nfsd: move most of fh_verify to separate function

Move the code that actually parses the filehandle and looks up the
dentry and export to a separate function.  This simplifies the reference
counting a little and moves fh_verify() a little closer to the kernel
ideal of small, minimally-indentended functions.  Clean up a few other
minor style sins along the way.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Cc: Neil Brown <neilb@suse.de>

fs/nfsd/nfsfh.c

@@ -113,28 +113,19 @@ static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
 }
 
 /*
- * Perform sanity checks on the dentry in a client's file handle.
- *
- * Note that the file handle dentry may need to be freed even after
- * an error return.
- *
- * This is only called at the start of an nfsproc call, so fhp points to
- * a svc_fh which is all 0 except for the over-the-wire file handle.
+ * Use the given filehandle to look up the corresponding export and
+ * dentry.  On success, the results are used to set fh_export and
+ * fh_dentry.
  */
-__be32
-fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
+static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
 {
 	struct knfsd_fh	*fh = &fhp->fh_handle;
-	struct svc_export *exp = NULL;
-	struct dentry	*dentry;
-	__be32		error = 0;
-
-	dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
-
-	if (!fhp->fh_dentry) {
 	struct fid *fid = NULL, sfid;
+	struct svc_export *exp;
+	struct dentry *dentry;
 	int fileid_type;
 	int data_left = fh->fh_size/4;
+	__be32 error;
 
 	error = nfserr_stale;
 	if (rqstp->rq_vers > 2)
@@ -144,13 +135,14 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 
 	if (fh->fh_version == 1) {
 		int len;
-			if (--data_left<0) goto out;
-			switch (fh->fh_auth_type) {
-			case 0: break;
-			default: goto out;
-			}
+
+		if (--data_left < 0)
+			return error;
+		if (fh->fh_auth_type != 0)
+			return error;
 		len = key_len(fh->fh_fsid_type) / 4;
-			if (len == 0) goto out;
+		if (len == 0)
+			return error;
 		if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
 			/* deprecated, convert to type 3 */
 			len = key_len(FSID_ENCODE_DEV)/4;
@@ -158,16 +150,18 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 			fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
 			fh->fh_fsid[1] = fh->fh_fsid[2];
 		}
-			if ((data_left -= len)<0) goto out;
-			exp = rqst_exp_find(rqstp, fh->fh_fsid_type,
-					    fh->fh_auth);
+		data_left -= len;
+		if (data_left < 0)
+			return error;
+		exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_auth);
 		fid = (struct fid *)(fh->fh_auth + len);
 	} else {
 		__u32 tfh[2];
 		dev_t xdev;
 		ino_t xino;
+
 		if (fh->fh_size != NFS_FHSIZE)
-				goto out;
+			return error;
 		/* assume old filehandle format */
 		xdev = old_decode_dev(fh->ofh_xdev);
 		xino = u32_to_ino_t(fh->ofh_xino);
@@ -177,12 +171,10 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 
 	error = nfserr_stale;
 	if (PTR_ERR(exp) == -ENOENT)
-			goto out;
+		return error;
 
-		if (IS_ERR(exp)) {
-			error = nfserrno(PTR_ERR(exp));
-			goto out;
-		}
+	if (IS_ERR(exp))
+		return nfserrno(PTR_ERR(exp));
 
 	error = nfsd_setuser_and_check_port(rqstp, exp);
 	if (error)
@@ -232,7 +224,36 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 	fhp->fh_dentry = dentry;
 	fhp->fh_export = exp;
 	nfsd_nr_verified++;
-		cache_get(&exp->h);
+	return 0;
+out:
+	exp_put(exp);
+	return error;
+}
+
+/*
+ * Perform sanity checks on the dentry in a client's file handle.
+ *
+ * Note that the file handle dentry may need to be freed even after
+ * an error return.
+ *
+ * This is only called at the start of an nfsproc call, so fhp points to
+ * a svc_fh which is all 0 except for the over-the-wire file handle.
+ */
+__be32
+fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
+{
+	struct svc_export *exp;
+	struct dentry	*dentry;
+	__be32		error;
+
+	dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
+
+	if (!fhp->fh_dentry) {
+		error = nfsd_set_fh_dentry(rqstp, fhp);
+		if (error)
+			goto out;
+		dentry = fhp->fh_dentry;
+		exp = fhp->fh_export;
 	} else {
 		/*
 		 * just rechecking permissions
@@ -242,7 +263,6 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 		dprintk("nfsd: fh_verify - just checking\n");
 		dentry = fhp->fh_dentry;
 		exp = fhp->fh_export;
-		cache_get(&exp->h);
 		/*
 		 * Set user creds for this exportpoint; necessary even
 		 * in the "just checking" case because this may be a
@@ -281,8 +301,6 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 			access, ntohl(error));
 	}
 out:
-	if (exp && !IS_ERR(exp))
-		exp_put(exp);
 	if (error == nfserr_stale)
 		nfsdstats.fh_stale++;
 	return error;