nfsd: Add I/O trace points in the NFSv4 read proc

NFSv4 read compound processing invokes nfsd_splice_read and
nfs_readv directly, so the trace points currently in nfsd_read are
not invoked for NFSv4 reads.

Move the NFSD READ trace points to common helpers so that NFSv4
reads are captured.

Also, record any local I/O error that occurs, the total count of
bytes that were actually returned, and whether splice or vectored
read was used.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 18 insertions, 16 deletions

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index ee59a0b24fab..2410b093a2e6 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -881,20 +881,24 @@ static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
         return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
 }
 
-static __be32
-nfsd_finish_read(struct file *file, unsigned long *count, int host_err)
+static __be32 nfsd_finish_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
+                               struct file *file, loff_t offset,
+                               unsigned long *count, int host_err)
 {
         if (host_err >= 0) {
                 nfsdstats.io_read += host_err;
                 *count = host_err;
                 fsnotify_access(file);
+                trace_nfsd_read_io_done(rqstp, fhp, offset, *count);
                 return 0;
-        } else 
+        } else {
+                trace_nfsd_read_err(rqstp, fhp, offset, host_err);
                 return nfserrno(host_err);
+        }
 }
 
-__be32 nfsd_splice_read(struct svc_rqst *rqstp,
-                     struct file *file, loff_t offset, unsigned long *count)
+__be32 nfsd_splice_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
+                        struct file *file, loff_t offset, unsigned long *count)
 {
         struct splice_desc sd = {
                 .len            = 0,
@@ -904,21 +908,23 @@ __be32 nfsd_splice_read(struct svc_rqst *rqstp,
         };
         int host_err;
 
+        trace_nfsd_read_splice(rqstp, fhp, offset, *count);
         rqstp->rq_next_page = rqstp->rq_respages + 1;
         host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor);
-        return nfsd_finish_read(file, count, host_err);
+        return nfsd_finish_read(rqstp, fhp, file, offset, count, host_err);
 }
 
-__be32 nfsd_readv(struct file *file, loff_t offset, struct kvec *vec, int vlen,
-                unsigned long *count)
+__be32 nfsd_readv(struct svc_rqst *rqstp, struct svc_fh *fhp,
+                  struct file *file, loff_t offset,
+                  struct kvec *vec, int vlen, unsigned long *count)
 {
         struct iov_iter iter;
         int host_err;
 
+        trace_nfsd_read_vector(rqstp, fhp, offset, *count);
         iov_iter_kvec(&iter, READ | ITER_KVEC, vec, vlen, *count);
         host_err = vfs_iter_read(file, &iter, &offset, 0);
-
-        return nfsd_finish_read(file, count, host_err);
+        return nfsd_finish_read(rqstp, fhp, file, offset, count, host_err);
 }
 
 /*
@@ -1034,14 +1040,10 @@ __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
 
         ra = nfsd_init_raparms(file);
 
-        trace_nfsd_read_opened(rqstp, fhp, offset, *count);
-
         if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags))
-                err = nfsd_splice_read(rqstp, file, offset, count);
+                err = nfsd_splice_read(rqstp, fhp, file, offset, count);
         else
-                err = nfsd_readv(file, offset, vec, vlen, count);
-
-        trace_nfsd_read_io_done(rqstp, fhp, offset, *count);
+                err = nfsd_readv(rqstp, fhp, file, offset, vec, vlen, count);
 
         if (ra)
                 nfsd_put_raparams(file, ra);