md/raid5: use seqcount to protect access to shape in make_request.
authorNeilBrown <neilb@suse.de>
Tue, 27 Aug 2013 05:52:13 +0000 (15:52 +1000)
committerNeilBrown <neilb@suse.de>
Wed, 28 Aug 2013 06:58:36 +0000 (16:58 +1000)
commitc46501b2deaa06efcaaf82917281941f02c6b307
treebafe1a096cda8f657074d59cec815b7ae717cd96
parentb721420e8719131896b009b11edbbd27d9b85e98
md/raid5: use seqcount to protect access to shape in make_request.

make_request() access various shape parameters (raid_disks, chunk_size
etc) which might be changed by raid5_start_reshape().

If the later is called at and awkward time during the form, the wrong
stripe_head might be used.

So introduce a 'seqcount' and after finding a stripe_head make sure
there is no reason to expect that we got the wrong one.

Signed-off-by: NeilBrown <neilb@suse.de>
drivers/md/raid5.c
drivers/md/raid5.h