65 lines
4.0 KiB
Diff
65 lines
4.0 KiB
Diff
From 54a4d71509c0f3401aa576346754a0781795214a Mon Sep 17 00:00:00 2001
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From: Yu Watanabe <watanabe.yu+github@gmail.com>
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Date: Tue, 25 Oct 2022 21:40:21 +0900
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Subject: [PATCH] core/device: update comment
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---
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src/core/device.c | 29 +++++++++++++++++------------
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1 file changed, 17 insertions(+), 12 deletions(-)
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diff --git a/src/core/device.c b/src/core/device.c
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index 0bca0ff..9d694aa 100644
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--- a/src/core/device.c
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+++ b/src/core/device.c
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@@ -172,7 +172,7 @@ static int device_coldplug(Unit *u) {
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* 1. MANAGER_IS_RUNNING() == false
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* 2. enumerate devices: manager_enumerate() -> device_enumerate()
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* Device.enumerated_found is set.
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- * 3. deserialize devices: manager_deserialize() -> device_deserialize()
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+ * 3. deserialize devices: manager_deserialize() -> device_deserialize_item()
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* Device.deserialize_state and Device.deserialized_found are set.
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* 4. coldplug devices: manager_coldplug() -> device_coldplug()
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* deserialized properties are copied to the main properties.
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@@ -187,22 +187,27 @@ static int device_coldplug(Unit *u) {
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*
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* - On switch-root, the udev databse may be cleared, except for devices with sticky bit, i.e.
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* OPTIONS="db_persist". Hence, almost no devices are enumerated in the step 2. However, in general,
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- * we have several serialized devices. So, DEVICE_FOUND_UDEV bit in the deserialized_found must be
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- * ignored, as udev rules in initramfs and the main system are often different. If the deserialized
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- * state is DEVICE_PLUGGED, we need to downgrade it to DEVICE_TENTATIVE. Unlike the other starting
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- * mode, MANAGER_IS_SWITCHING_ROOT() is true when device_coldplug() and device_catchup() are called.
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- * Hence, let's conditionalize the operations by using the flag. After switch-root, systemd-udevd
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- * will (re-)process all devices, and the Device.found and Device.state will be adjusted.
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+ * we have several serialized devices. So, DEVICE_FOUND_UDEV bit in the
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+ * Device.deserialized_found must be ignored, as udev rules in initrd and the main system are often
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+ * different. If the deserialized state is DEVICE_PLUGGED, we need to downgrade it to
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+ * DEVICE_TENTATIVE. Unlike the other starting mode, MANAGER_IS_SWITCHING_ROOT() is true when
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+ * device_coldplug() and device_catchup() are called. Hence, let's conditionalize the operations by
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+ * using the flag. After switch-root, systemd-udevd will (re-)process all devices, and the
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+ * Device.found and Device.state will be adjusted.
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*
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- * - On reload or reexecute, we can trust enumerated_found, deserialized_found, and deserialized_state.
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- * Of course, deserialized parameters may be outdated, but the unit state can be adjusted later by
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- * device_catchup() or uevents. */
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+ * - On reload or reexecute, we can trust Device.enumerated_found, Device.deserialized_found, and
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+ * Device.deserialized_state. Of course, deserialized parameters may be outdated, but the unit
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+ * state can be adjusted later by device_catchup() or uevents. */
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if (MANAGER_IS_SWITCHING_ROOT(m) &&
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!FLAGS_SET(d->enumerated_found, DEVICE_FOUND_UDEV)) {
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- found &= ~DEVICE_FOUND_UDEV; /* ignore DEVICE_FOUND_UDEV bit */
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+ /* The device has not been enumerated. On switching-root, such situation is natural. See the
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+ * above comment. To prevent problematic state transition active → dead → active, let's
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+ * drop the DEVICE_FOUND_UDEV flag and downgrade state to DEVICE_TENTATIVE(activating). See
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+ * issue #12953 and #23208. */
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+ found &= ~DEVICE_FOUND_UDEV;
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if (state == DEVICE_PLUGGED)
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- state = DEVICE_TENTATIVE; /* downgrade state */
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+ state = DEVICE_TENTATIVE;
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}
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if (d->found == found && d->state == state)
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--
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2.33.0
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