From: Gao Xiang gaoxiang25@huawei.com

As David reported [1], ENODATA returns when attempting to modify files by using EROFS as a overlayfs lower layer.

The root cause is that listxattr could return unexpected -ENODATA by mistake for inodes without xattr. That breaks listxattr return value convention and it can cause copy up failure when used with overlayfs.

Resolve by zeroing out if no xattr is found for listxattr.

[1] https://lore.kernel.org/r/CAEvUa7nxnby+rxK-KRMA46=exeOMApkDMAV08AjMkkPnTPV4C... Fixes: cadf1ccf1b00 ("staging: erofs: add error handling for xattr submodule") Cc: stable@vger.kernel.org # 4.19+ Signed-off-by: Gao Xiang gaoxiang25@huawei.com --- fs/erofs/xattr.c | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c index a13a78725c57..b766c3ee5fa8 100644 --- a/fs/erofs/xattr.c +++ b/fs/erofs/xattr.c @@ -649,6 +649,8 @@ ssize_t erofs_listxattr(struct dentry *dentry, struct listxattr_iter it;

ret = init_inode_xattrs(d_inode(dentry)); + if (ret == -ENOATTR) + return 0; if (ret) return ret;