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authorAlasdair G Kergon <agk@redhat.com>2011-10-31 20:19:04 +0000
committerAlasdair G Kergon <agk@redhat.com>2011-10-31 20:19:04 +0000
commit36a0456fbf2d9680bf9af81b39daf4a8e22cb1b8 (patch)
treea19af18640d538e8357c195e6b4c77d0f6c92391 /drivers/md/dm.c
parentcc6cbe141a20f6d876b161b60af38d93935bfa85 (diff)
dm table: add immutable feature
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>
Diffstat (limited to 'drivers/md/dm.c')
-rw-r--r--drivers/md/dm.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 2fe3017ba97..9836324e211 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -140,6 +140,8 @@ struct mapped_device {
/* Protect queue and type against concurrent access. */
struct mutex type_lock;
+ struct target_type *immutable_target_type;
+
struct gendisk *disk;
char name[16];
@@ -2096,6 +2098,8 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
write_lock_irqsave(&md->map_lock, flags);
old_map = md->map;
md->map = t;
+ md->immutable_target_type = dm_table_get_immutable_target_type(t);
+
dm_table_set_restrictions(t, q, limits);
if (merge_is_optional)
set_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
@@ -2166,6 +2170,11 @@ unsigned dm_get_md_type(struct mapped_device *md)
return md->type;
}
+struct target_type *dm_get_immutable_target_type(struct mapped_device *md)
+{
+ return md->immutable_target_type;
+}
+
/*
* Fully initialize a request-based queue (->elevator, ->request_fn, etc).
*/