md/raid10: fix bug when raid10 recovery fails to recover a block.

commit e8b849158508565e0cd6bc80061124afc5879160 upstream.

commit e875ecea266a543e643b19e44cf472f1412708f9
    md/raid10 record bad blocks as needed during recovery.

added code to the "cannot recover this block" path to record a bad
block rather than fail the whole recovery.
Unfortunately this new case was placed *after* r10bio was freed rather
than *before*, yet it still uses r10bio.
This is will crash with a null dereference.

So move the freeing of r10bio down where it is safe.

Change-Id: I7ed133be8e1a07509fc97d168e6669652cca487b
Fixes: e875ecea266a543e643b19e44cf472f1412708f9
Reported-by: Damian Nowak <spam@nowaker.net>
URL: https://bugzilla.kernel.org/show_bug.cgi?id=68181
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
md/raid10: fix two bugs in handling of known-bad-blocks.

commit b50c259e25d9260b9108dc0c2964c26e5ecbe1c1 upstream.

If we discover a bad block when reading we split the request and
potentially read some of it from a different device.

The code path of this has two bugs in RAID10.
1/ we get a spin_lock with _irq, but unlock without _irq!!
2/ The calculation of 'sectors_handled' is wrong, as can be clearly
   seen by comparison with raid1.c

This leads to at least 2 warnings and a probable crash is a RAID10
ever had known bad blocks.

Change-Id: Ied2a1226f71988a34469912cddba04c488165947
Fixes: 856e08e23762dfb92ffc68fd0a8d228f9e152160
Reported-by: Damian Nowak <spam@nowaker.net>
URL: https://bugzilla.kernel.org/show_bug.cgi?id=68181
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux 3.4.78

Change-Id: Ib2537d42a31ee1362134d8748b12fafa829948e4