4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Liu Bo <bo.li....@oracle.com>


[ Upstream commit 56a0e706fcf870270878d6d72b71092ae42d229c ]

If a file's DIR_ITEM key is invalid (due to memory errors) and gets
written to disk, a future lookup_path can end up with kernel panic due
to BUG_ON().

This gets rid of the BUG_ON(), meanwhile output the corrupted key and
return ENOENT if it's invalid.

Signed-off-by: Liu Bo <bo.li....@oracle.com>
Reported-by: Guillaume Bouchard <bouch...@mercs-eng.com>
Signed-off-by: David Sterba <dste...@suse.com>
Signed-off-by: Sasha Levin <alexander.le...@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 fs/btrfs/inode.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5500,6 +5500,14 @@ static int btrfs_inode_by_name(struct in
                goto out_err;
 
        btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
+       if (location->type != BTRFS_INODE_ITEM_KEY &&
+           location->type != BTRFS_ROOT_ITEM_KEY) {
+               btrfs_warn(root->fs_info,
+"%s gets something invalid in DIR_ITEM (name %s, directory ino %llu, 
location(%llu %u %llu))",
+                          __func__, name, btrfs_ino(BTRFS_I(dir)),
+                          location->objectid, location->type, 
location->offset);
+               goto out_err;
+       }
 out:
        btrfs_free_path(path);
        return ret;
@@ -5816,8 +5824,6 @@ struct inode *btrfs_lookup_dentry(struct
                return inode;
        }
 
-       BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
-
        index = srcu_read_lock(&fs_info->subvol_srcu);
        ret = fixup_tree_root_location(fs_info, dir, dentry,
                                       &location, &sub_root);


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