dtrace_vfs4
A dtrace provider for virtual file system
Usage
vfs:fplookup:function:name
vfs:namecache:function:name
vfs:namei:function:name
vfs:vop:function:name
Overview
The DTrace vfs provider allows users to trace events in the VFS(9) layer, the kernel interface for file systems on FreeBSD.
Run ‘dtrace -l -P vfs’ to list all vfs probes. Add -v to generate program stability reports, which contain information about the number of probe arguments and their types.
The fplookup module defines a single probe, vfs:fplookup:lookup:done(struct nameidata *ndp, int line, bool status_code), that instruments the fast path lookup code in VFS(9).
The namecache module provides probes related to the VFS(9) cache. Consult the source code in src/sys/kern/vfs_cache.c for more details.
The namei module manages probes related to pathname translation and lookup operations. Refer to namei(9) to learn more.
The vop module contains probes related to the functions responsible for vnode(9) operations.
Compatibility
This provider is specific to FreeBSD.
Examples
Check what lookups failed to be handled in a lockless manner:
# dtrace -n 'vfs:fplookup:lookup:done { @[arg1, arg2] = count(); }'
Releases
4 releases since FreeBSD 14.4-RELEASE; the text changed 1 time.