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