linux/drivers/md/raid10.c, branch v3.0.86

md/raid10: Don't try to recovery unmatched (and unused) chunks.

2012-07-16T15:47:52Z

commit fc448a18ae6219af9a73257b1fbcd009efab4a81 upstream. If a RAID10 has an odd number of chunks - as might happen when there are an odd number of devices - the last chunk has no pair and so is not mirrored. We don't store data there, but when recovering the last device in an array we retry to recover that last chunk from a non-existent location. This results in an error, and the recovery aborts. When we get to that last chunk we should just stop - there is nothing more to do anyway. This bug has been present since the introduction of RAID10, so the patch is appropriate for any -stable kernel. Reported-by: Christian Balzer Tested-by: Christian Balzer Signed-off-by: NeilBrown [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

md/raid1,raid10: avoid deadlock during resync/recovery.

2012-04-02T16:27:11Z

commit d6b42dcb995e6acd7cc276774e751ffc9f0ef4bf upstream. If RAID1 or RAID10 is used under LVM or some other stacking block device, it is possible to enter a deadlock during resync or recovery. This can happen if the upper level block device creates two requests to the RAID1 or RAID10. The first request gets processed, blocks recovery and queue requests for underlying requests in current->bio_list. A resync request then starts which will wait for those requests and block new IO. But then the second request to the RAID1/10 will be attempted and it cannot progress until the resync request completes, which cannot progress until the underlying device requests complete, which are on a queue behind that second request. So allow that second request to proceed even though there is a resync request about to start. This is suitable for any -stable kernel. Reported-by: Ray Morris Tested-by: Ray Morris Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman

md: Avoid waking up a thread after it has been freed.

2011-10-16T21:14:53Z

commit 01f96c0a9922cd9919baf9d16febdf7016177a12 upstream. Two related problems: 1/ some error paths call "md_unregister_thread(mddev->thread)" without subsequently clearing ->thread. A subsequent call to mddev_unlock will try to wake the thread, and crash. 2/ Most calls to md_wakeup_thread are protected against the thread disappeared either by: - holding the ->mutex - having an active request, so something else must be keeping the array active. However mddev_unlock calls md_wakeup_thread after dropping the mutex and without any certainty of an active request, so the ->thread could theoretically disappear. So we need a spinlock to provide some protections. So change md_unregister_thread to take a pointer to the thread pointer, and ensure that it always does the required locking, and clears the pointer properly. Reported-by: "Moshe Melnikov" Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman

md/raid10: reformat some loops with less indenting.

2011-05-11T04:54:41Z

When a loop ends with an 'if' with a large body, it is neater to make the if 'continue' on the inverse condition, and then the body is indented less. Apply this pattern 3 times, and wrap some other long lines. Signed-off-by: NeilBrown

md/raid10: remove unused variable.

2011-05-11T04:54:32Z

This variable 'disk' is never used - how odd. Signed-off-by: NeilBrown

md/raid10: make more use of 'slot' in raid10d.

2011-05-11T04:54:19Z

Now that we have a 'slot' variable, make better use of it to simplify some code a little. Signed-off-by: NeilBrown

md/raid10: some tidying up in fix_read_error

2011-05-11T04:53:17Z

Currently the rdev on which a read error happened could be removed before we perform the fix_error handling. This requires extra tests for NULL. So delay the rdev_dec_pending call until after the call to fix_read_error so that we can be sure that the rdev still exists. This allows an 'if' clause to be removed so the body gets re-indented back one level. Signed-off-by: NeilBrown

md: simplify raid10 read_balance

2011-05-11T04:27:03Z

raid10 read balance has two different loop for looking through possible devices to chose the best. Collapse those into one loop and generally make the code more readable. Signed-off-by: NeilBrown

md: fix up raid1/raid10 unplugging.

2011-04-18T08:25:43Z

We just need to make sure that an unplug event wakes up the md thread, which is exactly what mddev_check_plugged does. Also remove some plug-related code that is no longer needed. Signed-off-by: NeilBrown

md: use new plugging interface for RAID IO.

2011-04-18T08:25:41Z

md/raid submits a lot of IO from the various raid threads. So adding start/finish plug calls to those so that some plugging happens. Signed-off-by: NeilBrown