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* dm thin: commit before gathering statusAlasdair G Kergon2012-07-271-1/+1
| | | | | | | | | | | | | | | | Commit outstanding metadata before returning the status for a dm thin pool so that the numbers reported are as up-to-date as possible. The commit is not performed if the device is suspended or if the DM_NOFLUSH_FLAG is supplied by userspace and passed to the target through a new 'status_flags' parameter in the target's dm_status_fn. The userspace dmsetup tool will support the --noflush flag with the 'dmsetup status' and 'dmsetup wait' commands from version 1.02.76 onwards. Tested-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: add retain_attached_hw_handler featureMike Snitzer2012-07-271-6/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A SCSI device handler might get attached to a device during the initial device scan. We do not necessarily want to override this when loading a multipath table, so this patch adds a new multipath feature argument "retain_attached_hw_handler". During SCSI device scan all loaded SCSI device handlers will be consulted for a match (via scsi_dh's provided .match). If a match is found that device handler will be attached. We need a way to have userspace multipathd's provided 'hw_handler' not override the already attached hardware handler. When specifying the new feature 'retain_attached_hw_handler' multipath will use the currently attached hardware handler instead of trying to attach the one specified during table load. If no hardware handler is attached the specified hardware handler will still be used. Leverages scsi_dh_attach's ability to increment the scsi_dh's reference count if the same scsi_dh name is provided when attaching - currently attached scsi_dh name is determined with scsi_dh_attached_handler_name. Depends upon commit 7e8a74b177f17d100916b6ad415450f7c9508691 ("[SCSI] scsi_dh: add scsi_dh_attached_handler_name"). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Tested-by: Babu Moger <babu.moger@netapp.com> Reviewed-by: Chandra Seetharaman <sekharan@us.ibm.com> Acked-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: allow ioctls to trigger pg initMikulas Patocka2012-06-031-9/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | After the failure of a group of paths, any alternative paths that need initialising do not become available until further I/O is sent to the device. Until this has happened, ioctls return -EAGAIN. With this patch, new paths are made available in response to an ioctl too. The processing of the ioctl gets delayed until this has happened. Instead of returning an error, we submit a work item to kmultipathd (that will potentially activate the new path) and retry in ten milliseconds. Note that the patch doesn't retry an ioctl if the ioctl itself fails due to a path failure. Such retries should be handled intelligently by the code that generated the ioctl in the first place, noting that some SCSI commands should not be retried because they are not idempotent (XOR write commands). For commands that could be retried, there is a danger that if the device rejected the SCSI command, the path could be errorneously marked as failed, and the request would be retried on another path which might fail too. It can be determined if the failure happens on the device or on the SCSI controller, but there is no guarantee that all SCSI drivers set these flags correctly. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: delay retry of bypassed pgMike Christie2012-06-031-2/+6
| | | | | | | | | | | | | | If I/O needs retrying and only bypassed priority groups are available, set the pg_init_delay_retry flag to wait before retrying. If, for example, the reason for the bypass is that the controller is getting reset or there is a firmware upgrade happening, retrying right away would cause a flood of log messages and retries for what could be a few seconds or even several minutes. Signed-off-by: Mike Christie <michaelc@cs.wisc.edu> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: reduce size of struct multipathMike Snitzer2012-06-031-6/+7
| | | | | | | | | | | Move multipath structure's 'lock' and 'queue_size' members to eliminate two 4-byte holes. Also use a bit within a single unsigned int for each existing flag (saves 8-bytes). This allows future flags to be added without each consuming an unsigned int. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: check if scsi_dh module already loaded before trying to loadMike Snitzer2012-05-121-2/+2
| | | | | | | | | | | | If the requested scsi_dh module is already loaded then skip request_module(). Multipath table loads can hang in an unnecessary __request_module. Reported-by: Ben Marzinski <bmarzins@redhat.com> Cc: stable@kernel.org Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: reject trailing characters in sccanf inputMikulas Patocka2012-03-281-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | Device mapper uses sscanf to convert arguments to numbers. The problem is that the way we use it ignores additional unmatched characters in the scanned string. For example, this `if (sscanf(string, "%d", &number) == 1)' will match a number, but also it will match number with some garbage appended, like "123abc". As a result, device mapper accepts garbage after some numbers. For example the command `dmsetup create vg1-new --table "0 16384 linear 254:1bla 34816bla"' will pass without an error. This patch fixes all sscanf uses in device mapper. It appends "%c" with a pointer to a dummy character variable to every sscanf statement. The construct `if (sscanf(string, "%d%c", &number, &dummy) == 1)' succeeds only if string is a null-terminated number (optionally preceded by some whitespace characters). If there is some character appended after the number, sscanf matches "%c", writes the character to the dummy variable and returns 2. We check the return value for 1 and consequently reject numbers with some garbage appended. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: detect invalid map_contextJun'ichi Nomura2012-03-281-14/+32
| | | | | | | | | | | | | The map_context pointer should always be set. However, we have reports that upon requeuing it is not set correctly. So add set and clear functions with a BUG_ON() to track the issue properly. Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: Mike Snitzer <snitzer@redhat.com> Acked-by: Hannes Reinecke <hare@suse.de> Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Dave Wysochanski <dwysocha@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: do not forward ioctls from logical volumes to the underlying devicePaolo Bonzini2012-01-151-0/+6
| | | | | | | | | | | | A logical volume can map to just part of underlying physical volume. In this case, it must be treated like a partition. Based on a patch from Alasdair G Kergon. Cc: Alasdair G Kergon <agk@redhat.com> Cc: dm-devel@redhat.com Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* dm table: share target argument parsing functionsMike Snitzer2011-08-021-108/+44
| | | | | | | | Move multipath target argument parsing code into dm-table so other targets can share it. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: fix potential NULL pointer in feature arg processingMike Snitzer2011-08-021-0/+5
| | | | | | | | | Avoid dereferencing a NULL pointer if the number of feature arguments supplied is fewer than indicated. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@kernel.org
* atomic: use <linux/atomic.h>Arun Sharma2011-07-271-1/+1
| | | | | | | | | | | | | | This allows us to move duplicated code in <asm/atomic.h> (atomic_inc_not_zero() for now) to <linux/atomic.h> Signed-off-by: Arun Sharma <asharma@fb.com> Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* dm mpath: do not fail paths after integrity errorsMartin K. Petersen2011-05-291-1/+1
| | | | | | | | | | | Integrity errors need to be passed to the owner of the integrity metadata for processing. Consequently EILSEQ should be passed up the stack. Cc: stable@kernel.org Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: allow table load with no priority groupsMike Snitzer2011-03-241-3/+10
| | | | | | | | | | | | | | | | | | | | | | | | This patch adjusts the multipath target to allow a table with both 0 priority groups and 0 for the initial priority group number. If any mpath device is held open when all paths in the last priority group have failed, userspace multipathd will attempt to reload the associated DM table to reflect the fact that the device no longer has any priority groups. But the reload attempt always failed because the multipath target did not allow 0 priority groups. All multipath target messages related to priority group (enable_group, disable_group, switch_group) will handle a priority group of 0 (will cause error). When reloading a multipath table with 0 priority groups, userspace multipathd must be updated to specify an initial priority group number of 0 (rather than 1). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: Babu Moger <babu.moger@lsi.com> Acked-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: fail message ioctl if specified path is not validMike Snitzer2011-03-241-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | Fail the reinstate_path and fail_path message ioctl if the specified path is not valid. The message ioctl would succeed for the 'reinistate_path' and 'fail_path' messages even if action was not taken because the specified device was not a valid path of the multipath device. Before, when /dev/vdb is not a path of mpathb: $ dmsetup message mpathb 0 reinstate_path /dev/vdb $ echo $? 0 After: $ dmsetup message mpathb 0 reinstate_path /dev/vdb device-mapper: message ioctl failed: Invalid argument Command failed $ echo $? 1 Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* [SCSI] dm mpath: propagate target errors immediatelyHannes Reinecke2011-02-121-12/+10
| | | | | | | | | | | | | | | | DM now has more information about the nature of the underlying storage failure. Path failure is avoided if a request failed due to a target error. Instead the target error is immediately passed up the stack. Discard requests that fail due to non-target errors may now be retried. Errors restricted to the path will be retried or returned if no paths are available, irregarding the no_path_retry setting. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Hannes Reinecke <hare@suse.de> Acked-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
* dm mpath: delay activate_path retry on SCSI_DH_RETRYChandra Seetharaman2011-01-131-10/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds a user-configurable 'pg_init_delay_msecs' feature. Use this feature to specify the number of milliseconds to delay before retrying scsi_dh_activate, when SCSI_DH_RETRY is returned. SCSI Device Handlers return SCSI_DH_IMM_RETRY if we could retry activation immediately and SCSI_DH_RETRY in cases where it is better to retry after some delay. Currently we immediately retry scsi_dh_activate irrespective of SCSI_DH_IMM_RETRY and SCSI_DH_RETRY. The 'pg_init_delay_msecs' feature may be provided during table create or load, e.g.: dmsetup create --table "0 20971520 multipath 3 queue_if_no_path \ pg_init_delay_msecs 2500 ..." mpatha The default for 'pg_init_delay_msecs' is 2000 milliseconds. Maximum configurable delay is 60000 milliseconds. Specifying a 'pg_init_delay_msecs' of 0 will cause immediate retry. Signed-off-by: Nikanth Karthikesan <knikanth@suse.de> Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Acked-by: Mike Christie <michaelc@cs.wisc.edu> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: convert workqueues to alloc_orderedTejun Heo2011-01-131-2/+3
| | | | | | | | | | Convert all create[_singlethread]_work() users to the new alloc[_ordered]_workqueue(). This conversion is mechanical and doesn't introduce any behavior change. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: dont use flush_scheduled_workTejun Heo2011-01-131-1/+1
| | | | | | | | | | flush_scheduled_work() is being deprecated. Flush the used work directly instead. In all dm targets, the only work which uses system_wq is ->trigger_event. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: disable blk_abort_queueMike Snitzer2011-01-131-12/+0
| | | | | | | | | | | | | | | | | | | | | Revert commit 224cb3e981f1b2f9f93dbd49eaef505d17d894c2 dm: Call blk_abort_queue on failed paths Multipath began to use blk_abort_queue() to allow for lower latency path deactivation. This was found to cause list corruption: the cmd gets blk_abort_queued/timedout run on it and the scsi eh somehow is able to complete and run scsi_queue_insert while scsi_request_fn is still trying to process the request. https://www.redhat.com/archives/dm-devel/2010-November/msg00085.html Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: Mike Anderson <andmike@linux.vnet.ibm.com> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: stable@kernel.org
* dm mpath: support discardMike Snitzer2010-08-121-0/+10
| | | | | | | | | | | | | | | | | | Enable discard support in the DM multipath target. This discard support depends on a few discard-specific fixes to the block layer's request stacking driver methods. Discard requests are optional so don't allow a failed discard to trigger path failures. If there is a real problem with a given path the barriers associated with the discard (either before or after the discard) will cause path failure. That said, unconditionally passing discard failures up the stack is not ideal. This must be fixed once DM has more information about the nature of the underlying storage failure. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
* dm mpath: fix NULL pointer dereference when path parameters missingAlasdair G Kergon2010-08-121-0/+1
| | | | | | | | | multipath_ctr() forgets to return an error after detecting missing path parameters. Fix this. Signed-off-by: Patrick LoPresti <lopresti@gmail.com> Cc: stable@kernel.org Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm table: remove unused dm_get_device range parametersNikanth Karthikesan2010-03-061-4/+3
| | | | | | | | Remove unused parameters(start and len) of dm_get_device() and fix the callers. Signed-off-by: Nikanth Karthikesan <knikanth@suse.de> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: refactor pg_initKiyoshi Ueda2010-03-061-12/+19
| | | | | | | | | | | This patch pulls the pg_init path activation code out of process_queued_ios() into a new function. No functional change. Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: wait for pg_init completion when suspendingKiyoshi Ueda2010-03-061-3/+35
| | | | | | | | | | | | | When suspending the device we must wait for all I/O to complete, but pg-init may be still in progress even after flushing the workqueue for kmpath_handlerd in multipath_postsuspend. This patch waits for pg-init completion correctly in multipath_postsuspend(). Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: hold io until all pg_inits completedKiyoshi Ueda2010-03-061-6/+11
| | | | | | | | | | | | | | | | | | m->queue_io is set to block processing I/Os, and it needs to be kept while pg-init, which issues multiple path activations, is in progress. But m->queue is cleared when a path activation completes without error in pg_init_done(), even while other path activations are in progress. That may cause undesired -EIO on paths which are not complete activation. This patch fixes that by not clearing m->queue_io until all path activations complete. (Before the hardware handlers were moved into the SCSI layer, pg_init only used one path.) Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: avoid storing private suspended stateKiyoshi Ueda2010-03-061-12/+0
| | | | | | | | | | | 'suspended' flag in struct multipath was introduced to check whether the multipath target is in suspended state, but the same check is done through dm_suspended() now, so remove the flag and related code. Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: Mike Anderson <andmike@linux.vnet.ibm.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: skip activate_path for failed pathsMoger, Babu2010-03-061-2/+5
| | | | | | | | | | | | | This patch adds two minor fixes while processing device mapper path activation. Skip failed paths while calling activate_path. If the path is already failed then activate_path will fail for sure. We don't have to call in that case. In some case this might cause prolonged retries unnecessarily. Change the misleading message if the path being activated fails with SCSI_DH_NOSYS. Signed-off-by: Babu Moger <babu.moger@lsi.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: pass struct pgpath to pg init doneMoger, Babu2010-03-061-3/+2
| | | | | | | | | | | | | | | This patch removes some unnecessary argument casting. There is no functional change with this patch. Passes 'struct pgpath' through to pg_init_done() instead of the enclosed 'struct dm_path'. Tested the changes with LSI storage.. CC: Chandra Seetharaman <chandra.seetharaman@us.ibm.com> Signed-off-by: Babu Moger <babu.moger@lsi.com> Acked-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: reject messages when device is suspendedKiyoshi Ueda2009-12-111-0/+5
| | | | | | | | | | This patch rejects messages that can generate I/O while the device itself is suspended. Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Cc: Mike Anderson <andmike@linux.vnet.ibm.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: prevent io from work queue while suspendedMike Anderson2009-12-111-0/+12
| | | | | | | | | Reject messages that can generate I/O while the device itself is suspended. Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com> Acked-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: add mutex to synchronize adding and flushing workMike Anderson2009-12-111-21/+38
| | | | | | | | | Add a mutex to allow possible creators of new work to synchronize with flushing work queues. Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com> Acked-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: flush workqueues before suspend completesKiyoshi Ueda2009-12-111-4/+15
| | | | | | | | | | | | | | This patch stops the remaining dm-mpath activity during the suspend sequence by flushing workqueues in postsuspend function. The current dm-mpath target may not be quiet even after suspend completes because some workqueues (e.g. device_handler's work, event handling) are not flushed during the suspend sequence, even though suspended devices/targets are supposed to be quiet in this state. Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* [SCSI] scsi_dh: Change the scsidh_activate interface to be asynchronousChandra Seetharaman2009-12-041-4/+4
| | | | | | | | | Make scsi_dh_activate() function asynchronous, by taking in two additional parameters, one is the callback function and the other is the data to call the callback function with. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
* [SCSI] scsi_dh: Use scsi_dh_set_params() in multipath.Chandra Seetharaman2009-08-231-6/+36
| | | | | | | | | | | | Use scsi_dh_set_params() set parameters provided. Save the parameters in parse_hw_handler() and use it in parse_path(). Reported-by: Eddie Williams <Eddie.Williams@steeleye.com> Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Tested-by: Eddie Williams <Eddie.Williams@steeleye.com> Cc: Alasdair G Kergon <agk@redhat.com> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
* dm table: pass correct dev area size to device_area_is_validMike Snitzer2009-07-231-1/+1
| | | | | | | | | | | | | | | | Incorrect device area lengths are being passed to device_area_is_valid(). The regression appeared in 2.6.31-rc1 through commit 754c5fc7ebb417b23601a6222a6005cc2e7f2913. With the dm-stripe target, the size of the target (ti->len) was used instead of the stripe_width (ti->len/#stripes). An example of a consequent incorrect error message is: device-mapper: table: 254:0: sdb too small for target Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: change to be request basedKiyoshi Ueda2009-06-221-65/+128
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch converts dm-multipath target to request-based from bio-based. Basically, the patch just converts the I/O unit from struct bio to struct request. In the course of the conversion, it also changes the I/O queueing mechanism. The change in the I/O queueing is described in details as follows. I/O queueing mechanism change ----------------------------- In I/O submission, map_io(), there is no mechanism change from bio-based, since the clone request is ready for retry as it is. However, in I/O complition, do_end_io(), there is a mechanism change from bio-based, since the clone request is not ready for retry. In do_end_io() of bio-based, the clone bio has all needed memory for resubmission. So the target driver can queue it and resubmit it later without memory allocations. The mechanism has almost no overhead. On the other hand, in do_end_io() of request-based, the clone request doesn't have clone bios, so the target driver can't resubmit it as it is. To resubmit the clone request, memory allocation for clone bios is needed, and it takes some overheads. To avoid the overheads just for queueing, the target driver doesn't queue the clone request inside itself. Instead, the target driver asks dm core for queueing and remapping the original request of the clone request, since the overhead for queueing is just a freeing memory for the clone request. As a result, the target driver doesn't need to record/restore the information of the original request for resubmitting the clone request. So dm_bio_details in dm_mpath_io is removed. multipath_busy() --------------------- The target driver returns "busy", only when the following case: o The target driver will map I/Os, if map() function is called and o The mapped I/Os will wait on underlying device's queue due to their congestions, if map() function is called now. In other cases, the target driver doesn't return "busy". Otherwise, dm core will keep the I/Os and the target driver can't do what it wants. (e.g. the target driver can't map I/Os now, so wants to kill I/Os.) Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Acked-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm target:s introduce iterate devices fnMike Snitzer2009-06-221-1/+22
| | | | | | | | | | | | | | Add .iterate_devices to 'struct target_type' to allow a function to be called for all devices in a DM target. Implemented it for all targets except those in dm-snap.c (origin and snapshot). (The raid1 version number jumps to 1.12 because we originally reserved 1.1 to 1.11 for 'block_on_error' but ended up using 'handle_errors' instead.) Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: martin.petersen@oracle.com
* dm mpath: add start_io and nr_bytes to path selectorsKiyoshi Ueda2009-06-221-10/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | This patch makes two additions to the dm path selector interface for dynamic load balancers: o a new hook, start_io() o a new parameter 'nr_bytes' to select_path()/start_io()/end_io() to pass the size of the I/O start_io() is called when a target driver actually submits I/O to the selected path. Path selectors can use it to start accounting of the I/O. (e.g. counting the number of in-flight I/Os.) The start_io hook is based on the patch posted by Stefan Bader: https://www.redhat.com/archives/dm-devel/2005-October/msg00050.html nr_bytes, the size of the I/O, is so path selectors can take the size of the I/O into account when deciding which path to use. dm-service-time uses it to estimate service time, for example. (Added the nr_bytes member to dm_mpath_io instead of using existing details.bi_size, since request-based dm patch deletes it.) Signed-off-by: Stefan Bader <stefan.bader@canonical.com> Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: support barriersMikulas Patocka2009-06-221-0/+2
| | | | | | | Flush support for dm-multipath target. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: flush keventd queue in destructorMikulas Patocka2009-06-221-0/+1
| | | | | | | | | | | | | | | | | | | | | The commit fe9cf30eb8186ef267d1868dc9f12f2d0f40835a moves dm table event submission from kmultipath queue to kernel kevent queue to avoid a deadlock. There is a possibility of race condition because kevent queue is not flushed in the multipath destructor. The scenario is: - some event happens and is queued to keventd - keventd thread is delayed due to scheuling latency or some other work - multipath device is destroyed - keventd now attempts to process work_struct that is residing in already released memory. The patch flushes the keventd queue in multipath constructor. I've already fixed similar bug in dm-raid1. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@kernel.org
* dm mpath: call activate fn for each path in pg_initChandra Seetharaman2009-06-221-37/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fixed a problem affecting reinstatement of passive paths. Before we moved the hardware handler from dm to SCSI, it performed a pg_init for a path group and didn't maintain any state about each path in hardware handler code. But in SCSI dh, such state is now maintained, as we want to fail I/O early on a path if it is not the active path. All the hardware handlers have a state now and set to active or some form of inactive. They have prep_fn() which uses this state to fail the I/O without it ever being sent to the device. So in effect when dm-multipath calls scsi_dh_activate(), activate is sent to only one path and the "state" of that path is changed appropriately to "active" while other paths in the same path group are never changed as they never got an "activate". In order make sure all the paths in a path group gets their state set properly when a pg_init happens, we need to call scsi_dh_activate() on all paths in a path group. Doing this at the hardware handler layer is not a good option as we want the multipath layer to define the relationship between path and path groups and not the hardware handler. Attached patch sends an "activate" on each path in a path group when a path group is switched. It also sends an activate when a path is reinstated. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: change attached scsi_dhHannes Reinecke2009-06-221-2/+13
| | | | | | | | | | | | | | | | | | | | When specifying a different hardware handler via multipath features we should be able to override the built-in defaults. The problem here is the hardware table from scsi_dh is compiled in and cannot be changed from userland. The multipath.conf OTOH is purely user-defined and, what's more, the user might have a valid reason for modifying it. (EG EMC Clariion can well be run in PNR mode even though ALUA is active, or the user might want to try ALUA on any as-of-yet unknown devices) So _not_ allowing multipath to override the device handler setting will just add to the confusion and makes error tracking even more difficult. Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: validate hw_handler argument countMikulas Patocka2009-06-221-0/+5
| | | | | | | | Fix arg count parsing error in hw handlers. Cc: stable@kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: validate table argument countMikulas Patocka2009-06-221-0/+6
| | | | | | | | | | | | | | The parser reads the argument count as a number but doesn't check that sufficient arguments are supplied. This command triggers the bug: dmsetup create mpath --table "0 `blockdev --getsize /dev/mapper/cr0` multipath 0 0 2 1 round-robin 1000 0 1 1 /dev/mapper/cr0 round-robin 0 1 1 /dev/mapper/cr1 1000" kernel BUG at drivers/md/dm-mpath.c:530! Cc: stable@kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* block: move bio list helpers into bio.hChristoph Hellwig2009-04-151-1/+0
| | | | | | | | | It's used by DM and MD and generally useful, so move the bio list helpers into bio.h. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* dm mpath: move trigger_event to system workqueueAlasdair G Kergon2009-01-061-4/+4
| | | | | | | | | The same workqueue is used both for sending uevents and processing queued I/O. Deadlock has been reported in RHEL5 when sending a uevent was blocked waiting for the queued I/O to be processed. Use scheduled_work() for the asynchronous uevents instead. Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: consolidate target deregistration error handlingMikulas Patocka2009-01-061-5/+1
| | | | | | | | | | | | | | | | | | | | Change dm_unregister_target to return void and use BUG() for error reporting. dm_unregister_target can only fail because of programming bug in the target driver. It can't fail because of user's behavior or disk errors. This patch changes unregister_target to return void and use BUG if someone tries to unregister non-registered target or unregister target that is in use. This patch removes code duplication (testing of error codes in all dm targets) and reports bugs in just one place, in dm_unregister_target. In some target drivers, these return codes were ignored, which could lead to a situation where bugs could be missed. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: warn if args ignoredChandra Seetharaman2008-11-141-0/+4
| | | | | | | | | | | Currently dm ignores the parameters provided to hardware handlers without providing any notifications to the user. This patch just prints a warning message so that the user knows that the arguments are ignored. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: avoid attempting to activate null pathChandra Seetharaman2008-11-141-2/+2
| | | | | | | | | | | Path activation code is called even when the pgpath is NULL. This could lead to a panic in activate_path(). Such a panic is seen in -rt kernel. This problem has been there before the pg_init() was moved to a workqueue. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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