diff options
author | Alasdair G Kergon <agk@redhat.com> | 2011-10-31 16:19:00 -0400 |
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committer | Alasdair G Kergon <agk@redhat.com> | 2011-10-31 16:19:00 -0400 |
commit | 3791e2fc0e4b40d4188e79b0a99bfa6bce714a10 (patch) | |
tree | 2dc67f0593e1cb1f3dc07ff9883a03fe9edb4b2a /include | |
parent | 7f06965390e4a10fb6906c886324bfd0a96961be (diff) |
dm table: add singleton feature
Introduce the concept of a singleton table which contains exactly one target.
If a target type sets the DM_TARGET_SINGLETON feature bit device-mapper
will ensure that any table that includes that target contains no others.
The thin provisioning pool target uses this.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/device-mapper.h | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index 622678ccb5e..294e78a7fcc 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h | |||
@@ -128,10 +128,6 @@ void dm_put_device(struct dm_target *ti, struct dm_dev *d); | |||
128 | * Information about a target type | 128 | * Information about a target type |
129 | */ | 129 | */ |
130 | 130 | ||
131 | /* | ||
132 | * Target features | ||
133 | */ | ||
134 | |||
135 | struct target_type { | 131 | struct target_type { |
136 | uint64_t features; | 132 | uint64_t features; |
137 | const char *name; | 133 | const char *name; |
@@ -160,6 +156,16 @@ struct target_type { | |||
160 | struct list_head list; | 156 | struct list_head list; |
161 | }; | 157 | }; |
162 | 158 | ||
159 | /* | ||
160 | * Target features | ||
161 | */ | ||
162 | |||
163 | /* | ||
164 | * Any table that contains an instance of this target must have only one. | ||
165 | */ | ||
166 | #define DM_TARGET_SINGLETON 0x00000001 | ||
167 | #define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON) | ||
168 | |||
163 | struct dm_target { | 169 | struct dm_target { |
164 | struct dm_table *table; | 170 | struct dm_table *table; |
165 | struct target_type *type; | 171 | struct target_type *type; |