btrfs: warn if extent buffer mapping crosses a page boundary in csum_tree_block

Since commit d2e174d5d3 ("btrfs: document extent mapping assumptions in
checksum") we have a comment in place why map_private_extent_buffer()
can't return 1 in the csum_tree_block() case.

Make this a bit more explicit and WARN_ON() in case this this assumption
breaks.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Johannes Thumshirn 2019-02-25 14:24:16 +01:00 committed by David Sterba
parent 2996e1f8bc
commit c53839fc32

View file

@ -285,7 +285,7 @@ static int csum_tree_block(struct extent_buffer *buf, u8 *result)
*/
err = map_private_extent_buffer(buf, offset, 32,
&kaddr, &map_start, &map_len);
if (err)
if (WARN_ON(err))
return err;
cur_len = min(len, map_len - (offset - map_start));
crc = btrfs_csum_data(kaddr + offset - map_start,