xfs: evict CoW fork extents when performing finsert/fcollapse

When we perform an finsert/fcollapse operation, cancel all the CoW
extents for the affected file offset range so that they don't end up
pointing to the wrong blocks.

Reported-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index cd9a5400ba4fef2a75d5c24f3f626f5ad0211fae..bc6c6e10a9699f789b998035fde33973796f46fa 100644 (file)
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1459,7 +1459,19 @@ xfs_shift_file_space(
                return error;
 
        /*
-        * The extent shiting code works on extent granularity. So, if
+        * Clean out anything hanging around in the cow fork now that
+        * we've flushed all the dirty data out to disk to avoid having
+        * CoW extents at the wrong offsets.
+        */
+       if (xfs_is_reflink_inode(ip)) {
+               error = xfs_reflink_cancel_cow_range(ip, offset, NULLFILEOFF,
+                               true);
+               if (error)
+                       return error;
+       }
+
+       /*
+        * The extent shifting code works on extent granularity. So, if
         * stop_fsb is not the starting block of extent, we need to split
         * the extent at stop_fsb.
         */