linux-toradex.git/drivers/md/dm-thin.c, branch v4.1.10

dm thin: allocate the cell_sort_array dynamically

2015-08-03T16:29:06+00:00

commit a822c83e47d97cdef38c4352e1ef62d9f46cfe98 upstream.

Given the pool's cell_sort_array holds 8192 pointers it triggers an
order 5 allocation via kmalloc.  This order 5 allocation is prone to
failure as system memory gets more fragmented over time.

Fix this by allocating the cell_sort_array using vmalloc.

Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm thin: fix to consistently zero-fill reads to unprovisioned blocks

2015-02-27T14:59:12+00:00

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 
Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer 
Cc: stable@vger.kernel.org

Merge tag 'dm-3.20-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

2015-02-13T00:36:31+00:00

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

dm: use time_in_range() and time_after()

2015-02-09T18:06:48+00:00

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 
Signed-off-by: Mike Snitzer

dm thin: don't allow messages to be sent to a pool target in READ_ONLY or FAIL mode

2015-01-28T15:00:34+00:00

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 
Signed-off-by: Mike Snitzer 
Cc: stable@vger.kernel.org

dm thin: fix crash by initializing thin device's refcount and completion earlier

2014-12-17T17:06:25+00:00

Commit 80e96c5484be ("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: [] __wake_up_common+0x2b/0x90

 kernel: Call Trace:
 kernel: [] __wake_up_locked+0x13/0x20
 kernel: [] complete+0x37/0x50
 kernel: [] thin_put+0x20/0x30 [dm_thin_pool]
 kernel: [] do_worker+0x667/0x870 [dm_thin_pool]
 kernel: [] ? __schedule+0x3ac/0x9a0
 kernel: [] process_one_work+0x14f/0x400
 kernel: [] worker_thread+0x6b/0x490
 kernel: [] ? rescuer_thread+0x260/0x260
 kernel: [] kthread+0xdb/0x100
 kernel: [] ? kthread_create_on_node+0x170/0x170
 kernel: [] ret_from_fork+0x7c/0xb0
 kernel: [] ? 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 
Signed-off-by: Mike Snitzer

dm thin: fix missing out-of-data-space to write mode transition if blocks are released

2014-12-17T16:59:36+00:00

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 
Signed-off-by: Mike Snitzer 
Cc: stable@vger.kernel.org

dm thin: fix inability to discard blocks when in out-of-data-space mode

2014-12-17T16:59:36+00:00

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 
Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer 
Cc: stable@vger.kernel.org

dm thin: fix pool_io_hints to avoid looking at max_hw_sectors

2014-11-21T17:54:23+00:00

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

dm thin: suspend/resume active thin devices when reloading thin-pool

2014-11-19T17:34:08+00:00

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 
Acked-by: Joe Thornber