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authorJoe Thornber <ejt@redhat.com>2014-09-17 10:17:39 +0100
committerMike Snitzer <snitzer@redhat.com>2014-11-10 15:25:30 -0500
commit5f274d886598c9fd26d2499bf3f68306f170e9db (patch)
treeaf0ded19382c65e832ea51e2b01efb40581c81dd /drivers/md
parentf1afb36a6102b52949c2c6d8eb250eddcce3fc5f (diff)
dm bio prison: introduce support for locking ranges of blocks
Ranges will be placed in the same cell if they overlap. Range locking is a prerequisite for more efficient multi-block discard support in both the cache and thin-provisioning targets. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/dm-bio-prison.c4
-rw-r--r--drivers/md/dm-bio-prison.h12
-rw-r--r--drivers/md/dm-cache-target.c3
-rw-r--r--drivers/md/dm-thin.c6
4 files changed, 16 insertions, 9 deletions
diff --git a/drivers/md/dm-bio-prison.c b/drivers/md/dm-bio-prison.c
index bbe22a5dc06b..be065300e93c 100644
--- a/drivers/md/dm-bio-prison.c
+++ b/drivers/md/dm-bio-prison.c
@@ -95,10 +95,10 @@ static int cmp_keys(struct dm_cell_key *lhs,
if (lhs->dev > rhs->dev)
return 1;
- if (lhs->block < rhs->block)
+ if (lhs->block_end <= rhs->block_begin)
return -1;
- if (lhs->block > rhs->block)
+ if (lhs->block_begin >= rhs->block_end)
return 1;
return 0;
diff --git a/drivers/md/dm-bio-prison.h b/drivers/md/dm-bio-prison.h
index b03988667740..74cf01144b1f 100644
--- a/drivers/md/dm-bio-prison.h
+++ b/drivers/md/dm-bio-prison.h
@@ -23,11 +23,14 @@
*/
struct dm_bio_prison;
-/* FIXME: this needs to be more abstract */
+/*
+ * Keys define a range of blocks within either a virtual or physical
+ * device.
+ */
struct dm_cell_key {
int virtual;
dm_thin_id dev;
- dm_block_t block;
+ dm_block_t block_begin, block_end;
};
/*
@@ -59,7 +62,7 @@ void dm_bio_prison_free_cell(struct dm_bio_prison *prison,
struct dm_bio_prison_cell *cell);
/*
- * Creates, or retrieves a cell for the given key.
+ * Creates, or retrieves a cell that overlaps the given key.
*
* Returns 1 if pre-existing cell returned, zero if new cell created using
* @cell_prealloc.
@@ -70,7 +73,8 @@ int dm_get_cell(struct dm_bio_prison *prison,
struct dm_bio_prison_cell **cell_result);
/*
- * An atomic op that combines retrieving a cell, and adding a bio to it.
+ * An atomic op that combines retrieving or creating a cell, and adding a
+ * bio to it.
*
* Returns 1 if the cell was already held, 0 if @inmate is the new holder.
*/
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 69de8b43ca12..890e2fff4074 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -436,7 +436,8 @@ static void build_key(dm_oblock_t oblock, struct dm_cell_key *key)
{
key->virtual = 0;
key->dev = 0;
- key->block = from_oblock(oblock);
+ key->block_begin = from_oblock(oblock);
+ key->block_end = key->block_begin + 1ULL;
}
/*
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index fb05f6a4bbfd..8c5504c0e894 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -115,7 +115,8 @@ static void build_data_key(struct dm_thin_device *td,
{
key->virtual = 0;
key->dev = dm_thin_dev_id(td);
- key->block = b;
+ key->block_begin = b;
+ key->block_end = b + 1ULL;
}
static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
@@ -123,7 +124,8 @@ static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
{
key->virtual = 1;
key->dev = dm_thin_dev_id(td);
- key->block = b;
+ key->block_begin = b;
+ key->block_end = b + 1ULL;
}
/*----------------------------------------------------------------*/

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