[PATCH v4 10/18] nfsd: add tracepoint to nfsd_readdir

cel
2025-05-03T19:59:50Z

Observe the start of NFS READDIR operations.

The NFS READDIR's count argument can be interesting when tuning a
client's readdir behavior.

However, the count argument is not passed to nfsd_readdir(). To
properly capture the count argument, this tracepoint must appear in
each proc function before the nfsd_readdir() call.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/nfsd/nfs3proc.c | 2 ++
fs/nfsd/nfs4proc.c | 3 +++
fs/nfsd/nfsproc.c | 2 ++
fs/nfsd/trace.h | 26 ++++++++++++++++++++++++++
4 files changed, 33 insertions(+)

diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index 5d2b081072e8..80096a5c4865 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -625,6 +625,7 @@ nfsd3_proc_readdir(struct svc_rqst *rqstp)
dprintk("nfsd: READDIR(3) %s %d bytes at %d\n",
SVCFH_fmt(&argp->fh),
argp->count, (u32) argp->cookie);
+ trace_nfsd_vfs_readdir(rqstp, &argp->fh, argp->count, argp->cookie);

nfsd3_init_dirlist_pages(rqstp, resp, argp->count);

@@ -659,6 +660,7 @@ nfsd3_proc_readdirplus(struct svc_rqst *rqstp)
dprintk("nfsd: READDIR+(3) %s %d bytes at %d\n",
SVCFH_fmt(&argp->fh),
argp->count, (u32) argp->cookie);
+ trace_nfsd_vfs_readdir(rqstp, &argp->fh, argp->count, argp->cookie);

nfsd3_init_dirlist_pages(rqstp, resp, argp->count);

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 77895e099673..483fd8b26f9d 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -998,6 +998,9 @@ nfsd4_readdir(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
u64 cookie = readdir->rd_cookie;
static const nfs4_verifier zeroverf;

+ trace_nfsd_vfs_readdir(rqstp, &cstate->current_fh,
+ readdir->rd_maxcount, readdir->rd_cookie);
+
/* no need to check permission - this will be done in nfsd_readdir() */

if (readdir->rd_bmval[1] & NFSD_WRITEONLY_ATTRS_WORD1)
diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index 6dda081eb24c..c561af30c37a 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -10,6 +10,7 @@
#include "cache.h"
#include "xdr.h"
#include "vfs.h"
+#include "trace.h"

#define NFSDDBG_FACILITY NFSDDBG_PROC

@@ -618,6 +619,7 @@ nfsd_proc_readdir(struct svc_rqst *rqstp)
dprintk("nfsd: READDIR %s %d bytes at %d\n",
SVCFH_fmt(&argp->fh),
argp->count, argp->cookie);
+ trace_nfsd_vfs_readdir(rqstp, &argp->fh, argp->count, argp->cookie);

nfsd_init_dirlist_pages(rqstp, resp, argp->count);

diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
index 46091d7f2260..bed58cf55c10 100644
--- a/fs/nfsd/trace.h
+++ b/fs/nfsd/trace.h
@@ -2553,6 +2553,32 @@ TRACE_EVENT(nfsd_vfs_rename,
)
);

+TRACE_EVENT(nfsd_vfs_readdir,
+ TP_PROTO(
+ const struct svc_rqst *rqstp,
+ const struct svc_fh *fhp,
+ u32 count,
+ u64 offset
+ ),
+ TP_ARGS(rqstp, fhp, count, offset),
+ TP_STRUCT__entry(
+ NFSD_TRACE_PROC_CALL_FIELDS(rqstp)
+ __field(u32, fh_hash)
+ __field(u32, count)
+ __field(u64, offset)
+ ),
+ TP_fast_assign(
+ NFSD_TRACE_PROC_CALL_ASSIGNMENTS(rqstp);
+ __entry->fh_hash = knfsd_fh_hash(&fhp->fh_handle);
+ __entry->count = count;
+ __entry->offset = offset;
+ ),
+ TP_printk("xid=0x%08x fh_hash=0x%08x offset=%llu count=%u",
+ __entry->xid, __entry->fh_hash,
+ __entry->offset, __entry->count
+ )
+);
+
#endif /* _NFSD_TRACE_H */

#undef TRACE_INCLUDE_PATH
--
2.49.0