[deliverable/linux.git] / drivers / md / persistent-data / dm-space-map-metadata.c

/*
 * Copyright (C) 2011 Red Hat, Inc.
 *
 * This file is released under the GPL.
 */

#include "dm-space-map.h"
#include "dm-space-map-common.h"
#include "dm-space-map-metadata.h"

#include <linux/list.h>
#include <linux/slab.h>
#include <linux/device-mapper.h>

#define DM_MSG_PREFIX "space map metadata"

/*----------------------------------------------------------------*/

/*
 * An edge triggered threshold.
 */
struct threshold {
	bool threshold_set;
	bool value_set;
	dm_block_t threshold;
	dm_block_t current_value;
	dm_sm_threshold_fn fn;
	void *context;
};

static void threshold_init(struct threshold *t)
{
	t->threshold_set = false;
	t->value_set = false;
}

static void set_threshold(struct threshold *t, dm_block_t value,
			  dm_sm_threshold_fn fn, void *context)
{
	t->threshold_set = true;
	t->threshold = value;
	t->fn = fn;
	t->context = context;
}

static bool below_threshold(struct threshold *t, dm_block_t value)
{
	return t->threshold_set && value <= t->threshold;
}

static bool threshold_already_triggered(struct threshold *t)
{
	return t->value_set && below_threshold(t, t->current_value);
}

static void check_threshold(struct threshold *t, dm_block_t value)
{
	if (below_threshold(t, value) &&
	    !threshold_already_triggered(t))
		t->fn(t->context);

	t->value_set = true;
	t->current_value = value;
}

/*----------------------------------------------------------------*/

/*
 * Space map interface.
 *
 * The low level disk format is written using the standard btree and
 * transaction manager.  This means that performing disk operations may
 * cause us to recurse into the space map in order to allocate new blocks.
 * For this reason we have a pool of pre-allocated blocks large enough to
 * service any metadata_ll_disk operation.
 */

/*
 * FIXME: we should calculate this based on the size of the device.
 * Only the metadata space map needs this functionality.
 */
#define MAX_RECURSIVE_ALLOCATIONS 1024

enum block_op_type {
	BOP_INC,
	BOP_DEC
};

struct block_op {
	enum block_op_type type;
	dm_block_t block;
};

struct bop_ring_buffer {
	unsigned begin;
	unsigned end;
	struct block_op bops[MAX_RECURSIVE_ALLOCATIONS + 1];
};

static void brb_init(struct bop_ring_buffer *brb)
{
	brb->begin = 0;
	brb->end = 0;
}

static bool brb_empty(struct bop_ring_buffer *brb)
{
	return brb->begin == brb->end;
}

static unsigned brb_next(struct bop_ring_buffer *brb, unsigned old)
{
	unsigned r = old + 1;
	return (r >= (sizeof(brb->bops) / sizeof(*brb->bops))) ? 0 : r;
}

static int brb_push(struct bop_ring_buffer *brb,
		    enum block_op_type type, dm_block_t b)
{
	struct block_op *bop;
	unsigned next = brb_next(brb, brb->end);

	/*
	 * We don't allow the last bop to be filled, this way we can
	 * differentiate between full and empty.
	 */
	if (next == brb->begin)
		return -ENOMEM;

	bop = brb->bops + brb->end;
	bop->type = type;
	bop->block = b;

	brb->end = next;

	return 0;
}

static int brb_pop(struct bop_ring_buffer *brb, struct block_op *result)
{
	struct block_op *bop;

	if (brb_empty(brb))
		return -ENODATA;

	bop = brb->bops + brb->begin;
	result->type = bop->type;
	result->block = bop->block;

	brb->begin = brb_next(brb, brb->begin);

	return 0;
}

/*----------------------------------------------------------------*/

struct sm_metadata {
	struct dm_space_map sm;

	struct ll_disk ll;
	struct ll_disk old_ll;

	dm_block_t begin;

	unsigned recursion_count;
	unsigned allocated_this_transaction;
	struct bop_ring_buffer uncommitted;

	struct threshold threshold;
};

static int add_bop(struct sm_metadata *smm, enum block_op_type type, dm_block_t b)
{
	int r = brb_push(&smm->uncommitted, type, b);

	if (r) {
		DMERR("too many recursive allocations");
		return -ENOMEM;
	}

	return 0;
}

static int commit_bop(struct sm_metadata *smm, struct block_op *op)
{
	int r = 0;
	enum allocation_event ev;

	switch (op->type) {
	case BOP_INC:
		r = sm_ll_inc(&smm->ll, op->block, &ev);
		break;

	case BOP_DEC:
		r = sm_ll_dec(&smm->ll, op->block, &ev);
		break;
	}

	return r;
}

static void in(struct sm_metadata *smm)
{
	smm->recursion_count++;
}

static int out(struct sm_metadata *smm)
{
	int r = 0;

	/*
	 * If we're not recursing then very bad things are happening.
	 */
	if (!smm->recursion_count) {
		DMERR("lost track of recursion depth");
		return -ENOMEM;
	}

	if (smm->recursion_count == 1) {
		while (!brb_empty(&smm->uncommitted)) {
			struct block_op bop;

			r = brb_pop(&smm->uncommitted, &bop);
			if (r) {
				DMERR("bug in bop ring buffer");
				break;
			}

			r = commit_bop(smm, &bop);
			if (r)
				break;
		}
	}

	smm->recursion_count--;

	return r;
}

/*
 * When using the out() function above, we often want to combine an error
 * code for the operation run in the recursive context with that from
 * out().
 */
static int combine_errors(int r1, int r2)
{
	return r1 ? r1 : r2;
}

static int recursing(struct sm_metadata *smm)
{
	return smm->recursion_count;
}

static void sm_metadata_destroy(struct dm_space_map *sm)
{
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);

	kfree(smm);
}

static int sm_metadata_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
{
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);

	*count = smm->ll.nr_blocks;

	return 0;
}

static int sm_metadata_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
{
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);

	*count = smm->old_ll.nr_blocks - smm->old_ll.nr_allocated -
		 smm->allocated_this_transaction;

	return 0;
}

static int sm_metadata_get_count(struct dm_space_map *sm, dm_block_t b,
				 uint32_t *result)
{
	int r;
	unsigned i;
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	unsigned adjustment = 0;

	/*
	 * We may have some uncommitted adjustments to add.  This list
	 * should always be really short.
	 */
	for (i = smm->uncommitted.begin;
	     i != smm->uncommitted.end;
	     i = brb_next(&smm->uncommitted, i)) {
		struct block_op *op = smm->uncommitted.bops + i;

		if (op->block != b)
			continue;

		switch (op->type) {
		case BOP_INC:
			adjustment++;
			break;

		case BOP_DEC:
			adjustment--;
			break;
		}
	}

	r = sm_ll_lookup(&smm->ll, b, result);
	if (r)
		return r;

	*result += adjustment;

	return 0;
}

static int sm_metadata_count_is_more_than_one(struct dm_space_map *sm,
					      dm_block_t b, int *result)
{
	int r, adjustment = 0;
	unsigned i;
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	uint32_t rc;

	/*
	 * We may have some uncommitted adjustments to add.  This list
	 * should always be really short.
	 */
	for (i = smm->uncommitted.begin;
	     i != smm->uncommitted.end;
	     i = brb_next(&smm->uncommitted, i)) {

		struct block_op *op = smm->uncommitted.bops + i;

		if (op->block != b)
			continue;

		switch (op->type) {
		case BOP_INC:
			adjustment++;
			break;

		case BOP_DEC:
			adjustment--;
			break;
		}
	}

	if (adjustment > 1) {
		*result = 1;
		return 0;
	}

	r = sm_ll_lookup_bitmap(&smm->ll, b, &rc);
	if (r)
		return r;

	if (rc == 3)
		/*
		 * We err on the side of caution, and always return true.
		 */
		*result = 1;
	else
		*result = rc + adjustment > 1;

	return 0;
}

static int sm_metadata_set_count(struct dm_space_map *sm, dm_block_t b,
				 uint32_t count)
{
	int r, r2;
	enum allocation_event ev;
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);

	if (smm->recursion_count) {
		DMERR("cannot recurse set_count()");
		return -EINVAL;
	}

	in(smm);
	r = sm_ll_insert(&smm->ll, b, count, &ev);
	r2 = out(smm);

	return combine_errors(r, r2);
}

static int sm_metadata_inc_block(struct dm_space_map *sm, dm_block_t b)
{
	int r, r2 = 0;
	enum allocation_event ev;
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);

	if (recursing(smm))
		r = add_bop(smm, BOP_INC, b);
	else {
		in(smm);
		r = sm_ll_inc(&smm->ll, b, &ev);
		r2 = out(smm);
	}

	return combine_errors(r, r2);
}

static int sm_metadata_dec_block(struct dm_space_map *sm, dm_block_t b)
{
	int r, r2 = 0;
	enum allocation_event ev;
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);

	if (recursing(smm))
		r = add_bop(smm, BOP_DEC, b);
	else {
		in(smm);
		r = sm_ll_dec(&smm->ll, b, &ev);
		r2 = out(smm);
	}

	return combine_errors(r, r2);
}

static int sm_metadata_new_block_(struct dm_space_map *sm, dm_block_t *b)
{
	int r, r2 = 0;
	enum allocation_event ev;
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);

	r = sm_ll_find_free_block(&smm->old_ll, smm->begin, smm->old_ll.nr_blocks, b);
	if (r)
		return r;

	smm->begin = *b + 1;

	if (recursing(smm))
		r = add_bop(smm, BOP_INC, *b);
	else {
		in(smm);
		r = sm_ll_inc(&smm->ll, *b, &ev);
		r2 = out(smm);
	}

	if (!r)
		smm->allocated_this_transaction++;

	return combine_errors(r, r2);
}

static int sm_metadata_new_block(struct dm_space_map *sm, dm_block_t *b)
{
	dm_block_t count;
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);

	int r = sm_metadata_new_block_(sm, b);
	if (r) {
		DMERR_LIMIT("unable to allocate new metadata block");
		return r;
	}

	r = sm_metadata_get_nr_free(sm, &count);
	if (r) {
		DMERR_LIMIT("couldn't get free block count");
		return r;
	}

	check_threshold(&smm->threshold, count);

	return r;
}

static int sm_metadata_commit(struct dm_space_map *sm)
{
	int r;
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);

	r = sm_ll_commit(&smm->ll);
	if (r)
		return r;

	memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
	smm->begin = 0;
	smm->allocated_this_transaction = 0;

	return 0;
}

static int sm_metadata_register_threshold_callback(struct dm_space_map *sm,
						   dm_block_t threshold,
						   dm_sm_threshold_fn fn,
						   void *context)
{
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);

	set_threshold(&smm->threshold, threshold, fn, context);

	return 0;
}

static int sm_metadata_root_size(struct dm_space_map *sm, size_t *result)
{
	*result = sizeof(struct disk_sm_root);

	return 0;
}

static int sm_metadata_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
{
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	struct disk_sm_root root_le;

	root_le.nr_blocks = cpu_to_le64(smm->ll.nr_blocks);
	root_le.nr_allocated = cpu_to_le64(smm->ll.nr_allocated);
	root_le.bitmap_root = cpu_to_le64(smm->ll.bitmap_root);
	root_le.ref_count_root = cpu_to_le64(smm->ll.ref_count_root);

	if (max < sizeof(root_le))
		return -ENOSPC;

	memcpy(where_le, &root_le, sizeof(root_le));

	return 0;
}

static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks);

static struct dm_space_map ops = {
	.destroy = sm_metadata_destroy,
	.extend = sm_metadata_extend,
	.get_nr_blocks = sm_metadata_get_nr_blocks,
	.get_nr_free = sm_metadata_get_nr_free,
	.get_count = sm_metadata_get_count,
	.count_is_more_than_one = sm_metadata_count_is_more_than_one,
	.set_count = sm_metadata_set_count,
	.inc_block = sm_metadata_inc_block,
	.dec_block = sm_metadata_dec_block,
	.new_block = sm_metadata_new_block,
	.commit = sm_metadata_commit,
	.root_size = sm_metadata_root_size,
	.copy_root = sm_metadata_copy_root,
	.register_threshold_callback = sm_metadata_register_threshold_callback
};

/*----------------------------------------------------------------*/

/*
 * When a new space map is created that manages its own space.  We use
 * this tiny bootstrap allocator.
 */
static void sm_bootstrap_destroy(struct dm_space_map *sm)
{
}

static int sm_bootstrap_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
{
	DMERR("bootstrap doesn't support extend");

	return -EINVAL;
}

static int sm_bootstrap_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
{
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);

	*count = smm->ll.nr_blocks;

	return 0;
}

static int sm_bootstrap_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
{
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);

	*count = smm->ll.nr_blocks - smm->begin;

	return 0;
}

static int sm_bootstrap_get_count(struct dm_space_map *sm, dm_block_t b,
				  uint32_t *result)
{
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);

	*result = (b < smm->begin) ? 1 : 0;

	return 0;
}

static int sm_bootstrap_count_is_more_than_one(struct dm_space_map *sm,
					       dm_block_t b, int *result)
{
	*result = 0;

	return 0;
}

static int sm_bootstrap_set_count(struct dm_space_map *sm, dm_block_t b,
				  uint32_t count)
{
	DMERR("bootstrap doesn't support set_count");

	return -EINVAL;
}

static int sm_bootstrap_new_block(struct dm_space_map *sm, dm_block_t *b)
{
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);

	/*
	 * We know the entire device is unused.
	 */
	if (smm->begin == smm->ll.nr_blocks)
		return -ENOSPC;

	*b = smm->begin++;

	return 0;
}

static int sm_bootstrap_inc_block(struct dm_space_map *sm, dm_block_t b)
{
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);

	return add_bop(smm, BOP_INC, b);
}

static int sm_bootstrap_dec_block(struct dm_space_map *sm, dm_block_t b)
{
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);

	return add_bop(smm, BOP_DEC, b);
}

static int sm_bootstrap_commit(struct dm_space_map *sm)
{
	return 0;
}

static int sm_bootstrap_root_size(struct dm_space_map *sm, size_t *result)
{
	DMERR("bootstrap doesn't support root_size");

	return -EINVAL;
}

static int sm_bootstrap_copy_root(struct dm_space_map *sm, void *where,
				  size_t max)
{
	DMERR("bootstrap doesn't support copy_root");

	return -EINVAL;
}

static struct dm_space_map bootstrap_ops = {
	.destroy = sm_bootstrap_destroy,
	.extend = sm_bootstrap_extend,
	.get_nr_blocks = sm_bootstrap_get_nr_blocks,
	.get_nr_free = sm_bootstrap_get_nr_free,
	.get_count = sm_bootstrap_get_count,
	.count_is_more_than_one = sm_bootstrap_count_is_more_than_one,
	.set_count = sm_bootstrap_set_count,
	.inc_block = sm_bootstrap_inc_block,
	.dec_block = sm_bootstrap_dec_block,
	.new_block = sm_bootstrap_new_block,
	.commit = sm_bootstrap_commit,
	.root_size = sm_bootstrap_root_size,
	.copy_root = sm_bootstrap_copy_root,
	.register_threshold_callback = NULL
};

/*----------------------------------------------------------------*/

static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
{
	int r, i;
	enum allocation_event ev;
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	dm_block_t old_len = smm->ll.nr_blocks;

	/*
	 * Flick into a mode where all blocks get allocated in the new area.
	 */
	smm->begin = old_len;
	memcpy(sm, &bootstrap_ops, sizeof(*sm));

	/*
	 * Extend.
	 */
	r = sm_ll_extend(&smm->ll, extra_blocks);
	if (r)
		goto out;

	/*
	 * We repeatedly increment then commit until the commit doesn't
	 * allocate any new blocks.
	 */
	do {
		for (i = old_len; !r && i < smm->begin; i++) {
			r = sm_ll_inc(&smm->ll, i, &ev);
			if (r)
				goto out;
		}
		old_len = smm->begin;

		r = sm_ll_commit(&smm->ll);
		if (r)
			goto out;

	} while (old_len != smm->begin);

out:
	/*
	 * Switch back to normal behaviour.
	 */
	memcpy(sm, &ops, sizeof(*sm));
	return r;
}

/*----------------------------------------------------------------*/

struct dm_space_map *dm_sm_metadata_init(void)
{
	struct sm_metadata *smm;

	smm = kmalloc(sizeof(*smm), GFP_KERNEL);
	if (!smm)
		return ERR_PTR(-ENOMEM);

	memcpy(&smm->sm, &ops, sizeof(smm->sm));

	return &smm->sm;
}

int dm_sm_metadata_create(struct dm_space_map *sm,
			  struct dm_transaction_manager *tm,
			  dm_block_t nr_blocks,
			  dm_block_t superblock)
{
	int r;
	dm_block_t i;
	enum allocation_event ev;
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);

	smm->begin = superblock + 1;
	smm->recursion_count = 0;
	smm->allocated_this_transaction = 0;
	brb_init(&smm->uncommitted);
	threshold_init(&smm->threshold);

	memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));

	r = sm_ll_new_metadata(&smm->ll, tm);
	if (r)
		return r;

	if (nr_blocks > DM_SM_METADATA_MAX_BLOCKS)
		nr_blocks = DM_SM_METADATA_MAX_BLOCKS;
	r = sm_ll_extend(&smm->ll, nr_blocks);
	if (r)
		return r;

	memcpy(&smm->sm, &ops, sizeof(smm->sm));

	/*
	 * Now we need to update the newly created data structures with the
	 * allocated blocks that they were built from.
	 */
	for (i = superblock; !r && i < smm->begin; i++)
		r = sm_ll_inc(&smm->ll, i, &ev);

	if (r)
		return r;

	return sm_metadata_commit(sm);
}

int dm_sm_metadata_open(struct dm_space_map *sm,
			struct dm_transaction_manager *tm,
			void *root_le, size_t len)
{
	int r;
	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);

	r = sm_ll_open_metadata(&smm->ll, tm, root_le, len);
	if (r)
		return r;

	smm->begin = 0;
	smm->recursion_count = 0;
	smm->allocated_this_transaction = 0;
	brb_init(&smm->uncommitted);
	threshold_init(&smm->threshold);

	memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
	return 0;
}
Commit	Line	Data
3241b1d3 JT	1	/*
	2	* Copyright (C) 2011 Red Hat, Inc.
	3	*
	4	* This file is released under the GPL.
	5	*/
	6
	7	#include "dm-space-map.h"
	8	#include "dm-space-map-common.h"
	9	#include "dm-space-map-metadata.h"
	10
	11	#include <linux/list.h>
	12	#include <linux/slab.h>
	13	#include <linux/device-mapper.h>
	14
	15	#define DM_MSG_PREFIX "space map metadata"
	16
	17	/----------------------------------------------------------------/
	18
2fc48021 JT	19	/*
	20	* An edge triggered threshold.
	21	*/
	22	struct threshold {
	23	bool threshold_set;
	24	bool value_set;
	25	dm_block_t threshold;
	26	dm_block_t current_value;
	27	dm_sm_threshold_fn fn;
	28	void *context;
	29	};
	30
	31	static void threshold_init(struct threshold *t)
	32	{
	33	t->threshold_set = false;
	34	t->value_set = false;
	35	}
	36
	37	static void set_threshold(struct threshold *t, dm_block_t value,
	38	dm_sm_threshold_fn fn, void *context)
	39	{
	40	t->threshold_set = true;
	41	t->threshold = value;
	42	t->fn = fn;
	43	t->context = context;
	44	}
	45
	46	static bool below_threshold(struct threshold *t, dm_block_t value)
	47	{
	48	return t->threshold_set && value <= t->threshold;
	49	}
	50
	51	static bool threshold_already_triggered(struct threshold *t)
	52	{
	53	return t->value_set && below_threshold(t, t->current_value);
	54	}
	55
	56	static void check_threshold(struct threshold *t, dm_block_t value)
	57	{
	58	if (below_threshold(t, value) &&
	59	!threshold_already_triggered(t))
	60	t->fn(t->context);
	61
	62	t->value_set = true;
	63	t->current_value = value;
	64	}
	65
	66	/----------------------------------------------------------------/
	67
3241b1d3 JT	68	/*
	69	* Space map interface.
	70	*
	71	* The low level disk format is written using the standard btree and
	72	* transaction manager. This means that performing disk operations may
	73	* cause us to recurse into the space map in order to allocate new blocks.
	74	* For this reason we have a pool of pre-allocated blocks large enough to
	75	* service any metadata_ll_disk operation.
	76	*/
	77
	78	/*
	79	* FIXME: we should calculate this based on the size of the device.
	80	* Only the metadata space map needs this functionality.
	81	*/
	82	#define MAX_RECURSIVE_ALLOCATIONS 1024
	83
	84	enum block_op_type {
	85	BOP_INC,
	86	BOP_DEC
	87	};
	88
	89	struct block_op {
	90	enum block_op_type type;
	91	dm_block_t block;
	92	};
	93
cebc2de4 JT	94	struct bop_ring_buffer {
	95	unsigned begin;
	96	unsigned end;
	97	struct block_op bops[MAX_RECURSIVE_ALLOCATIONS + 1];
	98	};
	99
	100	static void brb_init(struct bop_ring_buffer *brb)
	101	{
	102	brb->begin = 0;
	103	brb->end = 0;
	104	}
	105
	106	static bool brb_empty(struct bop_ring_buffer *brb)
	107	{
	108	return brb->begin == brb->end;
	109	}
	110
	111	static unsigned brb_next(struct bop_ring_buffer *brb, unsigned old)
	112	{
	113	unsigned r = old + 1;
	114	return (r >= (sizeof(brb->bops) / sizeof(*brb->bops))) ? 0 : r;
	115	}
	116
	117	static int brb_push(struct bop_ring_buffer *brb,
	118	enum block_op_type type, dm_block_t b)
	119	{
	120	struct block_op *bop;
	121	unsigned next = brb_next(brb, brb->end);
	122
	123	/*
	124	* We don't allow the last bop to be filled, this way we can
	125	* differentiate between full and empty.
	126	*/
	127	if (next == brb->begin)
	128	return -ENOMEM;
	129
	130	bop = brb->bops + brb->end;
	131	bop->type = type;
	132	bop->block = b;
	133
	134	brb->end = next;
	135
	136	return 0;
	137	}
	138
	139	static int brb_pop(struct bop_ring_buffer brb, struct block_op result)
	140	{
	141	struct block_op *bop;
	142
	143	if (brb_empty(brb))
	144	return -ENODATA;
	145
	146	bop = brb->bops + brb->begin;
	147	result->type = bop->type;
	148	result->block = bop->block;
	149
	150	brb->begin = brb_next(brb, brb->begin);
	151
	152	return 0;
	153	}
	154
	155	/----------------------------------------------------------------/
	156
3241b1d3 JT	157	struct sm_metadata {
	158	struct dm_space_map sm;
	159
	160	struct ll_disk ll;
	161	struct ll_disk old_ll;
	162
	163	dm_block_t begin;
	164
	165	unsigned recursion_count;
	166	unsigned allocated_this_transaction;
cebc2de4	167	struct bop_ring_buffer uncommitted;
2fc48021 JT	168
2fc48021 JT	169	struct threshold threshold;
3241b1d3 JT	170	};
	171
	172	static int add_bop(struct sm_metadata *smm, enum block_op_type type, dm_block_t b)
	173	{
cebc2de4	174	int r = brb_push(&smm->uncommitted, type, b);
3241b1d3	175
cebc2de4	176	if (r) {
3241b1d3 JT	177	DMERR("too many recursive allocations");
	178	return -ENOMEM;
	179	}
	180
3241b1d3 JT	181	return 0;
	182	}
	183
	184	static int commit_bop(struct sm_metadata smm, struct block_op op)
	185	{
	186	int r = 0;
	187	enum allocation_event ev;
	188
	189	switch (op->type) {
	190	case BOP_INC:
	191	r = sm_ll_inc(&smm->ll, op->block, &ev);
	192	break;
	193
	194	case BOP_DEC:
	195	r = sm_ll_dec(&smm->ll, op->block, &ev);
	196	break;
	197	}
	198
	199	return r;
	200	}
	201
	202	static void in(struct sm_metadata *smm)
	203	{
	204	smm->recursion_count++;
	205	}
	206
	207	static int out(struct sm_metadata *smm)
	208	{
	209	int r = 0;
	210
	211	/*
	212	* If we're not recursing then very bad things are happening.
	213	*/
	214	if (!smm->recursion_count) {
	215	DMERR("lost track of recursion depth");
	216	return -ENOMEM;
	217	}
	218
cebc2de4 JT	219	if (smm->recursion_count == 1) {
	220	while (!brb_empty(&smm->uncommitted)) {
	221	struct block_op bop;
	222
	223	r = brb_pop(&smm->uncommitted, &bop);
	224	if (r) {
	225	DMERR("bug in bop ring buffer");
	226	break;
	227	}
	228
	229	r = commit_bop(smm, &bop);
3241b1d3 JT	230	if (r)
	231	break;
	232	}
	233	}
	234
	235	smm->recursion_count--;
	236
	237	return r;
	238	}
	239
	240	/*
	241	* When using the out() function above, we often want to combine an error
	242	* code for the operation run in the recursive context with that from
	243	* out().
	244	*/
	245	static int combine_errors(int r1, int r2)
	246	{
	247	return r1 ? r1 : r2;
	248	}
	249
	250	static int recursing(struct sm_metadata *smm)
	251	{
	252	return smm->recursion_count;
	253	}
	254
	255	static void sm_metadata_destroy(struct dm_space_map *sm)
	256	{
	257	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	258
	259	kfree(smm);
	260	}
	261
3241b1d3 JT	262	static int sm_metadata_get_nr_blocks(struct dm_space_map sm, dm_block_t count)
	263	{
	264	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	265
	266	*count = smm->ll.nr_blocks;
	267
	268	return 0;
	269	}
	270
	271	static int sm_metadata_get_nr_free(struct dm_space_map sm, dm_block_t count)
	272	{
	273	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	274
	275	*count = smm->old_ll.nr_blocks - smm->old_ll.nr_allocated -
	276	smm->allocated_this_transaction;
	277
	278	return 0;
	279	}
	280
	281	static int sm_metadata_get_count(struct dm_space_map *sm, dm_block_t b,
	282	uint32_t *result)
	283	{
cebc2de4 JT	284	int r;
cebc2de4 JT	285	unsigned i;
3241b1d3 JT	286	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	287	unsigned adjustment = 0;
	288
	289	/*
	290	* We may have some uncommitted adjustments to add. This list
	291	* should always be really short.
	292	*/
cebc2de4 JT	293	for (i = smm->uncommitted.begin;
	294	i != smm->uncommitted.end;
	295	i = brb_next(&smm->uncommitted, i)) {
	296	struct block_op *op = smm->uncommitted.bops + i;
3241b1d3 JT	297
	298	if (op->block != b)
	299	continue;
	300
	301	switch (op->type) {
	302	case BOP_INC:
	303	adjustment++;
	304	break;
	305
	306	case BOP_DEC:
	307	adjustment--;
	308	break;
	309	}
	310	}
	311
	312	r = sm_ll_lookup(&smm->ll, b, result);
	313	if (r)
	314	return r;
	315
	316	*result += adjustment;
	317
	318	return 0;
	319	}
	320
	321	static int sm_metadata_count_is_more_than_one(struct dm_space_map *sm,
	322	dm_block_t b, int *result)
	323	{
cebc2de4 JT	324	int r, adjustment = 0;
cebc2de4 JT	325	unsigned i;
3241b1d3 JT	326	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	327	uint32_t rc;
	328
	329	/*
	330	* We may have some uncommitted adjustments to add. This list
	331	* should always be really short.
	332	*/
cebc2de4 JT	333	for (i = smm->uncommitted.begin;
	334	i != smm->uncommitted.end;
	335	i = brb_next(&smm->uncommitted, i)) {
	336
	337	struct block_op *op = smm->uncommitted.bops + i;
3241b1d3 JT	338
	339	if (op->block != b)
	340	continue;
	341
	342	switch (op->type) {
	343	case BOP_INC:
	344	adjustment++;
	345	break;
	346
	347	case BOP_DEC:
	348	adjustment--;
	349	break;
	350	}
	351	}
	352
	353	if (adjustment > 1) {
	354	*result = 1;
	355	return 0;
	356	}
	357
	358	r = sm_ll_lookup_bitmap(&smm->ll, b, &rc);
	359	if (r)
	360	return r;
	361
	362	if (rc == 3)
	363	/*
	364	* We err on the side of caution, and always return true.
	365	*/
	366	*result = 1;
	367	else
	368	*result = rc + adjustment > 1;
	369
	370	return 0;
	371	}
	372
	373	static int sm_metadata_set_count(struct dm_space_map *sm, dm_block_t b,
	374	uint32_t count)
	375	{
	376	int r, r2;
	377	enum allocation_event ev;
	378	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	379
	380	if (smm->recursion_count) {
	381	DMERR("cannot recurse set_count()");
	382	return -EINVAL;
	383	}
	384
	385	in(smm);
	386	r = sm_ll_insert(&smm->ll, b, count, &ev);
	387	r2 = out(smm);
	388
	389	return combine_errors(r, r2);
	390	}
	391
	392	static int sm_metadata_inc_block(struct dm_space_map *sm, dm_block_t b)
	393	{
	394	int r, r2 = 0;
	395	enum allocation_event ev;
	396	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	397
	398	if (recursing(smm))
	399	r = add_bop(smm, BOP_INC, b);
	400	else {
	401	in(smm);
402	r = sm_ll_inc(&smm->ll, b, &ev);
403	r2 = out(smm);
404	}
405
406	return combine_errors(r, r2);
407	}
408
409	static int sm_metadata_dec_block(struct dm_space_map *sm, dm_block_t b)
410	{
411	int r, r2 = 0;
412	enum allocation_event ev;
413	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
414
415	if (recursing(smm))
416	r = add_bop(smm, BOP_DEC, b);
417	else {
418	in(smm);
419	r = sm_ll_dec(&smm->ll, b, &ev);
420	r2 = out(smm);
421	}
422
423	return combine_errors(r, r2);
424	}
425
426	static int sm_metadata_new_block_(struct dm_space_map sm, dm_block_t b)
427	{
428	int r, r2 = 0;
429	enum allocation_event ev;
430	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
431
432	r = sm_ll_find_free_block(&smm->old_ll, smm->begin, smm->old_ll.nr_blocks, b);
433	if (r)
434	return r;
435
436	smm->begin = *b + 1;
437
438	if (recursing(smm))
439	r = add_bop(smm, BOP_INC, *b);
440	else {
441	in(smm);
442	r = sm_ll_inc(&smm->ll, *b, &ev);
443	r2 = out(smm);
444	}
445
446	if (!r)
447	smm->allocated_this_transaction++;
448
449	return combine_errors(r, r2);
450	}
451
452	static int sm_metadata_new_block(struct dm_space_map sm, dm_block_t b)
453	{
2fc48021 JT	454	dm_block_t count;
	455	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	456
3241b1d3	457	int r = sm_metadata_new_block_(sm, b);
f62b6b8f	458	if (r) {
c46985e2	459	DMERR_LIMIT("unable to allocate new metadata block");
f62b6b8f MS	460	return r;
f62b6b8f MS	461	}
2fc48021 JT	462
2fc48021 JT	463	r = sm_metadata_get_nr_free(sm, &count);
f62b6b8f	464	if (r) {
c46985e2	465	DMERR_LIMIT("couldn't get free block count");
f62b6b8f MS	466	return r;
f62b6b8f MS	467	}
2fc48021 JT	468
	469	check_threshold(&smm->threshold, count);
	470
3241b1d3 JT	471	return r;
	472	}
	473
	474	static int sm_metadata_commit(struct dm_space_map *sm)
	475	{
	476	int r;
	477	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	478
	479	r = sm_ll_commit(&smm->ll);
	480	if (r)
	481	return r;
	482
	483	memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
	484	smm->begin = 0;
	485	smm->allocated_this_transaction = 0;
	486
	487	return 0;
	488	}
	489
2fc48021 JT	490	static int sm_metadata_register_threshold_callback(struct dm_space_map *sm,
	491	dm_block_t threshold,
	492	dm_sm_threshold_fn fn,
	493	void *context)
	494	{
	495	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	496
	497	set_threshold(&smm->threshold, threshold, fn, context);
	498
	499	return 0;
	500	}
	501
3241b1d3 JT	502	static int sm_metadata_root_size(struct dm_space_map sm, size_t result)
	503	{
	504	*result = sizeof(struct disk_sm_root);
	505
	506	return 0;
	507	}
	508
	509	static int sm_metadata_copy_root(struct dm_space_map sm, void where_le, size_t max)
	510	{
	511	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	512	struct disk_sm_root root_le;
	513
	514	root_le.nr_blocks = cpu_to_le64(smm->ll.nr_blocks);
	515	root_le.nr_allocated = cpu_to_le64(smm->ll.nr_allocated);
	516	root_le.bitmap_root = cpu_to_le64(smm->ll.bitmap_root);
	517	root_le.ref_count_root = cpu_to_le64(smm->ll.ref_count_root);
	518
	519	if (max < sizeof(root_le))
	520	return -ENOSPC;
	521
	522	memcpy(where_le, &root_le, sizeof(root_le));
	523
	524	return 0;
	525	}
	526
1921c56d JT	527	static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks);
1921c56d JT	528
3241b1d3 JT	529	static struct dm_space_map ops = {
	530	.destroy = sm_metadata_destroy,
	531	.extend = sm_metadata_extend,
	532	.get_nr_blocks = sm_metadata_get_nr_blocks,
	533	.get_nr_free = sm_metadata_get_nr_free,
	534	.get_count = sm_metadata_get_count,
	535	.count_is_more_than_one = sm_metadata_count_is_more_than_one,
	536	.set_count = sm_metadata_set_count,
	537	.inc_block = sm_metadata_inc_block,
	538	.dec_block = sm_metadata_dec_block,
	539	.new_block = sm_metadata_new_block,
	540	.commit = sm_metadata_commit,
	541	.root_size = sm_metadata_root_size,
7c3d3f2a	542	.copy_root = sm_metadata_copy_root,
2fc48021	543	.register_threshold_callback = sm_metadata_register_threshold_callback
3241b1d3 JT	544	};
	545
	546	/----------------------------------------------------------------/
	547
	548	/*
	549	* When a new space map is created that manages its own space. We use
	550	* this tiny bootstrap allocator.
	551	*/
	552	static void sm_bootstrap_destroy(struct dm_space_map *sm)
	553	{
	554	}
	555
	556	static int sm_bootstrap_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
	557	{
88a488f6	558	DMERR("bootstrap doesn't support extend");
3241b1d3 JT	559
	560	return -EINVAL;
	561	}
	562
	563	static int sm_bootstrap_get_nr_blocks(struct dm_space_map sm, dm_block_t count)
	564	{
	565	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	566
c1c6156f DC	567	*count = smm->ll.nr_blocks;
	568
	569	return 0;
3241b1d3 JT	570	}
	571
	572	static int sm_bootstrap_get_nr_free(struct dm_space_map sm, dm_block_t count)
	573	{
	574	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	575
	576	*count = smm->ll.nr_blocks - smm->begin;
	577
	578	return 0;
	579	}
	580
	581	static int sm_bootstrap_get_count(struct dm_space_map *sm, dm_block_t b,
	582	uint32_t *result)
	583	{
	584	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	585
02717d98 JT	586	*result = (b < smm->begin) ? 1 : 0;
	587
	588	return 0;
3241b1d3 JT	589	}
	590
	591	static int sm_bootstrap_count_is_more_than_one(struct dm_space_map *sm,
	592	dm_block_t b, int *result)
	593	{
	594	*result = 0;
	595
	596	return 0;
	597	}
	598
	599	static int sm_bootstrap_set_count(struct dm_space_map *sm, dm_block_t b,
	600	uint32_t count)
	601	{
88a488f6	602	DMERR("bootstrap doesn't support set_count");
3241b1d3 JT	603
	604	return -EINVAL;
	605	}
	606
	607	static int sm_bootstrap_new_block(struct dm_space_map sm, dm_block_t b)
	608	{
	609	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	610
	611	/*
	612	* We know the entire device is unused.
	613	*/
	614	if (smm->begin == smm->ll.nr_blocks)
	615	return -ENOSPC;
	616
	617	*b = smm->begin++;
	618
	619	return 0;
	620	}
	621
	622	static int sm_bootstrap_inc_block(struct dm_space_map *sm, dm_block_t b)
	623	{
	624	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	625
	626	return add_bop(smm, BOP_INC, b);
	627	}
	628
	629	static int sm_bootstrap_dec_block(struct dm_space_map *sm, dm_block_t b)
	630	{
	631	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	632
	633	return add_bop(smm, BOP_DEC, b);
	634	}
	635
	636	static int sm_bootstrap_commit(struct dm_space_map *sm)
	637	{
	638	return 0;
	639	}
	640
	641	static int sm_bootstrap_root_size(struct dm_space_map sm, size_t result)
	642	{
88a488f6	643	DMERR("bootstrap doesn't support root_size");
3241b1d3 JT	644
	645	return -EINVAL;
	646	}
	647
	648	static int sm_bootstrap_copy_root(struct dm_space_map sm, void where,
	649	size_t max)
	650	{
88a488f6	651	DMERR("bootstrap doesn't support copy_root");
3241b1d3 JT	652
	653	return -EINVAL;
	654	}
	655
	656	static struct dm_space_map bootstrap_ops = {
	657	.destroy = sm_bootstrap_destroy,
	658	.extend = sm_bootstrap_extend,
	659	.get_nr_blocks = sm_bootstrap_get_nr_blocks,
	660	.get_nr_free = sm_bootstrap_get_nr_free,
	661	.get_count = sm_bootstrap_get_count,
	662	.count_is_more_than_one = sm_bootstrap_count_is_more_than_one,
	663	.set_count = sm_bootstrap_set_count,
	664	.inc_block = sm_bootstrap_inc_block,
	665	.dec_block = sm_bootstrap_dec_block,
	666	.new_block = sm_bootstrap_new_block,
	667	.commit = sm_bootstrap_commit,
	668	.root_size = sm_bootstrap_root_size,
7c3d3f2a JT	669	.copy_root = sm_bootstrap_copy_root,
7c3d3f2a JT	670	.register_threshold_callback = NULL
3241b1d3 JT	671	};
	672
	673	/----------------------------------------------------------------/
	674
1921c56d JT	675	static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
	676	{
	677	int r, i;
	678	enum allocation_event ev;
	679	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	680	dm_block_t old_len = smm->ll.nr_blocks;
	681
	682	/*
	683	* Flick into a mode where all blocks get allocated in the new area.
	684	*/
	685	smm->begin = old_len;
7e664b3d	686	memcpy(sm, &bootstrap_ops, sizeof(*sm));
1921c56d JT	687
	688	/*
	689	* Extend.
	690	*/
	691	r = sm_ll_extend(&smm->ll, extra_blocks);
7e664b3d JT	692	if (r)
	693	goto out;
	694
fca02843 JT	695	/*
	696	* We repeatedly increment then commit until the commit doesn't
	697	* allocate any new blocks.
	698	*/
	699	do {
	700	for (i = old_len; !r && i < smm->begin; i++) {
	701	r = sm_ll_inc(&smm->ll, i, &ev);
	702	if (r)
	703	goto out;
	704	}
	705	old_len = smm->begin;
	706
	707	r = sm_ll_commit(&smm->ll);
7e664b3d JT	708	if (r)
7e664b3d JT	709	goto out;
1921c56d	710
fca02843	711	} while (old_len != smm->begin);
7e664b3d JT	712
7e664b3d JT	713	out:
1921c56d JT	714	/*
	715	* Switch back to normal behaviour.
	716	*/
7e664b3d	717	memcpy(sm, &ops, sizeof(*sm));
1921c56d JT	718	return r;
	719	}
	720
	721	/----------------------------------------------------------------/
	722
3241b1d3 JT	723	struct dm_space_map *dm_sm_metadata_init(void)
	724	{
	725	struct sm_metadata *smm;
	726
	727	smm = kmalloc(sizeof(*smm), GFP_KERNEL);
	728	if (!smm)
	729	return ERR_PTR(-ENOMEM);
	730
	731	memcpy(&smm->sm, &ops, sizeof(smm->sm));
	732
	733	return &smm->sm;
	734	}
	735
	736	int dm_sm_metadata_create(struct dm_space_map *sm,
	737	struct dm_transaction_manager *tm,
	738	dm_block_t nr_blocks,
	739	dm_block_t superblock)
	740	{
	741	int r;
	742	dm_block_t i;
	743	enum allocation_event ev;
	744	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	745
	746	smm->begin = superblock + 1;
	747	smm->recursion_count = 0;
	748	smm->allocated_this_transaction = 0;
cebc2de4	749	brb_init(&smm->uncommitted);
2fc48021	750	threshold_init(&smm->threshold);
3241b1d3 JT	751
	752	memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
	753
	754	r = sm_ll_new_metadata(&smm->ll, tm);
	755	if (r)
	756	return r;
	757
7d48935e MS	758	if (nr_blocks > DM_SM_METADATA_MAX_BLOCKS)
7d48935e MS	759	nr_blocks = DM_SM_METADATA_MAX_BLOCKS;
3241b1d3 JT	760	r = sm_ll_extend(&smm->ll, nr_blocks);
	761	if (r)
	762	return r;
	763
	764	memcpy(&smm->sm, &ops, sizeof(smm->sm));
	765
	766	/*
	767	* Now we need to update the newly created data structures with the
	768	* allocated blocks that they were built from.
	769	*/
	770	for (i = superblock; !r && i < smm->begin; i++)
	771	r = sm_ll_inc(&smm->ll, i, &ev);
	772
	773	if (r)
	774	return r;
	775
	776	return sm_metadata_commit(sm);
	777	}
	778
	779	int dm_sm_metadata_open(struct dm_space_map *sm,
	780	struct dm_transaction_manager *tm,
	781	void *root_le, size_t len)
	782	{
	783	int r;
	784	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
	785
	786	r = sm_ll_open_metadata(&smm->ll, tm, root_le, len);
	787	if (r)
	788	return r;
	789
	790	smm->begin = 0;
	791	smm->recursion_count = 0;
	792	smm->allocated_this_transaction = 0;
cebc2de4	793	brb_init(&smm->uncommitted);
2fc48021	794	threshold_init(&smm->threshold);
3241b1d3 JT	795
	796	memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
	797	return 0;
	798	}