From f5db4af466e2dca0fe822019812d586ca910b00c Mon Sep 17 00:00:00 2001 From: Jonthan Brassow Date: Mon, 22 Jun 2009 10:12:35 +0100 Subject: dm raid1: add userspace log This patch contains a device-mapper mirror log module that forwards requests to userspace for processing. The structures used for communication between kernel and userspace are located in include/linux/dm-log-userspace.h. Due to the frequency, diversity, and 2-way communication nature of the exchanges between kernel and userspace, 'connector' was chosen as the interface for communication. The first log implementations written in userspace - "clustered-disk" and "clustered-core" - support clustered shared storage. A userspace daemon (in the LVM2 source code repository) uses openAIS/corosync to process requests in an ordered fashion with the rest of the nodes in the cluster so as to prevent log state corruption. Other implementations with no association to LVM or openAIS/corosync, are certainly possible. (Imagine if two machines are writing to the same region of a mirror. They would both mark the region dirty, but you need a cluster-aware entity that can handle properly marking the region clean when they are done. Otherwise, you might clear the region when the first machine is done, not the second.) Signed-off-by: Jonathan Brassow Cc: Evgeniy Polyakov Signed-off-by: Alasdair G Kergon --- drivers/md/Kconfig | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'drivers/md/Kconfig') diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig index 09f93fa68912..020f9573fd82 100644 --- a/drivers/md/Kconfig +++ b/drivers/md/Kconfig @@ -231,6 +231,17 @@ config DM_MIRROR Allow volume managers to mirror logical volumes, also needed for live data migration tools such as 'pvmove'. +config DM_LOG_USERSPACE + tristate "Mirror userspace logging (EXPERIMENTAL)" + depends on DM_MIRROR && EXPERIMENTAL && NET + select CONNECTOR + ---help--- + The userspace logging module provides a mechanism for + relaying the dm-dirty-log API to userspace. Log designs + which are more suited to userspace implementation (e.g. + shared storage logs) or experimental logs can be implemented + by leveraging this framework. + config DM_ZERO tristate "Zero target" depends on BLK_DEV_DM -- cgit v1.2.1