On Mon, Aug 21, 2023 at 6:27 PM Amir Goldstein <amir73il@xxxxxxxxx> wrote: > > On Wed, May 24, 2023 at 1:03 PM Amir Goldstein <amir73il@xxxxxxxxx> wrote: > > > > On Mon, May 22, 2023 at 6:20 PM Miklos Szeredi <miklos@xxxxxxxxxx> wrote: > > > > > > On Fri, 19 May 2023 at 14:57, Amir Goldstein <amir73il@xxxxxxxxx> wrote: > > > > > > > > Extend the passthrough feature by handling asynchronous IO both for read > > > > and write operations. > > > > > > > > When an AIO request is received, if the request targets a FUSE file with > > > > the passthrough functionality enabled, a new identical AIO request is > > > > created. The new request targets the backing file and gets assigned > > > > a special FUSE passthrough AIO completion callback. > > > > > > > > When the backing file AIO request is completed, the FUSE > > > > passthrough AIO completion callback is executed and propagates the > > > > completion signal to the FUSE AIO request by triggering its completion > > > > callback as well. > > > > > > Overlayfs added refcounting to the async req (commit 9a2544037600 > > > ("ovl: fix use after free in struct ovl_aio_req")). Is that not > > > needed for fuse as well? > > > > > > Would it make sense to try and merge the two implementations? > > > > > > > Makes sense - I will look into it. > > > Hi Miklos, > > Getting back to this. > Did you mean something like that? (only compile tested) > > https://github.com/amir73il/linux/commits/backing_fs > > If yes, then I wonder: > 1. Is the difference between FUSE_IOCB_MASK and OVL_IOCB_MASK > (i.e. the APPEND flag) intentional? > 2. What would be the right way to do ovl_copyattr() on io completion? > Pass another completion handler to read/write helpers? > This seems a bit ugly. Do you have a nicer idea? > Hmm. Looking closer, ovl_copyattr() in ovl_aio_cleanup_handler() seems a bit racy as it is not done under inode_lock(). I wonder if it is enough to fix that by adding the lock or if we need to resort to a more complicated scheme like FUSE_I_SIZE_UNSTABLE for overlayfs aio? Thanks, Amir.