From 017d6b693f9a8bfc64f9ba2afa9526b47e03c871 Mon Sep 17 00:00:00 2001
From: Kir Kolyshkin <kolyshkin@gmail.com>
Date: Tue, 13 May 2025 19:46:28 -0700
Subject: [PATCH] criu: improve prepareCriuRestoreMounts

1. Replace the big "if !" block with the if block and continue,
   simplifying the code flow.

2. Move comments closer to the code, improving readability.

This commit is best reviewed with --ignore-all-space or similar.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
(cherry picked from commit 0c93d41c65b6a1055e945d1d3e56943b07b8405b)
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
---
 libcontainer/criu_linux.go | 45 +++++++++++++++++++-------------------
 1 file changed, 23 insertions(+), 22 deletions(-)

diff --git a/libcontainer/criu_linux.go b/libcontainer/criu_linux.go
index 8cd8fa5ae..86de1c2d4 100644
--- a/libcontainer/criu_linux.go
+++ b/libcontainer/criu_linux.go
@@ -572,9 +572,6 @@ func (c *Container) prepareCriuRestoreMounts(mounts []*configs.Mount) error {
 			tmpfs = append(tmpfs, m.Destination)
 		}
 	}
-	// Now go through all mounts and create the mountpoints
-	// if the mountpoints are not on a tmpfs, as CRIU will
-	// restore the complete tmpfs content from its checkpoint.
 	umounts := []string{}
 	defer func() {
 		for _, u := range umounts {
@@ -590,28 +587,32 @@ func (c *Container) prepareCriuRestoreMounts(mounts []*configs.Mount) error {
 			})
 		}
 	}()
+	// Now go through all mounts and create the required mountpoints.
 	for _, m := range mounts {
-		if !isPathInPrefixList(m.Destination, tmpfs) {
-			if err := c.makeCriuRestoreMountpoints(m); err != nil {
+		// If the mountpoint is on a tmpfs, skip it as CRIU will
+		// restore the complete tmpfs content from its checkpoint.
+		if isPathInPrefixList(m.Destination, tmpfs) {
+			continue
+		}
+		if err := c.makeCriuRestoreMountpoints(m); err != nil {
+			return err
+		}
+		// If the mount point is a bind mount, we need to mount
+		// it now so that runc can create the necessary mount
+		// points for mounts in bind mounts.
+		// This also happens during initial container creation.
+		// Without this CRIU restore will fail
+		// See: https://github.com/opencontainers/runc/issues/2748
+		// It is also not necessary to order the mount points
+		// because during initial container creation mounts are
+		// set up in the order they are configured.
+		if m.Device == "bind" {
+			if err := utils.WithProcfd(c.config.Rootfs, m.Destination, func(dstFd string) error {
+				return mountViaFds(m.Source, nil, m.Destination, dstFd, "", unix.MS_BIND|unix.MS_REC, "")
+			}); err != nil {
 				return err
 			}
-			// If the mount point is a bind mount, we need to mount
-			// it now so that runc can create the necessary mount
-			// points for mounts in bind mounts.
-			// This also happens during initial container creation.
-			// Without this CRIU restore will fail
-			// See: https://github.com/opencontainers/runc/issues/2748
-			// It is also not necessary to order the mount points
-			// because during initial container creation mounts are
-			// set up in the order they are configured.
-			if m.Device == "bind" {
-				if err := utils.WithProcfd(c.config.Rootfs, m.Destination, func(dstFd string) error {
-					return mountViaFds(m.Source, nil, m.Destination, dstFd, "", unix.MS_BIND|unix.MS_REC, "")
-				}); err != nil {
-					return err
-				}
-				umounts = append(umounts, m.Destination)
-			}
+			umounts = append(umounts, m.Destination)
 		}
 	}
 	return nil