tree 3496fb7eca85cd629c19cd23afb5341007e9fa21
parent 8c2e870a625bd336b2e7a65a97c1836acef07322
author Neil Brown <neilb@notabene.brown> 1214605874 +1000
committer Neil Brown <neilb@notabene.brown> 1214605874 +1000

Don't acknowlege that stripe-expand is complete until it really is.

We shouldn't acknowledge that a stripe has been expanded (When
reshaping a raid5 by adding a device) until the moved data has
actually been written out.  However we are currently
acknowledging (by calling md_done_sync) when the POST_XOR
is complete and before the write.

So track in s.locked whether there are pending writes, and don't
call md_done_sync yet if there are.

Note: we all set R5_LOCKED on devices which are are about to
read from.  This probably isn't technically necessary, but is
usually done when writing a block, and justifies the use of
s.locked here.

This bug can lead to a crash if an array is stopped while an reshape
is in progress.

Cc: <stable@kernel.org>
Signed-off-by: Neil Brown <neilb@suse.de>