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@xxxxxxxxx>
---
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;
--
2.19.2
