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Commit 34cc1781 authored by Steven Whitehouse's avatar Steven Whitehouse
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GFS2: Clean up log flush header writing 



We already send both a pre and post flush to the block device
when writing a journal header. There is no need to wait for
the previous I/O specifically when we do this, unless we've
turned "barriers" off.

As a side effect, this also cleans up the code path for flushing
the journal and makes it more readable.

Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
parent 75ca61c1

fs/gfs2/log.c

+66 −65
Original line number Original line Diff line number Diff line
@@ -491,66 +491,8 @@ static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail) 
	sdp->sd_log_tail = new_tail;

	sdp->sd_log_tail = new_tail;

}

}





/**

 * log_write_header - Get and initialize a journal header buffer

 * @sdp: The GFS2 superblock

 *

 * Returns: the initialized log buffer descriptor

 */





static void log_write_header(struct gfs2_sbd *sdp, u32 flags, int pull)

static void log_flush_wait(struct gfs2_sbd *sdp)

{

	u64 blkno = gfs2_log_bmap(sdp, sdp->sd_log_flush_head);

	struct buffer_head *bh;

	struct gfs2_log_header *lh;

	unsigned int tail;

	u32 hash;



	bh = sb_getblk(sdp->sd_vfs, blkno);

	lock_buffer(bh);

	memset(bh->b_data, 0, bh->b_size);

	set_buffer_uptodate(bh);

	clear_buffer_dirty(bh);



	gfs2_ail1_empty(sdp);

	tail = current_tail(sdp);



	lh = (struct gfs2_log_header *)bh->b_data;

	memset(lh, 0, sizeof(struct gfs2_log_header));

	lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC);

	lh->lh_header.mh_type = cpu_to_be32(GFS2_METATYPE_LH);

	lh->lh_header.__pad0 = cpu_to_be64(0);

	lh->lh_header.mh_format = cpu_to_be32(GFS2_FORMAT_LH);

	lh->lh_header.mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);

	lh->lh_sequence = cpu_to_be64(sdp->sd_log_sequence++);

	lh->lh_flags = cpu_to_be32(flags);

	lh->lh_tail = cpu_to_be32(tail);

	lh->lh_blkno = cpu_to_be32(sdp->sd_log_flush_head);

	hash = gfs2_disk_hash(bh->b_data, sizeof(struct gfs2_log_header));

	lh->lh_hash = cpu_to_be32(hash);



	bh->b_end_io = end_buffer_write_sync;

	get_bh(bh);

	if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags))

		submit_bh(WRITE_SYNC | REQ_META | REQ_PRIO, bh);

	else

		submit_bh(WRITE_FLUSH_FUA | REQ_META, bh);

	wait_on_buffer(bh);



	if (!buffer_uptodate(bh))

		gfs2_io_error_bh(sdp, bh);

	brelse(bh);



	if (sdp->sd_log_tail != tail)

		log_pull_tail(sdp, tail);

	else

		gfs2_assert_withdraw(sdp, !pull);



	sdp->sd_log_idle = (tail == sdp->sd_log_flush_head);

	gfs2_log_incr_head(sdp);

}



static void log_flush_commit(struct gfs2_sbd *sdp)

{

{

	DEFINE_WAIT(wait);

	DEFINE_WAIT(wait);
@@ -563,8 +505,6 @@ static void log_flush_commit(struct gfs2_sbd *sdp) 
		} while(atomic_read(&sdp->sd_log_in_flight));

		} while(atomic_read(&sdp->sd_log_in_flight));

		finish_wait(&sdp->sd_log_flush_wait, &wait);

		finish_wait(&sdp->sd_log_flush_wait, &wait);

	}

	}



	log_write_header(sdp, 0, 0);

}

}





static int bd_cmp(void *priv, struct list_head *a, struct list_head *b)

static int bd_cmp(void *priv, struct list_head *a, struct list_head *b)
@@ -633,6 +573,68 @@ static void gfs2_ordered_wait(struct gfs2_sbd *sdp) 
	gfs2_log_unlock(sdp);

	gfs2_log_unlock(sdp);

}

}





/**

 * log_write_header - Get and initialize a journal header buffer

 * @sdp: The GFS2 superblock

 *

 * Returns: the initialized log buffer descriptor

 */



static void log_write_header(struct gfs2_sbd *sdp, u32 flags, int pull)

{

	u64 blkno = gfs2_log_bmap(sdp, sdp->sd_log_flush_head);

	struct buffer_head *bh;

	struct gfs2_log_header *lh;

	unsigned int tail;

	u32 hash;



	bh = sb_getblk(sdp->sd_vfs, blkno);

	lock_buffer(bh);

	memset(bh->b_data, 0, bh->b_size);

	set_buffer_uptodate(bh);

	clear_buffer_dirty(bh);



	gfs2_ail1_empty(sdp);

	tail = current_tail(sdp);



	lh = (struct gfs2_log_header *)bh->b_data;

	memset(lh, 0, sizeof(struct gfs2_log_header));

	lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC);

	lh->lh_header.mh_type = cpu_to_be32(GFS2_METATYPE_LH);

	lh->lh_header.__pad0 = cpu_to_be64(0);

	lh->lh_header.mh_format = cpu_to_be32(GFS2_FORMAT_LH);

	lh->lh_header.mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);

	lh->lh_sequence = cpu_to_be64(sdp->sd_log_sequence++);

	lh->lh_flags = cpu_to_be32(flags);

	lh->lh_tail = cpu_to_be32(tail);

	lh->lh_blkno = cpu_to_be32(sdp->sd_log_flush_head);

	hash = gfs2_disk_hash(bh->b_data, sizeof(struct gfs2_log_header));

	lh->lh_hash = cpu_to_be32(hash);



	bh->b_end_io = end_buffer_write_sync;

	get_bh(bh);

	if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags)) {

		gfs2_ordered_wait(sdp);

		log_flush_wait(sdp);

		submit_bh(WRITE_SYNC | REQ_META | REQ_PRIO, bh);

	} else {

		submit_bh(WRITE_FLUSH_FUA | REQ_META, bh);

	}

	wait_on_buffer(bh);



	if (!buffer_uptodate(bh))

		gfs2_io_error_bh(sdp, bh);

	brelse(bh);



	if (sdp->sd_log_tail != tail)

		log_pull_tail(sdp, tail);

	else

		gfs2_assert_withdraw(sdp, !pull);



	sdp->sd_log_idle = (tail == sdp->sd_log_flush_head);

	gfs2_log_incr_head(sdp);

}



/**

/**

 * gfs2_log_flush - flush incore transaction(s)

 * gfs2_log_flush - flush incore transaction(s)

 * @sdp: the filesystem

 * @sdp: the filesystem
@@ -676,11 +678,10 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl) 




	gfs2_ordered_write(sdp);

	gfs2_ordered_write(sdp);

	lops_before_commit(sdp);

	lops_before_commit(sdp);

	gfs2_ordered_wait(sdp);





	if (sdp->sd_log_head != sdp->sd_log_flush_head)

	if (sdp->sd_log_head != sdp->sd_log_flush_head) {

		log_flush_commit(sdp);

		log_write_header(sdp, 0, 0);

	else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle){

	} else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle){

		gfs2_log_lock(sdp);

		gfs2_log_lock(sdp);

		atomic_dec(&sdp->sd_log_blks_free); /* Adjust for unreserved buffer */

		atomic_dec(&sdp->sd_log_blks_free); /* Adjust for unreserved buffer */

		trace_gfs2_log_blocks(sdp, -1);

		trace_gfs2_log_blocks(sdp, -1);