Add support for device special files to VFS2 tmpfs.
PiperOrigin-RevId: 291471892
This commit is contained in:
parent
878bda6e19
commit
18a7e1309d
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@ -20,6 +20,7 @@ go_library(
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name = "tmpfs",
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srcs = [
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"dentry_list.go",
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"device_file.go",
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"directory.go",
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"filesystem.go",
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"named_pipe.go",
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@ -0,0 +1,39 @@
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// Copyright 2020 The gVisor Authors.
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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 tmpfs
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import (
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"gvisor.dev/gvisor/pkg/abi/linux"
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"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
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"gvisor.dev/gvisor/pkg/sentry/vfs"
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)
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type deviceFile struct {
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inode inode
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kind vfs.DeviceKind
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major uint32
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minor uint32
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}
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func (fs *filesystem) newDeviceFile(creds *auth.Credentials, mode linux.FileMode, kind vfs.DeviceKind, major, minor uint32) *inode {
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file := &deviceFile{
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kind: kind,
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major: major,
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minor: minor,
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}
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file.inode.init(file, fs, creds, mode)
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file.inode.nlink = 1 // from parent directory
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return &file.inode
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}
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@ -228,23 +228,26 @@ func (fs *filesystem) MkdirAt(ctx context.Context, rp *vfs.ResolvingPath, opts v
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// MknodAt implements vfs.FilesystemImpl.MknodAt.
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func (fs *filesystem) MknodAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.MknodOptions) error {
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return fs.doCreateAt(rp, false /* dir */, func(parent *dentry, name string) error {
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var childInode *inode
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switch opts.Mode.FileType() {
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case 0, linux.S_IFREG:
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child := fs.newDentry(fs.newRegularFile(rp.Credentials(), opts.Mode))
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parent.vfsd.InsertChild(&child.vfsd, name)
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parent.inode.impl.(*directory).childList.PushBack(child)
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return nil
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childInode = fs.newRegularFile(rp.Credentials(), opts.Mode)
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case linux.S_IFIFO:
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child := fs.newDentry(fs.newNamedPipe(rp.Credentials(), opts.Mode))
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parent.vfsd.InsertChild(&child.vfsd, name)
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parent.inode.impl.(*directory).childList.PushBack(child)
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return nil
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case linux.S_IFBLK, linux.S_IFCHR, linux.S_IFSOCK:
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childInode = fs.newNamedPipe(rp.Credentials(), opts.Mode)
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case linux.S_IFBLK:
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childInode = fs.newDeviceFile(rp.Credentials(), opts.Mode, vfs.BlockDevice, opts.DevMajor, opts.DevMinor)
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case linux.S_IFCHR:
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childInode = fs.newDeviceFile(rp.Credentials(), opts.Mode, vfs.CharDevice, opts.DevMajor, opts.DevMinor)
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case linux.S_IFSOCK:
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// Not yet supported.
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return syserror.EPERM
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default:
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return syserror.EINVAL
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}
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child := fs.newDentry(childInode)
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parent.vfsd.InsertChild(&child.vfsd, name)
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parent.inode.impl.(*directory).childList.PushBack(child)
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return nil
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})
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}
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@ -264,7 +267,7 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf
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if err != nil {
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return nil, err
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}
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return d.open(ctx, rp, opts.Flags, false /* afterCreate */)
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return d.open(ctx, rp, &opts, false /* afterCreate */)
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}
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mustCreate := opts.Flags&linux.O_EXCL != 0
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@ -279,7 +282,7 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf
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if mustCreate {
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return nil, syserror.EEXIST
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}
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return start.open(ctx, rp, opts.Flags, false /* afterCreate */)
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return start.open(ctx, rp, &opts, false /* afterCreate */)
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}
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afterTrailingSymlink:
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parent, err := walkParentDirLocked(rp, start)
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@ -313,7 +316,7 @@ afterTrailingSymlink:
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child := fs.newDentry(fs.newRegularFile(rp.Credentials(), opts.Mode))
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parent.vfsd.InsertChild(&child.vfsd, name)
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parent.inode.impl.(*directory).childList.PushBack(child)
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return child.open(ctx, rp, opts.Flags, true)
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return child.open(ctx, rp, &opts, true)
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}
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if err != nil {
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return nil, err
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@ -327,11 +330,11 @@ afterTrailingSymlink:
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if mustCreate {
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return nil, syserror.EEXIST
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}
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return child.open(ctx, rp, opts.Flags, false)
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return child.open(ctx, rp, &opts, false)
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}
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func (d *dentry) open(ctx context.Context, rp *vfs.ResolvingPath, flags uint32, afterCreate bool) (*vfs.FileDescription, error) {
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ats := vfs.AccessTypesForOpenFlags(flags)
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func (d *dentry) open(ctx context.Context, rp *vfs.ResolvingPath, opts *vfs.OpenOptions, afterCreate bool) (*vfs.FileDescription, error) {
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ats := vfs.AccessTypesForOpenFlags(opts.Flags)
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if !afterCreate {
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if err := d.inode.checkPermissions(rp.Credentials(), ats, d.inode.isDir()); err != nil {
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return nil, err
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@ -340,10 +343,10 @@ func (d *dentry) open(ctx context.Context, rp *vfs.ResolvingPath, flags uint32,
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switch impl := d.inode.impl.(type) {
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case *regularFile:
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var fd regularFileFD
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if err := fd.vfsfd.Init(&fd, flags, rp.Mount(), &d.vfsd, &vfs.FileDescriptionOptions{}); err != nil {
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if err := fd.vfsfd.Init(&fd, opts.Flags, rp.Mount(), &d.vfsd, &vfs.FileDescriptionOptions{}); err != nil {
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return nil, err
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}
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if flags&linux.O_TRUNC != 0 {
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if opts.Flags&linux.O_TRUNC != 0 {
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impl.mu.Lock()
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impl.data.Truncate(0, impl.memFile)
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atomic.StoreUint64(&impl.size, 0)
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@ -356,7 +359,7 @@ func (d *dentry) open(ctx context.Context, rp *vfs.ResolvingPath, flags uint32,
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return nil, syserror.EISDIR
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}
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var fd directoryFD
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if err := fd.vfsfd.Init(&fd, flags, rp.Mount(), &d.vfsd, &vfs.FileDescriptionOptions{}); err != nil {
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if err := fd.vfsfd.Init(&fd, opts.Flags, rp.Mount(), &d.vfsd, &vfs.FileDescriptionOptions{}); err != nil {
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return nil, err
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}
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return &fd.vfsfd, nil
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@ -364,7 +367,9 @@ func (d *dentry) open(ctx context.Context, rp *vfs.ResolvingPath, flags uint32,
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// Can't open symlinks without O_PATH (which is unimplemented).
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return nil, syserror.ELOOP
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case *namedPipe:
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return newNamedPipeFD(ctx, impl, rp, &d.vfsd, flags)
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return newNamedPipeFD(ctx, impl, rp, &d.vfsd, opts.Flags)
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case *deviceFile:
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return rp.VirtualFilesystem().OpenDeviceSpecialFile(ctx, rp.Mount(), &d.vfsd, impl.kind, impl.major, impl.minor, opts)
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default:
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panic(fmt.Sprintf("unknown inode type: %T", d.inode.impl))
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}
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@ -149,6 +149,10 @@ type inode struct {
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ctime int64 // nanoseconds
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mtime int64 // nanoseconds
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// Only meaningful for device special files.
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rdevMajor uint32
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rdevMinor uint32
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impl interface{} // immutable
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}
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@ -269,6 +273,15 @@ func (i *inode) statTo(stat *linux.Statx) {
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stat.Blocks = allocatedBlocksForSize(stat.Size)
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case *namedPipe:
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stat.Mode |= linux.S_IFIFO
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case *deviceFile:
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switch impl.kind {
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case vfs.BlockDevice:
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stat.Mode |= linux.S_IFBLK
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case vfs.CharDevice:
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stat.Mode |= linux.S_IFCHR
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}
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stat.RdevMajor = impl.major
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stat.RdevMinor = impl.minor
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default:
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panic(fmt.Sprintf("unknown inode type: %T", i.impl))
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}
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@ -309,12 +322,8 @@ func (i *inode) setStat(stat linux.Statx) error {
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}
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case *directory:
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return syserror.EISDIR
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case *symlink:
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return syserror.EINVAL
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case *namedPipe:
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// Nothing.
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default:
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panic(fmt.Sprintf("unknown inode type: %T", i.impl))
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return syserror.EINVAL
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}
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}
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if mask&linux.STATX_ATIME != 0 {
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@ -353,13 +362,22 @@ func allocatedBlocksForSize(size uint64) uint64 {
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}
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func (i *inode) direntType() uint8 {
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switch i.impl.(type) {
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switch impl := i.impl.(type) {
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case *regularFile:
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return linux.DT_REG
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case *directory:
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return linux.DT_DIR
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case *symlink:
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return linux.DT_LNK
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case *deviceFile:
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switch impl.kind {
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case vfs.BlockDevice:
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return linux.DT_BLK
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case vfs.CharDevice:
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return linux.DT_CHR
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default:
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panic(fmt.Sprintf("unknown vfs.DeviceKind: %v", impl.kind))
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}
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default:
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panic(fmt.Sprintf("unknown inode type: %T", i.impl))
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}
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