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1da177e4 LT |
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/time.h> | |
14 | #include <linux/stat.h> | |
15 | #include <linux/string.h> | |
16 | #include <linux/bitops.h> | |
17 | ||
18 | #include <asm/byteorder.h> | |
19 | ||
20 | #include "swab.h" | |
21 | #include "util.h" | |
22 | ||
23 | #undef UFS_CYLINDER_DEBUG | |
24 | ||
25 | #ifdef UFS_CYLINDER_DEBUG | |
26 | #define UFSD(x) printk("(%s, %d), %s:", __FILE__, __LINE__, __FUNCTION__); printk x; | |
27 | #else | |
28 | #define UFSD(x) | |
29 | #endif | |
30 | ||
31 | ||
32 | /* | |
33 | * Read cylinder group into cache. The memory space for ufs_cg_private_info | |
34 | * structure is already allocated during ufs_read_super. | |
35 | */ | |
36 | static void ufs_read_cylinder (struct super_block * sb, | |
37 | unsigned cgno, unsigned bitmap_nr) | |
38 | { | |
39 | struct ufs_sb_info * sbi = UFS_SB(sb); | |
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 = sbi->s_uspi; | |
47 | ucpi = sbi->s_ucpi[bitmap_nr]; | |
48 | ucg = (struct ufs_cylinder_group *)sbi->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] = sbi->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 | sbi->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 (sbi->s_ucg[j]); | |
82 | sbi->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 | */ | |
90 | void ufs_put_cylinder (struct super_block * sb, unsigned bitmap_nr) | |
91 | { | |
92 | struct ufs_sb_info * sbi = UFS_SB(sb); | |
93 | struct ufs_sb_private_info * uspi; | |
94 | struct ufs_cg_private_info * ucpi; | |
95 | struct ufs_cylinder_group * ucg; | |
96 | unsigned i; | |
97 | ||
98 | UFSD(("ENTER, bitmap_nr %u\n", bitmap_nr)) | |
99 | ||
100 | uspi = sbi->s_uspi; | |
101 | if (sbi->s_cgno[bitmap_nr] == UFS_CGNO_EMPTY) { | |
102 | UFSD(("EXIT\n")) | |
103 | return; | |
104 | } | |
105 | ucpi = sbi->s_ucpi[bitmap_nr]; | |
106 | ucg = ubh_get_ucg(UCPI_UBH); | |
107 | ||
108 | if (uspi->s_ncg > UFS_MAX_GROUP_LOADED && bitmap_nr >= sbi->s_cg_loaded) { | |
109 | ufs_panic (sb, "ufs_put_cylinder", "internal error"); | |
110 | return; | |
111 | } | |
112 | /* | |
113 | * rotor is not so important data, so we put it to disk | |
114 | * at the end of working with cylinder | |
115 | */ | |
116 | ucg->cg_rotor = cpu_to_fs32(sb, ucpi->c_rotor); | |
117 | ucg->cg_frotor = cpu_to_fs32(sb, ucpi->c_frotor); | |
118 | ucg->cg_irotor = cpu_to_fs32(sb, ucpi->c_irotor); | |
119 | ubh_mark_buffer_dirty (UCPI_UBH); | |
120 | for (i = 1; i < UCPI_UBH->count; i++) { | |
121 | brelse (UCPI_UBH->bh[i]); | |
122 | } | |
123 | ||
124 | sbi->s_cgno[bitmap_nr] = UFS_CGNO_EMPTY; | |
125 | UFSD(("EXIT\n")) | |
126 | } | |
127 | ||
128 | /* | |
129 | * Find cylinder group in cache and return it as pointer. | |
130 | * If cylinder group is not in cache, we will load it from disk. | |
131 | * | |
132 | * The cache is managed by LRU algorithm. | |
133 | */ | |
134 | struct ufs_cg_private_info * ufs_load_cylinder ( | |
135 | struct super_block * sb, unsigned cgno) | |
136 | { | |
137 | struct ufs_sb_info * sbi = UFS_SB(sb); | |
138 | struct ufs_sb_private_info * uspi; | |
139 | struct ufs_cg_private_info * ucpi; | |
140 | unsigned cg, i, j; | |
141 | ||
142 | UFSD(("ENTER, cgno %u\n", cgno)) | |
143 | ||
144 | uspi = sbi->s_uspi; | |
145 | if (cgno >= uspi->s_ncg) { | |
146 | ufs_panic (sb, "ufs_load_cylinder", "internal error, high number of cg"); | |
147 | return NULL; | |
148 | } | |
149 | /* | |
150 | * Cylinder group number cg it in cache and it was last used | |
151 | */ | |
152 | if (sbi->s_cgno[0] == cgno) { | |
153 | UFSD(("EXIT\n")) | |
154 | return sbi->s_ucpi[0]; | |
155 | } | |
156 | /* | |
157 | * Number of cylinder groups is not higher than UFS_MAX_GROUP_LOADED | |
158 | */ | |
159 | if (uspi->s_ncg <= UFS_MAX_GROUP_LOADED) { | |
160 | if (sbi->s_cgno[cgno] != UFS_CGNO_EMPTY) { | |
161 | if (sbi->s_cgno[cgno] != cgno) { | |
162 | ufs_panic (sb, "ufs_load_cylinder", "internal error, wrong number of cg in cache"); | |
163 | UFSD(("EXIT (FAILED)\n")) | |
164 | return NULL; | |
165 | } | |
166 | else { | |
167 | UFSD(("EXIT\n")) | |
168 | return sbi->s_ucpi[cgno]; | |
169 | } | |
170 | } else { | |
171 | ufs_read_cylinder (sb, cgno, cgno); | |
172 | UFSD(("EXIT\n")) | |
173 | return sbi->s_ucpi[cgno]; | |
174 | } | |
175 | } | |
176 | /* | |
177 | * Cylinder group number cg is in cache but it was not last used, | |
178 | * we will move to the first position | |
179 | */ | |
180 | for (i = 0; i < sbi->s_cg_loaded && sbi->s_cgno[i] != cgno; i++); | |
181 | if (i < sbi->s_cg_loaded && sbi->s_cgno[i] == cgno) { | |
182 | cg = sbi->s_cgno[i]; | |
183 | ucpi = sbi->s_ucpi[i]; | |
184 | for (j = i; j > 0; j--) { | |
185 | sbi->s_cgno[j] = sbi->s_cgno[j-1]; | |
186 | sbi->s_ucpi[j] = sbi->s_ucpi[j-1]; | |
187 | } | |
188 | sbi->s_cgno[0] = cg; | |
189 | sbi->s_ucpi[0] = ucpi; | |
190 | /* | |
191 | * Cylinder group number cg is not in cache, we will read it from disk | |
192 | * and put it to the first position | |
193 | */ | |
194 | } else { | |
195 | if (sbi->s_cg_loaded < UFS_MAX_GROUP_LOADED) | |
196 | sbi->s_cg_loaded++; | |
197 | else | |
198 | ufs_put_cylinder (sb, UFS_MAX_GROUP_LOADED-1); | |
199 | ucpi = sbi->s_ucpi[sbi->s_cg_loaded - 1]; | |
200 | for (j = sbi->s_cg_loaded - 1; j > 0; j--) { | |
201 | sbi->s_cgno[j] = sbi->s_cgno[j-1]; | |
202 | sbi->s_ucpi[j] = sbi->s_ucpi[j-1]; | |
203 | } | |
204 | sbi->s_ucpi[0] = ucpi; | |
205 | ufs_read_cylinder (sb, cgno, 0); | |
206 | } | |
207 | UFSD(("EXIT\n")) | |
208 | return sbi->s_ucpi[0]; | |
209 | } |