[PATCH 4.5 117/128] Btrfs: remove BUG_ON()s in btrfs_map_block

Greg Kroah-Hartman
2016-06-06T14:37:30Z

From: Josef Bacik <jbacik@fb.com>

commit e042d1ec4417981dfe9331e47b76f17929bc2ffe upstream.

btrfs_map_block can go horribly wrong in the face of fs corruption, lets agree
to not be assholes and panic at any possible chance things are all fucked up.

Signed-off-by: Josef Bacik <jbacik@fb.com>
[ removed type casts ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/btrfs/volumes.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)

--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5289,7 +5289,15 @@ static int __btrfs_map_block(struct btrf
stripe_nr = div64_u64(stripe_nr, stripe_len);

stripe_offset = stripe_nr * stripe_len;
- BUG_ON(offset < stripe_offset);
+ if (offset < stripe_offset) {
+ btrfs_crit(fs_info, "stripe math has gone wrong, "
+ "stripe_offset=%llu, offset=%llu, start=%llu, "
+ "logical=%llu, stripe_len=%llu",
+ stripe_offset, offset, em->start, logical,
+ stripe_len);
+ free_extent_map(em);
+ return -EINVAL;
+ }

/* stripe_offset is the offset of this block in its stripe*/
stripe_offset = offset - stripe_offset;
@@ -5528,7 +5536,13 @@ static int __btrfs_map_block(struct btrf
&stripe_index);
mirror_num = stripe_index + 1;
}
- BUG_ON(stripe_index >= map->num_stripes);
+ if (stripe_index >= map->num_stripes) {
+ btrfs_crit(fs_info, "stripe index math went horribly wrong, "
+ "got stripe_index=%u, num_stripes=%u",
+ stripe_index, map->num_stripes);
+ ret = -EINVAL;
+ goto out;
+ }

num_alloc_stripes = num_stripes;
if (dev_replace_is_ongoing) {