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core/device: ignore DEVICE_FOUND_UDEV bit on switching root

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The issue #12953 is caused by the following:
On switching root,
- deserialized_found == DEVICE_FOUND_UDEV | DEVICE_FOUND_MOUNT,
- deserialized_state == DEVICE_PLUGGED,
- enumerated_found == DEVICE_FOUND_MOUNT,
On switching root, most devices are not found by the enumeration process.
Hence, the device state is set to plugged by device_coldplug(), and then
changed to the dead state in device_catchup(). So the corresponding
mount point is unmounted. Later when the device is processed by udevd, it
will be changed to plugged state again.

The issue #23208 is caused by the fact that generated udev database in
initramfs and the main system are often different.

So, the two issues have the same root; we should not honor
DEVICE_FOUND_UDEV bit in the deserialized_found on switching root.

This partially reverts c6e892bc0e.

Fixes #12953 and #23208.
Replaces #23215.

Co-authored-by: Martin Wilck <mwilck@suse.com>
This commit is contained in:
Yu Watanabe 2022-04-29 20:29:11 +09:00
parent f33bc87989
commit 75d7b5989f
1 changed files with 50 additions and 11 deletions
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61
src/core/device.c
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@ -163,14 +163,57 @@ static int device_coldplug(Unit *u) {
assert(d->state == DEVICE_DEAD);
/* First, let's put the deserialized state and found mask into effect, if we have it. */
if (d->deserialized_state < 0 ||
(d->deserialized_state == d->state &&
d->deserialized_found == d->found))
if (d->deserialized_state < 0)
return 0;
d->found = d->deserialized_found;
device_set_state(d, d->deserialized_state);
Manager *m = u->manager;
DeviceFound found = d->deserialized_found;
DeviceState state = d->deserialized_state;
/* On initial boot, switch-root, reload, reexecute, the following happen:
* 1. MANAGER_IS_RUNNING() == false
* 2. enumerate devices: manager_enumerate() -> device_enumerate()
* Device.enumerated_found is set.
* 3. deserialize devices: manager_deserialize() -> device_deserialize()
* Device.deserialize_state and Device.deserialized_found are set.
* 4. coldplug devices: manager_coldplug() -> device_coldplug()
* deserialized properties are copied to the main properties.
* 5. MANAGER_IS_RUNNING() == true: manager_ready()
* 6. catchup devices: manager_catchup() -> device_catchup()
* Device.enumerated_found is applied to Device.found, and state is updated based on that.
*
* Notes:
* - On initial boot, no udev database exists. Hence, no devices are enumerated in the step 2.
* Also, there is no deserialized device. Device units are (a) generated based on dependencies of
* other units, or (b) generated when uevents are received.
*
* - On switch-root, the udev databse may be cleared, except for devices with sticky bit, i.e.
* OPTIONS="db_persist". Hence, almost no devices are enumerated in the step 2. However, in general,
* we have several serialized devices. So, DEVICE_FOUND_UDEV bit in the deserialized_found must be
* ignored, as udev rules in initramfs and the main system are often different. If the deserialized
* state is DEVICE_PLUGGED, we need to downgrade it to DEVICE_TENTATIVE (or DEVICE_DEAD if nobody
* sees the device). Unlike the other starting mode, Manager.honor_device_enumeration == false
* (maybe, it is better to rename the flag) when device_coldplug() and device_catchup() are called.
* Hence, let's conditionalize the operations by using the flag. After switch-root, systemd-udevd
* will (re-)process all devices, and the Device.found and Device.state will be adjusted.
*
* - On reload or reexecute, we can trust enumerated_found, deserialized_found, and deserialized_state.
* Of course, deserialized parameters may be outdated, but the unit state can be adjusted later by
* device_catchup() or uevents. */
if (!m->honor_device_enumeration && !MANAGER_IS_USER(m)) {
found &= ~DEVICE_FOUND_UDEV; /* ignore DEVICE_FOUND_UDEV bit */
if (state == DEVICE_PLUGGED)
state = DEVICE_TENTATIVE; /* downgrade state */
if (found == DEVICE_NOT_FOUND)
state = DEVICE_DEAD; /* If nobody sees the device, downgrade more */
}
if (d->found == found && d->state == state)
return 0;
d->found = found;
device_set_state(d, state);
return 0;
}
@ -644,13 +687,9 @@ static void device_found_changed(Device *d, DeviceFound previous, DeviceFound no
}
static void device_update_found_one(Device *d, DeviceFound found, DeviceFound mask) {
Manager *m;
assert(d);
m = UNIT(d)->manager;
if (MANAGER_IS_RUNNING(m) && (m->honor_device_enumeration || MANAGER_IS_USER(m))) {
if (MANAGER_IS_RUNNING(UNIT(d)->manager)) {
DeviceFound n, previous;
/* When we are already running, then apply the new mask right-away, and trigger state changes