- 10 9月, 2010 6 次提交
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由 Mike Snitzer 提交于
Rename __clone_and_map_flush to __clone_and_map_empty_flush for added clarity. Simplify logic associated with REQ_FLUSH conditionals. Introduce a BUG_ON() and add a few more helpful comments to the code so that it is clear that all flushes are empty. Cleanup __split_and_process_bio() so that an empty flush isn't processed by a 'sector_count' focused while loop. Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NTejun Heo <tj@kernel.org> Signed-off-by: NJens Axboe <jaxboe@fusionio.com>
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由 Kiyoshi Ueda 提交于
Now queue_io() is called from dec_pending(), which may be called with interrupts disabled, so queue_io() must not enable interrupts unconditionally and must save/restore the current interrupts status. Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: NTejun Heo <tj@kernel.org> Signed-off-by: NJens Axboe <jaxboe@fusionio.com>
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由 Tejun Heo 提交于
Unlike REQ_HARDBARRIER, REQ_FLUSH/FUA doesn't mandate any ordering against other bio's. This patch relaxes ordering around flushes. * A flush bio is no longer deferred to workqueue directly. It's processed like other bio's but __split_and_process_bio() uses md->flush_bio as the clone source. md->flush_bio is initialized to empty flush during md initialization and shared for all flushes. * As a flush bio now travels through the same execution path as other bio's, there's no need for dedicated error handling path either. It can use the same error handling path in dec_pending(). Dedicated error handling removed along with md->flush_error. * When dec_pending() detects that a flush has completed, it checks whether the original bio has data. If so, the bio is queued to the deferred list w/ REQ_FLUSH cleared; otherwise, it's completed. * As flush sequencing is handled in the usual issue/completion path, dm_wq_work() no longer needs to handle flushes differently. Now its only responsibility is re-issuing deferred bio's the same way as _dm_request() would. REQ_FLUSH handling logic including process_flush() is dropped. * There's no reason for queue_io() and dm_wq_work() write lock dm->io_lock. queue_io() now only uses md->deferred_lock and dm_wq_work() read locks dm->io_lock. * bio's no longer need to be queued on the deferred list while a flush is in progress making DMF_QUEUE_IO_TO_THREAD unncessary. Drop it. This avoids stalling the device during flushes and simplifies the implementation. Signed-off-by: NTejun Heo <tj@kernel.org> Signed-off-by: NJens Axboe <jaxboe@fusionio.com>
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由 Tejun Heo 提交于
This patch converts request-based dm to support the new REQ_FLUSH/FUA. The original request-based flush implementation depended on request_queue blocking other requests while a barrier sequence is in progress, which is no longer true for the new REQ_FLUSH/FUA. In general, request-based dm doesn't have infrastructure for cloning one source request to multiple targets, but the original flush implementation had a special mostly independent path which can issue flushes to multiple targets and sequence them. However, the capability isn't currently in use and adds a lot of complexity. Moreoever, it's unlikely to be useful in its current form as it doesn't make sense to be able to send out flushes to multiple targets when write requests can't be. This patch rips out special flush code path and deals handles REQ_FLUSH/FUA requests the same way as other requests. The only special treatment is that REQ_FLUSH requests use the block address 0 when finding target, which is enough for now. * added BUG_ON(!dm_target_is_valid(ti)) in dm_request_fn() as suggested by Mike Snitzer Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NMike Snitzer <snitzer@redhat.com> Tested-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NJens Axboe <jaxboe@fusionio.com>
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由 Tejun Heo 提交于
This patch converts bio-based dm to support REQ_FLUSH/FUA instead of now deprecated REQ_HARDBARRIER. * -EOPNOTSUPP handling logic dropped. * Preflush is handled as before but postflush is dropped and replaced with passing down REQ_FUA to member request_queues. This replaces one array wide cache flush w/ member specific FUA writes. * __split_and_process_bio() now calls __clone_and_map_flush() directly for flushes and guarantees all FLUSH bio's going to targets are zero ` length. * It's now guaranteed that all FLUSH bio's which are passed onto dm targets are zero length. bio_empty_barrier() tests are replaced with REQ_FLUSH tests. * Empty WRITE_BARRIERs are replaced with WRITE_FLUSHes. * Dropped unlikely() around REQ_FLUSH tests. Flushes are not unlikely enough to be marked with unlikely(). * Block layer now filters out REQ_FLUSH/FUA bio's if the request_queue doesn't support cache flushing. Advertise REQ_FLUSH | REQ_FUA capability. * Request based dm isn't converted yet. dm_init_request_based_queue() resets flush support to 0 for now. To avoid disturbing request based dm code, dm->flush_error is added for bio based dm while requested based dm continues to use dm->barrier_error. Lightly tested linear, stripe, raid1, snap and crypt targets. Please proceed with caution as I'm not familiar with the code base. Signed-off-by: NTejun Heo <tj@kernel.org> Cc: dm-devel@redhat.com Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: NJens Axboe <jaxboe@fusionio.com>
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由 Tejun Heo 提交于
Barrier is deemed too heavy and will soon be replaced by FLUSH/FUA requests. Deprecate barrier. All REQ_HARDBARRIERs are failed with -EOPNOTSUPP and blk_queue_ordered() is replaced with simpler blk_queue_flush(). blk_queue_flush() takes combinations of REQ_FLUSH and FUA. If a device has write cache and can flush it, it should set REQ_FLUSH. If the device can handle FUA writes, it should also set REQ_FUA. All blk_queue_ordered() users are converted. * ORDERED_DRAIN is mapped to 0 which is the default value. * ORDERED_DRAIN_FLUSH is mapped to REQ_FLUSH. * ORDERED_DRAIN_FLUSH_FUA is mapped to REQ_FLUSH | REQ_FUA. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NBoaz Harrosh <bharrosh@panasas.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Chris Wright <chrisw@sous-sol.org> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> Cc: David S. Miller <davem@davemloft.net> Cc: Alasdair G Kergon <agk@redhat.com> Cc: Pierre Ossman <drzeus@drzeus.cx> Cc: Stefan Weinhuber <wein@de.ibm.com> Signed-off-by: NJens Axboe <jaxboe@fusionio.com>
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- 12 8月, 2010 10 次提交
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由 Mike Snitzer 提交于
Update __clone_and_map_discard to loop across all targets in a DM device's table when it processes a discard bio. If a discard crosses a target boundary it must be split accordingly. Update __issue_target_requests and __issue_target_request to allow a cloned discard bio to have a custom start sector and size. Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Mike Snitzer 提交于
Split max_io_len_target_boundary out of max_io_len so that the discard support can make use of it without duplicating max_io_len code. Avoiding max_io_len's split_io logic enables DM's discard support to submit the entire discard request to a target. But discards must still be split on target boundaries. Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Mike Snitzer 提交于
Rename __flush_target to __issue_target_request now that it is used to issue both flush and discard requests. Introduce __issue_target_requests as a convenient wrapper to __issue_target_request 'num_flush_requests' or 'num_discard_requests' times per target. Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Mike Snitzer 提交于
Allow discards to be passed through to linear mappings if at least one underlying device supports it. Discards will be forwarded only to devices that support them. A target that supports discards should set num_discard_requests to indicate how many times each discard request must be submitted to it. Verify table's underlying devices support discards prior to setting the associated DM device as capable of discards (via QUEUE_FLAG_DISCARD). Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NMikulas Patocka <mpatocka@redhat.com> Reviewed-by: NJoe Thornber <thornber@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Mike Snitzer 提交于
'target_request_nr' is a more generic name that reflects the fact that it will be used for both flush and discard support. Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Mike Snitzer 提交于
Change bio-based mapped devices no longer to have a fully initialized request_queue (request_fn, elevator, etc). This means bio-based DM devices no longer register elevator sysfs attributes ('iosched/' tree or 'scheduler' other than "none"). In contrast, a request-based DM device will continue to have a full request_queue and will register elevator sysfs attributes. Therefore a user can determine a DM device's type by checking if elevator sysfs attributes exist. First allocate a minimalist request_queue structure for a DM device (needed for both bio and request-based DM). Initialization of a full request_queue is deferred until it is known that the DM device is request-based, at the end of the table load sequence. Factor DM device's request_queue initialization: - common to both request-based and bio-based into dm_init_md_queue(). - specific to request-based into dm_init_request_based_queue(). The md->type_lock mutex is used to protect md->queue, in addition to md->type, during table_load(). A DM device's first table_load will establish the immutable md->type. But md->queue initialization, based on md->type, may fail at that time (because blk_init_allocated_queue cannot allocate memory). Therefore any subsequent table_load must (re)try dm_setup_md_queue independently of establishing md->type. Signed-off-by: NMike Snitzer <snitzer@redhat.com> Acked-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Mike Snitzer 提交于
Determine whether a mapped device is bio-based or request-based when loading its first (inactive) table and don't allow that to be changed later. This patch performs different device initialisation in each of the two cases. (We don't think it's necessary to add code to support changing between the two types.) Allowed md->type transitions: DM_TYPE_NONE to DM_TYPE_BIO_BASED DM_TYPE_NONE to DM_TYPE_REQUEST_BASED We now prevent table_load from replacing the inactive table with a conflicting type of table even after an explicit table_clear. Introduce 'type_lock' into the struct mapped_device to protect md->type and to prepare for the next patch that will change the queue initialization and allocate memory while md->type_lock is held. Signed-off-by: NMike Snitzer <snitzer@redhat.com> Acked-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com> drivers/md/dm-ioctl.c | 15 +++++++++++++++ drivers/md/dm.c | 37 ++++++++++++++++++++++++++++++------- drivers/md/dm.h | 5 +++++ include/linux/dm-ioctl.h | 4 ++-- 4 files changed, 52 insertions(+), 9 deletions(-)
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由 Mikulas Patocka 提交于
When processing barriers, skip the second flush if processing the bio failed with -EOPNOTSUPP. This can happen with discard+barrier requests. If the device doesn't support discard, there would be two useless SYNCHRONIZE CACHE commands. The first dm_flush cannot be so easily optimized out, so we leave it there. Previously, -EOPNOTSUPP could be received in dec_pending only with empty barriers and we ignored that error, assuming the device not supporting cache flushes has cache always consistent. With the addition of discard barriers, this -EOPNOTSUPP can also be generated by discards and we must record it in md->barrier_error for process_barrier. Signed-off-by: NMikulas Patocka <mpatocka@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Kiyoshi Ueda 提交于
This patch separates the device deletion code from dm_put() to make sure the deletion happens in the process context. By this patch, device deletion always occurs in an ioctl (process) context and dm_put() can be called in interrupt context. As a result, the request-based dm's bad dm_put() usage pointed out by Mikulas below disappears. http://marc.info/?l=dm-devel&m=126699981019735&w=2 Without this patch, I confirmed there is a case to crash the system: dm_put() => dm_table_destroy() => vfree() => BUG_ON(in_interrupt()) Some more backgrounds and details: In request-based dm, a device opener can remove a mapped_device while the last request is still completing, because bios in the last request complete first and then the device opener can close and remove the mapped_device before the last request completes: CPU0 CPU1 ================================================================= <<INTERRUPT>> blk_end_request_all(clone_rq) blk_update_request(clone_rq) bio_endio(clone_bio) == end_clone_bio blk_update_request(orig_rq) bio_endio(orig_bio) <<I/O completed>> dm_blk_close() dev_remove() dm_put(md) <<Free md>> blk_finish_request(clone_rq) .... dm_end_request(clone_rq) free_rq_clone(clone_rq) blk_end_request_all(orig_rq) rq_completed(md) So request-based dm used dm_get()/dm_put() to hold md for each I/O until its request completion handling is fully done. However, the final dm_put() can call the device deletion code which must not be run in interrupt context and may cause kernel panic. To solve the problem, this patch moves the device deletion code, dm_destroy(), to predetermined places that is actually deleting the mapped_device in ioctl (process) context, and changes dm_put() just to decrement the reference count of the mapped_device. By this change, dm_put() can be used in any context and the symmetric model below is introduced: dm_create(): create a mapped_device dm_destroy(): destroy a mapped_device dm_get(): increment the reference count of a mapped_device dm_put(): decrement the reference count of a mapped_device dm_destroy() waits for all references of the mapped_device to disappear, then deletes the mapped_device. dm_destroy() uses active waiting with msleep(1), since deleting the mapped_device isn't performance-critical task. And since at this point, nobody opens the mapped_device and no new reference will be taken, the pending counts are just for racing completing activity and will eventually decrease to zero. For the unlikely case of the forced module unload, dm_destroy_immediate(), which doesn't wait and forcibly deletes the mapped_device, is also introduced and used in dm_hash_remove_all(). Otherwise, "rmmod -f" may be stuck and never return. And now, because the mapped_device is deleted at this point, subsequent accesses to the mapped_device may cause NULL pointer references. Cc: stable@kernel.org Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Kiyoshi Ueda 提交于
This patch prevents access to mapped_device which is being deleted. Currently, even after a mapped_device has been removed from the hash, it could be accessed through idr_find() using minor number. That could cause a race and NULL pointer reference below: CPU0 CPU1 ------------------------------------------------------------------ dev_remove(param) down_write(_hash_lock) dm_lock_for_deletion(md) spin_lock(_minor_lock) set_bit(DMF_DELETING) spin_unlock(_minor_lock) __hash_remove(hc) up_write(_hash_lock) dev_status(param) md = find_device(param) down_read(_hash_lock) __find_device_hash_cell(param) dm_get_md(param->dev) md = dm_find_md(dev) spin_lock(_minor_lock) md = idr_find(MINOR(dev)) spin_unlock(_minor_lock) dm_put(md) free_dev(md) dm_get(md) up_read(_hash_lock) __dev_status(md, param) dm_put(md) This patch fixes such problems. Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: stable@kernel.org Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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- 08 8月, 2010 5 次提交
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由 Arnd Bergmann 提交于
The open and release block_device_operations are currently called with the BKL held. In order to change that, we must first make sure that all drivers that currently rely on this have no regressions. This blindly pushes the BKL into all .open and .release operations for all block drivers to prepare for the next step. The drivers can subsequently replace the BKL with their own locks or remove it completely when it can be shown that it is not needed. The functions blkdev_get and blkdev_put are the only remaining users of the big kernel lock in the block layer, besides a few uses in the ioctl code, none of which need to serialize with blkdev_{get,put}. Most of these two functions is also under the protection of bdev->bd_mutex, including the actual calls to ->open and ->release, and the common code does not access any global data structures that need the BKL. Signed-off-by: NArnd Bergmann <arnd@arndb.de> Acked-by: NChristoph Hellwig <hch@infradead.org> Signed-off-by: NJens Axboe <jaxboe@fusionio.com>
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由 FUJITA Tomonori 提交于
This removes q->prepare_flush_fn completely (changes the blk_queue_ordered API). Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Reviewed-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NJens Axboe <jaxboe@fusionio.com>
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由 FUJITA Tomonori 提交于
use REQ_FLUSH flag instead. Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Alasdair G Kergon <agk@redhat.com> Reviewed-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NJens Axboe <jaxboe@fusionio.com>
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由 Christoph Hellwig 提交于
Remove the current bio flags and reuse the request flags for the bio, too. This allows to more easily trace the type of I/O from the filesystem down to the block driver. There were two flags in the bio that were missing in the requests: BIO_RW_UNPLUG and BIO_RW_AHEAD. Also I've renamed two request flags that had a superflous RW in them. Note that the flags are in bio.h despite having the REQ_ name - as blkdev.h includes bio.h that is the only way to go for now. Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NJens Axboe <jaxboe@fusionio.com>
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由 Christoph Hellwig 提交于
Remove all the trivial wrappers for the cmd_type and cmd_flags fields in struct requests. This allows much easier grepping for different request types instead of unwinding through macros. Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NJens Axboe <jaxboe@fusionio.com>
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- 06 3月, 2010 3 次提交
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由 Peter Rajnoha 提交于
Set a new DM_UEVENT_GENERATED_FLAG when returning from ioctls to indicate that a uevent was actually generated. This tells the userspace caller that it may need to wait for the event to be processed. Signed-off-by: NPeter Rajnoha <prajnoha@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Mikulas Patocka 提交于
Free the dm_io structure before calling bio_endio() instead of after it, to ensure that the io_pool containing it is not referenced after it is freed. This partially fixes a problem described here https://www.redhat.com/archives/dm-devel/2010-February/msg00109.html thread 1: bio_endio(bio, io_error); /* scheduling happens */ thread 2: close the device remove the device thread 1: free_io(md, io); Thread 2, when removing the device, sees non-empty md->io_pool (because the io hasn't been freed by thread 1 yet) and may crash with BUG in mempool_free. Thread 1 may also crash, when freeing into a nonexisting mempool. To fix this we must make sure that bio_endio() is the last call and the md structure is not accessed afterwards. There is another bio_endio in process_barrier, but it is called from the thread and the thread is destroyed prior to freeing the mempools, so this call is not affected by the bug. A similar bug exists with module unloads - the module may be unloaded immediately after bio_endio - but that is more difficult to fix. Signed-off-by: NMikulas Patocka <mpatocka@redhat.com> Cc: stable@kernel.org Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Kiyoshi Ueda 提交于
Remove the dm_get() in dm_table_get_md() because dm_table_get_md() could be called from presuspend/postsuspend, which are called while mapped_device is in DMF_FREEING state, where dm_get() is not allowed. Justification for that is the lifetime of both objects: As far as the current dm design/implementation, mapped_device is never freed while targets are doing something, because dm core waits for targets to become quiet in dm_put() using presuspend/postsuspend. So targets should be able to touch mapped_device without holding reference count of the mapped_device, and we should allow targets to touch mapped_device even if it is in DMF_FREEING state. Backgrounds: I'm trying to remove the multipath internal queue, since dm core now has a generic queue for request-based dm. In the patch-set, the multipath target wants to request dm core to start/stop queue. One of such start/stop requests can happen during postsuspend() while the target waits for pg-init to complete, because the target stops queue when starting pg-init and tries to restart it when completing pg-init. Since queue belongs to mapped_device, it involves calling dm_table_get_md() and dm_put(). On the other hand, postsuspend() is called in dm_put() for mapped_device which is in DMF_FREEING state, and that triggers BUG_ON(DMF_FREEING) in the 2nd dm_put(). I had tried to solve this problem by changing only multipath not to touch mapped_device which is in DMF_FREEING state, but I couldn't and I came up with a question why we need dm_get() in dm_table_get_md(). Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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- 17 2月, 2010 1 次提交
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由 Kiyoshi Ueda 提交于
This patch fixes the problem that system may stall if target's ->map_rq returns DM_MAPIO_REQUEUE in map_request(). E.g. stall happens on 1 CPU box when a dm-mpath device with queue_if_no_path bounces between all-paths-down and paths-up on I/O load. When target's ->map_rq returns DM_MAPIO_REQUEUE, map_request() requeues the request and returns to dm_request_fn(). Then, dm_request_fn() doesn't exit the I/O dispatching loop and continues processing the requeued request again. This map and requeue loop can be done with interrupt disabled, so 1 CPU system can be stalled if this situation happens. For example, commands below can stall my 1 CPU box within 1 minute or so: # dmsetup table mp mp: 0 2097152 multipath 1 queue_if_no_path 0 1 1 service-time 0 1 2 8:144 1 1 # while true; do dd if=/dev/mapper/mp of=/dev/null bs=1M count=100; done & # while true; do \ > dmsetup message mp 0 "fail_path 8:144" \ > dmsetup suspend --noflush mp \ > dmsetup resume mp \ > dmsetup message mp 0 "reinstate_path 8:144" \ > done To fix the problem above, this patch changes dm_request_fn() to exit the I/O dispatching loop once if a request is requeued in map_request(). Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: stable@kernel.org Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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- 11 12月, 2009 15 次提交
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由 Kiyoshi Ueda 提交于
This patch adds the exported dm_suspended() function so that targets can check whether or not they are suspended. Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: Mike Anderson <andmike@linux.vnet.ibm.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Kiyoshi Ueda 提交于
This patch renames dm_suspended() to dm_suspended_md() and keeps it internal to dm. No functional change. Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: Mike Anderson <andmike@linux.vnet.ibm.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Kiyoshi Ueda 提交于
This patch moves DMF_SUSPENDED flag set before postsuspend. No one should care about the ordering, because the flag set and the postsuspend are protected by a single lock, md->suspend_lock, and all strict flag-checkers take the lock. Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: Mike Anderson <andmike@linux.vnet.ibm.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Jun'ichi Nomura 提交于
This patch adds a remapping trace to request-based dm. BIO-based dm already has the equivalent tracepoint. For example, under this dm stack (linear LV on multipath): # dmsetup ls --tree -o ascii vg-lv0 (253:1) `-mpath0 (253:0) |- (8:160) |- (66:80) |- (65:176) `- (65:160) Trace of 'dd of=/dev/vg/lv0 bs=128k count=1 oflag=direct' looks like this: without the patch: dd-6674 [000] 539.727384: block_bio_queue: 253,1 WS 0 + 256 [dd] dd-6674 [000] 539.727392: block_remap: 253,0 WS 384 + 256 <- (253,1) 0 dd-6674 [000] 539.727394: block_bio_queue: 253,0 WS 384 + 256 [dd] dd-6674 [000] 539.727405: block_getrq: 253,0 WS 384 + 256 [dd] dd-6674 [000] 539.727409: block_plug: [dd] dd-6674 [000] 539.727410: block_rq_insert: 253,0 W 0 () 384 + 256 [dd] dd-6674 [000] 539.727416: block_rq_issue: 253,0 W 0 () 384 + 256 [dd] dd-6674 [000] 539.727426: block_rq_insert: 65,176 W 0 () 384 + 256 [dd] dd-6674 [000] 539.727427: block_rq_issue: 65,176 W 0 () 384 + 256 [dd] ... and with the patch: (the line with '**' is the trace added by this patch) dd-6617 [002] 162.914301: block_bio_queue: 253,1 WS 0 + 256 [dd] dd-6617 [002] 162.914314: block_remap: 253,0 WS 384 + 256 <- (253,1) 0 dd-6617 [002] 162.914316: block_bio_queue: 253,0 WS 384 + 256 [dd] dd-6617 [002] 162.914331: block_getrq: 253,0 WS 384 + 256 [dd] dd-6617 [002] 162.914335: block_plug: [dd] dd-6617 [002] 162.914337: block_rq_insert: 253,0 W 0 () 384 + 256 [dd] dd-6617 [002] 162.914347: block_rq_issue: 253,0 W 0 () 384 + 256 [dd] **dd-6617 [002] 162.914356: block_rq_remap: 65,176 W 384 + 256 <- (253,0) 384 dd-6617 [002] 162.914358: block_rq_insert: 65,176 W 0 () 384 + 256 [dd] dd-6617 [002] 162.914359: block_rq_issue: 65,176 W 0 () 384 + 256 [dd] ... Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Alasdair G Kergon 提交于
When swapping a new table into place, retain the old table until its replacement is in place. An old check for an empty table is removed because this is enforced in populate_table(). __unbind() becomes redundant when followed by __bind(). Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Alasdair G Kergon 提交于
When replacing a mapped device's table during a 'resume', delay the destruction of the old table until the new one is successfully in place. This will make it easier for a later patch to transfer internal state information from the old table to the new one (something we do not currently support) while giving us more options for reversion if a later part of the operation fails. Devices are always in the suspended state during dm_swap_table(). This patch reinforces the requirement that all I/O must have been flushed from the table targets while in this state (including any in workqueues). In the case of 'noflush' suspending, unprocessed I/O should have been 'pushed back' to the dm core prior to this point, for resubmission after the new table is in place. Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Mike Anderson 提交于
Add dm_deleting_md to check whether or not a given mapped device is currently being deleted. Signed-off-by: NMike Anderson <andmike@linux.vnet.ibm.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Alasdair G Kergon 提交于
Rename dm_get_table to dm_get_live_table. Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Kiyoshi Ueda 提交于
This patch adds barrier support for request-based dm. CORE DESIGN The design is basically same as bio-based dm, which emulates barrier by mapping empty barrier bios before/after a barrier I/O. But request-based dm has been using struct request_queue for I/O queueing, so the block-layer's barrier mechanism can be used. o Summary of the block-layer's behavior (which is depended by dm-core) Request-based dm uses QUEUE_ORDERED_DRAIN_FLUSH ordered mode for I/O barrier. It means that when an I/O requiring barrier is found in the request_queue, the block-layer makes pre-flush request and post-flush request just before and just after the I/O respectively. After the ordered sequence starts, the block-layer waits for all in-flight I/Os to complete, then gives drivers the pre-flush request, the barrier I/O and the post-flush request one by one. It means that the request_queue is stopped automatically by the block-layer until drivers complete each sequence. o dm-core For the barrier I/O, treats it as a normal I/O, so no additional code is needed. For the pre/post-flush request, flushes caches by the followings: 1. Make the number of empty barrier requests required by target's num_flush_requests, and map them (dm_rq_barrier()). 2. Waits for the mapped barriers to complete (dm_rq_barrier()). If error has occurred, save the error value to md->barrier_error (dm_end_request()). (*) Basically, the first reported error is taken. But -EOPNOTSUPP supersedes any error and DM_ENDIO_REQUEUE follows. 3. Requeue the pre/post-flush request if the error value is DM_ENDIO_REQUEUE. Otherwise, completes with the error value (dm_rq_barrier_work()). The pre/post-flush work above is done in the kernel thread (kdmflush) context, since memory allocation which might sleep is needed in dm_rq_barrier() but sleep is not allowed in dm_request_fn(), which is an irq-disabled context. Also, clones of the pre/post-flush request share an original, so such clones can't be completed using the softirq context. Instead, complete them in the context of underlying device drivers. It should be safe since there is no I/O dispatching during the completion of such clones. For suspend, the workqueue of kdmflush needs to be flushed after the request_queue has been stopped. Otherwise, the next flush work can be kicked even after the suspend completes. TARGET INTERFACE No new interface is added. Just use the existing num_flush_requests in struct target_type as same as bio-based dm. Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Kiyoshi Ueda 提交于
This patch moves dm_end_request() to make the next patch more readable. No functional change. Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Kiyoshi Ueda 提交于
This patch factors out the clone completion code, dm_done(), from dm_softirq_done() in preparation for a subsequent patch. No functional change. dm_done() will be used in barrier completion, which can't use and doesn't need softirq. The softirq_done callback needs to get a clone from an original request but it can't in the case of barrier, where an original request is shared by multiple clones. On the other hand, the completion of barrier clones doesn't involve re-submitting requests, which was the primary reason of the need for softirq. Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Kiyoshi Ueda 提交于
This patch changes the counter for the number of in_flight I/Os to md->pending from q->in_flight in preparation for a later patch. No functional change. Request-based dm used q->in_flight to count the number of in-flight clones assuming the counter is always incremented for an in-flight original request and original:clone is 1:1 relationship. However, it this no longer true for barrier requests. So use md->pending to count the number of in-flight clones. Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Kiyoshi Ueda 提交于
The semantics of bio-based dm were changed recently in the case of suspend with "--nolockfs" but without "--noflush". Before 2.6.30, I/Os submitted before the suspend invocation were always flushed. From 2.6.30 onwards, I/Os submitted before the suspend invocation might not be flushed. (For details, see http://marc.info/?t=123994433400003&r=1&w=2) This patch brings the behaviour of request-based dm into line with bio-based dm, simplifying the code and preparing for a subsequent patch that will wait for all in_flight I/Os to complete without stopping request_queue and use dm_wait_for_completion() for it. This change in semantics simplifies the suspend code as follows: o Suspend is implemented as stopping request_queue in request-based dm, and all I/Os are queued in the request_queue even after suspend is invoked. o In the old semantics, we had to track whether I/Os were queued before or after the suspend invocation, so a special barrier-like request called 'suspend marker' was introduced. o With the new semantics, we don't need to flush any I/O so we can remove the marker and the code related to the marker handling and I/O flushing. After removing this codes, the suspend sequence is now: 1. Flush all I/Os by lock_fs() if needed. 2. Stop dispatching any I/O by stopping the request_queue. 3. Wait for all in-flight I/Os to be completed or requeued. Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Kiyoshi Ueda 提交于
This patch factors out the request cloning code in dm_prep_fn() as clone_rq(). No functional change. This patch is a preparation for a later patch in this series which needs to make clones from an original barrier request. Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Kiyoshi Ueda 提交于
This patch adds the gfp_mask argument to alloc_rq_tio(). No functional change. This patch is a preparation for a later patch in this series which needs to allocate tio (for barrier I/O) with different allocation flag (GFP_NOIO) from the one in the normal I/O code path. Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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