}
 
 /**
- * calc_crc_cont - check CRC of blocks continuously
- * @sbi: nilfs_sb_info
+ * nilfs_compute_checksum - compute checksum of blocks continuously
+ * @nilfs: nilfs object
  * @bhs: buffer head of start block
  * @sum: place to store result
  * @offset: offset bytes in the first block
  * @start: DBN of start block
  * @nblock: number of blocks to be checked
  */
-static int calc_crc_cont(struct nilfs_sb_info *sbi, struct buffer_head *bhs,
-                        u32 *sum, unsigned long offset, u64 check_bytes,
-                        sector_t start, unsigned long nblock)
+static int nilfs_compute_checksum(struct the_nilfs *nilfs,
+                                 struct buffer_head *bhs, u32 *sum,
+                                 unsigned long offset, u64 check_bytes,
+                                 sector_t start, unsigned long nblock)
 {
-       unsigned long blocksize = sbi->s_super->s_blocksize;
+       unsigned int blocksize = nilfs->ns_blocksize;
        unsigned long size;
        u32 crc;
 
        BUG_ON(offset >= blocksize);
        check_bytes -= offset;
        size = min_t(u64, check_bytes, blocksize - offset);
-       crc = crc32_le(sbi->s_nilfs->ns_crc_seed,
+       crc = crc32_le(nilfs->ns_crc_seed,
                       (unsigned char *)bhs->b_data + offset, size);
        if (--nblock > 0) {
                do {
-                       struct buffer_head *bh
-                               = sb_bread(sbi->s_super, ++start);
+                       struct buffer_head *bh;
+
+                       bh = __bread(nilfs->ns_bdev, ++start, blocksize);
                        if (!bh)
                                return -EIO;
                        check_bytes -= size;
 
 /**
  * nilfs_read_super_root_block - read super root block
- * @sb: super_block
+ * @nilfs: nilfs object
  * @sr_block: disk block number of the super root block
  * @pbh: address of a buffer_head pointer to return super root buffer
  * @check: CRC check flag
  */
-int nilfs_read_super_root_block(struct super_block *sb, sector_t sr_block,
+int nilfs_read_super_root_block(struct the_nilfs *nilfs, sector_t sr_block,
                                struct buffer_head **pbh, int check)
 {
        struct buffer_head *bh_sr;
        int ret;
 
        *pbh = NULL;
-       bh_sr = sb_bread(sb, sr_block);
+       bh_sr = __bread(nilfs->ns_bdev, sr_block, nilfs->ns_blocksize);
        if (unlikely(!bh_sr)) {
                ret = NILFS_SEG_FAIL_IO;
                goto failed;
        if (check) {
                unsigned bytes = le16_to_cpu(sr->sr_bytes);
 
-               if (bytes == 0 || bytes > sb->s_blocksize) {
+               if (bytes == 0 || bytes > nilfs->ns_blocksize) {
                        ret = NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT;
                        goto failed_bh;
                }
-               if (calc_crc_cont(NILFS_SB(sb), bh_sr, &crc,
-                                 sizeof(sr->sr_sum), bytes, sr_block, 1)) {
+               if (nilfs_compute_checksum(
+                           nilfs, bh_sr, &crc, sizeof(sr->sr_sum), bytes,
+                           sr_block, 1)) {
                        ret = NILFS_SEG_FAIL_IO;
                        goto failed_bh;
                }
 
 /**
  * load_segment_summary - read segment summary of the specified partial segment
- * @sbi: nilfs_sb_info
+ * @nilfs: nilfs object
  * @pseg_start: start disk block number of partial segment
  * @seg_seq: sequence number requested
  * @ssi: pointer to nilfs_segsum_info struct to store information
  */
 static int
-load_segment_summary(struct nilfs_sb_info *sbi, sector_t pseg_start,
+load_segment_summary(struct the_nilfs *nilfs, sector_t pseg_start,
                     u64 seg_seq, struct nilfs_segsum_info *ssi)
 {
        struct buffer_head *bh_sum;
        u32 crc;
        int ret = NILFS_SEG_FAIL_IO;
 
-       bh_sum = sb_bread(sbi->s_super, pseg_start);
+       bh_sum = __bread(nilfs->ns_bdev, pseg_start, nilfs->ns_blocksize);
        if (!bh_sum)
                goto out;
 
                ret = NILFS_SEG_FAIL_MAGIC;
                goto failed;
        }
-       store_segsum_info(ssi, sum, sbi->s_super->s_blocksize);
+       store_segsum_info(ssi, sum, nilfs->ns_blocksize);
        if (seg_seq != ssi->seg_seq) {
                ret = NILFS_SEG_FAIL_SEQ;
                goto failed;
        }
 
        nblock = ssi->nblocks;
-       if (unlikely(nblock == 0 ||
-                    nblock > sbi->s_nilfs->ns_blocks_per_segment)) {
+       if (unlikely(nblock == 0 || nblock > nilfs->ns_blocks_per_segment)) {
                /* This limits the number of blocks read in the CRC check */
                ret = NILFS_SEG_FAIL_CONSISTENCY;
                goto failed;
        }
-       if (calc_crc_cont(sbi, bh_sum, &crc, sizeof(sum->ss_datasum),
-                         ((u64)nblock << sbi->s_super->s_blocksize_bits),
-                         pseg_start, nblock)) {
+       if (nilfs_compute_checksum(nilfs, bh_sum, &crc, sizeof(sum->ss_datasum),
+                                  ((u64)nblock << nilfs->ns_blocksize_bits),
+                                  pseg_start, nblock)) {
                ret = NILFS_SEG_FAIL_IO;
                goto failed;
        }
        return ret;
 }
 
-static void *segsum_get(struct super_block *sb, struct buffer_head **pbh,
-                       unsigned int *offset, unsigned int bytes)
+/**
+ * nilfs_read_summary_info - read an item on summary blocks of a log
+ * @nilfs: nilfs object
+ * @pbh: the current buffer head on summary blocks [in, out]
+ * @offset: the current byte offset on summary blocks [in, out]
+ * @bytes: byte size of the item to be read
+ */
+static void *nilfs_read_summary_info(struct the_nilfs *nilfs,
+                                    struct buffer_head **pbh,
+                                    unsigned int *offset, unsigned int bytes)
 {
        void *ptr;
        sector_t blocknr;
        if (bytes > (*pbh)->b_size - *offset) {
                blocknr = (*pbh)->b_blocknr;
                brelse(*pbh);
-               *pbh = sb_bread(sb, blocknr + 1);
+               *pbh = __bread(nilfs->ns_bdev, blocknr + 1,
+                              nilfs->ns_blocksize);
                if (unlikely(!*pbh))
                        return NULL;
                *offset = 0;
        return ptr;
 }
 
-static void segsum_skip(struct super_block *sb, struct buffer_head **pbh,
-                       unsigned int *offset, unsigned int bytes,
-                       unsigned long count)
+/**
+ * nilfs_skip_summary_info - skip items on summary blocks of a log
+ * @nilfs: nilfs object
+ * @pbh: the current buffer head on summary blocks [in, out]
+ * @offset: the current byte offset on summary blocks [in, out]
+ * @bytes: byte size of the item to be skipped
+ * @count: number of items to be skipped
+ */
+static void nilfs_skip_summary_info(struct the_nilfs *nilfs,
+                                   struct buffer_head **pbh,
+                                   unsigned int *offset, unsigned int bytes,
+                                   unsigned long count)
 {
        unsigned int rest_item_in_current_block
                = ((*pbh)->b_size - *offset) / bytes;
                *offset = bytes * (count - (bcnt - 1) * nitem_per_block);
 
                brelse(*pbh);
-               *pbh = sb_bread(sb, blocknr + bcnt);
+               *pbh = __bread(nilfs->ns_bdev, blocknr + bcnt,
+                              nilfs->ns_blocksize);
        }
 }
 
-static int
-collect_blocks_from_segsum(struct nilfs_sb_info *sbi, sector_t sum_blocknr,
-                          struct nilfs_segsum_info *ssi,
-                          struct list_head *head)
+/**
+ * nilfs_scan_dsync_log - get block information of a log written for data sync
+ * @nilfs: nilfs object
+ * @start_blocknr: start block number of the log
+ * @ssi: log summary information
+ * @head: list head to add nilfs_recovery_block struct
+ */
+static int nilfs_scan_dsync_log(struct the_nilfs *nilfs, sector_t start_blocknr,
+                               struct nilfs_segsum_info *ssi,
+                               struct list_head *head)
 {
        struct buffer_head *bh;
        unsigned int offset;
        unsigned long nfinfo = ssi->nfinfo;
-       sector_t blocknr = sum_blocknr + ssi->nsumblk;
+       sector_t blocknr = start_blocknr + ssi->nsumblk;
        ino_t ino;
        int err = -EIO;
 
        if (!nfinfo)
                return 0;
 
-       bh = sb_bread(sbi->s_super, sum_blocknr);
+       bh = __bread(nilfs->ns_bdev, start_blocknr, nilfs->ns_blocksize);
        if (unlikely(!bh))
                goto out;
 
                unsigned long nblocks, ndatablk, nnodeblk;
                struct nilfs_finfo *finfo;
 
-               finfo = segsum_get(sbi->s_super, &bh, &offset, sizeof(*finfo));
+               finfo = nilfs_read_summary_info(nilfs, &bh, &offset,
+                                               sizeof(*finfo));
                if (unlikely(!finfo))
                        goto out;
 
                        struct nilfs_recovery_block *rb;
                        struct nilfs_binfo_v *binfo;
 
-                       binfo = segsum_get(sbi->s_super, &bh, &offset,
-                                          sizeof(*binfo));
+                       binfo = nilfs_read_summary_info(nilfs, &bh, &offset,
+                                                       sizeof(*binfo));
                        if (unlikely(!binfo))
                                goto out;
 
                }
                if (--nfinfo == 0)
                        break;
-               blocknr += nnodeblk; /* always 0 for the data sync segments */
-               segsum_skip(sbi->s_super, &bh, &offset, sizeof(__le64),
-                           nnodeblk);
+               blocknr += nnodeblk; /* always 0 for data sync logs */
+               nilfs_skip_summary_info(nilfs, &bh, &offset, sizeof(__le64),
+                                       nnodeblk);
                if (unlikely(!bh))
                        goto out;
        }
        return err;
 }
 
-static int nilfs_recovery_copy_block(struct nilfs_sb_info *sbi,
+static int nilfs_recovery_copy_block(struct the_nilfs *nilfs,
                                     struct nilfs_recovery_block *rb,
                                     struct page *page)
 {
        struct buffer_head *bh_org;
        void *kaddr;
 
-       bh_org = sb_bread(sbi->s_super, rb->blocknr);
+       bh_org = __bread(nilfs->ns_bdev, rb->blocknr, nilfs->ns_blocksize);
        if (unlikely(!bh_org))
                return -EIO;
 
        return 0;
 }
 
-static int recover_dsync_blocks(struct nilfs_sb_info *sbi,
-                               struct list_head *head,
-                               unsigned long *nr_salvaged_blocks)
+static int nilfs_recover_dsync_blocks(struct the_nilfs *nilfs,
+                                     struct nilfs_sb_info *sbi,
+                                     struct list_head *head,
+                                     unsigned long *nr_salvaged_blocks)
 {
        struct inode *inode;
        struct nilfs_recovery_block *rb, *n;
-       unsigned blocksize = sbi->s_super->s_blocksize;
+       unsigned blocksize = nilfs->ns_blocksize;
        struct page *page;
        loff_t pos;
        int err = 0, err2 = 0;
                if (unlikely(err))
                        goto failed_inode;
 
-               err = nilfs_recovery_copy_block(sbi, rb, page);
+               err = nilfs_recovery_copy_block(nilfs, rb, page);
                if (unlikely(err))
                        goto failed_page;
 
 /**
  * nilfs_do_roll_forward - salvage logical segments newer than the latest
  * checkpoint
+ * @nilfs: nilfs object
  * @sbi: nilfs_sb_info
- * @nilfs: the_nilfs
  * @ri: pointer to a nilfs_recovery_info
  */
 static int nilfs_do_roll_forward(struct the_nilfs *nilfs,
 
        while (segnum != ri->ri_segnum || pseg_start <= ri->ri_pseg_start) {
 
-               ret = load_segment_summary(sbi, pseg_start, seg_seq, &ssi);
+               ret = load_segment_summary(nilfs, pseg_start, seg_seq, &ssi);
                if (ret) {
                        if (ret == NILFS_SEG_FAIL_IO) {
                                err = -EIO;
                        if (!NILFS_SEG_DSYNC(&ssi))
                                goto confused;
 
-                       err = collect_blocks_from_segsum(
-                               sbi, pseg_start, &ssi, &dsync_blocks);
+                       err = nilfs_scan_dsync_log(nilfs, pseg_start, &ssi,
+                                                  &dsync_blocks);
                        if (unlikely(err))
                                goto failed;
                        if (NILFS_SEG_LOGEND(&ssi)) {
-                               err = recover_dsync_blocks(
-                                       sbi, &dsync_blocks, &nsalvaged_blocks);
+                               err = nilfs_recover_dsync_blocks(
+                                       nilfs, sbi, &dsync_blocks,
+                                       &nsalvaged_blocks);
                                if (unlikely(err))
                                        goto failed;
                                state = RF_INIT_ST;
        }
  out:
        dispose_recovery_list(&dsync_blocks);
-       nilfs_detach_writer(sbi->s_nilfs, sbi);
+       nilfs_detach_writer(nilfs, sbi);
        return err;
 
  confused:
 }
 
 static void nilfs_finish_roll_forward(struct the_nilfs *nilfs,
-                                     struct nilfs_sb_info *sbi,
                                      struct nilfs_recovery_info *ri)
 {
        struct buffer_head *bh;
            nilfs_get_segnum_of_block(nilfs, ri->ri_super_root))
                return;
 
-       bh = sb_getblk(sbi->s_super, ri->ri_lsegs_start);
+       bh = __getblk(nilfs->ns_bdev, ri->ri_lsegs_start, nilfs->ns_blocksize);
        BUG_ON(!bh);
        memset(bh->b_data, 0, bh->b_size);
        set_buffer_dirty(bh);
                        goto failed;
                }
 
-               nilfs_finish_roll_forward(nilfs, sbi, ri);
+               nilfs_finish_roll_forward(nilfs, ri);
        }
 
  failed:
 /**
  * nilfs_search_super_root - search the latest valid super root
  * @nilfs: the_nilfs
- * @sbi: nilfs_sb_info
  * @ri: pointer to a nilfs_recovery_info struct to store search results.
  *
  * nilfs_search_super_root() looks for the latest super-root from a partial
  *
  * %-EIO - I/O error
  */
-int nilfs_search_super_root(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi,
+int nilfs_search_super_root(struct the_nilfs *nilfs,
                            struct nilfs_recovery_info *ri)
 {
        struct nilfs_segsum_info ssi;
        /* Read ahead segment */
        b = seg_start;
        while (b <= seg_end)
-               sb_breadahead(sbi->s_super, b++);
+               __breadahead(nilfs->ns_bdev, b++, nilfs->ns_blocksize);
 
        for (;;) {
-               /* Load segment summary */
-               ret = load_segment_summary(sbi, pseg_start, seg_seq, &ssi);
+               ret = load_segment_summary(nilfs, pseg_start, seg_seq, &ssi);
                if (ret) {
                        if (ret == NILFS_SEG_FAIL_IO)
                                goto failed;
                if (pseg_start == seg_start) {
                        nilfs_get_segment_range(nilfs, nextnum, &b, &end);
                        while (b <= end)
-                               sb_breadahead(sbi->s_super, b++);
+                               __breadahead(nilfs->ns_bdev, b++,
+                                            nilfs->ns_blocksize);
                }
                if (!NILFS_SEG_HAS_SR(&ssi)) {
                        if (!ri->ri_lsegs_start && NILFS_SEG_LOGBGN(&ssi)) {