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 #include "xfs_rtbitmap.h"
32
33 #define XFS_ALLOC_ALIGN(mp, off) \
34 (((off) >> mp->m_allocsize_log) << mp->m_allocsize_log)
35
36 static int
37 xfs_alert_fsblock_zero(
38 xfs_inode_t *ip,
39 xfs_bmbt_irec_t *imap)
40 {
41 xfs_alert_tag(ip->i_mount, XFS_PTAG_FSBLOCK_ZERO,
42 "Access to block zero in inode %llu "
43 "start_block: %llx start_off: %llx "
44 "blkcnt: %llx extent-state: %x",
45 (unsigned long long)ip->i_ino,
46 (unsigned long long)imap->br_startblock,
47 (unsigned long long)imap->br_startoff,
48 (unsigned long long)imap->br_blockcount,
49 imap->br_state);
50 xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
51 return -EFSCORRUPTED;
52 }
53
54 u64
55 xfs_iomap_inode_sequence(
56 struct xfs_inode *ip,
57 u16 iomap_flags)
58 {
59 u64 cookie = 0;
60
61 if (iomap_flags & IOMAP_F_XATTR)
62 return READ_ONCE(ip->i_af.if_seq);
63 if ((iomap_flags & IOMAP_F_SHARED) && ip->i_cowfp)
64 cookie = (u64)READ_ONCE(ip->i_cowfp->if_seq) << 32;
65 return cookie | READ_ONCE(ip->i_df.if_seq);
66 }
67
68 /*
69 * Check that the iomap passed to us is still valid for the given offset and
70 * length.
71 */
72 static bool
73 xfs_iomap_valid(
74 struct inode *inode,
75 const struct iomap *iomap)
76 {
77 struct xfs_inode *ip = XFS_I(inode);
78
79 if (iomap->validity_cookie !=
80 xfs_iomap_inode_sequence(ip, iomap->flags)) {
81 trace_xfs_iomap_invalid(ip, iomap);
82 return false;
83 }
84
85 XFS_ERRORTAG_DELAY(ip->i_mount, XFS_ERRTAG_WRITE_DELAY_MS);
86 return true;
87 }
88
89 static const struct iomap_folio_ops xfs_iomap_folio_ops = {
90 .iomap_valid = xfs_iomap_valid,
91 };
92
93 int
94 xfs_bmbt_to_iomap(
95 struct xfs_inode *ip,
96 struct iomap *iomap,
97 struct xfs_bmbt_irec *imap,
98 unsigned int mapping_flags,
99 u16 iomap_flags,
100 u64 sequence_cookie)
101 {
102 struct xfs_mount *mp = ip->i_mount;
103 struct xfs_buftarg *target = xfs_inode_buftarg(ip);
104
105 if (unlikely(!xfs_valid_startblock(ip, imap->br_startblock))) {
106 xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
107 return xfs_alert_fsblock_zero(ip, imap);
108 }
109
110 if (imap->br_startblock == HOLESTARTBLOCK) {
111 iomap->addr = IOMAP_NULL_ADDR;
112 iomap->type = IOMAP_HOLE;
113 } else if (imap->br_startblock == DELAYSTARTBLOCK ||
114 isnullstartblock(imap->br_startblock)) {
115 iomap->addr = IOMAP_NULL_ADDR;
116 iomap->type = IOMAP_DELALLOC;
117 } else {
118 iomap->addr = BBTOB(xfs_fsb_to_db(ip, imap->br_startblock));
119 if (mapping_flags & IOMAP_DAX)
120 iomap->addr += target->bt_dax_part_off;
121
122 if (imap->br_state == XFS_EXT_UNWRITTEN)
123 iomap->type = IOMAP_UNWRITTEN;
124 else
125 iomap->type = IOMAP_MAPPED;
126
127 }
128 iomap->offset = XFS_FSB_TO_B(mp, imap->br_startoff);
129 iomap->length = XFS_FSB_TO_B(mp, imap->br_blockcount);
130 if (mapping_flags & IOMAP_DAX)
131 iomap->dax_dev = target->bt_daxdev;
132 else
133 iomap->bdev = target->bt_bdev;
134 iomap->flags = iomap_flags;
135
136 if (xfs_ipincount(ip) &&
137 (ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
138 iomap->flags |= IOMAP_F_DIRTY;
139
140 iomap->validity_cookie = sequence_cookie;
141 iomap->folio_ops = &xfs_iomap_folio_ops;
142 return 0;
143 }
144
145 static void
146 xfs_hole_to_iomap(
147 struct xfs_inode *ip,
148 struct iomap *iomap,
149 xfs_fileoff_t offset_fsb,
150 xfs_fileoff_t end_fsb)
151 {
152 struct xfs_buftarg *target = xfs_inode_buftarg(ip);
153
154 iomap->addr = IOMAP_NULL_ADDR;
155 iomap->type = IOMAP_HOLE;
156 iomap->offset = XFS_FSB_TO_B(ip->i_mount, offset_fsb);
157 iomap->length = XFS_FSB_TO_B(ip->i_mount, end_fsb - offset_fsb);
158 iomap->bdev = target->bt_bdev;
159 iomap->dax_dev = target->bt_daxdev;
160 }
161
162 static inline xfs_fileoff_t
163 xfs_iomap_end_fsb(
164 struct xfs_mount *mp,
165 loff_t offset,
166 loff_t count)
167 {
168 ASSERT(offset <= mp->m_super->s_maxbytes);
169 return min(XFS_B_TO_FSB(mp, offset + count),
170 XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
171 }
172
173 static xfs_extlen_t
174 xfs_eof_alignment(
175 struct xfs_inode *ip)
176 {
177 struct xfs_mount *mp = ip->i_mount;
178 xfs_extlen_t align = 0;
179
180 if (!XFS_IS_REALTIME_INODE(ip)) {
181 /*
182 * Round up the allocation request to a stripe unit
183 * (m_dalign) boundary if the file size is >= stripe unit
184 * size, and we are allocating past the allocation eof.
185 *
186 * If mounted with the "-o swalloc" option the alignment is
187 * increased from the strip unit size to the stripe width.
188 */
189 if (mp->m_swidth && xfs_has_swalloc(mp))
190 align = mp->m_swidth;
191 else if (mp->m_dalign)
192 align = mp->m_dalign;
193
194 if (align && XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, align))
195 align = 0;
196 }
197
198 return align;
199 }
200
201 /*
202 * Check if last_fsb is outside the last extent, and if so grow it to the next
203 * stripe unit boundary.
204 */
205 xfs_fileoff_t
206 xfs_iomap_eof_align_last_fsb(
207 struct xfs_inode *ip,
208 xfs_fileoff_t end_fsb)
209 {
210 struct xfs_ifork *ifp = xfs_ifork_ptr(ip, XFS_DATA_FORK);
211 xfs_extlen_t extsz = xfs_get_extsz_hint(ip);
212 xfs_extlen_t align = xfs_eof_alignment(ip);
213 struct xfs_bmbt_irec irec;
214 struct xfs_iext_cursor icur;
215
216 ASSERT(!xfs_need_iread_extents(ifp));
217
218 /*
219 * Always round up the allocation request to the extent hint boundary.
220 */
221 if (extsz) {
222 if (align)
223 align = roundup_64(align, extsz);
224 else
225 align = extsz;
226 }
227
228 if (align) {
229 xfs_fileoff_t aligned_end_fsb = roundup_64(end_fsb, align);
230
231 xfs_iext_last(ifp, &icur);
232 if (!xfs_iext_get_extent(ifp, &icur, &irec) ||
233 aligned_end_fsb >= irec.br_startoff + irec.br_blockcount)
234 return aligned_end_fsb;
235 }
236
237 return end_fsb;
238 }
239
240 int
241 xfs_iomap_write_direct(
242 struct xfs_inode *ip,
243 xfs_fileoff_t offset_fsb,
244 xfs_fileoff_t count_fsb,
245 unsigned int flags,
246 struct xfs_bmbt_irec *imap,
247 u64 *seq)
248 {
249 struct xfs_mount *mp = ip->i_mount;
250 struct xfs_trans *tp;
251 xfs_filblks_t resaligned;
252 int nimaps;
253 unsigned int dblocks, rblocks;
254 bool force = false;
255 int error;
256 int bmapi_flags = XFS_BMAPI_PREALLOC;
257 int nr_exts = XFS_IEXT_ADD_NOSPLIT_CNT;
258
259 ASSERT(count_fsb > 0);
260
261 resaligned = xfs_aligned_fsb_count(offset_fsb, count_fsb,
262 xfs_get_extsz_hint(ip));
263 if (unlikely(XFS_IS_REALTIME_INODE(ip))) {
264 dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
265 rblocks = resaligned;
266 } else {
267 dblocks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
268 rblocks = 0;
269 }
270
271 error = xfs_qm_dqattach(ip);
272 if (error)
273 return error;
274
275 /*
276 * For DAX, we do not allocate unwritten extents, but instead we zero
277 * the block before we commit the transaction. Ideally we'd like to do
278 * this outside the transaction context, but if we commit and then crash
279 * we may not have zeroed the blocks and this will be exposed on
280 * recovery of the allocation. Hence we must zero before commit.
281 *
282 * Further, if we are mapping unwritten extents here, we need to zero
283 * and convert them to written so that we don't need an unwritten extent
284 * callback for DAX. This also means that we need to be able to dip into
285 * the reserve block pool for bmbt block allocation if there is no space
286 * left but we need to do unwritten extent conversion.
287 */
288 if (flags & IOMAP_DAX) {
289 bmapi_flags = XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO;
290 if (imap->br_state == XFS_EXT_UNWRITTEN) {
291 force = true;
292 nr_exts = XFS_IEXT_WRITE_UNWRITTEN_CNT;
293 dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
294 }
295 }
296
297 error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, dblocks,
298 rblocks, force, &tp);
299 if (error)
300 return error;
301
302 error = xfs_iext_count_extend(tp, ip, XFS_DATA_FORK, nr_exts);
303 if (error)
304 goto out_trans_cancel;
305
306 /*
307 * From this point onwards we overwrite the imap pointer that the
308 * caller gave to us.
309 */
310 nimaps = 1;
311 error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb, bmapi_flags, 0,
312 imap, &nimaps);
313 if (error)
314 goto out_trans_cancel;
315
316 /*
317 * Complete the transaction
318 */
319 error = xfs_trans_commit(tp);
320 if (error)
321 goto out_unlock;
322
323 if (unlikely(!xfs_valid_startblock(ip, imap->br_startblock))) {
324 xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
325 error = xfs_alert_fsblock_zero(ip, imap);
326 }
327
328 out_unlock:
329 *seq = xfs_iomap_inode_sequence(ip, 0);
330 xfs_iunlock(ip, XFS_ILOCK_EXCL);
331 return error;
332
333 out_trans_cancel:
334 xfs_trans_cancel(tp);
335 goto out_unlock;
336 }
337
338 STATIC bool
339 xfs_quota_need_throttle(
340 struct xfs_inode *ip,
341 xfs_dqtype_t type,
342 xfs_fsblock_t alloc_blocks)
343 {
344 struct xfs_dquot *dq = xfs_inode_dquot(ip, type);
345
346 if (!dq || !xfs_this_quota_on(ip->i_mount, type))
347 return false;
348
349 /* no hi watermark, no throttle */
350 if (!dq->q_prealloc_hi_wmark)
351 return false;
352
353 /* under the lo watermark, no throttle */
354 if (dq->q_blk.reserved + alloc_blocks < dq->q_prealloc_lo_wmark)
355 return false;
356
357 return true;
358 }
359
360 STATIC void
361 xfs_quota_calc_throttle(
362 struct xfs_inode *ip,
363 xfs_dqtype_t type,
364 xfs_fsblock_t *qblocks,
365 int *qshift,
366 int64_t *qfreesp)
367 {
368 struct xfs_dquot *dq = xfs_inode_dquot(ip, type);
369 int64_t freesp;
370 int shift = 0;
371
372 /* no dq, or over hi wmark, squash the prealloc completely */
373 if (!dq || dq->q_blk.reserved >= dq->q_prealloc_hi_wmark) {
374 *qblocks = 0;
375 *qfreesp = 0;
376 return;
377 }
378
379 freesp = dq->q_prealloc_hi_wmark - dq->q_blk.reserved;
380 if (freesp < dq->q_low_space[XFS_QLOWSP_5_PCNT]) {
381 shift = 2;
382 if (freesp < dq->q_low_space[XFS_QLOWSP_3_PCNT])
383 shift += 2;
384 if (freesp < dq->q_low_space[XFS_QLOWSP_1_PCNT])
385 shift += 2;
386 }
387
388 if (freesp < *qfreesp)
389 *qfreesp = freesp;
390
391 /* only overwrite the throttle values if we are more aggressive */
392 if ((freesp >> shift) < (*qblocks >> *qshift)) {
393 *qblocks = freesp;
394 *qshift = shift;
395 }
396 }
397
398 static int64_t
399 xfs_iomap_freesp(
400 struct percpu_counter *counter,
401 uint64_t low_space[XFS_LOWSP_MAX],
402 int *shift)
403 {
404 int64_t freesp;
405
406 freesp = percpu_counter_read_positive(counter);
407 if (freesp < low_space[XFS_LOWSP_5_PCNT]) {
408 *shift = 2;
409 if (freesp < low_space[XFS_LOWSP_4_PCNT])
410 (*shift)++;
411 if (freesp < low_space[XFS_LOWSP_3_PCNT])
412 (*shift)++;
413 if (freesp < low_space[XFS_LOWSP_2_PCNT])
414 (*shift)++;
415 if (freesp < low_space[XFS_LOWSP_1_PCNT])
416 (*shift)++;
417 }
418 return freesp;
419 }
420
421 /*
422 * If we don't have a user specified preallocation size, dynamically increase
423 * the preallocation size as the size of the file grows. Cap the maximum size
424 * at a single extent or less if the filesystem is near full. The closer the
425 * filesystem is to being full, the smaller the maximum preallocation.
426 */
427 STATIC xfs_fsblock_t
428 xfs_iomap_prealloc_size(
429 struct xfs_inode *ip,
430 int whichfork,
431 loff_t offset,
432 loff_t count,
433 struct xfs_iext_cursor *icur)
434 {
435 struct xfs_iext_cursor ncur = *icur;
436 struct xfs_bmbt_irec prev, got;
437 struct xfs_mount *mp = ip->i_mount;
438 struct xfs_ifork *ifp = xfs_ifork_ptr(ip, whichfork);
439 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
440 int64_t freesp;
441 xfs_fsblock_t qblocks;
442 xfs_fsblock_t alloc_blocks = 0;
443 xfs_extlen_t plen;
444 int shift = 0;
445 int qshift = 0;
446
447 /*
448 * As an exception we don't do any preallocation at all if the file is
449 * smaller than the minimum preallocation and we are using the default
450 * dynamic preallocation scheme, as it is likely this is the only write
451 * to the file that is going to be done.
452 */
453 if (XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_allocsize_blocks))
454 return 0;
455
456 /*
457 * Use the minimum preallocation size for small files or if we are
458 * writing right after a hole.
459 */
460 if (XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_dalign) ||
461 !xfs_iext_prev_extent(ifp, &ncur, &prev) ||
462 prev.br_startoff + prev.br_blockcount < offset_fsb)
463 return mp->m_allocsize_blocks;
464
465 /*
466 * Take the size of the preceding data extents as the basis for the
467 * preallocation size. Note that we don't care if the previous extents
468 * are written or not.
469 */
470 plen = prev.br_blockcount;
471 while (xfs_iext_prev_extent(ifp, &ncur, &got)) {
472 if (plen > XFS_MAX_BMBT_EXTLEN / 2 ||
473 isnullstartblock(got.br_startblock) ||
474 got.br_startoff + got.br_blockcount != prev.br_startoff ||
475 got.br_startblock + got.br_blockcount != prev.br_startblock)
476 break;
477 plen += got.br_blockcount;
478 prev = got;
479 }
480
481 /*
482 * If the size of the extents is greater than half the maximum extent
483 * length, then use the current offset as the basis. This ensures that
484 * for large files the preallocation size always extends to
485 * XFS_BMBT_MAX_EXTLEN rather than falling short due to things like stripe
486 * unit/width alignment of real extents.
487 */
488 alloc_blocks = plen * 2;
489 if (alloc_blocks > XFS_MAX_BMBT_EXTLEN)
490 alloc_blocks = XFS_B_TO_FSB(mp, offset);
491 qblocks = alloc_blocks;
492
493 /*
494 * XFS_BMBT_MAX_EXTLEN is not a power of two value but we round the prealloc
495 * down to the nearest power of two value after throttling. To prevent
496 * the round down from unconditionally reducing the maximum supported
497 * prealloc size, we round up first, apply appropriate throttling, round
498 * down and cap the value to XFS_BMBT_MAX_EXTLEN.
499 */
500 alloc_blocks = XFS_FILEOFF_MIN(roundup_pow_of_two(XFS_MAX_BMBT_EXTLEN),
501 alloc_blocks);
502
503 if (unlikely(XFS_IS_REALTIME_INODE(ip)))
504 freesp = xfs_rtx_to_rtb(mp,
505 xfs_iomap_freesp(&mp->m_frextents,
506 mp->m_low_rtexts, &shift));
507 else
508 freesp = xfs_iomap_freesp(&mp->m_fdblocks, mp->m_low_space,
509 &shift);
510
511 /*
512 * Check each quota to cap the prealloc size, provide a shift value to
513 * throttle with and adjust amount of available space.
514 */
515 if (xfs_quota_need_throttle(ip, XFS_DQTYPE_USER, alloc_blocks))
516 xfs_quota_calc_throttle(ip, XFS_DQTYPE_USER, &qblocks, &qshift,
517 &freesp);
518 if (xfs_quota_need_throttle(ip, XFS_DQTYPE_GROUP, alloc_blocks))
519 xfs_quota_calc_throttle(ip, XFS_DQTYPE_GROUP, &qblocks, &qshift,
520 &freesp);
521 if (xfs_quota_need_throttle(ip, XFS_DQTYPE_PROJ, alloc_blocks))
522 xfs_quota_calc_throttle(ip, XFS_DQTYPE_PROJ, &qblocks, &qshift,
523 &freesp);
524
525 /*
526 * The final prealloc size is set to the minimum of free space available
527 * in each of the quotas and the overall filesystem.
528 *
529 * The shift throttle value is set to the maximum value as determined by
530 * the global low free space values and per-quota low free space values.
531 */
532 alloc_blocks = min(alloc_blocks, qblocks);
533 shift = max(shift, qshift);
534
535 if (shift)
536 alloc_blocks >>= shift;
537 /*
538 * rounddown_pow_of_two() returns an undefined result if we pass in
539 * alloc_blocks = 0.
540 */
541 if (alloc_blocks)
542 alloc_blocks = rounddown_pow_of_two(alloc_blocks);
543 if (alloc_blocks > XFS_MAX_BMBT_EXTLEN)
544 alloc_blocks = XFS_MAX_BMBT_EXTLEN;
545
546 /*
547 * If we are still trying to allocate more space than is
548 * available, squash the prealloc hard. This can happen if we
549 * have a large file on a small filesystem and the above
550 * lowspace thresholds are smaller than XFS_BMBT_MAX_EXTLEN.
551 */
552 while (alloc_blocks && alloc_blocks >= freesp)
553 alloc_blocks >>= 4;
554 if (alloc_blocks < mp->m_allocsize_blocks)
555 alloc_blocks = mp->m_allocsize_blocks;
556 trace_xfs_iomap_prealloc_size(ip, alloc_blocks, shift,
557 mp->m_allocsize_blocks);
558 return alloc_blocks;
559 }
560
561 int
562 xfs_iomap_write_unwritten(
563 xfs_inode_t *ip,
564 xfs_off_t offset,
565 xfs_off_t count,
566 bool update_isize)
567 {
568 xfs_mount_t *mp = ip->i_mount;
569 xfs_fileoff_t offset_fsb;
570 xfs_filblks_t count_fsb;
571 xfs_filblks_t numblks_fsb;
572 int nimaps;
573 xfs_trans_t *tp;
574 xfs_bmbt_irec_t imap;
575 struct inode *inode = VFS_I(ip);
576 xfs_fsize_t i_size;
577 uint resblks;
578 int error;
579
580 trace_xfs_unwritten_convert(ip, offset, count);
581
582 offset_fsb = XFS_B_TO_FSBT(mp, offset);
583 count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
584 count_fsb = (xfs_filblks_t)(count_fsb - offset_fsb);
585
586 /*
587 * Reserve enough blocks in this transaction for two complete extent
588 * btree splits. We may be converting the middle part of an unwritten
589 * extent and in this case we will insert two new extents in the btree
590 * each of which could cause a full split.
591 *
592 * This reservation amount will be used in the first call to
593 * xfs_bmbt_split() to select an AG with enough space to satisfy the
594 * rest of the operation.
595 */
596 resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
597
598 /* Attach dquots so that bmbt splits are accounted correctly. */
599 error = xfs_qm_dqattach(ip);
600 if (error)
601 return error;
602
603 do {
604 /*
605 * Set up a transaction to convert the range of extents
606 * from unwritten to real. Do allocations in a loop until
607 * we have covered the range passed in.
608 *
609 * Note that we can't risk to recursing back into the filesystem
610 * here as we might be asked to write out the same inode that we
611 * complete here and might deadlock on the iolock.
612 */
613 error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, resblks,
614 0, true, &tp);
615 if (error)
616 return error;
617
618 error = xfs_iext_count_extend(tp, ip, XFS_DATA_FORK,
619 XFS_IEXT_WRITE_UNWRITTEN_CNT);
620 if (error)
621 goto error_on_bmapi_transaction;
622
623 /*
624 * Modify the unwritten extent state of the buffer.
625 */
626 nimaps = 1;
627 error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb,
628 XFS_BMAPI_CONVERT, resblks, &imap,
629 &nimaps);
630 if (error)
631 goto error_on_bmapi_transaction;
632
633 /*
634 * Log the updated inode size as we go. We have to be careful
635 * to only log it up to the actual write offset if it is
636 * halfway into a block.
637 */
638 i_size = XFS_FSB_TO_B(mp, offset_fsb + count_fsb);
639 if (i_size > offset + count)
640 i_size = offset + count;
641 if (update_isize && i_size > i_size_read(inode))
642 i_size_write(inode, i_size);
643 i_size = xfs_new_eof(ip, i_size);
644 if (i_size) {
645 ip->i_disk_size = i_size;
646 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
647 }
648
649 error = xfs_trans_commit(tp);
650 xfs_iunlock(ip, XFS_ILOCK_EXCL);
651 if (error)
652 return error;
653
654 if (unlikely(!xfs_valid_startblock(ip, imap.br_startblock))) {
655 xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
656 return xfs_alert_fsblock_zero(ip, &imap);
657 }
658
659 if ((numblks_fsb = imap.br_blockcount) == 0) {
660 /*
661 * The numblks_fsb value should always get
662 * smaller, otherwise the loop is stuck.
663 */
664 ASSERT(imap.br_blockcount);
665 break;
666 }
667 offset_fsb += numblks_fsb;
668 count_fsb -= numblks_fsb;
669 } while (count_fsb > 0);
670
671 return 0;
672
673 error_on_bmapi_transaction:
674 xfs_trans_cancel(tp);
675 xfs_iunlock(ip, XFS_ILOCK_EXCL);
676 return error;
677 }
678
679 static inline bool
680 imap_needs_alloc(
681 struct inode *inode,
682 unsigned flags,
683 struct xfs_bmbt_irec *imap,
684 int nimaps)
685 {
686 /* don't allocate blocks when just zeroing */
687 if (flags & IOMAP_ZERO)
688 return false;
689 if (!nimaps ||
690 imap->br_startblock == HOLESTARTBLOCK ||
691 imap->br_startblock == DELAYSTARTBLOCK)
692 return true;
693 /* we convert unwritten extents before copying the data for DAX */
694 if ((flags & IOMAP_DAX) && imap->br_state == XFS_EXT_UNWRITTEN)
695 return true;
696 return false;
697 }
698
699 static inline bool
700 imap_needs_cow(
701 struct xfs_inode *ip,
702 unsigned int flags,
703 struct xfs_bmbt_irec *imap,
704 int nimaps)
705 {
706 if (!xfs_is_cow_inode(ip))
707 return false;
708
709 /* when zeroing we don't have to COW holes or unwritten extents */
710 if (flags & IOMAP_ZERO) {
711 if (!nimaps ||
712 imap->br_startblock == HOLESTARTBLOCK ||
713 imap->br_state == XFS_EXT_UNWRITTEN)
714 return false;
715 }
716
717 return true;
718 }
719
720 /*
721 * Extents not yet cached requires exclusive access, don't block for
722 * IOMAP_NOWAIT.
723 *
724 * This is basically an opencoded xfs_ilock_data_map_shared() call, but with
725 * support for IOMAP_NOWAIT.
726 */
727 static int
728 xfs_ilock_for_iomap(
729 struct xfs_inode *ip,
730 unsigned flags,
731 unsigned *lockmode)
732 {
733 if (flags & IOMAP_NOWAIT) {
734 if (xfs_need_iread_extents(&ip->i_df))
735 return -EAGAIN;
736 if (!xfs_ilock_nowait(ip, *lockmode))
737 return -EAGAIN;
738 } else {
739 if (xfs_need_iread_extents(&ip->i_df))
740 *lockmode = XFS_ILOCK_EXCL;
741 xfs_ilock(ip, *lockmode);
742 }
743
744 return 0;
745 }
746
747 /*
748 * Check that the imap we are going to return to the caller spans the entire
749 * range that the caller requested for the IO.
750 */
751 static bool
752 imap_spans_range(
753 struct xfs_bmbt_irec *imap,
754 xfs_fileoff_t offset_fsb,
755 xfs_fileoff_t end_fsb)
756 {
757 if (imap->br_startoff > offset_fsb)
758 return false;
759 if (imap->br_startoff + imap->br_blockcount < end_fsb)
760 return false;
761 return true;
762 }
763
764 static int
765 xfs_direct_write_iomap_begin(
766 struct inode *inode,
767 loff_t offset,
768 loff_t length,
769 unsigned flags,
770 struct iomap *iomap,
771 struct iomap *srcmap)
772 {
773 struct xfs_inode *ip = XFS_I(inode);
774 struct xfs_mount *mp = ip->i_mount;
775 struct xfs_bmbt_irec imap, cmap;
776 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
777 xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, length);
778 int nimaps = 1, error = 0;
779 bool shared = false;
780 u16 iomap_flags = 0;
781 unsigned int lockmode;
782 u64 seq;
783
784 ASSERT(flags & (IOMAP_WRITE | IOMAP_ZERO));
785
786 if (xfs_is_shutdown(mp))
787 return -EIO;
788
789 /*
790 * Writes that span EOF might trigger an IO size update on completion,
791 * so consider them to be dirty for the purposes of O_DSYNC even if
792 * there is no other metadata changes pending or have been made here.
793 */
794 if (offset + length > i_size_read(inode))
795 iomap_flags |= IOMAP_F_DIRTY;
796
797 /*
798 * COW writes may allocate delalloc space or convert unwritten COW
799 * extents, so we need to make sure to take the lock exclusively here.
800 */
801 if (xfs_is_cow_inode(ip))
802 lockmode = XFS_ILOCK_EXCL;
803 else
804 lockmode = XFS_ILOCK_SHARED;
805
806 relock:
807 error = xfs_ilock_for_iomap(ip, flags, &lockmode);
808 if (error)
809 return error;
810
811 /*
812 * The reflink iflag could have changed since the earlier unlocked
813 * check, check if it again and relock if needed.
814 */
815 if (xfs_is_cow_inode(ip) && lockmode == XFS_ILOCK_SHARED) {
816 xfs_iunlock(ip, lockmode);
817 lockmode = XFS_ILOCK_EXCL;
818 goto relock;
819 }
820
821 error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
822 &nimaps, 0);
823 if (error)
824 goto out_unlock;
825
826 if (imap_needs_cow(ip, flags, &imap, nimaps)) {
827 error = -EAGAIN;
828 if (flags & IOMAP_NOWAIT)
829 goto out_unlock;
830
831 /* may drop and re-acquire the ilock */
832 error = xfs_reflink_allocate_cow(ip, &imap, &cmap, &shared,
833 &lockmode,
834 (flags & IOMAP_DIRECT) || IS_DAX(inode));
835 if (error)
836 goto out_unlock;
837 if (shared)
838 goto out_found_cow;
839 end_fsb = imap.br_startoff + imap.br_blockcount;
840 length = XFS_FSB_TO_B(mp, end_fsb) - offset;
841 }
842
843 if (imap_needs_alloc(inode, flags, &imap, nimaps))
844 goto allocate_blocks;
845
846 /*
847 * NOWAIT and OVERWRITE I/O needs to span the entire requested I/O with
848 * a single map so that we avoid partial IO failures due to the rest of
849 * the I/O range not covered by this map triggering an EAGAIN condition
850 * when it is subsequently mapped and aborting the I/O.
851 */
852 if (flags & (IOMAP_NOWAIT | IOMAP_OVERWRITE_ONLY)) {
853 error = -EAGAIN;
854 if (!imap_spans_range(&imap, offset_fsb, end_fsb))
855 goto out_unlock;
856 }
857
858 /*
859 * For overwrite only I/O, we cannot convert unwritten extents without
860 * requiring sub-block zeroing. This can only be done under an
861 * exclusive IOLOCK, hence return -EAGAIN if this is not a written
862 * extent to tell the caller to try again.
863 */
864 if (flags & IOMAP_OVERWRITE_ONLY) {
865 error = -EAGAIN;
866 if (imap.br_state != XFS_EXT_NORM &&
867 ((offset | length) & mp->m_blockmask))
868 goto out_unlock;
869 }
870
871 seq = xfs_iomap_inode_sequence(ip, iomap_flags);
872 xfs_iunlock(ip, lockmode);
873 trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
874 return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, iomap_flags, seq);
875
876 allocate_blocks:
877 error = -EAGAIN;
878 if (flags & (IOMAP_NOWAIT | IOMAP_OVERWRITE_ONLY))
879 goto out_unlock;
880
881 /*
882 * We cap the maximum length we map to a sane size to keep the chunks
883 * of work done where somewhat symmetric with the work writeback does.
884 * This is a completely arbitrary number pulled out of thin air as a
885 * best guess for initial testing.
886 *
887 * Note that the values needs to be less than 32-bits wide until the
888 * lower level functions are updated.
889 */
890 length = min_t(loff_t, length, 1024 * PAGE_SIZE);
891 end_fsb = xfs_iomap_end_fsb(mp, offset, length);
892
893 if (offset + length > XFS_ISIZE(ip))
894 end_fsb = xfs_iomap_eof_align_last_fsb(ip, end_fsb);
895 else if (nimaps && imap.br_startblock == HOLESTARTBLOCK)
896 end_fsb = min(end_fsb, imap.br_startoff + imap.br_blockcount);
897 xfs_iunlock(ip, lockmode);
898
899 error = xfs_iomap_write_direct(ip, offset_fsb, end_fsb - offset_fsb,
900 flags, &imap, &seq);
901 if (error)
902 return error;
903
904 trace_xfs_iomap_alloc(ip, offset, length, XFS_DATA_FORK, &imap);
905 return xfs_bmbt_to_iomap(ip, iomap, &imap, flags,
906 iomap_flags | IOMAP_F_NEW, seq);
907
908 out_found_cow:
909 length = XFS_FSB_TO_B(mp, cmap.br_startoff + cmap.br_blockcount);
910 trace_xfs_iomap_found(ip, offset, length - offset, XFS_COW_FORK, &cmap);
911 if (imap.br_startblock != HOLESTARTBLOCK) {
912 seq = xfs_iomap_inode_sequence(ip, 0);
913 error = xfs_bmbt_to_iomap(ip, srcmap, &imap, flags, 0, seq);
914 if (error)
915 goto out_unlock;
916 }
917 seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
918 xfs_iunlock(ip, lockmode);
919 return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, IOMAP_F_SHARED, seq);
920
921 out_unlock:
922 if (lockmode)
923 xfs_iunlock(ip, lockmode);
924 return error;
925 }
926
927 const struct iomap_ops xfs_direct_write_iomap_ops = {
928 .iomap_begin = xfs_direct_write_iomap_begin,
929 };
930
931 static int
932 xfs_dax_write_iomap_end(
933 struct inode *inode,
934 loff_t pos,
935 loff_t length,
936 ssize_t written,
937 unsigned flags,
938 struct iomap *iomap)
939 {
940 struct xfs_inode *ip = XFS_I(inode);
941
942 if (!xfs_is_cow_inode(ip))
943 return 0;
944
945 if (!written) {
946 xfs_reflink_cancel_cow_range(ip, pos, length, true);
947 return 0;
948 }
949
950 return xfs_reflink_end_cow(ip, pos, written);
951 }
952
953 const struct iomap_ops xfs_dax_write_iomap_ops = {
954 .iomap_begin = xfs_direct_write_iomap_begin,
955 .iomap_end = xfs_dax_write_iomap_end,
956 };
957
958 static int
959 xfs_buffered_write_iomap_begin(
960 struct inode *inode,
961 loff_t offset,
962 loff_t count,
963 unsigned flags,
964 struct iomap *iomap,
965 struct iomap *srcmap)
966 {
967 struct xfs_inode *ip = XFS_I(inode);
968 struct xfs_mount *mp = ip->i_mount;
969 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
970 xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, count);
971 struct xfs_bmbt_irec imap, cmap;
972 struct xfs_iext_cursor icur, ccur;
973 xfs_fsblock_t prealloc_blocks = 0;
974 bool eof = false, cow_eof = false, shared = false;
975 int allocfork = XFS_DATA_FORK;
976 int error = 0;
977 unsigned int lockmode = XFS_ILOCK_EXCL;
978 u64 seq;
979
980 if (xfs_is_shutdown(mp))
981 return -EIO;
982
983 /* we can't use delayed allocations when using extent size hints */
984 if (xfs_get_extsz_hint(ip))
985 return xfs_direct_write_iomap_begin(inode, offset, count,
986 flags, iomap, srcmap);
987
988 error = xfs_qm_dqattach(ip);
989 if (error)
990 return error;
991
992 error = xfs_ilock_for_iomap(ip, flags, &lockmode);
993 if (error)
994 return error;
995
996 if (XFS_IS_CORRUPT(mp, !xfs_ifork_has_extents(&ip->i_df)) ||
997 XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BMAPIFORMAT)) {
998 xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
999 error = -EFSCORRUPTED;
1000 goto out_unlock;
1001 }
1002
1003 XFS_STATS_INC(mp, xs_blk_mapw);
1004
1005 error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
1006 if (error)
1007 goto out_unlock;
1008
1009 /*
1010 * Search the data fork first to look up our source mapping. We
1011 * always need the data fork map, as we have to return it to the
1012 * iomap code so that the higher level write code can read data in to
1013 * perform read-modify-write cycles for unaligned writes.
1014 */
1015 eof = !xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap);
1016 if (eof)
1017 imap.br_startoff = end_fsb; /* fake hole until the end */
1018
1019 /* We never need to allocate blocks for zeroing or unsharing a hole. */
1020 if ((flags & (IOMAP_UNSHARE | IOMAP_ZERO)) &&
1021 imap.br_startoff > offset_fsb) {
1022 xfs_hole_to_iomap(ip, iomap, offset_fsb, imap.br_startoff);
1023 goto out_unlock;
1024 }
1025
1026 /*
1027 * For zeroing, trim a delalloc extent that extends beyond the EOF
1028 * block. If it starts beyond the EOF block, convert it to an
1029 * unwritten extent.
1030 */
1031 if ((flags & IOMAP_ZERO) && imap.br_startoff <= offset_fsb &&
1032 isnullstartblock(imap.br_startblock)) {
1033 xfs_fileoff_t eof_fsb = XFS_B_TO_FSB(mp, XFS_ISIZE(ip));
1034
1035 if (offset_fsb >= eof_fsb)
1036 goto convert_delay;
1037 if (end_fsb > eof_fsb) {
1038 end_fsb = eof_fsb;
1039 xfs_trim_extent(&imap, offset_fsb,
1040 end_fsb - offset_fsb);
1041 }
1042 }
1043
1044 /*
1045 * Search the COW fork extent list even if we did not find a data fork
1046 * extent. This serves two purposes: first this implements the
1047 * speculative preallocation using cowextsize, so that we also unshare
1048 * block adjacent to shared blocks instead of just the shared blocks
1049 * themselves. Second the lookup in the extent list is generally faster
1050 * than going out to the shared extent tree.
1051 */
1052 if (xfs_is_cow_inode(ip)) {
1053 if (!ip->i_cowfp) {
1054 ASSERT(!xfs_is_reflink_inode(ip));
1055 xfs_ifork_init_cow(ip);
1056 }
1057 cow_eof = !xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb,
1058 &ccur, &cmap);
1059 if (!cow_eof && cmap.br_startoff <= offset_fsb) {
1060 trace_xfs_reflink_cow_found(ip, &cmap);
1061 goto found_cow;
1062 }
1063 }
1064
1065 if (imap.br_startoff <= offset_fsb) {
1066 /*
1067 * For reflink files we may need a delalloc reservation when
1068 * overwriting shared extents. This includes zeroing of
1069 * existing extents that contain data.
1070 */
1071 if (!xfs_is_cow_inode(ip) ||
1072 ((flags & IOMAP_ZERO) && imap.br_state != XFS_EXT_NORM)) {
1073 trace_xfs_iomap_found(ip, offset, count, XFS_DATA_FORK,
1074 &imap);
1075 goto found_imap;
1076 }
1077
1078 xfs_trim_extent(&imap, offset_fsb, end_fsb - offset_fsb);
1079
1080 /* Trim the mapping to the nearest shared extent boundary. */
1081 error = xfs_bmap_trim_cow(ip, &imap, &shared);
1082 if (error)
1083 goto out_unlock;
1084
1085 /* Not shared? Just report the (potentially capped) extent. */
1086 if (!shared) {
1087 trace_xfs_iomap_found(ip, offset, count, XFS_DATA_FORK,
1088 &imap);
1089 goto found_imap;
1090 }
1091
1092 /*
1093 * Fork all the shared blocks from our write offset until the
1094 * end of the extent.
1095 */
1096 allocfork = XFS_COW_FORK;
1097 end_fsb = imap.br_startoff + imap.br_blockcount;
1098 } else {
1099 /*
1100 * We cap the maximum length we map here to MAX_WRITEBACK_PAGES
1101 * pages to keep the chunks of work done where somewhat
1102 * symmetric with the work writeback does. This is a completely
1103 * arbitrary number pulled out of thin air.
1104 *
1105 * Note that the values needs to be less than 32-bits wide until
1106 * the lower level functions are updated.
1107 */
1108 count = min_t(loff_t, count, 1024 * PAGE_SIZE);
1109 end_fsb = xfs_iomap_end_fsb(mp, offset, count);
1110
1111 if (xfs_is_always_cow_inode(ip))
1112 allocfork = XFS_COW_FORK;
1113 }
1114
1115 if (eof && offset + count > XFS_ISIZE(ip)) {
1116 /*
1117 * Determine the initial size of the preallocation.
1118 * We clean up any extra preallocation when the file is closed.
1119 */
1120 if (xfs_has_allocsize(mp))
1121 prealloc_blocks = mp->m_allocsize_blocks;
1122 else if (allocfork == XFS_DATA_FORK)
1123 prealloc_blocks = xfs_iomap_prealloc_size(ip, allocfork,
1124 offset, count, &icur);
1125 else
1126 prealloc_blocks = xfs_iomap_prealloc_size(ip, allocfork,
1127 offset, count, &ccur);
1128 if (prealloc_blocks) {
1129 xfs_extlen_t align;
1130 xfs_off_t end_offset;
1131 xfs_fileoff_t p_end_fsb;
1132
1133 end_offset = XFS_ALLOC_ALIGN(mp, offset + count - 1);
1134 p_end_fsb = XFS_B_TO_FSBT(mp, end_offset) +
1135 prealloc_blocks;
1136
1137 align = xfs_eof_alignment(ip);
1138 if (align)
1139 p_end_fsb = roundup_64(p_end_fsb, align);
1140
1141 p_end_fsb = min(p_end_fsb,
1142 XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
1143 ASSERT(p_end_fsb > offset_fsb);
1144 prealloc_blocks = p_end_fsb - end_fsb;
1145 }
1146 }
1147
1148 if (allocfork == XFS_COW_FORK) {
1149 error = xfs_bmapi_reserve_delalloc(ip, allocfork, offset_fsb,
1150 end_fsb - offset_fsb, prealloc_blocks, &cmap,
1151 &ccur, cow_eof);
1152 if (error)
1153 goto out_unlock;
1154
1155 trace_xfs_iomap_alloc(ip, offset, count, allocfork, &cmap);
1156 goto found_cow;
1157 }
1158
1159 error = xfs_bmapi_reserve_delalloc(ip, allocfork, offset_fsb,
1160 end_fsb - offset_fsb, prealloc_blocks, &imap, &icur,
1161 eof);
1162 if (error)
1163 goto out_unlock;
1164
1165 /*
1166 * Flag newly allocated delalloc blocks with IOMAP_F_NEW so we punch
1167 * them out if the write happens to fail.
1168 */
1169 seq = xfs_iomap_inode_sequence(ip, IOMAP_F_NEW);
1170 xfs_iunlock(ip, lockmode);
1171 trace_xfs_iomap_alloc(ip, offset, count, allocfork, &imap);
1172 return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, IOMAP_F_NEW, seq);
1173
1174 found_imap:
1175 seq = xfs_iomap_inode_sequence(ip, 0);
1176 xfs_iunlock(ip, lockmode);
1177 return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0, seq);
1178
1179 convert_delay:
1180 xfs_iunlock(ip, lockmode);
1181 truncate_pagecache(inode, offset);
1182 error = xfs_bmapi_convert_delalloc(ip, XFS_DATA_FORK, offset,
1183 iomap, NULL);
1184 if (error)
1185 return error;
1186
1187 trace_xfs_iomap_alloc(ip, offset, count, XFS_DATA_FORK, &imap);
1188 return 0;
1189
1190 found_cow:
1191 seq = xfs_iomap_inode_sequence(ip, 0);
1192 if (imap.br_startoff <= offset_fsb) {
1193 error = xfs_bmbt_to_iomap(ip, srcmap, &imap, flags, 0, seq);
1194 if (error)
1195 goto out_unlock;
1196 seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
1197 xfs_iunlock(ip, lockmode);
1198 return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
1199 IOMAP_F_SHARED, seq);
1200 }
1201
1202 xfs_trim_extent(&cmap, offset_fsb, imap.br_startoff - offset_fsb);
1203 xfs_iunlock(ip, lockmode);
1204 return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, 0, seq);
1205
1206 out_unlock:
1207 xfs_iunlock(ip, lockmode);
1208 return error;
1209 }
1210
1211 static int
1212 xfs_buffered_write_delalloc_punch(
1213 struct inode *inode,
1214 loff_t offset,
1215 loff_t length)
1216 {
1217 xfs_bmap_punch_delalloc_range(XFS_I(inode), offset, offset + length);
1218 return 0;
1219 }
1220
1221 static int
1222 xfs_buffered_write_iomap_end(
1223 struct inode *inode,
1224 loff_t offset,
1225 loff_t length,
1226 ssize_t written,
1227 unsigned flags,
1228 struct iomap *iomap)
1229 {
1230
1231 struct xfs_mount *mp = XFS_M(inode->i_sb);
1232 int error;
1233
1234 error = iomap_file_buffered_write_punch_delalloc(inode, iomap, offset,
1235 length, written, &xfs_buffered_write_delalloc_punch);
1236 if (error && !xfs_is_shutdown(mp)) {
1237 xfs_alert(mp, "%s: unable to clean up ino 0x%llx",
1238 __func__, XFS_I(inode)->i_ino);
1239 return error;
1240 }
1241 return 0;
1242 }
1243
1244 const struct iomap_ops xfs_buffered_write_iomap_ops = {
1245 .iomap_begin = xfs_buffered_write_iomap_begin,
1246 .iomap_end = xfs_buffered_write_iomap_end,
1247 };
1248
1249 /*
1250 * iomap_page_mkwrite() will never fail in a way that requires delalloc extents
1251 * that it allocated to be revoked. Hence we do not need an .iomap_end method
1252 * for this operation.
1253 */
1254 const struct iomap_ops xfs_page_mkwrite_iomap_ops = {
1255 .iomap_begin = xfs_buffered_write_iomap_begin,
1256 };
1257
1258 static int
1259 xfs_read_iomap_begin(
1260 struct inode *inode,
1261 loff_t offset,
1262 loff_t length,
1263 unsigned flags,
1264 struct iomap *iomap,
1265 struct iomap *srcmap)
1266 {
1267 struct xfs_inode *ip = XFS_I(inode);
1268 struct xfs_mount *mp = ip->i_mount;
1269 struct xfs_bmbt_irec imap;
1270 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
1271 xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, length);
1272 int nimaps = 1, error = 0;
1273 bool shared = false;
1274 unsigned int lockmode = XFS_ILOCK_SHARED;
1275 u64 seq;
1276
1277 ASSERT(!(flags & (IOMAP_WRITE | IOMAP_ZERO)));
1278
1279 if (xfs_is_shutdown(mp))
1280 return -EIO;
1281
1282 error = xfs_ilock_for_iomap(ip, flags, &lockmode);
1283 if (error)
1284 return error;
1285 error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
1286 &nimaps, 0);
1287 if (!error && ((flags & IOMAP_REPORT) || IS_DAX(inode)))
1288 error = xfs_reflink_trim_around_shared(ip, &imap, &shared);
1289 seq = xfs_iomap_inode_sequence(ip, shared ? IOMAP_F_SHARED : 0);
1290 xfs_iunlock(ip, lockmode);
1291
1292 if (error)
1293 return error;
1294 trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
1295 return xfs_bmbt_to_iomap(ip, iomap, &imap, flags,
1296 shared ? IOMAP_F_SHARED : 0, seq);
1297 }
1298
1299 const struct iomap_ops xfs_read_iomap_ops = {
1300 .iomap_begin = xfs_read_iomap_begin,
1301 };
1302
1303 static int
1304 xfs_seek_iomap_begin(
1305 struct inode *inode,
1306 loff_t offset,
1307 loff_t length,
1308 unsigned flags,
1309 struct iomap *iomap,
1310 struct iomap *srcmap)
1311 {
1312 struct xfs_inode *ip = XFS_I(inode);
1313 struct xfs_mount *mp = ip->i_mount;
1314 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
1315 xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + length);
1316 xfs_fileoff_t cow_fsb = NULLFILEOFF, data_fsb = NULLFILEOFF;
1317 struct xfs_iext_cursor icur;
1318 struct xfs_bmbt_irec imap, cmap;
1319 int error = 0;
1320 unsigned lockmode;
1321 u64 seq;
1322
1323 if (xfs_is_shutdown(mp))
1324 return -EIO;
1325
1326 lockmode = xfs_ilock_data_map_shared(ip);
1327 error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
1328 if (error)
1329 goto out_unlock;
1330
1331 if (xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap)) {
1332 /*
1333 * If we found a data extent we are done.
1334 */
1335 if (imap.br_startoff <= offset_fsb)
1336 goto done;
1337 data_fsb = imap.br_startoff;
1338 } else {
1339 /*
1340 * Fake a hole until the end of the file.
1341 */
1342 data_fsb = xfs_iomap_end_fsb(mp, offset, length);
1343 }
1344
1345 /*
1346 * If a COW fork extent covers the hole, report it - capped to the next
1347 * data fork extent:
1348 */
1349 if (xfs_inode_has_cow_data(ip) &&
1350 xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &cmap))
1351 cow_fsb = cmap.br_startoff;
1352 if (cow_fsb != NULLFILEOFF && cow_fsb <= offset_fsb) {
1353 if (data_fsb < cow_fsb + cmap.br_blockcount)
1354 end_fsb = min(end_fsb, data_fsb);
1355 xfs_trim_extent(&cmap, offset_fsb, end_fsb - offset_fsb);
1356 seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
1357 error = xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
1358 IOMAP_F_SHARED, seq);
1359 /*
1360 * This is a COW extent, so we must probe the page cache
1361 * because there could be dirty page cache being backed
1362 * by this extent.
1363 */
1364 iomap->type = IOMAP_UNWRITTEN;
1365 goto out_unlock;
1366 }
1367
1368 /*
1369 * Else report a hole, capped to the next found data or COW extent.
1370 */
1371 if (cow_fsb != NULLFILEOFF && cow_fsb < data_fsb)
1372 imap.br_blockcount = cow_fsb - offset_fsb;
1373 else
1374 imap.br_blockcount = data_fsb - offset_fsb;
1375 imap.br_startoff = offset_fsb;
1376 imap.br_startblock = HOLESTARTBLOCK;
1377 imap.br_state = XFS_EXT_NORM;
1378 done:
1379 seq = xfs_iomap_inode_sequence(ip, 0);
1380 xfs_trim_extent(&imap, offset_fsb, end_fsb - offset_fsb);
1381 error = xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0, seq);
1382 out_unlock:
1383 xfs_iunlock(ip, lockmode);
1384 return error;
1385 }
1386
1387 const struct iomap_ops xfs_seek_iomap_ops = {
1388 .iomap_begin = xfs_seek_iomap_begin,
1389 };
1390
1391 static int
1392 xfs_xattr_iomap_begin(
1393 struct inode *inode,
1394 loff_t offset,
1395 loff_t length,
1396 unsigned flags,
1397 struct iomap *iomap,
1398 struct iomap *srcmap)
1399 {
1400 struct xfs_inode *ip = XFS_I(inode);
1401 struct xfs_mount *mp = ip->i_mount;
1402 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
1403 xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + length);
1404 struct xfs_bmbt_irec imap;
1405 int nimaps = 1, error = 0;
1406 unsigned lockmode;
1407 int seq;
1408
1409 if (xfs_is_shutdown(mp))
1410 return -EIO;
1411
1412 lockmode = xfs_ilock_attr_map_shared(ip);
1413
1414 /* if there are no attribute fork or extents, return ENOENT */
1415 if (!xfs_inode_has_attr_fork(ip) || !ip->i_af.if_nextents) {
1416 error = -ENOENT;
1417 goto out_unlock;
1418 }
1419
1420 ASSERT(ip->i_af.if_format != XFS_DINODE_FMT_LOCAL);
1421 error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
1422 &nimaps, XFS_BMAPI_ATTRFORK);
1423 out_unlock:
1424
1425 seq = xfs_iomap_inode_sequence(ip, IOMAP_F_XATTR);
1426 xfs_iunlock(ip, lockmode);
1427
1428 if (error)
1429 return error;
1430 ASSERT(nimaps);
1431 return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, IOMAP_F_XATTR, seq);
1432 }
1433
1434 const struct iomap_ops xfs_xattr_iomap_ops = {
1435 .iomap_begin = xfs_xattr_iomap_begin,
1436 };
1437
1438 int
1439 xfs_zero_range(
1440 struct xfs_inode *ip,
1441 loff_t pos,
1442 loff_t len,
1443 bool *did_zero)
1444 {
1445 struct inode *inode = VFS_I(ip);
1446
1447 if (IS_DAX(inode))
1448 return dax_zero_range(inode, pos, len, did_zero,
1449 &xfs_dax_write_iomap_ops);
1450 return iomap_zero_range(inode, pos, len, did_zero,
1451 &xfs_buffered_write_iomap_ops);
1452 }
1453
1454 int
1455 xfs_truncate_page(
1456 struct xfs_inode *ip,
1457 loff_t pos,
1458 bool *did_zero)
1459 {
1460 struct inode *inode = VFS_I(ip);
1461
1462 if (IS_DAX(inode))
1463 return dax_truncate_page(inode, pos, did_zero,
1464 &xfs_dax_write_iomap_ops);
1465 return iomap_truncate_page(inode, pos, did_zero,
1466 &xfs_buffered_write_iomap_ops);
1467 }
1468
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