drivers/md/persistent-data/dm-btree-spine.c

Source file repositories/reference/linux-study-clean/drivers/md/persistent-data/dm-btree-spine.c

File Facts

System
Linux kernel
Corpus path
drivers/md/persistent-data/dm-btree-spine.c
Extension
.c
Size
5795 bytes
Lines
264
Domain
Driver Families
Bucket
drivers/md
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2011 Red Hat, Inc.
 *
 * This file is released under the GPL.
 */

#include "dm-btree-internal.h"
#include "dm-transaction-manager.h"

#include <linux/device-mapper.h>

#define DM_MSG_PREFIX "btree spine"

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

#define BTREE_CSUM_XOR 121107

static void node_prepare_for_write(const struct dm_block_validator *v,
				   struct dm_block *b,
				   size_t block_size)
{
	struct btree_node *n = dm_block_data(b);
	struct node_header *h = &n->header;

	h->blocknr = cpu_to_le64(dm_block_location(b));
	h->csum = cpu_to_le32(dm_bm_checksum(&h->flags,
					     block_size - sizeof(__le32),
					     BTREE_CSUM_XOR));
}

static int node_check(const struct dm_block_validator *v,
		      struct dm_block *b,
		      size_t block_size)
{
	struct btree_node *n = dm_block_data(b);
	struct node_header *h = &n->header;
	size_t value_size;
	__le32 csum_disk;
	uint32_t flags, nr_entries, max_entries;

	if (dm_block_location(b) != le64_to_cpu(h->blocknr)) {
		DMERR_LIMIT("%s failed: blocknr %llu != wanted %llu", __func__,
			    le64_to_cpu(h->blocknr), dm_block_location(b));
		return -ENOTBLK;
	}

	csum_disk = cpu_to_le32(dm_bm_checksum(&h->flags,
					       block_size - sizeof(__le32),
					       BTREE_CSUM_XOR));
	if (csum_disk != h->csum) {
		DMERR_LIMIT("%s failed: csum %u != wanted %u", __func__,
			    le32_to_cpu(csum_disk), le32_to_cpu(h->csum));
		return -EILSEQ;
	}

	nr_entries = le32_to_cpu(h->nr_entries);
	max_entries = le32_to_cpu(h->max_entries);
	value_size = le32_to_cpu(h->value_size);

	if (sizeof(struct node_header) +
	    (sizeof(__le64) + value_size) * max_entries > block_size) {
		DMERR_LIMIT("%s failed: max_entries too large", __func__);
		return -EILSEQ;
	}

	if (nr_entries > max_entries) {
		DMERR_LIMIT("%s failed: too many entries", __func__);
		return -EILSEQ;
	}

	/*
	 * The node must be either INTERNAL or LEAF.
	 */
	flags = le32_to_cpu(h->flags);
	if (!(flags & INTERNAL_NODE) && !(flags & LEAF_NODE)) {
		DMERR_LIMIT("%s failed: node is neither INTERNAL or LEAF", __func__);
		return -EILSEQ;
	}

	return 0;
}

const struct dm_block_validator btree_node_validator = {
	.name = "btree_node",
	.prepare_for_write = node_prepare_for_write,
	.check = node_check
};

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

Annotation

Implementation Notes