It turns out that ZFS doesn't do any normalization when storing files, but does do normalization "as part of any comparison process". In practice, this seems to mean that if you LStat a normalized filename, ZFS will return the FileInfo for the un-normalized version of that filename. This meant that our test to see whether a separate file with a normalized version of the filename already exists was failing, as we were detecting the same file. The fix is to use os.SameFile, to see whether we're getting the same FileInfo from the normalized and un-normalized versions of the same filename. One complication is that ZFS also seems to apply its magic to os.Rename, meaning that we can't use it to rename an un-normalized file to its normalized filename. Instead we have to move via a temporary object. If the move to the temporary object fails, that's OK, we can skip it and move on. If the move from the temporary object fails however, I'm not sure of the best approach: the current one is to leave the temporary file name as-is, and get Syncthing to syncronize it, so at least we don't lose the file. I'm not sure if there are any implications of this however. As part of reworking normalizePath, I spotted that it appeared to be returning the wrong thing: the doc and the surrounding code expecting it to return the normalized filename, but it was returning the un-normalized one. I fixed this, but it seems suspicious that, if the previous behaviour was incorrect, noone ever ran afoul of it. Maybe all filesystems will do some searching and give you a normalized filename if you request an unnormalized one. As part of this, I found that TestNormalization was broken: it was passing, when in fact one of the files it should have verified was present was missing. Maybe this was related to the above issue with normalizePath's return value, I'm not sure. Fixed en route. Kindly tested by @khinsen on the forum, and it appears to work. GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4646
196 lines
5.0 KiB
Go
196 lines
5.0 KiB
Go
// Copyright (C) 2016 The Syncthing Authors.
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this file,
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// You can obtain one at https://mozilla.org/MPL/2.0/.
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package fs
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import (
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"context"
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"errors"
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"io"
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"os"
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"path/filepath"
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"strings"
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"time"
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)
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// The Filesystem interface abstracts access to the file system.
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type Filesystem interface {
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Chmod(name string, mode FileMode) error
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Chtimes(name string, atime time.Time, mtime time.Time) error
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Create(name string) (File, error)
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CreateSymlink(name, target string) error
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DirNames(name string) ([]string, error)
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Lstat(name string) (FileInfo, error)
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Mkdir(name string, perm FileMode) error
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MkdirAll(name string, perm FileMode) error
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Open(name string) (File, error)
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OpenFile(name string, flags int, mode FileMode) (File, error)
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ReadSymlink(name string) (string, error)
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Remove(name string) error
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RemoveAll(name string) error
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Rename(oldname, newname string) error
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Stat(name string) (FileInfo, error)
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SymlinksSupported() bool
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Walk(name string, walkFn WalkFunc) error
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Watch(path string, ignore Matcher, ctx context.Context, ignorePerms bool) (<-chan Event, error)
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Hide(name string) error
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Unhide(name string) error
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Glob(pattern string) ([]string, error)
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Roots() ([]string, error)
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Usage(name string) (Usage, error)
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Type() FilesystemType
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URI() string
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SameFile(fi1, fi2 FileInfo) bool
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}
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// The File interface abstracts access to a regular file, being a somewhat
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// smaller interface than os.File
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type File interface {
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io.Closer
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io.Reader
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io.ReaderAt
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io.Seeker
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io.Writer
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io.WriterAt
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Name() string
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Truncate(size int64) error
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Stat() (FileInfo, error)
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Sync() error
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}
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// The FileInfo interface is almost the same as os.FileInfo, but with the
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// Sys method removed (as we don't want to expose whatever is underlying)
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// and with a couple of convenience methods added.
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type FileInfo interface {
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// Standard things present in os.FileInfo
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Name() string
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Mode() FileMode
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Size() int64
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ModTime() time.Time
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IsDir() bool
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// Extensions
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IsRegular() bool
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IsSymlink() bool
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}
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// FileMode is similar to os.FileMode
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type FileMode uint32
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// Usage represents filesystem space usage
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type Usage struct {
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Free int64
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Total int64
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}
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type Matcher interface {
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ShouldIgnore(name string) bool
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}
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type MatchResult interface {
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IsIgnored() bool
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}
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type Event struct {
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Name string
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Type EventType
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}
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type EventType int
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const (
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NonRemove EventType = 1 + iota
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Remove
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Mixed // Should probably not be necessary to be used in filesystem interface implementation
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)
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func (evType EventType) String() string {
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switch {
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case evType == NonRemove:
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return "non-remove"
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case evType == Remove:
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return "remove"
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case evType == Mixed:
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return "mixed"
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default:
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panic("bug: Unknown event type")
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}
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}
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var ErrWatchNotSupported = errors.New("watching is not supported")
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// Equivalents from os package.
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const ModePerm = FileMode(os.ModePerm)
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const ModeSetgid = FileMode(os.ModeSetgid)
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const ModeSetuid = FileMode(os.ModeSetuid)
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const ModeSticky = FileMode(os.ModeSticky)
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const ModeSymlink = FileMode(os.ModeSymlink)
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const ModeType = FileMode(os.ModeType)
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const PathSeparator = os.PathSeparator
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const OptAppend = os.O_APPEND
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const OptCreate = os.O_CREATE
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const OptExclusive = os.O_EXCL
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const OptReadOnly = os.O_RDONLY
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const OptReadWrite = os.O_RDWR
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const OptSync = os.O_SYNC
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const OptTruncate = os.O_TRUNC
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const OptWriteOnly = os.O_WRONLY
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// SkipDir is used as a return value from WalkFuncs to indicate that
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// the directory named in the call is to be skipped. It is not returned
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// as an error by any function.
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var SkipDir = filepath.SkipDir
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// IsExist is the equivalent of os.IsExist
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var IsExist = os.IsExist
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// IsNotExist is the equivalent of os.IsNotExist
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var IsNotExist = os.IsNotExist
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// IsPermission is the equivalent of os.IsPermission
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var IsPermission = os.IsPermission
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// IsPathSeparator is the equivalent of os.IsPathSeparator
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var IsPathSeparator = os.IsPathSeparator
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func NewFilesystem(fsType FilesystemType, uri string) Filesystem {
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var fs Filesystem
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switch fsType {
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case FilesystemTypeBasic:
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fs = NewWalkFilesystem(newBasicFilesystem(uri))
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default:
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l.Debugln("Unknown filesystem", fsType, uri)
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fs = &errorFilesystem{
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fsType: fsType,
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uri: uri,
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err: errors.New("filesystem with type " + fsType.String() + " does not exist."),
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}
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}
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if l.ShouldDebug("filesystem") {
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fs = &logFilesystem{fs}
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}
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return fs
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}
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// IsInternal returns true if the file, as a path relative to the folder
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// root, represents an internal file that should always be ignored. The file
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// path must be clean (i.e., in canonical shortest form).
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func IsInternal(file string) bool {
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// fs cannot import config, so we hard code .stfolder here (config.DefaultMarkerName)
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internals := []string{".stfolder", ".stignore", ".stversions"}
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pathSep := string(PathSeparator)
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for _, internal := range internals {
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if file == internal {
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return true
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}
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if strings.HasPrefix(file, internal+pathSep) {
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return true
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}
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}
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return false
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}
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