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*/
1 /*
2 * linux/fs/ext2/file.c
3 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 *
9 * from
10 *
11 * linux/fs/minix/file.c
12 *
13 * Copyright (C) 1991, 1992 Linus Torvalds
14 *
15 * ext2 fs regular file handling primitives
16 */
17
18 #include <asm/segment.h>
19 #include <asm/system.h>
20
21 #include <linux/errno.h>
22 #include <linux/fs.h>
23 #include <linux/ext2_fs.h>
24 #include <linux/fcntl.h>
25 #include <linux/sched.h>
26 #include <linux/stat.h>
27 #include <linux/locks.h>
28
29 #define NBUF 32
30
31 #define MIN(a,b) (((a)<(b))?(a):(b))
32 #define MAX(a,b) (((a)>(b))?(a):(b))
33
34 #include <linux/fs.h>
35 #include <linux/ext2_fs.h>
36
37 static int ext2_file_read (struct inode *, struct file *, char *, int);
38 static int ext2_file_write (struct inode *, struct file *, const char *, int);
39 static void ext2_release_file (struct inode *, struct file *);
40
41 /*
42 * We have mostly NULL's here: the current defaults are ok for
43 * the ext2 filesystem.
44 */
45 static struct file_operations ext2_file_operations = {
46 NULL, /* lseek - default */
47 ext2_file_read, /* read */
48 ext2_file_write, /* write */
49 NULL, /* readdir - bad */
50 NULL, /* select - default */
51 ext2_ioctl, /* ioctl */
52 generic_mmap, /* mmap */
53 NULL, /* no special open is needed */
54 ext2_release_file, /* release */
55 ext2_sync_file, /* fsync */
56 NULL, /* fasync */
57 NULL, /* check_media_change */
58 NULL /* revalidate */
59 };
60
61 struct inode_operations ext2_file_inode_operations = {
62 &ext2_file_operations,/* default file operations */
63 NULL, /* create */
64 NULL, /* lookup */
65 NULL, /* link */
66 NULL, /* unlink */
67 NULL, /* symlink */
68 NULL, /* mkdir */
69 NULL, /* rmdir */
70 NULL, /* mknod */
71 NULL, /* rename */
72 NULL, /* readlink */
73 NULL, /* follow_link */
74 ext2_bmap, /* bmap */
75 ext2_truncate, /* truncate */
76 ext2_permission, /* permission */
77 NULL /* smap */
78 };
79
80 static int ext2_file_read (struct inode * inode, struct file * filp,
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*/
81 char * buf, int count)
82 {
83 int read, left, chars;
84 int block, blocks, offset;
85 int bhrequest, uptodate;
86 int clusterblocks;
87 struct buffer_head ** bhb, ** bhe;
88 struct buffer_head * bhreq[NBUF];
89 struct buffer_head * buflist[NBUF];
90 struct super_block * sb;
91 unsigned int size;
92 int err;
93
94 if (!inode) {
95 printk ("ext2_file_read: inode = NULL\n");
96 return -EINVAL;
97 }
98 sb = inode->i_sb;
99 if (!S_ISREG(inode->i_mode)) {
100 ext2_warning (sb, "ext2_file_read", "mode = %07o",
101 inode->i_mode);
102 return -EINVAL;
103 }
104 offset = filp->f_pos;
105 size = inode->i_size;
106 if (offset > size)
107 left = 0;
108 else
109 left = size - offset;
110 if (left > count)
111 left = count;
112 if (left <= 0)
113 return 0;
114 read = 0;
115 block = offset >> EXT2_BLOCK_SIZE_BITS(sb);
116 offset &= (sb->s_blocksize - 1);
117 chars = sb->s_blocksize - offset;
118 size = (size + sb->s_blocksize - 1) >> EXT2_BLOCK_SIZE_BITS(sb);
119 blocks = (left + offset + sb->s_blocksize - 1) >> EXT2_BLOCK_SIZE_BITS(sb);
120 bhb = bhe = buflist;
121 if (filp->f_reada) {
122 if (blocks < read_ahead[MAJOR(inode->i_dev)] >> (EXT2_BLOCK_SIZE_BITS(sb) - 9))
123 blocks = read_ahead[MAJOR(inode->i_dev)] >> (EXT2_BLOCK_SIZE_BITS(sb) - 9);
124 if (block + blocks > size)
125 blocks = size - block;
126 }
127
128 /*
129 * We do this in a two stage process. We first try and request
130 * as many blocks as we can, then we wait for the first one to
131 * complete, and then we try and wrap up as many as are actually
132 * done. This routine is rather generic, in that it can be used
133 * in a filesystem by substituting the appropriate function in
134 * for getblk
135 *
136 * This routine is optimized to make maximum use of the various
137 * buffers and caches.
138 */
139
140 clusterblocks = 0;
141
142 do {
143 bhrequest = 0;
144 uptodate = 1;
145 while (blocks) {
146 --blocks;
147 #if 1
148 if(!clusterblocks) clusterblocks = ext2_getcluster(inode, block);
149 if(clusterblocks) clusterblocks--;
150 #endif
151
152 *bhb = ext2_getblk (inode, block++, 0, &err);
153 if (*bhb && !(*bhb)->b_uptodate) {
154 uptodate = 0;
155 bhreq[bhrequest++] = *bhb;
156 }
157
158 if (++bhb == &buflist[NBUF])
159 bhb = buflist;
160
161 /*
162 * If the block we have on hand is uptodate, go ahead
163 * and complete processing
164 */
165 if (uptodate)
166 break;
167
168 if (bhb == bhe)
169 break;
170 }
171
172 /*
173 * Now request them all
174 */
175 if (bhrequest)
176 ll_rw_block (READ, bhrequest, bhreq);
177
178 do {
179 /*
180 * Finish off all I/O that has actually completed
181 */
182 if (*bhe) {
183 wait_on_buffer (*bhe);
184 if (!(*bhe)->b_uptodate) { /* read error? */
185 brelse(*bhe);
186 if (++bhe == &buflist[NBUF])
187 bhe = buflist;
188 left = 0;
189 break;
190 }
191 }
192 left -= chars;
193 if (left < 0)
194 chars += left;
195 filp->f_pos += chars;
196 read += chars;
197 if (*bhe) {
198 memcpy_tofs (buf, offset + (*bhe)->b_data,
199 chars);
200 brelse (*bhe);
201 buf += chars;
202 } else {
203 while (chars-- > 0)
204 put_user (0, buf++);
205 }
206 offset = 0;
207 chars = sb->s_blocksize;
208 if (++bhe == &buflist[NBUF])
209 bhe = buflist;
210 } while (left > 0 && bhe != bhb && (!*bhe || !(*bhe)->b_lock));
211 } while (left > 0);
212
213 /*
214 * Release the read-ahead blocks
215 */
216 while (bhe != bhb) {
217 brelse (*bhe);
218 if (++bhe == &buflist[NBUF])
219 bhe = buflist;
220 }
221 if (!read)
222 return -EIO;
223 filp->f_reada = 1;
224 if (!IS_RDONLY(inode)) {
225 inode->i_atime = CURRENT_TIME;
226 inode->i_dirt = 1;
227 }
228 return read;
229 }
230
231 static int ext2_file_write (struct inode * inode, struct file * filp,
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232 const char * buf, int count)
233 {
234 const loff_t two_gb = 2147483647;
235 loff_t pos;
236 off_t pos2;
237 long block;
238 int offset;
239 int written, c;
240 struct buffer_head * bh, *bufferlist[NBUF];
241 struct super_block * sb;
242 int err;
243 int i,buffercount,write_error;
244
245 write_error = buffercount = 0;
246 if (!inode) {
247 printk("ext2_file_write: inode = NULL\n");
248 return -EINVAL;
249 }
250 sb = inode->i_sb;
251 if (sb->s_flags & MS_RDONLY)
252 /*
253 * This fs has been automatically remounted ro because of errors
254 */
255 return -ENOSPC;
256
257 if (!S_ISREG(inode->i_mode)) {
258 ext2_warning (sb, "ext2_file_write", "mode = %07o",
259 inode->i_mode);
260 return -EINVAL;
261 }
262 down(&inode->i_sem);
263 if (filp->f_flags & O_APPEND)
264 pos = inode->i_size;
265 else
266 pos = filp->f_pos;
267 pos2 = (off_t) pos;
268 /*
269 * If a file has been opened in synchronous mode, we have to ensure
270 * that meta-data will also be written synchronously. Thus, we
271 * set the i_osync field. This field is tested by the allocation
272 * routines.
273 */
274 if (filp->f_flags & O_SYNC)
275 inode->u.ext2_i.i_osync++;
276 block = pos2 >> EXT2_BLOCK_SIZE_BITS(sb);
277 offset = pos2 & (sb->s_blocksize - 1);
278 c = sb->s_blocksize - offset;
279 written = 0;
280 while (count > 0) {
281 if (pos > two_gb) {
282 if (!written)
283 written = -EFBIG;
284 break;
285 }
286 bh = ext2_getblk (inode, block, 1, &err);
287 if (!bh) {
288 if (!written)
289 written = err;
290 break;
291 }
292 count -= c;
293 if (count < 0)
294 c += count;
295 if (c != sb->s_blocksize && !bh->b_uptodate) {
296 ll_rw_block (READ, 1, &bh);
297 wait_on_buffer (bh);
298 if (!bh->b_uptodate) {
299 brelse (bh);
300 if (!written)
301 written = -EIO;
302 break;
303 }
304 }
305 pos2 += c;
306 pos += c;
307 written += c;
308 memcpy_fromfs (bh->b_data + offset, buf, c);
309 buf += c;
310 bh->b_uptodate = 1;
311 mark_buffer_dirty(bh, 0);
312 if (filp->f_flags & O_SYNC)
313 bufferlist[buffercount++] = bh;
314 else
315 brelse(bh);
316 if (buffercount == NBUF){
317 ll_rw_block(WRITE, buffercount, bufferlist);
318 for(i=0; i<buffercount; i++){
319 wait_on_buffer(bufferlist[i]);
320 if (!bufferlist[i]->b_uptodate)
321 write_error=1;
322 brelse(bufferlist[i]);
323 }
324 buffercount=0;
325 }
326 if(write_error)
327 break;
328 block++;
329 offset = 0;
330 c = sb->s_blocksize;
331 }
332 if ( buffercount ){
333 ll_rw_block(WRITE, buffercount, bufferlist);
334 for(i=0; i<buffercount; i++){
335 wait_on_buffer(bufferlist[i]);
336 if (!bufferlist[i]->b_uptodate)
337 write_error=1;
338 brelse(bufferlist[i]);
339 }
340 }
341 if (pos > inode->i_size)
342 inode->i_size = pos;
343 if (filp->f_flags & O_SYNC)
344 inode->u.ext2_i.i_osync--;
345 up(&inode->i_sem);
346 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
347 filp->f_pos = pos;
348 inode->i_dirt = 1;
349 return written;
350 }
351
352 /*
353 * Called when a inode is released. Note that this is different
354 * from ext2_open: open gets called at every open, but release
355 * gets called only when /all/ the files are closed.
356 */
357 static void ext2_release_file (struct inode * inode, struct file * filp)
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358 {
359 if (filp->f_mode & 2)
360 ext2_discard_prealloc (inode);
361 }
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*/