/
inode.go
852 lines (769 loc) · 26.3 KB
/
inode.go
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// Copyright 2022 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package fuse
import (
"fmt"
"sync"
gotime "time"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/atomicbitops"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/errors/linuxerr"
"gvisor.dev/gvisor/pkg/hostarch"
"gvisor.dev/gvisor/pkg/marshal"
"gvisor.dev/gvisor/pkg/marshal/primitive"
"gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs"
"gvisor.dev/gvisor/pkg/sentry/kernel"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/sentry/kernel/time"
"gvisor.dev/gvisor/pkg/sentry/vfs"
)
// +stateify savable
type fileHandle struct {
new bool
handle uint64
flags uint32
}
// inode implements kernfs.Inode.
//
// +stateify savable
type inode struct {
inodeRefs
kernfs.InodeNotAnonymous
kernfs.InodeNotSymlink
kernfs.InodeWatches
kernfs.OrderedChildren
kernfs.CachedMappable
// the owning filesystem. fs is immutable.
fs *filesystem
// nodeID is a unique id which identifies the inode between userspace
// and the sentry. Immutable.
nodeID uint64
// entryTime is the time at which the entry becomes invalid.
entryTime time.Time
// attrVersion is the version of the last attribute change.
attrVersion atomicbitops.Uint64
// attrTime is the time at which the attributes become invalid.
attrTime time.Time
// link is result of following a symbolic link.
link string
// fh caches the file handle returned by the server from a FUSE_CREATE request
// so we don't have to send a separate FUSE_OPEN request.
fh fileHandle
locks vfs.FileLocks
watches vfs.Watches
// attrMu protects the attributes of this inode.
attrMu sync.Mutex `state:"nosave"`
// +checklocks:attrMu
ino atomicbitops.Uint64 // Stat data, not accessed for path walking.
// +checklocks:attrMu
uid atomicbitops.Uint32 // auth.KUID, but stored as raw uint32 for sync/atomic.
// +checklocks:attrMu
gid atomicbitops.Uint32 // auth.KGID, but...
// +checklocks:attrMu
mode atomicbitops.Uint32 // File type and mode.
// Timestamps in nanoseconds from the unix epoch.
// +checklocks:attrMu
atime atomicbitops.Int64
// +checklocks:attrMu
mtime atomicbitops.Int64
// +checklocks:attrMu
ctime atomicbitops.Int64
// +checklocks:attrMu
size atomicbitops.Uint64
// nlink counts the number of hard links to this inode. It's updated and
// accessed used atomic operations but not protected by attrMu.
nlink atomicbitops.Uint32
// +checklocks:attrMu
blockSize atomicbitops.Uint32 // 0 if unknown.
}
func blockerFromContext(ctx context.Context) context.Blocker {
kernelTask := kernel.TaskFromContext(ctx)
if kernelTask == nil {
return ctx
}
return kernelTask
}
func pidFromContext(ctx context.Context) uint32 {
kernelTask := kernel.TaskFromContext(ctx)
if kernelTask == nil {
return 0
}
return uint32(kernelTask.ThreadID())
}
func umaskFromContext(ctx context.Context) uint32 {
kernelTask := kernel.TaskFromContext(ctx)
umask := uint32(0)
if kernelTask != nil {
umask = uint32(kernelTask.FSContext().Umask())
}
return umask
}
func (i *inode) Mode() linux.FileMode {
i.attrMu.Lock()
defer i.attrMu.Unlock()
return i.filemode()
}
func (i *inode) UID() auth.KUID {
i.attrMu.Lock()
defer i.attrMu.Unlock()
return auth.KUID(i.uid.Load())
}
func (i *inode) GID() auth.KGID {
i.attrMu.Lock()
defer i.attrMu.Unlock()
return auth.KGID(i.gid.Load())
}
// +checklocks:i.attrMu
func (i *inode) filemode() linux.FileMode {
return linux.FileMode(i.mode.Load())
}
// touchCMTime updates the ctime and mtime attributes to be the current time.
//
// +checklocks:i.attrMu
func (i *inode) touchCMtime() {
now := i.fs.clock.Now().Nanoseconds()
i.mtime.Store(now)
i.ctime.Store(now)
}
// touchAtime updates the atime attribute to be the current time.
//
// +checklocks:i.attrMu
func (i *inode) touchAtime() {
i.atime.Store(i.fs.clock.Now().Nanoseconds())
}
// +checklocks:i.attrMu
func (i *inode) init(creds *auth.Credentials, devMajor, devMinor uint32, nodeid uint64, mode linux.FileMode, nlink uint32) {
if mode.FileType() == 0 {
panic(fmt.Sprintf("No file type specified in 'mode' for InodeAttrs.Init(): mode=0%o", mode))
}
i.nodeID = nodeid
i.ino.Store(nodeid)
i.mode.Store(uint32(mode))
i.uid.Store(uint32(creds.EffectiveKUID))
i.gid.Store(uint32(creds.EffectiveKGID))
i.nlink.Store(nlink)
i.blockSize.Store(hostarch.PageSize)
now := i.fs.clock.Now().Nanoseconds()
i.atime.Store(now)
i.mtime.Store(now)
i.ctime.Store(now)
}
func (i *inode) updateEntryTime(entrySec, entryNSec int64) {
entryTime := time.FromTimespec(linux.Timespec{Sec: entrySec, Nsec: entryNSec})
i.entryTime = i.fs.clock.Now().AddTime(entryTime)
}
// CheckPermissions implements kernfs.Inode.CheckPermissions.
func (i *inode) CheckPermissions(ctx context.Context, creds *auth.Credentials, ats vfs.AccessTypes) error {
// Since FUSE operations are ultimately backed by a userspace process (the
// fuse daemon), allowing a process to call into fusefs grants the daemon
// ptrace-like capabilities over the calling process. Because of this, by
// default FUSE only allows the mount owner to interact with the
// filesystem. This explicitly excludes setuid/setgid processes.
//
// This behaviour can be overridden with the 'allow_other' mount option.
//
// See fs/fuse/dir.c:fuse_allow_current_process() in Linux.
if !i.fs.opts.allowOther {
if creds.RealKUID != i.fs.opts.uid ||
creds.EffectiveKUID != i.fs.opts.uid ||
creds.SavedKUID != i.fs.opts.uid ||
creds.RealKGID != i.fs.opts.gid ||
creds.EffectiveKGID != i.fs.opts.gid ||
creds.SavedKGID != i.fs.opts.gid {
return linuxerr.EACCES
}
}
// By default, fusefs delegates all permission checks to the server.
// However, standard unix permission checks can be enabled with the
// default_permissions mount option.
i.attrMu.Lock()
defer i.attrMu.Unlock()
refreshed := false
opts := vfs.StatOptions{Mask: linux.STATX_MODE | linux.STATX_UID | linux.STATX_GID}
if i.fs.opts.defaultPermissions || (ats.MayExec() && i.filemode().FileType() == linux.S_IFREG) {
if i.fs.clock.Now().After(i.attrTime) {
refreshed = true
if _, err := i.getAttr(ctx, i.fs.VFSFilesystem(), opts, 0, 0); err != nil {
return err
}
}
}
if i.fs.opts.defaultPermissions || (ats.MayExec() && i.filemode().FileType() == linux.S_IFREG) {
err := vfs.GenericCheckPermissions(creds, ats, linux.FileMode(i.mode.Load()), auth.KUID(i.uid.Load()), auth.KGID(i.gid.Load()))
if linuxerr.Equals(linuxerr.EACCES, err) && !refreshed {
if _, err := i.getAttr(ctx, i.fs.VFSFilesystem(), opts, 0, 0); err != nil {
return err
}
return vfs.GenericCheckPermissions(creds, ats, linux.FileMode(i.mode.Load()), auth.KUID(i.uid.Load()), auth.KGID(i.gid.Load()))
}
return err
} else if ats.MayRead() || ats.MayWrite() || ats.MayExec() {
in := linux.FUSEAccessIn{Mask: uint32(ats)}
req := i.fs.conn.NewRequest(auth.CredentialsFromContext(ctx), pidFromContext(ctx), i.nodeID, linux.FUSE_ACCESS, &in)
res, err := i.fs.conn.Call(ctx, req)
if err != nil {
return err
}
return res.Error()
}
return nil
}
// Open implements kernfs.Inode.Open.
func (i *inode) Open(ctx context.Context, rp *vfs.ResolvingPath, d *kernfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
opts.Flags &= linux.O_ACCMODE | linux.O_CREAT | linux.O_EXCL | linux.O_TRUNC |
linux.O_DIRECTORY | linux.O_NOFOLLOW | linux.O_NONBLOCK | linux.O_NOCTTY |
linux.O_APPEND | linux.O_DIRECT
i.attrMu.Lock()
defer i.attrMu.Unlock()
if opts.Flags&linux.O_LARGEFILE == 0 && i.size.Load() > linux.MAX_NON_LFS {
return nil, linuxerr.EOVERFLOW
}
var (
fd *fileDescription
fdImpl vfs.FileDescriptionImpl
opcode linux.FUSEOpcode
)
switch i.filemode().FileType() {
case linux.S_IFREG:
regularFD := ®ularFileFD{}
fd = &(regularFD.fileDescription)
fdImpl = regularFD
opcode = linux.FUSE_OPEN
case linux.S_IFDIR:
if opts.Flags&linux.O_CREAT != 0 {
return nil, linuxerr.EISDIR
}
if ats := vfs.AccessTypesForOpenFlags(&opts); ats.MayWrite() {
return nil, linuxerr.EISDIR
}
if opts.Flags&linux.O_DIRECT != 0 {
return nil, linuxerr.EINVAL
}
directoryFD := &directoryFD{}
fd = &(directoryFD.fileDescription)
fdImpl = directoryFD
opcode = linux.FUSE_OPENDIR
case linux.S_IFLNK:
return nil, linuxerr.ELOOP
}
fd.LockFD.Init(&i.locks)
// FOPEN_KEEP_CACHE is the default flag for noOpen.
fd.OpenFlag = linux.FOPEN_KEEP_CACHE
truncateRegFile := opts.Flags&linux.O_TRUNC != 0 && i.filemode().FileType() == linux.S_IFREG
if truncateRegFile && (i.fh.new || !i.fs.conn.atomicOTrunc) {
// If the regular file needs to be truncated, but the connection doesn't
// support O_TRUNC or if we are optimizing away the Open RPC, then manually
// truncate the file *before* Open. As per libfuse, "If [atomic O_TRUNC is]
// disabled, and an application specifies O_TRUNC, fuse first calls
// truncate() and then open() with O_TRUNC filtered out.".
opts := vfs.SetStatOptions{Stat: linux.Statx{Size: 0, Mask: linux.STATX_SIZE}}
if err := i.setAttr(ctx, i.fs.VFSFilesystem(), auth.CredentialsFromContext(ctx), opts, fhOptions{useFh: false}); err != nil {
return nil, err
}
}
if i.fh.new {
fd.OpenFlag = i.fh.flags
fd.Fh = i.fh.handle
i.fh.new = false
// Only send an open request when the FUSE server supports open or is
// opening a directory.
} else if !i.fs.conn.noOpen || i.filemode().IsDir() {
in := linux.FUSEOpenIn{Flags: opts.Flags & ^uint32(linux.O_CREAT|linux.O_EXCL|linux.O_NOCTTY)}
// Clear O_TRUNC if the server doesn't support it.
if !i.fs.conn.atomicOTrunc {
in.Flags &= ^uint32(linux.O_TRUNC)
}
req := i.fs.conn.NewRequest(auth.CredentialsFromContext(ctx), pidFromContext(ctx), i.nodeID, opcode, &in)
res, err := i.fs.conn.Call(ctx, req)
if err != nil {
return nil, err
}
if err := res.Error(); err != nil {
if linuxerr.Equals(linuxerr.ENOSYS, err) && !i.filemode().IsDir() {
i.fs.conn.noOpen = true
} else {
return nil, err
}
} else {
out := linux.FUSEOpenOut{}
if err := res.UnmarshalPayload(&out); err != nil {
return nil, err
}
fd.OpenFlag = out.OpenFlag
fd.Fh = out.Fh
// Open was successful. Update inode's size if atomicOTrunc && O_TRUNC.
if truncateRegFile && i.fs.conn.atomicOTrunc {
i.fs.conn.mu.Lock()
i.attrVersion.Store(i.fs.conn.attributeVersion.Add(1))
i.fs.conn.mu.Unlock()
i.size.Store(0)
i.touchCMtime()
}
}
}
if i.filemode().IsDir() {
fd.OpenFlag &= ^uint32(linux.FOPEN_DIRECT_IO)
}
// TODO(gvisor.dev/issue/3234): invalidate mmap after implemented it for FUSE Inode
fd.DirectIO = fd.OpenFlag&linux.FOPEN_DIRECT_IO != 0
fdOptions := &vfs.FileDescriptionOptions{}
if fd.OpenFlag&linux.FOPEN_NONSEEKABLE != 0 {
fdOptions.DenyPRead = true
fdOptions.DenyPWrite = true
fd.Nonseekable = true
}
if err := fd.vfsfd.Init(fdImpl, opts.Flags, rp.Mount(), d.VFSDentry(), fdOptions); err != nil {
return nil, err
}
return &fd.vfsfd, nil
}
func (i *inode) Valid(ctx context.Context) bool {
return i.entryTime.After(i.fs.clock.Now())
}
// Lookup implements kernfs.Inode.Lookup.
func (i *inode) Lookup(ctx context.Context, name string) (kernfs.Inode, error) {
in := linux.FUSELookupIn{Name: linux.CString(name)}
return i.newEntry(ctx, name, 0, linux.FUSE_LOOKUP, &in)
}
// Keep implements kernfs.Inode.Keep.
func (i *inode) Keep() bool {
// Return true so that kernfs keeps the new dentry pointing to this
// inode in the dentry tree. This is needed because inodes created via
// Lookup are not temporary. They might refer to existing files on server
// that can be Unlink'd/Rmdir'd.
return true
}
// IterDirents implements kernfs.Inode.IterDirents.
func (*inode) IterDirents(ctx context.Context, mnt *vfs.Mount, callback vfs.IterDirentsCallback, offset, relOffset int64) (int64, error) {
return offset, nil
}
// NewFile implements kernfs.Inode.NewFile.
func (i *inode) NewFile(ctx context.Context, name string, opts vfs.OpenOptions) (kernfs.Inode, error) {
opts.Flags &= linux.O_ACCMODE | linux.O_CREAT | linux.O_EXCL | linux.O_TRUNC |
linux.O_DIRECTORY | linux.O_NOFOLLOW | linux.O_NONBLOCK | linux.O_NOCTTY
in := linux.FUSECreateIn{
CreateMeta: linux.FUSECreateMeta{
Flags: opts.Flags,
Mode: uint32(opts.Mode) | linux.S_IFREG,
Umask: umaskFromContext(ctx),
},
Name: linux.CString(name),
}
return i.newEntry(ctx, name, linux.S_IFREG, linux.FUSE_CREATE, &in)
}
// NewNode implements kernfs.Inode.NewNode.
func (i *inode) NewNode(ctx context.Context, name string, opts vfs.MknodOptions) (kernfs.Inode, error) {
in := linux.FUSEMknodIn{
MknodMeta: linux.FUSEMknodMeta{
Mode: uint32(opts.Mode),
Rdev: linux.MakeDeviceID(uint16(opts.DevMajor), opts.DevMinor),
Umask: umaskFromContext(ctx),
},
Name: linux.CString(name),
}
return i.newEntry(ctx, name, opts.Mode.FileType(), linux.FUSE_MKNOD, &in)
}
// NewSymlink implements kernfs.Inode.NewSymlink.
func (i *inode) NewSymlink(ctx context.Context, name, target string) (kernfs.Inode, error) {
in := linux.FUSESymlinkIn{
Name: linux.CString(name),
Target: linux.CString(target),
}
return i.newEntry(ctx, name, linux.S_IFLNK, linux.FUSE_SYMLINK, &in)
}
// NewLink implements kernfs.Inode.NewLink.
func (i *inode) NewLink(ctx context.Context, name string, target kernfs.Inode) (kernfs.Inode, error) {
targetInode := target.(*inode)
in := linux.FUSELinkIn{
OldNodeID: primitive.Uint64(targetInode.nodeID),
Name: linux.CString(name),
}
return i.newEntry(ctx, name, targetInode.Mode().FileType(), linux.FUSE_LINK, &in)
}
// Unlink implements kernfs.Inode.Unlink.
func (i *inode) Unlink(ctx context.Context, name string, child kernfs.Inode) error {
in := linux.FUSEUnlinkIn{Name: linux.CString(name)}
req := i.fs.conn.NewRequest(auth.CredentialsFromContext(ctx), pidFromContext(ctx), i.nodeID, linux.FUSE_UNLINK, &in)
res, err := i.fs.conn.Call(ctx, req)
if err != nil {
return err
}
// only return error, discard res.
return res.Error()
}
// NewDir implements kernfs.Inode.NewDir.
func (i *inode) NewDir(ctx context.Context, name string, opts vfs.MkdirOptions) (kernfs.Inode, error) {
in := linux.FUSEMkdirIn{
MkdirMeta: linux.FUSEMkdirMeta{
Mode: uint32(opts.Mode),
Umask: umaskFromContext(ctx),
},
Name: linux.CString(name),
}
return i.newEntry(ctx, name, linux.S_IFDIR, linux.FUSE_MKDIR, &in)
}
// RmDir implements kernfs.Inode.RmDir.
func (i *inode) RmDir(ctx context.Context, name string, child kernfs.Inode) error {
in := linux.FUSERmDirIn{Name: linux.CString(name)}
req := i.fs.conn.NewRequest(auth.CredentialsFromContext(ctx), pidFromContext(ctx), i.nodeID, linux.FUSE_RMDIR, &in)
res, err := i.fs.conn.Call(ctx, req)
if err != nil {
return err
}
return res.Error()
}
// Rename implements kernfs.Inode.Rename.
func (i *inode) Rename(ctx context.Context, oldname, newname string, child, dstDir kernfs.Inode) error {
dstDirInode := dstDir.(*inode)
in := linux.FUSERenameIn{
Newdir: primitive.Uint64(dstDirInode.nodeID),
Oldname: linux.CString(oldname),
Newname: linux.CString(newname),
}
req := i.fs.conn.NewRequest(auth.CredentialsFromContext(ctx), pidFromContext(ctx), i.nodeID, linux.FUSE_RENAME, &in)
res, err := i.fs.conn.Call(ctx, req)
if err != nil {
return err
}
return res.Error()
}
// newEntry calls FUSE server for entry creation and allocates corresponding
// entry according to response. Shared by FUSE_MKNOD, FUSE_MKDIR, FUSE_SYMLINK,
// FUSE_LINK and FUSE_LOOKUP.
func (i *inode) newEntry(ctx context.Context, name string, fileType linux.FileMode, opcode linux.FUSEOpcode, payload marshal.Marshallable) (kernfs.Inode, error) {
req := i.fs.conn.NewRequest(auth.CredentialsFromContext(ctx), pidFromContext(ctx), i.nodeID, opcode, payload)
res, err := i.fs.conn.Call(ctx, req)
if err != nil {
return nil, err
}
if err := res.Error(); err != nil {
return nil, err
}
out := linux.FUSECreateOut{}
if opcode == linux.FUSE_CREATE {
if err := res.UnmarshalPayload(&out); err != nil {
return nil, err
}
} else {
if err := res.UnmarshalPayload(&out.FUSEEntryOut); err != nil {
return nil, err
}
}
if opcode != linux.FUSE_LOOKUP && ((out.Attr.Mode&linux.S_IFMT)^uint32(fileType) != 0 || out.NodeID == 0 || out.NodeID == linux.FUSE_ROOT_ID) {
return nil, linuxerr.EIO
}
child := i.fs.newInode(ctx, out.NodeID, out.FUSEEntryOut)
if opcode == linux.FUSE_CREATE {
// File handler is returned by fuse server at a time of file create.
// Save it temporary in a created child, so Open could return it when invoked
// to be sure after fh is consumed reset 'isNewFh' flag of inode
childI, ok := child.(*inode)
if ok {
childI.fh.new = true
childI.fh.handle = out.FUSEOpenOut.Fh
childI.fh.flags = out.FUSEOpenOut.OpenFlag
}
}
return child, nil
}
// Getlink implements kernfs.Inode.Getlink.
func (i *inode) Getlink(ctx context.Context, mnt *vfs.Mount) (vfs.VirtualDentry, string, error) {
path, err := i.Readlink(ctx, mnt)
return vfs.VirtualDentry{}, path, err
}
// Readlink implements kernfs.Inode.Readlink.
func (i *inode) Readlink(ctx context.Context, mnt *vfs.Mount) (string, error) {
i.attrMu.Lock()
defer i.attrMu.Unlock()
if i.filemode().FileType()&linux.S_IFLNK == 0 {
return "", linuxerr.EINVAL
}
if len(i.link) == 0 {
req := i.fs.conn.NewRequest(auth.CredentialsFromContext(ctx), pidFromContext(ctx), i.nodeID, linux.FUSE_READLINK, &linux.FUSEEmptyIn{})
res, err := i.fs.conn.Call(ctx, req)
if err != nil {
return "", err
}
i.link = string(res.data[res.hdr.SizeBytes():])
if !mnt.Options().ReadOnly {
i.attrTime = time.ZeroTime
}
}
return i.link, nil
}
// getFUSEAttr returns a linux.FUSEAttr of this inode stored in local cache.
//
// +checklocks:i.attrMu
func (i *inode) getFUSEAttr() linux.FUSEAttr {
ns := gotime.Second.Nanoseconds()
return linux.FUSEAttr{
Ino: i.nodeID,
UID: i.uid.Load(),
GID: i.gid.Load(),
Size: i.size.Load(),
Mode: uint32(i.filemode()),
BlkSize: i.blockSize.Load(),
Atime: uint64(i.atime.Load() / ns),
Mtime: uint64(i.mtime.Load() / ns),
Ctime: uint64(i.ctime.Load() / ns),
AtimeNsec: uint32(i.atime.Load() % ns),
MtimeNsec: uint32(i.mtime.Load() % ns),
CtimeNsec: uint32(i.ctime.Load() % ns),
Nlink: i.nlink.Load(),
}
}
// statFromFUSEAttr makes attributes from linux.FUSEAttr to linux.Statx. The
// opts.Sync attribute is ignored since the synchronization is handled by the
// FUSE server.
func statFromFUSEAttr(attr linux.FUSEAttr, mask, devMinor uint32) linux.Statx {
var stat linux.Statx
stat.Blksize = attr.BlkSize
stat.DevMajor, stat.DevMinor = linux.UNNAMED_MAJOR, devMinor
rdevMajor, rdevMinor := linux.DecodeDeviceID(attr.Rdev)
stat.RdevMajor, stat.RdevMinor = uint32(rdevMajor), rdevMinor
if mask&linux.STATX_MODE != 0 {
stat.Mode = uint16(attr.Mode)
}
if mask&linux.STATX_NLINK != 0 {
stat.Nlink = attr.Nlink
}
if mask&linux.STATX_UID != 0 {
stat.UID = attr.UID
}
if mask&linux.STATX_GID != 0 {
stat.GID = attr.GID
}
if mask&linux.STATX_ATIME != 0 {
stat.Atime = linux.StatxTimestamp{
Sec: int64(attr.Atime),
Nsec: attr.AtimeNsec,
}
}
if mask&linux.STATX_MTIME != 0 {
stat.Mtime = linux.StatxTimestamp{
Sec: int64(attr.Mtime),
Nsec: attr.MtimeNsec,
}
}
if mask&linux.STATX_CTIME != 0 {
stat.Ctime = linux.StatxTimestamp{
Sec: int64(attr.Ctime),
Nsec: attr.CtimeNsec,
}
}
if mask&linux.STATX_INO != 0 {
stat.Ino = attr.Ino
}
if mask&linux.STATX_SIZE != 0 {
stat.Size = attr.Size
}
if mask&linux.STATX_BLOCKS != 0 {
stat.Blocks = attr.Blocks
}
return stat
}
// getAttr gets the attribute of this inode by issuing a FUSE_GETATTR request
// or read from local cache. It updates the corresponding attributes if
// necessary.
//
// +checklocks:i.attrMu
func (i *inode) getAttr(ctx context.Context, fs *vfs.Filesystem, opts vfs.StatOptions, flags uint32, fh uint64) (linux.FUSEAttr, error) {
// TODO(gvisor.dev/issue/3679): send the request only if
// - invalid local cache for fields specified in the opts.Mask
// - forced update
// - i.attributeTime expired
// If local cache is still valid, return local cache.
// Currently we always send a request,
// and we always set the metadata with the new result,
// unless attributeVersion has changed.
creds := auth.CredentialsFromContext(ctx)
in := linux.FUSEGetAttrIn{
GetAttrFlags: flags,
Fh: fh,
}
req := i.fs.conn.NewRequest(creds, pidFromContext(ctx), i.nodeID, linux.FUSE_GETATTR, &in)
res, err := i.fs.conn.Call(ctx, req)
if err != nil {
return linux.FUSEAttr{}, err
}
if err := res.Error(); err != nil {
return linux.FUSEAttr{}, err
}
var out linux.FUSEAttrOut
if err := res.UnmarshalPayload(&out); err != nil {
return linux.FUSEAttr{}, err
}
// Local version is newer, return the local one.
i.fs.conn.mu.Lock()
attributeVersion := i.fs.conn.attributeVersion.Load()
if attributeVersion != 0 && i.attrVersion.Load() > attributeVersion {
i.fs.conn.mu.Unlock()
return i.getFUSEAttr(), nil
}
i.fs.conn.mu.Unlock()
i.updateAttrs(out.Attr, int64(out.AttrValid), int64(out.AttrValidNsec))
return out.Attr, nil
}
// reviseAttr attempts to update the attributes for internal purposes
// by calling getAttr with a pre-specified mask.
// Used by read, write, lseek.
//
// +checklocks:i.attrMu
func (i *inode) reviseAttr(ctx context.Context, flags uint32, fh uint64) error {
// Never need atime for internal purposes.
_, err := i.getAttr(ctx, i.fs.VFSFilesystem(), vfs.StatOptions{
Mask: linux.STATX_BASIC_STATS &^ linux.STATX_ATIME,
}, flags, fh)
return err
}
// Stat implements kernfs.Inode.Stat.
func (i *inode) Stat(ctx context.Context, fs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) {
i.attrMu.Lock()
defer i.attrMu.Unlock()
attr, err := i.getAttr(ctx, fs, opts, 0, 0)
if err != nil {
return linux.Statx{}, err
}
return statFromFUSEAttr(attr, opts.Mask, i.fs.devMinor), nil
}
// DecRef implements kernfs.Inode.DecRef.
func (i *inode) DecRef(ctx context.Context) {
i.inodeRefs.DecRef(func() { i.Destroy(ctx) })
}
// StatFS implements kernfs.Inode.StatFS.
func (i *inode) StatFS(ctx context.Context, fs *vfs.Filesystem) (linux.Statfs, error) {
req := i.fs.conn.NewRequest(auth.CredentialsFromContext(ctx), pidFromContext(ctx), i.nodeID,
linux.FUSE_STATFS, &linux.FUSEEmptyIn{},
)
res, err := i.fs.conn.Call(ctx, req)
if err != nil {
return linux.Statfs{}, err
}
if err := res.Error(); err != nil {
return linux.Statfs{}, err
}
var out linux.FUSEStatfsOut
if err := res.UnmarshalPayload(&out); err != nil {
return linux.Statfs{}, err
}
return linux.Statfs{
Type: linux.FUSE_SUPER_MAGIC,
Blocks: uint64(out.Blocks),
BlocksFree: out.BlocksFree,
BlocksAvailable: out.BlocksAvailable,
Files: out.Files,
FilesFree: out.FilesFree,
BlockSize: int64(out.BlockSize),
NameLength: uint64(out.NameLength),
FragmentSize: int64(out.FragmentSize),
}, nil
}
// fattrMaskFromStats converts vfs.SetStatOptions.Stat.Mask to linux stats mask
// aligned with the attribute mask defined in include/linux/fs.h.
func fattrMaskFromStats(mask uint32) uint32 {
var fuseAttrMask uint32
maskMap := map[uint32]uint32{
linux.STATX_MODE: linux.FATTR_MODE,
linux.STATX_UID: linux.FATTR_UID,
linux.STATX_GID: linux.FATTR_GID,
linux.STATX_SIZE: linux.FATTR_SIZE,
linux.STATX_ATIME: linux.FATTR_ATIME,
linux.STATX_MTIME: linux.FATTR_MTIME,
linux.STATX_CTIME: linux.FATTR_CTIME,
}
for statxMask, fattrMask := range maskMap {
if mask&statxMask != 0 {
fuseAttrMask |= fattrMask
}
}
return fuseAttrMask
}
// SetStat implements kernfs.Inode.SetStat.
func (i *inode) SetStat(ctx context.Context, fs *vfs.Filesystem, creds *auth.Credentials, opts vfs.SetStatOptions) error {
i.attrMu.Lock()
defer i.attrMu.Unlock()
if err := vfs.CheckSetStat(ctx, creds, &opts, i.filemode(), auth.KUID(i.uid.Load()), auth.KGID(i.gid.Load())); err != nil {
return err
}
if opts.Stat.Mask == 0 {
return nil
}
return i.setAttr(ctx, fs, creds, opts, fhOptions{useFh: false})
}
type fhOptions struct {
useFh bool
fh uint64
}
// +checklocks:i.attrMu
func (i *inode) setAttr(ctx context.Context, fs *vfs.Filesystem, creds *auth.Credentials, opts vfs.SetStatOptions, fhOpts fhOptions) error {
// We should retain the original file type when assigning a new mode.
fattrMask := fattrMaskFromStats(opts.Stat.Mask)
if fhOpts.useFh {
fattrMask |= linux.FATTR_FH
}
if opts.Stat.Mask&linux.STATX_ATIME != 0 && opts.Stat.Atime.Nsec == linux.UTIME_NOW {
fattrMask |= linux.FATTR_ATIME_NOW
}
if opts.Stat.Mask&linux.STATX_MTIME != 0 && opts.Stat.Mtime.Nsec == linux.UTIME_NOW {
fattrMask |= linux.FATTR_ATIME_NOW
}
in := linux.FUSESetAttrIn{
Valid: fattrMask,
Fh: fhOpts.fh,
Size: opts.Stat.Size,
Atime: uint64(opts.Stat.Atime.Sec),
Mtime: uint64(opts.Stat.Mtime.Sec),
Ctime: uint64(opts.Stat.Ctime.Sec),
AtimeNsec: opts.Stat.Atime.Nsec,
MtimeNsec: opts.Stat.Mtime.Nsec,
CtimeNsec: opts.Stat.Ctime.Nsec,
Mode: uint32(uint16(i.filemode().FileType()) | opts.Stat.Mode),
UID: opts.Stat.UID,
GID: opts.Stat.GID,
}
req := i.fs.conn.NewRequest(creds, pidFromContext(ctx), i.nodeID, linux.FUSE_SETATTR, &in)
res, err := i.fs.conn.Call(ctx, req)
if err != nil {
return err
}
if err := res.Error(); err != nil {
return err
}
out := linux.FUSEAttrOut{}
if err := res.UnmarshalPayload(&out); err != nil {
return err
}
i.updateAttrs(out.Attr, int64(out.AttrValid), int64(out.AttrValidNsec))
return nil
}
// +checklocks:i.attrMu
func (i *inode) updateAttrs(attr linux.FUSEAttr, validSec, validNSec int64) {
i.fs.conn.mu.Lock()
i.attrVersion.Store(i.fs.conn.attributeVersion.Add(1))
i.fs.conn.mu.Unlock()
i.attrTime = i.fs.clock.Now().AddTime(time.FromTimespec(linux.Timespec{Sec: validSec, Nsec: validNSec}))
i.ino.Store(attr.Ino)
i.mode.Store((attr.Mode & 07777) | (i.mode.Load() & linux.S_IFMT))
i.uid.Store(attr.UID)
i.gid.Store(attr.GID)
i.atime.Store(attr.ATimeNsec())
i.mtime.Store(attr.MTimeNsec())
i.ctime.Store(attr.CTimeNsec())
i.size.Store(attr.Size)
i.nlink.Store(attr.Nlink)
if !i.fs.opts.defaultPermissions {
i.mode.Store(i.mode.Load() & ^uint32(linux.S_ISVTX))
}
}