kernel/linux.git/drivers/md/md.h, branch v3.0.91

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

2011-10-16T21:14:53+00:00

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: support initial bitmap creation in-kernel

2011-06-09T01:41:36+00:00

Add bitmap support to the device-mapper specific metadata area. This patch allows the creation of the bitmap metadata area upon initial array creation via device-mapper. Signed-off-by: Jonathan Brassow Signed-off-by: NeilBrown

MD: add sync_super to mddev_t struct

2011-06-08T05:11:31+00:00

Add the 'sync_super' function pointer to MD array structure (struct mddev_s) If device-mapper (dm-raid.c) is to define its own on-disk superblock and be able to load it, there must still be a way for MD to initiate superblock updates. The simplest way to make this happen is to provide a pointer in the MD array structure that can be set by device-mapper (or other module) with a function to do this. If the function has been set, it will be used; otherwise, the method with be looked up via 'super_types' as usual. Signed-off-by: Jonathan Brassow Signed-off-by: NeilBrown

md: provide generic support for handling unplug callbacks.

2011-04-18T08:25:42+00:00

When an md device adds a request to a queue, it can call mddev_check_plugged. If this succeeds then we know that the md thread will be woken up shortly, and ->plug_cnt will be non-zero until then, so some processing can be delayed. If it fails, then no unplug callback is expected and the make_request function needs to do whatever is required to make the request happen. Signed-off-by: NeilBrown

md - remove old plugging code.

2011-04-18T08:25:42+00:00

md has some plugging infrastructure for RAID5 to use because the normal plugging infrastructure required a 'request_queue', and when called from dm, RAID5 doesn't have one of those available. This relied on the ->unplug_fn callback which doesn't exist any more. So remove all of that code, both in md and raid5. Subsequent patches with restore the plugging functionality. Signed-off-by: NeilBrown

Fix common misspellings

2011-03-31T14:26:23+00:00

Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi

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

2011-02-24T06:26:41+00:00

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: Remove the AllReserved flag for component devices.

2011-01-31T01:10:09+00:00

This flag is not needed and is used badly. Devices that are included in a native-metadata array are reserved exclusively for that array - and currently have AllReserved set. They all are bd_claimed for the rdev and so cannot be shared. Devices that are included in external-metadata arrays can be shared among multiple arrays - providing there is no overlap. These are bd_claimed for md in general - not for a particular rdev. When changing the amount of a device that is used in an array we need to check for overlap. This currently includes a check on AllReserved So even without overlap, sharing with an AllReserved device is not allowed. However the bd_claim usage already precludes sharing with these devices, so the test on AllReserved is not needed. And in fact it is wrong. As this is the only use of AllReserved, simply remove all usage and definition of AllReserved. Signed-off-by: NeilBrown

md: separate meta and data devs

2011-01-13T22:14:34+00:00

Allow the metadata to be on a separate device from the data. This doesn't mean the data and metadata will by on separate physical devices - it simply gives device-mapper and userspace tools more flexibility. Signed-off-by: NeilBrown

md-new-param-to_sync_page_io

2011-01-13T22:14:33+00:00

Add new parameter to 'sync_page_io'. The new parameter allows us to distinguish between metadata and data operations. This becomes important later when we add the ability to use separate devices for data and metadata. Signed-off-by: Jonathan Brassow