linux-ext4 - Re: [PATCH] fs/jbd2: t_updates should increase when start_this_handle() failed in jbd2__journal

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 25 Jun 2013 16:30:18 +0800
From:	Younger Liu <younger.liu@...wei.com>
To:	"Theodore Ts'o" <tytso@....edu>
CC:	Andrew Morton <akpm@...ux-foundation.org>,
	<linux-ext4@...r.kernel.org>,
	Ocfs2-Devel <ocfs2-devel@....oracle.com>,
	Li Zefan <lizefan@...wei.com>, <jack@...e.cz>
Subject: Re: [PATCH] fs/jbd2: t_updates should increase when start_this_handle()
 failed in jbd2__journal_restart()

I will check and test the pacth.

I only merge the patch about " jbd2: invalidate handle if 
jbd2_journal_restart() fails" int my source. But I do not 
merge the patch about "jbd2: Transaction reservation support...".

Does it affect the test?

On 2013/6/24 1:36, Theodore Ts'o wrote:
> On Fri, Jun 21, 2013 at 09:29:31PM +0800, Younger Liu wrote:
>>
>> This bug was triggered by the following scenario:
>> In ocfs2 file system, allocate a very large disk space for a small file
>> with ocfs2_fallocate(), while the journal file size is 32M. 
>>
>> Because there are much many journal blocks needed by jbd2_journal_restart(), 
>> so that nblocks is greater than journal->j_max_transaction_buffers 
>> in start_this_handle(), and then return -ENOSPC.
> 
> Ah, I see.  I have a patch that should prevent the kernel from
> crashing in this situation, and which adds some additional checks to
> make sure no one tries to use the handle after jbd2_journal_restart()
> fails in this circumstance.
> 
> However, you may want to further pursue a fix in ocfs2 so you don't
> actually return ENOSPC to userspace, since it is a very misleading
> error message --- it's not that the file system is out of space, but
> that the journal is too small for the amount of space that you are
> trying to allocate using fallocate().
> 
> I would think a better way of handling this situation would be to log
> a warning message that the journal is probably too small, and then to
> break up the fallocate into smaller chunks, so that it can
> successfully complete despite the fact that the journal was
> unfortunately missized.
> 
> I'll be sending the proposed fix in a moment; could you check and see
> if the patch prevents ocfs2/jbd2 from tripping over the assertion
> given your test case?
> 
> Thanks,
> 
> 					- Ted
> 
> .
> 

--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html