linux-stable.git/drivers/md/dm-snap.c, branch v3.8

dm: remove map_info

2012-12-21T20:23:41+00:00

This patch removes map_info from bio-based device mapper targets.
map_info is still used for request-based targets.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Alasdair G Kergon

dm snapshot: do not use map_context

2012-12-21T20:23:41+00:00

Eliminate struct map_info from dm-snap.

map_info->ptr was used in dm-snap to indicate if the bio was tracked.
If map_info->ptr was non-NULL, the bio was linked in tracked_chunk_hash.

This patch removes the use of map_info->ptr. We determine if the bio was
tracked based on hlist_unhashed(&c->node). If hlist_unhashed is true,
the bio is not tracked, if it is false, the bio is tracked.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Alasdair G Kergon

dm: move target request nr to dm_target_io

2012-12-21T20:23:39+00:00

This patch moves target_request_nr from map_info to dm_target_io and
makes it accessible with dm_bio_get_target_request_nr.

This patch is a preparation for the next patch that removes map_info.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Alasdair G Kergon

dm snapshot: use per_bio_data

2012-12-21T20:23:38+00:00

Replace tracked_chunk_pool with per_bio_data in dm-snap.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Alasdair G Kergon

dm snapshot: optimize track_chunk

2012-12-21T20:23:33+00:00

track_chunk is always called with interrupts enabled. Consequently, we
do not need to save and restore interrupt state in "flags" variable.
This patch changes spin_lock_irqsave to spin_lock_irq and
spin_unlock_irqrestore to spin_unlock_irq.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Alasdair G Kergon

dm thin: commit before gathering status

2012-07-27T14:08:16+00:00

Commit outstanding metadata before returning the status for a dm thin
pool so that the numbers reported are as up-to-date as possible.

The commit is not performed if the device is suspended or if
the DM_NOFLUSH_FLAG is supplied by userspace and passed to the target
through a new 'status_flags' parameter in the target's dm_status_fn.

The userspace dmsetup tool will support the --noflush flag with the
'dmsetup status' and 'dmsetup wait' commands from version 1.02.76
onwards.

Tested-by: Mike Snitzer 
Signed-off-by: Alasdair G Kergon

dm: support non power of two target max_io_len

2012-07-27T14:08:00+00:00

Remove the restriction that limits a target's specified maximum incoming
I/O size to be a power of 2.

Rename this setting from 'split_io' to the less-ambiguous 'max_io_len'.
Change it from sector_t to uint32_t, which is plenty big enough, and
introduce a wrapper function dm_set_target_max_io_len() to set it.
Use sector_div() to process it now that it is not necessarily a power of 2.

Signed-off-by: Mike Snitzer 
Signed-off-by: Alasdair G Kergon

dm snapshot: remove redundant assignment in merge fn

2012-07-27T14:07:59+00:00

Remove redundant bvm->bi_sector self-assignment in dm snapshot's
origin_merge().

Signed-off-by: Alasdair G Kergon

dm snapshot: skip reading origin when overwriting complete chunk

2011-08-02T11:32:04+00:00

If we write a full chunk in the snapshot, skip reading the origin device
because the whole chunk will be overwritten anyway.

This patch changes the snapshot write logic when a full chunk is written.
In this case:
  1. allocate the exception
  2. dispatch the bio (but don't report the bio completion to device mapper)
  3. write the exception record
  4. report bio completed

Callbacks must be done through the kcopyd thread, because callbacks must not
race with each other.  So we create two new functions:

  dm_kcopyd_prepare_callback: allocate a job structure and prepare the callback.
  (This function must not be called from interrupt context.)

  dm_kcopyd_do_callback: submit callback.
  (This function may be called from interrupt context.)

Performance test (on snapshots with 4k chunk size):
  without the patch:
    non-direct-io sequential write (dd):    17.7MB/s
    direct-io sequential write (dd):        20.9MB/s
    non-direct-io random write (mkfs.ext2): 0.44s

  with the patch:
    non-direct-io sequential write (dd):    26.5MB/s
    direct-io sequential write (dd):        33.2MB/s
    non-direct-io random write (mkfs.ext2): 0.27s

Signed-off-by: Mikulas Patocka 
Signed-off-by: Alasdair G Kergon

dm snapshot: style cleanups

2011-08-02T11:32:03+00:00

Coding style cleanups.

Signed-off-by: Alasdair G Kergon 
Signed-off-by: Jonathan Brassow