1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
4 * Copyright (c) 2016-2018 Christoph Hellwig.
5 * All Rights Reserved.
6 */
7#include "xfs.h"
8#include "xfs_fs.h"
9#include "xfs_shared.h"
10#include "xfs_format.h"
11#include "xfs_log_format.h"
12#include "xfs_trans_resv.h"
13#include "xfs_mount.h"
14#include "xfs_inode.h"
15#include "xfs_btree.h"
16#include "xfs_bmap_btree.h"
17#include "xfs_bmap.h"
18#include "xfs_bmap_util.h"
19#include "xfs_errortag.h"
20#include "xfs_error.h"
21#include "xfs_trans.h"
22#include "xfs_trans_space.h"
23#include "xfs_inode_item.h"
24#include "xfs_iomap.h"
25#include "xfs_trace.h"
26#include "xfs_quota.h"
27#include "xfs_dquot_item.h"
28#include "xfs_dquot.h"
29#include "xfs_reflink.h"
30#include "xfs_health.h"
31
32#define XFS_ALLOC_ALIGN(mp, off) \
33 (((off) >> mp->m_allocsize_log) << mp->m_allocsize_log)
34
35static int
36xfs_alert_fsblock_zero(
37 xfs_inode_t *ip,
38 xfs_bmbt_irec_t *imap)
39{
40 xfs_alert_tag(ip->i_mount, XFS_PTAG_FSBLOCK_ZERO,
41 "Access to block zero in inode %llu "
42 "start_block: %llx start_off: %llx "
43 "blkcnt: %llx extent-state: %x",
44 (unsigned long long)ip->i_ino,
45 (unsigned long long)imap->br_startblock,
46 (unsigned long long)imap->br_startoff,
47 (unsigned long long)imap->br_blockcount,
48 imap->br_state);
49 xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
50 return -EFSCORRUPTED;
51}
52
53u64
54xfs_iomap_inode_sequence(
55 struct xfs_inode *ip,
56 u16 iomap_flags)
57{
58 u64 cookie = 0;
59
60 if (iomap_flags & IOMAP_F_XATTR)
61 return READ_ONCE(ip->i_af.if_seq);
62 if ((iomap_flags & IOMAP_F_SHARED) && ip->i_cowfp)
63 cookie = (u64)READ_ONCE(ip->i_cowfp->if_seq) << 32;
64 return cookie | READ_ONCE(ip->i_df.if_seq);
65}
66
67/*
68 * Check that the iomap passed to us is still valid for the given offset and
69 * length.
70 */
71static bool
72xfs_iomap_valid(
73 struct inode *inode,
74 const struct iomap *iomap)
75{
76 struct xfs_inode *ip = XFS_I(inode);
77
78 if (iomap->validity_cookie !=
79 xfs_iomap_inode_sequence(ip, iomap_flags: iomap->flags)) {
80 trace_xfs_iomap_invalid(ip, iomap);
81 return false;
82 }
83
84 XFS_ERRORTAG_DELAY(ip->i_mount, XFS_ERRTAG_WRITE_DELAY_MS);
85 return true;
86}
87
88static const struct iomap_folio_ops xfs_iomap_folio_ops = {
89 .iomap_valid = xfs_iomap_valid,
90};
91
92int
93xfs_bmbt_to_iomap(
94 struct xfs_inode *ip,
95 struct iomap *iomap,
96 struct xfs_bmbt_irec *imap,
97 unsigned int mapping_flags,
98 u16 iomap_flags,
99 u64 sequence_cookie)
100{
101 struct xfs_mount *mp = ip->i_mount;
102 struct xfs_buftarg *target = xfs_inode_buftarg(ip);
103
104 if (unlikely(!xfs_valid_startblock(ip, imap->br_startblock))) {
105 xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
106 return xfs_alert_fsblock_zero(ip, imap);
107 }
108
109 if (imap->br_startblock == HOLESTARTBLOCK) {
110 iomap->addr = IOMAP_NULL_ADDR;
111 iomap->type = IOMAP_HOLE;
112 } else if (imap->br_startblock == DELAYSTARTBLOCK ||
113 isnullstartblock(imap->br_startblock)) {
114 iomap->addr = IOMAP_NULL_ADDR;
115 iomap->type = IOMAP_DELALLOC;
116 } else {
117 iomap->addr = BBTOB(xfs_fsb_to_db(ip, imap->br_startblock));
118 if (mapping_flags & IOMAP_DAX)
119 iomap->addr += target->bt_dax_part_off;
120
121 if (imap->br_state == XFS_EXT_UNWRITTEN)
122 iomap->type = IOMAP_UNWRITTEN;
123 else
124 iomap->type = IOMAP_MAPPED;
125
126 }
127 iomap->offset = XFS_FSB_TO_B(mp, imap->br_startoff);
128 iomap->length = XFS_FSB_TO_B(mp, imap->br_blockcount);
129 if (mapping_flags & IOMAP_DAX)
130 iomap->dax_dev = target->bt_daxdev;
131 else
132 iomap->bdev = target->bt_bdev;
133 iomap->flags = iomap_flags;
134
135 if (xfs_ipincount(ip) &&
136 (ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
137 iomap->flags |= IOMAP_F_DIRTY;
138
139 iomap->validity_cookie = sequence_cookie;
140 iomap->folio_ops = &xfs_iomap_folio_ops;
141 return 0;
142}
143
144static void
145xfs_hole_to_iomap(
146 struct xfs_inode *ip,
147 struct iomap *iomap,
148 xfs_fileoff_t offset_fsb,
149 xfs_fileoff_t end_fsb)
150{
151 struct xfs_buftarg *target = xfs_inode_buftarg(ip);
152
153 iomap->addr = IOMAP_NULL_ADDR;
154 iomap->type = IOMAP_HOLE;
155 iomap->offset = XFS_FSB_TO_B(ip->i_mount, offset_fsb);
156 iomap->length = XFS_FSB_TO_B(ip->i_mount, end_fsb - offset_fsb);
157 iomap->bdev = target->bt_bdev;
158 iomap->dax_dev = target->bt_daxdev;
159}
160
161static inline xfs_fileoff_t
162xfs_iomap_end_fsb(
163 struct xfs_mount *mp,
164 loff_t offset,
165 loff_t count)
166{
167 ASSERT(offset <= mp->m_super->s_maxbytes);
168 return min(XFS_B_TO_FSB(mp, offset + count),
169 XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
170}
171
172static xfs_extlen_t
173xfs_eof_alignment(
174 struct xfs_inode *ip)
175{
176 struct xfs_mount *mp = ip->i_mount;
177 xfs_extlen_t align = 0;
178
179 if (!XFS_IS_REALTIME_INODE(ip)) {
180 /*
181 * Round up the allocation request to a stripe unit
182 * (m_dalign) boundary if the file size is >= stripe unit
183 * size, and we are allocating past the allocation eof.
184 *
185 * If mounted with the "-o swalloc" option the alignment is
186 * increased from the strip unit size to the stripe width.
187 */
188 if (mp->m_swidth && xfs_has_swalloc(mp))
189 align = mp->m_swidth;
190 else if (mp->m_dalign)
191 align = mp->m_dalign;
192
193 if (align && XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, align))
194 align = 0;
195 }
196
197 return align;
198}
199
200/*
201 * Check if last_fsb is outside the last extent, and if so grow it to the next
202 * stripe unit boundary.
203 */
204xfs_fileoff_t
205xfs_iomap_eof_align_last_fsb(
206 struct xfs_inode *ip,
207 xfs_fileoff_t end_fsb)
208{
209 struct xfs_ifork *ifp = xfs_ifork_ptr(ip, XFS_DATA_FORK);
210 xfs_extlen_t extsz = xfs_get_extsz_hint(ip);
211 xfs_extlen_t align = xfs_eof_alignment(ip);
212 struct xfs_bmbt_irec irec;
213 struct xfs_iext_cursor icur;
214
215 ASSERT(!xfs_need_iread_extents(ifp));
216
217 /*
218 * Always round up the allocation request to the extent hint boundary.
219 */
220 if (extsz) {
221 if (align)
222 align = roundup_64(align, extsz);
223 else
224 align = extsz;
225 }
226
227 if (align) {
228 xfs_fileoff_t aligned_end_fsb = roundup_64(end_fsb, align);
229
230 xfs_iext_last(ifp, &icur);
231 if (!xfs_iext_get_extent(ifp, &icur, &irec) ||
232 aligned_end_fsb >= irec.br_startoff + irec.br_blockcount)
233 return aligned_end_fsb;
234 }
235
236 return end_fsb;
237}
238
239int
240xfs_iomap_write_direct(
241 struct xfs_inode *ip,
242 xfs_fileoff_t offset_fsb,
243 xfs_fileoff_t count_fsb,
244 unsigned int flags,
245 struct xfs_bmbt_irec *imap,
246 u64 *seq)
247{
248 struct xfs_mount *mp = ip->i_mount;
249 struct xfs_trans *tp;
250 xfs_filblks_t resaligned;
251 int nimaps;
252 unsigned int dblocks, rblocks;
253 bool force = false;
254 int error;
255 int bmapi_flags = XFS_BMAPI_PREALLOC;
256 int nr_exts = XFS_IEXT_ADD_NOSPLIT_CNT;
257
258 ASSERT(count_fsb > 0);
259
260 resaligned = xfs_aligned_fsb_count(offset_fsb, count_fsb,
261 xfs_get_extsz_hint(ip));
262 if (unlikely(XFS_IS_REALTIME_INODE(ip))) {
263 dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
264 rblocks = resaligned;
265 } else {
266 dblocks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
267 rblocks = 0;
268 }
269
270 error = xfs_qm_dqattach(ip);
271 if (error)
272 return error;
273
274 /*
275 * For DAX, we do not allocate unwritten extents, but instead we zero
276 * the block before we commit the transaction. Ideally we'd like to do
277 * this outside the transaction context, but if we commit and then crash
278 * we may not have zeroed the blocks and this will be exposed on
279 * recovery of the allocation. Hence we must zero before commit.
280 *
281 * Further, if we are mapping unwritten extents here, we need to zero
282 * and convert them to written so that we don't need an unwritten extent
283 * callback for DAX. This also means that we need to be able to dip into
284 * the reserve block pool for bmbt block allocation if there is no space
285 * left but we need to do unwritten extent conversion.
286 */
287 if (flags & IOMAP_DAX) {
288 bmapi_flags = XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO;
289 if (imap->br_state == XFS_EXT_UNWRITTEN) {
290 force = true;
291 nr_exts = XFS_IEXT_WRITE_UNWRITTEN_CNT;
292 dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
293 }
294 }
295
296 error = xfs_trans_alloc_inode(ip, resv: &M_RES(mp)->tr_write, dblocks,
297 rblocks, force, tpp: &tp);
298 if (error)
299 return error;
300
301 error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK, nr_exts);
302 if (error == -EFBIG)
303 error = xfs_iext_count_upgrade(tp, ip, nr_exts);
304 if (error)
305 goto out_trans_cancel;
306
307 /*
308 * From this point onwards we overwrite the imap pointer that the
309 * caller gave to us.
310 */
311 nimaps = 1;
312 error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb, bmapi_flags, 0,
313 imap, &nimaps);
314 if (error)
315 goto out_trans_cancel;
316
317 /*
318 * Complete the transaction
319 */
320 error = xfs_trans_commit(tp);
321 if (error)
322 goto out_unlock;
323
324 /*
325 * Copy any maps to caller's array and return any error.
326 */
327 if (nimaps == 0) {
328 error = -ENOSPC;
329 goto out_unlock;
330 }
331
332 if (unlikely(!xfs_valid_startblock(ip, imap->br_startblock))) {
333 xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
334 error = xfs_alert_fsblock_zero(ip, imap);
335 }
336
337out_unlock:
338 *seq = xfs_iomap_inode_sequence(ip, iomap_flags: 0);
339 xfs_iunlock(ip, XFS_ILOCK_EXCL);
340 return error;
341
342out_trans_cancel:
343 xfs_trans_cancel(tp);
344 goto out_unlock;
345}
346
347STATIC bool
348xfs_quota_need_throttle(
349 struct xfs_inode *ip,
350 xfs_dqtype_t type,
351 xfs_fsblock_t alloc_blocks)
352{
353 struct xfs_dquot *dq = xfs_inode_dquot(ip, type);
354
355 if (!dq || !xfs_this_quota_on(ip->i_mount, type))
356 return false;
357
358 /* no hi watermark, no throttle */
359 if (!dq->q_prealloc_hi_wmark)
360 return false;
361
362 /* under the lo watermark, no throttle */
363 if (dq->q_blk.reserved + alloc_blocks < dq->q_prealloc_lo_wmark)
364 return false;
365
366 return true;
367}
368
369STATIC void
370xfs_quota_calc_throttle(
371 struct xfs_inode *ip,
372 xfs_dqtype_t type,
373 xfs_fsblock_t *qblocks,
374 int *qshift,
375 int64_t *qfreesp)
376{
377 struct xfs_dquot *dq = xfs_inode_dquot(ip, type);
378 int64_t freesp;
379 int shift = 0;
380
381 /* no dq, or over hi wmark, squash the prealloc completely */
382 if (!dq || dq->q_blk.reserved >= dq->q_prealloc_hi_wmark) {
383 *qblocks = 0;
384 *qfreesp = 0;
385 return;
386 }
387
388 freesp = dq->q_prealloc_hi_wmark - dq->q_blk.reserved;
389 if (freesp < dq->q_low_space[XFS_QLOWSP_5_PCNT]) {
390 shift = 2;
391 if (freesp < dq->q_low_space[XFS_QLOWSP_3_PCNT])
392 shift += 2;
393 if (freesp < dq->q_low_space[XFS_QLOWSP_1_PCNT])
394 shift += 2;
395 }
396
397 if (freesp < *qfreesp)
398 *qfreesp = freesp;
399
400 /* only overwrite the throttle values if we are more aggressive */
401 if ((freesp >> shift) < (*qblocks >> *qshift)) {
402 *qblocks = freesp;
403 *qshift = shift;
404 }
405}
406
407/*
408 * If we don't have a user specified preallocation size, dynamically increase
409 * the preallocation size as the size of the file grows. Cap the maximum size
410 * at a single extent or less if the filesystem is near full. The closer the
411 * filesystem is to being full, the smaller the maximum preallocation.
412 */
413STATIC xfs_fsblock_t
414xfs_iomap_prealloc_size(
415 struct xfs_inode *ip,
416 int whichfork,
417 loff_t offset,
418 loff_t count,
419 struct xfs_iext_cursor *icur)
420{
421 struct xfs_iext_cursor ncur = *icur;
422 struct xfs_bmbt_irec prev, got;
423 struct xfs_mount *mp = ip->i_mount;
424 struct xfs_ifork *ifp = xfs_ifork_ptr(ip, whichfork);
425 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
426 int64_t freesp;
427 xfs_fsblock_t qblocks;
428 xfs_fsblock_t alloc_blocks = 0;
429 xfs_extlen_t plen;
430 int shift = 0;
431 int qshift = 0;
432
433 /*
434 * As an exception we don't do any preallocation at all if the file is
435 * smaller than the minimum preallocation and we are using the default
436 * dynamic preallocation scheme, as it is likely this is the only write
437 * to the file that is going to be done.
438 */
439 if (XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_allocsize_blocks))
440 return 0;
441
442 /*
443 * Use the minimum preallocation size for small files or if we are
444 * writing right after a hole.
445 */
446 if (XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_dalign) ||
447 !xfs_iext_prev_extent(ifp, &ncur, &prev) ||
448 prev.br_startoff + prev.br_blockcount < offset_fsb)
449 return mp->m_allocsize_blocks;
450
451 /*
452 * Take the size of the preceding data extents as the basis for the
453 * preallocation size. Note that we don't care if the previous extents
454 * are written or not.
455 */
456 plen = prev.br_blockcount;
457 while (xfs_iext_prev_extent(ifp, &ncur, &got)) {
458 if (plen > XFS_MAX_BMBT_EXTLEN / 2 ||
459 isnullstartblock(got.br_startblock) ||
460 got.br_startoff + got.br_blockcount != prev.br_startoff ||
461 got.br_startblock + got.br_blockcount != prev.br_startblock)
462 break;
463 plen += got.br_blockcount;
464 prev = got;
465 }
466
467 /*
468 * If the size of the extents is greater than half the maximum extent
469 * length, then use the current offset as the basis. This ensures that
470 * for large files the preallocation size always extends to
471 * XFS_BMBT_MAX_EXTLEN rather than falling short due to things like stripe
472 * unit/width alignment of real extents.
473 */
474 alloc_blocks = plen * 2;
475 if (alloc_blocks > XFS_MAX_BMBT_EXTLEN)
476 alloc_blocks = XFS_B_TO_FSB(mp, offset);
477 qblocks = alloc_blocks;
478
479 /*
480 * XFS_BMBT_MAX_EXTLEN is not a power of two value but we round the prealloc
481 * down to the nearest power of two value after throttling. To prevent
482 * the round down from unconditionally reducing the maximum supported
483 * prealloc size, we round up first, apply appropriate throttling, round
484 * down and cap the value to XFS_BMBT_MAX_EXTLEN.
485 */
486 alloc_blocks = XFS_FILEOFF_MIN(roundup_pow_of_two(XFS_MAX_BMBT_EXTLEN),
487 alloc_blocks);
488
489 freesp = percpu_counter_read_positive(fbc: &mp->m_fdblocks);
490 if (freesp < mp->m_low_space[XFS_LOWSP_5_PCNT]) {
491 shift = 2;
492 if (freesp < mp->m_low_space[XFS_LOWSP_4_PCNT])
493 shift++;
494 if (freesp < mp->m_low_space[XFS_LOWSP_3_PCNT])
495 shift++;
496 if (freesp < mp->m_low_space[XFS_LOWSP_2_PCNT])
497 shift++;
498 if (freesp < mp->m_low_space[XFS_LOWSP_1_PCNT])
499 shift++;
500 }
501
502 /*
503 * Check each quota to cap the prealloc size, provide a shift value to
504 * throttle with and adjust amount of available space.
505 */
506 if (xfs_quota_need_throttle(ip, XFS_DQTYPE_USER, alloc_blocks))
507 xfs_quota_calc_throttle(ip, XFS_DQTYPE_USER, &qblocks, &qshift,
508 &freesp);
509 if (xfs_quota_need_throttle(ip, XFS_DQTYPE_GROUP, alloc_blocks))
510 xfs_quota_calc_throttle(ip, XFS_DQTYPE_GROUP, &qblocks, &qshift,
511 &freesp);
512 if (xfs_quota_need_throttle(ip, XFS_DQTYPE_PROJ, alloc_blocks))
513 xfs_quota_calc_throttle(ip, XFS_DQTYPE_PROJ, &qblocks, &qshift,
514 &freesp);
515
516 /*
517 * The final prealloc size is set to the minimum of free space available
518 * in each of the quotas and the overall filesystem.
519 *
520 * The shift throttle value is set to the maximum value as determined by
521 * the global low free space values and per-quota low free space values.
522 */
523 alloc_blocks = min(alloc_blocks, qblocks);
524 shift = max(shift, qshift);
525
526 if (shift)
527 alloc_blocks >>= shift;
528 /*
529 * rounddown_pow_of_two() returns an undefined result if we pass in
530 * alloc_blocks = 0.
531 */
532 if (alloc_blocks)
533 alloc_blocks = rounddown_pow_of_two(alloc_blocks);
534 if (alloc_blocks > XFS_MAX_BMBT_EXTLEN)
535 alloc_blocks = XFS_MAX_BMBT_EXTLEN;
536
537 /*
538 * If we are still trying to allocate more space than is
539 * available, squash the prealloc hard. This can happen if we
540 * have a large file on a small filesystem and the above
541 * lowspace thresholds are smaller than XFS_BMBT_MAX_EXTLEN.
542 */
543 while (alloc_blocks && alloc_blocks >= freesp)
544 alloc_blocks >>= 4;
545 if (alloc_blocks < mp->m_allocsize_blocks)
546 alloc_blocks = mp->m_allocsize_blocks;
547 trace_xfs_iomap_prealloc_size(ip, alloc_blocks, shift,
548 mp->m_allocsize_blocks);
549 return alloc_blocks;
550}
551
552int
553xfs_iomap_write_unwritten(
554 xfs_inode_t *ip,
555 xfs_off_t offset,
556 xfs_off_t count,
557 bool update_isize)
558{
559 xfs_mount_t *mp = ip->i_mount;
560 xfs_fileoff_t offset_fsb;
561 xfs_filblks_t count_fsb;
562 xfs_filblks_t numblks_fsb;
563 int nimaps;
564 xfs_trans_t *tp;
565 xfs_bmbt_irec_t imap;
566 struct inode *inode = VFS_I(ip);
567 xfs_fsize_t i_size;
568 uint resblks;
569 int error;
570
571 trace_xfs_unwritten_convert(ip, offset, count);
572
573 offset_fsb = XFS_B_TO_FSBT(mp, offset);
574 count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
575 count_fsb = (xfs_filblks_t)(count_fsb - offset_fsb);
576
577 /*
578 * Reserve enough blocks in this transaction for two complete extent
579 * btree splits. We may be converting the middle part of an unwritten
580 * extent and in this case we will insert two new extents in the btree
581 * each of which could cause a full split.
582 *
583 * This reservation amount will be used in the first call to
584 * xfs_bmbt_split() to select an AG with enough space to satisfy the
585 * rest of the operation.
586 */
587 resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
588
589 /* Attach dquots so that bmbt splits are accounted correctly. */
590 error = xfs_qm_dqattach(ip);
591 if (error)
592 return error;
593
594 do {
595 /*
596 * Set up a transaction to convert the range of extents
597 * from unwritten to real. Do allocations in a loop until
598 * we have covered the range passed in.
599 *
600 * Note that we can't risk to recursing back into the filesystem
601 * here as we might be asked to write out the same inode that we
602 * complete here and might deadlock on the iolock.
603 */
604 error = xfs_trans_alloc_inode(ip, resv: &M_RES(mp)->tr_write, dblocks: resblks,
605 rblocks: 0, force: true, tpp: &tp);
606 if (error)
607 return error;
608
609 error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
610 XFS_IEXT_WRITE_UNWRITTEN_CNT);
611 if (error == -EFBIG)
612 error = xfs_iext_count_upgrade(tp, ip,
613 XFS_IEXT_WRITE_UNWRITTEN_CNT);
614 if (error)
615 goto error_on_bmapi_transaction;
616
617 /*
618 * Modify the unwritten extent state of the buffer.
619 */
620 nimaps = 1;
621 error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb,
622 XFS_BMAPI_CONVERT, resblks, &imap,
623 &nimaps);
624 if (error)
625 goto error_on_bmapi_transaction;
626
627 /*
628 * Log the updated inode size as we go. We have to be careful
629 * to only log it up to the actual write offset if it is
630 * halfway into a block.
631 */
632 i_size = XFS_FSB_TO_B(mp, offset_fsb + count_fsb);
633 if (i_size > offset + count)
634 i_size = offset + count;
635 if (update_isize && i_size > i_size_read(inode))
636 i_size_write(inode, i_size);
637 i_size = xfs_new_eof(ip, i_size);
638 if (i_size) {
639 ip->i_disk_size = i_size;
640 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
641 }
642
643 error = xfs_trans_commit(tp);
644 xfs_iunlock(ip, XFS_ILOCK_EXCL);
645 if (error)
646 return error;
647
648 if (unlikely(!xfs_valid_startblock(ip, imap.br_startblock))) {
649 xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
650 return xfs_alert_fsblock_zero(ip, &imap);
651 }
652
653 if ((numblks_fsb = imap.br_blockcount) == 0) {
654 /*
655 * The numblks_fsb value should always get
656 * smaller, otherwise the loop is stuck.
657 */
658 ASSERT(imap.br_blockcount);
659 break;
660 }
661 offset_fsb += numblks_fsb;
662 count_fsb -= numblks_fsb;
663 } while (count_fsb > 0);
664
665 return 0;
666
667error_on_bmapi_transaction:
668 xfs_trans_cancel(tp);
669 xfs_iunlock(ip, XFS_ILOCK_EXCL);
670 return error;
671}
672
673static inline bool
674imap_needs_alloc(
675 struct inode *inode,
676 unsigned flags,
677 struct xfs_bmbt_irec *imap,
678 int nimaps)
679{
680 /* don't allocate blocks when just zeroing */
681 if (flags & IOMAP_ZERO)
682 return false;
683 if (!nimaps ||
684 imap->br_startblock == HOLESTARTBLOCK ||
685 imap->br_startblock == DELAYSTARTBLOCK)
686 return true;
687 /* we convert unwritten extents before copying the data for DAX */
688 if ((flags & IOMAP_DAX) && imap->br_state == XFS_EXT_UNWRITTEN)
689 return true;
690 return false;
691}
692
693static inline bool
694imap_needs_cow(
695 struct xfs_inode *ip,
696 unsigned int flags,
697 struct xfs_bmbt_irec *imap,
698 int nimaps)
699{
700 if (!xfs_is_cow_inode(ip))
701 return false;
702
703 /* when zeroing we don't have to COW holes or unwritten extents */
704 if (flags & IOMAP_ZERO) {
705 if (!nimaps ||
706 imap->br_startblock == HOLESTARTBLOCK ||
707 imap->br_state == XFS_EXT_UNWRITTEN)
708 return false;
709 }
710
711 return true;
712}
713
714static int
715xfs_ilock_for_iomap(
716 struct xfs_inode *ip,
717 unsigned flags,
718 unsigned *lockmode)
719{
720 unsigned int mode = *lockmode;
721 bool is_write = flags & (IOMAP_WRITE | IOMAP_ZERO);
722
723 /*
724 * COW writes may allocate delalloc space or convert unwritten COW
725 * extents, so we need to make sure to take the lock exclusively here.
726 */
727 if (xfs_is_cow_inode(ip) && is_write)
728 mode = XFS_ILOCK_EXCL;
729
730 /*
731 * Extents not yet cached requires exclusive access, don't block. This
732 * is an opencoded xfs_ilock_data_map_shared() call but with
733 * non-blocking behaviour.
734 */
735 if (xfs_need_iread_extents(&ip->i_df)) {
736 if (flags & IOMAP_NOWAIT)
737 return -EAGAIN;
738 mode = XFS_ILOCK_EXCL;
739 }
740
741relock:
742 if (flags & IOMAP_NOWAIT) {
743 if (!xfs_ilock_nowait(ip, mode))
744 return -EAGAIN;
745 } else {
746 xfs_ilock(ip, mode);
747 }
748
749 /*
750 * The reflink iflag could have changed since the earlier unlocked
751 * check, so if we got ILOCK_SHARED for a write and but we're now a
752 * reflink inode we have to switch to ILOCK_EXCL and relock.
753 */
754 if (mode == XFS_ILOCK_SHARED && is_write && xfs_is_cow_inode(ip)) {
755 xfs_iunlock(ip, mode);
756 mode = XFS_ILOCK_EXCL;
757 goto relock;
758 }
759
760 *lockmode = mode;
761 return 0;
762}
763
764/*
765 * Check that the imap we are going to return to the caller spans the entire
766 * range that the caller requested for the IO.
767 */
768static bool
769imap_spans_range(
770 struct xfs_bmbt_irec *imap,
771 xfs_fileoff_t offset_fsb,
772 xfs_fileoff_t end_fsb)
773{
774 if (imap->br_startoff > offset_fsb)
775 return false;
776 if (imap->br_startoff + imap->br_blockcount < end_fsb)
777 return false;
778 return true;
779}
780
781static int
782xfs_direct_write_iomap_begin(
783 struct inode *inode,
784 loff_t offset,
785 loff_t length,
786 unsigned flags,
787 struct iomap *iomap,
788 struct iomap *srcmap)
789{
790 struct xfs_inode *ip = XFS_I(inode);
791 struct xfs_mount *mp = ip->i_mount;
792 struct xfs_bmbt_irec imap, cmap;
793 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
794 xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, length);
795 int nimaps = 1, error = 0;
796 bool shared = false;
797 u16 iomap_flags = 0;
798 unsigned int lockmode = XFS_ILOCK_SHARED;
799 u64 seq;
800
801 ASSERT(flags & (IOMAP_WRITE | IOMAP_ZERO));
802
803 if (xfs_is_shutdown(mp))
804 return -EIO;
805
806 /*
807 * Writes that span EOF might trigger an IO size update on completion,
808 * so consider them to be dirty for the purposes of O_DSYNC even if
809 * there is no other metadata changes pending or have been made here.
810 */
811 if (offset + length > i_size_read(inode))
812 iomap_flags |= IOMAP_F_DIRTY;
813
814 error = xfs_ilock_for_iomap(ip, flags, lockmode: &lockmode);
815 if (error)
816 return error;
817
818 error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
819 &nimaps, 0);
820 if (error)
821 goto out_unlock;
822
823 if (imap_needs_cow(ip, flags, imap: &imap, nimaps)) {
824 error = -EAGAIN;
825 if (flags & IOMAP_NOWAIT)
826 goto out_unlock;
827
828 /* may drop and re-acquire the ilock */
829 error = xfs_reflink_allocate_cow(ip, imap: &imap, cmap: &cmap, shared: &shared,
830 lockmode: &lockmode,
831 convert_now: (flags & IOMAP_DIRECT) || IS_DAX(inode));
832 if (error)
833 goto out_unlock;
834 if (shared)
835 goto out_found_cow;
836 end_fsb = imap.br_startoff + imap.br_blockcount;
837 length = XFS_FSB_TO_B(mp, end_fsb) - offset;
838 }
839
840 if (imap_needs_alloc(inode, flags, imap: &imap, nimaps))
841 goto allocate_blocks;
842
843 /*
844 * NOWAIT and OVERWRITE I/O needs to span the entire requested I/O with
845 * a single map so that we avoid partial IO failures due to the rest of
846 * the I/O range not covered by this map triggering an EAGAIN condition
847 * when it is subsequently mapped and aborting the I/O.
848 */
849 if (flags & (IOMAP_NOWAIT | IOMAP_OVERWRITE_ONLY)) {
850 error = -EAGAIN;
851 if (!imap_spans_range(&imap, offset_fsb, end_fsb))
852 goto out_unlock;
853 }
854
855 /*
856 * For overwrite only I/O, we cannot convert unwritten extents without
857 * requiring sub-block zeroing. This can only be done under an
858 * exclusive IOLOCK, hence return -EAGAIN if this is not a written
859 * extent to tell the caller to try again.
860 */
861 if (flags & IOMAP_OVERWRITE_ONLY) {
862 error = -EAGAIN;
863 if (imap.br_state != XFS_EXT_NORM &&
864 ((offset | length) & mp->m_blockmask))
865 goto out_unlock;
866 }
867
868 seq = xfs_iomap_inode_sequence(ip, iomap_flags);
869 xfs_iunlock(ip, lockmode);
870 trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
871 return xfs_bmbt_to_iomap(ip, iomap, imap: &imap, mapping_flags: flags, iomap_flags, sequence_cookie: seq);
872
873allocate_blocks:
874 error = -EAGAIN;
875 if (flags & (IOMAP_NOWAIT | IOMAP_OVERWRITE_ONLY))
876 goto out_unlock;
877
878 /*
879 * We cap the maximum length we map to a sane size to keep the chunks
880 * of work done where somewhat symmetric with the work writeback does.
881 * This is a completely arbitrary number pulled out of thin air as a
882 * best guess for initial testing.
883 *
884 * Note that the values needs to be less than 32-bits wide until the
885 * lower level functions are updated.
886 */
887 length = min_t(loff_t, length, 1024 * PAGE_SIZE);
888 end_fsb = xfs_iomap_end_fsb(mp, offset, length);
889
890 if (offset + length > XFS_ISIZE(ip))
891 end_fsb = xfs_iomap_eof_align_last_fsb(ip, end_fsb);
892 else if (nimaps && imap.br_startblock == HOLESTARTBLOCK)
893 end_fsb = min(end_fsb, imap.br_startoff + imap.br_blockcount);
894 xfs_iunlock(ip, lockmode);
895
896 error = xfs_iomap_write_direct(ip, offset_fsb, end_fsb - offset_fsb,
897 flags, &imap, &seq);
898 if (error)
899 return error;
900
901 trace_xfs_iomap_alloc(ip, offset, length, XFS_DATA_FORK, &imap);
902 return xfs_bmbt_to_iomap(ip, iomap, imap: &imap, mapping_flags: flags,
903 iomap_flags: iomap_flags | IOMAP_F_NEW, sequence_cookie: seq);
904
905out_found_cow:
906 length = XFS_FSB_TO_B(mp, cmap.br_startoff + cmap.br_blockcount);
907 trace_xfs_iomap_found(ip, offset, length - offset, XFS_COW_FORK, &cmap);
908 if (imap.br_startblock != HOLESTARTBLOCK) {
909 seq = xfs_iomap_inode_sequence(ip, iomap_flags: 0);
910 error = xfs_bmbt_to_iomap(ip, iomap: srcmap, imap: &imap, mapping_flags: flags, iomap_flags: 0, sequence_cookie: seq);
911 if (error)
912 goto out_unlock;
913 }
914 seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
915 xfs_iunlock(ip, lockmode);
916 return xfs_bmbt_to_iomap(ip, iomap, imap: &cmap, mapping_flags: flags, IOMAP_F_SHARED, sequence_cookie: seq);
917
918out_unlock:
919 if (lockmode)
920 xfs_iunlock(ip, lockmode);
921 return error;
922}
923
924const struct iomap_ops xfs_direct_write_iomap_ops = {
925 .iomap_begin = xfs_direct_write_iomap_begin,
926};
927
928static int
929xfs_dax_write_iomap_end(
930 struct inode *inode,
931 loff_t pos,
932 loff_t length,
933 ssize_t written,
934 unsigned flags,
935 struct iomap *iomap)
936{
937 struct xfs_inode *ip = XFS_I(inode);
938
939 if (!xfs_is_cow_inode(ip))
940 return 0;
941
942 if (!written) {
943 xfs_reflink_cancel_cow_range(ip, offset: pos, count: length, cancel_real: true);
944 return 0;
945 }
946
947 return xfs_reflink_end_cow(ip, offset: pos, count: written);
948}
949
950const struct iomap_ops xfs_dax_write_iomap_ops = {
951 .iomap_begin = xfs_direct_write_iomap_begin,
952 .iomap_end = xfs_dax_write_iomap_end,
953};
954
955static int
956xfs_buffered_write_iomap_begin(
957 struct inode *inode,
958 loff_t offset,
959 loff_t count,
960 unsigned flags,
961 struct iomap *iomap,
962 struct iomap *srcmap)
963{
964 struct xfs_inode *ip = XFS_I(inode);
965 struct xfs_mount *mp = ip->i_mount;
966 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
967 xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, count);
968 struct xfs_bmbt_irec imap, cmap;
969 struct xfs_iext_cursor icur, ccur;
970 xfs_fsblock_t prealloc_blocks = 0;
971 bool eof = false, cow_eof = false, shared = false;
972 int allocfork = XFS_DATA_FORK;
973 int error = 0;
974 unsigned int lockmode = XFS_ILOCK_EXCL;
975 u64 seq;
976
977 if (xfs_is_shutdown(mp))
978 return -EIO;
979
980 /* we can't use delayed allocations when using extent size hints */
981 if (xfs_get_extsz_hint(ip))
982 return xfs_direct_write_iomap_begin(inode, offset, length: count,
983 flags, iomap, srcmap);
984
985 ASSERT(!XFS_IS_REALTIME_INODE(ip));
986
987 error = xfs_qm_dqattach(ip);
988 if (error)
989 return error;
990
991 error = xfs_ilock_for_iomap(ip, flags, lockmode: &lockmode);
992 if (error)
993 return error;
994
995 if (XFS_IS_CORRUPT(mp, !xfs_ifork_has_extents(&ip->i_df)) ||
996 XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BMAPIFORMAT)) {
997 xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
998 error = -EFSCORRUPTED;
999 goto out_unlock;
1000 }
1001
1002 XFS_STATS_INC(mp, xs_blk_mapw);
1003
1004 error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
1005 if (error)
1006 goto out_unlock;
1007
1008 /*
1009 * Search the data fork first to look up our source mapping. We
1010 * always need the data fork map, as we have to return it to the
1011 * iomap code so that the higher level write code can read data in to
1012 * perform read-modify-write cycles for unaligned writes.
1013 */
1014 eof = !xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap);
1015 if (eof)
1016 imap.br_startoff = end_fsb; /* fake hole until the end */
1017
1018 /* We never need to allocate blocks for zeroing or unsharing a hole. */
1019 if ((flags & (IOMAP_UNSHARE | IOMAP_ZERO)) &&
1020 imap.br_startoff > offset_fsb) {
1021 xfs_hole_to_iomap(ip, iomap, offset_fsb, imap.br_startoff);
1022 goto out_unlock;
1023 }
1024
1025 /*
1026 * Search the COW fork extent list even if we did not find a data fork
1027 * extent. This serves two purposes: first this implements the
1028 * speculative preallocation using cowextsize, so that we also unshare
1029 * block adjacent to shared blocks instead of just the shared blocks
1030 * themselves. Second the lookup in the extent list is generally faster
1031 * than going out to the shared extent tree.
1032 */
1033 if (xfs_is_cow_inode(ip)) {
1034 if (!ip->i_cowfp) {
1035 ASSERT(!xfs_is_reflink_inode(ip));
1036 xfs_ifork_init_cow(ip);
1037 }
1038 cow_eof = !xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb,
1039 &ccur, &cmap);
1040 if (!cow_eof && cmap.br_startoff <= offset_fsb) {
1041 trace_xfs_reflink_cow_found(ip, irec: &cmap);
1042 goto found_cow;
1043 }
1044 }
1045
1046 if (imap.br_startoff <= offset_fsb) {
1047 /*
1048 * For reflink files we may need a delalloc reservation when
1049 * overwriting shared extents. This includes zeroing of
1050 * existing extents that contain data.
1051 */
1052 if (!xfs_is_cow_inode(ip) ||
1053 ((flags & IOMAP_ZERO) && imap.br_state != XFS_EXT_NORM)) {
1054 trace_xfs_iomap_found(ip, offset, count, XFS_DATA_FORK,
1055 &imap);
1056 goto found_imap;
1057 }
1058
1059 xfs_trim_extent(&imap, offset_fsb, end_fsb - offset_fsb);
1060
1061 /* Trim the mapping to the nearest shared extent boundary. */
1062 error = xfs_bmap_trim_cow(ip, imap: &imap, shared: &shared);
1063 if (error)
1064 goto out_unlock;
1065
1066 /* Not shared? Just report the (potentially capped) extent. */
1067 if (!shared) {
1068 trace_xfs_iomap_found(ip, offset, count, XFS_DATA_FORK,
1069 &imap);
1070 goto found_imap;
1071 }
1072
1073 /*
1074 * Fork all the shared blocks from our write offset until the
1075 * end of the extent.
1076 */
1077 allocfork = XFS_COW_FORK;
1078 end_fsb = imap.br_startoff + imap.br_blockcount;
1079 } else {
1080 /*
1081 * We cap the maximum length we map here to MAX_WRITEBACK_PAGES
1082 * pages to keep the chunks of work done where somewhat
1083 * symmetric with the work writeback does. This is a completely
1084 * arbitrary number pulled out of thin air.
1085 *
1086 * Note that the values needs to be less than 32-bits wide until
1087 * the lower level functions are updated.
1088 */
1089 count = min_t(loff_t, count, 1024 * PAGE_SIZE);
1090 end_fsb = xfs_iomap_end_fsb(mp, offset, count);
1091
1092 if (xfs_is_always_cow_inode(ip))
1093 allocfork = XFS_COW_FORK;
1094 }
1095
1096 if (eof && offset + count > XFS_ISIZE(ip)) {
1097 /*
1098 * Determine the initial size of the preallocation.
1099 * We clean up any extra preallocation when the file is closed.
1100 */
1101 if (xfs_has_allocsize(mp))
1102 prealloc_blocks = mp->m_allocsize_blocks;
1103 else if (allocfork == XFS_DATA_FORK)
1104 prealloc_blocks = xfs_iomap_prealloc_size(ip, allocfork,
1105 offset, count, &icur);
1106 else
1107 prealloc_blocks = xfs_iomap_prealloc_size(ip, allocfork,
1108 offset, count, &ccur);
1109 if (prealloc_blocks) {
1110 xfs_extlen_t align;
1111 xfs_off_t end_offset;
1112 xfs_fileoff_t p_end_fsb;
1113
1114 end_offset = XFS_ALLOC_ALIGN(mp, offset + count - 1);
1115 p_end_fsb = XFS_B_TO_FSBT(mp, end_offset) +
1116 prealloc_blocks;
1117
1118 align = xfs_eof_alignment(ip);
1119 if (align)
1120 p_end_fsb = roundup_64(p_end_fsb, align);
1121
1122 p_end_fsb = min(p_end_fsb,
1123 XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
1124 ASSERT(p_end_fsb > offset_fsb);
1125 prealloc_blocks = p_end_fsb - end_fsb;
1126 }
1127 }
1128
1129retry:
1130 error = xfs_bmapi_reserve_delalloc(ip, allocfork, offset_fsb,
1131 end_fsb - offset_fsb, prealloc_blocks,
1132 allocfork == XFS_DATA_FORK ? &imap : &cmap,
1133 allocfork == XFS_DATA_FORK ? &icur : &ccur,
1134 allocfork == XFS_DATA_FORK ? eof : cow_eof);
1135 switch (error) {
1136 case 0:
1137 break;
1138 case -ENOSPC:
1139 case -EDQUOT:
1140 /* retry without any preallocation */
1141 trace_xfs_delalloc_enospc(ip, offset, count);
1142 if (prealloc_blocks) {
1143 prealloc_blocks = 0;
1144 goto retry;
1145 }
1146 fallthrough;
1147 default:
1148 goto out_unlock;
1149 }
1150
1151 if (allocfork == XFS_COW_FORK) {
1152 trace_xfs_iomap_alloc(ip, offset, count, whichfork: allocfork, irec: &cmap);
1153 goto found_cow;
1154 }
1155
1156 /*
1157 * Flag newly allocated delalloc blocks with IOMAP_F_NEW so we punch
1158 * them out if the write happens to fail.
1159 */
1160 seq = xfs_iomap_inode_sequence(ip, IOMAP_F_NEW);
1161 xfs_iunlock(ip, XFS_ILOCK_EXCL);
1162 trace_xfs_iomap_alloc(ip, offset, count, whichfork: allocfork, irec: &imap);
1163 return xfs_bmbt_to_iomap(ip, iomap, imap: &imap, mapping_flags: flags, IOMAP_F_NEW, sequence_cookie: seq);
1164
1165found_imap:
1166 seq = xfs_iomap_inode_sequence(ip, iomap_flags: 0);
1167 xfs_iunlock(ip, XFS_ILOCK_EXCL);
1168 return xfs_bmbt_to_iomap(ip, iomap, imap: &imap, mapping_flags: flags, iomap_flags: 0, sequence_cookie: seq);
1169
1170found_cow:
1171 seq = xfs_iomap_inode_sequence(ip, iomap_flags: 0);
1172 if (imap.br_startoff <= offset_fsb) {
1173 error = xfs_bmbt_to_iomap(ip, iomap: srcmap, imap: &imap, mapping_flags: flags, iomap_flags: 0, sequence_cookie: seq);
1174 if (error)
1175 goto out_unlock;
1176 seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
1177 xfs_iunlock(ip, XFS_ILOCK_EXCL);
1178 return xfs_bmbt_to_iomap(ip, iomap, imap: &cmap, mapping_flags: flags,
1179 IOMAP_F_SHARED, sequence_cookie: seq);
1180 }
1181
1182 xfs_trim_extent(&cmap, offset_fsb, imap.br_startoff - offset_fsb);
1183 xfs_iunlock(ip, XFS_ILOCK_EXCL);
1184 return xfs_bmbt_to_iomap(ip, iomap, imap: &cmap, mapping_flags: flags, iomap_flags: 0, sequence_cookie: seq);
1185
1186out_unlock:
1187 xfs_iunlock(ip, XFS_ILOCK_EXCL);
1188 return error;
1189}
1190
1191static int
1192xfs_buffered_write_delalloc_punch(
1193 struct inode *inode,
1194 loff_t offset,
1195 loff_t length)
1196{
1197 return xfs_bmap_punch_delalloc_range(ip: XFS_I(inode), start_byte: offset,
1198 end_byte: offset + length);
1199}
1200
1201static int
1202xfs_buffered_write_iomap_end(
1203 struct inode *inode,
1204 loff_t offset,
1205 loff_t length,
1206 ssize_t written,
1207 unsigned flags,
1208 struct iomap *iomap)
1209{
1210
1211 struct xfs_mount *mp = XFS_M(inode->i_sb);
1212 int error;
1213
1214 error = iomap_file_buffered_write_punch_delalloc(inode, iomap, pos: offset,
1215 length, written, punch: &xfs_buffered_write_delalloc_punch);
1216 if (error && !xfs_is_shutdown(mp)) {
1217 xfs_alert(mp, "%s: unable to clean up ino 0x%llx",
1218 __func__, XFS_I(inode)->i_ino);
1219 return error;
1220 }
1221 return 0;
1222}
1223
1224const struct iomap_ops xfs_buffered_write_iomap_ops = {
1225 .iomap_begin = xfs_buffered_write_iomap_begin,
1226 .iomap_end = xfs_buffered_write_iomap_end,
1227};
1228
1229/*
1230 * iomap_page_mkwrite() will never fail in a way that requires delalloc extents
1231 * that it allocated to be revoked. Hence we do not need an .iomap_end method
1232 * for this operation.
1233 */
1234const struct iomap_ops xfs_page_mkwrite_iomap_ops = {
1235 .iomap_begin = xfs_buffered_write_iomap_begin,
1236};
1237
1238static int
1239xfs_read_iomap_begin(
1240 struct inode *inode,
1241 loff_t offset,
1242 loff_t length,
1243 unsigned flags,
1244 struct iomap *iomap,
1245 struct iomap *srcmap)
1246{
1247 struct xfs_inode *ip = XFS_I(inode);
1248 struct xfs_mount *mp = ip->i_mount;
1249 struct xfs_bmbt_irec imap;
1250 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
1251 xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, length);
1252 int nimaps = 1, error = 0;
1253 bool shared = false;
1254 unsigned int lockmode = XFS_ILOCK_SHARED;
1255 u64 seq;
1256
1257 ASSERT(!(flags & (IOMAP_WRITE | IOMAP_ZERO)));
1258
1259 if (xfs_is_shutdown(mp))
1260 return -EIO;
1261
1262 error = xfs_ilock_for_iomap(ip, flags, lockmode: &lockmode);
1263 if (error)
1264 return error;
1265 error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
1266 &nimaps, 0);
1267 if (!error && ((flags & IOMAP_REPORT) || IS_DAX(inode)))
1268 error = xfs_reflink_trim_around_shared(ip, irec: &imap, shared: &shared);
1269 seq = xfs_iomap_inode_sequence(ip, iomap_flags: shared ? IOMAP_F_SHARED : 0);
1270 xfs_iunlock(ip, lockmode);
1271
1272 if (error)
1273 return error;
1274 trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
1275 return xfs_bmbt_to_iomap(ip, iomap, imap: &imap, mapping_flags: flags,
1276 iomap_flags: shared ? IOMAP_F_SHARED : 0, sequence_cookie: seq);
1277}
1278
1279const struct iomap_ops xfs_read_iomap_ops = {
1280 .iomap_begin = xfs_read_iomap_begin,
1281};
1282
1283static int
1284xfs_seek_iomap_begin(
1285 struct inode *inode,
1286 loff_t offset,
1287 loff_t length,
1288 unsigned flags,
1289 struct iomap *iomap,
1290 struct iomap *srcmap)
1291{
1292 struct xfs_inode *ip = XFS_I(inode);
1293 struct xfs_mount *mp = ip->i_mount;
1294 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
1295 xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + length);
1296 xfs_fileoff_t cow_fsb = NULLFILEOFF, data_fsb = NULLFILEOFF;
1297 struct xfs_iext_cursor icur;
1298 struct xfs_bmbt_irec imap, cmap;
1299 int error = 0;
1300 unsigned lockmode;
1301 u64 seq;
1302
1303 if (xfs_is_shutdown(mp))
1304 return -EIO;
1305
1306 lockmode = xfs_ilock_data_map_shared(ip);
1307 error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
1308 if (error)
1309 goto out_unlock;
1310
1311 if (xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap)) {
1312 /*
1313 * If we found a data extent we are done.
1314 */
1315 if (imap.br_startoff <= offset_fsb)
1316 goto done;
1317 data_fsb = imap.br_startoff;
1318 } else {
1319 /*
1320 * Fake a hole until the end of the file.
1321 */
1322 data_fsb = xfs_iomap_end_fsb(mp, offset, length);
1323 }
1324
1325 /*
1326 * If a COW fork extent covers the hole, report it - capped to the next
1327 * data fork extent:
1328 */
1329 if (xfs_inode_has_cow_data(ip) &&
1330 xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &cmap))
1331 cow_fsb = cmap.br_startoff;
1332 if (cow_fsb != NULLFILEOFF && cow_fsb <= offset_fsb) {
1333 if (data_fsb < cow_fsb + cmap.br_blockcount)
1334 end_fsb = min(end_fsb, data_fsb);
1335 xfs_trim_extent(&cmap, offset_fsb, end_fsb - offset_fsb);
1336 seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
1337 error = xfs_bmbt_to_iomap(ip, iomap, imap: &cmap, mapping_flags: flags,
1338 IOMAP_F_SHARED, sequence_cookie: seq);
1339 /*
1340 * This is a COW extent, so we must probe the page cache
1341 * because there could be dirty page cache being backed
1342 * by this extent.
1343 */
1344 iomap->type = IOMAP_UNWRITTEN;
1345 goto out_unlock;
1346 }
1347
1348 /*
1349 * Else report a hole, capped to the next found data or COW extent.
1350 */
1351 if (cow_fsb != NULLFILEOFF && cow_fsb < data_fsb)
1352 imap.br_blockcount = cow_fsb - offset_fsb;
1353 else
1354 imap.br_blockcount = data_fsb - offset_fsb;
1355 imap.br_startoff = offset_fsb;
1356 imap.br_startblock = HOLESTARTBLOCK;
1357 imap.br_state = XFS_EXT_NORM;
1358done:
1359 seq = xfs_iomap_inode_sequence(ip, iomap_flags: 0);
1360 xfs_trim_extent(&imap, offset_fsb, end_fsb - offset_fsb);
1361 error = xfs_bmbt_to_iomap(ip, iomap, imap: &imap, mapping_flags: flags, iomap_flags: 0, sequence_cookie: seq);
1362out_unlock:
1363 xfs_iunlock(ip, lockmode);
1364 return error;
1365}
1366
1367const struct iomap_ops xfs_seek_iomap_ops = {
1368 .iomap_begin = xfs_seek_iomap_begin,
1369};
1370
1371static int
1372xfs_xattr_iomap_begin(
1373 struct inode *inode,
1374 loff_t offset,
1375 loff_t length,
1376 unsigned flags,
1377 struct iomap *iomap,
1378 struct iomap *srcmap)
1379{
1380 struct xfs_inode *ip = XFS_I(inode);
1381 struct xfs_mount *mp = ip->i_mount;
1382 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
1383 xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + length);
1384 struct xfs_bmbt_irec imap;
1385 int nimaps = 1, error = 0;
1386 unsigned lockmode;
1387 int seq;
1388
1389 if (xfs_is_shutdown(mp))
1390 return -EIO;
1391
1392 lockmode = xfs_ilock_attr_map_shared(ip);
1393
1394 /* if there are no attribute fork or extents, return ENOENT */
1395 if (!xfs_inode_has_attr_fork(ip) || !ip->i_af.if_nextents) {
1396 error = -ENOENT;
1397 goto out_unlock;
1398 }
1399
1400 ASSERT(ip->i_af.if_format != XFS_DINODE_FMT_LOCAL);
1401 error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
1402 &nimaps, XFS_BMAPI_ATTRFORK);
1403out_unlock:
1404
1405 seq = xfs_iomap_inode_sequence(ip, IOMAP_F_XATTR);
1406 xfs_iunlock(ip, lockmode);
1407
1408 if (error)
1409 return error;
1410 ASSERT(nimaps);
1411 return xfs_bmbt_to_iomap(ip, iomap, imap: &imap, mapping_flags: flags, IOMAP_F_XATTR, sequence_cookie: seq);
1412}
1413
1414const struct iomap_ops xfs_xattr_iomap_ops = {
1415 .iomap_begin = xfs_xattr_iomap_begin,
1416};
1417
1418int
1419xfs_zero_range(
1420 struct xfs_inode *ip,
1421 loff_t pos,
1422 loff_t len,
1423 bool *did_zero)
1424{
1425 struct inode *inode = VFS_I(ip);
1426
1427 if (IS_DAX(inode))
1428 return dax_zero_range(inode, pos, len, did_zero,
1429 ops: &xfs_dax_write_iomap_ops);
1430 return iomap_zero_range(inode, pos, len, did_zero,
1431 ops: &xfs_buffered_write_iomap_ops);
1432}
1433
1434int
1435xfs_truncate_page(
1436 struct xfs_inode *ip,
1437 loff_t pos,
1438 bool *did_zero)
1439{
1440 struct inode *inode = VFS_I(ip);
1441
1442 if (IS_DAX(inode))
1443 return dax_truncate_page(inode, pos, did_zero,
1444 ops: &xfs_dax_write_iomap_ops);
1445 return iomap_truncate_page(inode, pos, did_zero,
1446 ops: &xfs_buffered_write_iomap_ops);
1447}
1448

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