Orangefs: kernel client part 5
Signed-off-by: Mike Marshall <hubcap@omnibond.com>
diff --git a/fs/orangefs/waitqueue.c b/fs/orangefs/waitqueue.c
new file mode 100644
index 0000000..9b32286
--- /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;
+}