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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>
wifi-calibration
Josef Bacik 2013-04-23 10:53:18 -04:00
parent 79fb65a1f6
commit fb7669b5a0
1 changed files with 18 additions and 2 deletions
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20
fs/btrfs/volumes.c
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@ -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;