1 files changed, 504 insertions, 335 deletions

diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index b0ce04ffd3cd..93bdd25680bc 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -27,7 +27,7 @@
 #include "xfs_quota.h"
 #include "xfs_reflink.h"
 #include "xfs_iomap.h"
-#include "xfs_sb.h"
+#include "xfs_ag.h"
 #include "xfs_ag_resv.h"
 
 /*
@@ -125,11 +125,10 @@
  * shared blocks.  If there are no shared extents, fbno and flen will
  * be set to NULLAGBLOCK and 0, respectively.
  */
-int
+static int
 xfs_reflink_find_shared(
-	struct xfs_mount	*mp,
+	struct xfs_perag	*pag,
 	struct xfs_trans	*tp,
-	xfs_agnumber_t		agno,
 	xfs_agblock_t		agbno,
 	xfs_extlen_t		aglen,
 	xfs_agblock_t		*fbno,
@@ -140,11 +139,11 @@ xfs_reflink_find_shared(
 	struct xfs_btree_cur	*cur;
 	int			error;
 
-	error = xfs_alloc_read_agf(mp, tp, agno, 0, &agbp);
+	error = xfs_alloc_read_agf(pag, tp, 0, &agbp);
 	if (error)
 		return error;
 
-	cur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno);
+	cur = xfs_refcountbt_init_cursor(pag->pag_mount, tp, agbp, pag);
 
 	error = xfs_refcount_find_shared(cur, agbno, aglen, fbno, flen,
 			find_end_of_shared);
@@ -171,7 +170,8 @@ xfs_reflink_trim_around_shared(
 	struct xfs_bmbt_irec	*irec,
 	bool			*shared)
 {
-	xfs_agnumber_t		agno;
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_perag	*pag;
 	xfs_agblock_t		agbno;
 	xfs_extlen_t		aglen;
 	xfs_agblock_t		fbno;
@@ -179,19 +179,20 @@ xfs_reflink_trim_around_shared(
 	int			error = 0;
 
 	/* Holes, unwritten, and delalloc extents cannot be shared */
-	if (!xfs_is_cow_inode(ip) || !xfs_bmap_is_real_extent(irec)) {
+	if (!xfs_is_cow_inode(ip) || !xfs_bmap_is_written_extent(irec)) {
 		*shared = false;
 		return 0;
 	}
 
 	trace_xfs_reflink_trim_around_shared(ip, irec);
 
-	agno = XFS_FSB_TO_AGNO(ip->i_mount, irec->br_startblock);
-	agbno = XFS_FSB_TO_AGBNO(ip->i_mount, irec->br_startblock);
+	pag = xfs_perag_get(mp, XFS_FSB_TO_AGNO(mp, irec->br_startblock));
+	agbno = XFS_FSB_TO_AGBNO(mp, irec->br_startblock);
 	aglen = irec->br_blockcount;
 
-	error = xfs_reflink_find_shared(ip->i_mount, NULL, agno, agbno,
-			aglen, &fbno, &flen, true);
+	error = xfs_reflink_find_shared(pag, NULL, agbno, aglen, &fbno, &flen,
+			true);
+	xfs_perag_put(pag);
 	if (error)
 		return error;
 
@@ -199,7 +200,9 @@ xfs_reflink_trim_around_shared(
 	if (fbno == NULLAGBLOCK) {
 		/* No shared blocks at all. */
 		return 0;
-	} else if (fbno == agbno) {
+	}
+
+	if (fbno == agbno) {
 		/*
 		 * The start of this extent is shared.  Truncate the
 		 * mapping at the end of the shared region so that a
@@ -209,16 +212,16 @@ xfs_reflink_trim_around_shared(
 		irec->br_blockcount = flen;
 		*shared = true;
 		return 0;
-	} else {
-		/*
-		 * There's a shared extent midway through this extent.
-		 * Truncate the mapping at the start of the shared
-		 * extent so that a subsequent iteration starts at the
-		 * start of the shared region.
-		 */
-		irec->br_blockcount = fbno - agbno;
-		return 0;
 	}
+
+	/*
+	 * There's a shared extent midway through this extent.
+	 * Truncate the mapping at the start of the shared
+	 * extent so that a subsequent iteration starts at the
+	 * start of the shared region.
+	 */
+	irec->br_blockcount = fbno - agbno;
+	return 0;
 }
 
 int
@@ -340,9 +343,41 @@ xfs_find_trim_cow_extent(
 	return 0;
 }
 
-/* Allocate all CoW reservations covering a range of blocks in a file. */
-int
-xfs_reflink_allocate_cow(
+static int
+xfs_reflink_convert_unwritten(
+	struct xfs_inode	*ip,
+	struct xfs_bmbt_irec	*imap,
+	struct xfs_bmbt_irec	*cmap,
+	bool			convert_now)
+{
+	xfs_fileoff_t		offset_fsb = imap->br_startoff;
+	xfs_filblks_t		count_fsb = imap->br_blockcount;
+	int			error;
+
+	/*
+	 * cmap might larger than imap due to cowextsize hint.
+	 */
+	xfs_trim_extent(cmap, offset_fsb, count_fsb);
+
+	/*
+	 * COW fork extents are supposed to remain unwritten until we're ready
+	 * to initiate a disk write.  For direct I/O we are going to write the
+	 * data and need the conversion, but for buffered writes we're done.
+	 */
+	if (!convert_now || cmap->br_state == XFS_EXT_NORM)
+		return 0;
+
+	trace_xfs_reflink_convert_cow(ip, cmap);
+
+	error = xfs_reflink_convert_cow_locked(ip, offset_fsb, count_fsb);
+	if (!error)
+		cmap->br_state = XFS_EXT_NORM;
+
+	return error;
+}
+
+static int
+xfs_reflink_fill_cow_hole(
 	struct xfs_inode	*ip,
 	struct xfs_bmbt_irec	*imap,
 	struct xfs_bmbt_irec	*cmap,
@@ -351,59 +386,37 @@ xfs_reflink_allocate_cow(
 	bool			convert_now)
 {
 	struct xfs_mount	*mp = ip->i_mount;
-	xfs_fileoff_t		offset_fsb = imap->br_startoff;
-	xfs_filblks_t		count_fsb = imap->br_blockcount;
 	struct xfs_trans	*tp;
-	int			nimaps, error = 0;
-	bool			found;
 	xfs_filblks_t		resaligned;
-	xfs_extlen_t		resblks = 0;
-
-	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
-	if (!ip->i_cowfp) {
-		ASSERT(!xfs_is_reflink_inode(ip));
-		xfs_ifork_init_cow(ip);
-	}
-
-	error = xfs_find_trim_cow_extent(ip, imap, cmap, shared, &found);
-	if (error || !*shared)
-		return error;
-	if (found)
-		goto convert;
+	xfs_extlen_t		resblks;
+	int			nimaps;
+	int			error;
+	bool			found;
 
 	resaligned = xfs_aligned_fsb_count(imap->br_startoff,
 		imap->br_blockcount, xfs_get_cowextsz_hint(ip));
 	resblks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
 
 	xfs_iunlock(ip, *lockmode);
-	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, 0, &tp);
-	*lockmode = XFS_ILOCK_EXCL;
-	xfs_ilock(ip, *lockmode);
+	*lockmode = 0;
 
+	error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, resblks, 0,
+			false, &tp);
 	if (error)
 		return error;
 
-	error = xfs_qm_dqattach_locked(ip, false);
-	if (error)
-		goto out_trans_cancel;
+	*lockmode = XFS_ILOCK_EXCL;
 
-	/*
-	 * Check for an overlapping extent again now that we dropped the ilock.
-	 */
 	error = xfs_find_trim_cow_extent(ip, imap, cmap, shared, &found);
 	if (error || !*shared)
 		goto out_trans_cancel;
+
 	if (found) {
 		xfs_trans_cancel(tp);
 		goto convert;
 	}
 
-	error = xfs_trans_reserve_quota_nblks(tp, ip, resblks, 0,
-			XFS_QMOPT_RES_REGBLKS);
-	if (error)
-		goto out_trans_cancel;
-
-	xfs_trans_ijoin(tp, ip, 0);
+	ASSERT(cmap->br_startoff > imap->br_startoff);
 
 	/* Allocate the entire reservation as unwritten blocks. */
 	nimaps = 1;
@@ -411,7 +424,7 @@ xfs_reflink_allocate_cow(
 			XFS_BMAPI_COWFORK | XFS_BMAPI_PREALLOC, 0, cmap,
 			&nimaps);
 	if (error)
-		goto out_unreserve;
+		goto out_trans_cancel;
 
 	xfs_inode_set_cowblocks_tag(ip);
 	error = xfs_trans_commit(tp);
@@ -424,26 +437,135 @@ xfs_reflink_allocate_cow(
 	 */
 	if (nimaps == 0)
 		return -ENOSPC;
+
 convert:
-	xfs_trim_extent(cmap, offset_fsb, count_fsb);
-	/*
-	 * COW fork extents are supposed to remain unwritten until we're ready
-	 * to initiate a disk write.  For direct I/O we are going to write the
-	 * data and need the conversion, but for buffered writes we're done.
-	 */
-	if (!convert_now || cmap->br_state == XFS_EXT_NORM)
-		return 0;
-	trace_xfs_reflink_convert_cow(ip, cmap);
-	return xfs_reflink_convert_cow_locked(ip, offset_fsb, count_fsb);
+	return xfs_reflink_convert_unwritten(ip, imap, cmap, convert_now);
+
+out_trans_cancel:
+	xfs_trans_cancel(tp);
+	return error;
+}
+
+static int
+xfs_reflink_fill_delalloc(
+	struct xfs_inode	*ip,
+	struct xfs_bmbt_irec	*imap,
+	struct xfs_bmbt_irec	*cmap,
+	bool			*shared,
+	uint			*lockmode,
+	bool			convert_now)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_trans	*tp;
+	int			nimaps;
+	int			error;
+	bool			found;
+
+	do {
+		xfs_iunlock(ip, *lockmode);
+		*lockmode = 0;
+
+		error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, 0, 0,
+				false, &tp);
+		if (error)
+			return error;
+
+		*lockmode = XFS_ILOCK_EXCL;
+
+		error = xfs_find_trim_cow_extent(ip, imap, cmap, shared,
+				&found);
+		if (error || !*shared)
+			goto out_trans_cancel;
+
+		if (found) {
+			xfs_trans_cancel(tp);
+			break;
+		}
+
+		ASSERT(isnullstartblock(cmap->br_startblock) ||
+		       cmap->br_startblock == DELAYSTARTBLOCK);
+
+		/*
+		 * Replace delalloc reservation with an unwritten extent.
+		 */
+		nimaps = 1;
+		error = xfs_bmapi_write(tp, ip, cmap->br_startoff,
+				cmap->br_blockcount,
+				XFS_BMAPI_COWFORK | XFS_BMAPI_PREALLOC, 0,
+				cmap, &nimaps);
+		if (error)
+			goto out_trans_cancel;
+
+		xfs_inode_set_cowblocks_tag(ip);
+		error = xfs_trans_commit(tp);
+		if (error)
+			return error;
+
+		/*
+		 * Allocation succeeded but the requested range was not even
+		 * partially satisfied?  Bail out!
+		 */
+		if (nimaps == 0)
+			return -ENOSPC;
+	} while (cmap->br_startoff + cmap->br_blockcount <= imap->br_startoff);
+
+	return xfs_reflink_convert_unwritten(ip, imap, cmap, convert_now);
 
-out_unreserve:
-	xfs_trans_unreserve_quota_nblks(tp, ip, (long)resblks, 0,
-			XFS_QMOPT_RES_REGBLKS);
 out_trans_cancel:
 	xfs_trans_cancel(tp);
 	return error;
 }
 
+/* Allocate all CoW reservations covering a range of blocks in a file. */
+int
+xfs_reflink_allocate_cow(
+	struct xfs_inode	*ip,
+	struct xfs_bmbt_irec	*imap,
+	struct xfs_bmbt_irec	*cmap,
+	bool			*shared,
+	uint			*lockmode,
+	bool			convert_now)
+{
+	int			error;
+	bool			found;
+
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+	if (!ip->i_cowfp) {
+		ASSERT(!xfs_is_reflink_inode(ip));
+		xfs_ifork_init_cow(ip);
+	}
+
+	error = xfs_find_trim_cow_extent(ip, imap, cmap, shared, &found);
+	if (error || !*shared)
+		return error;
+
+	/* CoW fork has a real extent */
+	if (found)
+		return xfs_reflink_convert_unwritten(ip, imap, cmap,
+				convert_now);
+
+	/*
+	 * CoW fork does not have an extent and data extent is shared.
+	 * Allocate a real extent in the CoW fork.
+	 */
+	if (cmap->br_startoff > imap->br_startoff)
+		return xfs_reflink_fill_cow_hole(ip, imap, cmap, shared,
+				lockmode, convert_now);
+
+	/*
+	 * CoW fork has a delalloc reservation. Replace it with a real extent.
+	 * There may or may not be a data fork mapping.
+	 */
+	if (isnullstartblock(cmap->br_startblock) ||
+	    cmap->br_startblock == DELAYSTARTBLOCK)
+		return xfs_reflink_fill_delalloc(ip, imap, cmap, shared,
+				lockmode, convert_now);
+
+	/* Shouldn't get here. */
+	ASSERT(0);
+	return -EFSCORRUPTED;
+}
+
 /*
  * Cancel CoW reservations for some block range of an inode.
  *
@@ -461,7 +583,7 @@ xfs_reflink_cancel_cow_blocks(
 	xfs_fileoff_t			end_fsb,
 	bool				cancel_real)
 {
-	struct xfs_ifork		*ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
+	struct xfs_ifork		*ifp = xfs_ifork_ptr(ip, XFS_COW_FORK);
 	struct xfs_bmbt_irec		got, del;
 	struct xfs_iext_cursor		icur;
 	int				error = 0;
@@ -496,7 +618,7 @@ xfs_reflink_cancel_cow_blocks(
 			xfs_refcount_free_cow_extent(*tpp, del.br_startblock,
 					del.br_blockcount);
 
-			xfs_bmap_add_free(*tpp, del.br_startblock,
+			xfs_free_extent_later(*tpp, del.br_startblock,
 					  del.br_blockcount, NULL);
 
 			/* Roll the transaction */
@@ -508,9 +630,8 @@ xfs_reflink_cancel_cow_blocks(
 			xfs_bmap_del_extent_cow(ip, &icur, &got, &del);
 
 			/* Remove the quota reservation */
-			error = xfs_trans_reserve_quota_nblks(NULL, ip,
-					-(long)del.br_blockcount, 0,
-					XFS_QMOPT_RES_REGBLKS);
+			error = xfs_quota_unreserve_blkres(ip,
+					del.br_blockcount);
 			if (error)
 				break;
 		} else {
@@ -596,21 +717,21 @@ out:
 STATIC int
 xfs_reflink_end_cow_extent(
 	struct xfs_inode	*ip,
-	xfs_fileoff_t		offset_fsb,
-	xfs_fileoff_t		*end_fsb)
+	xfs_fileoff_t		*offset_fsb,
+	xfs_fileoff_t		end_fsb)
 {
-	struct xfs_bmbt_irec	got, del;
 	struct xfs_iext_cursor	icur;
+	struct xfs_bmbt_irec	got, del, data;
 	struct xfs_mount	*mp = ip->i_mount;
 	struct xfs_trans	*tp;
-	struct xfs_ifork	*ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
-	xfs_filblks_t		rlen;
+	struct xfs_ifork	*ifp = xfs_ifork_ptr(ip, XFS_COW_FORK);
 	unsigned int		resblks;
+	int			nmaps;
 	int			error;
 
 	/* No COW extents?  That's easy! */
 	if (ifp->if_bytes == 0) {
-		*end_fsb = offset_fsb;
+		*offset_fsb = end_fsb;
 		return 0;
 	}
 
@@ -628,47 +749,79 @@ xfs_reflink_end_cow_extent(
 	xfs_ilock(ip, XFS_ILOCK_EXCL);
 	xfs_trans_ijoin(tp, ip, 0);
 
+	error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
+			XFS_IEXT_REFLINK_END_COW_CNT);
+	if (error == -EFBIG)
+		error = xfs_iext_count_upgrade(tp, ip,
+				XFS_IEXT_REFLINK_END_COW_CNT);
+	if (error)
+		goto out_cancel;
+
 	/*
 	 * In case of racing, overlapping AIO writes no COW extents might be
 	 * left by the time I/O completes for the loser of the race.  In that
 	 * case we are done.
 	 */
-	if (!xfs_iext_lookup_extent_before(ip, ifp, end_fsb, &icur, &got) ||
-	    got.br_startoff + got.br_blockcount <= offset_fsb) {
-		*end_fsb = offset_fsb;
+	if (!xfs_iext_lookup_extent(ip, ifp, *offset_fsb, &icur, &got) ||
+	    got.br_startoff >= end_fsb) {
+		*offset_fsb = end_fsb;
 		goto out_cancel;
 	}
 
 	/*
-	 * Structure copy @got into @del, then trim @del to the range that we
-	 * were asked to remap.  We preserve @got for the eventual CoW fork
-	 * deletion; from now on @del represents the mapping that we're
-	 * actually remapping.
-	 */
-	del = got;
-	xfs_trim_extent(&del, offset_fsb, *end_fsb - offset_fsb);
-
-	ASSERT(del.br_blockcount > 0);
-
-	/*
 	 * Only remap real extents that contain data.  With AIO, speculative
 	 * preallocations can leak into the range we are called upon, and we
-	 * need to skip them.
+	 * need to skip them.  Preserve @got for the eventual CoW fork
+	 * deletion; from now on @del represents the mapping that we're
+	 * actually remapping.
 	 */
-	if (!xfs_bmap_is_real_extent(&got)) {
-		*end_fsb = del.br_startoff;
-		goto out_cancel;
+	while (!xfs_bmap_is_written_extent(&got)) {
+		if (!xfs_iext_next_extent(ifp, &icur, &got) ||
+		    got.br_startoff >= end_fsb) {
+			*offset_fsb = end_fsb;
+			goto out_cancel;
+		}
 	}
+	del = got;
 
-	/* Unmap the old blocks in the data fork. */
-	rlen = del.br_blockcount;
-	error = __xfs_bunmapi(tp, ip, del.br_startoff, &rlen, 0, 1);
+	/* Grab the corresponding mapping in the data fork. */
+	nmaps = 1;
+	error = xfs_bmapi_read(ip, del.br_startoff, del.br_blockcount, &data,
+			&nmaps, 0);
 	if (error)
 		goto out_cancel;
 
-	/* Trim the extent to whatever got unmapped. */
-	xfs_trim_extent(&del, del.br_startoff + rlen, del.br_blockcount - rlen);
-	trace_xfs_reflink_cow_remap(ip, &del);
+	/* We can only remap the smaller of the two extent sizes. */
+	data.br_blockcount = min(data.br_blockcount, del.br_blockcount);
+	del.br_blockcount = data.br_blockcount;
+
+	trace_xfs_reflink_cow_remap_from(ip, &del);
+	trace_xfs_reflink_cow_remap_to(ip, &data);
+
+	if (xfs_bmap_is_real_extent(&data)) {
+		/*
+		 * If the extent we're remapping is backed by storage (written
+		 * or not), unmap the extent and drop its refcount.
+		 */
+		xfs_bmap_unmap_extent(tp, ip, &data);
+		xfs_refcount_decrease_extent(tp, &data);
+		xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT,
+				-data.br_blockcount);
+	} else if (data.br_startblock == DELAYSTARTBLOCK) {
+		int		done;
+
+		/*
+		 * If the extent we're remapping is a delalloc reservation,
+		 * we can use the regular bunmapi function to release the
+		 * incore state.  Dropping the delalloc reservation takes care
+		 * of the quota reservation for us.
+		 */
+		error = xfs_bunmapi(NULL, ip, data.br_startoff,
+				data.br_blockcount, 0, 1, &done);
+		if (error)
+			goto out_cancel;
+		ASSERT(done);
+	}
 
 	/* Free the CoW orphan record. */
 	xfs_refcount_free_cow_extent(tp, del.br_startblock, del.br_blockcount);
@@ -689,7 +842,7 @@ xfs_reflink_end_cow_extent(
 		return error;
 
 	/* Update the caller about how much progress we made. */
-	*end_fsb = del.br_startoff;
+	*offset_fsb = del.br_startoff + del.br_blockcount;
 	return 0;
 
 out_cancel:
@@ -717,11 +870,11 @@ xfs_reflink_end_cow(
 	end_fsb = XFS_B_TO_FSB(ip->i_mount, offset + count);
 
 	/*
-	 * Walk backwards until we're out of the I/O range.  The loop function
+	 * Walk forwards until we've remapped the I/O range.  The loop function
 	 * repeatedly cycles the ILOCK to allocate one transaction per remapped
 	 * extent.
 	 *
-	 * If we're being called by writeback then the the pages will still
+	 * If we're being called by writeback then the pages will still
 	 * have PageWriteback set, which prevents races with reflink remapping
 	 * and truncate.  Reflink remapping prevents races with writeback by
 	 * taking the iolock and mmaplock before flushing the pages and
@@ -749,7 +902,7 @@ xfs_reflink_end_cow(
 	 * blocks will be remapped.
 	 */
 	while (end_fsb > offset_fsb && !error)
-		error = xfs_reflink_end_cow_extent(ip, offset_fsb, &end_fsb);
+		error = xfs_reflink_end_cow_extent(ip, &offset_fsb, end_fsb);
 
 	if (error)
 		trace_xfs_reflink_end_cow_error(ip, error, _RET_IP_);
@@ -757,22 +910,28 @@ xfs_reflink_end_cow(
 }
 
 /*
- * Free leftover CoW reservations that didn't get cleaned out.
+ * Free all CoW staging blocks that are still referenced by the ondisk refcount
+ * metadata.  The ondisk metadata does not track which inode created the
+ * staging extent, so callers must ensure that there are no cached inodes with
+ * live CoW staging extents.
  */
 int
 xfs_reflink_recover_cow(
 	struct xfs_mount	*mp)
 {
+	struct xfs_perag	*pag;
 	xfs_agnumber_t		agno;
 	int			error = 0;
 
-	if (!xfs_sb_version_hasreflink(&mp->m_sb))
+	if (!xfs_has_reflink(mp))
 		return 0;
 
-	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
-		error = xfs_refcount_recover_cow_leftovers(mp, agno);
-		if (error)
+	for_each_perag(mp, agno, pag) {
+		error = xfs_refcount_recover_cow_leftovers(mp, pag);
+		if (error) {
+			xfs_perag_put(pag);
 			break;
+		}
 	}
 
 	return error;
@@ -882,7 +1041,7 @@ xfs_reflink_set_inode_flag(
 	if (!xfs_is_reflink_inode(src)) {
 		trace_xfs_reflink_set_inode_flag(src);
 		xfs_trans_ijoin(tp, src, XFS_ILOCK_EXCL);
-		src->i_d.di_flags2 |= XFS_DIFLAG2_REFLINK;
+		src->i_diflags2 |= XFS_DIFLAG2_REFLINK;
 		xfs_trans_log_inode(tp, src, XFS_ILOG_CORE);
 		xfs_ifork_init_cow(src);
 	} else
@@ -894,7 +1053,7 @@ xfs_reflink_set_inode_flag(
 	if (!xfs_is_reflink_inode(dest)) {
 		trace_xfs_reflink_set_inode_flag(dest);
 		xfs_trans_ijoin(tp, dest, XFS_ILOCK_EXCL);
-		dest->i_d.di_flags2 |= XFS_DIFLAG2_REFLINK;
+		dest->i_diflags2 |= XFS_DIFLAG2_REFLINK;
 		xfs_trans_log_inode(tp, dest, XFS_ILOG_CORE);
 		xfs_ifork_init_cow(dest);
 	} else
@@ -938,12 +1097,12 @@ xfs_reflink_update_dest(
 	if (newlen > i_size_read(VFS_I(dest))) {
 		trace_xfs_reflink_update_inode_size(dest, newlen);
 		i_size_write(VFS_I(dest), newlen);
-		dest->i_d.di_size = newlen;
+		dest->i_disk_size = newlen;
 	}
 
 	if (cowextsize) {
-		dest->i_d.di_cowextsize = cowextsize;
-		dest->i_d.di_flags2 |= XFS_DIFLAG2_COWEXTSIZE;
+		dest->i_cowextsize = cowextsize;
+		dest->i_diflags2 |= XFS_DIFLAG2_COWEXTSIZE;
 	}
 
 	xfs_trans_log_inode(tp, dest, XFS_ILOG_CORE);
@@ -972,7 +1131,7 @@ xfs_reflink_ag_has_free_space(
 	struct xfs_perag	*pag;
 	int			error = 0;
 
-	if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
+	if (!xfs_has_rmapbt(mp))
 		return 0;
 
 	pag = xfs_perag_get(mp, agno);
@@ -984,127 +1143,208 @@ xfs_reflink_ag_has_free_space(
 }
 
 /*
- * Unmap a range of blocks from a file, then map other blocks into the hole.
- * The range to unmap is (destoff : destoff + srcioff + irec->br_blockcount).
- * The extent irec is mapped into dest at irec->br_startoff.
+ * Remap the given extent into the file.  The dmap blockcount will be set to
+ * the number of blocks that were actually remapped.
  */
 STATIC int
 xfs_reflink_remap_extent(
 	struct xfs_inode	*ip,
-	struct xfs_bmbt_irec	*irec,
-	xfs_fileoff_t		destoff,
+	struct xfs_bmbt_irec	*dmap,
 	xfs_off_t		new_isize)
 {
+	struct xfs_bmbt_irec	smap;
 	struct xfs_mount	*mp = ip->i_mount;
-	bool			real_extent = xfs_bmap_is_real_extent(irec);
 	struct xfs_trans	*tp;
-	unsigned int		resblks;
-	struct xfs_bmbt_irec	uirec;
-	xfs_filblks_t		rlen;
-	xfs_filblks_t		unmap_len;
 	xfs_off_t		newlen;
+	int64_t			qdelta = 0;
+	unsigned int		resblks;
+	bool			quota_reserved = true;
+	bool			smap_real;
+	bool			dmap_written = xfs_bmap_is_written_extent(dmap);
+	int			iext_delta = 0;
+	int			nimaps;
 	int			error;
 
-	unmap_len = irec->br_startoff + irec->br_blockcount - destoff;
-	trace_xfs_reflink_punch_range(ip, destoff, unmap_len);
-
-	/* No reflinking if we're low on space */
-	if (real_extent) {
-		error = xfs_reflink_ag_has_free_space(mp,
-				XFS_FSB_TO_AGNO(mp, irec->br_startblock));
-		if (error)
-			goto out;
+	/*
+	 * Start a rolling transaction to switch the mappings.
+	 *
+	 * Adding a written extent to the extent map can cause a bmbt split,
+	 * and removing a mapped extent from the extent can cause a bmbt split.
+	 * The two operations cannot both cause a split since they operate on
+	 * the same index in the bmap btree, so we only need a reservation for
+	 * one bmbt split if either thing is happening.  However, we haven't
+	 * locked the inode yet, so we reserve assuming this is the case.
+	 *
+	 * The first allocation call tries to reserve enough space to handle
+	 * mapping dmap into a sparse part of the file plus the bmbt split.  We
+	 * haven't locked the inode or read the existing mapping yet, so we do
+	 * not know for sure that we need the space.  This should succeed most
+	 * of the time.
+	 *
+	 * If the first attempt fails, try again but reserving only enough
+	 * space to handle a bmbt split.  This is the hard minimum requirement,
+	 * and we revisit quota reservations later when we know more about what
+	 * we're remapping.
+	 */
+	resblks = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
+	error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write,
+			resblks + dmap->br_blockcount, 0, false, &tp);
+	if (error == -EDQUOT || error == -ENOSPC) {
+		quota_reserved = false;
+		error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write,
+				resblks, 0, false, &tp);
 	}
-
-	/* Start a rolling transaction to switch the mappings */
-	resblks = XFS_EXTENTADD_SPACE_RES(ip->i_mount, XFS_DATA_FORK);
-	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, 0, &tp);
 	if (error)
 		goto out;
 
-	xfs_ilock(ip, XFS_ILOCK_EXCL);
-	xfs_trans_ijoin(tp, ip, 0);
+	/*
+	 * Read what's currently mapped in the destination file into smap.
+	 * If smap isn't a hole, we will have to remove it before we can add
+	 * dmap to the destination file.
+	 */
+	nimaps = 1;
+	error = xfs_bmapi_read(ip, dmap->br_startoff, dmap->br_blockcount,
+			&smap, &nimaps, 0);
+	if (error)
+		goto out_cancel;
+	ASSERT(nimaps == 1 && smap.br_startoff == dmap->br_startoff);
+	smap_real = xfs_bmap_is_real_extent(&smap);
 
-	/* If we're not just clearing space, then do we have enough quota? */
-	if (real_extent) {
-		error = xfs_trans_reserve_quota_nblks(tp, ip,
-				irec->br_blockcount, 0, XFS_QMOPT_RES_REGBLKS);
-		if (error)
-			goto out_cancel;
+	/*
+	 * We can only remap as many blocks as the smaller of the two extent
+	 * maps, because we can only remap one extent at a time.
+	 */
+	dmap->br_blockcount = min(dmap->br_blockcount, smap.br_blockcount);
+	ASSERT(dmap->br_blockcount == smap.br_blockcount);
+
+	trace_xfs_reflink_remap_extent_dest(ip, &smap);
+
+	/*
+	 * Two extents mapped to the same physical block must not have
+	 * different states; that's filesystem corruption.  Move on to the next
+	 * extent if they're both holes or both the same physical extent.
+	 */
+	if (dmap->br_startblock == smap.br_startblock) {
+		if (dmap->br_state != smap.br_state)
+			error = -EFSCORRUPTED;
+		goto out_cancel;
 	}
 
-	trace_xfs_reflink_remap(ip, irec->br_startoff,
-				irec->br_blockcount, irec->br_startblock);
+	/* If both extents are unwritten, leave them alone. */
+	if (dmap->br_state == XFS_EXT_UNWRITTEN &&
+	    smap.br_state == XFS_EXT_UNWRITTEN)
+		goto out_cancel;
 
-	/* Unmap the old blocks in the data fork. */
-	rlen = unmap_len;
-	while (rlen) {
-		ASSERT(tp->t_firstblock == NULLFSBLOCK);
-		error = __xfs_bunmapi(tp, ip, destoff, &rlen, 0, 1);
+	/* No reflinking if the AG of the dest mapping is low on space. */
+	if (dmap_written) {
+		error = xfs_reflink_ag_has_free_space(mp,
+				XFS_FSB_TO_AGNO(mp, dmap->br_startblock));
 		if (error)
 			goto out_cancel;
+	}
 
-		/*
-		 * Trim the extent to whatever got unmapped.
-		 * Remember, bunmapi works backwards.
-		 */
-		uirec.br_startblock = irec->br_startblock + rlen;
-		uirec.br_startoff = irec->br_startoff + rlen;
-		uirec.br_blockcount = unmap_len - rlen;
-		unmap_len = rlen;
-
-		/* If this isn't a real mapping, we're done. */
-		if (!real_extent || uirec.br_blockcount == 0)
-			goto next_extent;
+	/*
+	 * Increase quota reservation if we think the quota block counter for
+	 * this file could increase.
+	 *
+	 * If we are mapping a written extent into the file, we need to have
+	 * enough quota block count reservation to handle the blocks in that
+	 * extent.  We log only the delta to the quota block counts, so if the
+	 * extent we're unmapping also has blocks allocated to it, we don't
+	 * need a quota reservation for the extent itself.
+	 *
+	 * Note that if we're replacing a delalloc reservation with a written
+	 * extent, we have to take the full quota reservation because removing
+	 * the delalloc reservation gives the block count back to the quota
+	 * count.  This is suboptimal, but the VFS flushed the dest range
+	 * before we started.  That should have removed all the delalloc
+	 * reservations, but we code defensively.
+	 *
+	 * xfs_trans_alloc_inode above already tried to grab an even larger
+	 * quota reservation, and kicked off a blockgc scan if it couldn't.
+	 * If we can't get a potentially smaller quota reservation now, we're
+	 * done.
+	 */
+	if (!quota_reserved && !smap_real && dmap_written) {
+		error = xfs_trans_reserve_quota_nblks(tp, ip,
+				dmap->br_blockcount, 0, false);
+		if (error)
+			goto out_cancel;
+	}
 
-		trace_xfs_reflink_remap(ip, uirec.br_startoff,
-				uirec.br_blockcount, uirec.br_startblock);
+	if (smap_real)
+		++iext_delta;
 
-		/* Update the refcount tree */
-		xfs_refcount_increase_extent(tp, &uirec);
+	if (dmap_written)
+		++iext_delta;
 
-		/* Map the new blocks into the data fork. */
-		xfs_bmap_map_extent(tp, ip, &uirec);
+	error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK, iext_delta);
+	if (error == -EFBIG)
+		error = xfs_iext_count_upgrade(tp, ip, iext_delta);
+	if (error)
+		goto out_cancel;
 
-		/* Update quota accounting. */
-		xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT,
-				uirec.br_blockcount);
-
-		/* Update dest isize if needed. */
-		newlen = XFS_FSB_TO_B(mp,
-				uirec.br_startoff + uirec.br_blockcount);
-		newlen = min_t(xfs_off_t, newlen, new_isize);
-		if (newlen > i_size_read(VFS_I(ip))) {
-			trace_xfs_reflink_update_inode_size(ip, newlen);
-			i_size_write(VFS_I(ip), newlen);
-			ip->i_d.di_size = newlen;
-			xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
-		}
+	if (smap_real) {
+		/*
+		 * If the extent we're unmapping is backed by storage (written
+		 * or not), unmap the extent and drop its refcount.
+		 */
+		xfs_bmap_unmap_extent(tp, ip, &smap);
+		xfs_refcount_decrease_extent(tp, &smap);
+		qdelta -= smap.br_blockcount;
+	} else if (smap.br_startblock == DELAYSTARTBLOCK) {
+		int		done;
 
-next_extent:
-		/* Process all the deferred stuff. */
-		error = xfs_defer_finish(&tp);
+		/*
+		 * If the extent we're unmapping is a delalloc reservation,
+		 * we can use the regular bunmapi function to release the
+		 * incore state.  Dropping the delalloc reservation takes care
+		 * of the quota reservation for us.
+		 */
+		error = xfs_bunmapi(NULL, ip, smap.br_startoff,
+				smap.br_blockcount, 0, 1, &done);
 		if (error)
 			goto out_cancel;
+		ASSERT(done);
+	}
+
+	/*
+	 * If the extent we're sharing is backed by written storage, increase
+	 * its refcount and map it into the file.
+	 */
+	if (dmap_written) {
+		xfs_refcount_increase_extent(tp, dmap);
+		xfs_bmap_map_extent(tp, ip, dmap);
+		qdelta += dmap->br_blockcount;
+	}
+
+	xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, qdelta);
+
+	/* Update dest isize if needed. */
+	newlen = XFS_FSB_TO_B(mp, dmap->br_startoff + dmap->br_blockcount);
+	newlen = min_t(xfs_off_t, newlen, new_isize);
+	if (newlen > i_size_read(VFS_I(ip))) {
+		trace_xfs_reflink_update_inode_size(ip, newlen);
+		i_size_write(VFS_I(ip), newlen);
+		ip->i_disk_size = newlen;
+		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 	}
 
+	/* Commit everything and unlock. */
 	error = xfs_trans_commit(tp);
-	xfs_iunlock(ip, XFS_ILOCK_EXCL);
-	if (error)
-		goto out;
-	return 0;
+	goto out_unlock;
 
 out_cancel:
 	xfs_trans_cancel(tp);
+out_unlock:
 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 out:
-	trace_xfs_reflink_remap_extent_error(ip, error, _RET_IP_);
+	if (error)
+		trace_xfs_reflink_remap_extent_error(ip, error, _RET_IP_);
 	return error;
 }
 
-/*
- * Iteratively remap one file's extents (and holes) to another's.
- */
+/* Remap a range of one file to the other. */
 int
 xfs_reflink_remap_blocks(
 	struct xfs_inode	*src,
@@ -1115,25 +1355,22 @@ xfs_reflink_remap_blocks(
 	loff_t			*remapped)
 {
 	struct xfs_bmbt_irec	imap;
-	xfs_fileoff_t		srcoff;
-	xfs_fileoff_t		destoff;
+	struct xfs_mount	*mp = src->i_mount;
+	xfs_fileoff_t		srcoff = XFS_B_TO_FSBT(mp, pos_in);
+	xfs_fileoff_t		destoff = XFS_B_TO_FSBT(mp, pos_out);
 	xfs_filblks_t		len;
-	xfs_filblks_t		range_len;
 	xfs_filblks_t		remapped_len = 0;
 	xfs_off_t		new_isize = pos_out + remap_len;
 	int			nimaps;
 	int			error = 0;
 
-	destoff = XFS_B_TO_FSBT(src->i_mount, pos_out);
-	srcoff = XFS_B_TO_FSBT(src->i_mount, pos_in);
-	len = XFS_B_TO_FSB(src->i_mount, remap_len);
+	len = min_t(xfs_filblks_t, XFS_B_TO_FSB(mp, remap_len),
+			XFS_MAX_FILEOFF);
 
-	/* drange = (destoff, destoff + len); srange = (srcoff, srcoff + len) */
-	while (len) {
-		uint		lock_mode;
+	trace_xfs_reflink_remap_blocks(src, srcoff, len, dest, destoff);
 
-		trace_xfs_reflink_remap_blocks_loop(src, srcoff, len,
-				dest, destoff);
+	while (len > 0) {
+		unsigned int	lock_mode;
 
 		/* Read extent from the source file */
 		nimaps = 1;
@@ -1142,18 +1379,25 @@ xfs_reflink_remap_blocks(
 		xfs_iunlock(src, lock_mode);
 		if (error)
 			break;
-		ASSERT(nimaps == 1);
-
-		trace_xfs_reflink_remap_imap(src, srcoff, len, XFS_DATA_FORK,
-				&imap);
+		/*
+		 * The caller supposedly flushed all dirty pages in the source
+		 * file range, which means that writeback should have allocated
+		 * or deleted all delalloc reservations in that range.  If we
+		 * find one, that's a good sign that something is seriously
+		 * wrong here.
+		 */
+		ASSERT(nimaps == 1 && imap.br_startoff == srcoff);
+		if (imap.br_startblock == DELAYSTARTBLOCK) {
+			ASSERT(imap.br_startblock != DELAYSTARTBLOCK);
+			error = -EFSCORRUPTED;
+			break;
+		}
 
-		/* Translate imap into the destination file. */
-		range_len = imap.br_startoff + imap.br_blockcount - srcoff;
-		imap.br_startoff += destoff - srcoff;
+		trace_xfs_reflink_remap_extent_src(src, &imap);
 
-		/* Clear dest from destoff to the end of imap and map it in. */
-		error = xfs_reflink_remap_extent(dest, &imap, destoff,
-				new_isize);
+		/* Remap into the destination file at the given offset. */
+		imap.br_startoff = destoff;
+		error = xfs_reflink_remap_extent(dest, &imap, new_isize);
 		if (error)
 			break;
 
@@ -1163,10 +1407,10 @@ xfs_reflink_remap_blocks(
 		}
 
 		/* Advance drange/srange */
-		srcoff += range_len;
-		destoff += range_len;
-		len -= range_len;
-		remapped_len += range_len;
+		srcoff += imap.br_blockcount;
+		destoff += imap.br_blockcount;
+		len -= imap.br_blockcount;
+		remapped_len += imap.br_blockcount;
 	}
 
 	if (error)
@@ -1177,81 +1421,6 @@ xfs_reflink_remap_blocks(
 }
 
 /*
- * Grab the exclusive iolock for a data copy from src to dest, making sure to
- * abide vfs locking order (lowest pointer value goes first) and breaking the
- * layout leases before proceeding.  The loop is needed because we cannot call
- * the blocking break_layout() with the iolocks held, and therefore have to
- * back out both locks.
- */
-static int
-xfs_iolock_two_inodes_and_break_layout(
-	struct inode		*src,
-	struct inode		*dest)
-{
-	int			error;
-
-	if (src > dest)
-		swap(src, dest);
-
-retry:
-	/* Wait to break both inodes' layouts before we start locking. */
-	error = break_layout(src, true);
-	if (error)
-		return error;
-	if (src != dest) {
-		error = break_layout(dest, true);
-		if (error)
-			return error;
-	}
-
-	/* Lock one inode and make sure nobody got in and leased it. */
-	inode_lock(src);
-	error = break_layout(src, false);
-	if (error) {
-		inode_unlock(src);
-		if (error == -EWOULDBLOCK)
-			goto retry;
-		return error;
-	}
-
-	if (src == dest)
-		return 0;
-
-	/* Lock the other inode and make sure nobody got in and leased it. */
-	inode_lock_nested(dest, I_MUTEX_NONDIR2);
-	error = break_layout(dest, false);
-	if (error) {
-		inode_unlock(src);
-		inode_unlock(dest);
-		if (error == -EWOULDBLOCK)
-			goto retry;
-		return error;
-	}
-
-	return 0;
-}
-
-/* Unlock both inodes after they've been prepped for a range clone. */
-void
-xfs_reflink_remap_unlock(
-	struct file		*file_in,
-	struct file		*file_out)
-{
-	struct inode		*inode_in = file_inode(file_in);
-	struct xfs_inode	*src = XFS_I(inode_in);
-	struct inode		*inode_out = file_inode(file_out);
-	struct xfs_inode	*dest = XFS_I(inode_out);
-	bool			same_inode = (inode_in == inode_out);
-
-	xfs_iunlock(dest, XFS_MMAPLOCK_EXCL);
-	if (!same_inode)
-		xfs_iunlock(src, XFS_MMAPLOCK_EXCL);
-	inode_unlock(inode_out);
-	if (!same_inode)
-		inode_unlock(inode_in);
-}
-
-/*
  * If we're reflinking to a point past the destination file's EOF, we must
  * zero any speculative post-EOF preallocations that sit between the old EOF
  * and the destination file offset.
@@ -1267,8 +1436,7 @@ xfs_reflink_zero_posteof(
 		return 0;
 
 	trace_xfs_zero_eof(ip, isize, pos - isize);
-	return iomap_zero_range(VFS_I(ip), isize, pos - isize, NULL,
-			&xfs_buffered_write_iomap_ops);
+	return xfs_zero_range(ip, isize, pos - isize, NULL);
 }
 
 /*
@@ -1313,18 +1481,12 @@ xfs_reflink_remap_prep(
 	struct xfs_inode	*src = XFS_I(inode_in);
 	struct inode		*inode_out = file_inode(file_out);
 	struct xfs_inode	*dest = XFS_I(inode_out);
-	bool			same_inode = (inode_in == inode_out);
-	ssize_t			ret;
+	int			ret;
 
 	/* Lock both files against IO */
-	ret = xfs_iolock_two_inodes_and_break_layout(inode_in, inode_out);
+	ret = xfs_ilock2_io_mmap(src, dest);
 	if (ret)
 		return ret;
-	if (same_inode)
-		xfs_ilock(src, XFS_MMAPLOCK_EXCL);
-	else
-		xfs_lock_two_inodes(src, XFS_MMAPLOCK_EXCL, dest,
-				XFS_MMAPLOCK_EXCL);
 
 	/* Check file eligibility and prepare for block sharing. */
 	ret = -EINVAL;
@@ -1332,13 +1494,17 @@ xfs_reflink_remap_prep(
 	if (XFS_IS_REALTIME_INODE(src) || XFS_IS_REALTIME_INODE(dest))
 		goto out_unlock;
 
-	/* Don't share DAX file data for now. */
-	if (IS_DAX(inode_in) || IS_DAX(inode_out))
+	/* Don't share DAX file data with non-DAX file. */
+	if (IS_DAX(inode_in) != IS_DAX(inode_out))
 		goto out_unlock;
 
-	ret = generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out,
-			len, remap_flags);
-	if (ret < 0 || *len == 0)
+	if (!IS_DAX(inode_in))
+		ret = generic_remap_file_range_prep(file_in, pos_in, file_out,
+				pos_out, len, remap_flags);
+	else
+		ret = dax_remap_file_range_prep(file_in, pos_in, file_out,
+				pos_out, len, remap_flags, &xfs_read_iomap_ops);
+	if (ret || *len == 0)
 		goto out_unlock;
 
 	/* Attach dquots to dest inode before changing block map */
@@ -1373,9 +1539,9 @@ xfs_reflink_remap_prep(
 	if (ret)
 		goto out_unlock;
 
-	return 1;
+	return 0;
 out_unlock:
-	xfs_reflink_remap_unlock(file_in, file_out);
+	xfs_iunlock2_io_mmap(src, dest);
 	return ret;
 }
 
@@ -1389,36 +1555,37 @@ xfs_reflink_inode_has_shared_extents(
 	struct xfs_bmbt_irec		got;
 	struct xfs_mount		*mp = ip->i_mount;
 	struct xfs_ifork		*ifp;
-	xfs_agnumber_t			agno;
-	xfs_agblock_t			agbno;
-	xfs_extlen_t			aglen;
-	xfs_agblock_t			rbno;
-	xfs_extlen_t			rlen;
 	struct xfs_iext_cursor		icur;
 	bool				found;
 	int				error;
 
-	ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
-	if (!(ifp->if_flags & XFS_IFEXTENTS)) {
-		error = xfs_iread_extents(tp, ip, XFS_DATA_FORK);
-		if (error)
-			return error;
-	}
+	ifp = xfs_ifork_ptr(ip, XFS_DATA_FORK);
+	error = xfs_iread_extents(tp, ip, XFS_DATA_FORK);
+	if (error)
+		return error;
 
 	*has_shared = false;
 	found = xfs_iext_lookup_extent(ip, ifp, 0, &icur, &got);
 	while (found) {
+		struct xfs_perag	*pag;
+		xfs_agblock_t		agbno;
+		xfs_extlen_t		aglen;
+		xfs_agblock_t		rbno;
+		xfs_extlen_t		rlen;
+
 		if (isnullstartblock(got.br_startblock) ||
 		    got.br_state != XFS_EXT_NORM)
 			goto next;
-		agno = XFS_FSB_TO_AGNO(mp, got.br_startblock);
+
+		pag = xfs_perag_get(mp, XFS_FSB_TO_AGNO(mp, got.br_startblock));
 		agbno = XFS_FSB_TO_AGBNO(mp, got.br_startblock);
 		aglen = got.br_blockcount;
-
-		error = xfs_reflink_find_shared(mp, tp, agno, agbno, aglen,
+		error = xfs_reflink_find_shared(pag, tp, agbno, aglen,
 				&rbno, &rlen, false);
+		xfs_perag_put(pag);
 		if (error)
 			return error;
+
 		/* Is there still a shared block here? */
 		if (rbno != NULLAGBLOCK) {
 			*has_shared = true;
@@ -1462,7 +1629,7 @@ xfs_reflink_clear_inode_flag(
 
 	/* Clear the inode flag. */
 	trace_xfs_reflink_unset_inode_flag(ip);
-	ip->i_d.di_flags2 &= ~XFS_DIFLAG2_REFLINK;
+	ip->i_diflags2 &= ~XFS_DIFLAG2_REFLINK;
 	xfs_inode_clear_cowblocks_tag(ip);
 	xfs_trans_log_inode(*tpp, ip, XFS_ILOG_CORE);
 
@@ -1530,7 +1697,9 @@ xfs_reflink_unshare(
 			&xfs_buffered_write_iomap_ops);
 	if (error)
 		goto out;
-	error = filemap_write_and_wait(inode->i_mapping);
+
+	error = filemap_write_and_wait_range(inode->i_mapping, offset,
+			offset + len - 1);
 	if (error)
 		goto out;