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authorAlasdair G Kergon <agk@redhat.com>2011-11-01 00:19:04 +0400
committerAlasdair G Kergon <agk@redhat.com>2011-11-01 00:19:04 +0400
commit36a0456fbf2d9680bf9af81b39daf4a8e22cb1b8 (patch)
treea19af18640d538e8357c195e6b4c77d0f6c92391 /include/linux/device-mapper.h
parentcc6cbe141a20f6d876b161b60af38d93935bfa85 (diff)
downloadlinux-36a0456fbf2d9680bf9af81b39daf4a8e22cb1b8.tar.xz
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 'include/linux/device-mapper.h')
-rw-r--r--include/linux/device-mapper.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index cc58e2d7c032..98f34b886f95 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -173,6 +173,13 @@ struct target_type {
#define dm_target_always_writeable(type) \
((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
+/*
+ * Any device that contains a table with an instance of this target may never
+ * have tables containing any different target type.
+ */
+#define DM_TARGET_IMMUTABLE 0x00000004
+#define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
+
struct dm_target {
struct dm_table *table;
struct target_type *type;