1 files changed, 75 insertions, 0 deletions
diff --git a/pkg/sentry/fs/ext/disklayout/superblock_32.go b/pkg/sentry/fs/ext/disklayout/superblock_32.go
new file mode 100644
index 000000000..587e4afaa
--- /dev/null
+++ b/pkg/sentry/fs/ext/disklayout/superblock_32.go
@@ -0,0 +1,75 @@
+// 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 disklayout
+
+// SuperBlock32Bit implements SuperBlock and represents the 32-bit version of
+// the ext4_super_block struct in fs/ext4/ext4.h.
+type SuperBlock32Bit struct {
+	// We embed the old superblock struct here because the 32-bit version is just
+	// an extension of the old version.
+	SuperBlockOld
+
+	FirstInode         uint32
+	InodeSizeRaw       uint16
+	BlockGroupNumber   uint16
+	FeatureCompat      uint32
+	FeatureIncompat    uint32
+	FeatureRoCompat    uint32
+	UUID               [16]byte
+	VolumeName         [16]byte
+	LastMounted        [64]byte
+	AlgoUsageBitmap    uint32
+	PreallocBlocks     uint8
+	PreallocDirBlocks  uint8
+	ReservedGdtBlocks  uint16
+	JournalUUID        [16]byte
+	JournalInum        uint32
+	JournalDev         uint32
+	LastOrphan         uint32
+	HashSeed           [4]uint32
+	DefaultHashVersion uint8
+	JnlBackupType      uint8
+	BgDescSizeRaw      uint16
+	DefaultMountOpts   uint32
+	FirstMetaBg        uint32
+	MkfsTime           uint32
+	JnlBlocks          [17]uint32
+}
+
+// Compiles only if SuperBlock32Bit implements SuperBlock.
+var _ SuperBlock = (*SuperBlock32Bit)(nil)
+
+// Only override methods which change based on the additional fields above.
+// Not overriding SuperBlock.BgDescSize because it would still return 32 here.
+
+// InodeSize implements SuperBlock.InodeSize.
+func (sb *SuperBlock32Bit) InodeSize() uint16 {
+	return sb.InodeSizeRaw
+}
+
+// CompatibleFeatures implements SuperBlock.CompatibleFeatures.
+func (sb *SuperBlock32Bit) CompatibleFeatures() CompatFeatures {
+	return CompatFeaturesFromInt(sb.FeatureCompat)
+}
+
+// IncompatibleFeatures implements SuperBlock.IncompatibleFeatures.
+func (sb *SuperBlock32Bit) IncompatibleFeatures() IncompatFeatures {
+	return IncompatFeaturesFromInt(sb.FeatureIncompat)
+}
+
+// ReadOnlyCompatibleFeatures implements SuperBlock.ReadOnlyCompatibleFeatures.
+func (sb *SuperBlock32Bit) ReadOnlyCompatibleFeatures() RoCompatFeatures {
+	return RoCompatFeaturesFromInt(sb.FeatureRoCompat)
+}