C++ UCPI_UBH函数代码示例

static u64 ufs_alloccg_block(struct inode *inode,
			     struct ufs_cg_private_info *ucpi,
			     u64 goal, int *err)
{
	struct super_block * sb;
	struct ufs_sb_private_info * uspi;
	struct ufs_super_block_first * usb1;
	struct ufs_cylinder_group * ucg;
	u64 result, blkno;

	UFSD("ENTER, goal %llu\n", (unsigned long long)goal);

	sb = inode->i_sb;
	uspi = UFS_SB(sb)->s_uspi;
	usb1 = ubh_get_usb_first(uspi);
	ucg = ubh_get_ucg(UCPI_UBH(ucpi));

	if (goal == 0) {
		goal = ucpi->c_rotor;
		goto norot;
	}
	goal = ufs_blknum (goal);
	goal = ufs_dtogd(uspi, goal);
	
	/*
	 * If the requested block is available, use it.
	 */
	if (ubh_isblockset(UCPI_UBH(ucpi), ucpi->c_freeoff, ufs_fragstoblks(goal))) {
		result = goal;
		goto gotit;
	}
	
norot:	
	result = ufs_bitmap_search (sb, ucpi, goal, uspi->s_fpb);
	if (result == INVBLOCK)
		return INVBLOCK;
	ucpi->c_rotor = result;
gotit:
	blkno = ufs_fragstoblks(result);
	ubh_clrblock (UCPI_UBH(ucpi), ucpi->c_freeoff, blkno);
	if ((UFS_SB(sb)->s_flags & UFS_CG_MASK) == UFS_CG_44BSD)
		ufs_clusteracct (sb, ucpi, blkno, -1);

	fs32_sub(sb, &ucg->cg_cs.cs_nbfree, 1);
	uspi->cs_total.cs_nbfree--;
	fs32_sub(sb, &UFS_SB(sb)->fs_cs(ucpi->c_cgx).cs_nbfree, 1);

	if (uspi->fs_magic != UFS2_MAGIC) {
		unsigned cylno = ufs_cbtocylno((unsigned)result);

		fs16_sub(sb, &ubh_cg_blks(ucpi, cylno,
					  ufs_cbtorpos((unsigned)result)), 1);
		fs32_sub(sb, &ubh_cg_blktot(ucpi, cylno), 1);
	}
	
	UFSD("EXIT, result %llu\n", (unsigned long long)result);

	return result;
}

/*
 * Read cylinder group into cache. The memory space for ufs_cg_private_info
 * structure is already allocated during ufs_read_super.
 */
static void ufs_read_cylinder (struct super_block * sb,
	unsigned cgno, unsigned bitmap_nr)
{
	struct ufs_sb_info * sbi = UFS_SB(sb);
	struct ufs_sb_private_info * uspi;
	struct ufs_cg_private_info * ucpi;
	struct ufs_cylinder_group * ucg;
	unsigned i, j;

	UFSD("ENTER, cgno %u, bitmap_nr %u\n", cgno, bitmap_nr);
	uspi = sbi->s_uspi;
	ucpi = sbi->s_ucpi[bitmap_nr];
	ucg = (struct ufs_cylinder_group *)sbi->s_ucg[cgno]->b_data;

	UCPI_UBH(ucpi)->fragment = ufs_cgcmin(cgno);
	UCPI_UBH(ucpi)->count = uspi->s_cgsize >> sb->s_blocksize_bits;
	/*
	 * We have already the first fragment of cylinder group block in buffer
	 */
	UCPI_UBH(ucpi)->bh[0] = sbi->s_ucg[cgno];
	for (i = 1; i < UCPI_UBH(ucpi)->count; i++)
		if (!(UCPI_UBH(ucpi)->bh[i] = sb_bread(sb, UCPI_UBH(ucpi)->fragment + i)))
			goto failed;
	sbi->s_cgno[bitmap_nr] = cgno;
			
	ucpi->c_cgx	= fs32_to_cpu(sb, ucg->cg_cgx);
	ucpi->c_ncyl	= fs16_to_cpu(sb, ucg->cg_ncyl);
	ucpi->c_niblk	= fs16_to_cpu(sb, ucg->cg_niblk);
	ucpi->c_ndblk	= fs32_to_cpu(sb, ucg->cg_ndblk);
	ucpi->c_rotor	= fs32_to_cpu(sb, ucg->cg_rotor);
	ucpi->c_frotor	= fs32_to_cpu(sb, ucg->cg_frotor);
	ucpi->c_irotor	= fs32_to_cpu(sb, ucg->cg_irotor);
	ucpi->c_btotoff	= fs32_to_cpu(sb, ucg->cg_btotoff);
	ucpi->c_boff	= fs32_to_cpu(sb, ucg->cg_boff);
	ucpi->c_iusedoff = fs32_to_cpu(sb, ucg->cg_iusedoff);
	ucpi->c_freeoff	= fs32_to_cpu(sb, ucg->cg_freeoff);
	ucpi->c_nextfreeoff = fs32_to_cpu(sb, ucg->cg_nextfreeoff);
	ucpi->c_clustersumoff = fs32_to_cpu(sb, ucg->cg_u.cg_44.cg_clustersumoff);
	ucpi->c_clusteroff = fs32_to_cpu(sb, ucg->cg_u.cg_44.cg_clusteroff);
	ucpi->c_nclusterblks = fs32_to_cpu(sb, ucg->cg_u.cg_44.cg_nclusterblks);
	UFSD("EXIT\n");
	return;	
	
failed:
	for (j = 1; j < i; j++)
		brelse (sbi->s_ucg[j]);
	sbi->s_cgno[bitmap_nr] = UFS_CGNO_EMPTY;
	ufs_error (sb, "ufs_read_cylinder", "can't read cylinder group block %u", cgno);
}

/*
 * Remove cylinder group from cache, doesn't release memory
 * allocated for cylinder group (this is done at ufs_put_super only).
 */
void ufs_put_cylinder (struct super_block * sb, unsigned bitmap_nr)
{
	struct ufs_sb_info * sbi = UFS_SB(sb);
	struct ufs_sb_private_info * uspi; 
	struct ufs_cg_private_info * ucpi;
	struct ufs_cylinder_group * ucg;
	unsigned i;

	UFSD("ENTER, bitmap_nr %u\n", bitmap_nr);

	uspi = sbi->s_uspi;
	if (sbi->s_cgno[bitmap_nr] == UFS_CGNO_EMPTY) {
		UFSD("EXIT\n");
		return;
	}
	ucpi = sbi->s_ucpi[bitmap_nr];
	ucg = ubh_get_ucg(UCPI_UBH(ucpi));

	if (uspi->s_ncg > UFS_MAX_GROUP_LOADED && bitmap_nr >= sbi->s_cg_loaded) {
		ufs_panic (sb, "ufs_put_cylinder", "internal error");
		return;
	}
	/*
	 * rotor is not so important data, so we put it to disk 
	 * at the end of working with cylinder
	 */
	ucg->cg_rotor = cpu_to_fs32(sb, ucpi->c_rotor);
	ucg->cg_frotor = cpu_to_fs32(sb, ucpi->c_frotor);
	ucg->cg_irotor = cpu_to_fs32(sb, ucpi->c_irotor);
	ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
	for (i = 1; i < UCPI_UBH(ucpi)->count; i++) {
		brelse (UCPI_UBH(ucpi)->bh[i]);
	}

	sbi->s_cgno[bitmap_nr] = UFS_CGNO_EMPTY;
	UFSD("EXIT\n");
}

/*
 * NOTE! When we get the inode, we're the only people
 * that have access to it, and as such there are no
 * race conditions we have to worry about. The inode
 * is not on the hash-lists, and it cannot be reached
 * through the filesystem because the directory entry
 * has been deleted earlier.
 *
 * HOWEVER: we must make sure that we get no aliases,
 * which means that we have to call "clear_inode()"
 * _before_ we mark the inode not in use in the inode
 * bitmaps. Otherwise a newly created file might use
 * the same inode number (not actually the same pointer
 * though), and then we'd have two inodes sharing the
 * same inode number and space on the harddisk.
 */
void ufs_free_inode (struct inode * inode)
{
    struct super_block * sb;
    struct ufs_sb_private_info * uspi;
    struct ufs_super_block_first * usb1;
    struct ufs_cg_private_info * ucpi;
    struct ufs_cylinder_group * ucg;
    int is_directory;
    unsigned ino, cg, bit;
    
    UFSD("ENTER, ino %lu\n", inode->i_ino);

    sb = inode->i_sb;
    uspi = UFS_SB(sb)->s_uspi;
    usb1 = ubh_get_usb_first(uspi);
    
    ino = inode->i_ino;

    lock_super (sb);

    if (!((ino > 1) && (ino < (uspi->s_ncg * uspi->s_ipg )))) {
        ufs_warning(sb, "ufs_free_inode", "reserved inode or nonexistent inode %u\n", ino);
        unlock_super (sb);
        return;
    }
    
    cg = ufs_inotocg (ino);
    bit = ufs_inotocgoff (ino);
    ucpi = ufs_load_cylinder (sb, cg);
    if (!ucpi) {
        unlock_super (sb);
        return;
    }
    ucg = ubh_get_ucg(UCPI_UBH(ucpi));
    if (!ufs_cg_chkmagic(sb, ucg))
        ufs_panic (sb, "ufs_free_fragments", "internal error, bad cg magic number");

    ucg->cg_time = cpu_to_fs32(sb, get_seconds());

    is_directory = S_ISDIR(inode->i_mode);

    DQUOT_FREE_INODE(inode);
    DQUOT_DROP(inode);

    clear_inode (inode);

    if (ubh_isclr (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit))
        ufs_error(sb, "ufs_free_inode", "bit already cleared for inode %u", ino);
    else {
        ubh_clrbit (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit);
        if (ino < ucpi->c_irotor)
            ucpi->c_irotor = ino;
        fs32_add(sb, &ucg->cg_cs.cs_nifree, 1);
        uspi->cs_total.cs_nifree++;
        fs32_add(sb, &UFS_SB(sb)->fs_cs(cg).cs_nifree, 1);

        if (is_directory) {
            fs32_sub(sb, &ucg->cg_cs.cs_ndir, 1);
            uspi->cs_total.cs_ndir--;
            fs32_sub(sb, &UFS_SB(sb)->fs_cs(cg).cs_ndir, 1);
        }
    }

    ubh_mark_buffer_dirty (USPI_UBH(uspi));
    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));
    }
    
    sb->s_dirt = 1;
    unlock_super (sb);
    UFSD("EXIT\n");
}

/*
 * There are two policies for allocating an inode.  If the new inode is
 * a directory, then a forward search is made for a block group with both
 * free space and a low directory-to-inode ratio; if that fails, then of
 * the groups with above-average free space, that group with the fewest
 * directories already is chosen.
 *
 * For other inodes, search forward from the parent directory's block
 * group to find a free inode.
 */
struct inode * ufs_new_inode(struct inode * dir, int mode)
{
    struct super_block * sb;
    struct ufs_sb_info * sbi;
    struct ufs_sb_private_info * uspi;
    struct ufs_super_block_first * usb1;
    struct ufs_cg_private_info * ucpi;
    struct ufs_cylinder_group * ucg;
    struct inode * inode;
    unsigned cg, bit, i, j, start;
    struct ufs_inode_info *ufsi;
    int err = -ENOSPC;

    UFSD("ENTER\n");
    
    /* Cannot create files in a deleted directory */
    if (!dir || !dir->i_nlink)
        return ERR_PTR(-EPERM);
    sb = dir->i_sb;
    inode = new_inode(sb);
    if (!inode)
        return ERR_PTR(-ENOMEM);
    ufsi = UFS_I(inode);
    sbi = UFS_SB(sb);
    uspi = sbi->s_uspi;
    usb1 = ubh_get_usb_first(uspi);

    lock_super (sb);

    /*
     * Try to place the inode in its parent directory
     */
    i = ufs_inotocg(dir->i_ino);
    if (sbi->fs_cs(i).cs_nifree) {
        cg = i;
        goto cg_found;
    }

    /*
     * Use a quadratic hash to find a group with a free inode
     */
    for ( j = 1; j < uspi->s_ncg; j <<= 1 ) {
        i += j;
        if (i >= uspi->s_ncg)
            i -= uspi->s_ncg;
        if (sbi->fs_cs(i).cs_nifree) {
            cg = i;
            goto cg_found;
        }
    }

    /*
     * That failed: try linear search for a free inode
     */
    i = ufs_inotocg(dir->i_ino) + 1;
    for (j = 2; j < uspi->s_ncg; j++) {
        i++;
        if (i >= uspi->s_ncg)
            i = 0;
        if (sbi->fs_cs(i).cs_nifree) {
            cg = i;
            goto cg_found;
        }
    }

    goto failed;

cg_found:
    ucpi = ufs_load_cylinder (sb, cg);
    if (!ucpi) {
        err = -EIO;
        goto failed;
    }
    ucg = ubh_get_ucg(UCPI_UBH(ucpi));
    if (!ufs_cg_chkmagic(sb, ucg)) 
        ufs_panic (sb, "ufs_new_inode", "internal error, bad cg magic number");

    start = ucpi->c_irotor;
    bit = ubh_find_next_zero_bit (UCPI_UBH(ucpi), ucpi->c_iusedoff, uspi->s_ipg, start);
    if (!(bit < uspi->s_ipg)) {
        bit = ubh_find_first_zero_bit (UCPI_UBH(ucpi), ucpi->c_iusedoff, start);
        if (!(bit < start)) {
            ufs_error (sb, "ufs_new_inode",
                "cylinder group %u corrupted - error in inode bitmap\n", cg);
            err = -EIO;
            goto failed;
        }
    }
    UFSD("start = %u, bit = %u, ipg = %u\n", start, bit, uspi->s_ipg);
    if (ubh_isclr (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit))
//.........这里部分代码省略.........