static int create_snapshot(struct btrfs_root *root, struct dentry *dentry, char *name, int namelen) { struct inode *inode; struct btrfs_pending_snapshot *pending_snapshot; struct btrfs_trans_handle *trans; int ret; if (!root->ref_cows) return -EINVAL; /* * 1 - inode item * 2 - refs * 1 - root item * 2 - dir items */ ret = btrfs_reserve_metadata_space(root, 6); if (ret) goto fail; pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_NOFS); if (!pending_snapshot) { ret = -ENOMEM; btrfs_unreserve_metadata_space(root, 6); goto fail; } pending_snapshot->name = kmalloc(namelen + 1, GFP_NOFS); if (!pending_snapshot->name) { ret = -ENOMEM; kfree(pending_snapshot); btrfs_unreserve_metadata_space(root, 6); goto fail; } memcpy(pending_snapshot->name, name, namelen); pending_snapshot->name[namelen] = '\0'; pending_snapshot->dentry = dentry; trans = btrfs_start_transaction(root, 1); BUG_ON(!trans); pending_snapshot->root = root; list_add(&pending_snapshot->list, &trans->transaction->pending_snapshots); ret = btrfs_commit_transaction(trans, root); BUG_ON(ret); btrfs_unreserve_metadata_space(root, 6); inode = btrfs_lookup_dentry(dentry->d_parent->d_inode, dentry); if (IS_ERR(inode)) { ret = PTR_ERR(inode); goto fail; } BUG_ON(!inode); d_instantiate(dentry, inode); ret = 0; fail: return ret; }
int __btrfs_setxattr(struct btrfs_trans_handle *trans, struct inode *inode, const char *name, const void *value, size_t size, int flags) { struct btrfs_root *root = BTRFS_I(inode)->root; int ret; if (trans) return do_setxattr(trans, inode, name, value, size, flags); ret = btrfs_reserve_metadata_space(root, 2); if (ret) return ret; trans = btrfs_start_transaction(root, 1); if (!trans) { ret = -ENOMEM; goto out; } btrfs_set_trans_block_group(trans, inode); ret = do_setxattr(trans, inode, name, value, size, flags); if (ret) goto out; inode->i_ctime = CURRENT_TIME; ret = btrfs_update_inode(trans, root, inode); BUG_ON(ret); out: btrfs_end_transaction_throttle(trans, root); btrfs_unreserve_metadata_space(root, 2); return ret; }
/* * new snapshots need to be created at a very specific time in the * transaction commit. This does the actual creation */ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, struct btrfs_pending_snapshot *pending) { struct btrfs_key key; struct btrfs_root_item *new_root_item; struct btrfs_root *tree_root = fs_info->tree_root; struct btrfs_root *root = pending->root; struct extent_buffer *tmp; struct extent_buffer *old; int ret; u64 objectid; new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS); if (!new_root_item) { ret = -ENOMEM; goto fail; } ret = btrfs_find_free_objectid(trans, tree_root, 0, &objectid); if (ret) goto fail; record_root_in_trans(trans, root); btrfs_set_root_last_snapshot(&root->root_item, trans->transid); memcpy(new_root_item, &root->root_item, sizeof(*new_root_item)); key.objectid = objectid; /* 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); btrfs_cow_block(trans, root, old, NULL, 0, &old); btrfs_set_lock_blocking(old); btrfs_copy_root(trans, root, old, &tmp, objectid); btrfs_tree_unlock(old); free_extent_buffer(old); btrfs_set_root_node(new_root_item, tmp); ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key, new_root_item); btrfs_tree_unlock(tmp); free_extent_buffer(tmp); if (ret) goto fail; key.offset = (u64)-1; memcpy(&pending->root_key, &key, sizeof(key)); fail: kfree(new_root_item); btrfs_unreserve_metadata_space(root, 6); return ret; }
static noinline int create_subvol(struct btrfs_root *root, struct dentry *dentry, char *name, int namelen) { struct btrfs_trans_handle *trans; struct btrfs_key key; struct btrfs_root_item root_item; struct btrfs_inode_item *inode_item; struct extent_buffer *leaf; struct btrfs_root *new_root; struct inode *dir = dentry->d_parent->d_inode; int ret; int err; u64 objectid; u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID; u64 index = 0; /* * 1 - inode item * 2 - refs * 1 - root item * 2 - dir items */ ret = btrfs_reserve_metadata_space(root, 6); if (ret) return ret; trans = btrfs_start_transaction(root, 1); BUG_ON(!trans); ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root, 0, &objectid); if (ret) goto fail; leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0, objectid, NULL, 0, 0, 0); if (IS_ERR(leaf)) { ret = PTR_ERR(leaf); goto fail; } memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header)); btrfs_set_header_bytenr(leaf, leaf->start); btrfs_set_header_generation(leaf, trans->transid); btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV); btrfs_set_header_owner(leaf, objectid); write_extent_buffer(leaf, root->fs_info->fsid, (unsigned long)btrfs_header_fsid(leaf), BTRFS_FSID_SIZE); write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid, (unsigned long)btrfs_header_chunk_tree_uuid(leaf), BTRFS_UUID_SIZE); btrfs_mark_buffer_dirty(leaf); inode_item = &root_item.inode; memset(inode_item, 0, sizeof(*inode_item)); inode_item->generation = cpu_to_le64(1); inode_item->size = cpu_to_le64(3); inode_item->nlink = cpu_to_le32(1); inode_item->nbytes = cpu_to_le64(root->leafsize); inode_item->mode = cpu_to_le32(S_IFDIR | 0755); btrfs_set_root_bytenr(&root_item, leaf->start); btrfs_set_root_generation(&root_item, trans->transid); btrfs_set_root_level(&root_item, 0); btrfs_set_root_refs(&root_item, 1); btrfs_set_root_used(&root_item, leaf->len); btrfs_set_root_last_snapshot(&root_item, 0); memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress)); root_item.drop_level = 0; btrfs_tree_unlock(leaf); free_extent_buffer(leaf); leaf = NULL; btrfs_set_root_dirid(&root_item, new_dirid); key.objectid = objectid; key.offset = 0; btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY); ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key, &root_item); if (ret) goto fail; key.offset = (u64)-1; new_root = btrfs_read_fs_root_no_name(root->fs_info, &key); BUG_ON(IS_ERR(new_root)); btrfs_record_root_in_trans(trans, new_root); ret = btrfs_create_subvol_root(trans, new_root, new_dirid, BTRFS_I(dir)->block_group); /* * insert the directory item */ ret = btrfs_set_inode_index(dir, &index); BUG_ON(ret); ret = btrfs_insert_dir_item(trans, root, name, namelen, dir->i_ino, &key, BTRFS_FT_DIR, index); if (ret) goto fail; btrfs_i_size_write(dir, dir->i_size + namelen * 2); ret = btrfs_update_inode(trans, root, dir); BUG_ON(ret); ret = btrfs_add_root_ref(trans, root->fs_info->tree_root, objectid, root->root_key.objectid, dir->i_ino, index, name, namelen); BUG_ON(ret); d_instantiate(dentry, btrfs_lookup_dentry(dir, dentry)); fail: err = btrfs_commit_transaction(trans, root); if (err && !ret) ret = err; btrfs_unreserve_metadata_space(root, 6); return ret; }