xfs: set format back to extents if xfs_bmap_extents_to_btree

commit 2c4306f 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 <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Reviewed-by: Darrick J. Wong <[email protected]> Signed-off-by: Darrick J. Wong <[email protected]> Signed-off-by: Nobuhiro Iwamatsu (CIP) <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
penglezos · Jul 31, 2020 · 8a443ff · 8a443ff
1 parent 1f850ba
commit 8a443ff
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
@@ -761,12 +761,16 @@ 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;
 	}
 
 	if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
 		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 -ENOSPC;
 	}