md: remove check for MD_RECOVERY_NEEDED in action_store.
md currently doesn't allow a 'sync_action' such as 'reshape' to be set
while MD_RECOVERY_NEEDED is set.
This s a problem, particularly since commit 738a273806ee as that can
cause ->check_shape to call mddev_resume() which sets
MD_RECOVERY_NEEDED. So by the time we come to start 'reshape' it is
very likely that MD_RECOVERY_NEEDED is still set.
Testing for this flag is not really needed and is in any case very
racy as it can be set at any moment - asynchronously. Any race
between setting a sync_action and setting MD_RECOVERY_NEEDED must
already be handled properly in some locked code, probably
md_check_recovery(), so remove the test here.
The test on MD_RECOVERY_RUNNING is also racy in the 'reshape' case
so we should test it again after getting mddev_lock().
As this fixes a race and a regression which can cause 'reshape' to
fail, it is suitable for -stable kernels since 4.1
Reported-by: Xiao Ni <xni@redhat.com>
Fixes: 738a273806ee ("md/raid5: fix allocation of 'scribble' array.")
Cc: stable@vger.kernel.org (v4.1+)
Signed-off-by: NeilBrown <neilb@suse.com>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index dbedc58..61aacab 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4326,8 +4326,7 @@
}
mddev_unlock(mddev);
}
- } else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
- test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
+ } else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
return -EBUSY;
else if (cmd_match(page, "resync"))
clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
@@ -4340,8 +4339,12 @@
return -EINVAL;
err = mddev_lock(mddev);
if (!err) {
- clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
- err = mddev->pers->start_reshape(mddev);
+ if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
+ err = -EBUSY;
+ else {
+ clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+ err = mddev->pers->start_reshape(mddev);
+ }
mddev_unlock(mddev);
}
if (err)