diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-06-02 17:39:40 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-06-02 17:39:40 -0700 |
| commit | 912afc3616b94c5c4af584972c7f5903b53cf15a (patch) | |
| tree | 3edd4596fe53ce5bc8224b1cccd5d34dcac040a7 /drivers/md/dm-thin-metadata.h | |
| parent | 4fc3acf2918fa158dc651a0c824a23944e956919 (diff) | |
| parent | cc8394d86f045b86ff303d3c9e4ce47d97148951 (diff) | |
Merge tag 'dm-3.5-changes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm
Pull device-mapper updates from Alasdair G Kergon:
"Improve multipath's retrying mechanism in some defined circumstances
and provide a simple reserve/release mechanism for userspace tools to
access thin provisioning metadata while the pool is in use."
* tag 'dm-3.5-changes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm:
dm thin: provide userspace access to pool metadata
dm thin: use slab mempools
dm mpath: allow ioctls to trigger pg init
dm mpath: delay retry of bypassed pg
dm mpath: reduce size of struct multipath
Diffstat (limited to 'drivers/md/dm-thin-metadata.h')
| -rw-r--r-- | drivers/md/dm-thin-metadata.h | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/md/dm-thin-metadata.h b/drivers/md/dm-thin-metadata.h index ed4725e67c96..b88918ccdaf6 100644 --- a/drivers/md/dm-thin-metadata.h +++ b/drivers/md/dm-thin-metadata.h @@ -90,11 +90,18 @@ int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd, /* * Hold/get root for userspace transaction. + * + * The metadata snapshot is a copy of the current superblock (minus the + * space maps). Userland can access the data structures for READ + * operations only. A small performance hit is incurred by providing this + * copy of the metadata to userland due to extra copy-on-write operations + * on the metadata nodes. Release this as soon as you finish with it. */ -int dm_pool_hold_metadata_root(struct dm_pool_metadata *pmd); +int dm_pool_reserve_metadata_snap(struct dm_pool_metadata *pmd); +int dm_pool_release_metadata_snap(struct dm_pool_metadata *pmd); -int dm_pool_get_held_metadata_root(struct dm_pool_metadata *pmd, - dm_block_t *result); +int dm_pool_get_metadata_snap(struct dm_pool_metadata *pmd, + dm_block_t *result); /* * Actions on a single virtual device. |