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path: root/drivers/md
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2009-07-10Fix congestion_wait() sync/async vs read/write confusionJens Axboe
Commit 1faa16d22877f4839bd433547d770c676d1d964c accidentally broke the bdi congestion wait queue logic, causing us to wait on congestion for WRITE (== 1) when we really wanted BLK_RW_ASYNC (== 0) instead. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-08Remove multiple KERN_ prefixes from printk formatsJoe Perches
Commit 5fd29d6ccbc98884569d6f3105aeca70858b3e0f ("printk: clean up handling of log-levels and newlines") changed printk semantics. printk lines with multiple KERN_<level> prefixes are no longer emitted as before the patch. <level> is now included in the output on each additional use. Remove all uses of multiple KERN_<level>s in formats. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-01Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds
* 'for-linus' of git://git.kernel.dk/linux-2.6-block: cfq-iosched: remove redundant check for NULL cfqq in cfq_set_request() blocK: Restore barrier support for md and probably other virtual devices. block: get rid of queue-private command filter block: Create bip slabs with embedded integrity vectors cfq-iosched: get rid of the need for __GFP_NOFAIL in cfq_find_alloc_queue() cfq-iosched: move cfqq initialization out of cfq_find_alloc_queue() Trivial typo fixes in Documentation/block/data-integrity.txt.
2009-07-01Merge branch 'for-linus' of git://neil.brown.name/mdLinus Torvalds
* 'for-linus' of git://neil.brown.name/md: md: use interruptible wait when duration is controlled by userspace. md/raid5: suspend shouldn't affect read requests. md: tidy up error paths in md_alloc md: fix error path when duplicate name is found on md device creation. md: avoid dereferencing NULL pointer when accessing suspend_* sysfs attributes. md: Use new topology calls to indicate alignment and I/O sizes
2009-07-01block: Create bip slabs with embedded integrity vectorsMartin K. Petersen
This patch restores stacking ability to the block layer integrity infrastructure by creating a set of dedicated bip slabs. Each bip slab has an embedded bio_vec array at the end. This cuts down on memory allocations and also simplifies the code compared to the original bvec version. Only the largest bip slab is backed by a mempool. The pool is contained in the bio_set so stacking drivers can ensure forward progress. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@carl.(none)>
2009-07-01md: use interruptible wait when duration is controlled by userspace.NeilBrown
User space can set various limits on an md array so that resync waits when it gets to a certain point, or so that I/O is blocked for a short while. When md is waiting against one of these limit, it should use an interruptible wait so as not to add to the load average, and so are not to trigger a warning if the wait goes on for too long. Signed-off-by: NeilBrown <neilb@suse.de>
2009-07-01md/raid5: suspend shouldn't affect read requests.NeilBrown
md allows write to regions on an array to be suspended temporarily. This allows user-space to participate is aspects of reshape. In particular, data can be copied with not risk of a race. We should not be blocking read requests though, so don't. Cc: stable@kernel.org Signed-off-by: NeilBrown <neilb@suse.de>
2009-07-01md: tidy up error paths in md_allocNeilBrown
As the recent bug in md_alloc showed, having a single exit path for unlocking and putting is a good idea. So restructure md_alloc to have a single mutex_unlock and mddev_put, and use gotos where necessary. Found-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: NeilBrown <neilb@suse.de>
2009-07-01md: fix error path when duplicate name is found on md device creation.NeilBrown
When an md device is created by name (rather than number) we need to check that the name is not already in use. If this check finds a duplicate, we return an error without dropping the lock or freeing the newly create mddev. This patch fixes that. Cc: stable@kernel.org Found-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: NeilBrown <neilb@suse.de>
2009-07-01md: avoid dereferencing NULL pointer when accessing suspend_* sysfs attributes.NeilBrown
If we try to modify one of the md/ sysfs files suspend_lo or suspend_hi when the array is not active, we dereference a NULL. Protect against that. Cc: stable@kernel.org Signed-off-by: NeilBrown <neilb@suse.de>
2009-07-01md: Use new topology calls to indicate alignment and I/O sizesMartin K. Petersen
Switch MD over to the new disk_stack_limits() function which checks for aligment and adjusts preferred I/O sizes when stacking. Also indicate preferred I/O sizes where applicable. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: NeilBrown <neilb@suse.de>
2009-06-30dm table: fix blk_stack_limits arg to use bytes not sectorsMike Snitzer
The offset passed to blk_stack_limits() must be in bytes not sectors. Fixes false warnings like the following: device-mapper: table: 254:1: target device sda6 is misaligned Signed-off-by: Mike Snitzer <snitzer@redhat.com> Reported-by: Frans Pop <elendil@planet.nl> Tested-by: Frans Pop <elendil@planet.nl> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-30dm exception store: really fix type lookupMilan Broz
Fix exception store name handling. We need to reference exception store by zero terminated string. Fixes regression introduced in commit f6bd4eb73cdf2a5bf954e497972842f39cabb7e3 Cc: Yi Yang <yi.y.yang@intel.com> Cc: Jonathan Brassow <jbrassow@redhat.com> Cc: stable@kernel.org Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm mpath: change to be request basedKiyoshi Ueda
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>
2009-06-22dm: disable interrupt when taking map_lockKiyoshi Ueda
This patch disables interrupt when taking map_lock to avoid lockdep warnings in request-based dm. request-based dm takes map_lock after taking queue_lock with disabling interrupt: spin_lock_irqsave(queue_lock) q->request_fn() == dm_request_fn() => dm_get_table() => read_lock(map_lock) while queue_lock could be (but isn't) taken in interrupt context. 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: Christof Schmitt <christof.schmitt@de.ibm.com> Acked-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm: do not set QUEUE_ORDERED_DRAIN if request basedKiyoshi Ueda
Request-based dm doesn't have barrier support yet. So we need to set QUEUE_ORDERED_DRAIN only for bio-based dm. Since the device type is decided at the first table loading time, the flag set is deferred until then. 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>
2009-06-22dm: enable request based optionKiyoshi Ueda
This patch enables request-based dm. o Request-based dm and bio-based dm coexist, since there are some target drivers which are more fitting to bio-based dm. Also, there are other bio-based devices in the kernel (e.g. md, loop). Since bio-based device can't receive struct request, there are some limitations on device stacking between bio-based and request-based. type of underlying device bio-based request-based ---------------------------------------------- bio-based OK OK request-based -- OK The device type is recognized by the queue flag in the kernel, so dm follows that. o The type of a dm device is decided at the first table binding time. Once the type of a dm device is decided, the type can't be changed. o Mempool allocations are deferred to at the table loading time, since mempools for request-based dm are different from those for bio-based dm and needed mempool type is fixed by the type of table. o Currently, request-based dm supports only tables that have a single target. To support multiple targets, we need to support request splitting or prevent bio/request from spanning multiple targets. The former needs lots of changes in the block layer, and the latter needs that all target drivers support merge() function. Both will take a time. 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>
2009-06-22dm: prepare for request based optionKiyoshi Ueda
This patch adds core functions for request-based dm. When struct mapped device (md) is initialized, md->queue has an I/O scheduler and the following functions are used for request-based dm as the queue functions: make_request_fn: dm_make_request() pref_fn: dm_prep_fn() request_fn: dm_request_fn() softirq_done_fn: dm_softirq_done() lld_busy_fn: dm_lld_busy() Actual initializations are done in another patch (PATCH 2). Below is a brief summary of how request-based dm behaves, including: - making request from bio - cloning, mapping and dispatching request - completing request and bio - suspending md - resuming md bio to request ============== md->queue->make_request_fn() (dm_make_request()) calls __make_request() for a bio submitted to the md. Then, the bio is kept in the queue as a new request or merged into another request in the queue if possible. Cloning and Mapping =================== Cloning and mapping are done in md->queue->request_fn() (dm_request_fn()), when requests are dispatched after they are sorted by the I/O scheduler. dm_request_fn() checks busy state of underlying devices using target's busy() function and stops dispatching requests to keep them on the dm device's queue if busy. It helps better I/O merging, since no merge is done for a request once it is dispatched to underlying devices. Actual cloning and mapping are done in dm_prep_fn() and map_request() called from dm_request_fn(). dm_prep_fn() clones not only request but also bios of the request so that dm can hold bio completion in error cases and prevent the bio submitter from noticing the error. (See the "Completion" section below for details.) After the cloning, the clone is mapped by target's map_rq() function and inserted to underlying device's queue using blk_insert_cloned_request(). Completion ========== Request completion can be hooked by rq->end_io(), but then, all bios in the request will have been completed even error cases, and the bio submitter will have noticed the error. To prevent the bio completion in error cases, request-based dm clones both bio and request and hooks both bio->bi_end_io() and rq->end_io(): bio->bi_end_io(): end_clone_bio() rq->end_io(): end_clone_request() Summary of the request completion flow is below: blk_end_request() for a clone request => blk_update_request() => bio->bi_end_io() == end_clone_bio() for each clone bio => Free the clone bio => Success: Complete the original bio (blk_update_request()) Error: Don't complete the original bio => blk_finish_request() => rq->end_io() == end_clone_request() => blk_complete_request() => dm_softirq_done() => Free the clone request => Success: Complete the original request (blk_end_request()) Error: Requeue the original request end_clone_bio() completes the original request on the size of the original bio in successful cases. Even if all bios in the original request are completed by that completion, the original request must not be completed yet to keep the ordering of request completion for the stacking. So end_clone_bio() uses blk_update_request() instead of blk_end_request(). In error cases, end_clone_bio() doesn't complete the original bio. It just frees the cloned bio and gives over the error handling to end_clone_request(). end_clone_request(), which is called with queue lock held, completes the clone request and the original request in a softirq context (dm_softirq_done()), which has no queue lock, to avoid a deadlock issue on submission of another request during the completion: - The submitted request may be mapped to the same device - Request submission requires queue lock, but the queue lock has been held by itself and it doesn't know that The clone request has no clone bio when dm_softirq_done() is called. So target drivers can't resubmit it again even error cases. Instead, they can ask dm core for requeueing and remapping the original request in that cases. suspend ======= Request-based dm uses stopping md->queue as suspend of the md. For noflush suspend, just stops md->queue. For flush suspend, inserts a marker request to the tail of md->queue. And dispatches all requests in md->queue until the marker comes to the front of md->queue. Then, stops dispatching request and waits for the all dispatched requests to complete. After that, completes the marker request, stops md->queue and wake up the waiter on the suspend queue, md->wait. resume ====== Starts md->queue. 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>
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>
2009-06-22dm: calculate queue limits during resume not loadMike Snitzer
Currently, device-mapper maintains a separate instance of 'struct queue_limits' for each table of each device. When the configuration of a device is to be changed, first its table is loaded and this structure is populated, then the device is 'resumed' and the calculated queue_limits are applied. This places restrictions on how userspace may process related devices, where it is often advantageous to 'load' tables for several devices at once before 'resuming' them together. As the new queue_limits only take effect after the 'resume', if they are changing and one device uses another, the latter must be 'resumed' before the former may be 'loaded'. This patch moves the calculation of these queue_limits out of the 'load' operation into 'resume'. Since we are no longer pre-calculating this struct, we no longer need to maintain copies within our dm structs. dm_set_device_limits() now passes the 'start' of the device's data area (aka pe_start) as the 'offset' to blk_stack_limits(). init_valid_queue_limits() is replaced by blk_set_default_limits(). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: martin.petersen@oracle.com Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm log: fix create_log_context to use logical_block_size of log deviceMike Snitzer
create_log_context() must use the logical_block_size from the log disk, where the I/O happens, not the target's logical_block_size. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm target:s introduce iterate devices fnMike Snitzer
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
2009-06-22dm table: establish queue limits by copying table limitsMike Snitzer
Copy the table's queue_limits to the DM device's request_queue. This properly initializes the queue's topology limits and also avoids having to track the evolution of 'struct queue_limits' in dm_table_set_restrictions() Also fixes a bug that was introduced in dm_table_set_restrictions() via commit ae03bf639a5027d27270123f5f6e3ee6a412781d. In addition to establishing 'bounce_pfn' in the queue's limits blk_queue_bounce_limit() also performs an allocation to setup the ISA DMA pool. This allocation resulted in "sleeping function called from invalid context" when called from dm_table_set_restrictions(). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm table: replace struct io_restrictions with struct queue_limitsMike Snitzer
Use blk_stack_limits() to stack block limits (including topology) rather than duplicate the equivalent within Device Mapper. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm table: validate device logical_block_sizeMike Snitzer
Impose necessary and sufficient conditions on a devices's table such that any incoming bio which respects its logical_block_size can be processed successfully. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm table: ensure targets are aligned to logical_block_sizeMike Snitzer
Ensure I/O is aligned to the logical block size of target devices. Rename check_device_area() to device_area_is_valid() for clarity and establish the device limits including the logical block size prior to calling it. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm ioctl: support cookies for udevMilan Broz
Add support for passing a 32 bit "cookie" into the kernel with the DM_SUSPEND, DM_DEV_RENAME and DM_DEV_REMOVE ioctls. The (unsigned) value of this cookie is returned to userspace alongside the uevents issued by these ioctls in the variable DM_COOKIE. This means the userspace process issuing these ioctls can be notified by udev after udev has completed any actions triggered. To minimise the interface extension, we pass the cookie into the kernel in the event_nr field which is otherwise unused when calling these ioctls. Incrementing the version number allows userspace to determine in advance whether or not the kernel supports the cookie. If the kernel does support this but userspace does not, there should be no impact as the new variable will just get ignored. Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm: sysfs add suspended attributePeter Rajnoha
Add a file named 'suspended' to each device-mapper device directory in sysfs. It holds the value 1 while the device is suspended. Otherwise it holds 0. Signed-off-by: Peter Rajnoha <prajnoha@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm table: improve warning message when devices not freed before destructionJonthan Brassow
Report any devices forgotten to be freed before a table is destroyed. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm mpath: add service time load balancerKiyoshi Ueda
This patch adds a service time oriented dynamic load balancer, dm-service-time, which selects the path with the shortest estimated service time for the incoming I/O. The service time is estimated by dividing the in-flight I/O size by a performance value of each path. The performance value can be given as a table argument at the table loading time. If no performance value is given, all paths are considered equal. 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>
2009-06-22dm mpath: add queue length load balancerKiyoshi Ueda
This patch adds a dynamic load balancer, dm-queue-length, which balances the number of in-flight I/Os across the paths. The code is based on the patch posted by Stefan Bader: https://www.redhat.com/archives/dm-devel/2005-October/msg00050.html 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>
2009-06-22dm mpath: add start_io and nr_bytes to path selectorsKiyoshi Ueda
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>
2009-06-22dm snapshot: use barrier when writing exception storeMikulas Patocka
Send barrier requests when updating the exception area. Exception area updates need to be ordered w.r.t. data writes, so that the writes are not reordered in hardware disk cache. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm io: retry after barrier errorMikulas Patocka
If -EOPNOTSUPP was returned and the request was a barrier request, retry it without barrier. Retry all regions for now. Barriers are submitted only for one-region requests, so it doesn't matter. (In the future, retries can be limited to the actual regions that failed.) Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm io: record eopnotsuppMikulas Patocka
Add another field, eopnotsupp_bits. It is subset of error_bits, representing regions that returned -EOPNOTSUPP. (The bit is set in both error_bits and eopnotsupp_bits). This value will be used in further patches. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm snapshot: support barriersMikulas Patocka
Flush support for dm-snapshot target. This patch just forwards the flush request to either the origin or the snapshot device. (It doesn't flush exception store metadata.) Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm mpath: support barriersMikulas Patocka
Flush support for dm-multipath target. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm delay: support barriersMikulas Patocka
Flush support for dm-delay target. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm crypt: support flushMikulas Patocka
Flush support for dm-crypt target. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm: stripe support flushMikulas Patocka
Flush support for the stripe target. This sets ti->num_flush_requests to the number of stripes and remaps individual flush requests to the appropriate stripe devices. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm: linear support flushMikulas Patocka
Flush support for the linear target. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm: send empty barriers to targets in dm_flushMikulas Patocka
Pass empty barrier flushes to the targets in dm_flush(). Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm: initialise tio in alloc_tioAlasdair G Kergon
Move repeated dm_target_io initialisation inside alloc_tio(). Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm: introduce num_flush_requestsMikulas Patocka
Introduce num_flush_requests for a target to set to say how many flush instructions (empty barriers) it wants to receive. These are sent by __clone_and_map_empty_barrier with map_info->flush_request going from 0 to (num_flush_requests - 1). Old targets without flush support won't receive any flush requests. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm: remove check that prevents mapping empty biosMikulas Patocka
Remove the check that the size of the cloned bio is not zero because a subsequent patch needs to send zero-sized barriers down this path. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm: remove EOPNOTSUPP for barriersMikulas Patocka
If the underlying device doesn't support barriers and dm receives a barrier, it waits until all requests on that device drain so it no longer needs to report -EOPNOTSUPP to the caller. This patch deals with the confusing situation when moving a volume from one physical device to another triggers an EOPNOTSUPP on a volume that didn't report it before. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm: store only first barrier errorMikulas Patocka
With the following patches, more than one error can occur during processing. Change md->barrier_error so that only the first one is recorded and returned to the caller. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm: process requeue in dm_wq_workMikulas Patocka
If barrier request was returned with DM_ENDIO_REQUEUE, requeue it in dm_wq_work instead of dec_pending. This allows us to correctly handle a situation when some targets are asking for a requeue and other targets signal an error. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm: make dm_flush return voidMikulas Patocka
Make dm_flush return void. The first error during flush is stored in md->barrier_error instead. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm: always hold bdev referenceMikulas Patocka
Fix a potential deadlock when creating multiple snapshots by holding a reference to struct block_device for the whole lifecycle of every dm device instead of obtaining it independently at each point it is needed. bdget_disk() was called while the device was being suspended, in dm_suspend(). However there could be other devices already suspended, for example when creating additional snapshots of a device. bdget_disk() can wait for IO and allocate memory resulting in waiting for the already-suspended device - deadlock. This patch changes the code so that it gets the reference to struct block_device when struct mapped_device is allocated and initialized in alloc_dev() where it is always OK to allocate memory or wait for I/O. It drops the reference when it is destroyed in free_dev(). Thus there is no call to bdget_disk() while any device is suspended. Previously unlock_fs() was called only if bdev was held. Now it is called unconditionally, but the superfluous calls are harmless because it returns immediately if the filesystem was not previously frozen. This patch also now allows the device size to be changed in a noflush suspend because the bdev is held. This has no adverse effect. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>