1 // SPDX-License-Identifier: GPL-2.0+
3 * Copyright (C) 2016 Oracle. All Rights Reserved.
4 * Author: Darrick J. Wong <darrick.wong@oracle.com>
8 #include "xfs_shared.h"
9 #include "xfs_format.h"
10 #include "xfs_log_format.h"
11 #include "xfs_trans_resv.h"
12 #include "xfs_mount.h"
13 #include "xfs_defer.h"
14 #include "xfs_inode.h"
15 #include "xfs_trans.h"
17 #include "xfs_bmap_util.h"
18 #include "xfs_trace.h"
19 #include "xfs_icache.h"
20 #include "xfs_btree.h"
21 #include "xfs_refcount_btree.h"
22 #include "xfs_refcount.h"
23 #include "xfs_bmap_btree.h"
24 #include "xfs_trans_space.h"
26 #include "xfs_alloc.h"
27 #include "xfs_quota.h"
28 #include "xfs_reflink.h"
29 #include "xfs_iomap.h"
31 #include "xfs_ag_resv.h"
34 * Copy on Write of Shared Blocks
36 * XFS must preserve "the usual" file semantics even when two files share
37 * the same physical blocks. This means that a write to one file must not
38 * alter the blocks in a different file; the way that we'll do that is
39 * through the use of a copy-on-write mechanism. At a high level, that
40 * means that when we want to write to a shared block, we allocate a new
41 * block, write the data to the new block, and if that succeeds we map the
42 * new block into the file.
44 * XFS provides a "delayed allocation" mechanism that defers the allocation
45 * of disk blocks to dirty-but-not-yet-mapped file blocks as long as
46 * possible. This reduces fragmentation by enabling the filesystem to ask
47 * for bigger chunks less often, which is exactly what we want for CoW.
49 * The delalloc mechanism begins when the kernel wants to make a block
50 * writable (write_begin or page_mkwrite). If the offset is not mapped, we
51 * create a delalloc mapping, which is a regular in-core extent, but without
52 * a real startblock. (For delalloc mappings, the startblock encodes both
53 * a flag that this is a delalloc mapping, and a worst-case estimate of how
54 * many blocks might be required to put the mapping into the BMBT.) delalloc
55 * mappings are a reservation against the free space in the filesystem;
56 * adjacent mappings can also be combined into fewer larger mappings.
58 * As an optimization, the CoW extent size hint (cowextsz) creates
59 * outsized aligned delalloc reservations in the hope of landing out of
60 * order nearby CoW writes in a single extent on disk, thereby reducing
61 * fragmentation and improving future performance.
63 * D: --RRRRRRSSSRRRRRRRR--- (data fork)
64 * C: ------DDDDDDD--------- (CoW fork)
66 * When dirty pages are being written out (typically in writepage), the
67 * delalloc reservations are converted into unwritten mappings by
68 * allocating blocks and replacing the delalloc mapping with real ones.
69 * A delalloc mapping can be replaced by several unwritten ones if the
70 * free space is fragmented.
72 * D: --RRRRRRSSSRRRRRRRR---
73 * C: ------UUUUUUU---------
75 * We want to adapt the delalloc mechanism for copy-on-write, since the
76 * write paths are similar. The first two steps (creating the reservation
77 * and allocating the blocks) are exactly the same as delalloc except that
78 * the mappings must be stored in a separate CoW fork because we do not want
79 * to disturb the mapping in the data fork until we're sure that the write
80 * succeeded. IO completion in this case is the process of removing the old
81 * mapping from the data fork and moving the new mapping from the CoW fork to
82 * the data fork. This will be discussed shortly.
84 * For now, unaligned directio writes will be bounced back to the page cache.
85 * Block-aligned directio writes will use the same mechanism as buffered
88 * Just prior to submitting the actual disk write requests, we convert
89 * the extents representing the range of the file actually being written
90 * (as opposed to extra pieces created for the cowextsize hint) to real
91 * extents. This will become important in the next step:
93 * D: --RRRRRRSSSRRRRRRRR---
94 * C: ------UUrrUUU---------
96 * CoW remapping must be done after the data block write completes,
97 * because we don't want to destroy the old data fork map until we're sure
98 * the new block has been written. Since the new mappings are kept in a
99 * separate fork, we can simply iterate these mappings to find the ones
100 * that cover the file blocks that we just CoW'd. For each extent, simply
101 * unmap the corresponding range in the data fork, map the new range into
102 * the data fork, and remove the extent from the CoW fork. Because of
103 * the presence of the cowextsize hint, however, we must be careful
104 * only to remap the blocks that we've actually written out -- we must
105 * never remap delalloc reservations nor CoW staging blocks that have
106 * yet to be written. This corresponds exactly to the real extents in
109 * D: --RRRRRRrrSRRRRRRRR---
110 * C: ------UU--UUU---------
112 * Since the remapping operation can be applied to an arbitrary file
113 * range, we record the need for the remap step as a flag in the ioend
114 * instead of declaring a new IO type. This is required for direct io
115 * because we only have ioend for the whole dio, and we have to be able to
116 * remember the presence of unwritten blocks and CoW blocks with a single
117 * ioend structure. Better yet, the more ground we can cover with one
122 * Given an AG extent, find the lowest-numbered run of shared blocks
123 * within that range and return the range in fbno/flen. If
124 * find_end_of_shared is true, return the longest contiguous extent of
125 * shared blocks. If there are no shared extents, fbno and flen will
126 * be set to NULLAGBLOCK and 0, respectively.
129 xfs_reflink_find_shared(
130 struct xfs_perag *pag,
131 struct xfs_trans *tp,
136 bool find_end_of_shared)
138 struct xfs_buf *agbp;
139 struct xfs_btree_cur *cur;
142 error = xfs_alloc_read_agf(pag, tp, 0, &agbp);
146 cur = xfs_refcountbt_init_cursor(pag->pag_mount, tp, agbp, pag);
148 error = xfs_refcount_find_shared(cur, agbno, aglen, fbno, flen,
151 xfs_btree_del_cursor(cur, error);
153 xfs_trans_brelse(tp, agbp);
158 * Trim the mapping to the next block where there's a change in the
159 * shared/unshared status. More specifically, this means that we
160 * find the lowest-numbered extent of shared blocks that coincides with
161 * the given block mapping. If the shared extent overlaps the start of
162 * the mapping, trim the mapping to the end of the shared extent. If
163 * the shared region intersects the mapping, trim the mapping to the
164 * start of the shared extent. If there are no shared regions that
165 * overlap, just return the original extent.
168 xfs_reflink_trim_around_shared(
169 struct xfs_inode *ip,
170 struct xfs_bmbt_irec *irec,
173 struct xfs_mount *mp = ip->i_mount;
174 struct xfs_perag *pag;
181 /* Holes, unwritten, and delalloc extents cannot be shared */
182 if (!xfs_is_cow_inode(ip) || !xfs_bmap_is_written_extent(irec)) {
187 trace_xfs_reflink_trim_around_shared(ip, irec);
189 pag = xfs_perag_get(mp, XFS_FSB_TO_AGNO(mp, irec->br_startblock));
190 agbno = XFS_FSB_TO_AGBNO(mp, irec->br_startblock);
191 aglen = irec->br_blockcount;
193 error = xfs_reflink_find_shared(pag, NULL, agbno, aglen, &fbno, &flen,
200 if (fbno == NULLAGBLOCK) {
201 /* No shared blocks at all. */
207 * The start of this extent is shared. Truncate the
208 * mapping at the end of the shared region so that a
209 * subsequent iteration starts at the start of the
212 irec->br_blockcount = flen;
218 * There's a shared extent midway through this extent.
219 * Truncate the mapping at the start of the shared
220 * extent so that a subsequent iteration starts at the
221 * start of the shared region.
223 irec->br_blockcount = fbno - agbno;
229 struct xfs_inode *ip,
230 struct xfs_bmbt_irec *imap,
233 /* We can't update any real extents in always COW mode. */
234 if (xfs_is_always_cow_inode(ip) &&
235 !isnullstartblock(imap->br_startblock)) {
240 /* Trim the mapping to the nearest shared extent boundary. */
241 return xfs_reflink_trim_around_shared(ip, imap, shared);
245 xfs_reflink_convert_cow_locked(
246 struct xfs_inode *ip,
247 xfs_fileoff_t offset_fsb,
248 xfs_filblks_t count_fsb)
250 struct xfs_iext_cursor icur;
251 struct xfs_bmbt_irec got;
252 struct xfs_btree_cur *dummy_cur = NULL;
256 if (!xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &got))
260 if (got.br_startoff >= offset_fsb + count_fsb)
262 if (got.br_state == XFS_EXT_NORM)
264 if (WARN_ON_ONCE(isnullstartblock(got.br_startblock)))
267 xfs_trim_extent(&got, offset_fsb, count_fsb);
268 if (!got.br_blockcount)
271 got.br_state = XFS_EXT_NORM;
272 error = xfs_bmap_add_extent_unwritten_real(NULL, ip,
273 XFS_COW_FORK, &icur, &dummy_cur, &got,
277 } while (xfs_iext_next_extent(ip->i_cowfp, &icur, &got));
282 /* Convert all of the unwritten CoW extents in a file's range to real ones. */
284 xfs_reflink_convert_cow(
285 struct xfs_inode *ip,
289 struct xfs_mount *mp = ip->i_mount;
290 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
291 xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + count);
292 xfs_filblks_t count_fsb = end_fsb - offset_fsb;
297 xfs_ilock(ip, XFS_ILOCK_EXCL);
298 error = xfs_reflink_convert_cow_locked(ip, offset_fsb, count_fsb);
299 xfs_iunlock(ip, XFS_ILOCK_EXCL);
304 * Find the extent that maps the given range in the COW fork. Even if the extent
305 * is not shared we might have a preallocation for it in the COW fork. If so we
306 * use it that rather than trigger a new allocation.
309 xfs_find_trim_cow_extent(
310 struct xfs_inode *ip,
311 struct xfs_bmbt_irec *imap,
312 struct xfs_bmbt_irec *cmap,
316 xfs_fileoff_t offset_fsb = imap->br_startoff;
317 xfs_filblks_t count_fsb = imap->br_blockcount;
318 struct xfs_iext_cursor icur;
323 * If we don't find an overlapping extent, trim the range we need to
324 * allocate to fit the hole we found.
326 if (!xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, cmap))
327 cmap->br_startoff = offset_fsb + count_fsb;
328 if (cmap->br_startoff > offset_fsb) {
329 xfs_trim_extent(imap, imap->br_startoff,
330 cmap->br_startoff - imap->br_startoff);
331 return xfs_bmap_trim_cow(ip, imap, shared);
335 if (isnullstartblock(cmap->br_startblock)) {
336 xfs_trim_extent(imap, cmap->br_startoff, cmap->br_blockcount);
340 /* real extent found - no need to allocate */
341 xfs_trim_extent(cmap, offset_fsb, count_fsb);
347 xfs_reflink_convert_unwritten(
348 struct xfs_inode *ip,
349 struct xfs_bmbt_irec *imap,
350 struct xfs_bmbt_irec *cmap,
353 xfs_fileoff_t offset_fsb = imap->br_startoff;
354 xfs_filblks_t count_fsb = imap->br_blockcount;
358 * cmap might larger than imap due to cowextsize hint.
360 xfs_trim_extent(cmap, offset_fsb, count_fsb);
363 * COW fork extents are supposed to remain unwritten until we're ready
364 * to initiate a disk write. For direct I/O we are going to write the
365 * data and need the conversion, but for buffered writes we're done.
367 if (!convert_now || cmap->br_state == XFS_EXT_NORM)
370 trace_xfs_reflink_convert_cow(ip, cmap);
372 error = xfs_reflink_convert_cow_locked(ip, offset_fsb, count_fsb);
374 cmap->br_state = XFS_EXT_NORM;
380 xfs_reflink_fill_cow_hole(
381 struct xfs_inode *ip,
382 struct xfs_bmbt_irec *imap,
383 struct xfs_bmbt_irec *cmap,
388 struct xfs_mount *mp = ip->i_mount;
389 struct xfs_trans *tp;
390 xfs_filblks_t resaligned;
391 xfs_extlen_t resblks;
396 resaligned = xfs_aligned_fsb_count(imap->br_startoff,
397 imap->br_blockcount, xfs_get_cowextsz_hint(ip));
398 resblks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
400 xfs_iunlock(ip, *lockmode);
403 error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, resblks, 0,
408 *lockmode = XFS_ILOCK_EXCL;
410 error = xfs_find_trim_cow_extent(ip, imap, cmap, shared, &found);
411 if (error || !*shared)
412 goto out_trans_cancel;
415 xfs_trans_cancel(tp);
419 /* Allocate the entire reservation as unwritten blocks. */
421 error = xfs_bmapi_write(tp, ip, imap->br_startoff, imap->br_blockcount,
422 XFS_BMAPI_COWFORK | XFS_BMAPI_PREALLOC, 0, cmap,
425 goto out_trans_cancel;
427 xfs_inode_set_cowblocks_tag(ip);
428 error = xfs_trans_commit(tp);
433 * Allocation succeeded but the requested range was not even partially
434 * satisfied? Bail out!
440 return xfs_reflink_convert_unwritten(ip, imap, cmap, convert_now);
443 xfs_trans_cancel(tp);
448 xfs_reflink_fill_delalloc(
449 struct xfs_inode *ip,
450 struct xfs_bmbt_irec *imap,
451 struct xfs_bmbt_irec *cmap,
456 struct xfs_mount *mp = ip->i_mount;
457 struct xfs_trans *tp;
463 xfs_iunlock(ip, *lockmode);
466 error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, 0, 0,
471 *lockmode = XFS_ILOCK_EXCL;
473 error = xfs_find_trim_cow_extent(ip, imap, cmap, shared,
475 if (error || !*shared)
476 goto out_trans_cancel;
479 xfs_trans_cancel(tp);
483 ASSERT(isnullstartblock(cmap->br_startblock) ||
484 cmap->br_startblock == DELAYSTARTBLOCK);
487 * Replace delalloc reservation with an unwritten extent.
490 error = xfs_bmapi_write(tp, ip, cmap->br_startoff,
492 XFS_BMAPI_COWFORK | XFS_BMAPI_PREALLOC, 0,
495 goto out_trans_cancel;
497 xfs_inode_set_cowblocks_tag(ip);
498 error = xfs_trans_commit(tp);
503 * Allocation succeeded but the requested range was not even
504 * partially satisfied? Bail out!
508 } while (cmap->br_startoff + cmap->br_blockcount <= imap->br_startoff);
510 return xfs_reflink_convert_unwritten(ip, imap, cmap, convert_now);
513 xfs_trans_cancel(tp);
517 /* Allocate all CoW reservations covering a range of blocks in a file. */
519 xfs_reflink_allocate_cow(
520 struct xfs_inode *ip,
521 struct xfs_bmbt_irec *imap,
522 struct xfs_bmbt_irec *cmap,
530 ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
532 ASSERT(!xfs_is_reflink_inode(ip));
533 xfs_ifork_init_cow(ip);
536 error = xfs_find_trim_cow_extent(ip, imap, cmap, shared, &found);
537 if (error || !*shared)
540 /* CoW fork has a real extent */
542 return xfs_reflink_convert_unwritten(ip, imap, cmap,
546 * CoW fork does not have an extent and data extent is shared.
547 * Allocate a real extent in the CoW fork.
549 if (cmap->br_startoff > imap->br_startoff)
550 return xfs_reflink_fill_cow_hole(ip, imap, cmap, shared,
551 lockmode, convert_now);
554 * CoW fork has a delalloc reservation. Replace it with a real extent.
555 * There may or may not be a data fork mapping.
557 if (isnullstartblock(cmap->br_startblock) ||
558 cmap->br_startblock == DELAYSTARTBLOCK)
559 return xfs_reflink_fill_delalloc(ip, imap, cmap, shared,
560 lockmode, convert_now);
562 /* Shouldn't get here. */
564 return -EFSCORRUPTED;
568 * Cancel CoW reservations for some block range of an inode.
570 * If cancel_real is true this function cancels all COW fork extents for the
571 * inode; if cancel_real is false, real extents are not cleared.
573 * Caller must have already joined the inode to the current transaction. The
574 * inode will be joined to the transaction returned to the caller.
577 xfs_reflink_cancel_cow_blocks(
578 struct xfs_inode *ip,
579 struct xfs_trans **tpp,
580 xfs_fileoff_t offset_fsb,
581 xfs_fileoff_t end_fsb,
584 struct xfs_ifork *ifp = xfs_ifork_ptr(ip, XFS_COW_FORK);
585 struct xfs_bmbt_irec got, del;
586 struct xfs_iext_cursor icur;
589 if (!xfs_inode_has_cow_data(ip))
591 if (!xfs_iext_lookup_extent_before(ip, ifp, &end_fsb, &icur, &got))
594 /* Walk backwards until we're out of the I/O range... */
595 while (got.br_startoff + got.br_blockcount > offset_fsb) {
597 xfs_trim_extent(&del, offset_fsb, end_fsb - offset_fsb);
599 /* Extent delete may have bumped ext forward */
600 if (!del.br_blockcount) {
601 xfs_iext_prev(ifp, &icur);
605 trace_xfs_reflink_cancel_cow(ip, &del);
607 if (isnullstartblock(del.br_startblock)) {
608 error = xfs_bmap_del_extent_delay(ip, XFS_COW_FORK,
612 } else if (del.br_state == XFS_EXT_UNWRITTEN || cancel_real) {
613 ASSERT((*tpp)->t_highest_agno == NULLAGNUMBER);
615 /* Free the CoW orphan record. */
616 xfs_refcount_free_cow_extent(*tpp, del.br_startblock,
619 error = xfs_free_extent_later(*tpp, del.br_startblock,
620 del.br_blockcount, NULL,
625 /* Roll the transaction */
626 error = xfs_defer_finish(tpp);
630 /* Remove the mapping from the CoW fork. */
631 xfs_bmap_del_extent_cow(ip, &icur, &got, &del);
633 /* Remove the quota reservation */
634 error = xfs_quota_unreserve_blkres(ip,
639 /* Didn't do anything, push cursor back. */
640 xfs_iext_prev(ifp, &icur);
643 if (!xfs_iext_get_extent(ifp, &icur, &got))
647 /* clear tag if cow fork is emptied */
649 xfs_inode_clear_cowblocks_tag(ip);
654 * Cancel CoW reservations for some byte range of an inode.
656 * If cancel_real is true this function cancels all COW fork extents for the
657 * inode; if cancel_real is false, real extents are not cleared.
660 xfs_reflink_cancel_cow_range(
661 struct xfs_inode *ip,
666 struct xfs_trans *tp;
667 xfs_fileoff_t offset_fsb;
668 xfs_fileoff_t end_fsb;
671 trace_xfs_reflink_cancel_cow_range(ip, offset, count);
674 offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
675 if (count == NULLFILEOFF)
676 end_fsb = NULLFILEOFF;
678 end_fsb = XFS_B_TO_FSB(ip->i_mount, offset + count);
680 /* Start a rolling transaction to remove the mappings */
681 error = xfs_trans_alloc(ip->i_mount, &M_RES(ip->i_mount)->tr_write,
686 xfs_ilock(ip, XFS_ILOCK_EXCL);
687 xfs_trans_ijoin(tp, ip, 0);
689 /* Scrape out the old CoW reservations */
690 error = xfs_reflink_cancel_cow_blocks(ip, &tp, offset_fsb, end_fsb,
695 error = xfs_trans_commit(tp);
697 xfs_iunlock(ip, XFS_ILOCK_EXCL);
701 xfs_trans_cancel(tp);
702 xfs_iunlock(ip, XFS_ILOCK_EXCL);
704 trace_xfs_reflink_cancel_cow_range_error(ip, error, _RET_IP_);
709 * Remap part of the CoW fork into the data fork.
711 * We aim to remap the range starting at @offset_fsb and ending at @end_fsb
712 * into the data fork; this function will remap what it can (at the end of the
713 * range) and update @end_fsb appropriately. Each remap gets its own
714 * transaction because we can end up merging and splitting bmbt blocks for
715 * every remap operation and we'd like to keep the block reservation
716 * requirements as low as possible.
719 xfs_reflink_end_cow_extent(
720 struct xfs_inode *ip,
721 xfs_fileoff_t *offset_fsb,
722 xfs_fileoff_t end_fsb)
724 struct xfs_iext_cursor icur;
725 struct xfs_bmbt_irec got, del, data;
726 struct xfs_mount *mp = ip->i_mount;
727 struct xfs_trans *tp;
728 struct xfs_ifork *ifp = xfs_ifork_ptr(ip, XFS_COW_FORK);
729 unsigned int resblks;
733 /* No COW extents? That's easy! */
734 if (ifp->if_bytes == 0) {
735 *offset_fsb = end_fsb;
739 resblks = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
740 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0,
741 XFS_TRANS_RESERVE, &tp);
746 * Lock the inode. We have to ijoin without automatic unlock because
747 * the lead transaction is the refcountbt record deletion; the data
748 * fork update follows as a deferred log item.
750 xfs_ilock(ip, XFS_ILOCK_EXCL);
751 xfs_trans_ijoin(tp, ip, 0);
753 error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
754 XFS_IEXT_REFLINK_END_COW_CNT);
756 error = xfs_iext_count_upgrade(tp, ip,
757 XFS_IEXT_REFLINK_END_COW_CNT);
762 * In case of racing, overlapping AIO writes no COW extents might be
763 * left by the time I/O completes for the loser of the race. In that
766 if (!xfs_iext_lookup_extent(ip, ifp, *offset_fsb, &icur, &got) ||
767 got.br_startoff >= end_fsb) {
768 *offset_fsb = end_fsb;
773 * Only remap real extents that contain data. With AIO, speculative
774 * preallocations can leak into the range we are called upon, and we
775 * need to skip them. Preserve @got for the eventual CoW fork
776 * deletion; from now on @del represents the mapping that we're
777 * actually remapping.
779 while (!xfs_bmap_is_written_extent(&got)) {
780 if (!xfs_iext_next_extent(ifp, &icur, &got) ||
781 got.br_startoff >= end_fsb) {
782 *offset_fsb = end_fsb;
788 /* Grab the corresponding mapping in the data fork. */
790 error = xfs_bmapi_read(ip, del.br_startoff, del.br_blockcount, &data,
795 /* We can only remap the smaller of the two extent sizes. */
796 data.br_blockcount = min(data.br_blockcount, del.br_blockcount);
797 del.br_blockcount = data.br_blockcount;
799 trace_xfs_reflink_cow_remap_from(ip, &del);
800 trace_xfs_reflink_cow_remap_to(ip, &data);
802 if (xfs_bmap_is_real_extent(&data)) {
804 * If the extent we're remapping is backed by storage (written
805 * or not), unmap the extent and drop its refcount.
807 xfs_bmap_unmap_extent(tp, ip, &data);
808 xfs_refcount_decrease_extent(tp, &data);
809 xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT,
810 -data.br_blockcount);
811 } else if (data.br_startblock == DELAYSTARTBLOCK) {
815 * If the extent we're remapping is a delalloc reservation,
816 * we can use the regular bunmapi function to release the
817 * incore state. Dropping the delalloc reservation takes care
818 * of the quota reservation for us.
820 error = xfs_bunmapi(NULL, ip, data.br_startoff,
821 data.br_blockcount, 0, 1, &done);
827 /* Free the CoW orphan record. */
828 xfs_refcount_free_cow_extent(tp, del.br_startblock, del.br_blockcount);
830 /* Map the new blocks into the data fork. */
831 xfs_bmap_map_extent(tp, ip, &del);
833 /* Charge this new data fork mapping to the on-disk quota. */
834 xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_DELBCOUNT,
835 (long)del.br_blockcount);
837 /* Remove the mapping from the CoW fork. */
838 xfs_bmap_del_extent_cow(ip, &icur, &got, &del);
840 error = xfs_trans_commit(tp);
841 xfs_iunlock(ip, XFS_ILOCK_EXCL);
845 /* Update the caller about how much progress we made. */
846 *offset_fsb = del.br_startoff + del.br_blockcount;
850 xfs_trans_cancel(tp);
851 xfs_iunlock(ip, XFS_ILOCK_EXCL);
856 * Remap parts of a file's data fork after a successful CoW.
860 struct xfs_inode *ip,
864 xfs_fileoff_t offset_fsb;
865 xfs_fileoff_t end_fsb;
868 trace_xfs_reflink_end_cow(ip, offset, count);
870 offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
871 end_fsb = XFS_B_TO_FSB(ip->i_mount, offset + count);
874 * Walk forwards until we've remapped the I/O range. The loop function
875 * repeatedly cycles the ILOCK to allocate one transaction per remapped
878 * If we're being called by writeback then the pages will still
879 * have PageWriteback set, which prevents races with reflink remapping
880 * and truncate. Reflink remapping prevents races with writeback by
881 * taking the iolock and mmaplock before flushing the pages and
882 * remapping, which means there won't be any further writeback or page
883 * cache dirtying until the reflink completes.
885 * We should never have two threads issuing writeback for the same file
886 * region. There are also have post-eof checks in the writeback
887 * preparation code so that we don't bother writing out pages that are
888 * about to be truncated.
890 * If we're being called as part of directio write completion, the dio
891 * count is still elevated, which reflink and truncate will wait for.
892 * Reflink remapping takes the iolock and mmaplock and waits for
893 * pending dio to finish, which should prevent any directio until the
894 * remap completes. Multiple concurrent directio writes to the same
895 * region are handled by end_cow processing only occurring for the
896 * threads which succeed; the outcome of multiple overlapping direct
897 * writes is not well defined anyway.
899 * It's possible that a buffered write and a direct write could collide
900 * here (the buffered write stumbles in after the dio flushes and
901 * invalidates the page cache and immediately queues writeback), but we
902 * have never supported this 100%. If either disk write succeeds the
903 * blocks will be remapped.
905 while (end_fsb > offset_fsb && !error)
906 error = xfs_reflink_end_cow_extent(ip, &offset_fsb, end_fsb);
909 trace_xfs_reflink_end_cow_error(ip, error, _RET_IP_);
914 * Free all CoW staging blocks that are still referenced by the ondisk refcount
915 * metadata. The ondisk metadata does not track which inode created the
916 * staging extent, so callers must ensure that there are no cached inodes with
917 * live CoW staging extents.
920 xfs_reflink_recover_cow(
921 struct xfs_mount *mp)
923 struct xfs_perag *pag;
927 if (!xfs_has_reflink(mp))
930 for_each_perag(mp, agno, pag) {
931 error = xfs_refcount_recover_cow_leftovers(mp, pag);
942 * Reflinking (Block) Ranges of Two Files Together
944 * First, ensure that the reflink flag is set on both inodes. The flag is an
945 * optimization to avoid unnecessary refcount btree lookups in the write path.
947 * Now we can iteratively remap the range of extents (and holes) in src to the
948 * corresponding ranges in dest. Let drange and srange denote the ranges of
949 * logical blocks in dest and src touched by the reflink operation.
951 * While the length of drange is greater than zero,
952 * - Read src's bmbt at the start of srange ("imap")
953 * - If imap doesn't exist, make imap appear to start at the end of srange
955 * - If imap starts before srange, advance imap to start at srange.
956 * - If imap goes beyond srange, truncate imap to end at the end of srange.
957 * - Punch (imap start - srange start + imap len) blocks from dest at
958 * offset (drange start).
959 * - If imap points to a real range of pblks,
960 * > Increase the refcount of the imap's pblks
961 * > Map imap's pblks into dest at the offset
962 * (drange start + imap start - srange start)
963 * - Advance drange and srange by (imap start - srange start + imap len)
965 * Finally, if the reflink made dest longer, update both the in-core and
966 * on-disk file sizes.
968 * ASCII Art Demonstration:
970 * Let's say we want to reflink this source file:
972 * ----SSSSSSS-SSSSS----SSSSSS (src file)
973 * <-------------------->
975 * into this destination file:
977 * --DDDDDDDDDDDDDDDDDDD--DDD (dest file)
978 * <-------------------->
979 * '-' means a hole, and 'S' and 'D' are written blocks in the src and dest.
980 * Observe that the range has different logical offsets in either file.
982 * Consider that the first extent in the source file doesn't line up with our
983 * reflink range. Unmapping and remapping are separate operations, so we can
984 * unmap more blocks from the destination file than we remap.
986 * ----SSSSSSS-SSSSS----SSSSSS
988 * --DDDDD---------DDDDD--DDD
991 * Now remap the source extent into the destination file:
993 * ----SSSSSSS-SSSSS----SSSSSS
995 * --DDDDD--SSSSSSSDDDDD--DDD
998 * Do likewise with the second hole and extent in our range. Holes in the
999 * unmap range don't affect our operation.
1001 * ----SSSSSSS-SSSSS----SSSSSS
1003 * --DDDDD--SSSSSSS-SSSSS-DDD
1006 * Finally, unmap and remap part of the third extent. This will increase the
1007 * size of the destination file.
1009 * ----SSSSSSS-SSSSS----SSSSSS
1011 * --DDDDD--SSSSSSS-SSSSS----SSS
1014 * Once we update the destination file's i_size, we're done.
1018 * Ensure the reflink bit is set in both inodes.
1021 xfs_reflink_set_inode_flag(
1022 struct xfs_inode *src,
1023 struct xfs_inode *dest)
1025 struct xfs_mount *mp = src->i_mount;
1027 struct xfs_trans *tp;
1029 if (xfs_is_reflink_inode(src) && xfs_is_reflink_inode(dest))
1032 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
1036 /* Lock both files against IO */
1037 if (src->i_ino == dest->i_ino)
1038 xfs_ilock(src, XFS_ILOCK_EXCL);
1040 xfs_lock_two_inodes(src, XFS_ILOCK_EXCL, dest, XFS_ILOCK_EXCL);
1042 if (!xfs_is_reflink_inode(src)) {
1043 trace_xfs_reflink_set_inode_flag(src);
1044 xfs_trans_ijoin(tp, src, XFS_ILOCK_EXCL);
1045 src->i_diflags2 |= XFS_DIFLAG2_REFLINK;
1046 xfs_trans_log_inode(tp, src, XFS_ILOG_CORE);
1047 xfs_ifork_init_cow(src);
1049 xfs_iunlock(src, XFS_ILOCK_EXCL);
1051 if (src->i_ino == dest->i_ino)
1054 if (!xfs_is_reflink_inode(dest)) {
1055 trace_xfs_reflink_set_inode_flag(dest);
1056 xfs_trans_ijoin(tp, dest, XFS_ILOCK_EXCL);
1057 dest->i_diflags2 |= XFS_DIFLAG2_REFLINK;
1058 xfs_trans_log_inode(tp, dest, XFS_ILOG_CORE);
1059 xfs_ifork_init_cow(dest);
1061 xfs_iunlock(dest, XFS_ILOCK_EXCL);
1064 error = xfs_trans_commit(tp);
1070 trace_xfs_reflink_set_inode_flag_error(dest, error, _RET_IP_);
1075 * Update destination inode size & cowextsize hint, if necessary.
1078 xfs_reflink_update_dest(
1079 struct xfs_inode *dest,
1081 xfs_extlen_t cowextsize,
1082 unsigned int remap_flags)
1084 struct xfs_mount *mp = dest->i_mount;
1085 struct xfs_trans *tp;
1088 if (newlen <= i_size_read(VFS_I(dest)) && cowextsize == 0)
1091 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
1095 xfs_ilock(dest, XFS_ILOCK_EXCL);
1096 xfs_trans_ijoin(tp, dest, XFS_ILOCK_EXCL);
1098 if (newlen > i_size_read(VFS_I(dest))) {
1099 trace_xfs_reflink_update_inode_size(dest, newlen);
1100 i_size_write(VFS_I(dest), newlen);
1101 dest->i_disk_size = newlen;
1105 dest->i_cowextsize = cowextsize;
1106 dest->i_diflags2 |= XFS_DIFLAG2_COWEXTSIZE;
1109 xfs_trans_log_inode(tp, dest, XFS_ILOG_CORE);
1111 error = xfs_trans_commit(tp);
1117 trace_xfs_reflink_update_inode_size_error(dest, error, _RET_IP_);
1122 * Do we have enough reserve in this AG to handle a reflink? The refcount
1123 * btree already reserved all the space it needs, but the rmap btree can grow
1124 * infinitely, so we won't allow more reflinks when the AG is down to the
1128 xfs_reflink_ag_has_free_space(
1129 struct xfs_mount *mp,
1130 xfs_agnumber_t agno)
1132 struct xfs_perag *pag;
1135 if (!xfs_has_rmapbt(mp))
1138 pag = xfs_perag_get(mp, agno);
1139 if (xfs_ag_resv_critical(pag, XFS_AG_RESV_RMAPBT) ||
1140 xfs_ag_resv_critical(pag, XFS_AG_RESV_METADATA))
1147 * Remap the given extent into the file. The dmap blockcount will be set to
1148 * the number of blocks that were actually remapped.
1151 xfs_reflink_remap_extent(
1152 struct xfs_inode *ip,
1153 struct xfs_bmbt_irec *dmap,
1154 xfs_off_t new_isize)
1156 struct xfs_bmbt_irec smap;
1157 struct xfs_mount *mp = ip->i_mount;
1158 struct xfs_trans *tp;
1161 unsigned int resblks;
1162 bool quota_reserved = true;
1164 bool dmap_written = xfs_bmap_is_written_extent(dmap);
1170 * Start a rolling transaction to switch the mappings.
1172 * Adding a written extent to the extent map can cause a bmbt split,
1173 * and removing a mapped extent from the extent can cause a bmbt split.
1174 * The two operations cannot both cause a split since they operate on
1175 * the same index in the bmap btree, so we only need a reservation for
1176 * one bmbt split if either thing is happening. However, we haven't
1177 * locked the inode yet, so we reserve assuming this is the case.
1179 * The first allocation call tries to reserve enough space to handle
1180 * mapping dmap into a sparse part of the file plus the bmbt split. We
1181 * haven't locked the inode or read the existing mapping yet, so we do
1182 * not know for sure that we need the space. This should succeed most
1185 * If the first attempt fails, try again but reserving only enough
1186 * space to handle a bmbt split. This is the hard minimum requirement,
1187 * and we revisit quota reservations later when we know more about what
1190 resblks = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
1191 error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write,
1192 resblks + dmap->br_blockcount, 0, false, &tp);
1193 if (error == -EDQUOT || error == -ENOSPC) {
1194 quota_reserved = false;
1195 error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write,
1196 resblks, 0, false, &tp);
1202 * Read what's currently mapped in the destination file into smap.
1203 * If smap isn't a hole, we will have to remove it before we can add
1204 * dmap to the destination file.
1207 error = xfs_bmapi_read(ip, dmap->br_startoff, dmap->br_blockcount,
1211 ASSERT(nimaps == 1 && smap.br_startoff == dmap->br_startoff);
1212 smap_real = xfs_bmap_is_real_extent(&smap);
1215 * We can only remap as many blocks as the smaller of the two extent
1216 * maps, because we can only remap one extent at a time.
1218 dmap->br_blockcount = min(dmap->br_blockcount, smap.br_blockcount);
1219 ASSERT(dmap->br_blockcount == smap.br_blockcount);
1221 trace_xfs_reflink_remap_extent_dest(ip, &smap);
1224 * Two extents mapped to the same physical block must not have
1225 * different states; that's filesystem corruption. Move on to the next
1226 * extent if they're both holes or both the same physical extent.
1228 if (dmap->br_startblock == smap.br_startblock) {
1229 if (dmap->br_state != smap.br_state)
1230 error = -EFSCORRUPTED;
1234 /* If both extents are unwritten, leave them alone. */
1235 if (dmap->br_state == XFS_EXT_UNWRITTEN &&
1236 smap.br_state == XFS_EXT_UNWRITTEN)
1239 /* No reflinking if the AG of the dest mapping is low on space. */
1241 error = xfs_reflink_ag_has_free_space(mp,
1242 XFS_FSB_TO_AGNO(mp, dmap->br_startblock));
1248 * Increase quota reservation if we think the quota block counter for
1249 * this file could increase.
1251 * If we are mapping a written extent into the file, we need to have
1252 * enough quota block count reservation to handle the blocks in that
1253 * extent. We log only the delta to the quota block counts, so if the
1254 * extent we're unmapping also has blocks allocated to it, we don't
1255 * need a quota reservation for the extent itself.
1257 * Note that if we're replacing a delalloc reservation with a written
1258 * extent, we have to take the full quota reservation because removing
1259 * the delalloc reservation gives the block count back to the quota
1260 * count. This is suboptimal, but the VFS flushed the dest range
1261 * before we started. That should have removed all the delalloc
1262 * reservations, but we code defensively.
1264 * xfs_trans_alloc_inode above already tried to grab an even larger
1265 * quota reservation, and kicked off a blockgc scan if it couldn't.
1266 * If we can't get a potentially smaller quota reservation now, we're
1269 if (!quota_reserved && !smap_real && dmap_written) {
1270 error = xfs_trans_reserve_quota_nblks(tp, ip,
1271 dmap->br_blockcount, 0, false);
1282 error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK, iext_delta);
1283 if (error == -EFBIG)
1284 error = xfs_iext_count_upgrade(tp, ip, iext_delta);
1290 * If the extent we're unmapping is backed by storage (written
1291 * or not), unmap the extent and drop its refcount.
1293 xfs_bmap_unmap_extent(tp, ip, &smap);
1294 xfs_refcount_decrease_extent(tp, &smap);
1295 qdelta -= smap.br_blockcount;
1296 } else if (smap.br_startblock == DELAYSTARTBLOCK) {
1300 * If the extent we're unmapping is a delalloc reservation,
1301 * we can use the regular bunmapi function to release the
1302 * incore state. Dropping the delalloc reservation takes care
1303 * of the quota reservation for us.
1305 error = xfs_bunmapi(NULL, ip, smap.br_startoff,
1306 smap.br_blockcount, 0, 1, &done);
1313 * If the extent we're sharing is backed by written storage, increase
1314 * its refcount and map it into the file.
1317 xfs_refcount_increase_extent(tp, dmap);
1318 xfs_bmap_map_extent(tp, ip, dmap);
1319 qdelta += dmap->br_blockcount;
1322 xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, qdelta);
1324 /* Update dest isize if needed. */
1325 newlen = XFS_FSB_TO_B(mp, dmap->br_startoff + dmap->br_blockcount);
1326 newlen = min_t(xfs_off_t, newlen, new_isize);
1327 if (newlen > i_size_read(VFS_I(ip))) {
1328 trace_xfs_reflink_update_inode_size(ip, newlen);
1329 i_size_write(VFS_I(ip), newlen);
1330 ip->i_disk_size = newlen;
1331 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
1334 /* Commit everything and unlock. */
1335 error = xfs_trans_commit(tp);
1339 xfs_trans_cancel(tp);
1341 xfs_iunlock(ip, XFS_ILOCK_EXCL);
1344 trace_xfs_reflink_remap_extent_error(ip, error, _RET_IP_);
1348 /* Remap a range of one file to the other. */
1350 xfs_reflink_remap_blocks(
1351 struct xfs_inode *src,
1353 struct xfs_inode *dest,
1358 struct xfs_bmbt_irec imap;
1359 struct xfs_mount *mp = src->i_mount;
1360 xfs_fileoff_t srcoff = XFS_B_TO_FSBT(mp, pos_in);
1361 xfs_fileoff_t destoff = XFS_B_TO_FSBT(mp, pos_out);
1363 xfs_filblks_t remapped_len = 0;
1364 xfs_off_t new_isize = pos_out + remap_len;
1368 len = min_t(xfs_filblks_t, XFS_B_TO_FSB(mp, remap_len),
1371 trace_xfs_reflink_remap_blocks(src, srcoff, len, dest, destoff);
1374 unsigned int lock_mode;
1376 /* Read extent from the source file */
1378 lock_mode = xfs_ilock_data_map_shared(src);
1379 error = xfs_bmapi_read(src, srcoff, len, &imap, &nimaps, 0);
1380 xfs_iunlock(src, lock_mode);
1384 * The caller supposedly flushed all dirty pages in the source
1385 * file range, which means that writeback should have allocated
1386 * or deleted all delalloc reservations in that range. If we
1387 * find one, that's a good sign that something is seriously
1390 ASSERT(nimaps == 1 && imap.br_startoff == srcoff);
1391 if (imap.br_startblock == DELAYSTARTBLOCK) {
1392 ASSERT(imap.br_startblock != DELAYSTARTBLOCK);
1393 error = -EFSCORRUPTED;
1397 trace_xfs_reflink_remap_extent_src(src, &imap);
1399 /* Remap into the destination file at the given offset. */
1400 imap.br_startoff = destoff;
1401 error = xfs_reflink_remap_extent(dest, &imap, new_isize);
1405 if (fatal_signal_pending(current)) {
1410 /* Advance drange/srange */
1411 srcoff += imap.br_blockcount;
1412 destoff += imap.br_blockcount;
1413 len -= imap.br_blockcount;
1414 remapped_len += imap.br_blockcount;
1418 trace_xfs_reflink_remap_blocks_error(dest, error, _RET_IP_);
1419 *remapped = min_t(loff_t, remap_len,
1420 XFS_FSB_TO_B(src->i_mount, remapped_len));
1425 * If we're reflinking to a point past the destination file's EOF, we must
1426 * zero any speculative post-EOF preallocations that sit between the old EOF
1427 * and the destination file offset.
1430 xfs_reflink_zero_posteof(
1431 struct xfs_inode *ip,
1434 loff_t isize = i_size_read(VFS_I(ip));
1439 trace_xfs_zero_eof(ip, isize, pos - isize);
1440 return xfs_zero_range(ip, isize, pos - isize, NULL);
1444 * Prepare two files for range cloning. Upon a successful return both inodes
1445 * will have the iolock and mmaplock held, the page cache of the out file will
1446 * be truncated, and any leases on the out file will have been broken. This
1447 * function borrows heavily from xfs_file_aio_write_checks.
1449 * The VFS allows partial EOF blocks to "match" for dedupe even though it hasn't
1450 * checked that the bytes beyond EOF physically match. Hence we cannot use the
1451 * EOF block in the source dedupe range because it's not a complete block match,
1452 * hence can introduce a corruption into the file that has it's block replaced.
1454 * In similar fashion, the VFS file cloning also allows partial EOF blocks to be
1455 * "block aligned" for the purposes of cloning entire files. However, if the
1456 * source file range includes the EOF block and it lands within the existing EOF
1457 * of the destination file, then we can expose stale data from beyond the source
1458 * file EOF in the destination file.
1460 * XFS doesn't support partial block sharing, so in both cases we have check
1461 * these cases ourselves. For dedupe, we can simply round the length to dedupe
1462 * down to the previous whole block and ignore the partial EOF block. While this
1463 * means we can't dedupe the last block of a file, this is an acceptible
1464 * tradeoff for simplicity on implementation.
1466 * For cloning, we want to share the partial EOF block if it is also the new EOF
1467 * block of the destination file. If the partial EOF block lies inside the
1468 * existing destination EOF, then we have to abort the clone to avoid exposing
1469 * stale data in the destination file. Hence we reject these clone attempts with
1470 * -EINVAL in this case.
1473 xfs_reflink_remap_prep(
1474 struct file *file_in,
1476 struct file *file_out,
1479 unsigned int remap_flags)
1481 struct inode *inode_in = file_inode(file_in);
1482 struct xfs_inode *src = XFS_I(inode_in);
1483 struct inode *inode_out = file_inode(file_out);
1484 struct xfs_inode *dest = XFS_I(inode_out);
1487 /* Lock both files against IO */
1488 ret = xfs_ilock2_io_mmap(src, dest);
1492 /* Check file eligibility and prepare for block sharing. */
1494 /* Don't reflink realtime inodes */
1495 if (XFS_IS_REALTIME_INODE(src) || XFS_IS_REALTIME_INODE(dest))
1498 /* Don't share DAX file data with non-DAX file. */
1499 if (IS_DAX(inode_in) != IS_DAX(inode_out))
1502 if (!IS_DAX(inode_in))
1503 ret = generic_remap_file_range_prep(file_in, pos_in, file_out,
1504 pos_out, len, remap_flags);
1506 ret = dax_remap_file_range_prep(file_in, pos_in, file_out,
1507 pos_out, len, remap_flags, &xfs_read_iomap_ops);
1508 if (ret || *len == 0)
1511 /* Attach dquots to dest inode before changing block map */
1512 ret = xfs_qm_dqattach(dest);
1517 * Zero existing post-eof speculative preallocations in the destination
1520 ret = xfs_reflink_zero_posteof(dest, pos_out);
1524 /* Set flags and remap blocks. */
1525 ret = xfs_reflink_set_inode_flag(src, dest);
1530 * If pos_out > EOF, we may have dirtied blocks between EOF and
1531 * pos_out. In that case, we need to extend the flush and unmap to cover
1532 * from EOF to the end of the copy length.
1534 if (pos_out > XFS_ISIZE(dest)) {
1535 loff_t flen = *len + (pos_out - XFS_ISIZE(dest));
1536 ret = xfs_flush_unmap_range(dest, XFS_ISIZE(dest), flen);
1538 ret = xfs_flush_unmap_range(dest, pos_out, *len);
1543 xfs_iflags_set(src, XFS_IREMAPPING);
1544 if (inode_in != inode_out)
1545 xfs_ilock_demote(src, XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL);
1549 xfs_iunlock2_io_mmap(src, dest);
1553 /* Does this inode need the reflink flag? */
1555 xfs_reflink_inode_has_shared_extents(
1556 struct xfs_trans *tp,
1557 struct xfs_inode *ip,
1560 struct xfs_bmbt_irec got;
1561 struct xfs_mount *mp = ip->i_mount;
1562 struct xfs_ifork *ifp;
1563 struct xfs_iext_cursor icur;
1567 ifp = xfs_ifork_ptr(ip, XFS_DATA_FORK);
1568 error = xfs_iread_extents(tp, ip, XFS_DATA_FORK);
1572 *has_shared = false;
1573 found = xfs_iext_lookup_extent(ip, ifp, 0, &icur, &got);
1575 struct xfs_perag *pag;
1576 xfs_agblock_t agbno;
1581 if (isnullstartblock(got.br_startblock) ||
1582 got.br_state != XFS_EXT_NORM)
1585 pag = xfs_perag_get(mp, XFS_FSB_TO_AGNO(mp, got.br_startblock));
1586 agbno = XFS_FSB_TO_AGBNO(mp, got.br_startblock);
1587 aglen = got.br_blockcount;
1588 error = xfs_reflink_find_shared(pag, tp, agbno, aglen,
1589 &rbno, &rlen, false);
1594 /* Is there still a shared block here? */
1595 if (rbno != NULLAGBLOCK) {
1600 found = xfs_iext_next_extent(ifp, &icur, &got);
1607 * Clear the inode reflink flag if there are no shared extents.
1609 * The caller is responsible for joining the inode to the transaction passed in.
1610 * The inode will be joined to the transaction that is returned to the caller.
1613 xfs_reflink_clear_inode_flag(
1614 struct xfs_inode *ip,
1615 struct xfs_trans **tpp)
1620 ASSERT(xfs_is_reflink_inode(ip));
1622 error = xfs_reflink_inode_has_shared_extents(*tpp, ip, &needs_flag);
1623 if (error || needs_flag)
1627 * We didn't find any shared blocks so turn off the reflink flag.
1628 * First, get rid of any leftover CoW mappings.
1630 error = xfs_reflink_cancel_cow_blocks(ip, tpp, 0, XFS_MAX_FILEOFF,
1635 /* Clear the inode flag. */
1636 trace_xfs_reflink_unset_inode_flag(ip);
1637 ip->i_diflags2 &= ~XFS_DIFLAG2_REFLINK;
1638 xfs_inode_clear_cowblocks_tag(ip);
1639 xfs_trans_log_inode(*tpp, ip, XFS_ILOG_CORE);
1645 * Clear the inode reflink flag if there are no shared extents and the size
1649 xfs_reflink_try_clear_inode_flag(
1650 struct xfs_inode *ip)
1652 struct xfs_mount *mp = ip->i_mount;
1653 struct xfs_trans *tp;
1656 /* Start a rolling transaction to remove the mappings */
1657 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, 0, &tp);
1661 xfs_ilock(ip, XFS_ILOCK_EXCL);
1662 xfs_trans_ijoin(tp, ip, 0);
1664 error = xfs_reflink_clear_inode_flag(ip, &tp);
1668 error = xfs_trans_commit(tp);
1672 xfs_iunlock(ip, XFS_ILOCK_EXCL);
1675 xfs_trans_cancel(tp);
1677 xfs_iunlock(ip, XFS_ILOCK_EXCL);
1682 * Pre-COW all shared blocks within a given byte range of a file and turn off
1683 * the reflink flag if we unshare all of the file's blocks.
1686 xfs_reflink_unshare(
1687 struct xfs_inode *ip,
1691 struct inode *inode = VFS_I(ip);
1694 if (!xfs_is_reflink_inode(ip))
1697 trace_xfs_reflink_unshare(ip, offset, len);
1699 inode_dio_wait(inode);
1702 error = dax_file_unshare(inode, offset, len,
1703 &xfs_dax_write_iomap_ops);
1705 error = iomap_file_unshare(inode, offset, len,
1706 &xfs_buffered_write_iomap_ops);
1710 error = filemap_write_and_wait_range(inode->i_mapping, offset,
1715 /* Turn off the reflink flag if possible. */
1716 error = xfs_reflink_try_clear_inode_flag(ip);
1722 trace_xfs_reflink_unshare_error(ip, error, _RET_IP_);