nilfs2: enable sync_page method

This adds a missing sync_page method which unplugs bio requests when
waiting for page locks. This will improve read performance of nilfs.

Here is a measurement result using dd command.

Without this patch:

 # mount -t nilfs2 /dev/sde1 /test
 # dd if=/test/aaa of=/dev/null bs=512k
 1024+0 records in
 1024+0 records out
 536870912 bytes (537 MB) copied, 6.00688 seconds, 89.4 MB/s

With this patch:

 # mount -t nilfs2 /dev/sde1 /test
 # dd if=/test/aaa of=/dev/null bs=512k
 1024+0 records in
 1024+0 records out
 536870912 bytes (537 MB) copied, 3.54998 seconds, 151 MB/s

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

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index 3f70eedc0de8..f25fd4b895bc 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -240,7 +240,7 @@ nilfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
 struct address_space_operations nilfs_aops = {
         .writepage              = nilfs_writepage,
         .readpage               = nilfs_readpage,
-        /* .sync_page           = nilfs_sync_page, */
+        .sync_page              = block_sync_page,
         .writepages             = nilfs_writepages,
         .set_page_dirty         = nilfs_set_page_dirty,
         .readpages              = nilfs_readpages,