529 lines
14 KiB
C
529 lines
14 KiB
C
/*
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* (C) 2001 Clemson University and The University of Chicago
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* (C) 2011 Omnibond Systems
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*
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* Changes by Acxiom Corporation to implement generic service_operation()
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* function, Copyright Acxiom Corporation, 2005.
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*
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* See COPYING in top-level directory.
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*/
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/*
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* In-kernel waitqueue operations.
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*/
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#include "protocol.h"
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#include "pvfs2-kernel.h"
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#include "pvfs2-bufmap.h"
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/*
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* What we do in this function is to walk the list of operations that are
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* present in the request queue and mark them as purged.
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* NOTE: This is called from the device close after client-core has
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* guaranteed that no new operations could appear on the list since the
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* client-core is anyway going to exit.
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*/
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void purge_waiting_ops(void)
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{
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struct pvfs2_kernel_op_s *op;
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spin_lock(&pvfs2_request_list_lock);
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list_for_each_entry(op, &pvfs2_request_list, list) {
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"pvfs2-client-core: purging op tag %llu %s\n",
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llu(op->tag),
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get_opname_string(op));
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spin_lock(&op->lock);
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set_op_state_purged(op);
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spin_unlock(&op->lock);
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wake_up_interruptible(&op->waitq);
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}
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spin_unlock(&pvfs2_request_list_lock);
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}
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/*
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* submits a PVFS2 operation and waits for it to complete
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*
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* Note op->downcall.status will contain the status of the operation (in
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* errno format), whether provided by pvfs2-client or a result of failure to
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* service the operation. If the caller wishes to distinguish, then
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* op->state can be checked to see if it was serviced or not.
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*
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* Returns contents of op->downcall.status for convenience
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*/
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int service_operation(struct pvfs2_kernel_op_s *op,
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const char *op_name,
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int flags)
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{
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/* flags to modify behavior */
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sigset_t orig_sigset;
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int ret = 0;
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/* irqflags and wait_entry are only used IF the client-core aborts */
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unsigned long irqflags;
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DECLARE_WAITQUEUE(wait_entry, current);
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op->upcall.tgid = current->tgid;
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op->upcall.pid = current->pid;
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retry_servicing:
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op->downcall.status = 0;
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"pvfs2: service_operation: %s %p\n",
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op_name,
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op);
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"pvfs2: operation posted by process: %s, pid: %i\n",
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current->comm,
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current->pid);
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/* mask out signals if this operation is not to be interrupted */
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if (!(flags & PVFS2_OP_INTERRUPTIBLE))
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mask_blocked_signals(&orig_sigset);
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if (!(flags & PVFS2_OP_NO_SEMAPHORE)) {
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ret = mutex_lock_interruptible(&request_mutex);
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/*
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* check to see if we were interrupted while waiting for
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* semaphore
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*/
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if (ret < 0) {
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if (!(flags & PVFS2_OP_INTERRUPTIBLE))
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unmask_blocked_signals(&orig_sigset);
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op->downcall.status = ret;
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"pvfs2: service_operation interrupted.\n");
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return ret;
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}
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}
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"%s:About to call is_daemon_in_service().\n",
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__func__);
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if (is_daemon_in_service() < 0) {
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/*
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* By incrementing the per-operation attempt counter, we
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* directly go into the timeout logic while waiting for
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* the matching downcall to be read
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*/
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"%s:client core is NOT in service(%d).\n",
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__func__,
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is_daemon_in_service());
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op->attempts++;
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}
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/* queue up the operation */
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if (flags & PVFS2_OP_PRIORITY) {
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add_priority_op_to_request_list(op);
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} else {
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"%s:About to call add_op_to_request_list().\n",
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__func__);
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add_op_to_request_list(op);
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}
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if (!(flags & PVFS2_OP_NO_SEMAPHORE))
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mutex_unlock(&request_mutex);
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/*
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* If we are asked to service an asynchronous operation from
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* VFS perspective, we are done.
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*/
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if (flags & PVFS2_OP_ASYNC)
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return 0;
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if (flags & PVFS2_OP_CANCELLATION) {
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"%s:"
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"About to call wait_for_cancellation_downcall.\n",
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__func__);
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ret = wait_for_cancellation_downcall(op);
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} else {
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ret = wait_for_matching_downcall(op);
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}
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if (ret < 0) {
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/* failed to get matching downcall */
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if (ret == -ETIMEDOUT) {
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gossip_err("pvfs2: %s -- wait timed out; aborting attempt.\n",
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op_name);
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}
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op->downcall.status = ret;
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} else {
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/* got matching downcall; make sure status is in errno format */
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op->downcall.status =
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pvfs2_normalize_to_errno(op->downcall.status);
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ret = op->downcall.status;
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}
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if (!(flags & PVFS2_OP_INTERRUPTIBLE))
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unmask_blocked_signals(&orig_sigset);
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BUG_ON(ret != op->downcall.status);
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/* retry if operation has not been serviced and if requested */
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if (!op_state_serviced(op) && op->downcall.status == -EAGAIN) {
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"pvfs2: tag %llu (%s)"
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" -- operation to be retried (%d attempt)\n",
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llu(op->tag),
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op_name,
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op->attempts + 1);
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if (!op->uses_shared_memory)
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/*
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* this operation doesn't use the shared memory
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* system
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*/
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goto retry_servicing;
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/* op uses shared memory */
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if (get_bufmap_init() == 0) {
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/*
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* This operation uses the shared memory system AND
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* the system is not yet ready. This situation occurs
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* when the client-core is restarted AND there were
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* operations waiting to be processed or were already
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* in process.
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*/
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"uses_shared_memory is true.\n");
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"Client core in-service status(%d).\n",
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is_daemon_in_service());
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gossip_debug(GOSSIP_WAIT_DEBUG, "bufmap_init:%d.\n",
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get_bufmap_init());
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"operation's status is 0x%0x.\n",
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op->op_state);
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/*
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* let process sleep for a few seconds so shared
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* memory system can be initialized.
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*/
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spin_lock_irqsave(&op->lock, irqflags);
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add_wait_queue(&pvfs2_bufmap_init_waitq, &wait_entry);
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spin_unlock_irqrestore(&op->lock, irqflags);
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set_current_state(TASK_INTERRUPTIBLE);
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/*
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* Wait for pvfs_bufmap_initialize() to wake me up
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* within the allotted time.
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*/
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ret = schedule_timeout(MSECS_TO_JIFFIES
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(1000 * PVFS2_BUFMAP_WAIT_TIMEOUT_SECS));
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"Value returned from schedule_timeout:"
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"%d.\n",
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ret);
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"Is shared memory available? (%d).\n",
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get_bufmap_init());
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spin_lock_irqsave(&op->lock, irqflags);
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remove_wait_queue(&pvfs2_bufmap_init_waitq,
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&wait_entry);
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spin_unlock_irqrestore(&op->lock, irqflags);
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if (get_bufmap_init() == 0) {
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gossip_err("%s:The shared memory system has not started in %d seconds after the client core restarted. Aborting user's request(%s).\n",
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__func__,
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PVFS2_BUFMAP_WAIT_TIMEOUT_SECS,
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get_opname_string(op));
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return -EIO;
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}
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/*
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* Return to the calling function and re-populate a
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* shared memory buffer.
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*/
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return -EAGAIN;
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}
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}
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"pvfs2: service_operation %s returning: %d for %p.\n",
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op_name,
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ret,
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op);
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return ret;
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}
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void pvfs2_clean_up_interrupted_operation(struct pvfs2_kernel_op_s *op)
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{
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/*
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* handle interrupted cases depending on what state we were in when
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* the interruption is detected. there is a coarse grained lock
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* across the operation.
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*
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* NOTE: be sure not to reverse lock ordering by locking an op lock
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* while holding the request_list lock. Here, we first lock the op
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* and then lock the appropriate list.
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*/
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if (!op) {
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"%s: op is null, ignoring\n",
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__func__);
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return;
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}
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/*
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* one more sanity check, make sure it's in one of the possible states
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* or don't try to cancel it
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*/
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if (!(op_state_waiting(op) ||
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op_state_in_progress(op) ||
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op_state_serviced(op) ||
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op_state_purged(op))) {
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"%s: op %p not in a valid state (%0x), "
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"ignoring\n",
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__func__,
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op,
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op->op_state);
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return;
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}
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spin_lock(&op->lock);
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if (op_state_waiting(op)) {
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/*
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* upcall hasn't been read; remove op from upcall request
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* list.
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*/
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spin_unlock(&op->lock);
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remove_op_from_request_list(op);
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"Interrupted: Removed op %p from request_list\n",
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op);
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} else if (op_state_in_progress(op)) {
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/* op must be removed from the in progress htable */
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spin_unlock(&op->lock);
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spin_lock(&htable_ops_in_progress_lock);
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list_del(&op->list);
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spin_unlock(&htable_ops_in_progress_lock);
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"Interrupted: Removed op %p"
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" from htable_ops_in_progress\n",
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op);
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} else if (!op_state_serviced(op)) {
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spin_unlock(&op->lock);
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gossip_err("interrupted operation is in a weird state 0x%x\n",
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op->op_state);
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} else {
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/*
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* It is not intended for execution to flow here,
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* but having this unlock here makes sparse happy.
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*/
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gossip_err("%s: can't get here.\n", __func__);
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spin_unlock(&op->lock);
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}
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}
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/*
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* sleeps on waitqueue waiting for matching downcall.
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* if client-core finishes servicing, then we are good to go.
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* else if client-core exits, we get woken up here, and retry with a timeout
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*
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* Post when this call returns to the caller, the specified op will no
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* longer be on any list or htable.
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*
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* Returns 0 on success and -errno on failure
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* Errors are:
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* EAGAIN in case we want the caller to requeue and try again..
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* EINTR/EIO/ETIMEDOUT indicating we are done trying to service this
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* operation since client-core seems to be exiting too often
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* or if we were interrupted.
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*/
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int wait_for_matching_downcall(struct pvfs2_kernel_op_s *op)
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{
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int ret = -EINVAL;
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DECLARE_WAITQUEUE(wait_entry, current);
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spin_lock(&op->lock);
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add_wait_queue(&op->waitq, &wait_entry);
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spin_unlock(&op->lock);
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while (1) {
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set_current_state(TASK_INTERRUPTIBLE);
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spin_lock(&op->lock);
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if (op_state_serviced(op)) {
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spin_unlock(&op->lock);
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ret = 0;
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break;
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}
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spin_unlock(&op->lock);
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if (!signal_pending(current)) {
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/*
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* if this was our first attempt and client-core
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* has not purged our operation, we are happy to
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* simply wait
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*/
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spin_lock(&op->lock);
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if (op->attempts == 0 && !op_state_purged(op)) {
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spin_unlock(&op->lock);
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schedule();
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} else {
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spin_unlock(&op->lock);
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/*
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* subsequent attempts, we retry exactly once
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* with timeouts
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*/
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if (!schedule_timeout(MSECS_TO_JIFFIES
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(1000 * op_timeout_secs))) {
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"*** %s:"
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" operation timed out (tag"
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" %llu, %p, att %d)\n",
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__func__,
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llu(op->tag),
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op,
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op->attempts);
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ret = -ETIMEDOUT;
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pvfs2_clean_up_interrupted_operation
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(op);
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break;
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}
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}
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spin_lock(&op->lock);
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op->attempts++;
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/*
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* if the operation was purged in the meantime, it
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* is better to requeue it afresh but ensure that
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* we have not been purged repeatedly. This could
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* happen if client-core crashes when an op
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* is being serviced, so we requeue the op, client
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* core crashes again so we requeue the op, client
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* core starts, and so on...
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*/
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if (op_state_purged(op)) {
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ret = (op->attempts < PVFS2_PURGE_RETRY_COUNT) ?
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-EAGAIN :
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-EIO;
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spin_unlock(&op->lock);
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"*** %s:"
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" operation purged (tag "
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"%llu, %p, att %d)\n",
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__func__,
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llu(op->tag),
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op,
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op->attempts);
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pvfs2_clean_up_interrupted_operation(op);
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break;
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}
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spin_unlock(&op->lock);
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continue;
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}
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"*** %s:"
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" operation interrupted by a signal (tag "
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"%llu, op %p)\n",
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__func__,
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llu(op->tag),
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op);
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pvfs2_clean_up_interrupted_operation(op);
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ret = -EINTR;
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break;
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}
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set_current_state(TASK_RUNNING);
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spin_lock(&op->lock);
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remove_wait_queue(&op->waitq, &wait_entry);
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spin_unlock(&op->lock);
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return ret;
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}
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/*
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* similar to wait_for_matching_downcall(), but used in the special case
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* of I/O cancellations.
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*
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* Note we need a special wait function because if this is called we already
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* know that a signal is pending in current and need to service the
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* cancellation upcall anyway. the only way to exit this is to either
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* timeout or have the cancellation be serviced properly.
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*/
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int wait_for_cancellation_downcall(struct pvfs2_kernel_op_s *op)
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{
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int ret = -EINVAL;
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DECLARE_WAITQUEUE(wait_entry, current);
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spin_lock(&op->lock);
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add_wait_queue(&op->waitq, &wait_entry);
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spin_unlock(&op->lock);
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while (1) {
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set_current_state(TASK_INTERRUPTIBLE);
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spin_lock(&op->lock);
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if (op_state_serviced(op)) {
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"%s:op-state is SERVICED.\n",
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__func__);
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spin_unlock(&op->lock);
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ret = 0;
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break;
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}
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spin_unlock(&op->lock);
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if (signal_pending(current)) {
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"%s:operation interrupted by a signal (tag"
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" %llu, op %p)\n",
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__func__,
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llu(op->tag),
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op);
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pvfs2_clean_up_interrupted_operation(op);
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ret = -EINTR;
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break;
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}
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"%s:About to call schedule_timeout.\n",
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__func__);
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ret =
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schedule_timeout(MSECS_TO_JIFFIES(1000 * op_timeout_secs));
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"%s:Value returned from schedule_timeout(%d).\n",
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__func__,
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ret);
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if (!ret) {
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"%s:*** operation timed out: %p\n",
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__func__,
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op);
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pvfs2_clean_up_interrupted_operation(op);
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ret = -ETIMEDOUT;
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break;
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}
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"%s:Breaking out of loop, regardless of value returned by schedule_timeout.\n",
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__func__);
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ret = -ETIMEDOUT;
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break;
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}
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set_current_state(TASK_RUNNING);
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spin_lock(&op->lock);
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remove_wait_queue(&op->waitq, &wait_entry);
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spin_unlock(&op->lock);
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gossip_debug(GOSSIP_WAIT_DEBUG,
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"%s:returning ret(%d)\n",
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__func__,
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ret);
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|
|
return ret;
|
|
}
|