4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Liu Bo bo.li.liu@oracle.com
commit 6fb37b756acce6d6e045f79c3764206033f617b4 upstream.
With btrfs-corrupt-block, one can drop one chunk item and mounting will end up with a panic in btrfs_full_stripe_len().
This doesn't not remove the BUG_ON, but instead checks it a bit earlier when we find the block group item.
Signed-off-by: Liu Bo bo.li.liu@oracle.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/extent-tree.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-)
--- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -9502,7 +9502,22 @@ static int find_first_block_group(struct
if (found_key.objectid >= key->objectid && found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) { - ret = 0; + struct extent_map_tree *em_tree; + struct extent_map *em; + + em_tree = &root->fs_info->mapping_tree.map_tree; + read_lock(&em_tree->lock); + em = lookup_extent_mapping(em_tree, found_key.objectid, + found_key.offset); + read_unlock(&em_tree->lock); + if (!em) { + btrfs_err(root->fs_info, + "logical %llu len %llu found bg but no related chunk", + found_key.objectid, found_key.offset); + ret = -ENOENT; + } else { + ret = 0; + } goto out; } path->slots[0]++;