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* md: provide generic support for handling unplug callbacks.NeilBrown2011-04-181-0/+4
| | | | | | | | | | | | | When an md device adds a request to a queue, it can call mddev_check_plugged. If this succeeds then we know that the md thread will be woken up shortly, and ->plug_cnt will be non-zero until then, so some processing can be delayed. If it fails, then no unplug callback is expected and the make_request function needs to do whatever is required to make the request happen. Signed-off-by: NeilBrown <neilb@suse.de>
* md - remove old plugging code.NeilBrown2011-04-181-22/+0
| | | | | | | | | | | | | md has some plugging infrastructure for RAID5 to use because the normal plugging infrastructure required a 'request_queue', and when called from dm, RAID5 doesn't have one of those available. This relied on the ->unplug_fn callback which doesn't exist any more. So remove all of that code, both in md and raid5. Subsequent patches with restore the plugging functionality. Signed-off-by: NeilBrown <neilb@suse.de>
* Fix common misspellingsLucas De Marchi2011-03-311-1/+1
| | | | | | Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
* md: Fix - again - partition detection when array becomes activeNeilBrown2011-02-241-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Revert b821eaa572fd737faaf6928ba046e571526c36c6 and f3b99be19ded511a1bf05a148276239d9f13eefa When I wrote the first of these I had a wrong idea about the lifetime of 'struct block_device'. It can disappear at any time that the block device is not open if it falls out of the inode cache. So relying on the 'size' recorded with it to detect when the device size has changed and so we need to revalidate, is wrong. Rather, we really do need the 'changed' attribute stored directly in the mddev and set/tested as appropriate. Without this patch, a sequence of: mknod / open / close / unlink (which can cause a block_device to be created and then destroyed) will result in a rescan of the partition table and consequence removal and addition of partitions. Several of these in a row can get udev racing to create and unlink and other code can get confused. With the patch, the rescan is only performed when needed and so there are no races. This is suitable for any stable kernel from 2.6.35. Reported-by: "Wojcik, Krzysztof" <krzysztof.wojcik@intel.com> Signed-off-by: NeilBrown <neilb@suse.de> Cc: stable@kernel.org
* md: Remove the AllReserved flag for component devices.NeilBrown2011-01-311-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | This flag is not needed and is used badly. Devices that are included in a native-metadata array are reserved exclusively for that array - and currently have AllReserved set. They all are bd_claimed for the rdev and so cannot be shared. Devices that are included in external-metadata arrays can be shared among multiple arrays - providing there is no overlap. These are bd_claimed for md in general - not for a particular rdev. When changing the amount of a device that is used in an array we need to check for overlap. This currently includes a check on AllReserved So even without overlap, sharing with an AllReserved device is not allowed. However the bd_claim usage already precludes sharing with these devices, so the test on AllReserved is not needed. And in fact it is wrong. As this is the only use of AllReserved, simply remove all usage and definition of AllReserved. Signed-off-by: NeilBrown <neilb@suse.de>
* md: separate meta and data devsJonathan Brassow2011-01-141-0/+6
| | | | | | | | | | | Allow the metadata to be on a separate device from the data. This doesn't mean the data and metadata will by on separate physical devices - it simply gives device-mapper and userspace tools more flexibility. Signed-off-by: NeilBrown <neilb@suse.de>
* md-new-param-to_sync_page_ioJonathan Brassow2011-01-141-2/+2
| | | | | | | | | | Add new parameter to 'sync_page_io'. The new parameter allows us to distinguish between metadata and data operations. This becomes important later when we add the ability to use separate devices for data and metadata. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
* md: Ensure no IO request to get md device before it is properly initialised.NeilBrown2011-01-141-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | When an md device is in the process of coming on line it is possible for an IO request (typically a partition table probe) to get through before the array is fully initialised, which can cause unexpected behaviour (e.g. a crash). So explicitly record when the array is ready for IO and don't allow IO through until then. There is no possibility for a similar problem when the array is going off-line as there must only be one 'open' at that time, and it is busy off-lining the array and so cannot send IO requests. So no memory barrier is needed in md_stop() This has been a bug since commit 409c57f3801 in 2.6.30 which introduced md_make_request. Before then, each personality would register its own make_request_fn when it was ready. This is suitable for any stable kernel from 2.6.30.y onwards. Cc: <stable@kernel.org> Signed-off-by: NeilBrown <neilb@suse.de> Reported-by: "Hawrylewicz Czarnowski, Przemyslaw" <przemyslaw.hawrylewicz.czarnowski@intel.com>
* md: use separate bio pool for each md device.NeilBrown2010-10-281-0/+6
| | | | | | | | | | | | | | bio_clone and bio_alloc allocate from a common bio pool. If an md device is stacked with other devices that use this pool, or under something like swap which uses the pool, then the multiple calls on the pool can cause deadlocks. So allocate a local bio pool for each md array and use that rather than the common pool. This pool is used both for regular IO and metadata updates. Signed-off-by: NeilBrown <neilb@suse.de>
* md: change type of first arg to sync_page_io.NeilBrown2010-10-281-1/+1
| | | | | | | | | Currently sync_page_io takes a 'bdev'. Every caller passes 'rdev->bdev'. We will soon want another field out of the rdev in sync_page_io, So just pass the rdev instead of the bdev out of it. Signed-off-by: NeilBrown <neilb@suse.de>
* Merge branch 'v2.6.36-rc8' into for-2.6.37/barrierJens Axboe2010-10-191-1/+1
|\ | | | | | | | | | | | | | | | | Conflicts: block/blk-core.c drivers/block/loop.c mm/swapfile.c Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * md: resolve confusion of MD_CHANGE_CLEANNeilBrown2010-08-301-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | MD_CHANGE_CLEAN is used for two different purposes and this leads to confusion. One of the purposes is largely mirrored by MD_CHANGE_PENDING which is not used for anything else, so have MD_CHANGE_PENDING take over that purpose fully. The two purposes are: 1/ tell md_update_sb that an update is needed and that it is just a clean/dirty transition. 2/ tell user-space that an transition from clean to dirty is pending (something wants to write), and tell te kernel (by clearin the flag) that the transition is OK. The first purpose remains wit MD_CHANGE_CLEAN, the second is moved fully to MD_CHANGE_PENDING. This means that various places which conditionally set or cleared MD_CHANGE_CLEAN no longer need to be conditional. Signed-off-by: NeilBrown <neilb@suse.de>
* | md: implment REQ_FLUSH/FUA supportTejun Heo2010-09-101-17/+6
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch converts md to support REQ_FLUSH/FUA instead of now deprecated REQ_HARDBARRIER. In the core part (md.c), the following changes are notable. * Unlike REQ_HARDBARRIER, REQ_FLUSH/FUA don't interfere with processing of other requests and thus there is no reason to mark the queue congested while FLUSH/FUA is in progress. * REQ_FLUSH/FUA failures are final and its users don't need retry logic. Retry logic is removed. * Preflush needs to be issued to all member devices but FUA writes can be handled the same way as other writes - their processing can be deferred to request_queue of member devices. md_barrier_request() is renamed to md_flush_request() and simplified accordingly. For linear, raid0 and multipath, the core changes are enough. raid1, 5 and 10 need the following conversions. * raid1: Handling of FLUSH/FUA bio's can simply be deferred to request_queues of member devices. Barrier related logic removed. * raid5: Queue draining logic dropped. FUA bit is propagated through biodrain and stripe resconstruction such that all the updated parts of the stripe are written out with FUA writes if any of the dirtying writes was FUA. preread_active_stripes handling in make_request() is updated as suggested by Neil Brown. * raid10: FUA bit needs to be propagated to write clones. linear, raid0, 1, 5 and 10 tested. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Neil Brown <neilb@suse.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* Merge branch 'for-linus' of git://neil.brown.name/mdLinus Torvalds2010-08-101-1/+54
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-linus' of git://neil.brown.name/md: (24 commits) md: clean up do_md_stop md: fix another deadlock with removing sysfs attributes. md: move revalidate_disk() back outside open_mutex md/raid10: fix deadlock with unaligned read during resync md/bitmap: separate out loading a bitmap from initialising the structures. md/bitmap: prepare for storing write-intent-bitmap via dm-dirty-log. md/bitmap: optimise scanning of empty bitmaps. md/bitmap: clean up plugging calls. md/bitmap: reduce dependence on sysfs. md/bitmap: white space clean up and similar. md/raid5: export raid5 unplugging interface. md/plug: optionally use plugger to unplug an array during resync/recovery. md/raid5: add simple plugging infrastructure. md/raid5: export is_congested test raid5: Don't set read-ahead when there is no queue md: add support for raising dm events. md: export various start/stop interfaces md: split out md_rdev_init md: be more careful setting MD_CHANGE_CLEAN md/raid5: ensure we create a unique name for kmem_cache when mddev has no gendisk ...
| * md: fix another deadlock with removing sysfs attributes.NeilBrown2010-08-081-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move the deletion of sysfs attributes from reconfig_mutex to open_mutex didn't really help as a process can try to take open_mutex while holding reconfig_mutex, so the same deadlock can happen, just requiring one more process to be involved in the chain. I looks like I cannot easily use locking to wait for the sysfs deletion to complete, so don't. The only things that we cannot do while the deletions are still pending is other things which can change the sysfs namespace: run, takeover, stop. Each of these can fail with -EBUSY. So set a flag while doing a sysfs deletion, and fail run, takeover, stop if that flag is set. This is suitable for 2.6.35.x Cc: stable@kernel.org Signed-off-by: NeilBrown <neilb@suse.de>
| * md/bitmap: prepare for storing write-intent-bitmap via dm-dirty-log.NeilBrown2010-07-261-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This allows md/raid5 to fully work as a dm target. Normally md uses a 'filemap' which contains a list of pages of bits each of which may be written separately. dm-log uses and all-or-nothing approach to writing the log, so when using a dm-log, ->filemap is NULL and the flags normally stored in filemap_attr are stored in ->logattrs instead. Signed-off-by: NeilBrown <neilb@suse.de>
| * md/bitmap: clean up plugging calls.NeilBrown2010-07-261-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 1/ use md_unplug in bitmap.c as we will soon be using bitmaps under arrays with no queue attached. 2/ Don't bother plugging the queue when we set a bit in the bitmap. The reason for this was to encourage as many bits as possible to get set before we unplug and write stuff out. However every personality already plugs the queue after bitmap_startwrite either directly (raid1/raid10) or be setting STRIPE_BIT_DELAY which causes the queue to be plugged later (raid5). Signed-off-by: NeilBrown <neilb@suse.de>
| * md/bitmap: white space clean up and similar.NeilBrown2010-07-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | Fixes some whitespace problems Fixed some checkpatch.pl complaints. Replaced kmalloc ... memset(0), with kzalloc Fixed an unlikely memory leak on an error path. Reformatted a number of 'if/else' sets, sometimes replacing goto with an else clause. Removed some old comments and commented-out code. Signed-off-by: NeilBrown <neilb@suse.de>
| * md/plug: optionally use plugger to unplug an array during resync/recovery.NeilBrown2010-07-261-0/+2
| | | | | | | | | | | | | | | | | | If an array doesn't have a 'queue' then md_do_sync cannot unplug it. In that case it will have a 'plugger', so make that available to the mddev, and use it to unplug the array if needed. Signed-off-by: NeilBrown <neilb@suse.de>
| * md/raid5: add simple plugging infrastructure.NeilBrown2010-07-261-0/+20
| | | | | | | | | | | | | | | | | | | | | | md/raid5 uses the plugging infrastructure provided by the block layer and 'struct request_queue'. However when we plug raid5 under dm there is no request queue so we cannot use that. So create a similar infrastructure that is much lighter weight and use it for raid5. Signed-off-by: NeilBrown <neilb@suse.de>
| * md: add support for raising dm events.NeilBrown2010-07-261-0/+1
| | | | | | | | | | | | | | dm uses scheduled work to raise events to user-space. So allow md device to have work_structs and schedule them on an error. Signed-off-by: NeilBrown <neilb@suse.de>
| * md: export various start/stop interfacesNeilBrown2010-07-261-0/+7
| | | | | | | | | | | | | | | | | | | | export entry points for starting and stopping md arrays. This will be used by a module to make md/raid5 work under dm. Also stop calling md_stop_writes from md_stop, as that won't work well with dm - it will want to call the two separately. Signed-off-by: NeilBrown <neilb@suse.de>
| * md: split out md_rdev_initNeilBrown2010-07-261-0/+1
| | | | | | | | | | | | | | This functionality will be needed separately in a subsequent patch, so split it into it's own exported function. Signed-off-by: NeilBrown <neilb@suse.de>
| * md: reduce dependence on sysfs.NeilBrown2010-07-211-0/+12
| | | | | | | | | | | | | | We will want md devices to live as dm targets where sysfs is not visible. So allow md to not connect to sysfs. Signed-off-by: NeilBrown <neilb@suse.de>
* | block: unify flags for struct bio and struct requestChristoph Hellwig2010-08-071-2/+2
|/ | | | | | | | | | | | | | 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: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* md: fix handling of array level takeover that re-arranges devices.NeilBrown2010-06-241-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | Most array level changes leave the list of devices largely unchanged, possibly causing one at the end to become redundant. However conversions between RAID0 and RAID10 need to renumber all devices (except 0). This renumbering is currently being done in the ->run method when the new personality takes over. However this is too late as the common code in md.c might already have invalidated some of the devices if they had a ->raid_disk number that appeared to high. Moving it into the ->takeover method is too early as the array is still active at that time and wrong ->raid_disk numbers could cause confusion. So add a ->new_raid_disk field to mdk_rdev_s and use it to communicate the new raid_disk number. Now the common code knows exactly which devices need to be renumbered, and which can be invalidated, and can do it all at a convenient time when the array is suspend. It can also update some symlinks in sysfs which previously were not be updated correctly. Reported-by: Maciej Trela <maciej.trela@intel.com> Signed-off-by: NeilBrown <neilb@suse.de>
* md: simplify updating of event count to sometimes avoid updating spares.NeilBrown2010-05-181-0/+6
| | | | | | | | | | | | | | | | | | When updating the event count for a simple clean <-> dirty transition, we try to avoid updating the spares so they can safely spin-down. As the event_counts across an array must be +/- 1, this means decrementing the event_count on a dirty->clean transition. This is not always safe and we have to avoid the unsafe time. We current do this with a misguided idea about it being safe or not depending on whether the event_count is odd or even. This approach only works reliably in a few common instances, but easily falls down. So instead, simply keep internal state concerning whether it is safe or not, and always assume it is not safe when an array is first assembled. Signed-off-by: NeilBrown <neilb@suse.de>
* md: pass mddev to make_request functions rather than request_queueNeilBrown2010-05-181-1/+1
| | | | | | | | | | We used to pass the personality make_request function direct to the block layer so the first argument had to be a queue. But now we have the intermediary md_make_request so it makes at lot more sense to pass a struct mddev_s. It makes it possible to have an mddev without its own queue too. Signed-off-by: NeilBrown <neilb@suse.de>
* md: remove ->changed and related code.NeilBrown2010-05-181-1/+0
| | | | | | | | | | | We set ->changed to 1 and call check_disk_change at the end of md_open so that bd_invalidated would be set and thus partition rescan would happen appropriately. Now that we call revalidate_disk directly, which sets bd_invalidates, that indirection is no longer needed and can be removed. Signed-off-by: NeilBrown <neilb@suse.de>
* md: discard StateChanged device flag.NeilBrown2010-05-181-3/+0
| | | | | | | | This was needed when sysfs files could only be 'notified' from process context. Now that we have sys_notify_direct, we can call it directly from an interrupt. Signed-off-by: NeilBrown <neilb@suse.de>
* md: remove some dead fields from mddev_sNeilBrown2010-05-181-3/+0
| | | | | | | | | | | These fields have never been used. commit 4b6d287f627b5fb6a49f78f9e81649ff98c62bb7 added them, but also added identical files to bitmap_super_s, and only used the latter. So remove these unused fields. Signed-off-by: NeilBrown <neilb@suse.de>
* md: manage redundancy group in sysfs when changing level.NeilBrown2010-05-171-0/+1
| | | | | | | | | | | | | | | | | | | | | Some levels expect the 'redundancy group' to be present, others don't. So when we change level of an array we might need to add or remove this group. This requires fixing up the current practice of overloading ->private to indicate (when ->pers == NULL) that something needs to be removed. So create a new ->to_remove to fill that role. When changing levels, we may need to add or remove attributes. When changing RAID5 -> RAID6, we both add and remove the same thing. It is important to catch this and optimise it out as the removal is delayed until a lock is released, so trying to add immediately would cause problems. Cc: stable@kernel.org Signed-off-by: NeilBrown <neilb@suse.de>
* raid: improve MD/raid10 handling of correctable read errors.Robert Becker2009-12-141-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We've noticed severe lasting performance degradation of our raid arrays when we have drives that yield large amounts of media errors. The raid10 module will queue each failed read for retry, and also will attempt call fix_read_error() to perform the read recovery. Read recovery is performed while the array is frozen, so repeated recovery attempts can degrade the performance of the array for extended periods of time. With this patch I propose adding a per md device max number of corrected read attempts. Each rdev will maintain a count of read correction attempts in the rdev->read_errors field (not used currently for raid10). When we enter fix_read_error() we'll check to see when the last read error occurred, and divide the read error count by 2 for every hour since the last read error. If at that point our read error count exceeds the read error threshold, we'll fail the raid device. In addition in this patch I add sysfs nodes (get/set) for the per md max_read_errors attribute, the rdev->read_errors attribute, and added some printk's to indicate when fix_read_error fails to repair an rdev. For testing I used debugfs->fail_make_request to inject IO errors to the rdev while doing IO to the raid array. Signed-off-by: Robert Becker <Rob.Becker@riverbed.com> Signed-off-by: NeilBrown <neilb@suse.de>
* md: Support write-intent bitmaps with externally managed metadata.NeilBrown2009-12-141-0/+1
| | | | | | | | | | | In this case, the metadata needs to not be in the same sector as the bitmap. md will not read/write any bitmap metadata. Config must be done via sysfs and when a recovery makes the array non-degraded again, writing 'true' to 'bitmap/can_clear' will allow bits in the bitmap to be cleared again. Signed-off-by: NeilBrown <neilb@suse.de>
* md: support updating bitmap parameters via sysfs.NeilBrown2009-12-141-1/+2
| | | | | | | | | | | | | | | | | | | | A new attribute directory 'bitmap' in 'md' is created which contains files for configuring the bitmap. 'location' identifies where the bitmap is, either 'none', or 'file' or 'sector offset from metadata'. Writing 'location' can create or remove a bitmap. Adding a 'file' bitmap this way is not yet supported. 'chunksize' and 'time_base' must be set before 'location' can be set. 'chunksize' can be set before creating a bitmap, but is currently always over-ridden by the bitmap superblock. 'time_base' and 'backlog' can be updated at any time. Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Andre Noll <maan@systemlinux.org>
* md: factor out parsing of fixed-point numbersNeilBrown2009-12-141-1/+2
| | | | | | | | safe_delay_store can parse fixed point numbers (for fractions of a second). We will want to do that for another sysfs file soon, so factor out the code. Signed-off-by: NeilBrown <neilb@suse.de>
* md: support bitmap offset appropriate for external-metadata arrays.NeilBrown2009-12-141-2/+4
| | | | | | | | | | | | | For md arrays were metadata is managed externally, the kernel does not know about a superblock so the superblock offset is 0. If we want to have a write-intent-bitmap near the end of the devices of such an array, we should support sector_t sized offset. We need offset be possibly negative for when the bitmap is before the metadata, so use loff_t instead. Also add sanity check that bitmap does not overlap with data. Signed-off-by: NeilBrown <neilb@suse.de>
* md: move offset, daemon_sleep and chunksize out of bitmap structureNeilBrown2009-12-141-0/+3
| | | | | | | ... and into bitmap_info. These are all configuration parameters that need to be set before the bitmap is created. Signed-off-by: NeilBrown <neilb@suse.de>
* md: collect bitmap-specific fields into one structure.NeilBrown2009-12-141-10/+12
| | | | | | | | In preparation for making bitmap fields configurable via sysfs, start tidying up by making a single structure to contain the configuration fields. Signed-off-by: NeilBrown <neilb@suse.de>
* md: support barrier requests on all personalities.NeilBrown2009-12-141-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously barriers were only supported on RAID1. This is because other levels requires synchronisation across all devices and so needed a different approach. Here is that approach. When a barrier arrives, we send a zero-length barrier to every active device. When that completes - and if the original request was not empty - we submit the barrier request itself (with the barrier flag cleared) and then submit a fresh load of zero length barriers. The barrier request itself is asynchronous, but any subsequent request will block until the barrier completes. The reason for clearing the barrier flag is that a barrier request is allowed to fail. If we pass a non-empty barrier through a striping raid level it is conceivable that part of it could succeed and part could fail. That would be way too hard to deal with. So if the first run of zero length barriers succeed, we assume all is sufficiently well that we send the request and ignore errors in the second run of barriers. RAID5 needs extra care as write requests may not have been submitted to the underlying devices yet. So we flush the stripe cache before proceeding with the barrier. Note that the second set of zero-length barriers are submitted immediately after the original request is submitted. Thus when a personality finds mddev->barrier to be set during make_request, it should not return from make_request until the corresponding per-device request(s) have been queued. That will be done in later patches. Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Andre Noll <maan@systemlinux.org>
* md/bitmap: protect against bitmap removal while being updated.NeilBrown2009-12-141-0/+1
| | | | | | | | | | | | | | | | | | A write intent bitmap can be removed from an array while the array is active. When this happens, all IO is suspended and flushed before the bitmap is removed. However it is possible that bitmap_daemon_work is still running to clear old bits from the bitmap. If it is, it can dereference the bitmap after it has been freed. So introduce a new mutex to protect bitmap_daemon_work and get it before destroying a bitmap. This is suitable for any current -stable kernel. Signed-off-by: NeilBrown <neilb@suse.de> Cc: stable@kernel.org
* md: report device as congested when suspendedNeilBrown2009-09-231-0/+1
| | | | | | | This should writeback from coming when the device is temporarily suspended. Signed-off-by: NeilBrown <neilb@suse.de>
* trivial: fix typo "for for" in multiple filesAnand Gadiyar2009-09-211-1/+1
| | | | | | | trivial: fix typo "for for" in multiple files Signed-off-by: Anand Gadiyar <gadiyar@ti.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* Remove deadlock potential in md_openNeilBrown2009-08-101-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A recent commit: commit 449aad3e25358812c43afc60918c5ad3819488e7 introduced the possibility of an A-B/B-A deadlock between bd_mutex and reconfig_mutex. __blkdev_get holds bd_mutex while calling md_open which takes reconfig_mutex, do_md_run is always called with reconfig_mutex held, and it now takes bd_mutex in the call the revalidate_disk. This potential deadlock was not caught by lockdep due to the use of mutex_lock_interruptible_nexted which was introduced by commit d63a5a74dee87883fda6b7d170244acaac5b05e8 do avoid a warning of an impossible deadlock. It is quite possible to split reconfig_mutex in to two locks. One protects the array data structures while it is being reconfigured, the other ensures that an array is never even partially open while it is being deactivated. In particular, the second lock prevents an open from completing between the time when do_md_stop checks if there are any active opens, and the time when the array is either set read-only, or when ->pers is set to NULL. So we can be certain that no IO is in flight as the array is being destroyed. So create a new lock, open_mutex, just to ensure exclusion between 'open' and 'stop'. This avoids the deadlock and also avoids the lockdep warning mentioned in commit d63a5a74d Reported-by: "Mike Snitzer" <snitzer@gmail.com> Reported-by: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: NeilBrown <neilb@suse.de>
* md: Push down data integrity code to personalities.Andre Noll2009-08-031-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | This patch replaces md_integrity_check() by two new public functions: md_integrity_register() and md_integrity_add_rdev() which are both personality-independent. md_integrity_register() is called from the ->run and ->hot_remove methods of all personalities that support data integrity. The function iterates over the component devices of the array and determines if all active devices are integrity capable and if their profiles match. If this is the case, the common profile is registered for the mddev via blk_integrity_register(). The second new function, md_integrity_add_rdev() is called from the ->hot_add_disk methods, i.e. whenever a new device is being added to a raid array. If the new device does not support data integrity, or has a profile different from the one already registered, data integrity for the mddev is disabled. For raid0 and linear, only the call to md_integrity_register() from the ->run method is necessary. Signed-off-by: Andre Noll <maan@systemlinux.org> Signed-off-by: NeilBrown <neilb@suse.de>
* md: Move check for bitmap presence to personality code.Andre Noll2009-06-181-0/+1
| | | | | | | | | | | | | | | | | | | | | | | If the superblock of a component device indicates the presence of a bitmap but the corresponding raid personality does not support bitmaps (raid0, linear, multipath, faulty), then something is seriously wrong and we'd better refuse to run such an array. Currently, this check is performed while the superblocks are examined, i.e. before entering personality code. Therefore the generic md layer must know which raid levels support bitmaps and which do not. This patch avoids this layer violation without adding identical code to various personalities. This is accomplished by introducing a new public function to md.c, md_check_no_bitmap(), which replaces the hard-coded checks in the superblock loading functions. A call to md_check_no_bitmap() is added to the ->run method of each personality which does not support bitmaps and assembly is aborted if at least one component device contains a bitmap. Signed-off-by: Andre Noll <maan@systemlinux.org> Signed-off-by: NeilBrown <neilb@suse.de>
* md: remove chunksize rounding from common code.NeilBrown2009-06-181-7/+0
| | | | | | | | | | | | | It is easiest to round sizes to multiples of chunk size in the personality code for those personalities which care. Those personalities now do the rounding, so we can remove that function from common code. Also remove the upper bound on the size of a chunk, and the lower bound on the size of a device (1 chunk), neither of which really buy us anything. Signed-off-by: NeilBrown <neilb@suse.de>
* md: merge reconfig and check_reshape methods.NeilBrown2009-06-181-1/+0
| | | | | | | | | | | | The difference between these two methods is artificial. Both check that a pending reshape is valid, and perform any aspect of it that can be done immediately. 'reconfig' handles chunk size and layout. 'check_reshape' handles raid_disks. So make them just one method. Signed-off-by: NeilBrown <neilb@suse.de>
* md: remove unnecessary arguments from ->reconfig method.NeilBrown2009-06-181-1/+1
| | | | | | | | | | Passing the new layout and chunksize as args is not necessary as the mddev has fields for new_check and new_layout. This is preparation for combining the check_reshape and reconfig methods Signed-off-by: NeilBrown <neilb@suse.de>
* md: Convert mddev->new_chunk to sectors.Andre Noll2009-06-181-1/+2
| | | | | | | | | | A straight-forward conversion which gets rid of some multiplications/divisions/shifts. The patch also introduces a couple of new ones, most of which are due to conf->chunk_size still being represented in bytes. This will be cleaned up in subsequent patches. Signed-off-by: Andre Noll <maan@systemlinux.org> Signed-off-by: NeilBrown <neilb@suse.de>
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