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From: Christoph Hellwig <hch@infradead.org>
To: Nick Piggin <npiggin@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [patch 8/8] fs: add i_op->sync_inode
Date: Fri, 7 Jan 2011 02:29:34 -0500	[thread overview]
Message-ID: <20110107072934.GA2849@infradead.org> (raw)
In-Reply-To: <20110107072430.GA32308@infradead.org>

On Fri, Jan 07, 2011 at 02:24:30AM -0500, Christoph Hellwig wrote:
> On Fri, Jan 07, 2011 at 03:47:34PM +1100, Nick Piggin wrote:
> > No, you misunderstand 1. I am saying they should be treated as
> > WB_SYNC_NONE.
> > 
> > In fact 2 would cause much more IO, because dirty writeout would
> > never clean them so it will just keep writing them out. I don't
> > know how 2 could be feasible.
> 
> WB_SYNC_NONE means ->write_inode behaves non-blocking.  That is
> we do not block on memory allocations, and we do not take locks
> blocking.  Most journaling filesystems currently take the easy
> way out an make it a no-op due to that, but take a look at XFS
> how complicated it is to avoid the blocking if you want a non-noop
> implementation.

Btw, there's an easy way how we could get this right, in fact
the write_inode in XFS is already trying to do it, it's just the
caller not copying with it:

 - if we can't get locks for a non-blocking ->write_inode we return
   EAGAIN, and the callers sets the dirty bits again.

  reply	other threads:[~2011-01-07  7:29 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-12-18  1:46 [patch 0/8] Inode data integrity patches Nick Piggin
2010-12-18  1:46 ` [patch 1/8] fs: mark_inode_dirty barrier fix Nick Piggin
2010-12-18  1:46 ` [patch 2/8] fs: simple fsync race fix Nick Piggin
2010-12-18  1:46 ` [patch 3/8] fs: introduce inode writeback helpers Nick Piggin
2010-12-18  1:46 ` [patch 4/8] fs: preserve inode dirty bits on failed metadata writeback Nick Piggin
2010-12-18  1:46 ` [patch 5/8] fs: ext2 inode sync fix Nick Piggin
2011-01-07 19:08   ` Ted Ts'o
2010-12-18  1:46 ` [patch 6/8] fs: fsync optimisations Nick Piggin
2010-12-18  1:46 ` [patch 7/8] fs: fix or note I_DIRTY handling bugs in filesystems Nick Piggin
2010-12-29 15:01   ` Christoph Hellwig
2011-01-03 15:03     ` Steven Whitehouse
2011-01-03 16:58       ` Christoph Hellwig
2011-01-04  7:12         ` Nick Piggin
2011-01-04 14:22         ` Steven Whitehouse
2011-01-04  6:04     ` Nick Piggin
2011-01-04  6:39       ` Christoph Hellwig
2011-01-04  7:52         ` Nick Piggin
2011-01-04  9:13           ` Christoph Hellwig
2011-01-04  9:28             ` Nick Piggin
2010-12-18  1:46 ` [patch 8/8] fs: add i_op->sync_inode Nick Piggin
2010-12-29 15:12   ` Christoph Hellwig
2011-01-04  6:27     ` Nick Piggin
2011-01-04  6:57       ` Christoph Hellwig
2011-01-04  8:03         ` Nick Piggin
2011-01-04  8:31           ` Nick Piggin
2011-01-04  9:25             ` Christoph Hellwig
2011-01-04  9:52               ` Nick Piggin
2011-01-06 20:49                 ` Christoph Hellwig
2011-01-07  4:48                   ` Nick Piggin
2011-01-07  7:25                     ` Christoph Hellwig
2011-01-11  3:44                       ` Nick Piggin
2011-01-04  9:25           ` Christoph Hellwig
2011-01-04  9:49             ` Nick Piggin
2011-01-06 20:45               ` Christoph Hellwig
2011-01-07  4:47                 ` Nick Piggin
2011-01-07  7:24                   ` Christoph Hellwig
2011-01-07  7:29                     ` Christoph Hellwig [this message]
2011-01-07 13:10                       ` Christoph Hellwig
2011-01-07 18:30                       ` Ted Ts'o
2011-01-07 18:32                         ` Christoph Hellwig
2011-01-07 19:06   ` Ted Ts'o

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