Date: Mon, 30 Mar 2009 13:59:28 -0700
From: Brad Boyer <flar@allandria.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: linux-fsdevel@vger.kernel.org, jens.axboe@oracle.com,
       linux-kernel@vger.kernel.org
Subject: Re: [patch 3/3] splice: implement default splice_read method
Message-ID: <20090330205927.GA7707@cynthia.pants.nu>
References: <E1LoNev-0007kP-U7@pomaz-ex.szeredi.hu> <E1LoNie-0007m5-B4@pomaz-ex.szeredi.hu>
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On Mon, Mar 30, 2009 at 10:04:28PM +0200, Miklos Szeredi wrote:
> From: Miklos Szeredi <mszeredi@suse.cz>
> 
> If f_op->splice_read() is not implemented fall back to a plain read.
> Use vfs_readv() to read into previously allocated pages.
> 
> This will allow splice and functions using splice, such as the loop
> device, to work on all filesystems.  This includes "direct_io" files
> in fuse which bypass the page cache.

Based on your description, I would have expected this patch to make
the loop driver work seamlessly. Unless I'm misreading something, I
think the loop driver will still error out if the fs driver in question
doesn't explicitly set splice_read.o

>From drivers/block/loop.c:
724         /* new backing store needs to support loop (eg splice_read) */
725         if (!inode->i_fop->splice_read)
726                 goto out_putf;
727 

Did you accidentally leave out some changes? Please let me know if I
am missing something obvious.

	Brad Boyer
	flar@allandria.com

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