linux.git/drivers/md/dm-thin.c, branch v3.12

dm thin: do not expose non-zero discard limits if discards disabled

2013-09-23T14:42:06+00:00

Fix issue where the block layer would stack the discard limits of the
pool's data device even if the "ignore_discard" pool feature was
specified.

The pool and thin device(s) still had discards disabled because the
QUEUE_FLAG_DISCARD request_queue flag wasn't set.  But to avoid user
confusion when "ignore_discard" is used: both the pool device and the
thin device(s) have zeroes for all discard limits.

Also, always set discard_zeroes_data_unsupported in targets because they
should never advertise the 'discard_zeroes_data' capability (even if the
pool's data device supports it).

Signed-off-by: Mike Snitzer 
Acked-by: Joe Thornber

dm thin: always return -ENOSPC if no_free_space is set

2013-09-06T00:46:06+00:00

If pool has 'no_free_space' set it means a previous allocation already
determined the pool has no free space (and failed that allocation with
-ENOSPC).  By always returning -ENOSPC if 'no_free_space' is set, we do
not allow the pool to oscillate between allocating blocks and then not.

But a side-effect of this determinism is that if a user wants to be able
to allocate new blocks they'll need to reload the pool's table (to clear
the 'no_free_space' flag).  This reload will happen automatically if the
pool's data volume is resized.  But if the user takes action to free a
lot of space by deleting snapshot volumes, etc the pool will no longer
allow data allocations to continue without an intervening table reload.

Signed-off-by: Mike Snitzer 
Acked-by: Joe Thornber 
Signed-off-by: Alasdair G Kergon

dm thin: set pool read-only if breaking_sharing fails block allocation

2013-09-06T00:46:06+00:00

break_sharing() now handles an arbitrary alloc_data_block() error
the same way as provision_block(): marks pool read-only and errors the
cell.

Signed-off-by: Mike Snitzer 
Acked-by: Joe Thornber 
Signed-off-by: Alasdair G Kergon

dm thin: prefix pool error messages with pool device name

2013-09-06T00:46:05+00:00

Useful to know which pool is experiencing the error.

Signed-off-by: Mike Snitzer 
Acked-by: Joe Thornber 
Signed-off-by: Alasdair G Kergon

dm thin: fix stacking of geometry limits

2013-08-23T13:02:14+00:00

Do not blindly override the queue limits (specifically io_min and
io_opt).  Allow traditional stacking of these limits if io_opt is a
factor of the thin-pool's data block size.

Without this patch mkfs.xfs does not recognize the thin device's
provided limits as a useful geometry (e.g. raid) so these hints are
ignored.  This was due to setting io_min to a useless value.

Signed-off-by: Mike Snitzer 
Signed-off-by: Alasdair G Kergon 
Acked-by: Joe Thornber

dm thin: fix metadata dev resize detection

2013-05-19T17:57:50+00:00

Fix detection of the need to resize the dm thin metadata device.

The code incorrectly tried to extend the metadata device when it
didn't need to due to a merging error with patch 24347e9 ("dm thin:
detect metadata device resizing").

  device-mapper: transaction manager: couldn't open metadata space map
  device-mapper: thin metadata: tm_open_with_sm failed
  device-mapper: thin: aborting transaction failed
  device-mapper: thin: switching pool to failure mode

Signed-off-by: Alasdair G Kergon

dm thin: generate event when metadata threshold passed

2013-05-10T13:37:21+00:00

Generate a dm event when the amount of remaining thin pool metadata
space falls below a certain level.

The threshold is taken to be a quarter of the size of the metadata
device with a minimum threshold of 4MB.

Signed-off-by: Joe Thornber 
Signed-off-by: Alasdair G Kergon

dm thin: detect metadata device resizing

2013-05-10T13:37:19+00:00

Allow the dm thin pool metadata device to be extended.

Whenever a pool is resumed, detect whether the size of the metadata
device has increased, and if so, extend the metadata to use the new
space.

Signed-off-by: Joe Thornber 
Signed-off-by: Alasdair G Kergon

dm thin: open dev read only when possible

2013-05-10T13:37:19+00:00

If a thin pool is created in read-only-metadata mode then only open the
metadata device read-only.

Previously it was always opened with FMODE_READ | FMODE_WRITE.

(Note that dm_get_device() still allows read-only dm devices to be used
read-write at the moment: If I create a read-only linear device for the
metadata, via dmsetup load --readonly, then I can still create a rw pool
out of it.)

Signed-off-by: Joe Thornber 
Signed-off-by: Alasdair G Kergon

dm thin: refactor data dev resize

2013-05-10T13:37:18+00:00

Refactor device size functions in preparation for similar metadata
device resizing functions.

Signed-off-by: Joe Thornber 
Signed-off-by: Alasdair G Kergon