nilfs2: add read ahead mode to nilfs_btnode_submit_block

This adds mode argument to nilfs_btnode_submit_block() function and
allows it to issue a read-ahead request.

An optional submit_ptr argument is also added to store the actual
block address for which bio is sent.  submit_ptr is used for a series
of read-ahead requests, and helps to decide if each requested block is
continous to the previous one on disk.

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

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c
index 6462c7026479..4669389bf686 100644
--- a/fs/nilfs2/btree.c
+++ b/fs/nilfs2/btree.c
@@ -71,9 +71,10 @@ static int nilfs_btree_get_block(const struct nilfs_bmap *btree, __u64 ptr,
 {
         struct address_space *btnc = &NILFS_BMAP_I(btree)->i_btnode_cache;
         struct buffer_head *bh;
+        sector_t pbn = 0;
         int err;
 
-        err = nilfs_btnode_submit_block(btnc, ptr, 0, bhp);
+        err = nilfs_btnode_submit_block(btnc, ptr, pbn, READ, bhp, &pbn);
         if (err)
                 return err == -EEXIST ? 0 : err;