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DEFINITIONS
This source file includes following definitions.
- ufs_read_cylinder
- ufs_put_cylinder
- ufs_load_cylinder
/*
* 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];
}