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/ufs_fs.h>
13 #include <linux/sched.h>
14 #include <linux/stat.h>
15 #include <linux/string.h>
16 #include <linux/locks.h>
17
18 #include <asm/bitops.h>
19 #include <asm/byteorder.h>
20
21 #include "swab.h"
22 #include "util.h"
23
24 #undef UFS_CYLINDER_DEBUG
25
26 #ifdef UFS_CYLINDER_DEBUG
27 #define UFSD(x) printk("(%s, %d), %s:", __FILE__, __LINE__, __FUNCTION__); printk x;
28 #else
29 #define UFSD(x)
30 #endif
31
32
33 /*
34 * Read cylinder group into cache. The memory space for ufs_cg_private_info
35 * structure is already allocated during ufs_read_super.
36 */
ufs_read_cylinder(struct super_block * sb,unsigned cgno,unsigned bitmap_nr)37 static void ufs_read_cylinder (struct super_block * sb,
38 unsigned cgno, unsigned bitmap_nr)
39 {
40 struct ufs_sb_private_info * uspi;
41 struct ufs_cg_private_info * ucpi;
42 struct ufs_cylinder_group * ucg;
43 unsigned i, j;
44
45 UFSD(("ENTER, cgno %u, bitmap_nr %u\n", cgno, bitmap_nr))
46 uspi = sb->u.ufs_sb.s_uspi;
47 ucpi = sb->u.ufs_sb.s_ucpi[bitmap_nr];
48 ucg = (struct ufs_cylinder_group *)sb->u.ufs_sb.s_ucg[cgno]->b_data;
49
50 UCPI_UBH->fragment = ufs_cgcmin(cgno);
51 UCPI_UBH->count = uspi->s_cgsize >> sb->s_blocksize_bits;
52 /*
53 * We have already the first fragment of cylinder group block in buffer
54 */
55 UCPI_UBH->bh[0] = sb->u.ufs_sb.s_ucg[cgno];
56 for (i = 1; i < UCPI_UBH->count; i++)
57 if (!(UCPI_UBH->bh[i] = sb_bread(sb, UCPI_UBH->fragment + i)))
58 goto failed;
59 sb->u.ufs_sb.s_cgno[bitmap_nr] = cgno;
60
61 ucpi->c_cgx = fs32_to_cpu(sb, ucg->cg_cgx);
62 ucpi->c_ncyl = fs16_to_cpu(sb, ucg->cg_ncyl);
63 ucpi->c_niblk = fs16_to_cpu(sb, ucg->cg_niblk);
64 ucpi->c_ndblk = fs32_to_cpu(sb, ucg->cg_ndblk);
65 ucpi->c_rotor = fs32_to_cpu(sb, ucg->cg_rotor);
66 ucpi->c_frotor = fs32_to_cpu(sb, ucg->cg_frotor);
67 ucpi->c_irotor = fs32_to_cpu(sb, ucg->cg_irotor);
68 ucpi->c_btotoff = fs32_to_cpu(sb, ucg->cg_btotoff);
69 ucpi->c_boff = fs32_to_cpu(sb, ucg->cg_boff);
70 ucpi->c_iusedoff = fs32_to_cpu(sb, ucg->cg_iusedoff);
71 ucpi->c_freeoff = fs32_to_cpu(sb, ucg->cg_freeoff);
72 ucpi->c_nextfreeoff = fs32_to_cpu(sb, ucg->cg_nextfreeoff);
73 ucpi->c_clustersumoff = fs32_to_cpu(sb, ucg->cg_u.cg_44.cg_clustersumoff);
74 ucpi->c_clusteroff = fs32_to_cpu(sb, ucg->cg_u.cg_44.cg_clusteroff);
75 ucpi->c_nclusterblks = fs32_to_cpu(sb, ucg->cg_u.cg_44.cg_nclusterblks);
76 UFSD(("EXIT\n"))
77 return;
78
79 failed:
80 for (j = 1; j < i; j++)
81 brelse (sb->u.ufs_sb.s_ucg[j]);
82 sb->u.ufs_sb.s_cgno[bitmap_nr] = UFS_CGNO_EMPTY;
83 ufs_error (sb, "ufs_read_cylinder", "can't read cylinder group block %u", cgno);
84 }
85
86 /*
87 * Remove cylinder group from cache, doesn't release memory
88 * allocated for cylinder group (this is done at ufs_put_super only).
89 */
ufs_put_cylinder(struct super_block * sb,unsigned bitmap_nr)90 void ufs_put_cylinder (struct super_block * sb, unsigned bitmap_nr)
91 {
92 struct ufs_sb_private_info * uspi;
93 struct ufs_cg_private_info * ucpi;
94 struct ufs_cylinder_group * ucg;
95 unsigned i;
96
97 UFSD(("ENTER, bitmap_nr %u\n", bitmap_nr))
98
99 uspi = sb->u.ufs_sb.s_uspi;
100 if (sb->u.ufs_sb.s_cgno[bitmap_nr] == UFS_CGNO_EMPTY) {
101 UFSD(("EXIT\n"))
102 return;
103 }
104 ucpi = sb->u.ufs_sb.s_ucpi[bitmap_nr];
105 ucg = ubh_get_ucg(UCPI_UBH);
106
107 if (uspi->s_ncg > UFS_MAX_GROUP_LOADED && bitmap_nr >= sb->u.ufs_sb.s_cg_loaded) {
108 ufs_panic (sb, "ufs_put_cylinder", "internal error");
109 return;
110 }
111 /*
112 * rotor is not so important data, so we put it to disk
113 * at the end of working with cylinder
114 */
115 ucg->cg_rotor = cpu_to_fs32(sb, ucpi->c_rotor);
116 ucg->cg_frotor = cpu_to_fs32(sb, ucpi->c_frotor);
117 ucg->cg_irotor = cpu_to_fs32(sb, ucpi->c_irotor);
118 ubh_mark_buffer_dirty (UCPI_UBH);
119 for (i = 1; i < UCPI_UBH->count; i++) {
120 brelse (UCPI_UBH->bh[i]);
121 }
122
123 sb->u.ufs_sb.s_cgno[bitmap_nr] = UFS_CGNO_EMPTY;
124 UFSD(("EXIT\n"))
125 }
126
127 /*
128 * Find cylinder group in cache and return it as pointer.
129 * If cylinder group is not in cache, we will load it from disk.
130 *
131 * The cache is managed by LRU algorithm.
132 */
ufs_load_cylinder(struct super_block * sb,unsigned cgno)133 struct ufs_cg_private_info * ufs_load_cylinder (
134 struct super_block * sb, unsigned cgno)
135 {
136 struct ufs_sb_private_info * uspi;
137 struct ufs_cg_private_info * ucpi;
138 unsigned cg, i, j;
139
140 UFSD(("ENTER, cgno %u\n", cgno))
141
142 uspi = sb->u.ufs_sb.s_uspi;
143 if (cgno >= uspi->s_ncg) {
144 ufs_panic (sb, "ufs_load_cylinder", "internal error, high number of cg");
145 return NULL;
146 }
147 /*
148 * Cylinder group number cg it in cache and it was last used
149 */
150 if (sb->u.ufs_sb.s_cgno[0] == cgno) {
151 UFSD(("EXIT\n"))
152 return sb->u.ufs_sb.s_ucpi[0];
153 }
154 /*
155 * Number of cylinder groups is not higher than UFS_MAX_GROUP_LOADED
156 */
157 if (uspi->s_ncg <= UFS_MAX_GROUP_LOADED) {
158 if (sb->u.ufs_sb.s_cgno[cgno] != UFS_CGNO_EMPTY) {
159 if (sb->u.ufs_sb.s_cgno[cgno] != cgno) {
160 ufs_panic (sb, "ufs_load_cylinder", "internal error, wrong number of cg in cache");
161 UFSD(("EXIT (FAILED)\n"))
162 return NULL;
163 }
164 else {
165 UFSD(("EXIT\n"))
166 return sb->u.ufs_sb.s_ucpi[cgno];
167 }
168 } else {
169 ufs_read_cylinder (sb, cgno, cgno);
170 UFSD(("EXIT\n"))
171 return sb->u.ufs_sb.s_ucpi[cgno];
172 }
173 }
174 /*
175 * Cylinder group number cg is in cache but it was not last used,
176 * we will move to the first position
177 */
178 for (i = 0; i < sb->u.ufs_sb.s_cg_loaded && sb->u.ufs_sb.s_cgno[i] != cgno; i++);
179 if (i < sb->u.ufs_sb.s_cg_loaded && sb->u.ufs_sb.s_cgno[i] == cgno) {
180 cg = sb->u.ufs_sb.s_cgno[i];
181 ucpi = sb->u.ufs_sb.s_ucpi[i];
182 for (j = i; j > 0; j--) {
183 sb->u.ufs_sb.s_cgno[j] = sb->u.ufs_sb.s_cgno[j-1];
184 sb->u.ufs_sb.s_ucpi[j] = sb->u.ufs_sb.s_ucpi[j-1];
185 }
186 sb->u.ufs_sb.s_cgno[0] = cg;
187 sb->u.ufs_sb.s_ucpi[0] = ucpi;
188 /*
189 * Cylinder group number cg is not in cache, we will read it from disk
190 * and put it to the first position
191 */
192 } else {
193 if (sb->u.ufs_sb.s_cg_loaded < UFS_MAX_GROUP_LOADED)
194 sb->u.ufs_sb.s_cg_loaded++;
195 else
196 ufs_put_cylinder (sb, UFS_MAX_GROUP_LOADED-1);
197 ucpi = sb->u.ufs_sb.s_ucpi[sb->u.ufs_sb.s_cg_loaded - 1];
198 for (j = sb->u.ufs_sb.s_cg_loaded - 1; j > 0; j--) {
199 sb->u.ufs_sb.s_cgno[j] = sb->u.ufs_sb.s_cgno[j-1];
200 sb->u.ufs_sb.s_ucpi[j] = sb->u.ufs_sb.s_ucpi[j-1];
201 }
202 sb->u.ufs_sb.s_ucpi[0] = ucpi;
203 ufs_read_cylinder (sb, cgno, 0);
204 }
205 UFSD(("EXIT\n"))
206 return sb->u.ufs_sb.s_ucpi[0];
207 }
208