Btrfs: very simple readdir readahead
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index f96bd92..e76fcd8 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -332,6 +332,34 @@
return d_splice_alias(inode, dentry);
}
+static void reada_leaves(struct btrfs_root *root, struct btrfs_path *path)
+{
+ struct buffer_head *bh;
+ struct btrfs_node *node;
+ int i;
+ int nritems;
+ u64 objectid;
+ u64 item_objectid;
+ u64 blocknr;
+ int slot;
+
+ if (!path->nodes[1])
+ return;
+ node = btrfs_buffer_node(path->nodes[1]);
+ slot = path->slots[1];
+ objectid = btrfs_disk_key_objectid(&node->ptrs[slot].key);
+ nritems = btrfs_header_nritems(&node->header);
+ for (i = slot; i < nritems; i++) {
+ item_objectid = btrfs_disk_key_objectid(&node->ptrs[i].key);
+ if (item_objectid != objectid)
+ break;
+ blocknr = btrfs_node_blockptr(node, i);
+ bh = sb_getblk(root->fs_info->sb, blocknr);
+ ll_rw_block(READ, 1, &bh);
+ brelse(bh);
+ }
+
+}
static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
struct inode *inode = filp->f_path.dentry->d_inode;
@@ -358,6 +386,7 @@
goto err;
}
advance = 0;
+ reada_leaves(root, &path);
while(1) {
leaf = btrfs_buffer_leaf(path.nodes[0]);
nritems = btrfs_header_nritems(&leaf->header);
@@ -370,13 +399,8 @@
leaf = btrfs_buffer_leaf(path.nodes[0]);
nritems = btrfs_header_nritems(&leaf->header);
slot = path.slots[0];
-#if 0
- page_cache_readahead(
- inode->i_sb->s_bdev->bd_inode->i_mapping,
- &filp->f_ra, filp,
- path.nodes[0]->b_blocknr >>
- (PAGE_CACHE_SHIFT - inode->i_blkbits), 1);
-#endif
+ if (path.nodes[1] && path.slots[1] == 0)
+ reada_leaves(root, &path);
} else {
slot++;
path.slots[0]++;