From: Li Nan <redacted>

The raid should not be opened anymore when it is about to be stopped.
However, other processes can open it again if the flag MD_CLOSING is
cleared before exiting. From now on, this flag will not be cleared when
the raid will be stopped.

Fixes: 065e519e71b2 ("md: MD_CLOSING needs to be cleared after called
md_set_readonly or do_md_stop") Signed-off-by: Li Nan [off-list ref]
---
 drivers/md/md.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 9bdd57324c37..4bf821b89415 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c

@@ -6254,7 +6254,15 @@ static void md_clean(struct mddev *mddev)
 	mddev->persistent = 0;
 	mddev->level = LEVEL_NONE;
 	mddev->clevel[0] = 0;
-	mddev->flags = 0;
+	/*
+	 * Don't clear MD_CLOSING, or mddev can be opened again.
+	 * 'hold_active != 0' means mddev is still in the creation
+	 * process and will be used later.
+	 */
+	if (mddev->hold_active)
+		mddev->flags = 0;
+	else
+		mddev->flags &= BIT_ULL_MASK(MD_CLOSING);
 	mddev->sb_flags = 0;
 	mddev->ro = MD_RDWR;
 	mddev->metadata_type[0] = 0;

@@ -7728,6 +7736,12 @@ static int md_ioctl(struct block_device *bdev,

blk_mode_t mode, 
 	case STOP_ARRAY:
 		err = do_md_stop(mddev, 0, bdev);
+		if (!err)
+			/*
+			 * mddev has been stopped, keep flag the
+			 * MD_CLOSING to prevent reuse.
+			 */
+			did_set_md_closing = false;