This source file includes following definitions.
- ext_file_read
- ext_file_write
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15 #include <asm/segment.h>
16 #include <asm/system.h>
17
18 #include <linux/sched.h>
19 #include <linux/ext_fs.h>
20 #include <linux/kernel.h>
21 #include <linux/errno.h>
22 #include <linux/fcntl.h>
23 #include <linux/stat.h>
24 #include <linux/locks.h>
25
26 #define NBUF 32
27
28 #define MIN(a,b) (((a)<(b))?(a):(b))
29 #define MAX(a,b) (((a)>(b))?(a):(b))
30
31 #include <linux/fs.h>
32 #include <linux/ext_fs.h>
33
34 static int ext_file_read(struct inode *, struct file *, char *, int);
35 static int ext_file_write(struct inode *, struct file *, char *, int);
36
37
38
39
40
41 static struct file_operations ext_file_operations = {
42 NULL,
43 ext_file_read,
44 ext_file_write,
45 NULL,
46 NULL,
47 NULL,
48 generic_mmap,
49 NULL,
50 NULL,
51 ext_sync_file
52 };
53
54 struct inode_operations ext_file_inode_operations = {
55 &ext_file_operations,
56 NULL,
57 NULL,
58 NULL,
59 NULL,
60 NULL,
61 NULL,
62 NULL,
63 NULL,
64 NULL,
65 NULL,
66 NULL,
67 ext_bmap,
68 ext_truncate,
69 NULL
70 };
71
72 static int ext_file_read(struct inode * inode, struct file * filp, char * buf, int count)
73 {
74 int read,left,chars;
75 int block, blocks, offset;
76 int bhrequest, uptodate;
77 struct buffer_head ** bhb, ** bhe;
78 struct buffer_head * bhreq[NBUF];
79 struct buffer_head * buflist[NBUF];
80 unsigned int size;
81
82 if (!inode) {
83 printk("ext_file_read: inode = NULL\n");
84 return -EINVAL;
85 }
86 if (!S_ISREG(inode->i_mode)) {
87 printk("ext_file_read: mode = %07o\n",inode->i_mode);
88 return -EINVAL;
89 }
90 offset = filp->f_pos;
91 size = inode->i_size;
92 if (offset > size)
93 left = 0;
94 else
95 left = size - offset;
96 if (left > count)
97 left = count;
98 if (left <= 0)
99 return 0;
100 read = 0;
101 block = offset >> BLOCK_SIZE_BITS;
102 offset &= BLOCK_SIZE-1;
103 size = (size + (BLOCK_SIZE-1)) >> BLOCK_SIZE_BITS;
104 blocks = (left + offset + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
105 bhb = bhe = buflist;
106 if (filp->f_reada) {
107 if(blocks < read_ahead[MAJOR(inode->i_dev)] / (BLOCK_SIZE >> 9))
108 blocks = read_ahead[MAJOR(inode->i_dev)] / (BLOCK_SIZE >> 9);
109 if (block + blocks > size)
110 blocks = size - block;
111 }
112
113
114
115
116
117
118
119
120
121
122
123 do {
124 bhrequest = 0;
125 uptodate = 1;
126 while (blocks) {
127 --blocks;
128 *bhb = ext_getblk(inode, block++, 0);
129 if (*bhb && !(*bhb)->b_uptodate) {
130 uptodate = 0;
131 bhreq[bhrequest++] = *bhb;
132 }
133
134 if (++bhb == &buflist[NBUF])
135 bhb = buflist;
136
137
138
139 if (uptodate)
140 break;
141 if (bhb == bhe)
142 break;
143 }
144
145
146 if (bhrequest)
147 ll_rw_block(READ, bhrequest, bhreq);
148
149 do {
150 if (*bhe) {
151 wait_on_buffer(*bhe);
152 if (!(*bhe)->b_uptodate) {
153 brelse(*bhe);
154 if (++bhe == &buflist[NBUF])
155 bhe = buflist;
156 left = 0;
157 break;
158 }
159 }
160 if (left < BLOCK_SIZE - offset)
161 chars = left;
162 else
163 chars = BLOCK_SIZE - offset;
164 filp->f_pos += chars;
165 left -= chars;
166 read += chars;
167 if (*bhe) {
168 memcpy_tofs(buf,offset+(*bhe)->b_data,chars);
169 brelse(*bhe);
170 buf += chars;
171 } else {
172 while (chars-->0)
173 put_user(0,buf++);
174 }
175 offset = 0;
176 if (++bhe == &buflist[NBUF])
177 bhe = buflist;
178 } while (left > 0 && bhe != bhb && (!*bhe || !(*bhe)->b_lock));
179 } while (left > 0);
180
181
182 while (bhe != bhb) {
183 brelse(*bhe);
184 if (++bhe == &buflist[NBUF])
185 bhe = buflist;
186 };
187 if (!read)
188 return -EIO;
189 filp->f_reada = 1;
190 if (!IS_RDONLY(inode)) {
191 inode->i_atime = CURRENT_TIME;
192 inode->i_dirt = 1;
193 }
194 return read;
195 }
196
197 static int ext_file_write(struct inode * inode, struct file * filp, char * buf, int count)
198 {
199 off_t pos;
200 int written,c;
201 struct buffer_head * bh;
202 char * p;
203
204 if (!inode) {
205 printk("ext_file_write: inode = NULL\n");
206 return -EINVAL;
207 }
208 if (!S_ISREG(inode->i_mode)) {
209 printk("ext_file_write: mode = %07o\n",inode->i_mode);
210 return -EINVAL;
211 }
212
213
214
215
216 if (filp->f_flags & O_APPEND)
217 pos = inode->i_size;
218 else
219 pos = filp->f_pos;
220 written = 0;
221 while (written<count) {
222 bh = ext_getblk(inode,pos/BLOCK_SIZE,1);
223 if (!bh) {
224 if (!written)
225 written = -ENOSPC;
226 break;
227 }
228 c = BLOCK_SIZE - (pos % BLOCK_SIZE);
229 if (c > count-written)
230 c = count-written;
231 if (c != BLOCK_SIZE && !bh->b_uptodate) {
232 ll_rw_block(READ, 1, &bh);
233 wait_on_buffer(bh);
234 if (!bh->b_uptodate) {
235 brelse(bh);
236 if (!written)
237 written = -EIO;
238 break;
239 }
240 }
241 p = (pos % BLOCK_SIZE) + bh->b_data;
242 pos += c;
243 if (pos > inode->i_size) {
244 inode->i_size = pos;
245 inode->i_dirt = 1;
246 }
247 written += c;
248 memcpy_fromfs(p,buf,c);
249 buf += c;
250 bh->b_uptodate = 1;
251 mark_buffer_dirty(bh, 0);
252 brelse(bh);
253 }
254 inode->i_mtime = inode->i_ctime = CURRENT_TIME;
255 filp->f_pos = pos;
256 inode->i_dirt = 1;
257 return written;
258 }