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Merge pull request #14409 from poettering/shutdown-modernization

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some smaller modernizations to the shutdown loop
This commit is contained in:
Zbigniew Jędrzejewski-Szmek
2019-12-21 19:21:10 +01:00
committed by GitHub
parent 3c4ddf5db5 4ca8072fd6
commit 1234d0f63e
1 changed files with 89 additions and 63 deletions
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src/shutdown/umount.c
+89 -63
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@@ -249,8 +249,10 @@ static int loopback_list_get(MountPoint **head) {
_cleanup_free_ char *p = NULL;
const char *dn;
MountPoint *lb;
dev_t devnum;
if (sd_device_get_devname(d, &dn) < 0)
if (sd_device_get_devnum(d, &devnum) < 0 ||
sd_device_get_devname(d, &dn) < 0)
continue;
p = strdup(dn);
@@ -263,6 +265,7 @@ static int loopback_list_get(MountPoint **head) {
*lb = (MountPoint) {
.path = TAKE_PTR(p),
.devnum = devnum,
};
LIST_PREPEND(mount_point, *head, lb);
@@ -325,7 +328,7 @@ static int dm_list_get(MountPoint **head) {
static int delete_loopback(const char *device) {
_cleanup_close_ int fd = -1;
int r;
struct loop_info64 info;
assert(device);
@@ -333,15 +336,54 @@ static int delete_loopback(const char *device) {
if (fd < 0)
return errno == ENOENT ? 0 : -errno;
r = ioctl(fd, LOOP_CLR_FD, 0);
if (r >= 0)
if (ioctl(fd, LOOP_CLR_FD, 0) < 0) {
if (errno == ENXIO) /* Nothing bound, didn't do anything */
return 0;
if (errno != EBUSY)
return log_debug_errno(errno, "Failed to clear loopback device %s: %m", device);
if (ioctl(fd, LOOP_GET_STATUS64, &info) < 0) {
if (errno == ENXIO) /* What? Suddenly detached after all? That's fine by us then. */
return 1;
log_debug_errno(errno, "Failed to invoke LOOP_GET_STATUS64 on loopback device %s, ignoring: %m", device);
return -EBUSY; /* propagate original error */
}
if (FLAGS_SET(info.lo_flags, LO_FLAGS_AUTOCLEAR)) /* someone else already set LO_FLAGS_AUTOCLEAR for us? fine by us */
return -EBUSY; /* propagate original error */
info.lo_flags |= LO_FLAGS_AUTOCLEAR;
if (ioctl(fd, LOOP_SET_STATUS64, &info) < 0) {
if (errno == ENXIO) /* Suddenly detached after all? Fine by us */
return 1;
log_debug_errno(errno, "Failed to set LO_FLAGS_AUTOCLEAR flag for loop device %s, ignoring: %m", device);
} else
log_debug("Successfully set LO_FLAGS_AUTOCLEAR flag for loop device %s.", device);
return -EBUSY;
}
if (ioctl(fd, LOOP_GET_STATUS64, &info) < 0) {
/* If the LOOP_CLR_FD above succeeded we'll see ENXIO here. */
if (errno == ENXIO)
log_debug("Successfully detached loopback device %s.", device);
else
log_debug_errno(errno, "Failed to invoke LOOP_GET_STATUS64 on loopback device %s, ignoring: %m", device); /* the LOOP_CLR_FD at least worked, let's hope for the best */
return 1;
}
/* ENXIO: not bound, so no error */
if (errno == ENXIO)
return 0;
/* Linux makes LOOP_CLR_FD succeed whenever LO_FLAGS_AUTOCLEAR is set without actually doing
* anything. Very confusing. Let's hence not claim we did anything in this case. */
if (FLAGS_SET(info.lo_flags, LO_FLAGS_AUTOCLEAR))
log_debug("Successfully called LOOP_CLR_FD on a loopback device %s with autoclear set, which is a NOP.", device);
else
log_debug("Weird, LOOP_CLR_FD succeeded but the device is still attached on %s.", device);
return -errno;
return -EBUSY; /* Nothing changed, the device is still attached, hence it apparently is still busy */
}
static int delete_dm(dev_t devnum) {
@@ -460,8 +502,8 @@ static int umount_with_timeout(MountPoint *m, int umount_log_level) {
return r;
}
/* This includes remounting readonly, which changes the kernel mount options.
* Therefore the list passed to this function is invalidated, and should not be reused. */
/* This includes remounting readonly, which changes the kernel mount options. Therefore the list passed to
* this function is invalidated, and should not be reused. */
static int mount_points_list_umount(MountPoint **head, bool *changed, int umount_log_level) {
MountPoint *m;
int n_failed = 0;
@@ -471,26 +513,18 @@ static int mount_points_list_umount(MountPoint **head, bool *changed, int umount
LIST_FOREACH(mount_point, m, *head) {
if (m->try_remount_ro) {
/* We always try to remount directories
* read-only first, before we go on and umount
/* 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
* somewhere 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 a dirty fs
* we cannot otherwise see.
* 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 somewhere 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 a dirty fs we cannot otherwise see.
*
* Since the remount can hang in the instance of
* remote filesystems, we remount asynchronously
* and skip the subsequent umount if it fails. */
* Since the remount can hang in the instance of remote filesystems, we remount
* asynchronously and skip the subsequent umount if it fails. */
if (remount_with_timeout(m, umount_log_level) < 0) {
/* Remount failed, but try unmounting anyway,
* unless this is a mount point we want to skip. */
@@ -501,9 +535,8 @@ static int mount_points_list_umount(MountPoint **head, bool *changed, int umount
}
}
/* Skip / and /usr since we cannot unmount that
* anyway, since we are running from it. They have
* already been remounted ro. */
/* Skip / and /usr since we cannot unmount that anyway, since we are running from it. They
* have already been remounted ro. */
if (nonunmountable_path(m->path))
continue;
@@ -526,13 +559,14 @@ static int swap_points_list_off(MountPoint **head, bool *changed) {
LIST_FOREACH_SAFE(mount_point, m, n, *head) {
log_info("Deactivating swap %s.", m->path);
if (swapoff(m->path) == 0) {
*changed = true;
mount_point_free(head, m);
} else {
if (swapoff(m->path) < 0) {
log_warning_errno(errno, "Could not deactivate swap %s: %m", m->path);
n_failed++;
continue;
}
*changed = true;
mount_point_free(head, m);
}
return n_failed;
@@ -540,37 +574,31 @@ static int swap_points_list_off(MountPoint **head, bool *changed) {
static int loopback_points_list_detach(MountPoint **head, bool *changed, int umount_log_level) {
MountPoint *m, *n;
int n_failed = 0, k;
struct stat root_st;
int n_failed = 0, r;
dev_t rootdev = 0;
assert(head);
assert(changed);
k = lstat("/", &root_st);
(void) get_block_device("/", &rootdev);
LIST_FOREACH_SAFE(mount_point, m, n, *head) {
int r;
struct stat loopback_st;
if (k >= 0 &&
major(root_st.st_dev) != 0 &&
lstat(m->path, &loopback_st) >= 0 &&
root_st.st_dev == loopback_st.st_rdev) {
if (major(rootdev) != 0 && rootdev == m->devnum) {
n_failed++;
continue;
}
log_info("Detaching loopback %s.", m->path);
r = delete_loopback(m->path);
if (r >= 0) {
if (r > 0)
*changed = true;
mount_point_free(head, m);
} else {
log_full_errno(umount_log_level, errno, "Could not detach loopback %s: %m", m->path);
if (r < 0) {
log_full_errno(umount_log_level, r, "Could not detach loopback %s: %m", m->path);
n_failed++;
continue;
}
if (r > 0)
*changed = true;
mount_point_free(head, m);
}
return n_failed;
@@ -579,39 +607,37 @@ static int loopback_points_list_detach(MountPoint **head, bool *changed, int umo
static int dm_points_list_detach(MountPoint **head, bool *changed, int umount_log_level) {
MountPoint *m, *n;
int n_failed = 0, r;
dev_t rootdev;
dev_t rootdev = 0;
assert(head);
assert(changed);
r = get_block_device("/", &rootdev);
if (r <= 0)
rootdev = 0;
(void) get_block_device("/", &rootdev);
LIST_FOREACH_SAFE(mount_point, m, n, *head) {
if (major(rootdev) != 0 && rootdev == m->devnum) {
n_failed ++;
continue;
}
log_info("Detaching DM %u:%u.", major(m->devnum), minor(m->devnum));
log_info("Detaching DM %s (%u:%u).", m->path, major(m->devnum), minor(m->devnum));
r = delete_dm(m->devnum);
if (r >= 0) {
*changed = true;
mount_point_free(head, m);
} else {
log_full_errno(umount_log_level, errno, "Could not detach DM %s: %m", m->path);
if (r < 0) {
log_full_errno(umount_log_level, r, "Could not detach DM %s: %m", m->path);
n_failed++;
continue;
}
*changed = true;
mount_point_free(head, m);
}
return n_failed;
}
static int umount_all_once(bool *changed, int umount_log_level) {
int r;
_cleanup_(mount_points_list_free) LIST_HEAD(MountPoint, mp_list_head);
int r;
assert(changed);