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cfc37faaaa
Summary: Update the `FuseTest.destroyWithInitRace()` test to succeed even if the future returned by `startFuse()` completes with an exception. Even though the test waits to see the `FUSE_INIT` response sent back to the kernel, there is more initialization work performed by EdenMount after the `FUSE_RESPONSE` is sent back. This initialization code can potentially fail. At the moment the initialization code generally succeeds even if the `EdenMount` has already transitioned to the `SHUT_DOWN` state. However, I plan to change the `EdenMount` code soon to error out in this case. This currently will cause this test to fail with its existing behavior. Reviewed By: strager Differential Revision: D13503048 fbshipit-source-id: 6ff147d8679559f0520f5e6091291c3a07bba3ed
740 lines
22 KiB
C++
740 lines
22 KiB
C++
/*
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* Copyright (c) 2016-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*
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*/
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#pragma once
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#include <folly/Portability.h>
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#include <folly/SharedMutex.h>
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#include <folly/Synchronized.h>
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#include <folly/ThreadLocal.h>
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#include <folly/futures/Future.h>
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#include <folly/futures/Promise.h>
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#include <folly/logging/Logger.h>
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#include <chrono>
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#include <memory>
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#include <mutex>
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#include <optional>
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#include <shared_mutex>
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#include "eden/fs/fuse/EdenStats.h"
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#include "eden/fs/fuse/FuseChannel.h"
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#include "eden/fs/inodes/InodePtrFwd.h"
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#include "eden/fs/inodes/OverlayFileAccess.h"
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#include "eden/fs/journal/Journal.h"
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#include "eden/fs/model/ParentCommits.h"
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#include "eden/fs/service/gen-cpp2/eden_types.h"
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#include "eden/fs/store/BlobAccess.h"
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#include "eden/fs/takeover/TakeoverData.h"
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#include "eden/fs/utils/PathFuncs.h"
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namespace folly {
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class EventBase;
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class File;
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template <typename T>
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class Future;
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} // namespace folly
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namespace facebook {
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namespace eden {
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class BindMount;
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class BlobCache;
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class CheckoutConflict;
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class ClientConfig;
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class Clock;
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class DiffContext;
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class EdenDispatcher;
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class FuseChannel;
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class InodeDiffCallback;
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class InodeMap;
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class MountPoint;
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struct InodeMetadata;
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template <typename T>
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class InodeTable;
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using InodeMetadataTable = InodeTable<InodeMetadata>;
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class ObjectStore;
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class Overlay;
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class OverlayFileAccess;
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class ServerState;
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class Tree;
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class UnboundedQueueExecutor;
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class RenameLock;
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class SharedRenameLock;
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/**
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* Represents types of keys for some fb303 counters.
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*/
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enum class CounterName {
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/**
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* Represents count of loaded inodes in the current mount.
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*/
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LOADED,
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/**
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* Represents count of unloaded inodes in the current mount.
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*/
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UNLOADED
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};
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/**
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* Contains the uid and gid of the owner of the files in the mount
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*/
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struct Owner {
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uid_t uid;
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gid_t gid;
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};
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/**
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* EdenMount contains all of the data about a specific eden mount point.
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*
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* This contains:
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* - The MountPoint object which manages our FUSE interactions with the kernel.
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* - The ObjectStore object used for retreiving/storing object data.
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* - The Overlay object used for storing local changes (that have not been
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* committed/snapshotted yet).
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*/
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class EdenMount {
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public:
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using State = MountState;
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/**
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* Create a shared_ptr to an EdenMount.
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*
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* Create an EdenMount instance Using an EdenMountDeleter.
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* The caller must call initialize() after creating the EdenMount
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* instance. This is not done implicitly because the graceful
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* restart code needs to take the opportunity to update the InodeMap
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* prior to the logic in initialize() running.
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*/
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static std::shared_ptr<EdenMount> create(
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std::unique_ptr<ClientConfig> config,
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std::shared_ptr<ObjectStore> objectStore,
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std::shared_ptr<BlobCache> blobCache,
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std::shared_ptr<ServerState> serverState);
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/**
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* Asynchronous EdenMount initialization - post instantiation.
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*
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* If takeover data is specified, it is used to initialize the inode map.
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*/
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FOLLY_NODISCARD folly::Future<folly::Unit> initialize(
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const std::optional<SerializedInodeMap>& takeover = std::nullopt);
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/**
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* Destroy the EdenMount.
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*
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* This method generally does not need to be invoked directly, and will
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* instead be invoked automatically by the shared_ptr<EdenMount> returned by
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* create(), once it becomes unreferenced.
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*
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* If the EdenMount has not already been explicitly shutdown(), destroy()
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* will trigger the shutdown(). destroy() blocks until the shutdown is
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* complete, so it is advisable for callers to callers to explicitly trigger
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* shutdown() themselves if they want to ensure that the shared_ptr
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* destruction will not block on this operation.
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*/
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void destroy();
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/**
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* Shutdown the EdenMount.
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*
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* This should be called *after* the FUSE mount point has been unmounted from
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* the kernel.
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*
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* This cleans up the in-memory data associated with the EdenMount, and waits
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* for all outstanding InodeBase objects to become unreferenced and be
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* destroyed.
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*
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* If doTakeover is true, this function will return populated
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* SerializedFileHandleMap and SerializedInodeMap instances generated by
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* calling FileHandleMap::serializeMap() and InodeMap::shutdown.
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*
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* If doTakeover is false, this function will return default-constructed
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* SerializedFileHandleMap and SerializedInodeMap instances.
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*/
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folly::Future<SerializedInodeMap> shutdown(
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bool doTakeover,
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bool allowFuseNotStarted = false);
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/**
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* Get the current state of this mount.
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*
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* Note that the state may be changed by another thread immediately after this
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* method is called, so this method should primarily only be used for
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* debugging & diagnostics.
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*/
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State getState() {
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return state_.load(std::memory_order_acquire);
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}
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/**
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* Get the FUSE channel for this mount point.
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*
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* This should only be called after the mount point has been successfully
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* started. (It is the caller's responsibility to perform proper
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* synchronization here with the mount start operation. This method provides
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* no internal synchronization of its own.)
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*/
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FuseChannel* getFuseChannel() const;
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/**
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* Return the path to the mount point.
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*/
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const AbsolutePath& getPath() const;
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/**
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* Get the commit IDs of the working directory's parent commit(s).
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*/
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ParentCommits getParentCommits() const {
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return parentInfo_.rlock()->parents;
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}
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/*
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* Return bind mounts that are applied for this mount. These are based on the
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* state of the ClientConfig when this EdenMount was created.
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*/
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const std::vector<BindMount>& getBindMounts() const;
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/**
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* Return the ObjectStore used by this mount point.
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*
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* The ObjectStore is guaranteed to be valid for the lifetime of the
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* EdenMount.
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*/
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ObjectStore* getObjectStore() const {
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return objectStore_.get();
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}
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/**
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* Return Eden's blob cache.
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*
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* It is guaranteed to be valid for the lifetime of the EdenMount.
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*/
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BlobCache* getBlobCache() const {
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return blobCache_.get();
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}
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/**
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* Return the BlobAccess used by this mount point.
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*
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* The BlobAccess is guaranteed to be valid for the lifetime of the EdenMount.
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*/
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BlobAccess* getBlobAccess() {
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return &blobAccess_;
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}
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/**
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* Return the EdenDispatcher used for this mount.
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*/
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EdenDispatcher* getDispatcher() const {
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return dispatcher_.get();
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}
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/**
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* Return the InodeMap for this mount.
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*/
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InodeMap* getInodeMap() const {
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return inodeMap_.get();
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}
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/**
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* Return the Overlay for this mount.
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*/
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Overlay* getOverlay() const {
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return overlay_.get();
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}
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OverlayFileAccess* getOverlayFileAccess() {
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return &overlayFileAccess_;
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}
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InodeMetadataTable* getInodeMetadataTable() const;
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Journal& getJournal() {
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return journal_;
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}
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uint64_t getMountGeneration() const {
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return mountGeneration_;
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}
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const ClientConfig* getConfig() const {
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return config_.get();
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}
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/**
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* Returns the server's thread pool.
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*/
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const std::shared_ptr<UnboundedQueueExecutor>& getThreadPool() const;
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/**
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* Returns the Clock with which this mount was configured.
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*/
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const Clock& getClock() const {
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return *clock_;
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}
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/** Get the TreeInode for the root of the mount. */
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TreeInodePtr getRootInode() const;
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/**
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* Get the inode number for the .eden dir. Returns an empty InodeNumber
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* prior to the .eden directory being set up.
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*/
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InodeNumber getDotEdenInodeNumber() const;
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/** Convenience method for getting the Tree for the root of the mount. */
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std::shared_ptr<const Tree> getRootTree() const;
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folly::Future<std::shared_ptr<const Tree>> getRootTreeFuture() const;
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/**
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* Look up the Inode object for the specified path.
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*
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* This may fail with an InodeError containing ENOENT if the path does not
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* exist, or ENOTDIR if one of the intermediate components along the path is
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* not a directory.
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*
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* This may also fail with other exceptions if something else goes wrong
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* besides the path being invalid (for instance, an error loading data from
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* the ObjectStore).
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*/
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folly::Future<InodePtr> getInode(RelativePathPiece path) const;
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/**
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* A blocking version of getInode().
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*
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* @return the InodeBase for the specified path or throws a std::system_error
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* with ENOENT.
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*
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* TODO: We should switch all callers to use the Future-base API, and remove
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* the blocking API.
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*/
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InodePtr getInodeBlocking(RelativePathPiece path) const;
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/**
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* Syntactic sugar for getInode().get().asTreePtr()
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*
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* TODO: We should switch all callers to use the Future-base API, and remove
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* the blocking API.
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*/
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TreeInodePtr getTreeInodeBlocking(RelativePathPiece path) const;
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/**
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* Syntactic sugar for getInode().get().asFilePtr()
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*
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* TODO: We should switch all callers to use the Future-base API, and remove
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* the blocking API.
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*/
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FileInodePtr getFileInodeBlocking(RelativePathPiece path) const;
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/**
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* Chases (to bounded depth) and returns the final non-symlink in the
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* (possibly 0-length) chain of symlinks rooted at pInode. Specifically:
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* If pInode is a file or directory, it is immediately returned.
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* If pInode is a symlink, the chain rooted at it chased down until
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* one of the following conditions:
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* 1) an entity outside this mount is encountered => error (EXDEV);
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* 2) an non-symlink item under this mount is found => this item is returned;
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* 3) a maximum depth is exceeded => error (ELOOP).
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* 4) absolute path entity is encountered => error (EPERM).
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* 5) the input inode refers to an unlinked inode => error (ENOENT).
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* 6) a symlink points to a non-existing entity => error (ENOENT)
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* NOTE: a loop in the chain is handled by max depth length logic.
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*/
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folly::Future<InodePtr> resolveSymlink(InodePtr pInode) const;
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/**
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* Check out the specified commit.
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*/
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folly::Future<std::vector<CheckoutConflict>> checkout(
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Hash snapshotHash,
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CheckoutMode checkoutMode = CheckoutMode::NORMAL);
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/**
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* Chown the repository to the given uid and gid
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*/
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folly::Future<folly::Unit> chown(uid_t uid, gid_t gid);
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/**
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* This version of diff is primarily intended for testing.
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* Use diff(InodeDiffCallback* callback, bool listIgnored) instead.
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* The caller must ensure that the DiffContext object ctsPtr points to
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* exists at least until the returned Future completes.
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*/
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folly::Future<folly::Unit> diff(const DiffContext* ctxPtr, Hash commitHash)
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const;
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/**
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* Compute differences between the current commit and the working directory
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* state.
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*
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* @param callback This callback will be invoked as differences are found.
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* Note that the callback methods may be invoked simultaneously from
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* multiple different threads, and the callback is responsible for
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* performing synchronization (if it is needed).
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* @param listIgnored Whether or not to inform the callback of ignored files.
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* When listIgnored is set to false can speed up the diff computation, as
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* the code does not need to descend into ignored directories at all.
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*
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* @return Returns a folly::Future that will be fulfilled when the diff
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* operation is complete. This is marked FOLLY_NODISCARD to
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* make sure callers do not forget to wait for the operation to complete.
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*/
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FOLLY_NODISCARD folly::Future<folly::Unit> diff(
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InodeDiffCallback* callback,
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Hash commitHash,
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bool listIgnored = false) const;
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/**
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* Reset the state to point to the specified parent commit(s), without
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* modifying the working directory contents at all.
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*/
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void resetParents(const ParentCommits& parents);
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/**
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* Reset the state to point to the specified parent commit, without
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* modifying the working directory contents at all.
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*
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* This is a small wrapper around resetParents() for when the code knows at
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* compile time that it will only ever have a single parent commit on this
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* code path.
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*/
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void resetParent(const Hash& parent);
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/**
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* Acquire the rename lock in exclusive mode.
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*/
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RenameLock acquireRenameLock();
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/**
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* Acquire the rename lock in shared mode.
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*/
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SharedRenameLock acquireSharedRenameLock();
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/**
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* Returns a pointer to a stats instance associated with this mountpoint.
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* Today this is the global stats instance, but in the future it will be
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* a mount point specific instance.
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*/
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ThreadLocalEdenStats* getStats() const;
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folly::Logger& getStraceLogger() {
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return straceLogger_;
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}
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/**
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* Returns the last checkout time in the Eden mount.
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*/
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struct timespec getLastCheckoutTime() const;
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/**
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* Set the last checkout time.
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*
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* This is intended primarily for use in test code.
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*/
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void setLastCheckoutTime(std::chrono::system_clock::time_point time);
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/**
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* Returns the key value to an fb303 counter.
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*/
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std::string getCounterName(CounterName name);
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struct ParentInfo {
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ParentCommits parents;
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};
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/**
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* Mounts the filesystem in the VFS and spawns worker threads to
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* dispatch the fuse session.
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*
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* Returns a Future that will complete as soon as the filesystem has been
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* successfully mounted, or as soon as the mount fails (state transitions
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* to RUNNING or FUSE_ERROR).
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*/
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FOLLY_NODISCARD folly::Future<folly::Unit> startFuse();
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/**
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* Take over a FUSE channel for an existing mount point.
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*
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* This spins up worker threads to service the existing FUSE channel and
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* returns immediately, or throws an exception on error.
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*/
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void takeoverFuse(FuseChannelData takeoverData);
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/**
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* Obtains a future that will complete once the fuse channel has wound down.
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*
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* This method may be called at any time, but the returned future will only be
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* fulfilled if startFuse() completes successfully. If startFuse() fails or
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* is never called, the future returned by getFuseCompletionFuture() will
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* never complete.
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*/
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FOLLY_NODISCARD folly::Future<TakeoverData::MountInfo>
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getFuseCompletionFuture();
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Owner getOwner() const {
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return *owner_.rlock();
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}
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void setOwner(uid_t uid, gid_t gid) {
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auto owner = owner_.wlock();
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owner->uid = uid;
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owner->gid = gid;
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}
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/**
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* Return a new stat structure that has been minimally initialized with
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* data for this mount point.
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*
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* The caller must still initialize all file-specific data (inode number,
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* file mode, size, timestamps, link count, etc).
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*/
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struct stat initStatData() const;
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/**
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* Given a mode_t, return an initial InodeMetadata. All timestamps are set
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* to the last checkout time and uid and gid are set to the creator of the
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* mount.
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*/
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struct InodeMetadata getInitialInodeMetadata(mode_t mode) const;
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/**
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* mount any configured bind mounts.
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* This requires that the filesystem already be mounted, and must not
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* be called in the context of a fuseWorkerThread().
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*/
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FOLLY_NODISCARD folly::Future<folly::Unit> performBindMounts();
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/**
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* Ensures the path `fromRoot` is a directory. If it is not, then it creates
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* subdirectories until it is. If creating a subdirectory fails, it throws an
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* exception.
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*/
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FOLLY_NODISCARD folly::Future<folly::Unit> ensureDirectoryExists(
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RelativePathPiece fromRoot);
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private:
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friend class RenameLock;
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friend class SharedRenameLock;
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class JournalDiffCallback;
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|
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/**
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* Recursive method used for resolveSymlink() implementation
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*/
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folly::Future<InodePtr>
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resolveSymlinkImpl(InodePtr pInode, RelativePath&& path, size_t depth) const;
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|
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/**
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* Attempt to transition from expected -> newState.
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* If the current state is expected then the state is set to newState
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* and returns boolean.
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* Otherwise the current state is left untouched and returns false.
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|
*/
|
|
bool doStateTransition(State expected, State newState);
|
|
|
|
EdenMount(
|
|
std::unique_ptr<ClientConfig> config,
|
|
std::shared_ptr<ObjectStore> objectStore,
|
|
std::shared_ptr<BlobCache> blobCache,
|
|
std::shared_ptr<ServerState> serverState);
|
|
|
|
// Forbidden copy constructor and assignment operator
|
|
EdenMount(EdenMount const&) = delete;
|
|
EdenMount& operator=(EdenMount const&) = delete;
|
|
|
|
folly::Future<TreeInodePtr> createRootInode(
|
|
const ParentCommits& parentCommits);
|
|
FOLLY_NODISCARD folly::Future<folly::Unit> setupDotEden(TreeInodePtr root);
|
|
folly::Future<SerializedInodeMap> shutdownImpl(bool doTakeover);
|
|
|
|
std::unique_ptr<DiffContext> createDiffContext(
|
|
InodeDiffCallback* callback,
|
|
bool listIgnored) const;
|
|
|
|
/**
|
|
* Construct the channel_ member variable.
|
|
*/
|
|
void createFuseChannel(folly::File fuseDevice);
|
|
|
|
/**
|
|
* Once the FuseChannel has been initialized, set up callbacks to clean up
|
|
* correctly when the channel shuts down.
|
|
*/
|
|
void fuseInitSuccessful(FuseChannel::StopFuture&& fuseCompleteFuture);
|
|
|
|
/**
|
|
* Private destructor.
|
|
*
|
|
* This should not be invoked by callers directly. Use the destroy() method
|
|
* above (or the EdenMountDeleter if you plan to store the EdenMount in a
|
|
* std::unique_ptr or std::shared_ptr).
|
|
*/
|
|
~EdenMount();
|
|
|
|
static constexpr int kMaxSymlinkChainDepth = 40; // max depth of symlink chain
|
|
|
|
const std::unique_ptr<const ClientConfig> config_;
|
|
|
|
/**
|
|
* A promise associated with the future returned from
|
|
* EdenMount::getFuseCompletionFuture() that completes when the
|
|
* fuseChannel has no work remaining and can be torn down.
|
|
* The future yields the underlying fuseDevice descriptor; it can
|
|
* be passed on during graceful restart or simply closed if we're
|
|
* unmounting and shutting down completely. In the unmount scenario
|
|
* the device should be closed prior to calling EdenMount::shutdown()
|
|
* so that the subsequent privilegedFuseUnmount() call won't block
|
|
* waiting on us for a response.
|
|
*/
|
|
folly::Promise<TakeoverData::MountInfo> fuseCompletionPromise_;
|
|
|
|
/**
|
|
* Eden server state shared across multiple mount points.
|
|
*/
|
|
std::shared_ptr<ServerState> serverState_;
|
|
|
|
std::unique_ptr<InodeMap> inodeMap_;
|
|
std::unique_ptr<EdenDispatcher> dispatcher_;
|
|
std::shared_ptr<ObjectStore> objectStore_;
|
|
std::shared_ptr<BlobCache> blobCache_;
|
|
BlobAccess blobAccess_;
|
|
std::unique_ptr<Overlay> overlay_;
|
|
OverlayFileAccess overlayFileAccess_;
|
|
InodeNumber dotEdenInodeNumber_{};
|
|
|
|
/**
|
|
* A mutex around all name-changing operations in this mount point.
|
|
*
|
|
* This includes rename() operations as well as unlink() and rmdir().
|
|
* Any operation that modifies an existing InodeBase's location_ data must
|
|
* hold the rename lock.
|
|
*/
|
|
folly::SharedMutex renameMutex_;
|
|
|
|
/**
|
|
* The IDs of the parent commit(s) of the working directory.
|
|
*
|
|
* In most circumstances there will only be a single parent, but there
|
|
* will be two parents when in the middle of resolving a merge conflict.
|
|
*/
|
|
|
|
folly::Synchronized<ParentInfo> parentInfo_;
|
|
|
|
/*
|
|
* Note that this config will not be updated if the user modifies the
|
|
* underlying config files after the ClientConfig was created.
|
|
*/
|
|
const std::vector<BindMount> bindMounts_;
|
|
|
|
Journal journal_;
|
|
|
|
/**
|
|
* A number to uniquely identify this particular incarnation of this mount.
|
|
* We use bits from the process id and the time at which we were mounted.
|
|
*/
|
|
const uint64_t mountGeneration_;
|
|
|
|
/**
|
|
* The path to the unix socket that can be used to address us via thrift
|
|
*/
|
|
AbsolutePath socketPath_;
|
|
|
|
/**
|
|
* A log category for logging strace-events for this mount point.
|
|
*
|
|
* All FUSE operations to this mount point will get logged to this category.
|
|
* The category name is of the following form: "eden.strace.<mount_path>"
|
|
*/
|
|
folly::Logger straceLogger_;
|
|
|
|
/**
|
|
* The timestamp of the last time that a checkout operation was performed in
|
|
* this mount. This is used to initialize the timestamps of newly loaded
|
|
* inodes. (Since the file contents might have logically been update by the
|
|
* checkout operation.)
|
|
*
|
|
* We store this as a struct timespec rather than a std::chrono::time_point
|
|
* since this is primarily used by FUSE APIs which need a timespec.
|
|
*
|
|
* This is managed with its own Synchronized lock separate from other state
|
|
* since it needs to be accessed when constructing inodes. This is a very
|
|
* low level lock in our lock ordering hierarchy: No other locks should be
|
|
* acquired while holding this lock.
|
|
*/
|
|
folly::Synchronized<struct timespec> lastCheckoutTime_;
|
|
|
|
/**
|
|
* The current state of the mount point.
|
|
*/
|
|
std::atomic<State> state_{State::UNINITIALIZED};
|
|
|
|
/**
|
|
* uid and gid that we'll set as the owners in the stat information
|
|
* returned via initStatData().
|
|
*/
|
|
folly::Synchronized<Owner> owner_;
|
|
|
|
/**
|
|
* The associated fuse channel to the kernel.
|
|
*/
|
|
std::unique_ptr<FuseChannel, FuseChannelDeleter> channel_;
|
|
|
|
/**
|
|
* The clock. This is also available as serverState_->getClock().
|
|
* We still keep it as a separate member variable for now so that getClock()
|
|
* can be inline without having to include ServerState.h in this file.
|
|
*/
|
|
std::shared_ptr<Clock> clock_;
|
|
};
|
|
|
|
/**
|
|
* RenameLock is a holder for an EdenMount's rename mutex.
|
|
*
|
|
* This is primarily useful so it can be forward declared easily,
|
|
* but it also provides a helper method to ensure that it is currently holding
|
|
* a lock on the desired mount.
|
|
*/
|
|
class RenameLock : public std::unique_lock<folly::SharedMutex> {
|
|
public:
|
|
RenameLock() {}
|
|
explicit RenameLock(EdenMount* mount)
|
|
: std::unique_lock<folly::SharedMutex>{mount->renameMutex_} {}
|
|
|
|
bool isHeld(EdenMount* mount) const {
|
|
return owns_lock() && (mutex() == &mount->renameMutex_);
|
|
}
|
|
};
|
|
|
|
/**
|
|
* SharedRenameLock is a holder for an EdenMount's rename mutex in shared mode.
|
|
*/
|
|
class SharedRenameLock : public std::shared_lock<folly::SharedMutex> {
|
|
public:
|
|
explicit SharedRenameLock(EdenMount* mount)
|
|
: std::shared_lock<folly::SharedMutex>{mount->renameMutex_} {}
|
|
|
|
bool isHeld(EdenMount* mount) const {
|
|
return owns_lock() && (mutex() == &mount->renameMutex_);
|
|
}
|
|
};
|
|
|
|
/**
|
|
* EdenMountDeleter acts as a deleter argument for std::shared_ptr or
|
|
* std::unique_ptr.
|
|
*/
|
|
class EdenMountDeleter {
|
|
public:
|
|
void operator()(EdenMount* mount) {
|
|
mount->destroy();
|
|
}
|
|
};
|
|
|
|
} // namespace eden
|
|
} // namespace facebook
|