fs/orangefs/waitqueue.c - arm/linux - Git at Google

 /*
  * (C) 2001 Clemson University and The University of Chicago
  * (C) 2011 Omnibond Systems
  *
  * Changes by Acxiom Corporation to implement generic service_operation()
  * function, Copyright Acxiom Corporation, 2005.
  *
  * See COPYING in top-level directory.
  */

 /*
  *  In-kernel waitqueue operations.
  */

 #include "protocol.h"
 #include "orangefs-kernel.h"
 #include "orangefs-bufmap.h"

 static int wait_for_matching_downcall(struct orangefs_kernel_op_s *, long, bool);
 static void orangefs_clean_up_interrupted_operation(struct orangefs_kernel_op_s *);

 /*
  * What we do in this function is to walk the list of operations that are
  * present in the request queue and mark them as purged.
  * NOTE: This is called from the device close after client-core has
  * guaranteed that no new operations could appear on the list since the
  * client-core is anyway going to exit.
  */
 void purge_waiting_ops(void)
 {
 	struct orangefs_kernel_op_s *op;

 	spin_lock(&orangefs_request_list_lock);
 	list_for_each_entry(op, &orangefs_request_list, list) {
 		gossip_debug(GOSSIP_WAIT_DEBUG,
 			     "pvfs2-client-core: purging op tag %llu %s\n",
 			     llu(op->tag),
 			     get_opname_string(op));
 		set_op_state_purged(op);
 		gossip_debug(GOSSIP_DEV_DEBUG,
 			     "%s: op:%s: op_state:%d: process:%s:\n",
 			     __func__,
 			     get_opname_string(op),
 			     op->op_state,
 			     current->comm);
 	}
 	spin_unlock(&orangefs_request_list_lock);
 }

 /*
  * submits a ORANGEFS operation and waits for it to complete
  *
  * Note op->downcall.status will contain the status of the operation (in
  * errno format), whether provided by pvfs2-client or a result of failure to
  * service the operation.  If the caller wishes to distinguish, then
  * op->state can be checked to see if it was serviced or not.
  *
  * Returns contents of op->downcall.status for convenience
  */
 int service_operation(struct orangefs_kernel_op_s *op,
 		      const char *op_name,
 		      int flags)
 {
 	long timeout = MAX_SCHEDULE_TIMEOUT;
 	int ret = 0;

 	DEFINE_WAIT(wait_entry);

 	op->upcall.tgid = current->tgid;
 	op->upcall.pid = current->pid;

 retry_servicing:
 	op->downcall.status = 0;
 	gossip_debug(GOSSIP_WAIT_DEBUG,
 		     "%s: %s op:%p: process:%s: pid:%d:\n",
 		     __func__,
 		     op_name,
 		     op,
 		     current->comm,
 		     current->pid);

 	/*
 	 * If ORANGEFS_OP_NO_MUTEX was set in flags, we need to avoid
 	 * acquiring the request_mutex because we're servicing a
 	 * high priority remount operation and the request_mutex is
 	 * already taken.
 	 */
 	if (!(flags & ORANGEFS_OP_NO_MUTEX)) {
 		if (flags & ORANGEFS_OP_INTERRUPTIBLE)
 			ret = mutex_lock_interruptible(&orangefs_request_mutex);
 		else
 			ret = mutex_lock_killable(&orangefs_request_mutex);
 		/*
 		 * check to see if we were interrupted while waiting for
 		 * mutex
 		 */
 		if (ret < 0) {
 			op->downcall.status = ret;
 			gossip_debug(GOSSIP_WAIT_DEBUG,
 				     "%s: service_operation interrupted.\n",
 				     __func__);
 			return ret;
 		}
 	}

 	/* queue up the operation */
 	spin_lock(&orangefs_request_list_lock);
 	spin_lock(&op->lock);
 	set_op_state_waiting(op);
 	gossip_debug(GOSSIP_DEV_DEBUG,
 		     "%s: op:%s: op_state:%d: process:%s:\n",
 		     __func__,
 		     get_opname_string(op),
 		     op->op_state,
 		     current->comm);
 	/* add high priority remount op to the front of the line. */
 	if (flags & ORANGEFS_OP_PRIORITY)
 		list_add(&op->list, &orangefs_request_list);
 	else
 		list_add_tail(&op->list, &orangefs_request_list);
 	spin_unlock(&op->lock);
 	wake_up_interruptible(&orangefs_request_list_waitq);
 	if (!__is_daemon_in_service()) {
 		gossip_debug(GOSSIP_WAIT_DEBUG,
 			     "%s:client core is NOT in service.\n",
 			     __func__);
 		/*
 		 * Don't wait for the userspace component to return if
 		 * the filesystem is being umounted anyway.
 		 */
 		if (op->upcall.type == ORANGEFS_VFS_OP_FS_UMOUNT)
 			timeout = 0;
 		else
 			timeout = op_timeout_secs * HZ;
 	}
 	spin_unlock(&orangefs_request_list_lock);

 	if (!(flags & ORANGEFS_OP_NO_MUTEX))
 		mutex_unlock(&orangefs_request_mutex);

 	ret = wait_for_matching_downcall(op, timeout,
 					 flags & ORANGEFS_OP_INTERRUPTIBLE);

 	gossip_debug(GOSSIP_WAIT_DEBUG,
 		     "%s: wait_for_matching_downcall returned %d for %p\n",
 		     __func__,
 		     ret,
 		     op);

 	/* got matching downcall; make sure status is in errno format */
 	if (!ret) {
 		spin_unlock(&op->lock);
 		op->downcall.status =
 		    orangefs_normalize_to_errno(op->downcall.status);
 		ret = op->downcall.status;
 		goto out;
 	}

 	/* failed to get matching downcall */
 	if (ret == -ETIMEDOUT) {
 		gossip_err("%s: %s -- wait timed out; aborting attempt.\n",
 			   __func__,
 			   op_name);
 	}

 	/*
 	 * remove a waiting op from the request list or
 	 * remove an in-progress op from the in-progress list.
 	 */
 	orangefs_clean_up_interrupted_operation(op);

 	op->downcall.status = ret;
 	/* retry if operation has not been serviced and if requested */
 	if (ret == -EAGAIN) {
 		op->attempts++;
 		timeout = op_timeout_secs * HZ;
 		gossip_debug(GOSSIP_WAIT_DEBUG,
 			     "orangefs: tag %llu (%s)"
 			     " -- operation to be retried (%d attempt)\n",
 			     llu(op->tag),
 			     op_name,
 			     op->attempts);

 		/*
 		 * io ops (ops that use the shared memory buffer) have
 		 * to be returned to their caller for a retry. Other ops
 		 * can just be recycled here.
 		 */
 		if (!op->uses_shared_memory)
 			goto retry_servicing;
 	}

 out:
 	gossip_debug(GOSSIP_WAIT_DEBUG,
 		     "%s: %s returning: %d for %p.\n",
 		     __func__,
 		     op_name,
 		     ret,
 		     op);
 	return ret;
 }

 /* This can get called on an I/O op if it had a bad service_operation. */
 bool orangefs_cancel_op_in_progress(struct orangefs_kernel_op_s *op)
 {
 	u64 tag = op->tag;
 	if (!op_state_in_progress(op))
 		return false;

 	op->slot_to_free = op->upcall.req.io.buf_index;
 	memset(&op->upcall, 0, sizeof(op->upcall));
 	memset(&op->downcall, 0, sizeof(op->downcall));
 	op->upcall.type = ORANGEFS_VFS_OP_CANCEL;
 	op->upcall.req.cancel.op_tag = tag;
 	op->downcall.type = ORANGEFS_VFS_OP_INVALID;
 	op->downcall.status = -1;
 	orangefs_new_tag(op);

 	spin_lock(&orangefs_request_list_lock);
 	/* orangefs_request_list_lock is enough of a barrier here */
 	if (!__is_daemon_in_service()) {
 		spin_unlock(&orangefs_request_list_lock);
 		return false;
 	}
 	spin_lock(&op->lock);
 	set_op_state_waiting(op);
 	gossip_debug(GOSSIP_DEV_DEBUG,
 		     "%s: op:%s: op_state:%d: process:%s:\n",
 		     __func__,
 		     get_opname_string(op),
 		     op->op_state,
 		     current->comm);
 	list_add(&op->list, &orangefs_request_list);
 	spin_unlock(&op->lock);
 	spin_unlock(&orangefs_request_list_lock);

 	gossip_debug(GOSSIP_WAIT_DEBUG,
 		     "Attempting ORANGEFS operation cancellation of tag %llu\n",
 		     llu(tag));
 	return true;
 }

 /*
  * Change an op to the "given up" state and remove it from its list.
  */
 static void
 	orangefs_clean_up_interrupted_operation(struct orangefs_kernel_op_s *op)
 {
 	/*
 	 * handle interrupted cases depending on what state we were in when
 	 * the interruption is detected.
 	 *
 	 * Called with op->lock held.
 	 */

 	/*
 	 * List manipulation code elsewhere will ignore ops that
 	 * have been given up upon.
 	 */
 	op->op_state |= OP_VFS_STATE_GIVEN_UP;

 	if (list_empty(&op->list)) {
 		/* caught copying to/from daemon */
 		BUG_ON(op_state_serviced(op));
 		spin_unlock(&op->lock);
 		wait_for_completion(&op->waitq);
 	} else if (op_state_waiting(op)) {
 		/*
 		 * upcall hasn't been read; remove op from upcall request
 		 * list.
 		 */
 		spin_unlock(&op->lock);
 		spin_lock(&orangefs_request_list_lock);
 		list_del_init(&op->list);
 		spin_unlock(&orangefs_request_list_lock);
 		gossip_debug(GOSSIP_WAIT_DEBUG,
 			     "Interrupted: Removed op %p from request_list\n",
 			     op);
 	} else if (op_state_in_progress(op)) {
 		/* op must be removed from the in progress htable */
 		spin_unlock(&op->lock);
 		spin_lock(&orangefs_htable_ops_in_progress_lock);
 		list_del_init(&op->list);
 		spin_unlock(&orangefs_htable_ops_in_progress_lock);
 		gossip_debug(GOSSIP_WAIT_DEBUG,
 			     "Interrupted: Removed op %p"
 			     " from htable_ops_in_progress\n",
 			     op);
 	} else {
 		spin_unlock(&op->lock);
 		gossip_err("interrupted operation is in a weird state 0x%x\n",
 			   op->op_state);
 	}
 	reinit_completion(&op->waitq);
 }

 /*
  * Sleeps on waitqueue waiting for matching downcall.
  * If client-core finishes servicing, then we are good to go.
  * else if client-core exits, we get woken up here, and retry with a timeout
  *
  * When this call returns to the caller, the specified op will no
  * longer be in either the in_progress hash table or on the request list.
  *
  * Returns 0 on success and -errno on failure
  * Errors are:
  * EAGAIN in case we want the caller to requeue and try again..
  * EINTR/EIO/ETIMEDOUT indicating we are done trying to service this
  * operation since client-core seems to be exiting too often
  * or if we were interrupted.
  *
  * Returns with op->lock taken.
  */
 static int wait_for_matching_downcall(struct orangefs_kernel_op_s *op,
 				      long timeout,
 				      bool interruptible)
 {
 	long n;

 	/*
 	 * There's a "schedule_timeout" inside of these wait
 	 * primitives, during which the op is out of the hands of the
 	 * user process that needs something done and is being
 	 * manipulated by the client-core process.
 	 */
 	if (interruptible)
 		n = wait_for_completion_interruptible_timeout(&op->waitq,
 							      timeout);
 	else
 		n = wait_for_completion_killable_timeout(&op->waitq, timeout);

 	spin_lock(&op->lock);

 	if (op_state_serviced(op))
 		return 0;

 	if (unlikely(n < 0)) {
 		gossip_debug(GOSSIP_WAIT_DEBUG,
 			     "%s: operation interrupted, tag %llu, %p\n",
 			     __func__,
 			     llu(op->tag),
 			     op);
 		return -EINTR;
 	}
 	if (op_state_purged(op)) {
 		gossip_debug(GOSSIP_WAIT_DEBUG,
 			     "%s: operation purged, tag %llu, %p, %d\n",
 			     __func__,
 			     llu(op->tag),
 			     op,
 			     op->attempts);
 		return (op->attempts < ORANGEFS_PURGE_RETRY_COUNT) ?
 			 -EAGAIN :
 			 -EIO;
 	}
 	/* must have timed out, then... */
 	gossip_debug(GOSSIP_WAIT_DEBUG,
 		     "%s: operation timed out, tag %llu, %p, %d)\n",
 		     __func__,
 		     llu(op->tag),
 		     op,
 		     op->attempts);
 	return -ETIMEDOUT;
 }
	/*
	* (C) 2001 Clemson University and The University of Chicago
	* (C) 2011 Omnibond Systems
	*
	* Changes by Acxiom Corporation to implement generic service_operation()
	* function, Copyright Acxiom Corporation, 2005.
	*
	* See COPYING in top-level directory.
	*/

	/*
	* In-kernel waitqueue operations.
	*/

	#include "protocol.h"
	#include "orangefs-kernel.h"
	#include "orangefs-bufmap.h"

	static int wait_for_matching_downcall(struct orangefs_kernel_op_s *, long, bool);
	static void orangefs_clean_up_interrupted_operation(struct orangefs_kernel_op_s *);

	/*
	* What we do in this function is to walk the list of operations that are
	* present in the request queue and mark them as purged.
	* NOTE: This is called from the device close after client-core has
	* guaranteed that no new operations could appear on the list since the
	* client-core is anyway going to exit.
	*/
	void purge_waiting_ops(void)
	{
	struct orangefs_kernel_op_s *op;

	spin_lock(&orangefs_request_list_lock);
	list_for_each_entry(op, &orangefs_request_list, list) {
	gossip_debug(GOSSIP_WAIT_DEBUG,
	"pvfs2-client-core: purging op tag %llu %s\n",
	llu(op->tag),
	get_opname_string(op));
	set_op_state_purged(op);
	gossip_debug(GOSSIP_DEV_DEBUG,
	"%s: op:%s: op_state:%d: process:%s:\n",
	__func__,
	get_opname_string(op),
	op->op_state,
	current->comm);
	}
	spin_unlock(&orangefs_request_list_lock);
	}

	/*
	* submits a ORANGEFS operation and waits for it to complete
	*
	* Note op->downcall.status will contain the status of the operation (in
	* errno format), whether provided by pvfs2-client or a result of failure to
	* service the operation. If the caller wishes to distinguish, then
	* op->state can be checked to see if it was serviced or not.
	*
	* Returns contents of op->downcall.status for convenience
	*/
	int service_operation(struct orangefs_kernel_op_s *op,
	const char *op_name,
	int flags)
	{
	long timeout = MAX_SCHEDULE_TIMEOUT;
	int ret = 0;

	DEFINE_WAIT(wait_entry);

	op->upcall.tgid = current->tgid;
	op->upcall.pid = current->pid;

	retry_servicing:
	op->downcall.status = 0;
	gossip_debug(GOSSIP_WAIT_DEBUG,
	"%s: %s op:%p: process:%s: pid:%d:\n",
	__func__,
	op_name,
	op,
	current->comm,
	current->pid);

	/*
	* If ORANGEFS_OP_NO_MUTEX was set in flags, we need to avoid
	* acquiring the request_mutex because we're servicing a
	* high priority remount operation and the request_mutex is
	* already taken.
	*/
	if (!(flags & ORANGEFS_OP_NO_MUTEX)) {
	if (flags & ORANGEFS_OP_INTERRUPTIBLE)
	ret = mutex_lock_interruptible(&orangefs_request_mutex);
	else
	ret = mutex_lock_killable(&orangefs_request_mutex);
	/*
	* check to see if we were interrupted while waiting for
	* mutex
	*/
	if (ret < 0) {
	op->downcall.status = ret;
	gossip_debug(GOSSIP_WAIT_DEBUG,
	"%s: service_operation interrupted.\n",
	__func__);
	return ret;
	}
	}

	/* queue up the operation */
	spin_lock(&orangefs_request_list_lock);
	spin_lock(&op->lock);
	set_op_state_waiting(op);
	gossip_debug(GOSSIP_DEV_DEBUG,
	"%s: op:%s: op_state:%d: process:%s:\n",
	__func__,
	get_opname_string(op),
	op->op_state,
	current->comm);
	/* add high priority remount op to the front of the line. */
	if (flags & ORANGEFS_OP_PRIORITY)
	list_add(&op->list, &orangefs_request_list);
	else
	list_add_tail(&op->list, &orangefs_request_list);
	spin_unlock(&op->lock);
	wake_up_interruptible(&orangefs_request_list_waitq);
	if (!__is_daemon_in_service()) {
	gossip_debug(GOSSIP_WAIT_DEBUG,
	"%s:client core is NOT in service.\n",
	__func__);
	/*
	* Don't wait for the userspace component to return if
	* the filesystem is being umounted anyway.
	*/
	if (op->upcall.type == ORANGEFS_VFS_OP_FS_UMOUNT)
	timeout = 0;
	else
	timeout = op_timeout_secs * HZ;
	}
	spin_unlock(&orangefs_request_list_lock);

	if (!(flags & ORANGEFS_OP_NO_MUTEX))
	mutex_unlock(&orangefs_request_mutex);

	ret = wait_for_matching_downcall(op, timeout,
	flags & ORANGEFS_OP_INTERRUPTIBLE);

	gossip_debug(GOSSIP_WAIT_DEBUG,
	"%s: wait_for_matching_downcall returned %d for %p\n",
	__func__,
	ret,
	op);

	/* got matching downcall; make sure status is in errno format */
	if (!ret) {
	spin_unlock(&op->lock);
	op->downcall.status =
	orangefs_normalize_to_errno(op->downcall.status);
	ret = op->downcall.status;
	goto out;
	}

	/* failed to get matching downcall */
	if (ret == -ETIMEDOUT) {
	gossip_err("%s: %s -- wait timed out; aborting attempt.\n",
	__func__,
	op_name);
	}

	/*
	* remove a waiting op from the request list or
	* remove an in-progress op from the in-progress list.
	*/
	orangefs_clean_up_interrupted_operation(op);

	op->downcall.status = ret;
	/* retry if operation has not been serviced and if requested */
	if (ret == -EAGAIN) {
	op->attempts++;
	timeout = op_timeout_secs * HZ;
	gossip_debug(GOSSIP_WAIT_DEBUG,
	"orangefs: tag %llu (%s)"
	" -- operation to be retried (%d attempt)\n",
	llu(op->tag),
	op_name,
	op->attempts);

	/*
	* io ops (ops that use the shared memory buffer) have
	* to be returned to their caller for a retry. Other ops
	* can just be recycled here.
	*/
	if (!op->uses_shared_memory)
	goto retry_servicing;
	}

	out:
	gossip_debug(GOSSIP_WAIT_DEBUG,
	"%s: %s returning: %d for %p.\n",
	__func__,
	op_name,
	ret,
	op);
	return ret;
	}

	/* This can get called on an I/O op if it had a bad service_operation. */
	bool orangefs_cancel_op_in_progress(struct orangefs_kernel_op_s *op)
	{
	u64 tag = op->tag;
	if (!op_state_in_progress(op))
	return false;

	op->slot_to_free = op->upcall.req.io.buf_index;
	memset(&op->upcall, 0, sizeof(op->upcall));
	memset(&op->downcall, 0, sizeof(op->downcall));
	op->upcall.type = ORANGEFS_VFS_OP_CANCEL;
	op->upcall.req.cancel.op_tag = tag;
	op->downcall.type = ORANGEFS_VFS_OP_INVALID;
	op->downcall.status = -1;
	orangefs_new_tag(op);

	spin_lock(&orangefs_request_list_lock);
	/* orangefs_request_list_lock is enough of a barrier here */
	if (!__is_daemon_in_service()) {
	spin_unlock(&orangefs_request_list_lock);
	return false;
	}
	spin_lock(&op->lock);
	set_op_state_waiting(op);
	gossip_debug(GOSSIP_DEV_DEBUG,
	"%s: op:%s: op_state:%d: process:%s:\n",
	__func__,
	get_opname_string(op),
	op->op_state,
	current->comm);
	list_add(&op->list, &orangefs_request_list);
	spin_unlock(&op->lock);
	spin_unlock(&orangefs_request_list_lock);

	gossip_debug(GOSSIP_WAIT_DEBUG,
	"Attempting ORANGEFS operation cancellation of tag %llu\n",
	llu(tag));
	return true;
	}

	/*
	* Change an op to the "given up" state and remove it from its list.
	*/
	static void
	orangefs_clean_up_interrupted_operation(struct orangefs_kernel_op_s *op)
	{
	/*
	* handle interrupted cases depending on what state we were in when
	* the interruption is detected.
	*
	* Called with op->lock held.
	*/

	/*
	* List manipulation code elsewhere will ignore ops that
	* have been given up upon.
	*/
	op->op_state \|= OP_VFS_STATE_GIVEN_UP;

	if (list_empty(&op->list)) {
	/* caught copying to/from daemon */
	BUG_ON(op_state_serviced(op));
	spin_unlock(&op->lock);
	wait_for_completion(&op->waitq);
	} else if (op_state_waiting(op)) {
	/*
	* upcall hasn't been read; remove op from upcall request
	* list.
	*/
	spin_unlock(&op->lock);
	spin_lock(&orangefs_request_list_lock);
	list_del_init(&op->list);
	spin_unlock(&orangefs_request_list_lock);
	gossip_debug(GOSSIP_WAIT_DEBUG,
	"Interrupted: Removed op %p from request_list\n",
	op);
	} else if (op_state_in_progress(op)) {
	/* op must be removed from the in progress htable */
	spin_unlock(&op->lock);
	spin_lock(&orangefs_htable_ops_in_progress_lock);
	list_del_init(&op->list);
	spin_unlock(&orangefs_htable_ops_in_progress_lock);
	gossip_debug(GOSSIP_WAIT_DEBUG,
	"Interrupted: Removed op %p"
	" from htable_ops_in_progress\n",
	op);
	} else {
	spin_unlock(&op->lock);
	gossip_err("interrupted operation is in a weird state 0x%x\n",
	op->op_state);
	}
	reinit_completion(&op->waitq);
	}

	/*
	* Sleeps on waitqueue waiting for matching downcall.
	* If client-core finishes servicing, then we are good to go.
	* else if client-core exits, we get woken up here, and retry with a timeout
	*
	* When this call returns to the caller, the specified op will no
	* longer be in either the in_progress hash table or on the request list.
	*
	* Returns 0 on success and -errno on failure
	* Errors are:
	* EAGAIN in case we want the caller to requeue and try again..
	* EINTR/EIO/ETIMEDOUT indicating we are done trying to service this
	* operation since client-core seems to be exiting too often
	* or if we were interrupted.
	*
	* Returns with op->lock taken.
	*/
	static int wait_for_matching_downcall(struct orangefs_kernel_op_s *op,
	long timeout,
	bool interruptible)
	{
	long n;

	/*
	* There's a "schedule_timeout" inside of these wait
	* primitives, during which the op is out of the hands of the
	* user process that needs something done and is being
	* manipulated by the client-core process.
	*/
	if (interruptible)
	n = wait_for_completion_interruptible_timeout(&op->waitq,
	timeout);
	else
	n = wait_for_completion_killable_timeout(&op->waitq, timeout);

	spin_lock(&op->lock);

	if (op_state_serviced(op))
	return 0;

	if (unlikely(n < 0)) {
	gossip_debug(GOSSIP_WAIT_DEBUG,
	"%s: operation interrupted, tag %llu, %p\n",
	__func__,
	llu(op->tag),
	op);
	return -EINTR;
	}
	if (op_state_purged(op)) {
	gossip_debug(GOSSIP_WAIT_DEBUG,
	"%s: operation purged, tag %llu, %p, %d\n",
	__func__,
	llu(op->tag),
	op,
	op->attempts);
	return (op->attempts < ORANGEFS_PURGE_RETRY_COUNT) ?
	-EAGAIN :
	-EIO;
	}
	/* must have timed out, then... */
	gossip_debug(GOSSIP_WAIT_DEBUG,
	"%s: operation timed out, tag %llu, %p, %d)\n",
	__func__,
	llu(op->tag),
	op,
	op->attempts);
	return -ETIMEDOUT;
	}