126 lines
3.5 KiB
C++
126 lines
3.5 KiB
C++
// Copyright (c) Vitaliy Filippov, 2019+
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// License: VNPL-1.1 (see README.md for details)
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#include "cli.h"
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#include "cluster_client.h"
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#include <sys/stat.h>
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// Flatten a layer: merge all parents into a layer and break the connection completely
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struct snap_flattener_t
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{
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cli_tool_t *parent;
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// target to flatten
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std::string target_name;
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// writers are stopped, we can safely change writable layers
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bool writers_stopped = false;
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// use CAS writes (0 = never, 1 = auto, 2 = always)
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int use_cas = 1;
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// interval between fsyncs
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int fsync_interval = 128;
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std::string top_parent_name;
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inode_t target_id = 0;
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int state = 0;
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std::function<bool(void)> merger_cb;
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void get_merge_parents()
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{
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// Get all parents of target
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inode_config_t *target_cfg = parent->get_inode_cfg(target_name);
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target_id = target_cfg->num;
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std::vector<inode_t> chain_list;
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inode_config_t *cur = target_cfg;
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chain_list.push_back(cur->num);
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while (cur->parent_id != 0 && cur->parent_id != target_cfg->num)
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{
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auto it = parent->cli->st_cli.inode_config.find(cur->parent_id);
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if (it == parent->cli->st_cli.inode_config.end())
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{
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fprintf(stderr, "Parent inode of layer %s (id %ld) not found\n", cur->name.c_str(), cur->parent_id);
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exit(1);
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}
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cur = &it->second;
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chain_list.push_back(cur->num);
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}
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if (cur->parent_id != 0)
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{
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fprintf(stderr, "Layer %s has a loop in parents\n", target_name.c_str());
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exit(1);
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}
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top_parent_name = cur->name;
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}
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bool is_done()
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{
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return state == 5;
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}
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void loop()
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{
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if (state == 1)
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goto resume_1;
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else if (state == 2)
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goto resume_2;
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else if (state == 3)
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goto resume_3;
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// Get parent layers
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get_merge_parents();
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// Start merger
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merger_cb = parent->start_merge(json11::Json::object {
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{ "command", json11::Json::array{ "merge-data", top_parent_name, target_name } },
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{ "target", target_name },
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{ "delete-source", false },
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{ "cas", use_cas },
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{ "fsync-interval", fsync_interval },
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});
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// Wait for it
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resume_1:
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while (!merger_cb())
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{
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state = 1;
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return;
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}
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merger_cb = NULL;
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// Change parent
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parent->change_parent(target_id, 0);
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// Wait for it to complete
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state = 2;
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resume_2:
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if (parent->waiting > 0)
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return;
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state = 3;
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resume_3:
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// Done
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return;
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}
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};
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std::function<bool(void)> cli_tool_t::start_flatten(json11::Json cfg)
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{
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json11::Json::array cmd = cfg["command"].array_items();
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auto flattener = new snap_flattener_t();
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flattener->parent = this;
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flattener->target_name = cmd.size() > 1 ? cmd[1].string_value() : "";
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if (flattener->target_name == "")
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{
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fprintf(stderr, "Layer to flatten argument is missing\n");
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exit(1);
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}
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flattener->fsync_interval = cfg["fsync-interval"].uint64_value();
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if (!flattener->fsync_interval)
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flattener->fsync_interval = 128;
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if (!cfg["cas"].is_null())
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flattener->use_cas = cfg["cas"].uint64_value() ? 2 : 0;
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return [flattener]()
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{
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flattener->loop();
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if (flattener->is_done())
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{
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delete flattener;
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return true;
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}
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return false;
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};
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}
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