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* Merge tag 'dm-3.20-changes' of ↵Linus Torvalds2015-02-1315-193/+407
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm Pull device mapper changes from Mike Snitzer: - The most significant change this cycle is request-based DM now supports stacking ontop of blk-mq devices. This blk-mq support changes the model request-based DM uses for cloning a request to relying on calling blk_get_request() directly from the underlying blk-mq device. An early consumer of this code is Intel's emerging NVMe hardware; thanks to Keith Busch for working on, and pushing for, these changes. - A few other small fixes and cleanups across other DM targets. * tag 'dm-3.20-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dm: inherit QUEUE_FLAG_SG_GAPS flags from underlying queues dm snapshot: remove unnecessary NULL checks before vfree() calls dm mpath: simplify failure path of dm_multipath_init() dm thin metadata: remove unused dm_pool_get_data_block_size() dm ioctl: fix stale comment above dm_get_inactive_table() dm crypt: update url in CONFIG_DM_CRYPT help text dm bufio: fix time comparison to use time_after_eq() dm: use time_in_range() and time_after() dm raid: fix a couple integer overflows dm table: train hybrid target type detection to select blk-mq if appropriate dm: allocate requests in target when stacking on blk-mq devices dm: prepare for allocating blk-mq clone requests in target dm: submit stacked requests in irq enabled context dm: split request structure out from dm_rq_target_io structure dm: remove exports for request-based interfaces without external callers
| * dm: inherit QUEUE_FLAG_SG_GAPS flags from underlying queuesKeith Busch2015-02-111-0/+13
| | | | | | | | | | | | | | | | | | | | | | A DM device must inherit the QUEUE_FLAG_SG_GAPS flags from its underlying block devices' request queues. This fixes problems when submitting cloned requests to multipathed devices requiring virtually contiguous buffers. Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * dm snapshot: remove unnecessary NULL checks before vfree() callsMarkus Elfring2015-02-091-10/+4Star
| | | | | | | | | | | | | | | | | | | | The vfree() function performs input parameter validation. Thus the NULL pointer test around vfree() calls is not needed. This issue was detected by using the Coccinelle software. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * dm mpath: simplify failure path of dm_multipath_init()Johannes Thumshirn2015-02-091-9/+15
| | | | | | | | | | | | | | | | Currently the cleanup of all error cases are open-coded. Introduce a common exit path and labels. Signed-off-by: Johannes Thumshirn <morbidrsa@gmail.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * dm thin metadata: remove unused dm_pool_get_data_block_size()Rickard Strandqvist2015-02-092-11/+0Star
| | | | | | | | | | | | | | | | | | | | | | The thin-pool target doesn't display the data block size as part of its table status, unlike the dm-cache target, so there is no need for dm_pool_get_data_block_size(). This was found using cppcheck. Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * dm ioctl: fix stale comment above dm_get_inactive_table()Junxiao Bi2015-02-091-2/+2
| | | | | | | | | | | | | | dm_table_put() was replaced by dm_put_live_table(). Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * dm crypt: update url in CONFIG_DM_CRYPT help textLoic Pefferkorn2015-02-091-3/+2Star
| | | | | | | | | | | | | | Update the obsolete url in the CONFIG_DM_CRYPT help text. Signed-off-by: Loic Pefferkorn <loic@loicp.eu> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * dm bufio: fix time comparison to use time_after_eq()Asaf Vertz2015-02-091-1/+2
| | | | | | | | | | | | | | | | To be future-proof and for better readability the time comparison is modified to use time_after_eq() instead of plain, error-prone math. Signed-off-by: Asaf Vertz <asaf.vertz@tandemg.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * dm: use time_in_range() and time_after()Manuel Schölling2015-02-093-6/+9
| | | | | | | | | | | | | | | | To be future-proof and for better readability the time comparisons are modified to use time_in_range() and time_after() instead of plain, error-prone math. Signed-off-by: Manuel Schölling <manuel.schoelling@gmx.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * dm raid: fix a couple integer overflowsDan Carpenter2015-02-091-9/+7Star
| | | | | | | | | | | | | | | | | | | | | | | | | | My static checker complains that if "num_raid_params" is UINT_MAX then the "if (num_raid_params + 1 > argc) {" check doesn't work as intended. The other change is that I moved the "if (argc != (num_raid_devs * 2))" condition forward a few lines so it was before the call to context_alloc(). If we had an integer overflow inside that function then it would lead to an immediate crash. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * dm table: train hybrid target type detection to select blk-mq if appropriateMike Snitzer2015-02-092-16/+22
| | | | | | | | | | | | | | | | | | | | | | Otherwise replacing the multipath target with the error target fails: device-mapper: ioctl: can't change device type after initial table load. The error target was mistakenly considered to be target type DM_TYPE_REQUEST_BASED rather than DM_TYPE_MQ_REQUEST_BASED even if the target it was to replace was of type DM_TYPE_MQ_REQUEST_BASED. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * dm: allocate requests in target when stacking on blk-mq devicesMike Snitzer2015-02-095-46/+176
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For blk-mq request-based DM the responsibility of allocating a cloned request is transfered from DM core to the target type. Doing so enables the cloned request to be allocated from the appropriate blk-mq request_queue's pool (only the DM target, e.g. multipath, can know which block device to send a given cloned request to). Care was taken to preserve compatibility with old-style block request completion that requires request-based DM _not_ acquire the clone request's queue lock in the completion path. As such, there are now 2 different request-based DM target_type interfaces: 1) the original .map_rq() interface will continue to be used for non-blk-mq devices -- the preallocated clone request is passed in from DM core. 2) a new .clone_and_map_rq() and .release_clone_rq() will be used for blk-mq devices -- blk_get_request() and blk_put_request() are used respectively from these hooks. dm_table_set_type() was updated to detect if the request-based target is being stacked on blk-mq devices, if so DM_TYPE_MQ_REQUEST_BASED is set. DM core disallows switching the DM table's type after it is set. This means that there is no mixing of non-blk-mq and blk-mq devices within the same request-based DM table. [This patch was started by Keith and later heavily modified by Mike] Tested-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * dm: prepare for allocating blk-mq clone requests in targetKeith Busch2015-02-091-68/+66Star
| | | | | | | | | | | | | | | | | | | | | | | | For blk-mq request-based DM the responsibility of allocating a cloned request will be transfered from DM core to the target type. To prepare for conditionally using this new model the original request's 'special' now points to the dm_rq_target_io because the clone is allocated later in the block layer rather than in DM core. Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * dm: submit stacked requests in irq enabled contextKeith Busch2015-02-092-18/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Switch to having request-based DM enqueue all prep'ed requests into work processed by another thread. This allows request-based DM to invoke block APIs that assume interrupt enabled context (e.g. blk_get_request) and is a prerequisite for adding blk-mq support to request-based DM. The new kernel thread is only initialized for request-based DM devices. multipath_map() is now always in irq enabled context so change multipath spinlock (m->lock) locking to always disable interrupts. Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * dm: split request structure out from dm_rq_target_io structureMike Snitzer2015-02-091-9/+61
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Request-based DM support for blk-mq devices requires that dm_rq_target_io structures not be allocated with an embedded request structure. The request-based DM target (e.g. dm-multipath) must allocate the request from the blk-mq devices' request_queue using blk_get_request(). The unfortunate side-effect of this change is old-style request-based DM support will no longer use contiguous memory for the dm_rq_target_io and request structures for each clone. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * dm: remove exports for request-based interfaces without external callersMike Snitzer2015-02-091-6/+3Star
| | | | | | | | | | | | | | Remove exports for dm_dispatch_request, dm_requeue_unmapped_request, and dm_kill_unmapped_request. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* | Merge branch 'for-3.20/core' of git://git.kernel.dk/linux-blockLinus Torvalds2015-02-121-0/+1
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull core block IO changes from Jens Axboe: "This contains: - A series from Christoph that cleans up and refactors various parts of the REQ_BLOCK_PC handling. Contributions in that series from Dongsu Park and Kent Overstreet as well. - CFQ: - A bug fix for cfq for realtime IO scheduling from Jeff Moyer. - A stable patch fixing a potential crash in CFQ in OOM situations. From Konstantin Khlebnikov. - blk-mq: - Add support for tag allocation policies, from Shaohua. This is a prep patch enabling libata (and other SCSI parts) to use the blk-mq tagging, instead of rolling their own. - Various little tweaks from Keith and Mike, in preparation for DM blk-mq support. - Minor little fixes or tweaks from me. - A double free error fix from Tony Battersby. - The partition 4k issue fixes from Matthew and Boaz. - Add support for zero+unprovision for blkdev_issue_zeroout() from Martin" * 'for-3.20/core' of git://git.kernel.dk/linux-block: (27 commits) block: remove unused function blk_bio_map_sg block: handle the null_mapped flag correctly in blk_rq_map_user_iov blk-mq: fix double-free in error path block: prevent request-to-request merging with gaps if not allowed blk-mq: make blk_mq_run_queues() static dm: fix multipath regression due to initializing wrong request cfq-iosched: handle failure of cfq group allocation block: Quiesce zeroout wrapper block: rewrite and split __bio_copy_iov() block: merge __bio_map_user_iov into bio_map_user_iov block: merge __bio_map_kern into bio_map_kern block: pass iov_iter to the BLOCK_PC mapping functions block: add a helper to free bio bounce buffer pages block: use blk_rq_map_user_iov to implement blk_rq_map_user block: simplify bio_map_kern block: mark blk-mq devices as stackable block: keep established cmd_flags when cloning into a blk-mq request block: add blk-mq support to blk_insert_cloned_request() block: require blk_rq_prep_clone() be given an initialized clone request blk-mq: add tag allocation policy ...
| * dm: fix multipath regression due to initializing wrong requestMike Snitzer2015-02-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | Commit febf715 ("block: require blk_rq_prep_clone() be given an initialized clone request") introduced a regression by calling blk_rq_init() on the original request rather than the clone request that is passed to setup_clone(). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Fixes: febf71588c2a ("block: require blk_rq_prep_clone() be given an initialized clone request") Signed-off-by: Jens Axboe <axboe@fb.com>
| * block: require blk_rq_prep_clone() be given an initialized clone requestKeith Busch2015-01-281-0/+1
| | | | | | | | | | | | | | | | | | | | Prepare to allow blk_rq_prep_clone() to accept clone requests that were allocated from blk-mq request queues. As such the blk_rq_prep_clone() caller must first initialize the clone request. Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* | Merge tag 'md/3.20' of git://neil.brown.name/mdLinus Torvalds2015-02-1214-606/+858
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull md updates from Neil Brown: - assorted locking changes so that access to /proc/mdstat and much of /sys/block/mdXX/md/* is protected by a spinlock rather than a mutex and will never block indefinitely. - Make an 'if' condition in RAID5 - which has been implicated in recent bugs - more readable. - misc minor fixes * tag 'md/3.20' of git://neil.brown.name/md: (28 commits) md/raid10: fix conversion from RAID0 to RAID10 md: wakeup thread upon rdev_dec_pending() md: make reconfig_mutex optional for writes to md sysfs files. md: move mddev_lock and related to md.h md: use mddev->lock to protect updates to resync_{min,max}. md: minor cleanup in safe_delay_store. md: move GET_BITMAP_FILE ioctl out from mddev_lock. md: tidy up set_bitmap_file md: remove unnecessary 'buf' from get_bitmap_file. md: remove mddev_lock from rdev_attr_show() md: remove mddev_lock() from md_attr_show() md/raid5: use ->lock to protect accessing raid5 sysfs attributes. md: remove need for mddev_lock() in md_seq_show() md/bitmap: protect clearing of ->bitmap by mddev->lock md: protect ->pers changes with mddev->lock md: level_store: group all important changes into one place. md: rename ->stop to ->free md: split detach operation out from ->stop. md/linear: remove rcu protections in favour of suspend/resume md: make merge_bvec_fn more robust in face of personality changes. ...
| * | md/raid10: fix conversion from RAID0 to RAID10NeilBrown2015-02-121-3/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A RAID0 array (like a LINEAR array) does not have a concept of 'size' being the amount of each device that is in use. Rather, as much of each device as is available is used. So the 'size' is set to 0 and ignored. RAID10 does have this concept and needs it to be set correctly. So when we convert RAID0 to RAID10 we must determine the 'size' (that being the size of the first 'strip_zone' in the RAID0), and set it correctly. Reported-and-tested-by: Xiao Ni <xni@redhat.com> Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: wakeup thread upon rdev_dec_pending()Hannes Reinecke2015-02-051-7/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | After each call to rdev_dec_pending() we should wakeup the md thread if the device is found to be faulty. Otherwise we'll incur heavy delays on failing devices. Signed-off-by: Neil Brown <nfbrown@suse.de> Signed-off-by: Hannes Reinecke <hare@suse.de>
| * | md: make reconfig_mutex optional for writes to md sysfs files.NeilBrown2015-02-052-164/+316
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rather than using mddev_lock() to take the reconfig_mutex when writing to any md sysfs file, we only take mddev_lock() in the particular _store() functions that require it. Admittedly this is most, but it isn't all. This also allows us to remove special-case handling for new_dev_store (in md_attr_store). Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: move mddev_lock and related to md.hNeilBrown2015-02-052-24/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | The one which is not inline (mddev_unlock) gets EXPORTed. This makes the locking available to personality modules so that it doesn't have to be imposed upon them. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: use mddev->lock to protect updates to resync_{min,max}.NeilBrown2015-02-052-13/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are interdependencies between these two sysfs attributes and whether a resync is currently running. Rather than depending on reconfig_mutex to ensure no races when testing these interdependencies are met, use the spinlock. This will allow the mutex to be remove from protecting this code in a subsequent patch. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: minor cleanup in safe_delay_store.NeilBrown2015-02-051-5/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There isn't really much room for races with ->safemode_delay. But as I am trying to clean up any racy code and will soon be removing reconfig_mutex protection from most _store() functions: - only set mddev->safemode_delay once, to ensure no code can see an intermediate value - use safemode_timer to call md_safemode_timeout() rather than calling it directly, to ensure it never races with itself. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: move GET_BITMAP_FILE ioctl out from mddev_lock.NeilBrown2015-02-052-26/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It makes more sense to report bitmap_info->file, rather than bitmap->file (the later is only available once the array is active). With that change, use mddev->lock to protect bitmap_info being set to NULL, and we can call get_bitmap_file() without taking the mutex. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: tidy up set_bitmap_fileNeilBrown2015-02-051-7/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | 1/ delay setting mddev->bitmap_info.file until 'f' looks usable, so we don't have to unset it. 2/ Don't allow bitmap file to be set if bitmap_info.file is already set. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: remove unnecessary 'buf' from get_bitmap_file.NeilBrown2015-02-051-8/+4Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | 'buf' is only used because d_path fills from the end of the buffer instead of from the start. We don't need a separate buf to handle that, we just need to use memmove() to move the string to the start. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: remove mddev_lock from rdev_attr_show()NeilBrown2015-02-051-22/+14Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | No rdev attributes need locking for 'show', though state_show() might benefit from ensuring it sees a consistent set of flags. None even use rdev->mddev, so testing for it isn't really needed and it certainly doesn't need to be held constant. So improve state_show() and remove the locking. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: remove mddev_lock() from md_attr_show()NeilBrown2015-02-052-16/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Most attributes can be read safely without any locking. A race might lead to a slightly out-dated value, but nothing wrong. We already have locking in some places where needed. All that remains is can_clear_show(), behind_writes_used_show() and action_show() which are easily fixed. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md/raid5: use ->lock to protect accessing raid5 sysfs attributes.NeilBrown2015-02-051-16/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It is important that mddev->private isn't freed while a sysfs attribute function is accessing it. So use mddev->lock to protect the setting of ->private to NULL, and take that lock when checking ->private for NULL and de-referencing it in the sysfs access functions. This only applies to the read ('show') side of access. Write access will be handled separately. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: remove need for mddev_lock() in md_seq_show()NeilBrown2015-02-051-5/+3Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The only access in md_seq_show that could suffer from races not protected by ->lock is walking the rdev list. This can receive sufficient protection from 'rcu'. So use rdev_for_each_rcu() and get rid of mddev_lock(). Now reading /proc/mdstat will never block in md_seq_show. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md/bitmap: protect clearing of ->bitmap by mddev->lockNeilBrown2015-02-052-0/+3
| | | | | | | | | | | | | | | | | | | | | This makes it safe to inspect the struct while holding only the spinlock. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: protect ->pers changes with mddev->lockNeilBrown2015-02-032-21/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ->pers is already protected by ->reconfig_mutex, and cannot possibly change when there are threads running or outstanding IO. However there are some places where we access ->pers not in a thread or IO context, and where ->reconfig_mutex is unnecessarily heavy-weight: level_show and md_seq_show(). So protect all changes, and those accesses, with ->lock. This is a step toward taking those accesses out from under reconfig_mutex. [Fixed missing "mddev->pers" -> "pers" conversion, thanks to Dan Carpenter <dan.carpenter@oracle.com>] Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: level_store: group all important changes into one place.NeilBrown2015-02-031-30/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Gather all the changes that can happen atomically and might be relevant to other code into one place. This will make it easier to refine the locking. Note that this puts quite a few things between mddev_detach() and ->free(). Enabling this was the point of some recent patches. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: rename ->stop to ->freeNeilBrown2015-02-039-50/+35Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that the ->stop function only frees the private data, rename is accordingly. Also pass in the private pointer as an arg rather than using mddev->private. This flexibility will be useful in level_store(). Finally, don't clear ->private. It doesn't make sense to clear it seeing that isn't what we free, and it is no longer necessary to clear ->private (it was some time ago before ->to_remove was introduced). Setting ->to_remove in ->free() is a bit of a wart, but not a big problem at the moment. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: split detach operation out from ->stop.NeilBrown2015-02-037-32/+29Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Each md personality has a 'stop' operation which does two things: 1/ it finalizes some aspects of the array to ensure nothing is accessing the ->private data 2/ it frees the ->private data. All the steps in '1' can apply to all arrays and so can be performed in common code. This is useful as in the case where we change the personality which manages an array (in level_store()), it would be helpful to do step 1 early, and step 2 later. So split the 'step 1' functionality out into a new mddev_detach(). Signed-off-by: NeilBrown <neilb@suse.de>
| * | md/linear: remove rcu protections in favour of suspend/resumeNeilBrown2015-02-031-30/+14Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The use of 'rcu' to protect accesses to ->private_data so that the ->private_data could be updated predates the introduction of mddev_suspend/mddev_resume. These are a cleaner mechanism for providing stability while swapping in a new ->private data - it is used by level_store() to support changing of raid levels. So get rid of the RCU stuff and just use mddev_suspend, mddev_resume. As these function call ->quiesce(), we add an empty function for linear just like for raid0. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: make merge_bvec_fn more robust in face of personality changes.NeilBrown2015-02-037-20/+42
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is no locking around calls to merge_bvec_fn(), so it is possible that calls which coincide with a level (or personality) change could go wrong. So create a central dispatch point for these functions and use rcu_read_lock(). If the array is suspended, reject any merge that can be rejected. If not, we know it is safe to call the function. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: make ->congested robust against personality changes.NeilBrown2015-02-0312-77/+38Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is currently no locking around calls to the 'congested' bdi function. If called at an awkward time while an array is being converted from one level (or personality) to another, there is a tiny chance of running code in an unreferenced module etc. So add a 'congested' function to the md_personality operations structure, and call it with appropriate locking from a central 'mddev_congested'. When the array personality is changing the array will be 'suspended' so no IO is processed. If mddev_congested detects this, it simply reports that the array is congested, which is a safe guess. As mddev_suspend calls synchronize_rcu(), mddev_congested can avoid races by included the whole call inside an rcu_read_lock() region. This require that the congested functions for all subordinate devices can be run under rcu_lock. Fortunately this is the case. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: rename mddev->write_lock to mddev->lockNeilBrown2015-02-032-19/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This lock is used for (slightly) more than helping with writing superblocks, and it will soon be extended further. So the name is inappropriate. Also, the _irq variant hasn't been needed since 2.6.37 as it is never taking from interrupt or bh context. So: -rename write_lock to lock -document what it protects -remove _irq ... except in md_flush_request() as there is no wait_event_lock() (with no _irq). This can be cleaned up after appropriate changes to wait.h. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md/raid5: need_this_block: tidy/fix last condition.NeilBrown2015-02-031-10/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | That last condition is unclear and over cautious. There are two related issues here. If a partial write is destined for a missing device, then either RMW or RCW can work. We must read all the available block. Only then can the missing blocks be calculated, and then the parity update performed. If RMW is not an option, then there is a complication even without partial writes. If we would need to read a missing device to perform the reconstruction, then we must first read every block so the missing device data can be computed. This is the case for RAID6 (Which currently does not support RMW) and for times when we don't trust the parity (after a crash) and so are in the process of resyncing it. So make these two cases more clear and separate, and perform the relevant tests more thoroughly. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md/raid5: need_this_block: start simplifying the last two conditions.NeilBrown2015-02-031-5/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | Both the last two cases are only relevant if something has failed and something needs to be written (but not over-written), and if it is OK to pre-read blocks at this point. So factor out those tests and explain them. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md/raid5: separate out the easy conditions in need_this_block.NeilBrown2015-02-031-9/+29
| | | | | | | | | | | | | | | | | | | | | Some of the conditions in need_this_block have very straight forward motivation. Separate those out and document them. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md/raid5: separate large if clause out of fetch_block().NeilBrown2015-02-031-4/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | fetch_block() has a very large and hard to read 'if' condition. Separate it into its own function so that it can be made more readable. Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: do_release_stripe(): No need to call md_wakeup_thread() twiceJes Sorensen2015-02-031-5/+2Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 67f455486d2ea20b2d94d6adf5b9b783d079e321 introduced a call to md_wakeup_thread() when adding to the delayed_list. However the md thread is woken up unconditionally just below. Remove the unnecessary wakeup call. Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com> Signed-off-by: NeilBrown <neilb@suse.de>
* | | Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds2015-02-091-0/+1
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU updates from Ingo Molnar: "The main RCU changes in this cycle are: - Documentation updates. - Miscellaneous fixes. - Preemptible-RCU fixes, including fixing an old bug in the interaction of RCU priority boosting and CPU hotplug. - SRCU updates. - RCU CPU stall-warning updates. - RCU torture-test updates" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits) rcu: Initialize tiny RCU stall-warning timeouts at boot rcu: Fix RCU CPU stall detection in tiny implementation rcu: Add GP-kthread-starvation checks to CPU stall warnings rcu: Make cond_resched_rcu_qs() apply to normal RCU flavors rcu: Optionally run grace-period kthreads at real-time priority ksoftirqd: Use new cond_resched_rcu_qs() function ksoftirqd: Enable IRQs and call cond_resched() before poking RCU rcutorture: Add more diagnostics in rcu_barrier() test failure case torture: Flag console.log file to prevent holdovers from earlier runs torture: Add "-enable-kvm -soundhw pcspk" to qemu command line rcutorture: Handle different mpstat versions rcutorture: Check from beginning to end of grace period rcu: Remove redundant rcu_batches_completed() declaration rcutorture: Drop rcu_torture_completed() and friends rcu: Provide rcu_batches_completed_sched() for TINY_RCU rcutorture: Use unsigned for Reader Batch computations rcutorture: Make build-output parsing correctly flag RCU's warnings rcu: Make _batches_completed() functions return unsigned long rcutorture: Issue warnings on close calls due to Reader Batch blows documentation: Fix smp typo in memory-barriers.txt ...
| * \ \ Merge branch 'for-mingo' of ↵Ingo Molnar2015-01-211-0/+1
| |\ \ \ | | |_|/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull RCU updates from Paul E. McKenney: - Documentation updates. - Miscellaneous fixes. - Preemptible-RCU fixes, including fixing an old bug in the interaction of RCU priority boosting and CPU hotplug. - SRCU updates. - RCU CPU stall-warning updates. - RCU torture-test updates. Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | rcu: Make SRCU optional by using CONFIG_SRCUPranith Kumar2015-01-061-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | SRCU is not necessary to be compiled by default in all cases. For tinification efforts not compiling SRCU unless necessary is desirable. The current patch tries to make compiling SRCU optional by introducing a new Kconfig option CONFIG_SRCU which is selected when any of the components making use of SRCU are selected. If we do not select CONFIG_SRCU, srcu.o will not be compiled at all. text data bss dec hex filename 2007 0 0 2007 7d7 kernel/rcu/srcu.o Size of arch/powerpc/boot/zImage changes from text data bss dec hex filename 831552 64180 23944 919676 e087c arch/powerpc/boot/zImage : before 829504 64180 23952 917636 e0084 arch/powerpc/boot/zImage : after so the savings are about ~2000 bytes. Signed-off-by: Pranith Kumar <bobby.prani@gmail.com> CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com> CC: Josh Triplett <josh@joshtriplett.org> CC: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> [ paulmck: resolve conflict due to removal of arch/ia64/kvm/Kconfig. ]
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