linux.git/drivers/md/raid0.c, branch v2.6.37

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

block: unify flags for struct bio and struct request

2010-08-07T16:20:39+00:00

Remove the current bio flags and reuse the request flags for the bio, too.
This allows to more easily trace the type of I/O from the filesystem
down to the block driver.  There were two flags in the bio that were
missing in the requests:  BIO_RW_UNPLUG and BIO_RW_AHEAD.  Also I've
renamed two request flags that had a superflous RW in them.

Note that the flags are in bio.h despite having the REQ_ name - as
blkdev.h includes bio.h that is the only way to go for now.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

md: enable raid4->raid0 takeover

2010-06-24T03:34:57+00:00

Only level 5 with layout=PARITY_N can be taken over to raid0 now.
Lets allow level 4 either.

Signed-off-by: Maciej Trela 
Signed-off-by: NeilBrown

md: clear layout after ->raid0 takeover

2010-06-24T03:34:45+00:00

After takeover from raid5/10 -> raid0 mddev->layout is not cleared.

Signed-off-by: Maciej Trela 
Signed-off-by: NeilBrown

md: fix handling of array level takeover that re-arranges devices.

2010-06-24T03:33:24+00:00

Most array level changes leave the list of devices largely unchanged,
possibly causing one at the end to become redundant.
However conversions between RAID0 and RAID10 need to renumber
all devices (except 0).

This renumbering is currently being done in the ->run method when the
new personality takes over.  However this is too late as the common
code in md.c might already have invalidated some of the devices if
they had a ->raid_disk number that appeared to high.

Moving it into the ->takeover method is too early as the array is
still active at that time and wrong ->raid_disk numbers could cause
confusion.

So add a ->new_raid_disk field to mdk_rdev_s and use it to communicate
the new raid_disk number.
Now the common code knows exactly which devices need to be renumbered,
and which can be invalidated, and can do it all at a convenient time
when the array is suspend.
It can also update some symlinks in sysfs which previously were not be
updated correctly.

Reported-by: Maciej Trela 
Signed-off-by: NeilBrown

Merge commit '3ff195b011d7decf501a4d55aeed312731094796' into for-linus

2010-05-21T22:31:36+00:00

Conflicts:
	drivers/md/md.c

- Resolved conflict in md_update_sb
- Added extra 'NULL' arg to new instance of sysfs_get_dirent.

Signed-off-by: NeilBrown

md/raid0: tidy up printk messages.

2010-05-18T05:27:59+00:00

All messages now start
   md/raid0:md-device-name:

Signed-off-by: NeilBrown

md: pass mddev to make_request functions rather than request_queue

2010-05-18T05:27:55+00:00

We used to pass the personality make_request function direct
to the block layer so the first argument had to be a queue.
But now we have the intermediary md_make_request so it makes
at lot more sense to pass a struct mddev_s.
It makes it possible to have an mddev without its own queue too.

Signed-off-by: NeilBrown

md: move io accounting out of personalities into md_make_request

2010-05-18T05:27:52+00:00

While I generally prefer letting personalities do as much as possible,
given that we have a central md_make_request anyway we may as well use
it to simplify code.
Also this centralises knowledge of ->gendisk which will help later.

Signed-off-by: NeilBrown

md: Add support for Raid5->Raid0 and Raid10->Raid0 takeover

2010-05-18T05:27:48+00:00

Signed-off-by: Maciej Trela 
Signed-off-by: NeilBrown