md: MD_CLOSING needs to be cleared after called md_set_readonly or do_md_stop

NeilBrown · shligit · commit 065e519e71b2 · 2017-04-10T10:47:50.000-07:00
if called md_set_readonly and set MD_CLOSING bit, the mddev cannot be opened any more due to the MD_CLOING bit wasn't cleared. Thus it needs to be cleared in md_ioctl after any call to md_set_readonly() or do_md_stop(). Signed-off-by: NeilBrown <neilb@suse.com> Fixes: af8d8e6 ("md: changes for MD_STILL_CLOSED flag") Cc: stable@vger.kernel.org (v4.9+) Signed-off-by: Zhilong Liu <zlliu@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
diff --git a/drivers/md/md.c b/drivers/md/md.c
@@ -6925,6 +6925,7 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
 	void __user *argp = (void __user *)arg;
 	struct mddev *mddev = NULL;
 	int ro;
+	bool did_set_md_closing = false;
 
 	if (!md_ioctl_valid(cmd))
 		return -ENOTTY;
@@ -7014,7 +7015,9 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
 			err = -EBUSY;
 			goto out;
 		}
+		WARN_ON_ONCE(test_bit(MD_CLOSING, &mddev->flags));
 		set_bit(MD_CLOSING, &mddev->flags);
+		did_set_md_closing = true;
 		mutex_unlock(&mddev->open_mutex);
 		sync_blockdev(bdev);
 	}
@@ -7207,6 +7210,8 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
 		mddev->hold_active = 0;
 	mddev_unlock(mddev);
 out:
+	if(did_set_md_closing)
+		clear_bit(MD_CLOSING, &mddev->flags);
 	return err;
 }
 #ifdef CONFIG_COMPAT
