From: Christoph Hellwig <hch@infradead.org>
To: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <jens.axboe@oracle.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
chris.mason@oracle.com, david@fromorbit.com, hch@infradead.org,
akpm@linux-foundation.org, yanmin_zhang@linux.intel.com,
richard@rsk.demon.co.uk, damien.wyart@free.fr,
fweisbec@gmail.com, Alan.Brunelle@hp.com
Subject: Re: [PATCH 2/9] writeback: switch to per-bdi threads for flushing data
Date: Thu, 6 Aug 2009 17:44:33 -0400 [thread overview]
Message-ID: <20090806214433.GA866@infradead.org> (raw)
In-Reply-To: <20090805163532.GC27505@duck.suse.cz>
On Wed, Aug 05, 2009 at 06:35:32PM +0200, Jan Kara wrote:
> Jens, sorry about bitching about this again but you're silently changing
> substantial locking assumptions without writing it *anywhere* and without
> arguing it's safe.
> Originally, generic_sync_sb_inodes() from writeback path have been
> called with
> a) s_umount_sem held
> b) sb->s_count elevated
> The second still seems to be true since, if I'm right, we pass here
> non-NULL sb only from sync_filesystem() and that takes care of the
> superblock reference. So that is just a matter of documenting this fact
> before the function.
We'll defintively need to keep both to prevent races vs unmount. And
with a NULL superblock passed I'm not even sure how we can take care of
it.
next prev parent reply other threads:[~2009-08-06 21:44 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-30 21:23 [PATCH 0/9] Per-bdi writeback flusher threads v13 Jens Axboe
2009-07-30 21:23 ` [PATCH 1/9] writeback: move dirty inodes from super_block to backing_dev_info Jens Axboe
2009-08-06 21:35 ` Christoph Hellwig
2009-08-12 16:12 ` Jens Axboe
2009-08-12 16:18 ` Jens Axboe
2009-08-28 20:29 ` Christoph Hellwig
2009-07-30 21:23 ` [PATCH 2/9] writeback: switch to per-bdi threads for flushing data Jens Axboe
2009-08-05 16:35 ` Jan Kara
2009-08-06 21:44 ` Christoph Hellwig [this message]
2009-07-30 21:23 ` [PATCH 3/9] writeback: get rid of pdflush completely Jens Axboe
2009-07-30 21:23 ` [PATCH 4/9] writeback: separate the flushing state/task from the bdi Jens Axboe
2009-07-30 21:24 ` [PATCH 5/9] writeback: support > 1 flusher thread per bdi Jens Axboe
2009-08-05 19:55 ` Jan Kara
2009-08-06 7:05 ` Jens Axboe
2009-08-06 20:56 ` Jan Kara
2009-08-24 11:43 ` Jens Axboe
2009-08-24 12:36 ` Jan Kara
2009-08-24 14:09 ` Jens Axboe
2009-08-06 21:33 ` Christoph Hellwig
2009-07-30 21:24 ` [PATCH 6/9] writeback: allow sleepy exit of default writeback task Jens Axboe
2009-08-05 19:57 ` Jan Kara
2009-08-06 7:03 ` Jens Axboe
2009-08-06 18:55 ` Jan Kara
2009-07-30 21:24 ` [PATCH 7/9] writeback: add some debug inode list counters to bdi stats Jens Axboe
2009-07-30 21:24 ` [PATCH 8/9] writeback: add name to backing_dev_info Jens Axboe
2009-07-30 21:24 ` [PATCH 9/9] writeback: check for registered bdi in flusher add and inode dirty Jens Axboe
2009-07-31 6:30 ` [PATCH 0/9] Per-bdi writeback flusher threads v13 Damien Wyart
2009-07-31 7:15 ` Jens Axboe
2009-08-03 19:29 ` Damien Wyart
2009-08-03 20:28 ` Jens Axboe
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