Btrfs: Add per-root block accounting and sysfs entries

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

1 files changed, 33 insertions, 1 deletions

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 18abea802794..2b15daa3a9f2 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -236,6 +236,7 @@ static int wait_for_commit(struct btrfs_root *root,
 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 list_head *dead_list)
@@ -278,6 +279,15 @@ static int add_dirty_roots(struct btrfs_trans_handle *trans,
                                         btrfs_root_blocknr(&root->root_item));
                                 brelse(root->commit_root);
                                 root->commit_root = NULL;
+
+                                /* make sure to update the root on disk
+                                 * so we get any updates to the block used
+                                 * counts
+                                 */
+                                err = btrfs_update_root(trans,
+                                                root->fs_info->tree_root,
+                                                &root->root_key,
+                                                &root->root_item);
                                 continue;
                         }
                         dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
@@ -291,6 +301,7 @@ static int add_dirty_roots(struct btrfs_trans_handle *trans,
 
                         memcpy(dirty->root, root, sizeof(*root));
                         dirty->root->node = root->commit_root;
+                        dirty->latest_root = root;
                         root->commit_root = NULL;
 
                         root->root_key.offset = root->fs_info->generation;
@@ -384,20 +395,29 @@ static int drop_dirty_roots(struct btrfs_root *tree_root,
 {
         struct dirty_root *dirty;
         struct btrfs_trans_handle *trans;
+        u64 num_blocks;
+        u64 blocks_used;
         int ret = 0;
         int err;
 
         while(!list_empty(list)) {
+                struct btrfs_root *root;
+
                 mutex_lock(&tree_root->fs_info->fs_mutex);
                 dirty = list_entry(list->next, struct dirty_root, list);
                 list_del_init(&dirty->list);
 
+                num_blocks = btrfs_root_blocks_used(&dirty->root->root_item);
+                root = dirty->latest_root;
+
                 while(1) {
                         trans = btrfs_start_transaction(tree_root, 1);
+
                         ret = btrfs_drop_snapshot(trans, dirty->root);
                         if (ret != -EAGAIN) {
                                 break;
                         }
+
                         err = btrfs_update_root(trans,
                                         tree_root,
                                         &dirty->root->root_key,
@@ -414,9 +434,19 @@ static int drop_dirty_roots(struct btrfs_root *tree_root,
                         mutex_lock(&tree_root->fs_info->fs_mutex);
                 }
                 BUG_ON(ret);
+
+                num_blocks -= btrfs_root_blocks_used(&dirty->root->root_item);
+                blocks_used = btrfs_root_blocks_used(&root->root_item);
+                if (num_blocks) {
+                        record_root_in_trans(root);
+                        btrfs_set_root_blocks_used(&root->root_item,
+                                                   blocks_used - num_blocks);
+                }
                 ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key);
-                if (ret)
+                if (ret) {
+                        BUG();
                         break;
+                }
                 ret = btrfs_end_transaction(trans, tree_root);
                 BUG_ON(ret);
 
@@ -534,10 +564,12 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
         wake_up(&cur_trans->commit_wait);
         put_transaction(cur_trans);
         put_transaction(cur_trans);
+
         if (root->fs_info->closing)
                 list_splice_init(&root->fs_info->dead_roots, &dirty_fs_roots);
         else
                 list_splice_init(&dirty_fs_roots, &root->fs_info->dead_roots);
+
         mutex_unlock(&root->fs_info->trans_mutex);
         kmem_cache_free(btrfs_trans_handle_cachep, trans);