All of lore.kernel.org
 help / color / mirror / Atom feed
From: Max Kellermann <mk@cm4all.com>
To: David Howells <dhowells@redhat.com>
Cc: Max Kellermann <mk@cm4all.com>,
	linux-cachefs@redhat.com, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: fscache corruption in Linux 5.17?
Date: Tue, 19 Apr 2022 18:06:19 +0200	[thread overview]
Message-ID: <Yl7d++G25sNXIR+p@rabbit.intern.cm-ag> (raw)
In-Reply-To: <507518.1650383808@warthog.procyon.org.uk>

On 2022/04/19 17:56, David Howells <dhowells@redhat.com> wrote:
> This is weird.  It looks like content got slid down by 31 bytes and 31 zero
> bytes got added at the end.  I'm not sure how fscache would achieve that -
> nfs's implementation should only be dealing with pages.

Did you read this part of my email?:

On 2022/04/12 17:10, Max Kellermann <max@rabbit.intern.cm-ag> wrote:
> The corruption can be explained by WordPress commit
> https://github.com/WordPress/WordPress/commit/07855db0ee8d5cff2 which
> makes the file 31 bytes longer (185055 -> 185086).  The "broken" web
> server sees the new contents until offset 184320 (= 45 * 4096), but
> sees the old contents from there on; followed by 31 null bytes
> (because the kernel reads past the end of the cache?).

My theory was that fscache shows a mix of old and new pages after the
file was modified.  Does this make sense?

Is there anything I can do to give you data from this server's cache?

  reply	other threads:[~2022-04-19 16:06 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-12 15:10 fscache corruption in Linux 5.17? Max Kellermann
2022-04-16 11:38 ` Thorsten Leemhuis
2022-04-16 19:55   ` Max Kellermann
2022-04-19 13:02 ` David Howells
2022-04-19 14:18   ` Max Kellermann
2022-04-19 15:23     ` [Linux-cachefs] " David Wysochanski
2022-04-19 16:17   ` David Howells
2022-04-19 16:41     ` Max Kellermann
2022-04-19 16:47     ` David Howells
2022-04-19 15:56 ` David Howells
2022-04-19 16:06   ` Max Kellermann [this message]
2022-04-19 16:42   ` David Howells
2022-04-19 18:01     ` Max Kellermann
2022-04-19 21:27     ` Max Kellermann
2022-04-20 13:55     ` David Howells
2022-05-04  8:38       ` Max Kellermann
2022-05-31  8:35       ` David Howells
2022-05-31  8:41         ` Max Kellermann
2022-05-31  9:13         ` David Howells
2022-06-20  7:11           ` Thorsten Leemhuis

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=Yl7d++G25sNXIR+p@rabbit.intern.cm-ag \
    --to=mk@cm4all.com \
    --cc=dhowells@redhat.com \
    --cc=linux-cachefs@redhat.com \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.