seaweedfs/weed/mount/weedfs_forget.go
2022-02-28 01:23:14 -08:00

70 lines
2.3 KiB
Go

package mount
import (
"context"
"github.com/chrislusf/seaweedfs/weed/util"
)
// Forget is called when the kernel discards entries from its
// dentry cache. This happens on unmount, and when the kernel
// is short on memory. Since it is not guaranteed to occur at
// any moment, and since there is no return value, Forget
// should not do I/O, as there is no channel to report back
// I/O errors.
// from https://github.com/libfuse/libfuse/blob/master/include/fuse_lowlevel.h
/**
* Forget about an inode
*
* This function is called when the kernel removes an inode
* from its internal caches.
*
* The inode's lookup count increases by one for every call to
* fuse_reply_entry and fuse_reply_create. The nlookup parameter
* indicates by how much the lookup count should be decreased.
*
* Inodes with a non-zero lookup count may receive request from
* the kernel even after calls to unlink, rmdir or (when
* overwriting an existing file) rename. Filesystems must handle
* such requests properly and it is recommended to defer removal
* of the inode until the lookup count reaches zero. Calls to
* unlink, rmdir or rename will be followed closely by forget
* unless the file or directory is open, in which case the
* kernel issues forget only after the release or releasedir
* calls.
*
* Note that if a file system will be exported over NFS the
* inodes lifetime must extend even beyond forget. See the
* generation field in struct fuse_entry_param above.
*
* On unmount the lookup count for all inodes implicitly drops
* to zero. It is not guaranteed that the file system will
* receive corresponding forget messages for the affected
* inodes.
*
* Valid replies:
* fuse_reply_none
*
* @param req request handle
* @param ino the inode number
* @param nlookup the number of lookups to forget
*/
/*
https://libfuse.github.io/doxygen/include_2fuse__lowlevel_8h.html
int fuse_reply_entry ( fuse_req_t req,
const struct fuse_entry_param * e
)
Reply with a directory entry
Possible requests: lookup, mknod, mkdir, symlink, link
Side effects: increments the lookup count on success
*/
func (wfs *WFS) Forget(nodeid, nlookup uint64) {
wfs.inodeToPath.Forget(nodeid, nlookup, func(dir util.FullPath) {
wfs.metaCache.DeleteFolderChildren(context.Background(), dir)
})
wfs.fhmap.ReleaseByInode(nodeid)
}