diff options
Diffstat (limited to 'pkg/sentry/fs/ext/extent_file.go')
| -rw-r--r-- | pkg/sentry/fs/ext/extent_file.go | 25 |
1 files changed, 11 insertions, 14 deletions
diff --git a/pkg/sentry/fs/ext/extent_file.go b/pkg/sentry/fs/ext/extent_file.go index 882300d96..aa4102dbb 100644 --- a/pkg/sentry/fs/ext/extent_file.go +++ b/pkg/sentry/fs/ext/extent_file.go @@ -36,7 +36,7 @@ type extentFile struct { var _ fileReader = (*extentFile)(nil) // Read implements fileReader.getFileReader. -func (f *extentFile) getFileReader(dev io.ReadSeeker, blkSize uint64, offset uint64) io.Reader { +func (f *extentFile) getFileReader(dev io.ReaderAt, blkSize uint64, offset uint64) io.Reader { return &extentReader{ dev: dev, file: f, @@ -47,10 +47,8 @@ func (f *extentFile) getFileReader(dev io.ReadSeeker, blkSize uint64, offset uin // newExtentFile is the extent file constructor. It reads the entire extent // tree into memory. -// -// Preconditions: Must hold the mutex of the filesystem containing dev. // TODO(b/134676337): Build extent tree on demand to reduce memory usage. -func newExtentFile(dev io.ReadSeeker, blkSize uint64, regFile regularFile) (*extentFile, error) { +func newExtentFile(dev io.ReaderAt, blkSize uint64, regFile regularFile) (*extentFile, error) { file := &extentFile{regFile: regFile} file.regFile.impl = file err := file.buildExtTree(dev, blkSize) @@ -65,10 +63,8 @@ func newExtentFile(dev io.ReadSeeker, blkSize uint64, regFile regularFile) (*ext // memory. Then it recursively builds the rest of the tree by reading it off // disk. // -// Preconditions: -// - Must hold the mutex of the filesystem containing dev. -// - Inode flag InExtents must be set. -func (f *extentFile) buildExtTree(dev io.ReadSeeker, blkSize uint64) error { +// Precondition: inode flag InExtents must be set. +func (f *extentFile) buildExtTree(dev io.ReaderAt, blkSize uint64) error { rootNodeData := f.regFile.inode.diskInode.Data() binary.Unmarshal(rootNodeData[:disklayout.ExtentStructsSize], binary.LittleEndian, &f.root.Header) @@ -110,9 +106,7 @@ func (f *extentFile) buildExtTree(dev io.ReadSeeker, blkSize uint64) error { // 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. -// -// Preconditions: Must hold the mutex of the filesystem containing dev. -func buildExtTreeFromDisk(dev io.ReadSeeker, entry disklayout.ExtentEntry, blkSize uint64) (*disklayout.ExtentNode, error) { +func buildExtTreeFromDisk(dev io.ReaderAt, entry disklayout.ExtentEntry, blkSize uint64) (*disklayout.ExtentNode, error) { var header disklayout.ExtentHeader off := entry.PhysicalBlock() * blkSize err := readFromDisk(dev, int64(off), &header) @@ -155,7 +149,7 @@ func buildExtTreeFromDisk(dev io.ReadSeeker, entry disklayout.ExtentEntry, blkSi // extentReader implements io.Reader which can traverse the extent tree and // read file data. This is not thread safe. type extentReader struct { - dev io.ReadSeeker + dev io.ReaderAt file *extentFile fileOff uint64 // Represents the current file offset being read from. blkSize uint64 @@ -247,9 +241,12 @@ func (r *extentReader) readFromExtent(ex *disklayout.Extent, dst []byte) (int, e toRead = len(dst) } - n, err := readFull(r.dev, int64(readStart), dst[:toRead]) + n, _ := r.dev.ReadAt(dst[:toRead], int64(readStart)) r.fileOff += uint64(n) - return n, err + if n < toRead { + return n, syserror.EIO + } + return n, nil } // fileBlock returns the file block number we are currently reading. |