1 /*
2 * Optimized MPEG FS - inode and super operations.
3 * Copyright (C) 2006 Bob Copeland <me@bobcopeland.com>
4 * Released under GPL v2.
5 */
6 #include <linux/version.h>
7 #include <linux/module.h>
8 #include <linux/sched.h>
9 #include <linux/fs.h>
10 #include <linux/vfs.h>
11 #include <linux/parser.h>
12 #include <linux/buffer_head.h>
13 #include <linux/vmalloc.h>
14 #include <linux/crc-itu-t.h>
15 #include "omfs.h"
16
17 MODULE_AUTHOR("Bob Copeland <me@bobcopeland.com>");
18 MODULE_DESCRIPTION("OMFS (ReplayTV/Karma) Filesystem for Linux");
19 MODULE_LICENSE("GPL");
20
21 struct inode *omfs_new_inode(struct inode *dir, int mode)
22 {
23 struct inode *inode;
24 u64 new_block;
25 int err;
26 int len;
27 struct omfs_sb_info *sbi = OMFS_SB(dir->i_sb);
28
29 inode = new_inode(dir->i_sb);
30 if (!inode)
31 return ERR_PTR(-ENOMEM);
32
33 err = omfs_allocate_range(dir->i_sb, sbi->s_mirrors, sbi->s_mirrors,
34 &new_block, &len);
35 if (err)
36 goto fail;
37
38 inode->i_ino = new_block;
39 inode->i_mode = mode;
40 inode->i_uid = current_fsuid();
41 inode->i_gid = current_fsgid();
42 inode->i_mapping->a_ops = &omfs_aops;
43
44 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
45 switch (mode & S_IFMT) {
46 case S_IFDIR:
47 inode->i_op = &omfs_dir_inops;
48 inode->i_fop = &omfs_dir_operations;
49 inode->i_size = sbi->s_sys_blocksize;
50 inc_nlink(inode);
51 break;
52 case S_IFREG:
53 inode->i_op = &omfs_file_inops;
54 inode->i_fop = &omfs_file_operations;
55 inode->i_size = 0;
56 break;
57 }
58
59 insert_inode_hash(inode);
60 mark_inode_dirty(inode);
61 return inode;
62 fail:
63 make_bad_inode(inode);
64 iput(inode);
65 return ERR_PTR(err);
66 }
67
68 /*
69 * Update the header checksums for a dirty inode based on its contents.
70 * Caller is expected to hold the buffer head underlying oi and mark it
71 * dirty.
72 */
73 static void omfs_update_checksums(struct omfs_inode *oi)
74 {
75 int xor, i, ofs = 0, count;
76 u16 crc = 0;
77 unsigned char *ptr = (unsigned char *) oi;
78
79 count = be32_to_cpu(oi->i_head.h_body_size);
80 ofs = sizeof(struct omfs_header);
81
82 crc = crc_itu_t(crc, ptr + ofs, count);
83 oi->i_head.h_crc = cpu_to_be16(crc);
84
85 xor = ptr[0];
86 for (i = 1; i < OMFS_XOR_COUNT; i++)
87 xor ^= ptr[i];
88
89 oi->i_head.h_check_xor = xor;
90 }
91
92 static int omfs_write_inode(struct inode *inode, int wait)
93 {
94 struct omfs_inode *oi;
95 struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
96 struct buffer_head *bh, *bh2;
97 unsigned int block;
98 u64 ctime;
99 int i;
100 int ret = -EIO;
101 int sync_failed = 0;
102
103 /* get current inode since we may have written sibling ptrs etc. */
104 block = clus_to_blk(sbi, inode->i_ino);
105 bh = sb_bread(inode->i_sb, block);
106 if (!bh)
107 goto out;
108
109 oi = (struct omfs_inode *) bh->b_data;
110
111 oi->i_head.h_self = cpu_to_be64(inode->i_ino);
112 if (S_ISDIR(inode->i_mode))
113 oi->i_type = OMFS_DIR;
114 else if (S_ISREG(inode->i_mode))
115 oi->i_type = OMFS_FILE;
116 else {
117 printk(KERN_WARNING "omfs: unknown file type: %d\n",
118 inode->i_mode);
119 goto out_brelse;
120 }
121
122 oi->i_head.h_body_size = cpu_to_be32(sbi->s_sys_blocksize -
123 sizeof(struct omfs_header));
124 oi->i_head.h_version = 1;
125 oi->i_head.h_type = OMFS_INODE_NORMAL;
126 oi->i_head.h_magic = OMFS_IMAGIC;
127 oi->i_size = cpu_to_be64(inode->i_size);
128
129 ctime = inode->i_ctime.tv_sec * 1000LL +
130 ((inode->i_ctime.tv_nsec + 999)/1000);
131 oi->i_ctime = cpu_to_be64(ctime);
132
133 omfs_update_checksums(oi);
134
135 mark_buffer_dirty(bh);
136 if (wait) {
137 sync_dirty_buffer(bh);
138 if (buffer_req(bh) && !buffer_uptodate(bh))
139 sync_failed = 1;
140 }
141
142 /* if mirroring writes, copy to next fsblock */
143 for (i = 1; i < sbi->s_mirrors; i++) {
144 bh2 = sb_bread(inode->i_sb, block + i *
145 (sbi->s_blocksize / sbi->s_sys_blocksize));
146 if (!bh2)
147 goto out_brelse;
148
149 memcpy(bh2->b_data, bh->b_data, bh->b_size);
150 mark_buffer_dirty(bh2);
151 if (wait) {
152 sync_dirty_buffer(bh2);
153 if (buffer_req(bh2) && !buffer_uptodate(bh2))
154 sync_failed = 1;
155 }
156 brelse(bh2);
157 }
158 ret = (sync_failed) ? -EIO : 0;
159 out_brelse:
160 brelse(bh);
161 out:
162 return ret;
163 }
164
165 int omfs_sync_inode(struct inode *inode)
166 {
167 return omfs_write_inode(inode, 1);
168 }
169
170 /*
171 * called when an entry is deleted, need to clear the bits in the
172 * bitmaps.
173 */
174 static void omfs_delete_inode(struct inode *inode)
175 {
176 truncate_inode_pages(&inode->i_data, 0);
177
178 if (S_ISREG(inode->i_mode)) {
179 inode->i_size = 0;
180 omfs_shrink_inode(inode);
181 }
182
183 omfs_clear_range(inode->i_sb, inode->i_ino, 2);
184 clear_inode(inode);
185 }
186
187 struct inode *omfs_iget(struct super_block *sb, ino_t ino)
188 {
189 struct omfs_sb_info *sbi = OMFS_SB(sb);
190 struct omfs_inode *oi;
191 struct buffer_head *bh;
192 unsigned int block;
193 u64 ctime;
194 unsigned long nsecs;
195 struct inode *inode;
196
197 inode = iget_locked(sb, ino);
198 if (!inode)
199 return ERR_PTR(-ENOMEM);
200 if (!(inode->i_state & I_NEW))
201 return inode;
202
203 block = clus_to_blk(sbi, ino);
204 bh = sb_bread(inode->i_sb, block);
205 if (!bh)
206 goto iget_failed;
207
208 oi = (struct omfs_inode *)bh->b_data;
209
210 /* check self */
211 if (ino != be64_to_cpu(oi->i_head.h_self))
212 goto fail_bh;
213
214 inode->i_uid = sbi->s_uid;
215 inode->i_gid = sbi->s_gid;
216
217 ctime = be64_to_cpu(oi->i_ctime);
218 nsecs = do_div(ctime, 1000) * 1000L;
219
220 inode->i_atime.tv_sec = ctime;
221 inode->i_mtime.tv_sec = ctime;
222 inode->i_ctime.tv_sec = ctime;
223 inode->i_atime.tv_nsec = nsecs;
224 inode->i_mtime.tv_nsec = nsecs;
225 inode->i_ctime.tv_nsec = nsecs;
226
227 inode->i_mapping->a_ops = &omfs_aops;
228
229 switch (oi->i_type) {
230 case OMFS_DIR:
231 inode->i_mode = S_IFDIR | (S_IRWXUGO & ~sbi->s_dmask);
232 inode->i_op = &omfs_dir_inops;
233 inode->i_fop = &omfs_dir_operations;
234 inode->i_size = sbi->s_sys_blocksize;
235 inc_nlink(inode);
236 break;
237 case OMFS_FILE:
238 inode->i_mode = S_IFREG | (S_IRWXUGO & ~sbi->s_fmask);
239 inode->i_fop = &omfs_file_operations;
240 inode->i_size = be64_to_cpu(oi->i_size);
241 break;
242 }
243 brelse(bh);
244 unlock_new_inode(inode);
245 return inode;
246 fail_bh:
247 brelse(bh);
248 iget_failed:
249 iget_failed(inode);
250 return ERR_PTR(-EIO);
251 }
252
253 static void omfs_put_super(struct super_block *sb)
254 {
255 struct omfs_sb_info *sbi = OMFS_SB(sb);
256 kfree(sbi->s_imap);
257 kfree(sbi);
258 sb->s_fs_info = NULL;
259 }
260
261 static int omfs_statfs(struct dentry *dentry, struct kstatfs *buf)
262 {
263 struct super_block *s = dentry->d_sb;
264 struct omfs_sb_info *sbi = OMFS_SB(s);
265 u64 id = huge_encode_dev(s->s_bdev->bd_dev);
266
267 buf->f_type = OMFS_MAGIC;
268 buf->f_bsize = sbi->s_blocksize;
269 buf->f_blocks = sbi->s_num_blocks;
270 buf->f_files = sbi->s_num_blocks;
271 buf->f_namelen = OMFS_NAMELEN;
272 buf->f_fsid.val[0] = (u32)id;
273 buf->f_fsid.val[1] = (u32)(id >> 32);
274
275 buf->f_bfree = buf->f_bavail = buf->f_ffree =
276 omfs_count_free(s);
277
278 return 0;
279 }
280
281 static struct super_operations omfs_sops = {
282 .write_inode = omfs_write_inode,
283 .delete_inode = omfs_delete_inode,
284 .put_super = omfs_put_super,
285 .statfs = omfs_statfs,
286 .show_options = generic_show_options,
287 };
288
289 /*
290 * For Rio Karma, there is an on-disk free bitmap whose location is
291 * stored in the root block. For ReplayTV, there is no such free bitmap
292 * so we have to walk the tree. Both inodes and file data are allocated
293 * from the same map. This array can be big (300k) so we allocate
294 * in units of the blocksize.
295 */
296 static int omfs_get_imap(struct super_block *sb)
297 {
298 int bitmap_size;
299 int array_size;
300 int count;
301 struct omfs_sb_info *sbi = OMFS_SB(sb);
302 struct buffer_head *bh;
303 unsigned long **ptr;
304 sector_t block;
305
306 bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8);
307 array_size = DIV_ROUND_UP(bitmap_size, sb->s_blocksize);
308
309 if (sbi->s_bitmap_ino == ~0ULL)
310 goto out;
311
312 sbi->s_imap_size = array_size;
313 sbi->s_imap = kzalloc(array_size * sizeof(unsigned long *), GFP_KERNEL);
314 if (!sbi->s_imap)
315 goto nomem;
316
317 block = clus_to_blk(sbi, sbi->s_bitmap_ino);
318 ptr = sbi->s_imap;
319 for (count = bitmap_size; count > 0; count -= sb->s_blocksize) {
320 bh = sb_bread(sb, block++);
321 if (!bh)
322 goto nomem_free;
323 *ptr = kmalloc(sb->s_blocksize, GFP_KERNEL);
324 if (!*ptr) {
325 brelse(bh);
326 goto nomem_free;
327 }
328 memcpy(*ptr, bh->b_data, sb->s_blocksize);
329 if (count < sb->s_blocksize)
330 memset((void *)*ptr + count, 0xff,
331 sb->s_blocksize - count);
332 brelse(bh);
333 ptr++;
334 }
335 out:
336 return 0;
337
338 nomem_free:
339 for (count = 0; count < array_size; count++)
340 kfree(sbi->s_imap[count]);
341
342 kfree(sbi->s_imap);
343 nomem:
344 sbi->s_imap = NULL;
345 sbi->s_imap_size = 0;
346 return -ENOMEM;
347 }
348
349 enum {
350 Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask
351 };
352
353 static const match_table_t tokens = {
354 {Opt_uid, "uid=%u"},
355 {Opt_gid, "gid=%u"},
356 {Opt_umask, "umask=%o"},
357 {Opt_dmask, "dmask=%o"},
358 {Opt_fmask, "fmask=%o"},
359 };
360
361 static int parse_options(char *options, struct omfs_sb_info *sbi)
362 {
363 char *p;
364 substring_t args[MAX_OPT_ARGS];
365 int option;
366
367 if (!options)
368 return 1;
369
370 while ((p = strsep(&options, ",")) != NULL) {
371 int token;
372 if (!*p)
373 continue;
374
375 token = match_token(p, tokens, args);
376 switch (token) {
377 case Opt_uid:
378 if (match_int(&args[0], &option))
379 return 0;
380 sbi->s_uid = option;
381 break;
382 case Opt_gid:
383 if (match_int(&args[0], &option))
384 return 0;
385 sbi->s_gid = option;
386 break;
387 case Opt_umask:
388 if (match_octal(&args[0], &option))
389 return 0;
390 sbi->s_fmask = sbi->s_dmask = option;
391 break;
392 case Opt_dmask:
393 if (match_octal(&args[0], &option))
394 return 0;
395 sbi->s_dmask = option;
396 break;
397 case Opt_fmask:
398 if (match_octal(&args[0], &option))
399 return 0;
400 sbi->s_fmask = option;
401 break;
402 default:
403 return 0;
404 }
405 }
406 return 1;
407 }
408
409 static int omfs_fill_super(struct super_block *sb, void *data, int silent)
410 {
411 struct buffer_head *bh, *bh2;
412 struct omfs_super_block *omfs_sb;
413 struct omfs_root_block *omfs_rb;
414 struct omfs_sb_info *sbi;
415 struct inode *root;
416 sector_t start;
417 int ret = -EINVAL;
418
419 save_mount_options(sb, (char *) data);
420
421 sbi = kzalloc(sizeof(struct omfs_sb_info), GFP_KERNEL);
422 if (!sbi)
423 return -ENOMEM;
424
425 sb->s_fs_info = sbi;
426
427 sbi->s_uid = current_uid();
428 sbi->s_gid = current_gid();
429 sbi->s_dmask = sbi->s_fmask = current_umask();
430
431 if (!parse_options((char *) data, sbi))
432 goto end;
433
434 sb->s_maxbytes = 0xffffffff;
435
436 sb_set_blocksize(sb, 0x200);
437
438 bh = sb_bread(sb, 0);
439 if (!bh)
440 goto end;
441
442 omfs_sb = (struct omfs_super_block *)bh->b_data;
443
444 if (omfs_sb->s_magic != cpu_to_be32(OMFS_MAGIC)) {
445 if (!silent)
446 printk(KERN_ERR "omfs: Invalid superblock (%x)\n",
447 omfs_sb->s_magic);
448 goto out_brelse_bh;
449 }
450 sb->s_magic = OMFS_MAGIC;
451
452 sbi->s_num_blocks = be64_to_cpu(omfs_sb->s_num_blocks);
453 sbi->s_blocksize = be32_to_cpu(omfs_sb->s_blocksize);
454 sbi->s_mirrors = be32_to_cpu(omfs_sb->s_mirrors);
455 sbi->s_root_ino = be64_to_cpu(omfs_sb->s_root_block);
456 sbi->s_sys_blocksize = be32_to_cpu(omfs_sb->s_sys_blocksize);
457 mutex_init(&sbi->s_bitmap_lock);
458
459 if (sbi->s_sys_blocksize > PAGE_SIZE) {
460 printk(KERN_ERR "omfs: sysblock size (%d) is out of range\n",
461 sbi->s_sys_blocksize);
462 goto out_brelse_bh;
463 }
464
465 if (sbi->s_blocksize < sbi->s_sys_blocksize ||
466 sbi->s_blocksize > OMFS_MAX_BLOCK_SIZE) {
467 printk(KERN_ERR "omfs: block size (%d) is out of range\n",
468 sbi->s_blocksize);
469 goto out_brelse_bh;
470 }
471
472 /*
473 * Use sys_blocksize as the fs block since it is smaller than a
474 * page while the fs blocksize can be larger.
475 */
476 sb_set_blocksize(sb, sbi->s_sys_blocksize);
477
478 /*
479 * ...and the difference goes into a shift. sys_blocksize is always
480 * a power of two factor of blocksize.
481 */
482 sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -
483 get_bitmask_order(sbi->s_sys_blocksize);
484
485 start = clus_to_blk(sbi, be64_to_cpu(omfs_sb->s_root_block));
486 bh2 = sb_bread(sb, start);
487 if (!bh2)
488 goto out_brelse_bh;
489
490 omfs_rb = (struct omfs_root_block *)bh2->b_data;
491
492 sbi->s_bitmap_ino = be64_to_cpu(omfs_rb->r_bitmap);
493 sbi->s_clustersize = be32_to_cpu(omfs_rb->r_clustersize);
494
495 if (sbi->s_num_blocks != be64_to_cpu(omfs_rb->r_num_blocks)) {
496 printk(KERN_ERR "omfs: block count discrepancy between "
497 "super and root blocks (%llx, %llx)\n",
498 (unsigned long long)sbi->s_num_blocks,
499 (unsigned long long)be64_to_cpu(omfs_rb->r_num_blocks));
500 goto out_brelse_bh2;
501 }
502
503 ret = omfs_get_imap(sb);
504 if (ret)
505 goto out_brelse_bh2;
506
507 sb->s_op = &omfs_sops;
508
509 root = omfs_iget(sb, be64_to_cpu(omfs_rb->r_root_dir));
510 if (IS_ERR(root)) {
511 ret = PTR_ERR(root);
512 goto out_brelse_bh2;
513 }
514
515 sb->s_root = d_alloc_root(root);
516 if (!sb->s_root) {
517 iput(root);
518 goto out_brelse_bh2;
519 }
520 printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);
521
522 ret = 0;
523 out_brelse_bh2:
524 brelse(bh2);
525 out_brelse_bh:
526 brelse(bh);
527 end:
528 return ret;
529 }
530
531 static int omfs_get_sb(struct file_system_type *fs_type,
532 int flags, const char *dev_name,
533 void *data, struct vfsmount *m)
534 {
535 return get_sb_bdev(fs_type, flags, dev_name, data, omfs_fill_super, m);
536 }
537
538 static struct file_system_type omfs_fs_type = {
539 .owner = THIS_MODULE,
540 .name = "omfs",
541 .get_sb = omfs_get_sb,
542 .kill_sb = kill_block_super,
543 .fs_flags = FS_REQUIRES_DEV,
544 };
545
546 static int __init init_omfs_fs(void)
547 {
548 return register_filesystem(&omfs_fs_type);
549 }
550
551 static void __exit exit_omfs_fs(void)
552 {
553 unregister_filesystem(&omfs_fs_type);
554 }
555
556 module_init(init_omfs_fs);
557 module_exit(exit_omfs_fs);
558
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