mirror of
https://github.com/facebook/sapling.git
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3f046593a8
Summary: 1. Added a new structure `InodeBase::InodeTimestamps` to wrap atime,ctime,mtime together. This new structure helps in avoiding usage of `struct stat` for timestamps. 2. Modified function `Overlay::openFile` ,`Overlay::updateTimestampToHeader`, `Overlay::deserializeOverlayDir`, `Overlay::parseHeader` to use this new structure for timestamps instead of `struct stat`. Also, modified code in places where this change is being affected. 3. Added new helper methods `FileInode::setattrTimes` and `TreeInode::setattrTimes` to set timestamps in FileInode and TreeInode during setattr. Implementation of setattr for FileInode and TreeInode is in the diffs stacked above this diff. 4. Replaced atime, ctime, mtime in `FileInode::State`, `TreeInode::Dir` to `FileInode::State::timeStamps` and `TreeInode::State::timeStamps`. Made other necessary changes to support this change. Reviewed By: simpkins Differential Revision: D5596854 fbshipit-source-id: 2786b7b695508a62fdf8f7829f1ce76054b61c52
144 lines
4.3 KiB
C++
144 lines
4.3 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/File.h>
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#include <folly/Optional.h>
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#include <folly/Range.h>
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#include "TreeInode.h"
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#include "eden/fs/utils/DirType.h"
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#include "eden/fs/utils/PathFuncs.h"
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#include "eden/fs/utils/PathMap.h"
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namespace facebook {
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namespace eden {
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namespace overlay {
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class OverlayDir;
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}
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/** Manages the write overlay storage area.
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*
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* The overlay is where we store files that are not yet part of a snapshot.
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*
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* The contents of this storage layer are overlaid on top of the object store
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* snapshot that is active in a given mount point.
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*
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* There is one overlay area associated with each eden client instance.
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*
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* We use the Overlay to manage mutating the structure of the checkout;
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* each time we create or delete a directory entry, we do so through
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* the overlay class.
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*
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* The Overlay class keeps track of the mutated tree; if we mutate some
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* file "foo/bar/baz" then the Overlay records metadata about the list
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* of files in the root, the list of files in "foo", the list of files in
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* "foo/bar" and finally materializes "foo/bar/baz".
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*/
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class Overlay {
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public:
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explicit Overlay(AbsolutePathPiece localDir);
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/** Returns the path to the root of the Overlay storage area */
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const AbsolutePath& getLocalDir() const;
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void saveOverlayDir(fuse_ino_t inodeNumber, const TreeInode::Dir* dir);
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folly::Optional<TreeInode::Dir> loadOverlayDir(fuse_ino_t inodeNumber) const;
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void removeOverlayData(fuse_ino_t inodeNumber) const;
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/**
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* Get the path to the overlay file for the given inode
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*/
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AbsolutePath getFilePath(fuse_ino_t inodeNumber) const;
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/**
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* Creates header for the files stored in Overlay
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*/
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static folly::IOBuf createHeader(
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folly::StringPiece identifier,
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uint32_t version,
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const struct timespec& atime,
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const struct timespec& ctime,
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const struct timespec& mtime);
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/**
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* Helper function that opens an existing overlay file,
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* checks if the file has valid header
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* populates st_atim, st_mtim, st_ctim and returns the file.
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*/
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static folly::File openFile(
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folly::StringPiece filePath,
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folly::StringPiece headerId,
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InodeBase::InodeTimestamps& timestamps);
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/**
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* Helper function that creates a new overlay file and adds header to it
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*/
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folly::File createOverlayFile(fuse_ino_t childNumber);
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/**
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* Updates the timestamps of an overlay file appropriately
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* while unloading an inode.
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*/
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static void updateTimestampToHeader(
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int fd,
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const InodeBase::InodeTimestamps& timeStamps);
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/**
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* Get the maximum inode number stored in the overlay.
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*
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* This is called when opening a mount point, to make sure that new inodes
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* handed out from this point forwards are always greater than any inodes
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* already tracked in the overlay.
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*/
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fuse_ino_t getMaxRecordedInode();
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/**
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* Constants for an header in overlay file.
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*/
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static constexpr folly::StringPiece kHeaderIdentifierDir{"OVDR"};
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static constexpr folly::StringPiece kHeaderIdentifierFile{"OVFL"};
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static constexpr uint32_t kHeaderVersion = 1;
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static constexpr size_t kHeaderLength = 64;
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private:
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void initOverlay();
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bool isOldFormatOverlay() const;
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void readExistingOverlay(int infoFD);
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void initNewOverlay();
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folly::Optional<overlay::OverlayDir> deserializeOverlayDir(
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fuse_ino_t inodeNumber,
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InodeBase::InodeTimestamps& timeStamps) const;
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/**
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* Helper function to add header to the overlay file
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*/
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static void addHeaderToOverlayFile(int fd);
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/**
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* Parses, validates and reads Timestamps from the header.
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*/
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static void parseHeader(
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folly::StringPiece header,
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folly::StringPiece headerId,
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InodeBase::InodeTimestamps& timeStamps);
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/** path to ".eden/CLIENT/local" */
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AbsolutePath localDir_;
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/**
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* An open file descriptor to the overlay info file.
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*
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* This is primarily used to hold a lock on the overlay for as long as we are
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* using it. We want to ensure that only one eden process
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*/
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folly::File infoFile_;
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};
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}
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}
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