linux-stable.git/drivers/md/raid1.h, branch linux-3.1.y

md/raid1: Handle write errors by updating badblock log.

2011-07-28T01:32:41+00:00

When we get a write error (in the data area, not in metadata),
update the badblock log rather than failing the whole device.

As the write may well be many blocks, we trying writing each
block individually and only log the ones which fail.

Signed-off-by: NeilBrown 
Reviewed-by: Namhyung Kim

md/raid1: store behind-write pages in bi_vecs.

2011-07-28T01:32:10+00:00

When performing write-behind we allocate pages to store the data
during write.
Previously we just keep a list of pages.  Now we keep a list of
bi_vec which includes offset and size.
This means that the r1bio has complete information to create a new
bio which will be needed for retrying after write errors.

Signed-off-by: NeilBrown 
Reviewed-by: Namhyung Kim

md/raid1: clear bad-block record when write succeeds.

2011-07-28T01:31:49+00:00

If we succeed in writing to a block that was recorded as
being bad, we clear the bad-block record.

This requires some delayed handling as the bad-block-list update has
to happen in process-context.

Signed-off-by: NeilBrown 
Reviewed-by: Namhyung Kim

md/raid1: avoid reading from known bad blocks.

2011-07-28T01:31:48+00:00

Now that we have a bad block list, we should not read from those
blocks.
There are several main parts to this:
  1/ read_balance needs to check for bad blocks, and return not only
     the chosen device, but also how many good blocks are available
     there.
  2/ fix_read_error needs to avoid trying to read from bad blocks.
  3/ read submission must be ready to issue multiple reads to
     different devices as different bad blocks on different devices
     could mean that a single large read cannot be served by any one
     device, but can still be served by the array.
     This requires keeping count of the number of outstanding requests
     per bio.  This count is stored in 'bi_phys_segments'
  4/ retrying a read needs to also be ready to submit a smaller read
     and queue another request for the rest.

This does not yet handle bad blocks when reading to perform resync,
recovery, or check.

'md_trim_bio' will also be used for RAID10, so put it in md.c and
export it.

Signed-off-by: NeilBrown

md: change managed of recovery_disabled.

2011-07-27T01:00:36+00:00

If we hit a read error while recovering a mirror, we want to abort the
recovery without necessarily failing the disk - as having a disk this
a read error is better than not having an array at all.

Currently this is managed with a per-array flag "recovery_disabled"
and is only implemented for RAID1.  For RAID10 we will need finer
grained control as we might want to disable recovery for individual
devices separately.

So push more of the decision making into the personality.
'recovery_disabled' is now a 'cookie' which is copied when the
personality want to disable recovery and is changed when a device is
added to the array as this is used as a trigger to 'try recovery
again'.

This will allow RAID10 to get the control that it needs.

Signed-off-by: NeilBrown

MD: raid1 changes to allow use by device mapper

2011-06-08T05:11:31+00:00

MD RAID1: Changes to allow RAID1 to be used by device-mapper (dm-raid.c)

Added the necessary congestion function and conditionalize calls requiring an
array 'queue' or 'gendisk'.

Signed-off-by: Jonathan Brassow 
Signed-off-by: NeilBrown

md/raid1: improve handling of pages allocated for write-behind.

2011-05-11T04:51:19+00:00

The current handling and freeing of these pages is a bit fragile.
We only keep the list of allocated pages in each bio, so we need to
still have a valid bio when freeing the pages, which is a bit clumsy.

So simply store the allocated page list in the r1_bio so it can easily
be found and freed when we are finished with the r1_bio.

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: implment REQ_FLUSH/FUA support

2010-09-10T10:35:38+00:00

This patch converts md to support REQ_FLUSH/FUA instead of now
deprecated REQ_HARDBARRIER.  In the core part (md.c), the following
changes are notable.

* Unlike REQ_HARDBARRIER, REQ_FLUSH/FUA don't interfere with
  processing of other requests and thus there is no reason to mark the
  queue congested while FLUSH/FUA is in progress.

* REQ_FLUSH/FUA failures are final and its users don't need retry
  logic.  Retry logic is removed.

* Preflush needs to be issued to all member devices but FUA writes can
  be handled the same way as other writes - their processing can be
  deferred to request_queue of member devices.  md_barrier_request()
  is renamed to md_flush_request() and simplified accordingly.

For linear, raid0 and multipath, the core changes are enough.  raid1,
5 and 10 need the following conversions.

* raid1: Handling of FLUSH/FUA bio's can simply be deferred to
  request_queues of member devices.  Barrier related logic removed.

* raid5: Queue draining logic dropped.  FUA bit is propagated through
  biodrain and stripe resconstruction such that all the updated parts
  of the stripe are written out with FUA writes if any of the dirtying
  writes was FUA.  preread_active_stripes handling in make_request()
  is updated as suggested by Neil Brown.

* raid10: FUA bit needs to be propagated to write clones.

linear, raid0, 1, 5 and 10 tested.

Signed-off-by: Tejun Heo 
Reviewed-by: Neil Brown 
Signed-off-by: Jens Axboe

md/raid1: add takeover support for raid5->raid1

2009-12-14T01:51:41+00:00

A 2-device raid5 array can now be converted to raid1.

Signed-off-by: NeilBrown