linux-stable.git/drivers/md/raid5.c, branch v4.5

MD: rename some functions

2016-01-20T21:52:20+00:00

These short function names are hard to search. Rename them to make vim happy.

Signed-off-by: Shaohua Li

raid5-cache: add journal hot add/remove support

2016-01-06T00:39:57+00:00

Add support for journal disk hot add/remove. Mostly trival checks in md
part. The raid5 part is a little tricky. For hot-remove, we can't wait
pending write as it's called from raid5d. The wait will cause deadlock.
We simplily fail the hot-remove. A hot-remove retry can success
eventually since if journal disk is faulty all pending write will be
failed and finish. For hot-add, since an array supporting journal but
without journal disk will be marked read-only, we are safe to hot add
journal without stopping IO (should be read IO, while journal only
handles write IO).

Signed-off-by: Shaohua Li 
Signed-off-by: NeilBrown

md/raid5: remove redundant check in stripe_add_to_batch_list()

2016-01-06T00:38:22+00:00

The stripe_add_to_batch_list() function is called only if
stripe_can_batch() returned true, so there is no need for double check.

Signed-off-by: Roman Gushchin 
Cc: Neil Brown 
Cc: linux-raid@vger.kernel.org
Signed-off-by: NeilBrown

Merge tag 'md/4.4' of git://neil.brown.name/md

2015-11-05T05:12:47+00:00

Pull md updates from Neil Brown:
 "Two major components to this update.

   1) The clustered-raid1 support from SUSE is nearly complete.  There
      are a few outstanding issues being worked on.  Maybe half a dozen
      patches will bring this to a usable state.

   2) The first stage of journalled-raid5 support from Facebook makes an
      appearance.  With a journal device configured (typically NVRAM or
      SSD), the "RAID5 write hole" should be closed - a crash during
      degraded operations cannot result in data corruption.

      The next stage will be to use the journal as a write-behind cache
      so that latency can be reduced and in some cases throughput
      increased by performing more full-stripe writes.

* tag 'md/4.4' of git://neil.brown.name/md: (66 commits)
  MD: when RAID journal is missing/faulty, block RESTART_ARRAY_RW
  MD: set journal disk ->raid_disk
  MD: kick out journal disk if it's not fresh
  raid5-cache: start raid5 readonly if journal is missing
  MD: add new bit to indicate raid array with journal
  raid5-cache: IO error handling
  raid5: journal disk can't be removed
  raid5-cache: add trim support for log
  MD: fix info output for journal disk
  raid5-cache: use bio chaining
  raid5-cache: small log->seq cleanup
  raid5-cache: new helper: r5_reserve_log_entry
  raid5-cache: inline r5l_alloc_io_unit into r5l_new_meta
  raid5-cache: take rdev->data_offset into account early on
  raid5-cache: refactor bio allocation
  raid5-cache: clean up r5l_get_meta
  raid5-cache: simplify state machine when caches flushes are not needed
  raid5-cache: factor out a helper to run all stripes for an I/O unit
  raid5-cache: rename flushed_ios to finished_ios
  raid5-cache: free I/O units earlier
  ...

MD: set journal disk ->raid_disk

2015-11-01T02:48:29+00:00

Set journal disk ->raid_disk to >=0, I choose raid_disks + 1 instead of
0, because we already have a disk with ->raid_disk 0 and this causes
sysfs entry creation conflict. A lot of places assumes disk with
->raid_disk >=0 is normal raid disk, so we add check for journal disk.

Signed-off-by: Shaohua Li 
Signed-off-by: NeilBrown

raid5-cache: start raid5 readonly if journal is missing

2015-11-01T02:48:29+00:00

If raid array is expected to have journal (eg, journal is set in MD
superblock feature map) and the array is started without journal disk,
start the array readonly.

Signed-off-by: Shaohua Li 
Signed-off-by: NeilBrown

raid5-cache: IO error handling

2015-11-01T02:48:29+00:00

There are 3 places the raid5-cache dispatches IO. The discard IO error
doesn't matter, so we ignore it. The superblock write IO error can be
handled in MD core. The remaining are log write and flush. When the IO
error happens, we mark log disk faulty and fail all write IO. Read IO is
still allowed to run. Userspace will get a notification too and
corresponding daemon can choose setting raid array readonly for example.

Signed-off-by: Shaohua Li 
Signed-off-by: NeilBrown

raid5: journal disk can't be removed

2015-11-01T02:48:29+00:00

raid5-cache uses journal disk rdev->bdev, rdev->mddev in several places.
Don't allow journal disk disappear magically. On the other hand, we do
need to update superblock for other disks to bump up ->events, so next
time journal disk will be identified as stale.

Signed-off-by: Shaohua Li 
Signed-off-by: NeilBrown

raid5-cache: move reclaim stop to quiesce

2015-11-01T02:48:27+00:00

Move reclaim stop to quiesce handling, where is safer for this stuff.

Signed-off-by: Shaohua Li 
Signed-off-by: NeilBrown

raid5-cache: optimize FLUSH IO with log enabled

2015-11-01T02:48:26+00:00

With log enabled, bio is written to raid disks after the bio is settled
down in log disk. The recovery guarantees we can recovery the bio data
from log disk, so we we skip FLUSH IO.

Signed-off-by: Shaohua Li 
Signed-off-by: NeilBrown