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 <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Allow targets to override the 'supports flush' calculation.
Set 'flush_supported' if a target needs to receive flushes regardless of
whether or not its underlying devices have support.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch introduces a new variable split_discard_requests. It can be
set by targets so that discard requests are split on max_io_len
boundaries.
When split_discard_requests is not set, discard requests are only split on
boundaries between targets, as was the case before this patch.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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 <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Remove unused dm_flush_fn .flush target method from header.
This was left-over from the FLUSH/FUA conversion and is no longer used.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Introduce DM_TARGET_IMMUTABLE to indicate that the target type cannot be mixed
with any other target type, and once loaded into a device, it cannot be
replaced with a table containing a different type.
The thin provisioning pool device will use this.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Add a target feature flag DM_TARGET_ALWAYS_WRITEABLE to indicate that a target
does not support read-only mode.
The initial implementation of the thin provisioning target uses this.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Introduce the concept of a singleton table which contains exactly one target.
If a target type sets the DM_TARGET_SINGLETON feature bit device-mapper
will ensure that any table that includes that target contains no others.
The thin provisioning pool target uses this.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
printk_ratelimit() shares global ratelimiting state with all
other subsystems, so its usage is discouraged. Instead,
define and use dm's local state.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
If optional discard support in dm-crypt is enabled, discards requests
bypass the crypt queue and blocks of the underlying device are discarded.
For the read path, discarded blocks are handled the same as normal
ciphertext blocks, thus decrypted.
So if the underlying device announces discarded regions return zeroes,
dm-crypt must disable this flag because after decryption there is just
random noise instead of zeroes.
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Move multipath target argument parsing code into dm-table so other
targets can share it.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Permit a target to support discards regardless of whether or not all its
underlying devices do.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Now that unplugging is done differently, the unplug_fn callback is
never called, so it can be completely discarded.
Signed-off-by: NeilBrown <neilb@suse.de>
Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
DM currently implements congestion checking by checking on congestion
in each component device. For raid456 we need to also check if the
stripe cache is congested.
Add per-target congestion checker callback support.
Extending the target_callbacks structure with additional callback
functions allows for establishing multiple callbacks per-target (a
callback is also needed for unplug).
Cc: linux-raid@vger.kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Split max_io_len_target_boundary out of max_io_len so that the discard
support can make use of it without duplicating max_io_len code.
Avoiding max_io_len's split_io logic enables DM's discard support to
submit the entire discard request to a target. But discards must still
be split on target boundaries.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Allow discards to be passed through to linear mappings if at least one
underlying device supports it. Discards will be forwarded only to
devices that support them.
A target that supports discards should set num_discard_requests to
indicate how many times each discard request must be submitted to it.
Verify table's underlying devices support discards prior to setting the
associated DM device as capable of discards (via QUEUE_FLAG_DISCARD).
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Joe Thornber <thornber@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
'target_request_nr' is a more generic name that reflects the fact that
it will be used for both flush and discard support.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Remove unused parameters(start and len) of dm_get_device()
and fix the callers.
Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
When swapping a new table into place, retain the old table until
its replacement is in place.
An old check for an empty table is removed because this is enforced
in populate_table().
__unbind() becomes redundant when followed by __bind().
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
