From 36a0456fbf2d9680bf9af81b39daf4a8e22cb1b8 Mon Sep 17 00:00:00 2001 From: Alasdair G Kergon Date: Mon, 31 Oct 2011 20:19:04 +0000 Subject: 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 --- include/linux/device-mapper.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux/device-mapper.h') 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; -- cgit v1.2.3