From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Sandeen Subject: Re: [PATCH] REQ_META set during meta data write Date: Thu, 01 Mar 2012 14:21:12 -0600 Message-ID: <4F4FDA38.6060601@redhat.com> References: <1330625463-5683-1-git-send-email-saugata.das@stericsson.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, saugata.das@linaro.org, arnd.bergmann@linaro.org, tytso@mit.edu, adilger@whamcloud.com To: Saugata Das Return-path: Received: from mx1.redhat.com ([209.132.183.28]:28033 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754882Ab2CAUVV (ORCPT ); Thu, 1 Mar 2012 15:21:21 -0500 In-Reply-To: <1330625463-5683-1-git-send-email-saugata.das@stericsson.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 3/1/12 12:11 PM, Saugata Das wrote: > From: Saugata Das > > 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. > > Signed-off-by: Saugata Das > Acked-by: Arnd Bergmann I like this idea too, partly because I've had a project in the back of my mind to teach seekwatcher to optionally distinguish between metadata & data IO on its charts, but I had noticed that ext4 didn't always tag things. -Eric > --- > fs/buffer.c | 3 +++ > fs/ext4/ext4_jbd2.c | 4 ++++ > fs/ext4/inode.c | 4 +++- > include/linux/buffer_head.h | 2 ++ > 4 files changed, 12 insertions(+), 1 deletions(-) > > diff --git a/fs/buffer.c b/fs/buffer.c > index 19d8eb7..71c8c74 100644 > --- 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; > + > /* > * from here on down, it's all bio -- do the initial mapping, > * submit_bio -> generic_make_request may further map this bio around > diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c > index aca1790..097c062 100644 > --- a/fs/ext4/ext4_jbd2.c > +++ b/fs/ext4/ext4_jbd2.c > @@ -107,6 +107,8 @@ int __ext4_handle_dirty_metadata(const char *where, unsigned int line, > { > int err = 0; > > + set_buffer_meta(bh); > + > if (ext4_handle_valid(handle)) { > err = jbd2_journal_dirty_metadata(handle, bh); > if (err) { > @@ -143,6 +145,8 @@ int __ext4_handle_dirty_super(const char *where, unsigned int line, > struct buffer_head *bh = EXT4_SB(sb)->s_sbh; > int err = 0; > > + set_buffer_meta(bh); > + > if (ext4_handle_valid(handle)) { > err = jbd2_journal_dirty_metadata(handle, bh); > if (err) > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 92655fd..105e1d0 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -4144,8 +4144,10 @@ int ext4_write_inode(struct inode *inode, struct writeback_control *wbc) > err = __ext4_get_inode_loc(inode, &iloc, 0); > if (err) > return err; > - if (wbc->sync_mode == WB_SYNC_ALL) > + if (wbc->sync_mode == WB_SYNC_ALL) { > + set_buffer_meta(iloc.bh); > sync_dirty_buffer(iloc.bh); > + } > if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) { > EXT4_ERROR_INODE_BLOCK(inode, iloc.bh->b_blocknr, > "IO error syncing inode"); > diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h > index 458f497..13bba17 100644 > --- a/include/linux/buffer_head.h > +++ b/include/linux/buffer_head.h > @@ -34,6 +34,7 @@ enum bh_state_bits { > BH_Write_EIO, /* I/O error on write */ > BH_Unwritten, /* Buffer is allocated on disk but not written */ > BH_Quiet, /* Buffer Error Prinks to be quiet */ > + BH_Meta, /* Is meta */ > > BH_PrivateStart,/* not a state bit, but the first bit available > * for private allocation by other entities > @@ -124,6 +125,7 @@ BUFFER_FNS(Delay, delay) > BUFFER_FNS(Boundary, boundary) > BUFFER_FNS(Write_EIO, write_io_error) > BUFFER_FNS(Unwritten, unwritten) > +BUFFER_FNS(Meta, meta) > > #define bh_offset(bh) ((unsigned long)(bh)->b_data & ~PAGE_MASK) > #define touch_buffer(bh) mark_page_accessed(bh->b_page)