mkfs.ubifs: make failure to list extended attributes quiet and non-fatal

mkfs.ubifs treats all errors returned by llistxattr() except ENOENT as fatal. In particular, if the host system doesn't support extended attributes, mkfs.ubifs would fail. It happens even without any flags that would explicitly request extended attribute support.

As a result, it's impossible to build an OpenEmbedded based UBI image on a system without extended attribute support if the xattr feature is enabled in DISTRO_FEATURES.

Take a clue from mkfs.jffs2, which treats llistxattr() errors as non-fatal and doesn't report them by default. Report the error at the debug level 1 and higher.

The second llistxattr() error remains fatal, as it indicates unexpected behavior.

Don't use goto before the buffer is allocated. Don't initialize buf with NULL, it should not be used before the xmalloc() call.

---
 ubifs-utils/mkfs.ubifs/mkfs.ubifs.c | 21 ++++++---------------
 1 file changed, 6 insertions(+), 15 deletions(-)

index d432dfe..e390b5a 100644
@@ -1122,22 +1122,17 @@ static int inode_add_xattr(struct ubifs_ino_node *host_ino,
 {
 	int ret;
 	struct qstr nm;
-	void *buf = NULL;
+	void *buf;
 	ssize_t len;
 	ssize_t pos = 0;
 
 	len = llistxattr(path_name, NULL, 0);
-	if (len < 0) {
-		if (errno == ENOENT)
-			return 0;
-
-		sys_err_msg("llistxattr failed on %s", path_name);
-
-		return len;
-	}
+	if (len < 0)
+		dbg_msg(1, "llistxattr('%s') = %d : %s\n", path_name,
+			errno, strerror(errno));
 
-	if (len == 0)
-		goto noxattr;
+	if (len <= 0)
+		return 0;
 
 	buf = xmalloc(len);
 

@@ -1191,10 +1186,6 @@ static int inode_add_xattr(struct ubifs_ino_node *host_ino,
 			goto out_free;
 	}
 
-noxattr:
-	free(buf);
-	return 0;
-
 out_free:
 	free(buf);
 

2.14.2

Hi,

Would it also work if we simply extended the check you patched to test for ENOTSUP in addition?

Thanks,

David

Hello David,

Yes, that would work. I checked the OpenEmbedded build with the new patch, it passes. The error is called EOPNOTSUPP. I can submit the patch if that's the approach you prefer.

Regards,
Pavel Roskin