linux-stable.git/drivers/md/raid1.c, branch v3.3

md/raid1: fix buglet in md_raid1_contested.

2012-02-13T03:24:05+00:00

Since we added 'replacement' capability, RAID1 can have twice
as many devices as ->raid_disks indicates.
So md_raid1_congested needs to check that many possible devices,
not just ->raid_disks many.

Signed-off-by: NeilBrown

md/raid1: perform bad-block tests for WriteMostly devices too.

2012-01-10T21:35:17+00:00

We normally try to avoid reading from write-mostly devices, but when
we do we really have to check for bad blocks and be sure not to
try reading them.

With the current code, best_good_sectors might not get set and that
causes zero-length read requests to be send down which is very
confusing.

This bug was introduced in commit d2eb35acfdccbe2 and so the patch
is suitable for 3.1.x and 3.2.x

Reported-and-tested-by: Michał Mirosław 
Reported-and-tested-by: Art -kwaak- van Breemen 
Signed-off-by: NeilBrown 
Cc: stable@vger.kernel.org

md/raid1: Mark device want_replacement when we see a write error.

2011-12-22T23:17:57+00:00

Now that WantReplacement drives are replaced cleanly, mark a drive
as want_replacement when we see a write error.  It might get failed soon so
the WantReplacement flag is irrelevant, but if the write error is recorded
in the bad block log, we still want to activate any spare that might
be available.

Signed-off-by:  NeilBrown

md/raid1: If there is a spare and a want_replacement device, start replacement.

2011-12-22T23:17:57+00:00

When attempting to add a spare to a RAID1 array, also consider
adding it as a replacement for a want_replacement device.

Signed-off-by: NeilBrown

md/raid1: recognise replacements when assembling arrays.

2011-12-22T23:17:57+00:00

If a Replacement is seen, file it as such.

If we see two replacements (or two normal devices) for the one slot,
abort.

Signed-off-by: NeilBrown

md/raid1: handle activation of replacement device when recovery completes.

2011-12-22T23:17:57+00:00

When recovery completes ->spare_active is called.
This checks if the replacement is ready and if so it fails
the original.

Signed-off-by: NeilBrown

md/raid1: Allow a failed replacement device to be removed.

2011-12-22T23:17:56+00:00

Replacement devices are stored at a different offset, so look
there too.

Signed-off-by: NeilBrown

md/raid1: Allocate spare to store replacement devices and their bios.

2011-12-22T23:17:56+00:00

In RAID1, a replacement is much like a normal device, so we just
double the size of the relevant arrays and look at all possible
devices for reads and writes.

This means that the array looks like it is now double the size in some
way - we need to be careful about that.
In particular, we checking if the array is still degraded while
creating a recovery request we need to only consider the first 'half'
- i.e. the real (non-replacement) devices.

Signed-off-by: NeilBrown

md/raid1: Replace use of mddev->raid_disks with conf->raid_disks.

2011-12-22T23:17:56+00:00

In general mddev->raid_disks can change unexpectedly while
conf->raid_disks will only change in a very controlled way.  So change
some uses of one to the other.

The use of mddev->raid_disks will not cause actually problems but
this way is more consistent and safer in the long term.

Signed-off-by: NeilBrown

md: change hot_remove_disk to take an rdev rather than a number.

2011-12-22T23:17:51+00:00

Soon an array will be able to have multiple devices with the
same raid_disk number (an original and a replacement).  So removing
a device based on the number won't work.  So pass the actual device
handle instead.

Reviewed-by: Dan Williams 
Signed-off-by: NeilBrown