litmus-rt.git/include/linux/raid, branch v2.6.20

[PATCH] md: fix potential memalloc deadlock in md

2007-01-26T21:51:00+00:00

If a GFP_KERNEL allocation is attempted in md while the mddev_lock is held,
it is possible for a deadlock to eventuate.

This happens if the array was marked 'clean', and the memalloc triggers a
write-out to the md device.

For the writeout to succeed, the array must be marked 'dirty', and that
requires getting the mddev_lock.

So, before attempting a GFP_KERNEL allocation while holding the lock, make
sure the array is marked 'dirty' (unless it is currently read-only).

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: allow reads that have bypassed the cache to be retried on failure

2006-12-10T17:57:20+00:00

If a bypass-the-cache read fails, we simply try again through the cache.  If
it fails again it will trigger normal recovery precedures.

update 1:

From: NeilBrown 

1/
  chunk_aligned_read and retry_aligned_read assume that
      data_disks == raid_disks - 1
  which is not true for raid6.
  So when an aligned read request bypasses the cache, we can get the wrong data.

2/ The cloned bio is being used-after-free in raid5_align_endio
   (to test BIO_UPTODATE).

3/ We forgot to add rdev->data_offset when submitting
   a bio for aligned-read

4/ clone_bio calls blk_recount_segments and then we change bi_bdev,
   so we need to invalidate the segment counts.

5/ We don't de-reference the rdev when the read completes.
   This means we need to record the rdev to so it is still
   available in the end_io routine.  Fortunately
   bi_next in the original bio is unused at this point so
   we can stuff it in there.

6/ We leak a cloned bio if the target rdev is not usable.

From: NeilBrown 

update 2:

1/ When aligned requests fail (read error) they need to be retried
   via the normal method (stripe cache).  As we cannot be sure that
   we can process a single read in one go (we may not be able to
   allocate all the stripes needed) we store a bio-being-retried
   and a list of bioes-that-still-need-to-be-retried.
   When find a bio that needs to be retried, we should add it to
   the list, not to single-bio...

2/ We were never incrementing 'scnt' when resubmitting failed
   aligned requests.

[akpm@osdl.org: build fix]
Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] slab: remove kmem_cache_t

2006-12-07T16:39:25+00:00

Replace all uses of kmem_cache_t with struct kmem_cache.

The patch was generated using the following script:

	#!/bin/sh
	#
	# Replace one string by another in all the kernel sources.
	#

	set -e

	for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do
		quilt add $file
		sed -e "1,\$s/$1/$2/g" $file >/tmp/$$
		mv /tmp/$$ $file
		quilt refresh
	done

The script was run like this

	sh replace kmem_cache_t "struct kmem_cache"

Signed-off-by: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: endian annotations for the bitmap superblock

2006-10-21T20:35:05+00:00

And a couple of bug fixes found by sparse.

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: endian annotation for v1 superblock access

2006-10-21T20:35:05+00:00

Includes a couple of bugfixes found by sparse.

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: remove MAX_MD_DEVS which is an arbitrary limit

2006-10-03T15:04:18+00:00

Once upon a time we needed to fixed limit to the number of md devices,
probably because we preallocated some array.  This need no longer exists, but
we still have an arbitrary limit.

So remove MAX_MD_DEVS and allow as many devices as we can fit into the 'minor'
part of a device number.

Also remove some useless noise at init time (which reports MAX_MD_DEVS) and
remove MD_THREAD_NAME_MAX which hasn't been used for a while.

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: Remove working_disks from raid1 state data

2006-10-03T15:04:17+00:00

It is equivalent to conf->raid_disks - conf->mddev->degraded.

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: new sysfs interface for setting bits in the write-intent-bitmap

2006-10-03T15:04:17+00:00

Add a new sysfs interface that allows the bitmap of an array to be dirtied.
The interface is write-only, and is used as follows:

echo "1000" > /sys/block/md2/md/bitmap

(dirty the bit for chunk 1000 [offset 0] in the in-memory and on-disk
bitmaps of array md2)

echo "1000-2000" > /sys/block/md1/md/bitmap

(dirty the bits for chunks 1000-2000 in md1's bitmap)

This is useful, for example, in cluster environments where you may need to
combine two disjoint bitmaps into one (following a server failure, after a
secondary server has taken over the array).  By combining the bitmaps on
the two servers, a full resync can be avoided (This was discussed on the
list back on March 18, 2005, "[PATCH 1/2] md bitmap bug fixes" thread).

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: remove 'working_disks' from raid10 state

2006-10-03T15:04:17+00:00

It isn't needed as mddev->degraded contains equivalent info.

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: remove the working_disks and failed_disks from raid5 state data.

2006-10-03T15:04:17+00:00

They are not needed.  conf->failed_disks is the same as mddev->degraded and
conf->working_disks is conf->raid_disks - mddev->degraded.

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds