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tcmur_device.c
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tcmur_device.c
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/*
* Copyright 2017, Red Hat, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License. You may obtain
* a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <inttypes.h>
#include <pthread.h>
#include <errno.h>
#include <unistd.h>
#include "libtcmu_log.h"
#include "libtcmu_common.h"
#include "tcmu-runner.h"
#include "tcmur_device.h"
#include "target.h"
bool tcmu_dev_in_recovery(struct tcmu_device *dev)
{
struct tcmur_device *rdev = tcmu_get_daemon_dev_private(dev);
int in_recov = false;
pthread_mutex_lock(&rdev->state_lock);
if (rdev->flags & TCMUR_DEV_FLAG_IN_RECOVERY)
in_recov = true;
pthread_mutex_unlock(&rdev->state_lock);
return in_recov;
}
/*
* TCMUR_DEV_FLAG_IN_RECOVERY must be set before calling
*/
int __tcmu_reopen_dev(struct tcmu_device *dev)
{
struct tcmur_device *rdev = tcmu_get_daemon_dev_private(dev);
struct tcmur_handler *rhandler = tcmu_get_runner_handler(dev);
int ret;
tcmu_dev_dbg(dev, "Waiting for outstanding commands to complete\n");
ret = aio_wait_for_empty_queue(rdev);
pthread_mutex_lock(&rdev->state_lock);
if (ret)
goto done;
if (rdev->flags & TCMUR_DEV_FLAG_SHUTTING_DOWN) {
ret = 0;
goto done;
}
pthread_mutex_unlock(&rdev->state_lock);
/*
* There are no SCSI commands running but there may be
* async lock requests in progress that might be accessing
* the device.
*/
tcmu_cancel_lock_thread(dev);
/*
* Force a reacquisition of the lock when we have reopend the
* device, so it can update state. If we are being called from
* the lock code path then do not change state.
*/
pthread_mutex_lock(&rdev->state_lock);
if (rdev->lock_state != TCMUR_DEV_LOCK_LOCKING)
rdev->lock_state = TCMUR_DEV_LOCK_UNLOCKED;
pthread_mutex_unlock(&rdev->state_lock);
tcmu_dev_dbg(dev, "Closing device.\n");
rhandler->close(dev);
pthread_mutex_lock(&rdev->state_lock);
rdev->flags &= ~TCMUR_DEV_FLAG_IS_OPEN;
ret = -EIO;
while (ret != 0 && !(rdev->flags & TCMUR_DEV_FLAG_SHUTTING_DOWN)) {
pthread_mutex_unlock(&rdev->state_lock);
tcmu_dev_dbg(dev, "Opening device.\n");
ret = rhandler->open(dev);
pthread_mutex_lock(&rdev->state_lock);
if (!ret) {
rdev->flags |= TCMUR_DEV_FLAG_IS_OPEN;
}
}
done:
rdev->flags &= ~TCMUR_DEV_FLAG_IN_RECOVERY;
pthread_mutex_unlock(&rdev->state_lock);
return ret;
}
/*
* tcmu_reopen_dev - close and open device.
* @dev: device to reopen
*/
int tcmu_reopen_dev(struct tcmu_device *dev)
{
struct tcmur_device *rdev = tcmu_get_daemon_dev_private(dev);
pthread_mutex_lock(&rdev->state_lock);
if (rdev->flags & TCMUR_DEV_FLAG_IN_RECOVERY) {
pthread_mutex_unlock(&rdev->state_lock);
return -EBUSY;
}
rdev->flags |= TCMUR_DEV_FLAG_IN_RECOVERY;
pthread_mutex_unlock(&rdev->state_lock);
return __tcmu_reopen_dev(dev);
}
void tcmu_cancel_recovery(struct tcmu_device *dev)
{
struct tcmur_device *rdev = tcmu_get_daemon_dev_private(dev);
/*
* Only file and qcow can be canceled in their open/close calls, but
* they do not support recovery, so wait here for rbd/glfs type of
* handlers to fail/complete normally to avoid a segfault.
*/
tcmu_dev_dbg(dev, "Waiting on recovery thread\n");
pthread_mutex_lock(&rdev->state_lock);
while (rdev->flags & TCMUR_DEV_FLAG_IN_RECOVERY) {
pthread_mutex_unlock(&rdev->state_lock);
sleep(1);
pthread_mutex_lock(&rdev->state_lock);
}
pthread_mutex_unlock(&rdev->state_lock);
}
/**
* tcmu_notify_conn_lost - notify runner the device instace has lost its
* connection to its backend storage.
* @dev: device that has lost its connection
*
* Handlers should call this function when they detect they cannot reach their
* backend storage/medium/cache, so new commands will not be queued until
* the device has been reopened.
*/
void tcmu_notify_conn_lost(struct tcmu_device *dev)
{
struct tcmur_device *rdev = tcmu_get_daemon_dev_private(dev);
pthread_mutex_lock(&rdev->state_lock);
if (rdev->flags & TCMUR_DEV_FLAG_IN_RECOVERY)
goto unlock;
tcmu_dev_err(dev, "Handler connection lost (lock state %d)\n",
rdev->lock_state);
if (!tcmu_add_dev_to_recovery_list(dev))
rdev->flags |= TCMUR_DEV_FLAG_IN_RECOVERY;
unlock:
pthread_mutex_unlock(&rdev->state_lock);
}
/**
* tcmu_notify_lock_lost - notify runner the device instance has lost the lock
* @dev: device that has lost the lock
*
* Handlers should call this function when they detect they have lost
* the lock, so runner can re-acquire. It must be called before completing
* a command that had caused the failure.
*/
void tcmu_notify_lock_lost(struct tcmu_device *dev)
{
struct tcmur_device *rdev = tcmu_get_daemon_dev_private(dev);
pthread_mutex_lock(&rdev->state_lock);
tcmu_dev_err(dev, "Async lock drop. Old state %d\n", rdev->lock_state);
/*
* We could be getting stale IO completions. If we are trying to
* reaquire the lock do not change state.
*/
if (rdev->lock_state != TCMUR_DEV_LOCK_LOCKING)
rdev->lock_state = TCMUR_DEV_LOCK_UNLOCKED;
pthread_mutex_unlock(&rdev->state_lock);
}
int tcmu_cancel_lock_thread(struct tcmu_device *dev)
{
struct tcmur_device *rdev = tcmu_get_daemon_dev_private(dev);
void *join_retval;
int ret;
pthread_mutex_lock(&rdev->state_lock);
if (rdev->lock_state != TCMUR_DEV_LOCK_LOCKING) {
pthread_mutex_unlock(&rdev->state_lock);
return 0;
}
pthread_mutex_unlock(&rdev->state_lock);
/*
* It looks like lock calls are not cancelable, so
* we wait here to avoid crashes.
*/
tcmu_dev_dbg(dev, "Waiting on lock thread\n");
ret = pthread_join(rdev->lock_thread, &join_retval);
/*
* We may be called from the lock thread to reopen the device.
*/
if (ret != EDEADLK)
tcmu_dev_err(dev, "pthread_join failed with value %d\n", ret);
return ret;
}
int tcmu_acquire_dev_lock(struct tcmu_device *dev)
{
struct tcmur_handler *rhandler = tcmu_get_runner_handler(dev);
struct tcmur_device *rdev = tcmu_get_daemon_dev_private(dev);
int ret, retries = 0, new_state = TCMUR_DEV_LOCK_UNLOCKED;
tcmu_dev_dbg(dev, "Waiting for outstanding commands to complete\n");
if (aio_wait_for_empty_queue(rdev)) {
tcmu_dev_err(dev, "Not able to flush queue before taking lock.\n");
ret = TCMUR_LOCK_FAILED;
goto done;
}
retry:
tcmu_dev_dbg(dev, "lock call state %d retries %d\n",
rdev->lock_state, retries);
ret = rhandler->lock(dev);
switch (ret) {
case TCMUR_LOCK_BUSY:
new_state = TCMUR_DEV_LOCK_LOCKING;
break;
case TCMUR_LOCK_FAILED:
new_state = TCMUR_DEV_LOCK_UNLOCKED;
break;
case TCMUR_LOCK_SUCCESS:
new_state = TCMUR_DEV_LOCK_LOCKED;
break;
case TCMUR_LOCK_NOTCONN:
/*
* Try to reconnect to the backend device. If this
* fails then go into recovery, so the initaitor
* can drop down to another path.
*/
tcmu_dev_dbg(dev, "Try to reopen device.\n");
if (retries < 1 && !tcmu_reopen_dev(dev)) {
retries++;
goto retry;
}
tcmu_dev_dbg(dev, "Fail handler device connection.\n");
tcmu_notify_conn_lost(dev);
new_state = TCMUR_DEV_LOCK_UNLOCKED;
break;
}
done:
/* TODO: set UA based on bgly's patches */
pthread_mutex_lock(&rdev->state_lock);
rdev->lock_state = new_state;
tcmu_dev_dbg(dev, "lock call done. lock state %d\n", rdev->lock_state);
pthread_mutex_unlock(&rdev->state_lock);
return ret;
}