1 files changed, 373 insertions, 0 deletions
diff --git a/fs/orangefs/waitqueue.c b/fs/orangefs/waitqueue.c
new file mode 100644
index 000000000..beafc33d5
--- /dev/null
+++ b/fs/orangefs/waitqueue.c
@@ -0,0 +1,373 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * (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 *op,
+		long timeout,
+		int flags)
+			__acquires(op->lock);
+static void orangefs_clean_up_interrupted_operation(struct orangefs_kernel_op_s *op)
+	__releases(op->lock);
+
+/*
+ * 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, *tmp;
+
+	spin_lock(&orangefs_request_list_lock);
+	list_for_each_entry_safe(op, tmp, &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);
+	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)
+		__releases(op->lock)
+{
+	/*
+	 * 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,
+		int flags)
+			__acquires(op->lock)
+{
+	long n;
+	int writeback = flags & ORANGEFS_OP_WRITEBACK,
+	    interruptible = flags & ORANGEFS_OP_INTERRUPTIBLE;
+
+	/*
+	 * 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 (writeback)
+		n = wait_for_completion_io_timeout(&op->waitq, timeout);
+	else if (!writeback && interruptible)
+		n = wait_for_completion_interruptible_timeout(&op->waitq,
+								      timeout);
+	else /* !writeback && !interruptible but compiler complains */
+		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;
+}