fusefronted: move Create() and Open() to new file

And deduplicate the code a little.
This commit is contained in:
Jakob Unterwurzacher 2021-03-21 09:31:05 +01:00
parent 47a4d33f24
commit 3b9a1b628b
3 changed files with 125 additions and 118 deletions

View File

@ -53,18 +53,31 @@ type File struct {
rootNode *RootNode
}
// NewFile returns a new go-fuse File instance.
func NewFile(fd *os.File, rn *RootNode, st *syscall.Stat_t) *File {
// NewFile returns a new go-fuse File instance based on an already-open file
// descriptor. NewFile internally calls Fstat() on the fd. The resulting Stat_t
// is returned because node.Create() needs it.
//
// `cName` is only used for error logging and may be left blank.
func NewFile(fd int, cName string, rn *RootNode) (f *File, st *syscall.Stat_t, errno syscall.Errno) {
// Need device number and inode number for openfiletable locking
st = &syscall.Stat_t{}
if err := syscall.Fstat(fd, st); err != nil {
errno = fs.ToErrno(err)
return
}
qi := inomap.QInoFromStat(st)
e := openfiletable.Register(qi)
return &File{
fd: fd,
osFile := os.NewFile(uintptr(fd), cName)
f = &File{
fd: osFile,
contentEnc: rn.contentEnc,
qIno: qi,
fileTableEntry: e,
rootNode: rn,
}
return f, st, 0
}
// intFd - return the backing file descriptor as an integer.

View File

@ -2,7 +2,6 @@ package fusefrontend
import (
"context"
"os"
"syscall"
"golang.org/x/sys/unix"
@ -78,69 +77,6 @@ func (n *Node) Getattr(ctx context.Context, f fs.FileHandle, out *fuse.AttrOut)
return 0
}
// Create - FUSE call. Creates a new file.
//
// Symlink-safe through the use of Openat().
func (n *Node) Create(ctx context.Context, name string, flags uint32, mode uint32, out *fuse.EntryOut) (inode *fs.Inode, fh fs.FileHandle, fuseFlags uint32, errno syscall.Errno) {
dirfd, cName, errno := n.prepareAtSyscall(name)
if errno != 0 {
return
}
defer syscall.Close(dirfd)
var err error
fd := -1
// Make sure context is nil if we don't want to preserve the owner
rn := n.rootNode()
if !rn.args.PreserveOwner {
ctx = nil
}
newFlags := rn.mangleOpenFlags(flags)
// Handle long file name
ctx2 := toFuseCtx(ctx)
if !rn.args.PlaintextNames && nametransform.IsLongContent(cName) {
// Create ".name"
err = rn.nameTransform.WriteLongNameAt(dirfd, cName, name)
if err != nil {
return nil, nil, 0, fs.ToErrno(err)
}
// Create content
fd, err = syscallcompat.OpenatUser(dirfd, cName, newFlags|syscall.O_CREAT|syscall.O_EXCL, mode, ctx2)
if err != nil {
nametransform.DeleteLongNameAt(dirfd, cName)
}
} else {
// Create content, normal (short) file name
fd, err = syscallcompat.OpenatUser(dirfd, cName, newFlags|syscall.O_CREAT|syscall.O_EXCL, mode, ctx2)
}
if err != nil {
// xfstests generic/488 triggers this
if err == syscall.EMFILE {
var lim syscall.Rlimit
syscall.Getrlimit(syscall.RLIMIT_NOFILE, &lim)
tlog.Warn.Printf("Create %q: too many open files. Current \"ulimit -n\": %d", cName, lim.Cur)
}
return nil, nil, 0, fs.ToErrno(err)
}
// Get device number and inode number into `st`
var st syscall.Stat_t
err = syscall.Fstat(fd, &st)
if err != nil {
errno = fs.ToErrno(err)
return
}
// Save original stat values before newChild() translates the inode number.
// For an open fd, we assume the inode number cannot change behind our back,
// even in `-sharedstorage` mode.
origSt := st
ch := n.newChild(ctx, &st, out)
f := os.NewFile(uintptr(fd), cName)
return ch, NewFile(f, rn, &origSt), 0, 0
}
// Unlink - FUSE call. Delete a file.
//
// Symlink-safe through use of Unlinkat().
@ -179,56 +115,6 @@ func (n *Node) Readlink(ctx context.Context) (out []byte, errno syscall.Errno) {
return n.readlink(dirfd, cName)
}
// Open - FUSE call. Open already-existing file.
//
// Symlink-safe through Openat().
func (n *Node) Open(ctx context.Context, flags uint32) (fh fs.FileHandle, fuseFlags uint32, errno syscall.Errno) {
dirfd, cName, errno := n.prepareAtSyscall("")
if errno != 0 {
return
}
defer syscall.Close(dirfd)
rn := n.rootNode()
newFlags := rn.mangleOpenFlags(flags)
// Taking this lock makes sure we don't race openWriteOnlyFile()
rn.openWriteOnlyLock.RLock()
defer rn.openWriteOnlyLock.RUnlock()
if rn.args.KernelCache {
fuseFlags = fuse.FOPEN_KEEP_CACHE
}
// Open backing file
fd, err := syscallcompat.Openat(dirfd, cName, newFlags, 0)
// Handle a few specific errors
if err != nil {
if err == syscall.EMFILE {
var lim syscall.Rlimit
syscall.Getrlimit(syscall.RLIMIT_NOFILE, &lim)
tlog.Warn.Printf("Open %q: too many open files. Current \"ulimit -n\": %d", cName, lim.Cur)
}
if err == syscall.EACCES && (int(flags)&syscall.O_ACCMODE) == syscall.O_WRONLY {
fd, err = rn.openWriteOnlyFile(dirfd, cName, newFlags)
}
}
// Could not handle the error? Bail out
if err != nil {
errno = fs.ToErrno(err)
return
}
var st syscall.Stat_t
err = syscall.Fstat(fd, &st)
if err != nil {
errno = fs.ToErrno(err)
return
}
f := os.NewFile(uintptr(fd), cName)
fh = NewFile(f, rn, &st)
return
}
// Setattr - FUSE call. Called for chmod, truncate, utimens, ...
func (n *Node) Setattr(ctx context.Context, f fs.FileHandle, in *fuse.SetAttrIn, out *fuse.AttrOut) (errno syscall.Errno) {
// Use the fd if the kernel gave us one

View File

@ -0,0 +1,108 @@
package fusefrontend
import (
"context"
"syscall"
"github.com/hanwen/go-fuse/v2/fs"
"github.com/hanwen/go-fuse/v2/fuse"
"github.com/rfjakob/gocryptfs/internal/nametransform"
"github.com/rfjakob/gocryptfs/internal/syscallcompat"
"github.com/rfjakob/gocryptfs/internal/tlog"
)
// Open - FUSE call. Open already-existing file.
//
// Symlink-safe through Openat().
func (n *Node) Open(ctx context.Context, flags uint32) (fh fs.FileHandle, fuseFlags uint32, errno syscall.Errno) {
dirfd, cName, errno := n.prepareAtSyscall("")
if errno != 0 {
return
}
defer syscall.Close(dirfd)
rn := n.rootNode()
newFlags := rn.mangleOpenFlags(flags)
// Taking this lock makes sure we don't race openWriteOnlyFile()
rn.openWriteOnlyLock.RLock()
defer rn.openWriteOnlyLock.RUnlock()
if rn.args.KernelCache {
fuseFlags = fuse.FOPEN_KEEP_CACHE
}
// Open backing file
fd, err := syscallcompat.Openat(dirfd, cName, newFlags, 0)
// Handle a few specific errors
if err != nil {
if err == syscall.EMFILE {
var lim syscall.Rlimit
syscall.Getrlimit(syscall.RLIMIT_NOFILE, &lim)
tlog.Warn.Printf("Open %q: too many open files. Current \"ulimit -n\": %d", cName, lim.Cur)
}
if err == syscall.EACCES && (int(flags)&syscall.O_ACCMODE) == syscall.O_WRONLY {
fd, err = rn.openWriteOnlyFile(dirfd, cName, newFlags)
}
}
// Could not handle the error? Bail out
if err != nil {
errno = fs.ToErrno(err)
return
}
fh, _, errno = NewFile(fd, cName, rn)
return fh, fuseFlags, errno
}
// Create - FUSE call. Creates a new file.
//
// Symlink-safe through the use of Openat().
func (n *Node) Create(ctx context.Context, name string, flags uint32, mode uint32, out *fuse.EntryOut) (inode *fs.Inode, fh fs.FileHandle, fuseFlags uint32, errno syscall.Errno) {
dirfd, cName, errno := n.prepareAtSyscall(name)
if errno != 0 {
return
}
defer syscall.Close(dirfd)
var err error
fd := -1
// Make sure context is nil if we don't want to preserve the owner
rn := n.rootNode()
if !rn.args.PreserveOwner {
ctx = nil
}
newFlags := rn.mangleOpenFlags(flags)
// Handle long file name
ctx2 := toFuseCtx(ctx)
if !rn.args.PlaintextNames && nametransform.IsLongContent(cName) {
// Create ".name"
err = rn.nameTransform.WriteLongNameAt(dirfd, cName, name)
if err != nil {
return nil, nil, 0, fs.ToErrno(err)
}
// Create content
fd, err = syscallcompat.OpenatUser(dirfd, cName, newFlags|syscall.O_CREAT|syscall.O_EXCL, mode, ctx2)
if err != nil {
nametransform.DeleteLongNameAt(dirfd, cName)
}
} else {
// Create content, normal (short) file name
fd, err = syscallcompat.OpenatUser(dirfd, cName, newFlags|syscall.O_CREAT|syscall.O_EXCL, mode, ctx2)
}
if err != nil {
// xfstests generic/488 triggers this
if err == syscall.EMFILE {
var lim syscall.Rlimit
syscall.Getrlimit(syscall.RLIMIT_NOFILE, &lim)
tlog.Warn.Printf("Create %q: too many open files. Current \"ulimit -n\": %d", cName, lim.Cur)
}
return nil, nil, 0, fs.ToErrno(err)
}
fh, st, errno := NewFile(fd, cName, rn)
if errno != 0 {
return
}
inode = n.newChild(ctx, st, out)
return inode, fh, fuseFlags, errno
}