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%3Ba=su...

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 stable@vger.kernel.org know about it.

From foo@baz Thu Feb 1 13:45:42 CET 2018

From: Liu Bo bo.li.liu@oracle.com Date: Mon, 30 Oct 2017 11:14:38 -0600 Subject: Btrfs: bail out gracefully rather than BUG_ON

From: Liu Bo bo.li.liu@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.liu@oracle.com Reported-by: Guillaume Bouchard bouchard@mercs-eng.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@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);

Patches currently in stable-queue which might be from bo.li.liu@oracle.com 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