Thanks Bernd for looking into this! I think 6.9 added passthrough support. Are you using that? > Not yet, but we have plans to try this out. FOPEN_CACHE_DIR is default when there is no fuse-server open method defined - does your implementation have an open/dir_open? > Yes, here is the implementation in GCSFuse (internally uses jacobsa/fuse library) - https://github.com/GoogleCloudPlatform/gcsfuse/blob/b0ca9c5b2c0a35aeb8a48fe7a36120d7b33216aa/internal/fs/fs.go#L2328 Here, op.CacheDir maps to FOPEN_CACHE_DIR and op.KeepCache maps to FOPEN_KEEP_CACHE. I think the only user of FOPEN_CACHE_DIR is in fs/fuse/readdir.c and that always checks if it is set - either the flag gets set or does not come into role at all, because passthrough is used? > Being honest, I don't have much idea of linux source code. As a user, to me the FOPEN_CACHE_DIR flag is working as expected. The problem is with the FOPEN_KEEP_CACHE flags, setting this should evict the dir cache, but it's not happening for linux 6.9.x and above. Although I see a line in fs/fuse/dir.c (https://github.com/torvalds/linux/blob/ccb98ccef0e543c2bd4ef1a72270461957f3d8d0/fs/fuse/dir.c#L718) which invalidates the inode pages if FOPEN_KEEP_CACHE is not set. So my ultimate question would be: (1) Do you see such recent changes in fs/fuse which explains the above regression? (2) If the changes are intentional, what should be the right way for fuse-server to evict the dir-cache (other than auto eviction due to change in dir-content, e.g., addition of new file inside a dir)? Thanks, Prince Kumar. On Tue, Dec 31, 2024 at 5:11 AM Bernd Schubert <bernd@xxxxxxxxxxx> wrote: > > > > On 12/30/24 05:41, Prince Kumar wrote: > > Hello Team, > > > > I see a regression in the fuse-filesystem for the linux version 6.9.X > > and onwards, where the FOPEN_KEEP_CACHE flag is not working as > > intended. Just for background, I referred to this linux commit > > (https://github.com/torvalds/linux/commit/6433b8998a21dc597002731c4ceb4144e856edc4) > > to implement directory listing cache in jacobsa/fuse > > (https://github.com/jacobsa/fuse/pull/162). > > > > Ideally, the kernel directory cache should be evicted if the > > user-daemon doesn't set FOPEN_KEEP_CACHE bit as part of the OpenDir > > response, but it's not getting evicted in the linux version 6.9.X and > > onwards. > > > > Could you please help me in resolving this? > > I think 6.9 added passthrough support. Are you using that? Also, > FOPEN_CACHE_DIR is default when there is no fuse-server open method > defined - does your implementation have an open/dir_open? > > I think the only user of FOPEN_CACHE_DIR is in fs/fuse/readdir.c and > that always checks if it is set - either the flag gets set or does not > come into role at all, because passthrough is used? > > > Thanks, > Bernd
