340985 : xfs_buf_ioend(
1289 : struct xfs_buf *bp)
1290 : {
1291 97340985 : trace_xfs_buf_iodone(bp, _RET_IP_);
1292 :
1293 : /*
1294 : * Pull in IO completion errors now. We are guaranteed to be running
1295 : * single threaded, so we don't need the lock to read b_io_error.
1296 : */
1297 97340989 : if (!bp->b_error && bp->b_io_error)
1298 57798 : xfs_buf_ioerror(bp, bp->b_io_error);
1299 :
1300 97340986 : if (bp->b_flags & XBF_READ) {
1301 25900672 : if (!bp->b_error && bp->b_ops)
1302 23755704 : bp->b_ops->verify_read(bp);
1303 25900673 : if (!bp->b_error)
1304 25833102 : bp->b_flags |= XBF_DONE;
1305 : } else {
1306 71440314 : if (!bp->b_error) {
1307 69253921 : bp->b_flags &= ~XBF_WRITE_FAIL;
1308 69253921 : bp->b_flags |= XBF_DONE;
1309 : }
1310 :
1311 71440314 : if (unlikely(bp->b_error) && xfs_buf_ioend_handle_error(bp))
1312 : return;
1313 :
1314 : /* clear the retry state */
1315 71436133 : bp->b_last_error = 0;
1316 71436133 : bp->b_retries = 0;
1317 71436133 : bp->b_first_retry_time = 0;
1318 :
1319 : /*
1320 : * Note that for things like remote attribute buffers, there may
1321 : * not be a buffer log item here, so processing the buffer log
1322 : * item must remain optional.
1323 : */
1324 71436133 : if (bp->b_log_item)
1325 38804293 : xfs_buf_item_done(bp);
1326 :
1327 71436132 : if (bp->b_flags & _XBF_INODES)
1328 20473874 : xfs_buf_inode_iodone(bp);
1329 50962258 : else if (bp->b_flags & _XBF_DQUOTS)
1330 6914937 : xfs_buf_dquot_iodone(bp);
1331 :
1332 : }
1333 :
1334 97336805 : bp->b_flags &= ~(XBF_READ | XBF_WRITE | XBF_READ_AHEAD |
1335 : _XBF_LOGRECOVERY);
1336 :
1337 97336805 : if (bp->b_flags & XBF_ASYNC)
1338 69695946 : xfs_buf_relse(bp);
1339 : else
1340 27640859 : complete(&bp->b_iowait);
1341 : }
1342 :
1343 : static void
1344 95099615 : xfs_buf_ioend_work(
1345 : struct work_struct *work)
1346 : {
1347 95099615 : struct xfs_buf *bp =
1348 95099615 : container_of(work, struct xfs_buf, b_ioend_work);
1349 :
1350 95099615 : xfs_buf_ioend(bp);
1351 95099614 : }
1352 :
1353 : static void
1354 95099615 : xfs_buf_ioend_async(
1355 : struct xfs_buf *bp)
1356 : {
1357 95099615 : INIT_WORK(&bp->b_ioend_work, xfs_buf_ioend_work);
1358 95099615 : queue_work(bp->b_mount->m_buf_workqueue, &bp->b_ioend_work);
1359 95099615 : }
1360 :
1361 : void
1362 45125403 : __xfs_buf_ioerror(
1363 : struct xfs_buf *bp,
1364 : int error,
1365 : xfs_failaddr_t failaddr)
1366 : {
1367 45125403 : ASSERT(error <= 0 && error >= -1000);
1368 45125403 : bp->b_error = error;
1369 45125403 : trace_xfs_buf_ioerror(bp, error, failaddr);
1370 45126356 : }
1371 :
1372 : void
1373 26431 : xfs_buf_ioerror_alert(
1374 : struct xfs_buf *bp,
1375 : xfs_failaddr_t func)
1376 : {
1377 26431 : xfs_buf_alert_ratelimited(bp, "XFS: metadata IO error",
1378 : "metadata I/O error in \"%pS\" at daddr 0x%llx len %d error %d",
1379 : func, (uint64_t)xfs_buf_daddr(bp),
1380 26431 : bp->b_length, -bp->b_error);
1381 26466 : }
1382 :
1383 : /*
1384 : * To simulate an I/O failure, the buffer must be locked and held with at least
1385 : * three references. The LRU reference is dropped by the stale call. The buf
1386 : * item reference is dropped via ioend processing. The third reference is owned
1387 : * by the caller and is dropped on I/O completion if the buffer is XBF_ASYNC.
1388 : */
1389 : void
1390 2192801 : xfs_buf_ioend_fail(
1391 : struct xfs_buf *bp)
1392 : {
1393 2192801 : bp->b_flags &= ~XBF_DONE;
1394 2192801 : xfs_buf_stale(bp);
1395 2192800 : xfs_buf_ioerror(bp, -EIO);
1396 2192800 : xfs_buf_ioend(bp);
1397 2192801 : }
1398 :
1399 : int
1400 562 : xfs_bwrite(
1401 : struct xfs_buf *bp)
1402 : {
1403 562 : int error;
1404 :
1405 562 : ASSERT(xfs_buf_islocked(bp));
1406 :
1407 562 : bp->b_flags |= XBF_WRITE;
1408 562 : bp->b_flags &= ~(XBF_ASYNC | XBF_READ | _XBF_DELWRI_Q |
1409 : XBF_DONE);
1410 :
1411 562 : error = xfs_buf_submit(bp);
1412 562 : if (error)
1413 0 : xfs_force_shutdown(bp->b_mount, SHUTDOWN_META_IO_ERROR);
1414 562 : return error;
1415 : }
1416 :
1417 : static void
1418 95148260 : xfs_buf_bio_end_io(
1419 : struct bio *bio)
1420 : {
1421 95148260 : struct xfs_buf *bp = (struct xfs_buf *)bio->bi_private;
1422 :
1423 95148260 : if (!bio->bi_status &&
1424 146051795 : (bp->b_flags & XBF_WRITE) && (bp->b_flags & XBF_ASYNC) &&
1425 50961333 : XFS_TEST_ERROR(false, bp->b_mount, XFS_ERRTAG_BUF_IOERROR))
1426 0 : bio->bi_status = BLK_STS_IOERR;
1427 :
1428 : /*
1429 : * don't overwrite existing errors - otherwise we can lose errors on
1430 : * buffers that require multiple bios to complete.
1431 : */
1432 95148260 : if (bio->bi_status) {
1433 57798 : int error = blk_status_to_errno(bio->bi_status);
1434 :
1435 57796 : cmpxchg(&bp->b_io_error, 0, error);
1436 : }
1437 :
1438 95148258 : if (!bp->b_error && xfs_buf_is_vmapped(bp) && (bp->b_flags & XBF_READ))
1439 : invalidate_kernel_vmap_range(bp->b_addr, xfs_buf_vmap_len(bp));
1440 :
1441 190296517 : if (atomic_dec_and_test(&bp->b_io_remaining) == 1)
1442 95073275 : xfs_buf_ioend_async(bp);
1443 95148259 : bio_put(bio);
1444 95148259 : }
1445 :
1446 : static void
1447 95147891 : xfs_buf_ioapply_map(
1448 : struct xfs_buf *bp,
1449 : int map,
1450 : int *buf_offset,
1451 : int *count,
1452 : blk_opf_t op)
1453 : {
1454 95147891 : int page_index;
1455 95147891 : unsigned int total_nr_pages = bp->b_page_count;
1456 95147891 : int nr_pages;
1457 95147891 : struct bio *bio;
1458 95147891 : sector_t sector = bp->b_maps[map].bm_bn;
1459 95147891 : int size;
1460 95147891 : int offset;
1461 :
1462 : /* skip the pages in the buffer before the start offset */
1463 95147891 : page_index = 0;
1464 95147891 : offset = *buf_offset;
1465 95147891 : while (offset >= PAGE_SIZE) {
1466 0 : page_index++;
1467 0 : offset -= PAGE_SIZE;
1468 : }
1469 :
1470 : /*
1471 : * Limit the IO size to the length of the current vector, and update the
1472 : * remaining IO count for the next time around.
1473 : */
1474 95147891 : size = min_t(int, BBTOB(bp->b_maps[map].bm_len), *count);
1475 95147891 : *count -= size;
1476 95147891 : *buf_offset += size;
1477 :
1478 95147891 : next_chunk:
1479 95147891 : atomic_inc(&bp->b_io_remaining);
1480 95147974 : nr_pages = bio_max_segs(total_nr_pages);
1481 :
1482 95147974 : bio = bio_alloc(bp->b_target->bt_bdev, nr_pages, op, GFP_NOIO);
1483 95147773 : bio->bi_iter.bi_sector = sector;
1484 95147773 : bio->bi_end_io = xfs_buf_bio_end_io;
1485 95147773 : bio->bi_private = bp;
1486 :
1487 190295416 : for (; size && nr_pages; nr_pages--, page_index++) {
1488 95147807 : int rbytes, nbytes = PAGE_SIZE - offset;
1489 :
1490 95147807 : if (nbytes > size)
1491 : nbytes = size;
1492 :
1493 95147807 : rbytes = bio_add_page(bio, bp->b_pages[page_index], nbytes,
1494 : offset);
1495 95147643 : if (rbytes < nbytes)
1496 : break;
1497 :
1498 95147643 : offset = 0;
1499 95147643 : sector += BTOBB(nbytes);
1500 95147643 : size -= nbytes;
1501 95147643 : total_nr_pages--;
1502 : }
1503 :
1504 95147609 : if (likely(bio->bi_iter.bi_size)) {
1505 95147609 : if (xfs_buf_is_vmapped(bp)) {
1506 : flush_kernel_vmap_range(bp->b_addr,
1507 : xfs_buf_vmap_len(bp));
1508 : }
1509 95147609 : submit_bio(bio);
1510 95147576 : if (size)
1511 0 : goto next_chunk;
1512 : } else {
1513 : /*
1514 : * This is guaranteed not to be the last io reference count
1515 : * because the caller (xfs_buf_submit) holds a count itself.
1516 : */
1517 0 : atomic_dec(&bp->b_io_remaining);
1518 0 : xfs_buf_ioerror(bp, -EIO);
1519 0 : bio_put(bio);
1520 : }
1521 :
1522 95147576 : }
1523 :
1524 : STATIC void
1525 95147884 : _xfs_buf_ioapply(
1526 : struct xfs_buf *bp)
1527 : {
1528 95147884 : struct blk_plug plug;
1529 95147884 : blk_opf_t op;
1530 95147884 : int offset;
1531 95147884 : int size;
1532 95147884 : int i;
1533 :
1534 : /*
1535 : * Make sure we capture only current IO errors rather than stale errors
1536 : * left over from previous use of the buffer (e.g. failed readahead).
1537 : */
1538 95147884 : bp->b_error = 0;
1539 :
1540 95147884 : if (bp->b_flags & XBF_WRITE) {
1541 69258300 : op = REQ_OP_WRITE;
1542 :
1543 : /*
1544 : * Run the write verifier callback function if it exists. If
1545 : * this function fails it will mark the buffer with an error and
1546 : * the IO should not be dispatched.
1547 : */
1548 69258300 : if (bp->b_ops) {
1549 69258300 : bp->b_ops->verify_write(bp);
1550 69258299 : if (bp->b_error) {
1551 4 : xfs_force_shutdown(bp->b_mount,
1552 : SHUTDOWN_CORRUPT_INCORE);
1553 4 : return;
1554 : }
1555 0 : } else if (bp->b_rhash_key != XFS_BUF_DADDR_NULL) {
1556 0 : struct xfs_mount *mp = bp->b_mount;
1557 :
1558 : /*
1559 : * non-crc filesystems don't attach verifiers during
1560 : * log recovery, so don't warn for such filesystems.
1561 : */
1562 0 : if (xfs_has_crc(mp)) {
1563 0 : xfs_warn(mp,
1564 : "%s: no buf ops on daddr 0x%llx len %d",
1565 : __func__, xfs_buf_daddr(bp),
1566 : bp->b_length);
1567 0 : xfs_hex_dump(bp->b_addr,
1568 : XFS_CORRUPTION_DUMP_LEN);
1569 0 : dump_stack();
1570 : }
1571 : }
1572 : } else {
1573 25889584 : op = REQ_OP_READ;
1574 25889584 : if (bp->b_flags & XBF_READ_AHEAD)
1575 16552264 : op |= REQ_RAHEAD;
1576 : }
1577 :
1578 : /* we only use the buffer cache for meta-data */
1579 95147879 : op |= REQ_META;
1580 :
1581 : /*
1582 : * Walk all the vectors issuing IO on them. Set up the initial offset
1583 : * into the buffer and the desired IO size before we start -
1584 : * _xfs_buf_ioapply_vec() will modify them appropriately for each
1585 : * subsequent call.
1586 : */
1587 95147879 : offset = bp->b_offset;
1588 95147879 : size = BBTOB(bp->b_length);
1589 95147879 : blk_start_plug(&plug);
1590 190295798 : for (i = 0; i < bp->b_map_count; i++) {
1591 95147919 : xfs_buf_ioapply_map(bp, i, &offset, &size, op);
1592 95147597 : if (bp->b_error)
1593 : break;
1594 95147597 : if (size <= 0)
1595 : break; /* all done */
1596 : }
1597 95147521 : blk_finish_plug(&plug);
1598 : }
1599 :
1600 : /*
1601 : * Wait for I/O completion of a sync buffer and return the I/O error code.
1602 : */
1603 : static int
1604 27630119 : xfs_buf_iowait(
1605 : struct xfs_buf *bp)
1606 : {
1607 27630119 : ASSERT(!(bp->b_flags & XBF_ASYNC));
1608 :
1609 27630119 : trace_xfs_buf_iowait(bp, _RET_IP_);
1610 27630145 : wait_for_completion(&bp->b_iowait);
1611 27629972 : trace_xfs_buf_iowait_done(bp, _RET_IP_);
1612 :
1613 27629932 : return bp->b_error;
1614 : }
1615 :
1616 : /*
1617 : * Buffer I/O submission path, read or write. Asynchronous submission transfers
1618 : * the buffer lock ownership and the current reference to the IO. It is not
1619 : * safe to reference the buffer after a call to this function unless the caller
1620 : * holds an additional reference itself.
1621 : */
1622 : static int
1623 96465191 : __xfs_buf_submit(
1624 : struct xfs_buf *bp,
1625 : bool wait)
1626 : {
1627 96465191 : int error = 0;
1628 :
1629 96465191 : trace_xfs_buf_submit(bp, _RET_IP_);
1630 :
1631 96465195 : ASSERT(!(bp->b_flags & _XBF_DELWRI_Q));
1632 :
1633 : /*
1634 : * On log shutdown we stale and complete the buffer immediately. We can
1635 : * be called to read the superblock before the log has been set up, so
1636 : * be careful checking the log state.
1637 : *
1638 : * Checking the mount shutdown state here can result in the log tail
1639 : * moving inappropriately on disk as the log may not yet be shut down.
1640 : * i.e. failing this buffer on mount shutdown can remove it from the AIL
1641 : * and move the tail of the log forwards without having written this
1642 : * buffer to disk. This corrupts the log tail state in memory, and
1643 : * because the log may not be shut down yet, it can then be propagated
1644 : * to disk before the log is shutdown. Hence we check log shutdown
1645 : * state here rather than mount state to avoid corrupting the log tail
1646 : * on shutdown.
1647 : */
1648 192862667 : if (bp->b_mount->m_log &&
1649 : xlog_is_shutdown(bp->b_mount->m_log)) {
1650 1317473 : xfs_buf_ioend_fail(bp);
1651 1317473 : return -EIO;
1652 : }
1653 :
1654 : /*
1655 : * Grab a reference so the buffer does not go away underneath us. For
1656 : * async buffers, I/O completion drops the callers reference, which
1657 : * could occur before submission returns.
1658 : */
1659 95147722 : xfs_buf_hold(bp);
1660 :
1661 95147763 : if (bp->b_flags & XBF_WRITE)
1662 69258296 : xfs_buf_wait_unpin(bp);
1663 :
1664 : /* clear the internal error state to avoid spurious errors */
1665 95147768 : bp->b_io_error = 0;
1666 :
1667 : /*
1668 : * Set the count to 1 initially, this will stop an I/O completion
1669 : * callout which happens before we have started all the I/O from calling
1670 : * xfs_buf_ioend too early.
1671 : */
1672 95147768 : atomic_set(&bp->b_io_remaining, 1);
1673 95147768 : if (bp->b_flags & XBF_ASYNC)
1674 67517872 : xfs_buf_ioacct_inc(bp);
1675 95147769 : _xfs_buf_ioapply(bp);
1676 :
1677 : /*
1678 : * If _xfs_buf_ioapply failed, we can get back here with only the IO
1679 : * reference we took above. If we drop it to zero, run completion so
1680 : * that we don't return to the caller with completion still pending.
1681 : */
1682 190295723 : if (atomic_dec_and_test(&bp->b_io_remaining) == 1) {
1683 74911 : if (bp->b_error || !(bp->b_flags & XBF_ASYNC))
1684 48571 : xfs_buf_ioend(bp);
1685 : else
1686 26340 : xfs_buf_ioend_async(bp);
1687 : }
1688 :
1689 95147912 : if (wait)
1690 9337979 : error = xfs_buf_iowait(bp);
1691 :
1692 : /*
1693 : * Release the hold that keeps the buffer referenced for the entire
1694 : * I/O. Note that if the buffer is async, it is not safe to reference
1695 : * after this release.
1696 : */
1697 95147655 : xfs_buf_rele(bp);
1698 95147655 : return error;
1699 : }
1700 :
1701 : void *
1702 12501905636 : xfs_buf_offset(
1703 : struct xfs_buf *bp,
1704 : size_t offset)
1705 : {
1706 12501905636 : struct page *page;
1707 :
1708 12501905636 : if (bp->b_addr)
1709 12501905636 : return bp->b_addr + offset;
1710 :
1711 0 : page = bp->b_pages[offset >> PAGE_SHIFT];
1712 0 : return page_address(page) + (offset & (PAGE_SIZE-1));
1713 : }
1714 :
1715 : void
1716 836874 : xfs_buf_zero(
1717 : struct xfs_buf *bp,
1718 : size_t boff,
1719 : size_t bsize)
1720 : {
1721 836874 : size_t bend;
1722 :
1723 836874 : bend = boff + bsize;
1724 1673736 : while (boff < bend) {
1725 836874 : struct page *page;
1726 836874 : int page_index, page_offset, csize;
1727 :
1728 836874 : page_index = (boff + bp->b_offset) >> PAGE_SHIFT;
1729 836874 : page_offset = (boff + bp->b_offset) & ~PAGE_MASK;
1730 836874 : page = bp->b_pages[page_index];
1731 836874 : csize = min_t(size_t, PAGE_SIZE - page_offset,
1732 : BBTOB(bp->b_length) - boff);
1733 :
1734 836874 : ASSERT((csize + page_offset) <= PAGE_SIZE);
1735 :
1736 836862 : memset(page_address(page) + page_offset, 0, csize);
1737 :
1738 836862 : boff += csize;
1739 : }
1740 836862 : }
1741 :
1742 : /*
1743 : * Log a message about and stale a buffer that a caller has decided is corrupt.
1744 : *
1745 : * This function should be called for the kinds of metadata corruption that
1746 : * cannot be detect from a verifier, such as incorrect inter-block relationship
1747 : * data. Do /not/ call this function from a verifier function.
1748 : *
1749 : * The buffer must be XBF_DONE prior to the call. Afterwards, the buffer will
1750 : * be marked stale, but b_error will not be set. The caller is responsible for
1751 : * releasing the buffer or fixing it.
1752 : */
1753 : void
1754 0 : __xfs_buf_mark_corrupt(
1755 : struct xfs_buf *bp,
1756 : xfs_failaddr_t fa)
1757 : {
1758 0 : ASSERT(bp->b_flags & XBF_DONE);
1759 :
1760 0 : xfs_buf_corruption_error(bp, fa);
1761 0 : xfs_buf_stale(bp);
1762 0 : }
1763 :
1764 : /*
1765 : * Handling of buffer targets (buftargs).
1766 : */
1767 :
1768 : /*
1769 : * Wait for any bufs with callbacks that have been submitted but have not yet
1770 : * returned. These buffers will have an elevated hold count, so wait on those
1771 : * while freeing all the buffers only held by the LRU.
1772 : */
1773 : static enum lru_status
1774 18842747 : xfs_buftarg_drain_rele(
1775 : struct list_head *item,
1776 : struct list_lru_one *lru,
1777 : spinlock_t *lru_lock,
1778 : void *arg)
1779 :
1780 : {
1781 18842747 : struct xfs_buf *bp = container_of(item, struct xfs_buf, b_lru);
1782 18842747 : struct list_head *dispose = arg;
1783 :
1784 18842747 : if (atomic_read(&bp->b_hold) > 1) {
1785 : /* need to wait, so skip it this pass */
1786 0 : trace_xfs_buf_drain_buftarg(bp, _RET_IP_);
1787 0 : return LRU_SKIP;
1788 : }
1789 18842747 : if (!spin_trylock(&bp->b_lock))
1790 : return LRU_SKIP;
1791 :
1792 : /*
1793 : * clear the LRU reference count so the buffer doesn't get
1794 : * ignored in xfs_buf_rele().
1795 : */
1796 18842747 : atomic_set(&bp->b_lru_ref, 0);
1797 18842747 : bp->b_state |= XFS_BSTATE_DISPOSE;
1798 18842747 : list_lru_isolate_move(lru, item, dispose);
1799 18842747 : spin_unlock(&bp->b_lock);
1800 18842747 : return LRU_REMOVED;
1801 : }
1802 :
1803 : /*
1804 : * Wait for outstanding I/O on the buftarg to complete.
1805 : */
1806 : void
1807 115997 : xfs_buftarg_wait(
1808 : struct xfs_buftarg *btp)
1809 : {
1810 : /*
1811 : * First wait on the buftarg I/O count for all in-flight buffers to be
1812 : * released. This is critical as new buffers do not make the LRU until
1813 : * they are released.
1814 : *
1815 : * Next, flush the buffer workqueue to ensure all completion processing
1816 : * has finished. Just waiting on buffer locks is not sufficient for
1817 : * async IO as the reference count held over IO is not released until
1818 : * after the buffer lock is dropped. Hence we need to ensure here that
1819 : * all reference counts have been dropped before we start walking the
1820 : * LRU list.
1821 : */
1822 119941 : while (percpu_counter_sum(&btp->bt_io_count))
1823 3944 : delay(100);
1824 115997 : flush_workqueue(btp->bt_mount->m_buf_workqueue);
1825 115997 : }
1826 :
1827 : void
1828 44993 : xfs_buftarg_drain(
1829 : struct xfs_buftarg *btp)
1830 : {
1831 44993 : LIST_HEAD(dispose);
1832 44993 : int loop = 0;
1833 44993 : bool write_fail = false;
1834 :
1835 44993 : xfs_buftarg_wait(btp);
1836 :
1837 : /* loop until there is nothing left on the lru list. */
1838 87787 : while (list_lru_count(&btp->bt_lru)) {
1839 42794 : list_lru_walk(&btp->bt_lru, xfs_buftarg_drain_rele,
1840 : &dispose, LONG_MAX);
1841 :
1842 18885541 : while (!list_empty(&dispose)) {
1843 18842747 : struct xfs_buf *bp;
1844 18842747 : bp = list_first_entry(&dispose, struct xfs_buf, b_lru);
1845 18842747 : list_del_init(&bp->b_lru);
1846 18842747 : if (bp->b_flags & XBF_WRITE_FAIL) {
1847 0 : write_fail = true;
1848 0 : xfs_buf_alert_ratelimited(bp,
1849 : "XFS: Corruption Alert",
1850 : "Corruption Alert: Buffer at daddr 0x%llx had permanent write failures!",
1851 : (long long)xfs_buf_daddr(bp));
1852 : }
1853 18842747 : xfs_buf_rele(bp);
1854 : }
1855 42794 : if (loop++ != 0)
1856 0 : delay(100);
1857 : }
1858 :
1859 : /*
1860 : * If one or more failed buffers were freed, that means dirty metadata
1861 : * was thrown away. This should only ever happen after I/O completion
1862 : * handling has elevated I/O error(s) to permanent failures and shuts
1863 : * down the journal.
1864 : */
1865 44993 : if (write_fail) {
1866 0 : ASSERT(xlog_is_shutdown(btp->bt_mount->m_log));
1867 0 : xfs_alert(btp->bt_mount,
1868 : "Please run xfs_repair to determine the extent of the problem.");
1869 : }
1870 44993 : }
1871 :
1872 : static enum lru_status
1873 25402059 : xfs_buftarg_isolate(
1874 : struct list_head *item,
1875 : struct list_lru_one *lru,
1876 : spinlock_t *lru_lock,
1877 : void *arg)
1878 : {
1879 25402059 : struct xfs_buf *bp = container_of(item, struct xfs_buf, b_lru);
1880 25402059 : struct list_head *dispose = arg;
1881 :
1882 : /*
1883 : * we are inverting the lru lock/bp->b_lock here, so use a trylock.
1884 : * If we fail to get the lock, just skip it.
1885 : */
1886 25402059 : if (!spin_trylock(&bp->b_lock))
1887 : return LRU_SKIP;
1888 : /*
1889 : * Decrement the b_lru_ref count unless the value is already
1890 : * zero. If the value is already zero, we need to reclaim the
1891 : * buffer, otherwise it gets another trip through the LRU.
1892 : */
1893 50804028 : if (atomic_add_unless(&bp->b_lru_ref, -1, 0)) {
1894 17196066 : spin_unlock(&bp->b_lock);
1895 17196066 : return LRU_ROTATE;
1896 : }
1897 :
1898 8205948 : bp->b_state |= XFS_BSTATE_DISPOSE;
1899 8205948 : list_lru_isolate_move(lru, item, dispose);
1900 8205948 : spin_unlock(&bp->b_lock);
1901 8205948 : return LRU_REMOVED;
1902 : }
1903 :
1904 : static unsigned long
1905 200923 : xfs_buftarg_shrink_scan(
1906 : struct shrinker *shrink,
1907 : struct shrink_control *sc)
1908 : {
1909 200923 : struct xfs_buftarg *btp = container_of(shrink,
1910 : struct xfs_buftarg, bt_shrinker);
1911 200923 : LIST_HEAD(dispose);
1912 200923 : unsigned long freed;
1913 :
1914 200923 : freed = list_lru_shrink_walk(&btp->bt_lru, sc,
1915 : xfs_buftarg_isolate, &dispose);
1916 :
1917 8406871 : while (!list_empty(&dispose)) {
1918 8205948 : struct xfs_buf *bp;
1919 8205948 : bp = list_first_entry(&dispose, struct xfs_buf, b_lru);
1920 8205948 : list_del_init(&bp->b_lru);
1921 8205948 : xfs_buf_rele(bp);
1922 : }
1923 :
1924 200923 : return freed;
1925 : }
1926 :
1927 : static unsigned long
1928 5405 : xfs_buftarg_shrink_count(
1929 : struct shrinker *shrink,
1930 : struct shrink_control *sc)
1931 : {
1932 5405 : struct xfs_buftarg *btp = container_of(shrink,
1933 : struct xfs_buftarg, bt_shrinker);
1934 5405 : return list_lru_shrink_count(&btp->bt_lru, sc);
1935 : }
1936 :
1937 : void
1938 22707 : xfs_free_buftarg(
1939 : struct xfs_buftarg *btp)
1940 : {
1941 22707 : unregister_shrinker(&btp->bt_shrinker);
1942 22707 : ASSERT(percpu_counter_sum(&btp->bt_io_count) == 0);
1943 22707 : percpu_counter_destroy(&btp->bt_io_count);
1944 22707 : list_lru_destroy(&btp->bt_lru);
1945 :
1946 22707 : blkdev_issue_flush(btp->bt_bdev);
1947 22707 : invalidate_bdev(btp->bt_bdev);
1948 22707 : fs_put_dax(btp->bt_daxdev, btp->bt_mount);
1949 :
1950 22707 : kmem_free(btp);
1951 22707 : }
1952 :
1953 : int
1954 45376 : xfs_setsize_buftarg(
1955 : xfs_buftarg_t *btp,
1956 : unsigned int sectorsize)
1957 : {
1958 : /* Set up metadata sector size info */
1959 45376 : btp->bt_meta_sectorsize = sectorsize;
1960 45376 : btp->bt_meta_sectormask = sectorsize - 1;
1961 :
1962 45376 : if (set_blocksize(btp->bt_bdev, sectorsize)) {
1963 0 : xfs_warn(btp->bt_mount,
1964 : "Cannot set_blocksize to %u on device %pg",
1965 : sectorsize, btp->bt_bdev);
1966 0 : return -EINVAL;
1967 : }
1968 :
1969 : /* Set up device logical sector size mask */
1970 45376 : btp->bt_logical_sectorsize = bdev_logical_block_size(btp->bt_bdev);
1971 45376 : btp->bt_logical_sectormask = bdev_logical_block_size(btp->bt_bdev) - 1;
1972 :
1973 45376 : return 0;
1974 : }
1975 :
1976 : /*
1977 : * When allocating the initial buffer target we have not yet
1978 : * read in the superblock, so don't know what sized sectors
1979 : * are being used at this early stage. Play safe.
1980 : */
1981 : STATIC int
1982 22704 : xfs_setsize_buftarg_early(
1983 : xfs_buftarg_t *btp,
1984 : struct block_device *bdev)
1985 : {
1986 45408 : return xfs_setsize_buftarg(btp, bdev_logical_block_size(bdev));
1987 : }
1988 :
1989 : struct xfs_buftarg *
1990 22704 : xfs_alloc_buftarg(
1991 : struct xfs_mount *mp,
1992 : struct block_device *bdev)
1993 : {
1994 22704 : xfs_buftarg_t *btp;
1995 22704 : const struct dax_holder_operations *ops = NULL;
1996 :
1997 : #if defined(CONFIG_FS_DAX) && defined(CONFIG_MEMORY_FAILURE)
1998 : ops = &xfs_dax_holder_operations;
1999 : #endif
2000 22704 : btp = kmem_zalloc(sizeof(*btp), KM_NOFS);
2001 :
2002 22704 : btp->bt_mount = mp;
2003 22704 : btp->bt_dev = bdev->bd_dev;
2004 22704 : btp->bt_bdev = bdev;
2005 22704 : btp->bt_daxdev = fs_dax_get_by_bdev(bdev, &btp->bt_dax_part_off,
2006 : mp, ops);
2007 :
2008 : /*
2009 : * Buffer IO error rate limiting. Limit it to no more than 10 messages
2010 : * per 30 seconds so as to not spam logs too much on repeated errors.
2011 : */
2012 22704 : ratelimit_state_init(&btp->bt_ioerror_rl, 30 * HZ,
2013 : DEFAULT_RATELIMIT_BURST);
2014 :
2015 22704 : if (xfs_setsize_buftarg_early(btp, bdev))
2016 0 : goto error_free;
2017 :
2018 22704 : if (list_lru_init(&btp->bt_lru))
2019 0 : goto error_free;
2020 :
2021 22704 : if (percpu_counter_init(&btp->bt_io_count, 0, GFP_KERNEL))
2022 0 : goto error_lru;
2023 :
2024 22704 : btp->bt_shrinker.count_objects = xfs_buftarg_shrink_count;
2025 22704 : btp->bt_shrinker.scan_objects = xfs_buftarg_shrink_scan;
2026 22704 : btp->bt_shrinker.seeks = DEFAULT_SEEKS;
2027 22704 : btp->bt_shrinker.flags = SHRINKER_NUMA_AWARE;
2028 22704 : if (register_shrinker(&btp->bt_shrinker, "xfs-buf:%s",
2029 22704 : mp->m_super->s_id))
2030 0 : goto error_pcpu;
2031 : return btp;
2032 :
2033 : error_pcpu:
2034 0 : percpu_counter_destroy(&btp->bt_io_count);
2035 0 : error_lru:
2036 0 : list_lru_destroy(&btp->bt_lru);
2037 0 : error_free:
2038 0 : kmem_free(btp);
2039 0 : return NULL;
2040 : }
2041 :
2042 : /*
2043 : * Cancel a delayed write list.
2044 : *
2045 : * Remove each buffer from the list, clear the delwri queue flag and drop the
2046 : * associated buffer reference.
2047 : */
2048 : void
2049 25391 : xfs_buf_delwri_cancel(
2050 : struct list_head *list)
2051 : {
2052 25391 : struct xfs_buf *bp;
2053 :
2054 25391 : while (!list_empty(list)) {
2055 0 : bp = list_first_entry(list, struct xfs_buf, b_list);
2056 :
2057 0 : xfs_buf_lock(bp);
2058 0 : bp->b_flags &= ~_XBF_DELWRI_Q;
2059 0 : list_del_init(&bp->b_list);
2060 0 : xfs_buf_relse(bp);
2061 : }
2062 25391 : }
2063 :
2064 : /*
2065 : * Add a buffer to the delayed write list.
2066 : *
2067 : * This queues a buffer for writeout if it hasn't already been. Note that
2068 : * neither this routine nor the buffer list submission functions perform
2069 : * any internal synchronization. It is expected that the lists are thread-local
2070 : * to the callers.
2071 : *
2072 : * Returns true if we queued up the buffer, or false if it already had
2073 : * been on the buffer list.
2074 : */
2075 : bool
2076 78514914 : xfs_buf_delwri_queue(
2077 : struct xfs_buf *bp,
2078 : struct list_head *list)
2079 : {
2080 78514914 : ASSERT(xfs_buf_islocked(bp));
2081 78514914 : ASSERT(!(bp->b_flags & XBF_READ));
2082 :
2083 : /*
2084 : * If the buffer is already marked delwri it already is queued up
2085 : * by someone else for imediate writeout. Just ignore it in that
2086 : * case.
2087 : */
2088 78514914 : if (bp->b_flags & _XBF_DELWRI_Q) {
2089 7928215 : trace_xfs_buf_delwri_queued(bp, _RET_IP_);
2090 7928215 : return false;
2091 : }
2092 :
2093 70586699 : trace_xfs_buf_delwri_queue(bp, _RET_IP_);
2094 :
2095 : /*
2096 : * If a buffer gets written out synchronously or marked stale while it
2097 : * is on a delwri list we lazily remove it. To do this, the other party
2098 : * clears the _XBF_DELWRI_Q flag but otherwise leaves the buffer alone.
2099 : * It remains referenced and on the list. In a rare corner case it
2100 : * might get readded to a delwri list after the synchronous writeout, in
2101 : * which case we need just need to re-add the flag here.
2102 : */
2103 70586693 : bp->b_flags |= _XBF_DELWRI_Q;
2104 70586693 : if (list_empty(&bp->b_list)) {
2105 70586684 : atomic_inc(&bp->b_hold);
2106 70586652 : list_add_tail(&bp->b_list, list);
2107 : }
2108 :
2109 : return true;
2110 : }
2111 :
2112 : /*
2113 : * Compare function is more complex than it needs to be because
2114 : * the return value is only 32 bits and we are doing comparisons
2115 : * on 64 bit values
2116 : */
2117 : static int
2118 580201283 : xfs_buf_cmp(
2119 : void *priv,
2120 : const struct list_head *a,
2121 : const struct list_head *b)
2122 : {
2123 580201283 : struct xfs_buf *ap = container_of(a, struct xfs_buf, b_list);
2124 580201283 : struct xfs_buf *bp = container_of(b, struct xfs_buf, b_list);
2125 580201283 : xfs_daddr_t diff;
2126 :
2127 580201283 : diff = ap->b_maps[0].bm_bn - bp->b_maps[0].bm_bn;
2128 580201283 : if (diff < 0)
2129 : return -1;
2130 287613590 : if (diff > 0)
2131 287613095 : return 1;
2132 : return 0;
2133 : }
2134 :
2135 : /*
2136 : * Submit buffers for write. If wait_list is specified, the buffers are
2137 : * submitted using sync I/O and placed on the wait list such that the caller can
2138 : * iowait each buffer. Otherwise async I/O is used and the buffers are released
2139 : * at I/O completion time. In either case, buffers remain locked until I/O
2140 : * completes and the buffer is released from the queue.
2141 : */
2142 : static int
2143 2737539 : xfs_buf_delwri_submit_buffers(
2144 : struct list_head *buffer_list,
2145 : struct list_head *wait_list)
2146 : {
2147 2737539 : struct xfs_buf *bp, *n;
2148 2737539 : int pinned = 0;
2149 2737539 : struct blk_plug plug;
2150 :
2151 2737539 : list_sort(NULL, buffer_list, xfs_buf_cmp);
2152 :
2153 2737532 : blk_start_plug(&plug);
2154 74095724 : list_for_each_entry_safe(bp, n, buffer_list, b_list) {
2155 71358199 : if (!wait_list) {
2156 53066097 : if (!xfs_buf_trylock(bp))
2157 41793 : continue;
2158 53024305 : if (xfs_buf_ispinned(bp)) {
2159 729653 : xfs_buf_unlock(bp);
2160 729653 : pinned++;
2161 729653 : continue;
2162 : }
2163 : } else {
2164 18292102 : xfs_buf_lock(bp);
2165 : }
2166 :
2167 : /*
2168 : * Someone else might have written the buffer synchronously or
2169 : * marked it stale in the meantime. In that case only the
2170 : * _XBF_DELWRI_Q flag got cleared, and we have to drop the
2171 : * reference and remove it from the list here.
2172 : */
2173 70586750 : if (!(bp->b_flags & _XBF_DELWRI_Q)) {
2174 22552 : list_del_init(&bp->b_list);
2175 22552 : xfs_buf_relse(bp);
2176 22552 : continue;
2177 : }
2178 :
2179 70564198 : trace_xfs_buf_delwri_split(bp, _RET_IP_);
2180 :
2181 : /*
2182 : * If we have a wait list, each buffer (and associated delwri
2183 : * queue reference) transfers to it and is submitted
2184 : * synchronously. Otherwise, drop the buffer from the delwri
2185 : * queue and submit async.
2186 : */
2187 70564202 : bp->b_flags &= ~_XBF_DELWRI_Q;
2188 70564202 : bp->b_flags |= XBF_WRITE;
2189 70564202 : if (wait_list) {
2190 18292102 : bp->b_flags &= ~XBF_ASYNC;
2191 18292102 : list_move_tail(&bp->b_list, wait_list);
2192 : } else {
2193 52272100 : bp->b_flags |= XBF_ASYNC;
2194 52272100 : list_del_init(&bp->b_list);
2195 : }
2196 70564202 : __xfs_buf_submit(bp, false);
2197 : }
2198 2737525 : blk_finish_plug(&plug);
2199 :
2200 2737528 : return pinned;
2201 : }
2202 :
2203 : /*
2204 : * Write out a buffer list asynchronously.
2205 : *
2206 : * This will take the @buffer_list, write all non-locked and non-pinned buffers
2207 : * out and not wait for I/O completion on any of the buffers. This interface
2208 : * is only safely useable for callers that can track I/O completion by higher
2209 : * level means, e.g. AIL pushing as the @buffer_list is consumed in this
2210 : * function.
2211 : *
2212 : * Note: this function will skip buffers it would block on, and in doing so
2213 : * leaves them on @buffer_list so they can be retried on a later pass. As such,
2214 : * it is up to the caller to ensure that the buffer list is fully submitted or
2215 : * cancelled appropriately when they are finished with the list. Failure to
2216 : * cancel or resubmit the list until it is empty will result in leaked buffers
2217 : * at unmount time.
2218 : */
2219 : int
2220 1936395 : xfs_buf_delwri_submit_nowait(
2221 : struct list_head *buffer_list)
2222 : {
2223 1936395 : return xfs_buf_delwri_submit_buffers(buffer_list, NULL);
2224 : }
2225 :
2226 : /*
2227 : * Write out a buffer list synchronously.
2228 : *
2229 : * This will take the @buffer_list, write all buffers out and wait for I/O
2230 : * completion on all of the buffers. @buffer_list is consumed by the function,
2231 : * so callers must have some other way of tracking buffers if they require such
2232 : * functionality.
2233 : */
2234 : int
2235 801139 : xfs_buf_delwri_submit(
2236 : struct list_head *buffer_list)
2237 : {
2238 801139 : LIST_HEAD (wait_list);
2239 801139 : int error = 0, error2;
2240 801139 : struct xfs_buf *bp;
2241 :
2242 801139 : xfs_buf_delwri_submit_buffers(buffer_list, &wait_list);
2243 :
2244 : /* Wait for IO to complete. */
2245 19093241 : while (!list_empty(&wait_list)) {
2246 18292102 : bp = list_first_entry(&wait_list, struct xfs_buf, b_list);
2247 :
2248 18292102 : list_del_init(&bp->b_list);
2249 :
2250 : /*
2251 : * Wait on the locked buffer, check for errors and unlock and
2252 : * release the delwri queue reference.
2253 : */
2254 18292102 : error2 = xfs_buf_iowait(bp);
2255 18292102 : xfs_buf_relse(bp);
2256 18292102 : if (!error)
2257 18292102 : error = error2;
2258 : }
2259 :
2260 801139 : return error;
2261 : }
2262 :
2263 : /*
2264 : * Push a single buffer on a delwri queue.
2265 : *
2266 : * The purpose of this function is to submit a single buffer of a delwri queue
2267 : * and return with the buffer still on the original queue. The waiting delwri
2268 : * buffer submission infrastructure guarantees transfer of the delwri queue
2269 : * buffer reference to a temporary wait list. We reuse this infrastructure to
2270 : * transfer the buffer back to the original queue.
2271 : *
2272 : * Note the buffer transitions from the queued state, to the submitted and wait
2273 : * listed state and back to the queued state during this call. The buffer
2274 : * locking and queue management logic between _delwri_pushbuf() and
2275 : * _delwri_queue() guarantee that the buffer cannot be queued to another list
2276 : * before returning.
2277 : */
2278 : int
2279 0 : xfs_buf_delwri_pushbuf(
2280 : struct xfs_buf *bp,
2281 : struct list_head *buffer_list)
2282 : {
2283 0 : LIST_HEAD (submit_list);
2284 0 : int error;
2285 :
2286 0 : ASSERT(bp->b_flags & _XBF_DELWRI_Q);
2287 :
2288 0 : trace_xfs_buf_delwri_pushbuf(bp, _RET_IP_);
2289 :
2290 : /*
2291 : * Isolate the buffer to a new local list so we can submit it for I/O
2292 : * independently from the rest of the original list.
2293 : */
2294 0 : xfs_buf_lock(bp);
2295 0 : list_move(&bp->b_list, &submit_list);
2296 0 : xfs_buf_unlock(bp);
2297 :
2298 : /*
2299 : * Delwri submission clears the DELWRI_Q buffer flag and returns with
2300 : * the buffer on the wait list with the original reference. Rather than
2301 : * bounce the buffer from a local wait list back to the original list
2302 : * after I/O completion, reuse the original list as the wait list.
2303 : */
2304 0 : xfs_buf_delwri_submit_buffers(&submit_list, buffer_list);
2305 :
2306 : /*
2307 : * The buffer is now locked, under I/O and wait listed on the original
2308 : * delwri queue. Wait for I/O completion, restore the DELWRI_Q flag and
2309 : * return with the buffer unlocked and on the original queue.
2310 : */
2311 0 : error = xfs_buf_iowait(bp);
2312 0 : bp->b_flags |= _XBF_DELWRI_Q;
2313 0 : xfs_buf_unlock(bp);
2314 :
2315 0 : return error;
2316 : }
2317 :
2318 11456457708 : void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref)
2319 : {
2320 : /*
2321 : * Set the lru reference count to 0 based on the error injection tag.
2322 : * This allows userspace to disrupt buffer caching for debug/testing
2323 : * purposes.
2324 : */
2325 11456457708 : if (XFS_TEST_ERROR(false, bp->b_mount, XFS_ERRTAG_BUF_LRU_REF))
2326 10 : lru_ref = 0;
2327 :
2328 11459640519 : atomic_set(&bp->b_lru_ref, lru_ref);
2329 11459640519 : }
2330 :
2331 : /*
2332 : * Verify an on-disk magic value against the magic value specified in the
2333 : * verifier structure. The verifier magic is in disk byte order so the caller is
2334 : * expected to pass the value directly from disk.
2335 : */
2336 : bool
2337 171373407 : xfs_verify_magic(
2338 : struct xfs_buf *bp,
2339 : __be32 dmagic)
2340 : {
2341 171373407 : struct xfs_mount *mp = bp->b_mount;
2342 171373407 : int idx;
2343 :
2344 171373407 : idx = xfs_has_crc(mp);
2345 171373407 : if (WARN_ON(!bp->b_ops || !bp->b_ops->magic[idx]))
2346 : return false;
2347 171376532 : return dmagic == bp->b_ops->magic[idx];
2348 : }
2349 : /*
2350 : * Verify an on-disk magic value against the magic value specified in the
2351 : * verifier structure. The verifier magic is in disk byte order so the caller is
2352 : * expected to pass the value directly from disk.
2353 : */
2354 : bool
2355 1090723068 : xfs_verify_magic16(
2356 : struct xfs_buf *bp,
2357 : __be16 dmagic)
2358 : {
2359 1090723068 : struct xfs_mount *mp = bp->b_mount;
2360 1090723068 : int idx;
2361 :
2362 1090723068 : idx = xfs_has_crc(mp);
2363 1090723068 : if (WARN_ON(!bp->b_ops || !bp->b_ops->magic16[idx]))
2364 : return false;
2365 1090725272 : return dmagic == bp->b_ops->magic16[idx];
2366 : }
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