drivers/md/dm-integrity.c

/*
 * Copyright (C) 2016-2017 Red Hat, Inc. All rights reserved.
 * Copyright (C) 2016-2017 Milan Broz
 * Copyright (C) 2016-2017 Mikulas Patocka
 *
 * This file is released under the GPL.
 */

#include "dm-bio-record.h"

#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/device-mapper.h>
#include <linux/dm-io.h>
#include <linux/vmalloc.h>
#include <linux/sort.h>
#include <linux/rbtree.h>
#include <linux/delay.h>
#include <linux/random.h>
#include <linux/reboot.h>
#include <crypto/hash.h>
#include <crypto/skcipher.h>
#include <linux/async_tx.h>
#include <linux/dm-bufio.h>

#include "dm-audit.h"

#define DM_MSG_PREFIX "integrity"

#define DEFAULT_INTERLEAVE_SECTORS	32768
#define DEFAULT_JOURNAL_SIZE_FACTOR	7
#define DEFAULT_SECTORS_PER_BITMAP_BIT	32768
#define DEFAULT_BUFFER_SECTORS		128
#define DEFAULT_JOURNAL_WATERMARK	50
#define DEFAULT_SYNC_MSEC		10000
#define DEFAULT_MAX_JOURNAL_SECTORS	131072
#define MIN_LOG2_INTERLEAVE_SECTORS	3
#define MAX_LOG2_INTERLEAVE_SECTORS	31
#define METADATA_WORKQUEUE_MAX_ACTIVE	16
#define RECALC_SECTORS			32768
#define RECALC_WRITE_SUPER		16
#define BITMAP_BLOCK_SIZE		4096	/* don't change it */
#define BITMAP_FLUSH_INTERVAL		(10 * HZ)
#define DISCARD_FILLER			0xf6
#define SALT_SIZE			16

/*
 * Warning - DEBUG_PRINT prints security-sensitive data to the log,
 * so it should not be enabled in the official kernel
 */
//#define DEBUG_PRINT
//#define INTERNAL_VERIFY

/*
 * On disk structures
 */

#define SB_MAGIC			"integrt"
#define SB_VERSION_1			1
#define SB_VERSION_2			2
#define SB_VERSION_3			3
#define SB_VERSION_4			4
#define SB_VERSION_5			5
#define SB_SECTORS			8
#define MAX_SECTORS_PER_BLOCK		8

struct superblock {
	__u8 magic[8];
	__u8 version;
	__u8 log2_interleave_sectors;
	__le16 integrity_tag_size;
	__le32 journal_sections;
	__le64 provided_data_sectors;	/* userspace uses this value */
	__le32 flags;
	__u8 log2_sectors_per_block;
	__u8 log2_blocks_per_bitmap_bit;
	__u8 pad[2];
	__le64 recalc_sector;
	__u8 pad2[8];
	__u8 salt[SALT_SIZE];
};

#define SB_FLAG_HAVE_JOURNAL_MAC	0x1
#define SB_FLAG_RECALCULATING		0x2
#define SB_FLAG_DIRTY_BITMAP		0x4
#define SB_FLAG_FIXED_PADDING		0x8
#define SB_FLAG_FIXED_HMAC		0x10

#define	JOURNAL_ENTRY_ROUNDUP		8

typedef __le64 commit_id_t;
#define JOURNAL_MAC_PER_SECTOR		8

struct journal_entry {
	union {
		struct {
			__le32 sector_lo;
			__le32 sector_hi;
		} s;
		__le64 sector;
	} u;
	commit_id_t last_bytes[];
	/* __u8 tag[0]; */
};

#define journal_entry_tag(ic, je)		((__u8 *)&(je)->last_bytes[(ic)->sectors_per_block])

#if BITS_PER_LONG == 64
#define journal_entry_set_sector(je, x)		do { smp_wmb(); WRITE_ONCE((je)->u.sector, cpu_to_le64(x)); } while (0)
#else
#define journal_entry_set_sector(je, x)		do { (je)->u.s.sector_lo = cpu_to_le32(x); smp_wmb(); WRITE_ONCE((je)->u.s.sector_hi, cpu_to_le32((x) >> 32)); } while (0)
#endif
#define journal_entry_get_sector(je)		le64_to_cpu((je)->u.sector)
#define journal_entry_is_unused(je)		((je)->u.s.sector_hi == cpu_to_le32(-1))
#define journal_entry_set_unused(je)		do { ((je)->u.s.sector_hi = cpu_to_le32(-1)); } while (0)
#define journal_entry_is_inprogress(je)		((je)->u.s.sector_hi == cpu_to_le32(-2))
#define journal_entry_set_inprogress(je)	do { ((je)->u.s.sector_hi = cpu_to_le32(-2)); } while (0)

#define JOURNAL_BLOCK_SECTORS		8
#define JOURNAL_SECTOR_DATA		((1 << SECTOR_SHIFT) - sizeof(commit_id_t))
#define JOURNAL_MAC_SIZE		(JOURNAL_MAC_PER_SECTOR * JOURNAL_BLOCK_SECTORS)

struct journal_sector {
	__u8 entries[JOURNAL_SECTOR_DATA - JOURNAL_MAC_PER_SECTOR];
	__u8 mac[JOURNAL_MAC_PER_SECTOR];
	commit_id_t commit_id;
};

#define MAX_TAG_SIZE			(JOURNAL_SECTOR_DATA - JOURNAL_MAC_PER_SECTOR - offsetof(struct journal_entry, last_bytes[MAX_SECTORS_PER_BLOCK]))

#define METADATA_PADDING_SECTORS	8

#define N_COMMIT_IDS			4

static unsigned char prev_commit_seq(unsigned char seq)
{
	return (seq + N_COMMIT_IDS - 1) % N_COMMIT_IDS;
}

static unsigned char next_commit_seq(unsigned char seq)
{
	return (seq + 1) % N_COMMIT_IDS;
}

/*
 * In-memory structures
 */

struct journal_node {
	struct rb_node node;
	sector_t sector;
};

struct alg_spec {
	char *alg_string;
	char *key_string;
	__u8 *key;
	unsigned key_size;
};

struct dm_integrity_c {
	struct dm_dev *dev;
	struct dm_dev *meta_dev;
	unsigned tag_size;
	__s8 log2_tag_size;
	sector_t start;
	mempool_t journal_io_mempool;
	struct dm_io_client *io;
	struct dm_bufio_client *bufio;
	struct workqueue_struct *metadata_wq;
	struct superblock *sb;
	unsigned journal_pages;
	unsigned n_bitmap_blocks;

	struct page_list *journal;
	struct page_list *journal_io;
	struct page_list *journal_xor;
	struct page_list *recalc_bitmap;
	struct page_list *may_write_bitmap;
	struct bitmap_block_status *bbs;
	unsigned bitmap_flush_interval;
	int synchronous_mode;
	struct bio_list synchronous_bios;
	struct delayed_work bitmap_flush_work;

	struct crypto_skcipher *journal_crypt;
	struct scatterlist **journal_scatterlist;
	struct scatterlist **journal_io_scatterlist;
	struct skcipher_request **sk_requests;

	struct crypto_shash *journal_mac;

	struct journal_node *journal_tree;
	struct rb_root journal_tree_root;

	sector_t provided_data_sectors;

	unsigned short journal_entry_size;
	unsigned char journal_entries_per_sector;
	unsigned char journal_section_entries;
	unsigned short journal_section_sectors;
	unsigned journal_sections;
	unsigned journal_entries;
	sector_t data_device_sectors;
	sector_t meta_device_sectors;
	unsigned initial_sectors;
	unsigned metadata_run;
	__s8 log2_metadata_run;
	__u8 log2_buffer_sectors;
	__u8 sectors_per_block;
	__u8 log2_blocks_per_bitmap_bit;

	unsigned char mode;

	int failed;

	struct crypto_shash *internal_hash;

	struct dm_target *ti;

	/* these variables are locked with endio_wait.lock */
	struct rb_root in_progress;
	struct list_head wait_list;
	wait_queue_head_t endio_wait;
	struct workqueue_struct *wait_wq;
	struct workqueue_struct *offload_wq;

	unsigned char commit_seq;
	commit_id_t commit_ids[N_COMMIT_IDS];

	unsigned committed_section;
	unsigned n_committed_sections;

	unsigned uncommitted_section;
	unsigned n_uncommitted_sections;

	unsigned free_section;
	unsigned char free_section_entry;
	unsigned free_sectors;

	unsigned free_sectors_threshold;

	struct workqueue_struct *commit_wq;
	struct work_struct commit_work;

	struct workqueue_struct *writer_wq;
	struct work_struct writer_work;

	struct workqueue_struct *recalc_wq;
	struct work_struct recalc_work;
	u8 *recalc_buffer;
	u8 *recalc_tags;

	struct bio_list flush_bio_list;

	unsigned long autocommit_jiffies;
	struct timer_list autocommit_timer;
	unsigned autocommit_msec;

	wait_queue_head_t copy_to_journal_wait;

	struct completion crypto_backoff;

	bool journal_uptodate;
	bool just_formatted;
	bool recalculate_flag;
	bool reset_recalculate_flag;
	bool discard;
	bool fix_padding;
	bool fix_hmac;
	bool legacy_recalculate;

	struct alg_spec internal_hash_alg;
	struct alg_spec journal_crypt_alg;
	struct alg_spec journal_mac_alg;

	atomic64_t number_of_mismatches;

	struct notifier_block reboot_notifier;
};

struct dm_integrity_range {
	sector_t logical_sector;
	sector_t n_sectors;
	bool waiting;
	union {
		struct rb_node node;
		struct {
			struct task_struct *task;
			struct list_head wait_entry;
		};
	};
};

struct dm_integrity_io {
	struct work_struct work;

	struct dm_integrity_c *ic;
	enum req_opf op;
	bool fua;

	struct dm_integrity_range range;

	sector_t metadata_block;
	unsigned metadata_offset;

	atomic_t in_flight;
	blk_status_t bi_status;

	struct completion *completion;

	struct dm_bio_details bio_details;
};

struct journal_completion {
	struct dm_integrity_c *ic;
	atomic_t in_flight;
	struct completion comp;
};

struct journal_io {
	struct dm_integrity_range range;
	struct journal_completion *comp;
};

struct bitmap_block_status {
	struct work_struct work;
	struct dm_integrity_c *ic;
	unsigned idx;
	unsigned long *bitmap;
	struct bio_list bio_queue;
	spinlock_t bio_queue_lock;

};

static struct kmem_cache *journal_io_cache;

#define JOURNAL_IO_MEMPOOL	32

#ifdef DEBUG_PRINT
#define DEBUG_print(x, ...)	printk(KERN_DEBUG x, ##__VA_ARGS__)
static void __DEBUG_bytes(__u8 *bytes, size_t len, const char *msg, ...)
{
	va_list args;
	va_start(args, msg);
	vprintk(msg, args);
	va_end(args);
	if (len)
		pr_cont(":");
	while (len) {
		pr_cont(" %02x", *bytes);
		bytes++;
		len--;
	}
	pr_cont("\n");
}
#define DEBUG_bytes(bytes, len, msg, ...)	__DEBUG_bytes(bytes, len, KERN_DEBUG msg, ##__VA_ARGS__)
#else
#define DEBUG_print(x, ...)			do { } while (0)
#define DEBUG_bytes(bytes, len, msg, ...)	do { } while (0)
#endif

static void dm_integrity_prepare(struct request *rq)
{
}

static void dm_integrity_complete(struct request *rq, unsigned int nr_bytes)
{
}

/*
 * DM Integrity profile, protection is performed layer above (dm-crypt)
 */
static const struct blk_integrity_profile dm_integrity_profile = {
	.name			= "DM-DIF-EXT-TAG",
	.generate_fn		= NULL,
	.verify_fn		= NULL,
	.prepare_fn		= dm_integrity_prepare,
	.complete_fn		= dm_integrity_complete,
};

static void dm_integrity_map_continue(struct dm_integrity_io *dio, bool from_map);
static void integrity_bio_wait(struct work_struct *w);
static void dm_integrity_dtr(struct dm_target *ti);

static void dm_integrity_io_error(struct dm_integrity_c *ic, const char *msg, int err)
{
	if (err == -EILSEQ)
		atomic64_inc(&ic->number_of_mismatches);
	if (!cmpxchg(&ic->failed, 0, err))
		DMERR("Error on %s: %d", msg, err);
}

static int dm_integrity_failed(struct dm_integrity_c *ic)
{
	return READ_ONCE(ic->failed);
}

static bool dm_integrity_disable_recalculate(struct dm_integrity_c *ic)
{
	if (ic->legacy_recalculate)
		return false;
	if (!(ic->sb->flags & cpu_to_le32(SB_FLAG_FIXED_HMAC)) ?
	    ic->internal_hash_alg.key || ic->journal_mac_alg.key :
	    ic->internal_hash_alg.key && !ic->journal_mac_alg.key)
		return true;
	return false;
}

static commit_id_t dm_integrity_commit_id(struct dm_integrity_c *ic, unsigned i,
					  unsigned j, unsigned char seq)
{
	/*
	 * Xor the number with section and sector, so that if a piece of
	 * journal is written at wrong place, it is detected.
	 */
	return ic->commit_ids[seq] ^ cpu_to_le64(((__u64)i << 32) ^ j);
}

static void get_area_and_offset(struct dm_integrity_c *ic, sector_t data_sector,
				sector_t *area, sector_t *offset)
{
	if (!ic->meta_dev) {
		__u8 log2_interleave_sectors = ic->sb->log2_interleave_sectors;
		*area = data_sector >> log2_interleave_sectors;
		*offset = (unsigned)data_sector & ((1U << log2_interleave_sectors) - 1);
	} else {
		*area = 0;
		*offset = data_sector;
	}
}

#define sector_to_block(ic, n)						\
do {									\
	BUG_ON((n) & (unsigned)((ic)->sectors_per_block - 1));		\
	(n) >>= (ic)->sb->log2_sectors_per_block;			\
} while (0)

static __u64 get_metadata_sector_and_offset(struct dm_integrity_c *ic, sector_t area,
					    sector_t offset, unsigned *metadata_offset)
{
	__u64 ms;
	unsigned mo;

	ms = area << ic->sb->log2_interleave_sectors;
	if (likely(ic->log2_metadata_run >= 0))
		ms += area << ic->log2_metadata_run;
	else
		ms += area * ic->metadata_run;
	ms >>= ic->log2_buffer_sectors;

	sector_to_block(ic, offset);

	if (likely(ic->log2_tag_size >= 0)) {
		ms += offset >> (SECTOR_SHIFT + ic->log2_buffer_sectors - ic->log2_tag_size);
		mo = (offset << ic->log2_tag_size) & ((1U << SECTOR_SHIFT << ic->log2_buffer_sectors) - 1);
	} else {
		ms += (__u64)offset * ic->tag_size >> (SECTOR_SHIFT + ic->log2_buffer_sectors);
		mo = (offset * ic->tag_size) & ((1U << SECTOR_SHIFT << ic->log2_buffer_sectors) - 1);
	}
	*metadata_offset = mo;
	return ms;
}

static sector_t get_data_sector(struct dm_integrity_c *ic, sector_t area, sector_t offset)
{
	sector_t result;

	if (ic->meta_dev)
		return offset;

	result = area << ic->sb->log2_interleave_sectors;
	if (likely(ic->log2_metadata_run >= 0))
		result += (area + 1) << ic->log2_metadata_run;
	else
		result += (area + 1) * ic->metadata_run;

	result += (sector_t)ic->initial_sectors + offset;
	result += ic->start;

	return result;
}

static void wraparound_section(struct dm_integrity_c *ic, unsigned *sec_ptr)
{
	if (unlikely(*sec_ptr >= ic->journal_sections))
		*sec_ptr -= ic->journal_sections;
}

static void sb_set_version(struct dm_integrity_c *ic)
{
	if (ic->sb->flags & cpu_to_le32(SB_FLAG_FIXED_HMAC))
		ic->sb->version = SB_VERSION_5;
	else if (ic->sb->flags & cpu_to_le32(SB_FLAG_FIXED_PADDING))
		ic->sb->version = SB_VERSION_4;
	else if (ic->mode == 'B' || ic->sb->flags & cpu_to_le32(SB_FLAG_DIRTY_BITMAP))
		ic->sb->version = SB_VERSION_3;
	else if (ic->meta_dev || ic->sb->flags & cpu_to_le32(SB_FLAG_RECALCULATING))
		ic->sb->version = SB_VERSION_2;
	else
		ic->sb->version = SB_VERSION_1;
}

static int sb_mac(struct dm_integrity_c *ic, bool wr)
{
	SHASH_DESC_ON_STACK(desc, ic->journal_mac);
	int r;
	unsigned size = crypto_shash_digestsize(ic->journal_mac);

	if (sizeof(struct superblock) + size > 1 << SECTOR_SHIFT) {
		dm_integrity_io_error(ic, "digest is too long", -EINVAL);
		return -EINVAL;
	}

	desc->tfm = ic->journal_mac;

	r = crypto_shash_init(desc);
	if (unlikely(r < 0)) {
		dm_integrity_io_error(ic, "crypto_shash_init", r);
		return r;
	}

	r = crypto_shash_update(desc, (__u8 *)ic->sb, (1 << SECTOR_SHIFT) - size);
	if (unlikely(r < 0)) {
		dm_integrity_io_error(ic, "crypto_shash_update", r);
		return r;
	}

	if (likely(wr)) {
		r = crypto_shash_final(desc, (__u8 *)ic->sb + (1 << SECTOR_SHIFT) - size);
		if (unlikely(r < 0)) {
			dm_integrity_io_error(ic, "crypto_shash_final", r);
			return r;
		}
	} else {
		__u8 result[HASH_MAX_DIGESTSIZE];
		r = crypto_shash_final(desc, result);
		if (unlikely(r < 0)) {
			dm_integrity_io_error(ic, "crypto_shash_final", r);
			return r;
		}
		if (memcmp((__u8 *)ic->sb + (1 << SECTOR_SHIFT) - size, result, size)) {
			dm_integrity_io_error(ic, "superblock mac", -EILSEQ);
			dm_audit_log_target(DM_MSG_PREFIX, "mac-superblock", ic->ti, 0);
			return -EILSEQ;
		}
	}

	return 0;
}

static int sync_rw_sb(struct dm_integrity_c *ic, int op, int op_flags)
{
	struct dm_io_request io_req;
	struct dm_io_region io_loc;
	int r;

	io_req.bi_op = op;
	io_req.bi_op_flags = op_flags;
	io_req.mem.type = DM_IO_KMEM;
	io_req.mem.ptr.addr = ic->sb;
	io_req.notify.fn = NULL;
	io_req.client = ic->io;
	io_loc.bdev = ic->meta_dev ? ic->meta_dev->bdev : ic->dev->bdev;
	io_loc.sector = ic->start;
	io_loc.count = SB_SECTORS;

	if (op == REQ_OP_WRITE) {
		sb_set_version(ic);
		if (ic->journal_mac && ic->sb->flags & cpu_to_le32(SB_FLAG_FIXED_HMAC)) {
			r = sb_mac(ic, true);
			if (unlikely(r))
				return r;
		}
	}

	r = dm_io(&io_req, 1, &io_loc, NULL);
	if (unlikely(r))
		return r;

	if (op == REQ_OP_READ) {
		if (ic->mode != 'R' && ic->journal_mac && ic->sb->flags & cpu_to_le32(SB_FLAG_FIXED_HMAC)) {
			r = sb_mac(ic, false);
			if (unlikely(r))
				return r;
		}
	}

	return 0;
}

#define BITMAP_OP_TEST_ALL_SET		0
#define BITMAP_OP_TEST_ALL_CLEAR	1
#define BITMAP_OP_SET			2
#define BITMAP_OP_CLEAR			3

static bool block_bitmap_op(struct dm_integrity_c *ic, struct page_list *bitmap,
			    sector_t sector, sector_t n_sectors, int mode)
{
	unsigned long bit, end_bit, this_end_bit, page, end_page;
	unsigned long *data;

	if (unlikely(((sector | n_sectors) & ((1 << ic->sb->log2_sectors_per_block) - 1)) != 0)) {
		DMCRIT("invalid bitmap access (%llx,%llx,%d,%d,%d)",
			sector,
			n_sectors,
			ic->sb->log2_sectors_per_block,
			ic->log2_blocks_per_bitmap_bit,
			mode);
		BUG();
	}

	if (unlikely(!n_sectors))
		return true;

	bit = sector >> (ic->sb->log2_sectors_per_block + ic->log2_blocks_per_bitmap_bit);
	end_bit = (sector + n_sectors - 1) >>
		(ic->sb->log2_sectors_per_block + ic->log2_blocks_per_bitmap_bit);

	page = bit / (PAGE_SIZE * 8);
	bit %= PAGE_SIZE * 8;

	end_page = end_bit / (PAGE_SIZE * 8);
	end_bit %= PAGE_SIZE * 8;

repeat:
	if (page < end_page) {
		this_end_bit = PAGE_SIZE * 8 - 1;
	} else {
		this_end_bit = end_bit;
	}

	data = lowmem_page_address(bitmap[page].page);

	if (mode == BITMAP_OP_TEST_ALL_SET) {
		while (bit <= this_end_bit) {
			if (!(bit % BITS_PER_LONG) && this_end_bit >= bit + BITS_PER_LONG - 1) {
				do {
					if (data[bit / BITS_PER_LONG] != -1)
						return false;
					bit += BITS_PER_LONG;
				} while (this_end_bit >= bit + BITS_PER_LONG - 1);
				continue;
			}
			if (!test_bit(bit, data))
				return false;
			bit++;
		}
	} else if (mode == BITMAP_OP_TEST_ALL_CLEAR) {
		while (bit <= this_end_bit) {
			if (!(bit % BITS_PER_LONG) && this_end_bit >= bit + BITS_PER_LONG - 1) {
				do {
					if (data[bit / BITS_PER_LONG] != 0)
						return false;
					bit += BITS_PER_LONG;
				} while (this_end_bit >= bit + BITS_PER_LONG - 1);
				continue;
			}
			if (test_bit(bit, data))
				return false;
			bit++;
		}
	} else if (mode == BITMAP_OP_SET) {
		while (bit <= this_end_bit) {
			if (!(bit % BITS_PER_LONG) && this_end_bit >= bit + BITS_PER_LONG - 1) {
				do {
					data[bit / BITS_PER_LONG] = -1;
					bit += BITS_PER_LONG;
				} while (this_end_bit >= bit + BITS_PER_LONG - 1);
				continue;
			}
			__set_bit(bit, data);
			bit++;
		}
	} else if (mode == BITMAP_OP_CLEAR) {
		if (!bit && this_end_bit == PAGE_SIZE * 8 - 1)
			clear_page(data);
		else while (bit <= this_end_bit) {
			if (!(bit % BITS_PER_LONG) && this_end_bit >= bit + BITS_PER_LONG - 1) {
				do {
					data[bit / BITS_PER_LONG] = 0;
					bit += BITS_PER_LONG;
				} while (this_end_bit >= bit + BITS_PER_LONG - 1);
				continue;
			}
			__clear_bit(bit, data);
			bit++;
		}
	} else {
		BUG();
	}

	if (unlikely(page < end_page)) {
		bit = 0;
		page++;
		goto repeat;
	}

	return true;
}

static void block_bitmap_copy(struct dm_integrity_c *ic, struct page_list *dst, struct page_list *src)
{
	unsigned n_bitmap_pages = DIV_ROUND_UP(ic->n_bitmap_blocks, PAGE_SIZE / BITMAP_BLOCK_SIZE);
	unsigned i;

	for (i = 0; i < n_bitmap_pages; i++) {
		unsigned long *dst_data = lowmem_page_address(dst[i].page);
		unsigned long *src_data = lowmem_page_address(src[i].page);
		copy_page(dst_data, src_data);
	}
}

static struct bitmap_block_status *sector_to_bitmap_block(struct dm_integrity_c *ic, sector_t sector)
{
	unsigned bit = sector >> (ic->sb->log2_sectors_per_block + ic->log2_blocks_per_bitmap_bit);
	unsigned bitmap_block = bit / (BITMAP_BLOCK_SIZE * 8);

	BUG_ON(bitmap_block >= ic->n_bitmap_blocks);
	return &ic->bbs[bitmap_block];
}

static void access_journal_check(struct dm_integrity_c *ic, unsigned section, unsigned offset,
				 bool e, const char *function)
{
#if defined(CONFIG_DM_DEBUG) || defined(INTERNAL_VERIFY)
	unsigned limit = e ? ic->journal_section_entries : ic->journal_section_sectors;

	if (unlikely(section >= ic->journal_sections) ||
	    unlikely(offset >= limit)) {
		DMCRIT("%s: invalid access at (%u,%u), limit (%u,%u)",
		       function, section, offset, ic->journal_sections, limit);
		BUG();
	}
#endif
}

static void page_list_location(struct dm_integrity_c *ic, unsigned section, unsigned offset,
			       unsigned *pl_index, unsigned *pl_offset)
{
	unsigned sector;

	access_journal_check(ic, section, offset, false, "page_list_location");

	sector = section * ic->journal_section_sectors + offset;

	*pl_index = sector >> (PAGE_SHIFT - SECTOR_SHIFT);
	*pl_offset = (sector << SECTOR_SHIFT) & (PAGE_SIZE - 1);
}

static struct journal_sector *access_page_list(struct dm_integrity_c *ic, struct page_list *pl,
					       unsigned section, unsigned offset, unsigned *n_sectors)
{
	unsigned pl_index, pl_offset;
	char *va;

	page_list_location(ic, section, offset, &pl_index, &pl_offset);

	if (n_sectors)
		*n_sectors = (PAGE_SIZE - pl_offset) >> SECTOR_SHIFT;

	va = lowmem_page_address(pl[pl_index].page);

	return (struct journal_sector *)(va + pl_offset);
}

static struct journal_sector *access_journal(struct dm_integrity_c *ic, unsigned section, unsigned offset)
{
	return access_page_list(ic, ic->journal, section, offset, NULL);
}

static struct journal_entry *access_journal_entry(struct dm_integrity_c *ic, unsigned section, unsigned n)
{
	unsigned rel_sector, offset;
	struct journal_sector *js;

	access_journal_check(ic, section, n, true, "access_journal_entry");

	rel_sector = n % JOURNAL_BLOCK_SECTORS;
	offset = n / JOURNAL_BLOCK_SECTORS;

	js = access_journal(ic, section, rel_sector);
	return (struct journal_entry *)((char *)js + offset * ic->journal_entry_size);
}

static struct journal_sector *access_journal_data(struct dm_integrity_c *ic, unsigned section, unsigned n)
{
	n <<= ic->sb->log2_sectors_per_block;

	n += JOURNAL_BLOCK_SECTORS;

	access_journal_check(ic, section, n, false, "access_journal_data");

	return access_journal(ic, section, n);
}

static void section_mac(struct dm_integrity_c *ic, unsigned section, __u8 result[JOURNAL_MAC_SIZE])
{
	SHASH_DESC_ON_STACK(desc, ic->journal_mac);
	int r;
	unsigned j, size;

	desc->tfm = ic->journal_mac;

	r = crypto_shash_init(desc);
	if (unlikely(r < 0)) {
		dm_integrity_io_error(ic, "crypto_shash_init", r);
		goto err;
	}

	if (ic->sb->flags & cpu_to_le32(SB_FLAG_FIXED_HMAC)) {
		__le64 section_le;

		r = crypto_shash_update(desc, (__u8 *)&ic->sb->salt, SALT_SIZE);
		if (unlikely(r < 0)) {
			dm_integrity_io_error(ic, "crypto_shash_update", r);
			goto err;
		}

		section_le = cpu_to_le64(section);
		r = crypto_shash_update(desc, (__u8 *)&section_le, sizeof section_le);
		if (unlikely(r < 0)) {
			dm_integrity_io_error(ic, "crypto_shash_update", r);
			goto err;
		}
	}

	for (j = 0; j < ic->journal_section_entries; j++) {
		struct journal_entry *je = access_journal_entry(ic, section, j);
		r = crypto_shash_update(desc, (__u8 *)&je->u.sector, sizeof je->u.sector);
		if (unlikely(r < 0)) {
			dm_integrity_io_error(ic, "crypto_shash_update", r);
			goto err;
		}
	}

	size = crypto_shash_digestsize(ic->journal_mac);

	if (likely(size <= JOURNAL_MAC_SIZE)) {
		r = crypto_shash_final(desc, result);
		if (unlikely(r < 0)) {
			dm_integrity_io_error(ic, "crypto_shash_final", r);
			goto err;
		}
		memset(result + size, 0, JOURNAL_MAC_SIZE - size);
	} else {
		__u8 digest[HASH_MAX_DIGESTSIZE];

		if (WARN_ON(size > sizeof(digest))) {
			dm_integrity_io_error(ic, "digest_size", -EINVAL);
			goto err;
		}
		r = crypto_shash_final(desc, digest);
		if (unlikely(r < 0)) {
			dm_integrity_io_error(ic, "crypto_shash_final", r);
			goto err;
		}
		memcpy(result, digest, JOURNAL_MAC_SIZE);
	}

	return;
err:
	memset(result, 0, JOURNAL_MAC_SIZE);
}

static void rw_section_mac(struct dm_integrity_c *ic, unsigned section, bool wr)
{
	__u8 result[JOURNAL_MAC_SIZE];
	unsigned j;

	if (!ic->journal_mac)
		return;

	section_mac(ic, section, result);

	for (j = 0; j < JOURNAL_BLOCK_SECTORS; j++) {
		struct journal_sector *js = access_journal(ic, section, j);

		if (likely(wr))
			memcpy(&js->mac, result + (j * JOURNAL_MAC_PER_SECTOR), JOURNAL_MAC_PER_SECTOR);
		else {
			if (memcmp(&js->mac, result + (j * JOURNAL_MAC_PER_SECTOR), JOURNAL_MAC_PER_SECTOR)) {
				dm_integrity_io_error(ic, "journal mac", -EILSEQ);
				dm_audit_log_target(DM_MSG_PREFIX, "mac-journal", ic->ti, 0);
			}
		}
	}
}

static void complete_journal_op(void *context)
{
	struct journal_completion *comp = context;
	BUG_ON(!atomic_read(&comp->in_flight));
	if (likely(atomic_dec_and_test(&comp->in_flight)))
		complete(&comp->comp);
}

static void xor_journal(struct dm_integrity_c *ic, bool encrypt, unsigned section,
			unsigned n_sections, struct journal_completion *comp)
{
	struct async_submit_ctl submit;
	size_t n_bytes = (size_t)(n_sections * ic->journal_section_sectors) << SECTOR_SHIFT;
	unsigned pl_index, pl_offset, section_index;
	struct page_list *source_pl, *target_pl;

	if (likely(encrypt)) {
		source_pl = ic->journal;
		target_pl = ic->journal_io;
	} else {
		source_pl = ic->journal_io;
		target_pl = ic->journal;
	}

	page_list_location(ic, section, 0, &pl_index, &pl_offset);

	atomic_add(roundup(pl_offset + n_bytes, PAGE_SIZE) >> PAGE_SHIFT, &comp->in_flight);

	init_async_submit(&submit, ASYNC_TX_XOR_ZERO_DST, NULL, complete_journal_op, comp, NULL);

	section_index = pl_index;

	do {
		size_t this_step;
		struct page *src_pages[2];
		struct page *dst_page;

		while (unlikely(pl_index == section_index)) {
			unsigned dummy;
			if (likely(encrypt))
				rw_section_mac(ic, section, true);
			section++;
			n_sections--;
			if (!n_sections)
				break;
			page_list_location(ic, section, 0, &section_index, &dummy);
		}

		this_step = min(n_bytes, (size_t)PAGE_SIZE - pl_offset);
		dst_page = target_pl[pl_index].page;
		src_pages[0] = source_pl[pl_index].page;
		src_pages[1] = ic->journal_xor[pl_index].page;

		async_xor(dst_page, src_pages, pl_offset, 2, this_step, &submit);

		pl_index++;
		pl_offset = 0;
		n_bytes -= this_step;
	} while (n_bytes);

	BUG_ON(n_sections);

	async_tx_issue_pending_all();
}

static void complete_journal_encrypt(struct crypto_async_request *req, int err)
{
	struct journal_completion *comp = req->data;
	if (unlikely(err)) {
		if (likely(err == -EINPROGRESS)) {
			complete(&comp->ic->crypto_backoff);
			return;
		}
		dm_integrity_io_error(comp->ic, "asynchronous encrypt", err);
	}
	complete_journal_op(comp);
}

static bool do_crypt(bool encrypt, struct skcipher_request *req, struct journal_completion *comp)
{
	int r;
	skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
				      complete_journal_encrypt, comp);
	if (likely(encrypt))
		r = crypto_skcipher_encrypt(req);
	else
		r = crypto_skcipher_decrypt(req);
	if (likely(!r))
		return false;
	if (likely(r == -EINPROGRESS))
		return true;
	if (likely(r == -EBUSY)) {
		wait_for_completion(&comp->ic->crypto_backoff);
		reinit_completion(&comp->ic->crypto_backoff);
		return true;
	}
	dm_integrity_io_error(comp->ic, "encrypt", r);
	return false;
}

static void crypt_journal(struct dm_integrity_c *ic, bool encrypt, unsigned section,
			  unsigned n_sections, struct journal_completion *comp)
{
	struct scatterlist **source_sg;
	struct scatterlist **target_sg;

	atomic_add(2, &comp->in_flight);

	if (likely(encrypt)) {
		source_sg = ic->journal_scatterlist;
		target_sg = ic->journal_io_scatterlist;
	} else {
		source_sg = ic->journal_io_scatterlist;
		target_sg = ic->journal_scatterlist;
	}

	do {
		struct skcipher_request *req;
		unsigned ivsize;
		char *iv;

		if (likely(encrypt))
			rw_section_mac(ic, section, true);

		req = ic->sk_requests[section];
		ivsize = crypto_skcipher_ivsize(ic->journal_crypt);
		iv = req->iv;

		memcpy(iv, iv + ivsize, ivsize);

		req->src = source_sg[section];
		req->dst = target_sg[section];

		if (unlikely(do_crypt(encrypt, req, comp)))
			atomic_inc(&comp->in_flight);

		section++;
		n_sections--;
	} while (n_sections);

	atomic_dec(&comp->in_flight);
	complete_journal_op(comp);
}

static void encrypt_journal(struct dm_integrity_c *ic, bool encrypt, unsigned section,
			    unsigned n_sections, struct journal_completion *comp)
{
	if (ic->journal_xor)
		return xor_journal(ic, encrypt, section, n_sections, comp);
	else
		return crypt_journal(ic, encrypt, section, n_sections, comp);
}

static void complete_journal_io(unsigned long error, void *context)
{
	struct journal_completion *comp = context;
	if (unlikely(error != 0))
		dm_integrity_io_error(comp->ic, "writing journal", -EIO);
	complete_journal_op(comp);
}

static void rw_journal_sectors(struct dm_integrity_c *ic, int op, int op_flags,
			       unsigned sector, unsigned n_sectors, struct journal_completion *comp)
{
	struct dm_io_request io_req;
	struct dm_io_region io_loc;
	unsigned pl_index, pl_offset;
	int r;

	if (unlikely(dm_integrity_failed(ic))) {
		if (comp)
			complete_journal_io(-1UL, comp);
		return;
	}

	pl_index = sector >> (PAGE_SHIFT - SECTOR_SHIFT);
	pl_offset = (sector << SECTOR_SHIFT) & (PAGE_SIZE - 1);

	io_req.bi_op = op;
	io_req.bi_op_flags = op_flags;
	io_req.mem.type = DM_IO_PAGE_LIST;
	if (ic->journal_io)
		io_req.mem.ptr.pl = &ic->journal_io[pl_index];
	else
		io_req.mem.ptr.pl = &ic->journal[pl_index];
	io_req.mem.offset = pl_offset;
	if (likely(comp != NULL)) {
		io_req.notify.fn = complete_journal_io;
		io_req.notify.context = comp;
	} else {
		io_req.notify.fn = NULL;
	}
	io_req.client = ic->io;
	io_loc.bdev = ic->meta_dev ? ic->meta_dev->bdev : ic->dev->bdev;
	io_loc.sector = ic->start + SB_SECTORS + sector;
	io_loc.count = n_sectors;

	r = dm_io(&io_req, 1, &io_loc, NULL);
	if (unlikely(r)) {
		dm_integrity_io_error(ic, op == REQ_OP_READ ? "reading journal" : "writing journal", r);
		if (comp) {
			WARN_ONCE(1, "asynchronous dm_io failed: %d", r);
			complete_journal_io(-1UL, comp);
		}
	}
}

static void rw_journal(struct dm_integrity_c *ic, int op, int op_flags, unsigned section,
		       unsigned n_sections, struct journal_completion *comp)
{
	unsigned sector, n_sectors;

	sector = section * ic->journal_section_sectors;
	n_sectors = n_sections * ic->journal_section_sectors;

	rw_journal_sectors(ic, op, op_flags, sector, n_sectors, comp);
}

static void write_journal(struct dm_integrity_c *ic, unsigned commit_start, unsigned commit_sections)
{
	struct journal_completion io_comp;
	struct journal_completion crypt_comp_1;
	struct journal_completion crypt_comp_2;
	unsigned i;

	io_comp.ic = ic;
	init_completion(&io_comp.comp);

	if (commit_start + commit_sections <= ic->journal_sections) {
		io_comp.in_flight = (atomic_t)ATOMIC_INIT(1);
		if (ic->journal_io) {
			crypt_comp_1.ic = ic;
			init_completion(&crypt_comp_1.comp);
			crypt_comp_1.in_flight = (atomic_t)ATOMIC_INIT(0);
			encrypt_journal(ic, true, commit_start, commit_sections, &crypt_comp_1);
			wait_for_completion_io(&crypt_comp_1.comp);
		} else {
			for (i = 0; i < commit_sections; i++)
				rw_section_mac(ic, commit_start + i, true);
		}
		rw_journal(ic, REQ_OP_WRITE, REQ_FUA | REQ_SYNC, commit_start,
			   commit_sections, &io_comp);
	} else {
		unsigned to_end;
		io_comp.in_flight = (atomic_t)ATOMIC_INIT(2);
		to_end = ic->journal_sections - commit_start;
		if (ic->journal_io) {
			crypt_comp_1.ic = ic;
			init_completion(&crypt_comp_1.comp);
			crypt_comp_1.in_flight = (atomic_t)ATOMIC_INIT(0);
			encrypt_journal(ic, true, commit_start, to_end, &crypt_comp_1);
			if (try_wait_for_completion(&crypt_comp_1.comp)) {
				rw_journal(ic, REQ_OP_WRITE, REQ_FUA, commit_start, to_end, &io_comp);
				reinit_completion(&crypt_comp_1.comp);
				crypt_comp_1.in_flight = (atomic_t)ATOMIC_INIT(0);
				encrypt_journal(ic, true, 0, commit_sections - to_end, &crypt_comp_1);
				wait_for_completion_io(&crypt_comp_1.comp);
			} else {
				crypt_comp_2.ic = ic;
				init_completion(&crypt_comp_2.comp);
				crypt_comp_2.in_flight = (atomic_t)ATOMIC_INIT(0);
				encrypt_journal(ic, true, 0, commit_sections - to_end, &crypt_comp_2);
				wait_for_completion_io(&crypt_comp_1.comp);
				rw_journal(ic, REQ_OP_WRITE, REQ_FUA, commit_start, to_end, &io_comp);
				wait_for_completion_io(&crypt_comp_2.comp);
			}
		} else {
			for (i = 0; i < to_end; i++)
				rw_section_mac(ic, commit_start + i, true);
			rw_journal(ic, REQ_OP_WRITE, REQ_FUA, commit_start, to_end, &io_comp);
			for (i = 0; i < commit_sections - to_end; i++)
				rw_section_mac(ic, i, true);
		}
		rw_journal(ic, REQ_OP_WRITE, REQ_FUA, 0, commit_sections - to_end, &io_comp);
	}

	wait_for_completion_io(&io_comp.comp);
}

static void copy_from_journal(struct dm_integrity_c *ic, unsigned section, unsigned offset,
			      unsigned n_sectors, sector_t target, io_notify_fn fn, void *data)
{
	struct dm_io_request io_req;
	struct dm_io_region io_loc;
	int r;
	unsigned sector, pl_index, pl_offset;

	BUG_ON((target | n_sectors | offset) & (unsigned)(ic->sectors_per_block - 1));

	if (unlikely(dm_integrity_failed(ic))) {
		fn(-1UL, data);
		return;
	}

	sector = section * ic->journal_section_sectors + JOURNAL_BLOCK_SECTORS + offset;

	pl_index = sector >> (PAGE_SHIFT - SECTOR_SHIFT);
	pl_offset = (sector << SECTOR_SHIFT) & (PAGE_SIZE - 1);

	io_req.bi_op = REQ_OP_WRITE;
	io_req.bi_op_flags = 0;
	io_req.mem.type = DM_IO_PAGE_LIST;
	io_req.mem.ptr.pl = &ic->journal[pl_index];
	io_req.mem.offset = pl_offset;
	io_req.notify.fn = fn;
	io_req.notify.context = data;
	io_req.client = ic->io;
	io_loc.bdev = ic->dev->bdev;
	io_loc.sector = target;
	io_loc.count = n_sectors;

	r = dm_io(&io_req, 1, &io_loc, NULL);
	if (unlikely(r)) {
		WARN_ONCE(1, "asynchronous dm_io failed: %d", r);
		fn(-1UL, data);
	}
}

static bool ranges_overlap(struct dm_integrity_range *range1, struct dm_integrity_range *range2)
{
	return range1->logical_sector < range2->logical_sector + range2->n_sectors &&
	       range1->logical_sector + range1->n_sectors > range2->logical_sector;
}

static bool add_new_range(struct dm_integrity_c *ic, struct dm_integrity_range *new_range, bool check_waiting)
{
	struct rb_node **n = &ic->in_progress.rb_node;
	struct rb_node *parent;

	BUG_ON((new_range->logical_sector | new_range->n_sectors) & (unsigned)(ic->sectors_per_block - 1));

	if (likely(check_waiting)) {
		struct dm_integrity_range *range;
		list_for_each_entry(range, &ic->wait_list, wait_entry) {
			if (unlikely(ranges_overlap(range, new_range)))
				return false;
		}
	}

	parent = NULL;

	while (*n) {
		struct dm_integrity_range *range = container_of(*n, struct dm_integrity_range, node);

		parent = *n;
		if (new_range->logical_sector + new_range->n_sectors <= range->logical_sector) {
			n = &range->node.rb_left;
		} else if (new_range->logical_sector >= range->logical_sector + range->n_sectors) {
			n = &range->node.rb_right;
		} else {
			return false;
		}
	}

	rb_link_node(&new_range->node, parent, n);
	rb_insert_color(&new_range->node, &ic->in_progress);

	return true;
}

static void remove_range_unlocked(struct dm_integrity_c *ic, struct dm_integrity_range *range)
{
	rb_erase(&range->node, &ic->in_progress);
	while (unlikely(!list_empty(&ic->wait_list))) {
		struct dm_integrity_range *last_range =
			list_first_entry(&ic->wait_list, struct dm_integrity_range, wait_entry);
		struct task_struct *last_range_task;
		last_range_task = last_range->task;
		list_del(&last_range->wait_entry);
		if (!add_new_range(ic, last_range, false)) {
			last_range->task = last_range_task;
			list_add(&last_range->wait_entry, &ic->wait_list);
			break;
		}
		last_range->waiting = false;
		wake_up_process(last_range_task);
	}
}

static void remove_range(struct dm_integrity_c *ic, struct dm_integrity_range *range)
{
	unsigned long flags;

	spin_lock_irqsave(&ic->endio_wait.lock, flags);
	remove_range_unlocked(ic, range);
	spin_unlock_irqrestore(&ic->endio_wait.lock, flags);
}

static void wait_and_add_new_range(struct dm_integrity_c *ic, struct dm_integrity_range *new_range)
{
	new_range->waiting = true;
	list_add_tail(&new_range->wait_entry, &ic->wait_list);
	new_range->task = current;
	do {
		__set_current_state(TASK_UNINTERRUPTIBLE);
		spin_unlock_irq(&ic->endio_wait.lock);
		io_schedule();
		spin_lock_irq(&ic->endio_wait.lock);
	} while (unlikely(new_range->waiting));
}

static void add_new_range_and_wait(struct dm_integrity_c *ic, struct dm_integrity_range *new_range)
{
	if (unlikely(!add_new_range(ic, new_range, true)))
		wait_and_add_new_range(ic, new_range);
}

static void init_journal_node(struct journal_node *node)
{
	RB_CLEAR_NODE(&node->node);
	node->sector = (sector_t)-1;
}

static void add_journal_node(struct dm_integrity_c *ic, struct journal_node *node, sector_t sector)
{
	struct rb_node **link;
	struct rb_node *parent;

	node->sector = sector;
	BUG_ON(!RB_EMPTY_NODE(&node->node));

	link = &ic->journal_tree_root.rb_node;
	parent = NULL;

	while (*link) {
		struct journal_node *j;
		parent = *link;
		j = container_of(parent, struct journal_node, node);
		if (sector < j->sector)
			link = &j->node.rb_left;
		else
			link = &j->node.rb_right;
	}

	rb_link_node(&node->node, parent, link);
	rb_insert_color(&node->node, &ic->journal_tree_root);
}

static void remove_journal_node(struct dm_integrity_c *ic, struct journal_node *node)
{
	BUG_ON(RB_EMPTY_NODE(&node->node));
	rb_erase(&node->node, &ic->journal_tree_root);
	init_journal_node(node);
}

#define NOT_FOUND	(-1U)

static unsigned find_journal_node(struct dm_integrity_c *ic, sector_t sector, sector_t *next_sector)
{
	struct rb_node *n = ic->journal_tree_root.rb_node;
	unsigned found = NOT_FOUND;
	*next_sector = (sector_t)-1;
	while (n) {
		struct journal_node *j = container_of(n, struct journal_node, node);
		if (sector == j->sector) {
			found = j - ic->journal_tree;
		}
		if (sector < j->sector) {
			*next_sector = j->sector;
			n = j->node.rb_left;
		} else {
			n = j->node.rb_right;
		}
	}

	return found;
}

static bool test_journal_node(struct dm_integrity_c *ic, unsigned pos, sector_t sector)
{
	struct journal_node *node, *next_node;
	struct rb_node *next;

	if (unlikely(pos >= ic->journal_entries))
		return false;
	node = &ic->journal_tree[pos];
	if (unlikely(RB_EMPTY_NODE(&node->node)))
		return false;
	if (unlikely(node->sector != sector))
		return false;

	next = rb_next(&node->node);
	if (unlikely(!next))
		return true;

	next_node = container_of(next, struct journal_node, node);
	return next_node->sector != sector;
}

static bool find_newer_committed_node(struct dm_integrity_c *ic, struct journal_node *node)
{
	struct rb_node *next;
	struct journal_node *next_node;
	unsigned next_section;

	BUG_ON(RB_EMPTY_NODE(&node->node));

	next = rb_next(&node->node);
	if (unlikely(!next))
		return false;

	next_node = container_of(next, struct journal_node, node);

	if (next_node->sector != node->sector)
		return false;

	next_section = (unsigned)(next_node - ic->journal_tree) / ic->journal_section_entries;
	if (next_section >= ic->committed_section &&
	    next_section < ic->committed_section + ic->n_committed_sections)
		return true;
	if (next_section + ic->journal_sections < ic->committed_section + ic->n_committed_sections)
		return true;

	return false;
}

#define TAG_READ	0
#define TAG_WRITE	1
#define TAG_CMP		2

static int dm_integrity_rw_tag(struct dm_integrity_c *ic, unsigned char *tag, sector_t *metadata_block,
			       unsigned *metadata_offset, unsigned total_size, int op)
{
#define MAY_BE_FILLER		1
#define MAY_BE_HASH		2
	unsigned hash_offset = 0;
	unsigned may_be = MAY_BE_HASH | (ic->discard ? MAY_BE_FILLER : 0);

	do {
		unsigned char *data, *dp;
		struct dm_buffer *b;
		unsigned to_copy;
		int r;

		r = dm_integrity_failed(ic);
		if (unlikely(r))
			return r;

		data = dm_bufio_read(ic->bufio, *metadata_block, &b);
		if (IS_ERR(data))
			return PTR_ERR(data);

		to_copy = min((1U << SECTOR_SHIFT << ic->log2_buffer_sectors) - *metadata_offset, total_size);
		dp = data + *metadata_offset;
		if (op == TAG_READ) {
			memcpy(tag, dp, to_copy);
		} else if (op == TAG_WRITE) {
			if (memcmp(dp, tag, to_copy)) {
				memcpy(dp, tag, to_copy);
				dm_bufio_mark_partial_buffer_dirty(b, *metadata_offset, *metadata_offset + to_copy);
			}
		} else {
			/* e.g.: op == TAG_CMP */

			if (likely(is_power_of_2(ic->tag_size))) {
				if (unlikely(memcmp(dp, tag, to_copy)))
					if (unlikely(!ic->discard) ||
					    unlikely(memchr_inv(dp, DISCARD_FILLER, to_copy) != NULL)) {
						goto thorough_test;
				}
			} else {
				unsigned i, ts;
thorough_test:
				ts = total_size;

				for (i = 0; i < to_copy; i++, ts--) {
					if (unlikely(dp[i] != tag[i]))
						may_be &= ~MAY_BE_HASH;
					if (likely(dp[i] != DISCARD_FILLER))
						may_be &= ~MAY_BE_FILLER;
					hash_offset++;
					if (unlikely(hash_offset == ic->tag_size)) {
						if (unlikely(!may_be)) {
							dm_bufio_release(b);
							return ts;
						}
						hash_offset = 0;
						may_be = MAY_BE_HASH | (ic->discard ? MAY_BE_FILLER : 0);
					}
				}
			}
		}
		dm_bufio_release(b);

		tag += to_copy;
		*metadata_offset += to_copy;
		if (unlikely(*metadata_offset == 1U << SECTOR_SHIFT << ic->log2_buffer_sectors)) {
			(*metadata_block)++;
			*metadata_offset = 0;
		}

		if (unlikely(!is_power_of_2(ic->tag_size))) {
			hash_offset = (hash_offset + to_copy) % ic->tag_size;
		}

		total_size -= to_copy;
	} while (unlikely(total_size));

	return 0;
#undef MAY_BE_FILLER
#undef MAY_BE_HASH
}

struct flush_request {
	struct dm_io_request io_req;
	struct dm_io_region io_reg;
	struct dm_integrity_c *ic;
	struct completion comp;
};

static void flush_notify(unsigned long error, void *fr_)
{
	struct flush_request *fr = fr_;
	if (unlikely(error != 0))
		dm_integrity_io_error(fr->ic, "flushing disk cache", -EIO);
	complete(&fr->comp);
}

static void dm_integrity_flush_buffers(struct dm_integrity_c *ic, bool flush_data)
{
	int r;

	struct flush_request fr;

	if (!ic->meta_dev)
		flush_data = false;
	if (flush_data) {
		fr.io_req.bi_op = REQ_OP_WRITE,
		fr.io_req.bi_op_flags = REQ_PREFLUSH | REQ_SYNC,
		fr.io_req.mem.type = DM_IO_KMEM,
		fr.io_req.mem.ptr.addr = NULL,
		fr.io_req.notify.fn = flush_notify,
		fr.io_req.notify.context = &fr;
		fr.io_req.client = dm_bufio_get_dm_io_client(ic->bufio),
		fr.io_reg.bdev = ic->dev->bdev,
		fr.io_reg.sector = 0,
		fr.io_reg.count = 0,
		fr.ic = ic;
		init_completion(&fr.comp);
		r = dm_io(&fr.io_req, 1, &fr.io_reg, NULL);
		BUG_ON(r);
	}

	r = dm_bufio_write_dirty_buffers(ic->bufio);
	if (unlikely(r))
		dm_integrity_io_error(ic, "writing tags", r);

	if (flush_data)
		wait_for_completion(&fr.comp);
}

static void sleep_on_endio_wait(struct dm_integrity_c *ic)
{
	DECLARE_WAITQUEUE(wait, current);
	__add_wait_queue(&ic->endio_wait, &wait);
	__set_current_state(TASK_UNINTERRUPTIBLE);
	spin_unlock_irq(&ic->endio_wait.lock);
	io_schedule();
	spin_lock_irq(&ic->endio_wait.lock);
	__remove_wait_queue(&ic->endio_wait, &wait);
}

static void autocommit_fn(struct timer_list *t)
{
	struct dm_integrity_c *ic = from_timer(ic, t, autocommit_timer);

	if (likely(!dm_integrity_failed(ic)))
		queue_work(ic->commit_wq, &ic->commit_work);
}

static void schedule_autocommit(struct dm_integrity_c *ic)
{
	if (!timer_pending(&ic->autocommit_timer))
		mod_timer(&ic->autocommit_timer, jiffies + ic->autocommit_jiffies);
}

static void submit_flush_bio(struct dm_integrity_c *ic, struct dm_integrity_io *dio)
{
	struct bio *bio;
	unsigned long flags;

	spin_lock_irqsave(&ic->endio_wait.lock, flags);
	bio = dm_bio_from_per_bio_data(dio, sizeof(struct dm_integrity_io));
	bio_list_add(&ic->flush_bio_list, bio);
	spin_unlock_irqrestore(&ic->endio_wait.lock, flags);

	queue_work(ic->commit_wq, &ic->commit_work);
}

static void do_endio(struct dm_integrity_c *ic, struct bio *bio)
{
	int r = dm_integrity_failed(ic);
	if (unlikely(r) && !bio->bi_status)
		bio->bi_status = errno_to_blk_status(r);
	if (unlikely(ic->synchronous_mode) && bio_op(bio) == REQ_OP_WRITE) {
		unsigned long flags;
		spin_lock_irqsave(&ic->endio_wait.lock, flags);
		bio_list_add(&ic->synchronous_bios, bio);
		queue_delayed_work(ic->commit_wq, &ic->bitmap_flush_work, 0);
		spin_unlock_irqrestore(&ic->endio_wait.lock, flags);
		return;
	}
	bio_endio(bio);
}

static void do_endio_flush(struct dm_integrity_c *ic, struct dm_integrity_io *dio)
{
	struct bio *bio = dm_bio_from_per_bio_data(dio, sizeof(struct dm_integrity_io));

	if (unlikely(dio->fua) && likely(!bio->bi_status) && likely(!dm_integrity_failed(ic)))
		submit_flush_bio(ic, dio);
	else
		do_endio(ic, bio);
}

static void dec_in_flight(struct dm_integrity_io *dio)
{
	if (atomic_dec_and_test(&dio->in_flight)) {
		struct dm_integrity_c *ic = dio->ic;
		struct bio *bio;

		remove_range(ic, &dio->range);

		if (dio->op == REQ_OP_WRITE || unlikely(dio->op == REQ_OP_DISCARD))
			schedule_autocommit(ic);

		bio = dm_bio_from_per_bio_data(dio, sizeof(struct dm_integrity_io));

		if (unlikely(dio->bi_status) && !bio->bi_status)
			bio->bi_status = dio->bi_status;
		if (likely(!bio->bi_status) && unlikely(bio_sectors(bio) != dio->range.n_sectors)) {
			dio->range.logical_sector += dio->range.n_sectors;
			bio_advance(bio, dio->range.n_sectors << SECTOR_SHIFT);
			INIT_WORK(&dio->work, integrity_bio_wait);
			queue_work(ic->offload_wq, &dio->work);
			return;
		}
		do_endio_flush(ic, dio);
	}
}

static void integrity_end_io(struct bio *bio)
{
	struct dm_integrity_io *dio = dm_per_bio_data(bio, sizeof(struct dm_integrity_io));

	dm_bio_restore(&dio->bio_details, bio);
	if (bio->bi_integrity)
		bio->bi_opf |= REQ_INTEGRITY;

	if (dio->completion)
		complete(dio->completion);

	dec_in_flight(dio);
}

static void integrity_sector_checksum(struct dm_integrity_c *ic, sector_t sector,
				      const char *data, char *result)
{
	__le64 sector_le = cpu_to_le64(sector);
	SHASH_DESC_ON_STACK(req, ic->internal_hash);
	int r;
	unsigned digest_size;

	req->tfm = ic->internal_hash;

	r = crypto_shash_init(req);
	if (unlikely(r < 0)) {
		dm_integrity_io_error(ic, "crypto_shash_init", r);
		goto failed;
	}

	if (ic->sb->flags & cpu_to_le32(SB_FLAG_FIXED_HMAC)) {
		r = crypto_shash_update(req, (__u8 *)&ic->sb->salt, SALT_SIZE);
		if (unlikely(r < 0)) {
			dm_integrity_io_error(ic, "crypto_shash_update", r);
			goto failed;
		}
	}

	r = crypto_shash_update(req, (const __u8 *)&sector_le, sizeof sector_le);
	if (unlikely(r < 0)) {
		dm_integrity_io_error(ic, "crypto_shash_update", r);
		goto failed;
	}

	r = crypto_shash_update(req, data, ic->sectors_per_block << SECTOR_SHIFT);
	if (unlikely(r < 0)) {
		dm_integrity_io_error(ic, "crypto_shash_update", r);
		goto failed;
	}

	r = crypto_shash_final(req, result);
	if (unlikely(r < 0)) {
		dm_integrity_io_error(ic, "crypto_shash_final", r);
		goto failed;
	}

	digest_size = crypto_shash_digestsize(ic->internal_hash);
	if (unlikely(digest_size < ic->tag_size))
		memset(result + digest_size, 0, ic->tag_size - digest_size);

	return;

failed:
	/* this shouldn't happen anyway, the hash functions have no reason to fail */
	get_random_bytes(result, ic->tag_size);
}

static void integrity_metadata(struct work_struct *w)
{
	struct dm_integrity_io *dio = container_of(w, struct dm_integrity_io, work);
	struct dm_integrity_c *ic = dio->ic;

	int r;

	if (ic->internal_hash) {
		struct bvec_iter iter;
		struct bio_vec bv;
		unsigned digest_size = crypto_shash_digestsize(ic->internal_hash);
		struct bio *bio = dm_bio_from_per_bio_data(dio, sizeof(struct dm_integrity_io));
		char *checksums;
		unsigned extra_space = unlikely(digest_size > ic->tag_size) ? digest_size - ic->tag_size : 0;
		char checksums_onstack[max((size_t)HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)];
		sector_t sector;
		unsigned sectors_to_process;

		if (unlikely(ic->mode == 'R'))
			goto skip_io;

		if (likely(dio->op != REQ_OP_DISCARD))
			checksums = kmalloc((PAGE_SIZE >> SECTOR_SHIFT >> ic->sb->log2_sectors_per_block) * ic->tag_size + extra_space,
					    GFP_NOIO | __GFP_NORETRY | __GFP_NOWARN);
		else
			checksums = kmalloc(PAGE_SIZE, GFP_NOIO | __GFP_NORETRY | __GFP_NOWARN);
		if (!checksums) {
			checksums = checksums_onstack;
			if (WARN_ON(extra_space &&
				    digest_size > sizeof(checksums_onstack))) {
				r = -EINVAL;
				goto error;
			}
		}

		if (unlikely(dio->op == REQ_OP_DISCARD)) {
			sector_t bi_sector = dio->bio_details.bi_iter.bi_sector;
			unsigned bi_size = dio->bio_details.bi_iter.bi_size;
			unsigned max_size = likely(checksums != checksums_onstack) ? PAGE_SIZE : HASH_MAX_DIGESTSIZE;
			unsigned max_blocks = max_size / ic->tag_size;
			memset(checksums, DISCARD_FILLER, max_size);

			while (bi_size) {
				unsigned this_step_blocks = bi_size >> (SECTOR_SHIFT + ic->sb->log2_sectors_per_block);
				this_step_blocks = min(this_step_blocks, max_blocks);
				r = dm_integrity_rw_tag(ic, checksums, &dio->metadata_block, &dio->metadata_offset,
							this_step_blocks * ic->tag_size, TAG_WRITE);
				if (unlikely(r)) {
					if (likely(checksums != checksums_onstack))
						kfree(checksums);
					goto error;
				}

				/*if (bi_size < this_step_blocks << (SECTOR_SHIFT + ic->sb->log2_sectors_per_block)) {
					printk("BUGG: bi_sector: %llx, bi_size: %u\n", bi_sector, bi_size);
					printk("BUGG: this_step_blocks: %u\n", this_step_blocks);
					BUG();
				}*/
				bi_size -= this_step_blocks << (SECTOR_SHIFT + ic->sb->log2_sectors_per_block);
				bi_sector += this_step_blocks << ic->sb->log2_sectors_per_block;
			}

			if (likely(checksums != checksums_onstack))
				kfree(checksums);
			goto skip_io;
		}

		sector = dio->range.logical_sector;
		sectors_to_process = dio->range.n_sectors;

		__bio_for_each_segment(bv, bio, iter, dio->bio_details.bi_iter) {
			unsigned pos;
			char *mem, *checksums_ptr;

again:
			mem = bvec_kmap_local(&bv);
			pos = 0;
			checksums_ptr = checksums;
			do {
				integrity_sector_checksum(ic, sector, mem + pos, checksums_ptr);
				checksums_ptr += ic->tag_size;
				sectors_to_process -= ic->sectors_per_block;
				pos += ic->sectors_per_block << SECTOR_SHIFT;
				sector += ic->sectors_per_block;
			} while (pos < bv.bv_len && sectors_to_process && checksums != checksums_onstack);
			kunmap_local(mem);

			r = dm_integrity_rw_tag(ic, checksums, &dio->metadata_block, &dio->metadata_offset,
						checksums_ptr - checksums, dio->op == REQ_OP_READ ? TAG_CMP : TAG_WRITE);
			if (unlikely(r)) {
				if (r > 0) {
					char b[BDEVNAME_SIZE];
					sector_t s;

					s = sector - ((r + ic->tag_size - 1) / ic->tag_size);
					DMERR_LIMIT("%s: Checksum failed at sector 0x%llx",
						    bio_devname(bio, b), s);
					r = -EILSEQ;
					atomic64_inc(&ic->number_of_mismatches);
					dm_audit_log_bio(DM_MSG_PREFIX, "integrity-checksum",
							 bio, s, 0);
				}
				if (likely(checksums != checksums_onstack))
					kfree(checksums);
				goto error;
			}

			if (!sectors_to_process)
				break;

			if (unlikely(pos < bv.bv_len)) {
				bv.bv_offset += pos;
				bv.bv_len -= pos;
				goto again;
			}
		}

		if (likely(checksums != checksums_onstack))
			kfree(checksums);
	} else {
		struct bio_integrity_payload *bip = dio->bio_details.bi_integrity;

		if (bip) {
			struct bio_vec biv;
			struct bvec_iter iter;
			unsigned data_to_process = dio->range.n_sectors;
			sector_to_block(ic, data_to_process);
			data_to_process *= ic->tag_size;

			bip_for_each_vec(biv, bip, iter) {
				unsigned char *tag;
				unsigned this_len;

				BUG_ON(PageHighMem(biv.bv_page));
				tag = bvec_virt(&biv);
				this_len = min(biv.bv_len, data_to_process);
				r = dm_integrity_rw_tag(ic, tag, &dio->metadata_block, &dio->metadata_offset,
							this_len, dio->op == REQ_OP_READ ? TAG_READ : TAG_WRITE);
				if (unlikely(r))
					goto error;
				data_to_process -= this_len;
				if (!data_to_process)
					break;
			}
		}
	}
skip_io:
	dec_in_flight(dio);
	return;
error:
	dio->bi_status = errno_to_blk_status(r);
	dec_in_flight(dio);
}

static int dm_integrity_map(struct dm_target *ti, struct bio *bio)
{
	struct dm_integrity_c *ic = ti->private;
	struct dm_integrity_io *dio = dm_per_bio_data(bio, sizeof(struct dm_integrity_io));
	struct bio_integrity_payload *bip;

	sector_t area, offset;

	dio->ic = ic;
	dio->bi_status = 0;
	dio->op = bio_op(bio);

	if (unlikely(dio->op == REQ_OP_DISCARD)) {
		if (ti->max_io_len) {
			sector_t sec = dm_target_offset(ti, bio->bi_iter.bi_sector);
			unsigned log2_max_io_len = __fls(ti->max_io_len);
			sector_t start_boundary = sec >> log2_max_io_len;
			sector_t end_boundary = (sec + bio_sectors(bio) - 1) >> log2_max_io_len;
			if (start_boundary < end_boundary) {
				sector_t len = ti->max_io_len - (sec & (ti->max_io_len - 1));
				dm_accept_partial_bio(bio, len);
			}
		}
	}

	if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {
		submit_flush_bio(ic, dio);
		return DM_MAPIO_SUBMITTED;
	}

	dio->range.logical_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
	dio->fua = dio->op == REQ_OP_WRITE && bio->bi_opf & REQ_FUA;
	if (unlikely(dio->fua)) {
		/*
		 * Don't pass down the FUA flag because we have to flush
		 * disk cache anyway.
		 */
		bio->bi_opf &= ~REQ_FUA;
	}
	if (unlikely(dio->range.logical_sector + bio_sectors(bio) > ic->provided_data_sectors)) {
		DMERR("Too big sector number: 0x%llx + 0x%x > 0x%llx",
		      dio->range.logical_sector, bio_sectors(bio),
		      ic->provided_data_sectors);
		return DM_MAPIO_KILL;
	}
	if (unlikely((dio->range.logical_sector | bio_sectors(bio)) & (unsigned)(ic->sectors_per_block - 1))) {
		DMERR("Bio not aligned on %u sectors: 0x%llx, 0x%x",
		      ic->sectors_per_block,
		      dio->range.logical_sector, bio_sectors(bio));
		return DM_MAPIO_KILL;
	}

	if (ic->sectors_per_block > 1 && likely(dio->op != REQ_OP_DISCARD)) {
		struct bvec_iter iter;
		struct bio_vec bv;
		bio_for_each_segment(bv, bio, iter) {
			if (unlikely(bv.bv_len & ((ic->sectors_per_block << SECTOR_SHIFT) - 1))) {
				DMERR("Bio vector (%u,%u) is not aligned on %u-sector boundary",
					bv.bv_offset, bv.bv_len, ic->sectors_per_block);
				return DM_MAPIO_KILL;
			}
		}
	}

	bip = bio_integrity(bio);
	if (!ic->internal_hash) {
		if (bip) {
			unsigned wanted_tag_size = bio_sectors(bio) >> ic->sb->log2_sectors_per_block;
			if (ic->log2_tag_size >= 0)
				wanted_tag_size <<= ic->log2_tag_size;
			else
				wanted_tag_size *= ic->tag_size;
			if (unlikely(wanted_tag_size != bip->bip_iter.bi_size)) {
				DMERR("Invalid integrity data size %u, expected %u",
				      bip->bip_iter.bi_size, wanted_tag_size);
				return DM_MAPIO_KILL;
			}
		}
	} else {
		if (unlikely(bip != NULL)) {
			DMERR("Unexpected integrity data when using internal hash");
			return DM_MAPIO_KILL;
		}
	}

	if (unlikely(ic->mode == 'R') && unlikely(dio->op != REQ_OP_READ))
		return DM_MAPIO_KILL;

	get_area_and_offset(ic, dio->range.logical_sector, &area, &offset);
	dio->metadata_block = get_metadata_sector_and_offset(ic, area, offset, &dio->metadata_offset);
	bio->bi_iter.bi_sector = get_data_sector(ic, area, offset);

	dm_integrity_map_continue(dio, true);
	return DM_MAPIO_SUBMITTED;
}

static bool __journal_read_write(struct dm_integrity_io *dio, struct bio *bio,
				 unsigned journal_section, unsigned journal_entry)
{
	struct dm_integrity_c *ic = dio->ic;
	sector_t logical_sector;
	unsigned n_sectors;

	logical_sector = dio->range.logical_sector;
	n_sectors = dio->range.n_sectors;
	do {
		struct bio_vec bv = bio_iovec(bio);
		char *mem;

		if (unlikely(bv.bv_len >> SECTOR_SHIFT > n_sectors))
			bv.bv_len = n_sectors << SECTOR_SHIFT;
		n_sectors -= bv.bv_len >> SECTOR_SHIFT;
		bio_advance_iter(bio, &bio->bi_iter, bv.bv_len);
retry_kmap:
		mem = bvec_kmap_local(&bv);
		if (likely(dio->op == REQ_OP_WRITE))
			flush_dcache_page(bv.bv_page);

		do {
			struct journal_entry *je = access_journal_entry(ic, journal_section, journal_entry);

			if (unlikely(dio->op == REQ_OP_READ)) {
				struct journal_sector *js;
				char *mem_ptr;
				unsigned s;

				if (unlikely(journal_entry_is_inprogress(je))) {
					flush_dcache_page(bv.bv_page);
					kunmap_local(mem);

					__io_wait_event(ic->copy_to_journal_wait, !journal_entry_is_inprogress(je));
					goto retry_kmap;
				}
				smp_rmb();
				BUG_ON(journal_entry_get_sector(je) != logical_sector);
				js = access_journal_data(ic, journal_section, journal_entry);
				mem_ptr = mem + bv.bv_offset;
				s = 0;
				do {
					memcpy(mem_ptr, js, JOURNAL_SECTOR_DATA);
					*(commit_id_t *)(mem_ptr + JOURNAL_SECTOR_DATA) = je->last_bytes[s];
					js++;
					mem_ptr += 1 << SECTOR_SHIFT;
				} while (++s < ic->sectors_per_block);
#ifdef INTERNAL_VERIFY
				if (ic->internal_hash) {
					char checksums_onstack[max((size_t)HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)];

					integrity_sector_checksum(ic, logical_sector, mem + bv.bv_offset, checksums_onstack);
					if (unlikely(memcmp(checksums_onstack, journal_entry_tag(ic, je), ic->tag_size))) {
						DMERR_LIMIT("Checksum failed when reading from journal, at sector 0x%llx",
							    logical_sector);
						dm_audit_log_bio(DM_MSG_PREFIX, "journal-checksum",
								 bio, logical_sector, 0);
					}
				}
#endif
			}

			if (!ic->internal_hash) {
				struct bio_integrity_payload *bip = bio_integrity(bio);
				unsigned tag_todo = ic->tag_size;
				char *tag_ptr = journal_entry_tag(ic, je);

				if (bip) do {
					struct bio_vec biv = bvec_iter_bvec(bip->bip_vec, bip->bip_iter);
					unsigned tag_now = min(biv.bv_len, tag_todo);
					char *tag_addr;
					BUG_ON(PageHighMem(biv.bv_page));
					tag_addr = bvec_virt(&biv);
					if (likely(dio->op == REQ_OP_WRITE))
						memcpy(tag_ptr, tag_addr, tag_now);
					else
						memcpy(tag_addr, tag_ptr, tag_now);
					bvec_iter_advance(bip->bip_vec, &bip->bip_iter, tag_now);
					tag_ptr += tag_now;
					tag_todo -= tag_now;
				} while (unlikely(tag_todo)); else {
					if (likely(dio->op == REQ_OP_WRITE))
						memset(tag_ptr, 0, tag_todo);
				}
			}

			if (likely(dio->op == REQ_OP_WRITE)) {
				struct journal_sector *js;
				unsigned s;

				js = access_journal_data(ic, journal_section, journal_entry);
				memcpy(js, mem + bv.bv_offset, ic->sectors_per_block << SECTOR_SHIFT);

				s = 0;
				do {
					je->last_bytes[s] = js[s].commit_id;
				} while (++s < ic->sectors_per_block);

				if (ic->internal_hash) {
					unsigned digest_size = crypto_shash_digestsize(ic->internal_hash);
					if (unlikely(digest_size > ic->tag_size)) {
						char checksums_onstack[HASH_MAX_DIGESTSIZE];
						integrity_sector_checksum(ic, logical_sector, (char *)js, checksums_onstack);
						memcpy(journal_entry_tag(ic, je), checksums_onstack, ic->tag_size);
					} else
						integrity_sector_checksum(ic, logical_sector, (char *)js, journal_entry_tag(ic, je));
				}

				journal_entry_set_sector(je, logical_sector);
			}
			logical_sector += ic->sectors_per_block;

			journal_entry++;
			if (unlikely(journal_entry == ic->journal_section_entries)) {
				journal_entry = 0;
				journal_section++;
				wraparound_section(ic, &journal_section);
			}

			bv.bv_offset += ic->sectors_per_block << SECTOR_SHIFT;
		} while (bv.bv_len -= ic->sectors_per_block << SECTOR_SHIFT);

		if (unlikely(dio->op == REQ_OP_READ))
			flush_dcache_page(bv.bv_page);
		kunmap_local(mem);
	} while (n_sectors);

	if (likely(dio->op == REQ_OP_WRITE)) {
		smp_mb();
		if (unlikely(waitqueue_active(&ic->copy_to_journal_wait)))
			wake_up(&ic->copy_to_journal_wait);
		if (READ_ONCE(ic->free_sectors) <= ic->free_sectors_threshold) {
			queue_work(ic->commit_wq, &ic->commit_work);
		} else {
			schedule_autocommit(ic);
		}
	} else {
		remove_range(ic, &dio->range);
	}

	if (unlikely(bio->bi_iter.bi_size)) {
		sector_t area, offset;

		dio->range.logical_sector = logical_sector;
		get_area_and_offset(ic, dio->range.logical_sector, &area, &offset);
		dio->metadata_block = get_metadata_sector_and_offset(ic, area, offset, &dio->metadata_offset);
		return true;
	}

	return false;
}

static void dm_integrity_map_continue(struct dm_integrity_io *dio, bool from_map)
{
	struct dm_integrity_c *ic = dio->ic;
	struct bio *bio = dm_bio_from_per_bio_data(dio, sizeof(struct dm_integrity_io));
	unsigned journal_section, journal_entry;
	unsigned journal_read_pos;
	struct completion read_comp;
	bool discard_retried = false;
	bool need_sync_io = ic->internal_hash && dio->op == REQ_OP_READ;
	if (unlikely(dio->op == REQ_OP_DISCARD) && ic->mode != 'D')
		need_sync_io = true;

	if (need_sync_io && from_map) {
		INIT_WORK(&dio->work, integrity_bio_wait);
		queue_work(ic->offload_wq, &dio->work);
		return;
	}

lock_retry:
	spin_lock_irq(&ic->endio_wait.lock);
retry:
	if (unlikely(dm_integrity_failed(ic))) {
		spin_unlock_irq(&ic->endio_wait.lock);
		do_endio(ic, bio);
		return;
	}
	dio->range.n_sectors = bio_sectors(bio);
	journal_read_pos = NOT_FOUND;
	if (ic->mode == 'J' && likely(dio->op != REQ_OP_DISCARD)) {
		if (dio->op == REQ_OP_WRITE) {
			unsigned next_entry, i, pos;
			unsigned ws, we, range_sectors;

			dio->range.n_sectors = min(dio->range.n_sectors,
						   (sector_t)ic->free_sectors << ic->sb->log2_sectors_per_block);
			if (unlikely(!dio->range.n_sectors)) {
				if (from_map)
					goto offload_to_thread;
				sleep_on_endio_wait(ic);
				goto retry;
			}
			range_sectors = dio->range.n_sectors >> ic->sb->log2_sectors_per_block;
			ic->free_sectors -= range_sectors;
			journal_section = ic->free_section;
			journal_entry = ic->free_section_entry;

			next_entry = ic->free_section_entry + range_sectors;
			ic->free_section_entry = next_entry % ic->journal_section_entries;
			ic->free_section += next_entry / ic->journal_section_entries;
			ic->n_uncommitted_sections += next_entry / ic->journal_section_entries;
			wraparound_section(ic, &ic->free_section);

			pos = journal_section * ic->journal_section_entries + journal_entry;
			ws = journal_section;
			we = journal_entry;
			i = 0;
			do {
				struct journal_entry *je;

				add_journal_node(ic, &ic->journal_tree[pos], dio->range.logical_sector + i);
				pos++;
				if (unlikely(pos >= ic->journal_entries))
					pos = 0;

				je = access_journal_entry(ic, ws, we);
				BUG_ON(!journal_entry_is_unused(je));
				journal_entry_set_inprogress(je);
				we++;
				if (unlikely(we == ic->journal_section_entries)) {
					we = 0;
					ws++;
					wraparound_section(ic, &ws);
				}
			} while ((i += ic->sectors_per_block) < dio->range.n_sectors);

			spin_unlock_irq(&ic->endio_wait.lock);
			goto journal_read_write;
		} else {
			sector_t next_sector;
			journal_read_pos = find_journal_node(ic, dio->range.logical_sector, &next_sector);
			if (likely(journal_read_pos == NOT_FOUND)) {
				if (unlikely(dio->range.n_sectors > next_sector - dio->range.logical_sector))
					dio->range.n_sectors = next_sector - dio->range.logical_sector;
			} else {
				unsigned i;
				unsigned jp = journal_read_pos + 1;
				for (i = ic->sectors_per_block; i < dio->range.n_sectors; i += ic->sectors_per_block, jp++) {
					if (!test_journal_node(ic, jp, dio->range.logical_sector + i))
						break;
				}
				dio->range.n_sectors = i;
			}
		}
	}
	if (unlikely(!add_new_range(ic, &dio->range, true))) {
		/*
		 * We must not sleep in the request routine because it could
		 * stall bios on current->bio_list.
		 * So, we offload the bio to a workqueue if we have to sleep.
		 */
		if (from_map) {
offload_to_thread:
			spin_unlock_irq(&ic->endio_wait.lock);
			INIT_WORK(&dio->work, integrity_bio_wait);
			queue_work(ic->wait_wq, &dio->work);
			return;
		}
		if (journal_read_pos != NOT_FOUND)
			dio->range.n_sectors = ic->sectors_per_block;
		wait_and_add_new_range(ic, &dio->range);
		/*
		 * wait_and_add_new_range drops the spinlock, so the journal
		 * may have been changed arbitrarily. We need to recheck.
		 * To simplify the code, we restrict I/O size to just one block.
		 */
		if (journal_read_pos != NOT_FOUND) {
			sector_t next_sector;
			unsigned new_pos = find_journal_node(ic, dio->range.logical_sector, &next_sector);
			if (unlikely(new_pos != journal_read_pos)) {
				remove_range_unlocked(ic, &dio->range);
				goto retry;
			}
		}
	}
	if (ic->mode == 'J' && likely(dio->op == REQ_OP_DISCARD) && !discard_retried) {
		sector_t next_sector;
		unsigned new_pos = find_journal_node(ic, dio->range.logical_sector, &next_sector);
		if (unlikely(new_pos != NOT_FOUND) ||
		    unlikely(next_sector < dio->range.logical_sector - dio->range.n_sectors)) {
			remove_range_unlocked(ic, &dio->range);
			spin_unlock_irq(&ic->endio_wait.lock);
			queue_work(ic->commit_wq, &ic->commit_work);
			flush_workqueue(ic->commit_wq);
			queue_work(ic->writer_wq, &ic->writer_work);
			flush_workqueue(ic->writer_wq);
			discard_retried = true;
			goto lock_retry;
		}
	}
	spin_unlock_irq(&ic->endio_wait.lock);

	if (unlikely(journal_read_pos != NOT_FOUND)) {
		journal_section = journal_read_pos / ic->journal_section_entries;
		journal_entry = journal_read_pos % ic->journal_section_entries;
		goto journal_read_write;
	}

	if (ic->mode == 'B' && (dio->op == REQ_OP_WRITE || unlikely(dio->op == REQ_OP_DISCARD))) {
		if (!block_bitmap_op(ic, ic->may_write_bitmap, dio->range.logical_sector,
				     dio->range.n_sectors, BITMAP_OP_TEST_ALL_SET)) {
			struct bitmap_block_status *bbs;

			bbs = sector_to_bitmap_block(ic, dio->range.logical_sector);
			spin_lock(&bbs->bio_queue_lock);
			bio_list_add(&bbs->bio_queue, bio);
			spin_unlock(&bbs->bio_queue_lock);
			queue_work(ic->writer_wq, &bbs->work);
			return;
		}
	}

	dio->in_flight = (atomic_t)ATOMIC_INIT(2);

	if (need_sync_io) {
		init_completion(&read_comp);
		dio->completion = &read_comp;
	} else
		dio->completion = NULL;

	dm_bio_record(&dio->bio_details, bio);
	bio_set_dev(bio, ic->dev->bdev);
	bio->bi_integrity = NULL;
	bio->bi_opf &= ~REQ_INTEGRITY;
	bio->bi_end_io = integrity_end_io;
	bio->bi_iter.bi_size = dio->range.n_sectors << SECTOR_SHIFT;

	if (unlikely(dio->op == REQ_OP_DISCARD) && likely(ic->mode != 'D')) {
		integrity_metadata(&dio->work);
		dm_integrity_flush_buffers(ic, false);

		dio->in_flight = (atomic_t)ATOMIC_INIT(1);
		dio->completion = NULL;

		submit_bio_noacct(bio);

		return;
	}

	submit_bio_noacct(bio);

	if (need_sync_io) {
		wait_for_completion_io(&read_comp);
		if (ic->sb->flags & cpu_to_le32(SB_FLAG_RECALCULATING) &&
		    dio->range.logical_sector + dio->range.n_sectors > le64_to_cpu(ic->sb->recalc_sector))
			goto skip_check;
		if (ic->mode == 'B') {
			if (!block_bitmap_op(ic, ic->recalc_bitmap, dio->range.logical_sector,
					     dio->range.n_sectors, BITMAP_OP_TEST_ALL_CLEAR))
				goto skip_check;
		}

		if (likely(!bio->bi_status))
			integrity_metadata(&dio->work);
		else
skip_check:
			dec_in_flight(dio);

	} else {
		INIT_WORK(&dio->work, integrity_metadata);
		queue_work(ic->metadata_wq, &dio->work);
	}

	return;

journal_read_write:
	if (unlikely(__journal_read_write(dio, bio, journal_section, journal_entry)))
		goto lock_retry;

	do_endio_flush(ic, dio);
}


static void integrity_bio_wait(struct work_struct *w)
{
	struct dm_integrity_io *dio = container_of(w, struct dm_integrity_io, work);

	dm_integrity_map_continue(dio, false);
}

static void pad_uncommitted(struct dm_integrity_c *ic)
{
	if (ic->free_section_entry) {
		ic->free_sectors -= ic->journal_section_entries - ic->free_section_entry;
		ic->free_section_entry = 0;
		ic->free_section++;
		wraparound_section(ic, &ic->free_section);
		ic->n_uncommitted_sections++;
	}
	if (WARN_ON(ic->journal_sections * ic->journal_section_entries !=
		    (ic->n_uncommitted_sections + ic->n_committed_sections) *
		    ic->journal_section_entries + ic->free_sectors)) {
		DMCRIT("journal_sections %u, journal_section_entries %u, "
		       "n_uncommitted_sections %u, n_committed_sections %u, "
		       "journal_section_entries %u, free_sectors %u",
		       ic->journal_sections, ic->journal_section_entries,
		       ic->n_uncommitted_sections, ic->n_committed_sections,
		       ic->journal_section_entries, ic->free_sectors);
	}
}

static void integrity_commit(struct work_struct *w)
{
	struct dm_integrity_c *ic = container_of(w, struct dm_integrity_c, commit_work);
	unsigned commit_start, commit_sections;
	unsigned i, j, n;
	struct bio *flushes;

	del_timer(&ic->autocommit_timer);

	spin_lock_irq(&ic->endio_wait.lock);
	flushes = bio_list_get(&ic->flush_bio_list);
	if (unlikely(ic->mode != 'J')) {
		spin_unlock_irq(&ic->endio_wait.lock);
		dm_integrity_flush_buffers(ic, true);
		goto release_flush_bios;
	}

	pad_uncommitted(ic);
	commit_start = ic->uncommitted_section;
	commit_sections = ic->n_uncommitted_sections;
	spin_unlock_irq(&ic->endio_wait.lock);

	if (!commit_sections)
		goto release_flush_bios;

	i = commit_start;
	for (n = 0; n < commit_sections; n++) {
		for (j = 0; j < ic->journal_section_entries; j++) {
			struct journal_entry *je;
			je = access_journal_entry(ic, i, j);
			io_wait_event(ic->copy_to_journal_wait, !journal_entry_is_inprogress(je));
		}
		for (j = 0; j < ic->journal_section_sectors; j++) {
			struct journal_sector *js;
			js = access_journal(ic, i, j);
			js->commit_id = dm_integrity_commit_id(ic, i, j, ic->commit_seq);
		}
		i++;
		if (unlikely(i >= ic->journal_sections))
			ic->commit_seq = next_commit_seq(ic->commit_seq);
		wraparound_section(ic, &i);
	}
	smp_rmb();

	write_journal(ic, commit_start, commit_sections);

	spin_lock_irq(&ic->endio_wait.lock);
	ic->uncommitted_section += commit_sections;
	wraparound_section(ic, &ic->uncommitted_section);
	ic->n_uncommitted_sections -= commit_sections;
	ic->n_committed_sections += commit_sections;
	spin_unlock_irq(&ic->endio_wait.lock);

	if (READ_ONCE(ic->free_sectors) <= ic->free_sectors_threshold)
		queue_work(ic->writer_wq, &ic->writer_work);

release_flush_bios:
	while (flushes) {
		struct bio *next = flushes->bi_next;
		flushes->bi_next = NULL;
		do_endio(ic, flushes);
		flushes = next;
	}
}

static void complete_copy_from_journal(unsigned long error, void *context)
{
	struct journal_io *io = context;
	struct journal_completion *comp = io->comp;
	struct dm_integrity_c *ic = comp->ic;
	remove_range(ic, &io->range);
	mempool_free(io, &ic->journal_io_mempool);
	if (unlikely(error != 0))
		dm_integrity_io_error(ic, "copying from journal", -EIO);
	complete_journal_op(comp);
}

static void restore_last_bytes(struct dm_integrity_c *ic, struct journal_sector *js,
			       struct journal_entry *je)
{
	unsigned s = 0;
	do {
		js->commit_id = je->last_bytes[s];
		js++;
	} while (++s < ic->sectors_per_block);
}

static void do_journal_write(struct dm_integrity_c *ic, unsigned write_start,
			     unsigned write_sections, bool from_replay)
{
	unsigned i, j, n;
	struct journal_completion comp;
	struct blk_plug plug;

	blk_start_plug(&plug);

	comp.ic = ic;
	comp.in_flight = (atomic_t)ATOMIC_INIT(1);
	init_completion(&comp.comp);

	i = write_start;
	for (n = 0; n < write_sections; n++, i++, wraparound_section(ic, &i)) {
#ifndef INTERNAL_VERIFY
		if (unlikely(from_replay))
#endif
			rw_section_mac(ic, i, false);
		for (j = 0; j < ic->journal_section_entries; j++) {
			struct journal_entry *je = access_journal_entry(ic, i, j);
			sector_t sec, area, offset;
			unsigned k, l, next_loop;
			sector_t metadata_block;
			unsigned metadata_offset;
			struct journal_io *io;

			if (journal_entry_is_unused(je))
				continue;
			BUG_ON(unlikely(journal_entry_is_inprogress(je)) && !from_replay);
			sec = journal_entry_get_sector(je);
			if (unlikely(from_replay)) {
				if (unlikely(sec & (unsigned)(ic->sectors_per_block - 1))) {
					dm_integrity_io_error(ic, "invalid sector in journal", -EIO);
					sec &= ~(sector_t)(ic->sectors_per_block - 1);
				}
			}
			if (unlikely(sec >= ic->provided_data_sectors))
				continue;
			get_area_and_offset(ic, sec, &area, &offset);
			restore_last_bytes(ic, access_journal_data(ic, i, j), je);
			for (k = j + 1; k < ic->journal_section_entries; k++) {
				struct journal_entry *je2 = access_journal_entry(ic, i, k);
				sector_t sec2, area2, offset2;
				if (journal_entry_is_unused(je2))
					break;
				BUG_ON(unlikely(journal_entry_is_inprogress(je2)) && !from_replay);
				sec2 = journal_entry_get_sector(je2);
				if (unlikely(sec2 >= ic->provided_data_sectors))
					break;
				get_area_and_offset(ic, sec2, &area2, &offset2);
				if (area2 != area || offset2 != offset + ((k - j) << ic->sb->log2_sectors_per_block))
					break;
				restore_last_bytes(ic, access_journal_data(ic, i, k), je2);
			}
			next_loop = k - 1;

			io = mempool_alloc(&ic->journal_io_mempool, GFP_NOIO);
			io->comp = &comp;
			io->range.logical_sector = sec;
			io->range.n_sectors = (k - j) << ic->sb->log2_sectors_per_block;

			spin_lock_irq(&ic->endio_wait.lock);
			add_new_range_and_wait(ic, &io->range);

			if (likely(!from_replay)) {
				struct journal_node *section_node = &ic->journal_tree[i * ic->journal_section_entries];

				/* don't write if there is newer committed sector */
				while (j < k && find_newer_committed_node(ic, &section_node[j])) {
					struct journal_entry *je2 = access_journal_entry(ic, i, j);

					journal_entry_set_unused(je2);
					remove_journal_node(ic, &section_node[j]);
					j++;
					sec += ic->sectors_per_block;
					offset += ic->sectors_per_block;
				}
				while (j < k && find_newer_committed_node(ic, &section_node[k - 1])) {
					struct journal_entry *je2 = access_journal_entry(ic, i, k - 1);

					journal_entry_set_unused(je2);
					remove_journal_node(ic, &section_node[k - 1]);
					k--;
				}
				if (j == k) {
					remove_range_unlocked(ic, &io->range);
					spin_unlock_irq(&ic->endio_wait.lock);
					mempool_free(io, &ic->journal_io_mempool);
					goto skip_io;
				}
				for (l = j; l < k; l++) {
					remove_journal_node(ic, &section_node[l]);
				}
			}
			spin_unlock_irq(&ic->endio_wait.lock);

			metadata_block = get_metadata_sector_and_offset(ic, area, offset, &metadata_offset);
			for (l = j; l < k; l++) {
				int r;
				struct journal_entry *je2 = access_journal_entry(ic, i, l);

				if (
#ifndef INTERNAL_VERIFY
				    unlikely(from_replay) &&
#endif
				    ic->internal_hash) {
					char test_tag[max_t(size_t, HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)];

					integrity_sector_checksum(ic, sec + ((l - j) << ic->sb->log2_sectors_per_block),
								  (char *)access_journal_data(ic, i, l), test_tag);
					if (unlikely(memcmp(test_tag, journal_entry_tag(ic, je2), ic->tag_size))) {
						dm_integrity_io_error(ic, "tag mismatch when replaying journal", -EILSEQ);
						dm_audit_log_target(DM_MSG_PREFIX, "integrity-replay-journal", ic->ti, 0);
					}
				}

				journal_entry_set_unused(je2);
				r = dm_integrity_rw_tag(ic, journal_entry_tag(ic, je2), &metadata_block, &metadata_offset,
							ic->tag_size, TAG_WRITE);
				if (unlikely(r)) {
					dm_integrity_io_error(ic, "reading tags", r);
				}
			}

			atomic_inc(&comp.in_flight);
			copy_from_journal(ic, i, j << ic->sb->log2_sectors_per_block,
					  (k - j) << ic->sb->log2_sectors_per_block,
					  get_data_sector(ic, area, offset),
					  complete_copy_from_journal, io);
skip_io:
			j = next_loop;
		}
	}

	dm_bufio_write_dirty_buffers_async(ic->bufio);

	blk_finish_plug(&plug);

	complete_journal_op(&comp);
	wait_for_completion_io(&comp.comp);

	dm_integrity_flush_buffers(ic, true);
}

static void integrity_writer(struct work_struct *w)
{
	struct dm_integrity_c *ic = container_of(w, struct dm_integrity_c, writer_work);
	unsigned write_start, write_sections;

	unsigned prev_free_sectors;

	/* the following test is not needed, but it tests the replay code */
	if (unlikely(dm_post_suspending(ic->ti)) && !ic->meta_dev)
		return;

	spin_lock_irq(&ic->endio_wait.lock);
	write_start = ic->committed_section;
	write_sections = ic->n_committed_sections;
	spin_unlock_irq(&ic->endio_wait.lock);

	if (!write_sections)
		return;

	do_journal_write(ic, write_start, write_sections, false);

	spin_lock_irq(&ic->endio_wait.lock);

	ic->committed_section += write_sections;
	wraparound_section(ic, &ic->committed_section);
	ic->n_committed_sections -= write_sections;

	prev_free_sectors = ic->free_sectors;
	ic->free_sectors += write_sections * ic->journal_section_entries;
	if (unlikely(!prev_free_sectors))
		wake_up_locked(&ic->endio_wait);

	spin_unlock_irq(&ic->endio_wait.lock);
}

static void recalc_write_super(struct dm_integrity_c *ic)
{
	int r;

	dm_integrity_flush_buffers(ic, false);
	if (dm_integrity_failed(ic))
		return;

	r = sync_rw_sb(ic, REQ_OP_WRITE, 0);
	if (unlikely(r))
		dm_integrity_io_error(ic, "writing superblock", r);
}

static void integrity_recalc(struct work_struct *w)
{
	struct dm_integrity_c *ic = container_of(w, struct dm_integrity_c, recalc_work);
	struct dm_integrity_range range;
	struct dm_io_request io_req;
	struct dm_io_region io_loc;
	sector_t area, offset;
	sector_t metadata_block;
	unsigned metadata_offset;
	sector_t logical_sector, n_sectors;
	__u8 *t;
	unsigned i;
	int r;
	unsigned super_counter = 0;

	DEBUG_print("start recalculation... (position %llx)\n", le64_to_cpu(ic->sb->recalc_sector));

	spin_lock_irq(&ic->endio_wait.lock);

next_chunk:

	if (unlikely(dm_post_suspending(ic->ti)))
		goto unlock_ret;

	range.logical_sector = le64_to_cpu(ic->sb->recalc_sector);
	if (unlikely(range.logical_sector >= ic->provided_data_sectors)) {
		if (ic->mode == 'B') {
			block_bitmap_op(ic, ic->recalc_bitmap, 0, ic->provided_data_sectors, BITMAP_OP_CLEAR);
			DEBUG_print("queue_delayed_work: bitmap_flush_work\n");
			queue_delayed_work(ic->commit_wq, &ic->bitmap_flush_work, 0);
		}
		goto unlock_ret;
	}

	get_area_and_offset(ic, range.logical_sector, &area, &offset);
	range.n_sectors = min((sector_t)RECALC_SECTORS, ic->provided_data_sectors - range.logical_sector);
	if (!ic->meta_dev)
		range.n_sectors = min(range.n_sectors, ((sector_t)1U << ic->sb->log2_interleave_sectors) - (unsigned)offset);

	add_new_range_and_wait(ic, &range);
	spin_unlock_irq(&ic->endio_wait.lock);
	logical_sector = range.logical_sector;
	n_sectors = range.n_sectors;

	if (ic->mode == 'B') {
		if (block_bitmap_op(ic, ic->recalc_bitmap, logical_sector, n_sectors, BITMAP_OP_TEST_ALL_CLEAR)) {
			goto advance_and_next;
		}
		while (block_bitmap_op(ic, ic->recalc_bitmap, logical_sector,
				       ic->sectors_per_block, BITMAP_OP_TEST_ALL_CLEAR)) {
			logical_sector += ic->sectors_per_block;
			n_sectors -= ic->sectors_per_block;
			cond_resched();
		}
		while (block_bitmap_op(ic, ic->recalc_bitmap, logical_sector + n_sectors - ic->sectors_per_block,
				       ic->sectors_per_block, BITMAP_OP_TEST_ALL_CLEAR)) {
			n_sectors -= ic->sectors_per_block;
			cond_resched();
		}
		get_area_and_offset(ic, logical_sector, &area, &offset);
	}

	DEBUG_print("recalculating: %llx, %llx\n", logical_sector, n_sectors);

	if (unlikely(++super_counter == RECALC_WRITE_SUPER)) {
		recalc_write_super(ic);
		if (ic->mode == 'B') {
			queue_delayed_work(ic->commit_wq, &ic->bitmap_flush_work, ic->bitmap_flush_interval);
		}
		super_counter = 0;
	}

	if (unlikely(dm_integrity_failed(ic)))
		goto err;

	io_req.bi_op = REQ_OP_READ;
	io_req.bi_op_flags = 0;
	io_req.mem.type = DM_IO_VMA;
	io_req.mem.ptr.addr = ic->recalc_buffer;
	io_req.notify.fn = NULL;
	io_req.client = ic->io;
	io_loc.bdev = ic->dev->bdev;
	io_loc.sector = get_data_sector(ic, area, offset);
	io_loc.count = n_sectors;

	r = dm_io(&io_req, 1, &io_loc, NULL);
	if (unlikely(r)) {
		dm_integrity_io_error(ic, "reading data", r);
		goto err;
	}

	t = ic->recalc_tags;
	for (i = 0; i < n_sectors; i += ic->sectors_per_block) {
		integrity_sector_checksum(ic, logical_sector + i, ic->recalc_buffer + (i << SECTOR_SHIFT), t);
		t += ic->tag_size;
	}

	metadata_block = get_metadata_sector_and_offset(ic, area, offset, &metadata_offset);

	r = dm_integrity_rw_tag(ic, ic->recalc_tags, &metadata_block, &metadata_offset, t - ic->recalc_tags, TAG_WRITE);
	if (unlikely(r)) {
		dm_integrity_io_error(ic, "writing tags", r);
		goto err;
	}

	if (ic->mode == 'B') {
		sector_t start, end;
		start = (range.logical_sector >>
			 (ic->sb->log2_sectors_per_block + ic->log2_blocks_per_bitmap_bit)) <<
			(ic->sb->log2_sectors_per_block + ic->log2_blocks_per_bitmap_bit);
		end = ((range.logical_sector + range.n_sectors) >>
		       (ic->sb->log2_sectors_per_block + ic->log2_blocks_per_bitmap_bit)) <<
			(ic->sb->log2_sectors_per_block + ic->log2_blocks_per_bitmap_bit);
		block_bitmap_op(ic, ic->recalc_bitmap, start, end - start, BITMAP_OP_CLEAR);
	}

advance_and_next:
	cond_resched();

	spin_lock_irq(&ic->endio_wait.lock);
	remove_range_unlocked(ic, &range);
	ic->sb->recalc_sector = cpu_to_le64(range.logical_sector + range.n_sectors);
	goto next_chunk;

err:
	remove_range(ic, &range);
	return;

unlock_ret:
	spin_unlock_irq(&ic->endio_wait.lock);

	recalc_write_super(ic);
}

static void bitmap_block_work(struct work_struct *w)
{
	struct bitmap_block_status *bbs = container_of(w, struct bitmap_block_status, work);
	struct dm_integrity_c *ic = bbs->ic;
	struct bio *bio;
	struct bio_list bio_queue;
	struct bio_list waiting;

	bio_list_init(&waiting);

	spin_lock(&bbs->bio_queue_lock);
	bio_queue = bbs->bio_queue;
	bio_list_init(&bbs->bio_queue);
	spin_unlock(&bbs->bio_queue_lock);

	while ((bio = bio_list_pop(&bio_queue))) {
		struct dm_integrity_io *dio;

		dio = dm_per_bio_data(bio, sizeof(struct dm_integrity_io));

		if (block_bitmap_op(ic, ic->may_write_bitmap, dio->range.logical_sector,
				    dio->range.n_sectors, BITMAP_OP_TEST_ALL_SET)) {