linux/drivers/md, branch v2.6.38

md: Fix - again - partition detection when array becomes active

2011-02-24T06:26:41Z

Revert b821eaa572fd737faaf6928ba046e571526c36c6 and f3b99be19ded511a1bf05a148276239d9f13eefa When I wrote the first of these I had a wrong idea about the lifetime of 'struct block_device'. It can disappear at any time that the block device is not open if it falls out of the inode cache. So relying on the 'size' recorded with it to detect when the device size has changed and so we need to revalidate, is wrong. Rather, we really do need the 'changed' attribute stored directly in the mddev and set/tested as appropriate. Without this patch, a sequence of: mknod / open / close / unlink (which can cause a block_device to be created and then destroyed) will result in a rescan of the partition table and consequence removal and addition of partitions. Several of these in a row can get udev racing to create and unlink and other code can get confused. With the patch, the rescan is only performed when needed and so there are no races. This is suitable for any stable kernel from 2.6.35. Reported-by: "Wojcik, Krzysztof" Signed-off-by: NeilBrown Cc: stable@kernel.org

md: avoid spinlock problem in blk_throtl_exit

2011-02-21T07:25:57Z

blk_throtl_exit assumes that ->queue_lock still exists, so make sure that it does. To do this, we stop redirecting ->queue_lock to conf->device_lock and leave it pointing where it is initialised - __queue_lock. As the blk_plug functions check the ->queue_lock is held, we now take that spin_lock explicitly around the plug functions. We don't need the locking, just the warning removal. This is needed for any kernel with the blk_throtl code, which is which is 2.6.37 and later. Cc: stable@kernel.org Signed-off-by: NeilBrown

md: correctly handle probe of an 'mdp' device.

2011-02-16T02:58:51Z

'mdp' devices are md devices with preallocated device numbers for partitions. As such it is possible to mknod and open a partition before opening the whole device. this causes md_probe() to be called with a device number of a partition, which in-turn calls mddev_find with such a number. However mddev_find expects the number of a 'whole device' and does the wrong thing with partition numbers. So add code to mddev_find to remove the 'partition' part of a device number and just work with the 'whole device'. This patch addresses https://bugzilla.kernel.org/show_bug.cgi?id=28652 Reported-by: hkmaly@bigfoot.com Signed-off-by: NeilBrown Cc:

md: don't set_capacity before array is active.

2011-02-16T02:58:38Z

If the desired size of an array is set (via sysfs) before the array is active (which is the normal sequence), we currrently call set_capacity immediately. This means that a subsequent 'open' (as can be caused by some udev-triggers program) will notice the new size and try to probe for partitions. However as the array isn't quite ready yet the read will fail. Then when the array is read, as the size doesn't change again we don't try to re-probe. So when setting array size via sysfs, only call set_capacity if the array is already active. Signed-off-by: NeilBrown

md: Fix raid1->raid0 takeover

2011-02-13T23:01:41Z

Takeover raid1->raid0 not succeded. Kernel message is shown: "md/raid0:md126: too few disks (1 of 2) - aborting!" Problem was that we weren't updating ->raid_disks for that takeover, unlike all the others. Signed-off-by: Krzysztof Wojcik Signed-off-by: NeilBrown

FIX: md: process hangs at wait_barrier after 0->10 takeover

2011-02-08T00:49:02Z

Following symptoms were observed: 1. After raid0->raid10 takeover operation we have array with 2 missing disks. When we add disk for rebuild, recovery process starts as expected but it does not finish- it stops at about 90%, md126_resync process hangs in "D" state. 2. Similar behavior is when we have mounted raid0 array and we execute takeover to raid10. After this when we try to unmount array- it causes process umount hangs in "D" In scenarios above processes hang at the same function- wait_barrier in raid10.c. Process waits in macro "wait_event_lock_irq" until the "!conf->barrier" condition will be true. In scenarios above it never happens. Reason was that at the end of level_store, after calling pers->run, we call mddev_resume. This calls pers->quiesce(mddev, 0) with RAID10, that calls lower_barrier. However raise_barrier hadn't been called on that 'conf' yet, so conf->barrier becomes negative, which is bad. This patch introduces setting conf->barrier=1 after takeover operation. It prevents to become barrier negative after call lower_barrier(). Signed-off-by: Krzysztof Wojcik Signed-off-by: NeilBrown

md_make_request: don't touch the bio after calling make_request

2011-02-07T22:53:28Z

md_make_request was calling bio_sectors() for part_stat_add after it was calling the make_request function. This is bad because the make_request function can free the bio and because the bi_size field can change around. The fix here was suggested by Jens Axboe. It saves the sector count before the make_request call. I hit this with CONFIG_DEBUG_PAGEALLOC turned on while trying to break his pretty fusionio card. Cc: Signed-off-by: Chris Mason Signed-off-by: NeilBrown

md: Don't allow slot_store while resync/recovery is happening.

2011-02-02T00:57:13Z

Activating a spare in an array while resync/recovery is already happening can lead the that spare being marked in-sync when it isn't really. So don't allow the 'slot' to be set (this activating the device) while resync/recovery is happening. Signed-off-by: NeilBrown

md: don't clear curr_resync_completed at end of resync.

2011-01-31T03:30:27Z

There is no need to set this to zero at this point. It will be set to zero by remove_and_add_spares or at the start of md_do_sync at the latest. And setting it to zero before MD_RECOVERY_RUNNING is cleared can make a 'zero' appear briefly in the 'sync_completed' sysfs attribute just as resync is finishing. So simply remove this setting to zero. Signed-off-by: NeilBrown

md: Don't use remove_and_add_spares to remove failed devices from a read-only array

2011-01-31T02:47:13Z

remove_and_add_spares is called in two places where the needs really are very different. remove_and_add_spares should not be called on an array which is about to be reshaped as some extra devices might have been manually added and that would remove them. However if the array is 'read-auto', that will currently happen, which is bad. So in the 'ro != 0' case don't call remove_and_add_spares but simply remove the failed devices as the comment suggests is needed. Signed-off-by: NeilBrown