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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 */
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +04008#include <linux/sched.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +09009#include <linux/slab.h>
Mikulas Patocka275f4952013-07-04 19:04:01 +020010#include <linux/blkdev.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#include "hpfs_fn.h"
12
Mikulas Patocka275f4952013-07-04 19:04:01 +020013void hpfs_prefetch_sectors(struct super_block *s, unsigned secno, int n)
14{
15 struct buffer_head *bh;
16 struct blk_plug plug;
17
18 if (n <= 0 || unlikely(secno >= hpfs_sb(s)->sb_fs_size))
19 return;
20
21 bh = sb_find_get_block(s, secno);
22 if (bh) {
23 if (buffer_uptodate(bh)) {
24 brelse(bh);
25 return;
26 }
27 brelse(bh);
28 };
29
30 blk_start_plug(&plug);
31 while (n > 0) {
32 if (unlikely(secno >= hpfs_sb(s)->sb_fs_size))
33 break;
34 sb_breadahead(s, secno);
35 secno++;
36 n--;
37 }
38 blk_finish_plug(&plug);
39}
40
Linus Torvalds1da177e2005-04-16 15:20:36 -070041/* Map a sector into a buffer and return pointers to it and to the buffer. */
42
43void *hpfs_map_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp,
44 int ahead)
45{
46 struct buffer_head *bh;
47
Mikulas Patocka7dd29d82011-05-08 20:42:54 +020048 hpfs_lock_assert(s);
49
Mikulas Patocka275f4952013-07-04 19:04:01 +020050 hpfs_prefetch_sectors(s, secno, ahead);
51
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 cond_resched();
53
54 *bhp = bh = sb_bread(s, secno);
55 if (bh != NULL)
56 return bh->b_data;
57 else {
58 printk("HPFS: hpfs_map_sector: read error\n");
59 return NULL;
60 }
61}
62
63/* Like hpfs_map_sector but don't read anything */
64
65void *hpfs_get_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp)
66{
67 struct buffer_head *bh;
68 /*return hpfs_map_sector(s, secno, bhp, 0);*/
69
Mikulas Patocka7dd29d82011-05-08 20:42:54 +020070 hpfs_lock_assert(s);
71
Linus Torvalds1da177e2005-04-16 15:20:36 -070072 cond_resched();
73
74 if ((*bhp = bh = sb_getblk(s, secno)) != NULL) {
75 if (!buffer_uptodate(bh)) wait_on_buffer(bh);
76 set_buffer_uptodate(bh);
77 return bh->b_data;
78 } else {
79 printk("HPFS: hpfs_get_sector: getblk failed\n");
80 return NULL;
81 }
82}
83
84/* Map 4 sectors into a 4buffer and return pointers to it and to the buffer. */
85
86void *hpfs_map_4sectors(struct super_block *s, unsigned secno, struct quad_buffer_head *qbh,
87 int ahead)
88{
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 char *data;
90
Mikulas Patocka7dd29d82011-05-08 20:42:54 +020091 hpfs_lock_assert(s);
92
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 cond_resched();
94
95 if (secno & 3) {
96 printk("HPFS: hpfs_map_4sectors: unaligned read\n");
97 return NULL;
98 }
99
Mikulas Patocka275f4952013-07-04 19:04:01 +0200100 hpfs_prefetch_sectors(s, secno, 4 + ahead);
101
Mikulas Patocka1c0b8a7a2014-01-29 00:11:33 +0100102 if (!(qbh->bh[0] = sb_bread(s, secno + 0))) goto bail0;
103 if (!(qbh->bh[1] = sb_bread(s, secno + 1))) goto bail1;
104 if (!(qbh->bh[2] = sb_bread(s, secno + 2))) goto bail2;
105 if (!(qbh->bh[3] = sb_bread(s, secno + 3))) goto bail3;
106
107 if (likely(qbh->bh[1]->b_data == qbh->bh[0]->b_data + 1 * 512) &&
108 likely(qbh->bh[2]->b_data == qbh->bh[0]->b_data + 2 * 512) &&
109 likely(qbh->bh[3]->b_data == qbh->bh[0]->b_data + 3 * 512)) {
110 return qbh->data = qbh->bh[0]->b_data;
111 }
112
Panagiotis Issarisf52720c2006-09-27 01:49:39 -0700113 qbh->data = data = kmalloc(2048, GFP_NOFS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 if (!data) {
115 printk("HPFS: hpfs_map_4sectors: out of memory\n");
Mikulas Patocka1c0b8a7a2014-01-29 00:11:33 +0100116 goto bail4;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 }
118
Mikulas Patocka1c0b8a7a2014-01-29 00:11:33 +0100119 memcpy(data + 0 * 512, qbh->bh[0]->b_data, 512);
120 memcpy(data + 1 * 512, qbh->bh[1]->b_data, 512);
121 memcpy(data + 2 * 512, qbh->bh[2]->b_data, 512);
122 memcpy(data + 3 * 512, qbh->bh[3]->b_data, 512);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123
124 return data;
125
Mikulas Patocka1c0b8a7a2014-01-29 00:11:33 +0100126 bail4:
127 brelse(qbh->bh[3]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 bail3:
129 brelse(qbh->bh[2]);
130 bail2:
131 brelse(qbh->bh[1]);
132 bail1:
133 brelse(qbh->bh[0]);
134 bail0:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 return NULL;
136}
137
138/* Don't read sectors */
139
140void *hpfs_get_4sectors(struct super_block *s, unsigned secno,
141 struct quad_buffer_head *qbh)
142{
143 cond_resched();
144
Mikulas Patocka7dd29d82011-05-08 20:42:54 +0200145 hpfs_lock_assert(s);
146
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 if (secno & 3) {
148 printk("HPFS: hpfs_get_4sectors: unaligned read\n");
149 return NULL;
150 }
151
Mikulas Patocka1c0b8a7a2014-01-29 00:11:33 +0100152 if (!hpfs_get_sector(s, secno + 0, &qbh->bh[0])) goto bail0;
153 if (!hpfs_get_sector(s, secno + 1, &qbh->bh[1])) goto bail1;
154 if (!hpfs_get_sector(s, secno + 2, &qbh->bh[2])) goto bail2;
155 if (!hpfs_get_sector(s, secno + 3, &qbh->bh[3])) goto bail3;
156
157 if (likely(qbh->bh[1]->b_data == qbh->bh[0]->b_data + 1 * 512) &&
158 likely(qbh->bh[2]->b_data == qbh->bh[0]->b_data + 2 * 512) &&
159 likely(qbh->bh[3]->b_data == qbh->bh[0]->b_data + 3 * 512)) {
160 return qbh->data = qbh->bh[0]->b_data;
161 }
162
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 if (!(qbh->data = kmalloc(2048, GFP_NOFS))) {
164 printk("HPFS: hpfs_get_4sectors: out of memory\n");
Mikulas Patocka1c0b8a7a2014-01-29 00:11:33 +0100165 goto bail4;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 return qbh->data;
168
Mikulas Patocka1c0b8a7a2014-01-29 00:11:33 +0100169bail4:
170 brelse(qbh->bh[3]);
171bail3:
172 brelse(qbh->bh[2]);
173bail2:
174 brelse(qbh->bh[1]);
175bail1:
176 brelse(qbh->bh[0]);
177bail0:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 return NULL;
179}
180
181
182void hpfs_brelse4(struct quad_buffer_head *qbh)
183{
Mikulas Patocka1c0b8a7a2014-01-29 00:11:33 +0100184 if (unlikely(qbh->data != qbh->bh[0]->b_data))
185 kfree(qbh->data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 brelse(qbh->bh[0]);
Mikulas Patocka1c0b8a7a2014-01-29 00:11:33 +0100187 brelse(qbh->bh[1]);
188 brelse(qbh->bh[2]);
189 brelse(qbh->bh[3]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190}
191
192void hpfs_mark_4buffers_dirty(struct quad_buffer_head *qbh)
193{
Mikulas Patocka1c0b8a7a2014-01-29 00:11:33 +0100194 if (unlikely(qbh->data != qbh->bh[0]->b_data)) {
195 memcpy(qbh->bh[0]->b_data, qbh->data + 0 * 512, 512);
196 memcpy(qbh->bh[1]->b_data, qbh->data + 1 * 512, 512);
197 memcpy(qbh->bh[2]->b_data, qbh->data + 2 * 512, 512);
198 memcpy(qbh->bh[3]->b_data, qbh->data + 3 * 512, 512);
199 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 mark_buffer_dirty(qbh->bh[0]);
201 mark_buffer_dirty(qbh->bh[1]);
202 mark_buffer_dirty(qbh->bh[2]);
203 mark_buffer_dirty(qbh->bh[3]);
204}