linux.git/drivers/md/multipath.c, branch v2.6.27

md: Make mddev->array_size sector-based.

2008-07-21T07:05:22+00:00

This patch renames the array_size field of struct mddev_s to array_sectors
and converts all instances to use units of 512 byte sectors instead of 1k
blocks.

Signed-off-by: Andre Noll 
Signed-off-by: NeilBrown

rationalise return value for ->hot_add_disk method.

2008-06-27T22:31:33+00:00

For all array types but linear, ->hot_add_disk returns 1 on
success, 0 on failure.
For linear, it returns 0 on success and -errno on failure.

This doesn't cause a functional problem because the ->hot_add_disk
function of linear is used quite differently to the others.
However it is confusing.

So convert all to return 0 for success or -errno on failure
and fix call sites to match.

Signed-off-by: Neil Brown

Support adding a spare to a live md array with external metadata.

2008-06-27T22:31:31+00:00

i.e. extend the 'md/dev-XXX/slot' attribute so that you can
tell a device to fill an vacant slot in an and md array.

Signed-off-by: Neil Brown

md: restart recovery cleanly after device failure.

2008-05-24T16:56:10+00:00

When we get any IO error during a recovery (rebuilding a spare), we abort
the recovery and restart it.

For RAID6 (and multi-drive RAID1) it may not be best to restart at the
beginning: when multiple failures can be tolerated, the recovery may be
able to continue and re-doing all that has already been done doesn't make
sense.

We already have the infrastructure to record where a recovery is up to
and restart from there, but it is not being used properly.
This is because:
  - We sometimes abort with MD_RECOVERY_ERR rather than just MD_RECOVERY_INTR,
    which causes the recovery not be be checkpointed.
  - We remove spares and then re-added them which loses important state
    information.

The distinction between MD_RECOVERY_ERR and MD_RECOVERY_INTR really isn't
needed.  If there is an error, the relevant drive will be marked as
Faulty, and that is enough to ensure correct handling of the error.  So we
first remove MD_RECOVERY_ERR, changing some of the uses of it to
MD_RECOVERY_INTR.

Then we cause the attempt to remove a non-faulty device from an array to
fail (unless recovery is impossible as the array is too degraded).  Then
when remove_and_add_spares attempts to remove the devices on which
recovery can continue, it will fail, they will remain in place, and
recovery will continue on them as desired.

Issue:  If we are halfway through rebuilding a spare and another drive
fails, and a new spare is immediately available,  do we want to:
 1/ complete the current rebuild, then go back and rebuild the new spare or
 2/ restart the rebuild from the start and rebuild both devices in
    parallel.

Both options can be argued for.  The code currently takes option 2 as
  a/ this requires least code change
  b/ this results in a minimally-degraded array in minimal time.

Cc: "Eivind Sarto" 
Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Remove blkdev warning triggered by using md

2008-05-15T02:11:15+00:00

As setting and clearing queue flags now requires that we hold a spinlock
on the queue, and as blk_queue_stack_limits is called without that lock,
get the lock inside blk_queue_stack_limits.

For blk_queue_stack_limits to be able to find the right lock, each md
personality needs to set q->queue_lock to point to the appropriate lock.
Those personalities which didn't previously use a spin_lock, us
q->__queue_lock.  So always initialise that lock when allocated.

With this in place, setting/clearing of the QUEUE_FLAG_PLUGGED bit will no
longer cause warnings as it will be clear that the proper lock is held.

Thanks to Dan Williams for review and fixing the silly bugs.

Signed-off-by: NeilBrown 
Cc: Dan Williams 
Cc: Jens Axboe 
Cc: Alistair John Strachan 
Cc: Nick Piggin 
Cc: "Rafael J. Wysocki" 
Cc: Jacek Luczak 
Cc: Prakash Punnoor 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

raid: remove leading TAB on printk messages

2008-04-28T15:58:42+00:00

MD drivers use one printk() call to print 2 log messages and the second line
may be prefixed by a TAB character.  It may also output a trailing space
before newline.  klogd (I think) turns the TAB character into the 2 characters
'^I' when logging to a file.  This looks ugly.

Instead of a leading TAB to indicate continuation, prefix both output lines
with 'raid:' or similar.  Also remove any trailing space in the vicinity of
the affected code and consistently end the sentences with a period.

Signed-off-by: Nick Andrew 
Cc: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

md: change ITERATE_RDEV to rdev_for_each

2008-02-06T18:41:19+00:00

As this is more in line with common practice in the kernel.  Also swap the
args around to be more like list_for_each.

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Add UNPLUG traces to all appropriate places

2007-11-09T12:41:32+00:00

Added blk_unplug interface, allowing all invocations of unplugs to result
in a generated blktrace UNPLUG.

Signed-off-by: Alan D. Brunelle 
Signed-off-by: Jens Axboe

block: convert blkdev_issue_flush() to use empty barriers

2007-10-16T09:05:02+00:00

Then we can get rid of ->issue_flush_fn() and all the driver private
implementations of that.

Signed-off-by: Jens Axboe

Drop 'size' argument from bio_endio and bi_end_io

2007-10-10T07:25:57+00:00

As bi_end_io is only called once when the reqeust is complete,
the 'size' argument is now redundant.  Remove it.

Now there is no need for bio_endio to subtract the size completed
from bi_size.  So don't do that either.

While we are at it, change bi_end_io to return void.

Signed-off-by: Neil Brown 
Signed-off-by: Jens Axboe