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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 | */ |
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 | */ |
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 | */ |
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 |
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