linux.git/drivers/md, branch v2.6.22-rc4

md: fix bug with linear hot-add and elsewhere

2007-05-24T03:14:14+00:00

Adding a drive to a linear array seems to have stopped working, due to changes
elsewhere in md, and insufficient ongoing testing...

So the patch to make linear hot-add work in the first place introduced a
subtle bug elsewhere that interracts poorly with older version of mdadm.

This fixes it all up.

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

md: don't write more than is required of the last page of a bitmap

2007-05-24T03:14:14+00:00

It is possible that real data or metadata follows the bitmap without full page
alignment.

So limit the last write to be only the required number of bytes, rounded up to
the hard sector size of the device.

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

md: avoid overflow in raid0 calculation with large components

2007-05-24T03:14:14+00:00

If a raid0 has a component device larger than 4TB, and is accessed on a 32bit
machines, then as 'chunk' is unsigned long,

   chunk << chunksize_bits

can overflow (this can be as high as the size of the device in KB).  chunk
itself will not overflow (without triggering a BUG).

So change 'chunk' to be 'sector_t, and get rid of the 'BUG' as it becomes
impossible to hit.

Cc: "Jeff Zheng" 
Signed-off-by: Neil Brown 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

md: improve the is_mddev_idle test

2007-05-11T15:29:37+00:00

During a 'resync' or similar activity, md checks if the devices in the
array are otherwise active and winds back resync activity when they are.
This test in done in is_mddev_idle, and it is somewhat fragile - it
sometimes thinks there is non-sync io when there isn't.

The test compares the total sectors of io (disk_stat_read) with the sectors
of resync io (disk->sync_io).  This has problems because total sectors gets
updated when a request completes, while resync io gets updated when the
request is submitted.  The time difference can cause large differenced
between the two which do not actually imply non-resync activity.  The test
currently allows for some fuzz (+/- 4096) but there are some cases when it
is not enough.

The test currently looks for any (non-fuzz) difference, either positive or
negative.  This clearly is not needed.  Any non-sync activity will cause
the total sectors to grow faster than the sync_io count (never slower) so
we only need to look for a positive differences.

If we do this then the amount of in-flight sync io will never cause the
appearance of non-sync IO.  Once enough non-sync IO to worry about starts
happening, resync will be slowed down and the measurements will thus be
more precise (as there is less in-flight) and control of resync will still
be suitably responsive.

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

md: avoid a possibility that a read error can wrongly propagate through md/raid1 to a filesystem.

2007-05-10T16:26:53+00:00

When a raid1 has only one working drive, we want read error to propagate up
to the filesystem as there is no point failing the last drive in an array.

Currently the code perform this check is racy.  If a write and a read a
both submitted to a device on a 2-drive raid1, and the write fails followed
by the read failing, the read will see that there is only one working drive
and will pass the failure up, even though the one working drive is actually
the *other* one.

So, tighten up the locking.

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

Revert "md: improve partition detection in md array"

2007-05-10T01:51:36+00:00

This reverts commit 5b479c91da90eef605f851508744bfe8269591a0.

Quoth Neil Brown:

  "It causes an oops when auto-detecting raid arrays, and it doesn't
   seem easy to fix.

   The array may not be 'open' when do_md_run is called, so
   bdev->bd_disk might be NULL, so bd_set_size can oops.

   This whole approach of opening an md device before it has been
   assembled just seems to get more and more painful.  I think I'm going
   to have to come up with something clever to provide both backward
   comparability with usage expectation, and sane integration into the
   rest of the kernel."

Signed-off-by: Linus Torvalds

md: improve partition detection in md array

2007-05-09T19:30:57+00:00

md currently uses ->media_changed to make sure rescan_partitions
is call on md array after they are assembled.

However that doesn't happen until the array is opened, which is later
than some people would like.

So use blkdev_ioctl to do the rescan immediately that the
array has been assembled.

This means we can remove all the ->change infrastructure as it was only used
to trigger a partition rescan.

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

md: allow reshape_position for md arrays to be set via sysfs

2007-05-09T19:30:57+00:00

"reshape_position" records how much progress has been made on a "reshape"
(adding drives, changing layout or chunksize).

When it is set, the number of drives, layout and chunksize can have
two possible values, an old an a new.

So allow these different values to be visible, and allow both old and new to
be set: Set the old ones first, then the reshape_position, then the new
values.

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

md: remove the slash from the name of a kmem_cache used by raid5

2007-05-09T19:30:57+00:00

SLUB doesn't like slashes as it wants to use the cache name as the name of a
directory (or symlink) in sysfs.

Signed-off-by: Neil Brown 
Acked-by: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

md: stop using csum_partial for checksum calculation in md

2007-05-09T19:30:57+00:00

If CONFIG_NET is not selected, csum_partial is not exported, so md.ko cannot
use it.  We shouldn't really be using csum_partial anyway as it is an
internal-to-networking interface.

So replace it with C code to do the same thing.  Speed is not crucial here, so
something simple and correct is best.

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