md: set mddev readonly flag on blkdev BLKROSET ioctl (e2218350) · Commits · 戴 / test

When the user sets the block device to readwrite then the mddev should follow suit. Otherwise, the BUG_ON in md_write_start() will be set to trigger. The reverse direction, setting mddev->ro to match a set readonly request, can be ignored because the blkdev level readonly flag precludes the need to have mddev->ro set correctly. Nevermind the fact that setting mddev->ro to 1 may fail if the array is in use. Cc: <stable@kernel.org> Signed-off-by:

Dan Williams <dan.j.williams@intel.com> Signed-off-by:

NeilBrown <neilb@suse.de>

drivers/md/md.c

+29 −0

Original line number	Diff line number	Diff line
		@@ -5489,6 +5489,7 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
		int err = 0;
		void __user argp = (void __user )arg;
		mddev_t *mddev = NULL;
		int ro;

		if (!capable(CAP_SYS_ADMIN))
		return -EACCES;
		@@ -5624,6 +5625,34 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
		err = do_md_stop(mddev, 1, 1);
		goto done_unlock;

		case BLKROSET:
		if (get_user(ro, (int __user *)(arg))) {
		err = -EFAULT;
		goto done_unlock;
		}
		err = -EINVAL;

		/* if the bdev is going readonly the value of mddev->ro
		* does not matter, no writes are coming
		*/
		if (ro)
		goto done_unlock;

		/* are we are already prepared for writes? */
		if (mddev->ro != 1)
		goto done_unlock;

		/* transitioning to readauto need only happen for
		* arrays that call md_write_start
		*/
		if (mddev->pers) {
		err = restart_array(mddev);
		if (err == 0) {
		mddev->ro = 2;
		set_disk_ro(mddev->gendisk, 0);
		}
		}
		goto done_unlock;
		}

		/*

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