C++ sb_getblk函数代码示例

struct buffer_head *udf_tgetblk(struct super_block *sb, int block)
{
	if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
		return sb_getblk(sb, udf_fixed_to_variable(block));
	else
		return sb_getblk(sb, block);
}

static int read_bitmaps (struct super_block * s)
{
    int i, bmp;

    SB_AP_BITMAP (s) = vmalloc (sizeof (struct reiserfs_bitmap_info) * SB_BMAP_NR(s));
    if (SB_AP_BITMAP (s) == 0)
      return 1;
    memset (SB_AP_BITMAP (s), 0, sizeof (struct reiserfs_bitmap_info) * SB_BMAP_NR(s));

    for (i = 0, bmp = REISERFS_DISK_OFFSET_IN_BYTES / s->s_blocksize + 1;
 	 i < SB_BMAP_NR(s); i++, bmp = s->s_blocksize * 8 * i) {
      SB_AP_BITMAP (s)[i].bh = sb_getblk (s, bmp);
      if (!buffer_uptodate(SB_AP_BITMAP(s)[i].bh))
	ll_rw_block(READ, 1, &SB_AP_BITMAP(s)[i].bh); 
    }
    for (i = 0; i < SB_BMAP_NR(s); i++) {
      wait_on_buffer(SB_AP_BITMAP (s)[i].bh);
      if (!buffer_uptodate(SB_AP_BITMAP(s)[i].bh)) {
	reiserfs_warning("sh-2029: reiserfs read_bitmaps: "
			 "bitmap block (#%lu) reading failed\n",
			 SB_AP_BITMAP(s)[i].bh->b_blocknr);
	for (i = 0; i < SB_BMAP_NR(s); i++)
	  brelse(SB_AP_BITMAP(s)[i].bh);
	vfree(SB_AP_BITMAP(s));
	SB_AP_BITMAP(s) = NULL;
	return 1;
      }
      load_bitmap_info_data (s, SB_AP_BITMAP (s) + i);
    }   
    return 0;
}

static struct buffer_head *
read_block_bitmap(struct super_block *sb, unsigned int block_group)
{
	struct ext2_group_desc * desc;
	struct buffer_head * bh = NULL;
	ext2_fsblk_t bitmap_blk;

	desc = ext2_get_group_desc(sb, block_group, NULL);
	if (!desc)
		return NULL;
	bitmap_blk = le32_to_cpu(desc->bg_block_bitmap);
	bh = sb_getblk(sb, bitmap_blk);
	if (unlikely(!bh)) {
		ext2_error(sb, __func__,
			    "Cannot read block bitmap - "
			    "block_group = %d, block_bitmap = %u",
			    block_group, le32_to_cpu(desc->bg_block_bitmap));
		return NULL;
	}
	if (likely(bh_uptodate_or_lock(bh)))
		return bh;

	if (bh_submit_read(bh) < 0) {
		brelse(bh);
		ext2_error(sb, __func__,
			    "Cannot read block bitmap - "
			    "block_group = %d, block_bitmap = %u",
			    block_group, le32_to_cpu(desc->bg_block_bitmap));
		return NULL;
	}

	ext2_valid_block_bitmap(sb, desc, block_group, bh);
	return bh;
}

/*
 * Nullify new chunk of inodes,
 * BSD people also set ui_gen field of inode
 * during nullification, but we not care about
 * that because of linux ufs do not support NFS
 */
static void ufs2_init_inodes_chunk(struct super_block *sb,
                   struct ufs_cg_private_info *ucpi,
                   struct ufs_cylinder_group *ucg)
{
    struct buffer_head *bh;
    struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
    sector_t beg = uspi->s_sbbase +
        ufs_inotofsba(ucpi->c_cgx * uspi->s_ipg +
                  fs32_to_cpu(sb, ucg->cg_u.cg_u2.cg_initediblk));
    sector_t end = beg + uspi->s_fpb;

    UFSD("ENTER cgno %d\n", ucpi->c_cgx);

    for (; beg < end; ++beg) {
        bh = sb_getblk(sb, beg);
        lock_buffer(bh);
        memset(bh->b_data, 0, sb->s_blocksize);
        set_buffer_uptodate(bh);
        mark_buffer_dirty(bh);
        unlock_buffer(bh);
        if (sb->s_flags & MS_SYNCHRONOUS)
            sync_dirty_buffer(bh);
        brelse(bh);
    }

    fs32_add(sb, &ucg->cg_u.cg_u2.cg_initediblk, uspi->s_inopb);
    ubh_mark_buffer_dirty(UCPI_UBH(ucpi));
    if (sb->s_flags & MS_SYNCHRONOUS) {
        ubh_ll_rw_block(SWRITE, UCPI_UBH(ucpi));
        ubh_wait_on_buffer(UCPI_UBH(ucpi));
    }

    UFSD("EXIT\n");
}

void sysv_free_block(struct super_block * sb, sysv_zone_t nr)
{
	struct sysv_sb_info * sbi = SYSV_SB(sb);
	struct buffer_head * bh;
	sysv_zone_t *blocks = sbi->s_bcache;
	unsigned count;
	unsigned block = fs32_to_cpu(sbi, nr);

	/*
	 * This code does not work at all for AFS (it has a bitmap
	 * free list).  As AFS is supposed to be read-only no one
	 * should call this for an AFS filesystem anyway...
	 */
	if (sbi->s_type == FSTYPE_AFS)
		return;

	if (block < sbi->s_firstdatazone || block >= sbi->s_nzones) {
		printk("sysv_free_block: trying to free block not in datazone\n");
		return;
	}

	mutex_lock(&sbi->s_lock);
	count = fs16_to_cpu(sbi, *sbi->s_bcache_count);

	if (count > sbi->s_flc_size) {
	  printk("sysv_free_block: flc_count %d > flc_size %d\n", count, sbi->s_flc_size);
		mutex_unlock(&sbi->s_lock);
		return;
	}
	/* If the free list head in super-block is full, it is copied
	 * into this block being freed, ditto if it's completely empty
	 * (applies only on Coherent).
	 */
	if (count == sbi->s_flc_size || count == 0) {
		block += sbi->s_block_base;
		bh = sb_getblk(sb, block);
		if (!bh) {
			printk("sysv_free_block: getblk() failed\n");
			mutex_unlock(&sbi->s_lock);
			return;
		}
		memset(bh->b_data, 0, sb->s_blocksize);
		*(__fs16*)bh->b_data = cpu_to_fs16(sbi, count);
		memcpy(get_chunk(sb,bh), blocks, count * sizeof(sysv_zone_t));
		mark_buffer_dirty(bh);
		set_buffer_uptodate(bh);
		brelse(bh);
		count = 0;
	}
	sbi->s_bcache[count++] = nr;

	*sbi->s_bcache_count = cpu_to_fs16(sbi, count);
	fs32_add(sbi, sbi->s_free_blocks, 1);
	dirty_sb(sb);
	mutex_unlock(&sbi->s_lock);
}

/**
 * nilfs_move_2nd_super - relocate secondary super block
 * @sb: super block instance
 * @sb2off: new offset of the secondary super block (in bytes)
 */
static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
{
	struct the_nilfs *nilfs = sb->s_fs_info;
	struct buffer_head *nsbh;
	struct nilfs_super_block *nsbp;
	sector_t blocknr, newblocknr;
	unsigned long offset;
	int sb2i;  /* array index of the secondary superblock */
	int ret = 0;

	/* nilfs->ns_sem must be locked by the caller. */
	if (nilfs->ns_sbh[1] &&
	    nilfs->ns_sbh[1]->b_blocknr > nilfs->ns_first_data_block) {
		sb2i = 1;
		blocknr = nilfs->ns_sbh[1]->b_blocknr;
	} else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
		sb2i = 0;
		blocknr = nilfs->ns_sbh[0]->b_blocknr;
	} else {
		sb2i = -1;
		blocknr = 0;
	}
	if (sb2i >= 0 && (u64)blocknr << nilfs->ns_blocksize_bits == sb2off)
		goto out;  /* super block location is unchanged */

	/* Get new super block buffer */
	newblocknr = sb2off >> nilfs->ns_blocksize_bits;
	offset = sb2off & (nilfs->ns_blocksize - 1);
	nsbh = sb_getblk(sb, newblocknr);
	if (!nsbh) {
		nilfs_msg(sb, KERN_WARNING,
			  "unable to move secondary superblock to block %llu",
			  (unsigned long long)newblocknr);
		ret = -EIO;
		goto out;
	}
	nsbp = (void *)nsbh->b_data + offset;
	memset(nsbp, 0, nilfs->ns_blocksize);

	if (sb2i >= 0) {
		memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
		brelse(nilfs->ns_sbh[sb2i]);
		nilfs->ns_sbh[sb2i] = nsbh;
		nilfs->ns_sbp[sb2i] = nsbp;
	} else if (nilfs->ns_sbh[0]->b_blocknr < nilfs->ns_first_data_block) {
		/* secondary super block will be restored to index 1 */
		nilfs->ns_sbh[1] = nsbh;
		nilfs->ns_sbp[1] = nsbp;
	} else {
		brelse(nsbh);
	}
out:
	return ret;
}

/* Write to quotafile */
static ssize_t ext2_quota_write(struct super_block *sb, int type,
				const char *data, size_t len, loff_t off)
{
	struct inode *inode = sb_dqopt(sb)->files[type];
	sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
	int err = 0;
	int offset = off & (sb->s_blocksize - 1);
	int tocopy;
	size_t towrite = len;
	struct buffer_head tmp_bh;
	struct buffer_head *bh;

	mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
	while (towrite > 0) {
		tocopy = sb->s_blocksize - offset < towrite ?
				sb->s_blocksize - offset : towrite;

		tmp_bh.b_state = 0;
		err = ext2_get_block(inode, blk, &tmp_bh, 1);
		if (err < 0)
			goto out;
		if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
			bh = sb_bread(sb, tmp_bh.b_blocknr);
		else
			bh = sb_getblk(sb, tmp_bh.b_blocknr);
		if (!bh) {
			err = -EIO;
			goto out;
		}
		lock_buffer(bh);
		memcpy(bh->b_data+offset, data, tocopy);
		flush_dcache_page(bh->b_page);
		set_buffer_uptodate(bh);
		mark_buffer_dirty(bh);
		unlock_buffer(bh);
		brelse(bh);
		offset = 0;
		towrite -= tocopy;
		data += tocopy;
		blk++;
	}
out:
	if (len == towrite) {
		mutex_unlock(&inode->i_mutex);
		return err;
	}
	if (inode->i_size < off+len-towrite)
		i_size_write(inode, off+len-towrite);
	inode->i_version++;
	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
	mark_inode_dirty(inode);
	mutex_unlock(&inode->i_mutex);
	return len - towrite;
}

static struct buffer_head *qnx4_getblk(struct inode *inode, int nr,
				       int create)
{
	struct buffer_head *result = NULL;

	if ( nr >= 0 )
		nr = qnx4_block_map( inode, nr );
	if (nr) {
		result = sb_getblk(inode->i_sb, nr);
		return result;
	}
	return NULL;
}

// desperately need ERR_PTR return here to distinguish between
// ENOMEM, which should be impossible but when it happens we
// need to do something reasonable, or ENOSPC which we must
// just report and keep going without a fuss.
static struct buffer_head *new_block(struct btree *btree)
{
	block_t block;
	int err = btree->ops->balloc(btree->sb, 1, &block);
	if (err)
		return NULL; // ERR_PTR me!!!
	struct buffer_head *buffer = sb_getblk(vfs_sb(btree->sb), block);
	if (!buffer)
		return NULL;
	memset(bufdata(buffer), 0, bufsize(buffer));
	mark_buffer_dirty(buffer);
	return buffer;
}

void *hpfs_get_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp)
{
	struct buffer_head *bh;
	/*return hpfs_map_sector(s, secno, bhp, 0);*/

	cond_resched();

	if ((*bhp = bh = sb_getblk(s, secno)) != NULL) {
		if (!buffer_uptodate(bh)) wait_on_buffer(bh);
		set_buffer_uptodate(bh);
		return bh->b_data;
	} else {
		printk("HPFS: hpfs_get_sector: getblk failed\n");
		return NULL;
	}
}

/*
 * Read the MMP block. It _must_ be read from disk and hence we clear the
 * uptodate flag on the buffer.
 */
static int read_mmp_block(struct super_block *sb, struct buffer_head **bh,
			  ext4_fsblk_t mmp_block)
{
	struct mmp_struct *mmp;
	int ret;

	if (*bh)
		clear_buffer_uptodate(*bh);

	/* This would be sb_bread(sb, mmp_block), except we need to be sure
	 * that the MD RAID device cache has been bypassed, and that the read
	 * is not blocked in the elevator. */
	if (!*bh) {
		*bh = sb_getblk(sb, mmp_block);
		if (!*bh) {
			ret = -ENOMEM;
			goto warn_exit;
		}
	}

	get_bh(*bh);
	lock_buffer(*bh);
	(*bh)->b_end_io = end_buffer_read_sync;
	submit_bh(READ_SYNC | REQ_META | REQ_PRIO, *bh);
	wait_on_buffer(*bh);
	if (!buffer_uptodate(*bh)) {
		ret = -EIO;
		goto warn_exit;
	}
	mmp = (struct mmp_struct *)((*bh)->b_data);
	if (le32_to_cpu(mmp->mmp_magic) != EXT4_MMP_MAGIC) {
		ret = -EFSCORRUPTED;
		goto warn_exit;
	}
	if (!ext4_mmp_csum_verify(sb, mmp)) {
		ret = -EFSBADCRC;
		goto warn_exit;
	}
	return 0;
warn_exit:
	brelse(*bh);
	*bh = NULL;
	ext4_warning(sb, "Error %d while reading MMP block %llu",
		     ret, mmp_block);
	return ret;
}

void *hpfs_get_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp)
{
	struct buffer_head *bh;
	/*return hpfs_map_sector(s, secno, bhp, 0);*/

	hpfs_lock_assert(s);

	cond_resched();

	if ((*bhp = bh = sb_getblk(s, secno)) != NULL) {
		if (!buffer_uptodate(bh)) wait_on_buffer(bh);
		set_buffer_uptodate(bh);
		return bh->b_data;
	} else {
		pr_err("%s(): getblk failed\n", __func__);
		return NULL;
	}
}

/*
 * hfs_buffer_get()
 *
 * Return a buffer for the 'block'th block of the media.
 * If ('read'==0) then the buffer is not read from disk.
 */
hfs_buffer hfs_buffer_get(hfs_sysmdb sys_mdb, int block, int read) {
	hfs_buffer tmp = HFS_BAD_BUFFER;

	if (read) {
		tmp = sb_bread(sys_mdb, block);
	} else {
		tmp = sb_getblk(sys_mdb, block);
		if (tmp) {
			mark_buffer_uptodate(tmp, 1);
		}
	}
	if (!tmp) {
		hfs_error("hfs_fs: unable to read block 0x%08x from dev %s\n",
			  block, hfs_mdb_name(sys_mdb));
	}

	return tmp;
}

static int32_t
lnx_bget(tarfs_io_t *iop, uint64_t blkno)
{
	struct super_block *sb;
	struct buffer_head *bh;

	if (iop == NULL) {
		return -EINVAL;
	}
 	sb = iop->io_dev;
	iop->io_blkno = blkno;
	bh = sb_getblk(sb, iop->io_blkno);
	if (bh == NULL) {
		return -EIO;
	}
	iop->io_bh = bh;
	iop->io_data = bh->b_data;
	return 0;
}

/*
 * Read the MMP block. It _must_ be read from disk and hence we clear the
 * uptodate flag on the buffer.
 */
static int read_mmp_block(struct super_block *sb, struct buffer_head **bh,
			  ext4_fsblk_t mmp_block)
{
	struct mmp_struct *mmp;

	if (*bh)
		clear_buffer_uptodate(*bh);

	/* This would be sb_bread(sb, mmp_block), except we need to be sure
	 * that the MD RAID device cache has been bypassed, and that the read
	 * is not blocked in the elevator. */
	if (!*bh)
		*bh = sb_getblk(sb, mmp_block);
	if (!*bh)
		return -ENOMEM;
	if (*bh) {
		get_bh(*bh);
		lock_buffer(*bh);
		(*bh)->b_end_io = end_buffer_read_sync;
#ifdef FEATURE_STORAGE_META_LOG
		if( (*bh) && (*bh)->b_bdev && (*bh)->b_bdev->bd_disk)
			set_metadata_rw_status((*bh)->b_bdev->bd_disk->first_minor, WAIT_READ_CNT);
#endif
		submit_bh(READ_SYNC | REQ_META | REQ_PRIO, *bh);
		wait_on_buffer(*bh);
		if (!buffer_uptodate(*bh)) {
			brelse(*bh);
			*bh = NULL;
		}
	}
	if (unlikely(!*bh)) {
		ext4_warning(sb, "Error while reading MMP block %llu",
			     mmp_block);
		return -EIO;
	}

	mmp = (struct mmp_struct *)((*bh)->b_data);
	if (le32_to_cpu(mmp->mmp_magic) != EXT4_MMP_MAGIC ||
	    !ext4_mmp_csum_verify(sb, mmp))
		return -EINVAL;

	return 0;
}