From: Eric Sandeen <sandeen@xxxxxxxxxx> commit 2c4306f719b083d17df2963bc761777576b8ad1b upstream. If xfs_bmap_extents_to_btree fails in a mode where we call xfs_iroot_realloc(-1) to de-allocate the root, set the format back to extents. Otherwise we can assume we can dereference ifp->if_broot based on the XFS_DINODE_FMT_BTREE format, and crash. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199423 Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> [iwamatsu: backported to 4.4.y] Signed-off-by: Nobuhiro Iwamatsu (CIP) <nobuhiro1.iwamatsu@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/xfs/libxfs/xfs_bmap.c | 2 ++ 1 file changed, 2 insertions(+) --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -793,6 +793,8 @@ xfs_bmap_extents_to_btree( *logflagsp = 0; if ((error = xfs_alloc_vextent(&args))) { xfs_iroot_realloc(ip, -1, whichfork); + ASSERT(ifp->if_broot == NULL); + XFS_IFORK_FMT_SET(ip, whichfork, XFS_DINODE_FMT_EXTENTS); xfs_btree_del_cursor(cur, XFS_BTREE_ERROR); return error; }
