fstab-generator: add x-systemd.mount-timeout (#4603)

This adds a new systemd fstab option x-systemd.mount-timeout. The option
adds a timeout value that specifies how long systemd waits for the mount
command to finish. It allows to mount huge btrfs volumes without issues.

This is equivalent to adding option TimeoutSec= to [Mount] section in a
mount unit file.

fixes #4055

2 files changed, 37 insertions, 3 deletions

diff --git a/man/systemd.mount.xml b/man/systemd.mount.xml
index b0f156f6df..68ff6f8f1c 100644
--- a/man/systemd.mount.xml
+++ b/man/systemd.mount.xml
@@ -241,6 +241,25 @@
       </varlistentry>
 
       <varlistentry>
+        <term><option>x-systemd.mount-timeout=</option></term>
+
+        <listitem><para>Configure how long systemd should wait for the
+        mount command to finish before giving up on an entry from
+        <filename>/etc/fstab</filename>. Specify a time in seconds or
+        explicitly append a unit such as <literal>s</literal>,
+        <literal>min</literal>, <literal>h</literal>,
+        <literal>ms</literal>.</para>
+
+        <para>Note that this option can only be used in
+        <filename>/etc/fstab</filename>, and will be
+        ignored when part of the <varname>Options=</varname>
+        setting in a unit file.</para>
+
+        <para>See <varname>TimeoutSec=</varname> below for
+        details.</para>
+        </listitem>
+      </varlistentry>
+      <varlistentry>
         <term><option>noauto</option></term>
         <term><option>auto</option></term>
 
diff --git a/src/fstab-generator/fstab-generator.c b/src/fstab-generator/fstab-generator.c
index 46507de937..f6a912ae06 100644
--- a/src/fstab-generator/fstab-generator.c
+++ b/src/fstab-generator/fstab-generator.c
@@ -141,13 +141,14 @@ static bool mount_in_initrd(struct mntent *me) {
                streq(me->mnt_dir, "/usr");
 }
 
-static int write_idle_timeout(FILE *f, const char *where, const char *opts) {
+static int write_timeout(FILE *f, const char *where, const char *opts,
+                const char *filter, const char *variable) {
         _cleanup_free_ char *timeout = NULL;
         char timespan[FORMAT_TIMESPAN_MAX];
         usec_t u;
         int r;
 
-        r = fstab_filter_options(opts, "x-systemd.idle-timeout\0", NULL, &timeout, NULL);
+        r = fstab_filter_options(opts, filter, NULL, &timeout, NULL);
         if (r < 0)
                 return log_warning_errno(r, "Failed to parse options: %m");
         if (r == 0)
@@ -159,11 +160,21 @@ static int write_idle_timeout(FILE *f, const char *where, const char *opts) {
                 return 0;
         }
 
-        fprintf(f, "TimeoutIdleSec=%s\n", format_timespan(timespan, sizeof(timespan), u, 0));
+        fprintf(f, "%s=%s\n", variable, format_timespan(timespan, sizeof(timespan), u, 0));
 
         return 0;
 }
 
+static int write_idle_timeout(FILE *f, const char *where, const char *opts) {
+        return write_timeout(f, where, opts,
+                             "x-systemd.idle-timeout\0", "TimeoutIdleSec");
+}
+
+static int write_mount_timeout(FILE *f, const char *where, const char *opts) {
+        return write_timeout(f, where, opts,
+                             "x-systemd.mount-timeout\0", "TimeoutSec");
+}
+
 static int write_requires_after(FILE *f, const char *opts) {
         _cleanup_strv_free_ char **names = NULL, **units = NULL;
         _cleanup_free_ char *res = NULL;
@@ -327,6 +338,10 @@ static int add_mount(
         if (r < 0)
                 return r;
 
+        r = write_mount_timeout(f, where, opts);
+        if (r < 0)
+                return r;
+
         if (!isempty(filtered) && !streq(filtered, "defaults"))
                 fprintf(f, "Options=%s\n", filtered);