Pull md bugfix from NeilBrown:
 "Single bugfix for raid1/raid10.

  Fixes a recently introduced deadlock."

* tag 'md-3.7-fixes' of git://neil.brown.name/md:
  md/raid1{,0}: fix deadlock in bitmap_unplug.

If the raid1 or raid10 unplug function gets called
from a make_request function (which is very possible) when
there are bios on the current->bio_list list, then it will not
be able to successfully call bitmap_unplug() and it could
need to submit more bios and wait for them to complete.
But they won't complete while current->bio_list is non-empty.

So detect that case and handle the unplugging off to another thread
just like we already do when called from within the scheduler.

RAID1 version of bug was introduced in 3.6, so that part of fix is
suitable for 3.6.y.  RAID10 part won't apply.

Cc: stable@vger.kernel.org
Reported-by: Torsten Kaiser <just.for.lkml@googlemail.com>
Reported-by: Peter Maloney <peter.maloney@brockmann-consult.de>
Signed-off-by: NeilBrown <neilb@suse.de>

Pull md fixes from NeilBrown:
 "Several bug fixes for md in 3.7:

   - raid5 discard has problems
   - raid10 replacement devices have problems
   - bad block lock seqlock usage has problems
   - dm-raid doesn't free everything"

* tag 'md-3.7-fixes' of git://neil.brown.name/md:
  md/raid10: decrement correct pending counter when writing to replacement.
  md/raid10: close race that lose writes lost when replacement completes.
  md/raid5: Make sure we clear R5_Discard when discard is finished.
  md/raid5: move resolving of reconstruct_state earlier in stripe_handle.
  md/raid5: round discard alignment up to power of 2.
  md: make sure everything is freed when dm-raid stops an array.
  md: Avoid write invalid address if read_seqretry returned true.
  md: Reassigned the parameters if read_seqretry returned true in func md_is_badblock.

Request based dm attempts to re-run the request queue off the
request completion path. If used with a driver that potentially does
end_io from its request_fn, we could deadlock trying to recurse
back into request dispatch. Fix this by punting the request queue
run to kblockd.

Tested to fix a quickly reproducible deadlock in such a scenario.

Cc: stable@kernel.org
Acked-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

When a write to a replacement device completes, we carefully
and correctly found the rdev that the write actually went to
and the blithely called rdev_dec_pending on the primary rdev,
even if this write was to the replacement.

This means that any writes to an array while a replacement
was ongoing would cause the nr_pending count for the primary
device to go negative, so it could never be removed.

This bug has been present since replacement was introduced in
3.3, so it is suitable for any -stable kernel since then.

Reported-by: "George Spelvin" <linux@horizon.com>
Cc: stable@vger.kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>

When a replacement operation completes there is a small window
when the original device is marked 'faulty' and the replacement
still looks like a replacement.  The faulty should be removed and
the replacement moved in place very quickly, bit it isn't instant.

So the code write out to the array must handle the possibility that
the only working device for some slot in the replacement - but it
doesn't.  If the primary device is faulty it just gives up.  This
can lead to corruption.

So make the code more robust: if either  the primary or the
replacement is present and working, write to them.  Only when
neither are present do we give up.

This bug has been present since replacement was introduced in
3.3, so it is suitable for any -stable kernel since then.

Reported-by: "George Spelvin" <linux@horizon.com>
Cc: stable@vger.kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>

commit 9e44476851e91c86c98eb92b9bc27fb801f89072
    MD: raid5 avoid unnecessary zero page for trim

change raid5 to clear R5_Discard when the complete request is
handled rather than when submitting the per-device discard request.
However it did not clear R5_Discard for the parity device.

This means that if the stripe_head was reused before it expired from
the cache, the setting would be wrong and a hang would result.

Also if the R5_Uptodate bit happens to be set, R5_Discard again
won't be cleared.  But R5_Uptodate really should be clear at this point.

So make sure R5_Discard is cleared in all cases, and clear
R5_Uptodate when a 'discard' completes.

Signed-off-by: NeilBrown <neilb@suse.de>

stripe_handle.

The chunk of code in stripe_handle which responds to a
*_result value in reconstruct_state is really the completion
of some processing that happened outside of handle_stripe
(possibly asynchronously) and so should be one of the first
things done in handle_stripe().

After the next patch it will be important that it happens before
handle_stripe_clean_event(), as that will clear some dev->flags
bit that this code tests.

Signed-off-by: NeilBrown <neilb@suse.de>

blkdev_issue_discard currently assumes that the granularity
is a power of 2.  So in raid5, round the chosen number up to
avoid embarrassment.

Cc: Shaohua Li <shli@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>

md_stop() would stop an array, but not free various attached
data structures.
For internal arrays, these are freed later in do_md_stop() or
mddev_put(), but they don't apply for dm-raid arrays.
So get md_stop() to free them, and only all it from dm-raid.
For internal arrays we now call __md_stop.

Reported-by: majianpeng <majianpeng@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>