NFSD: Update the GETATTR3res encoder to use struct xdr_stream

As an additional clean up, some renaming is done to more closely
reflect the data type and variable names used in the NFSv3 XDR
definition provided in RFC 1813. "attrstat" is an NFSv2 thingie.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfs3proc.c

@@ -736,7 +736,7 @@ static const struct svc_procedure nfsd_procedures3[22] = {
 	[NFS3PROC_GETATTR] = {
 		.pc_func = nfsd3_proc_getattr,
 		.pc_decode = nfs3svc_decode_fhandleargs,
-		.pc_encode = nfs3svc_encode_attrstatres,
+		.pc_encode = nfs3svc_encode_getattrres,
 		.pc_release = nfs3svc_release_fhandle,
 		.pc_argsize = sizeof(struct nfsd_fhandle),
 		.pc_ressize = sizeof(struct nfsd3_attrstatres),

fs/nfsd/nfs3xdr.c

@@ -20,7 +20,7 @@
 /*
  * Mapping of S_IF* types to NFS file types
  */
-static u32	nfs3_ftypes[] = {
+static const u32 nfs3_ftypes[] = {
 	NF3NON,  NF3FIFO, NF3CHR, NF3BAD,
 	NF3DIR,  NF3BAD,  NF3BLK, NF3BAD,
 	NF3REG,  NF3BAD,  NF3LNK, NF3BAD,
@@ -39,6 +39,15 @@ encode_time3(__be32 *p, struct timespec64 *time)
 	return p;
 }
 
+static __be32 *
+encode_nfstime3(__be32 *p, const struct timespec64 *time)
+{
+	*p++ = cpu_to_be32((u32)time->tv_sec);
+	*p++ = cpu_to_be32(time->tv_nsec);
+
+	return p;
+}
+
 static bool
 svcxdr_decode_nfstime3(struct xdr_stream *xdr, struct timespec64 *timep)
 {
@@ -82,6 +91,19 @@ svcxdr_decode_nfs_fh3(struct xdr_stream *xdr, struct svc_fh *fhp)
 	return true;
 }
 
+static bool
+svcxdr_encode_nfsstat3(struct xdr_stream *xdr, __be32 status)
+{
+	__be32 *p;
+
+	p = xdr_reserve_space(xdr, sizeof(status));
+	if (!p)
+		return false;
+	*p = status;
+
+	return true;
+}
+
 static __be32 *
 encode_fh(__be32 *p, struct svc_fh *fhp)
 {
@@ -253,6 +275,58 @@ svcxdr_decode_devicedata3(struct svc_rqst *rqstp, struct xdr_stream *xdr,
 		svcxdr_decode_specdata3(xdr, args);
 }
 
+static bool
+svcxdr_encode_fattr3(struct svc_rqst *rqstp, struct xdr_stream *xdr,
+		     const struct svc_fh *fhp, const struct kstat *stat)
+{
+	struct user_namespace *userns = nfsd_user_namespace(rqstp);
+	__be32 *p;
+	u64 fsid;
+
+	p = xdr_reserve_space(xdr, XDR_UNIT * 21);
+	if (!p)
+		return false;
+
+	*p++ = cpu_to_be32(nfs3_ftypes[(stat->mode & S_IFMT) >> 12]);
+	*p++ = cpu_to_be32((u32)(stat->mode & S_IALLUGO));
+	*p++ = cpu_to_be32((u32)stat->nlink);
+	*p++ = cpu_to_be32((u32)from_kuid_munged(userns, stat->uid));
+	*p++ = cpu_to_be32((u32)from_kgid_munged(userns, stat->gid));
+	if (S_ISLNK(stat->mode) && stat->size > NFS3_MAXPATHLEN)
+		p = xdr_encode_hyper(p, (u64)NFS3_MAXPATHLEN);
+	else
+		p = xdr_encode_hyper(p, (u64)stat->size);
+
+	/* used */
+	p = xdr_encode_hyper(p, ((u64)stat->blocks) << 9);
+
+	/* rdev */
+	*p++ = cpu_to_be32((u32)MAJOR(stat->rdev));
+	*p++ = cpu_to_be32((u32)MINOR(stat->rdev));
+
+	switch(fsid_source(fhp)) {
+	case FSIDSOURCE_FSID:
+		fsid = (u64)fhp->fh_export->ex_fsid;
+		break;
+	case FSIDSOURCE_UUID:
+		fsid = ((u64 *)fhp->fh_export->ex_uuid)[0];
+		fsid ^= ((u64 *)fhp->fh_export->ex_uuid)[1];
+		break;
+	default:
+		fsid = (u64)huge_encode_dev(fhp->fh_dentry->d_sb->s_dev);
+	}
+	p = xdr_encode_hyper(p, fsid);
+
+	/* fileid */
+	p = xdr_encode_hyper(p, stat->ino);
+
+	p = encode_nfstime3(p, &stat->atime);
+	p = encode_nfstime3(p, &stat->mtime);
+	encode_nfstime3(p, &stat->ctime);
+
+	return true;
+}
+
 static __be32 *encode_fsid(__be32 *p, struct svc_fh *fhp)
 {
 	u64 f;
@@ -713,17 +787,22 @@ nfs3svc_decode_commitargs(struct svc_rqst *rqstp, __be32 *p)
 
 /* GETATTR */
 int
-nfs3svc_encode_attrstat(struct svc_rqst *rqstp, __be32 *p)
+nfs3svc_encode_getattrres(struct svc_rqst *rqstp, __be32 *p)
 {
+	struct xdr_stream *xdr = &rqstp->rq_res_stream;
 	struct nfsd3_attrstat *resp = rqstp->rq_resp;
 
-	*p++ = resp->status;
-	if (resp->status == 0) {
-		lease_get_mtime(d_inode(resp->fh.fh_dentry),
-				&resp->stat.mtime);
-		p = encode_fattr3(rqstp, p, &resp->fh, &resp->stat);
+	if (!svcxdr_encode_nfsstat3(xdr, resp->status))
+		return 0;
+	switch (resp->status) {
+	case nfs_ok:
+		lease_get_mtime(d_inode(resp->fh.fh_dentry), &resp->stat.mtime);
+		if (!svcxdr_encode_fattr3(rqstp, xdr, &resp->fh, &resp->stat))
+			return 0;
+		break;
 	}
-	return xdr_ressize_check(rqstp, p);
+
+	return 1;
 }
 
 /* SETATTR, REMOVE, RMDIR */

fs/nfsd/nfsfh.c

@@ -711,7 +711,7 @@ char * SVCFH_fmt(struct svc_fh *fhp)
 	return buf;
 }
 
-enum fsid_source fsid_source(struct svc_fh *fhp)
+enum fsid_source fsid_source(const struct svc_fh *fhp)
 {
 	if (fhp->fh_handle.fh_version != 1)
 		return FSIDSOURCE_DEV;

fs/nfsd/nfsfh.h

@@ -82,7 +82,7 @@ enum fsid_source {
 	FSIDSOURCE_FSID,
 	FSIDSOURCE_UUID,
 };
-extern enum fsid_source fsid_source(struct svc_fh *fhp);
+extern enum fsid_source fsid_source(const struct svc_fh *fhp);
 
 
 /*

fs/nfsd/xdr3.h

@@ -280,7 +280,7 @@ int nfs3svc_decode_symlinkargs(struct svc_rqst *, __be32 *);
 int nfs3svc_decode_readdirargs(struct svc_rqst *, __be32 *);
 int nfs3svc_decode_readdirplusargs(struct svc_rqst *, __be32 *);
 int nfs3svc_decode_commitargs(struct svc_rqst *, __be32 *);
-int nfs3svc_encode_attrstat(struct svc_rqst *, __be32 *);
+int nfs3svc_encode_getattrres(struct svc_rqst *, __be32 *);
 int nfs3svc_encode_wccstat(struct svc_rqst *, __be32 *);
 int nfs3svc_encode_diropres(struct svc_rqst *, __be32 *);
 int nfs3svc_encode_accessres(struct svc_rqst *, __be32 *);