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: Josef Bacik <jbacik@fusionio.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index c8a315d..c1a2217 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4232,9 +4232,25 @@
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;