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path: root/drivers/md/dm-log-userspace-transfer.c
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* dm log: userspace fix overhead_size calcuationsJonathan Brassow2010-02-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes two bugs that revolve around the miscalculation and misuse of the variable 'overhead_size'. 'overhead_size' is the size of the various header structures used during communication. The first bug is the use of 'sizeof' with the pointer of a structure instead of the structure itself - resulting in the wrong size being computed. This is then used in a check to see if the payload (data_size) would be to large for the preallocated structure. Since the bug produces a smaller value for the overhead, it was possible for the structure to be breached. (Although the current users of the code do not currently send enough data to trigger this bug.) The second bug is that the 'overhead_size' value is used to compute how much of the preallocated space should be cleared before populating it with fresh data. This should have simply been 'sizeof(struct cn_msg)' not overhead_size. The fact that 'overhead_size' was computed incorrectly made this problem "less bad" - leaving only a pointer's worth of space at the end uncleared. Thus, this bug was never producing a bad result, but still needs to be fixed - especially now that the value is computed correctly. Cc: stable@kernel.org Signed-off-by: Jonathan Brassow <jbrassow@redhat.com Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm/connector: Only process connector packages from privileged processesPhilipp Reisner2009-10-02
| | | | | Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* connector/dm: Fixed a compilation warningPhilipp Reisner2009-10-02
| | | | | | | Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Acked-by: Lars Ellenberg <lars.ellenberg@linbit.com> Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* connector: Provide the sender's credentials to the callbackPhilipp Reisner2009-10-02
| | | | | | | Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Acked-by: Lars Ellenberg <lars.ellenberg@linbit.com> Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* dm log: userspace add luid to distinguish between concurrent log instancesJonathan Brassow2009-09-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* dm-log-userspace: fix printk format warningRandy Dunlap2009-08-16
| | | | | | | | | | | drivers/md/dm-log-userspace-transfer.c:110: warning: format '%lu' expects type 'long unsigned int', but argument 4 has type 'size_t' Previously posted and acked, but apparently lost. http://lkml.indiana.edu/hypermail/linux/kernel/0906.2/02074.html Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: dm-devel@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* dm raid1: add userspace logJonthan Brassow2009-06-22
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>