aboutsummaryrefslogtreecommitdiffstats
path: root/fs/ufs/cylinder.c
blob: 2a815665644f30b0d3efb4d632004cada1ddc57f (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
/*
 *  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/ufs_fs.h>
#include <linux/time.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/bitops.h>

#include <asm/byteorder.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];
}