[PATCH] erofs: zero out when listxattr is called with no xattr

[Chao Yu]

On 2019/12/1 16:40, Gao Xiang wrote:
> From: Gao Xiang <gaoxiang25 at 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=exeOMApkDMAV08AjMkkPnTPV4CQ@mail.gmail.com
> Fixes: cadf1ccf1b00 ("staging: erofs: add error handling for xattr submodule")
> Cc: <stable at vger.kernel.org> # 4.19+
> Signed-off-by: Gao Xiang <gaoxiang25 at huawei.com>

Reviewed-by: Chao Yu <yuchao0 at huawei.com>

Thanks,