Commit Graph

3651 Commits

Author SHA1 Message Date
Linus Torvalds
c91aa67eed A few fixes for md.
Most of these are related to the new "batched stripe writeout",
 but there are a few others.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2
 
 iQIVAwUAVVAgfznsnt1WYoG5AQKNsBAAw+yXVnRlLfzTPOhiIolvdmdmck6ghpV7
 eTHTbDEVkDo+a+caU01mhkHtL2wEuxGqr4XHTASIM9Xjn2YLhH14HOtBPl6+IddR
 F58X+SN8/pK4tzc5P42AAbfGfqeJSBPSl49L94+Pd9BsagNYZOUx7c/WK5lKay6O
 ZQRvI3Bafg7VTzHCw931sN11yY/PS+45zpOentk5TlavRPcZfuVTh1QzSyAUvbtN
 sAFK2+ISflj8+TW0rLo44c3kkC7ARFKcq5lJt4WsQUntJTjiIROvqvaEP+IUZkGr
 y+yvCJbskJ6B03XrcuvdkFrp3Qe0yWtHCN6qKhc8AI/c/pcuz24xTYQ6V6LDyAy8
 N2z6m1Kri97qxZpOONNh31WOCmVyFmwiz7+54soEeTDg3xgTb60UiZe8T+9ZcxoY
 sN8ksVSGGapgQUUGYcidbZla6uSWNjZq9hQgDJFUwG3HhvT3E/qiUT9kqAxfPsLE
 Vxw/KQ5GkW+7ldaPmGuv29hc3THjsiLY5Bx0kBlmgao3fcT61WbNcZPJOQfMxlT7
 6qoJSiNoq612TaHj3X06FXhMGE/fwjwjOO+PpULxM47giHcKrVR/qlG4kREYa2vj
 UgV05rP/S+k3Mce4dHzvUuE57t0ADff0d/mZvhfzERjNdwTMdWgia89XLg7D06rk
 UGB/o2IwWug=
 =tapF
 -----END PGP SIGNATURE-----

Merge tag 'md/4.1-rc3-fixes' of git://neil.brown.name/md

Pull md bugfixes from Neil Brown:
 "A few fixes for md.

  Most of these are related to the new "batched stripe writeout", but
  there are a few others"

* tag 'md/4.1-rc3-fixes' of git://neil.brown.name/md:
  md/raid5: fix handling of degraded stripes in batches.
  md/raid5: fix allocation of 'scribble' array.
  md/raid5: don't record new size if resize_stripes fails.
  md/raid5: avoid reading parity blocks for full-stripe write to degraded array
  md/raid5: more incorrect BUG_ON in handle_stripe_fill.
  md/raid5: new alloc_stripe() to allocate an initialize a stripe.
  md-raid0: conditional mddev->queue access to suit dm-raid
2015-05-11 10:33:31 -07:00
Linus Torvalds
5d5df5ee7c Two additional fixes for changes introduced via DM during the 4.1 merge
window: The first reverts a dm-crypt change that wasn't correct.  The
 second fixes a device format regression that impacted userspace.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 
 iQEcBAABAgAGBQJVTRZOAAoJEMUj8QotnQNaW7EIAJlHn+S8czm1Cb4gWBn7kg+X
 vzH5NIzr/SpDX8o3R8NBdrB8rgqTm4jQZrptbmgLG+j9XoaQupuFyNCiaAw47v2G
 P/WYlodNwTkb3I48XjwCRo00MtR3cEJ8ywNzvEJUvgPkgMMIzhieHsVT9L8bZv3n
 XDs8JzZyF966U0BeCjF4oDAazUrpEvWf0h4C5L47g8C0UQI7aGwYKoSvZm3DAImP
 awbJbnqtQuoRcI0HISHrjYi1vghgnmJY6aSx3tYSJPTNRkFNqgap7eZrUacicnOH
 bUVL3snBVebK3JMJhJXgfGW/FeeP9juhEY08JNTOZ5wa6BNuru0GHeqKuI3arHY=
 =jlAN
 -----END PGP SIGNATURE-----

Merge tag 'dm-4.1-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:
 "Two additional fixes for changes introduced via DM during the 4.1
  merge window.

  The first reverts a dm-crypt change that wasn't correct.  The second
  fixes a device format regression that impacted userspace"

* tag 'dm-4.1-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  init: fix regression by supporting devices with major:minor:offset format
  Revert "dm crypt: fix deadlock when async crypto algorithm returns -EBUSY"
2015-05-08 20:38:21 -07:00
Linus Torvalds
1daac193f2 Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
 "A collection of fixes since the merge window;

   - fix for a double elevator module release, from Chao Yu.  Ancient bug.

   - the splice() MORE flag fix from Christophe Leroy.

   - a fix for NVMe, fixing a patch that went in in the merge window.
     From Keith.

   - two fixes for blk-mq CPU hotplug handling, from Ming Lei.

   - bdi vs blockdev lifetime fix from Neil Brown, fixing and oops in md.

   - two blk-mq fixes from Shaohua, fixing a race on queue stop and a
     bad merge issue with FUA writes.

   - division-by-zero fix for writeback from Tejun.

   - a block bounce page accounting fix, making sure we inc/dec after
     bouncing so that pre/post IO pages match up.  From Wang YanQing"

* 'for-linus' of git://git.kernel.dk/linux-block:
  splice: sendfile() at once fails for big files
  blk-mq: don't lose requests if a stopped queue restarts
  blk-mq: fix FUA request hang
  block: destroy bdi before blockdev is unregistered.
  block:bounce: fix call inc_|dec_zone_page_state on different pages confuse value of NR_BOUNCE
  elevator: fix double release of elevator module
  writeback: use |1 instead of +1 to protect against div by zero
  blk-mq: fix CPU hotplug handling
  blk-mq: fix race between timeout and CPU hotplug
  NVMe: Fix VPD B0 max sectors translation
2015-05-08 19:49:35 -07:00
NeilBrown
bb27051f9f md/raid5: fix handling of degraded stripes in batches.
There is no need for special handling of stripe-batches when the array
is degraded.

There may be if there is a failure in the batch, but STRIPE_DEGRADED
does not imply an error.

So don't set STRIPE_BATCH_ERR in ops_run_io just because the array is
degraded.
This actually causes a bug: the STRIPE_DEGRADED flag gets cleared in
check_break_stripe_batch_list() and so the bitmap bit gets cleared
when it shouldn't.

So in check_break_stripe_batch_list(), split the batch up completely -
again STRIPE_DEGRADED isn't meaningful.

Also don't set STRIPE_BATCH_ERR when there is a write error to a
replacement device.  This simply removes the replacement device and
requires no extra handling.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-05-08 18:47:57 +10:00
NeilBrown
738a273806 md/raid5: fix allocation of 'scribble' array.
As the new 'scribble' array is sized based on chunk size,
we need to make sure the size matches the largest of 'old'
and 'new' chunk sizes when the array is undergoing reshape.

We also potentially need to resize it even when not resizing
the stripe cache, as chunk size can change without changing
number of devices.

So move the 'resize' code into a separate function, and
consider old and new sizes when allocating.

Signed-off-by: NeilBrown <neilb@suse.de>
Fixes: 46d5b78562 ("raid5: use flex_array for scribble data")
2015-05-08 18:47:48 +10:00
NeilBrown
6e9eac2dce md/raid5: don't record new size if resize_stripes fails.
If any memory allocation in resize_stripes fails we will return
-ENOMEM, but in some cases we update conf->pool_size anyway.

This means that if we try again, the allocations will be assumed
to be larger than they are, and badness results.

So only update pool_size if there is no error.

This bug was introduced in 2.6.17 and the patch is suitable for
-stable.

Fixes: ad01c9e375 ("[PATCH] md: Allow stripes to be expanded in preparation for expanding an array")
Cc: stable@vger.kernel.org (v2.6.17+)
Signed-off-by: NeilBrown <neilb@suse.de>
2015-05-08 18:47:35 +10:00
NeilBrown
10d82c5f0d md/raid5: avoid reading parity blocks for full-stripe write to degraded array
When performing a reconstruct write, we need to read all blocks
that are not being over-written .. except the parity (P and Q) blocks.

The code currently reads these (as they are not being over-written!)
unnecessarily.

Signed-off-by: NeilBrown <neilb@suse.de>
Fixes: ea664c8245 ("md/raid5: need_this_block: tidy/fix last condition.")
2015-05-08 18:47:17 +10:00
NeilBrown
b0c783b323 md/raid5: more incorrect BUG_ON in handle_stripe_fill.
It is not incorrect to call handle_stripe_fill() when
a batch of full-stripe writes is active.
It is, however, a BUG if fetch_block() then decides
it needs to actually fetch anything.

So move the 'BUG_ON' to where it belongs.

Signed-off-by: NeilBrown  <neilb@suse.de>
Fixes: 59fc630b8b ("RAID5: batch adjacent full stripe write")
2015-05-08 18:46:52 +10:00
NeilBrown
f18c1a35f6 md/raid5: new alloc_stripe() to allocate an initialize a stripe.
The new batch_lock and batch_list fields are being initialized in
grow_one_stripe() but not in resize_stripes().  This causes a crash
on resize.

So separate the core initialization into a new function and call it
from both allocation sites.

Signed-off-by: NeilBrown <neilb@suse.de>
Fixes: 59fc630b8b ("RAID5: batch adjacent full stripe write")
2015-05-08 18:40:01 +10:00
Heinz Mauelshagen
b6538fe329 md-raid0: conditional mddev->queue access to suit dm-raid
This patch is a prerequisite for dm-raid "raid0" support to allow
dm-raid to access the MD RAID0 personality doing unconditional
accesses to mddev->queue, which is NULL in case of dm-raid stacked on
top of MD.

Most of the conditional mddev->queue accesses made it to upstream but
this missing one, which prohibits md raid0 to set disk stack limits
(being done in dm core in case of md underneath dm).

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Tested-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-05-08 18:39:40 +10:00
Rabin Vincent
c0403ec0bb Revert "dm crypt: fix deadlock when async crypto algorithm returns -EBUSY"
This reverts Linux 4.1-rc1 commit 0618764cb2.

The problem which that commit attempts to fix actually lies in the
Freescale CAAM crypto driver not dm-crypt.

dm-crypt uses CRYPTO_TFM_REQ_MAY_BACKLOG.  This means the the crypto
driver should internally backlog requests which arrive when the queue is
full and process them later.  Until the crypto hw's queue becomes full,
the driver returns -EINPROGRESS.  When the crypto hw's queue if full,
the driver returns -EBUSY, and if CRYPTO_TFM_REQ_MAY_BACKLOG is set, is
expected to backlog the request and process it when the hardware has
queue space.  At the point when the driver takes the request from the
backlog and starts processing it, it calls the completion function with
a status of -EINPROGRESS.  The completion function is called (for a
second time, in the case of backlogged requests) with a status/err of 0
when a request is done.

Crypto drivers for hardware without hardware queueing use the helpers,
crypto_init_queue(), crypto_enqueue_request(), crypto_dequeue_request()
and crypto_get_backlog() helpers to implement this behaviour correctly,
while others implement this behaviour without these helpers (ccp, for
example).

dm-crypt (before the patch that needs reverting) uses this API
correctly.  It queues up as many requests as the hw queues will allow
(i.e. as long as it gets back -EINPROGRESS from the request function).
Then, when it sees at least one backlogged request (gets -EBUSY), it
waits till that backlogged request is handled (completion gets called
with -EINPROGRESS), and then continues.  The references to
af_alg_wait_for_completion() and af_alg_complete() in that commit's
commit message are irrelevant because those functions only handle one
request at a time, unlink dm-crypt.

The problem is that the Freescale CAAM driver, which that commit
describes as having being tested with, fails to implement the
backlogging behaviour correctly.  In cam_jr_enqueue(), if the hardware
queue is full, it simply returns -EBUSY without backlogging the request.
What the observed deadlock was is not described in the commit message
but it is obviously the wait_for_completion() in crypto_convert() where
dm-crypto would wait for the completion being called with -EINPROGRESS
in the case of backlogged requests.  This completion will never be
completed due to the bug in the CAAM driver.

Commit 0618764cb2 incorrectly made dm-crypt wait for every request,
even when the driver/hardware queues are not full, which means that
dm-crypt will never see -EBUSY.  This means that that commit will cause
a performance regression on all crypto drivers which implement the API
correctly.

Revert it.  Correct backlog handling should be implemented in the CAAM
driver instead.

Cc'ing stable purely because commit 0618764cb2 did.  If for some reason
a stable@ kernel did pick up commit 0618764cb2 it should get reverted.

Signed-off-by: Rabin Vincent <rabin.vincent@axis.com>
Reviewed-by: Horia Geanta <horia.geanta@freescale.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-05 12:16:43 -04:00
Mike Snitzer
aa6df8dd28 dm: fix free_rq_clone() NULL pointer when requeueing unmapped request
Commit 022333427a ("dm: optimize dm_mq_queue_rq to _not_ use kthread if
using pure blk-mq") mistakenly removed free_rq_clone()'s clone->q check
before testing clone->q->mq_ops.  It was an oversight to discontinue
that check for 1 of the 2 use-cases for free_rq_clone():
1) free_rq_clone() called when an unmapped original request is requeued
2) free_rq_clone() called in the request-based IO completion path

The clone->q check made sense for case  but not for .  However, we
cannot just reinstate the check as it'd mask a serious bug in the IO
completion case  -- no in-flight request should have an uninitialized
request_queue (basic block layer refcounting _should_ ensure this).

The NULL pointer seen for case  is detailed here:
https://www.redhat.com/archives/dm-devel/2015-April/msg00160.html

Fix this free_rq_clone() NULL pointer by simply checking if the
mapped_device's type is DM_TYPE_MQ_REQUEST_BASED (clone's queue is
blk-mq) rather than checking clone->q->mq_ops.  This avoids the need to
dereference clone->q, but a WARN_ON_ONCE is added to let us know if an
uninitialized clone request is being completed.

Reported-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-30 10:25:21 -04:00
Christoph Hellwig
3e6180f0c8 dm: only initialize the request_queue once
Commit bfebd1cdb4 ("dm: add full blk-mq support to request-based DM")
didn't properly account for the need to short-circuit re-initializing
DM's blk-mq request_queue if it was already initialized.

Otherwise, reloading a blk-mq request-based DM table (either manually
or via multipathd) resulted in errors, see:
 https://www.redhat.com/archives/dm-devel/2015-April/msg00132.html

Fix is to only initialize the request_queue on the initial table load
(when the mapped_device type is assigned).

This is better than having dm_init_request_based_blk_mq_queue() return
early if the queue was already initialized because it elevates the
constraint to a more meaningful location in DM core.  As such the
pre-existing early return in dm_init_request_based_queue() can now be
removed.

Fixes: bfebd1cdb4 ("dm: add full blk-mq support to request-based DM")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-30 10:25:21 -04:00
NeilBrown
6cd18e711d block: destroy bdi before blockdev is unregistered.
Because of the peculiar way that md devices are created (automatically
when the device node is opened), a new device can be created and
registered immediately after the
	blk_unregister_region(disk_devt(disk), disk->minors);
call in del_gendisk().

Therefore it is important that all visible artifacts of the previous
device are removed before this call.  In particular, the 'bdi'.

Since:
commit c4db59d31e
Author: Christoph Hellwig <hch@lst.de>
    fs: don't reassign dirty inodes to default_backing_dev_info

moved the
   device_unregister(bdi->dev);
call from bdi_unregister() to bdi_destroy() it has been quite easy to
lose a race and have a new (e.g.) "md127" be created after the
blk_unregister_region() call and before bdi_destroy() is ultimately
called by the final 'put_disk', which must come after del_gendisk().

The new device finds that the bdi name is already registered in sysfs
and complains

> [ 9627.630029] WARNING: CPU: 18 PID: 3330 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x5a/0x70()
> [ 9627.630032] sysfs: cannot create duplicate filename '/devices/virtual/bdi/9:127'

We can fix this by moving the bdi_destroy() call out of
blk_release_queue() (which can happen very late when a refcount
reaches zero) and into blk_cleanup_queue() - which happens exactly when the md
device driver calls it.

Then it is only necessary for md to call blk_cleanup_queue() before
del_gendisk().  As loop.c devices are also created on demand by
opening the device node, we make the same change there.

Fixes: c4db59d31e
Reported-by: Azat Khuzhin <a3at.mail@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org (v4.0)
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-04-27 10:27:20 -06:00
Linus Torvalds
474095e46c md updates for 4.1
Highlights:
 
 - "experimental" code for managing md/raid1 across a cluster using
   DLM.  Code is not ready for general use and triggers a WARNING if used.
   However it is looking good and mostly done and having in mainline
   will help co-ordinate development.
 - RAID5/6 can now batch multiple (4K wide) stripe_heads so as to
   handle a full (chunk wide) stripe as a single unit.
 - RAID6 can now perform read-modify-write cycles which should
   help performance on larger arrays: 6 or more devices.
 - RAID5/6 stripe cache now grows and shrinks dynamically.  The value
   set is used as a minimum.
 - Resync is now allowed to go a little faster than the 'mininum' when
   there is competing IO.  How much faster depends on the speed of the
   devices, so the effective minimum should scale with device speed to
   some extent.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2
 
 iQIVAwUAVTbIxDnsnt1WYoG5AQIgAA//Z9FlEpkHcJJ75WGjrXgGJPyNTfEZOkoz
 jnD8PpBY2Afp341vMatd0XKErdEAhuPQmJMAa+tbxht6pk77X3fSzXghGA8FEafg
 yazn5pfBt6NXmepV4vhl/+LNYuWRxxLSA9EDm7wEg+tiO0UEts+a0w2TSXzcT1w+
 30Yi1EjAlTaJ5yjlBHUOtTXWE43D6RKnUr6FMy2dRlnzlFyDlezRMChWo9v6OkQF
 YqJ20FcvmJdLHY/6Yif3jvpm7eQecMqdCZENTvW/mJI86zqf6E+ToCYS1VNjfDnK
 ud61iU9eshu4WtNWBG6KLuHBD0grO1NaEL7/S16w1KdNJMhYgiK8WussvIAJEesA
 5SlETM7Y/1XFq8puwlAq2/tuPfhZ+TFxnAwce/C3hMTDcYAACnS/R6INFQXqGvy3
 nX1NLogrCycX8oqxv3jTFKLVqIVwlkSlHcUGzIWjcfCF37StcXFKI5q862agyg2+
 NNocFMuXhPPM1YcB9JJSo2nCsor4e9tTdVEZlFm2B3cc8LJ9BLWUMSoi1h7VK/1g
 P7psnPIjz7/cdI2TZTFjGTZ0Kvhx/NTYp41AZealDNxeGWUNM+5xGZnUF8QRBc/E
 0dGHtEAah834BDQFvNnJtuuh/s+KwbvswjNP+njoBsHjIQIvngDABpOwpIkdqF6r
 diQ2gUPnHN0=
 =OHG6
 -----END PGP SIGNATURE-----

Merge tag 'md/4.1' of git://neil.brown.name/md

Pull md updates from Neil Brown:
 "More updates that usual this time.  A few have performance impacts
  which hould mostly be positive, but RAID5 (in particular) can be very
  work-load ensitive...  We'll have to wait and see.

  Highlights:

   - "experimental" code for managing md/raid1 across a cluster using
     DLM.  Code is not ready for general use and triggers a WARNING if
     used.  However it is looking good and mostly done and having in
     mainline will help co-ordinate development.

   - RAID5/6 can now batch multiple (4K wide) stripe_heads so as to
     handle a full (chunk wide) stripe as a single unit.

   - RAID6 can now perform read-modify-write cycles which should help
     performance on larger arrays: 6 or more devices.

   - RAID5/6 stripe cache now grows and shrinks dynamically.  The value
     set is used as a minimum.

   - Resync is now allowed to go a little faster than the 'mininum' when
     there is competing IO.  How much faster depends on the speed of the
     devices, so the effective minimum should scale with device speed to
     some extent"

* tag 'md/4.1' of git://neil.brown.name/md: (58 commits)
  md/raid5: don't do chunk aligned read on degraded array.
  md/raid5: allow the stripe_cache to grow and shrink.
  md/raid5: change ->inactive_blocked to a bit-flag.
  md/raid5: move max_nr_stripes management into grow_one_stripe and drop_one_stripe
  md/raid5: pass gfp_t arg to grow_one_stripe()
  md/raid5: introduce configuration option rmw_level
  md/raid5: activate raid6 rmw feature
  md/raid6 algorithms: xor_syndrome() for SSE2
  md/raid6 algorithms: xor_syndrome() for generic int
  md/raid6 algorithms: improve test program
  md/raid6 algorithms: delta syndrome functions
  raid5: handle expansion/resync case with stripe batching
  raid5: handle io error of batch list
  RAID5: batch adjacent full stripe write
  raid5: track overwrite disk count
  raid5: add a new flag to track if a stripe can be batched
  raid5: use flex_array for scribble data
  md raid0: access mddev->queue (request queue member) conditionally because it is not set when accessed from dm-raid
  md: allow resync to go faster when there is competing IO.
  md: remove 'go_faster' option from ->sync_request()
  ...
2015-04-24 09:28:01 -07:00
Eric Mei
9ffc8f7cb9 md/raid5: don't do chunk aligned read on degraded array.
When array is degraded, read data landed on failed drives will result in
reading rest of data in a stripe. So a single sequential read would
result in same data being read twice.

This patch is to avoid chunk aligned read for degraded array. The
downside is to involve stripe cache which means associated CPU overhead
and extra memory copy.

Test Results:
Following test are done on a enterprise storage node with Seagate 6T SAS
drives and Xeon E5-2648L CPU (10 cores, 1.9Ghz), 10 disks MD RAID6 8+2,
chunk size 128 KiB.

I use FIO, using direct-io with various bs size, enough queue depth,
tested sequential and 100% random read against 3 array config:
 1) optimal, as baseline;
 2) degraded;
 3) degraded with this patch.
Kernel version is 4.0-rc3.

Each individual test I only did once so there might be some variations,
but we just focus on big trend.

Sequential Read:
  bs=(KiB)  optimal(MiB/s)  degraded(MiB/s)  degraded-with-patch (MiB/s)
   1024       1608            656              995
    512       1624            710              956
    256       1635            728              980
    128       1636            771              983
     64       1612           1119             1000
     32       1580           1420             1004
     16       1368            688              986
      8        768            647              953
      4        411            413              850

Random Read:
  bs=(KiB)  optimal(IOPS)  degraded(IOPS)  degraded-with-patch (IOPS)
   1024        163            160              156
    512        274            273              272
    256        426            428              424
    128        576            592              591
     64        726            724              726
     32        849            848              837
     16        900            970              971
      8        927            940              929
      4        948            940              955

Some notes:
  * In sequential + optimal, as bs size getting smaller, the FIO thread
become CPU bound.
  * In sequential + degraded, there's big increase when bs is 64K and
32K, I don't have explanation.
  * In sequential + degraded-with-patch, the MD thread mostly become CPU
bound.

If you want to we can discuss specific data point in those data. But in
general it seems with this patch, we have more predictable and in most
cases significant better sequential read performance when array is
degraded, and almost no noticeable impact on random read.

Performance is a complicated thing, the patch works well for this
particular configuration, but may not be universal. For example I
imagine testing on all SSD array may have very different result. But I
personally think in most cases IO bandwidth is more scarce resource than
CPU.


Signed-off-by: Eric Mei <eric.mei@seagate.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 08:00:43 +10:00
NeilBrown
edbe83ab4c md/raid5: allow the stripe_cache to grow and shrink.
The default setting of 256 stripe_heads is probably
much too small for many configurations.  So it is best to make it
auto-configure.

Shrinking the cache under memory pressure is easy.  The only
interesting part here is that we put a fairly high cost
('seeks') on shrinking the cache as the cost is greater than
just having to read more data, it reduces parallelism.

Growing the cache on demand needs to be done carefully.  If we allow
fast growth, that can upset memory balance as lots of dirty memory can
quickly turn into lots of memory queued in the stripe_cache.
It is important for the raid5 block device to appear congested to
allow write-throttling to work.

So we only add stripes slowly. We set a flag when an allocation
fails because all stripes are in use, allocate at a convenient
time when that flag is set, and don't allow it to be set again
until at least one stripe_head has been released for re-use.

This means that a spurt of requests will only cause one stripe_head
to be allocated, but a steady stream of requests will slowly
increase the cache size - until memory pressure puts it back again.

It could take hours to reach a steady state.

The value written to, and displayed in, stripe_cache_size is
used as a minimum.  The cache can grow above this and shrink back
down to it.  The actual size is not directly visible, though it can
be deduced to some extent by watching stripe_cache_active.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 08:00:43 +10:00
NeilBrown
5423399a84 md/raid5: change ->inactive_blocked to a bit-flag.
This allows us to easily add more (atomic) flags.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 08:00:43 +10:00
NeilBrown
486f0644c3 md/raid5: move max_nr_stripes management into grow_one_stripe and drop_one_stripe
Rather than adjusting max_nr_stripes whenever {grow,drop}_one_stripe()
succeeds, do it inside the functions.

Also choose the correct hash to handle next inside the functions.

This removes duplication and will help with future new uses of
{grow,drop}_one_stripe.

This also fixes a minor bug where the "md/raid:%md: allocate XXkB"
message always said "0kB".

Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 08:00:42 +10:00
NeilBrown
a9683a795b md/raid5: pass gfp_t arg to grow_one_stripe()
This is needed for future improvement to stripe cache management.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 08:00:42 +10:00
Markus Stockhausen
d06f191f8e md/raid5: introduce configuration option rmw_level
Depending on the available coding we allow optimized rmw logic for write
operations. To support easier testing this patch allows manual control
of the rmw/rcw descision through the interface /sys/block/mdX/md/rmw_level.

The configuration can handle three levels of control.

rmw_level=0: Disable rmw for all RAID types. Hardware assisted P/Q
calculation has no implementation path yet to factor in/out chunks of
a syndrome. Enforcing this level can be benefical for slow CPUs with
hardware syndrome support and fast SSDs.

rmw_level=1: Estimate rmw IOs and rcw IOs. Execute rmw only if we will
save IOs. This equals the "old" unpatched behaviour and will be the
default.

rmw_level=2: Execute rmw even if calculated IOs for rmw and rcw are
equal. We might have higher CPU consumption because of calculating the
parity twice but it can be benefical otherwise. E.g. RAID4 with fast
dedicated parity disk/SSD. The option is implemented just to be
forward-looking and will ONLY work with this patch!

Signed-off-by: Markus Stockhausen <stockhausen@collogia.de>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 08:00:42 +10:00
Markus Stockhausen
584acdd49c md/raid5: activate raid6 rmw feature
Glue it altogehter. The raid6 rmw path should work the same as the
already existing raid5 logic. So emulate the prexor handling/flags
and split functions as needed.

1) Enable xor_syndrome() in the async layer.

2) Split ops_run_prexor() into RAID4/5 and RAID6 logic. Xor the syndrome
at the start of a rmw run as we did it before for the single parity.

3) Take care of rmw run in ops_run_reconstruct6(). Again process only
the changed pages to get syndrome back into sync.

4) Enhance set_syndrome_sources() to fill NULL pages if we are in a rmw
run. The lower layers will calculate start & end pages from that and
call the xor_syndrome() correspondingly.

5) Adapt the several places where we ignored Q handling up to now.

Performance numbers for a single E5630 system with a mix of 10 7200k
desktop/server disks. 300 seconds random write with 8 threads onto a
3,2TB (10*400GB) RAID6 64K chunk without spare (group_thread_cnt=4)

bsize   rmw_level=1   rmw_level=0   rmw_level=1   rmw_level=0
        skip_copy=1   skip_copy=1   skip_copy=0   skip_copy=0
   4K      115 KB/s      141 KB/s      165 KB/s      140 KB/s
   8K      225 KB/s      275 KB/s      324 KB/s      274 KB/s
  16K      434 KB/s      536 KB/s      640 KB/s      534 KB/s
  32K      751 KB/s    1,051 KB/s    1,234 KB/s    1,045 KB/s
  64K    1,339 KB/s    1,958 KB/s    2,282 KB/s    1,962 KB/s
 128K    2,673 KB/s    3,862 KB/s    4,113 KB/s    3,898 KB/s
 256K    7,685 KB/s    7,539 KB/s    7,557 KB/s    7,638 KB/s
 512K   19,556 KB/s   19,558 KB/s   19,652 KB/s   19,688 Kb/s

Signed-off-by: Markus Stockhausen <stockhausen@collogia.de>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 08:00:42 +10:00
shli@kernel.org
dabc4ec6ba raid5: handle expansion/resync case with stripe batching
expansion/resync can grab a stripe when the stripe is in batch list. Since all
stripes in batch list must be in the same state, we can't allow some stripes
run into expansion/resync. So we delay expansion/resync for stripe in batch
list.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 08:00:41 +10:00
shli@kernel.org
72ac733015 raid5: handle io error of batch list
If io error happens in any stripe of a batch list, the batch list will be
split, then normal process will run for the stripes in the list.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 08:00:41 +10:00
shli@kernel.org
59fc630b8b RAID5: batch adjacent full stripe write
stripe cache is 4k size. Even adjacent full stripe writes are handled in 4k
unit. Idealy we should use big size for adjacent full stripe writes. Bigger
stripe cache size means less stripes runing in the state machine so can reduce
cpu overhead. And also bigger size can cause bigger IO size dispatched to under
layer disks.

With below patch, we will automatically batch adjacent full stripe write
together. Such stripes will be added to the batch list. Only the first stripe
of the list will be put to handle_list and so run handle_stripe(). Some steps
of handle_stripe() are extended to cover all stripes of the list, including
ops_run_io, ops_run_biodrain and so on. With this patch, we have less stripes
running in handle_stripe() and we send IO of whole stripe list together to
increase IO size.

Stripes added to a batch list have some limitations. A batch list can only
include full stripe write and can't cross chunk boundary to make sure stripes
have the same parity disks. Stripes in a batch list must be in the same state
(no written, toread and so on). If a stripe is in a batch list, all new
read/write to add_stripe_bio will be blocked to overlap conflict till the batch
list is handled. The limitations will make sure stripes in a batch list be in
exactly the same state in the life circly.

I did test running 160k randwrite in a RAID5 array with 32k chunk size and 6
PCIe SSD. This patch improves around 30% performance and IO size to under layer
disk is exactly 32k. I also run a 4k randwrite test in the same array to make
sure the performance isn't changed with the patch.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 08:00:41 +10:00
shli@kernel.org
7a87f43405 raid5: track overwrite disk count
Track overwrite disk count, so we can know if a stripe is a full stripe write.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 08:00:41 +10:00
shli@kernel.org
da41ba6597 raid5: add a new flag to track if a stripe can be batched
A freshly new stripe with write request can be batched. Any time the stripe is
handled or new read is queued, the flag will be cleared.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 08:00:41 +10:00
shli@kernel.org
46d5b78562 raid5: use flex_array for scribble data
Use flex_array for scribble data. Next patch will batch several stripes
together, so scribble data should be able to cover several stripes, so this
patch also allocates scribble data for stripes across a chunk.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 08:00:41 +10:00
Heinz Mauelshagen
753f2856cd md raid0: access mddev->queue (request queue member) conditionally because it is not set when accessed from dm-raid
The patch makes 3 references to mddev->queue in the raid0 personality
conditional in order to allow for it to be accessed from dm-raid.
Mandatory, because md instances underneath dm-raid don't manage
a request queue of their own which'd lead to oopses without the patch.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Tested-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 08:00:41 +10:00
NeilBrown
ac8fa4196d md: allow resync to go faster when there is competing IO.
When md notices non-sync IO happening while it is trying
to resync (or reshape or recover) it slows down to the
set minimum.

The default minimum might have made sense many years ago
but the drives have become faster.  Changing the default
to match the times isn't really a long term solution.

This patch changes the code so that instead of waiting until the speed
has dropped to the target, it just waits until pending requests
have completed.
This means that the delay inserted is a function of the speed
of the devices.

Testing shows that:
 - for some loads, the resync speed is unchanged.  For those loads
   increasing the minimum doesn't change the speed either.
   So this is a good result.  To increase resync speed under such
   loads we would probably need to increase the resync window
   size.

 - for other loads, resync speed does increase to a reasonable
   fraction (e.g. 20%) of maximum possible, and throughput of
   the load only drops a little bit (e.g. 10%)

 - for other loads, throughput of the non-sync load drops quite a bit
   more.  These seem to be latency-sensitive loads.

So it isn't a perfect solution, but it is mostly an improvement.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 08:00:40 +10:00
NeilBrown
09314799e4 md: remove 'go_faster' option from ->sync_request()
This option is not well justified and testing suggests that
it hardly ever makes any difference.

The comment suggests there might be a need to wait for non-resync
activity indicated by ->nr_waiting, however raise_barrier()
already waits for all of that.

So just remove it to simplify reasoning about speed limiting.

This allows us to remove a 'FIXME' comment from raid5.c as that
never used the flag.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 08:00:40 +10:00
NeilBrown
50c37b136a md: don't require sync_min to be a multiple of chunk_size.
There is really no need for sync_min to be a multiple of
chunk_size, and values read from here often aren't.
That means you cannot read a value and expect to be able
to write it back later.

So remove the chunk_size check, and round down to a multiple
of 4K, to be sure everything works with 4K-sector devices.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 08:00:40 +10:00
NeilBrown
d51e4fe6d6 Merge branch 'cluster' into for-next 2015-04-22 08:00:20 +10:00
Goldwyn Rodrigues
97f6cd39da md-cluster: re-add capabilities
When "re-add" is writted to /sys/block/mdXX/md/dev-YYY/state,
the clustered md:

1. Sends RE_ADD message with the desc_nr. Nodes receiving the message
   clear the Faulty bit in their respective rdev->flags.
2. The node initiating re-add, gathers the bitmaps of all nodes
   and copies them into the local bitmap. It does not clear the bitmap
   from which it is copying.
3. Initiating node schedules a md recovery to sync the devices.

Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 07:59:39 +10:00
Goldwyn Rodrigues
a6da4ef85c md: re-add a failed disk
This adds the capability of re-adding a failed disk by
writing "re-add" to /sys/block/mdXX/md/dev-YYY/state.

This facilitates adding disks which have encountered a temporary
error such as a network disconnection/hiccup in an iSCSI device,
or a SAN cable disconnection which has been restored. In such
a situation, you do not need to remove and re-add the device.
Writing re-add to the failed device's state would add it again
to the array and perform the recovery of only the blocks which
were written after the device failed.

This works for generic md, and is not related to clustering. However,
this patch is to ease re-add operations listed above in clustering
environments.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 07:59:39 +10:00
Goldwyn Rodrigues
88bcfef7be md-cluster: remove capabilities
This adds "remove" capabilities for the clustered environment.
When a user initiates removal of a device from the array, a
REMOVE message with disk number in the array is sent to all
the nodes which kick the respective device in their own array.

This facilitates the removal of failed devices.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 07:59:39 +10:00
Goldwyn Rodrigues
57d051dcca md: Export and rename find_rdev_nr_rcu
This is required by the clustering module (patches to follow) to
find the device to remove or re-add.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 07:59:39 +10:00
Goldwyn Rodrigues
fb56dfef4e md: Export and rename kick_rdev_from_array
This export is required for clustering module in order to
co-ordinate remove/readd a rdev from all nodes.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 07:59:39 +10:00
Guoqing Jiang
8c58f02e24 md-cluster: correct the num for comparison
Since the node num of md-cluster is from zero, and
cinfo->slot_number represents the slot num of dlm,
no need to check for equality.

Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 07:58:31 +10:00
Linus Torvalds
afad97eee4 - Most extensive changes this cycle are the DM core improvements to add
full blk-mq support to request-based DM.
   - disabled by default but user can opt-in with CONFIG_DM_MQ_DEFAULT
   - depends on some blk-mq changes from Jens' for-4.1/core branch so
     that explains why this pull is built on linux-block.git
 
 - Update DM to use name_to_dev_t() rather than open-coding a less
   capable device parser.
   - includes a couple small improvements to name_to_dev_t() that offer
     stricter constraints that DM's code provided.
 
 - Improvements to the dm-cache "mq" cache replacement policy.
 
 - A DM crypt crypt_ctr() error path fix and an async crypto deadlock fix.
 
 - A small efficiency improvement for DM crypt decryption by leveraging
   immutable biovecs.
 
 - Add error handling modes for corrupted blocks to DM verity.
 
 - A new "log-writes" DM target from Josef Bacik that is meant for
   file system developers to test file system integrity at particular
   points in the life of a file system.
 
 - A few DM log userspace cleanups and fixes.
 
 - A few Documentation fixes (for thin, cache, crypt and switch).
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 
 iQEcBAABAgAGBQJVMGvhAAoJEMUj8QotnQNaOKgH/iuWyEZ+ndWbeEBZs9ZJPEgU
 sRiKjSaPujkdB+78o+2DfAYjwCchqH1Oy781PqG85asTENVkcjD7LBPaIom/A2ml
 Z9ZeCzAKbrtB3lZR8QAg4u7+90kkuZv1SeOPMWBZCEV4GYLEpV1J4/f+RgdEs1kT
 upQcH1fFoQdyHGikwAKXf85Gmi4OrjVb19yoxu2xZnfwT2sCPq0okU4yBxb1B9mL
 X/FcHUeLS9LJGewEqTD3AvWrk+J5pqj+1EeKY2kRxisp1065TaljYwetgR76Vnfb
 o0J5eovJVL3AKRTYxvr5JABWD09xq9nG1hVBiuQMN5VmmvxjDKdbBPaKI4dZTt0=
 =uVjp
 -----END PGP SIGNATURE-----

Merge tag 'dm-4.1-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - the most extensive changes this cycle are the DM core improvements to
   add full blk-mq support to request-based DM.

    - disabled by default but user can opt-in with CONFIG_DM_MQ_DEFAULT
    - depends on some blk-mq changes from Jens' for-4.1/core branch so
      that explains why this pull is built on linux-block.git

 - update DM to use name_to_dev_t() rather than open-coding a less
   capable device parser.

    - includes a couple small improvements to name_to_dev_t() that offer
      stricter constraints that DM's code provided.

 - improvements to the dm-cache "mq" cache replacement policy.

 - a DM crypt crypt_ctr() error path fix and an async crypto deadlock
   fix

 - a small efficiency improvement for DM crypt decryption by leveraging
   immutable biovecs

 - add error handling modes for corrupted blocks to DM verity

 - a new "log-writes" DM target from Josef Bacik that is meant for file
   system developers to test file system integrity at particular points
   in the life of a file system

 - a few DM log userspace cleanups and fixes

 - a few Documentation fixes (for thin, cache, crypt and switch)

* tag 'dm-4.1-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (34 commits)
  dm crypt: fix missing error code return from crypt_ctr error path
  dm crypt: fix deadlock when async crypto algorithm returns -EBUSY
  dm crypt: leverage immutable biovecs when decrypting on read
  dm crypt: update URLs to new cryptsetup project page
  dm: add log writes target
  dm table: use bool function return values of true/false not 1/0
  dm verity: add error handling modes for corrupted blocks
  dm thin: remove stale 'trim' message documentation
  dm delay: use msecs_to_jiffies for time conversion
  dm log userspace base: fix compile warning
  dm log userspace transfer: match wait_for_completion_timeout return type
  dm table: fall back to getting device using name_to_dev_t()
  init: stricter checking of major:minor root= values
  init: export name_to_dev_t and mark name argument as const
  dm: add 'use_blk_mq' module param and expose in per-device ro sysfs attr
  dm: optimize dm_mq_queue_rq to _not_ use kthread if using pure blk-mq
  dm: add full blk-mq support to request-based DM
  dm: impose configurable deadline for dm_request_fn's merge heuristic
  dm sysfs: introduce ability to add writable attributes
  dm: don't start current request if it would've merged with the previous
  ...
2015-04-18 08:14:18 -04:00
Wei Yongjun
44c144f9c8 dm crypt: fix missing error code return from crypt_ctr error path
Fix to return a negative error code from crypt_ctr()'s optional
parameter processing error path.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-16 22:00:50 -04:00
Ben Collins
0618764cb2 dm crypt: fix deadlock when async crypto algorithm returns -EBUSY
I suspect this doesn't show up for most anyone because software
algorithms typically don't have a sense of being too busy.  However,
when working with the Freescale CAAM driver it will return -EBUSY on
occasion under heavy -- which resulted in dm-crypt deadlock.

After checking the logic in some other drivers, the scheme for
crypt_convert() and it's callback, kcryptd_async_done(), were not
correctly laid out to properly handle -EBUSY or -EINPROGRESS.

Fix this by using the completion for both -EBUSY and -EINPROGRESS.  Now
crypt_convert()'s use of completion is comparable to
af_alg_wait_for_completion().  Similarly, kcryptd_async_done() follows
the pattern used in af_alg_complete().

Before this fix dm-crypt would lockup within 1-2 minutes running with
the CAAM driver.  Fix was regression tested against software algorithms
on PPC32 and x86_64, and things seem perfectly happy there as well.

Signed-off-by: Ben Collins <ben.c@servergy.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-04-15 12:10:26 -04:00
Mike Snitzer
5977907937 dm crypt: leverage immutable biovecs when decrypting on read
Commit 003b5c571 ("block: Convert drivers to immutable biovecs")
stopped short of changing dm-crypt to leverage the fact that the biovec
array of a bio will no longer be modified.

Switch to using bio_clone_fast() when cloning bios for decryption after
read.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:25 -04:00
Milan Broz
e44f23b32d dm crypt: update URLs to new cryptsetup project page
Cryptsetup home page moved to GitLab.
Also remove link to abandonded Truecrypt page.

Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:24 -04:00
Josef Bacik
0e9cebe724 dm: add log writes target
Introduce a new target that is meant for file system developers to test file
system integrity at particular points in the life of a file system.  We capture
all write requests and associated data and log them to a separate device
for later replay.  There is a userspace utility to do this replay.  The
idea behind this is to give file system developers a tool to verify that
the file system is always consistent.

Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Zach Brown <zab@zabbo.net>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:24 -04:00
Joe Perches
7f61f5a022 dm table: use bool function return values of true/false not 1/0
Use the normal return values for bool functions.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:23 -04:00
Sami Tolvanen
65ff5b7ddf dm verity: add error handling modes for corrupted blocks
Add device specific modes to dm-verity to specify how corrupted
blocks should be handled.  The following modes are defined:

  - DM_VERITY_MODE_EIO is the default behavior, where reading a
    corrupted block results in -EIO.

  - DM_VERITY_MODE_LOGGING only logs corrupted blocks, but does
    not block the read.

  - DM_VERITY_MODE_RESTART calls kernel_restart when a corrupted
    block is discovered.

In addition, each mode sends a uevent to notify userspace of
corruption and to allow further recovery actions.

The driver defaults to previous behavior (DM_VERITY_MODE_EIO)
and other modes can be enabled with an additional parameter to
the verity table.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:22 -04:00
Nicholas Mc Guire
aca607ba24 dm delay: use msecs_to_jiffies for time conversion
Converting milliseconds to jiffies by "val * HZ / 1000" is technically
OK but msecs_to_jiffies(val) is the cleaner solution and handles all
corner cases correctly.

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:21 -04:00
Nicholas Mc Guire
18cc980ac8 dm log userspace base: fix compile warning
This fixes up a compile warning [-Wunused-but-set-variable] - given the
comment in userspace_set_region_sync() the non-reporting of errors is
intentional so the return value can be dropped to make gcc happy.

Also, fix typo in comment.

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:20 -04:00
Nicholas Mc Guire
c32a512fdf dm log userspace transfer: match wait_for_completion_timeout return type
Return type of wait_for_completion_timeout() is unsigned long not int.
An appropriately named unsigned long is added and the assignment fixed.

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:20 -04:00