1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/fs/hpfs/buffer.c
4 *
5 * Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
6 *
7 * general buffer i/o
8 */
9 #include <linux/sched.h>
10 #include <linux/slab.h>
11 #include <linux/blkdev.h>
12 #include "hpfs_fn.h"
13
14 secno hpfs_search_hotfix_map(struct super_block *s, secno sec)
15 {
16 unsigned i;
17 struct hpfs_sb_info *sbi = hpfs_sb(s);
18 for (i = 0; unlikely(i < sbi->n_hotfixes); i++) {
19 if (sbi->hotfix_from[i] == sec) {
20 return sbi->hotfix_to[i];
21 }
22 }
23 return sec;
24 }
25
26 unsigned hpfs_search_hotfix_map_for_range(struct super_block *s, secno sec, unsigned n)
27 {
28 unsigned i;
29 struct hpfs_sb_info *sbi = hpfs_sb(s);
30 for (i = 0; unlikely(i < sbi->n_hotfixes); i++) {
31 if (sbi->hotfix_from[i] >= sec && sbi->hotfix_from[i] < sec + n) {
32 n = sbi->hotfix_from[i] - sec;
33 }
34 }
35 return n;
36 }
37
38 void hpfs_prefetch_sectors(struct super_block *s, unsigned secno, int n)
39 {
40 struct buffer_head *bh;
41 struct blk_plug plug;
42
43 if (n <= 0 || unlikely(secno >= hpfs_sb(s)->sb_fs_size))
44 return;
45
46 if (unlikely(hpfs_search_hotfix_map_for_range(s, secno, n) != n))
47 return;
48
49 bh = sb_find_get_block(s, secno);
50 if (bh) {
51 if (buffer_uptodate(bh)) {
52 brelse(bh);
53 return;
54 }
55 brelse(bh);
56 }
57
58 blk_start_plug(&plug);
59 while (n > 0) {
60 if (unlikely(secno >= hpfs_sb(s)->sb_fs_size))
61 break;
62 sb_breadahead(s, secno);
63 secno++;
64 n--;
65 }
66 blk_finish_plug(&plug);
67 }
68
69 /* Map a sector into a buffer and return pointers to it and to the buffer. */
70
71 void *hpfs_map_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp,
72 int ahead)
73 {
74 struct buffer_head *bh;
75
76 hpfs_lock_assert(s);
77
78 hpfs_prefetch_sectors(s, secno, ahead);
79
80 cond_resched();
81
82 *bhp = bh = sb_bread(s, hpfs_search_hotfix_map(s, secno));
83 if (bh != NULL)
84 return bh->b_data;
85 else {
86 pr_err("%s(): read error\n", __func__);
87 return NULL;
88 }
89 }
90
91 /* Like hpfs_map_sector but don't read anything */
92
93 void *hpfs_get_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp)
94 {
95 struct buffer_head *bh;
96 /*return hpfs_map_sector(s, secno, bhp, 0);*/
97
98 hpfs_lock_assert(s);
99
100 cond_resched();
101
102 if ((*bhp = bh = sb_getblk(s, hpfs_search_hotfix_map(s, secno))) != NULL) {
103 if (!buffer_uptodate(bh)) wait_on_buffer(bh);
104 set_buffer_uptodate(bh);
105 return bh->b_data;
106 } else {
107 pr_err("%s(): getblk failed\n", __func__);
108 return NULL;
109 }
110 }
111
112 /* Map 4 sectors into a 4buffer and return pointers to it and to the buffer. */
113
114 void *hpfs_map_4sectors(struct super_block *s, unsigned secno, struct quad_buffer_head *qbh,
115 int ahead)
116 {
117 char *data;
118
119 hpfs_lock_assert(s);
120
121 cond_resched();
122
123 if (secno & 3) {
124 pr_err("%s(): unaligned read\n", __func__);
125 return NULL;
126 }
127
128 hpfs_prefetch_sectors(s, secno, 4 + ahead);
129
130 if (!hpfs_map_sector(s, secno + 0, &qbh->bh[0], 0)) goto bail0;
131 if (!hpfs_map_sector(s, secno + 1, &qbh->bh[1], 0)) goto bail1;
132 if (!hpfs_map_sector(s, secno + 2, &qbh->bh[2], 0)) goto bail2;
133 if (!hpfs_map_sector(s, secno + 3, &qbh->bh[3], 0)) goto bail3;
134
135 if (likely(qbh->bh[1]->b_data == qbh->bh[0]->b_data + 1 * 512) &&
136 likely(qbh->bh[2]->b_data == qbh->bh[0]->b_data + 2 * 512) &&
137 likely(qbh->bh[3]->b_data == qbh->bh[0]->b_data + 3 * 512)) {
138 return qbh->data = qbh->bh[0]->b_data;
139 }
140
141 qbh->data = data = kmalloc(2048, GFP_NOFS);
142 if (!data) {
143 pr_err("%s(): out of memory\n", __func__);
144 goto bail4;
145 }
146
147 memcpy(data + 0 * 512, qbh->bh[0]->b_data, 512);
148 memcpy(data + 1 * 512, qbh->bh[1]->b_data, 512);
149 memcpy(data + 2 * 512, qbh->bh[2]->b_data, 512);
150 memcpy(data + 3 * 512, qbh->bh[3]->b_data, 512);
151
152 return data;
153
154 bail4:
155 brelse(qbh->bh[3]);
156 bail3:
157 brelse(qbh->bh[2]);
158 bail2:
159 brelse(qbh->bh[1]);
160 bail1:
161 brelse(qbh->bh[0]);
162 bail0:
163 return NULL;
164 }
165
166 /* Don't read sectors */
167
168 void *hpfs_get_4sectors(struct super_block *s, unsigned secno,
169 struct quad_buffer_head *qbh)
170 {
171 cond_resched();
172
173 hpfs_lock_assert(s);
174
175 if (secno & 3) {
176 pr_err("%s(): unaligned read\n", __func__);
177 return NULL;
178 }
179
180 if (!hpfs_get_sector(s, secno + 0, &qbh->bh[0])) goto bail0;
181 if (!hpfs_get_sector(s, secno + 1, &qbh->bh[1])) goto bail1;
182 if (!hpfs_get_sector(s, secno + 2, &qbh->bh[2])) goto bail2;
183 if (!hpfs_get_sector(s, secno + 3, &qbh->bh[3])) goto bail3;
184
185 if (likely(qbh->bh[1]->b_data == qbh->bh[0]->b_data + 1 * 512) &&
186 likely(qbh->bh[2]->b_data == qbh->bh[0]->b_data + 2 * 512) &&
187 likely(qbh->bh[3]->b_data == qbh->bh[0]->b_data + 3 * 512)) {
188 return qbh->data = qbh->bh[0]->b_data;
189 }
190
191 if (!(qbh->data = kmalloc(2048, GFP_NOFS))) {
192 pr_err("%s(): out of memory\n", __func__);
193 goto bail4;
194 }
195 return qbh->data;
196
197 bail4:
198 brelse(qbh->bh[3]);
199 bail3:
200 brelse(qbh->bh[2]);
201 bail2:
202 brelse(qbh->bh[1]);
203 bail1:
204 brelse(qbh->bh[0]);
205 bail0:
206 return NULL;
207 }
208
209
210 void hpfs_brelse4(struct quad_buffer_head *qbh)
211 {
212 if (unlikely(qbh->data != qbh->bh[0]->b_data))
213 kfree(qbh->data);
214 brelse(qbh->bh[0]);
215 brelse(qbh->bh[1]);
216 brelse(qbh->bh[2]);
217 brelse(qbh->bh[3]);
218 }
219
220 void hpfs_mark_4buffers_dirty(struct quad_buffer_head *qbh)
221 {
222 if (unlikely(qbh->data != qbh->bh[0]->b_data)) {
223 memcpy(qbh->bh[0]->b_data, qbh->data + 0 * 512, 512);
224 memcpy(qbh->bh[1]->b_data, qbh->data + 1 * 512, 512);
225 memcpy(qbh->bh[2]->b_data, qbh->data + 2 * 512, 512);
226 memcpy(qbh->bh[3]->b_data, qbh->data + 3 * 512, 512);
227 }
228 mark_buffer_dirty(qbh->bh[0]);
229 mark_buffer_dirty(qbh->bh[1]);
230 mark_buffer_dirty(qbh->bh[2]);
231 mark_buffer_dirty(qbh->bh[3]);
232 }
233
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