Grow: report better message when --grow --chunk cannot work.

When changing the chunksize of an array, the new chunksize must
divide the device size.
If it doesn't we report a very brief message.
Make this message a bit longer and suggest a way forward be reducing
the size of the array.

Reported-by: Mark Knecht <markknecht@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Grow: lack of head/tail space not fatal for RAID5 etc.

For RAID10, we must have head/tail space for reshape.
For RAID4/5/6 we can use a spare or a backup file.

So make that distinction.

Signed-off-by: NeilBrown <neilb@suse.de>
Grow: fix crash when restarting an array.

After the 'started' label it is assumed that 'sra' is set, so better
set it when jumping there.

Signed-off-by: NeilBrown <neilb@suse.de>
Assemble: remove some stray tracing.

Was introduced in:
  Assemble: when forcing a single-degraded RAID6 array, trigger a 'repair'.

Signed-off-by: NeilBrown <neilb@suse.de>
"make test" should build "raid6check"

As there are selftests for raid6check.

Signed-off-by: NeilBrown <neilb@suse.de>
tests/raid6repair: default data offset has changed.

So the test scripts must change too.

Signed-off-by: NeilBrown <neilb2suse.de>
revert-reshape: make sure reshape_position is acceptable.

We can only revert a reshape if the reshape_position aligns
properly for the old geometry.
If it doesn't we just fail for now.

Also fix a +/- error with updating raid_disks for super1.c

Signed-off-by: NeilBrown <neilb@suse.de>
New function: sysfs_wait

We have several places that wait for activity on a sysfs
file.  Combine most of these into a single 'sysfs_wait' function.

Signed-off-by: NeilBrown <neilb@suse.de>
Manage: check alignment when stopping an array undergoing reshape.

To be able to revert-reshape of raid4/5/6 which is changing
the number of devices, the reshape must has been stopped on a multiple
of the old and new stripe sizes.

The kernel only enforces the new stripe size multiple.

So we enforce the old-stripe-size multiple by careful use of
"sync_max" and monitoring "reshape_position".

Signed-off-by: NeilBrown <neilb@suse.de>
mdadm.8.in: Fix typo: previous -> previously

Signed-off-by: Wieland Hoffmann <themineo@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Detail: Factor out add_device()

Makes the code a little more readable.

Signed-off-by: Martin Wilck <mwilck@arcor.de>
Signed-off-by: NeilBrown <neilb@suse.de>
Move conf_line and free_line from conf.c to lib.c

As they are uses for mdstat as well as mdadm.conf, they don't really
belong in conf.c

This removes a dependency between mdmon and conf.c

Signed-off-by: NeilBrown <neilb@suse.de>
Move find_free_devnum to mdopen.c

There is only one called to find_free_devnum and it is in mdopen.c

The removes a dependency between util.c and config.c which allows
us to now drop config.o from mdmon.

Signed-off-by: NeilBrown <neilb@suse.de>
Assemble: write raid-disks should be less fatal.

If the container metadata doesn't know how many device to expect (as
is the case with IMSM), don't fail an --assemble which over-specifies
the number of devices.

Signed-off-by: NeilBrown <neilb@suse.de>
Config: use better device names for "DEVICES container"

When "containers" appears on the "DEVICES" line (which is does by
default), use names from the mdadm map file instead of kernel names,
when possible.
This mean that the name will be more likely to appear in mdadm.conf
and so more likely to match "container=" tags.

Signed-off-by: NeilBrown <neilb@suse.de>
Assemble: ignore devices= if container= is present.

If "container=" is present, then we are going to assemble from the
given container where that container is made of those devices or not.
So in this case the "devices=" is purely documentation and is best
ignored.

As part of this, move the test on the "container=" value when that
start with "/" up before the device is opened.  There sooner we test
things, the better.

Reported-by: Martin Wilck <mwilck@arcor.de>
Signed-off-by: NeilBrown <neilb@suse.de>