From 8f4278dcdc1767bad9a26315e5a180c7114b2eb4 Mon Sep 17 00:00:00 2001
From: Luke Shumaker <lukeshu@lukeshu.com>
Date: Sun, 17 Jul 2022 23:06:57 -0600
Subject: implement xattrs

---
 lib/btrfs/io4_fs.go                  |  6 +++-
 lib/btrfsprogs/btrfsinspect/mount.go | 59 ++++++++++++++++++++++++++++++++++--
 2 files changed, 62 insertions(+), 3 deletions(-)

diff --git a/lib/btrfs/io4_fs.go b/lib/btrfs/io4_fs.go
index d28e36f..65a7562 100644
--- a/lib/btrfs/io4_fs.go
+++ b/lib/btrfs/io4_fs.go
@@ -29,6 +29,7 @@ type BareInode struct {
 
 type FullInode struct {
 	BareInode
+	XAttrs     map[string]string
 	OtherItems []Item
 }
 
@@ -133,6 +134,7 @@ func (sv *Subvolume) LoadFullInode(inode ObjID) (*FullInode, error) {
 			BareInode: BareInode{
 				Inode: inode,
 			},
+			XAttrs: make(map[string]string),
 		}
 		items, err := sv.FS.TreeSearchAll(sv.TreeID, func(key Key, _ uint32) int {
 			return containers.NativeCmp(inode, key.ObjectID)
@@ -154,6 +156,9 @@ func (sv *Subvolume) LoadFullInode(inode ObjID) (*FullInode, error) {
 					continue
 				}
 				val.InodeItem = &itemBody
+			case btrfsitem.XATTR_ITEM_KEY:
+				itemBody := item.Body.(btrfsitem.DirEntry)
+				val.XAttrs[string(itemBody.Name)] = string(itemBody.Data)
 			default:
 				val.OtherItems = append(val.OtherItems, item)
 			}
@@ -233,7 +238,6 @@ func (ret *Dir) populate() {
 				continue
 			}
 			ret.ChildrenByIndex[index] = entry
-		//case btrfsitem.XATTR_ITEM_KEY:
 		default:
 			panic(fmt.Errorf("TODO: handle item type %v", item.Key.ItemType))
 		}
diff --git a/lib/btrfsprogs/btrfsinspect/mount.go b/lib/btrfsprogs/btrfsinspect/mount.go
index 05f3b9b..dbab7c7 100644
--- a/lib/btrfsprogs/btrfsinspect/mount.go
+++ b/lib/btrfsprogs/btrfsinspect/mount.go
@@ -411,9 +411,64 @@ func (sv *subvolume) ReadSymlink(_ context.Context, op *fuseops.ReadSymlinkOp) e
 	return nil
 }
 
-func (sv *subvolume) GetXattr(_ context.Context, op *fuseops.GetXattrOp) error { return syscall.ENOSYS }
 func (sv *subvolume) ListXattr(_ context.Context, op *fuseops.ListXattrOp) error {
-	return syscall.ENOSYS
+	if op.Inode == fuseops.RootInodeID {
+		inode, err := sv.GetRootInode()
+		if err != nil {
+			return err
+		}
+		op.Inode = fuseops.InodeID(inode)
+	}
+
+	fullInode, err := sv.LoadFullInode(btrfs.ObjID(op.Inode))
+	if err != nil {
+		return err
+	}
+
+	size := 0
+	for name := range fullInode.XAttrs {
+		size += len(name) + 1
+	}
+	if len(op.Dst) < size {
+		return syscall.ERANGE
+	}
+
+	op.BytesRead = size
+	n := 0
+	for _, name := range maps.SortedKeys(fullInode.XAttrs) {
+		n += copy(op.Dst[n:], name)
+		op.Dst[n] = 0
+		n++
+	}
+	return nil
+}
+
+func (sv *subvolume) GetXattr(_ context.Context, op *fuseops.GetXattrOp) error {
+	if op.Inode == fuseops.RootInodeID {
+		inode, err := sv.GetRootInode()
+		if err != nil {
+			return err
+		}
+		op.Inode = fuseops.InodeID(inode)
+	}
+
+	fullInode, err := sv.LoadFullInode(btrfs.ObjID(op.Inode))
+	if err != nil {
+		return err
+	}
+
+	val, ok := fullInode.XAttrs[op.Name]
+	if !ok {
+		return syscall.ENODATA
+	}
+
+	if len(op.Dst) < len(val) {
+		return syscall.ERANGE
+	}
+
+	op.BytesRead = len(val)
+	copy(op.Dst, val)
+	return nil
 }
 
 func (sv *subvolume) Destroy() {}
-- 
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