Clean up vfs2 fallocate.

Move to setstat.go and add a FileDescription wrapper method.

PiperOrigin-RevId: 324165277

pkg/sentry/syscalls/linux/vfs2/filesystem.go

@@ -18,7 +18,6 @@ import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
-	"gvisor.dev/gvisor/pkg/sentry/limits"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/usermem"
@@ -245,55 +244,6 @@ func renameat(t *kernel.Task, olddirfd int32, oldpathAddr usermem.Addr, newdirfd
 	})
 }
 
-// Fallocate implements linux system call fallocate(2).
-func Fallocate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
-	fd := args[0].Int()
-	mode := args[1].Uint64()
-	offset := args[2].Int64()
-	length := args[3].Int64()
-
-	file := t.GetFileVFS2(fd)
-
-	if file == nil {
-		return 0, nil, syserror.EBADF
-	}
-	defer file.DecRef()
-
-	if !file.IsWritable() {
-		return 0, nil, syserror.EBADF
-	}
-
-	if mode != 0 {
-		return 0, nil, syserror.ENOTSUP
-	}
-
-	if offset < 0 || length <= 0 {
-		return 0, nil, syserror.EINVAL
-	}
-
-	size := offset + length
-
-	if size < 0 {
-		return 0, nil, syserror.EFBIG
-	}
-
-	limit := limits.FromContext(t).Get(limits.FileSize).Cur
-
-	if uint64(size) >= limit {
-		t.SendSignal(&arch.SignalInfo{
-			Signo: int32(linux.SIGXFSZ),
-			Code:  arch.SignalInfoUser,
-		})
-		return 0, nil, syserror.EFBIG
-	}
-
-	return 0, nil, file.Impl().Allocate(t, mode, uint64(offset), uint64(length))
-
-	// File length modified, generate notification.
-	// TODO(gvisor.dev/issue/1479): Reenable when Inotify is ported.
-	// file.Dirent.InotifyEvent(linux.IN_MODIFY, 0)
-}
-
 // Rmdir implements Linux syscall rmdir(2).
 func Rmdir(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
 	pathAddr := args[0].Pointer()

pkg/sentry/syscalls/linux/vfs2/setstat.go

@@ -20,6 +20,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sentry/limits"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/usermem"
@@ -211,6 +212,55 @@ func Ftruncate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys
 	return 0, nil, handleSetSizeError(t, err)
 }
 
+// Fallocate implements linux system call fallocate(2).
+func Fallocate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	fd := args[0].Int()
+	mode := args[1].Uint64()
+	offset := args[2].Int64()
+	length := args[3].Int64()
+
+	file := t.GetFileVFS2(fd)
+
+	if file == nil {
+		return 0, nil, syserror.EBADF
+	}
+	defer file.DecRef()
+
+	if !file.IsWritable() {
+		return 0, nil, syserror.EBADF
+	}
+
+	if mode != 0 {
+		return 0, nil, syserror.ENOTSUP
+	}
+
+	if offset < 0 || length <= 0 {
+		return 0, nil, syserror.EINVAL
+	}
+
+	size := offset + length
+
+	if size < 0 {
+		return 0, nil, syserror.EFBIG
+	}
+
+	limit := limits.FromContext(t).Get(limits.FileSize).Cur
+
+	if uint64(size) >= limit {
+		t.SendSignal(&arch.SignalInfo{
+			Signo: int32(linux.SIGXFSZ),
+			Code:  arch.SignalInfoUser,
+		})
+		return 0, nil, syserror.EFBIG
+	}
+
+	return 0, nil, file.Allocate(t, mode, uint64(offset), uint64(length))
+
+	// File length modified, generate notification.
+	// TODO(gvisor.dev/issue/1479): Reenable when Inotify is ported.
+	// file.Dirent.InotifyEvent(linux.IN_MODIFY, 0)
+}
+
 // Utime implements Linux syscall utime(2).
 func Utime(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
 	pathAddr := args[0].Pointer()

pkg/sentry/vfs/file_description.go

@@ -354,7 +354,7 @@ type FileDescriptionImpl interface {
 	// represented by the FileDescription.
 	StatFS(ctx context.Context) (linux.Statfs, error)
 
-	// Allocate grows file represented by FileDescription to offset + length bytes.
+	// Allocate grows the file to offset + length bytes.
 	// Only mode == 0 is supported currently.
 	Allocate(ctx context.Context, mode, offset, length uint64) error
 
@@ -563,6 +563,11 @@ func (fd *FileDescription) StatFS(ctx context.Context) (linux.Statfs, error) {
 	return fd.impl.StatFS(ctx)
 }
 
+// Allocate grows file represented by FileDescription to offset + length bytes.
+func (fd *FileDescription) Allocate(ctx context.Context, mode, offset, length uint64) error {
+	return fd.impl.Allocate(ctx, mode, offset, length)
+}
+
 // Readiness implements waiter.Waitable.Readiness.
 //
 // It returns fd's I/O readiness.