From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 2 Jun 2023 09:42:08 +0000 (+0200)
Subject: detach-loopback: also don't bother detaching loopback block device /usr/ is running off
X-Git-Tag: v254-rc1~299^2~1
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=9959797dbf2f14d4c7131e81e748f4081c9bbb9c;p=thirdparty%2Fsystemd.git

detach-loopback: also don't bother detaching loopback block device /usr/ is running off

While we are at it, let's also clean this up a bit: unlike DM/MD devices
loopback devices are likely partitioned, hence trace the block device
through the partition layer and LUKS.
---

diff --git a/src/shutdown/detach-loopback.c b/src/shutdown/detach-loopback.c
index ceac74223c7..f45960856bc 100644
--- a/src/shutdown/detach-loopback.c
+++ b/src/shutdown/detach-loopback.c
@@ -175,15 +175,21 @@ static int delete_loopback(const char *device) {
 
 static int loopback_points_list_detach(LoopbackDevice **head, bool *changed, bool last_try) {
         int n_failed = 0, r;
-        dev_t rootdev = 0;
+        dev_t rootdev = 0, usrdev = 0;
 
         assert(head);
         assert(changed);
 
-        (void) get_block_device("/", &rootdev);
+        (void) get_block_device_harder("/", &rootdev);
+        (void) block_get_whole_disk(rootdev, &rootdev);
+
+        (void) get_block_device_harder("/usr", &usrdev);
+        (void) block_get_whole_disk(usrdev, &usrdev);
 
         LIST_FOREACH(loopback_device, m, *head) {
-                if (major(rootdev) != 0 && rootdev == m->devnum) {
+                if ((major(rootdev) != 0 && rootdev == m->devnum) ||
+                    (major(usrdev) != 0 && usrdev == m->devnum)) {
+                        log_debug("Not detaching loopback device %s that backs the OS itself, skipping.", m->path);
                         n_failed++;
                         continue;
                 }