path: root/include/linux/dm-log-userspace.h
diff options
authorLinus Torvalds <torvalds@linux-foundation.org>2009-09-05 13:51:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-05 13:51:07 -0700
commit154f807e55977de75b1c12197c13ae14c28397b3 (patch)
tree5ff5a220e4d3080275ce4921e28ef02f374ed5f7 /include/linux/dm-log-userspace.h
parent9b6a3df372f0318bb0ffe37ac5f4610fb9bdb44d (diff)
parentae0b7448e91353ea5f821601a055aca6b58042cd (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm
* git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm: dm snapshot: fix on disk chunk size validation dm exception store: split set_chunk_size dm snapshot: fix header corruption race on invalidation dm snapshot: refactor zero_disk_area to use chunk_io dm log: userspace add luid to distinguish between concurrent log instances dm raid1: do not allow log_failure variable to unset after being set dm log: remove incorrect field from userspace table output dm log: fix userspace status output dm stripe: expose correct io hints dm table: add more context to terse warning messages dm table: fix queue_limit checking device iterator dm snapshot: implement iterate devices dm multipath: fix oops when request based io fails when no paths
Diffstat (limited to 'include/linux/dm-log-userspace.h')
1 files changed, 12 insertions, 1 deletions
diff --git a/include/linux/dm-log-userspace.h b/include/linux/dm-log-userspace.h
index 642e3017b51f..8a1f972c0fe9 100644
--- a/include/linux/dm-log-userspace.h
+++ b/include/linux/dm-log-userspace.h
@@ -371,7 +371,18 @@
(DM_ULOG_REQUEST_MASK & (request_type))
struct dm_ulog_request {
- char uuid[DM_UUID_LEN]; /* Ties a request to a specific mirror log */
+ /*
+ * The local unique identifier (luid) and the universally unique
+ * identifier (uuid) are used to tie a request to a specific
+ * mirror log. A single machine log could probably make due with
+ * just the 'luid', but a cluster-aware log must use the 'uuid' and
+ * the 'luid'. The uuid is what is required for node to node
+ * communication concerning a particular log, but the 'luid' helps
+ * differentiate between logs that are being swapped and have the
+ * same 'uuid'. (Think "live" and "inactive" device-mapper tables.)
+ */
+ uint64_t luid;
+ char uuid[DM_UUID_LEN];
char padding[7]; /* Padding because DM_UUID_LEN = 129 */
int32_t error; /* Used to report back processing errors */