man/systemd-fstab-generator.xml

@@ -82,20 +82,9 @@
       <varlistentry>
         <term><varname>root=</varname></term>
 
-        <listitem><para>Configures the operating system's root filesystem to mount when running in the
-        initrd. This accepts a device node path (usually <filename>/dev/disk/by-uuid/…</filename> or
-        <filename>/dev/disk/by-label/…</filename> or similar), or the special values <literal>gpt-auto</literal>
-        and <literal>tmpfs</literal>.</para>
-
-        <para>Use <literal>gpt-auto</literal> to explicitly request automatic root file system discovery via
-        <citerefentry><refentrytitle>systemd-gpt-auto-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
-
-        <para>Use <literal>tmpfs</literal> in order to mount a <citerefentry
-        project='man-pages'><refentrytitle>tmpfs</refentrytitle><manvolnum>5</manvolnum></citerefentry> file
-        system as root file system of the OS. This is useful in combination with
-        <varname>mount.usr=</varname> (see below) in order to combine a volatile root file system with a
-        separate, immutable <filename>/usr/</filename> file system. Also see
-        <varname>systemd.volatile=</varname> below.</para></listitem>
+        <listitem><para>Takes the root filesystem to mount in the
+        initrd. <varname>root=</varname> is honored by the
+        initrd.</para></listitem>
       </varlistentry>
 
       <varlistentry>
@@ -204,19 +193,10 @@
         or any other resources stored in the root file system are physically removed. It's thus safe to boot a system
         that is normally operated in non-volatile mode temporarily into volatile mode, without losing data.</para>
 
-        <para>Note that with the exception of <literal>overlay</literal> mode, enabling this setting will
-        only work correctly on operating systems that can boot up with only <filename>/usr/</filename>
-        mounted, and are able to automatically populate <filename>/etc/</filename>, and also
-        <filename>/var/</filename> in case of <literal>systemd.volatile=yes</literal>.</para>
-
-        <para>Also see <varname>root=tmpfs</varname> above, for a method to combine a
-        <literal>tmpfs</literal> file system with a regular <filename>/usr/</filename> file system (as
-        configured via <varname>mount.usr=</varname>). The main distinction between
-        <varname>systemd.volatile=yes</varname>, and <varname>root=tmpfs</varname> in combination
-        <varname>mount.usr=</varname> is that the former operates on top of a regular root file system and
-        temporarily obstructs the files and directories above its <filename>/usr/</filename> subdirectory,
-        while the latter does not hide any files, but simply mounts a unpopulated tmpfs as root file system
-        and combines it with a user picked <filename>/usr/</filename> file system.</para></listitem>
+        <para>Note that with the exception of <literal>overlay</literal> mode, enabling this setting will only work
+        correctly on operating systems that can boot up with only <filename>/usr/</filename> mounted, and are able to
+        automatically populate <filename>/etc/</filename>, and also <filename>/var/</filename> in case of
+        <literal>systemd.volatile=yes</literal>.</para></listitem>
       </varlistentry>
 
       <varlistentry>
@@ -238,7 +218,6 @@
       <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
       <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
       <citerefentry><refentrytitle>systemd-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
-      <citerefentry><refentrytitle>systemd-gpt-auto-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
       <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>
     </para>
   </refsect1>

src/basic/time-util.h

@@ -155,14 +155,16 @@ usec_t jiffies_to_usec(uint32_t jiffies);
 bool in_utc_timezone(void);
 
 static inline usec_t usec_add(usec_t a, usec_t b) {
+        usec_t c;
 
         /* Adds two time values, and makes sure USEC_INFINITY as input results as USEC_INFINITY in output, and doesn't
          * overflow. */
 
-        if (a > USEC_INFINITY - b) /* overflow check */
+        c = a + b;
+        if (c < a || c < b) /* overflow check */
                 return USEC_INFINITY;
 
-        return a + b;
+        return c;
 }
 
 static inline usec_t usec_sub_unsigned(usec_t timestamp, usec_t delta) {

src/fstab-generator/fstab-generator.c

@@ -671,8 +671,7 @@ static int parse_fstab(bool initrd) {
 
 static int add_sysroot_mount(void) {
         _cleanup_free_ char *what = NULL;
-        const char *opts, *fstype;
-        bool default_rw;
+        const char *opts;
         int r;
 
         if (isempty(arg_root_what)) {
@@ -692,29 +691,12 @@ static int add_sysroot_mount(void) {
                 return 0;
         }
 
-        if (streq(arg_root_what, "tmpfs")) {
-                /* If root=tmpfs is specified, then take this as shortcut for a writable tmpfs mount as root */
-
-                what = strdup("rootfs"); /* just a pretty name, to show up in /proc/self/mountinfo */
-                if (!what)
-                        return log_oom();
-
-                fstype = arg_root_fstype ?: "tmpfs"; /* tmpfs, unless overriden */
-
-                default_rw = true; /* writable, unless overriden */;
-        } else {
-
         what = fstab_node_to_udev_node(arg_root_what);
         if (!what)
                 return log_oom();
 
-                fstype = arg_root_fstype; /* if not specified explicitly, don't default to anything here */
-
-                default_rw = false; /* read-only, unless overriden */
-        }
-
         if (!arg_root_options)
-                opts = arg_root_rw > 0 || (arg_root_rw < 0 && default_rw) ? "rw" : "ro";
+                opts = arg_root_rw > 0 ? "rw" : "ro";
         else if (arg_root_rw >= 0 ||
                  !fstab_test_option(arg_root_options, "ro\0" "rw\0"))
                 opts = strjoina(arg_root_options, ",", arg_root_rw > 0 ? "rw" : "ro");
@@ -733,7 +715,7 @@ static int add_sysroot_mount(void) {
                          what,
                          "/sysroot",
                          NULL,
-                         fstype,
+                         arg_root_fstype,
                          opts,
                          is_device_path(what) ? 1 : 0, /* passno */
                          0,                            /* makefs off, growfs off, noauto off, nofail off, automount off */