nfsd: clean up supported attribute handling

Minor cleanup, no change in behavior.

Provide helpers for some common attribute bitmap operations.  Drop some
comments that just echo the code.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4proc.c

@@ -96,33 +96,12 @@ check_attr_support(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 {
 	struct dentry *dentry = cstate->current_fh.fh_dentry;
 
-	/*
-	 * Check about attributes are supported by the NFSv4 server or not.
-	 * According to spec, unsupported attributes return ERR_ATTRNOTSUPP.
-	 */
-	if ((bmval[0] & ~nfsd_suppattrs0(cstate->minorversion)) ||
-	    (bmval[1] & ~nfsd_suppattrs1(cstate->minorversion)) ||
-	    (bmval[2] & ~nfsd_suppattrs2(cstate->minorversion)))
+	if (!nfsd_attrs_supported(cstate->minorversion, bmval))
 		return nfserr_attrnotsupp;
-
-	/*
-	 * Check FATTR4_WORD0_ACL can be supported
-	 * in current environment or not.
-	 */
-	if (bmval[0] & FATTR4_WORD0_ACL) {
-		if (!IS_POSIXACL(d_inode(dentry)))
-			return nfserr_attrnotsupp;
-	}
-
-	/*
-	 * According to spec, read-only attributes return ERR_INVAL.
-	 */
-	if (writable) {
-		if ((bmval[0] & ~writable[0]) || (bmval[1] & ~writable[1]) ||
-		    (bmval[2] & ~writable[2]))
-			return nfserr_inval;
-	}
-
+	if ((bmval[0] & FATTR4_WORD0_ACL) && !IS_POSIXACL(d_inode(dentry)))
+		return nfserr_attrnotsupp;
+	if (writable && !bmval_is_subset(bmval, writable))
+		return nfserr_inval;
 	return nfs_ok;
 }
 
@@ -695,9 +674,9 @@ nfsd4_getattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	if (getattr->ga_bmval[1] & NFSD_WRITEONLY_ATTRS_WORD1)
 		return nfserr_inval;
 
-	getattr->ga_bmval[0] &= nfsd_suppattrs0(cstate->minorversion);
-	getattr->ga_bmval[1] &= nfsd_suppattrs1(cstate->minorversion);
-	getattr->ga_bmval[2] &= nfsd_suppattrs2(cstate->minorversion);
+	getattr->ga_bmval[0] &= nfsd_suppattrs[cstate->minorversion][0];
+	getattr->ga_bmval[1] &= nfsd_suppattrs[cstate->minorversion][1];
+	getattr->ga_bmval[2] &= nfsd_suppattrs[cstate->minorversion][2];
 
 	getattr->ga_fhp = &cstate->current_fh;
 	return nfs_ok;
@@ -799,9 +778,9 @@ nfsd4_readdir(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	if (readdir->rd_bmval[1] & NFSD_WRITEONLY_ATTRS_WORD1)
 		return nfserr_inval;
 
-	readdir->rd_bmval[0] &= nfsd_suppattrs0(cstate->minorversion);
-	readdir->rd_bmval[1] &= nfsd_suppattrs1(cstate->minorversion);
-	readdir->rd_bmval[2] &= nfsd_suppattrs2(cstate->minorversion);
+	readdir->rd_bmval[0] &= nfsd_suppattrs[cstate->minorversion][0];
+	readdir->rd_bmval[1] &= nfsd_suppattrs[cstate->minorversion][1];
+	readdir->rd_bmval[2] &= nfsd_suppattrs[cstate->minorversion][2];
 
 	if ((cookie == 1) || (cookie == 2) ||
 	    (cookie == 0 && memcmp(readdir->rd_verf.data, zeroverf.data, NFS4_VERIFIER_SIZE)))

fs/nfsd/nfs4xdr.c

@@ -57,6 +57,20 @@
 
 #define NFSDDBG_FACILITY		NFSDDBG_XDR
 
+u32 nfsd_suppattrs[3][3] = {
+	{NFSD4_SUPPORTED_ATTRS_WORD0,
+	 NFSD4_SUPPORTED_ATTRS_WORD1,
+	 NFSD4_SUPPORTED_ATTRS_WORD2},
+
+	{NFSD4_1_SUPPORTED_ATTRS_WORD0,
+	 NFSD4_1_SUPPORTED_ATTRS_WORD1,
+	 NFSD4_1_SUPPORTED_ATTRS_WORD2},
+
+	{NFSD4_1_SUPPORTED_ATTRS_WORD0,
+	 NFSD4_1_SUPPORTED_ATTRS_WORD1,
+	 NFSD4_2_SUPPORTED_ATTRS_WORD2},
+};
+
 /*
  * As per referral draft, the fsid for a referral MUST be different from the fsid of the containing
  * directory in order to indicate to the client that a filesystem boundary is present
@@ -2340,9 +2354,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
 
 	BUG_ON(bmval1 & NFSD_WRITEONLY_ATTRS_WORD1);
-	BUG_ON(bmval0 & ~nfsd_suppattrs0(minorversion));
-	BUG_ON(bmval1 & ~nfsd_suppattrs1(minorversion));
-	BUG_ON(bmval2 & ~nfsd_suppattrs2(minorversion));
+	BUG_ON(!nfsd_attrs_supported(minorversion, bmval));
 
 	if (exp->ex_fslocs.migrated) {
 		status = fattr_handle_absent_fs(&bmval0, &bmval1, &bmval2, &rdattr_err);
@@ -2409,29 +2421,27 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 	p++;                /* to be backfilled later */
 
 	if (bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) {
-		u32 word0 = nfsd_suppattrs0(minorversion);
-		u32 word1 = nfsd_suppattrs1(minorversion);
-		u32 word2 = nfsd_suppattrs2(minorversion);
+		u32 *supp = nfsd_suppattrs[minorversion];
 
 		if (!IS_POSIXACL(dentry->d_inode))
-			word0 &= ~FATTR4_WORD0_ACL;
+			supp[0] &= ~FATTR4_WORD0_ACL;
 		if (!contextsupport)
-			word2 &= ~FATTR4_WORD2_SECURITY_LABEL;
-		if (!word2) {
+			supp[2] &= ~FATTR4_WORD2_SECURITY_LABEL;
+		if (!supp[2]) {
 			p = xdr_reserve_space(xdr, 12);
 			if (!p)
 				goto out_resource;
 			*p++ = cpu_to_be32(2);
-			*p++ = cpu_to_be32(word0);
-			*p++ = cpu_to_be32(word1);
+			*p++ = cpu_to_be32(supp[0]);
+			*p++ = cpu_to_be32(supp[1]);
 		} else {
 			p = xdr_reserve_space(xdr, 16);
 			if (!p)
 				goto out_resource;
 			*p++ = cpu_to_be32(3);
-			*p++ = cpu_to_be32(word0);
-			*p++ = cpu_to_be32(word1);
-			*p++ = cpu_to_be32(word2);
+			*p++ = cpu_to_be32(supp[0]);
+			*p++ = cpu_to_be32(supp[1]);
+			*p++ = cpu_to_be32(supp[2]);
 		}
 	}
 	if (bmval0 & FATTR4_WORD0_TYPE) {

fs/nfsd/nfsd.h

@@ -361,25 +361,18 @@ void		nfsd_lockd_shutdown(void);
 	(NFSD4_1_SUPPORTED_ATTRS_WORD2 | \
 	NFSD4_2_SECURITY_ATTRS)
 
-static inline u32 nfsd_suppattrs0(u32 minorversion)
-{
-	return minorversion ? NFSD4_1_SUPPORTED_ATTRS_WORD0
-			    : NFSD4_SUPPORTED_ATTRS_WORD0;
-}
+extern u32 nfsd_suppattrs[3][3];
 
-static inline u32 nfsd_suppattrs1(u32 minorversion)
+static inline bool bmval_is_subset(u32 *bm1, u32 *bm2)
 {
-	return minorversion ? NFSD4_1_SUPPORTED_ATTRS_WORD1
-			    : NFSD4_SUPPORTED_ATTRS_WORD1;
+	return !((bm1[0] & ~bm2[0]) ||
+	         (bm1[1] & ~bm2[1]) ||
+		 (bm1[2] & ~bm2[2]));
 }
 
-static inline u32 nfsd_suppattrs2(u32 minorversion)
+static inline bool nfsd_attrs_supported(u32 minorversion, u32 *bmval)
 {
-	switch (minorversion) {
-	default: return NFSD4_2_SUPPORTED_ATTRS_WORD2;
-	case 1:  return NFSD4_1_SUPPORTED_ATTRS_WORD2;
-	case 0:  return NFSD4_SUPPORTED_ATTRS_WORD2;
-	}
+	return bmval_is_subset(bmval, nfsd_suppattrs[minorversion]);
 }
 
 /* These will return ERR_INVAL if specified in GETATTR or READDIR. */