md: make sure a reshape is started when device switches to read-write
authorNeilBrown <neilb@suse.de>
Tue, 4 Mar 2008 22:29:32 +0000 (14:29 -0800)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Wed, 5 Mar 2008 00:35:18 +0000 (16:35 -0800)
A resync/reshape/recovery thread will refuse to progress when the array is
marked read-only.  So whenever it mark it not read-only, it is important to
wake up thread resync thread.  There is one place we didn't do this.

The problem manifests if the start_ro module parameters is set, and a raid5
array that is in the middle of a reshape (restripe) is started.  The array
will initially be semi-read-only (meaning it acts like it is readonly until
the first write).  So the reshape will not proceed.

On the first write, the array will become read-write, but the reshape will not
be started, and there is no event which will ever restart that thread.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/md/md.c

index a71241c..a986845 100644 (file)
@@ -5356,6 +5356,7 @@ void md_write_start(mddev_t *mddev, struct bio *bi)
                mddev->ro = 0;
                set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
                md_wakeup_thread(mddev->thread);
+               md_wakeup_thread(mddev->sync_thread);
        }
        atomic_inc(&mddev->writes_pending);
        if (mddev->in_sync) {