ext: Move to pkg/sentry/fsimpl.

fsimpl is the keeper of all filesystem implementations in VFS2.

PiperOrigin-RevId: 262617869

1 files changed, 0 insertions, 135 deletions

diff --git a/pkg/sentry/fs/ext/ext.go b/pkg/sentry/fs/ext/ext.go
deleted file mode 100644
index 632ba97f8..000000000
--- a/pkg/sentry/fs/ext/ext.go
+++ /dev/null
@@ -1,135 +0,0 @@
-// Copyright 2019 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 ext implements readonly ext(2/3/4) filesystems.
-package ext
-
-import (
-	"errors"
-	"fmt"
-	"io"
-
-	"gvisor.dev/gvisor/pkg/abi/linux"
-	"gvisor.dev/gvisor/pkg/fd"
-	"gvisor.dev/gvisor/pkg/log"
-	"gvisor.dev/gvisor/pkg/sentry/context"
-	"gvisor.dev/gvisor/pkg/sentry/fs/ext/disklayout"
-	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
-	"gvisor.dev/gvisor/pkg/sentry/vfs"
-	"gvisor.dev/gvisor/pkg/syserror"
-)
-
-// FilesystemType implements vfs.FilesystemType.
-type FilesystemType struct{}
-
-// Compiles only if FilesystemType implements vfs.FilesystemType.
-var _ vfs.FilesystemType = (*FilesystemType)(nil)
-
-// getDeviceFd returns an io.ReaderAt to the underlying device.
-// Currently there are two ways of mounting an ext(2/3/4) fs:
-//   1. Specify a mount with our internal special MountType in the OCI spec.
-//   2. Expose the device to the container and mount it from application layer.
-func getDeviceFd(source string, opts vfs.NewFilesystemOptions) (io.ReaderAt, error) {
-	if opts.InternalData == nil {
-		// User mount call.
-		// TODO(b/134676337): Open the device specified by `source` and return that.
-		panic("unimplemented")
-	}
-
-	// NewFilesystem call originated from within the sentry.
-	devFd, ok := opts.InternalData.(int)
-	if !ok {
-		return nil, errors.New("internal data for ext fs must be an int containing the file descriptor to device")
-	}
-
-	if devFd < 0 {
-		return nil, fmt.Errorf("ext device file descriptor is not valid: %d", devFd)
-	}
-
-	// The fd.ReadWriter returned from fd.NewReadWriter() does not take ownership
-	// of the file descriptor and hence will not close it when it is garbage
-	// collected.
-	return fd.NewReadWriter(devFd), nil
-}
-
-// isCompatible checks if the superblock has feature sets which are compatible.
-// We only need to check the superblock incompatible feature set since we are
-// mounting readonly. We will also need to check readonly compatible feature
-// set when mounting for read/write.
-func isCompatible(sb disklayout.SuperBlock) bool {
-	// Please note that what is being checked is limited based on the fact that we
-	// are mounting readonly and that we are not journaling. When mounting
-	// read/write or with a journal, this must be reevaluated.
-	incompatFeatures := sb.IncompatibleFeatures()
-	if incompatFeatures.MetaBG {
-		log.Warningf("ext fs: meta block groups are not supported")
-		return false
-	}
-	if incompatFeatures.MMP {
-		log.Warningf("ext fs: multiple mount protection is not supported")
-		return false
-	}
-	if incompatFeatures.Encrypted {
-		log.Warningf("ext fs: encrypted inodes not supported")
-		return false
-	}
-	if incompatFeatures.InlineData {
-		log.Warningf("ext fs: inline files not supported")
-		return false
-	}
-	return true
-}
-
-// NewFilesystem implements vfs.FilesystemType.NewFilesystem.
-func (FilesystemType) NewFilesystem(ctx context.Context, creds *auth.Credentials, source string, opts vfs.NewFilesystemOptions) (*vfs.Filesystem, *vfs.Dentry, error) {
-	// TODO(b/134676337): Ensure that the user is mounting readonly. If not,
-	// EACCESS should be returned according to mount(2). Filesystem independent
-	// flags (like readonly) are currently not available in pkg/sentry/vfs.
-
-	dev, err := getDeviceFd(source, opts)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	fs := filesystem{dev: dev, inodeCache: make(map[uint32]*inode)}
-	fs.vfsfs.Init(&fs)
-	fs.sb, err = readSuperBlock(dev)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	if fs.sb.Magic() != linux.EXT_SUPER_MAGIC {
-		// mount(2) specifies that EINVAL should be returned if the superblock is
-		// invalid.
-		return nil, nil, syserror.EINVAL
-	}
-
-	// Refuse to mount if the filesystem is incompatible.
-	if !isCompatible(fs.sb) {
-		return nil, nil, syserror.EINVAL
-	}
-
-	fs.bgs, err = readBlockGroups(dev, fs.sb)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	rootInode, err := fs.getOrCreateInodeLocked(disklayout.RootDirInode)
-	if err != nil {
-		return nil, nil, err
-	}
-	rootInode.incRef()
-
-	return &fs.vfsfs, &newDentry(rootInode).vfsd, nil
-}