linux.git/drivers/md/raid10.c, branch v2.6.30

md/raid10: don't clear bitmap during recovery if array will still be degraded.

2009-05-07T02:48:10+00:00

If we have a raid10 with multiple missing devices, and we recover just
one of these to a spare, then we risk (depending on the bitmap and
array chunk size) clearing bits of the bitmap for which recovery isn't
complete (because a device is still missing).

This can lead to a subsequent "re-add" being recovered without
any IO happening, which would result in loss of data.

This patch takes the safe approach of not clearing bitmap bits
if the array will still be degraded.

This patch is suitable for all active -stable kernels.

Cc: stable@kernel.org
Signed-off-by: NeilBrown

block: move bio list helpers into bio.h

2009-04-15T06:28:09+00:00

It's used by DM and MD and generally useful, so move the bio list
helpers into bio.h.

Signed-off-by: Christoph Hellwig 
Acked-by: Alasdair G Kergon 
Signed-off-by: Jens Axboe

md: 'array_size' sysfs attribute

2009-03-31T04:00:31+00:00

Allow userspace to set the size of the array according to the following
semantics:

1/ size must be <= to the size returned by mddev->pers->size(mddev, 0, 0)
   a) If size is set before the array is running, do_md_run will fail
      if size is greater than the default size
   b) A reshape attempt that reduces the default size to less than the set
      array size should be blocked
2/ once userspace sets the size the kernel will not change it
3/ writing 'default' to this attribute returns control of the size to the
   kernel and reverts to the size reported by the personality

Also, convert locations that need to know the default size from directly
reading ->array_sectors to _size.  Resync/reshape operations
always follow the default size.

Finally, fixup other locations that read a number of 1k-blocks from
userspace to use strict_blocks_to_sectors() which checks for unsigned
long long to sector_t overflow and blocks to sectors overflow.

Reviewed-by: Andre Noll 
Signed-off-by: Dan Williams

md: centralize ->array_sectors modifications

2009-03-31T03:59:03+00:00

Get personalities out of the business of directly modifying
->array_sectors.  Lays groundwork to introduce policy on when
->array_sectors can be modified.

Reviewed-by: Andre Noll 
Signed-off-by: Dan Williams

md: add 'size' as a personality method

2009-03-31T03:57:49+00:00

In preparation for giving userspace control over ->array_sectors we need
to be able to retrieve the 'default' size, and the 'anticipated' size
when a reshape is requested.  For personalities that do not reshape emit
a warning if anything but the default size is requested.

In the raid5 case we need to update ->previous_raid_disks to make the
new 'default' size available.

Reviewed-by: Andre Noll 
Signed-off-by: Dan Williams

md: enable suspend/resume of md devices.

2009-03-31T03:39:39+00:00

To be able to change the 'level' of an md/raid array, we need to
suspend the device so that no requests are active - then move some
pointers around etc.

The code already keeps counts of active requests and the ->quiesce
function can be used to wait until those counts hit zero.
However the quiesce function blocks new requests once they are all
ready 'inside' the personality module, and that is too late if we want
to replace the personality modules.

So make all md requests come in through a common md_make_request
function that keeps track of how many requests have entered the
modules but may not yet be on the internal reference counts.
Allow md_make_request to be blocked when we want to suspend the
device, and make it possible to wait for all those in-transit requests
to be added to internal lists so that ->quiesce can wait for them.

There is still a problem that when a request completes, we drop the
ref count inside the personality code so there is a short time between
when the refcount hits zero, and when the personality code is no
longer being used.
The personality code never blocks (schedule or spinlock) between
dropping the refcount and exiting the routine, so this should be safe
(as put_module calls synchronize_sched() before unmapping the module
code).

Signed-off-by: NeilBrown

md: Make mddev->size sector-based.

2009-03-31T03:33:13+00:00

This patch renames the "size" field of struct mddev_s to "dev_sectors"
and stores the number of 512-byte sectors instead of the number of
1K-blocks in it.

All users of that field, including raid levels 1,4-6,10, are adjusted
accordingly. This simplifies the code a bit because it allows to get
rid of a couple of divisions/multiplications by two.

In order to make checkpatch happy, some minor coding style issues
have also been addressed. In particular, size_store() now uses
strict_strtoull() instead of simple_strtoull().

Signed-off-by: Andre Noll 
Signed-off-by: NeilBrown

md: move md_k.h from include/linux/raid/ to drivers/md/

2009-03-31T03:33:13+00:00

It really is nicer to keep related code together..

Signed-off-by: NeilBrown

md: move lots of #include lines out of .h files and into .c

2009-03-31T03:33:13+00:00

This makes the includes more explicit, and is preparation for moving
md_k.h to drivers/md/md.h

Remove include/raid/md.h as its only remaining use was to #include
other files.

Signed-off-by: NeilBrown

md: move headers out of include/linux/raid/

2009-03-31T03:27:03+00:00

Move the headers with the local structures for the disciplines and
bitmap.h into drivers/md/ so that they are more easily grepable for
hacking and not far away.  md.h is left where it is for now as there
are some uses from the outside.

Signed-off-by: Christoph Hellwig 
Signed-off-by: NeilBrown