btrfs-progs: check, fix csum check in the presence of non-inlined refs

When we have non-inlined extent references, we were failing to find the
corresponding extent item for an existing csum item in the csum tree.

Reproducer:

   mkfs.btrfs -f /dev/sdd
   mount /dev/sdd /mnt

   xfs_io -f -c "falloc 780366 135302" /mnt/foo
   xfs_io -c "falloc 327680 151552" /mnt/foo
   xfs_io -c "pwrite -S 0xff -b 131072 0 131072" /mnt/foo
   sync

   for i in `seq 1 40`; do btrfs subvolume snapshot /mnt /mnt/snap$i ; done
   umount /mnt

   btrfs check /dev/sdd

The check command exited with status 1 and the following output:

   Checking filesystem on /dev/sdd
   UUID: 2416ab5f-9d71-457e-bb13-a27d4f6b399a
   checking extents
   checking free space cache
   checking fs roots
   checking csums
   There are no extents for csum range 12980224-12984320
   Csum exists for 12980224-12984320 but there is no extent record
   found 1388544 bytes used err is 1
   total csum bytes: 132
   total tree bytes: 704512
   total fs tree bytes: 573440
   total extent tree bytes: 16384
   btree space waste bytes: 564479
   file data blocks allocated: 19341312
    referenced 14606336
   Btrfs v3.14.1-94-g80597e7

After this change it no longer erroneously reports a missing extent for the
csum item and exits with a status of 0.

Also added missing btrfs_prev_leaf() return value checks, as we were ignoring
errors and non-existence of left siblings completely.

Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.cz>

0 files changed, 0 insertions, 0 deletions