From 12ae127e0bf62281f7c6eae956656c5218154a50 Mon Sep 17 00:00:00 2001
From: Alex Denes <caskd@redxen.eu>
Date: Sun, 29 Sep 2024 16:48:48 +0000
Subject: [PATCH] ioctl & subvolume: Handle BTRFS_ROOT_SUBVOL_RDONLY as well
 for searches

---
 ioctl_h.go   | 15 ++++++++++-----
 subvolume.go |  3 +++
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/ioctl_h.go b/ioctl_h.go
index 769689b..d31db71 100644
--- a/ioctl_h.go
+++ b/ioctl_h.go
@@ -96,17 +96,21 @@ const subvolNameMax = 4039
 
 type SubvolFlags uint64
 
+// Match flags like GetFlags translates in fs/btrfs/ioctl.c `btrfs_ioctl_subvol_getflags`
+const subvolReadOnlyMask = (SubvolReadOnly | SubvolRootReadOnly)
+
 func (f SubvolFlags) ReadOnly() bool {
-	return f&SubvolReadOnly != 0
+	return f&subvolReadOnlyMask != 0
 }
 func (f SubvolFlags) String() string {
 	if f == 0 {
 		return "<nil>"
 	}
 	var out []string
-	if f&SubvolReadOnly != 0 {
+
+	if f.ReadOnly() {
 		out = append(out, "RO")
-		f = f & (^SubvolReadOnly)
+		f = f & (^subvolReadOnlyMask)
 	}
 	if f != 0 {
 		out = append(out, "0x"+strconv.FormatInt(int64(f), 16))
@@ -123,8 +127,9 @@ func (f SubvolFlags) String() string {
 // - BTRFS_IOC_SUBVOL_GETFLAGS
 // - BTRFS_IOC_SUBVOL_SETFLAGS
 const (
-	subvolCreateAsync   = SubvolFlags(1 << 0)
-	SubvolReadOnly      = SubvolFlags(1 << 1)
+	subvolCreateAsync   = SubvolFlags(1 << 0) // deprecated in 5.7
+	SubvolRootReadOnly  = SubvolFlags(1 << 0) // BTRFS_ROOT_SUBVOL_RDONLY, only present in search result copies
+	SubvolReadOnly      = SubvolFlags(1 << 1) // BTRFS_SUBVOL_RDONLY
 	subvolQGroupInherit = SubvolFlags(1 << 2)
 )
 
diff --git a/subvolume.go b/subvolume.go
index 0d2d808..deed0af 100644
--- a/subvolume.go
+++ b/subvolume.go
@@ -253,6 +253,8 @@ func listSubVolumes(f *os.File, filter func(SubvolInfo) bool) (map[objectID]Subv
 type SubvolInfo struct {
 	RootID uint64
 
+	Flags SubvolFlags
+
 	UUID         UUID
 	ParentUUID   UUID
 	ReceivedUUID UUID
@@ -274,6 +276,7 @@ func (s *SubvolInfo) fillFromItem(it *rootItem) {
 	s.UUID = it.UUID
 	s.ReceivedUUID = it.ReceivedUUID
 	s.ParentUUID = it.ParentUUID
+	s.Flags = SubvolFlags(it.Flags)
 
 	s.CTime = it.CTime
 	s.OTime = it.OTime