Orangefs: kernel client part 5

Signed-off-by: Mike Marshall <hubcap@omnibond.com>

1 files changed, 522 insertions, 0 deletions

diff --git a/fs/orangefs/waitqueue.c b/fs/orangefs/waitqueue.c
new file mode 100644
index 000000000000..9b32286a7dc4
--- /dev/null
+++ b/fs/orangefs/waitqueue.c
@@ -0,0 +1,522 @@
+/*
+ * (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 "pvfs2-kernel.h"
+#include "pvfs2-bufmap.h"
+
+/*
+ * 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 pvfs2_kernel_op_s *op;
+
+	spin_lock(&pvfs2_request_list_lock);
+	list_for_each_entry(op, &pvfs2_request_list, list) {
+		gossip_debug(GOSSIP_WAIT_DEBUG,
+			     "pvfs2-client-core: purging op tag %llu %s\n",
+			     llu(op->tag),
+			     get_opname_string(op));
+		spin_lock(&op->lock);
+		set_op_state_purged(op);
+		spin_unlock(&op->lock);
+		wake_up_interruptible(&op->waitq);
+	}
+	spin_unlock(&pvfs2_request_list_lock);
+}
+
+/*
+ * submits a PVFS2 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 pvfs2_kernel_op_s *op,
+		      const char *op_name,
+		      int flags)
+{
+	/* flags to modify behavior */
+	sigset_t orig_sigset;
+	int ret = 0;
+
+	/* irqflags and wait_entry are only used IF the client-core aborts */
+	unsigned long irqflags;
+
+	DECLARE_WAITQUEUE(wait_entry, current);
+
+	op->upcall.tgid = current->tgid;
+	op->upcall.pid = current->pid;
+
+retry_servicing:
+	op->downcall.status = 0;
+	gossip_debug(GOSSIP_WAIT_DEBUG,
+		     "pvfs2: service_operation: %s %p\n",
+		     op_name,
+		     op);
+	gossip_debug(GOSSIP_WAIT_DEBUG,
+		     "pvfs2: operation posted by process: %s, pid: %i\n",
+		     current->comm,
+		     current->pid);
+
+	/* mask out signals if this operation is not to be interrupted */
+	if (!(flags & PVFS2_OP_INTERRUPTIBLE))
+		mask_blocked_signals(&orig_sigset);
+
+	if (!(flags & PVFS2_OP_NO_SEMAPHORE)) {
+		ret = mutex_lock_interruptible(&request_mutex);
+		/*
+		 * check to see if we were interrupted while waiting for
+		 * semaphore
+		 */
+		if (ret < 0) {
+			if (!(flags & PVFS2_OP_INTERRUPTIBLE))
+				unmask_blocked_signals(&orig_sigset);
+			op->downcall.status = ret;
+			gossip_debug(GOSSIP_WAIT_DEBUG,
+				     "pvfs2: service_operation interrupted.\n");
+			return ret;
+		}
+	}
+
+	gossip_debug(GOSSIP_WAIT_DEBUG,
+		     "%s:About to call is_daemon_in_service().\n",
+		     __func__);
+
+	if (is_daemon_in_service() < 0) {
+		/*
+		 * By incrementing the per-operation attempt counter, we
+		 * directly go into the timeout logic while waiting for
+		 * the matching downcall to be read
+		 */
+		gossip_debug(GOSSIP_WAIT_DEBUG,
+			     "%s:client core is NOT in service(%d).\n",
+			     __func__,
+			     is_daemon_in_service());
+		op->attempts++;
+	}
+
+	/* queue up the operation */
+	if (flags & PVFS2_OP_PRIORITY) {
+		add_priority_op_to_request_list(op);
+	} else {
+		gossip_debug(GOSSIP_WAIT_DEBUG,
+			     "%s:About to call add_op_to_request_list().\n",
+			     __func__);
+		add_op_to_request_list(op);
+	}
+
+	if (!(flags & PVFS2_OP_NO_SEMAPHORE))
+		mutex_unlock(&request_mutex);
+
+	/*
+	 * If we are asked to service an asynchronous operation from
+	 * VFS perspective, we are done.
+	 */
+	if (flags & PVFS2_OP_ASYNC)
+		return 0;
+
+	if (flags & PVFS2_OP_CANCELLATION) {
+		gossip_debug(GOSSIP_WAIT_DEBUG,
+			     "%s:"
+			     "About to call wait_for_cancellation_downcall.\n",
+			     __func__);
+		ret = wait_for_cancellation_downcall(op);
+	} else {
+		ret = wait_for_matching_downcall(op);
+	}
+
+	if (ret < 0) {
+		/* failed to get matching downcall */
+		if (ret == -ETIMEDOUT) {
+			gossip_err("pvfs2: %s -- wait timed out; aborting attempt.\n",
+				   op_name);
+		}
+		op->downcall.status = ret;
+	} else {
+		/* got matching downcall; make sure status is in errno format */
+		op->downcall.status =
+		    pvfs2_normalize_to_errno(op->downcall.status);
+		ret = op->downcall.status;
+	}
+
+	if (!(flags & PVFS2_OP_INTERRUPTIBLE))
+		unmask_blocked_signals(&orig_sigset);
+
+	BUG_ON(ret != op->downcall.status);
+	/* retry if operation has not been serviced and if requested */
+	if (!op_state_serviced(op) && op->downcall.status == -EAGAIN) {
+		gossip_debug(GOSSIP_WAIT_DEBUG,
+			     "pvfs2: tag %llu (%s)"
+			     " -- operation to be retried (%d attempt)\n",
+			     llu(op->tag),
+			     op_name,
+			     op->attempts + 1);
+
+		if (!op->uses_shared_memory)
+			/*
+			 * this operation doesn't use the shared memory
+			 * system
+			 */
+			goto retry_servicing;
+
+		/* op uses shared memory */
+		if (get_bufmap_init() == 0) {
+			/*
+			 * This operation uses the shared memory system AND
+			 * the system is not yet ready. This situation occurs
+			 * when the client-core is restarted AND there were
+			 * operations waiting to be processed or were already
+			 * in process.
+			 */
+			gossip_debug(GOSSIP_WAIT_DEBUG,
+				     "uses_shared_memory is true.\n");
+			gossip_debug(GOSSIP_WAIT_DEBUG,
+				     "Client core in-service status(%d).\n",
+				     is_daemon_in_service());
+			gossip_debug(GOSSIP_WAIT_DEBUG, "bufmap_init:%d.\n",
+				     get_bufmap_init());
+			gossip_debug(GOSSIP_WAIT_DEBUG,
+				     "operation's status is 0x%0x.\n",
+				     op->op_state);
+
+			/*
+			 * let process sleep for a few seconds so shared
+			 * memory system can be initialized.
+			 */
+			spin_lock_irqsave(&op->lock, irqflags);
+			add_wait_queue(&pvfs2_bufmap_init_waitq, &wait_entry);
+			spin_unlock_irqrestore(&op->lock, irqflags);
+
+			set_current_state(TASK_INTERRUPTIBLE);
+
+			/*
+			 * Wait for pvfs_bufmap_initialize() to wake me up
+			 * within the allotted time.
+			 */
+			ret = schedule_timeout(MSECS_TO_JIFFIES
+				(1000 * PVFS2_BUFMAP_WAIT_TIMEOUT_SECS));
+
+			gossip_debug(GOSSIP_WAIT_DEBUG,
+				     "Value returned from schedule_timeout:"
+				     "%d.\n",
+				     ret);
+			gossip_debug(GOSSIP_WAIT_DEBUG,
+				     "Is shared memory available? (%d).\n",
+				     get_bufmap_init());
+
+			spin_lock_irqsave(&op->lock, irqflags);
+			remove_wait_queue(&pvfs2_bufmap_init_waitq,
+					  &wait_entry);
+			spin_unlock_irqrestore(&op->lock, irqflags);
+
+			if (get_bufmap_init() == 0) {
+				gossip_err("%s:The shared memory system has not started in %d seconds after the client core restarted.  Aborting user's request(%s).\n",
+					   __func__,
+					   PVFS2_BUFMAP_WAIT_TIMEOUT_SECS,
+					   get_opname_string(op));
+				return -EIO;
+			}
+
+			/*
+			 * Return to the calling function and re-populate a
+			 * shared memory buffer.
+			 */
+			return -EAGAIN;
+		}
+	}
+
+	gossip_debug(GOSSIP_WAIT_DEBUG,
+		     "pvfs2: service_operation %s returning: %d for %p.\n",
+		     op_name,
+		     ret,
+		     op);
+	return ret;
+}
+
+void pvfs2_clean_up_interrupted_operation(struct pvfs2_kernel_op_s *op)
+{
+	/*
+	 * handle interrupted cases depending on what state we were in when
+	 * the interruption is detected.  there is a coarse grained lock
+	 * across the operation.
+	 *
+	 * NOTE: be sure not to reverse lock ordering by locking an op lock
+	 * while holding the request_list lock.  Here, we first lock the op
+	 * and then lock the appropriate list.
+	 */
+	if (!op) {
+		gossip_debug(GOSSIP_WAIT_DEBUG,
+			    "%s: op is null, ignoring\n",
+			     __func__);
+		return;
+	}
+
+	/*
+	 * one more sanity check, make sure it's in one of the possible states
+	 * or don't try to cancel it
+	 */
+	if (!(op_state_waiting(op) ||
+	      op_state_in_progress(op) ||
+	      op_state_serviced(op) ||
+	      op_state_purged(op))) {
+		gossip_debug(GOSSIP_WAIT_DEBUG,
+			     "%s: op %p not in a valid state (%0x), "
+			     "ignoring\n",
+			     __func__,
+			     op,
+			     op->op_state);
+		return;
+	}
+
+	spin_lock(&op->lock);
+
+	if (op_state_waiting(op)) {
+		/*
+		 * upcall hasn't been read; remove op from upcall request
+		 * list.
+		 */
+		spin_unlock(&op->lock);
+		remove_op_from_request_list(op);
+		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(&htable_ops_in_progress_lock);
+		list_del(&op->list);
+		spin_unlock(&htable_ops_in_progress_lock);
+		gossip_debug(GOSSIP_WAIT_DEBUG,
+			     "Interrupted: Removed op %p"
+			     " from htable_ops_in_progress\n",
+			     op);
+	} else if (!op_state_serviced(op)) {
+		spin_unlock(&op->lock);
+		gossip_err("interrupted operation is in a weird state 0x%x\n",
+			   op->op_state);
+	}
+}
+
+/*
+ * 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
+ *
+ * Post when this call returns to the caller, the specified op will no
+ * longer be on any list or htable.
+ *
+ * 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.
+ */
+int wait_for_matching_downcall(struct pvfs2_kernel_op_s *op)
+{
+	int ret = -EINVAL;
+	DECLARE_WAITQUEUE(wait_entry, current);
+
+	spin_lock(&op->lock);
+	add_wait_queue(&op->waitq, &wait_entry);
+	spin_unlock(&op->lock);
+
+	while (1) {
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		spin_lock(&op->lock);
+		if (op_state_serviced(op)) {
+			spin_unlock(&op->lock);
+			ret = 0;
+			break;
+		}
+		spin_unlock(&op->lock);
+
+		if (!signal_pending(current)) {
+			/*
+			 * if this was our first attempt and client-core
+			 * has not purged our operation, we are happy to
+			 * simply wait
+			 */
+			spin_lock(&op->lock);
+			if (op->attempts == 0 && !op_state_purged(op)) {
+				spin_unlock(&op->lock);
+				schedule();
+			} else {
+				spin_unlock(&op->lock);
+				/*
+				 * subsequent attempts, we retry exactly once
+				 * with timeouts
+				 */
+				if (!schedule_timeout(MSECS_TO_JIFFIES
+				      (1000 * op_timeout_secs))) {
+					gossip_debug(GOSSIP_WAIT_DEBUG,
+						     "*** %s:"
+						     " operation timed out (tag"
+						     " %llu, %p, att %d)\n",
+						     __func__,
+						     llu(op->tag),
+						     op,
+						     op->attempts);
+					ret = -ETIMEDOUT;
+					pvfs2_clean_up_interrupted_operation
+					    (op);
+					break;
+				}
+			}
+			spin_lock(&op->lock);
+			op->attempts++;
+			/*
+			 * if the operation was purged in the meantime, it
+			 * is better to requeue it afresh but ensure that
+			 * we have not been purged repeatedly. This could
+			 * happen if client-core crashes when an op
+			 * is being serviced, so we requeue the op, client
+			 * core crashes again so we requeue the op, client
+			 * core starts, and so on...
+			 */
+			if (op_state_purged(op)) {
+				ret = (op->attempts < PVFS2_PURGE_RETRY_COUNT) ?
+					 -EAGAIN :
+					 -EIO;
+				spin_unlock(&op->lock);
+				gossip_debug(GOSSIP_WAIT_DEBUG,
+					     "*** %s:"
+					     " operation purged (tag "
+					     "%llu, %p, att %d)\n",
+					     __func__,
+					     llu(op->tag),
+					     op,
+					     op->attempts);
+				pvfs2_clean_up_interrupted_operation(op);
+				break;
+			}
+			spin_unlock(&op->lock);
+			continue;
+		}
+
+		gossip_debug(GOSSIP_WAIT_DEBUG,
+			     "*** %s:"
+			     " operation interrupted by a signal (tag "
+			     "%llu, op %p)\n",
+			     __func__,
+			     llu(op->tag),
+			     op);
+		pvfs2_clean_up_interrupted_operation(op);
+		ret = -EINTR;
+		break;
+	}
+
+	set_current_state(TASK_RUNNING);
+
+	spin_lock(&op->lock);
+	remove_wait_queue(&op->waitq, &wait_entry);
+	spin_unlock(&op->lock);
+
+	return ret;
+}
+
+/*
+ * similar to wait_for_matching_downcall(), but used in the special case
+ * of I/O cancellations.
+ *
+ * Note we need a special wait function because if this is called we already
+ *      know that a signal is pending in current and need to service the
+ *      cancellation upcall anyway.  the only way to exit this is to either
+ *      timeout or have the cancellation be serviced properly.
+ */
+int wait_for_cancellation_downcall(struct pvfs2_kernel_op_s *op)
+{
+	int ret = -EINVAL;
+	DECLARE_WAITQUEUE(wait_entry, current);
+
+	spin_lock(&op->lock);
+	add_wait_queue(&op->waitq, &wait_entry);
+	spin_unlock(&op->lock);
+
+	while (1) {
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		spin_lock(&op->lock);
+		if (op_state_serviced(op)) {
+			gossip_debug(GOSSIP_WAIT_DEBUG,
+				     "%s:op-state is SERVICED.\n",
+				     __func__);
+			spin_unlock(&op->lock);
+			ret = 0;
+			break;
+		}
+		spin_unlock(&op->lock);
+
+		if (signal_pending(current)) {
+			gossip_debug(GOSSIP_WAIT_DEBUG,
+				     "%s:operation interrupted by a signal (tag"
+				     " %llu, op %p)\n",
+				     __func__,
+				     llu(op->tag),
+				     op);
+			pvfs2_clean_up_interrupted_operation(op);
+			ret = -EINTR;
+			break;
+		}
+
+		gossip_debug(GOSSIP_WAIT_DEBUG,
+			     "%s:About to call schedule_timeout.\n",
+			     __func__);
+		ret =
+		    schedule_timeout(MSECS_TO_JIFFIES(1000 * op_timeout_secs));
+
+		gossip_debug(GOSSIP_WAIT_DEBUG,
+			     "%s:Value returned from schedule_timeout(%d).\n",
+			     __func__,
+			     ret);
+		if (!ret) {
+			gossip_debug(GOSSIP_WAIT_DEBUG,
+				     "%s:*** operation timed out: %p\n",
+				     __func__,
+				     op);
+			pvfs2_clean_up_interrupted_operation(op);
+			ret = -ETIMEDOUT;
+			break;
+		}
+
+		gossip_debug(GOSSIP_WAIT_DEBUG,
+			     "%s:Breaking out of loop, regardless of value returned by schedule_timeout.\n",
+			     __func__);
+		ret = -ETIMEDOUT;
+		break;
+	}
+
+	set_current_state(TASK_RUNNING);
+
+	spin_lock(&op->lock);
+	remove_wait_queue(&op->waitq, &wait_entry);
+	spin_unlock(&op->lock);
+
+	gossip_debug(GOSSIP_WAIT_DEBUG,
+		     "%s:returning ret(%d)\n",
+		     __func__,
+		     ret);
+
+	return ret;
+}