1 files changed, 0 insertions, 237 deletions
diff --git a/pkg/sentry/fs/ext/extent_file.go b/pkg/sentry/fs/ext/extent_file.go
deleted file mode 100644
index 1b9bf449b..000000000
--- a/pkg/sentry/fs/ext/extent_file.go
+++ /dev/null
@@ -1,237 +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 (
-	"io"
-	"sort"
-
-	"gvisor.dev/gvisor/pkg/binary"
-	"gvisor.dev/gvisor/pkg/sentry/fs/ext/disklayout"
-	"gvisor.dev/gvisor/pkg/syserror"
-)
-
-// extentFile is a type of regular file which uses extents to store file data.
-type extentFile struct {
-	regFile regularFile
-
-	// root is the root extent node. This lives in the 60 byte diskInode.Data().
-	// Immutable.
-	root disklayout.ExtentNode
-}
-
-// Compiles only if extentFile implements io.ReaderAt.
-var _ io.ReaderAt = (*extentFile)(nil)
-
-// newExtentFile is the extent file constructor. It reads the entire extent
-// tree into memory.
-// TODO(b/134676337): Build extent tree on demand to reduce memory usage.
-func newExtentFile(regFile regularFile) (*extentFile, error) {
-	file := &extentFile{regFile: regFile}
-	file.regFile.impl = file
-	err := file.buildExtTree()
-	if err != nil {
-		return nil, err
-	}
-	return file, nil
-}
-
-// buildExtTree builds the extent tree by reading it from disk by doing
-// running a simple DFS. It first reads the root node from the inode struct in
-// memory. Then it recursively builds the rest of the tree by reading it off
-// disk.
-//
-// Precondition: inode flag InExtents must be set.
-func (f *extentFile) buildExtTree() error {
-	rootNodeData := f.regFile.inode.diskInode.Data()
-
-	binary.Unmarshal(rootNodeData[:disklayout.ExtentStructsSize], binary.LittleEndian, &f.root.Header)
-
-	// Root node can not have more than 4 entries: 60 bytes = 1 header + 4 entries.
-	if f.root.Header.NumEntries > 4 {
-		// read(2) specifies that EINVAL should be returned if the file is unsuitable
-		// for reading.
-		return syserror.EINVAL
-	}
-
-	f.root.Entries = make([]disklayout.ExtentEntryPair, f.root.Header.NumEntries)
-	for i, off := uint16(0), disklayout.ExtentStructsSize; i < f.root.Header.NumEntries; i, off = i+1, off+disklayout.ExtentStructsSize {
-		var curEntry disklayout.ExtentEntry
-		if f.root.Header.Height == 0 {
-			// Leaf node.
-			curEntry = &disklayout.Extent{}
-		} else {
-			// Internal node.
-			curEntry = &disklayout.ExtentIdx{}
-		}
-		binary.Unmarshal(rootNodeData[off:off+disklayout.ExtentStructsSize], binary.LittleEndian, curEntry)
-		f.root.Entries[i].Entry = curEntry
-	}
-
-	// If this node is internal, perform DFS.
-	if f.root.Header.Height > 0 {
-		for i := uint16(0); i < f.root.Header.NumEntries; i++ {
-			var err error
-			if f.root.Entries[i].Node, err = f.buildExtTreeFromDisk(f.root.Entries[i].Entry); err != nil {
-				return err
-			}
-		}
-	}
-
-	return nil
-}
-
-// buildExtTreeFromDisk reads the extent tree nodes from disk and recursively
-// builds the tree. Performs a simple DFS. It returns the ExtentNode pointed to
-// by the ExtentEntry.
-func (f *extentFile) buildExtTreeFromDisk(entry disklayout.ExtentEntry) (*disklayout.ExtentNode, error) {
-	var header disklayout.ExtentHeader
-	off := entry.PhysicalBlock() * f.regFile.inode.blkSize
-	err := readFromDisk(f.regFile.inode.dev, int64(off), &header)
-	if err != nil {
-		return nil, err
-	}
-
-	entries := make([]disklayout.ExtentEntryPair, header.NumEntries)
-	for i, off := uint16(0), off+disklayout.ExtentStructsSize; i < header.NumEntries; i, off = i+1, off+disklayout.ExtentStructsSize {
-		var curEntry disklayout.ExtentEntry
-		if header.Height == 0 {
-			// Leaf node.
-			curEntry = &disklayout.Extent{}
-		} else {
-			// Internal node.
-			curEntry = &disklayout.ExtentIdx{}
-		}
-
-		err := readFromDisk(f.regFile.inode.dev, int64(off), curEntry)
-		if err != nil {
-			return nil, err
-		}
-		entries[i].Entry = curEntry
-	}
-
-	// If this node is internal, perform DFS.
-	if header.Height > 0 {
-		for i := uint16(0); i < header.NumEntries; i++ {
-			var err error
-			entries[i].Node, err = f.buildExtTreeFromDisk(entries[i].Entry)
-			if err != nil {
-				return nil, err
-			}
-		}
-	}
-
-	return &disklayout.ExtentNode{header, entries}, nil
-}
-
-// ReadAt implements io.ReaderAt.ReadAt.
-func (f *extentFile) ReadAt(dst []byte, off int64) (int, error) {
-	if len(dst) == 0 {
-		return 0, nil
-	}
-
-	if off < 0 {
-		return 0, syserror.EINVAL
-	}
-
-	if uint64(off) >= f.regFile.inode.diskInode.Size() {
-		return 0, io.EOF
-	}
-
-	n, err := f.read(&f.root, uint64(off), dst)
-	if n < len(dst) && err == nil {
-		err = io.EOF
-	}
-	return n, err
-}
-
-// read is the recursive step of extentFile.ReadAt which traverses the extent
-// tree from the node passed and reads file data.
-func (f *extentFile) read(node *disklayout.ExtentNode, off uint64, dst []byte) (int, error) {
-	// Perform a binary search for the node covering bytes starting at r.fileOff.
-	// A highly fragmented filesystem can have upto 340 entries and so linear
-	// search should be avoided. Finds the first entry which does not cover the
-	// file block we want and subtracts 1 to get the desired index.
-	fileBlk := uint32(off / f.regFile.inode.blkSize)
-	n := len(node.Entries)
-	found := sort.Search(n, func(i int) bool {
-		return node.Entries[i].Entry.FileBlock() > fileBlk
-	}) - 1
-
-	// We should be in this recursive step only if the data we want exists under
-	// the current node.
-	if found < 0 {
-		panic("searching for a file block in an extent entry which does not cover it")
-	}
-
-	read := 0
-	toRead := len(dst)
-	var curR int
-	var err error
-	for i := found; i < n && read < toRead; i++ {
-		if node.Header.Height == 0 {
-			curR, err = f.readFromExtent(node.Entries[i].Entry.(*disklayout.Extent), off, dst[read:])
-		} else {
-			curR, err = f.read(node.Entries[i].Node, off, dst[read:])
-		}
-
-		read += curR
-		off += uint64(curR)
-		if err != nil {
-			return read, err
-		}
-	}
-
-	return read, nil
-}
-
-// readFromExtent reads file data from the extent. It takes advantage of the
-// sequential nature of extents and reads file data from multiple blocks in one
-// call.
-//
-// A non-nil error indicates that this is a partial read and there is probably
-// more to read from this extent. The caller should propagate the error upward
-// and not move to the next extent in the tree.
-//
-// A subsequent call to extentReader.Read should continue reading from where we
-// left off as expected.
-func (f *extentFile) readFromExtent(ex *disklayout.Extent, off uint64, dst []byte) (int, error) {
-	curFileBlk := uint32(off / f.regFile.inode.blkSize)
-	exFirstFileBlk := ex.FileBlock()
-	exLastFileBlk := exFirstFileBlk + uint32(ex.Length) // This is exclusive.
-
-	// We should be in this recursive step only if the data we want exists under
-	// the current extent.
-	if curFileBlk < exFirstFileBlk || exLastFileBlk <= curFileBlk {
-		panic("searching for a file block in an extent which does not cover it")
-	}
-
-	curPhyBlk := uint64(curFileBlk-exFirstFileBlk) + ex.PhysicalBlock()
-	readStart := curPhyBlk*f.regFile.inode.blkSize + (off % f.regFile.inode.blkSize)
-
-	endPhyBlk := ex.PhysicalBlock() + uint64(ex.Length)
-	extentEnd := endPhyBlk * f.regFile.inode.blkSize // This is exclusive.
-
-	toRead := int(extentEnd - readStart)
-	if len(dst) < toRead {
-		toRead = len(dst)
-	}
-
-	n, _ := f.regFile.inode.dev.ReadAt(dst[:toRead], int64(readStart))
-	if n < toRead {
-		return n, syserror.EIO
-	}
-	return n, nil
-}