ext: boilerplate code.

Renamed ext4 to ext since we are targeting ext(2/3/4).
Removed fs.go since we are targeting VFS2.
Added ext.go with filesystem struct.

PiperOrigin-RevId: 257689775

1 files changed, 94 insertions, 0 deletions

diff --git a/pkg/sentry/fs/ext/disklayout/superblock_64.go b/pkg/sentry/fs/ext/disklayout/superblock_64.go
new file mode 100644
index 000000000..a2c2278fb
--- /dev/null
+++ b/pkg/sentry/fs/ext/disklayout/superblock_64.go
@@ -0,0 +1,94 @@
+// 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
+
+// SuperBlock64Bit implements SuperBlock and represents the 64-bit version of
+// the ext4_super_block struct in fs/ext4/ext4.h. This sums up to be exactly
+// 1024 bytes (smallest possible block size) and hence the superblock always
+// fits in no more than one data block.
+type SuperBlock64Bit struct {
+	// We embed the 32-bit struct here because 64-bit version is just an extension
+	// of the 32-bit version.
+	SuperBlock32Bit
+
+	BlocksCountHi           uint32
+	ReservedBlocksCountHi   uint32
+	FreeBlocksCountHi       uint32
+	MinInodeSize            uint16
+	WantInodeSize           uint16
+	Flags                   uint32
+	RaidStride              uint16
+	MmpInterval             uint16
+	MmpBlock                uint64
+	RaidStripeWidth         uint32
+	LogGroupsPerFlex        uint8
+	ChecksumType            uint8
+	_                       uint16
+	KbytesWritten           uint64
+	SnapshotInum            uint32
+	SnapshotID              uint32
+	SnapshotRsrvBlocksCount uint64
+	SnapshotList            uint32
+	ErrorCount              uint32
+	FirstErrorTime          uint32
+	FirstErrorInode         uint32
+	FirstErrorBlock         uint64
+	FirstErrorFunction      [32]byte
+	FirstErrorLine          uint32
+	LastErrorTime           uint32
+	LastErrorInode          uint32
+	LastErrorLine           uint32
+	LastErrorBlock          uint64
+	LastErrorFunction       [32]byte
+	MountOpts               [64]byte
+	UserQuotaInum           uint32
+	GroupQuotaInum          uint32
+	OverheadBlocks          uint32
+	BackupBgs               [2]uint32
+	EncryptAlgos            [4]uint8
+	EncryptPwSalt           [16]uint8
+	LostFoundInode          uint32
+	ProjectQuotaInode       uint32
+	ChecksumSeed            uint32
+	WtimeHi                 uint8
+	MtimeHi                 uint8
+	MkfsTimeHi              uint8
+	LastCheckHi             uint8
+	FirstErrorTimeHi        uint8
+	LastErrorTimeHi         uint8
+	_                       [2]uint8
+	Encoding                uint16
+	EncodingFlags           uint16
+	_                       [95]uint32
+	Checksum                uint32
+}
+
+// Compiles only if SuperBlock64Bit implements SuperBlock.
+var _ SuperBlock = (*SuperBlock64Bit)(nil)
+
+// Only override methods which change based on the 64-bit feature.
+
+// BlocksCount implements SuperBlock.BlocksCount.
+func (sb *SuperBlock64Bit) BlocksCount() uint64 {
+	return (uint64(sb.BlocksCountHi) << 32) | uint64(sb.BlocksCountLo)
+}
+
+// FreeBlocksCount implements SuperBlock.FreeBlocksCount.
+func (sb *SuperBlock64Bit) FreeBlocksCount() uint64 {
+	return (uint64(sb.FreeBlocksCountHi) << 32) | uint64(sb.FreeBlocksCountLo)
+}
+
+// BgDescSize implements SuperBlock.BgDescSize.
+func (sb *SuperBlock64Bit) BgDescSize() uint16 { return sb.BgDescSizeRaw }