On 11/6/23 9:08 AM, Bernd Schubert wrote:
Hi Miklos,
On 9/20/23 10:15, Miklos Szeredi wrote:
On Wed, 20 Sept 2023 at 04:41, Tyler Fanelli <tfanelli@xxxxxxxxxx>
wrote:
At the moment, FUSE_INIT's DIRECT_IO_RELAX flag only serves the purpose
of allowing shared mmap of files opened/created with DIRECT_IO enabled.
However, it leaves open the possibility of further relaxing the
DIRECT_IO restrictions (and in-effect, the cache coherency
guarantees of
DIRECT_IO) in the future.
The DIRECT_IO_ALLOW_MMAP flag leaves no ambiguity of its purpose. It
only serves to allow shared mmap of DIRECT_IO files, while still
bypassing the cache on regular reads and writes. The shared mmap is the
only loosening of the cache policy that can take place with the flag.
This removes some ambiguity and introduces a more stable flag to be
used
in FUSE_INIT. Furthermore, we can document that to allow shared
mmap'ing
of DIRECT_IO files, a user must enable DIRECT_IO_ALLOW_MMAP.
Tyler Fanelli (2):
fs/fuse: Rename DIRECT_IO_RELAX to DIRECT_IO_ALLOW_MMAP
docs/fuse-io: Document the usage of DIRECT_IO_ALLOW_MMAP
Looks good.
Applied, thanks. Will send the PR during this merge window, since the
rename could break stuff if already released.
I'm just porting back this feature to our internal fuse module and it
looks these rename patches have been forgotten?
Thanks,
Bernd
From a conversation with Miklos, I believe the patches will be modified
to make DIRECT_IO_RELAX an obsolete alias and still add
DIRECT_IO_ALLOW_MMAP.
Tyler
