/* *  linux/fs/ufs/cylinder.c * * Copyright (C) 1998 * Daniel Pirkl <daniel.pirkl@email.cz> * Charles University, Faculty of Mathematics and Physics * *  ext2 - inode (block) bitmap caching inspired */#include <linux/fs.h>#include <linux/time.h>#include <linux/stat.h>#include <linux/string.h>#include <linux/bitops.h>#include <asm/byteorder.h>#include "ufs_fs.h"#include "ufs.h"#include "swab.h"#include "util.h"/* * 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");}/* * Find cylinder group in cache and return it as pointer. * If cylinder group is not in cache, we will load it from disk. * * The cache is managed by LRU algorithm.  */struct ufs_cg_private_info * ufs_load_cylinder (	struct super_block * sb, unsigned cgno){	struct ufs_sb_info * sbi = UFS_SB(sb);	struct ufs_sb_private_info * uspi;	struct ufs_cg_private_info * ucpi;	unsigned cg, i, j;	UFSD("ENTER, cgno %u\n", cgno);	uspi = sbi->s_uspi;	if (cgno >= uspi->s_ncg) {		ufs_panic (sb, "ufs_load_cylinder", "internal error, high number of cg");		return NULL;	}	/*	 * Cylinder group number cg it in cache and it was last used	 */	if (sbi->s_cgno[0] == cgno) {		UFSD("EXIT\n");		return sbi->s_ucpi[0];	}	/*	 * Number of cylinder groups is not higher than UFS_MAX_GROUP_LOADED	 */	if (uspi->s_ncg <= UFS_MAX_GROUP_LOADED) {		if (sbi->s_cgno[cgno] != UFS_CGNO_EMPTY) {			if (sbi->s_cgno[cgno] != cgno) {				ufs_panic (sb, "ufs_load_cylinder", "internal error, wrong number of cg in cache");				UFSD("EXIT (FAILED)\n");				return NULL;			}			else {				UFSD("EXIT\n");				return sbi->s_ucpi[cgno];			}		} else {			ufs_read_cylinder (sb, cgno, cgno);			UFSD("EXIT\n");			return sbi->s_ucpi[cgno];		}	}	/*	 * Cylinder group number cg is in cache but it was not last used, 	 * we will move to the first position	 */	for (i = 0; i < sbi->s_cg_loaded && sbi->s_cgno[i] != cgno; i++);	if (i < sbi->s_cg_loaded && sbi->s_cgno[i] == cgno) {		cg = sbi->s_cgno[i];		ucpi = sbi->s_ucpi[i];		for (j = i; j > 0; j--) {			sbi->s_cgno[j] = sbi->s_cgno[j-1];			sbi->s_ucpi[j] = sbi->s_ucpi[j-1];		}		sbi->s_cgno[0] = cg;		sbi->s_ucpi[0] = ucpi;	/*	 * Cylinder group number cg is not in cache, we will read it from disk	 * and put it to the first position	 */	} else {		if (sbi->s_cg_loaded < UFS_MAX_GROUP_LOADED)			sbi->s_cg_loaded++;		else			ufs_put_cylinder (sb, UFS_MAX_GROUP_LOADED-1);		ucpi = sbi->s_ucpi[sbi->s_cg_loaded - 1];		for (j = sbi->s_cg_loaded - 1; j > 0; j--) {			sbi->s_cgno[j] = sbi->s_cgno[j-1];			sbi->s_ucpi[j] = sbi->s_ucpi[j-1];		}		sbi->s_ucpi[0] = ucpi;		ufs_read_cylinder (sb, cgno, 0);	}	UFSD("EXIT\n");	return sbi->s_ucpi[0];}