Patch "Btrfs: bail out gracefully rather than BUG_ON" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

Btrfs: bail out gracefully rather than BUG_ON

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
btrfs-bail-out-gracefully-rather-than-bug_on.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Liu Bo <[email protected]>
Date: Mon, 30 Oct 2017 11:14:38 -0600
Subject: Btrfs: bail out gracefully rather than BUG_ON

From: Liu Bo <[email protected]>

[ 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.

---
 fs/btrfs/inode.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

@@ -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);

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/btrfs-bail-out-gracefully-rather-than-bug_on.patch queue-4.14/btrfs-fix-deadlock-when-writing-out-space-cache.patch queue-4.14/btrfs-fix-list_add-corruption-and-soft-lockups-in-fsync.patch