linux.git/drivers/md/dm.c, branch v3.19

dm: fix handling of multiple internal suspends

2015-01-24T19:50:08+00:00

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 
Signed-off-by: Mike Snitzer

dm: fix missed error code if .end_io isn't implemented by target_type

2014-12-17T17:31:13+00:00

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 
Signed-off-by: Mike Snitzer 
Fixes: 7eee4ae2db ("dm: disable WRITE SAME if it fails")
Cc: stable@vger.kernel.org

Merge branch 'for-3.19/drivers' of git://git.kernel.dk/linux-block

2014-12-13T22:22:26+00:00

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()
  ...

md: use generic io stats accounting functions to simplify io stat accounting

2014-11-24T15:05:16+00:00

Use generic io stats accounting help functions (generic_{start,end}_io_acct)
to simplify io stat accounting.

Signed-off-by: Gu Zheng 
Signed-off-by: Jens Axboe

dm: use rcu_dereference_protected instead of rcu_dereference

2014-11-24T01:32:45+00:00

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 
Signed-off-by: Eric Dumazet 
Fixes: 33423974bfc1 ("dm: Use rcu_dereference() for accessing rcu pointer")
Cc: Pranith Kumar 
[snitzer: allow lines longer than 80 columns, refine subject]
Signed-off-by: Mike Snitzer

dm: enhance internal suspend and resume interface

2014-11-19T17:31:17+00:00

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 
Acked-by: Joe Thornber

dm: add presuspend_undo hook to target_type

2014-11-19T16:24:59+00:00

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 
Acked-by: Joe Thornber

dm: return earlier from dm_blk_ioctl if target doesn't implement .ioctl

2014-11-19T16:24:56+00:00

No point checking if the device is suspended if the current target
doesn't even implement .ioctl

Signed-off-by: Mike Snitzer

dm: do not call dm_sync_table() when creating new devices

2014-11-10T20:25:29+00:00

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 
Reviewed-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer

dm: sparse: Annotate field with __rcu for checking

2014-11-10T20:25:29+00:00

Annotate the map field with __rcu since this is a rcu pointer which is checked
by sparse.

Signed-off-by: Pranith Kumar 
Signed-off-by: Paul E. McKenney 
Signed-off-by: Mike Snitzer