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authorLuke Shumaker <lukeshu@lukeshu.com>2023-03-17 01:46:40 -0400
committerLuke Shumaker <lukeshu@lukeshu.com>2023-03-17 02:51:43 -0400
commitc30c43f3690931218b88680b337d11a57a2fdc45 (patch)
treea682afa37eaa5a5cee8f8b7a587edc7a40372355 /lib/btrfs/btrfsitem/item_blockgroup.go
parente082cfb3b8f8226067078cc410e4997fd1cf14df (diff)
tree-wide: Ensure that all existing type doc comments follow the expected format
This is a notable improvement in the docs for btrfsitem.
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