Btrfs: correctly get tree level in tree_backref_for_extent
authorFilipe Manana <fdmanana@suse.com>
Mon, 15 Dec 2014 16:04:42 +0000 (16:04 +0000)
committerChris Mason <clm@fb.com>
Fri, 2 Jan 2015 19:47:56 +0000 (14:47 -0500)
commita1317f455ab936a9447f17b08e3e874c27742870
tree4aabbd7f4cf9c51911936d015d87f160c2250d3f
parentc7cfb8a5405a34777d670f7a5441bb2c7ca9730f
Btrfs: correctly get tree level in tree_backref_for_extent

If we are using skinny metadata, the block's tree level is in the offset
of the key and not in a btrfs_tree_block_info structure following the
extent item (it doesn't exist). Therefore fix it.

Besides returning the correct level in the tree, this also prevents reading
past the leaf's end in the case where the extent item is the last item in
the leaf (eb) and it has only 1 inline reference - this is because
sizeof(struct btrfs_tree_block_info) is greater than
sizeof(struct btrfs_extent_inline_ref).

Got it while running a scrub which produced the following warning:

    BTRFS: checksum error at logical 42123264 on dev /dev/sde, sector 15840: metadata node (level 24) in tree 5

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
fs/btrfs/backref.c