Commit c1b62057 authored Nov 12, 2019 by Ilya Dryomov

rbd: disallow read-write partitions on images mapped read-only



If an image is mapped read-only, don't allow setting its partition(s)
to read-write via BLKROSET: with the previous patch all writes to such
images are failed anyway.

If an image is mapped read-write, its partition(s) can be set to
read-only (and back to read-write) as before.  Note that at the rbd
level the image will remain writeable: anything sent down by the block
layer will be executed, including any write from internal kernel users.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>
Reviewed-by: Dongsheng Yang <dongsheng.yang@easystack.cn>

parent b948ad78

drivers/block/rbd.c

+10 −3

Original line number	Diff line number	Diff line
		@@ -706,10 +706,17 @@ static int rbd_ioctl_set_ro(struct rbd_device *rbd_dev, unsigned long arg)
		if (get_user(ro, (int __user *)arg))
		return -EFAULT;

		/* Snapshots can't be marked read-write */
		if (rbd_is_snap(rbd_dev) && !ro)
		/*
		* Both images mapped read-only and snapshots can't be marked
		* read-write.
		*/
		if (!ro) {
		if (rbd_is_ro(rbd_dev))
		return -EROFS;

		rbd_assert(!rbd_is_snap(rbd_dev));
		}

		/* Let blkdev_roset() handle it */
		return -ENOTTY;
		}

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