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path: root/drivers/md
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2010-08-13md/raid10: fix deadlock with unaligned read during resyncNeilBrown
commit 51e9ac77035a3dfcb6fc0a88a0d80b6f99b5edb1 upstream. If the 'bio_split' path in raid10-read is used while resync/recovery is happening it is possible to deadlock. Fix this be elevating ->nr_waiting for the duration of both parts of the split request. This fixes a bug that has been present since 2.6.22 but has only started manifesting recently for unknown reasons. It is suitable for and -stable since then. Reported-by: Justin Bronder <jsbronder@gentoo.org> Tested-by: Justin Bronder <jsbronder@gentoo.org> Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-08-13md: fix another deadlock with removing sysfs attributes.NeilBrown
commit bb4f1e9d0e2ef93de8e36ca0f5f26625fcd70b7d upstream. 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 Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-08-13md: move revalidate_disk() back outside open_mutexDan Williams
commit 147e0b6a639ac581ca3bf627bedc3f4a6d3eca66 upstream. Commit b821eaa5 "md: remove ->changed and related code" moved revalidate_disk() under open_mutex, and lockdep noticed. [ INFO: possible circular locking dependency detected ] 2.6.32-mdadm-locking #1 ------------------------------------------------------- mdadm/3640 is trying to acquire lock: (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff811acecb>] revalidate_disk+0x5b/0x90 but task is already holding lock: (&mddev->open_mutex){+.+...}, at: [<ffffffffa055e07a>] do_md_stop+0x4a/0x4d0 [md_mod] which lock already depends on the new lock. It is suitable for 2.6.35.x Reported-by: Przemyslaw Czarnowski <przemyslaw.hawrylewicz.czarnowski@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-06-24md/raid5: don't include 'spare' drives when reshaping to fewer devices.NeilBrown
There are few situations where it would make any sense to add a spare when reducing the number of devices in an array, but it is conceivable: A 6 drive RAID6 with two missing devices could be reshaped to a 5 drive RAID6, and a spare could become available just in time for the reshape, but not early enough to have been recovered first. 'freezing' recovery can make this easy to do without any races. However doing such a thing is a bad idea. md will not record the partially-recovered state of the 'spare' and when the reshape finished it will think that the spare is still spare. Easiest way to avoid this confusion is to simply disallow it. Signed-off-by: NeilBrown <neilb@suse.de>
2010-06-24md/raid5: add a missing 'continue' in a loop.NeilBrown
As the comment says, the tail of this loop only applies to devices that are not fully in sync, so if In_sync was set, we should avoid the rest of the loop. This bug will hardly ever cause an actual problem. The worst it can do is allow an array to be assembled that is dirty and degraded, which is not generally a good idea (without warning the sysadmin first). This will only happen if the array is RAID4 or a RAID5/6 in an intermediate state during a reshape and so has one drive that is all 'parity' - no data - while some other device has failed. This is certainly possible, but not at all common. Signed-off-by: NeilBrown <neilb@suse.de>
2010-06-24md/raid5: Allow recovered part of partially recovered devices to be in-syncNeilBrown
During a recovery of reshape the early part of some devices might be in-sync while the later parts are not. We we know we are looking at an early part it is good to treat that part as in-sync for stripe calculations. This is particularly important for a reshape which suffers device failure. Treating the data as in-sync can mean the difference between data-safety and data-loss. Signed-off-by: NeilBrown <neilb@suse.de>
2010-06-24md/raid5: More careful check for "has array failed".NeilBrown
When we are reshaping an array, the device failure combinations that cause us to decide that the array as failed are more subtle. In particular, any 'spare' will be fully in-sync in the section of the array that has already been reshaped, thus failures that affect only that section are less critical. So encode this subtlety in a new function and call it as appropriate. The case that showed this problem was a 4 drive RAID5 to 8 drive RAID6 conversion where the last two devices failed. This resulted in: good good good good incomplete good good failed failed while converting a 5-drive RAID6 to 8 drive RAID5 The incomplete device causes the whole array to look bad, bad as it was actually good for the section that had been converted to 8-drives, all the data was actually safe. Reported-by: Terry Morris <tbmorris@tbmorris.com> Signed-off-by: NeilBrown <neilb@suse.de>
2010-06-24md: Don't update ->recovery_offset when reshaping an array to fewer devices.NeilBrown
When an array is reshaped to have fewer devices, the reshape proceeds from the end of the devices to the beginning. If a device happens to be non-In_sync (which is possible but rare) we would normally update the ->recovery_offset as the reshape progresses. However that would be wrong as the recover_offset records that the early part of the device is in_sync, while in fact it would only be the later part that is in_sync, and in any case the offset number would be measured from the wrong end of the device. Relatedly, if after a reshape a spare is discovered to not be recoverred all the way to the end, not allow spare_active to incorporate it in the array. This becomes relevant in the following sample scenario: A 4 drive RAID5 is converted to a 6 drive RAID6 in a combined operation. The RAID5->RAID6 conversion will cause a 5 drive to be included as a spare, then the 5drive -> 6drive reshape will effectively rebuild that spare as it progresses. The 6th drive is treated as in_sync the whole time as there is never any case that we might consider reading from it, but must not because there is no valid data. If we interrupt this reshape part-way through and reverse it to return to a 5-drive RAID6 (or event a 4-drive RAID5), we don't want to update the recovery_offset - as that would be wrong - and we don't want to include that spare as active in the 5-drive RAID6 when the reversed reshape completed and it will be mostly out-of-sync still. Signed-off-by: NeilBrown <neilb@suse.de>
2010-06-24md/raid5: avoid oops when number of devices is reduced then increased.NeilBrown
The entries in the stripe_cache maintained by raid5 are enlarged when we increased the number of devices in the array, but not shrunk when we reduce the number of devices. So if entries are added after reducing the number of devices, we much ensure to initialise the whole entry, not just the part that is currently relevant. Otherwise if we enlarge the array again, we will reference uninitialised values. As grow_buffers/shrink_buffer now want to use a count that is stored explicity in the raid_conf, they should get it from there rather than being passed it as a parameter. Signed-off-by: NeilBrown <neilb@suse.de>
2010-06-24md: enable raid4->raid0 takeoverMaciej Trela
Only level 5 with layout=PARITY_N can be taken over to raid0 now. Lets allow level 4 either. Signed-off-by: Maciej Trela <maciej.trela@intel.com> Signed-off-by: NeilBrown <neilb@suse.de>
2010-06-24md: clear layout after ->raid0 takeoverMaciej Trela
After takeover from raid5/10 -> raid0 mddev->layout is not cleared. Signed-off-by: Maciej Trela <maciej.trela@intel.com> Signed-off-by: NeilBrown <neilb@suse.de>
2010-06-24md: fix raid10 takeover: use new_layout for setup_confMaciej Trela
Use mddev->new_layout in setup_conf. Also use new_chunk, and don't set ->degraded in takeover(). That gets set in run() Signed-off-by: Maciej Trela <maciej.trela@intel.com> Signed-off-by: NeilBrown <neilb@suse.de>
2010-06-24md: fix handling of array level takeover that re-arranges devices.NeilBrown
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>
2010-06-24md: raid10: Fix null pointer dereference in fix_read_error()Prasanna S. Panchamukhi
Such NULL pointer dereference can occur when the driver was fixing the read errors/bad blocks and the disk was physically removed causing a system crash. This patch check if the rcu_dereference() returns valid rdev before accessing it in fix_read_error(). Cc: stable@kernel.org Signed-off-by: Prasanna S. Panchamukhi <prasanna.panchamukhi@riverbed.com> Signed-off-by: Rob Becker <rbecker@riverbed.com> Signed-off-by: NeilBrown <neilb@suse.de>
2010-06-24Restore partition detection of newly created md arrays.NeilBrown
Commit b821eaa572fd737faaf6928ba046e571526c36c6 broke partition detection for md arrays. The logic was almost right. However if revalidate_disk is called when the device is not yet open, bdev->bd_disk won't be set, so the flush_disk() Call will not set bd_invalidated. So when md_open is called we still need to ensure that ->bd_invalidated gets set. This is easily done with a call to check_disk_size_change in the place where the offending commit removed check_disk_change. At the important times, the size will have changed from 0 to non-zero, so check_disk_size_change will set bd_invalidated. Tested-by: Duncan <1i5t5.duncan@cox.net> Reported-by: Duncan <1i5t5.duncan@cox.net> Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-27md: convert cpu notifier to return encapsulate errno valueAkinobu Mita
By the previous modification, the cpu notifier can return encapsulate errno value. This converts the cpu notifiers for raid5. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-21Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (69 commits) fix handling of offsets in cris eeprom.c, get rid of fake on-stack files get rid of home-grown mutex in cris eeprom.c switch ecryptfs_write() to struct inode *, kill on-stack fake files switch ecryptfs_get_locked_page() to struct inode * simplify access to ecryptfs inodes in ->readpage() and friends AFS: Don't put struct file on the stack Ban ecryptfs over ecryptfs logfs: replace inode uid,gid,mode initialization with helper function ufs: replace inode uid,gid,mode initialization with helper function udf: replace inode uid,gid,mode init with helper ubifs: replace inode uid,gid,mode initialization with helper function sysv: replace inode uid,gid,mode initialization with helper function reiserfs: replace inode uid,gid,mode initialization with helper function ramfs: replace inode uid,gid,mode initialization with helper function omfs: replace inode uid,gid,mode initialization with helper function bfs: replace inode uid,gid,mode initialization with helper function ocfs2: replace inode uid,gid,mode initialization with helper function nilfs2: replace inode uid,gid,mode initialization with helper function minix: replace inode uid,gid,mode init with helper ext4: replace inode uid,gid,mode init with helper ... Trivial conflict in fs/fs-writeback.c (mark bitfields unsigned)
2010-05-22Merge commit '3ff195b011d7decf501a4d55aeed312731094796' into for-linusNeilBrown
Conflicts: drivers/md/md.c - Resolved conflict in md_update_sb - Added extra 'NULL' arg to new instance of sysfs_get_dirent. Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-21sanitize vfs_fsync calling conventionsChristoph Hellwig
Now that the last user passing a NULL file pointer is gone we can remove the redundant dentry argument and associated hacks inside vfs_fsynmc_range. The next step will be removig the dentry argument from ->fsync, but given the luck with the last round of method prototype changes I'd rather defer this until after the main merge window. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-21sysfs: Implement sysfs tagged directory support.Eric W. Biederman
The problem. When implementing a network namespace I need to be able to have multiple network devices with the same name. Currently this is a problem for /sys/class/net/*, /sys/devices/virtual/net/*, and potentially a few other directories of the form /sys/ ... /net/*. What this patch does is to add an additional tag field to the sysfs dirent structure. For directories that should show different contents depending on the context such as /sys/class/net/, and /sys/devices/virtual/net/ this tag field is used to specify the context in which those directories should be visible. Effectively this is the same as creating multiple distinct directories with the same name but internally to sysfs the result is nicer. I am calling the concept of a single directory that looks like multiple directories all at the same path in the filesystem tagged directories. For the networking namespace the set of directories whose contents I need to filter with tags can depend on the presence or absence of hotplug hardware or which modules are currently loaded. Which means I need a simple race free way to setup those directories as tagged. To achieve a reace free design all tagged directories are created and managed by sysfs itself. Users of this interface: - define a type in the sysfs_tag_type enumeration. - call sysfs_register_ns_types with the type and it's operations - sysfs_exit_ns when an individual tag is no longer valid - Implement mount_ns() which returns the ns of the calling process so we can attach it to a sysfs superblock. - Implement ktype.namespace() which returns the ns of a syfs kobject. Everything else is left up to sysfs and the driver layer. For the network namespace mount_ns and namespace() are essentially one line functions, and look to remain that. Tags are currently represented a const void * pointers as that is both generic, prevides enough information for equality comparisons, and is trivial to create for current users, as it is just the existing namespace pointer. The work needed in sysfs is more extensive. At each directory or symlink creating I need to check if the directory it is being created in is a tagged directory and if so generate the appropriate tag to place on the sysfs_dirent. Likewise at each symlink or directory removal I need to check if the sysfs directory it is being removed from is a tagged directory and if so figure out which tag goes along with the name I am deleting. Currently only directories which hold kobjects, and symlinks are supported. There is not enough information in the current file attribute interfaces to give us anything to discriminate on which makes it useless, and there are no potential users which makes it an uninteresting problem to solve. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Benjamin Thery <benjamin.thery@bull.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-05-18md: don't insist on valid event count for spare devices.NeilBrown
Devices which know that they are spares do not really need to have an event count that matches the rest of the array, so there are no data-in-sync issues. It is enough that the uuid matches. So remove the requirement that the event count is up-to-date. We currently still write out and event count on spares, but this allows us in a year or 3 to stop doing that completely. Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md: simplify updating of event count to sometimes avoid updating spares.NeilBrown
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>
2010-05-18md/raid6: Fix raid-6 read-error correction in degraded stateGabriele A. Trombetti
Fix: Raid-6 was not trying to correct a read-error when in singly-degraded state and was instead dropping one more device, going to doubly-degraded state. This patch fixes this behaviour. Tested-by: Janos Haar <janos.haar@netcenter.hu> Signed-off-by: Gabriele A. Trombetti <g.trombetti.lkrnl1213@logicschema.com> Reported-by: Janos Haar <janos.haar@netcenter.hu> Signed-off-by: NeilBrown <neilb@suse.de> Cc: stable@kernel.org
2010-05-18md: restore ability of spare drives to spin down.NeilBrown
Some time ago we stopped the clean/active metadata updates from being written to a 'spare' device in most cases so that it could spin down and say spun down. Device failure/removal etc are still recorded on spares. However commit 51d5668cb2e3fd1827a55 broke this 50% of the time, depending on whether the event count is even or odd. The change log entry said: This means that the alignment between 'odd/even' and 'clean/dirty' might take a little longer to attain, how ever the code makes no attempt to create that alignment, so it could take arbitrarily long. So when we find that clean/dirty is not aligned with odd/even, force a second metadata-update immediately. There are already cases where a second metadata-update is needed immediately (e.g. when a device fails during the metadata update). We just piggy-back on that. Reported-by: Joe Bryant <tenminjoe@yahoo.com> Signed-off-by: NeilBrown <neilb@suse.de> Cc: stable@kernel.org
2010-05-18md: Fix read balancing in RAID1 and RAID10 on drives > 2TBNeilBrown
read_balance uses a "unsigned long" for a sector number which will get truncated beyond 2TB. This will cause read-balancing to be non-optimal, and can cause data to be read from the 'wrong' branch during a resync. This has a very small chance of returning wrong data. Reported-by: Jordan Russell <jr-list-2010@quo.to> Cc: stable@kernel.org Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md/linear: standardise all printk messagesNeilBrown
md/linear:mdname: Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md/raid0: tidy up printk messages.NeilBrown
All messages now start md/raid0:md-device-name: Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md/raid10: tidy up printk messages.NeilBrown
All raid10 printk messages now start md/raid10:md-device-name: Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md/raid1: improve printk messagesNeilBrown
Make sure the array name is included in a uniform way in all printk messages. Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md/raid5: improve consistency of error messages.NeilBrown
Many 'printk' messages from the raid456 module mention 'raid5' even though it may be a 'raid6' or even 'raid4' array. This can cause confusion. Also the actual array name is not always reported and when it is it is not reported consistently. So change all the messages to start: md/raid:%s: where '%s' becomes e.g. md3 to identify the particular array. Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md: remove EXPERIMENTAL designation from RAID10NeilBrown
RAID10 has been available for quite a while now and is quite well tested, so we can remove the EXPERIMENTAL designation. Reported-by: Eric MSP Veith <eveith@wwweb-library.net> Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md: allow integers to be passed to md/levelDan Williams
e.g. allow md to interpret 'echo 4 > md/level' as a request for raid4. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2010-05-18md: notify mdstat waiters of level changeDan Williams
Level modifications change the output of mdstat. The mdmon manager thread is interested in these events for external metadata management. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2010-05-18md/raid4: permit raid0 takeoverDan Williams
For consistency allow raid4 to takeover raid0 in addition to raid5 (with a raid4 layout). Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2010-05-18md/raid1: delay reads that could overtake behind-writes.NeilBrown
When a raid1 array is configured to support write-behind on some devices, it normally only reads from other devices. If all devices are write-behind (because the rest have failed) it is possible for a read request to be serviced before a behind-write request, which would appear as data corruption. So when forced to read from a WriteMostly device, wait for any write-behind to complete, and don't start any more behind-writes. Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md/raid1: fix confusing 'redirect sector' message.NeilBrown
This message seems to suggest the named device is the one on which a read failed, however it is actually the device that the read will be redirected to. So make the message a little clearer. Reported-by: Tim Burgess <ozburgess@gmail.com> Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md: don't unregister the thread in mddev_suspendNeilBrown
This is - unnecessary because mddev_suspend is always followed by a call to ->stop, and each ->stop unregisters the thread, and - a problem as it makes it awkwards to suspend and then resume a device as we will want later. Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md: factor out init code for an mddevNeilBrown
This is a simple factorisation that makes mddev_find easier to read. Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md: pass mddev to make_request functions rather than request_queueNeilBrown
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>
2010-05-18md: call md_stop_writes from md_stopNeilBrown
This moves the call to the other side of set_readonly, but that should not be an issue. This encapsulates in 'md_stop' all of the functionality for internally stopping the array, leaving all the interactions with externalities (sysfs, request_queue, gendisk) in do_md_stop. Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md: split md_set_readonly out of do_md_stopNeilBrown
Using do_md_stop to set an array to read-only is a little confusing. Now most of the common code has been factored out, split md_set_readonly off in to a separate function. Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md: factor md_stop_writes out of do_md_stop.NeilBrown
Further refactoring of do_md_stop. This one requires some explanation as it takes code from different places in do_md_stop, so some re-ordering happens. We only get into this part of do_md_stop if there are no active opens of the device, so no writes can be happening and the device must have been flushed. In md_stop_writes we want to stop any internal sources of writes - i.e. resync - and flush out the metadata. The only code that was previously before some of this code is code to clean up the queue, the mddev, the gendisk, or sysfs, all of which is probably better after code that makes active changes (i.e. triggers writes). Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md: start to refactor do_md_stopNeilBrown
do_md_stop is large and clunky, so hard to understand. This is a first step of refactoring, pulling two simple sub-functions out. Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md: factor do_md_run to separate accesses to ->gendiskNeilBrown
As part of relaxing the binding between an mddev and gendisk, we separate do_md_run into two functions. md_run does all the work internal to md do_md_run calls md_run and makes and changes to gendisk that are required. Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md: remove ->changed and related code.NeilBrown
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>
2010-05-18md: don't reference gendisk in getgeoNeilBrown
Using ->array_sectors rather than get_capacity() is more direct and is a step towards relaxing the tight connection between mddev and gendisk. Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md: move io accounting out of personalities into md_make_requestNeilBrown
While I generally prefer letting personalities do as much as possible, given that we have a central md_make_request anyway we may as well use it to simplify code. Also this centralises knowledge of ->gendisk which will help later. Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md/raid5: small tidyup in raid5_align_endioNeilBrown
Diving through ->queue to find mddev is unnecessarily complex - there is an easier path to finding mddev, so use that. Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md: add support for raid5 to raid4 conversionNeilBrown
This is unlikely to be wanted, but we may as well provide it for completeness. Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18md: notify level changes through sysfs.Maciej Trela
Level changes can be very significant, so make sure to notify them via sysfs. Signed-off-by: Maciej Trela <maciej.trela@intel.com> Signed-off-by: NeilBrown <neilb@suse.de>