src/core/umount.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2010 ProFUSION embedded systems
   6 ***/
   7
   8 #include <errno.h>
   9 #include <fcntl.h>
  10 #include <linux/loop.h>
  11 #include <string.h>
  12 #include <sys/mount.h>
  13 #include <sys/swap.h>
  14
  15 /* This needs to be after sys/mount.h :( */
  16 #include <libmount.h>
  17
  18 #include "libudev.h"
  19
  20 #include "alloc-util.h"
  21 #include "blockdev-util.h"
  22 #include "def.h"
  23 #include "escape.h"
  24 #include "fd-util.h"
  25 #include "fstab-util.h"
  26 #include "linux-3.13/dm-ioctl.h"
  27 #include "mount-setup.h"
  28 #include "mount-util.h"
  29 #include "path-util.h"
  30 #include "process-util.h"
  31 #include "signal-util.h"
  32 #include "string-util.h"
  33 #include "udev-util.h"
  34 #include "umount.h"
  35 #include "util.h"
  36 #include "virt.h"
  37
  38 DEFINE_TRIVIAL_CLEANUP_FUNC(struct libmnt_table*, mnt_free_table);
  39 DEFINE_TRIVIAL_CLEANUP_FUNC(struct libmnt_iter*, mnt_free_iter);
  40
  41 static void mount_point_free(MountPoint **head, MountPoint *m) {
  42         assert(head);
  43         assert(m);
  44
  45         LIST_REMOVE(mount_point, *head, m);
  46
  47         free(m->path);
  48         free(m->remount_options);
  49         free(m);
  50 }
  51
  52 void mount_points_list_free(MountPoint **head) {
  53         assert(head);
  54
  55         while (*head)
  56                 mount_point_free(head, *head);
  57 }
  58
  59 int mount_points_list_get(const char *mountinfo, MountPoint **head) {
  60         _cleanup_(mnt_free_tablep) struct libmnt_table *t = NULL;
  61         _cleanup_(mnt_free_iterp) struct libmnt_iter *i = NULL;
  62         int r;
  63
  64         assert(head);
  65
  66         t = mnt_new_table();
  67         i = mnt_new_iter(MNT_ITER_FORWARD);
  68         if (!t || !i)
  69                 return log_oom();
  70
  71         r = mnt_table_parse_mtab(t, mountinfo);
  72         if (r < 0)
  73                 return log_error_errno(r, "Failed to parse %s: %m", mountinfo);
  74
  75         for (;;) {
  76                 struct libmnt_fs *fs;
  77                 const char *path, *options, *fstype;
  78                 _cleanup_free_ char *p = NULL;
  79                 unsigned long remount_flags = 0u;
  80                 _cleanup_free_ char *remount_options = NULL;
  81                 bool try_remount_ro;
  82                 MountPoint *m;
  83
  84                 r = mnt_table_next_fs(t, i, &fs);
  85                 if (r == 1)
  86                         break;
  87                 if (r < 0)
  88                         return log_error_errno(r, "Failed to get next entry from %s: %m", mountinfo);
  89
  90                 path = mnt_fs_get_target(fs);
  91                 if (!path)
  92                         continue;
  93
  94                 if (cunescape(path, UNESCAPE_RELAX, &p) < 0)
  95                         return log_oom();
  96
  97                 options = mnt_fs_get_options(fs);
  98                 fstype = mnt_fs_get_fstype(fs);
  99
 100                 /* Ignore mount points we can't unmount because they
 101                  * are API or because we are keeping them open (like
 102                  * /dev/console). Also, ignore all mounts below API
 103                  * file systems, since they are likely virtual too,
 104                  * and hence not worth spending time on. Also, in
 105                  * unprivileged containers we might lack the rights to
 106                  * unmount these things, hence don't bother. */
 107                 if (mount_point_is_api(p) ||
 108                     mount_point_ignore(p) ||
 109                     path_startswith(p, "/dev") ||
 110                     path_startswith(p, "/sys") ||
 111                     path_startswith(p, "/proc"))
 112                         continue;
 113
 114
 115                 /* If we are in a container, don't attempt to
 116                  * read-only mount anything as that brings no real
 117                  * benefits, but might confuse the host, as we remount
 118                  * the superblock here, not the bind mount.
 119                  *
 120                  * If the filesystem is a network fs, also skip the
 121                  * remount. It brings no value (we cannot leave
 122                  * a "dirty fs") and could hang if the network is down.
 123                  * Note that umount2() is more careful and will not
 124                  * hang because of the network being down. */
 125                 try_remount_ro = detect_container() <= 0 &&
 126                                  !fstype_is_network(fstype) &&
 127                                  !fstype_is_api_vfs(fstype) &&
 128                                  !fstype_is_ro(fstype) &&
 129                                  !fstab_test_yes_no_option(options, "ro\0rw\0");
 130
 131                 if (try_remount_ro) {
 132                         /* mount(2) states that mount flags and options need to be exactly the same
 133                          * as they were when the filesystem was mounted, except for the desired
 134                          * changes. So we reconstruct both here and adjust them for the later
 135                          * remount call too. */
 136
 137                         r = mnt_fs_get_propagation(fs, &remount_flags);
 138                         if (r < 0) {
 139                                 log_warning_errno(r, "mnt_fs_get_propagation() failed for %s, ignoring: %m", path);
 140                                 continue;
 141                         }
 142
 143                         r = mount_option_mangle(options, remount_flags, &remount_flags, &remount_options);
 144                         if (r < 0) {
 145                                 log_warning_errno(r, "mount_option_mangle failed for %s, ignoring: %m", path);
 146                                 continue;
 147                         }
 148
 149                         /* MS_BIND is special. If it is provided it will only make the mount-point
 150                          * read-only. If left out, the super block itself is remounted, which we want. */
 151                         remount_flags = (remount_flags|MS_REMOUNT|MS_RDONLY) & ~MS_BIND;
 152                 }
 153
 154                 m = new0(MountPoint, 1);
 155                 if (!m)
 156                         return log_oom();
 157
 158                 free_and_replace(m->path, p);
 159                 free_and_replace(m->remount_options, remount_options);
 160                 m->remount_flags = remount_flags;
 161                 m->try_remount_ro = try_remount_ro;
 162
 163                 LIST_PREPEND(mount_point, *head, m);
 164         }
 165
 166         return 0;
 167 }
 168
 169 int swap_list_get(const char *swaps, MountPoint **head) {
 170         _cleanup_(mnt_free_tablep) struct libmnt_table *t = NULL;
 171         _cleanup_(mnt_free_iterp) struct libmnt_iter *i = NULL;
 172         int r;
 173
 174         assert(head);
 175
 176         t = mnt_new_table();
 177         i = mnt_new_iter(MNT_ITER_FORWARD);
 178         if (!t || !i)
 179                 return log_oom();
 180
 181         r = mnt_table_parse_swaps(t, swaps);
 182         if (r < 0)
 183                 return log_error_errno(r, "Failed to parse %s: %m", swaps);
 184
 185         for (;;) {
 186                 struct libmnt_fs *fs;
 187
 188                 MountPoint *swap;
 189                 const char *source;
 190                 _cleanup_free_ char *d = NULL;
 191
 192                 r = mnt_table_next_fs(t, i, &fs);
 193                 if (r == 1)
 194                         break;
 195                 if (r < 0)
 196                         return log_error_errno(r, "Failed to get next entry from %s: %m", swaps);
 197
 198                 source = mnt_fs_get_source(fs);
 199                 if (!source)
 200                         continue;
 201
 202                 r = cunescape(source, UNESCAPE_RELAX, &d);
 203                 if (r < 0)
 204                         return r;
 205
 206                 swap = new0(MountPoint, 1);
 207                 if (!swap)
 208                         return -ENOMEM;
 209
 210                 free_and_replace(swap->path, d);
 211                 LIST_PREPEND(mount_point, *head, swap);
 212         }
 213
 214         return 0;
 215 }
 216
 217 static int loopback_list_get(MountPoint **head) {
 218         _cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL;
 219         struct udev_list_entry *item = NULL, *first = NULL;
 220         _cleanup_udev_unref_ struct udev *udev = NULL;
 221         int r;
 222
 223         assert(head);
 224
 225         udev = udev_new();
 226         if (!udev)
 227                 return -ENOMEM;
 228
 229         e = udev_enumerate_new(udev);
 230         if (!e)
 231                 return -ENOMEM;
 232
 233         r = udev_enumerate_add_match_subsystem(e, "block");
 234         if (r < 0)
 235                 return r;
 236
 237         r = udev_enumerate_add_match_sysname(e, "loop*");
 238         if (r < 0)
 239                 return r;
 240
 241         r = udev_enumerate_add_match_sysattr(e, "loop/backing_file", NULL);
 242         if (r < 0)
 243                 return r;
 244
 245         r = udev_enumerate_scan_devices(e);
 246         if (r < 0)
 247                 return r;
 248
 249         first = udev_enumerate_get_list_entry(e);
 250         udev_list_entry_foreach(item, first) {
 251                 _cleanup_udev_device_unref_ struct udev_device *d;
 252                 const char *dn;
 253                 _cleanup_free_ MountPoint *lb = NULL;
 254
 255                 d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item));
 256                 if (!d)
 257                         return -ENOMEM;
 258
 259                 dn = udev_device_get_devnode(d);
 260                 if (!dn)
 261                         continue;
 262
 263                 lb = new0(MountPoint, 1);
 264                 if (!lb)
 265                         return -ENOMEM;
 266
 267                 r = free_and_strdup(&lb->path, dn);
 268                 if (r < 0)
 269                         return r;
 270
 271                 LIST_PREPEND(mount_point, *head, lb);
 272                 lb = NULL;
 273         }
 274
 275         return 0;
 276 }
 277
 278 static int dm_list_get(MountPoint **head) {
 279         _cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL;
 280         struct udev_list_entry *item = NULL, *first = NULL;
 281         _cleanup_udev_unref_ struct udev *udev = NULL;
 282         int r;
 283
 284         assert(head);
 285
 286         udev = udev_new();
 287         if (!udev)
 288                 return -ENOMEM;
 289
 290         e = udev_enumerate_new(udev);
 291         if (!e)
 292                 return -ENOMEM;
 293
 294         r = udev_enumerate_add_match_subsystem(e, "block");
 295         if (r < 0)
 296                 return r;
 297
 298         r = udev_enumerate_add_match_sysname(e, "dm-*");
 299         if (r < 0)
 300                 return r;
 301
 302         r = udev_enumerate_scan_devices(e);
 303         if (r < 0)
 304                 return r;
 305
 306         first = udev_enumerate_get_list_entry(e);
 307         udev_list_entry_foreach(item, first) {
 308                 _cleanup_udev_device_unref_ struct udev_device *d;
 309                 dev_t devnum;
 310                 const char *dn;
 311                 _cleanup_free_ MountPoint *m = NULL;
 312
 313                 d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item));
 314                 if (!d)
 315                         return -ENOMEM;
 316
 317                 devnum = udev_device_get_devnum(d);
 318                 dn = udev_device_get_devnode(d);
 319                 if (major(devnum) == 0 || !dn)
 320                         continue;
 321
 322                 m = new0(MountPoint, 1);
 323                 if (!m)
 324                         return -ENOMEM;
 325
 326                 m->devnum = devnum;
 327                 r = free_and_strdup(&m->path, dn);
 328                 if (r < 0)
 329                         return r;
 330
 331                 LIST_PREPEND(mount_point, *head, m);
 332                 m = NULL;
 333         }
 334
 335         return 0;
 336 }
 337
 338 static int delete_loopback(const char *device) {
 339         _cleanup_close_ int fd = -1;
 340         int r;
 341
 342         assert(device);
 343
 344         fd = open(device, O_RDONLY|O_CLOEXEC);
 345         if (fd < 0)
 346                 return errno == ENOENT ? 0 : -errno;
 347
 348         r = ioctl(fd, LOOP_CLR_FD, 0);
 349         if (r >= 0)
 350                 return 1;
 351
 352         /* ENXIO: not bound, so no error */
 353         if (errno == ENXIO)
 354                 return 0;
 355
 356         return -errno;
 357 }
 358
 359 static int delete_dm(dev_t devnum) {
 360
 361         struct dm_ioctl dm = {
 362                 .version = {
 363                         DM_VERSION_MAJOR,
 364                         DM_VERSION_MINOR,
 365                         DM_VERSION_PATCHLEVEL
 366                 },
 367                 .data_size = sizeof(dm),
 368                 .dev = devnum,
 369         };
 370
 371         _cleanup_close_ int fd = -1;
 372
 373         assert(major(devnum) != 0);
 374
 375         fd = open("/dev/mapper/control", O_RDWR|O_CLOEXEC);
 376         if (fd < 0)
 377                 return -errno;
 378
 379         if (ioctl(fd, DM_DEV_REMOVE, &dm) < 0)
 380                 return -errno;
 381
 382         return 0;
 383 }
 384
 385 static bool nonunmountable_path(const char *path) {
 386         return path_equal(path, "/")
 387 #if ! HAVE_SPLIT_USR
 388                 || path_equal(path, "/usr")
 389 #endif
 390                 || path_startswith(path, "/run/initramfs");
 391 }
 392
 393 static int remount_with_timeout(MountPoint *m, int umount_log_level) {
 394         pid_t pid;
 395         int r;
 396
 397         BLOCK_SIGNALS(SIGCHLD);
 398
 399         assert(m);
 400
 401         /* Due to the possiblity of a remount operation hanging, we
 402          * fork a child process and set a timeout. If the timeout
 403          * lapses, the assumption is that that particular remount
 404          * failed. */
 405         r = safe_fork("(sd-remount)", FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_LOG|FORK_REOPEN_LOG, &pid);
 406         if (r < 0)
 407                 return r;
 408         if (r == 0) {
 409                 log_info("Remounting '%s' read-only in with options '%s'.", m->path, m->remount_options);
 410
 411                 /* Start the mount operation here in the child */
 412                 r = mount(NULL, m->path, NULL, m->remount_flags, m->remount_options);
 413                 if (r < 0)
 414                         log_full_errno(umount_log_level, errno, "Failed to remount '%s' read-only: %m", m->path);
 415
 416                 _exit(r < 0 ? EXIT_FAILURE : EXIT_SUCCESS);
 417         }
 418
 419         r = wait_for_terminate_with_timeout(pid, DEFAULT_TIMEOUT_USEC);
 420         if (r == -ETIMEDOUT) {
 421                 log_error_errno(r, "Remounting '%s' timed out, issuing SIGKILL to PID " PID_FMT ".", m->path, pid);
 422                 (void) kill(pid, SIGKILL);
 423         } else if (r == -EPROTO)
 424                 log_debug_errno(r, "Remounting '%s' failed abnormally, child process " PID_FMT " aborted or exited non-zero.", m->path, pid);
 425         else if (r < 0)
 426                 log_error_errno(r, "Remounting '%s' failed unexpectedly, couldn't wait for child process " PID_FMT ": %m", m->path, pid);
 427
 428         return r;
 429 }
 430
 431 static int umount_with_timeout(MountPoint *m, int umount_log_level) {
 432         pid_t pid;
 433         int r;
 434
 435         BLOCK_SIGNALS(SIGCHLD);
 436
 437         assert(m);
 438
 439         /* Due to the possiblity of a umount operation hanging, we
 440          * fork a child process and set a timeout. If the timeout
 441          * lapses, the assumption is that that particular umount
 442          * failed. */
 443         r = safe_fork("(sd-umount)", FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_LOG|FORK_REOPEN_LOG, &pid);
 444         if (r < 0)
 445                 return r;
 446         if (r == 0) {
 447                 log_info("Unmounting '%s'.", m->path);
 448
 449                 /* Start the mount operation here in the child Using MNT_FORCE
 450                  * causes some filesystems (e.g. FUSE and NFS and other network
 451                  * filesystems) to abort any pending requests and return -EIO
 452                  * rather than blocking indefinitely. If the filesysten is
 453                  * "busy", this may allow processes to die, thus making the
 454                  * filesystem less busy so the unmount might succeed (rather
 455                  * then return EBUSY).*/
 456                 r = umount2(m->path, MNT_FORCE);
 457                 if (r < 0)
 458                         log_full_errno(umount_log_level, errno, "Failed to unmount %s: %m", m->path);
 459
 460                 _exit(r < 0 ? EXIT_FAILURE : EXIT_SUCCESS);
 461         }
 462
 463         r = wait_for_terminate_with_timeout(pid, DEFAULT_TIMEOUT_USEC);
 464         if (r == -ETIMEDOUT) {
 465                 log_error_errno(r, "Unmounting '%s' timed out, issuing SIGKILL to PID " PID_FMT ".", m->path, pid);
 466                 (void) kill(pid, SIGKILL);
 467         } else if (r == -EPROTO)
 468                 log_debug_errno(r, "Unmounting '%s' failed abnormally, child process " PID_FMT " aborted or exited non-zero.", m->path, pid);
 469         else if (r < 0)
 470                 log_error_errno(r, "Unmounting '%s' failed unexpectedly, couldn't wait for child process " PID_FMT ": %m", m->path, pid);
 471
 472         return r;
 473 }
 474
 475 /* This includes remounting readonly, which changes the kernel mount options.
 476  * Therefore the list passed to this function is invalidated, and should not be reused. */
 477 static int mount_points_list_umount(MountPoint **head, bool *changed, int umount_log_level) {
 478         MountPoint *m;
 479         int n_failed = 0;
 480
 481         assert(head);
 482         assert(changed);
 483
 484         LIST_FOREACH(mount_point, m, *head) {
 485                 if (m->try_remount_ro) {
 486                         /* We always try to remount directories
 487                          * read-only first, before we go on and umount
 488                          * them.
 489                          *
 490                          * Mount points can be stacked. If a mount
 491                          * point is stacked below / or /usr, we
 492                          * cannot umount or remount it directly,
 493                          * since there is no way to refer to the
 494                          * underlying mount. There's nothing we can do
 495                          * about it for the general case, but we can
 496                          * do something about it if it is aliased
 497                          * somehwere else via a bind mount. If we
 498                          * explicitly remount the super block of that
 499                          * alias read-only we hence should be
 500                          * relatively safe regarding keeping a dirty fs
 501                          * we cannot otherwise see.
 502                          *
 503                          * Since the remount can hang in the instance of
 504                          * remote filesystems, we remount asynchronously
 505                          * and skip the subsequent umount if it fails. */
 506                         if (remount_with_timeout(m, umount_log_level) < 0) {
 507                                 /* Remount failed, but try unmounting anyway,
 508                                  * unless this is a mount point we want to skip. */
 509                                 if (nonunmountable_path(m->path)) {
 510                                         n_failed++;
 511                                         continue;
 512                                 }
 513                         }
 514                 }
 515
 516                 /* Skip / and /usr since we cannot unmount that
 517                  * anyway, since we are running from it. They have
 518                  * already been remounted ro. */
 519                 if (nonunmountable_path(m->path))
 520                         continue;
 521
 522                 /* Trying to umount */
 523                 if (umount_with_timeout(m, umount_log_level) < 0)
 524                         n_failed++;
 525                 else
 526                         *changed = true;
 527         }
 528
 529         return n_failed;
 530 }
 531
 532 static int swap_points_list_off(MountPoint **head, bool *changed) {
 533         MountPoint *m, *n;
 534         int n_failed = 0;
 535
 536         assert(head);
 537         assert(changed);
 538
 539         LIST_FOREACH_SAFE(mount_point, m, n, *head) {
 540                 log_info("Deactivating swap %s.", m->path);
 541                 if (swapoff(m->path) == 0) {
 542                         *changed = true;
 543                         mount_point_free(head, m);
 544                 } else {
 545                         log_warning_errno(errno, "Could not deactivate swap %s: %m", m->path);
 546                         n_failed++;
 547                 }
 548         }
 549
 550         return n_failed;
 551 }
 552
 553 static int loopback_points_list_detach(MountPoint **head, bool *changed, int umount_log_level) {
 554         MountPoint *m, *n;
 555         int n_failed = 0, k;
 556         struct stat root_st;
 557
 558         assert(head);
 559         assert(changed);
 560
 561         k = lstat("/", &root_st);
 562
 563         LIST_FOREACH_SAFE(mount_point, m, n, *head) {
 564                 int r;
 565                 struct stat loopback_st;
 566
 567                 if (k >= 0 &&
 568                     major(root_st.st_dev) != 0 &&
 569                     lstat(m->path, &loopback_st) >= 0 &&
 570                     root_st.st_dev == loopback_st.st_rdev) {
 571                         n_failed++;
 572                         continue;
 573                 }
 574
 575                 log_info("Detaching loopback %s.", m->path);
 576                 r = delete_loopback(m->path);
 577                 if (r >= 0) {
 578                         if (r > 0)
 579                                 *changed = true;
 580
 581                         mount_point_free(head, m);
 582                 } else {
 583                         log_full_errno(umount_log_level, errno, "Could not detach loopback %s: %m", m->path);
 584                         n_failed++;
 585                 }
 586         }
 587
 588         return n_failed;
 589 }
 590
 591 static int dm_points_list_detach(MountPoint **head, bool *changed, int umount_log_level) {
 592         MountPoint *m, *n;
 593         int n_failed = 0, r;
 594         dev_t rootdev;
 595
 596         assert(head);
 597         assert(changed);
 598
 599         r = get_block_device("/", &rootdev);
 600         if (r <= 0)
 601                 rootdev = 0;
 602
 603         LIST_FOREACH_SAFE(mount_point, m, n, *head) {
 604
 605                 if (major(rootdev) != 0 && rootdev == m->devnum) {
 606                         n_failed ++;
 607                         continue;
 608                 }
 609
 610                 log_info("Detaching DM %u:%u.", major(m->devnum), minor(m->devnum));
 611                 r = delete_dm(m->devnum);
 612                 if (r >= 0) {
 613                         *changed = true;
 614                         mount_point_free(head, m);
 615                 } else {
 616                         log_full_errno(umount_log_level, errno, "Could not detach DM %s: %m", m->path);
 617                         n_failed++;
 618                 }
 619         }
 620
 621         return n_failed;
 622 }
 623
 624 static int umount_all_once(bool *changed, int umount_log_level) {
 625         int r;
 626         _cleanup_(mount_points_list_free) LIST_HEAD(MountPoint, mp_list_head);
 627
 628         assert(changed);
 629
 630         LIST_HEAD_INIT(mp_list_head);
 631         r = mount_points_list_get(NULL, &mp_list_head);
 632         if (r < 0)
 633                 return r;
 634
 635         return mount_points_list_umount(&mp_list_head, changed, umount_log_level);
 636 }
 637
 638 int umount_all(bool *changed, int umount_log_level) {
 639         bool umount_changed;
 640         int r;
 641
 642         assert(changed);
 643
 644         /* Retry umount, until nothing can be umounted anymore. Mounts are
 645          * processed in order, newest first. The retries are needed when
 646          * an old mount has been moved, to a path inside a newer mount. */
 647         do {
 648                 umount_changed = false;
 649
 650                 r = umount_all_once(&umount_changed, umount_log_level);
 651                 if (umount_changed)
 652                         *changed = true;
 653         } while (umount_changed);
 654
 655         return r;
 656 }
 657
 658 int swapoff_all(bool *changed) {
 659         _cleanup_(mount_points_list_free) LIST_HEAD(MountPoint, swap_list_head);
 660         int r;
 661
 662         assert(changed);
 663
 664         LIST_HEAD_INIT(swap_list_head);
 665
 666         r = swap_list_get(NULL, &swap_list_head);
 667         if (r < 0)
 668                 return r;
 669
 670         return swap_points_list_off(&swap_list_head, changed);
 671 }
 672
 673 int loopback_detach_all(bool *changed, int umount_log_level) {
 674         _cleanup_(mount_points_list_free) LIST_HEAD(MountPoint, loopback_list_head);
 675         int r;
 676
 677         assert(changed);
 678
 679         LIST_HEAD_INIT(loopback_list_head);
 680
 681         r = loopback_list_get(&loopback_list_head);
 682         if (r < 0)
 683                 return r;
 684
 685         return loopback_points_list_detach(&loopback_list_head, changed, umount_log_level);
 686 }
 687
 688 int dm_detach_all(bool *changed, int umount_log_level) {
 689         _cleanup_(mount_points_list_free) LIST_HEAD(MountPoint, dm_list_head);
 690         int r;
 691
 692         assert(changed);
 693
 694         LIST_HEAD_INIT(dm_list_head);
 695
 696         r = dm_list_get(&dm_list_head);
 697         if (r < 0)
 698                 return r;
 699
 700         return dm_points_list_detach(&dm_list_head, changed, umount_log_level);
 701 }