From: Ted Ts'o <tytso@mit.edu>
To: Jan Kara <jack@suse.cz>
Cc: Sami Liedes <sami.liedes@iki.fi>,
linux-ext4@vger.kernel.org, linux-fsdev@vger.kernel.org,
Al Viro <viro@ZenIV.linux.org.uk>
Subject: Re: ext2 hang on (intentionally) corrupted filesystem
Date: Mon, 28 May 2012 13:31:33 -0400 [thread overview]
Message-ID: <20120528173133.GA31109@thunk.org> (raw)
In-Reply-To: <20120509211236.GI5092@quack.suse.cz>
On Wed, May 09, 2012 at 11:12:36PM +0200, Jan Kara wrote:
> > 1. wget http://sli.dy.fi/~sliedes/berserker/testcases/ext2.110.min.bz2
> > 2. mount ... /mnt -t ext2 -o errors=continue
> > 3. Do some operations; what I do (it's the rm that crashes):
> > timeout 30 rm -rf /mnt/* >&/dev/null
> > 4. The rm task hangs
> >
> OK, you've changed '.' directory entry to a normal directory entry with a
> name 0x6e. I guess that has some potential in confusing something. Actually
> rm -rf does not reproduce the problem for me (it just complains about
> cyclic directory hierarchy) but trying to rmdir bad entry hangs the system
> - we try to grab i_mutex for the directory twice because the directory is
> it's own parent... That would be kind of hard to fix in VFS since once our
> directory structure contains a cycle, our locking protocol is no longer
> deadlock free. I'll see what we could do...
Just wanted to chime in that this crashes when the file system is
mounted using ext4; not surprising, since it's clearly a VFS issue.
The following proof-of-concept patch (see reply chained to this mail
message) fixes the problem for your test file system. Al, what do you
think? Is it worth it to define a new mechanism where we can pass
VFS-detected corruption down to the low-level file system?
- Ted
next prev parent reply other threads:[~2012-05-28 17:31 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-05 1:38 ext2 hang on (intentionally) corrupted filesystem Sami Liedes
2012-05-09 21:12 ` Jan Kara
2012-05-28 17:31 ` Ted Ts'o [this message]
2012-05-28 17:34 ` [PATCH] vfs: avoid hang caused by attempting to rmdir an invalid file system Theodore Ts'o
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=20120528173133.GA31109@thunk.org \
--to=tytso@mit.edu \
--cc=jack@suse.cz \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-fsdev@vger.kernel.org \
--cc=sami.liedes@iki.fi \
--cc=viro@ZenIV.linux.org.uk \
/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).