chiark / gitweb /
core: more exact test on the procfs special string "(deleted)"
[elogind.git] / src / core / umount.c
index 83c9de3e8298635d8c2736a67cd71a932dbe9a2b..2d166c1c92c967a69f6d060b3b8c5c8bc15faf67 100644 (file)
@@ -27,7 +27,6 @@
 #include <unistd.h>
 #include <linux/loop.h>
 #include <linux/dm-ioctl.h>
-#include <libudev.h>
 
 #include "list.h"
 #include "mount-setup.h"
 #include "path-util.h"
 #include "util.h"
 #include "virt.h"
+#include "libudev.h"
+#include "udev-util.h"
 
 typedef struct MountPoint {
         char *path;
         dev_t devnum;
-        LIST_FIELDS (struct MountPoint, mount_point);
+        LIST_FIELDS(struct MountPoint, mount_point);
 } MountPoint;
 
 static void mount_point_free(MountPoint **head, MountPoint *m) {
         assert(head);
         assert(m);
 
-        LIST_REMOVE(MountPoint, mount_point, *head, m);
+        LIST_REMOVE(mount_point, *head, m);
 
         free(m->path);
         free(m);
@@ -124,7 +125,7 @@ static int mount_points_list_get(MountPoint **head) {
                 }
 
                 m->path = p;
-                LIST_PREPEND(MountPoint, mount_point, *head, m);
+                LIST_PREPEND(mount_point, *head, m);
         }
 
         r = 0;
@@ -169,7 +170,7 @@ static int swap_list_get(MountPoint **head) {
                         continue;
                 }
 
-                if (endswith(dev, "(deleted)")) {
+                if (endswith(dev, " (deleted)")) {
                         free(dev);
                         continue;
                 }
@@ -189,7 +190,7 @@ static int swap_list_get(MountPoint **head) {
                 }
 
                 swap->path = d;
-                LIST_PREPEND(MountPoint, mount_point, *head, swap);
+                LIST_PREPEND(mount_point, *head, swap);
         }
 
         r = 0;
@@ -201,161 +202,130 @@ finish:
 }
 
 static int loopback_list_get(MountPoint **head) {
-        int r;
-        struct udev *udev;
-        struct udev_enumerate *e = NULL;
+        _cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL;
         struct udev_list_entry *item = NULL, *first = NULL;
+        _cleanup_udev_unref_ struct udev *udev = NULL;
+        int r;
 
         assert(head);
 
-        if (!(udev = udev_new())) {
-                r = -ENOMEM;
-                goto finish;
-        }
+        udev = udev_new();
+        if (!udev)
+                return -ENOMEM;
 
-        if (!(e = udev_enumerate_new(udev))) {
-                r = -ENOMEM;
-                goto finish;
-        }
+        e = udev_enumerate_new(udev);
+        if (!e)
+                return -ENOMEM;
 
-        if (udev_enumerate_add_match_subsystem(e, "block") < 0 ||
-            udev_enumerate_add_match_sysname(e, "loop*") < 0) {
-                r = -EIO;
-                goto finish;
-        }
+        r = udev_enumerate_add_match_subsystem(e, "block");
+        if (r < 0)
+                return r;
 
-        if (udev_enumerate_scan_devices(e) < 0) {
-                r = -EIO;
-                goto finish;
-        }
+        r = udev_enumerate_add_match_sysname(e, "loop*");
+        if (r < 0)
+                return r;
+
+        r = udev_enumerate_add_match_sysattr(e, "loop/backing_file", NULL);
+        if (r < 0)
+                return r;
+
+        r = udev_enumerate_scan_devices(e);
+        if (r < 0)
+                return r;
 
         first = udev_enumerate_get_list_entry(e);
         udev_list_entry_foreach(item, first) {
                 MountPoint *lb;
-                struct udev_device *d;
+                _cleanup_udev_device_unref_ struct udev_device *d;
                 char *loop;
                 const char *dn;
 
-                if (!(d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item)))) {
-                        r = -ENOMEM;
-                        goto finish;
-                }
+                d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item));
+                if (!d)
+                        return -ENOMEM;
 
-                if (!(dn = udev_device_get_devnode(d))) {
-                        udev_device_unref(d);
+                dn = udev_device_get_devnode(d);
+                if (!dn)
                         continue;
-                }
 
                 loop = strdup(dn);
-                udev_device_unref(d);
+                if (!loop)
+                        return -ENOMEM;
 
-                if (!loop) {
-                        r = -ENOMEM;
-                        goto finish;
-                }
-
-                if (!(lb = new0(MountPoint, 1))) {
+                lb = new0(MountPoint, 1);
+                if (!lb) {
                         free(loop);
-                        r = -ENOMEM;
-                        goto finish;
+                        return -ENOMEM;
                 }
 
                 lb->path = loop;
-                LIST_PREPEND(MountPoint, mount_point, *head, lb);
+                LIST_PREPEND(mount_point, *head, lb);
         }
 
-        r = 0;
-
-finish:
-        if (e)
-                udev_enumerate_unref(e);
-
-        if (udev)
-                udev_unref(udev);
-
-        return r;
+        return 0;
 }
 
 static int dm_list_get(MountPoint **head) {
-        int r;
-        struct udev *udev;
-        struct udev_enumerate *e = NULL;
+        _cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL;
         struct udev_list_entry *item = NULL, *first = NULL;
+        _cleanup_udev_unref_ struct udev *udev = NULL;
+        int r;
 
         assert(head);
 
-        if (!(udev = udev_new())) {
-                r = -ENOMEM;
-                goto finish;
-        }
+        udev = udev_new();
+        if (!udev)
+                return -ENOMEM;
 
-        if (!(e = udev_enumerate_new(udev))) {
-                r = -ENOMEM;
-                goto finish;
-        }
+        e = udev_enumerate_new(udev);
+        if (!e)
+                return -ENOMEM;
 
-        if (udev_enumerate_add_match_subsystem(e, "block") < 0 ||
-            udev_enumerate_add_match_sysname(e, "dm-*") < 0) {
-                r = -EIO;
-                goto finish;
-        }
+        r = udev_enumerate_add_match_subsystem(e, "block");
+        if (r < 0)
+                return r;
 
-        if (udev_enumerate_scan_devices(e) < 0) {
-                r = -EIO;
-                goto finish;
-        }
+        r = udev_enumerate_add_match_sysname(e, "dm-*");
+        if (r < 0)
+                return r;
 
-        first = udev_enumerate_get_list_entry(e);
+        r = udev_enumerate_scan_devices(e);
+        if (r < 0)
+                return r;
 
+        first = udev_enumerate_get_list_entry(e);
         udev_list_entry_foreach(item, first) {
                 MountPoint *m;
-                struct udev_device *d;
+                _cleanup_udev_device_unref_ struct udev_device *d;
                 dev_t devnum;
                 char *node;
                 const char *dn;
 
-                if (!(d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item)))) {
-                        r = -ENOMEM;
-                        goto finish;
-                }
+                d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item));
+                if (!d)
+                        return -ENOMEM;
 
                 devnum = udev_device_get_devnum(d);
                 dn = udev_device_get_devnode(d);
-
-                if (major(devnum) == 0 || !dn) {
-                        udev_device_unref(d);
+                if (major(devnum) == 0 || !dn)
                         continue;
-                }
 
                 node = strdup(dn);
-                udev_device_unref(d);
-
-                if (!node) {
-                        r = -ENOMEM;
-                        goto finish;
-                }
+                if (!node)
+                        return -ENOMEM;
 
-                if (!(m = new(MountPoint, 1))) {
+                m = new(MountPoint, 1);
+                if (!m) {
                         free(node);
-                        r = -ENOMEM;
-                        goto finish;
+                        return -ENOMEM;
                 }
 
                 m->path = node;
                 m->devnum = devnum;
-                LIST_PREPEND(MountPoint, mount_point, *head, m);
+                LIST_PREPEND(mount_point, *head, m);
         }
 
-        r = 0;
-
-finish:
-        if (e)
-                udev_enumerate_unref(e);
-
-        if (udev)
-                udev_unref(udev);
-
-        return r;
+        return 0;
 }
 
 static int delete_loopback(const char *device) {
@@ -378,25 +348,23 @@ static int delete_loopback(const char *device) {
 }
 
 static int delete_dm(dev_t devnum) {
-        int fd, r;
-        struct dm_ioctl dm;
+        _cleanup_close_ int fd = -1;
+        int r;
+        struct dm_ioctl dm = {
+                .version = {DM_VERSION_MAJOR,
+                            DM_VERSION_MINOR,
+                            DM_VERSION_PATCHLEVEL},
+                .data_size = sizeof(dm),
+                .dev = devnum,
+        };
 
         assert(major(devnum) != 0);
 
-        if ((fd = open("/dev/mapper/control", O_RDWR|O_CLOEXEC)) < 0)
+        fd = open("/dev/mapper/control", O_RDWR|O_CLOEXEC);
+        if (fd < 0)
                 return -errno;
 
-        zero(dm);
-        dm.version[0] = DM_VERSION_MAJOR;
-        dm.version[1] = DM_VERSION_MINOR;
-        dm.version[2] = DM_VERSION_PATCHLEVEL;
-
-        dm.data_size = sizeof(dm);
-        dm.dev = devnum;
-
         r = ioctl(fd, DM_DEV_REMOVE, &dm);
-        close_nointr_nofail(fd);
-
         return r >= 0 ? 0 : -errno;
 }
 
@@ -407,18 +375,46 @@ 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
+                         * cannot 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) */
-                if (umount2(m->path, MNT_FORCE) == 0) {
-                        log_info("Unmounted %s.", m->path);
+                /* Trying to umount. We don't force here since we rely
+                 * on busy NFS and FUSE file systems to return EBUSY
+                 * until we closed everything on top of them. */
+                log_info("Unmounting %s.", m->path);
+                if (umount2(m->path, 0) == 0) {
                         if (changed)
                                 *changed = true;
 
@@ -432,29 +428,6 @@ 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;
@@ -462,6 +435,7 @@ 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;
@@ -497,14 +471,15 @@ 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++;
                 }
         }
@@ -531,14 +506,15 @@ 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++;
                 }
         }
@@ -551,7 +527,7 @@ int umount_all(bool *changed) {
         bool umount_changed;
         LIST_HEAD(MountPoint, mp_list_head);
 
-        LIST_HEAD_INIT(MountPoint, mp_list_head);
+        LIST_HEAD_INIT(mp_list_head);
         r = mount_points_list_get(&mp_list_head);
         if (r < 0)
                 goto end;
@@ -571,13 +547,6 @@ 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);
 
@@ -588,7 +557,7 @@ int swapoff_all(bool *changed) {
         int r;
         LIST_HEAD(MountPoint, swap_list_head);
 
-        LIST_HEAD_INIT(MountPoint, swap_list_head);
+        LIST_HEAD_INIT(swap_list_head);
 
         r = swap_list_get(&swap_list_head);
         if (r < 0)
@@ -606,7 +575,7 @@ int loopback_detach_all(bool *changed) {
         int r;
         LIST_HEAD(MountPoint, loopback_list_head);
 
-        LIST_HEAD_INIT(MountPoint, loopback_list_head);
+        LIST_HEAD_INIT(loopback_list_head);
 
         r = loopback_list_get(&loopback_list_head);
         if (r < 0)
@@ -624,7 +593,7 @@ int dm_detach_all(bool *changed) {
         int r;
         LIST_HEAD(MountPoint, dm_list_head);
 
-        LIST_HEAD_INIT(MountPoint, dm_list_head);
+        LIST_HEAD_INIT(dm_list_head);
 
         r = dm_list_get(&dm_list_head);
         if (r < 0)