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