Commit 34901f70 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Writeback optimisation 



Schedule writes using WB_SYNC_NONE first, then come back for a second pass
using WB_SYNC_ALL.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent ed90ef51

fs/nfs/write.c

+22 −10
Original line number Diff line number Diff line
@@ -1325,27 +1325,39 @@ long nfs_sync_mapping_wait(struct address_space *mapping, struct writeback_contr 
	return ret;

}



static int __nfs_write_mapping(struct address_space *mapping, struct writeback_control *wbc, int how)

{

	int ret;



	ret = nfs_writepages(mapping, wbc);

	if (ret < 0)

		goto out;

	ret = nfs_sync_mapping_wait(mapping, wbc, how);

	if (ret < 0)

		goto out;

	return 0;

out:

	__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);

	return ret;

}



/* Two pass sync: first using WB_SYNC_NONE, then WB_SYNC_ALL */

static int nfs_write_mapping(struct address_space *mapping, int how)

{

	struct writeback_control wbc = {

		.bdi = mapping->backing_dev_info,

		.sync_mode = WB_SYNC_ALL,

		.sync_mode = WB_SYNC_NONE,

		.nr_to_write = LONG_MAX,

		.for_writepages = 1,

		.range_cyclic = 1,

	};

	int ret;



	ret = nfs_writepages(mapping, &wbc);

	if (ret < 0)

		goto out;

	ret = nfs_sync_mapping_wait(mapping, &wbc, how);

	ret = __nfs_write_mapping(mapping, &wbc, how);

	if (ret < 0)

		goto out;

	return 0;

out:

	__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);

		return ret;

	wbc.sync_mode = WB_SYNC_ALL;

	return __nfs_write_mapping(mapping, &wbc, how);

}



/*