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umount: always remount read-only before unmounting in final shutdown loop

This commit is contained in:
Lennart Poettering 2012-11-16 18:36:28 +01:00
parent 891a4918ef
commit 93bd157722
1 changed files with 27 additions and 30 deletions
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57
src/core/umount.c
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@ -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);