nilfs2: get rid of private page allocator

Previously, nilfs was cloning pages for mmapped region to freeze their
data and ensure consistency of checksum during writeback cycles.  A
private page allocator was used for this page cloning.  But, we no
longer need to do that since clear_page_dirty_for_io function sets up
pte so that vm_ops->page_mkwrite function is called right before the
mmapped pages are modified and nilfs_page_mkwrite function can safely
wait for the pages to be written back to disk.

So, this stops making a copy of mmapped pages during writeback, and
eliminates the private page allocation and deallocation functions from
nilfs.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

1 files changed, 0 insertions, 12 deletions

diff --git a/fs/nilfs2/segbuf.c b/fs/nilfs2/segbuf.c
index 2853ff20f85a..410ec2b1af4f 100644
--- a/fs/nilfs2/segbuf.c
+++ b/fs/nilfs2/segbuf.c
@@ -254,18 +254,6 @@ static void nilfs_release_buffers(struct list_head *list)
 
         list_for_each_entry_safe(bh, n, list, b_assoc_buffers) {
                 list_del_init(&bh->b_assoc_buffers);
-                if (buffer_nilfs_allocated(bh)) {
-                        struct page *clone_page = bh->b_page;
-
-                        /* remove clone page */
-                        brelse(bh);
-                        page_cache_release(clone_page); /* for each bh */
-                        if (page_count(clone_page) <= 2) {
-                                lock_page(clone_page);
-                                nilfs_free_private_page(clone_page);
-                        }
-                        continue;
-                }
                 brelse(bh);
         }
 }