Accepting request 142164 from home:fcrozat:branches:Base:System

- Add remount-ro-before-unmount.patch: always remount read-only
  before unmounting in final shutdown loop.
- Add switch-root-try-pivot-root.patch: try pivot_root before
  overmounting /

OBS-URL: https://build.opensuse.org/request/show/142164
OBS-URL: https://build.opensuse.org/package/show/Base:System/systemd?expand=0&rev=313

remount-ro-before-unmount.patch

@@ -0,0 +1,95 @@
+From 93bd157722c76b47d80742f290373c1ce2865070 Mon Sep 17 00:00:00 2001
+From: Lennart Poettering <lennart@poettering.net>
+Date: Fri, 16 Nov 2012 18:36:28 +0100
+Subject: [PATCH] umount: always remount read-only before unmounting in final
+ shutdown loop
+
+---
+ src/core/umount.c |   57 +++++++++++++++++++++++++----------------------------
+ 1 file changed, 27 insertions(+), 30 deletions(-)
+
+diff --git a/src/core/umount.c b/src/core/umount.c
+index 83c9de3..e794057 100644
+--- a/src/core/umount.c
++++ b/src/core/umount.c
+@@ -407,6 +407,33 @@ static int mount_points_list_umount(MountPoint **head, bool *changed, bool log_e
+         assert(head);
+ 
+         LIST_FOREACH_SAFE(mount_point, m, n, *head) {
++
++                /* If we are in a container, don't attempt to
++                   read-only mount anything as that brings no real
++                   benefits, but might confuse the host, as we remount
++                   the superblock here, not the bind mound. */
++                if (detect_container(NULL) <= 0)  {
++                        /* We always try to remount directories
++                         * read-only first, before we go on and umount
++                         * them.
++                         *
++                         * Mount points can be stacked. If a mount
++                         * point is stacked below / or /usr, we
++                         * cannnot umount or remount it directly,
++                         * since there is no way to refer to the
++                         * underlying mount. There's nothing we can do
++                         * about it for the general case, but we can
++                         * do something about it if it is aliased
++                         * somehwere else via a bind mount. If we
++                         * explicitly remount the super block of that
++                         * alias read-only we hence should be
++                         * relatively safe regarding keeping the fs we
++                         * can otherwise not see dirty. */
++                        mount(NULL, m->path, NULL, MS_REMOUNT|MS_RDONLY, NULL);
++                }
++
++                /* Skip / and /usr since we cannot unmount that
++                 * anyway, since we are running from it */
+                 if (path_equal(m->path, "/")
+ #ifndef HAVE_SPLIT_USR
+                     || path_equal(m->path, "/usr")
+@@ -432,29 +459,6 @@ static int mount_points_list_umount(MountPoint **head, bool *changed, bool log_e
+         return n_failed;
+ }
+ 
+-static int mount_points_list_remount_read_only(MountPoint **head, bool *changed) {
+-        MountPoint *m, *n;
+-        int n_failed = 0;
+-
+-        assert(head);
+-
+-        LIST_FOREACH_SAFE(mount_point, m, n, *head) {
+-
+-                /* Trying to remount read-only */
+-                if (mount(NULL, m->path, NULL, MS_REMOUNT|MS_RDONLY, NULL) == 0) {
+-                        if (changed)
+-                                *changed = true;
+-
+-                        mount_point_free(head, m);
+-                } else {
+-                        log_warning("Could not remount as read-only %s: %m", m->path);
+-                        n_failed++;
+-                }
+-        }
+-
+-        return n_failed;
+-}
+-
+ static int swap_points_list_off(MountPoint **head, bool *changed) {
+         MountPoint *m, *n;
+         int n_failed = 0;
+@@ -571,13 +575,6 @@ int umount_all(bool *changed) {
+         if (r <= 0)
+                 goto end;
+ 
+-        /* If we are in a container, don't attempt to read-only mount
+-           anything as that brings no real benefits, but might confuse
+-           the host, as we remount the superblock here, not the bind
+-           mound. */
+-        if (detect_container(NULL) <= 0)
+-                r = mount_points_list_remount_read_only(&mp_list_head, changed);
+-
+   end:
+         mount_points_list_free(&mp_list_head);
+ 
+-- 
+1.7.10.4
+

switch-root-try-pivot-root.patch

@@ -0,0 +1,81 @@
+From 891a4918ef75fa81e22691156c050d061bd53dd3 Mon Sep 17 00:00:00 2001
+From: Lennart Poettering <lennart@poettering.net>
+Date: Fri, 16 Nov 2012 18:15:30 +0100
+Subject: [PATCH] switch-root: try pivot_root() before overmounting /
+
+We should always try to umount the old root dir if possible, instead of
+overmounting it -- if that's possible.
+
+The initial ("first") kernel rootfs can never be umounted, hence
+for the usual nitrd case we never bothered using pivot_root() and
+hence with fully unmounting it. However, fedup now tranisitions twice
+during boot, and in that case it is highly desirable that the "second"
+root dir is entirely unmounted when we switch to the "third". This patch
+makes that possible.
+
+The pivot_root() needs a directory in the "third" root dir, to move the
+"second" root dir to. We use /mnt for that, under the assumption that
+this directory is likely to exist, and is not itself a mount point.
+---
+ src/core/switch-root.c |   27 ++++++++++++++++++++++++++-
+ 1 file changed, 26 insertions(+), 1 deletion(-)
+
+diff --git a/src/core/switch-root.c b/src/core/switch-root.c
+index 150332a..ce0e41d 100644
+--- a/src/core/switch-root.c
++++ b/src/core/switch-root.c
+@@ -30,6 +30,7 @@
+ #include "util.h"
+ #include "path-util.h"
+ #include "switch-root.h"
++#include "missing.h"
+ 
+ int switch_root(const char *new_root) {
+ 
+@@ -44,10 +45,21 @@ int switch_root(const char *new_root) {
+         struct stat new_root_stat;
+         bool old_root_remove;
+         const char *i;
++        _cleanup_free_ char *temporary_old_root = NULL;
+ 
+         if (path_equal(new_root, "/"))
+                 return 0;
+ 
++        /* When using pivot_root() we assume that /mnt exists as place
++         * we can temporarily move the old root to. As we immediately
++         * unmount it from there it doesn't matter much which
++         * directory we choose for this, but it should be more likely
++         * than not that /mnt exists and is suitable as mount point
++         * and is on the same fs as the old root dir */
++        temporary_old_root = strappend(new_root, "/mnt");
++        if (!temporary_old_root)
++                return -ENOMEM;
++
+         old_root_remove = in_initrd();
+ 
+         if (stat(new_root, &new_root_stat) < 0) {
+@@ -103,7 +115,20 @@ int switch_root(const char *new_root) {
+                         log_warning("Failed to open root directory: %m");
+         }
+ 
+-        if (mount(new_root, "/", NULL, MS_MOVE, NULL) < 0) {
++        /* We first try a pivot_root() so that we can umount the old
++         * root dir. In many cases (i.e. where rootfs is /), that's
++         * not possible however, and hence we simply overmount root */
++        if (pivot_root(new_root, temporary_old_root) >= 0) {
++
++                /* Immediately get rid of the old root. Since we are
++                 * running off it we need to do this lazily. */
++                if (umount2(temporary_old_root, MNT_DETACH) < 0) {
++                        r = -errno;
++                        log_error("Failed to umount old root dir %s: %m", temporary_old_root);
++                        goto fail;
++                }
++
++        } else if (mount(new_root, "/", NULL, MS_MOVE, NULL) < 0) {
+                 r = -errno;
+                 log_error("Failed to mount moving %s to /: %m", new_root);
+                 goto fail;
+-- 
+1.7.10.4
+

systemd-mini.changes

@@ -1,3 +1,11 @@
+-------------------------------------------------------------------
+Tue Nov 20 18:25:49 CET 2012 - fcrozat@suse.com
+
+- Add remount-ro-before-unmount.patch: always remount read-only
+  before unmounting in final shutdown loop.
+- Add switch-root-try-pivot-root.patch: try pivot_root before
+  overmounting /
+
 -------------------------------------------------------------------
 Tue Nov 20 09:36:43 UTC 2012 - fcrozat@suse.com
 

systemd-mini.spec

@@ -148,6 +148,10 @@ Patch66:        fix-dbus-crash.patch
 Patch67:        sync-on-shutdown.patch
 # PATCH-FIX-UPSTREAM mount-efivars.patch fcrozat@suse.com -- mount efivars if booting under UEFI
 Patch68:        mount-efivars.patch
+# PATCH-FIX-UPSTREAM switch-root-try-pivot-root.patch fcrozat@suse.com -- try pivot_root before overmounting /
+Patch69:        switch-root-try-pivot-root.patch
+# PATCH-FIX-UPSTREAM remount-ro-before-unmount.patch fcrozat@suse.com -- remount ro before unmounting in final shutdown loop
+Patch70:        remount-ro-before-unmount.patch
 
 # udev patches
 # PATCH-FIX-OPENSUSE 0001-Reinstate-TIMEOUT-handling.patch
@@ -353,6 +357,8 @@ cp %{SOURCE7} m4/
 %patch66 -p1
 %patch67 -p1
 %patch68 -p1
+%patch69 -p1
+%patch70 -p1
 
 %build
 autoreconf -fiv

systemd.changes

@@ -1,3 +1,11 @@
+-------------------------------------------------------------------
+Tue Nov 20 18:25:49 CET 2012 - fcrozat@suse.com
+
+- Add remount-ro-before-unmount.patch: always remount read-only
+  before unmounting in final shutdown loop.
+- Add switch-root-try-pivot-root.patch: try pivot_root before
+  overmounting /
+
 -------------------------------------------------------------------
 Tue Nov 20 09:36:43 UTC 2012 - fcrozat@suse.com
 

systemd.spec

@@ -143,6 +143,10 @@ Patch66:        fix-dbus-crash.patch
 Patch67:        sync-on-shutdown.patch
 # PATCH-FIX-UPSTREAM mount-efivars.patch fcrozat@suse.com -- mount efivars if booting under UEFI
 Patch68:        mount-efivars.patch
+# PATCH-FIX-UPSTREAM switch-root-try-pivot-root.patch fcrozat@suse.com -- try pivot_root before overmounting /
+Patch69:        switch-root-try-pivot-root.patch
+# PATCH-FIX-UPSTREAM remount-ro-before-unmount.patch fcrozat@suse.com -- remount ro before unmounting in final shutdown loop
+Patch70:        remount-ro-before-unmount.patch
 
 # udev patches
 # PATCH-FIX-OPENSUSE 0001-Reinstate-TIMEOUT-handling.patch
@@ -348,6 +352,8 @@ cp %{SOURCE7} m4/
 %patch66 -p1
 %patch67 -p1
 %patch68 -p1
+%patch69 -p1
+%patch70 -p1
 
 %build
 autoreconf -fiv