[PATCH v4 04/18] nfsd: add a tracepoint to nfsd_lookup_dentry

cel
2025-05-03T19:59:45Z

Replace the dprintk in nfsd_lookup_dentry() with a trace point.
nfsd_lookup_dentry() is called frequently enough that enabling this
dprintk call site would result in log floods and performance issues.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/nfsd/trace.h | 23 +++++++++++++++++++++++
fs/nfsd/vfs.c | 2 +-
2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
index b435276a1aaa..661a870d62f5 100644
--- a/fs/nfsd/trace.h
+++ b/fs/nfsd/trace.h
@@ -2394,6 +2394,29 @@ TRACE_EVENT(nfsd_vfs_setattr,
)
)

+TRACE_EVENT(nfsd_vfs_lookup,
+ TP_PROTO(
+ const struct svc_rqst *rqstp,
+ const struct svc_fh *fhp,
+ const char *name,
+ unsigned int len
+ ),
+ TP_ARGS(rqstp, fhp, name, len),
+ TP_STRUCT__entry(
+ NFSD_TRACE_PROC_CALL_FIELDS(rqstp)
+ __field(u32, fh_hash)
+ __string_len(name, name, len)
+ ),
+ TP_fast_assign(
+ NFSD_TRACE_PROC_CALL_ASSIGNMENTS(rqstp);
+ __entry->fh_hash = knfsd_fh_hash(&fhp->fh_handle);
+ __assign_str(name);
+ ),
+ TP_printk("xid=0x%08x fh_hash=0x%08x name=%s",
+ __entry->xid, __entry->fh_hash, __get_str(name)
+ )
+);
+
#endif /* _NFSD_TRACE_H */

#undef TRACE_INCLUDE_PATH
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 9e0a858d2129..657ba0c2da14 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -246,7 +246,7 @@ nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct dentry *dentry;
int host_err;

- dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);
+ trace_nfsd_vfs_lookup(rqstp, fhp, name, len);

dparent = fhp->fh_dentry;
exp = exp_get(fhp->fh_export);
--
2.49.0