255 lines
6.8 KiB
Go
255 lines
6.8 KiB
Go
// 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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"syscall"
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"unsafe"
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"github.com/jacobsa/fuse/fuseops"
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"github.com/jacobsa/fuse/internal/buffer"
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"github.com/jacobsa/fuse/internal/fusekernel"
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)
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// Return the response that should be sent to the kernel. If the op requires no
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// response, return a nil response.
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func kernelResponse(
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fuseID uint64,
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op fuseops.Op,
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opErr error,
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protocol fusekernel.Protocol) (msg []byte) {
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// If the user replied with an error, create room enough just for the result
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// header and fill it in with an error. Otherwise create an appropriate
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// response.
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var b *buffer.OutMessage
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if opErr != nil {
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b = buffer.NewOutMessage(0)
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if errno, ok := opErr.(syscall.Errno); ok {
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b.OutHeader().Error = -int32(errno)
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} else {
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b.OutHeader().Error = -int32(syscall.EIO)
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}
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} else {
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b = kernelResponseForOp(op, protocol)
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}
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msg = b.Bytes()
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// Fill in the rest of the header.
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h := b.OutHeader()
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h.Unique = fuseID
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h.Len = uint32(len(msg))
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return
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}
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// Like kernelResponse, but assumes the user replied with a nil error to the
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// op.
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func kernelResponseForOp(
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op fuseops.Op,
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protocol fusekernel.Protocol) (b *buffer.OutMessage) {
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// Create the appropriate output message
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switch o := op.(type) {
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case *fuseops.LookUpInodeOp:
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size := fusekernel.EntryOutSize(protocol)
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b = buffer.NewOutMessage(size)
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out := (*fusekernel.EntryOut)(b.Grow(size))
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convertChildInodeEntry(&o.Entry, out)
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case *fuseops.GetInodeAttributesOp:
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size := fusekernel.AttrOutSize(protocol)
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b = buffer.NewOutMessage(size)
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out := (*fusekernel.AttrOut)(b.Grow(size))
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out.AttrValid, out.AttrValidNsec = convertExpirationTime(o.AttributesExpiration)
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convertAttributes(o.Inode, &o.Attributes, &out.Attr)
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case *fuseops.SetInodeAttributesOp:
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size := fusekernel.AttrOutSize(protocol)
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b = buffer.NewOutMessage(size)
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out := (*fusekernel.AttrOut)(b.Grow(size))
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out.AttrValid, out.AttrValidNsec = convertExpirationTime(o.AttributesExpiration)
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convertAttributes(o.Inode, &o.Attributes, &out.Attr)
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case *fuseops.ForgetInodeOp:
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// No response.
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case *fuseops.MkDirOp:
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size := fusekernel.EntryOutSize(protocol)
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b = buffer.NewOutMessage(size)
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out := (*fusekernel.EntryOut)(b.Grow(size))
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convertChildInodeEntry(&o.Entry, out)
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case *fuseops.CreateFileOp:
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eSize := fusekernel.EntryOutSize(protocol)
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b = buffer.NewOutMessage(eSize + unsafe.Sizeof(fusekernel.OpenOut{}))
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e := (*fusekernel.EntryOut)(b.Grow(eSize))
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convertChildInodeEntry(&o.Entry, e)
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oo := (*fusekernel.OpenOut)(b.Grow(unsafe.Sizeof(fusekernel.OpenOut{})))
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oo.Fh = uint64(o.Handle)
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case *fuseops.CreateSymlinkOp:
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size := fusekernel.EntryOutSize(protocol)
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b = buffer.NewOutMessage(size)
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out := (*fusekernel.EntryOut)(b.Grow(size))
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convertChildInodeEntry(&o.Entry, out)
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case *fuseops.RenameOp:
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b = buffer.NewOutMessage(0)
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case *fuseops.RmDirOp:
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b = buffer.NewOutMessage(0)
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case *fuseops.UnlinkOp:
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b = buffer.NewOutMessage(0)
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case *fuseops.OpenDirOp:
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b = buffer.NewOutMessage(unsafe.Sizeof(fusekernel.OpenOut{}))
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out := (*fusekernel.OpenOut)(b.Grow(unsafe.Sizeof(fusekernel.OpenOut{})))
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out.Fh = uint64(o.Handle)
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case *fuseops.ReadDirOp:
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b = buffer.NewOutMessage(uintptr(len(o.Data)))
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b.Append(o.Data)
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case *fuseops.ReleaseDirHandleOp:
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b = buffer.NewOutMessage(0)
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case *fuseops.OpenFileOp:
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b = buffer.NewOutMessage(unsafe.Sizeof(fusekernel.OpenOut{}))
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out := (*fusekernel.OpenOut)(b.Grow(unsafe.Sizeof(fusekernel.OpenOut{})))
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out.Fh = uint64(o.Handle)
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case *fuseops.ReadFileOp:
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b = buffer.NewOutMessage(uintptr(len(o.Data)))
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b.Append(o.Data)
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case *fuseops.WriteFileOp:
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b = buffer.NewOutMessage(unsafe.Sizeof(fusekernel.WriteOut{}))
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out := (*fusekernel.WriteOut)(b.Grow(unsafe.Sizeof(fusekernel.WriteOut{})))
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out.Size = uint32(len(o.Data))
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case *fuseops.SyncFileOp:
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b = buffer.NewOutMessage(0)
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case *fuseops.FlushFileOp:
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b = buffer.NewOutMessage(0)
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case *fuseops.ReleaseFileHandleOp:
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b = buffer.NewOutMessage(0)
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case *fuseops.ReadSymlinkOp:
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b = buffer.NewOutMessage(uintptr(len(o.Target)))
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b.AppendString(o.Target)
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case *internalStatFSOp:
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b = buffer.NewOutMessage(unsafe.Sizeof(fusekernel.StatfsOut{}))
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b.Grow(unsafe.Sizeof(fusekernel.StatfsOut{}))
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case *internalInterruptOp:
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// No response.
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case *internalInitOp:
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b = buffer.NewOutMessage(unsafe.Sizeof(fusekernel.InitOut{}))
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out := (*fusekernel.InitOut)(b.Grow(unsafe.Sizeof(fusekernel.InitOut{})))
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out.Major = o.Library.Major
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out.Minor = o.Library.Minor
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out.MaxReadahead = o.MaxReadahead
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out.Flags = uint32(o.Flags)
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out.MaxWrite = o.MaxWrite
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default:
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panic(fmt.Sprintf("Unknown op: %#v", op))
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}
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return
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}
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////////////////////////////////////////////////////////////////////////
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// Internal
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////////////////////////////////////////////////////////////////////////
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// A sentinel used for unknown ops. The user is expected to respond with a
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// non-nil error.
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type unknownOp struct {
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opCode uint32
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inode fuseops.InodeID
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}
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func (o *unknownOp) ShortDesc() (desc string) {
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desc = fmt.Sprintf("<opcode %d>(inode=%v)", o.opCode, o.inode)
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return
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}
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func (o *unknownOp) DebugString() string {
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return o.ShortDesc()
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}
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// Common implementation for our "internal" ops that don't need to be pretty.
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type internalOp struct {
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}
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func (o *internalOp) ShortDesc() string { return "<internalOp>" }
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func (o *internalOp) DebugString() string { return "<internalOp>" }
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type internalStatFSOp struct {
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internalOp
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}
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func (o *internalStatFSOp) kernelResponse() (b buffer.OutMessage) {
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b = buffer.NewOutMessage(unsafe.Sizeof(fusekernel.StatfsOut{}))
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b.Grow(unsafe.Sizeof(fusekernel.StatfsOut{}))
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return
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}
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type internalInterruptOp struct {
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internalOp
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FuseID uint64
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}
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func (o *internalInterruptOp) kernelResponse() (b buffer.OutMessage) {
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panic("Shouldn't get here.")
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}
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type internalInitOp struct {
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internalOp
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// In
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Kernel fusekernel.Protocol
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// Out
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Library fusekernel.Protocol
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MaxReadahead uint32
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Flags fusekernel.InitFlags
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MaxWrite uint32
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}
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func (o *internalInitOp) kernelResponse() (b buffer.OutMessage) {
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b = buffer.NewOutMessage(unsafe.Sizeof(fusekernel.InitOut{}))
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out := (*fusekernel.InitOut)(b.Grow(unsafe.Sizeof(fusekernel.InitOut{})))
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out.Major = o.Library.Major
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out.Minor = o.Library.Minor
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out.MaxReadahead = o.MaxReadahead
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out.Flags = uint32(o.Flags)
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out.MaxWrite = o.MaxWrite
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return
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}
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