NFS: Don't compare apples to elephants to determine access bits

The NFS_ACCESS_* flags aren't a 1:1 mapping to the MAY_* flags, so
checking for MAY_WHATEVER might have surprising results in
nfs*_proc_access().  Let's simplify this check when determining which
bits to ask for, and do it in a generic place instead of copying code
for each NFS version.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/dir.c

@@ -2425,9 +2425,14 @@ static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask)
 	if (!may_block)
 		goto out;
 
-	/* Be clever: ask server to check for all possible rights */
-	cache.mask = NFS_MAY_LOOKUP | NFS_MAY_EXECUTE
-		     | NFS_MAY_WRITE | NFS_MAY_READ;
+	/*
+	 * Determine which access bits we want to ask for...
+	 */
+	cache.mask = NFS_ACCESS_READ | NFS_ACCESS_MODIFY | NFS_ACCESS_EXTEND;
+	if (S_ISDIR(inode->i_mode))
+		cache.mask |= NFS_ACCESS_DELETE | NFS_ACCESS_LOOKUP;
+	else
+		cache.mask |= NFS_ACCESS_EXECUTE;
 	cache.cred = cred;
 	status = NFS_PROTO(inode)->access(inode, &cache);
 	if (status != 0) {

fs/nfs/nfs3proc.c

@@ -187,6 +187,7 @@ static int nfs3_proc_access(struct inode *inode, struct nfs_access_entry *entry)
 {
 	struct nfs3_accessargs	arg = {
 		.fh		= NFS_FH(inode),
+		.access		= entry->mask,
 	};
 	struct nfs3_accessres	res;
 	struct rpc_message msg = {
@@ -195,25 +196,9 @@ static int nfs3_proc_access(struct inode *inode, struct nfs_access_entry *entry)
 		.rpc_resp	= &res,
 		.rpc_cred	= entry->cred,
 	};
-	int mode = entry->mask;
 	int status = -ENOMEM;
 
 	dprintk("NFS call  access\n");
-
-	if (mode & MAY_READ)
-		arg.access |= NFS3_ACCESS_READ;
-	if (S_ISDIR(inode->i_mode)) {
-		if (mode & MAY_WRITE)
-			arg.access |= NFS3_ACCESS_MODIFY | NFS3_ACCESS_EXTEND | NFS3_ACCESS_DELETE;
-		if (mode & MAY_EXEC)
-			arg.access |= NFS3_ACCESS_LOOKUP;
-	} else {
-		if (mode & MAY_WRITE)
-			arg.access |= NFS3_ACCESS_MODIFY | NFS3_ACCESS_EXTEND;
-		if (mode & MAY_EXEC)
-			arg.access |= NFS3_ACCESS_EXECUTE;
-	}
-
 	res.fattr = nfs_alloc_fattr();
 	if (res.fattr == NULL)
 		goto out;

fs/nfs/nfs4proc.c

@@ -3889,6 +3889,7 @@ static int _nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry
 	struct nfs4_accessargs args = {
 		.fh = NFS_FH(inode),
 		.bitmask = server->cache_consistency_bitmask,
+		.access = entry->mask,
 	};
 	struct nfs4_accessres res = {
 		.server = server,
@@ -3899,26 +3900,8 @@ static int _nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry
 		.rpc_resp = &res,
 		.rpc_cred = entry->cred,
 	};
-	int mode = entry->mask;
 	int status = 0;
 
-	/*
-	 * Determine which access bits we want to ask for...
-	 */
-	if (mode & MAY_READ)
-		args.access |= NFS4_ACCESS_READ;
-	if (S_ISDIR(inode->i_mode)) {
-		if (mode & MAY_WRITE)
-			args.access |= NFS4_ACCESS_MODIFY | NFS4_ACCESS_EXTEND | NFS4_ACCESS_DELETE;
-		if (mode & MAY_EXEC)
-			args.access |= NFS4_ACCESS_LOOKUP;
-	} else {
-		if (mode & MAY_WRITE)
-			args.access |= NFS4_ACCESS_MODIFY | NFS4_ACCESS_EXTEND;
-		if (mode & MAY_EXEC)
-			args.access |= NFS4_ACCESS_EXECUTE;
-	}
-
 	res.fattr = nfs_alloc_fattr();
 	if (res.fattr == NULL)
 		return -ENOMEM;