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

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: af8d8e6f0315 ("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
index 1db88d79549a74239068cd5b21241294917c1fc8..a612b9f83069bdb3c0c390ece95828a5698191be 100644 (file)
--- 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 @@ unlock:
                mddev->hold_active = 0;
        mddev_unlock(mddev);
 out:
+       if(did_set_md_closing)
+               clear_bit(MD_CLOSING, &mddev->flags);
        return err;
 }
 #ifdef CONFIG_COMPAT