Hi Christoph and Martin,
On 23/06/07 12:12AM, Christoph Hellwig wrote:
On Tue, Jun 06, 2023 at 05:05:35PM +0530, Nitesh Shetty wrote:
Downside will be duplicating checks which are present for read, write in
block layer, device-mapper and zoned devices.
But we can do this, shouldn't be an issue.
Yes. Please never overload operations, this is just causing problems
everywhere, and that why I split the operations from the flag a few
years ago.
Sure, we will add REQ_COPY_IN/OUT and send a new version.
The idea behind subsys is to prevent copy across different subsystem.
For example, copy across nvme subsystem and the scsi subsystem. [1]
At present, we don't support inter-namespace(copy across NVMe namespace),
but after community feedback for previous series we left scope for it.
Never leave scope for something that isn't actually added. That just
creates a giant maintainance nightmare. Cross-device copies are giant
nightmare in general, and in the case of NVMe completely unusable
as currently done in the working group. Messing up something that
is entirely reasonable (local copy) for something like that is a sure
way to never get this series in.
Sure, we can do away with subsys and realign more on single namespace copy.
We are planning to use token to store source info, such as src sector,
len and namespace. Something like below,
struct nvme_copy_token {
struct nvme_ns *ns; // to make sure we are copying within same namespace
/* store source info during *IN operation, will be used by *OUT operation */
sector_t src_sector;
sector_t sectors;
};
Do you have any better way to handle this in mind ?
Thank you,
Nitesh Shetty
