From b78fe1835fed316bd8e9e51c91fcc05422330490 Mon Sep 17 00:00:00 2001
From: Luke Shumaker <lukeshu@lukeshu.com>
Date: Thu, 30 Jun 2022 04:14:55 -0600
Subject: lock sizes, use blockgroups

---
 pkg/btrfs/btrfsvol/chunk.go | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

(limited to 'pkg/btrfs/btrfsvol/chunk.go')

diff --git a/pkg/btrfs/btrfsvol/chunk.go b/pkg/btrfs/btrfsvol/chunk.go
index e53265f..146193d 100644
--- a/pkg/btrfs/btrfsvol/chunk.go
+++ b/pkg/btrfs/btrfsvol/chunk.go
@@ -9,12 +9,15 @@ import (
 
 // logical => []physical
 type chunkMapping struct {
-	LAddr  LogicalAddr
-	PAddrs []QualifiedPhysicalAddr
-	Size   AddrDelta
-	Flags  *BlockGroupFlags
+	LAddr      LogicalAddr
+	PAddrs     []QualifiedPhysicalAddr
+	Size       AddrDelta
+	SizeLocked bool
+	Flags      *BlockGroupFlags
 }
 
+type ChunkMapping = chunkMapping
+
 // return -1 if 'a' is wholly to the left of 'b'
 // return 0 if there is some overlap between 'a' and 'b'
 // return 1 if 'a is wholly to the right of 'b'
@@ -51,6 +54,15 @@ func (a chunkMapping) union(rest ...chunkMapping) (chunkMapping, error) {
 		LAddr: beg,
 		Size:  end.Sub(beg),
 	}
+	for _, chunk := range chunks {
+		if chunk.SizeLocked {
+			ret.SizeLocked = true
+			if ret.Size != chunk.Size {
+				return chunkMapping{}, fmt.Errorf("member chunk has locked size=%v, but union would have size=%v",
+					chunk.Size, ret.Size)
+			}
+		}
+	}
 	// figure out the physical stripes (.PAddrs)
 	paddrs := make(map[QualifiedPhysicalAddr]struct{})
 	for _, chunk := range chunks {
-- 
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