From 4b499063acd64c7d5249a110d8eb7dc23d7b3e2b Mon Sep 17 00:00:00 2001
From: Scott Lamb <slamb@slamb.org>
Date: Wed, 21 Jul 2021 10:03:49 -0700
Subject: [PATCH] fsck: no emergency.target on nofail mounts

Also describe failure behavior more precisely in the manpage.
Fixes #20237.
---
 man/systemd-fsck@.service.xml      | 15 ++++++++++++---
 src/fsck/fsck.c                    |  7 ++-----
 units/systemd-fsck-root.service.in |  2 ++
 3 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/man/systemd-fsck@.service.xml b/man/systemd-fsck@.service.xml
index 035382913f3..aa0d8b12aed 100644
--- a/man/systemd-fsck@.service.xml
+++ b/man/systemd-fsck@.service.xml
@@ -55,9 +55,18 @@
     the filesystem should actually be checked based on the time since
     last check, number of mounts, unclean unmount, etc.</para>
 
-    <para>If a file system check fails for a service without
-    <option>nofail</option>, emergency mode is activated, by isolating
-    to <filename>emergency.target</filename>.</para>
+    <para><filename>systemd-fsck-root.service</filename> will activate
+    <filename>reboot.target</filename> if <filename>/sbin/fsck</filename>
+    returns the "System should reboot" condition, or
+    <filename>emergency.target</filename> if <filename>/sbin/fsck</filename>
+    returns the "Filesystem errors left uncorrected" condition.</para>
+
+    <para><filename>systemd-fsck@.service</filename> will fail if
+    <filename>/sbin/fsck</filename> returns with either "System should reboot"
+    or "Filesystem errors left uncorrected" conditions. For filesystems
+    listed in <filename>/etc/fstab</filename> without <literal>nofail</literal>
+    or <literal>noauto</literal> options, <literal>local-fs.target</literal>
+    will then activate <filename>emergency.target</filename>.</para>
   </refsect1>
 
   <refsect1>
diff --git a/src/fsck/fsck.c b/src/fsck/fsck.c
index cd7adfaeb96..745d01ff502 100644
--- a/src/fsck/fsck.c
+++ b/src/fsck/fsck.c
@@ -52,7 +52,7 @@ static void start_target(const char *target, const char *mode) {
                 return;
         }
 
-        log_info("Running request %s/start/replace", target);
+        log_info("Running request %s/start/%s", target, mode);
 
         /* Start these units only if we can replace base.target with it */
         r = sd_bus_call_method(bus,
@@ -412,10 +412,7 @@ static int run(int argc, char *argv[]) {
                         /* System should be rebooted. */
                         start_target(SPECIAL_REBOOT_TARGET, "replace-irreversibly");
                         return -EINVAL;
-                } else if (exit_status & (FSCK_SYSTEM_SHOULD_REBOOT | FSCK_ERRORS_LEFT_UNCORRECTED))
-                        /* Some other problem */
-                        start_target(SPECIAL_EMERGENCY_TARGET, "replace");
-                else
+                } else if (!(exit_status & (FSCK_SYSTEM_SHOULD_REBOOT | FSCK_ERRORS_LEFT_UNCORRECTED)))
                         log_warning("Ignoring error.");
         }
 
diff --git a/units/systemd-fsck-root.service.in b/units/systemd-fsck-root.service.in
index 6897f13159e..8378df84c71 100644
--- a/units/systemd-fsck-root.service.in
+++ b/units/systemd-fsck-root.service.in
@@ -14,6 +14,8 @@ DefaultDependencies=no
 Conflicts=shutdown.target
 Before=local-fs.target shutdown.target
 ConditionPathIsReadWrite=!/
+OnFailure=emergency.target
+OnFailureJobMode=replace-irreversibly
 
 [Service]
 Type=oneshot