From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <46807B32.6050302@yahoo.com.au> Date: Tue, 26 Jun 2007 12:34:26 +1000 From: Nick Piggin MIME-Version: 1.0 Subject: Re: [patch 1/3] add the fsblock layer References: <20070624014528.GA17609@wotan.suse.de> <20070624014613.GB17609@wotan.suse.de> <18046.63436.472085.535177@notabene.brown> <467F71C6.6040204@yahoo.com.au> <20070625122906.GB12446@think.oraclecorp.com> In-Reply-To: <20070625122906.GB12446@think.oraclecorp.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Chris Mason Cc: Neil Brown , Nick Piggin , Linux Kernel Mailing List , Linux Memory Management List , linux-fsdevel@vger.kernel.org List-ID: Chris Mason wrote: > On Mon, Jun 25, 2007 at 05:41:58PM +1000, Nick Piggin wrote: > >>Neil Brown wrote: >>>Why do you think you need PG_blocks? >> >>Block device pagecache (buffer cache) has to be able to accept >>attachment of either buffers or blocks for filesystem metadata, >>and call into either buffer.c or fsblock.c based on that. >> >>If the page flag is really important, we can do some awful hack >>like assuming the first long of the private data is flags, and >>those flags will tell us whether the structure is a buffer_head >>or fsblock ;) But for now it is just easier to use a page flag. > > > The block device pagecache isn't special, and certainly isn't that much > code. I would suggest keeping it buffer head specific and making a > second variant that does only fsblocks. This is mostly to keep the > semantics of PagePrivate sane, lets not fuzz the line. That would require a new inode and address_space for the fsblock type blockdev pagecache, wouldn't it? I just can't think of a better non-intrusive way of allowing a buffer_head filesystem and an fsblock filesystem to live on the same blkdev together. -- SUSE Labs, Novell Inc. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org