Define sizes for extent headers and entries separately to improve clarity.

PiperOrigin-RevId: 288799694

2 files changed, 10 insertions, 6 deletions

diff --git a/pkg/sentry/fsimpl/ext/disklayout/extent.go b/pkg/sentry/fsimpl/ext/disklayout/extent.go
index 567523d32..4110649ab 100644
--- a/pkg/sentry/fsimpl/ext/disklayout/extent.go
+++ b/pkg/sentry/fsimpl/ext/disklayout/extent.go
@@ -29,8 +29,12 @@ package disklayout
 //       byte (i * sb.BlockSize()) to ((i+1) * sb.BlockSize()).
 
 const (
-	// ExtentStructsSize is the size of all the three extent on-disk structs.
-	ExtentStructsSize = 12
+	// ExtentHeaderSize is the size of the header of an extent tree node.
+	ExtentHeaderSize = 12
+
+	// ExtentEntrySize is the size of an entry in an extent tree node.
+	// This size is the same for both leaf and internal nodes.
+	ExtentEntrySize = 12
 
 	// ExtentMagic is the magic number which must be present in the header.
 	ExtentMagic = 0xf30a
@@ -57,7 +61,7 @@ type ExtentNode struct {
 	Entries []ExtentEntryPair
 }
 
-// ExtentEntry reprsents an extent tree node entry. The entry can either be
+// ExtentEntry represents an extent tree node entry. The entry can either be
 // an ExtentIdx or Extent itself. This exists to simplify navigation logic.
 type ExtentEntry interface {
 	// FileBlock returns the first file block number covered by this entry.
diff --git a/pkg/sentry/fsimpl/ext/disklayout/extent_test.go b/pkg/sentry/fsimpl/ext/disklayout/extent_test.go
index b0fad9b71..8762b90db 100644
--- a/pkg/sentry/fsimpl/ext/disklayout/extent_test.go
+++ b/pkg/sentry/fsimpl/ext/disklayout/extent_test.go
@@ -21,7 +21,7 @@ import (
 // TestExtentSize tests that the extent structs are of the correct
 // size.
 func TestExtentSize(t *testing.T) {
-	assertSize(t, ExtentHeader{}, ExtentStructsSize)
-	assertSize(t, ExtentIdx{}, ExtentStructsSize)
-	assertSize(t, Extent{}, ExtentStructsSize)
+	assertSize(t, ExtentHeader{}, ExtentHeaderSize)
+	assertSize(t, ExtentIdx{}, ExtentEntrySize)
+	assertSize(t, Extent{}, ExtentEntrySize)
 }