From: Darrick J. Wong <darrick.wong@oracle.com>
Date: Thu, 28 Jun 2018 20:11:57 +0000 (-0500)
Subject: xfs: btree lookup shouldn't ASSERT on empty btree nodes
X-Git-Tag: v4.18.0-rc0~23
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=0e64ec0d5f0d333500d7d2fcc4520943e87e6220;p=thirdparty%2Fxfsprogs-dev.git

xfs: btree lookup shouldn't ASSERT on empty btree nodes

Source kernel commit: eeee0d6a9bc93eaa211918c203fde263d44fa20e

If a btree lookup encounters an empty btree node or an empty btree leaf
on a multi-level btree, that's evidence of a corrupt on-disk btree.
Therefore, we should return -EFSCORRUPTED to the upper levels, not an
ASSERT failure.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
---

diff --git a/libxfs/xfs_btree.c b/libxfs/xfs_btree.c
index 2bd9dd359..d64cd2899 100644
--- a/libxfs/xfs_btree.c
+++ b/libxfs/xfs_btree.c
@@ -1892,7 +1892,12 @@ xfs_btree_lookup(
 			high = xfs_btree_get_numrecs(block);
 			if (!high) {
 				/* Block is empty, must be an empty leaf. */
-				ASSERT(level == 0 && cur->bc_nlevels == 1);
+				if (level != 0 || cur->bc_nlevels != 1) {
+					XFS_CORRUPTION_ERROR(__func__,
+							XFS_ERRLEVEL_LOW,
+							cur->bc_mp, block);
+					return -EFSCORRUPTED;
+				}
 
 				cur->bc_ptrs[0] = dir != XFS_LOOKUP_LE;
 				*stat = 0;