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2011-03-25block: fix issue with calling blk_stop_queue() from the request_fn handlerJens Axboe
When the queue work handler was converted to delayed work, the stopping was inadvertently made sync as well. Change this back to being async stop, using __cancel_delayed_work() instead of cancel_delayed_work(). Reported-by: Jeremy Fitzhardinge <jeremy@goop.org> Reported-by: Chris Mason <chris.mason@oracle.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-25block: fix bug with inserting flush requests as sort/mergeJens Axboe
With the introduction of the on-stack plugging, we would assume that any request being inserted was a normal file system request. As flush/fua requires a special insert mode, this caused problems. Fix this up by checking for this in flush_plug_list() and use the appropriate insert mechanism. Big thanks goes to Markus Tripplesdorf for tirelessly testing patches, and to Sergey Senozhatsky for helping find the real issue. Reported-by: Markus Tripplesdorf <markus@trippelsdorf.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-24Merge branch 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds
* 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block: (65 commits) Documentation/iostats.txt: bit-size reference etc. cfq-iosched: removing unnecessary think time checking cfq-iosched: Don't clear queue stats when preempt. blk-throttle: Reset group slice when limits are changed blk-cgroup: Only give unaccounted_time under debug cfq-iosched: Don't set active queue in preempt block: fix non-atomic access to genhd inflight structures block: attempt to merge with existing requests on plug flush block: NULL dereference on error path in __blkdev_get() cfq-iosched: Don't update group weights when on service tree fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going away block: Require subsystems to explicitly allocate bio_set integrity mempool jbd2: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging jbd: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging fs: make fsync_buffers_list() plug mm: make generic_writepages() use plugging blk-cgroup: Add unaccounted time to timeslice_used. block: fixup plugging stubs for !CONFIG_BLOCK block: remove obsolete comments for blkdev_issue_zeroout. blktrace: Use rq->cmd_flags directly in blk_add_trace_rq. ... Fix up conflicts in fs/{aio.c,super.c}
2011-03-23cfq-iosched: removing unnecessary think time checkingLi, Shaohua
Removing think time checking. A high thinktime queue might means the queue dispatches several requests and then do away. Limitting such queue seems meaningless. And also this can simplify code. This is suggested by Vivek. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-23cfq-iosched: Don't clear queue stats when preempt.Justin TerAvest
For v2, I added back lines to cfq_preempt_queue() that were removed during updates for accounting unaccounted_time. Thanks for pointing out that I'd missed these, Vivek. Previous commit "cfq-iosched: Don't set active queue in preempt" wrongly cleared stats for preempting queues when it shouldn't have, because when we choose a queue to preempt, it still isn't necessarily scheduled next. Thanks to Vivek Goyal for figuring this out and understanding how the preemption code works. Signed-off-by: Justin TerAvest <teravest@google.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-22blk-throttle: Reset group slice when limits are changedVivek Goyal
Lina reported that if throttle limits are initially very high and then dropped, then no new bio might be dispatched for a long time. And the reason being that after dropping the limits we don't reset the existing slice and do the rate calculation with new low rate and account the bios dispatched at high rate. To fix it, reset the slice upon rate change. https://lkml.org/lkml/2011/3/10/298 Another problem with very high limit is that we never queued the bio on throtl service tree. That means we kept on extending the group slice but never trimmed it. Fix that also by regulary trimming the slice even if bio is not being queued up. Reported-by: Lina Lu <lulina_nuaa@foxmail.com> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-22blk-cgroup: Only give unaccounted_time under debugJustin TerAvest
This change moves unaccounted_time to only be reported when CONFIG_DEBUG_BLK_CGROUP is true. Signed-off-by: Justin TerAvest <teravest@google.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-22cfq-iosched: Don't set active queue in preemptJustin TerAvest
Commit "Add unaccounted time to timeslice_used" changed the behavior of cfq_preempt_queue to set cfqq active. Vivek pointed out that other preemption rules might get involved, so we shouldn't manually set which queue is active. This cleans up the code to just clear the queue stats at preemption time. Signed-off-by: Justin TerAvest <teravest@google.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-21block: attempt to merge with existing requests on plug flushJens Axboe
One of the disadvantages of on-stack plugging is that we potentially lose out on merging since all pending IO isn't always visible to everybody. When we flush the on-stack plugs, right now we don't do any checks to see if potential merge candidates could be utilized. Correct this by adding a new insert variant, ELEVATOR_INSERT_SORT_MERGE. It works just ELEVATOR_INSERT_SORT, but first checks whether we can merge with an existing request before doing the insertion (if we fail merging). This fixes a regression with multiple processes issuing IO that can be merged. Thanks to Shaohua Li <shaohua.li@intel.com> for testing and fixing an accounting bug. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-17Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6Linus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (170 commits) [SCSI] scsi_dh_rdac: Add MD36xxf into device list [SCSI] scsi_debug: add consecutive medium errors [SCSI] libsas: fix ata list corruption issue [SCSI] hpsa: export resettable host attribute [SCSI] hpsa: move device attributes to avoid forward declarations [SCSI] scsi_debug: Logical Block Provisioning (SBC3r26) [SCSI] sd: Logical Block Provisioning update [SCSI] Include protection operation in SCSI command trace [SCSI] hpsa: fix incorrect PCI IDs and add two new ones (2nd try) [SCSI] target: Fix volume size misreporting for volumes > 2TB [SCSI] bnx2fc: Broadcom FCoE offload driver [SCSI] fcoe: fix broken fcoe interface reset [SCSI] fcoe: precedence bug in fcoe_filter_frames() [SCSI] libfcoe: Remove stale fcoe-netdev entries [SCSI] libfcoe: Move FCOE_MTU definition from fcoe.h to libfcoe.h [SCSI] libfc: introduce __fc_fill_fc_hdr that accepts fc_hdr as an argument [SCSI] fcoe, libfc: initialize EM anchors list and then update npiv EMs [SCSI] Revert "[SCSI] libfc: fix exchange being deleted when the abort itself is timed out" [SCSI] libfc: Fixing a memory leak when destroying an interface [SCSI] megaraid_sas: Version and Changelog update ... Fix up trivial conflicts due to whitespace differences in drivers/scsi/libsas/{sas_ata.c,sas_scsi_host.c}
2011-03-17cfq-iosched: Don't update group weights when on service treeJustin TerAvest
Version 3 is updated to apply to for-2.6.39/core. For version 2, I took Vivek's advice and made sure we update the group weight from cfq_group_service_tree_add(). If a weight was updated while a group is on the service tree, the calculation for the total weight of the service tree can be adjusted improperly, which either leads to bad service tree weights, or potentially crashes (if total_weight becomes 0). This patch defers updates to the weight until a group is off the service tree. Signed-off-by: Justin TerAvest <teravest@google.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-12blk-cgroup: Add unaccounted time to timeslice_used.Justin TerAvest
There are two kind of times that tasks are not charged for: the first seek and the extra time slice used over the allocated timeslice. Both of these exported as a new unaccounted_time stat. I think it would be good to have this reported in 'time' as well, but that is probably a separate discussion. Signed-off-by: Justin TerAvest <teravest@google.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-11block: remove obsolete comments for blkdev_issue_zeroout.Tao Ma
barrier is already removed, so remove the obsolete comments in blkdev_issue_zeroout. Cc: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Tao Ma <boyu.mt@taobao.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-11block: fix mis-synchronisation in blkdev_issue_zeroout()Lukas Czerner
BZ29402 https://bugzilla.kernel.org/show_bug.cgi?id=29402 We can hit serious mis-synchronization in bio completion path of blkdev_issue_zeroout() leading to a panic. The problem is that when we are going to wait_for_completion() in blkdev_issue_zeroout() we check if the bb.done equals issued (number of submitted bios). If it does, we can skip the wait_for_completition() and just out of the function since there is nothing to wait for. However, there is a ordering problem because bio_batch_end_io() is calling atomic_inc(&bb->done) before complete(), hence it might seem to blkdev_issue_zeroout() that all bios has been completed and exit. At this point when bio_batch_end_io() is going to call complete(bb->wait), bb and wait does not longer exist since it was allocated on stack in blkdev_issue_zeroout() ==> panic! (thread 1) (thread 2) bio_batch_end_io() blkdev_issue_zeroout() if(bb) { ... if (bb->end_io) ... bb->end_io(bio, err); ... atomic_inc(&bb->done); ... ... while (issued != atomic_read(&bb.done)) ... (let issued == bb.done) ... (do the rest of the function) ... return ret; complete(bb->wait); ^^^^^^^^ panic We can fix this easily by simplifying bio_batch and completion counting. Also remove bio_end_io_t *end_io since it is not used. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Reported-by: Eric Whitney <eric.whitney@hp.com> Tested-by: Eric Whitney <eric.whitney@hp.com> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> CC: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-10Merge branch 'for-2.6.39/stack-plug' into for-2.6.39/coreJens Axboe
Conflicts: block/blk-core.c block/blk-flush.c drivers/md/raid1.c drivers/md/raid10.c drivers/md/raid5.c fs/nilfs2/btnode.c fs/nilfs2/mdt.c Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-10blk-throttle: Use blk_plug in throttle dispatchVivek Goyal
Use plug in throttle dispatch also as we are dispatching a bunch of bios in throttle context and some of them might merge. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-10block: kill off REQ_UNPLUGJens Axboe
With the plugging now being explicitly controlled by the submitter, callers need not pass down unplugging hints to the block layer. If they want to unplug, it's because they manually plugged on their own - in which case, they should just unplug at will. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-10block: remove per-queue pluggingJens Axboe
Code has been converted over to the new explicit on-stack plugging, and delay users have been converted to use the new API for that. So lets kill off the old plugging along with aops->sync_page(). Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-10block: initial patch for on-stack per-task pluggingJens Axboe
This patch adds support for creating a queuing context outside of the queue itself. This enables us to batch up pieces of IO before grabbing the block device queue lock and submitting them to the IO scheduler. The context is created on the stack of the process and assigned in the task structure, so that we can auto-unplug it if we hit a schedule event. The current queue plugging happens implicitly if IO is submitted to an empty device, yet callers have to remember to unplug that IO when they are going to wait for it. This is an ugly API and has caused bugs in the past. Additionally, it requires hacks in the vm (->sync_page() callback) to handle that logic. By switching to an explicit plugging scheme we make the API a lot nicer and can get rid of the ->sync_page() hack in the vm. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-10block: add API for delaying work/request_fn a little bitJens Axboe
Currently we use plugging for that, but as plugging is going away, we need an alternative mechanism. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-09block: Don't implicitly trigger event check on disk_unblock_events()Tejun Heo
Currently, disk_unblock_events() implicitly kick event check if the block count reaches zero. This behavior is not described in the comment and hinders with future changes. Make the unblocker explicitly check events by calling disk_check_events() as necessary. This patch doesn't cause any behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Kay Sievers <kay.sievers@vrfy.org>
2011-03-08blk-cgroup: Lower minimum weight from 100 to 10.Justin TerAvest
We've found that we still get good, useful isolation at weights this low. I'd like to adjust the minimum so that any other changes can take these values into account. Signed-off-by: Justin TerAvest <teravest@google.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-07blk-throttle: Some cleanups and race fixes in limit update codeVivek Goyal
When throttle group limits are updated through cgroups, a thread is woken up to process these updates. While reviewing that code, oleg noted couple of race conditions existed in the code and he also suggested that code can be simplified. This patch fixes the races simplifies the code based on Oleg's suggestions: - Use xchg(). - Introduced a common function throtl_update_blkio_group_common() which is shared now by all iops/bps update functions. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Fixed a merge issue, throtl_schedule_delayed_work() takes throtl_data as the argument now, not the queue. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-07blk-throttle: process limit change only through one functionVivek Goyal
With the help of cgroup interface one can go and upate the bps/iops limits of existing group. Once the limits are udpated, a thread is woken up to see if some blocked group needs recalculation based on new limits and needs to be requeued. There was also a piece of code where I was checking for group limit update when a fresh bio comes in. This patch gets rid of that piece of code and keeps processing the limit change at one place throtl_process_limit_change(). It just keeps the code simple and easy to understand. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-07Merge branch 'block-for-2.6.39-core' of ↵Jens Axboe
ssh://master.kernel.org/pub/scm/linux/kernel/git/tj/misc into for-2.6.39/core
2011-03-07cfq-iosched: Fix update_vdisktime logicGui Jianfeng
The update_vdisktime logic is broken since commit b54ce60eb7f61f8e314b8b241b0469eda3bb1d42, st->min_vdisktime never makes a progress. Fix it. Thanks Vivek for pointing it out. Signed-off-by: Gui Jianfeng <guijianfen@cn.fujitsu.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-07cfq-iosched: give busy sync queue no dispatch limitShaohua Li
If there are a sync and an async queue and the sync queue's think time is small, we can ignore the sync queue's dispatch quantum. Because the sync queue will always preempt the async queue, we don't need to care about async's latency. This can fix a performance regression of aiostress test, which is introduced by commit f8ae6e3eb825. The issue should exist even without the commit, but the commit amplifies the impact. The initial post does the same optimization for RT queue too, but since I have no real workload for it, Vivek suggests to drop it. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Reviewed-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-07cfq-iosched: fix race in cfq_set_request()Jens Axboe
We need to hold the queue lock over the reference increment, it's not atomic anymore. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-04Merge branch 'for-linus' of ../linux-2.6-block into block-for-2.6.39/coreTejun Heo
This merge creates two set of conflicts. One is simple context conflicts caused by removal of throtl_scheduled_delayed_work() in for-linus and removal of throtl_shutdown_timer_wq() in for-2.6.39/core. The other is caused by commit 255bb490c8 (block: blk-flush shouldn't call directly into q->request_fn() __blk_run_queue()) in for-linus crashing with FLUSH reimplementation in for-2.6.39/core. The conflict isn't trivial but the resolution is straight-forward. * __blk_run_queue() calls in flush_end_io() and flush_data_end_io() should be called with @force_kblockd set to %true. * elv_insert() in blk_kick_flush() should use %ELEVATOR_INSERT_REQUEUE. Both changes are to avoid invoking ->request_fn() directly from request completion path and closely match the changes in the commit 255bb490c8. Signed-off-by: Tejun Heo <tj@kernel.org>
2011-03-02block: Move blk_throtl_exit() call to blk_cleanup_queue()Vivek Goyal
Move blk_throtl_exit() in blk_cleanup_queue() as blk_throtl_exit() is written in such a way that it needs queue lock. In blk_release_queue() there is no gurantee that ->queue_lock is still around. Initially blk_throtl_exit() was in blk_cleanup_queue() but Ingo reported one problem. https://lkml.org/lkml/2010/10/23/86 And a quick fix moved blk_throtl_exit() to blk_release_queue(). commit 7ad58c028652753814054f4e3ac58f925e7343f4 Author: Jens Axboe <jaxboe@fusionio.com> Date: Sat Oct 23 20:40:26 2010 +0200 block: fix use-after-free bug in blk throttle code This patch reverts above change and does not try to shutdown the throtl work in blk_sync_queue(). By avoiding call to throtl_shutdown_timer_wq() from blk_sync_queue(), we should also avoid the problem reported by Ingo. blk_sync_queue() seems to be used only by md driver and it seems to be using it to make sure q->unplug_fn is not called as md registers its own unplug functions and it is about to free up the data structures used by unplug_fn(). Block throttle does not call back into unplug_fn() or into md. So there is no need to cancel blk throttle work. In fact I think cancelling block throttle work is bad because it might happen that some bios are throttled and scheduled to be dispatched later with the help of pending work and if work is cancelled, these bios might never be dispatched. Block layer also uses blk_sync_queue() during blk_cleanup_queue() and blk_release_queue() time. That should be safe as we are also calling blk_throtl_exit() which should make sure all the throttling related data structures are cleaned up. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-02block: Initialize ->queue_lock to internal lock at queue allocation timeVivek Goyal
There does not seem to be a clear convention whether q->queue_lock is initialized or not when blk_cleanup_queue() is called. In the past it was not necessary but now blk_throtl_exit() takes up queue lock by default and needs queue lock to be available. In fact elevator_exit() code also has similar requirement just that it is less stringent in the sense that elevator_exit() is called only if elevator is initialized. Two problems have been noticed because of ambiguity about spin lock status. - If a driver calls blk_alloc_queue() and then soon calls blk_cleanup_queue() almost immediately, (because some other driver structure allocation failed or some other error happened) then blk_throtl_exit() will run into issues as queue lock is not initialized. Loop driver ran into this issue recently and I noticed error paths in md driver too. Similar error paths should exist in other drivers too. - If some driver provided external spin lock and zapped the lock before blk_cleanup_queue(), then it can lead to issues. So this patch initializes the default queue lock at queue allocation time. block throttling code is one of the users of queue lock and it is initialized at the queue allocation time, so it makes sense to initialize ->queue_lock also to internal lock. A driver can overide that lock later. This will take care of the issue where a driver does not have to worry about initializing the queue lock to default before calling blk_cleanup_queue() Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-02block/genhd: Change some numerals into macrosLiu Yuan
Rename the numerals in the diskstats_show() into the macros. Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Liu Yuan <tailai.ly@taobao.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-02block: blk-flush shouldn't call directly into q->request_fn() __blk_run_queue()Tejun Heo
blk-flush decomposes a flush into sequence of multiple requests. On completion of a request, the next one is queued; however, block layer must not implicitly call into q->request_fn() directly from completion path. This makes the queue behave unexpectedly when seen from the drivers and violates the assumption that q->request_fn() is called with process context + queue_lock. This patch makes blk-flush the following two changes to make sure q->request_fn() is not called directly from request completion path. - blk_flush_complete_seq_end_io() now asks __blk_run_queue() to always use kblockd instead of calling directly into q->request_fn(). - queue_next_fseq() uses ELEVATOR_INSERT_REQUEUE instead of ELEVATOR_INSERT_FRONT so that elv_insert() doesn't try to unplug the request queue directly. Reported by Jan in the following threads. http://thread.gmane.org/gmane.linux.ide/48778 http://thread.gmane.org/gmane.linux.ide/48786 stable: applicable to v2.6.37. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Jan Beulich <JBeulich@novell.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: stable@kernel.org Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-02block: add @force_kblockd to __blk_run_queue()Tejun Heo
__blk_run_queue() automatically either calls q->request_fn() directly or schedules kblockd depending on whether the function is recursed. blk-flush implementation needs to be able to explicitly choose kblockd. Add @force_kblockd. All the current users are converted to specify %false for the parameter and this patch doesn't introduce any behavior change. stable: This is prerequisite for fixing ide oops caused by the new blk-flush implementation. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jan Beulich <JBeulich@novell.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: stable@kernel.org Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-01cfq-iosched: Always provide group isolation.Justin TerAvest
Effectively, make group_isolation=1 the default and remove the tunable. The setting group_isolation=0 was because by default we idle on sync-noidle tree and on fast devices, this can be very harmful for throughput. However, this problem can also be addressed by tuning slice_idle and possibly group_idle on faster storage devices. This change simplifies the CFQ code by removing the feature entirely. Signed-off-by: Justin TerAvest <teravest@google.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-01Merge commit 'v2.6.38-rc6' into for-2.6.39/coreJens Axboe
Conflicts: block/cfq-iosched.c Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-01block: fix kernel-doc format for blkdev_issue_zerooutBen Hutchings
Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-01blk-throttle: Do not use kblockd workqueue for throtl workVivek Goyal
o Dominik Klein reported a system hang issue while doing some blkio throttling testing. https://lkml.org/lkml/2011/2/24/173 o Some tracing revealed that CFQ was not dispatching any more jobs as queue unplug was not happening. And queue unplug was not happening because unplug work was not being called as there was one throttling work on same cpu which as not finished yet. And throttling work had not finished as it was tyring to dispatch a bio to CFQ but all the request descriptors were consume to it was put to sleep. o So basically it is a cyclic dependecny between CFQ unplug work and throtl dispatch work. Tejun suggested that use separate workqueue for such cases. o This patch uses a separate workqueue for throttle related work and does not rely on kblockd workqueue anymore. Cc: stable@kernel.org Reported-by: Dominik Klein <dk@in-telegence.net> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-02-25Merge branch 'for-linus' of git://neil.brown.name/mdLinus Torvalds
* 'for-linus' of git://neil.brown.name/md: md: Fix - again - partition detection when array becomes active Fix over-zealous flush_disk when changing device size. md: avoid spinlock problem in blk_throtl_exit md: correctly handle probe of an 'mdp' device. md: don't set_capacity before array is active. md: Fix raid1->raid0 takeover
2011-02-24block: fix refcounting in BLKBSZSETMiklos Szeredi
Adam Kovari and others reported that disconnecting an USB drive with an ntfs-3g filesystem would cause "kernel BUG at fs/inode.c:1421!" to be triggered. The BUG could be traced back to ioctl(BLKBSZSET), which would erroneously decrement the refcount on the bdev. This is because blkdev_get() expects the refcount to be already incremented and either returns success or decrements the refcount and returns an error. The bug was introduced by e525fd89 (block: make blkdev_get/put() handle exclusive access), which didn't take into account this behavior of blkdev_get(). This fixes https://bugzilla.kernel.org/show_bug.cgi?id=29202 (and likely 29792 too) Reported-by: Adam Kovari <kovariadam@gmail.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-24Fix over-zealous flush_disk when changing device size.NeilBrown
There are two cases when we call flush_disk. In one, the device has disappeared (check_disk_change) so any data will hold becomes irrelevant. In the oter, the device has changed size (check_disk_size_change) so data we hold may be irrelevant. In both cases it makes sense to discard any 'clean' buffers, so they will be read back from the device if needed. In the former case it makes sense to discard 'dirty' buffers as there will never be anywhere safe to write the data. In the second case it *does*not* make sense to discard dirty buffers as that will lead to file system corruption when you simply enlarge the containing devices. flush_disk calls __invalidate_devices. __invalidate_device calls both invalidate_inodes and invalidate_bdev. invalidate_inodes *does* discard I_DIRTY inodes and this does lead to fs corruption. invalidate_bev *does*not* discard dirty pages, but I don't really care about that at present. So this patch adds a flag to __invalidate_device (calling it __invalidate_device2) to indicate whether dirty buffers should be killed, and this is passed to invalidate_inodes which can choose to skip dirty inodes. flusk_disk then passes true from check_disk_change and false from check_disk_size_change. dm avoids tripping over this problem by calling i_size_write directly rathher than using check_disk_size_change. md does use check_disk_size_change and so is affected. This regression was introduced by commit 608aeef17a which causes check_disk_size_change to call flush_disk, so it is suitable for any kernel since 2.6.27. Cc: stable@kernel.org Acked-by: Jeff Moyer <jmoyer@redhat.com> Cc: Andrew Patterson <andrew.patterson@hp.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: NeilBrown <neilb@suse.de>
2011-02-12[SCSI] block: improve detail in I/O error messagesHannes Reinecke
Classify severity of I/O errors for target, nexus, and transport errors. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Hannes Reinecke <hare@suse.de> Acked-by: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
2011-02-11block: share request flush fields with elevator_privateMike Snitzer
Flush requests are never put on the IO scheduler. Convert request structure's elevator_private* into an array and have the flush fields share a union with it. Reclaim the space lost in 'struct request' by moving 'completion_data' back in the union with 'rb_node'. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-02-11block: skip elevator data initialization for flush requestsMike Snitzer
Skip elevator initialization for flush requests by passing priv=0 to blk_alloc_request() in get_request(). As such elv_set_request() is never called for flush requests. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-02-09Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds
* 'for-linus' of git://git.kernel.dk/linux-2.6-block: cdrom: support devices that have check_events but not media_changed cfq-iosched: Don't wait if queue already has requests. blkio-throttle: Avoid calling blkiocg_lookup_group() for root group cfq: rename a function to give it more appropriate name cciss: make cciss_revalidate not loop through CISS_MAX_LUNS volumes unnecessarily. drivers/block/aoe/Makefile: replace the use of <module>-objs with <module>-y loop: queue_lock NULL pointer derefence in blk_throtl_exit drivers/block/Makefile: replace the use of <module>-objs with <module>-y blktrace: Don't output messages if NOTIFY isn't set.
2011-02-09cfq-iosched: Don't wait if queue already has requests.Justin TerAvest
Commit 7667aa0630407bc07dc38dcc79d29cc0a65553c1 added logic to wait for the last queue of the group to become busy (have at least one request), so that the group does not lose out for not being continuously backlogged. The commit did not check for the condition that the last queue already has some requests. As a result, if the queue already has requests, wait_busy is set. Later on, cfq_select_queue() checks the flag, and decides that since the queue has a request now and wait_busy is set, the queue is expired. This results in early expiration of the queue. This patch fixes the problem by adding a check to see if queue already has requests. If it does, wait_busy is not set. As a result, time slices do not expire early. The queues with more than one request are usually buffered writers. Testing shows improvement in isolation between buffered writers. Cc: stable@kernel.org Signed-off-by: Justin TerAvest <teravest@google.com> Reviewed-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-01-25block: reimplement FLUSH/FUA to support mergeTejun Heo
The current FLUSH/FUA support has evolved from the implementation which had to perform queue draining. As such, sequencing is done queue-wide one flush request after another. However, with the draining requirement gone, there's no reason to keep the queue-wide sequential approach. This patch reimplements FLUSH/FUA support such that each FLUSH/FUA request is sequenced individually. The actual FLUSH execution is double buffered and whenever a request wants to execute one for either PRE or POSTFLUSH, it queues on the pending queue. Once certain conditions are met, a flush request is issued and on its completion all pending requests proceed to the next sequence. This allows arbitrary merging of different type of flushes. How they are merged can be primarily controlled and tuned by adjusting the above said 'conditions' used to determine when to issue the next flush. This is inspired by Darrick's patches to merge multiple zero-data flushes which helps workloads with highly concurrent fsync requests. * As flush requests are never put on the IO scheduler, request fields used for flush share space with rq->rb_node. rq->completion_data is moved out of the union. This increases the request size by one pointer. As rq->elevator_private* are used only by the iosched too, it is possible to reduce the request size further. However, to do that, we need to modify request allocation path such that iosched data is not allocated for flush requests. * FLUSH/FUA processing happens on insertion now instead of dispatch. - Comments updated as per Vivek and Mike. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: "Darrick J. Wong" <djwong@us.ibm.com> Cc: Shaohua Li <shli@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-01-25block: improve flush bio completionTejun Heo
bio's for flush are completed twice - once during the data phase and one more time after the whole sequence is complete. The first completion shouldn't notify completion to the issuer. This was achieved by skipping all bio completion steps in req_bio_endio() for the first completion; however, this has two drawbacks. * Error is not recorded in bio and must be tracked somewhere else. * Partial completion is not supported. Both don't cause problems for the current users; however, they make further improvements difficult. Change req_bio_endio() such that it only skips the actual notification part for the first completion. bio completion is implemented with partial completions on mind anyway so this is as simple as moving the REQ_FLUSH_SEQ conditional such that only calling of bio_endio() is skipped. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-01-25block: add REQ_FLUSH_SEQTejun Heo
rq == &q->flush_rq was used to determine whether a rq is part of a flush sequence, which worked because all requests in a flush sequence were sequenced using the single dedicated request. This is about to change, so introduce REQ_FLUSH_SEQ flag to distinguish flush sequence requests. This patch doesn't cause any behavior change. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-01-20kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERTDavid Rientjes
The meaning of CONFIG_EMBEDDED has long since been obsoleted; the option is used to configure any non-standard kernel with a much larger scope than only small devices. This patch renames the option to CONFIG_EXPERT in init/Kconfig and fixes references to the option throughout the kernel. A new CONFIG_EMBEDDED option is added that automatically selects CONFIG_EXPERT when enabled and can be used in the future to isolate options that should only be considered for embedded systems (RISC architectures, SLOB, etc). Calling the option "EXPERT" more accurately represents its intention: only expert users who understand the impact of the configuration changes they are making should enable it. Reviewed-by: Ingo Molnar <mingo@elte.hu> Acked-by: David Woodhouse <david.woodhouse@intel.com> Signed-off-by: David Rientjes <rientjes@google.com> Cc: Greg KH <gregkh@suse.de> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jens Axboe <axboe@kernel.dk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Robin Holt <holt@sgi.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>