From: Chao Yu <chao@kernel.org>
To: Matthew Wilcox <willy@infradead.org>, Gao Xiang <hsiangkao@aol.com>
Cc: Chao Yu <yuchao0@huawei.com>, Richard Weinberger <richard@nod.at>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
devel@driverdev.osuosl.org, linux-fsdevel@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>,
linux-erofs@lists.ozlabs.org, Miao Xie <miaoxie@huawei.com>,
Fang Wei <fangwei1@huawei.com>, Gao Xiang <gaoxiang25@huawei.com>,
stable@vger.kernel.org
Subject: Re: [PATCH v2] staging: erofs: fix an error handling in erofs_readdir()
Date: Sun, 18 Aug 2019 18:39:52 +0800 [thread overview]
Message-ID: <c624d057-cd42-515c-cff8-cf68340401e0@kernel.org> (raw)
In-Reply-To: <20190818025339.GB14592@bombadil.infradead.org>
On 2019-8-18 10:53, Matthew Wilcox wrote:
> On Sun, Aug 18, 2019 at 10:32:45AM +0800, Gao Xiang wrote:
>> On Sat, Aug 17, 2019 at 07:20:55PM -0700, Matthew Wilcox wrote:
>>> On Sun, Aug 18, 2019 at 09:56:31AM +0800, Gao Xiang wrote:
>>>> @@ -82,8 +82,12 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx)
>>>> unsigned int nameoff, maxsize;
>>>>
>>>> dentry_page = read_mapping_page(mapping, i, NULL);
>>>> - if (IS_ERR(dentry_page))
>>>> - continue;
>>>> + if (IS_ERR(dentry_page)) {
>>>> + errln("fail to readdir of logical block %u of nid %llu",
>>>> + i, EROFS_V(dir)->nid);
>>>> + err = PTR_ERR(dentry_page);
>>>> + break;
>>>
>>> I don't think you want to use the errno that came back from
>>> read_mapping_page() (which is, I think, always going to be -EIO).
>>> Rather you want -EFSCORRUPTED, at least if I understand the recent
>>> patches to ext2/ext4/f2fs/xfs/...
>>
>> Thanks for your reply and noticing this. :)
>>
>> Yes, as I talked with you about read_mapping_page() in a xfs related
>> topic earlier, I think I fully understand what returns here.
>>
>> I actually had some concern about that before sending out this patch.
>> You know the status is
>> PG_uptodate is not set and PG_error is set here.
>>
>> But we cannot know it is actually a disk read error or due to
>> corrupted images (due to lack of page flags or some status, and
>> I think it could be a waste of page structure space for such
>> corrupted image or disk error)...
>>
>> And some people also like propagate errors from insiders...
>> (and they could argue about err = -EFSCORRUPTED as well..)
>>
>> I'd like hear your suggestion about this after my words above?
>> still return -EFSCORRUPTED?
>
> I don't think it matters whether it's due to a disk error or a corrupted
> image. We can't read the directory entry, so we should probably return
> -EFSCORRUPTED. Thinking about it some more, read_mapping_page() can
> also return -ENOMEM, so it should probably look something like this:
>
> err = 0;
> if (dentry_page == ERR_PTR(-ENOMEM))
> err = -ENOMEM;
> else if (IS_ERR(dentry_page)) {
> errln("fail to readdir of logical block %u of nid %llu",
> i, EROFS_V(dir)->nid);
> err = -EFSCORRUPTED;
Well, if there is real IO error happen under filesystem, we should return -EIO
instead of EFSCORRUPTED?
The right fix may be that doing sanity check on on-disk blkaddr, and return
-EFSCORRUPTED if the blkaddr is invalid and propagate the error to its caller
erofs_readdir(), IIUC below error info.
> [36297.354090] attempt to access beyond end of device
> [36297.354098] loop17: rw=0, want=29887428984, limit=1953128
> [36297.354107] attempt to access beyond end of device
> [36297.354109] loop17: rw=0, want=29887428480, limit=1953128
> [36301.827234] attempt to access beyond end of device
> [36301.827243] loop17: rw=0, want=29887428480, limit=1953128
Thanks,
> }
>
> if (err)
> break;
>
next prev parent reply other threads:[~2019-08-18 10:40 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-18 1:48 [PATCH] staging: erofs: fix an error handling in erofs_readdir() Gao Xiang
2019-08-18 1:56 ` [PATCH v2] " Gao Xiang
2019-08-18 2:20 ` Matthew Wilcox
2019-08-18 2:32 ` Gao Xiang
2019-08-18 2:53 ` Matthew Wilcox
2019-08-18 3:01 ` Gao Xiang
2019-08-18 3:18 ` [PATCH] " Gao Xiang
2019-08-18 12:07 ` kbuild test robot
2019-08-18 13:17 ` kbuild test robot
2019-08-18 13:25 ` Gao Xiang
2019-08-20 6:50 ` Philip Li
2019-08-20 6:50 ` Gao Xiang
2019-08-20 6:58 ` Li, Philip
2019-08-20 7:16 ` Gao Xiang
2019-08-18 3:21 ` [PATCH v3 RESEND] " Gao Xiang
2019-08-18 8:33 ` Richard Weinberger
2019-08-18 9:10 ` Gao Xiang
2019-08-18 9:18 ` [PATCH v3 RESEND] staging: erofs: fix an error handling in erofs_readdir()y Gao Xiang
2019-08-18 12:29 ` [PATCH v3 RESEND] staging: erofs: fix an error handling in erofs_readdir() Chao Yu
2019-08-18 12:33 ` Matthew Wilcox
2019-08-18 12:38 ` Gao Xiang
2019-08-18 12:54 ` [PATCH v4] " Gao Xiang
2019-08-18 10:39 ` Chao Yu [this message]
2019-08-18 10:52 ` [PATCH v2] " Gao Xiang
2019-08-18 12:28 ` Chao Yu
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