From: Jens Axboe <jens.axboe@oracle.com>
To: Jan Kara <jack@suse.cz>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
chris.mason@oracle.com, hch@infradead.org, tytso@mit.edu,
akpm@linux-foundation.org, trond.myklebust@fys.uio.no
Subject: Re: [PATCH 10/16] writeback: splice dirty inode entries to default bdi on bdi_destroy()
Date: Wed, 16 Sep 2009 20:29:32 +0200 [thread overview]
Message-ID: <20090916182932.GR23126@kernel.dk> (raw)
In-Reply-To: <20090916134346.GM26030@duck.suse.cz>
On Wed, Sep 16 2009, Jan Kara wrote:
> On Wed 16-09-09 15:24:48, Jens Axboe wrote:
> > We cannot safely ensure that the inodes are all gone at this point
> > in time, and we must not destroy this bdi with inodes having off it.
> > So just splice our entries to the default bdi since that one will
> > always persist.
> I'd at least add a comment like
> "XXX: This is probably a bug but let's workaround it for now."
> And either remove the code or update the comment when this gets resolved.
Thinking more about it - what if inodes happen to get requeued on the
final flush? bdi_destroy() likely can't wait for flushing to happen,
since (depending on the tear down cycle), part of the device may be gone
already.
And I did mean __sync_filesystem() -> __sync_blockdev(), since this is
what happen on last close. So it could also be that we need something
stronger to guarantee that things are really gone.
--
Jens Axboe
next prev parent reply other threads:[~2009-09-16 18:29 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-16 13:24 [PATCH 0/16] Post merge per-bdi writeback patches v4 Jens Axboe
2009-09-16 13:24 ` [PATCH 01/16] fs: remove bdev->bd_inode_backing_dev_info Jens Axboe
2009-09-16 13:24 ` [PATCH 02/16] writeback: get rid of wbc->for_writepages Jens Axboe
2009-09-16 13:24 ` [PATCH 03/16] writeback: merely wakeup flusher thread if work allocation fails for WB_SYNC_NONE Jens Axboe
2009-09-16 13:24 ` [PATCH 04/16] writeback: make wb_writeback() take an argument structure Jens Axboe
2009-09-16 13:32 ` Jan Kara
2009-09-16 13:24 ` [PATCH 05/16] fs: Assign bdi in super_block Jens Axboe
2009-09-16 13:34 ` Jan Kara
2009-09-16 13:24 ` [PATCH 06/16] writeback: only use bdi_writeback_all() for WB_SYNC_NONE writeout Jens Axboe
2009-09-16 13:24 ` [PATCH 07/16] writeback: use RCU to protect bdi_list Jens Axboe
2009-09-16 13:24 ` [PATCH 08/16] writeback: inline allocation failure handling in bdi_alloc_queue_work() Jens Axboe
2009-09-16 13:24 ` [PATCH 09/16] writeback: separate starting of sync vs opportunistic writeback Jens Axboe
2009-09-16 13:36 ` Jan Kara
2009-09-16 13:24 ` [PATCH 10/16] writeback: splice dirty inode entries to default bdi on bdi_destroy() Jens Axboe
2009-09-16 13:43 ` Jan Kara
2009-09-16 18:29 ` Jens Axboe [this message]
2009-09-17 9:22 ` Jan Kara
2009-09-16 13:24 ` [PATCH 11/16] writeback: add comments to bdi_work structure Jens Axboe
2009-09-16 13:24 ` [PATCH 12/16] writeback: use schedule_timeout_interruptible() Jens Axboe
2009-09-16 13:24 ` [PATCH 13/16] writeback: remove smp_mb(), it's not needed with list_add_tail_rcu() Jens Axboe
2009-09-16 13:24 ` [PATCH 14/16] writeback: improve scalability of bdi writeback work queues Jens Axboe
2009-09-16 13:24 ` [PATCH 15/16] writeback: Fix bdi use after free in wb_work_complete() Jens Axboe
2009-09-16 13:24 ` [PATCH 16/16] writeback: fix possible bdi writeback refcounting problem Jens Axboe
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