From: NeilBrown <neilb@suse.de>
Date: Tue, 1 Jun 2010 09:37:26 +0000 (+1000)
Subject: md: be more careful setting MD_CHANGE_CLEAN
X-Git-Tag: v2.6.36-rc1~280^2~19
X-Git-Url: http://bbs.cooldavid.org/git/?a=commitdiff_plain;h=676e42d896ab6967859fabbb06f4e11b9615cbcf;p=net-next-2.6.git

md: be more careful setting MD_CHANGE_CLEAN

When MD_CHANGE_CLEAN is set we might block in md_write_start.
So we should only set it when fairly sure that something will clear
it.

There are two places where it is set so as to encourage a metadata
update to record the progress of resync/recovery.  This should only
be done if the internal metadata update mechanisms are in use, which
can be tested by by inspecting '->persistent'.

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

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 1742435ce3a..4518994712c 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -1526,7 +1526,8 @@ void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
 		   atomic_read(&bitmap->mddev->recovery_active) == 0);
 
 	bitmap->mddev->curr_resync_completed = bitmap->mddev->curr_resync;
-	set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
+	if (bitmap->mddev->persistent)
+		set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
 	sector &= ~((1ULL << CHUNK_BLOCK_SHIFT(bitmap)) - 1);
 	s = 0;
 	while (s < sector && s < bitmap->mddev->resync_max_sectors) {
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 9007651ce17..d636b0a40fa 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -6753,7 +6753,8 @@ void md_do_sync(mddev_t *mddev)
 				   atomic_read(&mddev->recovery_active) == 0);
 			mddev->curr_resync_completed =
 				mddev->curr_resync;
-			set_bit(MD_CHANGE_CLEAN, &mddev->flags);
+			if (mddev->persistent)
+				set_bit(MD_CHANGE_CLEAN, &mddev->flags);
 			sysfs_notify(&mddev->kobj, NULL, "sync_completed");
 		}