text: /*
   * 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 <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>
  
  #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			8192
  #define RECALC_WRITE_SUPER		16
  #define BITMAP_BLOCK_SIZE		4096	/* don't change it */
  #define BITMAP_FLUSH_INTERVAL		(10 * HZ)
  
  /*
   * 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_SECTORS			8
  #define MAX_SECTORS_PER_BLOCK		8
  
  struct superblock {
  	__u8 magic[8];
  	__u8 version;
  	__u8 log2_interleave_sectors;
  	__u16 integrity_tag_size;
  	__u32 journal_sections;
  	__u64 provided_data_sectors;	/* userspace uses this value */
  	__u32 flags;
  	__u8 log2_sectors_per_block;
  	__u8 log2_blocks_per_bitmap_bit;
  	__u8 pad[2];
  	__u64 recalc_sector;
  };
  
  #define SB_FLAG_HAVE_JOURNAL_MAC	0x1
  #define SB_FLAG_RECALCULATING		0x2
  #define SB_FLAG_DIRTY_BITMAP		0x4
  
  #define	JOURNAL_ENTRY_ROUNDUP		8
  
  typedef __u64 commit_id_t;
  #define JOURNAL_MAC_PER_SECTOR		8
  
  struct journal_entry {
  	union {
  		struct {
  			__u32 sector_lo;
  			__u32 sector_hi;
  		} s;
  		__u64 sector;
  	} u;
  	commit_id_t last_bytes[0];
  	/* __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 suspending;
  
  	int failed;
  
  	struct crypto_shash *internal_hash;
  
  	/* 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;
  
  	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;
  
  	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;
  	bool write;
  	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 gendisk *orig_bi_disk;
  	u8 orig_bi_partno;
  	bio_end_io_t *orig_bi_end_io;
  	struct bio_integrity_payload *orig_bi_integrity;
  	struct bvec_iter orig_bi_iter;
  };
  
  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
  
  /*
   * 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,
  };
  
  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 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->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 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;
  
  	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;
  
  	return dm_io(&io_req, 1, &io_loc, NULL);
  }
  
  #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)",
  			(unsigned long long)sector,
  			(unsigned long long)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)) {
  		dm_integrity_io_error(ic, "crypto_shash_init", 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)) {
  			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)) {
  			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)) {
  			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);
  		}
  	}
  }
  
  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)
  {
  	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) {
  			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 (unlikely(memcmp(dp, tag, to_copy))) {
  				unsigned i;
  
  				for (i = 0; i < to_copy; i++) {
  					if (dp[i] != tag[i])
  						break;
  					total_size--;
  				}
  				dm_bufio_release(b);
  				return total_size;
  			}
  		}
  		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;
  		}
  		total_size -= to_copy;
  	} while (unlikely(total_size));
  
  	return 0;
  }
  
  static void dm_integrity_flush_buffers(struct dm_integrity_c *ic)
  {
  	int r;
  	r = dm_bufio_write_dirty_buffers(ic->bufio);
  	if (unlikely(r))
  		dm_integrity_io_error(ic, "writing tags", r);
  }
  
  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 (unlikely(dio->write))
  			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->wait_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));
  
  	bio->bi_iter = dio->orig_bi_iter;
  	bio->bi_disk = dio->orig_bi_disk;
  	bio->bi_partno = dio->orig_bi_partno;
  	if (dio->orig_bi_integrity) {
  		bio->bi_integrity = dio->orig_bi_integrity;
  		bio->bi_opf |= REQ_INTEGRITY;
  	}
  	bio->bi_end_io = dio->orig_bi_end_io;
  
  	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)
  {
  	__u64 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;
  	}
  
  	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[HASH_MAX_DIGESTSIZE];
  		unsigned sectors_to_process = dio->range.n_sectors;
  		sector_t sector = dio->range.logical_sector;
  
  		if (unlikely(ic->mode == 'R'))
  			goto skip_io;
  
  		checksums = kmalloc((PAGE_SIZE >> SECTOR_SHIFT >> ic->sb->log2_sectors_per_block) * ic->tag_size + extra_space,
  				    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;
  			}
  		}
  
  		__bio_for_each_segment(bv, bio, iter, dio->orig_bi_iter) {
  			unsigned pos;
  			char *mem, *checksums_ptr;
  
  again:
  			mem = (char *)kmap_atomic(bv.bv_page) + bv.bv_offset;
  			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_atomic(mem);
  
  			r = dm_integrity_rw_tag(ic, checksums, &dio->metadata_block, &dio->metadata_offset,
  						checksums_ptr - checksums, !dio->write ? TAG_CMP : TAG_WRITE);
  			if (unlikely(r)) {
  				if (r > 0) {
  					DMERR_LIMIT("Checksum failed at sector 0x%llx",
  						    (unsigned long long)(sector - ((r + ic->tag_size - 1) / ic->tag_size)));
  					r = -EILSEQ;
  					atomic64_inc(&ic->number_of_mismatches);
  				}
  				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->orig_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 = lowmem_page_address(biv.bv_page) + biv.bv_offset;
  				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->write ? 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;
  
  	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->write = bio_op(bio) == REQ_OP_WRITE;
  	dio->fua = dio->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",
  		      (unsigned long long)dio->range.logical_sector, bio_sectors(bio),
  		      (unsigned long long)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,
  		      (unsigned long long)dio->range.logical_sector, bio_sectors(bio));
  		return DM_MAPIO_KILL;
  	}
  
  	if (ic->sectors_per_block > 1) {
  		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->write))
  		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 = kmap_atomic(bv.bv_page);
  		if (likely(dio->write))
  			flush_dcache_page(bv.bv_page);
  
  		do {
  			struct journal_entry *je = access_journal_entry(ic, journal_section, journal_entry);
  
  			if (unlikely(!dio->write)) {
  				struct journal_sector *js;
  				char *mem_ptr;
  				unsigned s;
  
  				if (unlikely(journal_entry_is_inprogress(je))) {
  					flush_dcache_page(bv.bv_page);
  					kunmap_atomic(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(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",
  							    (unsigned long long)logical_sector);
  					}
  				}
  #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 = lowmem_page_address(biv.bv_page) + biv.bv_offset;
  					if (likely(dio->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->write))
  						memset(tag_ptr, 0, tag_todo);
  				}
  			}
  
  			if (likely(dio->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->write))
  			flush_dcache_page(bv.bv_page);
  		kunmap_atomic(mem);
  	} while (n_sectors);
  
  	if (likely(dio->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 need_sync_io = ic->internal_hash && !dio->write;
  
  	if (need_sync_io && from_map) {
  		INIT_WORK(&dio->work, integrity_bio_wait);
  		queue_work(ic->metadata_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 (likely(ic->mode == 'J')) {
  		if (dio->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;
  		}
  		wait_and_add_new_range(ic, &dio->range);
  	}
  	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->write) {
  		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;
  
  	dio->orig_bi_iter = bio->bi_iter;
  
  	dio->orig_bi_disk = bio->bi_disk;
  	dio->orig_bi_partno = bio->bi_partno;
  	bio_set_dev(bio, ic->dev->bdev);
  
  	dio->orig_bi_integrity = bio_integrity(bio);
  	bio->bi_integrity = NULL;
  	bio->bi_opf &= ~REQ_INTEGRITY;
  
  	dio->orig_bi_end_io = bio->bi_end_io;
  	bio->bi_end_io = integrity_end_io;
  
  	bio->bi_iter.bi_size = dio->range.n_sectors << SECTOR_SHIFT;
  	generic_make_request(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);
  		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);
  				}
  			}
  			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);
  				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);
  				}
  
  				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);
  }
  
  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 (READ_ONCE(ic->suspending) && !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);
  	if (dm_integrity_failed(ic))
  		return;
  
  	sb_set_version(ic);
  	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(READ_ONCE(ic->suspending)))
  		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') {
  			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: %lx, %lx\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;
  	}
  
  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)) {
  			remove_range(ic, &dio->range);
  			INIT_WORK(&dio->work, integrity_bio_wait);
  			queue_work(ic->wait_wq, &dio->work);
  		} else {
  			block_bitmap_op(ic, ic->journal, dio->range.logical_sector,
  					dio->range.n_sectors, BITMAP_OP_SET);
  			bio_list_add(&waiting, bio);
  		}
  	}
  
  	if (bio_list_empty(&waiting))
  		return;
  
  	rw_journal_sectors(ic, REQ_OP_WRITE, REQ_FUA | REQ_SYNC,
  			   bbs->idx * (BITMAP_BLOCK_SIZE >> SECTOR_SHIFT),
  			   BITMAP_BLOCK_SIZE >> SECTOR_SHIFT, NULL);
  
  	while ((bio = bio_list_pop(&waiting))) {
  		struct dm_integrity_io *dio = dm_per_bio_data(bio, sizeof(struct dm_integrity_io));
  
  		block_bitmap_op(ic, ic->may_write_bitmap, dio->range.logical_sector,
  				dio->range.n_sectors, BITMAP_OP_SET);
  
  		remove_range(ic, &dio->range);
  		INIT_WORK(&dio->work, integrity_bio_wait);
  		queue_work(ic->wait_wq, &dio->work);
  	}
  
  	queue_delayed_work(ic->commit_wq, &ic->bitmap_flush_work, ic->bitmap_flush_interval);
  }
  
  static void bitmap_flush_work(struct work_struct *work)
  {
  	struct dm_integrity_c *ic = container_of(work, struct dm_integrity_c, bitmap_flush_work.work);
  	struct dm_integrity_range range;
  	unsigned long limit;
  	struct bio *bio;
  
  	dm_integrity_flush_buffers(ic);
  
  	range.logical_sector = 0;
  	range.n_sectors = ic->provided_data_sectors;
  
  	spin_lock_irq(&ic->endio_wait.lock);
  	add_new_range_and_wait(ic, &range);
  	spin_unlock_irq(&ic->endio_wait.lock);
  
  	dm_integrity_flush_buffers(ic);
  	if (ic->meta_dev)
  		blkdev_issue_flush(ic->dev->bdev, GFP_NOIO, NULL);
  
  	limit = ic->provided_data_sectors;
  	if (ic->sb->flags & cpu_to_le32(SB_FLAG_RECALCULATING)) {
  		limit = le64_to_cpu(ic->sb->recalc_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);
  	}
  	/*DEBUG_print("zeroing journal\n");*/
  	block_bitmap_op(ic, ic->journal, 0, limit, BITMAP_OP_CLEAR);
  	block_bitmap_op(ic, ic->may_write_bitmap, 0, limit, BITMAP_OP_CLEAR);
  
  	rw_journal_sectors(ic, REQ_OP_WRITE, REQ_FUA | REQ_SYNC, 0,
  			   ic->n_bitmap_blocks * (BITMAP_BLOCK_SIZE >> SECTOR_SHIFT), NULL);
  
  	spin_lock_irq(&ic->endio_wait.lock);
  	remove_range_unlocked(ic, &range);
  	while (unlikely((bio = bio_list_pop(&ic->synchronous_bios)) != NULL)) {
  		bio_endio(bio);
  		spin_unlock_irq(&ic->endio_wait.lock);
  		spin_lock_irq(&ic->endio_wait.lock);
  	}
  	spin_unlock_irq(&ic->endio_wait.lock);
  }
  
  
  static void init_journal(struct dm_integrity_c *ic, unsigned start_section,
  			 unsigned n_sections, unsigned char commit_seq)
  {
  	unsigned i, j, n;
  
  	if (!n_sections)
  		return;
  
  	for (n = 0; n < n_sections; n++) {
  		i = start_section + n;
  		wraparound_section(ic, &i);
  		for (j = 0; j < ic->journal_section_sectors; j++) {
  			struct journal_sector *js = access_journal(ic, i, j);
  			memset(&js->entries, 0, JOURNAL_SECTOR_DATA);
  			js->commit_id = dm_integrity_commit_id(ic, i, j, commit_seq);
  		}
  		for (j = 0; j < ic->journal_section_entries; j++) {
  			struct journal_entry *je = access_journal_entry(ic, i, j);
  			journal_entry_set_unused(je);
  		}
  	}
  
  	write_journal(ic, start_section, n_sections);
  }
  
  static int find_commit_seq(struct dm_integrity_c *ic, unsigned i, unsigned j, commit_id_t id)
  {
  	unsigned char k;
  	for (k = 0; k < N_COMMIT_IDS; k++) {
  		if (dm_integrity_commit_id(ic, i, j, k) == id)
  			return k;
  	}
  	dm_integrity_io_error(ic, "journal commit id", -EIO);
  	return -EIO;
  }
  
  static void replay_journal(struct dm_integrity_c *ic)
  {
  	unsigned i, j;
  	bool used_commit_ids[N_COMMIT_IDS];
  	unsigned max_commit_id_sections[N_COMMIT_IDS];
  	unsigned write_start, write_sections;
  	unsigned continue_section;
  	bool journal_empty;
  	unsigned char unused, last_used, want_commit_seq;
  
  	if (ic->mode == 'R')
  		return;
  
  	if (ic->journal_uptodate)
  		return;
  
  	last_used = 0;
  	write_start = 0;
  
  	if (!ic->just_formatted) {
  		DEBUG_print("reading journal\n");
  		rw_journal(ic, REQ_OP_READ, 0, 0, ic->journal_sections, NULL);
  		if (ic->journal_io)
  			DEBUG_bytes(lowmem_page_address(ic->journal_io[0].page), 64, "read journal");
  		if (ic->journal_io) {
  			struct journal_completion crypt_comp;
  			crypt_comp.ic = ic;
  			init_completion(&crypt_comp.comp);
  			crypt_comp.in_flight = (atomic_t)ATOMIC_INIT(0);
  			encrypt_journal(ic, false, 0, ic->journal_sections, &crypt_comp);
  			wait_for_completion(&crypt_comp.comp);
  		}
  		DEBUG_bytes(lowmem_page_address(ic->journal[0].page), 64, "decrypted journal");
  	}
  
  	if (dm_integrity_failed(ic))
  		goto clear_journal;
  
  	journal_empty = true;
  	memset(used_commit_ids, 0, sizeof used_commit_ids);
  	memset(max_commit_id_sections, 0, sizeof max_commit_id_sections);
  	for (i = 0; i < ic->journal_sections; i++) {
  		for (j = 0; j < ic->journal_section_sectors; j++) {
  			int k;
  			struct journal_sector *js = access_journal(ic, i, j);
  			k = find_commit_seq(ic, i, j, js->commit_id);
  			if (k < 0)
  				goto clear_journal;
  			used_commit_ids[k] = true;
  			max_commit_id_sections[k] = i;
  		}
  		if (journal_empty) {
  			for (j = 0; j < ic->journal_section_entries; j++) {
  				struct journal_entry *je = access_journal_entry(ic, i, j);
  				if (!journal_entry_is_unused(je)) {
  					journal_empty = false;
  					break;
  				}
  			}
  		}
  	}
  
  	if (!used_commit_ids[N_COMMIT_IDS - 1]) {
  		unused = N_COMMIT_IDS - 1;
  		while (unused && !used_commit_ids[unused - 1])
  			unused--;
  	} else {
  		for (unused = 0; unused < N_COMMIT_IDS; unused++)
  			if (!used_commit_ids[unused])
  				break;
  		if (unused == N_COMMIT_IDS) {
  			dm_integrity_io_error(ic, "journal commit ids", -EIO);
  			goto clear_journal;
  		}
  	}
  	DEBUG_print("first unused commit seq %d [%d,%d,%d,%d]\n",
  		    unused, used_commit_ids[0], used_commit_ids[1],
  		    used_commit_ids[2], used_commit_ids[3]);
  
  	last_used = prev_commit_seq(unused);
  	want_commit_seq = prev_commit_seq(last_used);
  
  	if (!used_commit_ids[want_commit_seq] && used_commit_ids[prev_commit_seq(want_commit_seq)])
  		journal_empty = true;
  
  	write_start = max_commit_id_sections[last_used] + 1;
  	if (unlikely(write_start >= ic->journal_sections))
  		want_commit_seq = next_commit_seq(want_commit_seq);
  	wraparound_section(ic, &write_start);
  
  	i = write_start;
  	for (write_sections = 0; write_sections < ic->journal_sections; write_sections++) {
  		for (j = 0; j < ic->journal_section_sectors; j++) {
  			struct journal_sector *js = access_journal(ic, i, j);
  
  			if (js->commit_id != dm_integrity_commit_id(ic, i, j, want_commit_seq)) {
  				/*
  				 * This could be caused by crash during writing.
  				 * We won't replay the inconsistent part of the
  				 * journal.
  				 */
  				DEBUG_print("commit id mismatch at position (%u, %u): %d != %d\n",
  					    i, j, find_commit_seq(ic, i, j, js->commit_id), want_commit_seq);
  				goto brk;
  			}
  		}
  		i++;
  		if (unlikely(i >= ic->journal_sections))
  			want_commit_seq = next_commit_seq(want_commit_seq);
  		wraparound_section(ic, &i);
  	}
  brk:
  
  	if (!journal_empty) {
  		DEBUG_print("replaying %u sections, starting at %u, commit seq %d\n",
  			    write_sections, write_start, want_commit_seq);
  		do_journal_write(ic, write_start, write_sections, true);
  	}
  
  	if (write_sections == ic->journal_sections && (ic->mode == 'J' || journal_empty)) {
  		continue_section = write_start;
  		ic->commit_seq = want_commit_seq;
  		DEBUG_print("continuing from section %u, commit seq %d\n", write_start, ic->commit_seq);
  	} else {
  		unsigned s;
  		unsigned char erase_seq;
  clear_journal:
  		DEBUG_print("clearing journal\n");
  
  		erase_seq = prev_commit_seq(prev_commit_seq(last_used));
  		s = write_start;
  		init_journal(ic, s, 1, erase_seq);
  		s++;
  		wraparound_section(ic, &s);
  		if (ic->journal_sections >= 2) {
  			init_journal(ic, s, ic->journal_sections - 2, erase_seq);
  			s += ic->journal_sections - 2;
  			wraparound_section(ic, &s);
  			init_journal(ic, s, 1, erase_seq);
  		}
  
  		continue_section = 0;
  		ic->commit_seq = next_commit_seq(erase_seq);
  	}
  
  	ic->committed_section = continue_section;
  	ic->n_committed_sections = 0;
  
  	ic->uncommitted_section = continue_section;
  	ic->n_uncommitted_sections = 0;
  
  	ic->free_section = continue_section;
  	ic->free_section_entry = 0;
  	ic->free_sectors = ic->journal_entries;
  
  	ic->journal_tree_root = RB_ROOT;
  	for (i = 0; i < ic->journal_entries; i++)
  		init_journal_node(&ic->journal_tree[i]);
  }
  
  static void dm_integrity_enter_synchronous_mode(struct dm_integrity_c *ic)
  {
  	DEBUG_print("dm_integrity_enter_synchronous_mode\n");
  
  	if (ic->mode == 'B') {
  		ic->bitmap_flush_interval = msecs_to_jiffies(10) + 1;
  		ic->synchronous_mode = 1;
  
  		cancel_delayed_work_sync(&ic->bitmap_flush_work);
  		queue_delayed_work(ic->commit_wq, &ic->bitmap_flush_work, 0);
  		flush_workqueue(ic->commit_wq);
  	}
  }
  
  static int dm_integrity_reboot(struct notifier_block *n, unsigned long code, void *x)
  {
  	struct dm_integrity_c *ic = container_of(n, struct dm_integrity_c, reboot_notifier);
  
  	DEBUG_print("dm_integrity_reboot\n");
  
  	dm_integrity_enter_synchronous_mode(ic);
  
  	return NOTIFY_DONE;
  }
  
  static void dm_integrity_postsuspend(struct dm_target *ti)
  {
  	struct dm_integrity_c *ic = (struct dm_integrity_c *)ti->private;
  	int r;
  
  	WARN_ON(unregister_reboot_notifier(&ic->reboot_notifier));
  
  	del_timer_sync(&ic->autocommit_timer);
  
  	WRITE_ONCE(ic->suspending, 1);
  
  	if (ic->recalc_wq)
  		drain_workqueue(ic->recalc_wq);
  
  	if (ic->mode == 'B')
  		cancel_delayed_work_sync(&ic->bitmap_flush_work);
  
  	queue_work(ic->commit_wq, &ic->commit_work);
  	drain_workqueue(ic->commit_wq);
  
  	if (ic->mode == 'J') {
  		if (ic->meta_dev)
  			queue_work(ic->writer_wq, &ic->writer_work);
  		drain_workqueue(ic->writer_wq);
  		dm_integrity_flush_buffers(ic);
  	}
  
  	if (ic->mode == 'B') {
  		dm_integrity_flush_buffers(ic);
  #if 1
  		/* set to 0 to test bitmap replay code */
  		init_journal(ic, 0, ic->journal_sections, 0);
  		ic->sb->flags &= ~cpu_to_le32(SB_FLAG_DIRTY_BITMAP);
  		r = sync_rw_sb(ic, REQ_OP_WRITE, REQ_FUA);
  		if (unlikely(r))
  			dm_integrity_io_error(ic, "writing superblock", r);
  #endif
  	}
  
  	WRITE_ONCE(ic->suspending, 0);
  
  	BUG_ON(!RB_EMPTY_ROOT(&ic->in_progress));
  
  	ic->journal_uptodate = true;
  }
  
  static void dm_integrity_resume(struct dm_target *ti)
  {
  	struct dm_integrity_c *ic = (struct dm_integrity_c *)ti->private;
  	int r;
  	DEBUG_print("resume\n");
  
  	if (ic->sb->flags & cpu_to_le32(SB_FLAG_DIRTY_BITMAP)) {
  		DEBUG_print("resume dirty_bitmap\n");
  		rw_journal_sectors(ic, REQ_OP_READ, 0, 0,
  				   ic->n_bitmap_blocks * (BITMAP_BLOCK_SIZE >> SECTOR_SHIFT), NULL);
  		if (ic->mode == 'B') {
  			if (ic->sb->log2_blocks_per_bitmap_bit == ic->log2_blocks_per_bitmap_bit) {
  				block_bitmap_copy(ic, ic->recalc_bitmap, ic->journal);
  				block_bitmap_copy(ic, ic->may_write_bitmap, ic->journal);
  				if (!block_bitmap_op(ic, ic->journal, 0, ic->provided_data_sectors,
  						     BITMAP_OP_TEST_ALL_CLEAR)) {
  					ic->sb->flags |= cpu_to_le32(SB_FLAG_RECALCULATING);
  					ic->sb->recalc_sector = cpu_to_le64(0);
  				}
  			} else {
  				DEBUG_print("non-matching blocks_per_bitmap_bit: %u, %u\n",
  					    ic->sb->log2_blocks_per_bitmap_bit, ic->log2_blocks_per_bitmap_bit);
  				ic->sb->log2_blocks_per_bitmap_bit = ic->log2_blocks_per_bitmap_bit;
  				block_bitmap_op(ic, ic->recalc_bitmap, 0, ic->provided_data_sectors, BITMAP_OP_SET);
  				block_bitmap_op(ic, ic->may_write_bitmap, 0, ic->provided_data_sectors, BITMAP_OP_SET);
  				block_bitmap_op(ic, ic->journal, 0, ic->provided_data_sectors, BITMAP_OP_SET);
  				rw_journal_sectors(ic, REQ_OP_WRITE, REQ_FUA | REQ_SYNC, 0,
  						   ic->n_bitmap_blocks * (BITMAP_BLOCK_SIZE >> SECTOR_SHIFT), NULL);
  				ic->sb->flags |= cpu_to_le32(SB_FLAG_RECALCULATING);
  				ic->sb->recalc_sector = cpu_to_le64(0);
  			}
  		} else {
  			if (!(ic->sb->log2_blocks_per_bitmap_bit == ic->log2_blocks_per_bitmap_bit &&
  			      block_bitmap_op(ic, ic->journal, 0, ic->provided_data_sectors, BITMAP_OP_TEST_ALL_CLEAR))) {
  				ic->sb->flags |= cpu_to_le32(SB_FLAG_RECALCULATING);
  				ic->sb->recalc_sector = cpu_to_le64(0);
  			}
  			init_journal(ic, 0, ic->journal_sections, 0);
  			replay_journal(ic);
  			ic->sb->flags &= ~cpu_to_le32(SB_FLAG_DIRTY_BITMAP);
  		}
  		r = sync_rw_sb(ic, REQ_OP_WRITE, REQ_FUA);
  		if (unlikely(r))
  			dm_integrity_io_error(ic, "writing superblock", r);
  	} else {
  		replay_journal(ic);
  		if (ic->mode == 'B') {
  			int mode;
  			ic->sb->flags |= cpu_to_le32(SB_FLAG_DIRTY_BITMAP);
  			ic->sb->log2_blocks_per_bitmap_bit = ic->log2_blocks_per_bitmap_bit;
  			r = sync_rw_sb(ic, REQ_OP_WRITE, REQ_FUA);
  			if (unlikely(r))
  				dm_integrity_io_error(ic, "writing superblock", r);
  
  			mode = ic->recalculate_flag ? BITMAP_OP_SET : BITMAP_OP_CLEAR;
  			block_bitmap_op(ic, ic->journal, 0, ic->provided_data_sectors, mode);
  			block_bitmap_op(ic, ic->recalc_bitmap, 0, ic->provided_data_sectors, mode);
  			block_bitmap_op(ic, ic->may_write_bitmap, 0, ic->provided_data_sectors, mode);
  			rw_journal_sectors(ic, REQ_OP_WRITE, REQ_FUA | REQ_SYNC, 0,
  					   ic->n_bitmap_blocks * (BITMAP_BLOCK_SIZE >> SECTOR_SHIFT), NULL);
  		}
  	}
  
  	DEBUG_print("testing recalc: %x\n", ic->sb->flags);
  	if (ic->sb->flags & cpu_to_le32(SB_FLAG_RECALCULATING)) {
  		__u64 recalc_pos = le64_to_cpu(ic->sb->recalc_sector);
  		DEBUG_print("recalc pos: %lx / %lx\n", (long)recalc_pos, ic->provided_data_sectors);
  		if (recalc_pos < ic->provided_data_sectors) {
  			queue_work(ic->recalc_wq, &ic->recalc_work);
  		} else if (recalc_pos > ic->provided_data_sectors) {
  			ic->sb->recalc_sector = cpu_to_le64(ic->provided_data_sectors);
  			recalc_write_super(ic);
  		}
  	}
  
  	ic->reboot_notifier.notifier_call = dm_integrity_reboot;
  	ic->reboot_notifier.next = NULL;
  	ic->reboot_notifier.priority = INT_MAX - 1;	/* be notified after md and before hardware drivers */
  	WARN_ON(register_reboot_notifier(&ic->reboot_notifier));
  
  #if 0
  	/* set to 1 to stress test synchronous mode */
  	dm_integrity_enter_synchronous_mode(ic);
  #endif
  }
  
  static void dm_integrity_status(struct dm_target *ti, status_type_t type,
  				unsigned status_flags, char *result, unsigned maxlen)
  {
  	struct dm_integrity_c *ic = (struct dm_integrity_c *)ti->private;
  	unsigned arg_count;
  	size_t sz = 0;
  
  	switch (type) {
  	case STATUSTYPE_INFO:
  		DMEMIT("%llu %llu",
  			(unsigned long long)atomic64_read(&ic->number_of_mismatches),
  			(unsigned long long)ic->provided_data_sectors);
  		if (ic->sb->flags & cpu_to_le32(SB_FLAG_RECALCULATING))
  			DMEMIT(" %llu", (unsigned long long)le64_to_cpu(ic->sb->recalc_sector));
  		else
  			DMEMIT(" -");
  		break;
  
  	case STATUSTYPE_TABLE: {
  		__u64 watermark_percentage = (__u64)(ic->journal_entries - ic->free_sectors_threshold) * 100;
  		watermark_percentage += ic->journal_entries / 2;
  		do_div(watermark_percentage, ic->journal_entries);
  		arg_count = 3;
  		arg_count += !!ic->meta_dev;
  		arg_count += ic->sectors_per_block != 1;
  		arg_count += !!(ic->sb->flags & cpu_to_le32(SB_FLAG_RECALCULATING));
  		arg_count += ic->mode == 'J';
  		arg_count += ic->mode == 'J';
  		arg_count += ic->mode == 'B';
  		arg_count += ic->mode == 'B';
  		arg_count += !!ic->internal_hash_alg.alg_string;
  		arg_count += !!ic->journal_crypt_alg.alg_string;
  		arg_count += !!ic->journal_mac_alg.alg_string;
  		DMEMIT("%s %llu %u %c %u", ic->dev->name, (unsigned long long)ic->start,
  		       ic->tag_size, ic->mode, arg_count);
  		if (ic->meta_dev)
  			DMEMIT(" meta_device:%s", ic->meta_dev->name);
  		if (ic->sectors_per_block != 1)
  			DMEMIT(" block_size:%u", ic->sectors_per_block << SECTOR_SHIFT);
  		if (ic->recalculate_flag)
  			DMEMIT(" recalculate");
  		DMEMIT(" journal_sectors:%u", ic->initial_sectors - SB_SECTORS);
  		DMEMIT(" interleave_sectors:%u", 1U << ic->sb->log2_interleave_sectors);
  		DMEMIT(" buffer_sectors:%u", 1U << ic->log2_buffer_sectors);
  		if (ic->mode == 'J') {
  			DMEMIT(" journal_watermark:%u", (unsigned)watermark_percentage);
  			DMEMIT(" commit_time:%u", ic->autocommit_msec);
  		}
  		if (ic->mode == 'B') {
  			DMEMIT(" sectors_per_bit:%llu", (unsigned long long)ic->sectors_per_block << ic->log2_blocks_per_bitmap_bit);
  			DMEMIT(" bitmap_flush_interval:%u", jiffies_to_msecs(ic->bitmap_flush_interval));
  		}
  
  #define EMIT_ALG(a, n)							\
  		do {							\
  			if (ic->a.alg_string) {				\
  				DMEMIT(" %s:%s", n, ic->a.alg_string);	\
  				if (ic->a.key_string)			\
  					DMEMIT(":%s", ic->a.key_string);\
  			}						\
  		} while (0)
  		EMIT_ALG(internal_hash_alg, "internal_hash");
  		EMIT_ALG(journal_crypt_alg, "journal_crypt");
  		EMIT_ALG(journal_mac_alg, "journal_mac");
  		break;
  	}
  	}
  }
  
  static int dm_integrity_iterate_devices(struct dm_target *ti,
  					iterate_devices_callout_fn fn, void *data)
  {
  	struct dm_integrity_c *ic = ti->private;
  
  	if (!ic->meta_dev)
  		return fn(ti, ic->dev, ic->start + ic->initial_sectors + ic->metadata_run, ti->len, data);
  	else
  		return fn(ti, ic->dev, 0, ti->len, data);
  }
  
  static void dm_integrity_io_hints(struct dm_target *ti, struct queue_limits *limits)
  {
  	struct dm_integrity_c *ic = ti->private;
  
  	if (ic->sectors_per_block > 1) {
  		limits->logical_block_size = ic->sectors_per_block << SECTOR_SHIFT;
  		limits->physical_block_size = ic->sectors_per_block << SECTOR_SHIFT;
  		blk_limits_io_min(limits, ic->sectors_per_block << SECTOR_SHIFT);
  	}
  }
  
  static void calculate_journal_section_size(struct dm_integrity_c *ic)
  {
  	unsigned sector_space = JOURNAL_SECTOR_DATA;
  
  	ic->journal_sections = le32_to_cpu(ic->sb->journal_sections);
  	ic->journal_entry_size = roundup(offsetof(struct journal_entry, last_bytes[ic->sectors_per_block]) + ic->tag_size,
  					 JOURNAL_ENTRY_ROUNDUP);
  
  	if (ic->sb->flags & cpu_to_le32(SB_FLAG_HAVE_JOURNAL_MAC))
  		sector_space -= JOURNAL_MAC_PER_SECTOR;
  	ic->journal_entries_per_sector = sector_space / ic->journal_entry_size;
  	ic->journal_section_entries = ic->journal_entries_per_sector * JOURNAL_BLOCK_SECTORS;
  	ic->journal_section_sectors = (ic->journal_section_entries << ic->sb->log2_sectors_per_block) + JOURNAL_BLOCK_SECTORS;
  	ic->journal_entries = ic->journal_section_entries * ic->journal_sections;
  }
  
  static int calculate_device_limits(struct dm_integrity_c *ic)
  {
  	__u64 initial_sectors;
  
  	calculate_journal_section_size(ic);
  	initial_sectors = SB_SECTORS + (__u64)ic->journal_section_sectors * ic->journal_sections;
  	if (initial_sectors + METADATA_PADDING_SECTORS >= ic->meta_device_sectors || initial_sectors > UINT_MAX)
  		return -EINVAL;
  	ic->initial_sectors = initial_sectors;
  
  	if (!ic->meta_dev) {
  		sector_t last_sector, last_area, last_offset;
  
  		ic->metadata_run = roundup((__u64)ic->tag_size << (ic->sb->log2_interleave_sectors - ic->sb->log2_sectors_per_block),
  					   (__u64)(1 << SECTOR_SHIFT << METADATA_PADDING_SECTORS)) >> SECTOR_SHIFT;
  		if (!(ic->metadata_run & (ic->metadata_run - 1)))
  			ic->log2_metadata_run = __ffs(ic->metadata_run);
  		else
  			ic->log2_metadata_run = -1;
  
  		get_area_and_offset(ic, ic->provided_data_sectors - 1, &last_area, &last_offset);
  		last_sector = get_data_sector(ic, last_area, last_offset);
  		if (last_sector < ic->start || last_sector >= ic->meta_device_sectors)
  			return -EINVAL;
  	} else {
  		__u64 meta_size = (ic->provided_data_sectors >> ic->sb->log2_sectors_per_block) * ic->tag_size;
  		meta_size = (meta_size + ((1U << (ic->log2_buffer_sectors + SECTOR_SHIFT)) - 1))
  				>> (ic->log2_buffer_sectors + SECTOR_SHIFT);
  		meta_size <<= ic->log2_buffer_sectors;
  		if (ic->initial_sectors + meta_size < ic->initial_sectors ||
  		    ic->initial_sectors + meta_size > ic->meta_device_sectors)
  			return -EINVAL;
  		ic->metadata_run = 1;
  		ic->log2_metadata_run = 0;
  	}
  
  	return 0;
  }
  
  static int initialize_superblock(struct dm_integrity_c *ic, unsigned journal_sectors, unsigned interleave_sectors)
  {
  	unsigned journal_sections;
  	int test_bit;
  
  	memset(ic->sb, 0, SB_SECTORS << SECTOR_SHIFT);
  	memcpy(ic->sb->magic, SB_MAGIC, 8);
  	ic->sb->integrity_tag_size = cpu_to_le16(ic->tag_size);
  	ic->sb->log2_sectors_per_block = __ffs(ic->sectors_per_block);
  	if (ic->journal_mac_alg.alg_string)
  		ic->sb->flags |= cpu_to_le32(SB_FLAG_HAVE_JOURNAL_MAC);
  
  	calculate_journal_section_size(ic);
  	journal_sections = journal_sectors / ic->journal_section_sectors;
  	if (!journal_sections)
  		journal_sections = 1;
  
  	if (!ic->meta_dev) {
  		ic->sb->journal_sections = cpu_to_le32(journal_sections);
  		if (!interleave_sectors)
  			interleave_sectors = DEFAULT_INTERLEAVE_SECTORS;
  		ic->sb->log2_interleave_sectors = __fls(interleave_sectors);
  		ic->sb->log2_interleave_sectors = max((__u8)MIN_LOG2_INTERLEAVE_SECTORS, ic->sb->log2_interleave_sectors);
  		ic->sb->log2_interleave_sectors = min((__u8)MAX_LOG2_INTERLEAVE_SECTORS, ic->sb->log2_interleave_sectors);
  
  		ic->provided_data_sectors = 0;
  		for (test_bit = fls64(ic->meta_device_sectors) - 1; test_bit >= 3; test_bit--) {
  			__u64 prev_data_sectors = ic->provided_data_sectors;
  
  			ic->provided_data_sectors |= (sector_t)1 << test_bit;
  			if (calculate_device_limits(ic))
  				ic->provided_data_sectors = prev_data_sectors;
  		}
  		if (!ic->provided_data_sectors)
  			return -EINVAL;
  	} else {
  		ic->sb->log2_interleave_sectors = 0;
  		ic->provided_data_sectors = ic->data_device_sectors;
  		ic->provided_data_sectors &= ~(sector_t)(ic->sectors_per_block - 1);
  
  try_smaller_buffer:
  		ic->sb->journal_sections = cpu_to_le32(0);
  		for (test_bit = fls(journal_sections) - 1; test_bit >= 0; test_bit--) {
  			__u32 prev_journal_sections = le32_to_cpu(ic->sb->journal_sections);
  			__u32 test_journal_sections = prev_journal_sections | (1U << test_bit);
  			if (test_journal_sections > journal_sections)
  				continue;
  			ic->sb->journal_sections = cpu_to_le32(test_journal_sections);
  			if (calculate_device_limits(ic))
  				ic->sb->journal_sections = cpu_to_le32(prev_journal_sections);
  
  		}
  		if (!le32_to_cpu(ic->sb->journal_sections)) {
  			if (ic->log2_buffer_sectors > 3) {
  				ic->log2_buffer_sectors--;
  				goto try_smaller_buffer;
  			}
  			return -EINVAL;
  		}
  	}
  
  	ic->sb->provided_data_sectors = cpu_to_le64(ic->provided_data_sectors);
  
  	sb_set_version(ic);
  
  	return 0;
  }
  
  static void dm_integrity_set(struct dm_target *ti, struct dm_integrity_c *ic)
  {
  	struct gendisk *disk = dm_disk(dm_table_get_md(ti->table));
  	struct blk_integrity bi;
  
  	memset(&bi, 0, sizeof(bi));
  	bi.profile = &dm_integrity_profile;
  	bi.tuple_size = ic->tag_size;
  	bi.tag_size = bi.tuple_size;
  	bi.interval_exp = ic->sb->log2_sectors_per_block + SECTOR_SHIFT;
  
  	blk_integrity_register(disk, &bi);
  	blk_queue_max_integrity_segments(disk->queue, UINT_MAX);
  }
  
  static void dm_integrity_free_page_list(struct page_list *pl)
  {
  	unsigned i;
  
  	if (!pl)
  		return;
  	for (i = 0; pl[i].page; i++)
  		__free_page(pl[i].page);
  	kvfree(pl);
  }
  
  static struct page_list *dm_integrity_alloc_page_list(unsigned n_pages)
  {
  	struct page_list *pl;
  	unsigned i;
  
  	pl = kvmalloc_array(n_pages + 1, sizeof(struct page_list), GFP_KERNEL | __GFP_ZERO);
  	if (!pl)
  		return NULL;
  
  	for (i = 0; i < n_pages; i++) {
  		pl[i].page = alloc_page(GFP_KERNEL);
  		if (!pl[i].page) {
  			dm_integrity_free_page_list(pl);
  			return NULL;
  		}
  		if (i)
  			pl[i - 1].next = &pl[i];
  	}
  	pl[i].page = NULL;
  	pl[i].next = NULL;
  
  	return pl;
  }
  
  static void dm_integrity_free_journal_scatterlist(struct dm_integrity_c *ic, struct scatterlist **sl)
  {
  	unsigned i;
  	for (i = 0; i < ic->journal_sections; i++)
  		kvfree(sl[i]);
  	kvfree(sl);
  }
  
  static struct scatterlist **dm_integrity_alloc_journal_scatterlist(struct dm_integrity_c *ic,
  								   struct page_list *pl)
  {
  	struct scatterlist **sl;
  	unsigned i;
  
  	sl = kvmalloc_array(ic->journal_sections,
  			    sizeof(struct scatterlist *),
  			    GFP_KERNEL | __GFP_ZERO);
  	if (!sl)
  		return NULL;
  
  	for (i = 0; i < ic->journal_sections; i++) {
  		struct scatterlist *s;
  		unsigned start_index, start_offset;
  		unsigned end_index, end_offset;
  		unsigned n_pages;
  		unsigned idx;
  
  		page_list_location(ic, i, 0, &start_index, &start_offset);
  		page_list_location(ic, i, ic->journal_section_sectors - 1,
  				   &end_index, &end_offset);
  
  		n_pages = (end_index - start_index + 1);
  
  		s = kvmalloc_array(n_pages, sizeof(struct scatterlist),
  				   GFP_KERNEL);
  		if (!s) {
  			dm_integrity_free_journal_scatterlist(ic, sl);
  			return NULL;
  		}
  
  		sg_init_table(s, n_pages);
  		for (idx = start_index; idx <= end_index; idx++) {
  			char *va = lowmem_page_address(pl[idx].page);
  			unsigned start = 0, end = PAGE_SIZE;
  			if (idx == start_index)
  				start = start_offset;
  			if (idx == end_index)
  				end = end_offset + (1 << SECTOR_SHIFT);
  			sg_set_buf(&s[idx - start_index], va + start, end - start);
  		}
  
  		sl[i] = s;
  	}
  
  	return sl;
  }
  
  static void free_alg(struct alg_spec *a)
  {
  	kzfree(a->alg_string);
  	kzfree(a->key);
  	memset(a, 0, sizeof *a);
  }
  
  static int get_alg_and_key(const char *arg, struct alg_spec *a, char **error, char *error_inval)
  {
  	char *k;
  
  	free_alg(a);
  
  	a->alg_string = kstrdup(strchr(arg, ':') + 1, GFP_KERNEL);
  	if (!a->alg_string)
  		goto nomem;
  
  	k = strchr(a->alg_string, ':');
  	if (k) {
  		*k = 0;
  		a->key_string = k + 1;
  		if (strlen(a->key_string) & 1)
  			goto inval;
  
  		a->key_size = strlen(a->key_string) / 2;
  		a->key = kmalloc(a->key_size, GFP_KERNEL);
  		if (!a->key)
  			goto nomem;
  		if (hex2bin(a->key, a->key_string, a->key_size))
  			goto inval;
  	}
  
  	return 0;
  inval:
  	*error = error_inval;
  	return -EINVAL;
  nomem:
  	*error = "Out of memory for an argument";
  	return -ENOMEM;
  }
  
  static int get_mac(struct crypto_shash **hash, struct alg_spec *a, char **error,
  		   char *error_alg, char *error_key)
  {
  	int r;
  
  	if (a->alg_string) {
  		*hash = crypto_alloc_shash(a->alg_string, 0, 0);
  		if (IS_ERR(*hash)) {
  			*error = error_alg;
  			r = PTR_ERR(*hash);
  			*hash = NULL;
  			return r;
  		}
  
  		if (a->key) {
  			r = crypto_shash_setkey(*hash, a->key, a->key_size);
  			if (r) {
  				*error = error_key;
  				return r;
  			}
  		} else if (crypto_shash_get_flags(*hash) & CRYPTO_TFM_NEED_KEY) {
  			*error = error_key;
  			return -ENOKEY;
  		}
  	}
  
  	return 0;
  }
  
  static int create_journal(struct dm_integrity_c *ic, char **error)
  {
  	int r = 0;
  	unsigned i;
  	__u64 journal_pages, journal_desc_size, journal_tree_size;
  	unsigned char *crypt_data = NULL, *crypt_iv = NULL;
  	struct skcipher_request *req = NULL;
  
  	ic->commit_ids[0] = cpu_to_le64(0x1111111111111111ULL);
  	ic->commit_ids[1] = cpu_to_le64(0x2222222222222222ULL);
  	ic->commit_ids[2] = cpu_to_le64(0x3333333333333333ULL);
  	ic->commit_ids[3] = cpu_to_le64(0x4444444444444444ULL);
  
  	journal_pages = roundup((__u64)ic->journal_sections * ic->journal_section_sectors,
  				PAGE_SIZE >> SECTOR_SHIFT) >> (PAGE_SHIFT - SECTOR_SHIFT);
  	journal_desc_size = journal_pages * sizeof(struct page_list);
  	if (journal_pages >= totalram_pages() - totalhigh_pages() || journal_desc_size > ULONG_MAX) {
  		*error = "Journal doesn't fit into memory";
  		r = -ENOMEM;
  		goto bad;
  	}
  	ic->journal_pages = journal_pages;
  
  	ic->journal = dm_integrity_alloc_page_list(ic->journal_pages);
  	if (!ic->journal) {
  		*error = "Could not allocate memory for journal";
  		r = -ENOMEM;
  		goto bad;
  	}
  	if (ic->journal_crypt_alg.alg_string) {
  		unsigned ivsize, blocksize;
  		struct journal_completion comp;
  
  		comp.ic = ic;
  		ic->journal_crypt = crypto_alloc_skcipher(ic->journal_crypt_alg.alg_string, 0, 0);
  		if (IS_ERR(ic->journal_crypt)) {
  			*error = "Invalid journal cipher";
  			r = PTR_ERR(ic->journal_crypt);
  			ic->journal_crypt = NULL;
  			goto bad;
  		}
  		ivsize = crypto_skcipher_ivsize(ic->journal_crypt);
  		blocksize = crypto_skcipher_blocksize(ic->journal_crypt);
  
  		if (ic->journal_crypt_alg.key) {
  			r = crypto_skcipher_setkey(ic->journal_crypt, ic->journal_crypt_alg.key,
  						   ic->journal_crypt_alg.key_size);
  			if (r) {
  				*error = "Error setting encryption key";
  				goto bad;
  			}
  		}
  		DEBUG_print("cipher %s, block size %u iv size %u\n",
  			    ic->journal_crypt_alg.alg_string, blocksize, ivsize);
  
  		ic->journal_io = dm_integrity_alloc_page_list(ic->journal_pages);
  		if (!ic->journal_io) {
  			*error = "Could not allocate memory for journal io";
  			r = -ENOMEM;
  			goto bad;
  		}
  
  		if (blocksize == 1) {
  			struct scatterlist *sg;
  
  			req = skcipher_request_alloc(ic->journal_crypt, GFP_KERNEL);
  			if (!req) {
  				*error = "Could not allocate crypt request";
  				r = -ENOMEM;
  				goto bad;
  			}
  
  			crypt_iv = kmalloc(ivsize, GFP_KERNEL);
  			if (!crypt_iv) {
  				*error = "Could not allocate iv";
  				r = -ENOMEM;
  				goto bad;
  			}
  
  			ic->journal_xor = dm_integrity_alloc_page_list(ic->journal_pages);
  			if (!ic->journal_xor) {
  				*error = "Could not allocate memory for journal xor";
  				r = -ENOMEM;
  				goto bad;
  			}
  
  			sg = kvmalloc_array(ic->journal_pages + 1,
  					    sizeof(struct scatterlist),
  					    GFP_KERNEL);
  			if (!sg) {
  				*error = "Unable to allocate sg list";
  				r = -ENOMEM;
  				goto bad;
  			}
  			sg_init_table(sg, ic->journal_pages + 1);
  			for (i = 0; i < ic->journal_pages; i++) {
  				char *va = lowmem_page_address(ic->journal_xor[i].page);
  				clear_page(va);
  				sg_set_buf(&sg[i], va, PAGE_SIZE);
  			}
  			sg_set_buf(&sg[i], &ic->commit_ids, sizeof ic->commit_ids);
  			memset(crypt_iv, 0x00, ivsize);
  
  			skcipher_request_set_crypt(req, sg, sg,
  						   PAGE_SIZE * ic->journal_pages + sizeof ic->commit_ids, crypt_iv);
  			init_completion(&comp.comp);
  			comp.in_flight = (atomic_t)ATOMIC_INIT(1);
  			if (do_crypt(true, req, &comp))
  				wait_for_completion(&comp.comp);
  			kvfree(sg);
  			r = dm_integrity_failed(ic);
  			if (r) {
  				*error = "Unable to encrypt journal";
  				goto bad;
  			}
  			DEBUG_bytes(lowmem_page_address(ic->journal_xor[0].page), 64, "xor data");
  
  			crypto_free_skcipher(ic->journal_crypt);
  			ic->journal_crypt = NULL;
  		} else {
  			unsigned crypt_len = roundup(ivsize, blocksize);
  
  			req = skcipher_request_alloc(ic->journal_crypt, GFP_KERNEL);
  			if (!req) {
  				*error = "Could not allocate crypt request";
  				r = -ENOMEM;
  				goto bad;
  			}
  
  			crypt_iv = kmalloc(ivsize, GFP_KERNEL);
  			if (!crypt_iv) {
  				*error = "Could not allocate iv";
  				r = -ENOMEM;
  				goto bad;
  			}
  
  			crypt_data = kmalloc(crypt_len, GFP_KERNEL);
  			if (!crypt_data) {
  				*error = "Unable to allocate crypt data";
  				r = -ENOMEM;
  				goto bad;
  			}
  
  			ic->journal_scatterlist = dm_integrity_alloc_journal_scatterlist(ic, ic->journal);
  			if (!ic->journal_scatterlist) {
  				*error = "Unable to allocate sg list";
  				r = -ENOMEM;
  				goto bad;
  			}
  			ic->journal_io_scatterlist = dm_integrity_alloc_journal_scatterlist(ic, ic->journal_io);
  			if (!ic->journal_io_scatterlist) {
  				*error = "Unable to allocate sg list";
  				r = -ENOMEM;
  				goto bad;
  			}
  			ic->sk_requests = kvmalloc_array(ic->journal_sections,
  							 sizeof(struct skcipher_request *),
  							 GFP_KERNEL | __GFP_ZERO);
  			if (!ic->sk_requests) {
  				*error = "Unable to allocate sk requests";
  				r = -ENOMEM;
  				goto bad;
  			}
  			for (i = 0; i < ic->journal_sections; i++) {
  				struct scatterlist sg;
  				struct skcipher_request *section_req;
  				__u32 section_le = cpu_to_le32(i);
  
  				memset(crypt_iv, 0x00, ivsize);
  				memset(crypt_data, 0x00, crypt_len);
  				memcpy(crypt_data, &section_le, min((size_t)crypt_len, sizeof(section_le)));
  
  				sg_init_one(&sg, crypt_data, crypt_len);
  				skcipher_request_set_crypt(req, &sg, &sg, crypt_len, crypt_iv);
  				init_completion(&comp.comp);
  				comp.in_flight = (atomic_t)ATOMIC_INIT(1);
  				if (do_crypt(true, req, &comp))
  					wait_for_completion(&comp.comp);
  
  				r = dm_integrity_failed(ic);
  				if (r) {
  					*error = "Unable to generate iv";
  					goto bad;
  				}
  
  				section_req = skcipher_request_alloc(ic->journal_crypt, GFP_KERNEL);
  				if (!section_req) {
  					*error = "Unable to allocate crypt request";
  					r = -ENOMEM;
  					goto bad;
  				}
  				section_req->iv = kmalloc_array(ivsize, 2,
  								GFP_KERNEL);
  				if (!section_req->iv) {
  					skcipher_request_free(section_req);
  					*error = "Unable to allocate iv";
  					r = -ENOMEM;
  					goto bad;
  				}
  				memcpy(section_req->iv + ivsize, crypt_data, ivsize);
  				section_req->cryptlen = (size_t)ic->journal_section_sectors << SECTOR_SHIFT;
  				ic->sk_requests[i] = section_req;
  				DEBUG_bytes(crypt_data, ivsize, "iv(%u)", i);
  			}
  		}
  	}
  
  	for (i = 0; i < N_COMMIT_IDS; i++) {
  		unsigned j;
  retest_commit_id:
  		for (j = 0; j < i; j++) {
  			if (ic->commit_ids[j] == ic->commit_ids[i]) {
  				ic->commit_ids[i] = cpu_to_le64(le64_to_cpu(ic->commit_ids[i]) + 1);
  				goto retest_commit_id;
  			}
  		}
  		DEBUG_print("commit id %u: %016llx\n", i, ic->commit_ids[i]);
  	}
  
  	journal_tree_size = (__u64)ic->journal_entries * sizeof(struct journal_node);
  	if (journal_tree_size > ULONG_MAX) {
  		*error = "Journal doesn't fit into memory";
  		r = -ENOMEM;
  		goto bad;
  	}
  	ic->journal_tree = kvmalloc(journal_tree_size, GFP_KERNEL);
  	if (!ic->journal_tree) {
  		*error = "Could not allocate memory for journal tree";
  		r = -ENOMEM;
  	}
  bad:
  	kfree(crypt_data);
  	kfree(crypt_iv);
  	skcipher_request_free(req);
  
  	return r;
  }
  
  /*
   * Construct a integrity mapping
   *
   * Arguments:
   *	device
   *	offset from the start of the device
   *	tag size
   *	D - direct writes, J - journal writes, B - bitmap mode, R - recovery mode
   *	number of optional arguments
   *	optional arguments:
   *		journal_sectors
   *		interleave_sectors
   *		buffer_sectors
   *		journal_watermark
   *		commit_time
   *		meta_device
   *		block_size
   *		sectors_per_bit
   *		bitmap_flush_interval
   *		internal_hash
   *		journal_crypt
   *		journal_mac
   *		recalculate
   */
  static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv)
  {
  	struct dm_integrity_c *ic;
  	char dummy;
  	int r;
  	unsigned extra_args;
  	struct dm_arg_set as;
  	static const struct dm_arg _args[] = {
  		{0, 9, "Invalid number of feature args"},
  	};
  	unsigned journal_sectors, interleave_sectors, buffer_sectors, journal_watermark, sync_msec;
  	bool should_write_sb;
  	__u64 threshold;
  	unsigned long long start;
  	__s8 log2_sectors_per_bitmap_bit = -1;
  	__s8 log2_blocks_per_bitmap_bit;
  	__u64 bits_in_journal;
  	__u64 n_bitmap_bits;
  
  #define DIRECT_ARGUMENTS	4
  
  	if (argc <= DIRECT_ARGUMENTS) {
  		ti->error = "Invalid argument count";
  		return -EINVAL;
  	}
  
  	ic = kzalloc(sizeof(struct dm_integrity_c), GFP_KERNEL);
  	if (!ic) {
  		ti->error = "Cannot allocate integrity context";
  		return -ENOMEM;
  	}
  	ti->private = ic;
  	ti->per_io_data_size = sizeof(struct dm_integrity_io);
  
  	ic->in_progress = RB_ROOT;
  	INIT_LIST_HEAD(&ic->wait_list);
  	init_waitqueue_head(&ic->endio_wait);
  	bio_list_init(&ic->flush_bio_list);
  	init_waitqueue_head(&ic->copy_to_journal_wait);
  	init_completion(&ic->crypto_backoff);
  	atomic64_set(&ic->number_of_mismatches, 0);
  	ic->bitmap_flush_interval = BITMAP_FLUSH_INTERVAL;
  
  	r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &ic->dev);
  	if (r) {
  		ti->error = "Device lookup failed";
  		goto bad;
  	}
  
  	if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1 || start != (sector_t)start) {
  		ti->error = "Invalid starting offset";
  		r = -EINVAL;
  		goto bad;
  	}
  	ic->start = start;
  
  	if (strcmp(argv[2], "-")) {
  		if (sscanf(argv[2], "%u%c", &ic->tag_size, &dummy) != 1 || !ic->tag_size) {
  			ti->error = "Invalid tag size";
  			r = -EINVAL;
  			goto bad;
  		}
  	}
  
  	if (!strcmp(argv[3], "J") || !strcmp(argv[3], "B") ||
  	    !strcmp(argv[3], "D") || !strcmp(argv[3], "R")) {
  		ic->mode = argv[3][0];
  	} else {
  		ti->error = "Invalid mode (expecting J, B, D, R)";
  		r = -EINVAL;
  		goto bad;
  	}
  
  	journal_sectors = 0;
  	interleave_sectors = DEFAULT_INTERLEAVE_SECTORS;
  	buffer_sectors = DEFAULT_BUFFER_SECTORS;
  	journal_watermark = DEFAULT_JOURNAL_WATERMARK;
  	sync_msec = DEFAULT_SYNC_MSEC;
  	ic->sectors_per_block = 1;
  
  	as.argc = argc - DIRECT_ARGUMENTS;
  	as.argv = argv + DIRECT_ARGUMENTS;
  	r = dm_read_arg_group(_args, &as, &extra_args, &ti->error);
  	if (r)
  		goto bad;
  
  	while (extra_args--) {
  		const char *opt_string;
  		unsigned val;
  		unsigned long long llval;
  		opt_string = dm_shift_arg(&as);
  		if (!opt_string) {
  			r = -EINVAL;
  			ti->error = "Not enough feature arguments";
  			goto bad;
  		}
  		if (sscanf(opt_string, "journal_sectors:%u%c", &val, &dummy) == 1)
  			journal_sectors = val ? val : 1;
  		else if (sscanf(opt_string, "interleave_sectors:%u%c", &val, &dummy) == 1)
  			interleave_sectors = val;
  		else if (sscanf(opt_string, "buffer_sectors:%u%c", &val, &dummy) == 1)
  			buffer_sectors = val;
  		else if (sscanf(opt_string, "journal_watermark:%u%c", &val, &dummy) == 1 && val <= 100)
  			journal_watermark = val;
  		else if (sscanf(opt_string, "commit_time:%u%c", &val, &dummy) == 1)
  			sync_msec = val;
  		else if (!strncmp(opt_string, "meta_device:", strlen("meta_device:"))) {
  			if (ic->meta_dev) {
  				dm_put_device(ti, ic->meta_dev);
  				ic->meta_dev = NULL;
  			}
  			r = dm_get_device(ti, strchr(opt_string, ':') + 1,
  					  dm_table_get_mode(ti->table), &ic->meta_dev);
  			if (r) {
  				ti->error = "Device lookup failed";
  				goto bad;
  			}
  		} else if (sscanf(opt_string, "block_size:%u%c", &val, &dummy) == 1) {
  			if (val < 1 << SECTOR_SHIFT ||
  			    val > MAX_SECTORS_PER_BLOCK << SECTOR_SHIFT ||
  			    (val & (val -1))) {
  				r = -EINVAL;
  				ti->error = "Invalid block_size argument";
  				goto bad;
  			}
  			ic->sectors_per_block = val >> SECTOR_SHIFT;
  		} else if (sscanf(opt_string, "sectors_per_bit:%llu%c", &llval, &dummy) == 1) {
  			log2_sectors_per_bitmap_bit = !llval ? 0 : __ilog2_u64(llval);
  		} else if (sscanf(opt_string, "bitmap_flush_interval:%u%c", &val, &dummy) == 1) {
  			if (val >= (uint64_t)UINT_MAX * 1000 / HZ) {
  				r = -EINVAL;
  				ti->error = "Invalid bitmap_flush_interval argument";
  			}
  			ic->bitmap_flush_interval = msecs_to_jiffies(val);
  		} else if (!strncmp(opt_string, "internal_hash:", strlen("internal_hash:"))) {
  			r = get_alg_and_key(opt_string, &ic->internal_hash_alg, &ti->error,
  					    "Invalid internal_hash argument");
  			if (r)
  				goto bad;
  		} else if (!strncmp(opt_string, "journal_crypt:", strlen("journal_crypt:"))) {
  			r = get_alg_and_key(opt_string, &ic->journal_crypt_alg, &ti->error,
  					    "Invalid journal_crypt argument");
  			if (r)
  				goto bad;
  		} else if (!strncmp(opt_string, "journal_mac:", strlen("journal_mac:"))) {
  			r = get_alg_and_key(opt_string, &ic->journal_mac_alg,  &ti->error,
  					    "Invalid journal_mac argument");
  			if (r)
  				goto bad;
  		} else if (!strcmp(opt_string, "recalculate")) {
  			ic->recalculate_flag = true;
  		} else {
  			r = -EINVAL;
  			ti->error = "Invalid argument";
  			goto bad;
  		}
  	}
  
  	ic->data_device_sectors = i_size_read(ic->dev->bdev->bd_inode) >> SECTOR_SHIFT;
  	if (!ic->meta_dev)
  		ic->meta_device_sectors = ic->data_device_sectors;
  	else
  		ic->meta_device_sectors = i_size_read(ic->meta_dev->bdev->bd_inode) >> SECTOR_SHIFT;
  
  	if (!journal_sectors) {
  		journal_sectors = min((sector_t)DEFAULT_MAX_JOURNAL_SECTORS,
  				      ic->data_device_sectors >> DEFAULT_JOURNAL_SIZE_FACTOR);
  	}
  
  	if (!buffer_sectors)
  		buffer_sectors = 1;
  	ic->log2_buffer_sectors = min((int)__fls(buffer_sectors), 31 - SECTOR_SHIFT);
  
  	r = get_mac(&ic->internal_hash, &ic->internal_hash_alg, &ti->error,
  		    "Invalid internal hash", "Error setting internal hash key");
  	if (r)
  		goto bad;
  
  	r = get_mac(&ic->journal_mac, &ic->journal_mac_alg, &ti->error,
  		    "Invalid journal mac", "Error setting journal mac key");
  	if (r)
  		goto bad;
  
  	if (!ic->tag_size) {
  		if (!ic->internal_hash) {
  			ti->error = "Unknown tag size";
  			r = -EINVAL;
  			goto bad;
  		}
  		ic->tag_size = crypto_shash_digestsize(ic->internal_hash);
  	}
  	if (ic->tag_size > MAX_TAG_SIZE) {
  		ti->error = "Too big tag size";
  		r = -EINVAL;
  		goto bad;
  	}
  	if (!(ic->tag_size & (ic->tag_size - 1)))
  		ic->log2_tag_size = __ffs(ic->tag_size);
  	else
  		ic->log2_tag_size = -1;
  
  	if (ic->mode == 'B' && !ic->internal_hash) {
  		r = -EINVAL;
  		ti->error = "Bitmap mode can be only used with internal hash";
  		goto bad;
  	}
  
  	ic->autocommit_jiffies = msecs_to_jiffies(sync_msec);
  	ic->autocommit_msec = sync_msec;
  	timer_setup(&ic->autocommit_timer, autocommit_fn, 0);
  
  	ic->io = dm_io_client_create();
  	if (IS_ERR(ic->io)) {
  		r = PTR_ERR(ic->io);
  		ic->io = NULL;
  		ti->error = "Cannot allocate dm io";
  		goto bad;
  	}
  
  	r = mempool_init_slab_pool(&ic->journal_io_mempool, JOURNAL_IO_MEMPOOL, journal_io_cache);
  	if (r) {
  		ti->error = "Cannot allocate mempool";
  		goto bad;
  	}
  
  	ic->metadata_wq = alloc_workqueue("dm-integrity-metadata",
  					  WQ_MEM_RECLAIM, METADATA_WORKQUEUE_MAX_ACTIVE);
  	if (!ic->metadata_wq) {
  		ti->error = "Cannot allocate workqueue";
  		r = -ENOMEM;
  		goto bad;
  	}
  
  	/*
  	 * If this workqueue were percpu, it would cause bio reordering
  	 * and reduced performance.
  	 */
  	ic->wait_wq = alloc_workqueue("dm-integrity-wait", WQ_MEM_RECLAIM | WQ_UNBOUND, 1);
  	if (!ic->wait_wq) {
  		ti->error = "Cannot allocate workqueue";
  		r = -ENOMEM;
  		goto bad;
  	}
  
  	ic->commit_wq = alloc_workqueue("dm-integrity-commit", WQ_MEM_RECLAIM, 1);
  	if (!ic->commit_wq) {
  		ti->error = "Cannot allocate workqueue";
  		r = -ENOMEM;
  		goto bad;
  	}
  	INIT_WORK(&ic->commit_work, integrity_commit);
  
  	if (ic->mode == 'J' || ic->mode == 'B') {
  		ic->writer_wq = alloc_workqueue("dm-integrity-writer", WQ_MEM_RECLAIM, 1);
  		if (!ic->writer_wq) {
  			ti->error = "Cannot allocate workqueue";
  			r = -ENOMEM;
  			goto bad;
  		}
  		INIT_WORK(&ic->writer_work, integrity_writer);
  	}
  
  	ic->sb = alloc_pages_exact(SB_SECTORS << SECTOR_SHIFT, GFP_KERNEL);
  	if (!ic->sb) {
  		r = -ENOMEM;
  		ti->error = "Cannot allocate superblock area";
  		goto bad;
  	}
  
  	r = sync_rw_sb(ic, REQ_OP_READ, 0);
  	if (r) {
  		ti->error = "Error reading superblock";
  		goto bad;
  	}
  	should_write_sb = false;
  	if (memcmp(ic->sb->magic, SB_MAGIC, 8)) {
  		if (ic->mode != 'R') {
  			if (memchr_inv(ic->sb, 0, SB_SECTORS << SECTOR_SHIFT)) {
  				r = -EINVAL;
  				ti->error = "The device is not initialized";
  				goto bad;
  			}
  		}
  
  		r = initialize_superblock(ic, journal_sectors, interleave_sectors);
  		if (r) {
  			ti->error = "Could not initialize superblock";
  			goto bad;
  		}
  		if (ic->mode != 'R')
  			should_write_sb = true;
  	}
  
  	if (!ic->sb->version || ic->sb->version > SB_VERSION_3) {
  		r = -EINVAL;
  		ti->error = "Unknown version";
  		goto bad;
  	}
  	if (le16_to_cpu(ic->sb->integrity_tag_size) != ic->tag_size) {
  		r = -EINVAL;
  		ti->error = "Tag size doesn't match the information in superblock";
  		goto bad;
  	}
  	if (ic->sb->log2_sectors_per_block != __ffs(ic->sectors_per_block)) {
  		r = -EINVAL;
  		ti->error = "Block size doesn't match the information in superblock";
  		goto bad;
  	}
  	if (!le32_to_cpu(ic->sb->journal_sections)) {
  		r = -EINVAL;
  		ti->error = "Corrupted superblock, journal_sections is 0";
  		goto bad;
  	}
  	/* make sure that ti->max_io_len doesn't overflow */
  	if (!ic->meta_dev) {
  		if (ic->sb->log2_interleave_sectors < MIN_LOG2_INTERLEAVE_SECTORS ||
  		    ic->sb->log2_interleave_sectors > MAX_LOG2_INTERLEAVE_SECTORS) {
  			r = -EINVAL;
  			ti->error = "Invalid interleave_sectors in the superblock";
  			goto bad;
  		}
  	} else {
  		if (ic->sb->log2_interleave_sectors) {
  			r = -EINVAL;
  			ti->error = "Invalid interleave_sectors in the superblock";
  			goto bad;
  		}
  	}
  	ic->provided_data_sectors = le64_to_cpu(ic->sb->provided_data_sectors);
  	if (ic->provided_data_sectors != le64_to_cpu(ic->sb->provided_data_sectors)) {
  		/* test for overflow */
  		r = -EINVAL;
  		ti->error = "The superblock has 64-bit device size, but the kernel was compiled with 32-bit sectors";
  		goto bad;
  	}
  	if (!!(ic->sb->flags & cpu_to_le32(SB_FLAG_HAVE_JOURNAL_MAC)) != !!ic->journal_mac_alg.alg_string) {
  		r = -EINVAL;
  		ti->error = "Journal mac mismatch";
  		goto bad;
  	}
  
  try_smaller_buffer:
  	r = calculate_device_limits(ic);
  	if (r) {
  		if (ic->meta_dev) {
  			if (ic->log2_buffer_sectors > 3) {
  				ic->log2_buffer_sectors--;
  				goto try_smaller_buffer;
  			}
  		}
  		ti->error = "The device is too small";
  		goto bad;
  	}
  
  	if (log2_sectors_per_bitmap_bit < 0)
  		log2_sectors_per_bitmap_bit = __fls(DEFAULT_SECTORS_PER_BITMAP_BIT);
  	if (log2_sectors_per_bitmap_bit < ic->sb->log2_sectors_per_block)
  		log2_sectors_per_bitmap_bit = ic->sb->log2_sectors_per_block;
  
  	bits_in_journal = ((__u64)ic->journal_section_sectors * ic->journal_sections) << (SECTOR_SHIFT + 3);
  	if (bits_in_journal > UINT_MAX)
  		bits_in_journal = UINT_MAX;
  	while (bits_in_journal < (ic->provided_data_sectors + ((sector_t)1 << log2_sectors_per_bitmap_bit) - 1) >> log2_sectors_per_bitmap_bit)
  		log2_sectors_per_bitmap_bit++;
  
  	log2_blocks_per_bitmap_bit = log2_sectors_per_bitmap_bit - ic->sb->log2_sectors_per_block;
  	ic->log2_blocks_per_bitmap_bit = log2_blocks_per_bitmap_bit;
  	if (should_write_sb) {
  		ic->sb->log2_blocks_per_bitmap_bit = log2_blocks_per_bitmap_bit;
  	}
  	n_bitmap_bits = ((ic->provided_data_sectors >> ic->sb->log2_sectors_per_block)
  				+ (((sector_t)1 << log2_blocks_per_bitmap_bit) - 1)) >> log2_blocks_per_bitmap_bit;
  	ic->n_bitmap_blocks = DIV_ROUND_UP(n_bitmap_bits, BITMAP_BLOCK_SIZE * 8);
  
  	if (!ic->meta_dev)
  		ic->log2_buffer_sectors = min(ic->log2_buffer_sectors, (__u8)__ffs(ic->metadata_run));
  
  	if (ti->len > ic->provided_data_sectors) {
  		r = -EINVAL;
  		ti->error = "Not enough provided sectors for requested mapping size";
  		goto bad;
  	}
  
  
  	threshold = (__u64)ic->journal_entries * (100 - journal_watermark);
  	threshold += 50;
  	do_div(threshold, 100);
  	ic->free_sectors_threshold = threshold;
  
  	DEBUG_print("initialized:\n");
  	DEBUG_print("	integrity_tag_size %u\n", le16_to_cpu(ic->sb->integrity_tag_size));
  	DEBUG_print("	journal_entry_size %u\n", ic->journal_entry_size);
  	DEBUG_print("	journal_entries_per_sector %u\n", ic->journal_entries_per_sector);
  	DEBUG_print("	journal_section_entries %u\n", ic->journal_section_entries);
  	DEBUG_print("	journal_section_sectors %u\n", ic->journal_section_sectors);
  	DEBUG_print("	journal_sections %u\n", (unsigned)le32_to_cpu(ic->sb->journal_sections));
  	DEBUG_print("	journal_entries %u\n", ic->journal_entries);
  	DEBUG_print("	log2_interleave_sectors %d\n", ic->sb->log2_interleave_sectors);
  	DEBUG_print("	data_device_sectors 0x%llx\n", i_size_read(ic->dev->bdev->bd_inode) >> SECTOR_SHIFT);
  	DEBUG_print("	initial_sectors 0x%x\n", ic->initial_sectors);
  	DEBUG_print("	metadata_run 0x%x\n", ic->metadata_run);
  	DEBUG_print("	log2_metadata_run %d\n", ic->log2_metadata_run);
  	DEBUG_print("	provided_data_sectors 0x%llx (%llu)\n", (unsigned long long)ic->provided_data_sectors,
  		    (unsigned long long)ic->provided_data_sectors);
  	DEBUG_print("	log2_buffer_sectors %u\n", ic->log2_buffer_sectors);
  	DEBUG_print("	bits_in_journal %llu\n", (unsigned long long)bits_in_journal);
  
  	if (ic->recalculate_flag && !(ic->sb->flags & cpu_to_le32(SB_FLAG_RECALCULATING))) {
  		ic->sb->flags |= cpu_to_le32(SB_FLAG_RECALCULATING);
  		ic->sb->recalc_sector = cpu_to_le64(0);
  	}
  
  	if (ic->internal_hash) {
  		ic->recalc_wq = alloc_workqueue("dm-integrity-recalc", WQ_MEM_RECLAIM, 1);
  		if (!ic->recalc_wq ) {
  			ti->error = "Cannot allocate workqueue";
  			r = -ENOMEM;
  			goto bad;
  		}
  		INIT_WORK(&ic->recalc_work, integrity_recalc);
  		ic->recalc_buffer = vmalloc(RECALC_SECTORS << SECTOR_SHIFT);
  		if (!ic->recalc_buffer) {
  			ti->error = "Cannot allocate buffer for recalculating";
  			r = -ENOMEM;
  			goto bad;
  		}
  		ic->recalc_tags = kvmalloc_array(RECALC_SECTORS >> ic->sb->log2_sectors_per_block,
  						 ic->tag_size, GFP_KERNEL);
  		if (!ic->recalc_tags) {
  			ti->error = "Cannot allocate tags for recalculating";
  			r = -ENOMEM;
  			goto bad;
  		}
  	}
  
  	ic->bufio = dm_bufio_client_create(ic->meta_dev ? ic->meta_dev->bdev : ic->dev->bdev,
  			1U << (SECTOR_SHIFT + ic->log2_buffer_sectors), 1, 0, NULL, NULL);
  	if (IS_ERR(ic->bufio)) {
  		r = PTR_ERR(ic->bufio);
  		ti->error = "Cannot initialize dm-bufio";
  		ic->bufio = NULL;
  		goto bad;
  	}
  	dm_bufio_set_sector_offset(ic->bufio, ic->start + ic->initial_sectors);
  
  	if (ic->mode != 'R') {
  		r = create_journal(ic, &ti->error);
  		if (r)
  			goto bad;
  
  	}
  
  	if (ic->mode == 'B') {
  		unsigned i;
  		unsigned n_bitmap_pages = DIV_ROUND_UP(ic->n_bitmap_blocks, PAGE_SIZE / BITMAP_BLOCK_SIZE);
  
  		ic->recalc_bitmap = dm_integrity_alloc_page_list(n_bitmap_pages);
  		if (!ic->recalc_bitmap) {
  			r = -ENOMEM;
  			goto bad;
  		}
  		ic->may_write_bitmap = dm_integrity_alloc_page_list(n_bitmap_pages);
  		if (!ic->may_write_bitmap) {
  			r = -ENOMEM;
  			goto bad;
  		}
  		ic->bbs = kvmalloc_array(ic->n_bitmap_blocks, sizeof(struct bitmap_block_status), GFP_KERNEL);
  		if (!ic->bbs) {
  			r = -ENOMEM;
  			goto bad;
  		}
  		INIT_DELAYED_WORK(&ic->bitmap_flush_work, bitmap_flush_work);
  		for (i = 0; i < ic->n_bitmap_blocks; i++) {
  			struct bitmap_block_status *bbs = &ic->bbs[i];
  			unsigned sector, pl_index, pl_offset;
  
  			INIT_WORK(&bbs->work, bitmap_block_work);
  			bbs->ic = ic;
  			bbs->idx = i;
  			bio_list_init(&bbs->bio_queue);
  			spin_lock_init(&bbs->bio_queue_lock);
  
  			sector = i * (BITMAP_BLOCK_SIZE >> SECTOR_SHIFT);
  			pl_index = sector >> (PAGE_SHIFT - SECTOR_SHIFT);
  			pl_offset = (sector << SECTOR_SHIFT) & (PAGE_SIZE - 1);
  
  			bbs->bitmap = lowmem_page_address(ic->journal[pl_index].page) + pl_offset;
  		}
  	}
  
  	if (should_write_sb) {
  		int r;
  
  		init_journal(ic, 0, ic->journal_sections, 0);
  		r = dm_integrity_failed(ic);
  		if (unlikely(r)) {
  			ti->error = "Error initializing journal";
  			goto bad;
  		}
  		r = sync_rw_sb(ic, REQ_OP_WRITE, REQ_FUA);
  		if (r) {
  			ti->error = "Error initializing superblock";
  			goto bad;
  		}
  		ic->just_formatted = true;
  	}
  
  	if (!ic->meta_dev) {
  		r = dm_set_target_max_io_len(ti, 1U << ic->sb->log2_interleave_sectors);
  		if (r)
  			goto bad;
  	}
  	if (ic->mode == 'B') {
  		unsigned max_io_len = ((sector_t)ic->sectors_per_block << ic->log2_blocks_per_bitmap_bit) * (BITMAP_BLOCK_SIZE * 8);
  		if (!max_io_len)
  			max_io_len = 1U << 31;
  		DEBUG_print("max_io_len: old %u, new %u\n", ti->max_io_len, max_io_len);
  		if (!ti->max_io_len || ti->max_io_len > max_io_len) {
  			r = dm_set_target_max_io_len(ti, max_io_len);
  			if (r)
  				goto bad;
  		}
  	}
  
  	if (!ic->internal_hash)
  		dm_integrity_set(ti, ic);
  
  	ti->num_flush_bios = 1;
  	ti->flush_supported = true;
  
  	return 0;
  
  bad:
  	dm_integrity_dtr(ti);
  	return r;
  }
  
  static void dm_integrity_dtr(struct dm_target *ti)
  {
  	struct dm_integrity_c *ic = ti->private;
  
  	BUG_ON(!RB_EMPTY_ROOT(&ic->in_progress));
  	BUG_ON(!list_empty(&ic->wait_list));
  
  	if (ic->metadata_wq)
  		destroy_workqueue(ic->metadata_wq);
  	if (ic->wait_wq)
  		destroy_workqueue(ic->wait_wq);
  	if (ic->commit_wq)
  		destroy_workqueue(ic->commit_wq);
  	if (ic->writer_wq)
  		destroy_workqueue(ic->writer_wq);
  	if (ic->recalc_wq)
  		destroy_workqueue(ic->recalc_wq);
  	vfree(ic->recalc_buffer);
  	kvfree(ic->recalc_tags);
  	kvfree(ic->bbs);
  	if (ic->bufio)
  		dm_bufio_client_destroy(ic->bufio);
  	mempool_exit(&ic->journal_io_mempool);
  	if (ic->io)
  		dm_io_client_destroy(ic->io);
  	if (ic->dev)
  		dm_put_device(ti, ic->dev);
  	if (ic->meta_dev)
  		dm_put_device(ti, ic->meta_dev);
  	dm_integrity_free_page_list(ic->journal);
  	dm_integrity_free_page_list(ic->journal_io);
  	dm_integrity_free_page_list(ic->journal_xor);
  	dm_integrity_free_page_list(ic->recalc_bitmap);
  	dm_integrity_free_page_list(ic->may_write_bitmap);
  	if (ic->journal_scatterlist)
  		dm_integrity_free_journal_scatterlist(ic, ic->journal_scatterlist);
  	if (ic->journal_io_scatterlist)
  		dm_integrity_free_journal_scatterlist(ic, ic->journal_io_scatterlist);
  	if (ic->sk_requests) {
  		unsigned i;
  
  		for (i = 0; i < ic->journal_sections; i++) {
  			struct skcipher_request *req = ic->sk_requests[i];
  			if (req) {
  				kzfree(req->iv);
  				skcipher_request_free(req);
  			}
  		}
  		kvfree(ic->sk_requests);
  	}
  	kvfree(ic->journal_tree);
  	if (ic->sb)
  		free_pages_exact(ic->sb, SB_SECTORS << SECTOR_SHIFT);
  
  	if (ic->internal_hash)
  		crypto_free_shash(ic->internal_hash);
  	free_alg(&ic->internal_hash_alg);
  
  	if (ic->journal_crypt)
  		crypto_free_skcipher(ic->journal_crypt);
  	free_alg(&ic->journal_crypt_alg);
  
  	if (ic->journal_mac)
  		crypto_free_shash(ic->journal_mac);
  	free_alg(&ic->journal_mac_alg);
  
  	kfree(ic);
  }
  
  static struct target_type integrity_target = {
  	.name			= "integrity",
  	.version		= {1, 3, 0},
  	.module			= THIS_MODULE,
  	.features		= DM_TARGET_SINGLETON | DM_TARGET_INTEGRITY,
  	.ctr			= dm_integrity_ctr,
  	.dtr			= dm_integrity_dtr,
  	.map			= dm_integrity_map,
  	.postsuspend		= dm_integrity_postsuspend,
  	.resume			= dm_integrity_resume,
  	.status			= dm_integrity_status,
  	.iterate_devices	= dm_integrity_iterate_devices,
  	.io_hints		= dm_integrity_io_hints,
  };
  
  static int __init dm_integrity_init(void)
  {
  	int r;
  
  	journal_io_cache = kmem_cache_create("integrity_journal_io",
  					     sizeof(struct journal_io), 0, 0, NULL);
  	if (!journal_io_cache) {
  		DMERR("can't allocate journal io cache");
  		return -ENOMEM;
  	}
  
  	r = dm_register_target(&integrity_target);
  
  	if (r < 0)
  		DMERR("register failed %d", r);
  
  	return r;
  }
  
  static void __exit dm_integrity_exit(void)
  {
  	dm_unregister_target(&integrity_target);
  	kmem_cache_destroy(journal_io_cache);
  }
  
  module_init(dm_integrity_init);
  module_exit(dm_integrity_exit);
  
  MODULE_AUTHOR("Milan Broz");
  MODULE_AUTHOR("Mikulas Patocka");
  MODULE_DESCRIPTION(DM_NAME " target for integrity tags extension");
  MODULE_LICENSE("GPL");
  