linux/drivers/md, branch v2.6.37

Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

2010-12-20T17:19:46Z

* 'for-linus' of git://git.kernel.dk/linux-2.6-block: cciss: fix cciss_revalidate panic block: max hardware sectors limit wrapper block: Deprecate QUEUE_FLAG_CLUSTER and use queue_limits instead blk-throttle: Correct the placement of smp_rmb() blk-throttle: Trim/adjust slice_end once a bio has been dispatched block: check for proper length of iov entries earlier in blk_rq_map_user_iov() drbd: fix for spin_lock_irqsave in endio callback drbd: don't recvmsg with zero length

block: max hardware sectors limit wrapper

2010-12-17T07:36:01Z

Implement blk_limits_max_hw_sectors() and make blk_queue_max_hw_sectors() a wrapper around it. DM needs this to avoid setting queue_limits' max_hw_sectors and max_sectors directly. dm_set_device_limits() now leverages blk_limits_max_hw_sectors() logic to establish the appropriate max_hw_sectors minimum (PAGE_SIZE). Fixes issue where DM was incorrectly setting max_sectors rather than max_hw_sectors (which caused dm_merge_bvec()'s max_hw_sectors check to be ineffective). Signed-off-by: Mike Snitzer Cc: stable@kernel.org Acked-by: Martin K. Petersen Signed-off-by: Jens Axboe

block: Deprecate QUEUE_FLAG_CLUSTER and use queue_limits instead

2010-12-17T07:35:53Z

When stacking devices, a request_queue is not always available. This forced us to have a no_cluster flag in the queue_limits that could be used as a carrier until the request_queue had been set up for a metadevice. There were several problems with that approach. First of all it was up to the stacking device to remember to set queue flag after stacking had completed. Also, the queue flag and the queue limits had to be kept in sync at all times. We got that wrong, which could lead to us issuing commands that went beyond the max scatterlist limit set by the driver. The proper fix is to avoid having two flags for tracking the same thing. We deprecate QUEUE_FLAG_CLUSTER and use the queue limit directly in the block layer merging functions. The queue_limit 'no_cluster' is turned into 'cluster' to avoid double negatives and to ease stacking. Clustering defaults to being enabled as before. The queue flag logic is removed from the stacking function, and explicitly setting the cluster flag is no longer necessary in DM and MD. Reported-by: Ed Lin Signed-off-by: Martin K. Petersen Acked-by: Mike Snitzer Cc: stable@kernel.org Signed-off-by: Jens Axboe

md: protect against NULL reference when waiting to start a raid10.

2010-12-09T06:02:14Z

When we fail to start a raid10 for some reason, we call md_unregister_thread to kill the thread that was created. Unfortunately md_thread() will then make one call into the handler (raid10d) even though md_wakeup_thread has not been called. This is not safe and as md_unregister_thread is called after mddev->private has been set to NULL, it will definitely cause a NULL dereference. So fix this at both ends: - md_thread should only call the handler if THREAD_WAKEUP has been set. - raid10 should call md_unregister_thread before setting things to NULL just like all the other raid modules do. This is applicable to 2.6.35 and later. Cc: stable@kernel.org Reported-by: "Citizen" Signed-off-by: NeilBrown

md: fix bug with re-adding of partially recovered device.

2010-12-09T05:36:28Z

With v0.90 metadata, a hot-spare does not become a full member of the array until recovery is complete. So if we re-add such a device to the array, we know that all of it is as up-to-date as the event count would suggest, and so it a bitmap-based recovery is possible. However with v1.x metadata, the hot-spare immediately becomes a full member of the array, but it record how much of the device has been recovered. If the array is stopped and re-assembled recovery starts from this point. When such a device is hot-added to an array we currently lose the 'how much is recovered' information and incorrectly included it as a full in-sync member (after bitmap-based fixup). This is wrong and unsafe and could corrupt data. So be more careful about setting saved_raid_disk - which is what guides the re-adding of devices back into an array. The new code matches the code in slot_store which does a similar thing, which is encouraging. This is suitable for any -stable kernel. Reported-by: "Dailey, Nate" Cc: stable@kernel.org Signed-off-by: NeilBrown

md: fix possible deadlock in handling flush requests.

2010-12-09T05:17:51Z

As recorded in https://bugzilla.kernel.org/show_bug.cgi?id=24012 it is possible for a flush request through md to hang. This is due to an interaction between the recursion avoidance in generic_make_request, the insistence in md of only having one flush active at a time, and the possibility of dm (or md) submitting two flush requests to a device from the one generic_make_request. If a generic_make_request call into dm causes two flush requests to be queued (as happens if the dm table has two targets - they get one each), these two will be queued inside generic_make_request. Assume they are for the same md device. The first is processed and causes 1 or more flush requests to be sent to lower devices. These get queued within generic_make_request too. Then the second flush to the md device gets handled and it blocks waiting for the first flush to complete. But it won't complete until the two lower-device requests complete, and they haven't even been submitted yet as they are on the generic_make_request queue. The deadlock can be broken by using a separate thread to submit the requests to lower devices. md has such a thread readily available: md_wq. So use it to submit these requests. Reported-by: Giacomo Catenazzi Tested-by: Giacomo Catenazzi Signed-off-by: NeilBrown

md: move code in to submit_flushes.

2010-12-09T05:04:25Z

submit_flushes is called from exactly one place. Move the code that is before and after that call into submit_flushes. This has not functional change, but will make the next patch smaller and easier to follow. Signed-off-by: NeilBrown

md: remove handling of flush_pending in md_submit_flush_data

2010-12-09T04:59:01Z

None of the functions called between setting flush_pending to 1, and atomic_dec_and_test can change flush_pending, or will anything running in any other thread (as ->flush_bio is not NULL). So the atomic_dec_and_test will always succeed. So remove the atomic_sec and the atomic_dec_and_test. Signed-off-by: NeilBrown

md: Call blk_queue_flush() to establish flush/fua support

2010-11-24T05:40:33Z

Before 2.6.37, the md layer had a mechanism for catching I/Os with the barrier flag set, and translating the barrier into barriers for all the underlying devices. With 2.6.37, I/O barriers have become plain old flushes, and the md code was updated to reflect this. However, one piece was left out -- the md layer does not tell the block layer that it supports flushes or FUA access at all, which results in md silently dropping flush requests. Since the support already seems there, just add this one piece of bookkeeping. Signed-off-by: Darrick J. Wong Signed-off-by: NeilBrown

md/raid1: really fix recovery looping when single good device fails.

2010-11-24T05:39:46Z

Commit 4044ba58dd15cb01797c4fd034f39ef4a75f7cc3 supposedly fixed a problem where if a raid1 with just one good device gets a read-error during recovery, the recovery would abort and immediately restart in an infinite loop. However it depended on raid1_remove_disk removing the spare device from the array. But that does not happen in this case. So add a test so that in the 'recovery_disabled' case, the device will be removed. This suitable for any kernel since 2.6.29 which is when recovery_disabled was introduced. Cc: stable@kernel.org Reported-by: Sebastian Färber Signed-off-by: NeilBrown