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path: root/drivers/md/dm-log-userspace-base.c
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2009-09-10md: Fix "strchr" [drivers/md/dm-log-userspace.ko] undefined!Geert Uytterhoeven
Commit b8313b6da7e2e7c7f47d93d8561969a3ff9ba0ea ("dm log: remove incorrect field from userspace table output") added a call to strstr() with a single-character "needle" string parameter. Unfortunately some versions of gcc replace such calls to strstr() by calls to strchr() behind our back. This causes linking errors if strchr() is defined as an inline function in <asm/string.h> (e.g. on m68k): | WARNING: "strchr" [drivers/md/dm-log-userspace.ko] undefined! Avoid this by explicitly calling strchr() instead. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-04dm log: userspace add luid to distinguish between concurrent log instancesJonathan Brassow
Device-mapper userspace logs (like the clustered log) are identified by a universally unique identifier (UUID). This identifier is used to associate requests from the kernel to a specific log in userspace. The UUID must be unique everywhere, since multiple machines may use this identifier when communicating about a particular log, as is the case for cluster logs. Sometimes, device-mapper/LVM may re-use a UUID. This is the case during pvmoves, when moving from one segment of an LV to another, or when resizing a mirror, etc. In these cases, a new log is created with the same UUID and loaded in the "inactive" slot. When a device-mapper "resume" is issued, the "live" table is deactivated and the new "inactive" table becomes "live". (The "inactive" table can also be removed via a device-mapper 'clear' command.) The above two issues were colliding. More than one log was being created with the same UUID, and there was no way to distinguish between them. So, sometimes the wrong log would be swapped out during the exchange. The solution is to create a locally unique identifier, 'luid', to go along with the UUID. This new identifier is used to determine exactly which log is being referenced by the kernel when the log exchange is made. The identifier is not universally safe, but it does not need to be, since create/destroy/suspend/resume operations are bound to a specific machine; and these are the operations that make up the exchange. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-09-04dm log: remove incorrect field from userspace table outputJonathan Brassow
The output of 'dmsetup table' includes an internal field that should not be there. This patch removes it. To make the fix simpler, we first reorder a constructor argument The 'device size' argument is generated internally. Currently it is placed as the last space-separated word of the constructor string. However, we need to use a version of the string without this word, so we move it to the beginning instead so it is trivial to skip past it. We keep a copy of the arguments passed to userspace for creating a log, just in case we need to resend them. These are the same arguments that are desired in the STATUSTYPE_TABLE request, except for one. When creating the userspace log, the userspace daemon must know the size of the mirror, so that is added to the arguments given in the constructor table. We were printing this extra argument out as well, which is a mistake. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-09-04dm log: fix userspace status outputJonathan Brassow
Fix 'dmsetup table' output. There is a missing ' ' at the end of the string causing two words to run together. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm raid1: add userspace logJonthan Brassow
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 <jbrassow@redhat.com> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Alasdair G Kergon <agk@redhat.com>