Btrfs: Leaf reference cache update

This changes the reference cache to make a single cache per root
instead of one cache per transaction, and to key by the byte number
of the disk block instead of the keys inside.

This makes it much less likely to have cache misses if a snapshot
or something has an extra reference on a higher node or a leaf while
the first transaction that added the leaf into the cache is dropping.

Some throttling is added to functions that free blocks heavily so they
wait for old transactions to drop.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 4f0e1d06c384..eccdf13a95ac 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -40,6 +40,7 @@
 #include "print-tree.h"
 #include "async-thread.h"
 #include "locking.h"
+#include "ref-cache.h"
 
 #if 0
 static int check_tree_block(struct btrfs_root *root, struct extent_buffer *buf)
@@ -737,6 +738,10 @@ static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
         spin_lock_init(&root->node_lock);
         spin_lock_init(&root->orphan_lock);
         mutex_init(&root->objectid_mutex);
+
+        btrfs_leaf_ref_tree_init(&root->ref_tree_struct);
+        root->ref_tree = &root->ref_tree_struct;
+
         memset(&root->root_key, 0, sizeof(root->root_key));
         memset(&root->root_item, 0, sizeof(root->root_item));
         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
@@ -1176,9 +1181,6 @@ static int transaction_kthread(void *arg)
                         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);