linux.git/drivers/md/raid1.c, branch v2.6.37

md/raid1: really fix recovery looping when single good device fails.

2010-11-24T05:39:46+00:00

Commit 4044ba58dd15cb01797c4fd034f39ef4a75f7cc3 supposedly fixed a
problem where if a raid1 with just one good device gets a read-error
during recovery, the recovery would abort and immediately restart in
an infinite loop.

However it depended on raid1_remove_disk removing the spare device
from the array.  But that does not happen in this case.  So add a test
so that in the 'recovery_disabled' case, the device will be removed.

This suitable for any kernel since 2.6.29 which is when
recovery_disabled was introduced.

Cc: stable@kernel.org
Reported-by: Sebastian Färber 
Signed-off-by: NeilBrown

md: tidy up device searches in read_balance.

2010-10-29T05:40:33+00:00

The code for searching through the device list to read-balance in
raid1 is rather clumsy and hard to follow.  Try to simplify it a bit.

No important functionality change here.


Signed-off-by: NeilBrown

md/raid1: fix some typos in comments.

2010-10-29T05:40:33+00:00

Signed-off-by: NeilBrown

md/raid1: discard unused variable.

2010-10-29T05:40:33+00:00

This structure field (flushing_bio_list) is never used, so remove it.

Signed-off-by: NeilBrown

md: use separate bio pool for each md device.

2010-10-28T06:36:15+00:00

bio_clone and bio_alloc allocate from a common bio pool.
If an md device is stacked with other devices that use this pool, or under
something like swap which uses the pool, then the multiple calls on
the pool can cause deadlocks.

So allocate a local bio pool for each md array and use that rather
than the common pool.

This pool is used both for regular IO and metadata updates.

Signed-off-by: NeilBrown

md: change type of first arg to sync_page_io.

2010-10-28T06:36:11+00:00

Currently sync_page_io takes a 'bdev'.
Every caller passes 'rdev->bdev'.
We will soon want another field out of the rdev in sync_page_io,
So just pass the rdev instead of the bdev out of it.

Signed-off-by: NeilBrown

md/raid1: perform mem allocation before disabling writes during resync.

2010-10-28T06:36:09+00:00

Though this mem alloc is GFP_NOIO an so will not deadlock, it seems
better to do the allocation before 'raise_barrier' which stops any IO
requests while the resync proceeds.

raid10 always uses this order, so it is at least consistent to do the
same in raid1.

Signed-off-by: NeilBrown

md: use bio_kmalloc rather than bio_alloc when failure is acceptable.

2010-10-28T06:36:06+00:00

bio_alloc can never fail (as it uses a mempool) but an block
indefinitely, especially if the caller is holding a reference to a
previously allocated bio.

So these to places which both handle failure and hold multiple bios
should not use bio_alloc, they should use bio_kmalloc.

Signed-off-by: NeilBrown

md: Fix possible deadlock with multiple mempool allocations.

2010-10-28T06:34:07+00:00

It is not safe to allocate from a mempool while holding an item
previously allocated from that mempool as that can deadlock when the
mempool is close to exhaustion.

So don't use a bio list to collect the bios to write to multiple
devices in raid1 and raid10.
Instead queue each bio as it becomes available so an unplug will
activate all previously allocated bios and so a new bio has a chance
of being allocated.

This means we must set the 'remaining' count to '1' before submitting
any requests, then when all are submitted, decrement 'remaining' and
possible handle the write completion at that point.

Reported-by: Torsten Kaiser 
Tested-by: Torsten Kaiser 
Signed-off-by: NeilBrown

md: use sector_t in bitmap_get_counter

2010-10-28T06:32:26+00:00

bitmap_get_counter returns the number of sectors covered
by the counter in a pass-by-reference variable.
In some cases this can be very large, so make it a sector_t
for safety.

Signed-off-by: NeilBrown