[added to the 4.1 stable tree] ovl: allow zero size xattr

From: Miklos Szeredi <miklos@szeredi.hu>

This patch has been added to the 4.1 stable tree. If you have any
objections, please let us know.

===============

[ Upstream commit 97daf8b97ad6f913a34c82515be64dc9ac08d63e ]

When ovl_copy_xattr() encountered a zero size xattr no more xattrs were
copied and the function returned success.  This is clearly not the desired
behavior.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Cc: <redacted>
Signed-off-by: Sasha Levin <redacted>
---
 fs/overlayfs/copy_up.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 871fcb6..394e87f 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c

@@ -54,7 +54,7 @@ int ovl_copy_xattr(struct dentry *old, struct dentry *new)
 
 	for (name = buf; name < (buf + list_size); name += strlen(name) + 1) {
 		size = vfs_getxattr(old, name, value, XATTR_SIZE_MAX);
-		if (size <= 0) {
+		if (size < 0) {
 			error = size;
 			goto out_free_value;
 		}

-- 
2.5.0