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Merge patch series "riscv: Extension parsing fixes"
[linux.git] / fs / xfs / xfs_iomap.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2000-2006 Silicon Graphics, Inc.
4  * Copyright (c) 2016-2018 Christoph Hellwig.
5  * All Rights Reserved.
6  */
7 #include "xfs.h"
8 #include "xfs_fs.h"
9 #include "xfs_shared.h"
10 #include "xfs_format.h"
11 #include "xfs_log_format.h"
12 #include "xfs_trans_resv.h"
13 #include "xfs_mount.h"
14 #include "xfs_inode.h"
15 #include "xfs_btree.h"
16 #include "xfs_bmap_btree.h"
17 #include "xfs_bmap.h"
18 #include "xfs_bmap_util.h"
19 #include "xfs_errortag.h"
20 #include "xfs_error.h"
21 #include "xfs_trans.h"
22 #include "xfs_trans_space.h"
23 #include "xfs_inode_item.h"
24 #include "xfs_iomap.h"
25 #include "xfs_trace.h"
26 #include "xfs_quota.h"
27 #include "xfs_dquot_item.h"
28 #include "xfs_dquot.h"
29 #include "xfs_reflink.h"
30 #include "xfs_health.h"
31 #include "xfs_rtbitmap.h"
32
33 #define XFS_ALLOC_ALIGN(mp, off) \
34         (((off) >> mp->m_allocsize_log) << mp->m_allocsize_log)
35
36 static int
37 xfs_alert_fsblock_zero(
38         xfs_inode_t     *ip,
39         xfs_bmbt_irec_t *imap)
40 {
41         xfs_alert_tag(ip->i_mount, XFS_PTAG_FSBLOCK_ZERO,
42                         "Access to block zero in inode %llu "
43                         "start_block: %llx start_off: %llx "
44                         "blkcnt: %llx extent-state: %x",
45                 (unsigned long long)ip->i_ino,
46                 (unsigned long long)imap->br_startblock,
47                 (unsigned long long)imap->br_startoff,
48                 (unsigned long long)imap->br_blockcount,
49                 imap->br_state);
50         xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
51         return -EFSCORRUPTED;
52 }
53
54 u64
55 xfs_iomap_inode_sequence(
56         struct xfs_inode        *ip,
57         u16                     iomap_flags)
58 {
59         u64                     cookie = 0;
60
61         if (iomap_flags & IOMAP_F_XATTR)
62                 return READ_ONCE(ip->i_af.if_seq);
63         if ((iomap_flags & IOMAP_F_SHARED) && ip->i_cowfp)
64                 cookie = (u64)READ_ONCE(ip->i_cowfp->if_seq) << 32;
65         return cookie | READ_ONCE(ip->i_df.if_seq);
66 }
67
68 /*
69  * Check that the iomap passed to us is still valid for the given offset and
70  * length.
71  */
72 static bool
73 xfs_iomap_valid(
74         struct inode            *inode,
75         const struct iomap      *iomap)
76 {
77         struct xfs_inode        *ip = XFS_I(inode);
78
79         if (iomap->validity_cookie !=
80                         xfs_iomap_inode_sequence(ip, iomap->flags)) {
81                 trace_xfs_iomap_invalid(ip, iomap);
82                 return false;
83         }
84
85         XFS_ERRORTAG_DELAY(ip->i_mount, XFS_ERRTAG_WRITE_DELAY_MS);
86         return true;
87 }
88
89 static const struct iomap_folio_ops xfs_iomap_folio_ops = {
90         .iomap_valid            = xfs_iomap_valid,
91 };
92
93 int
94 xfs_bmbt_to_iomap(
95         struct xfs_inode        *ip,
96         struct iomap            *iomap,
97         struct xfs_bmbt_irec    *imap,
98         unsigned int            mapping_flags,
99         u16                     iomap_flags,
100         u64                     sequence_cookie)
101 {
102         struct xfs_mount        *mp = ip->i_mount;
103         struct xfs_buftarg      *target = xfs_inode_buftarg(ip);
104
105         if (unlikely(!xfs_valid_startblock(ip, imap->br_startblock))) {
106                 xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
107                 return xfs_alert_fsblock_zero(ip, imap);
108         }
109
110         if (imap->br_startblock == HOLESTARTBLOCK) {
111                 iomap->addr = IOMAP_NULL_ADDR;
112                 iomap->type = IOMAP_HOLE;
113         } else if (imap->br_startblock == DELAYSTARTBLOCK ||
114                    isnullstartblock(imap->br_startblock)) {
115                 iomap->addr = IOMAP_NULL_ADDR;
116                 iomap->type = IOMAP_DELALLOC;
117         } else {
118                 iomap->addr = BBTOB(xfs_fsb_to_db(ip, imap->br_startblock));
119                 if (mapping_flags & IOMAP_DAX)
120                         iomap->addr += target->bt_dax_part_off;
121
122                 if (imap->br_state == XFS_EXT_UNWRITTEN)
123                         iomap->type = IOMAP_UNWRITTEN;
124                 else
125                         iomap->type = IOMAP_MAPPED;
126
127         }
128         iomap->offset = XFS_FSB_TO_B(mp, imap->br_startoff);
129         iomap->length = XFS_FSB_TO_B(mp, imap->br_blockcount);
130         if (mapping_flags & IOMAP_DAX)
131                 iomap->dax_dev = target->bt_daxdev;
132         else
133                 iomap->bdev = target->bt_bdev;
134         iomap->flags = iomap_flags;
135
136         if (xfs_ipincount(ip) &&
137             (ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
138                 iomap->flags |= IOMAP_F_DIRTY;
139
140         iomap->validity_cookie = sequence_cookie;
141         iomap->folio_ops = &xfs_iomap_folio_ops;
142         return 0;
143 }
144
145 static void
146 xfs_hole_to_iomap(
147         struct xfs_inode        *ip,
148         struct iomap            *iomap,
149         xfs_fileoff_t           offset_fsb,
150         xfs_fileoff_t           end_fsb)
151 {
152         struct xfs_buftarg      *target = xfs_inode_buftarg(ip);
153
154         iomap->addr = IOMAP_NULL_ADDR;
155         iomap->type = IOMAP_HOLE;
156         iomap->offset = XFS_FSB_TO_B(ip->i_mount, offset_fsb);
157         iomap->length = XFS_FSB_TO_B(ip->i_mount, end_fsb - offset_fsb);
158         iomap->bdev = target->bt_bdev;
159         iomap->dax_dev = target->bt_daxdev;
160 }
161
162 static inline xfs_fileoff_t
163 xfs_iomap_end_fsb(
164         struct xfs_mount        *mp,
165         loff_t                  offset,
166         loff_t                  count)
167 {
168         ASSERT(offset <= mp->m_super->s_maxbytes);
169         return min(XFS_B_TO_FSB(mp, offset + count),
170                    XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
171 }
172
173 static xfs_extlen_t
174 xfs_eof_alignment(
175         struct xfs_inode        *ip)
176 {
177         struct xfs_mount        *mp = ip->i_mount;
178         xfs_extlen_t            align = 0;
179
180         if (!XFS_IS_REALTIME_INODE(ip)) {
181                 /*
182                  * Round up the allocation request to a stripe unit
183                  * (m_dalign) boundary if the file size is >= stripe unit
184                  * size, and we are allocating past the allocation eof.
185                  *
186                  * If mounted with the "-o swalloc" option the alignment is
187                  * increased from the strip unit size to the stripe width.
188                  */
189                 if (mp->m_swidth && xfs_has_swalloc(mp))
190                         align = mp->m_swidth;
191                 else if (mp->m_dalign)
192                         align = mp->m_dalign;
193
194                 if (align && XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, align))
195                         align = 0;
196         }
197
198         return align;
199 }
200
201 /*
202  * Check if last_fsb is outside the last extent, and if so grow it to the next
203  * stripe unit boundary.
204  */
205 xfs_fileoff_t
206 xfs_iomap_eof_align_last_fsb(
207         struct xfs_inode        *ip,
208         xfs_fileoff_t           end_fsb)
209 {
210         struct xfs_ifork        *ifp = xfs_ifork_ptr(ip, XFS_DATA_FORK);
211         xfs_extlen_t            extsz = xfs_get_extsz_hint(ip);
212         xfs_extlen_t            align = xfs_eof_alignment(ip);
213         struct xfs_bmbt_irec    irec;
214         struct xfs_iext_cursor  icur;
215
216         ASSERT(!xfs_need_iread_extents(ifp));
217
218         /*
219          * Always round up the allocation request to the extent hint boundary.
220          */
221         if (extsz) {
222                 if (align)
223                         align = roundup_64(align, extsz);
224                 else
225                         align = extsz;
226         }
227
228         if (align) {
229                 xfs_fileoff_t   aligned_end_fsb = roundup_64(end_fsb, align);
230
231                 xfs_iext_last(ifp, &icur);
232                 if (!xfs_iext_get_extent(ifp, &icur, &irec) ||
233                     aligned_end_fsb >= irec.br_startoff + irec.br_blockcount)
234                         return aligned_end_fsb;
235         }
236
237         return end_fsb;
238 }
239
240 int
241 xfs_iomap_write_direct(
242         struct xfs_inode        *ip,
243         xfs_fileoff_t           offset_fsb,
244         xfs_fileoff_t           count_fsb,
245         unsigned int            flags,
246         struct xfs_bmbt_irec    *imap,
247         u64                     *seq)
248 {
249         struct xfs_mount        *mp = ip->i_mount;
250         struct xfs_trans        *tp;
251         xfs_filblks_t           resaligned;
252         int                     nimaps;
253         unsigned int            dblocks, rblocks;
254         bool                    force = false;
255         int                     error;
256         int                     bmapi_flags = XFS_BMAPI_PREALLOC;
257         int                     nr_exts = XFS_IEXT_ADD_NOSPLIT_CNT;
258
259         ASSERT(count_fsb > 0);
260
261         resaligned = xfs_aligned_fsb_count(offset_fsb, count_fsb,
262                                            xfs_get_extsz_hint(ip));
263         if (unlikely(XFS_IS_REALTIME_INODE(ip))) {
264                 dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
265                 rblocks = resaligned;
266         } else {
267                 dblocks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
268                 rblocks = 0;
269         }
270
271         error = xfs_qm_dqattach(ip);
272         if (error)
273                 return error;
274
275         /*
276          * For DAX, we do not allocate unwritten extents, but instead we zero
277          * the block before we commit the transaction.  Ideally we'd like to do
278          * this outside the transaction context, but if we commit and then crash
279          * we may not have zeroed the blocks and this will be exposed on
280          * recovery of the allocation. Hence we must zero before commit.
281          *
282          * Further, if we are mapping unwritten extents here, we need to zero
283          * and convert them to written so that we don't need an unwritten extent
284          * callback for DAX. This also means that we need to be able to dip into
285          * the reserve block pool for bmbt block allocation if there is no space
286          * left but we need to do unwritten extent conversion.
287          */
288         if (flags & IOMAP_DAX) {
289                 bmapi_flags = XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO;
290                 if (imap->br_state == XFS_EXT_UNWRITTEN) {
291                         force = true;
292                         nr_exts = XFS_IEXT_WRITE_UNWRITTEN_CNT;
293                         dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
294                 }
295         }
296
297         error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, dblocks,
298                         rblocks, force, &tp);
299         if (error)
300                 return error;
301
302         error = xfs_iext_count_extend(tp, ip, XFS_DATA_FORK, nr_exts);
303         if (error)
304                 goto out_trans_cancel;
305
306         /*
307          * From this point onwards we overwrite the imap pointer that the
308          * caller gave to us.
309          */
310         nimaps = 1;
311         error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb, bmapi_flags, 0,
312                                 imap, &nimaps);
313         if (error)
314                 goto out_trans_cancel;
315
316         /*
317          * Complete the transaction
318          */
319         error = xfs_trans_commit(tp);
320         if (error)
321                 goto out_unlock;
322
323         if (unlikely(!xfs_valid_startblock(ip, imap->br_startblock))) {
324                 xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
325                 error = xfs_alert_fsblock_zero(ip, imap);
326         }
327
328 out_unlock:
329         *seq = xfs_iomap_inode_sequence(ip, 0);
330         xfs_iunlock(ip, XFS_ILOCK_EXCL);
331         return error;
332
333 out_trans_cancel:
334         xfs_trans_cancel(tp);
335         goto out_unlock;
336 }
337
338 STATIC bool
339 xfs_quota_need_throttle(
340         struct xfs_inode        *ip,
341         xfs_dqtype_t            type,
342         xfs_fsblock_t           alloc_blocks)
343 {
344         struct xfs_dquot        *dq = xfs_inode_dquot(ip, type);
345
346         if (!dq || !xfs_this_quota_on(ip->i_mount, type))
347                 return false;
348
349         /* no hi watermark, no throttle */
350         if (!dq->q_prealloc_hi_wmark)
351                 return false;
352
353         /* under the lo watermark, no throttle */
354         if (dq->q_blk.reserved + alloc_blocks < dq->q_prealloc_lo_wmark)
355                 return false;
356
357         return true;
358 }
359
360 STATIC void
361 xfs_quota_calc_throttle(
362         struct xfs_inode        *ip,
363         xfs_dqtype_t            type,
364         xfs_fsblock_t           *qblocks,
365         int                     *qshift,
366         int64_t                 *qfreesp)
367 {
368         struct xfs_dquot        *dq = xfs_inode_dquot(ip, type);
369         int64_t                 freesp;
370         int                     shift = 0;
371
372         /* no dq, or over hi wmark, squash the prealloc completely */
373         if (!dq || dq->q_blk.reserved >= dq->q_prealloc_hi_wmark) {
374                 *qblocks = 0;
375                 *qfreesp = 0;
376                 return;
377         }
378
379         freesp = dq->q_prealloc_hi_wmark - dq->q_blk.reserved;
380         if (freesp < dq->q_low_space[XFS_QLOWSP_5_PCNT]) {
381                 shift = 2;
382                 if (freesp < dq->q_low_space[XFS_QLOWSP_3_PCNT])
383                         shift += 2;
384                 if (freesp < dq->q_low_space[XFS_QLOWSP_1_PCNT])
385                         shift += 2;
386         }
387
388         if (freesp < *qfreesp)
389                 *qfreesp = freesp;
390
391         /* only overwrite the throttle values if we are more aggressive */
392         if ((freesp >> shift) < (*qblocks >> *qshift)) {
393                 *qblocks = freesp;
394                 *qshift = shift;
395         }
396 }
397
398 static int64_t
399 xfs_iomap_freesp(
400         struct percpu_counter   *counter,
401         uint64_t                low_space[XFS_LOWSP_MAX],
402         int                     *shift)
403 {
404         int64_t                 freesp;
405
406         freesp = percpu_counter_read_positive(counter);
407         if (freesp < low_space[XFS_LOWSP_5_PCNT]) {
408                 *shift = 2;
409                 if (freesp < low_space[XFS_LOWSP_4_PCNT])
410                         (*shift)++;
411                 if (freesp < low_space[XFS_LOWSP_3_PCNT])
412                         (*shift)++;
413                 if (freesp < low_space[XFS_LOWSP_2_PCNT])
414                         (*shift)++;
415                 if (freesp < low_space[XFS_LOWSP_1_PCNT])
416                         (*shift)++;
417         }
418         return freesp;
419 }
420
421 /*
422  * If we don't have a user specified preallocation size, dynamically increase
423  * the preallocation size as the size of the file grows.  Cap the maximum size
424  * at a single extent or less if the filesystem is near full. The closer the
425  * filesystem is to being full, the smaller the maximum preallocation.
426  */
427 STATIC xfs_fsblock_t
428 xfs_iomap_prealloc_size(
429         struct xfs_inode        *ip,
430         int                     whichfork,
431         loff_t                  offset,
432         loff_t                  count,
433         struct xfs_iext_cursor  *icur)
434 {
435         struct xfs_iext_cursor  ncur = *icur;
436         struct xfs_bmbt_irec    prev, got;
437         struct xfs_mount        *mp = ip->i_mount;
438         struct xfs_ifork        *ifp = xfs_ifork_ptr(ip, whichfork);
439         xfs_fileoff_t           offset_fsb = XFS_B_TO_FSBT(mp, offset);
440         int64_t                 freesp;
441         xfs_fsblock_t           qblocks;
442         xfs_fsblock_t           alloc_blocks = 0;
443         xfs_extlen_t            plen;
444         int                     shift = 0;
445         int                     qshift = 0;
446
447         /*
448          * As an exception we don't do any preallocation at all if the file is
449          * smaller than the minimum preallocation and we are using the default
450          * dynamic preallocation scheme, as it is likely this is the only write
451          * to the file that is going to be done.
452          */
453         if (XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_allocsize_blocks))
454                 return 0;
455
456         /*
457          * Use the minimum preallocation size for small files or if we are
458          * writing right after a hole.
459          */
460         if (XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_dalign) ||
461             !xfs_iext_prev_extent(ifp, &ncur, &prev) ||
462             prev.br_startoff + prev.br_blockcount < offset_fsb)
463                 return mp->m_allocsize_blocks;
464
465         /*
466          * Take the size of the preceding data extents as the basis for the
467          * preallocation size. Note that we don't care if the previous extents
468          * are written or not.
469          */
470         plen = prev.br_blockcount;
471         while (xfs_iext_prev_extent(ifp, &ncur, &got)) {
472                 if (plen > XFS_MAX_BMBT_EXTLEN / 2 ||
473                     isnullstartblock(got.br_startblock) ||
474                     got.br_startoff + got.br_blockcount != prev.br_startoff ||
475                     got.br_startblock + got.br_blockcount != prev.br_startblock)
476                         break;
477                 plen += got.br_blockcount;
478                 prev = got;
479         }
480
481         /*
482          * If the size of the extents is greater than half the maximum extent
483          * length, then use the current offset as the basis.  This ensures that
484          * for large files the preallocation size always extends to
485          * XFS_BMBT_MAX_EXTLEN rather than falling short due to things like stripe
486          * unit/width alignment of real extents.
487          */
488         alloc_blocks = plen * 2;
489         if (alloc_blocks > XFS_MAX_BMBT_EXTLEN)
490                 alloc_blocks = XFS_B_TO_FSB(mp, offset);
491         qblocks = alloc_blocks;
492
493         /*
494          * XFS_BMBT_MAX_EXTLEN is not a power of two value but we round the prealloc
495          * down to the nearest power of two value after throttling. To prevent
496          * the round down from unconditionally reducing the maximum supported
497          * prealloc size, we round up first, apply appropriate throttling, round
498          * down and cap the value to XFS_BMBT_MAX_EXTLEN.
499          */
500         alloc_blocks = XFS_FILEOFF_MIN(roundup_pow_of_two(XFS_MAX_BMBT_EXTLEN),
501                                        alloc_blocks);
502
503         if (unlikely(XFS_IS_REALTIME_INODE(ip)))
504                 freesp = xfs_rtx_to_rtb(mp,
505                         xfs_iomap_freesp(&mp->m_frextents,
506                                         mp->m_low_rtexts, &shift));
507         else
508                 freesp = xfs_iomap_freesp(&mp->m_fdblocks, mp->m_low_space,
509                                 &shift);
510
511         /*
512          * Check each quota to cap the prealloc size, provide a shift value to
513          * throttle with and adjust amount of available space.
514          */
515         if (xfs_quota_need_throttle(ip, XFS_DQTYPE_USER, alloc_blocks))
516                 xfs_quota_calc_throttle(ip, XFS_DQTYPE_USER, &qblocks, &qshift,
517                                         &freesp);
518         if (xfs_quota_need_throttle(ip, XFS_DQTYPE_GROUP, alloc_blocks))
519                 xfs_quota_calc_throttle(ip, XFS_DQTYPE_GROUP, &qblocks, &qshift,
520                                         &freesp);
521         if (xfs_quota_need_throttle(ip, XFS_DQTYPE_PROJ, alloc_blocks))
522                 xfs_quota_calc_throttle(ip, XFS_DQTYPE_PROJ, &qblocks, &qshift,
523                                         &freesp);
524
525         /*
526          * The final prealloc size is set to the minimum of free space available
527          * in each of the quotas and the overall filesystem.
528          *
529          * The shift throttle value is set to the maximum value as determined by
530          * the global low free space values and per-quota low free space values.
531          */
532         alloc_blocks = min(alloc_blocks, qblocks);
533         shift = max(shift, qshift);
534
535         if (shift)
536                 alloc_blocks >>= shift;
537         /*
538          * rounddown_pow_of_two() returns an undefined result if we pass in
539          * alloc_blocks = 0.
540          */
541         if (alloc_blocks)
542                 alloc_blocks = rounddown_pow_of_two(alloc_blocks);
543         if (alloc_blocks > XFS_MAX_BMBT_EXTLEN)
544                 alloc_blocks = XFS_MAX_BMBT_EXTLEN;
545
546         /*
547          * If we are still trying to allocate more space than is
548          * available, squash the prealloc hard. This can happen if we
549          * have a large file on a small filesystem and the above
550          * lowspace thresholds are smaller than XFS_BMBT_MAX_EXTLEN.
551          */
552         while (alloc_blocks && alloc_blocks >= freesp)
553                 alloc_blocks >>= 4;
554         if (alloc_blocks < mp->m_allocsize_blocks)
555                 alloc_blocks = mp->m_allocsize_blocks;
556         trace_xfs_iomap_prealloc_size(ip, alloc_blocks, shift,
557                                       mp->m_allocsize_blocks);
558         return alloc_blocks;
559 }
560
561 int
562 xfs_iomap_write_unwritten(
563         xfs_inode_t     *ip,
564         xfs_off_t       offset,
565         xfs_off_t       count,
566         bool            update_isize)
567 {
568         xfs_mount_t     *mp = ip->i_mount;
569         xfs_fileoff_t   offset_fsb;
570         xfs_filblks_t   count_fsb;
571         xfs_filblks_t   numblks_fsb;
572         int             nimaps;
573         xfs_trans_t     *tp;
574         xfs_bmbt_irec_t imap;
575         struct inode    *inode = VFS_I(ip);
576         xfs_fsize_t     i_size;
577         uint            resblks;
578         int             error;
579
580         trace_xfs_unwritten_convert(ip, offset, count);
581
582         offset_fsb = XFS_B_TO_FSBT(mp, offset);
583         count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
584         count_fsb = (xfs_filblks_t)(count_fsb - offset_fsb);
585
586         /*
587          * Reserve enough blocks in this transaction for two complete extent
588          * btree splits.  We may be converting the middle part of an unwritten
589          * extent and in this case we will insert two new extents in the btree
590          * each of which could cause a full split.
591          *
592          * This reservation amount will be used in the first call to
593          * xfs_bmbt_split() to select an AG with enough space to satisfy the
594          * rest of the operation.
595          */
596         resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
597
598         /* Attach dquots so that bmbt splits are accounted correctly. */
599         error = xfs_qm_dqattach(ip);
600         if (error)
601                 return error;
602
603         do {
604                 /*
605                  * Set up a transaction to convert the range of extents
606                  * from unwritten to real. Do allocations in a loop until
607                  * we have covered the range passed in.
608                  *
609                  * Note that we can't risk to recursing back into the filesystem
610                  * here as we might be asked to write out the same inode that we
611                  * complete here and might deadlock on the iolock.
612                  */
613                 error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, resblks,
614                                 0, true, &tp);
615                 if (error)
616                         return error;
617
618                 error = xfs_iext_count_extend(tp, ip, XFS_DATA_FORK,
619                                 XFS_IEXT_WRITE_UNWRITTEN_CNT);
620                 if (error)
621                         goto error_on_bmapi_transaction;
622
623                 /*
624                  * Modify the unwritten extent state of the buffer.
625                  */
626                 nimaps = 1;
627                 error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb,
628                                         XFS_BMAPI_CONVERT, resblks, &imap,
629                                         &nimaps);
630                 if (error)
631                         goto error_on_bmapi_transaction;
632
633                 /*
634                  * Log the updated inode size as we go.  We have to be careful
635                  * to only log it up to the actual write offset if it is
636                  * halfway into a block.
637                  */
638                 i_size = XFS_FSB_TO_B(mp, offset_fsb + count_fsb);
639                 if (i_size > offset + count)
640                         i_size = offset + count;
641                 if (update_isize && i_size > i_size_read(inode))
642                         i_size_write(inode, i_size);
643                 i_size = xfs_new_eof(ip, i_size);
644                 if (i_size) {
645                         ip->i_disk_size = i_size;
646                         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
647                 }
648
649                 error = xfs_trans_commit(tp);
650                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
651                 if (error)
652                         return error;
653
654                 if (unlikely(!xfs_valid_startblock(ip, imap.br_startblock))) {
655                         xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
656                         return xfs_alert_fsblock_zero(ip, &imap);
657                 }
658
659                 if ((numblks_fsb = imap.br_blockcount) == 0) {
660                         /*
661                          * The numblks_fsb value should always get
662                          * smaller, otherwise the loop is stuck.
663                          */
664                         ASSERT(imap.br_blockcount);
665                         break;
666                 }
667                 offset_fsb += numblks_fsb;
668                 count_fsb -= numblks_fsb;
669         } while (count_fsb > 0);
670
671         return 0;
672
673 error_on_bmapi_transaction:
674         xfs_trans_cancel(tp);
675         xfs_iunlock(ip, XFS_ILOCK_EXCL);
676         return error;
677 }
678
679 static inline bool
680 imap_needs_alloc(
681         struct inode            *inode,
682         unsigned                flags,
683         struct xfs_bmbt_irec    *imap,
684         int                     nimaps)
685 {
686         /* don't allocate blocks when just zeroing */
687         if (flags & IOMAP_ZERO)
688                 return false;
689         if (!nimaps ||
690             imap->br_startblock == HOLESTARTBLOCK ||
691             imap->br_startblock == DELAYSTARTBLOCK)
692                 return true;
693         /* we convert unwritten extents before copying the data for DAX */
694         if ((flags & IOMAP_DAX) && imap->br_state == XFS_EXT_UNWRITTEN)
695                 return true;
696         return false;
697 }
698
699 static inline bool
700 imap_needs_cow(
701         struct xfs_inode        *ip,
702         unsigned int            flags,
703         struct xfs_bmbt_irec    *imap,
704         int                     nimaps)
705 {
706         if (!xfs_is_cow_inode(ip))
707                 return false;
708
709         /* when zeroing we don't have to COW holes or unwritten extents */
710         if (flags & IOMAP_ZERO) {
711                 if (!nimaps ||
712                     imap->br_startblock == HOLESTARTBLOCK ||
713                     imap->br_state == XFS_EXT_UNWRITTEN)
714                         return false;
715         }
716
717         return true;
718 }
719
720 static int
721 xfs_ilock_for_iomap(
722         struct xfs_inode        *ip,
723         unsigned                flags,
724         unsigned                *lockmode)
725 {
726         unsigned int            mode = *lockmode;
727         bool                    is_write = flags & (IOMAP_WRITE | IOMAP_ZERO);
728
729         /*
730          * COW writes may allocate delalloc space or convert unwritten COW
731          * extents, so we need to make sure to take the lock exclusively here.
732          */
733         if (xfs_is_cow_inode(ip) && is_write)
734                 mode = XFS_ILOCK_EXCL;
735
736         /*
737          * Extents not yet cached requires exclusive access, don't block.  This
738          * is an opencoded xfs_ilock_data_map_shared() call but with
739          * non-blocking behaviour.
740          */
741         if (xfs_need_iread_extents(&ip->i_df)) {
742                 if (flags & IOMAP_NOWAIT)
743                         return -EAGAIN;
744                 mode = XFS_ILOCK_EXCL;
745         }
746
747 relock:
748         if (flags & IOMAP_NOWAIT) {
749                 if (!xfs_ilock_nowait(ip, mode))
750                         return -EAGAIN;
751         } else {
752                 xfs_ilock(ip, mode);
753         }
754
755         /*
756          * The reflink iflag could have changed since the earlier unlocked
757          * check, so if we got ILOCK_SHARED for a write and but we're now a
758          * reflink inode we have to switch to ILOCK_EXCL and relock.
759          */
760         if (mode == XFS_ILOCK_SHARED && is_write && xfs_is_cow_inode(ip)) {
761                 xfs_iunlock(ip, mode);
762                 mode = XFS_ILOCK_EXCL;
763                 goto relock;
764         }
765
766         *lockmode = mode;
767         return 0;
768 }
769
770 /*
771  * Check that the imap we are going to return to the caller spans the entire
772  * range that the caller requested for the IO.
773  */
774 static bool
775 imap_spans_range(
776         struct xfs_bmbt_irec    *imap,
777         xfs_fileoff_t           offset_fsb,
778         xfs_fileoff_t           end_fsb)
779 {
780         if (imap->br_startoff > offset_fsb)
781                 return false;
782         if (imap->br_startoff + imap->br_blockcount < end_fsb)
783                 return false;
784         return true;
785 }
786
787 static int
788 xfs_direct_write_iomap_begin(
789         struct inode            *inode,
790         loff_t                  offset,
791         loff_t                  length,
792         unsigned                flags,
793         struct iomap            *iomap,
794         struct iomap            *srcmap)
795 {
796         struct xfs_inode        *ip = XFS_I(inode);
797         struct xfs_mount        *mp = ip->i_mount;
798         struct xfs_bmbt_irec    imap, cmap;
799         xfs_fileoff_t           offset_fsb = XFS_B_TO_FSBT(mp, offset);
800         xfs_fileoff_t           end_fsb = xfs_iomap_end_fsb(mp, offset, length);
801         int                     nimaps = 1, error = 0;
802         bool                    shared = false;
803         u16                     iomap_flags = 0;
804         unsigned int            lockmode = XFS_ILOCK_SHARED;
805         u64                     seq;
806
807         ASSERT(flags & (IOMAP_WRITE | IOMAP_ZERO));
808
809         if (xfs_is_shutdown(mp))
810                 return -EIO;
811
812         /*
813          * Writes that span EOF might trigger an IO size update on completion,
814          * so consider them to be dirty for the purposes of O_DSYNC even if
815          * there is no other metadata changes pending or have been made here.
816          */
817         if (offset + length > i_size_read(inode))
818                 iomap_flags |= IOMAP_F_DIRTY;
819
820         error = xfs_ilock_for_iomap(ip, flags, &lockmode);
821         if (error)
822                 return error;
823
824         error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
825                                &nimaps, 0);
826         if (error)
827                 goto out_unlock;
828
829         if (imap_needs_cow(ip, flags, &imap, nimaps)) {
830                 error = -EAGAIN;
831                 if (flags & IOMAP_NOWAIT)
832                         goto out_unlock;
833
834                 /* may drop and re-acquire the ilock */
835                 error = xfs_reflink_allocate_cow(ip, &imap, &cmap, &shared,
836                                 &lockmode,
837                                 (flags & IOMAP_DIRECT) || IS_DAX(inode));
838                 if (error)
839                         goto out_unlock;
840                 if (shared)
841                         goto out_found_cow;
842                 end_fsb = imap.br_startoff + imap.br_blockcount;
843                 length = XFS_FSB_TO_B(mp, end_fsb) - offset;
844         }
845
846         if (imap_needs_alloc(inode, flags, &imap, nimaps))
847                 goto allocate_blocks;
848
849         /*
850          * NOWAIT and OVERWRITE I/O needs to span the entire requested I/O with
851          * a single map so that we avoid partial IO failures due to the rest of
852          * the I/O range not covered by this map triggering an EAGAIN condition
853          * when it is subsequently mapped and aborting the I/O.
854          */
855         if (flags & (IOMAP_NOWAIT | IOMAP_OVERWRITE_ONLY)) {
856                 error = -EAGAIN;
857                 if (!imap_spans_range(&imap, offset_fsb, end_fsb))
858                         goto out_unlock;
859         }
860
861         /*
862          * For overwrite only I/O, we cannot convert unwritten extents without
863          * requiring sub-block zeroing.  This can only be done under an
864          * exclusive IOLOCK, hence return -EAGAIN if this is not a written
865          * extent to tell the caller to try again.
866          */
867         if (flags & IOMAP_OVERWRITE_ONLY) {
868                 error = -EAGAIN;
869                 if (imap.br_state != XFS_EXT_NORM &&
870                     ((offset | length) & mp->m_blockmask))
871                         goto out_unlock;
872         }
873
874         seq = xfs_iomap_inode_sequence(ip, iomap_flags);
875         xfs_iunlock(ip, lockmode);
876         trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
877         return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, iomap_flags, seq);
878
879 allocate_blocks:
880         error = -EAGAIN;
881         if (flags & (IOMAP_NOWAIT | IOMAP_OVERWRITE_ONLY))
882                 goto out_unlock;
883
884         /*
885          * We cap the maximum length we map to a sane size  to keep the chunks
886          * of work done where somewhat symmetric with the work writeback does.
887          * This is a completely arbitrary number pulled out of thin air as a
888          * best guess for initial testing.
889          *
890          * Note that the values needs to be less than 32-bits wide until the
891          * lower level functions are updated.
892          */
893         length = min_t(loff_t, length, 1024 * PAGE_SIZE);
894         end_fsb = xfs_iomap_end_fsb(mp, offset, length);
895
896         if (offset + length > XFS_ISIZE(ip))
897                 end_fsb = xfs_iomap_eof_align_last_fsb(ip, end_fsb);
898         else if (nimaps && imap.br_startblock == HOLESTARTBLOCK)
899                 end_fsb = min(end_fsb, imap.br_startoff + imap.br_blockcount);
900         xfs_iunlock(ip, lockmode);
901
902         error = xfs_iomap_write_direct(ip, offset_fsb, end_fsb - offset_fsb,
903                         flags, &imap, &seq);
904         if (error)
905                 return error;
906
907         trace_xfs_iomap_alloc(ip, offset, length, XFS_DATA_FORK, &imap);
908         return xfs_bmbt_to_iomap(ip, iomap, &imap, flags,
909                                  iomap_flags | IOMAP_F_NEW, seq);
910
911 out_found_cow:
912         length = XFS_FSB_TO_B(mp, cmap.br_startoff + cmap.br_blockcount);
913         trace_xfs_iomap_found(ip, offset, length - offset, XFS_COW_FORK, &cmap);
914         if (imap.br_startblock != HOLESTARTBLOCK) {
915                 seq = xfs_iomap_inode_sequence(ip, 0);
916                 error = xfs_bmbt_to_iomap(ip, srcmap, &imap, flags, 0, seq);
917                 if (error)
918                         goto out_unlock;
919         }
920         seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
921         xfs_iunlock(ip, lockmode);
922         return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, IOMAP_F_SHARED, seq);
923
924 out_unlock:
925         if (lockmode)
926                 xfs_iunlock(ip, lockmode);
927         return error;
928 }
929
930 const struct iomap_ops xfs_direct_write_iomap_ops = {
931         .iomap_begin            = xfs_direct_write_iomap_begin,
932 };
933
934 static int
935 xfs_dax_write_iomap_end(
936         struct inode            *inode,
937         loff_t                  pos,
938         loff_t                  length,
939         ssize_t                 written,
940         unsigned                flags,
941         struct iomap            *iomap)
942 {
943         struct xfs_inode        *ip = XFS_I(inode);
944
945         if (!xfs_is_cow_inode(ip))
946                 return 0;
947
948         if (!written) {
949                 xfs_reflink_cancel_cow_range(ip, pos, length, true);
950                 return 0;
951         }
952
953         return xfs_reflink_end_cow(ip, pos, written);
954 }
955
956 const struct iomap_ops xfs_dax_write_iomap_ops = {
957         .iomap_begin    = xfs_direct_write_iomap_begin,
958         .iomap_end      = xfs_dax_write_iomap_end,
959 };
960
961 static int
962 xfs_buffered_write_iomap_begin(
963         struct inode            *inode,
964         loff_t                  offset,
965         loff_t                  count,
966         unsigned                flags,
967         struct iomap            *iomap,
968         struct iomap            *srcmap)
969 {
970         struct xfs_inode        *ip = XFS_I(inode);
971         struct xfs_mount        *mp = ip->i_mount;
972         xfs_fileoff_t           offset_fsb = XFS_B_TO_FSBT(mp, offset);
973         xfs_fileoff_t           end_fsb = xfs_iomap_end_fsb(mp, offset, count);
974         struct xfs_bmbt_irec    imap, cmap;
975         struct xfs_iext_cursor  icur, ccur;
976         xfs_fsblock_t           prealloc_blocks = 0;
977         bool                    eof = false, cow_eof = false, shared = false;
978         int                     allocfork = XFS_DATA_FORK;
979         int                     error = 0;
980         unsigned int            lockmode = XFS_ILOCK_EXCL;
981         u64                     seq;
982
983         if (xfs_is_shutdown(mp))
984                 return -EIO;
985
986         /* we can't use delayed allocations when using extent size hints */
987         if (xfs_get_extsz_hint(ip))
988                 return xfs_direct_write_iomap_begin(inode, offset, count,
989                                 flags, iomap, srcmap);
990
991         error = xfs_qm_dqattach(ip);
992         if (error)
993                 return error;
994
995         error = xfs_ilock_for_iomap(ip, flags, &lockmode);
996         if (error)
997                 return error;
998
999         if (XFS_IS_CORRUPT(mp, !xfs_ifork_has_extents(&ip->i_df)) ||
1000             XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BMAPIFORMAT)) {
1001                 xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
1002                 error = -EFSCORRUPTED;
1003                 goto out_unlock;
1004         }
1005
1006         XFS_STATS_INC(mp, xs_blk_mapw);
1007
1008         error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
1009         if (error)
1010                 goto out_unlock;
1011
1012         /*
1013          * Search the data fork first to look up our source mapping.  We
1014          * always need the data fork map, as we have to return it to the
1015          * iomap code so that the higher level write code can read data in to
1016          * perform read-modify-write cycles for unaligned writes.
1017          */
1018         eof = !xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap);
1019         if (eof)
1020                 imap.br_startoff = end_fsb; /* fake hole until the end */
1021
1022         /* We never need to allocate blocks for zeroing or unsharing a hole. */
1023         if ((flags & (IOMAP_UNSHARE | IOMAP_ZERO)) &&
1024             imap.br_startoff > offset_fsb) {
1025                 xfs_hole_to_iomap(ip, iomap, offset_fsb, imap.br_startoff);
1026                 goto out_unlock;
1027         }
1028
1029         /*
1030          * For zeroing, trim a delalloc extent that extends beyond the EOF
1031          * block.  If it starts beyond the EOF block, convert it to an
1032          * unwritten extent.
1033          */
1034         if ((flags & IOMAP_ZERO) && imap.br_startoff <= offset_fsb &&
1035             isnullstartblock(imap.br_startblock)) {
1036                 xfs_fileoff_t eof_fsb = XFS_B_TO_FSB(mp, XFS_ISIZE(ip));
1037
1038                 if (offset_fsb >= eof_fsb)
1039                         goto convert_delay;
1040                 if (end_fsb > eof_fsb) {
1041                         end_fsb = eof_fsb;
1042                         xfs_trim_extent(&imap, offset_fsb,
1043                                         end_fsb - offset_fsb);
1044                 }
1045         }
1046
1047         /*
1048          * Search the COW fork extent list even if we did not find a data fork
1049          * extent.  This serves two purposes: first this implements the
1050          * speculative preallocation using cowextsize, so that we also unshare
1051          * block adjacent to shared blocks instead of just the shared blocks
1052          * themselves.  Second the lookup in the extent list is generally faster
1053          * than going out to the shared extent tree.
1054          */
1055         if (xfs_is_cow_inode(ip)) {
1056                 if (!ip->i_cowfp) {
1057                         ASSERT(!xfs_is_reflink_inode(ip));
1058                         xfs_ifork_init_cow(ip);
1059                 }
1060                 cow_eof = !xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb,
1061                                 &ccur, &cmap);
1062                 if (!cow_eof && cmap.br_startoff <= offset_fsb) {
1063                         trace_xfs_reflink_cow_found(ip, &cmap);
1064                         goto found_cow;
1065                 }
1066         }
1067
1068         if (imap.br_startoff <= offset_fsb) {
1069                 /*
1070                  * For reflink files we may need a delalloc reservation when
1071                  * overwriting shared extents.   This includes zeroing of
1072                  * existing extents that contain data.
1073                  */
1074                 if (!xfs_is_cow_inode(ip) ||
1075                     ((flags & IOMAP_ZERO) && imap.br_state != XFS_EXT_NORM)) {
1076                         trace_xfs_iomap_found(ip, offset, count, XFS_DATA_FORK,
1077                                         &imap);
1078                         goto found_imap;
1079                 }
1080
1081                 xfs_trim_extent(&imap, offset_fsb, end_fsb - offset_fsb);
1082
1083                 /* Trim the mapping to the nearest shared extent boundary. */
1084                 error = xfs_bmap_trim_cow(ip, &imap, &shared);
1085                 if (error)
1086                         goto out_unlock;
1087
1088                 /* Not shared?  Just report the (potentially capped) extent. */
1089                 if (!shared) {
1090                         trace_xfs_iomap_found(ip, offset, count, XFS_DATA_FORK,
1091                                         &imap);
1092                         goto found_imap;
1093                 }
1094
1095                 /*
1096                  * Fork all the shared blocks from our write offset until the
1097                  * end of the extent.
1098                  */
1099                 allocfork = XFS_COW_FORK;
1100                 end_fsb = imap.br_startoff + imap.br_blockcount;
1101         } else {
1102                 /*
1103                  * We cap the maximum length we map here to MAX_WRITEBACK_PAGES
1104                  * pages to keep the chunks of work done where somewhat
1105                  * symmetric with the work writeback does.  This is a completely
1106                  * arbitrary number pulled out of thin air.
1107                  *
1108                  * Note that the values needs to be less than 32-bits wide until
1109                  * the lower level functions are updated.
1110                  */
1111                 count = min_t(loff_t, count, 1024 * PAGE_SIZE);
1112                 end_fsb = xfs_iomap_end_fsb(mp, offset, count);
1113
1114                 if (xfs_is_always_cow_inode(ip))
1115                         allocfork = XFS_COW_FORK;
1116         }
1117
1118         if (eof && offset + count > XFS_ISIZE(ip)) {
1119                 /*
1120                  * Determine the initial size of the preallocation.
1121                  * We clean up any extra preallocation when the file is closed.
1122                  */
1123                 if (xfs_has_allocsize(mp))
1124                         prealloc_blocks = mp->m_allocsize_blocks;
1125                 else if (allocfork == XFS_DATA_FORK)
1126                         prealloc_blocks = xfs_iomap_prealloc_size(ip, allocfork,
1127                                                 offset, count, &icur);
1128                 else
1129                         prealloc_blocks = xfs_iomap_prealloc_size(ip, allocfork,
1130                                                 offset, count, &ccur);
1131                 if (prealloc_blocks) {
1132                         xfs_extlen_t    align;
1133                         xfs_off_t       end_offset;
1134                         xfs_fileoff_t   p_end_fsb;
1135
1136                         end_offset = XFS_ALLOC_ALIGN(mp, offset + count - 1);
1137                         p_end_fsb = XFS_B_TO_FSBT(mp, end_offset) +
1138                                         prealloc_blocks;
1139
1140                         align = xfs_eof_alignment(ip);
1141                         if (align)
1142                                 p_end_fsb = roundup_64(p_end_fsb, align);
1143
1144                         p_end_fsb = min(p_end_fsb,
1145                                 XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
1146                         ASSERT(p_end_fsb > offset_fsb);
1147                         prealloc_blocks = p_end_fsb - end_fsb;
1148                 }
1149         }
1150
1151 retry:
1152         error = xfs_bmapi_reserve_delalloc(ip, allocfork, offset_fsb,
1153                         end_fsb - offset_fsb, prealloc_blocks,
1154                         allocfork == XFS_DATA_FORK ? &imap : &cmap,
1155                         allocfork == XFS_DATA_FORK ? &icur : &ccur,
1156                         allocfork == XFS_DATA_FORK ? eof : cow_eof);
1157         switch (error) {
1158         case 0:
1159                 break;
1160         case -ENOSPC:
1161         case -EDQUOT:
1162                 /* retry without any preallocation */
1163                 trace_xfs_delalloc_enospc(ip, offset, count);
1164                 if (prealloc_blocks) {
1165                         prealloc_blocks = 0;
1166                         goto retry;
1167                 }
1168                 fallthrough;
1169         default:
1170                 goto out_unlock;
1171         }
1172
1173         if (allocfork == XFS_COW_FORK) {
1174                 trace_xfs_iomap_alloc(ip, offset, count, allocfork, &cmap);
1175                 goto found_cow;
1176         }
1177
1178         /*
1179          * Flag newly allocated delalloc blocks with IOMAP_F_NEW so we punch
1180          * them out if the write happens to fail.
1181          */
1182         seq = xfs_iomap_inode_sequence(ip, IOMAP_F_NEW);
1183         xfs_iunlock(ip, lockmode);
1184         trace_xfs_iomap_alloc(ip, offset, count, allocfork, &imap);
1185         return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, IOMAP_F_NEW, seq);
1186
1187 found_imap:
1188         seq = xfs_iomap_inode_sequence(ip, 0);
1189         xfs_iunlock(ip, lockmode);
1190         return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0, seq);
1191
1192 convert_delay:
1193         xfs_iunlock(ip, lockmode);
1194         truncate_pagecache(inode, offset);
1195         error = xfs_bmapi_convert_delalloc(ip, XFS_DATA_FORK, offset,
1196                                            iomap, NULL);
1197         if (error)
1198                 return error;
1199
1200         trace_xfs_iomap_alloc(ip, offset, count, XFS_DATA_FORK, &imap);
1201         return 0;
1202
1203 found_cow:
1204         seq = xfs_iomap_inode_sequence(ip, 0);
1205         if (imap.br_startoff <= offset_fsb) {
1206                 error = xfs_bmbt_to_iomap(ip, srcmap, &imap, flags, 0, seq);
1207                 if (error)
1208                         goto out_unlock;
1209                 seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
1210                 xfs_iunlock(ip, lockmode);
1211                 return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
1212                                          IOMAP_F_SHARED, seq);
1213         }
1214
1215         xfs_trim_extent(&cmap, offset_fsb, imap.br_startoff - offset_fsb);
1216         xfs_iunlock(ip, lockmode);
1217         return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, 0, seq);
1218
1219 out_unlock:
1220         xfs_iunlock(ip, lockmode);
1221         return error;
1222 }
1223
1224 static int
1225 xfs_buffered_write_delalloc_punch(
1226         struct inode            *inode,
1227         loff_t                  offset,
1228         loff_t                  length)
1229 {
1230         xfs_bmap_punch_delalloc_range(XFS_I(inode), offset, offset + length);
1231         return 0;
1232 }
1233
1234 static int
1235 xfs_buffered_write_iomap_end(
1236         struct inode            *inode,
1237         loff_t                  offset,
1238         loff_t                  length,
1239         ssize_t                 written,
1240         unsigned                flags,
1241         struct iomap            *iomap)
1242 {
1243
1244         struct xfs_mount        *mp = XFS_M(inode->i_sb);
1245         int                     error;
1246
1247         error = iomap_file_buffered_write_punch_delalloc(inode, iomap, offset,
1248                         length, written, &xfs_buffered_write_delalloc_punch);
1249         if (error && !xfs_is_shutdown(mp)) {
1250                 xfs_alert(mp, "%s: unable to clean up ino 0x%llx",
1251                         __func__, XFS_I(inode)->i_ino);
1252                 return error;
1253         }
1254         return 0;
1255 }
1256
1257 const struct iomap_ops xfs_buffered_write_iomap_ops = {
1258         .iomap_begin            = xfs_buffered_write_iomap_begin,
1259         .iomap_end              = xfs_buffered_write_iomap_end,
1260 };
1261
1262 /*
1263  * iomap_page_mkwrite() will never fail in a way that requires delalloc extents
1264  * that it allocated to be revoked. Hence we do not need an .iomap_end method
1265  * for this operation.
1266  */
1267 const struct iomap_ops xfs_page_mkwrite_iomap_ops = {
1268         .iomap_begin            = xfs_buffered_write_iomap_begin,
1269 };
1270
1271 static int
1272 xfs_read_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         struct xfs_bmbt_irec    imap;
1283         xfs_fileoff_t           offset_fsb = XFS_B_TO_FSBT(mp, offset);
1284         xfs_fileoff_t           end_fsb = xfs_iomap_end_fsb(mp, offset, length);
1285         int                     nimaps = 1, error = 0;
1286         bool                    shared = false;
1287         unsigned int            lockmode = XFS_ILOCK_SHARED;
1288         u64                     seq;
1289
1290         ASSERT(!(flags & (IOMAP_WRITE | IOMAP_ZERO)));
1291
1292         if (xfs_is_shutdown(mp))
1293                 return -EIO;
1294
1295         error = xfs_ilock_for_iomap(ip, flags, &lockmode);
1296         if (error)
1297                 return error;
1298         error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
1299                                &nimaps, 0);
1300         if (!error && ((flags & IOMAP_REPORT) || IS_DAX(inode)))
1301                 error = xfs_reflink_trim_around_shared(ip, &imap, &shared);
1302         seq = xfs_iomap_inode_sequence(ip, shared ? IOMAP_F_SHARED : 0);
1303         xfs_iunlock(ip, lockmode);
1304
1305         if (error)
1306                 return error;
1307         trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
1308         return xfs_bmbt_to_iomap(ip, iomap, &imap, flags,
1309                                  shared ? IOMAP_F_SHARED : 0, seq);
1310 }
1311
1312 const struct iomap_ops xfs_read_iomap_ops = {
1313         .iomap_begin            = xfs_read_iomap_begin,
1314 };
1315
1316 static int
1317 xfs_seek_iomap_begin(
1318         struct inode            *inode,
1319         loff_t                  offset,
1320         loff_t                  length,
1321         unsigned                flags,
1322         struct iomap            *iomap,
1323         struct iomap            *srcmap)
1324 {
1325         struct xfs_inode        *ip = XFS_I(inode);
1326         struct xfs_mount        *mp = ip->i_mount;
1327         xfs_fileoff_t           offset_fsb = XFS_B_TO_FSBT(mp, offset);
1328         xfs_fileoff_t           end_fsb = XFS_B_TO_FSB(mp, offset + length);
1329         xfs_fileoff_t           cow_fsb = NULLFILEOFF, data_fsb = NULLFILEOFF;
1330         struct xfs_iext_cursor  icur;
1331         struct xfs_bmbt_irec    imap, cmap;
1332         int                     error = 0;
1333         unsigned                lockmode;
1334         u64                     seq;
1335
1336         if (xfs_is_shutdown(mp))
1337                 return -EIO;
1338
1339         lockmode = xfs_ilock_data_map_shared(ip);
1340         error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
1341         if (error)
1342                 goto out_unlock;
1343
1344         if (xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap)) {
1345                 /*
1346                  * If we found a data extent we are done.
1347                  */
1348                 if (imap.br_startoff <= offset_fsb)
1349                         goto done;
1350                 data_fsb = imap.br_startoff;
1351         } else {
1352                 /*
1353                  * Fake a hole until the end of the file.
1354                  */
1355                 data_fsb = xfs_iomap_end_fsb(mp, offset, length);
1356         }
1357
1358         /*
1359          * If a COW fork extent covers the hole, report it - capped to the next
1360          * data fork extent:
1361          */
1362         if (xfs_inode_has_cow_data(ip) &&
1363             xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &cmap))
1364                 cow_fsb = cmap.br_startoff;
1365         if (cow_fsb != NULLFILEOFF && cow_fsb <= offset_fsb) {
1366                 if (data_fsb < cow_fsb + cmap.br_blockcount)
1367                         end_fsb = min(end_fsb, data_fsb);
1368                 xfs_trim_extent(&cmap, offset_fsb, end_fsb - offset_fsb);
1369                 seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
1370                 error = xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
1371                                 IOMAP_F_SHARED, seq);
1372                 /*
1373                  * This is a COW extent, so we must probe the page cache
1374                  * because there could be dirty page cache being backed
1375                  * by this extent.
1376                  */
1377                 iomap->type = IOMAP_UNWRITTEN;
1378                 goto out_unlock;
1379         }
1380
1381         /*
1382          * Else report a hole, capped to the next found data or COW extent.
1383          */
1384         if (cow_fsb != NULLFILEOFF && cow_fsb < data_fsb)
1385                 imap.br_blockcount = cow_fsb - offset_fsb;
1386         else
1387                 imap.br_blockcount = data_fsb - offset_fsb;
1388         imap.br_startoff = offset_fsb;
1389         imap.br_startblock = HOLESTARTBLOCK;
1390         imap.br_state = XFS_EXT_NORM;
1391 done:
1392         seq = xfs_iomap_inode_sequence(ip, 0);
1393         xfs_trim_extent(&imap, offset_fsb, end_fsb - offset_fsb);
1394         error = xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0, seq);
1395 out_unlock:
1396         xfs_iunlock(ip, lockmode);
1397         return error;
1398 }
1399
1400 const struct iomap_ops xfs_seek_iomap_ops = {
1401         .iomap_begin            = xfs_seek_iomap_begin,
1402 };
1403
1404 static int
1405 xfs_xattr_iomap_begin(
1406         struct inode            *inode,
1407         loff_t                  offset,
1408         loff_t                  length,
1409         unsigned                flags,
1410         struct iomap            *iomap,
1411         struct iomap            *srcmap)
1412 {
1413         struct xfs_inode        *ip = XFS_I(inode);
1414         struct xfs_mount        *mp = ip->i_mount;
1415         xfs_fileoff_t           offset_fsb = XFS_B_TO_FSBT(mp, offset);
1416         xfs_fileoff_t           end_fsb = XFS_B_TO_FSB(mp, offset + length);
1417         struct xfs_bmbt_irec    imap;
1418         int                     nimaps = 1, error = 0;
1419         unsigned                lockmode;
1420         int                     seq;
1421
1422         if (xfs_is_shutdown(mp))
1423                 return -EIO;
1424
1425         lockmode = xfs_ilock_attr_map_shared(ip);
1426
1427         /* if there are no attribute fork or extents, return ENOENT */
1428         if (!xfs_inode_has_attr_fork(ip) || !ip->i_af.if_nextents) {
1429                 error = -ENOENT;
1430                 goto out_unlock;
1431         }
1432
1433         ASSERT(ip->i_af.if_format != XFS_DINODE_FMT_LOCAL);
1434         error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
1435                                &nimaps, XFS_BMAPI_ATTRFORK);
1436 out_unlock:
1437
1438         seq = xfs_iomap_inode_sequence(ip, IOMAP_F_XATTR);
1439         xfs_iunlock(ip, lockmode);
1440
1441         if (error)
1442                 return error;
1443         ASSERT(nimaps);
1444         return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, IOMAP_F_XATTR, seq);
1445 }
1446
1447 const struct iomap_ops xfs_xattr_iomap_ops = {
1448         .iomap_begin            = xfs_xattr_iomap_begin,
1449 };
1450
1451 int
1452 xfs_zero_range(
1453         struct xfs_inode        *ip,
1454         loff_t                  pos,
1455         loff_t                  len,
1456         bool                    *did_zero)
1457 {
1458         struct inode            *inode = VFS_I(ip);
1459
1460         if (IS_DAX(inode))
1461                 return dax_zero_range(inode, pos, len, did_zero,
1462                                       &xfs_dax_write_iomap_ops);
1463         return iomap_zero_range(inode, pos, len, did_zero,
1464                                 &xfs_buffered_write_iomap_ops);
1465 }
1466
1467 int
1468 xfs_truncate_page(
1469         struct xfs_inode        *ip,
1470         loff_t                  pos,
1471         bool                    *did_zero)
1472 {
1473         struct inode            *inode = VFS_I(ip);
1474
1475         if (IS_DAX(inode))
1476                 return dax_truncate_page(inode, pos, did_zero,
1477                                         &xfs_dax_write_iomap_ops);
1478         return iomap_truncate_page(inode, pos, did_zero,
1479                                    &xfs_buffered_write_iomap_ops);
1480 }
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