btrfs: enhance superblock checks
The superblock checksum is not verified upon mount. <awkward silence>
Add that check and also reorder existing checks to a more logical
order.
Current mkfs.btrfs does not calculate the correct checksum of
super_block and thus a freshly created filesytem will fail to mount when
this patch is applied.
First transaction commit calculates correct superblock checksum and
saves it to disk.
Reproducer:
$ mfks.btrfs /dev/sda
$ mount /dev/sda /mnt
$ btrfs scrub start /mnt
$ sleep 5
$ btrfs scrub status /mnt
... super:2 ...
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 78b9d45..63c328a 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2793,8 +2793,10 @@
static inline int btrfs_super_csum_size(struct btrfs_super_block *s)
{
- int t = btrfs_super_csum_type(s);
- BUG_ON(t >= ARRAY_SIZE(btrfs_csum_sizes));
+ u16 t = btrfs_super_csum_type(s);
+ /*
+ * csum type is validated at mount time
+ */
return btrfs_csum_sizes[t];
}