1 /*
2 * linux/fs/hpfs/buffer.c
3 *
4 * Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
5 *
6 * general buffer i/o
7 */
8 #include <linux/sched.h>
9 #include <linux/slab.h>
10 #include "hpfs_fn.h"
11
12 /* Map a sector into a buffer and return pointers to it and to the buffer. */
13
hpfs_map_sector(struct super_block * s,unsigned secno,struct buffer_head ** bhp,int ahead)14 void *hpfs_map_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp,
15 int ahead)
16 {
17 struct buffer_head *bh;
18
19 hpfs_lock_assert(s);
20
21 cond_resched();
22
23 *bhp = bh = sb_bread(s, secno);
24 if (bh != NULL)
25 return bh->b_data;
26 else {
27 printk("HPFS: hpfs_map_sector: read error\n");
28 return NULL;
29 }
30 }
31
32 /* Like hpfs_map_sector but don't read anything */
33
hpfs_get_sector(struct super_block * s,unsigned secno,struct buffer_head ** bhp)34 void *hpfs_get_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp)
35 {
36 struct buffer_head *bh;
37 /*return hpfs_map_sector(s, secno, bhp, 0);*/
38
39 hpfs_lock_assert(s);
40
41 cond_resched();
42
43 if ((*bhp = bh = sb_getblk(s, secno)) != NULL) {
44 if (!buffer_uptodate(bh)) wait_on_buffer(bh);
45 set_buffer_uptodate(bh);
46 return bh->b_data;
47 } else {
48 printk("HPFS: hpfs_get_sector: getblk failed\n");
49 return NULL;
50 }
51 }
52
53 /* Map 4 sectors into a 4buffer and return pointers to it and to the buffer. */
54
hpfs_map_4sectors(struct super_block * s,unsigned secno,struct quad_buffer_head * qbh,int ahead)55 void *hpfs_map_4sectors(struct super_block *s, unsigned secno, struct quad_buffer_head *qbh,
56 int ahead)
57 {
58 struct buffer_head *bh;
59 char *data;
60
61 hpfs_lock_assert(s);
62
63 cond_resched();
64
65 if (secno & 3) {
66 printk("HPFS: hpfs_map_4sectors: unaligned read\n");
67 return NULL;
68 }
69
70 qbh->data = data = kmalloc(2048, GFP_NOFS);
71 if (!data) {
72 printk("HPFS: hpfs_map_4sectors: out of memory\n");
73 goto bail;
74 }
75
76 qbh->bh[0] = bh = sb_bread(s, secno);
77 if (!bh)
78 goto bail0;
79 memcpy(data, bh->b_data, 512);
80
81 qbh->bh[1] = bh = sb_bread(s, secno + 1);
82 if (!bh)
83 goto bail1;
84 memcpy(data + 512, bh->b_data, 512);
85
86 qbh->bh[2] = bh = sb_bread(s, secno + 2);
87 if (!bh)
88 goto bail2;
89 memcpy(data + 2 * 512, bh->b_data, 512);
90
91 qbh->bh[3] = bh = sb_bread(s, secno + 3);
92 if (!bh)
93 goto bail3;
94 memcpy(data + 3 * 512, bh->b_data, 512);
95
96 return data;
97
98 bail3:
99 brelse(qbh->bh[2]);
100 bail2:
101 brelse(qbh->bh[1]);
102 bail1:
103 brelse(qbh->bh[0]);
104 bail0:
105 kfree(data);
106 printk("HPFS: hpfs_map_4sectors: read error\n");
107 bail:
108 return NULL;
109 }
110
111 /* Don't read sectors */
112
hpfs_get_4sectors(struct super_block * s,unsigned secno,struct quad_buffer_head * qbh)113 void *hpfs_get_4sectors(struct super_block *s, unsigned secno,
114 struct quad_buffer_head *qbh)
115 {
116 cond_resched();
117
118 hpfs_lock_assert(s);
119
120 if (secno & 3) {
121 printk("HPFS: hpfs_get_4sectors: unaligned read\n");
122 return NULL;
123 }
124
125 /*return hpfs_map_4sectors(s, secno, qbh, 0);*/
126 if (!(qbh->data = kmalloc(2048, GFP_NOFS))) {
127 printk("HPFS: hpfs_get_4sectors: out of memory\n");
128 return NULL;
129 }
130 if (!(hpfs_get_sector(s, secno, &qbh->bh[0]))) goto bail0;
131 if (!(hpfs_get_sector(s, secno + 1, &qbh->bh[1]))) goto bail1;
132 if (!(hpfs_get_sector(s, secno + 2, &qbh->bh[2]))) goto bail2;
133 if (!(hpfs_get_sector(s, secno + 3, &qbh->bh[3]))) goto bail3;
134 memcpy(qbh->data, qbh->bh[0]->b_data, 512);
135 memcpy(qbh->data + 512, qbh->bh[1]->b_data, 512);
136 memcpy(qbh->data + 2*512, qbh->bh[2]->b_data, 512);
137 memcpy(qbh->data + 3*512, qbh->bh[3]->b_data, 512);
138 return qbh->data;
139
140 bail3: brelse(qbh->bh[2]);
141 bail2: brelse(qbh->bh[1]);
142 bail1: brelse(qbh->bh[0]);
143 bail0:
144 return NULL;
145 }
146
147
hpfs_brelse4(struct quad_buffer_head * qbh)148 void hpfs_brelse4(struct quad_buffer_head *qbh)
149 {
150 brelse(qbh->bh[3]);
151 brelse(qbh->bh[2]);
152 brelse(qbh->bh[1]);
153 brelse(qbh->bh[0]);
154 kfree(qbh->data);
155 }
156
hpfs_mark_4buffers_dirty(struct quad_buffer_head * qbh)157 void hpfs_mark_4buffers_dirty(struct quad_buffer_head *qbh)
158 {
159 PRINTK(("hpfs_mark_4buffers_dirty\n"));
160 memcpy(qbh->bh[0]->b_data, qbh->data, 512);
161 memcpy(qbh->bh[1]->b_data, qbh->data + 512, 512);
162 memcpy(qbh->bh[2]->b_data, qbh->data + 2 * 512, 512);
163 memcpy(qbh->bh[3]->b_data, qbh->data + 3 * 512, 512);
164 mark_buffer_dirty(qbh->bh[0]);
165 mark_buffer_dirty(qbh->bh[1]);
166 mark_buffer_dirty(qbh->bh[2]);
167 mark_buffer_dirty(qbh->bh[3]);
168 }
169