From 9361934479e4b606a079279e9cfbd0188333d975 Mon Sep 17 00:00:00 2001
From: Felicitas Pojtinger <felicitas@pojtinger.com>
Date: Wed, 10 Jul 2024 13:53:32 -0700
Subject: [PATCH] feature: Allow setting read/write, UUID and volume name
option for EXT4 file system writer
Signed-off-by: Felicitas Pojtinger <felicitas@pojtinger.com>
---
ext4/internal/compactext4/compact.go | 30 +++++++++++++++++++++++++++-
ext4/tar2ext4/tar2ext4.go | 21 +++++++++++++++++++
2 files changed, 50 insertions(+), 1 deletion(-)
diff --git a/ext4/internal/compactext4/compact.go b/ext4/internal/compactext4/compact.go
index 760b4dc4ef..90063fe9cb 100644
--- a/ext4/internal/compactext4/compact.go
+++ b/ext4/internal/compactext4/compact.go
@@ -31,6 +31,9 @@ type Writer struct {
initialized bool
supportInlineData bool
maxDiskSize int64
+ readWrite bool
+ uuid [16]byte
+ volumeName [16]byte
gdBlocks uint32
}
@@ -1141,6 +1144,25 @@ func MaximumDiskSize(size int64) Option {
}
}
+// ReadWrite instructs the writer to not mark the file system as write-protected.
+func ReadWrite(w *Writer) {
+ w.readWrite = true
+}
+
+// UUID instructs the writer to set the UUID.
+func UUID(uuid [16]byte) Option {
+ return func(w *Writer) {
+ w.uuid = uuid
+ }
+}
+
+// VolumeName instructs the writer to set the volume name.
+func VolumeName(volumeName [16]byte) Option {
+ return func(w *Writer) {
+ w.volumeName = volumeName
+ }
+}
+
func (w *Writer) init() error {
// Skip the defective block inode.
w.inodes = make([]*inode, 1, 32)
@@ -1311,6 +1333,10 @@ func (w *Writer) Close() error {
// Write the super block
var blk [BlockSize]byte
b := bytes.NewBuffer(blk[:1024])
+ featureRoCompat := format.RoCompatLargeFile | format.RoCompatHugeFile | format.RoCompatExtraIsize
+ if !w.readWrite {
+ featureRoCompat |= format.RoCompatReadonly
+ }
sb := &format.SuperBlock{
InodesCount: inodesPerGroup * groups,
BlocksCountLow: diskSize,
@@ -1332,10 +1358,12 @@ func (w *Writer) Close() error {
InodeSize: inodeSize,
FeatureCompat: format.CompatSparseSuper2 | format.CompatExtAttr,
FeatureIncompat: format.IncompatFiletype | format.IncompatExtents | format.IncompatFlexBg,
- FeatureRoCompat: format.RoCompatLargeFile | format.RoCompatHugeFile | format.RoCompatExtraIsize | format.RoCompatReadonly,
+ FeatureRoCompat: featureRoCompat,
MinExtraIsize: extraIsize,
WantExtraIsize: extraIsize,
LogGroupsPerFlex: 31,
+ UUID: w.uuid,
+ VolumeName: w.volumeName,
}
if w.supportInlineData {
sb.FeatureIncompat |= format.IncompatInlineData
diff --git a/ext4/tar2ext4/tar2ext4.go b/ext4/tar2ext4/tar2ext4.go
index 5af6bc21bf..479034a3a7 100644
--- a/ext4/tar2ext4/tar2ext4.go
+++ b/ext4/tar2ext4/tar2ext4.go
@@ -75,6 +75,27 @@ func MaximumDiskSize(size int64) Option {
}
}
+// ReadWrite instructs the writer to not mark the file system as write-protected.
+func ReadWrite() Option {
+ return func(p *params) {
+ p.ext4opts = append(p.ext4opts, compactext4.ReadWrite)
+ }
+}
+
+// UUID instructs the writer to set the UUID.
+func UUID(uuid [16]byte) Option {
+ return func(p *params) {
+ p.ext4opts = append(p.ext4opts, compactext4.UUID(uuid))
+ }
+}
+
+// VolumeName instructs the writer to set the volume name.
+func VolumeName(volumeName [16]byte) Option {
+ return func(p *params) {
+ p.ext4opts = append(p.ext4opts, compactext4.VolumeName(volumeName))
+ }
+}
+
const (
whiteoutPrefix = ".wh."
opaqueWhiteout = ".wh..wh..opq"