knfsd: nfsd4: fix handling of acl errrors

nfs4_acl_nfsv4_to_posix() returns an error and returns any posix acls
calculated in two caller-provided pointers.  It was setting these pointers to
-errno in some error cases, resulting in nfsd4_set_nfs4_acl() calling
posix_acl_release() with a -errno as an argument.

Fix both the caller and the callee, by modifying nfsd4_set_nfs4_acl() to
stop relying on the passed-in-pointers being left as NULL in the error
case, and by modifying nfs4_acl_nfsv4_to_posix() to stop returning
garbage in those pointers.

Thanks to Alex Soule for reporting the bug.
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Cc: Alexander Soule <soule@umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/nfsd/nfs4acl.c

@@ -737,13 +737,16 @@ int nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl, struct posix_acl **pacl,
 	*pacl = posix_state_to_acl(&effective_acl_state, flags);
 	if (IS_ERR(*pacl)) {
 		ret = PTR_ERR(*pacl);
+		*pacl = NULL;
 		goto out_dstate;
 	}
 	*dpacl = posix_state_to_acl(&default_acl_state,
 						flags | NFS4_ACL_TYPE_DEFAULT);
 	if (IS_ERR(*dpacl)) {
 		ret = PTR_ERR(*dpacl);
+		*dpacl = NULL;
 		posix_acl_release(*pacl);
+		*pacl = NULL;
 		goto out_dstate;
 	}
 	sort_pacl(*pacl);

fs/nfsd/vfs.c

@@ -435,7 +435,7 @@ nfsd4_set_nfs4_acl(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	/* Get inode */
 	error = fh_verify(rqstp, fhp, 0 /* S_IFREG */, MAY_SATTR);
 	if (error)
-		goto out;
+		return error;
 
 	dentry = fhp->fh_dentry;
 	inode = dentry->d_inode;
@@ -444,33 +444,25 @@ nfsd4_set_nfs4_acl(struct svc_rqst *rqstp, struct svc_fh *fhp,
 
 	host_error = nfs4_acl_nfsv4_to_posix(acl, &pacl, &dpacl, flags);
 	if (host_error == -EINVAL) {
-		error = nfserr_attrnotsupp;
-		goto out;
+		return nfserr_attrnotsupp;
 	} else if (host_error < 0)
 		goto out_nfserr;
 
 	host_error = set_nfsv4_acl_one(dentry, pacl, POSIX_ACL_XATTR_ACCESS);
 	if (host_error < 0)
-		goto out_nfserr;
+		goto out_release;
 
-	if (S_ISDIR(inode->i_mode)) {
+	if (S_ISDIR(inode->i_mode))
 		host_error = set_nfsv4_acl_one(dentry, dpacl, POSIX_ACL_XATTR_DEFAULT);
-		if (host_error < 0)
-			goto out_nfserr;
-	}
-
-	error = nfs_ok;
 
-out:
+out_release:
 	posix_acl_release(pacl);
 	posix_acl_release(dpacl);
-	return (error);
 out_nfserr:
 	if (host_error == -EOPNOTSUPP)
-		error = nfserr_attrnotsupp;
+		return nfserr_attrnotsupp;
 	else
-		error = nfserrno(host_error);
-	goto out;
+		return nfserrno(host_error);
 }
 
 static struct posix_acl *