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path: root/drivers/md/raid10.c
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* md: the md RAID10 resync thread could cause a md RAID10 array deadlockK.Tanaka2008-03-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This message describes another issue about md RAID10 found by testing the 2.6.24 md RAID10 using new scsi fault injection framework. Abstract: When a scsi error results in disabling a disk during RAID10 recovery, the resync threads of md RAID10 could stall. This case, the raid array has already been broken and it may not matter. But I think stall is not preferable. If it occurs, even shutdown or reboot will fail because of resource busy. The deadlock mechanism: The r10bio_s structure has a "remaining" member to keep track of BIOs yet to be handled when recovering. The "remaining" counter is incremented when building a BIO in sync_request() and is decremented when finish a BIO in end_sync_write(). If building a BIO fails for some reasons in sync_request(), the "remaining" should be decremented if it has already been incremented. I found a case where this decrement is forgotten. This causes a md_do_sync() deadlock because md_do_sync() waits for md_done_sync() called by end_sync_write(), but end_sync_write() never calls md_done_sync() because of the "remaining" counter mismatch. For example, this problem would be reproduced in the following case: Personalities : [raid10] md0 : active raid10 sdf1[4] sde1[5](F) sdd1[2] sdc1[1] sdb1[6](F) 3919616 blocks 64K chunks 2 near-copies [4/2] [_UU_] [>....................] recovery = 2.2% (45376/1959808) finish=0.7min speed=45376K/sec This case, sdf1 is recovering, sdb1 and sde1 are disabled. An additional error with detaching sdd will cause a deadlock. md0 : active raid10 sdf1[4] sde1[5](F) sdd1[6](F) sdc1[1] sdb1[7](F) 3919616 blocks 64K chunks 2 near-copies [4/1] [_U__] [=>...................] recovery = 5.0% (99520/1959808) finish=5.9min speed=5237K/sec 2739 ? S< 0:17 [md0_raid10] 28608 ? D< 0:00 [md0_resync] 28629 pts/1 Ss 0:00 bash 28830 pts/1 R+ 0:00 ps ax 31819 ? D< 0:00 [kjournald] The resync thread keeps working, but actually it is deadlocked. Patch: By this patch, the remaining counter will be decremented if needed. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* md: fix possible raid1/raid10 deadlock on read error during resyncNeilBrown2008-03-04
| | | | | | | | | | | | | | | | | Thanks to K.Tanaka and the scsi fault injection framework, here is a fix for another possible deadlock in raid1/raid10 error handing. If a read request returns an error while a resync is happening and a resync request is pending, the attempt to fix the error will block until the resync progresses, and the resync will block until the read request completes. Thus a deadlock. This patch fixes the problem. Cc: "K.Tanaka" <k-tanaka@ce.jp.nec.com> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* md: don't attempt read-balancing for raid10 'far' layoutsKeld Simonsen2008-03-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch changes the disk to be read for layout "far > 1" to always be the disk with the lowest block address. Thus the chunks to be read will always be (for a fully functioning array) from the first band of stripes, and the raid will then work as a raid0 consisting of the first band of stripes. Some advantages: The fastest part which is the outer sectors of the disks involved will be used. The outer blocks of a disk may be as much as 100 % faster than the inner blocks. Average seek time will be smaller, as seeks will always be confined to the first part of the disks. Mixed disks with different performance characteristics will work better, as they will work as raid0, the sequential read rate will be number of disks involved times the IO rate of the slowest disk. If a disk is malfunctioning, the first disk which is working, and has the lowest block address for the logical block will be used. Signed-off-by: Keld Simonsen <keld@dkuug.dk> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* md: fix deadlock in md/raid1 and md/raid10 when handling a read errorNeilBrown2008-03-04
| | | | | | | | | | | | | | | | | | | | | | | | When handling a read error, we freeze the array to stop any other IO while attempting to over-write with correct data. This is done in the raid1d(raid10d) thread and must wait for all submitted IO to complete (except for requests that failed and are sitting in the retry queue - these are counted in ->nr_queue and will stay there during a freeze). However write requests need attention from raid1d as bitmap updates might be required. This can cause a deadlock as raid1 is waiting for requests to finish that themselves need attention from raid1d. So we create a new function 'flush_pending_writes' to give that attention, and call it in freeze_array to be sure that we aren't waiting on raid1d. Thanks to "K.Tanaka" <k-tanaka@ce.jp.nec.com> for finding and reporting this problem. Cc: "K.Tanaka" <k-tanaka@ce.jp.nec.com> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* md: change ITERATE_RDEV to rdev_for_eachNeilBrown2008-02-06
| | | | | | | | | As this is more in line with common practice in the kernel. Also swap the args around to be more like list_for_each. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* md: allow a maximum extent to be set for resyncingNeilBrown2008-02-06
| | | | | | | | | | | | | This allows userspace to control resync/reshape progress and synchronise it with other activities, such as shared access in a SAN, or backing up critical sections during a tricky reshape. Writing a number of sectors (which must be a multiple of the chunk size if such is meaningful) causes a resync to pause when it gets to that point. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* md: Update md bitmap during resync.NeilBrown2008-02-06
| | | | | | | | | | | | | | | | | | | | Currently an md array with a write-intent bitmap does not updated that bitmap to reflect successful partial resync. Rather the entire bitmap is updated when the resync completes. This is because there is no guarentee that resync requests will complete in order, and tracking each request individually is unnecessarily burdensome. However there is value in regularly updating the bitmap, so add code to periodically pause while all pending sync requests complete, then update the bitmap. Doing this only every few seconds (the same as the bitmap update time) does not notciably affect resync performance. [snitzer@gmail.com: export bitmap_cond_end_sync] Signed-off-by: Neil Brown <neilb@suse.de> Cc: "Mike Snitzer" <snitzer@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Add UNPLUG traces to all appropriate placesAlan D. Brunelle2007-11-09
| | | | | | | | Added blk_unplug interface, allowing all invocations of unplugs to result in a generated blktrace UNPLUG. Signed-off-by: Alan D. Brunelle <Alan.Brunelle@hp.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: convert blkdev_issue_flush() to use empty barriersJens Axboe2007-10-16
| | | | | | | Then we can get rid of ->issue_flush_fn() and all the driver private implementations of that. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* Drop 'size' argument from bio_endio and bi_end_ioNeilBrown2007-10-10
| | | | | | | | | | | | | As bi_end_io is only called once when the reqeust is complete, the 'size' argument is now redundant. Remove it. Now there is no need for bio_endio to subtract the size completed from bi_size. So don't do that either. While we are at it, change bi_end_io to return void. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* md: handle writes to broken raid10 arrays gracefullyArne Redlich2007-07-31
| | | | | | | | | | | | When writing to a broken array, raid10 currently happily emits empty bio lists. IOW, the master bio will never be completed, sending writers to UNINTERRUPTIBLE_SLEEP forever. Signed-off-by: Arne Redlich <agr@powerkom-dd.de> Acked-by: Neil Brown <neilb@suse.de> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* md: raid10: fix use-after-free of bioMaik Hampel2007-07-31
| | | | | | | | | | | In case of read errors raid10d tries to print a nice error message, unfortunately using data from an already put bio. Signed-off-by: Maik Hampel <m.hampel@gmx.de> Acked-By: NeilBrown <neilb@suse.de> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [BLOCK] Get rid of request_queue_t typedefJens Axboe2007-07-24
| | | | | | | | | Some of the code has been gradually transitioned to using the proper struct request_queue, but there's lots left. So do a full sweet of the kernel and get rid of this typedef and replace its uses with the proper type. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* md: change bitmap_unplug and others to void functionsNeilBrown2007-07-17
| | | | | | | | | | | | | | | | | | | | | | bitmap_unplug only ever returns 0, so it may as well be void. Two callers try to print a message if it returns non-zero, but that message is already printed by bitmap_file_kick. write_page returns an error which is not consistently checked. It always causes BITMAP_WRITE_ERROR to be set on an error, and that can more conveniently be checked. When the return of write_page is checked, an error causes bitmap_file_kick to be called - so move that call into write_page - and protect against recursive calls into bitmap_file_kick. bitmap_update_sb returns an error that is never checked. So make these 'void' and be consistent about checking the bit. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* md: fix two raid10 bugsNeilBrown2007-06-16
| | | | | | | | | | | | | 1/ When resyncing a degraded raid10 which has more than 2 copies of each block, garbage can get synced on top of good data. 2/ We round the wrong way in part of the device size calculation, which can cause confusion. Signed-off-by: Neil Brown <neilb@suse.de> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] md: fix raid10 recovery problem.NeilBrown2007-03-01
| | | | | | | | | | | | | | | | | | | | There are two errors that can lead to recovery problems with raid10 when used in 'far' more (not the default). Due to a '>' instead of '>=' the wrong block is located which would result in garbage being written to some random location, quite possible outside the range of the device, causing the newly reconstructed device to fail. The device size calculation had some rounding errors (it didn't round when it should) and so recovery would go a few blocks too far which would again cause a write to a random block address and probably a device error. The code for working with device sizes was fairly confused and spread out, so this has been tided up a bit. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] md: pass down BIO_RW_SYNC in raid{1,10}Lars Ellenberg2007-01-11
| | | | | | | | | | | | | | | | | md raidX make_request functions strip off the BIO_RW_SYNC flag, thus introducing additional latency. Fixing this in raid1 and raid10 seems to be straightforward enough. For our particular usage case in DRBD, passing this flag improved some initialization time from ~5 minutes to ~5 seconds. Acked-by: NeilBrown <neilb@suse.de> Signed-off-by: Lars Ellenberg <lars@linbit.com> Acked-by: Jens Axboe <jens.axboe@oracle.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: Don't assume that READ==0 and WRITE==1 - use the names explicitlyNeilBrown2006-12-13
| | | | | | | | | | Thanks Jens for alerting me to this. Cc: Jens Axboe <jens.axboe@oracle.com> Cc: <raziebe@gmail.com> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: fix printk format warnings, seen on powerpc64:Randy Dunlap2006-10-28
| | | | | | | | | | drivers/md/raid1.c:1479: warning: long long unsigned int format, long unsigned int arg (arg 4) drivers/md/raid10.c:1475: warning: long long unsigned int format, long unsigned int arg (arg 4) Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: fix calculation of ->degraded for multipath and raid10NeilBrown2006-10-21
| | | | | | | | | | Two less-used md personalities have bugs in the calculation of ->degraded (the extent to which the array is degraded). Signed-off-by: Neil Brown <neilb@suse.de> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: define ->congested_fn for raid1, raid10, and multipathNeilBrown2006-10-03
| | | | | | | | | | | | | | | | | raid1, raid10 and multipath don't report their 'congested' status through bdi_*_congested, but should. This patch adds the appropriate functions which just check the 'congested' status of all active members (with appropriate locking). raid1 read_balance should be modified to prefer devices where bdi_read_congested returns false. Then we could use the '&' branch rather than the '|' branch. However that should would need some benchmarking first to make sure it is actually a good idea. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: Improve locking around error handlingNeilBrown2006-10-03
| | | | | | | | | | | | | | | | | | The error handling routines don't use proper locking, and so two concurrent errors could trigger a problem. So: - use test-and-set and test-and-clear to synchonise the In_sync bits with the ->degraded count - use the spinlock to protect updates to the degraded count (could use an atomic_t but that would be a bigger change in code, and isn't really justified) - remove un-necessary locking in raid5 Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: remove 'working_disks' from raid10 stateNeilBrown2006-10-03
| | | | | | | | It isn't needed as mddev->degraded contains equivalent info. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: replace magic numbers in sb_dirty with well defined bit flagsNeilBrown2006-10-03
| | | | | | | | | | | | | | | | | | | | | | | | Instead of magic numbers (0,1,2,3) in sb_dirty, we have some flags instead: MD_CHANGE_DEVS Some device state has changed requiring superblock update on all devices. MD_CHANGE_CLEAN The array has transitions from 'clean' to 'dirty' or back, requiring a superblock update on active devices, but possibly not on spares MD_CHANGE_PENDING A superblock update is underway. We wait for an update to complete by waiting for all flags to be clear. A flag can be set at any time, even during an update, without risk that the change will be lost. Stop exporting md_update_sb - isn't needed. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: factor out part of raid10d into a separate function.NeilBrown2006-10-03
| | | | | | | | | raid10d has toooo many nested block, so take the fix_read_error functionality out into a separate function. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: include sector number in messages about corrected read errorsNeilBrown2006-07-10
| | | | | | | | | | This is generally useful, but particularly helps see if it is the same sector that always needs correcting, or different ones. [akpm@osdl.org: fix printk warnings] Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: Calculate correct array size for raid10 in new offset modeNeilBrown2006-06-26
| | | | | | | | | The size calculation made assumtion which the new offset mode didn't follow. This gets the size right in all cases. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: support stripe/offset mode in raid10NeilBrown2006-06-26
| | | | | | | | | | | | | | | | | | | | The "industry standard" DDF format allows for a stripe/offset layout where data is duplicated on different stripes. e.g. A B C D D A B C E F G H H E F G (columns are drives, rows are stripes, LETTERS are chunks of data). This is similar to raid10's 'far' mode, but not quite the same. So enhance 'far' mode with a 'far/offset' option which follows the layout of DDFs stripe/offset. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: allow checkpoint of recovery with version-1 superblockNeilBrown2006-06-26
| | | | | | | | | | | | | For a while we have had checkpointing of resync. The version-1 superblock allows recovery to be checkpointed as well, and this patch implements that. Due to early carelessness we need to add a feature flag to signal that the recovery_offset field is in use, otherwise older kernels would assume that a partially recovered array is in fact fully recovered. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: remove arbitrary limit on chunk sizeNeilBrown2006-06-26
| | | | | | | | | | | The largest chunk size the code can support without substantial surgery is 2^30 bytes, so make that the limit instead of an arbitrary 4Meg. Some day, the 'chunksize' should change to a sector-shift instead of a byte-count. Then no limit would be needed. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: Fixed refcounting/locking when attempting read error correction ↵NeilBrown2006-05-01
| | | | | | | | | | | | in raid10 We need to hold a reference to rdevs while reading and writing to attempt to correct read errors. This reference must be taken under an rcu lock. Signed-off-by: Neil Brown <neilb@suse.de> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: Avoid oops when attempting to fix read errors on raid10NeilBrown2006-05-01
| | | | | | | | | | We should add to the counter for the rdev *after* checking if the rdev is NULL!!! Signed-off-by: Neil Brown <neilb@suse.de> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* BUG_ON() Conversion in md/raid10.cEric Sesterhenn2006-04-02
| | | | | | | | this changes if() BUG(); constructs to BUG_ON() which is cleaner and can better optimized away Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [PATCH] md: Assorted little md fixesNeilBrown2006-02-03
| | | | | | | | | | | | | | - version-1 superblock + The default_bitmap_offset is in sectors, not bytes. + the 'size' field in the superblock is in sectors, not KB - raid0_run should return a negative number on error, not '1' - raid10_read_balance should not return a valid 'disk' number if ->rdev turned out to be NULL - kmem_cache_destroy doesn't like being passed a NULL. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Unlinline a bunch of other functionsArjan van de Ven2006-01-14
| | | | | | | | | | | Remove the "inline" keyword from a bunch of big functions in the kernel with the goal of shrinking it by 30kb to 40kb Signed-off-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Jeff Garzik <jgarzik@pobox.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: count corrected read errors per driveNeilBrown2006-01-06
| | | | | | | | | | Store this total in superblock (As appropriate), and make it available to userspace via sysfs. Signed-off-by: Neil Brown <neilb@suse.de> Acked-by: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: allow array level to be set textually via sysfsNeilBrown2006-01-06
| | | | | | | Signed-off-by: Neil Brown <neilb@suse.de> Acked-by: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: fix typo in commentNeilBrown2006-01-06
| | | | | | Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: define and use safe_put_page for mdNeilBrown2006-01-06
| | | | | | | | | md sometimes call put_page on NULL pointers (treating it like kfree). This is not safe, so define and use a 'safe_put_page' which checks for NULL. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: fix possible problem in raid1/raid10 error overwritingNeilBrown2006-01-06
| | | | | | | | | | | | | | The code to overwrite/reread for addressing read errors in raid1/raid10 currently assumes that the read will not alter the buffer which could be used to write to the next device. This is not a safe assumption to make. So we split the loops into a overwrite loop and a separate re-read loop, so that the writing is complete before reading is attempted. Cc: Paul Clements <paul.clements@steeleye.com> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: remove personality numbering from mdNeilBrown2006-01-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | md supports multiple different RAID level, each being implemented by a 'personality' (which is often in a separate module). These personalities have fairly artificial 'numbers'. The numbers are use to: 1- provide an index into an array where the various personalities are recorded 2- identify the module (via an alias) which implements are particular personality. Neither of these uses really justify the existence of personality numbers. The array can be replaced by a linked list which is searched (array lookup only happens very rarely). Module identification can be done using an alias based on level rather than 'personality' number. The current 'raid5' modules support two level (4 and 5) but only one personality. This slight awkwardness (which was handled in the mapping from level to personality) can be better handled by allowing raid5 to register 2 personalities. With this change in place, the core md module does not need to have an exhaustive list of all possible personalities, so other personalities can be added independently. This patch also moves the check for chunksize being non-zero into the ->run routines for the personalities that need it, rather than having it in core-md. This has a side effect of allowing 'faulty' and 'linear' not to have a chunk-size set. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: break out of a loop that doesn't need to run to completionNeilBrown2006-01-06
| | | | | | Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: convert md to use kzalloc throughoutNeilBrown2006-01-06
| | | | | | | | Replace multiple kmalloc/memset pairs with kzalloc calls. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: clean up 'page' related names in mdNeilBrown2006-01-06
| | | | | | | | | | | | | | | | | Substitute: page_cache_get -> get_page page_cache_release -> put_page PAGE_CACHE_SHIFT -> PAGE_SHIFT PAGE_CACHE_SIZE -> PAGE_SIZE PAGE_CACHE_MASK -> PAGE_MASK __free_page -> put_page because we aren't using the page cache, we are just using pages. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: raid10 read-error handling - resync and read-onlyNeilBrown2006-01-06
| | | | | | | | | | | | | | | | | | Add in correct read-error handling for resync and read-only situations. When read-only, we don't over-write, so we need to mark the failed drive in the r10_bio so we don't re-try it. During resync, we always read all blocks, so if there is a read error, we simply over-write it with the good block that we found (assuming we found one). Note that the recovery case still isn't handled in an interesting way. There is nothing useful to do for the 2-copies case. If there are 3 or more copies, then we could try reading from one of the non-missing copies, but this is a bit complicated and very rarely would be used, so I'm leaving it for now. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: auto-correct correctable read errors in raid10NeilBrown2006-01-06
| | | | | | | | Largely just a cross-port from raid1. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: support check-without-repair of raid10 arraysNeilBrown2006-01-06
| | | | | | | | Also keep count on the number of errors found. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: write intent bitmap support for raid10NeilBrown2006-01-06
| | | | | | Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: improve raid10 "IO Barrier" conceptNeilBrown2006-01-06
| | | | | | | | | | | | | raid10 needs to put up a barrier to new requests while it does resync or other background recovery. The code for this is currently open-coded, slighty obscure by its use of two waitqueues, and not documented. This patch gathers all the related code into 4 functions, and includes a comment which (hopefully) explains what is happening. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: improve read speed to raid10 arrays using 'far copies'NeilBrown2005-11-28
| | | | | | | | | | | | | | | | | | | | | | raid10 has two different layouts. One uses near-copies (so multiple copies of a block are at the same or similar offsets of different devices) and the other uses far-copies (so multiple copies of a block are stored a greatly different offsets on different devices). The point of far-copies is that it allows the first section (normally first half) to be layed out in normal raid0 style, and thus provide raid0 sequential read performance. Unfortunately, the read balancing in raid10 makes some poor decisions for far-copies arrays and you don't get the desired performance. So turn off that bad bit of read_balance for far-copies arrays. With this patch, read speed of an 'f2' array is comparable with a raid0 with the same number of devices, though write speed is ofcourse still very slow. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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