There is a bug in raid56_recov() which doesn't properly repair data and
P case corruption:
/* Data and P*/
if (dest2 == nr_devs - 1)
return raid6_recov_datap(nr_devs, stripe_len, dest1, data);
Note that, dest1/2 is to indicate which slot has corruption.
For RAID6 cases:
[0, nr_devs - 2) is for data stripes,
@data_devs - 2 is for P,
@data_devs - 1 is for Q.
For above code, the comment is correct, but the check condition is
wrong, and leads to the only project, btrfs-fuse, to report raid6
recovery error for 2 devices missing case.
Fix it by using correct condition.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2755204480