[4/9] rbd: disallow read-write partitions on images mapped read-only
diff mbox series

Message ID 20191118133816.3963-5-idryomov@gmail.com
State New
Headers show
Series
  • wip-krbd-readonly
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Commit Message

Ilya Dryomov Nov. 18, 2019, 1:38 p.m. UTC
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>
---
 drivers/block/rbd.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

Comments

Dongsheng Yang Nov. 19, 2019, 8:37 a.m. UTC | #1
On 11/18/2019 09:38 PM, Ilya Dryomov wrote:
> 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: Dongsheng Yang <dongsheng.yang@easystack.cn>
> ---
>   drivers/block/rbd.c | 13 ++++++++++---
>   1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index 842b92ef2c06..979203cd934c 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -706,9 +706,16 @@ 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)
> -		return -EROFS;
> +	/*
> +	 * 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;

Patch
diff mbox series

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 842b92ef2c06..979203cd934c 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -706,9 +706,16 @@  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)
-		return -EROFS;
+	/*
+	 * 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;