Btrfs: Add a leaf reference cache
Much of the IO done while dropping snapshots is done looking up
leaves in the filesystem trees to see if they point to any extents and
to drop the references on any extents found.
This creates a cache so that IO isn't required.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 768b0d2..543e5ee 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -24,6 +24,7 @@
#include "disk-io.h"
#include "transaction.h"
#include "locking.h"
+#include "ref-cache.h"
static int total_trans = 0;
extern struct kmem_cache *btrfs_trans_handle_cachep;
@@ -31,6 +32,13 @@
#define BTRFS_ROOT_TRANS_TAG 0
+struct dirty_root {
+ struct list_head list;
+ struct btrfs_root *root;
+ struct btrfs_root *latest_root;
+ struct btrfs_leaf_ref_tree ref_tree;
+};
+
static noinline void put_transaction(struct btrfs_transaction *transaction)
{
WARN_ON(transaction->use_count == 0);
@@ -84,6 +92,7 @@
static noinline int record_root_in_trans(struct btrfs_root *root)
{
+ struct dirty_root *dirty;
u64 running_trans_id = root->fs_info->running_transaction->transid;
if (root->ref_cows && root->last_trans < running_trans_id) {
WARN_ON(root == root->fs_info->extent_root);
@@ -91,7 +100,25 @@
radix_tree_tag_set(&root->fs_info->fs_roots_radix,
(unsigned long)root->root_key.objectid,
BTRFS_ROOT_TRANS_TAG);
+
+ dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
+ BUG_ON(!dirty);
+ dirty->root = kmalloc(sizeof(*dirty->root), GFP_NOFS);
+ BUG_ON(!dirty->root);
+
+ dirty->latest_root = root;
+ INIT_LIST_HEAD(&dirty->list);
+ btrfs_leaf_ref_tree_init(&dirty->ref_tree);
+ dirty->ref_tree.generation = running_trans_id;
+
root->commit_root = btrfs_root_node(root);
+ root->ref_tree = &dirty->ref_tree;
+
+ memcpy(dirty->root, root, sizeof(*root));
+ spin_lock_init(&dirty->root->node_lock);
+ mutex_init(&dirty->root->objectid_mutex);
+ dirty->root->node = root->commit_root;
+ dirty->root->commit_root = NULL;
} else {
WARN_ON(1);
}
@@ -310,12 +337,6 @@
return 0;
}
-struct dirty_root {
- struct list_head list;
- struct btrfs_root *root;
- struct btrfs_root *latest_root;
-};
-
int btrfs_add_dead_root(struct btrfs_root *root,
struct btrfs_root *latest,
struct list_head *dead_list)
@@ -325,8 +346,10 @@
dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
if (!dirty)
return -ENOMEM;
+ btrfs_leaf_ref_tree_init(&dirty->ref_tree);
dirty->root = root;
dirty->latest_root = latest;
+ root->ref_tree = NULL;
list_add(&dirty->list, dead_list);
return 0;
}
@@ -354,11 +377,23 @@
radix_tree_tag_clear(radix,
(unsigned long)root->root_key.objectid,
BTRFS_ROOT_TRANS_TAG);
+
+ BUG_ON(!root->ref_tree);
+ dirty = container_of(root->ref_tree, struct dirty_root,
+ ref_tree);
+
if (root->commit_root == root->node) {
WARN_ON(root->node->start !=
btrfs_root_bytenr(&root->root_item));
+
+ BUG_ON(!btrfs_leaf_ref_tree_empty(
+ root->ref_tree));
free_extent_buffer(root->commit_root);
root->commit_root = NULL;
+ root->ref_tree = NULL;
+
+ kfree(dirty->root);
+ kfree(dirty);
/* make sure to update the root on disk
* so we get any updates to the block used
@@ -370,23 +405,12 @@
&root->root_item);
continue;
}
- dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
- BUG_ON(!dirty);
- dirty->root = kmalloc(sizeof(*dirty->root), GFP_NOFS);
- BUG_ON(!dirty->root);
memset(&root->root_item.drop_progress, 0,
sizeof(struct btrfs_disk_key));
root->root_item.drop_level = 0;
-
- memcpy(dirty->root, root, sizeof(*root));
- dirty->root->node = root->commit_root;
- dirty->latest_root = root;
- spin_lock_init(&dirty->root->node_lock);
- mutex_init(&dirty->root->objectid_mutex);
-
root->commit_root = NULL;
-
+ root->ref_tree = NULL;
root->root_key.offset = root->fs_info->generation;
btrfs_set_root_bytenr(&root->root_item,
root->node->start);
@@ -409,6 +433,7 @@
list_add(&dirty->list, list);
} else {
WARN_ON(1);
+ free_extent_buffer(dirty->root->node);
kfree(dirty->root);
kfree(dirty);
}
@@ -514,6 +539,8 @@
ret = btrfs_end_transaction(trans, tree_root);
BUG_ON(ret);
+ btrfs_remove_leaf_refs(dirty->root);
+
free_extent_buffer(dirty->root->node);
kfree(dirty->root);
kfree(dirty);
@@ -698,6 +725,10 @@
&dirty_fs_roots);
BUG_ON(ret);
+ spin_lock(&root->fs_info->ref_cache_lock);
+ root->fs_info->running_ref_cache_size = 0;
+ spin_unlock(&root->fs_info->ref_cache_lock);
+
ret = btrfs_commit_tree_roots(trans, root);
BUG_ON(ret);