From 86b23b07c96b185126bfbf217227dad362a20c25 Mon Sep 17 00:00:00 2001

From: Jan Synacek <jsynacek@redhat.com>

Date: Wed, 24 Sep 2014 14:29:05 +0200

Subject: [PATCH] swap: introduce Discard property

Process possible "discard" values from /etc/fstab.

---

 man/systemd.swap.xml                  | 14 ++++++++++

 src/core/execute.c                    | 25 ++++++++++++++++++

 src/core/execute.h                    |  1 +

 src/core/load-fragment-gperf.gperf.m4 |  1 +

 src/core/swap.c                       | 49 +++++++++++++++++++++++------------

 src/core/swap.h                       |  1 +

 src/fstab-generator/fstab-generator.c | 10 +++++++

 7 files changed, 84 insertions(+), 17 deletions(-)

diff --git a/man/systemd.swap.xml b/man/systemd.swap.xml

index 62a4d08b9c..481dc52454 100644

--- a/man/systemd.swap.xml

+++ b/man/systemd.swap.xml

@@ -171,6 +171,20 @@

                         </varlistentry>

                         <varlistentry>

+                                <term><varname>Discard=</varname></term>

+

+                                <listitem><para>Enable discards, if the swap

+                                backing device supports the discard or trim

+                                operation. Can be one of <literal>none</literal>,

+                                <literal>once</literal>, <literal>pages</literal>

+                                or <literal>all</literal>.  Defaults to

+                                <literal>none</literal>. (See

+                                <citerefentry><refentrytitle>swapon</refentrytitle><manvolnum>8</manvolnum></citerefentry>

+                                for more information.)

+                                </para></listitem>

+                        </varlistentry>

+

+                        <varlistentry>

                                 <term><varname>TimeoutSec=</varname></term>

                                 <listitem><para>Configures the time to

                                 wait for the swapon command to

diff --git a/src/core/execute.c b/src/core/execute.c

index 8c9dfde00a..07ec7a28d6 100644

--- a/src/core/execute.c

+++ b/src/core/execute.c

@@ -2566,6 +2566,31 @@ int exec_command_set(ExecCommand *c, const char *path, ...) {

         return 0;

 }

+int exec_command_append(ExecCommand *c, const char *path, ...) {

+        va_list ap;

+        char **l;

+        int r;

+

+        assert(c);

+        assert(path);

+

+        va_start(ap, path);

+        l = strv_new_ap(path, ap);

+        va_end(ap);

+

+        if (!l)

+                return -ENOMEM;

+

+        r = strv_extend_strv(&c->argv, l);

+        if (r < 0) {

+                strv_free(l);

+                return r;

+        }

+

+        return 0;

+}

+

+

 static int exec_runtime_allocate(ExecRuntime **rt) {

         if (*rt)

diff --git a/src/core/execute.h b/src/core/execute.h

index 6f35736eda..2694315155 100644

--- a/src/core/execute.h

+++ b/src/core/execute.h

@@ -233,6 +233,7 @@ void exec_command_dump(ExecCommand *c, FILE *f, const char *prefix);

 void exec_command_dump_list(ExecCommand *c, FILE *f, const char *prefix);

 void exec_command_append_list(ExecCommand **l, ExecCommand *e);

 int exec_command_set(ExecCommand *c, const char *path, ...);

+int exec_command_append(ExecCommand *c, const char *path, ...);

 void exec_context_init(ExecContext *c);

 void exec_context_done(ExecContext *c);

diff --git a/src/core/load-fragment-gperf.gperf.m4 b/src/core/load-fragment-gperf.gperf.m4

index 050c5d819f..8805411f28 100644

--- a/src/core/load-fragment-gperf.gperf.m4

+++ b/src/core/load-fragment-gperf.gperf.m4

@@ -297,6 +297,7 @@ Automount.DirectoryMode,         config_parse_mode,                  0,

 m4_dnl

 Swap.What,                       config_parse_path,                  0,                             offsetof(Swap, parameters_fragment.what)

 Swap.Priority,                   config_parse_int,                   0,                             offsetof(Swap, parameters_fragment.priority)

+Swap.Discard,                    config_parse_string,                0,                             offsetof(Swap, parameters_fragment.discard)

 Swap.TimeoutSec,                 config_parse_sec,                   0,                             offsetof(Swap, timeout_usec)

 EXEC_CONTEXT_CONFIG_ITEMS(Swap)m4_dnl

 CGROUP_CONTEXT_CONFIG_ITEMS(Swap)m4_dnl

diff --git a/src/core/swap.c b/src/core/swap.c

index b88a914f72..2e12824049 100644

--- a/src/core/swap.c

+++ b/src/core/swap.c

@@ -152,6 +152,9 @@ static void swap_done(Unit *u) {

         free(s->parameters_fragment.what);

         s->parameters_fragment.what = NULL;

+        free(s->parameters_fragment.discard);

+        s->parameters_fragment.discard = NULL;

+

         s->exec_runtime = exec_runtime_unref(s->exec_runtime);

         exec_command_done_array(s->exec_command, _SWAP_EXEC_COMMAND_MAX);

         s->control_command = NULL;

@@ -602,10 +605,12 @@ static void swap_dump(Unit *u, FILE *f, const char *prefix) {

                 fprintf(f,

                         "%sPriority: %i\n"

                         "%sNoAuto: %s\n"

-                        "%sNoFail: %s\n",

+                        "%sNoFail: %s\n"

+                        "%sDiscard: %s\n",

                         prefix, p->priority,

                         prefix, yes_no(p->noauto),

-                        prefix, yes_no(p->nofail));

+                        prefix, yes_no(p->nofail),

+                        prefix, p->discard);

         if (s->control_pid > 0)

                 fprintf(f,

@@ -734,36 +739,46 @@ fail:

 static void swap_enter_activating(Swap *s) {

         int r, priority;

+        char *discard;

         assert(s);

         s->control_command_id = SWAP_EXEC_ACTIVATE;

         s->control_command = s->exec_command + SWAP_EXEC_ACTIVATE;

-        if (s->from_fragment)

+        if (s->from_fragment) {

                 priority = s->parameters_fragment.priority;

-        else

+                discard = s->parameters_fragment.discard;

+        } else {

                 priority = -1;

+                discard = NULL;

+        }

+

+        r = exec_command_set(s->control_command, "/sbin/swapon", NULL);

+        if (r < 0)

+                goto fail;

         if (priority >= 0) {

                 char p[DECIMAL_STR_MAX(int)];

                 sprintf(p, "%i", priority);

+                r = exec_command_append(s->control_command, "-p", p, NULL);

+                if (r < 0)

+                        goto fail;

+        }

-                r = exec_command_set(

-                                s->control_command,

-                                "/sbin/swapon",

-                                "-p",

-                                p,

-                                s->what,

-                                NULL);

-        } else

-                r = exec_command_set(

-                                s->control_command,

-                                "/sbin/swapon",

-                                s->what,

-                                NULL);

+        if (discard && !streq(discard, "none")) {

+                const char *discard_arg = "--discard";

+

+                if (!streq(discard, "all"))

+                        discard_arg = strappenda("--discard=", discard);

+

+                r = exec_command_append(s->control_command, discard_arg, NULL);

+                if (r < 0)

+                        goto fail;

+        }

+        r = exec_command_append(s->control_command, s->what, NULL);

         if (r < 0)

                 goto fail;

diff --git a/src/core/swap.h b/src/core/swap.h

index f2ae49b1de..3482d651ec 100644

--- a/src/core/swap.h

+++ b/src/core/swap.h

@@ -63,6 +63,7 @@ typedef enum SwapResult {

 typedef struct SwapParameters {

         char *what;

+        char *discard;

         int priority;

         bool noauto:1;

         bool nofail:1;

diff --git a/src/fstab-generator/fstab-generator.c b/src/fstab-generator/fstab-generator.c

index 2c38ab977c..5569325a16 100644

--- a/src/fstab-generator/fstab-generator.c

+++ b/src/fstab-generator/fstab-generator.c

@@ -73,6 +73,8 @@ static int mount_find_pri(struct mntent *me, int *ret) {

 static int add_swap(const char *what, struct mntent *me) {

         _cleanup_free_ char *name = NULL, *unit = NULL, *lnk = NULL;

         _cleanup_fclose_ FILE *f = NULL;

+        char *discard = NULL;

+

         bool noauto;

         int r, pri = -1;

@@ -118,6 +120,14 @@ static int add_swap(const char *what, struct mntent *me) {

                 "What=%s\n",

                 what);

+        discard = mount_test_option(me->mnt_opts, "discard");

+        if (discard) {

+                discard = strpbrk(discard, "=");

+                fprintf(f,

+                        "Discard=%s\n",

+                        discard ? discard+1 : "all");

+        }

+

         if (pri >= 0)

                 fprintf(f,

                         "Priority=%i\n",