Commit Graph

3998 Commits

Author SHA1 Message Date
Joe Thornber
651f5fa2a3 dm cache: defer whole cells
Currently individual bios are deferred to the worker thread if they
cannot be processed immediately (eg, a block is in the process of
being moved to the fast device).

This patch passes whole cells across to the worker.  This saves
reaquiring the cell, and also collects bios destined for the same block
together, which allows them to be mapped with a single look up to the
policy.  This reduces the overhead of using dm-cache.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:19:06 -04:00
Joe Thornber
3cdf93f9d8 dm bio prison: add dm_cell_promote_or_release()
Rather than always releasing the prisoners in a cell, the client may
want to promote one of them to be the new holder.  There is a race here
though between releasing an empty cell, and other threads adding new
inmates.  So this function makes the decision with its lock held.

This function can have two outcomes:
i)  An inmate is promoted to be the holder of the cell (return value of 0).
ii) The cell has no inmate for promotion and is released (return value of 1).

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:19:06 -04:00
Joe Thornber
451b9e0071 dm cache: pull out some bitset utility functions for reuse
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:19:05 -04:00
Joe Thornber
20f6814b94 dm cache: pass a new 'critical' flag to the policies when requesting writeback work
We only allow non critical writeback if the origin is idle.  It is up
to the policy to decide what writeback work is critical.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:19:04 -04:00
Joe Thornber
066dbaa386 dm cache: track IO to the origin device using io_tracker
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:19:04 -04:00
Joe Thornber
77289d3207 dm cache: add io_tracker
A little class that keeps track of the volume of io that is in flight,
and the length of time that a device has been idle for.

FIXME: rather than jiffes, may be best to use ktime_t (to support faster
devices).

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:19:03 -04:00
Joe Thornber
fb4100ae7f dm cache: fix race when issuing a POLICY_REPLACE operation
There is a race between a policy deciding to replace a cache entry,
the core target writing back any dirty data from this block, and other
IO threads doing IO to the same block.

This sort of problem is avoided most of the time by the core target
grabbing a bio prison cell before making the request to the policy.
But for a demotion the core target doesn't know which block will be
demoted, so can't do this in advance.

Fix this demotion race by introducing a callback to the policy interface
that allows the policy to grab the cell on behalf of the core target.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-05-29 14:19:03 -04:00
Milan Broz
54cea3f668 dm crypt: add comments to better describe crypto processing logic
A crypto driver can process requests synchronously or asynchronously
and can use an internal driver queue to backlog requests.
Add some comments to clarify internal logic and completion return codes.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:19:02 -04:00
Lidong Zhong
ed63287dd6 dm raid1: keep issuing IO after leg failure
Currently if there is a leg failure, the bio will be put into the hold
list until userspace does a remove/replace on the leg.  Doing so in a
cluster config (clvmd) is problematic because there may be a temporary
path failure that results in cluster raid1 remove/replace.  Such
recovery takes a long time due to a full resync.

Update dm-raid1 to optionally ignore these failures so bios continue
being issued without interrupton.  To enable this feature userspace
must pass "keep_log" when creating the dm-raid1 device.

Signed-off-by: Lidong Zhong <lzhong@suse.com>
Tested-by: Liuhua Wang <lwang@suse.com>
Acked-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:19:02 -04:00
Geert Uytterhoeven
f4ad317aed dm log writes: use ULL suffix for 64-bit constants
On 32-bit:
drivers/md/dm-log-writes.c: In function ‘log_super’:
drivers/md/dm-log-writes.c:323: warning: integer constant is too large for ‘long’ type

Add a ULL suffix to WRITE_LOG_MAGIC to fix this.
Also add a ULL suffix to WRITE_LOG_VERSION as it's stored in a __le64
field.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:19:01 -04:00
Luis Henriques
e223e1de4f dm stripe: drop useless exit point from dm_stripe_init()
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:19:01 -04:00
Heinz Mauelshagen
0cf4503174 dm raid: add support for the MD RAID0 personality
Add dm-raid access to the MD RAID0 personality to enable single zone
striping.

The following changes enable that access:
- add type definition to raid_types array
- make bitmap creation conditonal in super_validate(), because
  bitmaps are not allowed in raid0
- set rdev->sectors to the data image size in super_validate()
  to allow the raid0 personality to calculate the MD array
  size properly
- use mdddev(un)lock() functions instead of direct mutex_(un)lock()
  (wrapped in here because it's a trivial change)
- enhance raid_status() to always report full sync for raid0
  so that userspace checks for 100% sync will succeed and allow
  for resize (and takeover/reshape once added in future paches)
- enhance raid_resume() to not load bitmap in case of raid0
- add merge function to avoid data corruption (seen with readahead)
  that resulted from bio payloads that grew too large.  This problem
  did not occur with the other raid levels because it either did not
  apply without striping (raid1) or was avoided via stripe caching.
- raise version to 1.7.0 because of the raid0 API change

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:19:00 -04:00
Heinz Mauelshagen
c76d53f43e dm raid: a few cleanups
- ensure maximum device limit in superblock
- rename DMPF_* (print flags) to CTR_FLAG_* (constructor flags)
  and their respective struct raid_set member
- use strcasecmp() in raid10_format_to_md_layout() as in the constructor

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:19:00 -04:00
Heinz Mauelshagen
0f4106b32f dm raid: fixup documentation for discard support
Remove comment above parse_raid_params() that claims
"devices_handle_discard_safely" is a table line argument when it is
actually is a module parameter.

Also, backfill dm-raid target version 1.6.0 documentation.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:18:59 -04:00
Mike Snitzer
49f154c732 dm thin metadata: remove in-core 'read_only' flag
Leverage the block manager's read_only flag instead of duplicating it;
access with new dm_bm_is_read_only() method.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:18:59 -04:00
Mike Snitzer
f8ae75253e dm thin: cleanup schedule_zero() to read more logically
The overwrite has only ever about optimizing away the need to zero a
block if the entire block was being overwritten.  As such it is only
relevant when zeroing is enabled.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
2015-05-29 14:18:58 -04:00
Mike Snitzer
8b908f8e94 dm thin: cleanup overwrite's endio restore to be centralized
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:18:58 -04:00
Mike Snitzer
0f20972f7b dm: factor out a common cleanup_mapped_device()
Introduce a single common method for cleaning up a DM device's
mapped_device.  No functional change, just eliminates duplication of
delicate mapped_device cleanup code.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:18:58 -04:00
Mike Snitzer
2d76fff18f dm: cleanup methods that requeue requests
More often than not a request that is requeued _is_ mapped (meaning the
clone request is allocated and clone->q is initialized).  Rename
dm_requeue_unmapped_original_request() to avoid potential confusion due
to function name containing "unmapped".

Also, remove dm_requeue_unmapped_request() since callers can easily call
the dm_requeue_original_request() directly.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:18:57 -04:00
Mike Snitzer
cbc4e3c135 dm: do not allocate any mempools for blk-mq request-based DM
Do not allocate the io_pool mempool for blk-mq request-based DM
(DM_TYPE_MQ_REQUEST_BASED) in dm_alloc_rq_mempools().

Also refine __bind_mempools() to have more precise awareness of which
mempools each type of DM device uses -- avoids mempool churn when
reloading DM tables (particularly for DM_TYPE_REQUEST_BASED).

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:18:57 -04:00
Mike Snitzer
183f7802e7 Merge remote-tracking branch 'jens/for-4.2/core' into dm-4.2 2015-05-29 14:17:16 -04:00
Joe Thornber
1c220c69ce dm: fix casting bug in dm_merge_bvec()
dm_merge_bvec() was originally added in f6fccb ("dm: introduce
merge_bvec_fn").  In that commit a value in sectors is converted to
bytes using << 9, and then assigned to an int.  This code made
assumptions about the value of BIO_MAX_SECTORS.

A later commit 148e51 ("dm: improve documentation and code clarity in
dm_merge_bvec") was meant to have no functional change but it removed
the use of BIO_MAX_SECTORS in favor of using queue_max_sectors().  At
this point the cast from sector_t to int resulted in a zero value.  The
fallout being dm_merge_bvec() would only allow a single page to be added
to a bio.

This interim fix is minimal for the benefit of stable@ because the more
comprehensive cleanup of passing a sector_t to all DM targets' merge
function will impact quite a few DM targets.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 3.19+
2015-05-29 13:41:16 -04:00
Junichi Nomura
15b94a6904 dm: fix reload failure of 0 path multipath mapping on blk-mq devices
dm-multipath accepts 0 path mapping.

  # echo '0 2097152 multipath 0 0 0 0' | dmsetup create newdev

Such a mapping can be used to release underlying devices while still
holding requests in its queue until working paths come back.

However, once the multipath device is created over blk-mq devices,
it rejects reloading of 0 path mapping:

  # echo '0 2097152 multipath 0 0 1 1 queue-length 0 1 1 /dev/sda 1' \
      | dmsetup create mpath1
  # echo '0 2097152 multipath 0 0 0 0' | dmsetup load mpath1
  device-mapper: reload ioctl on mpath1 failed: Invalid argument
  Command failed

With following kernel message:
  device-mapper: ioctl: can't change device type after initial table load.

DM tries to inherit the current table type using dm_table_set_type()
but it doesn't work as expected because of unnecessary check about
whether the target type is hybrid or not.

Hybrid type is for targets that work as either request-based or bio-based
and not required for blk-mq or non blk-mq checking.

Fixes: 65803c2059 ("dm table: train hybrid target type detection to select blk-mq if appropriate")
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 13:41:16 -04:00
Linus Torvalds
c492e2d464 Assorted fixes for new RAID5 stripe-batching functionality.
Unfortunately this functionality was merged a little prematurely.
 The necessary testing and code review is now complete (or as
 complete as it can be) and to code passes a variety of tests
 and looks quite sensible.
 
 Also a fix for some recent locking changes - a race was introduced
 which causes a reshape request to sometimes fail.  No data safety issues.
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Merge tag 'md/4.1-rc5-fixes' of git://neil.brown.name/md

Pull m,ore md bugfixes gfrom Neil Brown:
 "Assorted fixes for new RAID5 stripe-batching functionality.

  Unfortunately this functionality was merged a little prematurely.  The
  necessary testing and code review is now complete (or as complete as
  it can be) and to code passes a variety of tests and looks quite
  sensible.

  Also a fix for some recent locking changes - a race was introduced
  which causes a reshape request to sometimes fail.  No data safety
  issues"

* tag 'md/4.1-rc5-fixes' of git://neil.brown.name/md:
  md: fix race when unfreezing sync_action
  md/raid5: break stripe-batches when the array has failed.
  md/raid5: call break_stripe_batch_list from handle_stripe_clean_event
  md/raid5: be more selective about distributing flags across batch.
  md/raid5: add handle_flags arg to break_stripe_batch_list.
  md/raid5: duplicate some more handle_stripe_clean_event code in break_stripe_batch_list
  md/raid5: remove condition test from check_break_stripe_batch_list.
  md/raid5: Ensure a batch member is not handled prematurely.
  md/raid5: close race between STRIPE_BIT_DELAY and batching.
  md/raid5: ensure whole batch is delayed for all required bitmap updates.
2015-05-29 10:35:21 -07:00
Mike Snitzer
e5d8de32cc dm: fix false warning in free_rq_clone() for unmapped requests
When stacking request-based dm device on non blk-mq device and
device-mapper target could not map the request (error target is used,
multipath target with all paths down, etc), the WARN_ON_ONCE() in
free_rq_clone() will trigger when it shouldn't.

The warning was added by commit aa6df8d ("dm: fix free_rq_clone() NULL
pointer when requeueing unmapped request").  But free_rq_clone() with
clone->q == NULL is valid usage for the case where
dm_kill_unmapped_request() initiates request cleanup.

Fix this false warning by just removing the WARN_ON -- it only generated
false positives and was never useful in catching the intended case
(completing clone request not being mapped e.g. clone->q being NULL).

Fixes: aa6df8d ("dm: fix free_rq_clone() NULL pointer when requeueing unmapped request")
Reported-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reported-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 11:07:36 -04:00
NeilBrown
56ccc1125b md: fix race when unfreezing sync_action
A recent change removed the need for locking around writing
to "sync_action" (and various other places), but introduced a
subtle race.
When e.g. setting 'reshape' on a 'frozen' array, the 'frozen'
flag is cleared before 'reshape' is set, so the md thread can
get in and start trying recovery - which isn't wanted.

So instead of clearing MD_RECOVERY_FROZEN for any command
except 'frozen', only clear it when each specific command
is parsed.  This allows the handling of 'reshape' to clear
the bit while a lock is held.

Also remove some places where we set MD_RECOVERY_NEEDED,
as it is always set on non-error exit of the function.


Signed-off-by: NeilBrown <neilb@suse.de>
Fixes: 6791875e2e ("md: make reconfig_mutex optional for writes to md sysfs files.")
2015-05-28 18:04:45 +10:00
NeilBrown
626f2092c8 md/raid5: break stripe-batches when the array has failed.
Once the array has too much failure, we need to break
stripe-batches up so they can all be dealt with.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-05-28 11:48:59 +10:00
NeilBrown
787b76fa37 md/raid5: call break_stripe_batch_list from handle_stripe_clean_event
Now that the code in break_stripe_batch_list() is nearly identical
to the end of handle_stripe_clean_event, replace the later
with a function call.

The only remaining difference of any interest is the masking that is
applieds to dev[i].flags copied from head_sh.
R5_WriteError certainly isn't wanted as it is set per-stripe, not
per-patch.  R5_Overlap isn't wanted as it is explicitly handled.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-05-28 11:47:02 +10:00
NeilBrown
1b956f7a8f md/raid5: be more selective about distributing flags across batch.
When a batch of stripes is broken up, we keep some of the flags
that were per-stripe, and copy other flags from the head to all
others.

This only happens while a stripe is being handled, so many of the
flags are irrelevant.

The "SYNC_FLAGS" (which I've renamed to make it clear there are
several) and STRIPE_DEGRADED are set per-stripe and so need to be
preserved.  STRIPE_INSYNC is the only flag that is set on the head
that needs to be propagated to all others.

For safety, add a WARN_ON if others are set, except:
 STRIPE_HANDLE - this is safe and per-stripe and we are going to set
      in several cases anyway
 STRIPE_INSYNC
 STRIPE_IO_STARTED - this is just a hint and doesn't hurt.
 STRIPE_ON_PLUG_LIST
 STRIPE_ON_RELEASE_LIST - It is a point pointless for a batched
           stripe to be on one of these lists, but it can happen
           as can be safely ignored.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-05-28 11:40:01 +10:00
NeilBrown
3960ce7961 md/raid5: add handle_flags arg to break_stripe_batch_list.
When we break a stripe_batch_list we sometimes want to set
STRIPE_HANDLE on the individual stripes, and sometimes not.

So pass a 'handle_flags' arg.  If it is zero, always set STRIPE_HANDLE
(on non-head stripes).  If not zero, only set it if any of the given
flags are present.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-05-28 11:39:30 +10:00
NeilBrown
fb642b92c2 md/raid5: duplicate some more handle_stripe_clean_event code in break_stripe_batch_list
break_stripe_batch list didn't clear head_sh->batch_head.
This was probably a bug.

Also clear all R5_Overlap flags and if any were cleared, wake up
'wait_for_overlap'.
This isn't always necessary but the worst effect is a little
extra checking for code that is waiting on wait_for_overlap.

Also, don't use wake_up_nr() because that does the wrong thing
if 'nr' is zero, and it number of flags cleared doesn't
strongly correlate with the number of threads to wake.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-05-28 11:36:25 +10:00
NeilBrown
4e3d62ff49 md/raid5: remove condition test from check_break_stripe_batch_list.
handle_stripe_clean_event() contains a chunk of code very
similar to check_break_stripe_batch_list().
If we make the latter more like the former, we can end up
with just one copy of this code.

This  first step removed the condition (and the 'check_') part
of the name.  This has the added advantage of making it clear
what check is being performed at the point where the function is
called.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-05-28 11:36:06 +10:00
NeilBrown
b15a9dbdbf md/raid5: Ensure a batch member is not handled prematurely.
If a stripe is a member of a batch, but not the head, it must
not be handled separately from the rest of the batch.

'clear_batch_ready()' handles this requirement to some
extent but not completely.  If a member is passed to handle_stripe()
a second time it returns '0' indicating the stripe can be handled,
which is wrong.
So add an extra test.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-05-28 11:35:47 +10:00
NeilBrown
d0852df543 md/raid5: close race between STRIPE_BIT_DELAY and batching.
When we add a write to a stripe we need to make sure the bitmap
bit is set.  While doing that the stripe is not locked so it could
be added to a batch after which further changes to STRIPE_BIT_DELAY
and ->bm_seq are ineffective.

So we need to hold off adding to a stripe until bitmap_startwrite has
completed at least once, and we need to avoid further changes to
STRIPE_BIT_DELAY once the stripe has been added to a batch.

If a bitmap_startwrite() completes after the stripe was added to a
batch, it will not have set the bit, only incremented a counter, so no
extra delay of the stripe is needed.

Reported-by: Shaohua Li <shli@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-05-28 11:34:40 +10:00
NeilBrown
2b6b245742 md/raid5: ensure whole batch is delayed for all required bitmap updates.
When we add a stripe to a batch, we need to be sure that
head stripe will wait for the bitmap update required for the new
stripe.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-05-28 11:29:14 +10:00
Mike Snitzer
45714fbed4 dm: requeue from blk-mq dm_mq_queue_rq() using BLK_MQ_RQ_QUEUE_BUSY
Use BLK_MQ_RQ_QUEUE_BUSY to requeue a blk-mq request directly from the
DM blk-mq device's .queue_rq.  This cleans up the previous convoluted
handling of request requeueing that would return BLK_MQ_RQ_QUEUE_OK
(even though it wasn't) and then run blk_mq_requeue_request() followed
by blk_mq_kick_requeue_list().

Also, document that DM blk-mq ontop of old request_fn devices cannot
fail in clone_rq() since the clone request is preallocated as part of
the pdu.

Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-27 17:37:23 -04:00
Mike Snitzer
4c6dd53dd3 dm mpath: fix leak of dm_mpath_io structure in blk-mq .queue_rq error path
Otherwise kmemleak reported:

unreferenced object 0xffff88009b14e2b0 (size 16):
  comm "fio", pid 4274, jiffies 4294978034 (age 1253.210s)
  hex dump (first 16 bytes):
    40 12 f3 99 01 88 ff ff 00 10 00 00 00 00 00 00  @...............
  backtrace:
    [<ffffffff81600029>] kmemleak_alloc+0x49/0xb0
    [<ffffffff811679a8>] kmem_cache_alloc+0xf8/0x160
    [<ffffffff8111c950>] mempool_alloc_slab+0x10/0x20
    [<ffffffff8111cb37>] mempool_alloc+0x57/0x150
    [<ffffffffa04d2b61>] __multipath_map.isra.17+0xe1/0x220 [dm_multipath]
    [<ffffffffa04d2cb5>] multipath_clone_and_map+0x15/0x20 [dm_multipath]
    [<ffffffffa02889b5>] map_request.isra.39+0xd5/0x220 [dm_mod]
    [<ffffffffa028b0e4>] dm_mq_queue_rq+0x134/0x240 [dm_mod]
    [<ffffffff812cccb5>] __blk_mq_run_hw_queue+0x1d5/0x380
    [<ffffffff812ccaa5>] blk_mq_run_hw_queue+0xc5/0x100
    [<ffffffff812ce350>] blk_sq_make_request+0x240/0x300
    [<ffffffff812c0f30>] generic_make_request+0xc0/0x110
    [<ffffffff812c0ff2>] submit_bio+0x72/0x150
    [<ffffffff811c07cb>] do_blockdev_direct_IO+0x1f3b/0x2da0
    [<ffffffff811c166e>] __blockdev_direct_IO+0x3e/0x40
    [<ffffffff8120aa1a>] ext4_direct_IO+0x1aa/0x390

Fixes: e5863d9ad ("dm: allocate requests in target when stacking on blk-mq devices")
Reported-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 4.0+
2015-05-27 17:37:22 -04:00
Junichi Nomura
3a1407559a dm: fix NULL pointer when clone_and_map_rq returns !DM_MAPIO_REMAPPED
When stacking request-based DM on blk_mq device, request cloning and
remapping are done in a single call to target's clone_and_map_rq().
The clone is allocated and valid only if clone_and_map_rq() returns
DM_MAPIO_REMAPPED.

The "IS_ERR(clone)" check in map_request() does not cover all the
!DM_MAPIO_REMAPPED cases that are possible (E.g. if underlying devices
are not ready or unavailable, clone_and_map_rq() may return
DM_MAPIO_REQUEUE without ever having established an ERR_PTR).  Fix this
by explicitly checking for a return that is not DM_MAPIO_REMAPPED in
map_request().

Without this fix, DM core may call setup_clone() for a NULL clone
and oops like this:

   BUG: unable to handle kernel NULL pointer dereference at 0000000000000068
   IP: [<ffffffff81227525>] blk_rq_prep_clone+0x7d/0x137
   ...
   CPU: 2 PID: 5793 Comm: kdmwork-253:3 Not tainted 4.0.0-nm #1
   ...
   Call Trace:
    [<ffffffffa01d1c09>] map_tio_request+0xa9/0x258 [dm_mod]
    [<ffffffff81071de9>] kthread_worker_fn+0xfd/0x150
    [<ffffffff81071cec>] ? kthread_parkme+0x24/0x24
    [<ffffffff81071cec>] ? kthread_parkme+0x24/0x24
    [<ffffffff81071fdd>] kthread+0xe6/0xee
    [<ffffffff81093a59>] ? put_lock_stats+0xe/0x20
    [<ffffffff81071ef7>] ? __init_kthread_worker+0x5b/0x5b
    [<ffffffff814c2d98>] ret_from_fork+0x58/0x90
    [<ffffffff81071ef7>] ? __init_kthread_worker+0x5b/0x5b

Fixes: e5863d9ad ("dm: allocate requests in target when stacking on blk-mq devices")
Reported-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 4.0+
2015-05-27 09:48:51 -04:00
Junichi Nomura
4ae9944d13 dm: run queue on re-queue
Without kicking queue, requeued request may stay forever in
the queue if there are no other I/O activities to the device.

The original error had been in v2.6.39 with commit 7eaceaccab
("block: remove per-queue plugging"), which replaced conditional
plugging by periodic runqueue.

Commit 9d1deb83d4 in v4.1-rc1 removed the periodic runqueue
and the problem started to manifest.

Fixes: 9d1deb83d4 ("dm: don't schedule delayed run of the queue if nothing to do")
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-26 09:57:36 -04:00
Linus Torvalds
a30ec4b347 md fixes for 4.1-rc4
- one serious RAID0 data corruption - caused by recent bugfix that wasn't
   reviewed properly.
 - one raid5 fix in new code (a couple more of those to come).
 - one little fix to stop static analysis complaining about silly rcu
   annotation.
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Merge tag 'md/4.1-rc4-fixes' of git://neil.brown.name/md

Pull md bugfixes from Neil Brown:
 "I have a few more raid5 bugfixes pending, but I want them to get a bit
  more review first.  In the meantime:

   - one serious RAID0 data corruption - caused by recent bugfix that
     wasn't reviewed properly.

   - one raid5 fix in new code (a couple more of those to come).

   - one little fix to stop static analysis complaining about silly rcu
     annotation"

* tag 'md/4.1-rc4-fixes' of git://neil.brown.name/md:
  md/bitmap: remove rcu annotation from pointer arithmetic.
  md/raid0: fix restore to sector variable in raid0_make_request
  raid5: fix broken async operation chain
2015-05-22 15:10:07 -07:00
Christoph Hellwig
5f1b670d0b block, dm: don't copy bios for request clones
Currently dm-multipath has to clone the bios for every request sent
to the lower devices, which wastes cpu cycles and ties down memory.

This patch instead adds a new REQ_CLONE flag that instructs req_bio_endio
to not complete bios attached to a request, which we set on clone
requests similar to bios in a flush sequence.  With this change I/O
errors on a path failure only get propagated to dm-multipath, which
can then either resubmit the I/O or complete the bios on the original
request.

I've done some basic testing of this on a Linux target with ALUA support,
and it survives path failures during I/O nicely.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-22 08:58:57 -06:00
Mike Snitzer
326e1dbb57 block: remove management of bi_remaining when restoring original bi_end_io
Commit c4cf5261 ("bio: skip atomic inc/dec of ->bi_remaining for
non-chains") regressed all existing callers that followed this pattern:
 1) saving a bio's original bi_end_io
 2) wiring up an intermediate bi_end_io
 3) restoring the original bi_end_io from intermediate bi_end_io
 4) calling bio_endio() to execute the restored original bi_end_io

The regression was due to BIO_CHAIN only ever getting set if
bio_inc_remaining() is called.  For the above pattern it isn't set until
step 3 above (step 2 would've needed to establish BIO_CHAIN).  As such
the first bio_endio(), in step 2 above, never decremented __bi_remaining
before calling the intermediate bi_end_io -- leaving __bi_remaining with
the value 1 instead of 0.  When bio_inc_remaining() occurred during step
3 it brought it to a value of 2.  When the second bio_endio() was
called, in step 4 above, it should've called the original bi_end_io but
it didn't because there was an extra reference that wasn't dropped (due
to atomic operations being optimized away since BIO_CHAIN wasn't set
upfront).

Fix this issue by removing the __bi_remaining management complexity for
all callers that use the above pattern -- bio_chain() is the only
interface that _needs_ to be concerned with __bi_remaining.  For the
above pattern callers just expect the bi_end_io they set to get called!
Remove bio_endio_nodec() and also remove all bio_inc_remaining() calls
that aren't associated with the bio_chain() interface.

Also, the bio_inc_remaining() interface has been moved local to bio.c.

Fixes: c4cf5261 ("bio: skip atomic inc/dec of ->bi_remaining for non-chains")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-22 08:58:55 -06:00
NeilBrown
8532e34390 md/bitmap: remove rcu annotation from pointer arithmetic.
Evaluating  "&mddev->disks" is simple pointer arithmetic, so
it does not need 'rcu' annotations - no dereferencing is happening.

Also enhance the comment to explain that 'rdev' in that case
is not actually a pointer to an rdev.

Reported-by: Patrick Marlier <patrick.marlier@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-05-21 09:14:41 +10:00
Eric Work
a81157768a md/raid0: fix restore to sector variable in raid0_make_request
The variable "sector" in "raid0_make_request()" was improperly updated
by a call to "sector_div()" which modifies its first argument in place.
Commit 47d68979cc restored this variable
after the call for later re-use.  Unfortunetly the restore was done after
the referenced variable "bio" was advanced.  This lead to the original
value and the restored value being different.  Here we move this line to
the proper place.

One observed side effect of this bug was discarding a file though
unlinking would cause an unrelated file's contents to be discarded.

Signed-off-by: NeilBrown <neilb@suse.de>
Fixes: 47d68979cc ("md/raid0: fix bug with chunksize not a power of 2.")
Cc: stable@vger.kernel.org (any that received above backport)
URL: https://bugzilla.kernel.org/show_bug.cgi?id=98501
2015-05-21 09:14:25 +10:00
Shaohua Li
487696957e raid5: fix broken async operation chain
ops_run_reconstruct6() doesn't correctly chain asyn operations. The tx returned
by async_gen_syndrome should be added as the dependent tx of next stripe.

The issue is introduced by commit 59fc630b8b
    RAID5: batch adjacent full stripe write

Reported-and-tested-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-05-21 09:14:20 +10:00
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.
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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.
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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
Jens Axboe
dac56212e8 bio: skip atomic inc/dec of ->bi_cnt for most use cases
Struct bio has a reference count that controls when it can be freed.
Most uses cases is allocating the bio, which then returns with a
single reference to it, doing IO, and then dropping that single
reference. We can remove this atomic_dec_and_test() in the completion
path, if nobody else is holding a reference to the bio.

If someone does call bio_get() on the bio, then we flag the bio as
now having valid count and that we must properly honor the reference
count when it's being put.

Tested-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-05 13:32:49 -06:00
Jens Axboe
c4cf5261f8 bio: skip atomic inc/dec of ->bi_remaining for non-chains
Struct bio has an atomic ref count for chained bio's, and we use this
to know when to end IO on the bio. However, most bio's are not chained,
so we don't need to always introduce this atomic operation as part of
ending IO.

Add a helper to elevate the bi_remaining count, and flag the bio as
now actually needing the decrement at end_io time. Rename the field
to __bi_remaining to catch any current users of this doing the
incrementing manually.

For high IOPS workloads, this reduces the overhead of bio_endio()
substantially.

Tested-by: Robert Elliott <elliott@hp.com>
Acked-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-05 13:32:47 -06:00
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 #1 but not for #2.  However, we
cannot just reinstate the check as it'd mask a serious bug in the IO
completion case #2 -- no in-flight request should have an uninitialized
request_queue (basic block layer refcounting _should_ ensure this).

The NULL pointer seen for case #1 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.
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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).
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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
Dan Ehrenberg
644bda6f34 dm table: fall back to getting device using name_to_dev_t()
If a device is used as the root filesystem, it can't be built
off of devices which are within the root filesystem (just like
command line arguments to root=).  For this reason, Linux has a
pseudo-filesystem for root= and MD initialization (based on the
function name_to_dev_t) which handles different ways of specifying
devices including PARTUUID and major:minor.

Switch to using name_to_dev_t() in dm_get_device().  Rather than
having DM assume that all things which are not major:minor are paths in
an already-mounted filesystem, change dm_get_device() to first attempt
to look up the device in the filesystem, and if not found it will fall
back to using name_to_dev_t().

In terms of backwards compatibility, there are some cases where
behavior will be different:
- If you have a file in the current working directory named 1:2 and
  you initialze DM there, then it will try to use that file rather
  than the disk with that major:minor pair as a backing device.
- Similarly for other bdev types which name_to_dev_t() knows how to
  interpret, the previous behavior was to repeatedly check for the
  existence of the file (e.g., while waiting for rootfs to come up)
  but the new behavior is to use the name_to_dev_t() interpretation.
  For example, if you have a file named /dev/ubiblock0_0 which is
  a symlink to /dev/sda3, but it is not yet present when DM starts
  to initialize, then the name_to_dev_t() interpretation will take
  precedence.

These incompatibilities would only show up in really strange setups
with bad practices so we shouldn't have to worry about them.

Signed-off-by: Dan Ehrenberg <dehrenberg@chromium.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:19 -04:00
Mike Snitzer
17e149b8f7 dm: add 'use_blk_mq' module param and expose in per-device ro sysfs attr
Request-based DM's blk-mq support defaults to off; but a user can easily
change the default using the dm_mod.use_blk_mq module/boot option.

Also, you can check what mode a given request-based DM device is using
with: cat /sys/block/dm-X/dm/use_blk_mq

This change enabled further cleanup and reduced work (e.g. the
md->io_pool and md->rq_pool isn't created if using blk-mq).

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:17 -04:00
Mike Snitzer
022333427a dm: optimize dm_mq_queue_rq to _not_ use kthread if using pure blk-mq
dm_mq_queue_rq() is in atomic context so care must be taken to not
sleep -- as such GFP_ATOMIC is used for the md->bs bioset allocations
and dm-mpath's call to blk_get_request().  In the future the bioset
allocations will hopefully go away (by removing support for partial
completions of bios in a cloned request).

Also prepare for supporting DM blk-mq ontop of old-style request_fn
device(s) if a new dm-mod 'use_blk_mq' parameter is set.  The kthread
will still be used to queue work if blk-mq is used ontop of old-style
request_fn device(s).

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:17 -04:00
Mike Snitzer
bfebd1cdb4 dm: add full blk-mq support to request-based DM
Commit e5863d9ad ("dm: allocate requests in target when stacking on
blk-mq devices") served as the first step toward fully utilizing blk-mq
in request-based DM -- it enabled stacking an old-style (request_fn)
request_queue ontop of the underlying blk-mq device(s).  That first step
didn't improve performance of DM multipath ontop of fast blk-mq devices
(e.g. NVMe) because the top-level old-style request_queue was severely
limited by the queue_lock.

The second step offered here enables stacking a blk-mq request_queue
ontop of the underlying blk-mq device(s).  This unlocks significant
performance gains on fast blk-mq devices, Keith Busch tested on his NVMe
testbed and offered this really positive news:

 "Just providing a performance update. All my fio tests are getting
  roughly equal performance whether accessed through the raw block
  device or the multipath device mapper (~470k IOPS). I could only push
  ~20% of the raw iops through dm before this conversion, so this latest
  tree is looking really solid from a performance standpoint."

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Tested-by: Keith Busch <keith.busch@intel.com>
2015-04-15 12:10:16 -04:00
Mike Snitzer
0ce65797a7 dm: impose configurable deadline for dm_request_fn's merge heuristic
Otherwise, for sequential workloads, the dm_request_fn can allow
excessive request merging at the expense of increased service time.

Add a per-device sysfs attribute to allow the user to control how long a
request, that is a reasonable merge candidate, can be queued on the
request queue.  The resolution of this request dispatch deadline is in
microseconds (ranging from 1 to 100000 usecs), to set a 20us deadline:
  echo 20 > /sys/block/dm-7/dm/rq_based_seq_io_merge_deadline

The dm_request_fn's merge heuristic and associated extra accounting is
disabled by default (rq_based_seq_io_merge_deadline is 0).

This sysfs attribute is not applicable to bio-based DM devices so it
will only ever report 0 for them.

By allowing a request to remain on the queue it will block others
requests on the queue.  But introducing a short dequeue delay has proven
very effective at enabling certain sequential IO workloads on really
fast, yet IOPS constrained, devices to build up slightly larger IOs --
yielding 90+% throughput improvements.  Having precise control over the
time taken to wait for larger requests to build affords control beyond
that of waiting for certain IO sizes to accumulate (which would require
a deadline anyway).  This knob will only ever make sense with sequential
IO workloads and the particular value used is storage configuration
specific.

Given the expected niche use-case for when this knob is useful it has
been deemed acceptable to expose this relatively crude method for
crafting optimal IO on specific storage -- especially given the solution
is simple yet effective.  In the context of DM multipath, it is
advisable to tune this sysfs attribute to a value that offers the best
performance for the common case (e.g. if 4 paths are expected active,
tune for that; if paths fail then performance may be slightly reduced).

Alternatives were explored to have request-based DM autotune this value
(e.g. if/when paths fail) but they were quickly deemed too fragile and
complex to warrant further design and development time.  If this problem
proves more common as faster storage emerges we'll have to look at
elevating a generic solution into the block core.

Tested-by: Shiva Krishna Merla <shivakrishna.merla@netapp.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:15 -04:00
Mike Snitzer
b898320d68 dm sysfs: introduce ability to add writable attributes
Add DM_ATTR_RW() macro and establish .store method in dm_sysfs_ops.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:15 -04:00
Mike Snitzer
de3ec86dff dm: don't start current request if it would've merged with the previous
Request-based DM's dm_request_fn() is so fast to pull requests off the
queue that steps need to be taken to promote merging by avoiding request
processing if it makes sense.

If the current request would've merged with previous request let the
current request stay on the queue longer.

Suggested-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:14 -04:00
Mike Snitzer
d548b34b06 dm: reduce the queue delay used in dm_request_fn from 100ms to 10ms
Commit 7eaceaccab ("block: remove per-queue plugging") didn't justify
DM's use of a 100ms delay; such an extended delay is a liability when
there is reason to re-kick the queue.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:13 -04:00
Mike Snitzer
9d1deb83d4 dm: don't schedule delayed run of the queue if nothing to do
In request-based DM's dm_request_fn(), if blk_peek_request() returns
NULL just return.  Avoids unnecessary blk_delay_queue().

Reported-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:13 -04:00
Mike Snitzer
9a0e609e3f dm: only run the queue on completion if congested or no requests pending
On really fast storage it can be beneficial to delay running the
request_queue to allow the elevator more opportunity to merge requests.

Otherwise, it has been observed that requests are being sent to
q->request_fn much quicker than is ideal on IOPS-bound backends.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:12 -04:00
Mike Snitzer
ff36ab3458 dm: remove request-based logic from make_request_fn wrapper
The old dm_request() method used for q->make_request_fn had a branch for
request-based DM support but it isn't needed given that
dm_init_request_based_queue() sets it to the standard blk_queue_bio()
anyway.

Cleanup dm_init_md_queue() to be DM device-type agnostic and have
dm_setup_md_queue() properly finish queue setup based on DM device-type
(bio-based vs request-based).

A followup block patch can be made to remove the export for
blk_queue_bio() now that DM no longer calls it directly.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:08:48 -04:00
NeilBrown
47d68979cc md/raid0: fix bug with chunksize not a power of 2.
Since commit 20d0189b10
in v3.14-rc1 RAID0 has performed incorrect calculations
when the chunksize is not a power of 2.

This happens because "sector_div()" modifies its first argument, but
this wasn't taken into account in the patch.

So restore that first arg before re-using the variable.

Reported-by: Joe Landman <joe.landman@gmail.com>
Reported-by: Dave Chinner <david@fromorbit.com>
Fixes: 20d0189b10
Cc: stable@vger.kernel.org (3.14 and later).
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-10 15:36:31 +10:00
Gu Zheng
74672d069b md: fix md io stats accounting broken
Simon reported the md io stats accounting issue:
"
I'm seeing "iostat -x -k 1" print this after a RAID1 rebuild on 4.0-rc5.
It's not abnormal other than it's 3-disk, with one being SSD (sdc) and
the other two being write-mostly:

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
sda               0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00    0.00    0.00   0.00   0.00
sdb               0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00    0.00    0.00   0.00   0.00
sdc               0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00    0.00    0.00   0.00   0.00
md0               0.00     0.00    0.00    0.00     0.00     0.00     0.00   345.00    0.00    0.00    0.00   0.00 100.00
md2               0.00     0.00    0.00    0.00     0.00     0.00     0.00 58779.00    0.00    0.00    0.00   0.00 100.00
md1               0.00     0.00    0.00    0.00     0.00     0.00     0.00    12.00    0.00    0.00    0.00   0.00 100.00
"
The cause is commit "18c0b223cf9901727ef3b02da6711ac930b4e5d4" uses the
generic_start_io_acct to account the disk stats rather than the open code,
but it also introduced the increase to .in_flight[rw] which is needless to
md. So we re-use the open code here to fix it.

Reported-by: Simon Kirby <sim@hostway.ca>
Cc: <stable@vger.kernel.org> 3.19
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-08 12:53:00 +10:00
Mike Snitzer
d56b9b28a4 dm: remove request-based DM queue's lld_busy_fn hook
DM multipath is the only caller of blk_lld_busy() -- which calls a
queue's lld_busy_fn hook.  Request-based DM doesn't support stacking
multipath devices so there is no reason to register the lld_busy_fn hook
on a multipath device's queue using blk_queue_lld_busy().

As such, remove functions dm_lld_busy and dm_table_any_busy_target.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-03-31 12:03:49 -04:00
Mike Snitzer
52b09914af dm: remove unnecessary wrapper around blk_lld_busy
There is no need for DM to export a wrapper around the already exported
blk_lld_busy().

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-03-31 12:03:49 -04:00
Mike Snitzer
09c2d53101 dm: rename __dm_get_reserved_ios() helper to __dm_get_module_param()
__dm_get_module_param() could be useful for future DM module parameters
besides those related to "reserved_ios".

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-03-31 12:03:49 -04:00
Joe Thornber
e65ff8703f dm cache policy mq: try not to writeback data that changed in the last second
Writeback takes out a lock on the cache block, so will increase the
latency for any concurrent io.

This patch works by placing 2 sentinel objects on each level of the
multiqueues.  Every WRITEBACK_PERIOD the oldest sentinel gets moved to
the newest end of the queue level.

When looking for writeback work:
  if less than 25% of the cache is clean:
    we select the oldest object with the lowest hit count
  otherwise:
    we select the oldest object that is not past a writeback sentinel.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-03-31 12:03:48 -04:00
Joe Thornber
fdecee3224 dm cache policy mq: remove unused generation member of struct entry
Remove to stop wasting memory.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-03-31 12:03:48 -04:00
Joe Thornber
3e45c91e5c dm cache policy mq: track entries hit this 'tick' via sentinel objects
A sentinel object is placed on each level of the multiqueues.  When an
object is hit it is requeued behind the sentinel.  When the tick is
incremented we iterate through all objects behind the sentinel and
update the hit_count, then reposition the sentinel at the very back.

This saves memory by avoiding tracking the tick explicitly for every
struct entry object in the multiqueues.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-03-31 12:03:48 -04:00
Joe Thornber
c74ffc5c63 dm cache policy mq: remove queue_shift_down()
queue_shift_down() didn't adjust the hit_counts to the new levels, so it
just had the effect of scrambling levels.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-03-31 12:03:48 -04:00
Joe Thornber
75da39bf25 dm cache policy mq: keep track of the number of entries in a multiqueue
Small optimisation, now queue_empty() doesn't need to walk all levels of
the multiqueue.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-03-31 12:03:48 -04:00
Mike Snitzer
ac1f9ef211 dm log userspace: split flush_entry_pool to be per dirty-log
Use a single slab cache to allocate a mempool for each dirty-log.
This _should_ eliminate DM's need for io_schedule_timeout() in
mempool_alloc(); so io_schedule() should be sufficient now.

Also, rename struct flush_entry to dm_dirty_log_flush_entry to allow
KMEM_CACHE() to create a meaningful global name for the slab cache.

Also, eliminate some holes in struct log_c by rearranging members.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Heinz Mauelshagen <heinzm@redhat.com>
2015-03-31 12:03:47 -04:00
Linus Torvalds
be8a9bc633 . Fix DM core device cleanup regression -- due to a latent race that was
exposed by the bdi changes that were introduced during the 4.0 merge.
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Merge tag 'dm-4.0-fix-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fix from Mike Snitzer:
 "Fix DM core device cleanup regression -- due to a latent race that was
  exposed by the bdi changes that were introduced during the 4.0 merge"

* tag 'dm-4.0-fix-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm: fix add_disk() NULL pointer due to race with free_dev()
2015-03-26 14:53:47 -07:00
Goldwyn Rodrigues
124eb761ed md: Fix bitmap offset calculations
The calculations of bitmap offset is incorrect with respect to bits to bytes
conversion.

Also, remove an irrelevant duplicate message.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-03-25 13:07:55 +11:00
Mike Snitzer
63a4f065ec dm: fix add_disk() NULL pointer due to race with free_dev()
Commit c4db59d31e ("fs: don't reassign dirty inodes to
default_backing_dev_info") exposed DM to a latent race in free_dev() vs
add_disk() in relation to management of the device's minor number.

Fix this by refactoring free_dev() to match cleanup order of the
alloc_dev() error path.  Move cleanup of the gendisk, queue, and bdev
to _before_ the cleanup of the idr managed minor number.

Also, purely due to cleanup that fell out during the free_dev() audit:
- adjust dm_blk_close() to access the gendisk's private_data under
  the _minor_lock spinlock.
- move __dm_destroy()'s dm_get_live_table() call out from under the
  _minor_lock spinlock.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1202449

Reported-by: Zdenek Kabelac <zkabelac@redhat.com>
Reported-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-03-23 18:14:00 -04:00
Linus Torvalds
1b717b1af5 One fix for md in 4.0-rc4
Regression in recent patch causes crash on error path.
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Merge tag 'md/4.0-rc4-fix' of git://neil.brown.name/md

Pull bugfix for md from Neil Brown:
 "One fix for md in 4.0-rc4

  Regression in recent patch causes crash on error path"

* tag 'md/4.0-rc4-fix' of git://neil.brown.name/md:
  md: fix problems with freeing private data after ->run failure.
2015-03-22 16:38:19 -07:00
Linus Torvalds
da6b9a2049 A handful of stable fixes for DM:
- fix thin target to always zero-fill reads to unprovisioned blocks
 - fix to interlock device destruction's suspend from internal suspends
 - fix 2 snapshot exception store handover bugs
 - fix dm-io to cope with DISCARD and WRITE_SAME capabilities changing
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Merge tag 'dm-4.0-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull devicemapper fixes from Mike Snitzer:
 "A handful of stable fixes for DM:
   - fix thin target to always zero-fill reads to unprovisioned blocks
   - fix to interlock device destruction's suspend from internal
     suspends
   - fix 2 snapshot exception store handover bugs
   - fix dm-io to cope with DISCARD and WRITE_SAME capabilities changing"

* tag 'dm-4.0-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm io: deal with wandering queue limits when handling REQ_DISCARD and REQ_WRITE_SAME
  dm snapshot: suspend merging snapshot when doing exception handover
  dm snapshot: suspend origin when doing exception handover
  dm: hold suspend_lock while suspending device during device deletion
  dm thin: fix to consistently zero-fill reads to unprovisioned blocks
2015-03-21 11:15:13 -07:00
kbuild test robot
09dd1af2e0 md/cluster: Communication Framework: fix semicolon.cocci warnings
drivers/md/md-cluster.c:328:2-3: Unneeded semicolon

 Removes unneeded semicolon.

Generated by: scripts/coccinelle/misc/semicolon.cocci

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-03-21 10:33:00 +11:00
kbuild test robot
6dc69c9c46 md: recover_bitmaps() can be static
drivers/md/md-cluster.c:190:6: sparse: symbol 'recover_bitmaps' was not declared. Should it be static?

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-03-21 10:33:00 +11:00
Goldwyn Rodrigues
fa8259da0e md: Fix stray --cluster-confirm crash
A --cluster-confirm without an --add (by another node) can
crash the kernel.

Fix it by guarding it using a state.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-03-21 10:33:00 +11:00
NeilBrown
0c35bd4723 md: fix problems with freeing private data after ->run failure.
If ->run() fails, it can either free the data structures it
allocated, or leave that task to ->free() which will be called
on failures.

However:
  md.c calls ->free() even if ->private_data is NULL, which
     causes problems in some personalities.
  raid0.c frees the data, but doesn't clear ->private_data,
     which will become a problem when we fix md.c

So better fix both these issues at once.

Reported-by: Richard W.M. Jones <rjones@redhat.com>
Fixes: 5aa61f427e
URL: https://bugzilla.kernel.org/show_bug.cgi?id=94381
Signed-off-by: NeilBrown <neilb@suse.de>
2015-03-21 09:40:36 +11:00
Stephen Rothwell
3b0e6aacbf md/bitmap: use sector_div for sector_t divisions
neilb: modified to not corrupt ->resync_max_sectors.

sector_div usage fixed by Guoqing Jiang <gqjiang@suse.com>

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-03-04 13:08:16 +11:00
NeilBrown
935f3d4fc6 md/bitmap: fix incorrect DIV_ROUND_UP usage.
DIV_ROUTND_UP doesn't work on "long long", - and it should be
sector_t anyway.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-03-04 12:54:29 +11:00
Darrick J. Wong
e5db29806b dm io: deal with wandering queue limits when handling REQ_DISCARD and REQ_WRITE_SAME
Since it's possible for the discard and write same queue limits to
change while the upper level command is being sliced and diced, fix up
both of them (a) to reject IO if the special command is unsupported at
the start of the function and (b) read the limits once and let the
commands error out on their own if the status happens to change.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-02-27 14:53:32 -05:00
Mikulas Patocka
09ee96b214 dm snapshot: suspend merging snapshot when doing exception handover
The "dm snapshot: suspend origin when doing exception handover" commit
fixed a exception store handover bug associated with pending exceptions
to the "snapshot-origin" target.

However, a similar problem exists in snapshot merging.  When snapshot
merging is in progress, we use the target "snapshot-merge" instead of
"snapshot-origin".  Consequently, during exception store handover, we
must find the snapshot-merge target and suspend its associated
mapped_device.

To avoid lockdep warnings, the target must be suspended and resumed
without holding _origins_lock.

Introduce a dm_hold() function that grabs a reference on a
mapped_device, but unlike dm_get(), it doesn't crash if the device has
the DMF_FREEING flag set, it returns an error in this case.

In snapshot_resume() we grab the reference to the origin device using
dm_hold() while holding _origins_lock (_origins_lock guarantees that the
device won't disappear).  Then we release _origins_lock, suspend the
device and grab _origins_lock again.

NOTE to stable@ people:
When backporting to kernels 3.18 and older, use dm_internal_suspend and
dm_internal_resume instead of dm_internal_suspend_fast and
dm_internal_resume_fast.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-02-27 14:53:16 -05:00
Mikulas Patocka
b735fede8d dm snapshot: suspend origin when doing exception handover
In the function snapshot_resume we perform exception store handover.  If
there is another active snapshot target, the exception store is moved
from this target to the target that is being resumed.

The problem is that if there is some pending exception, it will point to
an incorrect exception store after that handover, causing a crash due to
dm-snap-persistent.c:get_exception()'s BUG_ON.

This bug can be triggered by repeatedly changing snapshot permissions
with "lvchange -p r" and "lvchange -p rw" while there are writes on the
associated origin device.

To fix this bug, we must suspend the origin device when doing the
exception store handover to make sure that there are no pending
exceptions:
- introduce _origin_hash that keeps track of dm_origin structures.
- introduce functions __lookup_dm_origin, __insert_dm_origin and
  __remove_dm_origin that manipulate the origin hash.
- modify snapshot_resume so that it calls dm_internal_suspend_fast() and
  dm_internal_resume_fast() on the origin device.

NOTE to stable@ people:

When backporting to kernels 3.12-3.18, use dm_internal_suspend and
dm_internal_resume instead of dm_internal_suspend_fast and
dm_internal_resume_fast.

When backporting to kernels older than 3.12, you need to pick functions
dm_internal_suspend and dm_internal_resume from the commit
fd2ed4d252.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-02-27 14:49:47 -05:00
Mikulas Patocka
ab7c7bb6f4 dm: hold suspend_lock while suspending device during device deletion
__dm_destroy() must take the suspend_lock so that its presuspend and
postsuspend calls do not race with an internal suspend.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-02-27 14:09:23 -05:00
Joe Thornber
5f027a3bf1 dm thin: fix to consistently zero-fill reads to unprovisioned blocks
It was always intended that a read to an unprovisioned block will return
zeroes regardless of whether the pool is in read-only or read-write
mode.  thin_bio_map() was inconsistent with its handling of such reads
when the pool is in read-only mode, it now properly zero-fills the bios
it returns in response to unprovisioned block reads.

Eliminate thin_bio_map()'s special read-only mode handling of -ENODATA
and just allow the IO to be deferred to the worker which will result in
pool->process_bio() handling the IO (which already properly zero-fills
reads to unprovisioned blocks).

Reported-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-02-27 09:59:12 -05:00
NeilBrown
ba599aca52 md: fix error paths from bitmap_create.
Recent change to bitmap_create mishandles errors.
In particular a failure doesn't alway cause 'err' to be set.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-25 11:44:11 +11:00
NeilBrown
750f199ee8 md: mark some attributes as pre-alloc
Since __ATTR_PREALLOC was introduced in v3.19-rc1~78^2~18
it can now be used by md.

This ensure that writing to these sysfs attributes will never
block due to a memory allocation.
Such blocking could become a deadlock if mdmon is trying to
reconfigure an array after a failure prior to re-enabling writes.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-25 11:38:46 +11:00
Eric Mei
16d9cfab93 raid5: check faulty flag for array status during recovery.
When we have more than 1 drive failure, it's possible we start
rebuild one drive while leaving another faulty drive in array.
To determine whether array will be optimal after building, current
code only check whether a drive is missing, which could potentially
lead to data corruption. This patch is to add checking Faulty flag.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-25 11:38:26 +11:00
Tomáš Hodek
d1901ef099 md/raid1: fix read balance when a drive is write-mostly.
When a drive is marked write-mostly it should only be the
target of reads if there is no other option.

This behaviour was broken by

commit 9dedf60313
    md/raid1: read balance chooses idlest disk for SSD

which causes a write-mostly device to be *preferred* is some cases.

Restore correct behaviour by checking and setting
best_dist_disk and best_pending_disk rather than best_disk.

We only need to test one of these as they are both changed
from -1 or >=0 at the same time.

As we leave min_pending and best_dist unchanged, any non-write-mostly
device will appear better than the write-mostly device.

Reported-by: Tomáš Hodek <tomas.hodek@volny.cz>
Reported-by: Dark Penguin <darkpenguin@yandex.ru>
Signed-off-by: NeilBrown <neilb@suse.de>
Link: http://marc.info/?l=linux-raid&m=135982797322422
Fixes: 9dedf60313
Cc: stable@vger.kernel.org (3.6+)
2015-02-25 11:37:02 +11:00
Goldwyn Rodrigues
1aee41f637 Add new disk to clustered array
Algorithm:
1. Node 1 issues mdadm --manage /dev/mdX --add /dev/sdYY which issues
   ioctl(ADD_NEW_DISC with disc.state set to MD_DISK_CLUSTER_ADD)
2. Node 1 sends NEWDISK with uuid and slot number
3. Other nodes issue kobject_uevent_env with uuid and slot number
(Steps 4,5 could be a udev rule)
4. In userspace, the node searches for the disk, perhaps
   using blkid -t SUB_UUID=""
5. Other nodes issue either of the following depending on whether the disk
   was found:
   ioctl(ADD_NEW_DISK with disc.state set to MD_DISK_CANDIDATE and
	 disc.number set to slot number)
   ioctl(CLUSTERED_DISK_NACK)
6. Other nodes drop lock on no-new-devs (CR) if device is found
7. Node 1 attempts EX lock on no-new-devs
8. If node 1 gets the lock, it sends METADATA_UPDATED after unmarking the disk
   as SpareLocal
9. If not (get no-new-dev lock), it fails the operation and sends METADATA_UPDATED
10. Other nodes understand if the device is added or not by reading the superblock again after receiving the METADATA_UPDATED message.

Signed-off-by: Lidong Zhong <lzhong@suse.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 09:59:07 -06:00
Goldwyn Rodrigues
7d49ffcfa3 Read from the first device when an area is resyncing
set choose_first true for cluster read in read balance when the area
is resyncing.

Signed-off-by: Lidong Zhong <lzhong@suse.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 09:59:07 -06:00
Goldwyn Rodrigues
589a1c4916 Suspend writes in RAID1 if within range
If there is a resync going on, all nodes must suspend writes to the
range. This is recorded in the suspend_info/suspend_list.

If there is an I/O within the ranges of any of the suspend_info,
should_suspend will return 1.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 09:59:07 -06:00
Goldwyn Rodrigues
e59721ccdc Resync start/Finish actions
When a RESYNC_START message arrives, the node removes the entry
with the current slot number and adds the range to the
suspend_list.

Simlarly, when a RESYNC_FINISHED message is received, node clears
entry with respect to the bitmap number.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 09:59:07 -06:00
Goldwyn Rodrigues
965400eb61 Send RESYNCING while performing resync start/stop
When a resync is initiated, RESYNCING message is sent to all active
nodes with the range (lo,hi). When the resync is over, a RESYNCING
message is sent with (0,0). A high sector value of zero indicates
that the resync is over.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 09:59:06 -06:00
Goldwyn Rodrigues
1d7e3e9611 Reload superblock if METADATA_UPDATED is received
Re-reads the devices by invalidating the cache.
Since we don't write to faulty devices, this is detected using
events recorded in the devices. If it is old as compared to the mddev
mark it is faulty.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 09:59:06 -06:00
Goldwyn Rodrigues
293467aa1f metadata_update sends message to other nodes
- request to send a message
   - make changes to superblock
   - send messages telling everyone that the superblock has changed
   - other nodes all read the superblock
   - other nodes all ack the messages
   - updating node release the "I'm sending a message" resource.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 09:59:06 -06:00
Goldwyn Rodrigues
601b515c5d Communication Framework: Sending functions
The sending part is split in two functions to make sure
atomicity of the operations, such as the MD superblock update.

Signed-off-by: Lidong Zhong <lzhong@suse.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 09:59:06 -06:00
Goldwyn Rodrigues
4664680c38 Communication Framework: Receiving
1. receive status

   sender                         receiver                   receiver
   ACK:CR                          ACK:CR                     ACK:CR

2. sender get EX of TOKEN
   sender get EX of MESSAGE
   sender                          receiver                   receiver
   TOKEN:EX                         ACK:CR                     ACK:CR
   MESSAGE:EX
   ACK:CR

3. sender write LVB.
   sender down-convert MESSAGE from EX to CR
   sender try to get EX of ACK
   [ wait until all receiver has *processed* the MESSAGE ]

                                     [ triggered by bast of ACK ]
                                     receiver get CR of MESSAGE
                                     receiver read LVB
                                     receiver processes the message
				     [ wait finish ]
                                     receiver release ACK

   sender                         receiver                   receiver
   TOKEN:EX                       MESSAGE:CR                 MESSAGE:CR
   MESSAGE:CR
   ACK:EX

4. sender down-convert ACK from EX to CR
   sender release MESSAGE
   sender release TOKEN
				  receiver upconvert to EX of MESSAGE
                                  receiver get CR of ACK
				  receiver release MESSAGE

   sender                        receiver                   receiver
   ACK:CR                         ACK:CR                     ACK:CR

Signed-off-by: Lidong Zhong <lzhong@suse.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 09:59:06 -06:00
Goldwyn Rodrigues
4b26a08af9 Perform resync for cluster node failure
If bitmap_copy_slot returns hi>0, we need to perform resync.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 09:59:06 -06:00
Goldwyn Rodrigues
e94987db2e Initiate recovery on node failure
The DLM informs us in case of node failure with the DLM slot number.
cluster_info->recovery_map sets the bit corresponding to the slot number
and wakes up the recovery thread.

The recovery thread:
1. Derives the slot number from the recovery_map
2. Locks the bitmap corresponding to the slot
3. Copies the set bits to the node-local bitmap

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 09:59:05 -06:00
Goldwyn Rodrigues
11dd35daaa Copy set bits from another slot
bitmap_copy_from_slot reads the bitmap from the slot mentioned.
It then copies the set bits to the node local bitmap.

This is helper function for the resync operation on node failure.

bitmap_set_memory_bits() currently assumes it is only run at startup and that
they bitmap is currently empty.  So if it finds that a region is already
marked as dirty, it won't mark it dirty again. Change bitmap_set_memory_bits()
to always set the NEEDED_MASK bit if 'needed' is set.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 09:59:05 -06:00
Goldwyn Rodrigues
f9209a3235 bitmap_create returns bitmap pointer
This is done to have multiple bitmaps open at the same time.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 09:57:57 -06:00
Goldwyn Rodrigues
96ae923ab6 Gather on-going resync information of other nodes
When a node joins, it does not know of other nodes performing resync.
So, each node keeps the resync information in it's LVB. When a new
node joins, it reads the LVB of each "online" bitmap.

[TODO] The new node attempts to get the PW lock on other bitmap, if
it is successful, it reads the bitmap and performs the resync (if
required) on it's behalf.

If the node does not get the PW, it requests CR and reads the LVB
for the resync information.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 07:30:11 -06:00
Goldwyn Rodrigues
54519c5f4b Lock bitmap while joining the cluster
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 07:30:11 -06:00
Goldwyn Rodrigues
b97e92574c Use separate bitmaps for each nodes in the cluster
On-disk format:

0                    4k                     8k                    12k
-------------------------------------------------------------------
| idle                | md super            | bm super [0] + bits |
| bm bits[0, contd]   | bm super[1] + bits  | bm bits[1, contd]   |
| bm super[2] + bits  | bm bits [2, contd]  | bm super[3] + bits  |
| bm bits [3, contd]  |                     |                     |

Bitmap super has a field nodes, which defines the maximum number
of nodes the device can use. While reading the bitmap super, if
the cluster finds out that the number of nodes is > 0:
1. Requests the md-cluster module.
2. Calls md_cluster_ops->join(), which sets up clustering such as
   joining DLM lockspace.

Since the first time, the first bitmap is read. After the call
to the cluster_setup, the bitmap offset is adjusted and the
superblock is re-read. This also ensures the bitmap is read
the bitmap lock (when bitmap lock is introduced in later patches)

Questions:
1. cluster name is repeated in all bitmap supers. Is that okay?

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 07:30:11 -06:00
Goldwyn Rodrigues
cf921cc19c Add node recovery callbacks
DLM offers callbacks when a node fails and the lock remastery
is performed:

1. recover_prep: called when DLM discovers a node is down
2. recover_slot: called when DLM identifies the node and recovery
		can start
3. recover_done: called when all nodes have completed recover_slot

recover_slot() and recover_done() are also called when the node joins
initially in order to inform the node with its slot number. These slot
numbers start from one, so we deduct one to make it start with zero
which the cluster-md code uses.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 07:30:11 -06:00
Goldwyn Rodrigues
ca8895d9bb Return MD_SB_CLUSTERED if mddev is clustered
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 07:28:43 -06:00
Goldwyn Rodrigues
c4ce867fda Introduce md_cluster_info
md_cluster_info stores the cluster information in the MD device.

The join() is called when mddev detects it is a clustered device.
The main responsibilities are:
	1. Setup a DLM lockspace
	2. Setup all initial locks such as super block locks and bitmap lock (will come later)

The leave() clears up the lockspace and all the locks held.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 07:28:42 -06:00
Goldwyn Rodrigues
edb39c9ded Introduce md_cluster_operations to handle cluster functions
This allows dynamic registering of cluster hooks.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 07:28:42 -06:00
Goldwyn Rodrigues
47741b7ca7 DLM lock and unlock functions
A dlm_lock_resource is a structure which contains all information
required for locking using DLM. The init function allocates the
lock and acquires the lock in NL mode. The unlock function
converts the lock resource to NL mode. This is done to preserve
LVB and for faster processing of locks. The lock resource is
DLM unlocked only in the lockres_free function, which is the end
of life of the lock resource.

Signed-off-by: Lidong Zhong <lzhong@suse.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 07:28:42 -06:00
Goldwyn Rodrigues
8e854e9cfd Create a separate module for clustering support
Tagged as EXPERIMENTAL for now.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 07:28:42 -06:00
Goldwyn Rodrigues
183bdf5106 Add number of nodes to bitmap structure for clustering
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 07:28:30 -06:00
Linus Torvalds
a911dcdba1 - Significant dm-crypt CPU scalability performance improvements thanks
to changes that enable effective use of an unbound workqueue across
   all available CPUs.  A large battery of tests were performed to
   validate these changes, summary of results is available here:
   https://www.redhat.com/archives/dm-devel/2015-February/msg00106.html
 
 - A few additional stable fixes (to DM core, dm-snapshot and dm-mirror)
   and a small fix to the dm-space-map-disk.
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Merge tag 'dm-3.20-changes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull more device mapper changes from Mike Snitzer:

- Significant dm-crypt CPU scalability performance improvements thanks
  to changes that enable effective use of an unbound workqueue across
  all available CPUs.  A large battery of tests were performed to
  validate these changes, summary of results is available here:
  https://www.redhat.com/archives/dm-devel/2015-February/msg00106.html

- A few additional stable fixes (to DM core, dm-snapshot and dm-mirror)
  and a small fix to the dm-space-map-disk.

* tag 'dm-3.20-changes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm snapshot: fix a possible invalid memory access on unload
  dm: fix a race condition in dm_get_md
  dm crypt: sort writes
  dm crypt: add 'submit_from_crypt_cpus' option
  dm crypt: offload writes to thread
  dm crypt: remove unused io_pool and _crypt_io_pool
  dm crypt: avoid deadlock in mempools
  dm crypt: don't allocate pages for a partial request
  dm crypt: use unbound workqueue for request processing
  dm io: reject unsupported DISCARD requests with EOPNOTSUPP
  dm mirror: do not degrade the mirror on discard error
  dm space map disk: fix sm_disk_count_is_more_than_one()
2015-02-21 13:28:45 -08:00
Linus Torvalds
b11a278397 Merge branch 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild
Pull kconfig updates from Michal Marek:
 "Yann E Morin was supposed to take over kconfig maintainership, but
  this hasn't happened.  So I'm sending a few kconfig patches that I
  collected:

   - Fix for missing va_end in kconfig
   - merge_config.sh displays used if given too few arguments
   - s/boolean/bool/ in Kconfig files for consistency, with the plan to
     only support bool in the future"

* 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
  kconfig: use va_end to match corresponding va_start
  merge_config.sh: Display usage if given too few arguments
  kconfig: use bool instead of boolean for type definition attributes
2015-02-19 10:36:45 -08:00
Mikulas Patocka
22aa66a3ee dm snapshot: fix a possible invalid memory access on unload
When the snapshot target is unloaded, snapshot_dtr() waits until
pending_exceptions_count drops to zero.  Then, it destroys the snapshot.
Therefore, the function that decrements pending_exceptions_count
should not touch the snapshot structure after the decrement.

pending_complete() calls free_pending_exception(), which decrements
pending_exceptions_count, and then it performs up_write(&s->lock) and it
calls retry_origin_bios() which dereferences  s->origin.  These two
memory accesses to the fields of the snapshot may touch the dm_snapshot
struture after it is freed.

This patch moves the call to free_pending_exception() to the end of
pending_complete(), so that the snapshot will not be destroyed while
pending_complete() is in progress.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-02-18 09:41:54 -05:00
Mikulas Patocka
2bec1f4a88 dm: fix a race condition in dm_get_md
The function dm_get_md finds a device mapper device with a given dev_t,
increases the reference count and returns the pointer.

dm_get_md calls dm_find_md, dm_find_md takes _minor_lock, finds the
device, tests that the device doesn't have DMF_DELETING or DMF_FREEING
flag, drops _minor_lock and returns pointer to the device. dm_get_md then
calls dm_get. dm_get calls BUG if the device has the DMF_FREEING flag,
otherwise it increments the reference count.

There is a possible race condition - after dm_find_md exits and before
dm_get is called, there are no locks held, so the device may disappear or
DMF_FREEING flag may be set, which results in BUG.

To fix this bug, we need to call dm_get while we hold _minor_lock. This
patch renames dm_find_md to dm_get_md and changes it so that it calls
dm_get while holding the lock.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-02-18 09:41:19 -05:00
Linus Torvalds
0d695d6d8b 3 bug md fixes for 3.20
yet-another-livelock in raid5, and a problem with write errors
 to 4K-block devices.
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Merge tag 'md/3.20-fixes' of git://neil.brown.name/md

Pull md bugfixes from Neil Brown:
 "Three bug md fixes for 3.20

  yet-another-livelock in raid5, and a problem with write errors to
  4K-block devices"

* tag 'md/3.20-fixes' of git://neil.brown.name/md:
  md/raid5: Fix livelock when array is both resyncing and degraded.
  md/raid10: round up to bdev_logical_block_size in narrow_write_error.
  md/raid1: round up to bdev_logical_block_size in narrow_write_error
2015-02-17 17:34:21 -08:00
NeilBrown
26ac107378 md/raid5: Fix livelock when array is both resyncing and degraded.
Commit a7854487cd:
  md: When RAID5 is dirty, force reconstruct-write instead of read-modify-write.

Causes an RCW cycle to be forced even when the array is degraded.
A degraded array cannot support RCW as that requires reading all data
blocks, and one may be missing.

Forcing an RCW when it is not possible causes a live-lock and the code
spins, repeatedly deciding to do something that cannot succeed.

So change the condition to only force RCW on non-degraded arrays.

Reported-by: Manibalan P <pmanibalan@amiindia.co.in>
Bisected-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Tested-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Fixes: a7854487cd
Cc: stable@vger.kernel.org (v3.7+)
2015-02-18 11:35:14 +11:00
Mikulas Patocka
b3c5fd3052 dm crypt: sort writes
Write requests are sorted in a red-black tree structure and are
submitted in the sorted order.

In theory the sorting should be performed by the underlying disk
scheduler, however, in practice the disk scheduler only accepts and
sorts a finite number of requests.  To allow the sorting of all
requests, dm-crypt needs to implement its own sorting.

The overhead associated with rbtree-based sorting is considered
negligible so it is not used conditionally.  Even on SSD sorting can be
beneficial since in-order request dispatch promotes lower latency IO
completion to the upper layers.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-16 11:11:15 -05:00
Mikulas Patocka
0f5d8e6ee7 dm crypt: add 'submit_from_crypt_cpus' option
Make it possible to disable offloading writes by setting the optional
'submit_from_crypt_cpus' table argument.

There are some situations where offloading write bios from the
encryption threads to a single thread degrades performance
significantly.

The default is to offload write bios to the same thread because it
benefits CFQ to have writes submitted using the same IO context.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-16 11:11:15 -05:00
Mikulas Patocka
dc2676210c dm crypt: offload writes to thread
Submitting write bios directly in the encryption thread caused serious
performance degradation.  On a multiprocessor machine, encryption requests
finish in a different order than they were submitted.  Consequently, write
requests would be submitted in a different order and it could cause severe
performance degradation.

Move the submission of write requests to a separate thread so that the
requests can be sorted before submitting.  But this commit improves
dm-crypt performance even without having dm-crypt perform request
sorting (in particular it enables IO schedulers like CFQ to sort more
effectively).

Note: it is required that a previous commit ("dm crypt: don't allocate
pages for a partial request") be applied before applying this patch.
Otherwise, this commit could introduce a crash.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-16 11:11:14 -05:00
Mikulas Patocka
94f5e0243c dm crypt: remove unused io_pool and _crypt_io_pool
The previous commit ("dm crypt: don't allocate pages for a partial
request") stopped using the io_pool slab mempool and backing
_crypt_io_pool kmem cache.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-16 11:11:13 -05:00
Mikulas Patocka
7145c241a1 dm crypt: avoid deadlock in mempools
Fix a theoretical deadlock introduced in the previous commit ("dm crypt:
don't allocate pages for a partial request").

The function crypt_alloc_buffer may be called concurrently.  If we allocate
from the mempool concurrently, there is a possibility of deadlock.  For
example, if we have mempool of 256 pages, two processes, each wanting
256, pages allocate from the mempool concurrently, it may deadlock in a
situation where both processes have allocated 128 pages and the mempool
is exhausted.

To avoid such a scenario we allocate the pages under a mutex.  In order
to not degrade performance with excessive locking, we try non-blocking
allocations without a mutex first and if that fails, we fallback to a
blocking allocations with a mutex.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-16 11:11:13 -05:00
Mikulas Patocka
cf2f1abfbd dm crypt: don't allocate pages for a partial request
Change crypt_alloc_buffer so that it only ever allocates pages for a
full request.  This is a prerequisite for the commit "dm crypt: offload
writes to thread".

This change simplifies the dm-crypt code at the expense of reduced
throughput in low memory conditions (where allocation for a partial
request is most useful).

Note: the next commit ("dm crypt: avoid deadlock in mempools") is needed
to fix a theoretical deadlock.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-16 11:11:12 -05:00
Mikulas Patocka
f3396c58fd dm crypt: use unbound workqueue for request processing
Use unbound workqueue by default so that work is automatically balanced
between available CPUs.  The original behavior of encrypting using the
same cpu that IO was submitted on can still be enabled by setting the
optional 'same_cpu_crypt' table argument.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-16 11:10:59 -05:00
NeilBrown
f04ebb0be7 md/raid10: round up to bdev_logical_block_size in narrow_write_error.
RAID10 version of earlier fix for RAID1.  We must never initiate
IO with sizes less that logical_block_size.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-16 14:51:54 +11:00
Nate Dailey
ab713cdc6f md/raid1: round up to bdev_logical_block_size in narrow_write_error
This modifies raid1's narrow_write_error to round up block_sectors to the
device's logical block size.

This prevents sd complaining about "Bad block number requested" for non-512-byte
sector disks.

Signed-off-by: Nate Dailey <nate.dailey@stratus.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-16 14:49:26 +11:00
Darrick J. Wong
37527b8692 dm io: reject unsupported DISCARD requests with EOPNOTSUPP
I created a dm-raid1 device backed by a device that supports DISCARD
and another device that does NOT support DISCARD with the following
dm configuration:

 #  echo '0 2048 mirror core 1 512 2 /dev/sda 0 /dev/sdb 0' | dmsetup create moo
 # lsblk -D
 NAME         DISC-ALN DISC-GRAN DISC-MAX DISC-ZERO
 sda                 0        4K       1G         0
 `-moo (dm-0)        0        4K       1G         0
 sdb                 0        0B       0B         0
 `-moo (dm-0)        0        4K       1G         0

Notice that the mirror device /dev/mapper/moo advertises DISCARD
support even though one of the mirror halves doesn't.

If I issue a DISCARD request (via fstrim, mount -o discard, or ioctl
BLKDISCARD) through the mirror, kmirrord gets stuck in an infinite
loop in do_region() when it tries to issue a DISCARD request to sdb.
The problem is that when we call do_region() against sdb, num_sectors
is set to zero because q->limits.max_discard_sectors is zero.
Therefore, "remaining" never decreases and the loop never terminates.

To fix this: before entering the loop, check for the combination of
REQ_DISCARD and no discard and return -EOPNOTSUPP to avoid hanging up
the mirror device.

This bug was found by the unfortunate coincidence of pvmove and a
discard operation in the RHEL 6.5 kernel; upstream is also affected.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-02-13 19:51:09 -05:00
Mikulas Patocka
f2ed51ac64 dm mirror: do not degrade the mirror on discard error
It may be possible that a device claims discard support but it rejects
discards with -EOPNOTSUPP.  It happens when using loopback on ext2/ext3
filesystem driven by the ext4 driver.  It may also happen if the
underlying devices are moved from one disk on another.

If discard error happens, we reject the bio with -EOPNOTSUPP, but we do
not degrade the array.

This patch fixes failed test shell/lvconvert-repair-transient.sh in the
lvm2 testsuite if the testsuite is extracted on an ext2 or ext3
filesystem and it is being driven by the ext4 driver.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-02-13 19:50:46 -05:00
Mike Snitzer
145b9006a0 dm space map disk: fix sm_disk_count_is_more_than_one()
dm_tm_shadow_block() is the only caller of
dm_sm_count_is_more_than_one() which only ever operates on a metadata
space-map.  So in practice, sm_disk_count_is_more_than_one() isn't
actually used (which explains why this bug never amounted to anything).

But fix sm_disk_count_is_more_than_one() to properly set *result and
return 0.

Reported-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-13 19:32:58 -05:00
Linus Torvalds
802ea9d864 - Most significant change this cycle is request-based DM now supports
stacking ontop of blk-mq devices.  This blk-mq support changes the
   model request-based DM uses for cloning a request to relying on
   calling blk_get_request() directly from the underlying blk-mq device.
   Early consumer of this code is Intel's emerging NVMe hardware; thanks
   to Keith Busch for working on, and pushing for, these changes.
 
 - A few other small fixes and cleanups across other DM targets.
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Merge tag 'dm-3.20-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper changes from Mike Snitzer:

 - The most significant change this cycle is request-based DM now
   supports stacking ontop of blk-mq devices.  This blk-mq support
   changes the model request-based DM uses for cloning a request to
   relying on calling blk_get_request() directly from the underlying
   blk-mq device.

   An early consumer of this code is Intel's emerging NVMe hardware;
   thanks to Keith Busch for working on, and pushing for, these changes.

 - A few other small fixes and cleanups across other DM targets.

* tag 'dm-3.20-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm: inherit QUEUE_FLAG_SG_GAPS flags from underlying queues
  dm snapshot: remove unnecessary NULL checks before vfree() calls
  dm mpath: simplify failure path of dm_multipath_init()
  dm thin metadata: remove unused dm_pool_get_data_block_size()
  dm ioctl: fix stale comment above dm_get_inactive_table()
  dm crypt: update url in CONFIG_DM_CRYPT help text
  dm bufio: fix time comparison to use time_after_eq()
  dm: use time_in_range() and time_after()
  dm raid: fix a couple integer overflows
  dm table: train hybrid target type detection to select blk-mq if appropriate
  dm: allocate requests in target when stacking on blk-mq devices
  dm: prepare for allocating blk-mq clone requests in target
  dm: submit stacked requests in irq enabled context
  dm: split request structure out from dm_rq_target_io structure
  dm: remove exports for request-based interfaces without external callers
2015-02-12 16:36:31 -08:00
Linus Torvalds
3e12cefbe1 Merge branch 'for-3.20/core' of git://git.kernel.dk/linux-block
Pull core block IO changes from Jens Axboe:
 "This contains:

   - A series from Christoph that cleans up and refactors various parts
     of the REQ_BLOCK_PC handling.  Contributions in that series from
     Dongsu Park and Kent Overstreet as well.

   - CFQ:
        - A bug fix for cfq for realtime IO scheduling from Jeff Moyer.
        - A stable patch fixing a potential crash in CFQ in OOM
          situations.  From Konstantin Khlebnikov.

   - blk-mq:
        - Add support for tag allocation policies, from Shaohua. This is
          a prep patch enabling libata (and other SCSI parts) to use the
          blk-mq tagging, instead of rolling their own.
        - Various little tweaks from Keith and Mike, in preparation for
          DM blk-mq support.
        - Minor little fixes or tweaks from me.
        - A double free error fix from Tony Battersby.

   - The partition 4k issue fixes from Matthew and Boaz.

   - Add support for zero+unprovision for blkdev_issue_zeroout() from
     Martin"

* 'for-3.20/core' of git://git.kernel.dk/linux-block: (27 commits)
  block: remove unused function blk_bio_map_sg
  block: handle the null_mapped flag correctly in blk_rq_map_user_iov
  blk-mq: fix double-free in error path
  block: prevent request-to-request merging with gaps if not allowed
  blk-mq: make blk_mq_run_queues() static
  dm: fix multipath regression due to initializing wrong request
  cfq-iosched: handle failure of cfq group allocation
  block: Quiesce zeroout wrapper
  block: rewrite and split __bio_copy_iov()
  block: merge __bio_map_user_iov into bio_map_user_iov
  block: merge __bio_map_kern into bio_map_kern
  block: pass iov_iter to the BLOCK_PC mapping functions
  block: add a helper to free bio bounce buffer pages
  block: use blk_rq_map_user_iov to implement blk_rq_map_user
  block: simplify bio_map_kern
  block: mark blk-mq devices as stackable
  block: keep established cmd_flags when cloning into a blk-mq request
  block: add blk-mq support to blk_insert_cloned_request()
  block: require blk_rq_prep_clone() be given an initialized clone request
  blk-mq: add tag allocation policy
  ...
2015-02-12 14:13:23 -08:00
Linus Torvalds
5d8e7fb691 md updates for 3.20
- assorted locking changes so that access to /proc/mdstat
    and much of /sys/block/mdXX/md/* is protected by a spinlock
    rather than a mutex and will never block indefinitely.
 
  - Make an 'if' condition in RAID5 - which has been implicated
    in recent bugs - more readable.
 
  - misc minor fixes
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Merge tag 'md/3.20' of git://neil.brown.name/md

Pull md updates from Neil Brown:

 - assorted locking changes so that access to /proc/mdstat
   and much of /sys/block/mdXX/md/* is protected by a spinlock
   rather than a mutex and will never block indefinitely.

 - Make an 'if' condition in RAID5 - which has been implicated
   in recent bugs - more readable.

 - misc minor fixes

* tag 'md/3.20' of git://neil.brown.name/md: (28 commits)
  md/raid10: fix conversion from RAID0 to RAID10
  md: wakeup thread upon rdev_dec_pending()
  md: make reconfig_mutex optional for writes to md sysfs files.
  md: move mddev_lock and related to md.h
  md: use mddev->lock to protect updates to resync_{min,max}.
  md: minor cleanup in safe_delay_store.
  md: move GET_BITMAP_FILE ioctl out from mddev_lock.
  md: tidy up set_bitmap_file
  md: remove unnecessary 'buf' from get_bitmap_file.
  md: remove mddev_lock from rdev_attr_show()
  md: remove mddev_lock() from md_attr_show()
  md/raid5: use ->lock to protect accessing raid5 sysfs attributes.
  md: remove need for mddev_lock() in md_seq_show()
  md/bitmap: protect clearing of ->bitmap by mddev->lock
  md: protect ->pers changes with mddev->lock
  md: level_store: group all important changes into one place.
  md: rename ->stop to ->free
  md: split detach operation out from ->stop.
  md/linear: remove rcu protections in favour of suspend/resume
  md: make merge_bvec_fn more robust in face of personality changes.
  ...
2015-02-12 11:05:49 -08:00
NeilBrown
53a6ab4d3f md/raid10: fix conversion from RAID0 to RAID10
A RAID0 array (like a LINEAR array) does not have a concept
of 'size' being the amount of each device that is in use.
Rather, as much of each device as is available is used.
So the 'size' is set to 0 and ignored.

RAID10 does have this concept and needs it to be set correctly.
So when we convert RAID0 to RAID10 we must determine the
'size' (that being the size of the first 'strip_zone' in the
RAID0), and set it correctly.

Reported-and-tested-by: Xiao Ni <xni@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-12 14:09:57 +11:00
Keith Busch
a4afe76b2b dm: inherit QUEUE_FLAG_SG_GAPS flags from underlying queues
A DM device must inherit the QUEUE_FLAG_SG_GAPS flags from its
underlying block devices' request queues.

This fixes problems when submitting cloned requests to multipathed
devices requiring virtually contiguous buffers.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-11 10:25:46 -05:00
Linus Torvalds
23e8fe2e16 Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU updates from Ingo Molnar:
 "The main RCU changes in this cycle are:

   - Documentation updates.

   - Miscellaneous fixes.

   - Preemptible-RCU fixes, including fixing an old bug in the
     interaction of RCU priority boosting and CPU hotplug.

   - SRCU updates.

   - RCU CPU stall-warning updates.

   - RCU torture-test updates"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits)
  rcu: Initialize tiny RCU stall-warning timeouts at boot
  rcu: Fix RCU CPU stall detection in tiny implementation
  rcu: Add GP-kthread-starvation checks to CPU stall warnings
  rcu: Make cond_resched_rcu_qs() apply to normal RCU flavors
  rcu: Optionally run grace-period kthreads at real-time priority
  ksoftirqd: Use new cond_resched_rcu_qs() function
  ksoftirqd: Enable IRQs and call cond_resched() before poking RCU
  rcutorture: Add more diagnostics in rcu_barrier() test failure case
  torture: Flag console.log file to prevent holdovers from earlier runs
  torture: Add "-enable-kvm -soundhw pcspk" to qemu command line
  rcutorture: Handle different mpstat versions
  rcutorture: Check from beginning to end of grace period
  rcu: Remove redundant rcu_batches_completed() declaration
  rcutorture: Drop rcu_torture_completed() and friends
  rcu: Provide rcu_batches_completed_sched() for TINY_RCU
  rcutorture: Use unsigned for Reader Batch computations
  rcutorture: Make build-output parsing correctly flag RCU's warnings
  rcu: Make _batches_completed() functions return unsigned long
  rcutorture: Issue warnings on close calls due to Reader Batch blows
  documentation: Fix smp typo in memory-barriers.txt
  ...
2015-02-09 14:28:42 -08:00
Markus Elfring
0c8f86322f dm snapshot: remove unnecessary NULL checks before vfree() calls
The vfree() function performs input parameter validation.
Thus the NULL pointer test around vfree() calls is not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09 13:06:49 -05:00
Johannes Thumshirn
ff658e9c1a dm mpath: simplify failure path of dm_multipath_init()
Currently the cleanup of all error cases are open-coded.  Introduce a
common exit path and labels.

Signed-off-by: Johannes Thumshirn <morbidrsa@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09 13:06:49 -05:00
Rickard Strandqvist
9cb1397d58 dm thin metadata: remove unused dm_pool_get_data_block_size()
The thin-pool target doesn't display the data block size as part of
its table status, unlike the dm-cache target, so there is no need for
dm_pool_get_data_block_size().

This was found using cppcheck.

Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09 13:06:49 -05:00
Junxiao Bi
88e2f901e7 dm ioctl: fix stale comment above dm_get_inactive_table()
dm_table_put() was replaced by dm_put_live_table().

Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09 13:06:48 -05:00
Loic Pefferkorn
cf35248768 dm crypt: update url in CONFIG_DM_CRYPT help text
Update the obsolete url in the CONFIG_DM_CRYPT help text.

Signed-off-by: Loic Pefferkorn <loic@loicp.eu>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09 13:06:48 -05:00
Asaf Vertz
f495339c44 dm bufio: fix time comparison to use time_after_eq()
To be future-proof and for better readability the time comparison
is modified to use time_after_eq() instead of plain, error-prone math.

Signed-off-by: Asaf Vertz <asaf.vertz@tandemg.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09 13:06:48 -05:00
Manuel Schölling
0f30af98cb dm: use time_in_range() and time_after()
To be future-proof and for better readability the time comparisons are modified
to use time_in_range() and time_after() instead of plain, error-prone math.

Signed-off-by: Manuel Schölling <manuel.schoelling@gmx.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09 13:06:48 -05:00
Dan Carpenter
3ca5a21a9c dm raid: fix a couple integer overflows
My static checker complains that if "num_raid_params" is UINT_MAX then
the "if (num_raid_params + 1 > argc) {" check doesn't work as intended.

The other change is that I moved the "if (argc != (num_raid_devs * 2))"
condition forward a few lines so it was before the call to
context_alloc().  If we had an integer overflow inside that function
then it would lead to an immediate crash.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09 13:06:48 -05:00
Mike Snitzer
65803c2059 dm table: train hybrid target type detection to select blk-mq if appropriate
Otherwise replacing the multipath target with the error target fails:
  device-mapper: ioctl: can't change device type after initial table load.

The error target was mistakenly considered to be target type
DM_TYPE_REQUEST_BASED rather than DM_TYPE_MQ_REQUEST_BASED even if the
target it was to replace was of type DM_TYPE_MQ_REQUEST_BASED.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09 13:06:47 -05:00
Mike Snitzer
e5863d9ad7 dm: allocate requests in target when stacking on blk-mq devices
For blk-mq request-based DM the responsibility of allocating a cloned
request is transfered from DM core to the target type.  Doing so
enables the cloned request to be allocated from the appropriate
blk-mq request_queue's pool (only the DM target, e.g. multipath, can
know which block device to send a given cloned request to).

Care was taken to preserve compatibility with old-style block request
completion that requires request-based DM _not_ acquire the clone
request's queue lock in the completion path.  As such, there are now 2
different request-based DM target_type interfaces:
1) the original .map_rq() interface will continue to be used for
   non-blk-mq devices -- the preallocated clone request is passed in
   from DM core.
2) a new .clone_and_map_rq() and .release_clone_rq() will be used for
   blk-mq devices -- blk_get_request() and blk_put_request() are used
   respectively from these hooks.

dm_table_set_type() was updated to detect if the request-based target is
being stacked on blk-mq devices, if so DM_TYPE_MQ_REQUEST_BASED is set.
DM core disallows switching the DM table's type after it is set.  This
means that there is no mixing of non-blk-mq and blk-mq devices within
the same request-based DM table.

[This patch was started by Keith and later heavily modified by Mike]

Tested-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09 13:06:47 -05:00
Keith Busch
466d89a6bc dm: prepare for allocating blk-mq clone requests in target
For blk-mq request-based DM the responsibility of allocating a cloned
request will be transfered from DM core to the target type.

To prepare for conditionally using this new model the original
request's 'special' now points to the dm_rq_target_io because the
clone is allocated later in the block layer rather than in DM core.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09 13:06:47 -05:00
Keith Busch
2eb6e1e3aa dm: submit stacked requests in irq enabled context
Switch to having request-based DM enqueue all prep'ed requests into work
processed by another thread.  This allows request-based DM to invoke
block APIs that assume interrupt enabled context (e.g. blk_get_request)
and is a prerequisite for adding blk-mq support to request-based DM.

The new kernel thread is only initialized for request-based DM devices.

multipath_map() is now always in irq enabled context so change multipath
spinlock (m->lock) locking to always disable interrupts.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09 13:06:47 -05:00
Mike Snitzer
1ae49ea2cf dm: split request structure out from dm_rq_target_io structure
Request-based DM support for blk-mq devices requires that
dm_rq_target_io structures not be allocated with an embedded request
structure.  The request-based DM target (e.g. dm-multipath) must
allocate the request from the blk-mq devices' request_queue using
blk_get_request().

The unfortunate side-effect of this change is old-style request-based DM
support will no longer use contiguous memory for the dm_rq_target_io and
request structures for each clone.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09 13:06:47 -05:00
Mike Snitzer
dbf9782c10 dm: remove exports for request-based interfaces without external callers
Remove exports for dm_dispatch_request, dm_requeue_unmapped_request,
and dm_kill_unmapped_request.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09 12:59:48 -05:00
Mike Snitzer
db507b3ffd dm: fix multipath regression due to initializing wrong request
Commit febf715 ("block: require blk_rq_prep_clone() be given an
initialized clone request") introduced a regression by calling
blk_rq_init() on the original request rather than the clone
request that is passed to setup_clone().

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Fixes: febf71588c ("block: require blk_rq_prep_clone() be given an initialized clone request")
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-09 10:46:08 -07:00
Hannes Reinecke
dfe15ac1c6 md: wakeup thread upon rdev_dec_pending()
After each call to rdev_dec_pending() we should wakeup the
md thread if the device is found to be faulty.
Otherwise we'll incur heavy delays on failing devices.

Signed-off-by: Neil Brown <nfbrown@suse.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
2015-02-06 09:32:57 +11:00
NeilBrown
6791875e2e md: make reconfig_mutex optional for writes to md sysfs files.
Rather than using mddev_lock() to take the reconfig_mutex
when writing to any md sysfs file, we only take mddev_lock()
in the particular _store() functions that require it.
Admittedly this is most, but it isn't all.

This also allows us to remove special-case handling for new_dev_store
(in md_attr_store).

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-06 09:32:56 +11:00
NeilBrown
5c47daf6e7 md: move mddev_lock and related to md.h
The one which is not inline (mddev_unlock) gets EXPORTed.

This makes the locking available to personality modules so that it
doesn't have to be imposed upon them.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-06 09:32:56 +11:00
NeilBrown
23da422b19 md: use mddev->lock to protect updates to resync_{min,max}.
There are interdependencies between these two sysfs attributes
and whether a resync is currently running.

Rather than depending on reconfig_mutex to ensure no races when
testing these interdependencies are met, use the spinlock.
This will allow the mutex to be remove from protecting this
code in a subsequent patch.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-06 09:32:56 +11:00
NeilBrown
1b30e66f5a md: minor cleanup in safe_delay_store.
There isn't really much room for races with ->safemode_delay.
But as I am trying to clean up any racy code and will soon
be removing reconfig_mutex protection from most _store()
functions:
 - only set mddev->safemode_delay once, to ensure no code
   can see an intermediate value
 - use safemode_timer to call md_safemode_timeout() rather than
   calling it directly, to ensure it never races with itself.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-06 09:32:56 +11:00
NeilBrown
4af1a04176 md: move GET_BITMAP_FILE ioctl out from mddev_lock.
It makes more sense to report bitmap_info->file, rather than
bitmap->file (the later is only available once the array is
active).

With that change, use mddev->lock to protect bitmap_info being
set to NULL, and we can call get_bitmap_file() without taking
the mutex.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-06 09:32:56 +11:00
NeilBrown
1e594bb24d md: tidy up set_bitmap_file
1/ delay setting mddev->bitmap_info.file until 'f' looks
   usable, so we don't have to unset it.
2/ Don't allow bitmap file to be set if bitmap_info.file
   is already set.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-06 09:32:56 +11:00
NeilBrown
f4ad3d38d4 md: remove unnecessary 'buf' from get_bitmap_file.
'buf' is only used because d_path fills from the end of the
buffer instead of from the start.
We don't need a separate buf to handle that, we just need to use
memmove() to move the string to the start.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-06 09:32:56 +11:00
NeilBrown
758bfc8abf md: remove mddev_lock from rdev_attr_show()
No rdev attributes need locking for 'show', though
state_show() might benefit from ensuring it sees a
consistent set of flags.

None even use rdev->mddev, so testing for it isn't really
needed and it certainly doesn't need to be held constant.

So improve state_show() and remove the locking.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-06 09:32:56 +11:00
NeilBrown
b7b17c9b67 md: remove mddev_lock() from md_attr_show()
Most attributes can be read safely without any locking.
A race might lead to a slightly out-dated value, but nothing wrong.

We already have locking in some places where needed.
All that remains is can_clear_show(), behind_writes_used_show()
and action_show() which are easily fixed.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-06 09:32:55 +11:00
NeilBrown
7b1485bab9 md/raid5: use ->lock to protect accessing raid5 sysfs attributes.
It is important that mddev->private isn't freed while
a sysfs attribute function is accessing it.

So use mddev->lock to protect the setting of ->private to NULL, and
take that lock when checking ->private for NULL and de-referencing it
in the sysfs access functions.

This only applies to the read ('show') side of access.  Write
access will be handled separately.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-06 09:32:55 +11:00
NeilBrown
f97fcad38f md: remove need for mddev_lock() in md_seq_show()
The only access in md_seq_show that could suffer from races
not protected by ->lock is walking the rdev list.
This can receive sufficient protection from 'rcu'.

So use rdev_for_each_rcu() and get rid of mddev_lock().

Now reading /proc/mdstat will never block in md_seq_show.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-06 09:32:55 +11:00
NeilBrown
978a7a47ca md/bitmap: protect clearing of ->bitmap by mddev->lock
This makes it safe to inspect the struct while holding only
the spinlock.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-06 09:32:55 +11:00
Linus Torvalds
59acf65776 Two fixes for md
1/ Another live lock, needs backporting
 2/ work-around false positive with new warnings.
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Merge tag 'md/3.19-fixes' of git://neil.brown.name/md

Pull two fixes for md from Neil Brown:

 - Another live lock, needs backporting

 - work-around false positive with new warnings.

* tag 'md/3.19-fixes' of git://neil.brown.name/md:
  md/bitmap: fix a might_sleep() warning.
  md/raid5: fix another livelock caused by non-aligned writes.
2015-02-03 19:54:57 -08:00
NeilBrown
36d091f475 md: protect ->pers changes with mddev->lock
->pers is already protected by ->reconfig_mutex, and
cannot possibly change when there are threads running or
outstanding IO.

However there are some places where we access ->pers
not in a thread or IO context, and where ->reconfig_mutex
is unnecessarily heavy-weight:  level_show and md_seq_show().

So protect all changes, and those accesses, with ->lock.
This is a step toward taking those accesses out from under
reconfig_mutex.

[Fixed missing "mddev->pers" -> "pers" conversion, thanks to
 Dan Carpenter <dan.carpenter@oracle.com>]

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-04 08:35:53 +11:00
NeilBrown
db721d32b7 md: level_store: group all important changes into one place.
Gather all the changes that can happen atomically and might
be relevant to other code into one place.  This will
make it easier to refine the locking.

Note that this puts quite a few things between mddev_detach()
and ->free().  Enabling this was the point of some recent patches.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-04 08:35:53 +11:00
NeilBrown
afa0f557cb md: rename ->stop to ->free
Now that the ->stop function only frees the private data,
rename is accordingly.

Also pass in the private pointer as an arg rather than using
mddev->private.  This flexibility will be useful in level_store().

Finally, don't clear ->private.  It doesn't make sense to clear
it seeing that isn't what we free, and it is no longer necessary
to clear ->private (it was some time ago before  ->to_remove was
introduced).

Setting ->to_remove in ->free() is a bit of a wart, but not a
big problem at the moment.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-04 08:35:52 +11:00
NeilBrown
5aa61f427e md: split detach operation out from ->stop.
Each md personality has a 'stop' operation which does two
things:
 1/ it finalizes some aspects of the array to ensure nothing
    is accessing the ->private data
 2/ it frees the ->private data.

All the steps in '1' can apply to all arrays and so can be
performed in common code.

This is useful as in the case where we change the personality which
manages an array (in level_store()), it would be helpful to do
step 1 early, and step 2 later.

So split the 'step 1' functionality out into a new mddev_detach().

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-04 08:35:52 +11:00
NeilBrown
3be260cc18 md/linear: remove rcu protections in favour of suspend/resume
The use of 'rcu' to protect accesses to ->private_data so that
the ->private_data could be updated predates the introduction
of mddev_suspend/mddev_resume.
These are a cleaner mechanism for providing stability while
swapping in a new ->private data - it is used by level_store()
to support changing of raid levels.

So get rid of the RCU stuff and just use mddev_suspend, mddev_resume.

As these function call ->quiesce(), we add an empty function for
linear just like for raid0.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-04 08:35:52 +11:00
NeilBrown
64590f45dd md: make merge_bvec_fn more robust in face of personality changes.
There is no locking around calls to merge_bvec_fn(), so
it is possible that calls which coincide with a level (or personality)
change could go wrong.

So create a central dispatch point for these functions and use
rcu_read_lock().
If the array is suspended, reject any merge that can be rejected.
If not, we know it is safe to call the function.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-04 08:35:52 +11:00
NeilBrown
5c675f83c6 md: make ->congested robust against personality changes.
There is currently no locking around calls to the 'congested'
bdi function.  If called at an awkward time while an array is
being converted from one level (or personality) to another, there
is a tiny chance of running code in an unreferenced module etc.

So add a 'congested' function to the md_personality operations
structure, and call it with appropriate locking from a central
'mddev_congested'.

When the array personality is changing the array will be 'suspended'
so no IO is processed.
If mddev_congested detects this, it simply reports that the
array is congested, which is a safe guess.
As mddev_suspend calls synchronize_rcu(), mddev_congested can
avoid races by included the whole call inside an rcu_read_lock()
region.
This require that the congested functions for all subordinate devices
can be run under rcu_lock.  Fortunately this is the case.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-04 08:35:52 +11:00
NeilBrown
85572d7c75 md: rename mddev->write_lock to mddev->lock
This lock is used for (slightly) more than helping with writing
superblocks, and it will soon be extended further.  So the
name is inappropriate.

Also, the _irq variant hasn't been needed since 2.6.37 as it is
never taking from interrupt or bh context.

So:
  -rename write_lock to lock
  -document what it protects
  -remove _irq ... except in md_flush_request() as there
     is no wait_event_lock() (with no _irq).  This can be
     cleaned up after appropriate changes to wait.h.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-04 08:35:52 +11:00
NeilBrown
ea664c8245 md/raid5: need_this_block: tidy/fix last condition.
That last condition is unclear and over cautious.

There are two related issues here.

If a partial write is destined for a missing device, then
either RMW or RCW can work.  We must read all the available
block.  Only then can the missing blocks be calculated, and
then the parity update performed.

If RMW is not an option, then there is a complication even
without partial writes.  If we would need to read a missing
device to perform the reconstruction, then we must first read every
block so the missing device data can be computed.
This is the case for RAID6 (Which currently does not support
RMW) and for times when we don't trust the parity (after a crash)
and so are in the process of resyncing it.

So make these two cases more clear and separate, and perform
the relevant tests more  thoroughly.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-04 08:35:51 +11:00
NeilBrown
a9d56950f7 md/raid5: need_this_block: start simplifying the last two conditions.
Both the last two cases are only relevant if something has failed and
something needs to be written (but not over-written), and if it is OK
to pre-read blocks at this point.  So factor out those tests and
explain them.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-04 08:35:51 +11:00
NeilBrown
a79cfe12c6 md/raid5: separate out the easy conditions in need_this_block.
Some of the conditions in need_this_block have very straight
forward motivation.  Separate those out and document them.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-04 08:35:51 +11:00
NeilBrown
2c58f06e6f md/raid5: separate large if clause out of fetch_block().
fetch_block() has a very large and hard to read 'if' condition.

Separate it into its own function so that it can be
made more readable.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-04 08:35:51 +11:00
Jes Sorensen
ad3ab8b608 md: do_release_stripe(): No need to call md_wakeup_thread() twice
67f455486d introduced a call to
md_wakeup_thread() when adding to the delayed_list. However the md
thread is woken up unconditionally just below.

Remove the unnecessary wakeup call.

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-04 08:35:51 +11:00
NeilBrown
d959014334 md/bitmap: fix a might_sleep() warning.
commit 8eb23b9f35
    sched: Debug nested sleeps

causes false-positive warnings in RAID5 code.

This annotation removes them and adds a comment
explaining why there is no real problem.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-02 17:08:03 +11:00
NeilBrown
b1b02fe97f md/raid5: fix another livelock caused by non-aligned writes.
If a non-page-aligned write is destined for a device which
is missing/faulty, we can deadlock.

As the target device is missing, a read-modify-write cycle
is not possible.
As the write is not for a full-page, a recontruct-write cycle
is not possible.

This should be handled by logic in fetch_block() which notices
there is a non-R5_OVERWRITE write to a missing device, and so
loads all blocks.

However since commit 67f455486d, that code requires
STRIPE_PREREAD_ACTIVE before it will active, and those circumstances
never set STRIPE_PREREAD_ACTIVE.

So: in handle_stripe_dirtying, if neither rmw or rcw was possible,
set STRIPE_DELAYED, which will cause STRIPE_PREREAD_ACTIVE be set
after a suitable delay.

Fixes: 67f455486d
Cc: stable@vger.kernel.org (v3.16+)
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Tested-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-02 16:57:17 +11:00
Keith Busch
febf71588c block: require blk_rq_prep_clone() be given an initialized clone request
Prepare to allow blk_rq_prep_clone() to accept clone requests that were
allocated from blk-mq request queues.  As such the blk_rq_prep_clone()
caller must first initialize the clone request.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-01-28 09:44:11 -07:00
Joe Thornber
2a7eaea02b dm thin: don't allow messages to be sent to a pool target in READ_ONLY or FAIL mode
You can't modify the metadata in these modes.  It's better to fail these
messages immediately than let the block-manager deny write locks on
metadata blocks.  Otherwise these failed metadata changes will trigger
'needs_check' to get set in the metadata superblock -- requiring repair
using the thin_check utility.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-01-28 10:00:34 -05:00
Joe Thornber
766a78882d dm cache: fix missing ERR_PTR returns and handling
Commit 9b1cc9f251 ("dm cache: share cache-metadata object across
inactive and active DM tables") mistakenly ignored the use of ERR_PTR
returns.  Restore missing IS_ERR checks and ERR_PTR returns where
appropriate.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-01-28 09:59:20 -05:00
Mikulas Patocka
96b26c8c64 dm: fix handling of multiple internal suspends
Commit ffcc393641 ("dm: enhance internal suspend and resume interface")
attempted to handle multiple internal suspends on the same device, but
it did that incorrectly.  When these functions are called in this order
on the same device the device is no longer suspended, but it should be:
	dm_internal_suspend_noflush
	dm_internal_suspend_noflush
	dm_internal_resume

Fix this bug by maintaining an 'internal_suspend_count' and resuming
the device when this count drops to zero.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-01-24 14:50:08 -05:00
Joe Thornber
a59db67656 dm cache: fix problematic dual use of a single migration count variable
Introduce a new variable to count the number of allocated migration
structures.  The existing variable cache->nr_migrations became
overloaded.  It was used to:

 i) track of the number of migrations in flight for the purposes of
    quiescing during suspend.

 ii) to estimate the amount of background IO occuring.

Recent discard changes meant that REQ_DISCARD bios are processed with
a migration.  Discards are not background IO so nr_migrations was not
incremented.  However this could cause quiescing to complete early.

(i) is now handled with a new variable cache->nr_allocated_migrations.
cache->nr_migrations has been renamed cache->nr_io_migrations.
cleanup_migration() is now called free_io_migration(), since it
decrements that variable.

Also, remove the unused cache->next_migration variable that got replaced
with with prealloc_structs a while ago.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-01-23 11:06:08 -05:00
Joe Thornber
9b1cc9f251 dm cache: share cache-metadata object across inactive and active DM tables
If a DM table is reloaded with an inactive table when the device is not
suspended (normal procedure for LVM2), then there will be two dm-bufio
objects that can diverge.  This can lead to a situation where the
inactive table uses bufio to read metadata at the same time the active
table writes metadata -- resulting in the inactive table having stale
metadata buffers once it is promoted to the active table slot.

Fix this by using reference counting and a global list of cache metadata
objects to ensure there is only one metadata object per metadata device.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-01-23 10:57:15 -05:00
Ingo Molnar
f49028292c Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull RCU updates from Paul E. McKenney:

  - Documentation updates.

  - Miscellaneous fixes.

  - Preemptible-RCU fixes, including fixing an old bug in the
    interaction of RCU priority boosting and CPU hotplug.

  - SRCU updates.

  - RCU CPU stall-warning updates.

  - RCU torture-test updates.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-01-21 06:12:21 +01:00
Christoph Jaeger
6341e62b21 kconfig: use bool instead of boolean for type definition attributes
Support for keyword 'boolean' will be dropped later on.

No functional change.

Reference: http://lkml.kernel.org/r/cover.1418003065.git.cj@linux.com
Signed-off-by: Christoph Jaeger <cj@linux.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2015-01-07 13:08:04 +01:00
Pranith Kumar
83fe27ea53 rcu: Make SRCU optional by using CONFIG_SRCU
SRCU is not necessary to be compiled by default in all cases. For tinification
efforts not compiling SRCU unless necessary is desirable.

The current patch tries to make compiling SRCU optional by introducing a new
Kconfig option CONFIG_SRCU which is selected when any of the components making
use of SRCU are selected.

If we do not select CONFIG_SRCU, srcu.o will not be compiled at all.

   text    data     bss     dec     hex filename
   2007       0       0    2007     7d7 kernel/rcu/srcu.o

Size of arch/powerpc/boot/zImage changes from

   text    data     bss     dec     hex filename
 831552   64180   23944  919676   e087c arch/powerpc/boot/zImage : before
 829504   64180   23952  917636   e0084 arch/powerpc/boot/zImage : after

so the savings are about ~2000 bytes.

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: resolve conflict due to removal of arch/ia64/kvm/Kconfig. ]
2015-01-06 11:04:29 -08:00
zhendong chen
5164bece16 dm: fix missed error code if .end_io isn't implemented by target_type
In bio-based DM's clone_endio(), when target_type doesn't implement
.end_io (e.g. linear) r will be always be initialized 0.  So if a
WRITE SAME bio fails WRITE SAME will not be disabled as intended.

Fix this by initializing r to error, rather than 0, in clone_endio().

Signed-off-by: Alex Chen <alex.chen@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Fixes: 7eee4ae2db ("dm: disable WRITE SAME if it fails")
Cc: stable@vger.kernel.org
2014-12-17 12:31:13 -05:00
Marc Dionne
2b94e8960c dm thin: fix crash by initializing thin device's refcount and completion earlier
Commit 80e96c5484 ("dm thin: do not allow thin device activation
while pool is suspended") delayed the initialization of a new thin
device's refcount and completion until after this new thin was added
to the pool's active_thins list and the pool lock is released.  This
opens a race with a worker thread that walks the list and calls
thin_get/put, noticing that the refcount goes to 0 and calling
complete, freezing up the system and giving the oops below:

 kernel: BUG: unable to handle kernel NULL pointer dereference at           (null)
 kernel: IP: [<ffffffff810d360b>] __wake_up_common+0x2b/0x90

 kernel: Call Trace:
 kernel: [<ffffffff810d3683>] __wake_up_locked+0x13/0x20
 kernel: [<ffffffff810d3dc7>] complete+0x37/0x50
 kernel: [<ffffffffa0595c50>] thin_put+0x20/0x30 [dm_thin_pool]
 kernel: [<ffffffffa059aab7>] do_worker+0x667/0x870 [dm_thin_pool]
 kernel: [<ffffffff816a8a4c>] ? __schedule+0x3ac/0x9a0
 kernel: [<ffffffff810b1aef>] process_one_work+0x14f/0x400
 kernel: [<ffffffff810b206b>] worker_thread+0x6b/0x490
 kernel: [<ffffffff810b2000>] ? rescuer_thread+0x260/0x260
 kernel: [<ffffffff810b6a7b>] kthread+0xdb/0x100
 kernel: [<ffffffff810b69a0>] ? kthread_create_on_node+0x170/0x170
 kernel: [<ffffffff816ad7ec>] ret_from_fork+0x7c/0xb0
 kernel: [<ffffffff810b69a0>] ? kthread_create_on_node+0x170/0x170

Set the thin device's initial refcount and initialize the completion
before adding it to the pool's active_thins list in thin_ctr().

Signed-off-by: Marc Dionne <marc.dionne@your-file-system.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-12-17 12:06:25 -05:00
Joe Thornber
2c43fd26e4 dm thin: fix missing out-of-data-space to write mode transition if blocks are released
Discard bios and thin device deletion have the potential to release data
blocks.  If the thin-pool is in out-of-data-space mode, and blocks were
released, transition the thin-pool back to full write mode.

The correct time to do this is just after the thin-pool metadata commit.
It cannot be done before the commit because the space maps will not
allow immediate reuse of the data blocks in case there's a rollback
following power failure.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-12-17 11:59:36 -05:00
Joe Thornber
45ec9bd0fd dm thin: fix inability to discard blocks when in out-of-data-space mode
When the pool was in PM_OUT_OF_SPACE mode its process_prepared_discard
function pointer was incorrectly being set to
process_prepared_discard_passdown rather than process_prepared_discard.

This incorrect function pointer meant the discard was being passed down,
but not effecting the mapping.  As such any discard that was issued, in
an attempt to reclaim blocks, would not successfully free data space.

Reported-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-12-17 11:59:36 -05:00
Linus Torvalds
8fd9589ced Three fixes for md
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Merge tag 'md/3.19' of git://neil.brown.name/md

Pull md updates from Neil Brown:
 "Three fixes for md.

   I did have a largish set of locking changes queued, but late testing
  showed they weren't quite as stable as I thought and while I fixed
  what I found, I decided it safer to delay them a release ...
  particularly as I'll be AFK for a few weeks.  So expect a larger batch
  next time :-)"

* tag 'md/3.19' of git://neil.brown.name/md:
  md: Check MD_RECOVERY_RUNNING as well as ->sync_thread.
  md: fix semicolon.cocci warnings
  md/raid5: fetch_block must fetch all the blocks handle_stripe_dirtying wants.
2014-12-14 12:13:05 -08:00
Linus Torvalds
9ea18f8cab Merge branch 'for-3.19/drivers' of git://git.kernel.dk/linux-block
Pull block layer driver updates from Jens Axboe:

 - NVMe updates:
        - The blk-mq conversion from Matias (and others)

        - A stack of NVMe bug fixes from the nvme tree, mostly from Keith.

        - Various bug fixes from me, fixing issues in both the blk-mq
          conversion and generic bugs.

        - Abort and CPU online fix from Sam.

        - Hot add/remove fix from Indraneel.

 - A couple of drbd fixes from the drbd team (Andreas, Lars, Philipp)

 - With the generic IO stat accounting from 3.19/core, converting md,
   bcache, and rsxx to use those.  From Gu Zheng.

 - Boundary check for queue/irq mode for null_blk from Matias.  Fixes
   cases where invalid values could be given, causing the device to hang.

 - The xen blkfront pull request, with two bug fixes from Vitaly.

* 'for-3.19/drivers' of git://git.kernel.dk/linux-block: (56 commits)
  NVMe: fix race condition in nvme_submit_sync_cmd()
  NVMe: fix retry/error logic in nvme_queue_rq()
  NVMe: Fix FS mount issue (hot-remove followed by hot-add)
  NVMe: fix error return checking from blk_mq_alloc_request()
  NVMe: fix freeing of wrong request in abort path
  xen/blkfront: remove redundant flush_op
  xen/blkfront: improve protection against issuing unsupported REQ_FUA
  NVMe: Fix command setup on IO retry
  null_blk: boundary check queue_mode and irqmode
  block/rsxx: use generic io stats accounting functions to simplify io stat accounting
  md: use generic io stats accounting functions to simplify io stat accounting
  drbd: use generic io stats accounting functions to simplify io stat accounting
  md/bcache: use generic io stats accounting functions to simplify io stat accounting
  NVMe: Update module version major number
  NVMe: fail pci initialization if the device doesn't have any BARs
  NVMe: add ->exit_hctx() hook
  NVMe: make setup work for devices that don't do INTx
  NVMe: enable IO stats by default
  NVMe: nvme_submit_async_admin_req() must use atomic rq allocation
  NVMe: replace blk_put_request() with blk_mq_free_request()
  ...
2014-12-13 14:22:26 -08:00
NeilBrown
f851b60db0 md: Check MD_RECOVERY_RUNNING as well as ->sync_thread.
A recent change to md started the ->sync_thread from a asynchronously
from a work_queue rather than synchronously.  This means that there
can be a small window between the time when MD_RECOVERY_RUNNING is set
and when ->sync_thread is set.

So code that checks ->sync_thread might now conclude that the thread
has not been started and (because a lock is held) will not be started.
That is no longer the case.

Most of those places are best fixed by testing MD_RECOVERY_RUNNING
as well.  To make this completely reliable, we wake_up(&resync_wait)
after clearing that flag as well as after clearing ->sync_thread.

Other places are better served by flushing the relevant workqueue
to ensure that that if the sync thread was starting, it has now
started.  This is particularly best if we are about to stop the
sync thread.

Fixes: ac05f25669
Signed-off-by: NeilBrown <neilb@suse.de>
2014-12-11 10:02:10 +11:00
Linus Torvalds
140dfc9299 - Significant DM thin-provisioning performance improvements to meet
performance requirements that were requested by the Gluster
   distributed filesystem.  Specifically, dm-thinp now takes care to
   aggregate IO that will be issued to the same thinp block before
   issuing IO to the underlying devices.  This really helps improve
   performance on HW RAID6 devices that have a writeback cache because it
   avoids RMW in the HW RAID controller.
 
 - Some stable fixes: fix leak in DM bufio if integrity profiles were
   enabled, use memzero_explicit in DM crypt to avoid any potential for
   information leak, and a DM cache fix to properly mark a cache block
   dirty if it was promoted to the cache via the overwrite optimization.
 
 - A few simple DM persistent data library fixes
 
 - DM cache multiqueue policy block promotion improvements.
 
 - DM cache discard improvements that take advantage of range
   (multiblock) discard support in the DM bio-prison.  This allows for
   much more efficient bulk discard processing (e.g. when mkfs.xfs
   discards the entire device).
 
 - Some small optimizations in DM core and RCU deference cleanups
 
 - DM core changes to suspend/resume code to introduce the new internal
   suspend/resume interface that the DM thin-pool target now uses to
   suspend/resume active thin devices when the thin-pool must
   suspend/resume.  This avoids forcing userspace to track all active
   thin volumes in a thin-pool when the thin-pool is suspended for the
   purposes of metadata or data space resize.
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Merge tag 'dm-3.19-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - Significant DM thin-provisioning performance improvements to meet
   performance requirements that were requested by the Gluster
   distributed filesystem.

   Specifically, dm-thinp now takes care to aggregate IO that will be
   issued to the same thinp block before issuing IO to the underlying
   devices.  This really helps improve performance on HW RAID6 devices
   that have a writeback cache because it avoids RMW in the HW RAID
   controller.

 - Some stable fixes: fix leak in DM bufio if integrity profiles were
   enabled, use memzero_explicit in DM crypt to avoid any potential for
   information leak, and a DM cache fix to properly mark a cache block
   dirty if it was promoted to the cache via the overwrite optimization.

 - A few simple DM persistent data library fixes

 - DM cache multiqueue policy block promotion improvements.

 - DM cache discard improvements that take advantage of range
   (multiblock) discard support in the DM bio-prison.  This allows for
   much more efficient bulk discard processing (e.g.  when mkfs.xfs
   discards the entire device).

 - Some small optimizations in DM core and RCU deference cleanups

 - DM core changes to suspend/resume code to introduce the new internal
   suspend/resume interface that the DM thin-pool target now uses to
   suspend/resume active thin devices when the thin-pool must
   suspend/resume.

   This avoids forcing userspace to track all active thin volumes in a
   thin-pool when the thin-pool is suspended for the purposes of
   metadata or data space resize.

* tag 'dm-3.19-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (49 commits)
  dm crypt: use memzero_explicit for on-stack buffer
  dm space map metadata: fix sm_bootstrap_get_count()
  dm space map metadata: fix sm_bootstrap_get_nr_blocks()
  dm bufio: fix memleak when using a dm_buffer's inline bio
  dm cache: fix spurious cell_defer when dealing with partial block at end of device
  dm cache: dirty flag was mistakenly being cleared when promoting via overwrite
  dm cache: only use overwrite optimisation for promotion when in writeback mode
  dm cache: discard block size must be a multiple of cache block size
  dm cache: fix a harmless race when working out if a block is discarded
  dm cache: when reloading a discard bitset allow for a different discard block size
  dm cache: fix some issues with the new discard range support
  dm array: if resizing the array is a noop set the new root to the old one
  dm: use rcu_dereference_protected instead of rcu_dereference
  dm thin: fix pool_io_hints to avoid looking at max_hw_sectors
  dm thin: suspend/resume active thin devices when reloading thin-pool
  dm: enhance internal suspend and resume interface
  dm thin: do not allow thin device activation while pool is suspended
  dm: add presuspend_undo hook to target_type
  dm: return earlier from dm_blk_ioctl if target doesn't implement .ioctl
  dm thin: remove stale 'trim' message in block comment above pool_message
  ...
2014-12-08 21:10:03 -08:00
kbuild test robot
7d7e64f2ec md: fix semicolon.cocci warnings
drivers/md/md.c:7175:43-44: Unneeded semicolon

 Removes unneeded semicolon.

Generated by: scripts/coccinelle/misc/semicolon.cocci

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2014-12-03 16:07:59 +11:00
NeilBrown
108cef3aa4 md/raid5: fetch_block must fetch all the blocks handle_stripe_dirtying wants.
It is critical that fetch_block() and handle_stripe_dirtying()
are consistent in their analysis of what needs to be loaded.
Otherwise raid5 can wait forever for a block that won't be loaded.

Currently when writing to a RAID5 that is resyncing, to a location
beyond the resync offset, handle_stripe_dirtying chooses a
reconstruct-write cycle, but fetch_block() assumes a
read-modify-write, and a lockup can happen.

So treat that case just like RAID6, just as we do in
handle_stripe_dirtying.  RAID6 always does reconstruct-write.

This bug was introduced when the behaviour of handle_stripe_dirtying
was changed in 3.7, so the patch is suitable for any kernel since,
though it will need careful merging for some versions.

Cc: stable@vger.kernel.org (v3.7+)
Fixes: a7854487cd
Reported-by: Henry Cai <henryplusplus@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2014-12-03 16:07:58 +11:00
Milan Broz
1a71d6ffe1 dm crypt: use memzero_explicit for on-stack buffer
Use memzero_explicit to cleanup sensitive data allocated on stack
to prevent the compiler from optimizing and removing memset() calls.

Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-12-02 10:25:07 -05:00
Joe Thornber
02717d9855 dm space map metadata: fix sm_bootstrap_get_count()
Must set 'result' accordingly rather than return it.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-12-02 10:25:06 -05:00
Dan Carpenter
c1c6156fe4 dm space map metadata: fix sm_bootstrap_get_nr_blocks()
This function isn't right and it causes a static checker warning:

	drivers/md/dm-thin.c:3016 maybe_resize_data_dev()
	error: potentially using uninitialized 'sb_data_size'.

It should set "*count" and return zero on success the same as the
sm_metadata_get_nr_blocks() function does earlier.

Fixes: 3241b1d3e0 ('dm: add persistent data library')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-12-01 11:31:58 -05:00
Darrick J. Wong
445559cdcb dm bufio: fix memleak when using a dm_buffer's inline bio
When dm-bufio sets out to use the bio built into a struct dm_buffer to
issue an IO, it needs to call bio_reset after it's done with the bio
so that we can free things attached to the bio such as the integrity
payload.  Therefore, inject our own endio callback to take care of
the bio_reset after calling submit_io's end_io callback.

Test case:
1. modprobe scsi_debug delay=0 dif=1 dix=199 ato=1 dev_size_mb=300
2. Set up a dm-bufio client, e.g. dm-verity, on the scsi_debug device
3. Repeatedly read metadata and watch kmalloc-192 leak!

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-12-01 11:31:17 -05:00
Joe Thornber
f824a2af3d dm cache: fix spurious cell_defer when dealing with partial block at end of device
We never bother caching a partial block that is at the back end of the
origin device.  No cell ever gets locked, but the calling code was
assuming it was and trying to release it.

Now the code only releases if the cell has been set to a non NULL
value.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-12-01 11:30:13 -05:00
Joe Thornber
1e32134a5a dm cache: dirty flag was mistakenly being cleared when promoting via overwrite
If the incoming bio is a WRITE and completely covers a block then we
don't bother to do any copying for a promotion operation.  Once this is
done the cache block and origin block will be different, so we need to
set it to 'dirty'.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-12-01 11:30:12 -05:00
Joe Thornber
f29a3147e2 dm cache: only use overwrite optimisation for promotion when in writeback mode
Overwrite causes the cache block and origin blocks to diverge, which
is only allowed in writeback mode.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-12-01 11:30:12 -05:00
Joe Thornber
2bb812df63 dm cache: discard block size must be a multiple of cache block size
Otherwise the cache blocks may span two discard blocks, which we don't
handle when doing the discard lookup.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-12-01 11:30:11 -05:00
Joe Thornber
43c32bf2b0 dm cache: fix a harmless race when working out if a block is discarded
It is more correct to hold the cell before checking the discard state.
These flags are only used as hints to the policy so this change will
have negligable effect.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-12-01 11:30:11 -05:00
Joe Thornber
3e2e1c3098 dm cache: when reloading a discard bitset allow for a different discard block size
The discard block size can change if the origin changes size or if an
old DM cache is upgraded from using a discard block size that was equal
to cache block size.

To fix this an extent of discarded blocks is established for the purpose
of translating the old discard block size to the new in-core discard
block size and set bits.  The old (potentially huge) discard bitset is
left ondisk until it is re-written using the new in-core information on
the next successful DM cache shutdown.

Fixes: 7ae34e7778 ("dm cache: improve discard support")
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-12-01 11:30:10 -05:00
Joe Thornber
2572629a13 dm cache: fix some issues with the new discard range support
Commit 7ae34e777 ("dm cache: improve discard support") needed to also:
- discontinue having DM core split the discard bios on cache block
  boundaries
- calculate the cache's discard_nr_blocks relative to the determined
  discard_block_size rather than using oblock_to_dblock()

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-12-01 11:30:09 -05:00
Joe Thornber
8001e87d0e dm array: if resizing the array is a noop set the new root to the old one
This could've been quite bad (to return success but not update the new
root to point at the old) but in practice the only known consumer of the
dm array code is the DM cache target.  And the DM cache target passes in
the same old root to array_resize() anyway.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-12-01 11:30:07 -05:00
Gu Zheng
18c0b223cf md: use generic io stats accounting functions to simplify io stat accounting
Use generic io stats accounting help functions (generic_{start,end}_io_acct)
to simplify io stat accounting.

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-11-24 08:05:16 -07:00
Gu Zheng
aae4933da9 md/bcache: use generic io stats accounting functions to simplify io stat accounting
Use generic io stats accounting help functions (generic_{start,end}_io_acct)
to simplify io stat accounting.

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Acked-by: Kent Overstreet <kmo@datera.io>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-11-24 08:05:12 -07:00
Eric Dumazet
a12f5d48bd dm: use rcu_dereference_protected instead of rcu_dereference
rcu_dereference() should be used in sections protected by rcu_read_lock.

For writers, holding some kind of mutex or lock,
rcu_dereference_protected() is the way to go, adding explicit lockdep
bits.

In __unbind(), we are the last user of this mapped device, so can use
the constant '1' instead of a lockdep_is_held(), not consistent with
other uses of rcu_dereference_protected() which use md->suspend_lock
mutex.

Reported-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: 33423974bf ("dm: Use rcu_dereference() for accessing rcu pointer")
Cc: Pranith Kumar <bobby.prani@gmail.com>
[snitzer: allow lines longer than 80 columns, refine subject]
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-23 20:32:45 -05:00
Mike Snitzer
d200c30ef0 dm thin: fix pool_io_hints to avoid looking at max_hw_sectors
Simplify the pool_io_hints code that works to establish a max_sectors
value that is a power-of-2 factor of the thin-pool's blocksize.  The
biggest associated improvement is that the DM thin-pool is no longer
concerning itself with the data device's max_hw_sectors when adjusting
max_sectors.

This fixes the relative fragility of the original "dm thin: adjust
max_sectors_kb based on thinp blocksize" commit that only became
apparent when testing was performed using a DM thin-pool ontop of a
virtio_blk device.  One proposed upstream patch detailed the problems
inherent in virtio_blk: https://lkml.org/lkml/2014/11/20/611

So even though virtio_blk incorrectly set its max_hw_sectors it actually
helped make it clear that we need DM thinp to be tolerant of any future
Linux driver that incorrectly sets max_hw_sectors.

We only need to be concerned with modifying the thin-pool device's
max_sectors limit if it is smaller than the thin-pool's blocksize.  In
this case the value of max_sectors does become a limiting factor when
upper layers (e.g. filesystems) construct their bios.  But if the
hardware can support IOs larger than the thin-pool's blocksize the user
is encouraged to adjust the thin-pool's data device's max_sectors
accordingly -- doing so will enable the thin-pool to inherit the
established user-defined max_sectors.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-21 12:54:23 -05:00
Mike Snitzer
583024d248 dm thin: suspend/resume active thin devices when reloading thin-pool
Before this change it was expected that userspace would first suspend
all active thin devices, reload/resize the thin-pool target, then resume
all active thin devices.  Now the thin-pool suspend/resume will trigger
the suspend/resume of all active thins via appropriate calls to
dm_internal_suspend and dm_internal_resume.

Store the mapped_device for each thin device in struct thin_c to make
these calls possible.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
2014-11-19 12:34:08 -05:00
Mike Snitzer
ffcc393641 dm: enhance internal suspend and resume interface
Rename dm_internal_{suspend,resume} to dm_internal_{suspend,resume}_fast
-- dm-stats will continue using these methods to avoid all the extra
suspend/resume logic that is not needed in order to quickly flush IO.

Introduce dm_internal_suspend_noflush() variant that actually calls the
mapped_device's target callbacks -- otherwise target-specific hooks are
avoided (e.g. dm-thin's thin_presuspend and thin_postsuspend).  Common
code between dm_internal_{suspend_noflush,resume} and
dm_{suspend,resume} was factored out as __dm_{suspend,resume}.

Update dm_internal_{suspend_noflush,resume} to always take and release
the mapped_device's suspend_lock.  Also update dm_{suspend,resume} to be
aware of potential for DM_INTERNAL_SUSPEND_FLAG to be set and respond
accordingly by interruptibly waiting for the DM_INTERNAL_SUSPEND_FLAG to
be cleared.  Add lockdep annotation to dm_suspend() and dm_resume().

The existing DM_SUSPEND_FLAG remains unchanged.
DM_INTERNAL_SUSPEND_FLAG is set by dm_internal_suspend_noflush() and
cleared by dm_internal_resume().

Both DM_SUSPEND_FLAG and DM_INTERNAL_SUSPEND_FLAG may be set if a device
was already suspended when dm_internal_suspend_noflush() was called --
this can be thought of as a "nested suspend".  A "nested suspend" can
occur with legacy userspace dm-thin code that might suspend all active
thin volumes before suspending the pool for resize.

But otherwise, in the normal dm-thin-pool suspend case moving forward:
the thin-pool will have DM_SUSPEND_FLAG set and all active thins from
that thin-pool will have DM_INTERNAL_SUSPEND_FLAG set.

Also add DM_INTERNAL_SUSPEND_FLAG to status report.  This new
DM_INTERNAL_SUSPEND_FLAG state is being reported to assist with
debugging (e.g. 'dmsetup info' will report an internally suspended
device accordingly).

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
2014-11-19 12:31:17 -05:00
Mike Snitzer
80e96c5484 dm thin: do not allow thin device activation while pool is suspended
Otherwise IO could be issued to the pool while it is suspended.

Care was taken to properly interlock between the thin and thin-pool
targets when accessing the pool's 'suspended' flag.  The thin_ctr will
not add a new thin device to the pool's active_thins list if the pool is
susepended.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
2014-11-19 11:25:36 -05:00
Mike Snitzer
d67ee213fa dm: add presuspend_undo hook to target_type
The DM thin-pool target now must undo the changes performed during
pool_presuspend() so introduce presuspend_undo hook in target_type.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
2014-11-19 11:24:59 -05:00
Mike Snitzer
4d341d8216 dm: return earlier from dm_blk_ioctl if target doesn't implement .ioctl
No point checking if the device is suspended if the current target
doesn't even implement .ioctl

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-19 11:24:56 -05:00
Linus Torvalds
0fbae13642 One fix for md for 3.18.
This fixes a regression introduced in 3.13.
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Merge tag 'md/3.18-fix' of git://neil.brown.name/md

Pull md bugfix from Neil Brown:
 "One fix for md for 3.18.

  This fixes a regression introduced in 3.13"

* tag 'md/3.18-fix' of git://neil.brown.name/md:
  md: Always set RECOVERY_NEEDED when clearing RECOVERY_FROZEN
2014-11-16 15:34:31 -08:00
NeilBrown
45eaf45dfa md: Always set RECOVERY_NEEDED when clearing RECOVERY_FROZEN
md_check_recovery will skip any recovery and also clear
MD_RECOVERY_NEEDED if MD_RECOVERY_FROZEN is set.
So when we clear _FROZEN, we must set _NEEDED and ensure that
md_check_recovery gets run.
Otherwise we could miss out on something that is needed.

In particular, this can make it impossible to remove a
failed device from an array is the  'recovery-needed' processing
didn't happen.
Suitable for stable kernels since 3.13.

Cc: stable@vger.kernel.org (3.13+)
Reported-and-tested-by: Joe Lawrence <joe.lawrence@stratus.com>
Fixes: 30b8feb730
Signed-off-by: NeilBrown <neilb@suse.de>
2014-11-17 09:17:46 +11:00
Linus Torvalds
5a7a662cc6 . stable fix for dm-thin that avoids normal IO racing with discard
. stable fix for a dm-cache related bug in dm-btree walking code that
   results from using very large fast device (e.g. 4T) with a very small
   cache blocksize (e.g. 32K) -- this is a very uncommon configuration
 
 . a couple fixes for dm-raid (one for stable and the other addresses a
   crash in 3.18-rc1 code)
 
 . stable fix for dm-thinp that addresses a very rare dm-bufio bug having
   to do with memory reclaimation (via shrinker) when using dm-thinp
   ontop of loopback devices
 
 . fix a leak in dm-stripe target constructor's error path
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Merge tag 'dm-3.18-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:

 - stable fix for dm-thin that avoids normal IO racing with discard

 - stable fix for a dm-cache related bug in dm-btree walking code that
   results from using very large fast device (eg 4T) with a very small
   cache blocksize (eg 32K) -- this is a very uncommon configuration

 - a couple fixes for dm-raid (one for stable and the other addresses a
   crash in 3.18-rc1 code)

 - stable fix for dm-thinp that addresses a very rare dm-bufio bug
   having to do with memory reclaimation (via shrinker) when using
   dm-thinp ontop of loopback devices

 - fix a leak in dm-stripe target constructor's error path

* tag 'dm-3.18-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm btree: fix a recursion depth bug in btree walking code
  dm thin: grab a virtual cell before looking up the mapping
  dm raid: fix inaccessible superblocks causing oops in configure_discard_support
  dm raid: ensure superblock's size matches device's logical block size
  dm bufio: change __GFP_IO to __GFP_FS in shrinker callbacks
  dm stripe: fix potential for leak in stripe_ctr error path
2014-11-13 09:19:20 -08:00
Mike Snitzer
5ec02084f6 dm thin: remove stale 'trim' message in block comment above pool_message
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-12 20:15:05 -05:00
Mikulas Patocka
17181fb7a0 dm thin: fix a race in thin_dtr
As long as struct thin_c is in the list, anyone can grab a reference of
it.  Consequently, we must wait for the reference count to drop to zero
*after* we remove the structure from the list, not before.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-12 20:15:04 -05:00
Joe Thornber
d1d9220cba dm cache: emit a warning message if there are a lot of cache blocks
Loading and saving millions of block mappings takes time.  We may as
well explain what's going on, and encourage people to use a larger
cache block size.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-12 20:14:59 -05:00
Joe Thornber
7ae34e7778 dm cache: improve discard support
Safely allow the discard blocksize to be larger than the cache blocksize
by using the bio prison's range locking support.  This also improves
discard performance considerly because larger discards are issued to the
dm-cache device.  The discard blocksize was always intended to be
greater than the cache blocksize.  But until now it wasn't implemented
safely.

Also, by safely restoring the ability to have discard blocksize larger
than cache blocksize we're able to significantly reduce the memory used
for the cache's discard bitset.  Before, with a small discard blocksize,
the discard bitset could get quite large because its size is a function
of the discard blocksize and the origin device's size.  For example,
previously, using a 32KB cache blocksize with a 40TB origin resulted in
1280MB of incore memory use for the discard bitset!  Now, the discard
blocksize is scaled up accordingly to ensure the discard bitset is
capped at 2**14 bits, or 16KB.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:30 -05:00
Joe Thornber
08b184514f dm cache: revert "prevent corruption caused by discard_block_size > cache_block_size"
This reverts commit d132cc6d9e because we
actually do want to allow the discard blocksize to be larger than the
cache blocksize.  Further dm-cache discard changes will make this
possible.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:30 -05:00
Joe Thornber
1bad9bc4ee dm cache: revert "remove remainder of distinct discard block size"
This reverts commit 64ab346a36 because we
actually do want to allow the discard blocksize to be larger than the
cache blocksize.  Further dm-cache discard changes will make this
possible.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:30 -05:00
Joe Thornber
5f274d8865 dm bio prison: introduce support for locking ranges of blocks
Ranges will be placed in the same cell if they overlap.

Range locking is a prerequisite for more efficient multi-block discard
support in both the cache and thin-provisioning targets.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:30 -05:00
Mike Snitzer
f1afb36a61 dm cache policy mq: simplify ability to promote sequential IO to the cache
Before, if the user wanted sequential IO to be promoted to the cache
they'd have to set sequential_threshold to some nebulous large value.

Now, the user may easily disable sequential IO detection (and sequential
IO's implicit bypass of the cache) by setting sequential_threshold to 0.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:30 -05:00
Joe Thornber
b155aa0e5a dm cache policy mq: tweak algorithm that decides when to promote a block
Rather than maintaining a separate promote_threshold variable that we
periodically update we now use the hit count of the oldest clean
block.  Also add a fudge factor to discourage demoting dirty blocks.

With some tests this has a sizeable difference, because the old code
was too eager to demote blocks.  For example, device-mapper-test-suite's
git_extract_cache_quick test goes from taking 190 seconds, to 142
(linear on spindle takes 250).

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:29 -05:00
Hannes Reinecke
41abc4e1af dm: do not call dm_sync_table() when creating new devices
When creating new devices dm_sync_table() calls
synchronize_rcu_expedited(), causing _all_ pending RCU pointers to be
flushed. This causes a latency overhead that is especially noticeable
when creating lots of devices.

And all of this is pointless as there are no old maps to be
disconnected, and hence no stale pointers which would need to be
cleared up.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:29 -05:00
Pranith Kumar
6fa9952097 dm: sparse: Annotate field with __rcu for checking
Annotate the map field with __rcu since this is a rcu pointer which is checked
by sparse.

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:29 -05:00
Pranith Kumar
33423974bf dm: Use rcu_dereference() for accessing rcu pointer
The map field in 'struct mapped_device' is an rcu pointer. Use rcu_dereference()
while accessing it.

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:29 -05:00
Mike Snitzer
42d6a8ce3c dm thin: refactor requeue_io to eliminate spinlock bouncing
Also refactor some other bio_list erroring helpers.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:29 -05:00
Mike Snitzer
9d094eebd7 dm thin: optimize retry_bios_on_resume
Eliminate redundant should_error_unserviceable_bio check and error
loop.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:28 -05:00
Joe Thornber
ac4c3f34a9 dm thin: sort the deferred cells
Sort the cells in logical block order before processing each cell in
process_thin_deferred_cells().  This significantly improves the ondisk
layout on rotational storage, whereby improving read performance.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:28 -05:00
Joe Thornber
23ca2bb6c6 dm thin: direct dispatch when breaking sharing
This use of direct submission in process_shared_bio() reduces latency
for submitting bios in the shared cell by avoiding adding those bios to
the deferred list and waiting for the next iteration of the worker.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:28 -05:00
Joe Thornber
2d759a46b4 dm thin: remap the bios in a cell immediately
This use of direct submission in process_prepared_mapping() reduces
latency for submitting bios in a cell by avoiding adding those bios to
the deferred list and waiting for the next iteration of the worker.

But this direct submission exposes the potential for a race between
releasing a cell and incrementing deferred set.  Fix this by introducing
dm_cell_visit_release() and refactoring inc_remap_and_issue_cell()
accordingly.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:28 -05:00
Joe Thornber
a374bb217b dm thin: defer whole cells rather than individual bios
This avoids dropping the cell, so increases the probability that other
bios will collect within the cell, rather than being passed individually
to the worker.

Also add required process_cell and process_discard_cell error handling
wrappers and set associated pool-mode function pointers accordingly.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:28 -05:00
Mike Snitzer
452d7a620d dm thin: factor out remap_and_issue_overwrite
Purely cleanup of duplicated code, no functional change.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:28 -05:00
Joe Thornber
7a7e97ca58 dm thin: performance improvement to discard processing
When processing a discard bio, if the block is already quiesced do the
discard immediately rather than adding the mapping to a list for the
next iteration of the worker thread.

Discarding a fully provisioned 100G thin volume with 64k block size goes
from 860s to 95s with this change.

Clearly there's something wrong with the worker architecture, more
investigation needed.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:27 -05:00
Mike Snitzer
36f12aeb71 dm thin: implement thin_merge
Introduce thin_merge so that any additional constraints from the data
volume may be taken into account when determing the maximum number of
sectors that can be issued relative to the specified logical offset.

This is particularly important if/when the data volume is layered ontop
of a more sophisticated device (e.g. dm-raid or some other DM target).

Reviewed-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:27 -05:00
Mike Snitzer
148e51baf8 dm: improve documentation and code clarity in dm_merge_bvec
These code changes do not introduce a functional change.

But bio_add_page() will never attempt to build up a bio larger than
queue_max_sectors().  Similarly, bio_get_nr_vecs() is also bound by
queue_max_sectors().  Therefore, there is no point in allowing
dm_merge_bvec() to answer "how many sectors can a bio have at this
offset?" with anything larger than queue_max_sectors().  Using
queue_max_sectors() rather than BIO_MAX_SECTORS serves to more
accurately convey the limits that are being imposed.

Also, use unlikely() to clarify the fact that the defensive code in
dm_merge_bvec() relative to max_size going negative shouldn't ever
happen -- if it does happen there is a bug in the block layer for
requesting larger than dm_merge_bvec()'s initial response for a given
offset.  Also, update a comment in dm_merge_bvec() relative to
max_hw_sectors_kb.  And fix empty newline whitespace.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:27 -05:00
Mike Snitzer
604ea90641 dm thin: adjust max_sectors_kb based on thinp blocksize
Allows for filesystems to submit bios that are a factor of the thinp
blocksize, improving dm-thinp efficiency (particularly when the data
volume is RAID).

Also set io_min to max_sectors_kb if it is a factor of the thinp
blocksize.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:27 -05:00
Joe Thornber
7d327fe051 dm thin: throttle incoming IO
Throttle IO based on the time it's taking the worker to do one loop.
There were reports of hung task timeouts occuring and it was observed
that the excessively long avgqu-sz (as reported by iostat) was
contributing to these hung tasks.

Throttling definitely helps dm-thinp perform better under heavy IO load
(without being detremental by being overzealous).  It reduces avgqu-sz
drastically, e.g.: from 60K to ~6K, and even as low as 150 once metadata
is cached by bufio, when dirty_ratio=5, dirty_background_ratio=2.  And
avgqu-sz stays at or below 30K even with dirty_ratio=20,
dirty_background_ratio=10.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:27 -05:00
Joe Thornber
8a01a6af75 dm thin: prefetch missing metadata pages
Prefetch metadata at the start of the worker thread and then again every
128th bio processed from the deferred list.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:27 -05:00
Joe Thornber
4646015d7e dm transaction manager: add support for prefetching blocks of metadata
Introduce the dm_tm_issue_prefetches interface.  If you're using a
non-blocking clone the tm will build up a list of requested blocks that
weren't in core.  dm_tm_issue_prefetches will request those blocks to be
prefetched.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:26 -05:00
Joe Thornber
e5cfc69a51 dm thin metadata: change dm_thin_find_block to allow blocking, but not issuing, IO
This change is a prerequisite for allowing metadata to be prefetched.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:26 -05:00
Joe Thornber
a195db2d29 dm bio prison: switch to using a red black tree
Previously it was using a fixed sized hash table.  There are times
when very many concurrent cells are held (such as when processing a very
large discard).  When this happens the hash table performance becomes
very poor.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:26 -05:00
Joe Thornber
33096a7822 dm bufio: evict buffers that are past the max age but retain some buffers
These changes help keep metadata backed by dm-bufio in-core longer which
fixes reports of metadata churn in the face of heavy random IO workloads.

Before, bufio evicted all buffers older than DM_BUFIO_DEFAULT_AGE_SECS.
Having a device (e.g. dm-thinp or dm-cache) lose all metadata just
because associated buffers had been idle for some time is unfriendly.

Now, the user may now configure the number of bytes that bufio retains
using the 'retain_bytes' module parameter.  The default is 256K.

Also, the DM_BUFIO_WORK_TIMER_SECS and DM_BUFIO_DEFAULT_AGE_SECS
defaults were quite low so increase them (to 30 and 300 respectively).

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:26 -05:00
Joe Thornber
4e420c452b dm bufio: switch from a huge hash table to an rbtree
Converting over to using an rbtree eliminates a fixed 8MB allocation
from vmalloc space for the hash table.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:26 -05:00
Joe Thornber
9b460d3699 dm btree: fix a recursion depth bug in btree walking code
The walk code was using a 'ro_spine' to hold it's locked btree nodes.
But this data structure is designed for the rolling lock scheme, and
as such automatically unlocks blocks that are two steps up the call
chain.  This is not suitable for the simple recursive walk algorithm,
which retraces its steps.

This code is only used by the persistent array code, which in turn is
only used by dm-cache.  In order to trigger it you need to have a
mapping tree that is more than 2 levels deep; which equates to 8-16
million cache blocks.  For instance a 4T ssd with a very small block
size of 32k only just triggers this bug.

The fix just places the locked blocks on the stack, and stops using
the ro_spine altogether.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-11-10 15:23:58 -05:00
Joe Thornber
c822ed967c dm thin: grab a virtual cell before looking up the mapping
Avoids normal IO racing with discard.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-11-04 13:05:53 -05:00
Heinz Mauelshagen
d20c4b08be dm raid: fix inaccessible superblocks causing oops in configure_discard_support
Commit 48cf06bc5f ("dm raid: add discard support for RAID levels 4, 5
and 6") did not properly handle missing metadata device(s).  A failing
read of the superblock causes the metadata and data devices to be
removed from the dev array in struct raid_set, setting references to
both devices to NULL.  configure_discard_support() nonetheless tries to
access the data dev unconditionally causing an oops.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-10-29 14:53:27 -04:00
Heinz Mauelshagen
40d43c4b4c dm raid: ensure superblock's size matches device's logical block size
The dm-raid superblock (struct dm_raid_superblock) is padded to 512
bytes and that size is being used to read it in from the metadata
device into one preallocated page.

Reading or writing this on a 512-byte sector device works fine but on
a 4096-byte sector device this fails.

Set the dm-raid superblock's size to the logical block size of the
metadata device, because IO at that size is guaranteed too work.  Also
add a size check to avoid silent partial metadata loss in case the
superblock should ever grow past the logical block size or PAGE_SIZE.

[includes pointer math fix from Dan Carpenter]
Reported-by: "Liuhua Wang" <lwang@suse.com>
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-10-21 09:32:15 -04:00
Linus Torvalds
929254d8da . fix DM's long-standing excessive use of memory by leveraging the new
bioset_create_nobvec() interface when creating the DM's bioset
 
 . fix a few bugs in dm-bufio and dm-log-userspace
 
 . add DM core support for a DM multipath use-case that requires loading
   DM tables that contain devices that have failed (by allowing active
   and inactive DM tables to share dm_devs)
 
 . add discard support to the DM raid target; like MD raid456 the user
   must opt-in to raid456 discard support be specifying the
   devices_handle_discard_safely=Y module param.
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Merge tag 'dm-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device-mapper updates from Mike Snitzer:
 "I rebased the DM tree ontop of linux-block.git's 'for-3.18/core' at
  the beginning of October because DM core now depends on the newly
  introduced bioset_create_nobvec() interface.

  Summary:

   - fix DM's long-standing excessive use of memory by leveraging the
     new bioset_create_nobvec() interface when creating the DM's bioset

   - fix a few bugs in dm-bufio and dm-log-userspace

   - add DM core support for a DM multipath use-case that requires
     loading DM tables that contain devices that have failed (by
     allowing active and inactive DM tables to share dm_devs)

   - add discard support to the DM raid target; like MD raid456 the user
     must opt-in to raid456 discard support be specifying the
     devices_handle_discard_safely=Y module param"

* tag 'dm-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm log userspace: fix memory leak in dm_ulog_tfr_init failure path
  dm bufio: when done scanning return from __scan immediately
  dm bufio: update last_accessed when relinking a buffer
  dm raid: add discard support for RAID levels 4, 5 and 6
  dm raid: add discard support for RAID levels 1 and 10
  dm: allow active and inactive tables to share dm_devs
  dm mpath: stop queueing IO when no valid paths exist
  dm: use bioset_create_nobvec()
  dm: remove nr_iovecs parameter from alloc_tio()
2014-10-18 12:25:30 -07:00
Linus Torvalds
e75437fb93 Merge branch 'for-3.18/drivers' of git://git.kernel.dk/linux-block
Pull block layer driver update from Jens Axboe:
 "This is the block driver pull request for 3.18.  Not a lot in there
  this round, and nothing earth shattering.

   - A round of drbd fixes from the linbit team, and an improvement in
     asender performance.

   - Removal of deprecated (and unused) IRQF_DISABLED flag in rsxx and
     hd from Michael Opdenacker.

   - Disable entropy collection from flash devices by default, from Mike
     Snitzer.

   - A small collection of xen blkfront/back fixes from Roger Pau Monné
     and Vitaly Kuznetsov"

* 'for-3.18/drivers' of git://git.kernel.dk/linux-block:
  block: disable entropy contributions for nonrot devices
  xen, blkfront: factor out flush-related checks from do_blkif_request()
  xen-blkback: fix leak on grant map error path
  xen/blkback: unmap all persistent grants when frontend gets disconnected
  rsxx: Remove deprecated IRQF_DISABLED
  block: hd: remove deprecated IRQF_DISABLED
  drbd: use RB_DECLARE_CALLBACKS() to define augment callbacks
  drbd: compute the end before rb_insert_augmented()
  drbd: Add missing newline in resync progress display in /proc/drbd
  drbd: reduce lock contention in drbd_worker
  drbd: Improve asender performance
  drbd: Get rid of the WORK_PENDING macro
  drbd: Get rid of the __no_warn and __cond_lock macros
  drbd: Avoid inconsistent locking warning
  drbd: Remove superfluous newline from "resync_extents" debugfs entry.
  drbd: Use consistent names for all the bi_end_io callbacks
  drbd: Use better variable names
2014-10-18 12:12:45 -07:00
Linus Torvalds
88ed806abb md updates for 3.18
- a few minor bug fixes
 - quite a lot of code tidy-up and simplification
 - remove PRINT_RAID_DEBUG ioctl.  I'm fairly sure
   it is unused, and it isn't particularly useful.
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Merge tag 'md/3.18' of git://neil.brown.name/md

Pull md updates from Neil Brown:
 - a few minor bug fixes
 - quite a lot of code tidy-up and simplification
 - remove PRINT_RAID_DEBUG ioctl.  I'm fairly sure it is unused, and it
   isn't particularly useful.

* tag 'md/3.18' of git://neil.brown.name/md: (21 commits)
  lib/raid6: Add log level to printks
  md: move EXPORT_SYMBOL to after function in md.c
  md: discard PRINT_RAID_DEBUG ioctl
  md: remove MD_BUG()
  md: clean up 'exit' labels in md_ioctl().
  md: remove unnecessary test for MD_MAJOR in md_ioctl()
  md: don't allow "-sync" to be set for device in an active array.
  md: remove unwanted white space from md.c
  md: don't start resync thread directly from md thread.
  md: Just use RCU when checking for overlap between arrays.
  md: avoid potential long delay under pers_lock
  md: simplify export_array()
  md: discard find_rdev_nr in favour of find_rdev_nr_rcu
  md: use wait_event() to simplify md_super_wait()
  md: be more relaxed about stopping an array which isn't started.
  md/raid1: process_checks doesn't use its return value.
  md/raid5: fix init_stripe() inconsistencies
  md/raid10: another memory leak due to reshape.
  md: use set_bit/clear_bit instead of shift/mask for bi_flags changes.
  md/raid1: minor typos and reformatting.
  ...
2014-10-18 11:39:52 -07:00
Mikulas Patocka
9d28eb1244 dm bufio: change __GFP_IO to __GFP_FS in shrinker callbacks
The shrinker uses gfp flags to indicate what kind of operation can the
driver wait for. If __GFP_IO flag is present, the driver can wait for
block I/O operations, if __GFP_FS flag is present, the driver can wait on
operations involving the filesystem.

dm-bufio tested for __GFP_IO. However, dm-bufio can run on a loop block
device that makes calls into the filesystem. If __GFP_IO is present and
__GFP_FS isn't, dm-bufio could still block on filesystem operations if it
runs on a loop block device.

The change from __GFP_IO to __GFP_FS supposedly fixes one observed (though
unreproducible) deadlock involving dm-bufio and loop device.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-10-17 01:40:23 -04:00
Linus Torvalds
0429fbc0bd Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
Pull percpu consistent-ops changes from Tejun Heo:
 "Way back, before the current percpu allocator was implemented, static
  and dynamic percpu memory areas were allocated and handled separately
  and had their own accessors.  The distinction has been gone for many
  years now; however, the now duplicate two sets of accessors remained
  with the pointer based ones - this_cpu_*() - evolving various other
  operations over time.  During the process, we also accumulated other
  inconsistent operations.

  This pull request contains Christoph's patches to clean up the
  duplicate accessor situation.  __get_cpu_var() uses are replaced with
  with this_cpu_ptr() and __this_cpu_ptr() with raw_cpu_ptr().

  Unfortunately, the former sometimes is tricky thanks to C being a bit
  messy with the distinction between lvalues and pointers, which led to
  a rather ugly solution for cpumask_var_t involving the introduction of
  this_cpu_cpumask_var_ptr().

  This converts most of the uses but not all.  Christoph will follow up
  with the remaining conversions in this merge window and hopefully
  remove the obsolete accessors"

* 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (38 commits)
  irqchip: Properly fetch the per cpu offset
  percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t -fix
  ia64: sn_nodepda cannot be assigned to after this_cpu conversion. Use __this_cpu_write.
  percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t
  Revert "powerpc: Replace __get_cpu_var uses"
  percpu: Remove __this_cpu_ptr
  clocksource: Replace __this_cpu_ptr with raw_cpu_ptr
  sparc: Replace __get_cpu_var uses
  avr32: Replace __get_cpu_var with __this_cpu_write
  blackfin: Replace __get_cpu_var uses
  tile: Use this_cpu_ptr() for hardware counters
  tile: Replace __get_cpu_var uses
  powerpc: Replace __get_cpu_var uses
  alpha: Replace __get_cpu_var
  ia64: Replace __get_cpu_var uses
  s390: cio driver &__get_cpu_var replacements
  s390: Replace __get_cpu_var uses
  mips: Replace __get_cpu_var uses
  MIPS: Replace __get_cpu_var uses in FPU emulator.
  arm: Replace __this_cpu_ptr with raw_cpu_ptr
  ...
2014-10-15 07:48:18 +02:00
Jan-Simon Möller
b610626523 crypto, dm: LLVMLinux: Remove VLAIS usage from dm-crypt
Replaced the use of a Variable Length Array In Struct (VLAIS) with a C99
compliant equivalent. This patch allocates the appropriate amount of memory
using a char array using the SHASH_DESC_ON_STACK macro.

The new code can be compiled with both gcc and clang.

Signed-off-by: Jan-Simon Möller <dl9pf@gmx.de>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Reviewed-by: Mark Charlebois <charlebm@gmail.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Cc: pageexec@freemail.hu
Cc: gmazyland@gmail.com
Cc: "David S. Miller" <davem@davemloft.net>
2014-10-14 10:51:23 +02:00
NeilBrown
6c144d3164 md: move EXPORT_SYMBOL to after function in md.c
Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-14 13:08:29 +11:00
NeilBrown
2cbbca5e7c md: discard PRINT_RAID_DEBUG ioctl
All the interesting information printed by this ioctl
is provided in /proc/mdstat and/or sysfs.
So it isn't needed and isn't used and would be best if it didn't
exist.

Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-14 13:08:29 +11:00
NeilBrown
403df47888 md: remove MD_BUG()
Most of the places that call this are doing so pointlessly.
A couple of the others a best replaced with WARN_ON().

Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-14 13:08:29 +11:00
NeilBrown
3adc28d85f md: clean up 'exit' labels in md_ioctl().
There are 4 labels and we only really need two.

Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-14 13:08:29 +11:00
NeilBrown
326eb17d73 md: remove unnecessary test for MD_MAJOR in md_ioctl()
unknown ioctls no longer get this deep into md_ioctl since
md_ioctl_valid() was introduced in 3.14.
So remove the test and the misleading comment.

Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-14 13:08:29 +11:00
NeilBrown
e1960f8c5c md: don't allow "-sync" to be set for device in an active array.
If an array is active, devices can be marked 'faulty', but simply
removing the 'sync' flag is wrong.  That only makes sense
for an array which is not active (and is probably only useful
for testing anyway).

Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-14 13:08:29 +11:00
NeilBrown
f72ffdd686 md: remove unwanted white space from md.c
My editor shows much of this is RED.

Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-14 13:08:29 +11:00
NeilBrown
ac05f25669 md: don't start resync thread directly from md thread.
The main 'md' thread is needed for processing writes, so if it blocks
write requests could be delayed.

Starting a new thread requires some GFP_KERNEL allocations and so can
wait for writes to complete.  This can deadlock.

So instead, ask a workqueue to start the sync thread.
There is no particular rush for this to happen, so any work queue
will do.

MD_RECOVERY_RUNNING is used to ensure only one thread is started.

Reported-by: BillStuff <billstuff2001@sbcglobal.net>
Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-14 13:08:28 +11:00
NeilBrown
8b1afc3d67 md: Just use RCU when checking for overlap between arrays.
We don't really need the full mddev_lock here, and having to
drop it is messy.
RCU is enough to protect these lists.

Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-14 13:08:28 +11:00
Chao Yu
50bd377405 md: avoid potential long delay under pers_lock
printk may cause long time lapse if value of printk_delay in sysctl is
configured large by user. If register_md_personality takes long time to print in
spinlock pers_lock, we may encounter high CPU usage rate when there are other
pers_lock competitors who may be blocked to spin.
We can avoid this condition by moving printk out of coverage of pers_lock
spinlock.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-14 13:08:28 +11:00
NeilBrown
0638bb0e73 md: simplify export_array()
We don't really need that for_each loop, or those MD_BUGs.

Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-14 13:08:28 +11:00
NeilBrown
4878e9eb88 md: discard find_rdev_nr in favour of find_rdev_nr_rcu
Having both is a waste - just use the one.

Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-14 13:08:28 +11:00
NeilBrown
1967cd5616 md: use wait_event() to simplify md_super_wait()
md_super_wait is really just wait_event() open-coded.
So use the macro instead.

Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-14 13:08:28 +11:00
NeilBrown
9ba3b7f5d0 md: be more relaxed about stopping an array which isn't started.
In general we don't allow an array to be stopped if it is in use.
However if the array hasn't really been started yet, then any
apparent use is an anomily, probably due to 'udev' or similar
having a look to see what is there.

This means that if something goes wrong while assembling an array
it cannot reliably be un-assembled - STOP_ARRAY could fail.
There is no value here, so change do_md_stop() to succeed
despite concurrent opens if the array has not yet been
activated.  i.e. if ->pers is NULL.

Reported-by: "Baldysiak, Pawel" <pawel.baldysiak@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-14 13:08:28 +11:00
NeilBrown
c95e6385e8 md/raid1: process_checks doesn't use its return value.
process_checks() always returns '0', so change it to 'void'.

Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-14 13:08:28 +11:00
Markus Stockhausen
b8e6a15a1a md/raid5: fix init_stripe() inconsistencies
raid5: fix init_stripe() inconsistencies

1) remove_hash() is not necessary. We will only be called right after
   get_free_stripe(). There we have already a call to remove_hash().

2) Tracing prints out the sector of the freed stripe and not the sector
   that we want to initialize.

Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-14 13:08:28 +11:00
NeilBrown
c4796e215f md/raid10: another memory leak due to reshape.
Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-14 13:08:28 +11:00
Linus Torvalds
faafcba3b5 Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
 "The main changes in this cycle were:

   - Optimized support for Intel "Cluster-on-Die" (CoD) topologies (Dave
     Hansen)

   - Various sched/idle refinements for better idle handling (Nicolas
     Pitre, Daniel Lezcano, Chuansheng Liu, Vincent Guittot)

   - sched/numa updates and optimizations (Rik van Riel)

   - sysbench speedup (Vincent Guittot)

   - capacity calculation cleanups/refactoring (Vincent Guittot)

   - Various cleanups to thread group iteration (Oleg Nesterov)

   - Double-rq-lock removal optimization and various refactorings
     (Kirill Tkhai)

   - various sched/deadline fixes

  ... and lots of other changes"

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (72 commits)
  sched/dl: Use dl_bw_of() under rcu_read_lock_sched()
  sched/fair: Delete resched_cpu() from idle_balance()
  sched, time: Fix build error with 64 bit cputime_t on 32 bit systems
  sched: Improve sysbench performance by fixing spurious active migration
  sched/x86: Fix up typo in topology detection
  x86, sched: Add new topology for multi-NUMA-node CPUs
  sched/rt: Use resched_curr() in task_tick_rt()
  sched: Use rq->rd in sched_setaffinity() under RCU read lock
  sched: cleanup: Rename 'out_unlock' to 'out_free_new_mask'
  sched: Use dl_bw_of() under RCU read lock
  sched/fair: Remove duplicate code from can_migrate_task()
  sched, mips, ia64: Remove __ARCH_WANT_UNLOCKED_CTXSW
  sched: print_rq(): Don't use tasklist_lock
  sched: normalize_rt_tasks(): Don't use _irqsave for tasklist_lock, use task_rq_lock()
  sched: Fix the task-group check in tg_has_rt_tasks()
  sched/fair: Leverage the idle state info when choosing the "idlest" cpu
  sched: Let the scheduler see CPU idle states
  sched/deadline: Fix inter- exclusive cpusets migrations
  sched/deadline: Clear dl_entity params when setscheduling to different class
  sched/numa: Kill the wrong/dead TASK_DEAD check in task_numa_fault()
  ...
2014-10-13 16:23:15 +02:00
Pavitra Kumar
a3f2af2547 dm stripe: fix potential for leak in stripe_ctr error path
Fix a potential struct stripe_c leak that would occur if the
chunk_size exceeded the maximum allowed by dm_set_target_max_io_len
(UINT_MAX).  However, in practice there is no possibility of this
occuring given that chunk_size is of type uint32_t.  But it is good to
fix this to future-proof in case dm_set_target_max_io_len's
implementation were to change.

Signed-off-by: Pavitra Kumar <pavitrak@nvidia.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-10-10 22:05:18 -04:00
NeilBrown
3fd83717e4 md: use set_bit/clear_bit instead of shift/mask for bi_flags changes.
Using {set,clear}_bit is more consistent than shifting and masking.

No functional change.

Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-09 10:07:04 +11:00
NeilBrown
5965b642ff md/raid1: minor typos and reformatting.
Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-09 10:07:04 +11:00
NeilBrown
4b5060ddae md/bitmap: always wait for writes on unplug.
If two threads call bitmap_unplug at the same time, then
one might schedule all the writes, and the other might
decide that it doesn't need to wait.  But really it does.

It rarely hurts to wait when it isn't absolutely necessary,
and the current code doesn't really focus on 'absolutely necessary'
anyway.  So just wait always.

This can potentially lead to data corruption if a crash happens
at an awkward time and data was written before the bitmap was
updated.  It is very unlikely, but this should go to -stable
just to be safe.  Appropriate for any -stable.

Signed-off-by: NeilBrown <neilb@suse.de>
Cc: stable@vger.kernel.org (please delay until 3.18 is released)
2014-10-09 10:07:04 +11:00
Alexey Khoroshilov
56ec16cb1e dm log userspace: fix memory leak in dm_ulog_tfr_init failure path
If cn_add_callback() fails in dm_ulog_tfr_init(), it does not
deallocate prealloced memory but calls cn_del_callback().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-10-05 20:03:38 -04:00
Mikulas Patocka
0e825862f3 dm bufio: when done scanning return from __scan immediately
When __scan frees the required number of buffer entries that the
shrinker requested (nr_to_scan becomes zero) it must return.  Before
this fix the __scan code exited only the inner loop and continued in the
outer loop -- which could result in reduced performance due to extra
buffers being freed (e.g. unnecessarily evicted thinp metadata needing
to be synchronously re-read into bufio's cache).

Also, move dm_bufio_cond_resched to __scan's inner loop, so that
iterating the bufio client's lru lists doesn't result in scheduling
latency.

Reported-by: Joe Thornber <thornber@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 3.2+
2014-10-05 20:03:37 -04:00
Joe Thornber
eb76faf53b dm bufio: update last_accessed when relinking a buffer
The 'last_accessed' member of the dm_buffer structure was only set when
the the buffer was created.  This led to each buffer being discarded
after dm_bufio_max_age time even if it was used recently.  In practice
this resulted in all thinp metadata being evicted soon after being read
-- this is particularly problematic for metadata intensive workloads
like multithreaded small random IO.

'last_accessed' is now updated each time the buffer is moved to the head
of the LRU list, so the buffer is now properly discarded if it was not
used in dm_bufio_max_age time.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # v3.2+
2014-10-05 20:03:37 -04:00
Heinz Mauelshagen
48cf06bc5f dm raid: add discard support for RAID levels 4, 5 and 6
In case of RAID levels 4, 5 and 6 we have to verify each RAID members'
ability to zero data on discards to avoid stripe data corruption -- if
discard_zeroes_data is not set for each RAID member discard support must
be disabled.  But given the uncertainty of whether or not a RAID member
properly supports zeroing data on discard we require the user to
explicitly allow discard support on RAID levels 4, 5, and 6 by setting
a dm-raid module paramter, e.g.: dm-raid.devices_handle_discard_safely=Y
Otherwise, discards could cause data corruption on RAID4/5/6.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-10-05 20:03:36 -04:00
Heinz Mauelshagen
75b8e04bbf dm raid: add discard support for RAID levels 1 and 10
Discard support is not enabled for RAID levels 4, 5, and 6 at this time
due to concerns about unreliable discard_zeroes_data support on some
hardware.  Otherwise, discards could cause stripe data corruption
(classic example of bad apples spoiling the bunch).

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-10-05 20:03:36 -04:00
Benjamin Marzinski
86f1152b11 dm: allow active and inactive tables to share dm_devs
Until this change, when loading a new DM table, DM core would re-open
all of the devices in the DM table.  Now, DM core will avoid redundant
device opens (and closes when destroying the old table) if the old
table already has a device open using the same mode.  This is achieved
by managing reference counts on the table_devices that DM core now
stores in the mapped_device structure (rather than in the dm_table
structure).  So a mapped_device's active and inactive dm_tables' dm_dev
lists now just point to the dm_devs stored in the mapped_device's
table_devices list.

This improvement in DM core's device reference counting has the
side-effect of fixing a long-standing limitation of the multipath
target: a DM multipath table couldn't include any paths that were unusable
(failed).  For example: if all paths have failed and you add a new,
working, path to the table; you can't use it since the table load would
fail due to it still containing failed paths.  Now a re-load of a
multipath table can include failed devices and when those devices become
active again they can be used instantly.

The device list code in dm.c isn't a straight copy/paste from the code in
dm-table.c, but it's very close (aside from some variable renames).  One
subtle difference is that find_table_device for the tables_devices list
will only match devices with the same name and mode.  This is because we
don't want to upgrade a device's mode in the active table when an
inactive table is loaded.

Access to the mapped_device structure's tables_devices list requires a
mutex (tables_devices_lock), so that tables cannot be created and
destroyed concurrently.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-10-05 20:03:35 -04:00
Benjamin Marzinski
1f27197247 dm mpath: stop queueing IO when no valid paths exist
'queue_io' is set so that IO is queued while paths are being
initialized.  Clear queue_io in __choose_pgpath if there are no valid
paths, since there are obviously no paths that can be initialized.
Otherwise IOs to the device will back up.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-10-05 20:03:35 -04:00
Junichi Nomura
3d8aab2d2c dm: use bioset_create_nobvec()
Since DM core uses bio_clone_fast() for both bio-based and request-based
DM devices there is no need for DM's bioset to have a bvec mempool.

With this patch, on arch with 4KB page for example, memory usage will be
reduced by 64KB for each bio-based DM device and 1MB for each
request-based DM device.

For example, when you create 10,000 bio-based DM devices and 1,000
request-based DM devices, memory usage of biovec under no load is:
  # grep biovec /proc/slabinfo

  biovec-256        418068 418068   4096  ...
  biovec-128             0      0   2048  ...
  biovec-64              0      0   1024  ...
  biovec-16              0      0    256  ...

With this patch series applied, the usage becomes:
  # grep biovec /proc/slabinfo

  biovec-256           116    116   4096  ...
  biovec-128             0      0   2048  ...
  biovec-64              0      0   1024  ...
  biovec-16              0      0    256  ...

So 4096 * (418068 - 116) = 1.6GB of memory is saved in this example.

Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-10-05 20:03:34 -04:00
Junichi Nomura
997782735c dm: remove nr_iovecs parameter from alloc_tio()
alloc_tio() uses bio_alloc_bioset() to allocate a clone-bio for a bio.
alloc_tio() takes the number of bvecs to allocate for the clone-bio.
However, with v3.14's immutable biovec changes DM now uses
__bio_clone_fast() and no longer needs to allocate bvecs.

In practice, the 'nr_iovecs' passed to alloc_tio() is always effectively
0.  __clone_and_map_simple_bio() looked like it was passing non-zero
nr_iovecs, but its value was always within the range of inline bvecs and
no allocation actually happened.  If allocation happened, the BUG_ON() in
__bio_clone_fast() would've triggered.

Remove the nr_iovecs parameter from alloc_tio() to prevent possible
future bio_alloc_bioset() mis-use of a new bioset interface that will no
longer allow bvecs to be allocated.

Also fix extra whitespace before the __bio_clone_fast() call in
__clone_and_map_simple_bio().

Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-10-05 20:03:34 -04:00
Mike Snitzer
b277da0a8a block: disable entropy contributions for nonrot devices
Clear QUEUE_FLAG_ADD_RANDOM in all block drivers that set
QUEUE_FLAG_NONROT.

Historically, all block devices have automatically made entropy
contributions.  But as previously stated in commit e2e1a148 ("block: add
sysfs knob for turning off disk entropy contributions"):
    - On SSD disks, the completion times aren't as random as they
      are for rotational drives. So it's questionable whether they
      should contribute to the random pool in the first place.
    - Calling add_disk_randomness() has a lot of overhead.

There are more reliable sources for randomness than non-rotational block
devices.  From a security perspective it is better to err on the side of
caution than to allow entropy contributions from unreliable "random"
sources.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-10-04 10:55:32 -06:00
NeilBrown
8e0e99ba64 md/raid5: disable 'DISCARD' by default due to safety concerns.
It has come to my attention (thanks Martin) that 'discard_zeroes_data'
is only a hint.  Some devices in some cases don't do what it
says on the label.

The use of DISCARD in RAID5 depends on reads from discarded regions
being predictably zero.  If a write to a previously discarded region
performs a read-modify-write cycle it assumes that the parity block
was consistent with the data blocks.  If all were zero, this would
be the case.  If some are and some aren't this would not be the case.
This could lead to data corruption after a device failure when
data needs to be reconstructed from the parity.

As we cannot trust 'discard_zeroes_data', ignore it by default
and so disallow DISCARD on all raid4/5/6 arrays.

As many devices are trustworthy, and as there are benefits to using
DISCARD, add a module parameter to over-ride this caution and cause
DISCARD to work if discard_zeroes_data is set.

If a site want to enable DISCARD on some arrays but not on others they
should select DISCARD support at the filesystem level, and set the
raid456 module parameter.
    raid456.devices_handle_discard_safely=Y

As this is a data-safety issue, I believe this patch is suitable for
-stable.
DISCARD support for RAID456 was added in 3.7

Cc: Shaohua Li <shli@kernel.org>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Heinz Mauelshagen <heinzm@redhat.com>
Cc: stable@vger.kernel.org (3.7+)
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Fixes: 620125f2bf
Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-02 13:45:00 +10:00
Linus Torvalds
a90e41e228 Bugfixes for md/raid1
particularly, but not only, fixing new "resync" code.
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Merge tag 'md/3.17-more-fixes' of git://git.neil.brown.name/md

Pull bugfixes for md/raid1 from Neil Brown:
 "It is amazing how much easier it is to find bugs when you know one is
  there.  Two bug reports resulted in finding 7 bugs!

  All are tagged for -stable.  Those that can't cause (rare) data
  corruption, cause lockups.

  Particularly, but not only, fixing new "resync" code"

* tag 'md/3.17-more-fixes' of git://git.neil.brown.name/md:
  md/raid1: fix_read_error should act on all non-faulty devices.
  md/raid1: count resync requests in nr_pending.
  md/raid1: update next_resync under resync_lock.
  md/raid1: Don't use next_resync to determine how far resync has progressed
  md/raid1: make sure resync waits for conflicting writes to complete.
  md/raid1: clean up request counts properly in close_sync()
  md/raid1:  be more cautious where we read-balance during resync.
  md/raid1: intialise start_next_window for READ case to avoid hang
2014-09-24 08:53:33 -07:00
NeilBrown
b8cb6b4c12 md/raid1: fix_read_error should act on all non-faulty devices.
If a devices is being recovered it is not InSync and is not Faulty.

If a read error is experienced on that device, fix_read_error()
will be called, but it ignores non-InSync devices.  So it will
neither fix the error nor fail the device.

It is incorrect that fix_read_error() ignores non-InSync devices.
It should only ignore Faulty devices.  So fix it.

This became a bug when we allowed reading from a device that was being
recovered.  It is suitable for any subsequent -stable kernel.

Fixes: da8840a747
Cc: stable@vger.kernel.org (v3.5+)
Reported-by: Alexander Lyakas <alex.bolshoy@gmail.com>
Tested-by: Alexander Lyakas <alex.bolshoy@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2014-09-22 11:26:01 +10:00
NeilBrown
34e97f1701 md/raid1: count resync requests in nr_pending.
Both normal IO and resync IO can be retried with reschedule_retry()
and so be counted into ->nr_queued, but only normal IO gets counted in
->nr_pending.

Before the recent improvement to RAID1 resync there could only
possibly have been one or the other on the queue.  When handling a
read failure it could only be normal IO.  So when handle_read_error()
called freeze_array() the fact that freeze_array only compares
->nr_queued against ->nr_pending was safe.

But now that these two types can interleave, we can have both normal
and resync IO requests queued, so we need to count them both in
nr_pending.

This error can lead to freeze_array() hanging if there is a read
error, so it is suitable for -stable.

Fixes: 79ef3a8aa1
cc: stable@vger.kernel.org (v3.13+)
Reported-by: Brassow Jonathan <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2014-09-22 11:26:01 +10:00
NeilBrown
c2fd4c94de md/raid1: update next_resync under resync_lock.
raise_barrier() uses next_resync as part of its calculations, so it
really should be updated first, instead of afterwards.

next_resync is always used under resync_lock so update it under
resync lock to, just before it is used.  That is safest.

This could cause normal IO and resync IO to interact badly so
it suitable for -stable.

Fixes: 79ef3a8aa1
cc: stable@vger.kernel.org (v3.13+)
Signed-off-by: NeilBrown <neilb@suse.de>
2014-09-22 11:26:01 +10:00