linux.git/drivers/md/md.c, branch v2.6.23

[BLOCK] Get rid of request_queue_t typedef

2007-07-24T07:28:11+00:00

Some of the code has been gradually transitioned to using the proper
struct request_queue, but there's lots left. So do a full sweet of
the kernel and get rid of this typedef and replace its uses with
the proper type.

Signed-off-by: Jens Axboe

md: change bitmap_unplug and others to void functions

2007-07-17T17:23:15+00:00

bitmap_unplug only ever returns 0, so it may as well be void.  Two callers try
to print a message if it returns non-zero, but that message is already printed
by bitmap_file_kick.

write_page returns an error which is not consistently checked.  It always
causes BITMAP_WRITE_ERROR to be set on an error, and that can more
conveniently be checked.

When the return of write_page is checked, an error causes bitmap_file_kick to
be called - so move that call into write_page - and protect against recursive
calls into bitmap_file_kick.

bitmap_update_sb returns an error that is never checked.

So make these 'void' and be consistent about checking the bit.

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

md: check that internal bitmap does not overlap other data

2007-07-17T17:23:15+00:00

We current completely trust user-space to set up metadata describing an
consistant array.  In particlar, that the metadata, data, and bitmap do not
overlap.

But userspace can be buggy, and it is better to report an error than corrupt
data.  So put in some appropriate checks.

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

md: improve the is_mddev_idle test fix

2007-07-17T17:23:15+00:00

Don't use 'unsigned' variable to track sync vs non-sync IO, as the only thing
we want to do with them is a signed comparison, and fix up the comment which
had become quite wrong.

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

md: improve message about invalid superblock during autodetect

2007-07-17T17:23:15+00:00

People try to use raid auto-detect with version-1 superblocks (which is not
supported) and get confused when they are told they have an invalid
superblock.

So be more explicit, and say it it is not a valid v0.90 superblock.

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

Freezer: make kernel threads nonfreezable by default

2007-07-17T17:23:02+00:00

Currently, the freezer treats all tasks as freezable, except for the kernel
threads that explicitly set the PF_NOFREEZE flag for themselves.  This
approach is problematic, since it requires every kernel thread to either
set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't
care for the freezing of tasks at all.

It seems better to only require the kernel threads that want to or need to
be frozen to use some freezer-related code and to remove any
freezer-related code from the other (nonfreezable) kernel threads, which is
done in this patch.

The patch causes all kernel threads to be nonfreezable by default (ie.  to
have PF_NOFREEZE set by default) and introduces the set_freezable()
function that should be called by the freezable kernel threads in order to
unset PF_NOFREEZE.  It also makes all of the currently freezable kernel
threads call set_freezable(), so it shouldn't cause any (intentional)
change of behaviour to appear.  Additionally, it updates documentation to
describe the freezing of tasks more accurately.

[akpm@linux-foundation.org: build fixes]
Signed-off-by: Rafael J. Wysocki 
Acked-by: Nigel Cunningham 
Cc: Pavel Machek 
Cc: Oleg Nesterov 
Cc: Gautham R Shenoy 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

xor: make 'xor_blocks' a library routine for use with async_tx

2007-07-13T15:06:14+00:00

The async_tx api tries to use a dma engine for an operation, but will fall
back to an optimized software routine otherwise.  Xor support is
implemented using the raid5 xor routines.  For organizational purposes this
routine is moved to a common area.

The following fixes are also made:
* rename xor_block => xor_blocks, suggested by Adrian Bunk
* ensure that xor.o initializes before md.o in the built-in case
* checkpatch.pl fixes
* mark calibrate_xor_blocks __init, Adrian Bunk

Cc: Adrian Bunk 
Cc: NeilBrown 
Cc: Herbert Xu 
Signed-off-by: Dan Williams

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: 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

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