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/disk-io.c b/fs/btrfs/disk-io.c
index d609239..4f0e1d0 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -716,6 +716,7 @@
root->node = NULL;
root->inode = NULL;
root->commit_root = NULL;
+ root->ref_tree = NULL;
root->sectorsize = sectorsize;
root->nodesize = nodesize;
root->leafsize = leafsize;
@@ -1165,12 +1166,19 @@
vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
mutex_lock(&root->fs_info->transaction_kthread_mutex);
+ printk("btrfs: total reference cache size %Lu\n",
+ root->fs_info->total_ref_cache_size);
+
mutex_lock(&root->fs_info->trans_mutex);
cur = root->fs_info->running_transaction;
if (!cur) {
mutex_unlock(&root->fs_info->trans_mutex);
goto sleep;
}
+
+ printk("btrfs: running reference cache size %Lu\n",
+ root->fs_info->running_ref_cache_size);
+
now = get_seconds();
if (now < cur->start_time || now - cur->start_time < 30) {
mutex_unlock(&root->fs_info->trans_mutex);
@@ -1233,6 +1241,7 @@
spin_lock_init(&fs_info->hash_lock);
spin_lock_init(&fs_info->delalloc_lock);
spin_lock_init(&fs_info->new_trans_lock);
+ spin_lock_init(&fs_info->ref_cache_lock);
init_completion(&fs_info->kobj_unregister);
fs_info->tree_root = tree_root;
@@ -1699,6 +1708,11 @@
printk("btrfs: at unmount delalloc count %Lu\n",
fs_info->delalloc_bytes);
}
+ if (fs_info->total_ref_cache_size) {
+ printk("btrfs: at umount reference cache size %Lu\n",
+ fs_info->total_ref_cache_size);
+ }
+
if (fs_info->extent_root->node)
free_extent_buffer(fs_info->extent_root->node);