From 5a5cfd39bedd4fb4f04999d1a2840f70b6d1abf6 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Fri, 3 Nov 2017 10:34:38 -0700
Subject: [PATCH 47/77] xfs: don't create overlapping extents in
 xfs_bmap_add_extent_delay_real
Git-commit: 1bfd7618cbf2de630c845f60f5370671c2cd1c5d
Patch-mainline: v4.15-rc1
References: bsc#1095344

Two cases in xfs_bmap_add_extent_delay_real currently insert a new
extent before updating the existing one that is being split.  While
this works fine with a simple extent list, a more complex tree can't
easily cope with overlapping extent.  Reshuffle the code a bit to update
the slot of the existing delalloc extent to the new real extent before
inserting the shortened delalloc extent before or after it.  This
avoids the overlapping extents while still allowing to update the
br_startblock field of the delalloc extent with the updated indirect
block reservation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/xfs/libxfs/xfs_bmap.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 74f5e3b89173..9fef6525c183 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -1807,7 +1807,7 @@ xfs_bmap_add_extent_delay_real(
 		 * Filling in the first part of a previous delayed allocation.
 		 * The left neighbor is not contiguous.
 		 */
-		xfs_iext_insert(bma->ip, bma->idx, 1, new, state);
+		xfs_iext_update_extent(bma->ip, state, bma->idx, new);
 		(*nextents)++;
 		if (bma->cur == NULL)
 			rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
@@ -1840,7 +1840,7 @@ xfs_bmap_add_extent_delay_real(
 		PREV.br_startoff = new_endoff;
 		PREV.br_blockcount = temp;
 		PREV.br_startblock = nullstartblock(da_new);
-		xfs_iext_update_extent(bma->ip, state, bma->idx + 1, &PREV);
+		xfs_iext_insert(bma->ip, bma->idx + 1, 1, &PREV, state);
 		break;
 
 	case BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG:
@@ -1883,7 +1883,7 @@ xfs_bmap_add_extent_delay_real(
 		 * Filling in the last part of a previous delayed allocation.
 		 * The right neighbor is not contiguous.
 		 */
-		xfs_iext_insert(bma->ip, bma->idx + 1, 1, new, state);
+		xfs_iext_update_extent(bma->ip, state, bma->idx, new);
 		(*nextents)++;
 		if (bma->cur == NULL)
 			rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
@@ -1915,7 +1915,7 @@ xfs_bmap_add_extent_delay_real(
 
 		PREV.br_startblock = nullstartblock(da_new);
 		PREV.br_blockcount = temp;
-		xfs_iext_update_extent(bma->ip, state, bma->idx, &PREV);
+		xfs_iext_insert(bma->ip, bma->idx, 1, &PREV, state);
 
 		bma->idx++;
 		break;
-- 
2.7.4