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authorLuke Shumaker <lukeshu@lukeshu.com>2023-03-17 18:38:14 -0400
committerLuke Shumaker <lukeshu@lukeshu.com>2023-03-17 18:38:14 -0400
commit0f85e72d1331b49b52925d6cc5ad083a0376104c (patch)
tree9ba66e893d6f66096f6b06284d09c8eb3e50facc /lib/btrfs/btrfsitem/item_blockgroup.go
parentc0f33186aa7a8903c5e7406024f13fad48cd14e3 (diff)
parent1ea26f04701fa66e36b058f3efb3a6c7059cdc5c (diff)
Merge branch 'lukeshu/lint'
Diffstat (limited to 'lib/btrfs/btrfsitem/item_blockgroup.go')
-rw-r--r--lib/btrfs/btrfsitem/item_blockgroup.go16
1 files changed, 14 insertions, 2 deletions
diff --git a/lib/btrfs/btrfsitem/item_blockgroup.go b/lib/btrfs/btrfsitem/item_blockgroup.go
index ae0ca12..dc561bd 100644
--- a/lib/btrfs/btrfsitem/item_blockgroup.go
+++ b/lib/btrfs/btrfsitem/item_blockgroup.go
@@ -10,8 +10,20 @@ import (
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
)
-// key.objectid = logical_addr
-// key.offset = size of chunk
+// A BlockGroup tracks allocation of the logical address space.
+//
+// Compare with:
+// - DevExtents, which track allocation of the physical address space.
+// - Chunks, which map logical addresses to physical addresses.
+//
+// The relationship between the three is
+//
+// DevExtent---[many:one]---Chunk---[one:one]---BlockGroup
+//
+// Key:
+//
+// key.objectid = logical_addr
+// key.offset = size of chunk
type BlockGroup struct { // trivial BLOCK_GROUP_ITEM=192
Used int64 `bin:"off=0, siz=8"`
ChunkObjectID btrfsprim.ObjID `bin:"off=8, siz=8"` // always FIRST_CHUNK_TREE_OBJECTID