Btrfs: directory readahead
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index e1b6e13..354524a 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -5,6 +5,7 @@
#include <linux/scatterlist.h>
#include <linux/swap.h>
#include <linux/radix-tree.h>
+#include <linux/file.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
@@ -253,6 +254,29 @@
.sync_page = block_sync_page,
};
+int readahead_tree_block(struct btrfs_root *root, u64 blocknr)
+{
+ struct buffer_head *bh = NULL;
+
+ bh = btrfs_find_create_tree_block(root, blocknr);
+ if (!bh)
+ return 0;
+ if (buffer_uptodate(bh))
+ goto done;
+ if (test_set_buffer_locked(bh))
+ goto done;
+ if (!buffer_uptodate(bh)) {
+ get_bh(bh);
+ bh->b_end_io = end_buffer_read_sync;
+ submit_bh(READ, bh);
+ } else {
+ unlock_buffer(bh);
+ }
+done:
+ brelse(bh);
+ return 0;
+}
+
struct buffer_head *read_tree_block(struct btrfs_root *root, u64 blocknr)
{
struct buffer_head *bh = NULL;
@@ -270,11 +294,14 @@
wait_on_buffer(bh);
if (!buffer_uptodate(bh))
goto fail;
- csum_tree_block(root, bh, 1);
} else {
unlock_buffer(bh);
}
uptodate:
+ if (!buffer_checked(bh)) {
+ csum_tree_block(root, bh, 1);
+ set_buffer_checked(bh);
+ }
if (check_tree_block(root, bh))
BUG();
return bh;
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 444ebb0..1ee7d2a 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -5,6 +5,11 @@
#define BTRFS_SUPER_INFO_OFFSET (16 * 1024)
+enum btrfs_bh_state_bits {
+ BH_Checked = BH_PrivateStart,
+};
+BUFFER_FNS(Checked, checked);
+
static inline struct btrfs_node *btrfs_buffer_node(struct buffer_head *bh)
{
return (struct btrfs_node *)bh->b_data;
@@ -21,6 +26,7 @@
}
struct buffer_head *read_tree_block(struct btrfs_root *root, u64 blocknr);
+int readahead_tree_block(struct btrfs_root *root, u64 blocknr);
struct buffer_head *btrfs_find_create_tree_block(struct btrfs_root *root,
u64 blocknr);
int write_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 8b8cbe2..2837fdd 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -812,6 +812,7 @@
BUG_ON(ret);
buf = btrfs_find_create_tree_block(root, ins.objectid);
set_buffer_uptodate(buf);
+ set_buffer_checked(buf);
set_radix_bit(&trans->transaction->dirty_pages, buf->b_page->index);
return buf;
}
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 7ecbe7c..a29a781b 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -585,6 +585,31 @@
return d_splice_alias(inode, dentry);
}
+static void reada_leaves(struct btrfs_root *root, struct btrfs_path *path)
+{
+ 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);
+ readahead_tree_block(root, blocknr);
+ }
+}
+
static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
struct inode *inode = filp->f_path.dentry->d_inode;
@@ -619,6 +644,7 @@
if (ret < 0)
goto err;
advance = 0;
+ reada_leaves(root, path);
while(1) {
leaf = btrfs_buffer_leaf(path->nodes[0]);
nritems = btrfs_header_nritems(&leaf->header);
@@ -631,6 +657,8 @@
leaf = btrfs_buffer_leaf(path->nodes[0]);
nritems = btrfs_header_nritems(&leaf->header);
slot = path->slots[0];
+ if (path->slots[1] == 0)
+ reada_leaves(root, path);
} else {
slot++;
path->slots[0]++;
