Btrfs: add snapshot/subvolume destroy ioctl

[cascardo/linux.git] / fs / btrfs / transaction.c

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index e51d2bc..88f866f 100644 (file)
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -42,10 +42,8 @@ static noinline void put_transaction(struct btrfs_transaction *transaction)
 
 static noinline void switch_commit_root(struct btrfs_root *root)
 {
-       down_write(&root->commit_root_sem);
        free_extent_buffer(root->commit_root);
        root->commit_root = btrfs_root_node(root);
-       up_write(&root->commit_root_sem);
 }
 
 /*
@@ -106,7 +104,6 @@ static noinline int record_root_in_trans(struct btrfs_trans_handle *trans,
 {
        if (root->ref_cows && root->last_trans < trans->transid) {
                WARN_ON(root == root->fs_info->extent_root);
-               WARN_ON(root->root_item.refs == 0);
                WARN_ON(root->commit_root != root->node);
 
                radix_tree_tag_set(&root->fs_info->fs_roots_radix,
@@ -466,7 +463,10 @@ static int update_cowonly_root(struct btrfs_trans_handle *trans,
                ret = btrfs_write_dirty_block_groups(trans, root);
                BUG_ON(ret);
        }
-       switch_commit_root(root);
+
+       if (root != root->fs_info->extent_root)
+               switch_commit_root(root);
+
        return 0;
 }
 
@@ -499,6 +499,11 @@ static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
 
                update_cowonly_root(trans, root);
        }
+
+       down_write(&fs_info->extent_commit_sem);
+       switch_commit_root(fs_info->extent_root);
+       up_write(&fs_info->extent_commit_sem);
+
        return 0;
 }
 
@@ -714,7 +719,8 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
        memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
 
        key.objectid = objectid;
-       key.offset = 0;
+       /* record when the snapshot was created in key.offset */
+       key.offset = trans->transid;
        btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 
        old = btrfs_lock_root_node(root);
@@ -772,24 +778,14 @@ static noinline int finish_pending_snapshot(struct btrfs_fs_info *fs_info,
        ret = btrfs_update_inode(trans, parent_root, parent_inode);
        BUG_ON(ret);
 
-       /* add the backref first */
        ret = btrfs_add_root_ref(trans, parent_root->fs_info->tree_root,
                                 pending->root_key.objectid,
-                                BTRFS_ROOT_BACKREF_KEY,
                                 parent_root->root_key.objectid,
                                 parent_inode->i_ino, index, pending->name,
                                 namelen);
 
        BUG_ON(ret);
 
-       /* now add the forward ref */
-       ret = btrfs_add_root_ref(trans, parent_root->fs_info->tree_root,
-                                parent_root->root_key.objectid,
-                                BTRFS_ROOT_REF_KEY,
-                                pending->root_key.objectid,
-                                parent_inode->i_ino, index, pending->name,
-                                namelen);
-
        inode = btrfs_lookup_dentry(parent_inode, pending->dentry);
        d_instantiate(pending->dentry, inode);
 fail:
@@ -851,6 +847,16 @@ static void update_super_roots(struct btrfs_root *root)
        super->root_level = root_item->level;
 }
 
+int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
+{
+       int ret = 0;
+       spin_lock(&info->new_trans_lock);
+       if (info->running_transaction)
+               ret = info->running_transaction->in_commit;
+       spin_unlock(&info->new_trans_lock);
+       return ret;
+}
+
 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                             struct btrfs_root *root)
 {
@@ -858,7 +864,6 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
        unsigned long timeout = 1;
        struct btrfs_transaction *cur_trans;
        struct btrfs_transaction *prev_trans = NULL;
-       struct extent_io_tree *pinned_copy;
        DEFINE_WAIT(wait);
        int ret;
        int should_grow = 0;
@@ -899,13 +904,6 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                return 0;
        }
 
-       pinned_copy = kmalloc(sizeof(*pinned_copy), GFP_NOFS);
-       if (!pinned_copy)
-               return -ENOMEM;
-
-       extent_io_tree_init(pinned_copy,
-                            root->fs_info->btree_inode->i_mapping, GFP_NOFS);
-
        trans->transaction->in_commit = 1;
        trans->transaction->blocked = 1;
        if (cur_trans->list.prev != &root->fs_info->trans_list) {
@@ -1003,6 +1001,8 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
        ret = commit_cowonly_roots(trans, root);
        BUG_ON(ret);
 
+       btrfs_prepare_extent_commit(trans, root);
+
        cur_trans = root->fs_info->running_transaction;
        spin_lock(&root->fs_info->new_trans_lock);
        root->fs_info->running_transaction = NULL;
@@ -1026,8 +1026,6 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
        memcpy(&root->fs_info->super_for_commit, &root->fs_info->super_copy,
               sizeof(root->fs_info->super_copy));
 
-       btrfs_copy_pinned(root, pinned_copy);
-
        trans->transaction->blocked = 0;
 
        wake_up(&root->fs_info->transaction_wait);
@@ -1043,8 +1041,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
         */
        mutex_unlock(&root->fs_info->tree_log_mutex);
 
-       btrfs_finish_extent_commit(trans, root, pinned_copy);
-       kfree(pinned_copy);
+       btrfs_finish_extent_commit(trans, root);
 
        /* do the directory inserts of any pending snapshot creations */
        finish_pending_snapshots(trans, root->fs_info);
@@ -1080,8 +1077,13 @@ int btrfs_clean_old_snapshots(struct btrfs_root *root)
 
        while (!list_empty(&list)) {
                root = list_entry(list.next, struct btrfs_root, root_list);
-               list_del_init(&root->root_list);
-               btrfs_drop_snapshot(root, 0);
+               list_del(&root->root_list);
+
+               if (btrfs_header_backref_rev(root->node) <
+                   BTRFS_MIXED_BACKREF_REV)
+                       btrfs_drop_snapshot(root, 0);
+               else
+                       btrfs_drop_snapshot(root, 1);
        }
        return 0;
 }