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path: root/drivers/md/raid5.c
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2008-07-14Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds
* 'for-linus' of git://git.kernel.dk/linux-2.6-block: (37 commits) splice: fix generic_file_splice_read() race with page invalidation ramfs: enable splice write drivers/block/pktcdvd.c: avoid useless memset cdrom: revert commit 22a9189 (cdrom: use kmalloced buffers instead of buffers on stack) scsi: sr avoids useless buffer allocation block: blk_rq_map_kern uses the bounce buffers for stack buffers block: add blk_queue_update_dma_pad DAC960: push down BKL pktcdvd: push BKL down into driver paride: push ioctl down into driver block: use get_unaligned_* helpers block: extend queue_flag bitops block: request_module(): use format string Add bvec_merge_data to handle stacked devices and ->merge_bvec() block: integrity flags can't use bit ops on unsigned short cmdfilter: extend default read filter sg: fix odd style (extra parenthesis) introduced by cmd filter patch block: add bounce support to blk_rq_map_user_iov cfq-iosched: get rid of enable_idle being unused warning allow userspace to modify scsi command filter on per device basis ...
2008-07-10md: ensure all blocks are uptodate or locked when syncingDan Williams
Remove the dubious attempt to prefer 'compute' over 'read'. Not only is it wrong given commit c337869d (md: do not compute parity unless it is on a failed drive), but it can trigger a BUG_ON in handle_parity_checks5(). Cc: <stable@kernel.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Neil Brown <neilb@suse.de>
2008-07-03Add bvec_merge_data to handle stacked devices and ->merge_bvec()Alasdair G Kergon
When devices are stacked, one device's merge_bvec_fn may need to perform the mapping and then call one or more functions for its underlying devices. The following bio fields are used: bio->bi_sector bio->bi_bdev bio->bi_size bio->bi_rw using bio_data_dir() This patch creates a new struct bvec_merge_data holding a copy of those fields to avoid having to change them directly in the struct bio when going down the stack only to have to change them back again on the way back up. (And then when the bio gets mapped for real, the whole exercise gets repeated, but that's a problem for another day...) Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: Neil Brown <neilb@suse.de> Cc: Milan Broz <mbroz@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-06-28Don't acknowlege that stripe-expand is complete until it really is.Neil Brown
We shouldn't acknowledge that a stripe has been expanded (When reshaping a raid5 by adding a device) until the moved data has actually been written out. However we are currently acknowledging (by calling md_done_sync) when the POST_XOR is complete and before the write. So track in s.locked whether there are pending writes, and don't call md_done_sync yet if there are. Note: we all set R5_LOCKED on devices which are are about to read from. This probably isn't technically necessary, but is usually done when writing a block, and justifies the use of s.locked here. This bug can lead to a crash if an array is stopped while an reshape is in progress. Cc: <stable@kernel.org> Signed-off-by: Neil Brown <neilb@suse.de>
2008-06-28Ensure interrupted recovery completed properly (v1 metadata plus bitmap)Neil Brown
If, while assembling an array, we find a device which is not fully in-sync with the array, it is important to set the "fullsync" flags. This is an exact analog to the setting of this flag in hot_add_disk methods. Currently, only v1.x metadata supports having devices in an array which are not fully in-sync (it keep track of how in sync they are). The 'fullsync' flag only makes a difference when a write-intent bitmap is being used. In this case it tells recovery to ignore the bitmap and recovery all blocks. This fix is already in place for raid1, but not raid5/6 or raid10. So without this fix, a raid1 ir raid4/5/6 array with version 1.x metadata and a write intent bitmaps, that is stopped in the middle of a recovery, will appear to complete the recovery instantly after it is reassembled, but the recovery will not be correct. If you might have an array like that, issueing echo repair > /sys/block/mdXX/md/sync_action will make sure recovery completes properly. Cc: <stable@kernel.org> Signed-off-by: Neil Brown <neilb@suse.de>
2008-06-06md: do not compute parity unless it is on a failed driveDan Williams
If a block is computed (rather than read) then a check/repair operation may be lead to believe that the data on disk is correct, when infact it isn't. So only compute blocks for failed devices. This issue has been around since at least 2.6.12, but has become harder to hit in recent kernels since most reads bypass the cache. echo repair > /sys/block/mdN/md/sync_action will set the parity blocks to the correct state. Cc: <stable@kernel.org> Signed-off-by: Dan Williams <dan.j.williams@intel.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>
2008-06-06md: fix prexor vs sync_request raceDan Williams
During the initial array synchronization process there is a window between when a prexor operation is scheduled to a specific stripe and when it completes for a sync_request to be scheduled to the same stripe. When this happens the prexor completes and the stripe is unconditionally marked "insync", effectively canceling the sync_request for the stripe. Prior to 2.6.23 this was not a problem because the prexor operation was done under sh->lock. The effect in older kernels being that the prexor would still erroneously mark the stripe "insync", but sync_request would be held off and re-mark the stripe as "!in_sync". Change the write completion logic to not mark the stripe "in_sync" if a prexor was performed. The effect of the change is to sometimes not set STRIPE_INSYNC. The worst this can do is cause the resync to stall waiting for STRIPE_INSYNC to be set. If this were happening, then STRIPE_SYNCING would be set and handle_issuing_new_read_requests would cause all available blocks to eventually be read, at which point prexor would never be used on that stripe any more and STRIPE_INSYNC would eventually be set. echo repair > /sys/block/mdN/md/sync_action will correct arrays that may have lost this race. Cc: <stable@kernel.org> Signed-off-by: Dan Williams <dan.j.williams@intel.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>
2008-05-24md: restart recovery cleanly after device failure.NeilBrown
When we get any IO error during a recovery (rebuilding a spare), we abort the recovery and restart it. For RAID6 (and multi-drive RAID1) it may not be best to restart at the beginning: when multiple failures can be tolerated, the recovery may be able to continue and re-doing all that has already been done doesn't make sense. We already have the infrastructure to record where a recovery is up to and restart from there, but it is not being used properly. This is because: - We sometimes abort with MD_RECOVERY_ERR rather than just MD_RECOVERY_INTR, which causes the recovery not be be checkpointed. - We remove spares and then re-added them which loses important state information. The distinction between MD_RECOVERY_ERR and MD_RECOVERY_INTR really isn't needed. If there is an error, the relevant drive will be marked as Faulty, and that is enough to ensure correct handling of the error. So we first remove MD_RECOVERY_ERR, changing some of the uses of it to MD_RECOVERY_INTR. Then we cause the attempt to remove a non-faulty device from an array to fail (unless recovery is impossible as the array is too degraded). Then when remove_and_add_spares attempts to remove the devices on which recovery can continue, it will fail, they will remain in place, and recovery will continue on them as desired. Issue: If we are halfway through rebuilding a spare and another drive fails, and a new spare is immediately available, do we want to: 1/ complete the current rebuild, then go back and rebuild the new spare or 2/ restart the rebuild from the start and rebuild both devices in parallel. Both options can be argued for. The code currently takes option 2 as a/ this requires least code change b/ this results in a minimally-degraded array in minimal time. Cc: "Eivind Sarto" <ivan@kasenna.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>
2008-05-24md: md: raid5 rate limit error printkBernd Schubert
Last night we had scsi problems and a hardware raid unit was offlined during heavy i/o. While this happened we got for about 3 minutes a huge number messages like these Apr 12 03:36:07 pfs1n14 kernel: [197510.696595] raid5:md7: read error not correctable (sector 2993096568 on sdj2). I guess the high error rate is responsible for not scheduling other events - during this time the system was not pingable and in the end also other devices run into scsi command timeouts causing problems on these unrelated devices as well. Signed-off-by: Bernd Schubert <bernd-schubert@gmx.de> Signed-off-by: Dan Williams <dan.j.williams@intel.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>
2008-05-14Remove blkdev warning triggered by using mdNeil Brown
As setting and clearing queue flags now requires that we hold a spinlock on the queue, and as blk_queue_stack_limits is called without that lock, get the lock inside blk_queue_stack_limits. For blk_queue_stack_limits to be able to find the right lock, each md personality needs to set q->queue_lock to point to the appropriate lock. Those personalities which didn't previously use a spin_lock, us q->__queue_lock. So always initialise that lock when allocated. With this in place, setting/clearing of the QUEUE_FLAG_PLUGGED bit will no longer cause warnings as it will be clear that the proper lock is held. Thanks to Dan Williams for review and fixing the silly bugs. Signed-off-by: NeilBrown <neilb@suse.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Alistair John Strachan <alistair@devzero.co.uk> Cc: Nick Piggin <npiggin@suse.de> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Jacek Luczak <difrost.kernel@gmail.com> Cc: Prakash Punnoor <prakash@punnoor.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-13md: fix raid5 'repair' operationsDan Williams
commit bd2ab67030e9116f1e4aae1289220255412b37fd "md: close a livelock window in handle_parity_checks5" introduced a bug in handling 'repair' operations. After a repair operation completes we clear the state bits tracking this operation. However, they are cleared too early and this results in the code deciding to re-run the parity check operation. Since we have done the repair in memory the second check does not find a mismatch and thus does not do a writeback. Test results: $ echo repair > /sys/block/md0/md/sync_action $ cat /sys/block/md0/md/mismatch_cnt 51072 $ echo repair > /sys/block/md0/md/sync_action $ cat /sys/block/md0/md/mismatch_cnt 0 (also fix incorrect indentation) Cc: <stable@kernel.org> Tested-by: George Spelvin <linux@horizon.com> Acked-by: NeilBrown <neilb@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30md: support blocking writes to an array on device failureDan Williams
Allows a userspace metadata handler to take action upon detecting a device failure. Based on an original patch by Neil Brown. Changes: -added blocked_wait waitqueue to rdev -don't qualify Blocked with Faulty always let userspace block writes -added md_wait_for_blocked_rdev to wait for the block device to be clear, if userspace misses the notification another one is sent every 5 seconds -set MD_RECOVERY_NEEDED after clearing "blocked" -kill DoBlock flag, just test mddev->external Signed-off-by: Dan Williams <dan.j.williams@intel.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>
2008-04-28raid: remove leading TAB on printk messagesNick Andrew
MD drivers use one printk() call to print 2 log messages and the second line may be prefixed by a TAB character. It may also output a trailing space before newline. klogd (I think) turns the TAB character into the 2 characters '^I' when logging to a file. This looks ugly. Instead of a leading TAB to indicate continuation, prefix both output lines with 'raid:' or similar. Also remove any trailing space in the vicinity of the affected code and consistently end the sentences with a period. Signed-off-by: Nick Andrew <nick@nick-andrew.net> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28md: raid5.c convert simple_strtoul to strict_strtoulDan Williams
strict_strtoul handles the open-coded sanity checks in raid5_store_stripe_cache_size and raid5_store_preread_threshold Acked-by: NeilBrown <neilb@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28md: introduce get_priority_stripe() to improve raid456 write performanceDan Williams
Improve write performance by preventing the delayed_list from dumping all its stripes onto the handle_list in one shot. Delayed stripes are now further delayed by being held on the 'hold_list'. The 'hold_list' is bypassed when: * a STRIPE_IO_STARTED stripe is found at the head of 'handle_list' * 'handle_list' is empty and i/o is being done to satisfy full stripe-width write requests * 'bypass_count' is less than 'bypass_threshold'. By default the threshold is 1, i.e. every other stripe handled is a preread stripe provided the top two conditions are false. Benchmark data: System: 2x Xeon 5150, 4x SATA, mem=1GB Baseline: 2.6.24-rc7 Configuration: mdadm --create /dev/md0 /dev/sd[b-e] -n 4 -l 5 --assume-clean Test1: dd if=/dev/zero of=/dev/md0 bs=1024k count=2048 * patched: +33% (stripe_cache_size = 256), +25% (stripe_cache_size = 512) Test2: tiobench --size 2048 --numruns 5 --block 4096 --block 131072 (XFS) * patched: +13% * patched + preread_bypass_threshold = 0: +37% Changes since v1: * reduce bypass_threshold from (chunk_size / sectors_per_chunk) to (1) and make it configurable. This defaults to fairness and modest performance gains out of the box. Changes since v2: * [neilb@suse.de]: kill STRIPE_PRIO_HI and preread_needed as they are not necessary, the important change was clearing STRIPE_DELAYED in add_stripe_bio and this has been moved out to make_request for the hang fix. * [neilb@suse.de]: simplify get_priority_stripe * [dan.j.williams@intel.com]: reset the bypass_count when ->hold_list is sampled empty (+11%) * [dan.j.williams@intel.com]: decrement the bypass_count at the detection of stripes being naturally promoted off of hold_list +2%. Note, resetting bypass_count instead of decrementing on these events yields +4% but that is probably too aggressive. Changes since v3: * cosmetic fixups Tested-by: James W. Laferriere <babydr@baby-dragons.com> Signed-off-by: Dan Williams <dan.j.williams@intel.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>
2008-04-28md: replace remaining __FUNCTION__ occurrencesHarvey Harrison
__FUNCTION__ is gcc-specific, use __func__ Signed-off-by: Harvey Harrison <harvey.harrison@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>
2008-04-11md: close a livelock window in handle_parity_checks5Dan Williams
If a failure is detected after a parity check operation has been initiated, but before it completes handle_parity_checks5 will never quiesce operations on the stripe. Explicitly handle this case by "canceling" the parity check, i.e. clear the STRIPE_OP_CHECK flags and queue the stripe on the handle list again to refresh any non-uptodate blocks. Kernel versions >= 2.6.23 are susceptible. Cc: <stable@kernel.org> Cc: NeilBrown <neilb@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-19drivers/md/raid5.c: fix printk warningsAndrew Morton
gcc-3.4.5 on sparc64: drivers/md/raid5.c: In function `raid5_end_read_request': drivers/md/raid5.c:1147: warning: long long unsigned int format, long unsigned int arg (arg 4) drivers/md/raid5.c:1164: warning: long long unsigned int format, long unsigned int arg (arg 3) drivers/md/raid5.c:1170: warning: long long unsigned int format, long unsigned int arg (arg 3) sector_t is u64, and we don't know what type the architecture uses to implement u64 (on some it is unsigned long). Cc: Neil Brown <neilb@suse.de> Cc: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06md: fix an occasional deadlock in raid5NeilBrown
raid5's 'make_request' function calls generic_make_request on underlying devices and if we run out of stripe heads, it could end up waiting for one of those requests to complete. This is bad as recursive calls to generic_make_request go on a queue and are not even attempted until make_request completes. So: don't make any generic_make_request calls in raid5 make_request until all waiting has been done. We do this by simply setting STRIPE_HANDLE instead of calling handle_stripe(). If we need more stripe_heads, raid5d will get called to process the pending stripe_heads which will call generic_make_request from a This change by itself causes a performance hit. So add a change so that raid5_activate_delayed is only called at unplug time, never in raid5. This seems to bring back the performance numbers. Calling it in raid5d was sometimes too soon... Neil said: How about we queue it for 2.6.25-rc1 and then about when -rc2 comes out, we queue it for 2.6.24.y? Acked-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Neil Brown <neilb@suse.de> Tested-by: dean gaudet <dean@arctic.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06md: change ITERATE_RDEV to rdev_for_eachNeilBrown
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>
2008-02-06md: allow a maximum extent to be set for resyncingNeilBrown
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>
2008-02-06md: Update md bitmap during resync.NeilBrown
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>
2008-01-08md: fix data corruption when a degraded raid5 array is reshapedDan Williams
We currently do not wait for the block from the missing device to be computed from parity before copying data to the new stripe layout. The change in the raid6 code is not techincally needed as we don't delay data block recovery in the same way for raid6 yet. But making the change now is safer long-term. This bug exists in 2.6.23 and 2.6.24-rc Cc: <stable@kernel.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-11-14raid5: fix unending write sequenceDan Williams
<debug output from Joel's system> handling stripe 7629696, state=0x14 cnt=1, pd_idx=2 ops=0:0:0 check 5: state 0x6 toread 0000000000000000 read 0000000000000000 write fffff800ffcffcc0 written 0000000000000000 check 4: state 0x6 toread 0000000000000000 read 0000000000000000 write fffff800fdd4e360 written 0000000000000000 check 3: state 0x1 toread 0000000000000000 read 0000000000000000 write 0000000000000000 written 0000000000000000 check 2: state 0x1 toread 0000000000000000 read 0000000000000000 write 0000000000000000 written 0000000000000000 check 1: state 0x6 toread 0000000000000000 read 0000000000000000 write fffff800ff517e40 written 0000000000000000 check 0: state 0x6 toread 0000000000000000 read 0000000000000000 write fffff800fd4cae60 written 0000000000000000 locked=4 uptodate=2 to_read=0 to_write=4 failed=0 failed_num=0 for sector 7629696, rmw=0 rcw=0 </debug> These blocks were prepared to be written out, but were never handled in ops_run_biodrain(), so they remain locked forever. The operations flags are all clear which means handle_stripe() thinks nothing else needs to be done. This state suggests that the STRIPE_OP_PREXOR bit was sampled 'set' when it should not have been. This patch cleans up cases where the code looks at sh->ops.pending when it should be looking at the consistent stack-based snapshot of the operations flags. Report from Joel: Resync done. Patch fix this bug. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Joel Bertrand <joel.bertrand@systella.fr> Cc: <stable@kernel.org> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-11-09Add UNPLUG traces to all appropriate placesAlan D. Brunelle
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>
2007-11-05md: fix misapplied patch in raid5.cNeil Brown
commit 4ae3f847e49e3787eca91bced31f8fd328d50496 ("md: raid5: fix clearing of biofill operations") did not get applied correctly, presumably due to substantial similarities between handle_stripe5 and handle_stripe6. This patch moves the chunk of new code from handle_stripe6 (where it isn't needed (yet)) to handle_stripe5. Signed-off-by: Neil Brown <neilb@suse.de> Cc: "Dan Williams" <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-23md: raid5: fix clearing of biofill operationsDan Williams
ops_complete_biofill() runs outside of spin_lock(&sh->lock) and clears the 'pending' and 'ack' bits. Since the test_and_ack_op() macro only checks against 'complete' it can get an inconsistent snapshot of pending work. Move the clearing of these bits to handle_stripe5(), under the lock. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Joel Bertrand <joel.bertrand@systella.fr> Signed-off-by: Neil Brown <neilb@suse.de> Cc: Stable <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16block: convert blkdev_issue_flush() to use empty barriersJens Axboe
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>
2007-10-10Drop 'size' argument from bio_endio and bi_end_ioNeilBrown
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>
2007-09-24raid5: fix 2 bugs in ops_complete_biofillDan Williams
1/ ops_complete_biofill tried to avoid calling handle_stripe since all the state necessary to return read completions is available. However the process of determining whether more read requests are pending requires locking the stripe (to block add_stripe_bio from updating dev->toead). ops_complete_biofill can run in tasklet context, so rather than upgrading all the stripe locks from spin_lock to spin_lock_bh this patch just unconditionally reschedules handle_stripe after completing the read request. 2/ ops_complete_biofill needlessly qualified processing R5_Wantfill with dev->toread. The result being that the 'biofill' pending bit is cleared before handling the pending read-completions on dev->read. R5_Wantfill can be unconditionally handled because the 'biofill' pending bit prevents new R5_Wantfill requests from being seen by ops_run_biofill and ops_complete_biofill. Found-by: Yuri Tikhonov <yur@emcraft.com> [neilb@suse.de: simpler fix for bug 1 than moving code] Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2007-09-11md: fix some bugs with growing raid5/raid6 arrays.NeilBrown
The recent changed to raid5 to allow offload of parity calculation etc introduced some bugs in the code for growing (i.e. adding a disk to) raid5 and raid6. This fixes them Acked-by: Dan Williams <dan.j.williams@intel.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>
2007-07-24[BLOCK] Get rid of request_queue_t typedefJens Axboe
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>
2007-07-20async_tx: fix kmap_atomic usage in async_memcpyDan Williams
Andrew Morton: [async_memcpy] is very wrong if both ASYNC_TX_KMAP_DST and ASYNC_TX_KMAP_SRC can ever be set. We'll end up using the same kmap slot for both src add dest and we get either corrupted data or a BUG. Evgeniy Polyakov: Btw, shouldn't it always be kmap_atomic() even if flag is not set. That pages are usual one returned by alloc_page(). So fix the usage of kmap_atomic and kill the ASYNC_TX_KMAP_DST and ASYNC_TX_KMAP_SRC flags. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-20mm: Remove slab destructors from kmem_cache_create().Paul Mundt
Slab destructors were no longer supported after Christoph's c59def9f222d44bb7e2f0a559f2906191a0862d7 change. They've been BUGs for both slab and slub, and slob never supported them either. This rips out support for the dtor pointer from kmem_cache_create() completely and fixes up every single callsite in the kernel (there were about 224, not including the slab allocator definitions themselves, or the documentation references). Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-07-13md: remove raid5 compute_block and compute_parity5Dan Williams
replaced by raid5_run_ops Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-By: NeilBrown <neilb@suse.de>
2007-07-13md: handle_stripe5 - request io processing in raid5_run_opsDan Williams
I/O submission requests were already handled outside of the stripe lock in handle_stripe. Now that handle_stripe is only tasked with finding work, this logic belongs in raid5_run_ops. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-By: NeilBrown <neilb@suse.de>
2007-07-13md: handle_stripe5 - add request/completion logic for async expand opsDan Williams
When a stripe is being expanded bulk copying takes place to move the data from the old stripe to the new. Since raid5_run_ops only operates on one stripe at a time these bulk copies are handled in-line under the stripe lock. In the dma offload case we poll for the completion of the operation. After the data has been copied into the new stripe the parity needs to be recalculated across the new disks. We reuse the existing postxor functionality to carry out this calculation. By setting STRIPE_OP_POSTXOR without setting STRIPE_OP_BIODRAIN the completion path in handle stripe can differentiate expand operations from normal write operations. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-By: NeilBrown <neilb@suse.de>
2007-07-13md: handle_stripe5 - add request/completion logic for async read opsDan Williams
When a read bio is attached to the stripe and the corresponding block is marked R5_UPTODATE, then a read (biofill) operation is scheduled to copy the data from the stripe cache to the bio buffer. handle_stripe flags the blocks to be operated on with the R5_Wantfill flag. If new read requests arrive while raid5_run_ops is running they will not be handled until handle_stripe is scheduled to run again. Changelog: * cleanup to_read and to_fill accounting * do not fail reads that have reached the cache Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-By: NeilBrown <neilb@suse.de>
2007-07-13md: handle_stripe5 - add request/completion logic for async check opsDan Williams
Check operations are scheduled when the array is being resynced or an explicit 'check/repair' command was sent to the array. Previously check operations would destroy the parity block in the cache such that even if parity turned out to be correct the parity block would be marked !R5_UPTODATE at the completion of the check. When the operation can be carried out by a dma engine the assumption is that it can check parity as a read-only operation. If raid5_run_ops notices that the check was handled by hardware it will preserve the R5_UPTODATE status of the parity disk. When a check operation determines that the parity needs to be repaired we reuse the existing compute block infrastructure to carry out the operation. Repair operations imply an immediate write back of the data, so to differentiate a repair from a normal compute operation the STRIPE_OP_MOD_REPAIR_PD flag is added. Changelog: * remove test_and_set/test_and_clear BUG_ONs, Neil Brown Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-By: NeilBrown <neilb@suse.de>
2007-07-13md: handle_stripe5 - add request/completion logic for async compute opsDan Williams
handle_stripe will compute a block when a backing disk has failed, or when it determines it can save a disk read by computing the block from all the other up-to-date blocks. Previously a block would be computed under the lock and subsequent logic in handle_stripe could use the newly up-to-date block. With the raid5_run_ops implementation the compute operation is carried out a later time outside the lock. To preserve the old functionality we take advantage of the dependency chain feature of async_tx to flag the block as R5_Wantcompute and then let other parts of handle_stripe operate on the block as if it were up-to-date. raid5_run_ops guarantees that the block will be ready before it is used in another operation. However, this only works in cases where the compute and the dependent operation are scheduled at the same time. If a previous call to handle_stripe sets the R5_Wantcompute flag there is no facility to pass the async_tx dependency chain across successive calls to raid5_run_ops. The req_compute variable protects against this case. Changelog: * remove the req_compute BUG_ON Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-By: NeilBrown <neilb@suse.de>
2007-07-13md: handle_stripe5 - add request/completion logic for async write opsDan Williams
After handle_stripe5 decides whether it wants to perform a read-modify-write, or a reconstruct write it calls handle_write_operations5. A read-modify-write operation will perform an xor subtraction of the blocks marked with the R5_Wantprexor flag, copy the new data into the stripe (biodrain) and perform a postxor operation across all up-to-date blocks to generate the new parity. A reconstruct write is run when all blocks are already up-to-date in the cache so all that is needed is a biodrain and postxor. On the completion path STRIPE_OP_PREXOR will be set if the operation was a read-modify-write. The STRIPE_OP_BIODRAIN flag is used in the completion path to differentiate write-initiated postxor operations versus expansion-initiated postxor operations. Completion of a write triggers i/o to the drives. Changelog: * make the 'rcw' parameter to handle_write_operations5 a simple flag, Neil Brown * remove test_and_set/test_and_clear BUG_ONs, Neil Brown Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-By: NeilBrown <neilb@suse.de>
2007-07-13md: common infrastructure for running operations with raid5_run_opsDan Williams
All the handle_stripe operations that are to be transitioned to use raid5_run_ops need a method to coherently gather work under the stripe-lock and hand that work off to raid5_run_ops. The 'get_stripe_work' routine runs under the lock to read all the bits in sh->ops.pending that do not have the corresponding bit set in sh->ops.ack. This modified 'pending' bitmap is then passed to raid5_run_ops for processing. The transition from 'ack' to 'completion' does not need similar protection as the existing release_stripe infrastructure will guarantee that handle_stripe will run again after a completion bit is set, and handle_stripe can tolerate a sh->ops.completed bit being set while the lock is held. A call to async_tx_issue_pending_all() is added to raid5d to kick the offload engines once all pending stripe operations work has been submitted. This enables batching of the submission and completion of operations. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-By: NeilBrown <neilb@suse.de>
2007-07-13md: raid5_run_ops - run stripe operations outside sh->lockDan Williams
When the raid acceleration work was proposed, Neil laid out the following attack plan: 1/ move the xor and copy operations outside spin_lock(&sh->lock) 2/ find/implement an asynchronous offload api The raid5_run_ops routine uses the asynchronous offload api (async_tx) and the stripe_operations member of a stripe_head to carry out xor+copy operations asynchronously, outside the lock. To perform operations outside the lock a new set of state flags is needed to track new requests, in-flight requests, and completed requests. In this new model handle_stripe is tasked with scanning the stripe_head for work, updating the stripe_operations structure, and finally dropping the lock and calling raid5_run_ops for processing. The following flags outline the requests that handle_stripe can make of raid5_run_ops: STRIPE_OP_BIOFILL - copy data into request buffers to satisfy a read request STRIPE_OP_COMPUTE_BLK - generate a missing block in the cache from the other blocks STRIPE_OP_PREXOR - subtract existing data as part of the read-modify-write process STRIPE_OP_BIODRAIN - copy data out of request buffers to satisfy a write request STRIPE_OP_POSTXOR - recalculate parity for new data that has entered the cache STRIPE_OP_CHECK - verify that the parity is correct STRIPE_OP_IO - submit i/o to the member disks (note this was already performed outside the stripe lock, but it made sense to add it as an operation type The flow is: 1/ handle_stripe sets STRIPE_OP_* in sh->ops.pending 2/ raid5_run_ops reads sh->ops.pending, sets sh->ops.ack, and submits the operation to the async_tx api 3/ async_tx triggers the completion callback routine to set sh->ops.complete and release the stripe 4/ handle_stripe runs again to finish the operation and optionally submit new operations that were previously blocked Note this patch just defines raid5_run_ops, subsequent commits (one per major operation type) modify handle_stripe to take advantage of this routine. Changelog: * removed ops_complete_biodrain in favor of ops_complete_postxor and ops_complete_write. * removed the raid5_run_ops workqueue * call bi_end_io for reads in ops_complete_biofill, saves a call to handle_stripe * explicitly handle the 2-disk raid5 case (xor becomes memcpy), Neil Brown * fix race between async engines and bi_end_io call for reads, Neil Brown * remove unnecessary spin_lock from ops_complete_biofill * remove test_and_set/test_and_clear BUG_ONs, Neil Brown * remove explicit interrupt handling for channel switching, this feature was absorbed (i.e. it is now implicit) by the async_tx api * use return_io in ops_complete_biofill Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-By: NeilBrown <neilb@suse.de>
2007-07-13raid5: replace custom debug PRINTKs with standard pr_debugDan Williams
Replaces PRINTK with pr_debug, and kills the RAID5_DEBUG definition in favor of the global DEBUG definition. To get local debug messages just add '#define DEBUG' to the top of the file. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-By: NeilBrown <neilb@suse.de>
2007-07-13raid5: refactor handle_stripe5 and handle_stripe6 (v3)Dan Williams
handle_stripe5 and handle_stripe6 have very deep logic paths handling the various states of a stripe_head. By introducing the 'stripe_head_state' and 'r6_state' objects, large portions of the logic can be moved to sub-routines. 'struct stripe_head_state' consumes all of the automatic variables that previously stood alone in handle_stripe5,6. 'struct r6_state' contains the handle_stripe6 specific variables like p_failed and q_failed. One of the nice side effects of the 'stripe_head_state' change is that it allows for further reductions in code duplication between raid5 and raid6. The following new routines are shared between raid5 and raid6: handle_completed_write_requests handle_requests_to_failed_array handle_stripe_expansion Changes: * v2: fixed 'conf->raid_disk-1' for the raid6 'handle_stripe_expansion' path * v3: removed the unused 'dirty' field from struct stripe_head_state * v3: coalesced open coded bi_end_io routines into return_io() Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-By: NeilBrown <neilb@suse.de>
2007-07-13async_tx: add the async_tx apiDan Williams
The async_tx api provides methods for describing a chain of asynchronous bulk memory transfers/transforms with support for inter-transactional dependencies. It is implemented as a dmaengine client that smooths over the details of different hardware offload engine implementations. Code that is written to the api can optimize for asynchronous operation and the api will fit the chain of operations to the available offload resources. I imagine that any piece of ADMA hardware would register with the 'async_*' subsystem, and a call to async_X would be routed as appropriate, or be run in-line. - Neil Brown async_tx exploits the capabilities of struct dma_async_tx_descriptor to provide an api of the following general format: struct dma_async_tx_descriptor * async_<operation>(..., struct dma_async_tx_descriptor *depend_tx, dma_async_tx_callback cb_fn, void *cb_param) { struct dma_chan *chan = async_tx_find_channel(depend_tx, <operation>); struct dma_device *device = chan ? chan->device : NULL; int int_en = cb_fn ? 1 : 0; struct dma_async_tx_descriptor *tx = device ? device->device_prep_dma_<operation>(chan, len, int_en) : NULL; if (tx) { /* run <operation> asynchronously */ ... tx->tx_set_dest(addr, tx, index); ... tx->tx_set_src(addr, tx, index); ... async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param); } else { /* run <operation> synchronously */ ... <operation> ... async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param); } return tx; } async_tx_find_channel() returns a capable channel from its pool. The channel pool is organized as a per-cpu array of channel pointers. The async_tx_rebalance() routine is tasked with managing these arrays. In the uniprocessor case async_tx_rebalance() tries to spread responsibility evenly over channels of similar capabilities. For example if there are two copy+xor channels, one will handle copy operations and the other will handle xor. In the SMP case async_tx_rebalance() attempts to spread the operations evenly over the cpus, e.g. cpu0 gets copy channel0 and xor channel0 while cpu1 gets copy channel 1 and xor channel 1. When a dependency is specified async_tx_find_channel defaults to keeping the operation on the same channel. A xor->copy->xor chain will stay on one channel if it supports both operation types, otherwise the transaction will transition between a copy and a xor resource. Currently the raid5 implementation in the MD raid456 driver has been converted to the async_tx api. A driver for the offload engines on the Intel Xscale series of I/O processors, iop-adma, is provided in a later commit. With the iop-adma driver and async_tx, raid456 is able to offload copy, xor, and xor-zero-sum operations to hardware engines. On iop342 tiobench showed higher throughput for sequential writes (20 - 30% improvement) and sequential reads to a degraded array (40 - 55% improvement). For the other cases performance was roughly equal, +/- a few percentage points. On a x86-smp platform the performance of the async_tx implementation (in synchronous mode) was also +/- a few percentage points of the original implementation. According to 'top' on iop342 CPU utilization drops from ~50% to ~15% during a 'resync' while the speed according to /proc/mdstat doubles from ~25 MB/s to ~50 MB/s. The tiobench command line used for testing was: tiobench --size 2048 --block 4096 --block 131072 --dir /mnt/raid --numruns 5 * iop342 had 1GB of memory available Details: * if CONFIG_DMA_ENGINE=n the asynchronous path is compiled away by making async_tx_find_channel a static inline routine that always returns NULL * when a callback is specified for a given transaction an interrupt will fire at operation completion time and the callback will occur in a tasklet. if the the channel does not support interrupts then a live polling wait will be performed * the api is written as a dmaengine client that requests all available channels * In support of dependencies the api implicitly schedules channel-switch interrupts. The interrupt triggers the cleanup tasklet which causes pending operations to be scheduled on the next channel * Xor engines treat an xor destination address differently than a software xor routine. To the software routine the destination address is an implied source, whereas engines treat it as a write-only destination. This patch modifies the xor_blocks routine to take a an explicit destination address to mirror the hardware. Changelog: * fixed a leftover debug print * don't allow callbacks in async_interrupt_cond * fixed xor_block changes * fixed usage of ASYNC_TX_XOR_DROP_DEST * drop dma mapping methods, suggested by Chris Leech * printk warning fixups from Andrew Morton * don't use inline in C files, Adrian Bunk * select the API when MD is enabled * BUG_ON xor source counts <= 1 * implicitly handle hardware concerns like channel switching and interrupts, Neil Brown * remove the per operation type list, and distribute operation capabilities evenly amongst the available channels * simplify async_tx_find_channel to optimize the fast path * introduce the channel_table_initialized flag to prevent early calls to the api * reorganize the code to mimic crypto * include mm.h as not all archs include it in dma-mapping.h * make the Kconfig options non-user visible, Adrian Bunk * move async_tx under crypto since it is meant as 'core' functionality, and the two may share algorithms in the future * move large inline functions into c files * checkpatch.pl fixes * gpl v2 only correction Cc: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-By: NeilBrown <neilb@suse.de>
2007-07-13xor: make 'xor_blocks' a library routine for use with async_txDan Williams
The async_tx api tries to use a dma engine for an operation, but will fall back to an optimized software routine otherwise. Xor support is implemented using the raid5 xor routines. For organizational purposes this routine is moved to a common area. The following fixes are also made: * rename xor_block => xor_blocks, suggested by Adrian Bunk * ensure that xor.o initializes before md.o in the built-in case * checkpatch.pl fixes * mark calibrate_xor_blocks __init, Adrian Bunk Cc: Adrian Bunk <bunk@stusta.de> Cc: NeilBrown <neilb@suse.de> Cc: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2007-05-09Revert "md: improve partition detection in md array"Linus Torvalds
This reverts commit 5b479c91da90eef605f851508744bfe8269591a0. Quoth Neil Brown: "It causes an oops when auto-detecting raid arrays, and it doesn't seem easy to fix. The array may not be 'open' when do_md_run is called, so bdev->bd_disk might be NULL, so bd_set_size can oops. This whole approach of opening an md device before it has been assembled just seems to get more and more painful. I think I'm going to have to come up with something clever to provide both backward comparability with usage expectation, and sane integration into the rest of the kernel." Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09md: improve partition detection in md arrayNeilBrown
md currently uses ->media_changed to make sure rescan_partitions is call on md array after they are assembled. However that doesn't happen until the array is opened, which is later than some people would like. So use blkdev_ioctl to do the rescan immediately that the array has been assembled. This means we can remove all the ->change infrastructure as it was only used to trigger a partition rescan. 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>
2007-05-09md: remove the slash from the name of a kmem_cache used by raid5NeilBrown
SLUB doesn't like slashes as it wants to use the cache name as the name of a directory (or symlink) in sysfs. Signed-off-by: Neil Brown <neilb@suse.de> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>