This source file includes following definitions.
- minix_file_read
- minix_file_write
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9 #include <asm/segment.h>
10 #include <asm/system.h>
11
12 #include <linux/sched.h>
13 #include <linux/minix_fs.h>
14 #include <linux/kernel.h>
15 #include <linux/errno.h>
16 #include <linux/fcntl.h>
17 #include <linux/stat.h>
18 #include <linux/locks.h>
19
20 #define NBUF 16
21
22 #define MIN(a,b) (((a)<(b))?(a):(b))
23 #define MAX(a,b) (((a)>(b))?(a):(b))
24
25 #include <linux/fs.h>
26 #include <linux/minix_fs.h>
27
28 static int minix_file_read(struct inode *, struct file *, char *, int);
29 static int minix_file_write(struct inode *, struct file *, char *, int);
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34
35 static struct file_operations minix_file_operations = {
36 NULL,
37 minix_file_read,
38 minix_file_write,
39 NULL,
40 NULL,
41 NULL,
42 NULL,
43 NULL,
44 NULL
45 };
46
47 struct inode_operations minix_file_inode_operations = {
48 &minix_file_operations,
49 NULL,
50 NULL,
51 NULL,
52 NULL,
53 NULL,
54 NULL,
55 NULL,
56 NULL,
57 NULL,
58 NULL,
59 NULL,
60 minix_bmap,
61 minix_truncate
62 };
63
64 static int minix_file_read(struct inode * inode, struct file * filp, char * buf, int count)
65 {
66 int read,left,chars;
67 int block, blocks, offset;
68 int bhrequest, uptodate;
69 struct buffer_head ** bhb, ** bhe;
70 struct buffer_head * bhreq[NBUF];
71 struct buffer_head * buflist[NBUF];
72 unsigned int size;
73
74 if (!inode) {
75 printk("minix_file_read: inode = NULL\n");
76 return -EINVAL;
77 }
78 if (!S_ISREG(inode->i_mode)) {
79 printk("minix_file_read: mode = %07o\n",inode->i_mode);
80 return -EINVAL;
81 }
82 offset = filp->f_pos;
83 size = inode->i_size;
84 if (offset > size)
85 left = 0;
86 else
87 left = size - offset;
88 if (left > count)
89 left = count;
90 if (left <= 0)
91 return 0;
92 read = 0;
93 block = offset >> BLOCK_SIZE_BITS;
94 offset &= BLOCK_SIZE-1;
95 size = (size + (BLOCK_SIZE-1)) >> BLOCK_SIZE_BITS;
96 blocks = (left + offset + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
97 bhb = bhe = buflist;
98 if (filp->f_reada) {
99 blocks += read_ahead[MAJOR(inode->i_dev)] / (BLOCK_SIZE >> 9);
100 if (block + blocks > size)
101 blocks = size - block;
102 }
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112
113
114 do {
115 bhrequest = 0;
116 uptodate = 1;
117 while (blocks) {
118 --blocks;
119 *bhb = minix_getblk(inode, block++, 0);
120 if (*bhb && !(*bhb)->b_uptodate) {
121 uptodate = 0;
122 bhreq[bhrequest++] = *bhb;
123 }
124
125 if (++bhb == &buflist[NBUF])
126 bhb = buflist;
127
128
129
130 if (uptodate)
131 break;
132 if (bhb == bhe)
133 break;
134 }
135
136
137 if (bhrequest)
138 ll_rw_block(READ, bhrequest, bhreq);
139
140 do {
141 if (*bhe) {
142 wait_on_buffer(*bhe);
143 if (!(*bhe)->b_uptodate) {
144 left = 0;
145 break;
146 }
147 }
148 if (left < BLOCK_SIZE - offset)
149 chars = left;
150 else
151 chars = BLOCK_SIZE - offset;
152 filp->f_pos += chars;
153 left -= chars;
154 read += chars;
155 if (*bhe) {
156 memcpy_tofs(buf,offset+(*bhe)->b_data,chars);
157 brelse(*bhe);
158 buf += chars;
159 } else {
160 while (chars-->0)
161 put_fs_byte(0,buf++);
162 }
163 offset = 0;
164 if (++bhe == &buflist[NBUF])
165 bhe = buflist;
166 } while (left > 0 && bhe != bhb && (!*bhe || !(*bhe)->b_lock));
167 } while (left > 0);
168
169
170 while (bhe != bhb) {
171 brelse(*bhe);
172 if (++bhe == &buflist[NBUF])
173 bhe = buflist;
174 };
175 if (!read)
176 return -EIO;
177 filp->f_reada = 1;
178 if (!IS_RDONLY(inode)) {
179 inode->i_atime = CURRENT_TIME;
180 inode->i_dirt = 1;
181 }
182 return read;
183 }
184
185 static int minix_file_write(struct inode * inode, struct file * filp, char * buf, int count)
186 {
187 off_t pos;
188 int written,c;
189 struct buffer_head * bh;
190 char * p;
191
192 if (!inode) {
193 printk("minix_file_write: inode = NULL\n");
194 return -EINVAL;
195 }
196 if (!S_ISREG(inode->i_mode)) {
197 printk("minix_file_write: mode = %07o\n",inode->i_mode);
198 return -EINVAL;
199 }
200
201
202
203
204 if (filp->f_flags & O_APPEND)
205 pos = inode->i_size;
206 else
207 pos = filp->f_pos;
208 written = 0;
209 while (written<count) {
210 bh = minix_getblk(inode,pos/BLOCK_SIZE,1);
211 if (!bh) {
212 if (!written)
213 written = -ENOSPC;
214 break;
215 }
216 c = BLOCK_SIZE - (pos % BLOCK_SIZE);
217 if (c > count-written)
218 c = count-written;
219 if (c != BLOCK_SIZE && !bh->b_uptodate) {
220 ll_rw_block(READ, 1, &bh);
221 wait_on_buffer(bh);
222 if (!bh->b_uptodate) {
223 brelse(bh);
224 if (!written)
225 written = -EIO;
226 break;
227 }
228 }
229 p = (pos % BLOCK_SIZE) + bh->b_data;
230 pos += c;
231 if (pos > inode->i_size) {
232 inode->i_size = pos;
233 inode->i_dirt = 1;
234 }
235 written += c;
236 memcpy_fromfs(p,buf,c);
237 buf += c;
238 bh->b_uptodate = 1;
239 bh->b_dirt = 1;
240 brelse(bh);
241 }
242 inode->i_mtime = CURRENT_TIME;
243 inode->i_ctime = CURRENT_TIME;
244 filp->f_pos = pos;
245 inode->i_dirt = 1;
246 return written;
247 }