Commit df308bcf authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Alex Elder
Browse files

xfs: remove periodic superblock writeback 



All modifications to the superblock are done transactional through
xfs_trans_log_buf, so there is no reason to initiate periodic
asynchronous writeback.  This only removes the superblock from the
delwri list and will lead to sub-optimal I/O scheduling.

Cut down xfs_sync_fsdata now that it's only used for synchronous
superblock writes and move the log coverage checks into the two
callers.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAlex Elder <aelder@sgi.com>
parent f9837107

fs/xfs/linux-2.6/xfs_sync.c

+27 −63
Original line number Diff line number Diff line
@@ -356,68 +356,24 @@ xfs_commit_dummy_trans( 


STATIC int

xfs_sync_fsdata(

	struct xfs_mount	*mp,

	int			flags)

	struct xfs_mount	*mp)

{

	struct xfs_buf		*bp;

	struct xfs_buf_log_item	*bip;

	int			error = 0;



	/*

	 * If this is xfssyncd() then only sync the superblock if we can

	 * lock it without sleeping and it is not pinned.

	 */

	if (flags & SYNC_TRYLOCK) {

		ASSERT(!(flags & SYNC_WAIT));



		bp = xfs_getsb(mp, XBF_TRYLOCK);

		if (!bp)

			goto out;



		bip = XFS_BUF_FSPRIVATE(bp, struct xfs_buf_log_item *);

		if (!bip || !xfs_buf_item_dirty(bip) || XFS_BUF_ISPINNED(bp))

			goto out_brelse;

	} else {

		bp = xfs_getsb(mp, 0);



		/*

		 * If the buffer is pinned then push on the log so we won't

		 * get stuck waiting in the write for someone, maybe

		 * ourselves, to flush the log.

	 * If the buffer is pinned then push on the log so we won't get stuck

	 * waiting in the write for someone, maybe ourselves, to flush the log.

	 *

		 * Even though we just pushed the log above, we did not have

		 * the superblock buffer locked at that point so it can

		 * become pinned in between there and here.

	 * Even though we just pushed the log above, we did not have the

	 * superblock buffer locked at that point so it can become pinned in

	 * between there and here.

	 */

	bp = xfs_getsb(mp, 0);

	if (XFS_BUF_ISPINNED(bp))

		xfs_log_force(mp, 0);

	}





	if (flags & SYNC_WAIT)

	XFS_BUF_UNASYNC(bp);

	else

		XFS_BUF_ASYNC(bp);



	error = xfs_bwrite(mp, bp);

	if (error)

		return error;



	/*

	 * If this is a data integrity sync make sure all pending buffers

	 * are flushed out for the log coverage check below.

	 */

	if (flags & SYNC_WAIT)

		xfs_flush_buftarg(mp->m_ddev_targp, 1);



	if (xfs_log_need_covered(mp))

		error = xfs_commit_dummy_trans(mp, flags);

	return error;



 out_brelse:

	xfs_buf_relse(bp);

 out:

	return error;

	return xfs_bwrite(mp, bp);

}



/*
@@ -441,7 +397,7 @@ int 
xfs_quiesce_data(

	struct xfs_mount	*mp)

{

	int error;

	int			error, error2 = 0;



	/* push non-blocking */

	xfs_sync_data(mp, 0);
@@ -452,13 +408,20 @@ xfs_quiesce_data( 
	xfs_qm_sync(mp, SYNC_WAIT);



	/* write superblock and hoover up shutdown errors */

	error = xfs_sync_fsdata(mp, SYNC_WAIT);

	error = xfs_sync_fsdata(mp);



	/* make sure all delwri buffers are written out */

	xfs_flush_buftarg(mp->m_ddev_targp, 1);



	/* mark the log as covered if needed */

	if (xfs_log_need_covered(mp))

		error2 = xfs_commit_dummy_trans(mp, SYNC_WAIT);



	/* flush data-only devices */

	if (mp->m_rtdev_targp)

		XFS_bflush(mp->m_rtdev_targp);



	return error;

	return error ? error : error2;

}



STATIC void
@@ -581,9 +544,9 @@ xfs_flush_inodes( 
}



/*

 * Every sync period we need to unpin all items, reclaim inodes, sync

 * quota and write out the superblock. We might need to cover the log

 * to indicate it is idle.

 * Every sync period we need to unpin all items, reclaim inodes and sync

 * disk quotas.  We might need to cover the log to indicate that the

 * filesystem is idle.

 */

STATIC void

xfs_sync_worker(
@@ -597,7 +560,8 @@ xfs_sync_worker( 
		xfs_reclaim_inodes(mp, 0);

		/* dgc: errors ignored here */

		error = xfs_qm_sync(mp, SYNC_TRYLOCK);

		error = xfs_sync_fsdata(mp, SYNC_TRYLOCK);

		if (xfs_log_need_covered(mp))

			error = xfs_commit_dummy_trans(mp, 0);

	}

	mp->m_sync_seq++;

	wake_up(&mp->m_wait_single_sync_task);