diff options
| author | Joe Thornber <ejt@redhat.com> | 2013-05-10 14:37:20 +0100 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2013-05-10 14:37:20 +0100 |
| commit | 7c3d3f2a87b01ff167a5f048285d5e3dee920235 (patch) | |
| tree | 44b483cd78221e412b314c872cb5ddedfdfd2abe /drivers/md/persistent-data | |
| parent | 24347e9595704464f62a4ed8f46abf62b4c79cdd (diff) | |
dm persistent data: add threshold callback to space map
Add a threshold callback function to the persistent data space map
interface for a subsequent patch to use.
dm-thin and dm-cache are interested in knowing when they're getting
low on metadata or data blocks. This patch introduces a new method
for registering a callback against a threshold.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/persistent-data')
| -rw-r--r-- | drivers/md/persistent-data/dm-space-map-disk.c | 3 | ||||
| -rw-r--r-- | drivers/md/persistent-data/dm-space-map-metadata.c | 6 | ||||
| -rw-r--r-- | drivers/md/persistent-data/dm-space-map.h | 23 |
3 files changed, 29 insertions, 3 deletions
diff --git a/drivers/md/persistent-data/dm-space-map-disk.c b/drivers/md/persistent-data/dm-space-map-disk.c index f6d29e614ab7..e735a6d5a793 100644 --- a/drivers/md/persistent-data/dm-space-map-disk.c +++ b/drivers/md/persistent-data/dm-space-map-disk.c @@ -248,7 +248,8 @@ static struct dm_space_map ops = { .new_block = sm_disk_new_block, .commit = sm_disk_commit, .root_size = sm_disk_root_size, - .copy_root = sm_disk_copy_root + .copy_root = sm_disk_copy_root, + .register_threshold_callback = NULL }; struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm, diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c index 51ca9edef444..883b465794d4 100644 --- a/drivers/md/persistent-data/dm-space-map-metadata.c +++ b/drivers/md/persistent-data/dm-space-map-metadata.c @@ -391,7 +391,8 @@ static struct dm_space_map ops = { .new_block = sm_metadata_new_block, .commit = sm_metadata_commit, .root_size = sm_metadata_root_size, - .copy_root = sm_metadata_copy_root + .copy_root = sm_metadata_copy_root, + .register_threshold_callback = NULL }; /*----------------------------------------------------------------*/ @@ -513,7 +514,8 @@ static struct dm_space_map bootstrap_ops = { .new_block = sm_bootstrap_new_block, .commit = sm_bootstrap_commit, .root_size = sm_bootstrap_root_size, - .copy_root = sm_bootstrap_copy_root + .copy_root = sm_bootstrap_copy_root, + .register_threshold_callback = NULL }; /*----------------------------------------------------------------*/ diff --git a/drivers/md/persistent-data/dm-space-map.h b/drivers/md/persistent-data/dm-space-map.h index 1cbfc6b1638a..3e6d1153b7c4 100644 --- a/drivers/md/persistent-data/dm-space-map.h +++ b/drivers/md/persistent-data/dm-space-map.h @@ -9,6 +9,8 @@ #include "dm-block-manager.h" +typedef void (*dm_sm_threshold_fn)(void *context); + /* * struct dm_space_map keeps a record of how many times each block in a device * is referenced. It needs to be fixed on disk as part of the transaction. @@ -59,6 +61,15 @@ struct dm_space_map { */ int (*root_size)(struct dm_space_map *sm, size_t *result); int (*copy_root)(struct dm_space_map *sm, void *copy_to_here_le, size_t len); + + /* + * You can register one threshold callback which is edge-triggered + * when the free space in the space map drops below the threshold. + */ + int (*register_threshold_callback)(struct dm_space_map *sm, + dm_block_t threshold, + dm_sm_threshold_fn fn, + void *context); }; /*----------------------------------------------------------------*/ @@ -131,4 +142,16 @@ static inline int dm_sm_copy_root(struct dm_space_map *sm, void *copy_to_here_le return sm->copy_root(sm, copy_to_here_le, len); } +static inline int dm_sm_register_threshold_callback(struct dm_space_map *sm, + dm_block_t threshold, + dm_sm_threshold_fn fn, + void *context) +{ + if (sm->register_threshold_callback) + return sm->register_threshold_callback(sm, threshold, fn, context); + + return -EINVAL; +} + + #endif /* _LINUX_DM_SPACE_MAP_H */ |