Btrfs: do not defrag a file partially

xfstests 218 complains that btrfs defrags a file partially:
 After: 1
 Write backwards sync, but contiguous - should defrag to 1 extent
 Before: 10
-After: 1
+After: 2

To fix this, we need to set max_to_defrag count properly.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 6834be4c8709568e1f44fa8d42584a10228cdc07..0b06a5ca8afc5826ea87257024d35f1ae2e8aa32 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1066,7 +1066,7 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
                i = range->start >> PAGE_CACHE_SHIFT;
        }
        if (!max_to_defrag)
-               max_to_defrag = last_index;
+               max_to_defrag = last_index + 1;
 
        /*
         * make writeback starts from i, so the defrag range can be