linux-ext4 - Re: [PATCH v2 2/3] jbd2: Add extra parameter in start_this

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 PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

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

Date:	Tue, 31 May 2011 18:27:20 -0400
From:	Ted Ts'o <tytso@....edu>
To:	Jan Kara <jack@...e.cz>
Cc:	Manish Katiyar <mkatiyar@...il.com>, linux-ext4@...r.kernel.org,
	mfasheh@...e.com, jlbec@...lplan.org
Subject: Re: [PATCH v2 2/3] jbd2: Add extra parameter in
 start_this_handle() to control allocation flags.

On Tue, May 31, 2011 at 01:22:53PM +0200, Jan Kara wrote:
> 
> The problem is that with ext4, we need i_mutex in io completion path to
> end page writeback. So we cannot do GFP_KERNEL allocation whenever we hold
> i_mutex because mm might wait in direct reclaim for IO to complete and that
> cannot happen until we release i_mutex. 

OK, maybe I'm being dense, but I'm not seeing it.  I see where we need
i_mutex on the ext4_da_writepages() codepath, but that's never used
for direct reclaim.  Direct reclaim only calls ext4_writepage(), and
that doesn't seem to try to grab i_mutex as near as I can tell.  Am I
missing something?

						- 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