From: David Laight <David.Laight@ACULAB.COM>
To: 'Chao Yu' <yuchao0@huawei.com>, Jaegeuk Kim <jaegeuk@kernel.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-f2fs-devel@lists.sourceforge.net"
<linux-f2fs-devel@lists.sourceforge.net>
Subject: Re: [f2fs-dev] [PATCH] f2fs: compress: support chksum
Date: Tue, 3 Nov 2020 10:35:13 +0000 [thread overview]
Message-ID: <aa11afd31edb42979c03d2a27ed9e850@AcuMS.aculab.com> (raw)
In-Reply-To: <6b5bce0e-c967-b9cf-3544-a8e65595059c@huawei.com>
From: Chao Yu
> Sent: 03 November 2020 02:37
...
> >> Do we need to change fsck.f2fs to recover this?
>
> However, we don't know which one is correct, compressed data or chksum value?
> if compressed data was corrupted, repairing chksum value doesn't help.
>
> Or how about adding chksum values for both raw data and compressed data.
What errors are you trying to detect?
If there are errors in the data then 'fixing' the checksum is pointless.
(You've got garbage data - might as well not have the checksum).
If you are worried about the implementation of the compression
algorithm then a checksum of the raw data is needed.
If you want to try error correcting burst errors in the compressed
data then a crc of the compressed data can be used for error correction.
OTOH the most likely error is that the file meta-data and data sector
weren't both committed to disk when the system crashed.
In which case the checksum has done its job and the file is corrupt.
fsck should probably move the file to 'lost+found' for manual checking.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
next prev parent reply other threads:[~2020-11-03 10:51 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-02 12:23 [f2fs-dev] [PATCH] f2fs: compress: support chksum Chao Yu
2020-11-02 16:31 ` Jaegeuk Kim
2020-11-03 2:02 ` Chao Yu
2020-11-03 2:36 ` Chao Yu
2020-11-03 10:35 ` David Laight [this message]
2020-11-03 11:51 ` Chao Yu
2020-11-05 1:13 ` Chao Yu
2020-11-06 21:12 ` Jaegeuk Kim
2020-11-09 1:49 ` Chao Yu
2020-11-09 17:06 ` Jaegeuk Kim
2020-11-10 1:52 ` Chao Yu
2020-11-10 4:23 ` Jaegeuk Kim
2020-11-10 6:27 ` Chao Yu
2020-11-10 12:16 ` David Laight
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=aa11afd31edb42979c03d2a27ed9e850@AcuMS.aculab.com \
--to=david.laight@aculab.com \
--cc=jaegeuk@kernel.org \
--cc=linux-f2fs-devel@lists.sourceforge.net \
--cc=linux-kernel@vger.kernel.org \
--cc=yuchao0@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).