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Subject: Re: [PATCH] erofs: zero out when listxattr is called with no xattr
To:     Gao Xiang <hsiangkao@aol.com>, <linux-erofs@lists.ozlabs.org>
CC:     LKML <linux-kernel@vger.kernel.org>,
        David Michael <fedora.dm0@gmail.com>,
        Miao Xie <miaoxie@huawei.com>, Fang Wei <fangwei1@huawei.com>,
        Wang Li <wangli74@huawei.com>,
        Gao Xiang <gaoxiang25@huawei.com>, <stable@vger.kernel.org>
References: <20191201084040.29275-1-hsiangkao.ref@aol.com>
 <20191201084040.29275-1-hsiangkao@aol.com>
From:   Chao Yu <yuchao0@huawei.com>
Message-ID: <947ae429-d206-0859-ee5b-9bd37f7fd72b@huawei.com>
Date:   Wed, 4 Dec 2019 11:14:37 +0800
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On 2019/12/1 16:40, Gao Xiang wrote:
> 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=exeOMApkDMAV08AjMkkPnTPV4CQ@mail.gmail.com
> 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>

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

Thanks,