1 files changed, 0 insertions, 443 deletions
diff --git a/pkg/sentry/fs/ext/filesystem.go b/pkg/sentry/fs/ext/filesystem.go
deleted file mode 100644
index e08839f48..000000000
--- a/pkg/sentry/fs/ext/filesystem.go
+++ /dev/null
@@ -1,443 +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
-
-import (
-	"errors"
-	"io"
-	"sync"
-
-	"gvisor.dev/gvisor/pkg/abi/linux"
-	"gvisor.dev/gvisor/pkg/sentry/context"
-	"gvisor.dev/gvisor/pkg/sentry/fs/ext/disklayout"
-	"gvisor.dev/gvisor/pkg/sentry/vfs"
-	"gvisor.dev/gvisor/pkg/syserror"
-)
-
-var (
-	// errResolveDirent indicates that the vfs.ResolvingPath.Component() does
-	// not exist on the dentry tree but does exist on disk. So it has to be read in
-	// using the in-memory dirent and added to the dentry tree. Usually indicates
-	// the need to lock filesystem.mu for writing.
-	errResolveDirent = errors.New("resolve path component using dirent")
-)
-
-// filesystem implements vfs.FilesystemImpl.
-type filesystem struct {
-	vfsfs vfs.Filesystem
-
-	// mu serializes changes to the Dentry tree.
-	mu sync.RWMutex
-
-	// dev represents the underlying fs device. It does not require protection
-	// because io.ReaderAt permits concurrent read calls to it. It translates to
-	// the pread syscall which passes on the read request directly to the device
-	// driver. Device drivers are intelligent in serving multiple concurrent read
-	// requests in the optimal order (taking locality into consideration).
-	dev io.ReaderAt
-
-	// inodeCache maps absolute inode numbers to the corresponding Inode struct.
-	// Inodes should be removed from this once their reference count hits 0.
-	//
-	// Protected by mu because most additions (see IterDirents) and all removals
-	// from this corresponds to a change in the dentry tree.
-	inodeCache map[uint32]*inode
-
-	// sb represents the filesystem superblock. Immutable after initialization.
-	sb disklayout.SuperBlock
-
-	// bgs represents all the block group descriptors for the filesystem.
-	// Immutable after initialization.
-	bgs []disklayout.BlockGroup
-}
-
-// Compiles only if filesystem implements vfs.FilesystemImpl.
-var _ vfs.FilesystemImpl = (*filesystem)(nil)
-
-// stepLocked resolves rp.Component() in parent directory vfsd. The write
-// parameter passed tells if the caller has acquired filesystem.mu for writing
-// or not. If set to true, an existing inode on disk can be added to the dentry
-// tree if not present already.
-//
-// stepLocked is loosely analogous to fs/namei.c:walk_component().
-//
-// Preconditions:
-//     - filesystem.mu must be locked (for writing if write param is true).
-//     - !rp.Done().
-//     - inode == vfsd.Impl().(*Dentry).inode.
-func stepLocked(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, inode *inode, write bool) (*vfs.Dentry, *inode, error) {
-	if !inode.isDir() {
-		return nil, nil, syserror.ENOTDIR
-	}
-	if err := inode.checkPermissions(rp.Credentials(), vfs.MayExec); err != nil {
-		return nil, nil, err
-	}
-
-	for {
-		nextVFSD, err := rp.ResolveComponent(vfsd)
-		if err != nil {
-			return nil, nil, err
-		}
-		if nextVFSD == nil {
-			// Since the Dentry tree is not the sole source of truth for extfs, if it's
-			// not in the Dentry tree, it might need to be pulled from disk.
-			childDirent, ok := inode.impl.(*directory).childMap[rp.Component()]
-			if !ok {
-				// The underlying inode does not exist on disk.
-				return nil, nil, syserror.ENOENT
-			}
-
-			if !write {
-				// filesystem.mu must be held for writing to add to the dentry tree.
-				return nil, nil, errResolveDirent
-			}
-
-			// Create and add the component's dirent to the dentry tree.
-			fs := rp.Mount().Filesystem().Impl().(*filesystem)
-			childInode, err := fs.getOrCreateInodeLocked(childDirent.diskDirent.Inode())
-			if err != nil {
-				return nil, nil, err
-			}
-			// incRef because this is being added to the dentry tree.
-			childInode.incRef()
-			child := newDentry(childInode)
-			vfsd.InsertChild(&child.vfsd, rp.Component())
-
-			// Continue as usual now that nextVFSD is not nil.
-			nextVFSD = &child.vfsd
-		}
-		nextInode := nextVFSD.Impl().(*dentry).inode
-		if nextInode.isSymlink() && rp.ShouldFollowSymlink() {
-			if err := rp.HandleSymlink(inode.impl.(*symlink).target); err != nil {
-				return nil, nil, err
-			}
-			continue
-		}
-		rp.Advance()
-		return nextVFSD, nextInode, nil
-	}
-}
-
-// walkLocked resolves rp to an existing file. The write parameter
-// passed tells if the caller has acquired filesystem.mu for writing or not.
-// If set to true, additions can be made to the dentry tree while walking.
-// If errResolveDirent is returned, the walk needs to be continued with an
-// upgraded filesystem.mu.
-//
-// walkLocked is loosely analogous to Linux's fs/namei.c:path_lookupat().
-//
-// Preconditions:
-//     - filesystem.mu must be locked (for writing if write param is true).
-func walkLocked(rp *vfs.ResolvingPath, write bool) (*vfs.Dentry, *inode, error) {
-	vfsd := rp.Start()
-	inode := vfsd.Impl().(*dentry).inode
-	for !rp.Done() {
-		var err error
-		vfsd, inode, err = stepLocked(rp, vfsd, inode, write)
-		if err != nil {
-			return nil, nil, err
-		}
-	}
-	if rp.MustBeDir() && !inode.isDir() {
-		return nil, nil, syserror.ENOTDIR
-	}
-	return vfsd, inode, nil
-}
-
-// walkParentLocked resolves all but the last path component of rp to an
-// existing directory. It does not check that the returned directory is
-// searchable by the provider of rp. The write parameter passed tells if the
-// caller has acquired filesystem.mu for writing or not. If set to true,
-// additions can be made to the dentry tree while walking.
-// If errResolveDirent is returned, the walk needs to be continued with an
-// upgraded filesystem.mu.
-//
-// walkParentLocked is loosely analogous to Linux's fs/namei.c:path_parentat().
-//
-// Preconditions:
-//     - filesystem.mu must be locked (for writing if write param is true).
-//     - !rp.Done().
-func walkParentLocked(rp *vfs.ResolvingPath, write bool) (*vfs.Dentry, *inode, error) {
-	vfsd := rp.Start()
-	inode := vfsd.Impl().(*dentry).inode
-	for !rp.Final() {
-		var err error
-		vfsd, inode, err = stepLocked(rp, vfsd, inode, write)
-		if err != nil {
-			return nil, nil, err
-		}
-	}
-	if !inode.isDir() {
-		return nil, nil, syserror.ENOTDIR
-	}
-	return vfsd, inode, nil
-}
-
-// walk resolves rp to an existing file. If parent is set to true, it resolves
-// the rp till the parent of the last component which should be an existing
-// directory. If parent is false then resolves rp entirely. Attemps to resolve
-// the path as far as it can with a read lock and upgrades the lock if needed.
-func (fs *filesystem) walk(rp *vfs.ResolvingPath, parent bool) (*vfs.Dentry, *inode, error) {
-	var (
-		vfsd  *vfs.Dentry
-		inode *inode
-		err   error
-	)
-
-	// Try walking with the hopes that all dentries have already been pulled out
-	// of disk. This reduces congestion (allows concurrent walks).
-	fs.mu.RLock()
-	if parent {
-		vfsd, inode, err = walkParentLocked(rp, false)
-	} else {
-		vfsd, inode, err = walkLocked(rp, false)
-	}
-	fs.mu.RUnlock()
-
-	if err == errResolveDirent {
-		// Upgrade lock and continue walking. Lock upgrading in the middle of the
-		// walk is fine as this is a read only filesystem.
-		fs.mu.Lock()
-		if parent {
-			vfsd, inode, err = walkParentLocked(rp, true)
-		} else {
-			vfsd, inode, err = walkLocked(rp, true)
-		}
-		fs.mu.Unlock()
-	}
-
-	return vfsd, inode, err
-}
-
-// getOrCreateInodeLocked gets the inode corresponding to the inode number passed in.
-// It creates a new one with the given inode number if one does not exist.
-// The caller must increment the ref count if adding this to the dentry tree.
-//
-// Precondition: must be holding fs.mu for writing.
-func (fs *filesystem) getOrCreateInodeLocked(inodeNum uint32) (*inode, error) {
-	if in, ok := fs.inodeCache[inodeNum]; ok {
-		return in, nil
-	}
-
-	in, err := newInode(fs, inodeNum)
-	if err != nil {
-		return nil, err
-	}
-
-	fs.inodeCache[inodeNum] = in
-	return in, nil
-}
-
-// statTo writes the statfs fields to the output parameter.
-func (fs *filesystem) statTo(stat *linux.Statfs) {
-	stat.Type = uint64(fs.sb.Magic())
-	stat.BlockSize = int64(fs.sb.BlockSize())
-	stat.Blocks = fs.sb.BlocksCount()
-	stat.BlocksFree = fs.sb.FreeBlocksCount()
-	stat.BlocksAvailable = fs.sb.FreeBlocksCount()
-	stat.Files = uint64(fs.sb.InodesCount())
-	stat.FilesFree = uint64(fs.sb.FreeInodesCount())
-	stat.NameLength = disklayout.MaxFileName
-	stat.FragmentSize = int64(fs.sb.BlockSize())
-	// TODO(b/134676337): Set Statfs.Flags and Statfs.FSID.
-}
-
-// GetDentryAt implements vfs.FilesystemImpl.GetDentryAt.
-func (fs *filesystem) GetDentryAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.GetDentryOptions) (*vfs.Dentry, error) {
-	vfsd, inode, err := fs.walk(rp, false)
-	if err != nil {
-		return nil, err
-	}
-
-	if opts.CheckSearchable {
-		if !inode.isDir() {
-			return nil, syserror.ENOTDIR
-		}
-		if err := inode.checkPermissions(rp.Credentials(), vfs.MayExec); err != nil {
-			return nil, err
-		}
-	}
-
-	inode.incRef()
-	return vfsd, nil
-}
-
-// OpenAt implements vfs.FilesystemImpl.OpenAt.
-func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
-	vfsd, inode, err := fs.walk(rp, false)
-	if err != nil {
-		return nil, err
-	}
-
-	// EROFS is returned if write access is needed.
-	if vfs.MayWriteFileWithOpenFlags(opts.Flags) || opts.Flags&(linux.O_CREAT|linux.O_EXCL|linux.O_TMPFILE) != 0 {
-		return nil, syserror.EROFS
-	}
-	return inode.open(rp, vfsd, opts.Flags)
-}
-
-// ReadlinkAt implements vfs.FilesystemImpl.ReadlinkAt.
-func (fs *filesystem) ReadlinkAt(ctx context.Context, rp *vfs.ResolvingPath) (string, error) {
-	_, inode, err := fs.walk(rp, false)
-	if err != nil {
-		return "", err
-	}
-	symlink, ok := inode.impl.(*symlink)
-	if !ok {
-		return "", syserror.EINVAL
-	}
-	return symlink.target, nil
-}
-
-// StatAt implements vfs.FilesystemImpl.StatAt.
-func (fs *filesystem) StatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.StatOptions) (linux.Statx, error) {
-	_, inode, err := fs.walk(rp, false)
-	if err != nil {
-		return linux.Statx{}, err
-	}
-	var stat linux.Statx
-	inode.statTo(&stat)
-	return stat, nil
-}
-
-// StatFSAt implements vfs.FilesystemImpl.StatFSAt.
-func (fs *filesystem) StatFSAt(ctx context.Context, rp *vfs.ResolvingPath) (linux.Statfs, error) {
-	if _, _, err := fs.walk(rp, false); err != nil {
-		return linux.Statfs{}, err
-	}
-
-	var stat linux.Statfs
-	fs.statTo(&stat)
-	return stat, nil
-}
-
-// Release implements vfs.FilesystemImpl.Release.
-func (fs *filesystem) Release() {}
-
-// Sync implements vfs.FilesystemImpl.Sync.
-func (fs *filesystem) Sync(ctx context.Context) error {
-	// This is a readonly filesystem for now.
-	return nil
-}
-
-// The vfs.FilesystemImpl functions below return EROFS because their respective
-// man pages say that EROFS must be returned if the path resolves to a file on
-// this read-only filesystem.
-
-// LinkAt implements vfs.FilesystemImpl.LinkAt.
-func (fs *filesystem) LinkAt(ctx context.Context, rp *vfs.ResolvingPath, vd vfs.VirtualDentry) error {
-	if rp.Done() {
-		return syserror.EEXIST
-	}
-
-	if _, _, err := fs.walk(rp, true); err != nil {
-		return err
-	}
-
-	return syserror.EROFS
-}
-
-// MkdirAt implements vfs.FilesystemImpl.MkdirAt.
-func (fs *filesystem) MkdirAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.MkdirOptions) error {
-	if rp.Done() {
-		return syserror.EEXIST
-	}
-
-	if _, _, err := fs.walk(rp, true); err != nil {
-		return err
-	}
-
-	return syserror.EROFS
-}
-
-// MknodAt implements vfs.FilesystemImpl.MknodAt.
-func (fs *filesystem) MknodAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.MknodOptions) error {
-	if rp.Done() {
-		return syserror.EEXIST
-	}
-
-	_, _, err := fs.walk(rp, true)
-	if err != nil {
-		return err
-	}
-
-	return syserror.EROFS
-}
-
-// RenameAt implements vfs.FilesystemImpl.RenameAt.
-func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, vd vfs.VirtualDentry, opts vfs.RenameOptions) error {
-	if rp.Done() {
-		return syserror.ENOENT
-	}
-
-	_, _, err := fs.walk(rp, false)
-	if err != nil {
-		return err
-	}
-
-	return syserror.EROFS
-}
-
-// RmdirAt implements vfs.FilesystemImpl.RmdirAt.
-func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error {
-	_, inode, err := fs.walk(rp, false)
-	if err != nil {
-		return err
-	}
-
-	if !inode.isDir() {
-		return syserror.ENOTDIR
-	}
-
-	return syserror.EROFS
-}
-
-// SetStatAt implements vfs.FilesystemImpl.SetStatAt.
-func (fs *filesystem) SetStatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.SetStatOptions) error {
-	_, _, err := fs.walk(rp, false)
-	if err != nil {
-		return err
-	}
-
-	return syserror.EROFS
-}
-
-// SymlinkAt implements vfs.FilesystemImpl.SymlinkAt.
-func (fs *filesystem) SymlinkAt(ctx context.Context, rp *vfs.ResolvingPath, target string) error {
-	if rp.Done() {
-		return syserror.EEXIST
-	}
-
-	_, _, err := fs.walk(rp, true)
-	if err != nil {
-		return err
-	}
-
-	return syserror.EROFS
-}
-
-// UnlinkAt implements vfs.FilesystemImpl.UnlinkAt.
-func (fs *filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error {
-	_, inode, err := fs.walk(rp, false)
-	if err != nil {
-		return err
-	}
-
-	if inode.isDir() {
-		return syserror.EISDIR
-	}
-
-	return syserror.EROFS
-}