Don't depend on fuseshim for mounting.
commit
9b4cfc818e
|
@ -32,6 +32,25 @@ import (
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"github.com/jacobsa/fuse/internal/fuseshim"
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)
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// Ask the Linux kernel for larger read requests.
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//
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// As of 2015-03-26, the behavior in the kernel is:
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//
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// * (http://goo.gl/bQ1f1i, http://goo.gl/HwBrR6) Set the local variable
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// ra_pages to be init_response->max_readahead divided by the page size.
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//
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// * (http://goo.gl/gcIsSh, http://goo.gl/LKV2vA) Set
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// backing_dev_info::ra_pages to the min of that value and what was sent
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// in the request's max_readahead field.
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//
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// * (http://goo.gl/u2SqzH) Use backing_dev_info::ra_pages when deciding
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// how much to read ahead.
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//
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// * (http://goo.gl/JnhbdL) Don't read ahead at all if that field is zero.
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//
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// Reading a page at a time is a drag. Ask for a larger size.
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const maxReadahead = 1 << 20
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// A connection to the fuse kernel process.
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type Connection struct {
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debugLogger *log.Logger
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@ -58,15 +77,27 @@ type Connection struct {
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cancelFuncs map[uint64]func()
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}
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// Responsibility for closing the wrapped connection is transferred to the
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// result. You must call c.close() eventually.
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// Create a connection wrapping the supplied file descriptor connected to the
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// kernel. You must eventually call c.close().
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//
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// The loggers may be nil.
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func newConnection(
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parentCtx context.Context,
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debugLogger *log.Logger,
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errorLogger *log.Logger,
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wrapped *fuseshim.Conn) (c *Connection, err error) {
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dev *os.File) (c *Connection, err error) {
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// Create an initialized a wrapped fuseshim connection.
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wrapped := &fuseshim.Conn{
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Dev: dev,
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}
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err = fuseshim.InitMount(wrapped, maxReadahead, 0)
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if err != nil {
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err = fmt.Errorf("fuseshim.InitMount: %v", err)
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return
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}
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// Create an object wrapping it.
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c = &Connection{
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debugLogger: debugLogger,
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errorLogger: errorLogger,
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@ -164,7 +164,7 @@ func Mount(dir string, options ...MountOption) (*Conn, error) {
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}
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c.Dev = f
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if err := initMount(c, &conf); err != nil {
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if err := InitMount(c, conf.maxReadahead, conf.initFlags); err != nil {
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c.Close()
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return nil, err
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}
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@ -181,7 +181,10 @@ func (e *OldVersionError) Error() string {
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return fmt.Sprintf("kernel FUSE version is too old: %v < %v", e.Kernel, e.LibraryMin)
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}
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func initMount(c *Conn, conf *mountConfig) error {
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func InitMount(
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c *Conn,
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maxReadahead uint32,
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initFlags fusekernel.InitFlags) error {
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req, err := c.ReadRequest()
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if err != nil {
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if err == io.EOF {
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@ -213,9 +216,9 @@ func initMount(c *Conn, conf *mountConfig) error {
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s := &InitResponse{
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Library: proto,
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MaxReadahead: conf.maxReadahead,
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MaxReadahead: maxReadahead,
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MaxWrite: maxWrite,
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Flags: fusekernel.InitBigWrites | conf.initFlags,
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Flags: fusekernel.InitBigWrites | initFlags,
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}
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r.Respond(s)
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return nil
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@ -0,0 +1,153 @@
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// Copyright 2015 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package fuse
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import (
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"fmt"
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"log"
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"runtime"
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"strings"
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"golang.org/x/net/context"
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)
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// Optional configuration accepted by Mount.
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type MountConfig struct {
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// The context from which every op read from the connetion by the sever
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// should inherit. If nil, context.Background() will be used.
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OpContext context.Context
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// If non-empty, the name of the file system as displayed by e.g. `mount`.
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// This is important because the `umount` command requires root privileges if
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// it doesn't agree with /etc/fstab.
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FSName string
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// Mount the file system in read-only mode. File modes will appear as normal,
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// but opening a file for writing and metadata operations like chmod,
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// chtimes, etc. will fail.
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ReadOnly bool
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// A logger to use for logging errors. All errors are logged, with the
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// exception of a few blacklisted errors that are expected. If nil, no error
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// logging is performed.
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ErrorLogger *log.Logger
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// A logger to use for logging debug information. If nil, no debug logging is
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// performed.
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DebugLogger *log.Logger
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// OS X only.
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//
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// Normally on OS X we mount with the novncache option
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// (cf. http://goo.gl/1pTjuk), which disables entry caching in the kernel.
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// This is because osxfuse does not honor the entry expiration values we
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// return to it, instead caching potentially forever (cf.
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// http://goo.gl/8yR0Ie), and it is probably better to fail to cache than to
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// cache for too long, since the latter is more likely to hide consistency
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// bugs that are difficult to detect and diagnose.
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//
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// This field disables the use of novncache, restoring entry caching. Beware:
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// the value of ChildInodeEntry.EntryExpiration is ignored by the kernel, and
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// entries will be cached for an arbitrarily long time.
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EnableVnodeCaching bool
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// Additional key=value options to pass unadulterated to the underlying mount
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// command. See `man 8 mount`, the fuse documentation, etc. for
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// system-specific information.
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//
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// For expert use only! May invalidate other guarantees made in the
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// documentation for this package.
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Options map[string]string
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}
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// Create a map containing all of the key=value mount options to be given to
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// the mount helper.
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func (c *MountConfig) toMap() (opts map[string]string) {
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isDarwin := runtime.GOOS == "darwin"
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opts = make(map[string]string)
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// Enable permissions checking in the kernel. See the comments on
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// InodeAttributes.Mode.
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opts["default_permissions"] = ""
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// HACK(jacobsa): Work around what appears to be a bug in systemd v219, as
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// shipped in Ubuntu 15.04, where it automatically unmounts any file system
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// that doesn't set an explicit name.
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//
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// When Ubuntu contains systemd v220, this workaround should be removed and
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// the systemd bug reopened if the problem persists.
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//
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// Cf. https://github.com/bazil/fuse/issues/89
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// Cf. https://bugs.freedesktop.org/show_bug.cgi?id=90907
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fsname := c.FSName
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if runtime.GOOS == "linux" && fsname == "" {
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fsname = "some_fuse_file_system"
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}
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// Special file system name?
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if fsname != "" {
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opts["fsname"] = fsname
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}
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// Read only?
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if c.ReadOnly {
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opts["ro"] = ""
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}
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// OS X: set novncache when appropriate.
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if isDarwin && !c.EnableVnodeCaching {
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opts["novncache"] = ""
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}
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// OS X: disable the use of "Apple Double" (._foo and .DS_Store) files, which
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// just add noise to debug output and can have significant cost on
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// network-based file systems.
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//
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// Cf. https://github.com/osxfuse/osxfuse/wiki/Mount-options
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if isDarwin {
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opts["noappledouble"] = ""
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}
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// Last but not least: other user-supplied options.
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for k, v := range c.Options {
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opts[k] = v
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}
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return
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}
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func escapeOptionsKey(s string) (res string) {
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res = s
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res = strings.Replace(res, `\`, `\\`, -1)
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res = strings.Replace(res, `,`, `\,`, -1)
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return
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}
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// Create an options string suitable for passing to the mount helper.
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func (c *MountConfig) toOptionsString() string {
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var components []string
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for k, v := range c.toMap() {
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k = escapeOptionsKey(k)
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component := k
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if v != "" {
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component = fmt.Sprintf("%s=%s", k, v)
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}
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components = append(components, component)
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}
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return strings.Join(components, ",")
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}
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@ -0,0 +1,156 @@
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package fuse
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import (
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"bytes"
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"errors"
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"fmt"
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"os"
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"os/exec"
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"strconv"
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"strings"
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"syscall"
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"github.com/jacobsa/fuse/internal/buffer"
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)
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var errNoAvail = errors.New("no available fuse devices")
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var errNotLoaded = errors.New("osxfusefs is not loaded")
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func loadOSXFUSE() error {
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cmd := exec.Command("/Library/Filesystems/osxfusefs.fs/Support/load_osxfusefs")
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cmd.Dir = "/"
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cmd.Stdout = os.Stdout
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cmd.Stderr = os.Stderr
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err := cmd.Run()
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return err
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}
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func openOSXFUSEDev() (dev *os.File, err error) {
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// Try each device name.
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for i := uint64(0); ; i++ {
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path := fmt.Sprintf("/dev/osxfuse%d", i)
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dev, err = os.OpenFile(path, os.O_RDWR, 0000)
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if os.IsNotExist(err) {
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if i == 0 {
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// Not even the first device was found. Fuse must not be loaded.
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err = errNotLoaded
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return
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}
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// Otherwise we've run out of kernel-provided devices
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err = errNoAvail
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return
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}
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if err2, ok := err.(*os.PathError); ok && err2.Err == syscall.EBUSY {
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// This device is in use; try the next one.
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continue
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}
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return
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}
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}
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func callMount(
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dir string,
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cfg *MountConfig,
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dev *os.File,
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ready chan<- error) (err error) {
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const bin = "/Library/Filesystems/osxfusefs.fs/Support/mount_osxfusefs"
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// The mount helper doesn't understand any escaping.
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for k, v := range cfg.toMap() {
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if strings.Contains(k, ",") || strings.Contains(v, ",") {
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return fmt.Errorf(
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"mount options cannot contain commas on darwin: %q=%q",
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k,
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v)
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}
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}
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// Call the mount helper, passing in the device file and saving output into a
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// buffer.
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cmd := exec.Command(
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bin,
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"-o", cfg.toOptionsString(),
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// Tell osxfuse-kext how large our buffer is. It must split
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// writes larger than this into multiple writes.
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//
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// OSXFUSE seems to ignore InitResponse.MaxWrite, and uses
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// this instead.
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"-o", "iosize="+strconv.FormatUint(buffer.MaxWriteSize, 10),
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// refers to fd passed in cmd.ExtraFiles
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"3",
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dir,
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)
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cmd.ExtraFiles = []*os.File{dev}
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cmd.Env = os.Environ()
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cmd.Env = append(cmd.Env, "MOUNT_FUSEFS_CALL_BY_LIB=")
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// TODO this is used for fs typenames etc, let app influence it
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cmd.Env = append(cmd.Env, "MOUNT_FUSEFS_DAEMON_PATH="+bin)
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var buf bytes.Buffer
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cmd.Stdout = &buf
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cmd.Stderr = &buf
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err = cmd.Start()
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if err != nil {
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return
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}
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// In the background, wait for the command to complete.
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go func() {
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err := cmd.Wait()
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if err != nil {
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if buf.Len() > 0 {
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output := buf.Bytes()
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output = bytes.TrimRight(output, "\n")
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err = fmt.Errorf("%v: %s", err, output)
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}
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}
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ready <- err
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}()
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return
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}
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|
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// Begin the process of mounting at the given directory, returning a connection
|
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// to the kernel. Mounting continues in the background, and is complete when an
|
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// error is written to the supplied channel. The file system may need to
|
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// service the connection in order for mounting to complete.
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func mount(
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dir string,
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cfg *MountConfig,
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ready chan<- error) (dev *os.File, err error) {
|
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// Open the device.
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dev, err = openOSXFUSEDev()
|
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// Special case: we may need to explicitly load osxfuse. Load it, then try
|
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// again.
|
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if err == errNotLoaded {
|
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err = loadOSXFUSE()
|
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if err != nil {
|
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err = fmt.Errorf("loadOSXFUSE: %v", err)
|
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return
|
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}
|
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|
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dev, err = openOSXFUSEDev()
|
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}
|
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|
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// Propagate errors.
|
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if err != nil {
|
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err = fmt.Errorf("openOSXFUSEDev: %v", err)
|
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return
|
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}
|
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|
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// Call the mount binary with the device.
|
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err = callMount(dir, cfg, dev, ready)
|
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if err != nil {
|
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dev.Close()
|
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err = fmt.Errorf("callMount: %v", err)
|
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return
|
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}
|
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|
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return
|
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}
|
|
@ -16,10 +16,6 @@ package fuse
|
|||
|
||||
import (
|
||||
"fmt"
|
||||
"log"
|
||||
"runtime"
|
||||
|
||||
"github.com/jacobsa/fuse/internal/fuseshim"
|
||||
|
||||
"golang.org/x/net/context"
|
||||
)
|
||||
|
@ -63,129 +59,6 @@ func (mfs *MountedFileSystem) Join(ctx context.Context) error {
|
|||
}
|
||||
}
|
||||
|
||||
// Optional configuration accepted by Mount.
|
||||
type MountConfig struct {
|
||||
// The context from which every op read from the connetion by the sever
|
||||
// should inherit. If nil, context.Background() will be used.
|
||||
OpContext context.Context
|
||||
|
||||
// If non-empty, the name of the file system as displayed by e.g. `mount`.
|
||||
// This is important because the `umount` command requires root privileges if
|
||||
// it doesn't agree with /etc/fstab.
|
||||
FSName string
|
||||
|
||||
// Mount the file system in read-only mode. File modes will appear as normal,
|
||||
// but opening a file for writing and metadata operations like chmod,
|
||||
// chtimes, etc. will fail.
|
||||
ReadOnly bool
|
||||
|
||||
// A logger to use for logging errors. All errors are logged, with the
|
||||
// exception of a few blacklisted errors that are expected. If nil, no error
|
||||
// logging is performed.
|
||||
ErrorLogger *log.Logger
|
||||
|
||||
// A logger to use for logging debug information. If nil, no debug logging is
|
||||
// performed.
|
||||
DebugLogger *log.Logger
|
||||
|
||||
// OS X only.
|
||||
//
|
||||
// Normally on OS X we mount with the novncache option
|
||||
// (cf. http://goo.gl/1pTjuk), which disables entry caching in the kernel.
|
||||
// This is because osxfuse does not honor the entry expiration values we
|
||||
// return to it, instead caching potentially forever (cf.
|
||||
// http://goo.gl/8yR0Ie), and it is probably better to fail to cache than to
|
||||
// cache for too long, since the latter is more likely to hide consistency
|
||||
// bugs that are difficult to detect and diagnose.
|
||||
//
|
||||
// This field disables the use of novncache, restoring entry caching. Beware:
|
||||
// the value of ChildInodeEntry.EntryExpiration is ignored by the kernel, and
|
||||
// entries will be cached for an arbitrarily long time.
|
||||
EnableVnodeCaching bool
|
||||
|
||||
// Additional key=value options to pass unadulterated to the underlying mount
|
||||
// command. See `man 8 mount`, the fuse documentation, etc. for
|
||||
// system-specific information.
|
||||
//
|
||||
// For expert use only! May invalidate other guarantees made in the
|
||||
// documentation for this package.
|
||||
Options map[string]string
|
||||
}
|
||||
|
||||
// Convert to mount options to be passed to package fuseshim.
|
||||
func (c *MountConfig) bazilfuseOptions() (opts []fuseshim.MountOption) {
|
||||
isDarwin := runtime.GOOS == "darwin"
|
||||
|
||||
// Enable permissions checking in the kernel. See the comments on
|
||||
// InodeAttributes.Mode.
|
||||
opts = append(opts, fuseshim.SetOption("default_permissions", ""))
|
||||
|
||||
// HACK(jacobsa): Work around what appears to be a bug in systemd v219, as
|
||||
// shipped in Ubuntu 15.04, where it automatically unmounts any file system
|
||||
// that doesn't set an explicit name.
|
||||
//
|
||||
// When Ubuntu contains systemd v220, this workaround should be removed and
|
||||
// the systemd bug reopened if the problem persists.
|
||||
//
|
||||
// Cf. https://github.com/bazil/fuse/issues/89
|
||||
// Cf. https://bugs.freedesktop.org/show_bug.cgi?id=90907
|
||||
fsname := c.FSName
|
||||
if runtime.GOOS == "linux" && fsname == "" {
|
||||
fsname = "some_fuse_file_system"
|
||||
}
|
||||
|
||||
// Special file system name?
|
||||
if fsname != "" {
|
||||
opts = append(opts, fuseshim.FSName(fsname))
|
||||
}
|
||||
|
||||
// Read only?
|
||||
if c.ReadOnly {
|
||||
opts = append(opts, fuseshim.ReadOnly())
|
||||
}
|
||||
|
||||
// OS X: set novncache when appropriate.
|
||||
if isDarwin && !c.EnableVnodeCaching {
|
||||
opts = append(opts, fuseshim.SetOption("novncache", ""))
|
||||
}
|
||||
|
||||
// OS X: disable the use of "Apple Double" (._foo and .DS_Store) files, which
|
||||
// just add noise to debug output and can have significant cost on
|
||||
// network-based file systems.
|
||||
//
|
||||
// Cf. https://github.com/osxfuse/osxfuse/wiki/Mount-options
|
||||
if isDarwin {
|
||||
opts = append(opts, fuseshim.SetOption("noappledouble", ""))
|
||||
}
|
||||
|
||||
// Ask the Linux kernel for larger read requests.
|
||||
//
|
||||
// As of 2015-03-26, the behavior in the kernel is:
|
||||
//
|
||||
// * (http://goo.gl/bQ1f1i, http://goo.gl/HwBrR6) Set the local variable
|
||||
// ra_pages to be init_response->max_readahead divided by the page size.
|
||||
//
|
||||
// * (http://goo.gl/gcIsSh, http://goo.gl/LKV2vA) Set
|
||||
// backing_dev_info::ra_pages to the min of that value and what was sent
|
||||
// in the request's max_readahead field.
|
||||
//
|
||||
// * (http://goo.gl/u2SqzH) Use backing_dev_info::ra_pages when deciding
|
||||
// how much to read ahead.
|
||||
//
|
||||
// * (http://goo.gl/JnhbdL) Don't read ahead at all if that field is zero.
|
||||
//
|
||||
// Reading a page at a time is a drag. Ask for a larger size.
|
||||
const maxReadahead = 1 << 20
|
||||
opts = append(opts, fuseshim.MaxReadahead(maxReadahead))
|
||||
|
||||
// Last but not least: other user-supplied options.
|
||||
for k, v := range c.Options {
|
||||
opts = append(opts, fuseshim.SetOption(k, v))
|
||||
}
|
||||
|
||||
return
|
||||
}
|
||||
|
||||
// Attempt to mount a file system on the given directory, using the supplied
|
||||
// Server to serve connection requests. This function blocks until the file
|
||||
// system is successfully mounted.
|
||||
|
@ -199,10 +72,11 @@ func Mount(
|
|||
joinStatusAvailable: make(chan struct{}),
|
||||
}
|
||||
|
||||
// Open a fuseshim connection.
|
||||
bfConn, err := fuseshim.Mount(mfs.dir, config.bazilfuseOptions()...)
|
||||
// Begin the mounting process, which will continue in the background.
|
||||
ready := make(chan error, 1)
|
||||
dev, err := mount(dir, config, ready)
|
||||
if err != nil {
|
||||
err = fmt.Errorf("fuseshim.Mount: %v", err)
|
||||
err = fmt.Errorf("mount: %v", err)
|
||||
return
|
||||
}
|
||||
|
||||
|
@ -212,15 +86,14 @@ func Mount(
|
|||
opContext = context.Background()
|
||||
}
|
||||
|
||||
// Create our own Connection object wrapping it.
|
||||
// Create a Connection object wrapping the device.
|
||||
connection, err := newConnection(
|
||||
opContext,
|
||||
config.DebugLogger,
|
||||
config.ErrorLogger,
|
||||
bfConn)
|
||||
dev)
|
||||
|
||||
if err != nil {
|
||||
bfConn.Close()
|
||||
err = fmt.Errorf("newConnection: %v", err)
|
||||
return
|
||||
}
|
||||
|
@ -232,9 +105,9 @@ func Mount(
|
|||
close(mfs.joinStatusAvailable)
|
||||
}()
|
||||
|
||||
// Wait for the connection to say it is ready.
|
||||
if err = connection.waitForReady(); err != nil {
|
||||
err = fmt.Errorf("WaitForReady: %v", err)
|
||||
// Wait for the mount process to complete.
|
||||
if err = <-ready; err != nil {
|
||||
err = fmt.Errorf("mount (background): %v", err)
|
||||
return
|
||||
}
|
||||
|
||||
|
|
Loading…
Reference in New Issue