From: Ted Ts'o <tytso@mit.edu>
To: Saugata Das <saugata.das@stericsson.com>
Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
saugata.das@linaro.org, arnd.bergmann@linaro.org,
adilger@whamcloud.com
Subject: Re: [PATCH] REQ_META set during meta data write
Date: Thu, 1 Mar 2012 13:33:27 -0500 [thread overview]
Message-ID: <20120301183327.GA32588@thunk.org> (raw)
In-Reply-To: <1330625463-5683-1-git-send-email-saugata.das@stericsson.com>
On Thu, Mar 01, 2012 at 11:41:03PM +0530, Saugata Das wrote:
> From: Saugata Das <saugata.das@linaro.org>
>
> Today, storage devices like eMMC has special features like data tagging
> (introduced in MMC-4.5 version) in order to improve performance of some
> specific writes. On MMC stack, data tagging is used for all writes which has
> REQ_META flag set. On EXT4, however, currently REQ_META is set only for read.
> This patch adds the capability to add REQ_META flag during meta data write.
> This patch adds new function set_buffer_meta, which is used to set a bit
> BH_Meta in the b_state field when meta data and super block is made dirty.
>
> --- a/fs/buffer.c
> +++ b/fs/buffer.c
> @@ -2926,6 +2926,9 @@ int submit_bh(int rw, struct buffer_head * bh)
> if (test_set_buffer_req(bh) && (rw & WRITE))
> clear_buffer_write_io_error(bh);
>
> + if (buffer_meta(bh) && (rw & WRITE))
> + rw |= REQ_META;
> +
I know it's not necessary for your purposes as stated in the commit
description, but wouldn't it be better if buffer_meta() always caused
REQ_META to be set, regardless of whether we are doing a read or a
write?
- Ted
next prev parent reply other threads:[~2012-03-01 18:33 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-01 18:11 [PATCH] REQ_META set during meta data write Saugata Das
2012-03-01 18:33 ` Ted Ts'o [this message]
2012-03-01 20:04 ` Saugata Das
2012-03-01 20:21 ` Eric Sandeen
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