[PATCH] Direct Migration V9: Avoid writeback / page_migrate() method

Migrate a page with buffers without requiring writeback

This introduces a new address space operation migratepage() that may be used
by a filesystem to implement its own version of page migration.

A version is provided that migrates buffers attached to pages.  Some
filesystems (ext2, ext3, xfs) are modified to utilize this feature.

The swapper address space operation are modified so that a regular
migrate_page() will occur for anonymous pages without writeback (migrate_pages
forces every anonymous page to have a swap entry).

Signed-off-by: Mike Kravetz <kravetz@us.ibm.com>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 2 insertions, 0 deletions

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index 120626789406..9892268e3005 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -1462,4 +1462,5 @@ struct address_space_operations linvfs_aops = {
         .commit_write           = generic_commit_write,
         .bmap                   = linvfs_bmap,
         .direct_IO              = linvfs_direct_IO,
+        .migratepage            = buffer_migrate_page,
 };
diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index a36a8e3b703f..bfb4f2917bb6 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -1521,6 +1521,7 @@ xfs_mapping_buftarg(
         struct address_space    *mapping;
         static struct address_space_operations mapping_aops = {
                 .sync_page = block_sync_page,
+                .migratepage = fail_migrate_page,
         };
 
         inode = new_inode(bdev->bd_inode->i_sb);