ext: Add ext2 and ext3 tiny images.

PiperOrigin-RevId: 259657917

4 files changed, 18 insertions, 9 deletions

diff --git a/pkg/sentry/fs/ext/assets/README.md b/pkg/sentry/fs/ext/assets/README.md
index b6eac4f40..6f1e81b3a 100644
--- a/pkg/sentry/fs/ext/assets/README.md
+++ b/pkg/sentry/fs/ext/assets/README.md
@@ -1,19 +1,21 @@
-### Tiny Ext4 Image
+### Tiny Ext(2/3/4) Images
 
-The image is of size 64Kb which supports 64 1k blocks and 16 inodes. This is the
-smallest size mkfs.ext4 works with.
+The images are of size 64Kb which supports 64 1k blocks and 16 inodes. This is
+the smallest size mkfs.ext(2/3/4) works with.
 
-This image was generated using the following commands.
+These images were generated using the following commands.
 
 ```bash
-fallocate -l 64K tiny.ext4
-mkfs.ext4 -j tiny.ext4
+fallocate -l 64K tiny.ext$VERSION
+mkfs.ext$VERSION -j tiny.ext$VERSION
 ```
 
+where `VERSION` is `2`, `3` or `4`.
+
 You can mount it using:
 
 ```bash
-sudo mount -o loop tiny.ext4 $MOUNTPOINT
+sudo mount -o loop tiny.ext$VERSION $MOUNTPOINT
 ```
 
 `file.txt`, `bigfile.txt` and `symlink.txt` were added to this image by just
@@ -21,8 +23,14 @@ mounting it and copying (while preserving links) those files to the mountpoint
 directory using:
 
 ```bash
-sudo cp -P {file.txt,symlink.txt,bigfile.txt} $MOUNTPOINT/
+sudo cp -P {file.txt,symlink.txt,bigfile.txt} $MOUNTPOINT
 ```
 
 The files in this directory mirror the contents and organisation of the files
 stored in the image.
+
+You can umount the filesystem using:
+
+```bash
+sudo umount $MOUNTPOINT
+```
diff --git a/pkg/sentry/fs/ext/assets/tiny.ext2 b/pkg/sentry/fs/ext/assets/tiny.ext2
new file mode 100644
index 000000000..381ade9bf
--- /dev/null
+++ b/pkg/sentry/fs/ext/assets/tiny.ext2
diff --git a/pkg/sentry/fs/ext/assets/tiny.ext3 b/pkg/sentry/fs/ext/assets/tiny.ext3
new file mode 100644
index 000000000..0e97a324c
--- /dev/null
+++ b/pkg/sentry/fs/ext/assets/tiny.ext3
diff --git a/pkg/sentry/fs/ext/extent_test.go b/pkg/sentry/fs/ext/extent_test.go
index c8c52f836..9e55187e5 100644
--- a/pkg/sentry/fs/ext/extent_test.go
+++ b/pkg/sentry/fs/ext/extent_test.go
@@ -145,7 +145,8 @@ func TestExtentTree(t *testing.T) {
 		t.Fatalf("inode.buildExtTree failed: %v", err)
 	}
 
-	if diff := cmp.Diff(&mockInode.root, node0, cmpopts.IgnoreUnexported(disklayout.ExtentNode{})); diff != "" {
+	opt := cmpopts.IgnoreUnexported(disklayout.ExtentIdx{}, disklayout.ExtentHeader{})
+	if diff := cmp.Diff(&mockInode.root, node0, opt); diff != "" {
 		t.Errorf("extent tree mismatch (-want +got):\n%s", diff)
 	}
 }