Add the ability to clean up the dentry cache can be used to clean up resources when VFS umount. #152

zyfjeff · 2023-09-18T08:47:41Z

In order to make the hot upgrade of virtiofs easy, VFS will save pseudo
inodes when umount for easy recovery. However, in the fuse scenario, if
umount does not remove the pseudo inode, it will cause an invalid
directory to be seen on the host, which is not friendly to users. So add
this option to control this behavior.
umount returns the parent's inode information, so that it is convenient
to call fuse's invali entry interface later to clarify the corresponding
dentry cache
Use the invalidate entry provided by the fuse kernel to clear the entry
cache, all code references the libfuse implementation.
Optimize log output and print in vfs umount scenario
1. optimize the log of forget, for scenarios where forget cannot handle when the vfs submount is dropped by umount.
2. remove the error log printed when write fuse fails, and hand it to the caller to process and print.

Signed-off-by: zyfjeff [email protected]

ref: https://github.com/libfuse/libfuse/blob/f44214be6a2abb4c98f61790cae565c06bdb431c/lib/fuse_lowlevel.c#L2332

src/api/vfs/mod.rs

src/api/pseudo_fs.rs

src/lib.rs

src/api/server/sync_io.rs

In order to make the hot upgrade of virtiofs easy, VFS will save pseudo inodes when umount for easy recovery. However, in the fuse scenario, if umount does not remove the pseudo inode, it will cause an invalid directory to be seen on the host, which is not friendly to users. So add this option to control this behavior. Signed-off-by: zyfjeff <[email protected]>

umount returns the parent's inode information, so that it is convenient to call fuse's invali entry interface later to clarify the corresponding dentry cache Signed-off-by: zyfjeff <[email protected]>

Use the invalidate entry provided by the fuse kernel to clear the entry cache, all code references the libfuse implementation. ref: https://github.com/libfuse/libfuse/blob/f44214be6a2abb4c98f61790cae565c06bdb431c/lib/fuse_lowlevel.c#L2332 Signed-off-by: zyfjeff <[email protected]>

1. optimize the log of forget, for scenarios where forget cannot handle when the vfs submount is dropped by umount. 2. remove the error log printed when write fuse fails, and hand it to the caller to process and print. Signed-off-by: zyfjeff <[email protected]>

zyfjeff requested review from bergwolf, imeoer, jiangliu, liubogithub and eryugey as code owners September 18, 2023 08:47

zyfjeff force-pushed the upstream-master branch from 9e0fb0d to 07ba932 Compare September 18, 2023 08:50

eryugey approved these changes Sep 18, 2023

View reviewed changes

zyfjeff force-pushed the upstream-master branch from 07ba932 to 694a8ae Compare September 20, 2023 13:21