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authorJoe Thornber <ejt@redhat.com>2013-05-10 14:37:20 +0100
committerAlasdair G Kergon <agk@redhat.com>2013-05-10 14:37:20 +0100
commit7c3d3f2a87b01ff167a5f048285d5e3dee920235 (patch)
tree44b483cd78221e412b314c872cb5ddedfdfd2abe
parent24347e9595704464f62a4ed8f46abf62b4c79cdd (diff)
downloadlinux-stericsson-7c3d3f2a87b01ff167a5f048285d5e3dee920235.tar.gz
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>
-rw-r--r--drivers/md/persistent-data/dm-space-map-disk.c3
-rw-r--r--drivers/md/persistent-data/dm-space-map-metadata.c6
-rw-r--r--drivers/md/persistent-data/dm-space-map.h23
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 */