1 files changed, 41 insertions, 38 deletions

diff --git a/src/core/umount.c b/src/core/umount.c
index a5a215b2b5..96232d38db 100644
--- a/src/core/umount.c
+++ b/src/core/umount.c
@@ -34,6 +34,7 @@
 #include "umount.h"
 #include "path-util.h"
 #include "util.h"
+#include "virt.h"
 
 typedef struct MountPoint {
         char *path;
@@ -406,18 +407,44 @@ 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. They have
+                 * already been remounted ro. */
                 if (path_equal(m->path, "/")
 #ifndef HAVE_SPLIT_USR
                     || path_equal(m->path, "/usr")
 #endif
-                ) {
-                        n_failed++;
+                )
                         continue;
-                }
 
                 /* Trying to umount. Forcing to umount if busy (only for NFS mounts) */
+                log_info("Unmounting %s.", m->path);
                 if (umount2(m->path, MNT_FORCE) == 0) {
-                        log_info("Unmounted %s.", m->path);
                         if (changed)
                                 *changed = true;
 
@@ -431,29 +458,6 @@ 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_MGC_VAL|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;
@@ -461,6 +465,7 @@ static int swap_points_list_off(MountPoint **head, bool *changed) {
         assert(head);
 
         LIST_FOREACH_SAFE(mount_point, m, n, *head) {
+                log_info("Deactivating swap %s.", m->path);
                 if (swapoff(m->path) == 0) {
                         if (changed)
                                 *changed = true;
@@ -496,14 +501,15 @@ static int loopback_points_list_detach(MountPoint **head, bool *changed) {
                         continue;
                 }
 
-                if ((r = delete_loopback(m->path)) >= 0) {
-
+                log_info("Detaching loopback %s.", m->path);
+                r = delete_loopback(m->path);
+                if (r >= 0) {
                         if (r > 0 && changed)
                                 *changed = true;
 
                         mount_point_free(head, m);
                 } else {
-                        log_warning("Could not delete loopback %s: %m", m->path);
+                        log_warning("Could not detach loopback %s: %m", m->path);
                         n_failed++;
                 }
         }
@@ -530,14 +536,15 @@ static int dm_points_list_detach(MountPoint **head, bool *changed) {
                         continue;
                 }
 
-                if ((r = delete_dm(m->devnum)) >= 0) {
-
-                        if (r > 0 && changed)
+                log_info("Detaching DM %u:%u.", major(m->devnum), minor(m->devnum));
+                r = delete_dm(m->devnum);
+                if (r >= 0) {
+                        if (changed)
                                 *changed = true;
 
                         mount_point_free(head, m);
                 } else {
-                        log_warning("Could not delete dm %s: %m", m->path);
+                        log_warning("Could not detach DM %s: %m", m->path);
                         n_failed++;
                 }
         }
@@ -548,11 +555,9 @@ static int dm_points_list_detach(MountPoint **head, bool *changed) {
 int umount_all(bool *changed) {
         int r;
         bool umount_changed;
-
         LIST_HEAD(MountPoint, mp_list_head);
 
         LIST_HEAD_INIT(MountPoint, mp_list_head);
-
         r = mount_points_list_get(&mp_list_head);
         if (r < 0)
                 goto end;
@@ -572,8 +577,6 @@ int umount_all(bool *changed) {
         if (r <= 0)
                 goto end;
 
-        r = mount_points_list_remount_read_only(&mp_list_head, changed);
-
   end:
         mount_points_list_free(&mp_list_head);