Hi Ilya,
On 11/18/2019 09:38 PM, Ilya Dryomov wrote:
Hello,
This series makes read-only mappings compatible with read-only caps:
we no longer establish a watch,
Although this is true in userspace librbd, I think that's wired: when
there is someone is reading this image, it can be removed. And the
reader will get all zero for later reads.
What about register a watcher but always ack for notifications? Then
we can prevent removing from image being reading.
Ilya, Jason, what's your opinion?
Thanx
acquire header and object map locks,
etc. In addition, because images mapped read-only can no longer be
flipped to read-write, we allow read-only mappings with unsupported
features, as long as the image is still readable.
Thanks,
Ilya
Ilya Dryomov (9):
rbd: introduce rbd_is_snap()
rbd: introduce RBD_DEV_FLAG_READONLY
rbd: treat images mapped read-only seriously
rbd: disallow read-write partitions on images mapped read-only
rbd: don't acquire exclusive lock for read-only mappings
rbd: don't establish watch for read-only mappings
rbd: remove snapshot existence validation code
rbd: don't query snapshot features
rbd: ask for a weaker incompat mask for read-only mappings
drivers/block/rbd.c | 203 ++++++++++++++++++++------------------------
1 file changed, 93 insertions(+), 110 deletions(-)
