--update: add 'bbl' and 'no-bbl' to the list of known updates.

so "mdadm -A --update=?" mentions them.

Reported-by: Peter Hoeg <peter@hoeg.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Grow: Report when grow needs metadata update

Report when the array's metadata needs updating instead of just
reporting the generic "kernel too old" message.

Signed-off-by: Andy Smith <andy@strugglers.net>
Signed-off-by: NeilBrown <neilb@suse.de>
mdmon: already read sysfs files once after opening.

seq_file in the kernel will allocate a read buffer on
first read.  We want this to happen under the managemon thread,
not the 'monitor' thread, as the latter is not allow to allocate
memory (might deadlock).
So do a first read after opening.

Signed-off-by: NeilBrown <neilb@suse.de>
Grow: fix resize of array component size to > 32bits

If the request --size to --grow an array to is larger
than 32bits, then mdadm may make the wrong choice and
use ioctl instead of setting component_size via sysfs
and the change is ignored.

Instead of using casts to check for a 32-bit overflow,
just check for set bits outside of INT32_MAX.

Fixes: 4e9a3dd16d656b269f5602624ac4f7109a571368
Signed-off-by: NeilBrown <neilb@suse.de>