nfsd: hook nfsd_commit up to the nfsd_file cache

Use cached filps if possible instead of opening a new one every time.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/vfs.c

@@ -1133,7 +1133,7 @@ __be32
 nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
                loff_t offset, unsigned long count)
 {
-	struct file	*file;
+	struct nfsd_file	*nf;
 	loff_t			end = LLONG_MAX;
 	__be32			err = nfserr_inval;
 
@@ -1145,12 +1145,12 @@ nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
 			goto out;
 	}
 
-	err = nfsd_open(rqstp, fhp, S_IFREG,
-			NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &file);
+	err = nfsd_file_acquire(rqstp, fhp,
+			NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &nf);
 	if (err)
 		goto out;
 	if (EX_ISSYNC(fhp->fh_export)) {
-		int err2 = vfs_fsync_range(file, offset, end, 0);
+		int err2 = vfs_fsync_range(nf->nf_file, offset, end, 0);
 
 		if (err2 != -EINVAL)
 			err = nfserrno(err2);
@@ -1158,7 +1158,7 @@ nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
 			err = nfserr_notsupp;
 	}
 
-	fput(file);
+	nfsd_file_put(nf);
 out:
 	return err;
 }