From 7411055db5ce64f836aaffd422396af0075fdc99 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Tue, 23 Jan 2024 23:42:29 +0100 Subject: [PATCH] btrfs: handle chunk tree lookup error in btrfs_relocate_sys_chunks() The unhandled case in btrfs_relocate_sys_chunks() loop is a corruption, as it could be caused only by two impossible conditions: - at first the search key is set up to look for a chunk tree item, with offset -1, this is an inexact search and the key->offset will contain the correct offset upon a successful search, a valid chunk tree item cannot have an offset -1 - after first successful search, the found_key corresponds to a chunk item, the offset is decremented by 1 before the next loop, it's impossible to find a chunk item there due to alignment and size constraints Reviewed-by: Josef Bacik Reviewed-by: Anand Jain Signed-off-by: David Sterba --- fs/btrfs/volumes.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 224345658ea556..56b0b167e3867b 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -3391,7 +3391,17 @@ static int btrfs_relocate_sys_chunks(struct btrfs_fs_info *fs_info) mutex_unlock(&fs_info->reclaim_bgs_lock); goto error; } - BUG_ON(ret == 0); /* Corruption */ + if (ret == 0) { + /* + * On the first search we would find chunk tree with + * offset -1, which is not possible. On subsequent + * loops this would find an existing item on an invalid + * offset (one less than the previous one, wrong + * alignment and size). + */ + ret = -EUCLEAN; + goto error; + } ret = btrfs_previous_item(chunk_root, path, key.objectid, key.type);