[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / fscache / operation.c

/* FS-Cache worker operation management routines
 *
 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 * See Documentation/filesystems/caching/operations.txt
 */

#define FSCACHE_DEBUG_LEVEL OPERATION
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include "internal.h"

atomic_t fscache_op_debug_id;
EXPORT_SYMBOL(fscache_op_debug_id);

/**
 * fscache_enqueue_operation - Enqueue an operation for processing
 * @op: The operation to enqueue
 *
 * Enqueue an operation for processing by the FS-Cache thread pool.
 *
 * This will get its own ref on the object.
 */
void fscache_enqueue_operation(struct fscache_operation *op)
{
	_enter("{OBJ%x OP%x,%u}",
	       op->object->debug_id, op->debug_id, atomic_read(&op->usage));

	ASSERT(list_empty(&op->pend_link));
	ASSERT(op->processor != NULL);
	ASSERTCMP(op->object->state, >=, FSCACHE_OBJECT_AVAILABLE);
	ASSERTCMP(atomic_read(&op->usage), >, 0);
	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_IN_PROGRESS);

	fscache_stat(&fscache_n_op_enqueue);
	switch (op->flags & FSCACHE_OP_TYPE) {
	case FSCACHE_OP_ASYNC:
		_debug("queue async");
		atomic_inc(&op->usage);
		if (!queue_work(fscache_op_wq, &op->work))
			fscache_put_operation(op);
		break;
	case FSCACHE_OP_MYTHREAD:
		_debug("queue for caller's attention");
		break;
	default:
		printk(KERN_ERR "FS-Cache: Unexpected op type %lx",
		       op->flags);
		BUG();
		break;
	}
}
EXPORT_SYMBOL(fscache_enqueue_operation);

/*
 * start an op running
 */
static void fscache_run_op(struct fscache_object *object,
			   struct fscache_operation *op)
{
	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_PENDING);

	op->state = FSCACHE_OP_ST_IN_PROGRESS;
	object->n_in_progress++;
	if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
		wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
	if (op->processor)
		fscache_enqueue_operation(op);
	fscache_stat(&fscache_n_op_run);
}

/*
 * submit an exclusive operation for an object
 * - other ops are excluded from running simultaneously with this one
 * - this gets any extra refs it needs on an op
 */
int fscache_submit_exclusive_op(struct fscache_object *object,
				struct fscache_operation *op)
{
	int ret;

	_enter("{OBJ%x OP%x},", object->debug_id, op->debug_id);

	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_INITIALISED);
	ASSERTCMP(atomic_read(&op->usage), >, 0);

	spin_lock(&object->lock);
	ASSERTCMP(object->n_ops, >=, object->n_in_progress);
	ASSERTCMP(object->n_ops, >=, object->n_exclusive);
	ASSERT(list_empty(&op->pend_link));

	op->state = FSCACHE_OP_ST_PENDING;
	if (fscache_object_is_active(object)) {
		op->object = object;
		object->n_ops++;
		object->n_exclusive++;	/* reads and writes must wait */

		if (object->n_in_progress > 0) {
			atomic_inc(&op->usage);
			list_add_tail(&op->pend_link, &object->pending_ops);
			fscache_stat(&fscache_n_op_pend);
		} else if (!list_empty(&object->pending_ops)) {
			atomic_inc(&op->usage);
			list_add_tail(&op->pend_link, &object->pending_ops);
			fscache_stat(&fscache_n_op_pend);
			fscache_start_operations(object);
		} else {
			ASSERTCMP(object->n_in_progress, ==, 0);
			fscache_run_op(object, op);
		}

		/* need to issue a new write op after this */
		clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
		ret = 0;
	} else if (object->state == FSCACHE_OBJECT_CREATING) {
		op->object = object;
		object->n_ops++;
		object->n_exclusive++;	/* reads and writes must wait */
		atomic_inc(&op->usage);
		list_add_tail(&op->pend_link, &object->pending_ops);
		fscache_stat(&fscache_n_op_pend);
		ret = 0;
	} else {
		/* If we're in any other state, there must have been an I/O
		 * error of some nature.
		 */
		ASSERT(test_bit(FSCACHE_IOERROR, &object->cache->flags));
		ret = -EIO;
	}

	spin_unlock(&object->lock);
	return ret;
}

/*
 * report an unexpected submission
 */
static void fscache_report_unexpected_submission(struct fscache_object *object,
						 struct fscache_operation *op,
						 unsigned long ostate)
{
	static bool once_only;
	struct fscache_operation *p;
	unsigned n;

	if (once_only)
		return;
	once_only = true;

	kdebug("unexpected submission OP%x [OBJ%x %s]",
	       op->debug_id, object->debug_id,
	       fscache_object_states[object->state]);
	kdebug("objstate=%s [%s]",
	       fscache_object_states[object->state],
	       fscache_object_states[ostate]);
	kdebug("objflags=%lx", object->flags);
	kdebug("objevent=%lx [%lx]", object->events, object->event_mask);
	kdebug("ops=%u inp=%u exc=%u",
	       object->n_ops, object->n_in_progress, object->n_exclusive);

	if (!list_empty(&object->pending_ops)) {
		n = 0;
		list_for_each_entry(p, &object->pending_ops, pend_link) {
			ASSERTCMP(p->object, ==, object);
			kdebug("%p %p", op->processor, op->release);
			n++;
		}

		kdebug("n=%u", n);
	}

	dump_stack();
}

/*
 * submit an operation for an object
 * - objects may be submitted only in the following states:
 *   - during object creation (write ops may be submitted)
 *   - whilst the object is active
 *   - after an I/O error incurred in one of the two above states (op rejected)
 * - this gets any extra refs it needs on an op
 */
int fscache_submit_op(struct fscache_object *object,
		      struct fscache_operation *op)
{
	unsigned long ostate;
	int ret;

	_enter("{OBJ%x OP%x},{%u}",
	       object->debug_id, op->debug_id, atomic_read(&op->usage));

	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_INITIALISED);
	ASSERTCMP(atomic_read(&op->usage), >, 0);

	spin_lock(&object->lock);
	ASSERTCMP(object->n_ops, >=, object->n_in_progress);
	ASSERTCMP(object->n_ops, >=, object->n_exclusive);
	ASSERT(list_empty(&op->pend_link));

	ostate = object->state;
	smp_rmb();

	op->state = FSCACHE_OP_ST_PENDING;
	if (fscache_object_is_active(object)) {
		op->object = object;
		object->n_ops++;

		if (object->n_exclusive > 0) {
			atomic_inc(&op->usage);
			list_add_tail(&op->pend_link, &object->pending_ops);
			fscache_stat(&fscache_n_op_pend);
		} else if (!list_empty(&object->pending_ops)) {
			atomic_inc(&op->usage);
			list_add_tail(&op->pend_link, &object->pending_ops);
			fscache_stat(&fscache_n_op_pend);
			fscache_start_operations(object);
		} else {
			ASSERTCMP(object->n_exclusive, ==, 0);
			fscache_run_op(object, op);
		}
		ret = 0;
	} else if (object->state == FSCACHE_OBJECT_CREATING) {
		op->object = object;
		object->n_ops++;
		atomic_inc(&op->usage);
		list_add_tail(&op->pend_link, &object->pending_ops);
		fscache_stat(&fscache_n_op_pend);
		ret = 0;
	} else if (object->state == FSCACHE_OBJECT_DYING ||
		   object->state == FSCACHE_OBJECT_LC_DYING ||
		   object->state == FSCACHE_OBJECT_WITHDRAWING) {
		fscache_stat(&fscache_n_op_rejected);
		op->state = FSCACHE_OP_ST_CANCELLED;
		ret = -ENOBUFS;
	} else if (!test_bit(FSCACHE_IOERROR, &object->cache->flags)) {
		fscache_report_unexpected_submission(object, op, ostate);
		ASSERT(!fscache_object_is_active(object));
		op->state = FSCACHE_OP_ST_CANCELLED;
		ret = -ENOBUFS;
	} else {
		op->state = FSCACHE_OP_ST_CANCELLED;
		ret = -ENOBUFS;
	}

	spin_unlock(&object->lock);
	return ret;
}

/*
 * queue an object for withdrawal on error, aborting all following asynchronous
 * operations
 */
void fscache_abort_object(struct fscache_object *object)
{
	_enter("{OBJ%x}", object->debug_id);

	fscache_raise_event(object, FSCACHE_OBJECT_EV_ERROR);
}

/*
 * jump start the operation processing on an object
 * - caller must hold object->lock
 */
void fscache_start_operations(struct fscache_object *object)
{
	struct fscache_operation *op;
	bool stop = false;

	while (!list_empty(&object->pending_ops) && !stop) {
		op = list_entry(object->pending_ops.next,
				struct fscache_operation, pend_link);

		if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags)) {
			if (object->n_in_progress > 0)
				break;
			stop = true;
		}
		list_del_init(&op->pend_link);
		fscache_run_op(object, op);

		/* the pending queue was holding a ref on the object */
		fscache_put_operation(op);
	}

	ASSERTCMP(object->n_in_progress, <=, object->n_ops);

	_debug("woke %d ops on OBJ%x",
	       object->n_in_progress, object->debug_id);
}

/*
 * cancel an operation that's pending on an object
 */
int fscache_cancel_op(struct fscache_operation *op,
		      void (*do_cancel)(struct fscache_operation *))
{
	struct fscache_object *object = op->object;
	int ret;

	_enter("OBJ%x OP%x}", op->object->debug_id, op->debug_id);

	ASSERTCMP(op->state, >=, FSCACHE_OP_ST_PENDING);
	ASSERTCMP(op->state, !=, FSCACHE_OP_ST_CANCELLED);
	ASSERTCMP(atomic_read(&op->usage), >, 0);

	spin_lock(&object->lock);

	ret = -EBUSY;
	if (op->state == FSCACHE_OP_ST_PENDING) {
		ASSERT(!list_empty(&op->pend_link));
		fscache_stat(&fscache_n_op_cancelled);
		list_del_init(&op->pend_link);
		if (do_cancel)
			do_cancel(op);
		op->state = FSCACHE_OP_ST_CANCELLED;
		if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
			object->n_exclusive--;
		if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
			wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
		fscache_put_operation(op);
		ret = 0;
	}

	spin_unlock(&object->lock);
	_leave(" = %d", ret);
	return ret;
}

/*
 * Cancel all pending operations on an object
 */
void fscache_cancel_all_ops(struct fscache_object *object)
{
	struct fscache_operation *op;

	_enter("OBJ%x", object->debug_id);

	spin_lock(&object->lock);

	while (!list_empty(&object->pending_ops)) {
		op = list_entry(object->pending_ops.next,
				struct fscache_operation, pend_link);
		fscache_stat(&fscache_n_op_cancelled);
		list_del_init(&op->pend_link);

		ASSERTCMP(op->state, ==, FSCACHE_OP_ST_PENDING);
		op->state = FSCACHE_OP_ST_CANCELLED;

		if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
			object->n_exclusive--;
		if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
			wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
		fscache_put_operation(op);
		cond_resched_lock(&object->lock);
	}

	spin_unlock(&object->lock);
	_leave("");
}

/*
 * Record the completion or cancellation of an in-progress operation.
 */
void fscache_op_complete(struct fscache_operation *op, bool cancelled)
{
	struct fscache_object *object = op->object;

	_enter("OBJ%x", object->debug_id);

	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_IN_PROGRESS);
	ASSERTCMP(object->n_in_progress, >, 0);
	ASSERTIFCMP(test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags),
		    object->n_exclusive, >, 0);
	ASSERTIFCMP(test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags),
		    object->n_in_progress, ==, 1);

	spin_lock(&object->lock);

	op->state = cancelled ?
		FSCACHE_OP_ST_CANCELLED : FSCACHE_OP_ST_COMPLETE;

	if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
		object->n_exclusive--;
	object->n_in_progress--;
	if (object->n_in_progress == 0)
		fscache_start_operations(object);

	spin_unlock(&object->lock);
	_leave("");
}
EXPORT_SYMBOL(fscache_op_complete);

/*
 * release an operation
 * - queues pending ops if this is the last in-progress op
 */
void fscache_put_operation(struct fscache_operation *op)
{
	struct fscache_object *object;
	struct fscache_cache *cache;

	_enter("{OBJ%x OP%x,%d}",
	       op->object->debug_id, op->debug_id, atomic_read(&op->usage));

	ASSERTCMP(atomic_read(&op->usage), >, 0);

	if (!atomic_dec_and_test(&op->usage))
		return;

	_debug("PUT OP");
	ASSERTIFCMP(op->state != FSCACHE_OP_ST_COMPLETE,
		    op->state, ==, FSCACHE_OP_ST_CANCELLED);
	op->state = FSCACHE_OP_ST_DEAD;

	fscache_stat(&fscache_n_op_release);

	if (op->release) {
		op->release(op);
		op->release = NULL;
	}

	object = op->object;

	if (test_bit(FSCACHE_OP_DEC_READ_CNT, &op->flags)) {
		if (atomic_dec_and_test(&object->n_reads)) {
			clear_bit(FSCACHE_COOKIE_WAITING_ON_READS,
				  &object->cookie->flags);
			wake_up_bit(&object->cookie->flags,
				    FSCACHE_COOKIE_WAITING_ON_READS);
		}
	}

	/* now... we may get called with the object spinlock held, so we
	 * complete the cleanup here only if we can immediately acquire the
	 * lock, and defer it otherwise */
	if (!spin_trylock(&object->lock)) {
		_debug("defer put");
		fscache_stat(&fscache_n_op_deferred_release);

		cache = object->cache;
		spin_lock(&cache->op_gc_list_lock);
		list_add_tail(&op->pend_link, &cache->op_gc_list);
		spin_unlock(&cache->op_gc_list_lock);
		schedule_work(&cache->op_gc);
		_leave(" [defer]");
		return;
	}

	ASSERTCMP(object->n_ops, >, 0);
	object->n_ops--;
	if (object->n_ops == 0)
		fscache_raise_event(object, FSCACHE_OBJECT_EV_CLEARED);

	spin_unlock(&object->lock);

	kfree(op);
	_leave(" [done]");
}
EXPORT_SYMBOL(fscache_put_operation);

/*
 * garbage collect operations that have had their release deferred
 */
void fscache_operation_gc(struct work_struct *work)
{
	struct fscache_operation *op;
	struct fscache_object *object;
	struct fscache_cache *cache =
		container_of(work, struct fscache_cache, op_gc);
	int count = 0;

	_enter("");

	do {
		spin_lock(&cache->op_gc_list_lock);
		if (list_empty(&cache->op_gc_list)) {
			spin_unlock(&cache->op_gc_list_lock);
			break;
		}

		op = list_entry(cache->op_gc_list.next,
				struct fscache_operation, pend_link);
		list_del(&op->pend_link);
		spin_unlock(&cache->op_gc_list_lock);

		object = op->object;
		spin_lock(&object->lock);

		_debug("GC DEFERRED REL OBJ%x OP%x",
		       object->debug_id, op->debug_id);
		fscache_stat(&fscache_n_op_gc);

		ASSERTCMP(atomic_read(&op->usage), ==, 0);
		ASSERTCMP(op->state, ==, FSCACHE_OP_ST_DEAD);

		ASSERTCMP(object->n_ops, >, 0);
		object->n_ops--;
		if (object->n_ops == 0)
			fscache_raise_event(object, FSCACHE_OBJECT_EV_CLEARED);

		spin_unlock(&object->lock);
		kfree(op);

	} while (count++ < 20);

	if (!list_empty(&cache->op_gc_list))
		schedule_work(&cache->op_gc);

	_leave("");
}

/*
 * execute an operation using fs_op_wq to provide processing context -
 * the caller holds a ref to this object, so we don't need to hold one
 */
void fscache_op_work_func(struct work_struct *work)
{
	struct fscache_operation *op =
		container_of(work, struct fscache_operation, work);
	unsigned long start;

	_enter("{OBJ%x OP%x,%d}",
	       op->object->debug_id, op->debug_id, atomic_read(&op->usage));

	ASSERT(op->processor != NULL);
	start = jiffies;
	op->processor(op);
	fscache_hist(fscache_ops_histogram, start);
	fscache_put_operation(op);

	_leave("");
}
Commit	Line	Data
952efe7b DH	1	/* FS-Cache worker operation management routines
	2	*
	3	* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
	4	* Written by David Howells (dhowells@redhat.com)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*
	11	* See Documentation/filesystems/caching/operations.txt
	12	*/
	13
	14	#define FSCACHE_DEBUG_LEVEL OPERATION
	15	#include <linux/module.h>
440f0aff	16	#include <linux/seq_file.h>
5a0e3ad6	17	#include <linux/slab.h>
952efe7b DH	18	#include "internal.h"
	19
	20	atomic_t fscache_op_debug_id;
	21	EXPORT_SYMBOL(fscache_op_debug_id);
	22
	23	/**
	24	* fscache_enqueue_operation - Enqueue an operation for processing
	25	* @op: The operation to enqueue
	26	*
	27	* Enqueue an operation for processing by the FS-Cache thread pool.
	28	*
	29	* This will get its own ref on the object.
	30	*/
	31	void fscache_enqueue_operation(struct fscache_operation *op)
	32	{
	33	_enter("{OBJ%x OP%x,%u}",
	34	op->object->debug_id, op->debug_id, atomic_read(&op->usage));
	35
5753c441	36	ASSERT(list_empty(&op->pend_link));
952efe7b DH	37	ASSERT(op->processor != NULL);
	38	ASSERTCMP(op->object->state, >=, FSCACHE_OBJECT_AVAILABLE);
	39	ASSERTCMP(atomic_read(&op->usage), >, 0);
9f10523f	40	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_IN_PROGRESS);
952efe7b	41
5753c441 DH	42	fscache_stat(&fscache_n_op_enqueue);
5753c441 DH	43	switch (op->flags & FSCACHE_OP_TYPE) {
8af7c124 TH	44	case FSCACHE_OP_ASYNC:
8af7c124 TH	45	_debug("queue async");
5753c441	46	atomic_inc(&op->usage);
8af7c124	47	if (!queue_work(fscache_op_wq, &op->work))
5753c441 DH	48	fscache_put_operation(op);
5753c441 DH	49	break;
5753c441 DH	50	case FSCACHE_OP_MYTHREAD:
	51	_debug("queue for caller's attention");
	52	break;
	53	default:
	54	printk(KERN_ERR "FS-Cache: Unexpected op type %lx",
	55	op->flags);
	56	BUG();
	57	break;
952efe7b DH	58	}
	59	}
	60	EXPORT_SYMBOL(fscache_enqueue_operation);
	61
	62	/*
	63	* start an op running
	64	*/
	65	static void fscache_run_op(struct fscache_object *object,
	66	struct fscache_operation *op)
	67	{
9f10523f DH	68	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_PENDING);
	69
	70	op->state = FSCACHE_OP_ST_IN_PROGRESS;
952efe7b DH	71	object->n_in_progress++;
	72	if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
	73	wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
	74	if (op->processor)
	75	fscache_enqueue_operation(op);
	76	fscache_stat(&fscache_n_op_run);
	77	}
	78
	79	/*
	80	* submit an exclusive operation for an object
	81	* - other ops are excluded from running simultaneously with this one
	82	* - this gets any extra refs it needs on an op
	83	*/
	84	int fscache_submit_exclusive_op(struct fscache_object *object,
	85	struct fscache_operation *op)
	86	{
8d76349d DH	87	int ret;
8d76349d DH	88
952efe7b DH	89	_enter("{OBJ%x OP%x},", object->debug_id, op->debug_id);
952efe7b DH	90
9f10523f DH	91	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_INITIALISED);
	92	ASSERTCMP(atomic_read(&op->usage), >, 0);
	93
952efe7b DH	94	spin_lock(&object->lock);
	95	ASSERTCMP(object->n_ops, >=, object->n_in_progress);
	96	ASSERTCMP(object->n_ops, >=, object->n_exclusive);
5753c441	97	ASSERT(list_empty(&op->pend_link));
952efe7b	98
9f10523f	99	op->state = FSCACHE_OP_ST_PENDING;
952efe7b DH	100	if (fscache_object_is_active(object)) {
	101	op->object = object;
	102	object->n_ops++;
	103	object->n_exclusive++; /* reads and writes must wait */
	104
9f10523f	105	if (object->n_in_progress > 0) {
952efe7b DH	106	atomic_inc(&op->usage);
	107	list_add_tail(&op->pend_link, &object->pending_ops);
	108	fscache_stat(&fscache_n_op_pend);
	109	} else if (!list_empty(&object->pending_ops)) {
	110	atomic_inc(&op->usage);
	111	list_add_tail(&op->pend_link, &object->pending_ops);
	112	fscache_stat(&fscache_n_op_pend);
	113	fscache_start_operations(object);
	114	} else {
	115	ASSERTCMP(object->n_in_progress, ==, 0);
	116	fscache_run_op(object, op);
	117	}
	118
	119	/* need to issue a new write op after this */
	120	clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
8d76349d	121	ret = 0;
952efe7b DH	122	} else if (object->state == FSCACHE_OBJECT_CREATING) {
	123	op->object = object;
	124	object->n_ops++;
	125	object->n_exclusive++; /* reads and writes must wait */
	126	atomic_inc(&op->usage);
	127	list_add_tail(&op->pend_link, &object->pending_ops);
	128	fscache_stat(&fscache_n_op_pend);
8d76349d	129	ret = 0;
952efe7b	130	} else {
8d76349d DH	131	/* If we're in any other state, there must have been an I/O
	132	* error of some nature.
	133	*/
	134	ASSERT(test_bit(FSCACHE_IOERROR, &object->cache->flags));
	135	ret = -EIO;
952efe7b DH	136	}
	137
	138	spin_unlock(&object->lock);
8d76349d	139	return ret;
952efe7b DH	140	}
	141
	142	/*
	143	* report an unexpected submission
	144	*/
	145	static void fscache_report_unexpected_submission(struct fscache_object *object,
	146	struct fscache_operation *op,
	147	unsigned long ostate)
	148	{
	149	static bool once_only;
	150	struct fscache_operation *p;
	151	unsigned n;
	152
	153	if (once_only)
	154	return;
	155	once_only = true;
	156
	157	kdebug("unexpected submission OP%x [OBJ%x %s]",
	158	op->debug_id, object->debug_id,
	159	fscache_object_states[object->state]);
	160	kdebug("objstate=%s [%s]",
	161	fscache_object_states[object->state],
	162	fscache_object_states[ostate]);
	163	kdebug("objflags=%lx", object->flags);
	164	kdebug("objevent=%lx [%lx]", object->events, object->event_mask);
	165	kdebug("ops=%u inp=%u exc=%u",
	166	object->n_ops, object->n_in_progress, object->n_exclusive);
	167
	168	if (!list_empty(&object->pending_ops)) {
	169	n = 0;
	170	list_for_each_entry(p, &object->pending_ops, pend_link) {
	171	ASSERTCMP(p->object, ==, object);
	172	kdebug("%p %p", op->processor, op->release);
	173	n++;
	174	}
	175
	176	kdebug("n=%u", n);
	177	}
	178
	179	dump_stack();
	180	}
	181
	182	/*
	183	* submit an operation for an object
	184	* - objects may be submitted only in the following states:
	185	* - during object creation (write ops may be submitted)
	186	* - whilst the object is active
	187	* - after an I/O error incurred in one of the two above states (op rejected)
	188	* - this gets any extra refs it needs on an op
	189	*/
	190	int fscache_submit_op(struct fscache_object *object,
	191	struct fscache_operation *op)
	192	{
	193	unsigned long ostate;
	194	int ret;
	195
	196	_enter("{OBJ%x OP%x},{%u}",
	197	object->debug_id, op->debug_id, atomic_read(&op->usage));
	198
9f10523f	199	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_INITIALISED);
952efe7b DH	200	ASSERTCMP(atomic_read(&op->usage), >, 0);
	201
	202	spin_lock(&object->lock);
	203	ASSERTCMP(object->n_ops, >=, object->n_in_progress);
	204	ASSERTCMP(object->n_ops, >=, object->n_exclusive);
5753c441	205	ASSERT(list_empty(&op->pend_link));
952efe7b DH	206
	207	ostate = object->state;
	208	smp_rmb();
	209
9f10523f	210	op->state = FSCACHE_OP_ST_PENDING;
952efe7b DH	211	if (fscache_object_is_active(object)) {
	212	op->object = object;
	213	object->n_ops++;
	214
	215	if (object->n_exclusive > 0) {
	216	atomic_inc(&op->usage);
	217	list_add_tail(&op->pend_link, &object->pending_ops);
	218	fscache_stat(&fscache_n_op_pend);
	219	} else if (!list_empty(&object->pending_ops)) {
	220	atomic_inc(&op->usage);
	221	list_add_tail(&op->pend_link, &object->pending_ops);
	222	fscache_stat(&fscache_n_op_pend);
	223	fscache_start_operations(object);
	224	} else {
	225	ASSERTCMP(object->n_exclusive, ==, 0);
	226	fscache_run_op(object, op);
	227	}
	228	ret = 0;
	229	} else if (object->state == FSCACHE_OBJECT_CREATING) {
	230	op->object = object;
	231	object->n_ops++;
	232	atomic_inc(&op->usage);
	233	list_add_tail(&op->pend_link, &object->pending_ops);
	234	fscache_stat(&fscache_n_op_pend);
	235	ret = 0;
e3d4d28b DH	236	} else if (object->state == FSCACHE_OBJECT_DYING \|\|
	237	object->state == FSCACHE_OBJECT_LC_DYING \|\|
	238	object->state == FSCACHE_OBJECT_WITHDRAWING) {
	239	fscache_stat(&fscache_n_op_rejected);
9f10523f	240	op->state = FSCACHE_OP_ST_CANCELLED;
e3d4d28b	241	ret = -ENOBUFS;
952efe7b DH	242	} else if (!test_bit(FSCACHE_IOERROR, &object->cache->flags)) {
	243	fscache_report_unexpected_submission(object, op, ostate);
	244	ASSERT(!fscache_object_is_active(object));
9f10523f	245	op->state = FSCACHE_OP_ST_CANCELLED;
952efe7b DH	246	ret = -ENOBUFS;
952efe7b DH	247	} else {
9f10523f	248	op->state = FSCACHE_OP_ST_CANCELLED;
952efe7b DH	249	ret = -ENOBUFS;
	250	}
	251
	252	spin_unlock(&object->lock);
	253	return ret;
	254	}
	255
	256	/*
	257	* queue an object for withdrawal on error, aborting all following asynchronous
	258	* operations
	259	*/
	260	void fscache_abort_object(struct fscache_object *object)
	261	{
	262	_enter("{OBJ%x}", object->debug_id);
	263
	264	fscache_raise_event(object, FSCACHE_OBJECT_EV_ERROR);
	265	}
	266
	267	/*
	268	* jump start the operation processing on an object
	269	* - caller must hold object->lock
	270	*/
	271	void fscache_start_operations(struct fscache_object *object)
	272	{
	273	struct fscache_operation *op;
	274	bool stop = false;
	275
	276	while (!list_empty(&object->pending_ops) && !stop) {
	277	op = list_entry(object->pending_ops.next,
	278	struct fscache_operation, pend_link);
	279
	280	if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags)) {
	281	if (object->n_in_progress > 0)
	282	break;
	283	stop = true;
	284	}
	285	list_del_init(&op->pend_link);
5753c441	286	fscache_run_op(object, op);
952efe7b DH	287
	288	/* the pending queue was holding a ref on the object */
	289	fscache_put_operation(op);
	290	}
	291
	292	ASSERTCMP(object->n_in_progress, <=, object->n_ops);
	293
	294	_debug("woke %d ops on OBJ%x",
	295	object->n_in_progress, object->debug_id);
	296	}
	297
5753c441 DH	298	/*
	299	* cancel an operation that's pending on an object
	300	*/
91c7fbbf DH	301	int fscache_cancel_op(struct fscache_operation *op,
91c7fbbf DH	302	void (do_cancel)(struct fscache_operation ))
5753c441 DH	303	{
	304	struct fscache_object *object = op->object;
	305	int ret;
	306
	307	_enter("OBJ%x OP%x}", op->object->debug_id, op->debug_id);
	308
9f10523f DH	309	ASSERTCMP(op->state, >=, FSCACHE_OP_ST_PENDING);
	310	ASSERTCMP(op->state, !=, FSCACHE_OP_ST_CANCELLED);
	311	ASSERTCMP(atomic_read(&op->usage), >, 0);
	312
5753c441 DH	313	spin_lock(&object->lock);
	314
	315	ret = -EBUSY;
9f10523f DH	316	if (op->state == FSCACHE_OP_ST_PENDING) {
9f10523f DH	317	ASSERT(!list_empty(&op->pend_link));
5753c441 DH	318	fscache_stat(&fscache_n_op_cancelled);
5753c441 DH	319	list_del_init(&op->pend_link);
91c7fbbf DH	320	if (do_cancel)
91c7fbbf DH	321	do_cancel(op);
9f10523f	322	op->state = FSCACHE_OP_ST_CANCELLED;
5753c441 DH	323	if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
	324	object->n_exclusive--;
	325	if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
	326	wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
	327	fscache_put_operation(op);
	328	ret = 0;
	329	}
	330
	331	spin_unlock(&object->lock);
	332	_leave(" = %d", ret);
	333	return ret;
	334	}
	335
ef778e7a DH	336	/*
	337	* Cancel all pending operations on an object
	338	*/
	339	void fscache_cancel_all_ops(struct fscache_object *object)
	340	{
	341	struct fscache_operation *op;
	342
	343	_enter("OBJ%x", object->debug_id);
	344
	345	spin_lock(&object->lock);
	346
	347	while (!list_empty(&object->pending_ops)) {
	348	op = list_entry(object->pending_ops.next,
	349	struct fscache_operation, pend_link);
	350	fscache_stat(&fscache_n_op_cancelled);
	351	list_del_init(&op->pend_link);
	352
	353	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_PENDING);
	354	op->state = FSCACHE_OP_ST_CANCELLED;
	355
	356	if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
	357	object->n_exclusive--;
	358	if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
	359	wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
	360	fscache_put_operation(op);
	361	cond_resched_lock(&object->lock);
	362	}
	363
	364	spin_unlock(&object->lock);
	365	_leave("");
	366	}
	367
9f10523f	368	/*
1f372dff	369	* Record the completion or cancellation of an in-progress operation.
9f10523f	370	*/
1f372dff	371	void fscache_op_complete(struct fscache_operation *op, bool cancelled)
9f10523f DH	372	{
	373	struct fscache_object *object = op->object;
	374
	375	_enter("OBJ%x", object->debug_id);
	376
	377	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_IN_PROGRESS);
	378	ASSERTCMP(object->n_in_progress, >, 0);
	379	ASSERTIFCMP(test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags),
	380	object->n_exclusive, >, 0);
	381	ASSERTIFCMP(test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags),
	382	object->n_in_progress, ==, 1);
	383
	384	spin_lock(&object->lock);
	385
1f372dff DH	386	op->state = cancelled ?
1f372dff DH	387	FSCACHE_OP_ST_CANCELLED : FSCACHE_OP_ST_COMPLETE;
9f10523f DH	388
	389	if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
	390	object->n_exclusive--;
	391	object->n_in_progress--;
	392	if (object->n_in_progress == 0)
	393	fscache_start_operations(object);
	394
	395	spin_unlock(&object->lock);
	396	_leave("");
	397	}
	398	EXPORT_SYMBOL(fscache_op_complete);
	399
952efe7b DH	400	/*
	401	* release an operation
	402	* - queues pending ops if this is the last in-progress op
	403	*/
	404	void fscache_put_operation(struct fscache_operation *op)
	405	{
	406	struct fscache_object *object;
	407	struct fscache_cache *cache;
	408
	409	_enter("{OBJ%x OP%x,%d}",
	410	op->object->debug_id, op->debug_id, atomic_read(&op->usage));
	411
	412	ASSERTCMP(atomic_read(&op->usage), >, 0);
	413
	414	if (!atomic_dec_and_test(&op->usage))
	415	return;
	416
	417	_debug("PUT OP");
9f10523f DH	418	ASSERTIFCMP(op->state != FSCACHE_OP_ST_COMPLETE,
	419	op->state, ==, FSCACHE_OP_ST_CANCELLED);
	420	op->state = FSCACHE_OP_ST_DEAD;
952efe7b DH	421
	422	fscache_stat(&fscache_n_op_release);
	423
	424	if (op->release) {
	425	op->release(op);
	426	op->release = NULL;
	427	}
	428
	429	object = op->object;
	430
ef46ed88 DH	431	if (test_bit(FSCACHE_OP_DEC_READ_CNT, &op->flags)) {
	432	if (atomic_dec_and_test(&object->n_reads)) {
	433	clear_bit(FSCACHE_COOKIE_WAITING_ON_READS,
	434	&object->cookie->flags);
	435	wake_up_bit(&object->cookie->flags,
	436	FSCACHE_COOKIE_WAITING_ON_READS);
	437	}
	438	}
4fbf4291	439
952efe7b DH	440	/* now... we may get called with the object spinlock held, so we
	441	* complete the cleanup here only if we can immediately acquire the
	442	* lock, and defer it otherwise */
	443	if (!spin_trylock(&object->lock)) {
	444	_debug("defer put");
	445	fscache_stat(&fscache_n_op_deferred_release);
	446
	447	cache = object->cache;
	448	spin_lock(&cache->op_gc_list_lock);
	449	list_add_tail(&op->pend_link, &cache->op_gc_list);
	450	spin_unlock(&cache->op_gc_list_lock);
	451	schedule_work(&cache->op_gc);
	452	_leave(" [defer]");
	453	return;
	454	}
	455
952efe7b DH	456	ASSERTCMP(object->n_ops, >, 0);
	457	object->n_ops--;
	458	if (object->n_ops == 0)
	459	fscache_raise_event(object, FSCACHE_OBJECT_EV_CLEARED);
	460
	461	spin_unlock(&object->lock);
	462
	463	kfree(op);
	464	_leave(" [done]");
	465	}
	466	EXPORT_SYMBOL(fscache_put_operation);
	467
	468	/*
	469	* garbage collect operations that have had their release deferred
	470	*/
	471	void fscache_operation_gc(struct work_struct *work)
	472	{
	473	struct fscache_operation *op;
	474	struct fscache_object *object;
	475	struct fscache_cache *cache =
	476	container_of(work, struct fscache_cache, op_gc);
	477	int count = 0;
	478
	479	_enter("");
	480
	481	do {
	482	spin_lock(&cache->op_gc_list_lock);
	483	if (list_empty(&cache->op_gc_list)) {
	484	spin_unlock(&cache->op_gc_list_lock);
	485	break;
	486	}
	487
	488	op = list_entry(cache->op_gc_list.next,
	489	struct fscache_operation, pend_link);
	490	list_del(&op->pend_link);
	491	spin_unlock(&cache->op_gc_list_lock);
	492
	493	object = op->object;
9f10523f	494	spin_lock(&object->lock);
952efe7b DH	495
	496	_debug("GC DEFERRED REL OBJ%x OP%x",
	497	object->debug_id, op->debug_id);
	498	fscache_stat(&fscache_n_op_gc);
	499
	500	ASSERTCMP(atomic_read(&op->usage), ==, 0);
9f10523f	501	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_DEAD);
952efe7b DH	502
	503	ASSERTCMP(object->n_ops, >, 0);
	504	object->n_ops--;
	505	if (object->n_ops == 0)
	506	fscache_raise_event(object, FSCACHE_OBJECT_EV_CLEARED);
	507
	508	spin_unlock(&object->lock);
9f10523f	509	kfree(op);
952efe7b DH	510
	511	} while (count++ < 20);
	512
	513	if (!list_empty(&cache->op_gc_list))
	514	schedule_work(&cache->op_gc);
	515
	516	_leave("");
	517	}
	518
	519	/*
8af7c124 TH	520	* execute an operation using fs_op_wq to provide processing context -
8af7c124 TH	521	* the caller holds a ref to this object, so we don't need to hold one
952efe7b	522	*/
8af7c124	523	void fscache_op_work_func(struct work_struct *work)
952efe7b DH	524	{
952efe7b DH	525	struct fscache_operation *op =
8af7c124	526	container_of(work, struct fscache_operation, work);
952efe7b DH	527	unsigned long start;
	528
	529	_enter("{OBJ%x OP%x,%d}",
	530	op->object->debug_id, op->debug_id, atomic_read(&op->usage));
	531
	532	ASSERT(op->processor != NULL);
	533	start = jiffies;
	534	op->processor(op);
	535	fscache_hist(fscache_ops_histogram, start);
8af7c124	536	fscache_put_operation(op);
952efe7b DH	537
	538	_leave("");
	539	}