1 /*
2 * linux/fs/ufs/cylinder.c
3 *
4 * Copyright (C) 1998
5 * Daniel Pirkl <daniel.pirkl@email.cz>
6 * Charles University, Faculty of Mathematics and Physics
7 *
8 * ext2 - inode (block) bitmap caching inspired
9 */
10
11 #include <linux/fs.h>
12 #include <linux/time.h>
13 #include <linux/stat.h>
14 #include <linux/string.h>
15 #include <linux/bitops.h>
16
17 #include <asm/byteorder.h>
18
19 #include "ufs_fs.h"
20 #include "ufs.h"
21 #include "swab.h"
22 #include "util.h"
23
24 /*
25 * Read cylinder group into cache. The memory space for ufs_cg_private_info
26 * structure is already allocated during ufs_read_super.
27 */
ufs_read_cylinder(struct super_block * sb,unsigned cgno,unsigned bitmap_nr)28 static void ufs_read_cylinder (struct super_block * sb,
29 unsigned cgno, unsigned bitmap_nr)
30 {
31 struct ufs_sb_info * sbi = UFS_SB(sb);
32 struct ufs_sb_private_info * uspi;
33 struct ufs_cg_private_info * ucpi;
34 struct ufs_cylinder_group * ucg;
35 unsigned i, j;
36
37 UFSD("ENTER, cgno %u, bitmap_nr %u\n", cgno, bitmap_nr);
38 uspi = sbi->s_uspi;
39 ucpi = sbi->s_ucpi[bitmap_nr];
40 ucg = (struct ufs_cylinder_group *)sbi->s_ucg[cgno]->b_data;
41
42 UCPI_UBH(ucpi)->fragment = ufs_cgcmin(cgno);
43 UCPI_UBH(ucpi)->count = uspi->s_cgsize >> sb->s_blocksize_bits;
44 /*
45 * We have already the first fragment of cylinder group block in buffer
46 */
47 UCPI_UBH(ucpi)->bh[0] = sbi->s_ucg[cgno];
48 for (i = 1; i < UCPI_UBH(ucpi)->count; i++)
49 if (!(UCPI_UBH(ucpi)->bh[i] = sb_bread(sb, UCPI_UBH(ucpi)->fragment + i)))
50 goto failed;
51 sbi->s_cgno[bitmap_nr] = cgno;
52
53 ucpi->c_cgx = fs32_to_cpu(sb, ucg->cg_cgx);
54 ucpi->c_ncyl = fs16_to_cpu(sb, ucg->cg_ncyl);
55 ucpi->c_niblk = fs16_to_cpu(sb, ucg->cg_niblk);
56 ucpi->c_ndblk = fs32_to_cpu(sb, ucg->cg_ndblk);
57 ucpi->c_rotor = fs32_to_cpu(sb, ucg->cg_rotor);
58 ucpi->c_frotor = fs32_to_cpu(sb, ucg->cg_frotor);
59 ucpi->c_irotor = fs32_to_cpu(sb, ucg->cg_irotor);
60 ucpi->c_btotoff = fs32_to_cpu(sb, ucg->cg_btotoff);
61 ucpi->c_boff = fs32_to_cpu(sb, ucg->cg_boff);
62 ucpi->c_iusedoff = fs32_to_cpu(sb, ucg->cg_iusedoff);
63 ucpi->c_freeoff = fs32_to_cpu(sb, ucg->cg_freeoff);
64 ucpi->c_nextfreeoff = fs32_to_cpu(sb, ucg->cg_nextfreeoff);
65 ucpi->c_clustersumoff = fs32_to_cpu(sb, ucg->cg_u.cg_44.cg_clustersumoff);
66 ucpi->c_clusteroff = fs32_to_cpu(sb, ucg->cg_u.cg_44.cg_clusteroff);
67 ucpi->c_nclusterblks = fs32_to_cpu(sb, ucg->cg_u.cg_44.cg_nclusterblks);
68 UFSD("EXIT\n");
69 return;
70
71 failed:
72 for (j = 1; j < i; j++)
73 brelse (sbi->s_ucg[j]);
74 sbi->s_cgno[bitmap_nr] = UFS_CGNO_EMPTY;
75 ufs_error (sb, "ufs_read_cylinder", "can't read cylinder group block %u", cgno);
76 }
77
78 /*
79 * Remove cylinder group from cache, doesn't release memory
80 * allocated for cylinder group (this is done at ufs_put_super only).
81 */
ufs_put_cylinder(struct super_block * sb,unsigned bitmap_nr)82 void ufs_put_cylinder (struct super_block * sb, unsigned bitmap_nr)
83 {
84 struct ufs_sb_info * sbi = UFS_SB(sb);
85 struct ufs_sb_private_info * uspi;
86 struct ufs_cg_private_info * ucpi;
87 struct ufs_cylinder_group * ucg;
88 unsigned i;
89
90 UFSD("ENTER, bitmap_nr %u\n", bitmap_nr);
91
92 uspi = sbi->s_uspi;
93 if (sbi->s_cgno[bitmap_nr] == UFS_CGNO_EMPTY) {
94 UFSD("EXIT\n");
95 return;
96 }
97 ucpi = sbi->s_ucpi[bitmap_nr];
98 ucg = ubh_get_ucg(UCPI_UBH(ucpi));
99
100 if (uspi->s_ncg > UFS_MAX_GROUP_LOADED && bitmap_nr >= sbi->s_cg_loaded) {
101 ufs_panic (sb, "ufs_put_cylinder", "internal error");
102 return;
103 }
104 /*
105 * rotor is not so important data, so we put it to disk
106 * at the end of working with cylinder
107 */
108 ucg->cg_rotor = cpu_to_fs32(sb, ucpi->c_rotor);
109 ucg->cg_frotor = cpu_to_fs32(sb, ucpi->c_frotor);
110 ucg->cg_irotor = cpu_to_fs32(sb, ucpi->c_irotor);
111 ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
112 for (i = 1; i < UCPI_UBH(ucpi)->count; i++) {
113 brelse (UCPI_UBH(ucpi)->bh[i]);
114 }
115
116 sbi->s_cgno[bitmap_nr] = UFS_CGNO_EMPTY;
117 UFSD("EXIT\n");
118 }
119
120 /*
121 * Find cylinder group in cache and return it as pointer.
122 * If cylinder group is not in cache, we will load it from disk.
123 *
124 * The cache is managed by LRU algorithm.
125 */
ufs_load_cylinder(struct super_block * sb,unsigned cgno)126 struct ufs_cg_private_info * ufs_load_cylinder (
127 struct super_block * sb, unsigned cgno)
128 {
129 struct ufs_sb_info * sbi = UFS_SB(sb);
130 struct ufs_sb_private_info * uspi;
131 struct ufs_cg_private_info * ucpi;
132 unsigned cg, i, j;
133
134 UFSD("ENTER, cgno %u\n", cgno);
135
136 uspi = sbi->s_uspi;
137 if (cgno >= uspi->s_ncg) {
138 ufs_panic (sb, "ufs_load_cylinder", "internal error, high number of cg");
139 return NULL;
140 }
141 /*
142 * Cylinder group number cg it in cache and it was last used
143 */
144 if (sbi->s_cgno[0] == cgno) {
145 UFSD("EXIT\n");
146 return sbi->s_ucpi[0];
147 }
148 /*
149 * Number of cylinder groups is not higher than UFS_MAX_GROUP_LOADED
150 */
151 if (uspi->s_ncg <= UFS_MAX_GROUP_LOADED) {
152 if (sbi->s_cgno[cgno] != UFS_CGNO_EMPTY) {
153 if (sbi->s_cgno[cgno] != cgno) {
154 ufs_panic (sb, "ufs_load_cylinder", "internal error, wrong number of cg in cache");
155 UFSD("EXIT (FAILED)\n");
156 return NULL;
157 }
158 else {
159 UFSD("EXIT\n");
160 return sbi->s_ucpi[cgno];
161 }
162 } else {
163 ufs_read_cylinder (sb, cgno, cgno);
164 UFSD("EXIT\n");
165 return sbi->s_ucpi[cgno];
166 }
167 }
168 /*
169 * Cylinder group number cg is in cache but it was not last used,
170 * we will move to the first position
171 */
172 for (i = 0; i < sbi->s_cg_loaded && sbi->s_cgno[i] != cgno; i++);
173 if (i < sbi->s_cg_loaded && sbi->s_cgno[i] == cgno) {
174 cg = sbi->s_cgno[i];
175 ucpi = sbi->s_ucpi[i];
176 for (j = i; j > 0; j--) {
177 sbi->s_cgno[j] = sbi->s_cgno[j-1];
178 sbi->s_ucpi[j] = sbi->s_ucpi[j-1];
179 }
180 sbi->s_cgno[0] = cg;
181 sbi->s_ucpi[0] = ucpi;
182 /*
183 * Cylinder group number cg is not in cache, we will read it from disk
184 * and put it to the first position
185 */
186 } else {
187 if (sbi->s_cg_loaded < UFS_MAX_GROUP_LOADED)
188 sbi->s_cg_loaded++;
189 else
190 ufs_put_cylinder (sb, UFS_MAX_GROUP_LOADED-1);
191 ucpi = sbi->s_ucpi[sbi->s_cg_loaded - 1];
192 for (j = sbi->s_cg_loaded - 1; j > 0; j--) {
193 sbi->s_cgno[j] = sbi->s_cgno[j-1];
194 sbi->s_ucpi[j] = sbi->s_ucpi[j-1];
195 }
196 sbi->s_ucpi[0] = ucpi;
197 ufs_read_cylinder (sb, cgno, 0);
198 }
199 UFSD("EXIT\n");
200 return sbi->s_ucpi[0];
201 }
202