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Commit fb7669b5 authored by Josef Bacik's avatar Josef Bacik
Browse files

Btrfs: don't BUG_ON() in btrfs_num_copies 



A user sent me a btrfs-image that was panicing because of some corruption.  This
is because we pass in a bogus value to btrfs_num_copies, and it panics.  Instead
just return 1.  We only call btrfs_num_copies to see if there are other copies
to try and read for things, so if we just return 1 it will make the callers exit
out with an appropriate error value.  Thanks,

Signed-off-by: default avatarJosef Bacik <jbacik@fusionio.com>
parent 79fb65a1

fs/btrfs/volumes.c

+18 −2
Original line number Diff line number Diff line
@@ -4232,9 +4232,25 @@ int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len) 
	read_lock(&em_tree->lock);

	em = lookup_extent_mapping(em_tree, logical, len);

	read_unlock(&em_tree->lock);

	BUG_ON(!em);



	BUG_ON(em->start > logical || em->start + em->len < logical);

	/*

	 * We could return errors for these cases, but that could get ugly and

	 * we'd probably do the same thing which is just not do anything else

	 * and exit, so return 1 so the callers don't try to use other copies.

	 */

	if (!em) {

		btrfs_emerg(fs_info, "No mapping for %Lu-%Lu\n", logical,

			    logical+len);

		return 1;

	}



	if (em->start > logical || em->start + em->len < logical) {

		btrfs_emerg(fs_info, "Invalid mapping for %Lu-%Lu, got "

			    "%Lu-%Lu\n", logical, logical+len, em->start,

			    em->start + em->len);

		return 1;

	}



	map = (struct map_lookup *)em->bdev;

	if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))

		ret = map->num_stripes;