089839a6cc6404e46715df5543d4be0d9162c702
[linux-2.6.git] / fs / omfs / inode.c
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/module.h>
7 #include <linux/sched.h>
8 #include <linux/slab.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/writeback.h>
15 #include <linux/crc-itu-t.h>
16 #include "omfs.h"
17
18 MODULE_AUTHOR("Bob Copeland <me@bobcopeland.com>");
19 MODULE_DESCRIPTION("OMFS (ReplayTV/Karma) Filesystem for Linux");
20 MODULE_LICENSE("GPL");
21
22 struct inode *omfs_new_inode(struct inode *dir, int mode)
23 {
24         struct inode *inode;
25         u64 new_block;
26         int err;
27         int len;
28         struct omfs_sb_info *sbi = OMFS_SB(dir->i_sb);
29
30         inode = new_inode(dir->i_sb);
31         if (!inode)
32                 return ERR_PTR(-ENOMEM);
33
34         err = omfs_allocate_range(dir->i_sb, sbi->s_mirrors, sbi->s_mirrors,
35                         &new_block, &len);
36         if (err)
37                 goto fail;
38
39         inode->i_ino = new_block;
40         inode_init_owner(inode, NULL, mode);
41         inode->i_mapping->a_ops = &omfs_aops;
42
43         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
44         switch (mode & S_IFMT) {
45         case S_IFDIR:
46                 inode->i_op = &omfs_dir_inops;
47                 inode->i_fop = &omfs_dir_operations;
48                 inode->i_size = sbi->s_sys_blocksize;
49                 inc_nlink(inode);
50                 break;
51         case S_IFREG:
52                 inode->i_op = &omfs_file_inops;
53                 inode->i_fop = &omfs_file_operations;
54                 inode->i_size = 0;
55                 break;
56         }
57
58         insert_inode_hash(inode);
59         mark_inode_dirty(inode);
60         return inode;
61 fail:
62         make_bad_inode(inode);
63         iput(inode);
64         return ERR_PTR(err);
65 }
66
67 /*
68  * Update the header checksums for a dirty inode based on its contents.
69  * Caller is expected to hold the buffer head underlying oi and mark it
70  * dirty.
71  */
72 static void omfs_update_checksums(struct omfs_inode *oi)
73 {
74         int xor, i, ofs = 0, count;
75         u16 crc = 0;
76         unsigned char *ptr = (unsigned char *) oi;
77
78         count = be32_to_cpu(oi->i_head.h_body_size);
79         ofs = sizeof(struct omfs_header);
80
81         crc = crc_itu_t(crc, ptr + ofs, count);
82         oi->i_head.h_crc = cpu_to_be16(crc);
83
84         xor = ptr[0];
85         for (i = 1; i < OMFS_XOR_COUNT; i++)
86                 xor ^= ptr[i];
87
88         oi->i_head.h_check_xor = xor;
89 }
90
91 static int __omfs_write_inode(struct inode *inode, int wait)
92 {
93         struct omfs_inode *oi;
94         struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
95         struct buffer_head *bh, *bh2;
96         unsigned int block;
97         u64 ctime;
98         int i;
99         int ret = -EIO;
100         int sync_failed = 0;
101
102         /* get current inode since we may have written sibling ptrs etc. */
103         block = clus_to_blk(sbi, inode->i_ino);
104         bh = sb_bread(inode->i_sb, block);
105         if (!bh)
106                 goto out;
107
108         oi = (struct omfs_inode *) bh->b_data;
109
110         oi->i_head.h_self = cpu_to_be64(inode->i_ino);
111         if (S_ISDIR(inode->i_mode))
112                 oi->i_type = OMFS_DIR;
113         else if (S_ISREG(inode->i_mode))
114                 oi->i_type = OMFS_FILE;
115         else {
116                 printk(KERN_WARNING "omfs: unknown file type: %d\n",
117                         inode->i_mode);
118                 goto out_brelse;
119         }
120
121         oi->i_head.h_body_size = cpu_to_be32(sbi->s_sys_blocksize -
122                 sizeof(struct omfs_header));
123         oi->i_head.h_version = 1;
124         oi->i_head.h_type = OMFS_INODE_NORMAL;
125         oi->i_head.h_magic = OMFS_IMAGIC;
126         oi->i_size = cpu_to_be64(inode->i_size);
127
128         ctime = inode->i_ctime.tv_sec * 1000LL +
129                 ((inode->i_ctime.tv_nsec + 999)/1000);
130         oi->i_ctime = cpu_to_be64(ctime);
131
132         omfs_update_checksums(oi);
133
134         mark_buffer_dirty(bh);
135         if (wait) {
136                 sync_dirty_buffer(bh);
137                 if (buffer_req(bh) && !buffer_uptodate(bh))
138                         sync_failed = 1;
139         }
140
141         /* if mirroring writes, copy to next fsblock */
142         for (i = 1; i < sbi->s_mirrors; i++) {
143                 bh2 = sb_bread(inode->i_sb, block + i *
144                         (sbi->s_blocksize / sbi->s_sys_blocksize));
145                 if (!bh2)
146                         goto out_brelse;
147
148                 memcpy(bh2->b_data, bh->b_data, bh->b_size);
149                 mark_buffer_dirty(bh2);
150                 if (wait) {
151                         sync_dirty_buffer(bh2);
152                         if (buffer_req(bh2) && !buffer_uptodate(bh2))
153                                 sync_failed = 1;
154                 }
155                 brelse(bh2);
156         }
157         ret = (sync_failed) ? -EIO : 0;
158 out_brelse:
159         brelse(bh);
160 out:
161         return ret;
162 }
163
164 static int omfs_write_inode(struct inode *inode, struct writeback_control *wbc)
165 {
166         return __omfs_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
167 }
168
169 int omfs_sync_inode(struct inode *inode)
170 {
171         return __omfs_write_inode(inode, 1);
172 }
173
174 /*
175  * called when an entry is deleted, need to clear the bits in the
176  * bitmaps.
177  */
178 static void omfs_delete_inode(struct inode *inode)
179 {
180         truncate_inode_pages(&inode->i_data, 0);
181
182         if (S_ISREG(inode->i_mode)) {
183                 inode->i_size = 0;
184                 omfs_shrink_inode(inode);
185         }
186
187         omfs_clear_range(inode->i_sb, inode->i_ino, 2);
188         clear_inode(inode);
189 }
190
191 struct inode *omfs_iget(struct super_block *sb, ino_t ino)
192 {
193         struct omfs_sb_info *sbi = OMFS_SB(sb);
194         struct omfs_inode *oi;
195         struct buffer_head *bh;
196         unsigned int block;
197         u64 ctime;
198         unsigned long nsecs;
199         struct inode *inode;
200
201         inode = iget_locked(sb, ino);
202         if (!inode)
203                 return ERR_PTR(-ENOMEM);
204         if (!(inode->i_state & I_NEW))
205                 return inode;
206
207         block = clus_to_blk(sbi, ino);
208         bh = sb_bread(inode->i_sb, block);
209         if (!bh)
210                 goto iget_failed;
211
212         oi = (struct omfs_inode *)bh->b_data;
213
214         /* check self */
215         if (ino != be64_to_cpu(oi->i_head.h_self))
216                 goto fail_bh;
217
218         inode->i_uid = sbi->s_uid;
219         inode->i_gid = sbi->s_gid;
220
221         ctime = be64_to_cpu(oi->i_ctime);
222         nsecs = do_div(ctime, 1000) * 1000L;
223
224         inode->i_atime.tv_sec = ctime;
225         inode->i_mtime.tv_sec = ctime;
226         inode->i_ctime.tv_sec = ctime;
227         inode->i_atime.tv_nsec = nsecs;
228         inode->i_mtime.tv_nsec = nsecs;
229         inode->i_ctime.tv_nsec = nsecs;
230
231         inode->i_mapping->a_ops = &omfs_aops;
232
233         switch (oi->i_type) {
234         case OMFS_DIR:
235                 inode->i_mode = S_IFDIR | (S_IRWXUGO & ~sbi->s_dmask);
236                 inode->i_op = &omfs_dir_inops;
237                 inode->i_fop = &omfs_dir_operations;
238                 inode->i_size = sbi->s_sys_blocksize;
239                 inc_nlink(inode);
240                 break;
241         case OMFS_FILE:
242                 inode->i_mode = S_IFREG | (S_IRWXUGO & ~sbi->s_fmask);
243                 inode->i_fop = &omfs_file_operations;
244                 inode->i_size = be64_to_cpu(oi->i_size);
245                 break;
246         }
247         brelse(bh);
248         unlock_new_inode(inode);
249         return inode;
250 fail_bh:
251         brelse(bh);
252 iget_failed:
253         iget_failed(inode);
254         return ERR_PTR(-EIO);
255 }
256
257 static void omfs_put_super(struct super_block *sb)
258 {
259         struct omfs_sb_info *sbi = OMFS_SB(sb);
260         kfree(sbi->s_imap);
261         kfree(sbi);
262         sb->s_fs_info = NULL;
263 }
264
265 static int omfs_statfs(struct dentry *dentry, struct kstatfs *buf)
266 {
267         struct super_block *s = dentry->d_sb;
268         struct omfs_sb_info *sbi = OMFS_SB(s);
269         u64 id = huge_encode_dev(s->s_bdev->bd_dev);
270
271         buf->f_type = OMFS_MAGIC;
272         buf->f_bsize = sbi->s_blocksize;
273         buf->f_blocks = sbi->s_num_blocks;
274         buf->f_files = sbi->s_num_blocks;
275         buf->f_namelen = OMFS_NAMELEN;
276         buf->f_fsid.val[0] = (u32)id;
277         buf->f_fsid.val[1] = (u32)(id >> 32);
278
279         buf->f_bfree = buf->f_bavail = buf->f_ffree =
280                 omfs_count_free(s);
281
282         return 0;
283 }
284
285 static const struct super_operations omfs_sops = {
286         .write_inode    = omfs_write_inode,
287         .delete_inode   = omfs_delete_inode,
288         .put_super      = omfs_put_super,
289         .statfs         = omfs_statfs,
290         .show_options   = generic_show_options,
291 };
292
293 /*
294  * For Rio Karma, there is an on-disk free bitmap whose location is
295  * stored in the root block.  For ReplayTV, there is no such free bitmap
296  * so we have to walk the tree.  Both inodes and file data are allocated
297  * from the same map.  This array can be big (300k) so we allocate
298  * in units of the blocksize.
299  */
300 static int omfs_get_imap(struct super_block *sb)
301 {
302         int bitmap_size;
303         int array_size;
304         int count;
305         struct omfs_sb_info *sbi = OMFS_SB(sb);
306         struct buffer_head *bh;
307         unsigned long **ptr;
308         sector_t block;
309
310         bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8);
311         array_size = DIV_ROUND_UP(bitmap_size, sb->s_blocksize);
312
313         if (sbi->s_bitmap_ino == ~0ULL)
314                 goto out;
315
316         sbi->s_imap_size = array_size;
317         sbi->s_imap = kzalloc(array_size * sizeof(unsigned long *), GFP_KERNEL);
318         if (!sbi->s_imap)
319                 goto nomem;
320
321         block = clus_to_blk(sbi, sbi->s_bitmap_ino);
322         ptr = sbi->s_imap;
323         for (count = bitmap_size; count > 0; count -= sb->s_blocksize) {
324                 bh = sb_bread(sb, block++);
325                 if (!bh)
326                         goto nomem_free;
327                 *ptr = kmalloc(sb->s_blocksize, GFP_KERNEL);
328                 if (!*ptr) {
329                         brelse(bh);
330                         goto nomem_free;
331                 }
332                 memcpy(*ptr, bh->b_data, sb->s_blocksize);
333                 if (count < sb->s_blocksize)
334                         memset((void *)*ptr + count, 0xff,
335                                 sb->s_blocksize - count);
336                 brelse(bh);
337                 ptr++;
338         }
339 out:
340         return 0;
341
342 nomem_free:
343         for (count = 0; count < array_size; count++)
344                 kfree(sbi->s_imap[count]);
345
346         kfree(sbi->s_imap);
347 nomem:
348         sbi->s_imap = NULL;
349         sbi->s_imap_size = 0;
350         return -ENOMEM;
351 }
352
353 enum {
354         Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask
355 };
356
357 static const match_table_t tokens = {
358         {Opt_uid, "uid=%u"},
359         {Opt_gid, "gid=%u"},
360         {Opt_umask, "umask=%o"},
361         {Opt_dmask, "dmask=%o"},
362         {Opt_fmask, "fmask=%o"},
363 };
364
365 static int parse_options(char *options, struct omfs_sb_info *sbi)
366 {
367         char *p;
368         substring_t args[MAX_OPT_ARGS];
369         int option;
370
371         if (!options)
372                 return 1;
373
374         while ((p = strsep(&options, ",")) != NULL) {
375                 int token;
376                 if (!*p)
377                         continue;
378
379                 token = match_token(p, tokens, args);
380                 switch (token) {
381                 case Opt_uid:
382                         if (match_int(&args[0], &option))
383                                 return 0;
384                         sbi->s_uid = option;
385                         break;
386                 case Opt_gid:
387                         if (match_int(&args[0], &option))
388                                 return 0;
389                         sbi->s_gid = option;
390                         break;
391                 case Opt_umask:
392                         if (match_octal(&args[0], &option))
393                                 return 0;
394                         sbi->s_fmask = sbi->s_dmask = option;
395                         break;
396                 case Opt_dmask:
397                         if (match_octal(&args[0], &option))
398                                 return 0;
399                         sbi->s_dmask = option;
400                         break;
401                 case Opt_fmask:
402                         if (match_octal(&args[0], &option))
403                                 return 0;
404                         sbi->s_fmask = option;
405                         break;
406                 default:
407                         return 0;
408                 }
409         }
410         return 1;
411 }
412
413 static int omfs_fill_super(struct super_block *sb, void *data, int silent)
414 {
415         struct buffer_head *bh, *bh2;
416         struct omfs_super_block *omfs_sb;
417         struct omfs_root_block *omfs_rb;
418         struct omfs_sb_info *sbi;
419         struct inode *root;
420         sector_t start;
421         int ret = -EINVAL;
422
423         save_mount_options(sb, (char *) data);
424
425         sbi = kzalloc(sizeof(struct omfs_sb_info), GFP_KERNEL);
426         if (!sbi)
427                 return -ENOMEM;
428
429         sb->s_fs_info = sbi;
430
431         sbi->s_uid = current_uid();
432         sbi->s_gid = current_gid();
433         sbi->s_dmask = sbi->s_fmask = current_umask();
434
435         if (!parse_options((char *) data, sbi))
436                 goto end;
437
438         sb->s_maxbytes = 0xffffffff;
439
440         sb_set_blocksize(sb, 0x200);
441
442         bh = sb_bread(sb, 0);
443         if (!bh)
444                 goto end;
445
446         omfs_sb = (struct omfs_super_block *)bh->b_data;
447
448         if (omfs_sb->s_magic != cpu_to_be32(OMFS_MAGIC)) {
449                 if (!silent)
450                         printk(KERN_ERR "omfs: Invalid superblock (%x)\n",
451                                    omfs_sb->s_magic);
452                 goto out_brelse_bh;
453         }
454         sb->s_magic = OMFS_MAGIC;
455
456         sbi->s_num_blocks = be64_to_cpu(omfs_sb->s_num_blocks);
457         sbi->s_blocksize = be32_to_cpu(omfs_sb->s_blocksize);
458         sbi->s_mirrors = be32_to_cpu(omfs_sb->s_mirrors);
459         sbi->s_root_ino = be64_to_cpu(omfs_sb->s_root_block);
460         sbi->s_sys_blocksize = be32_to_cpu(omfs_sb->s_sys_blocksize);
461         mutex_init(&sbi->s_bitmap_lock);
462
463         if (sbi->s_sys_blocksize > PAGE_SIZE) {
464                 printk(KERN_ERR "omfs: sysblock size (%d) is out of range\n",
465                         sbi->s_sys_blocksize);
466                 goto out_brelse_bh;
467         }
468
469         if (sbi->s_blocksize < sbi->s_sys_blocksize ||
470             sbi->s_blocksize > OMFS_MAX_BLOCK_SIZE) {
471                 printk(KERN_ERR "omfs: block size (%d) is out of range\n",
472                         sbi->s_blocksize);
473                 goto out_brelse_bh;
474         }
475
476         /*
477          * Use sys_blocksize as the fs block since it is smaller than a
478          * page while the fs blocksize can be larger.
479          */
480         sb_set_blocksize(sb, sbi->s_sys_blocksize);
481
482         /*
483          * ...and the difference goes into a shift.  sys_blocksize is always
484          * a power of two factor of blocksize.
485          */
486         sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -
487                 get_bitmask_order(sbi->s_sys_blocksize);
488
489         start = clus_to_blk(sbi, be64_to_cpu(omfs_sb->s_root_block));
490         bh2 = sb_bread(sb, start);
491         if (!bh2)
492                 goto out_brelse_bh;
493
494         omfs_rb = (struct omfs_root_block *)bh2->b_data;
495
496         sbi->s_bitmap_ino = be64_to_cpu(omfs_rb->r_bitmap);
497         sbi->s_clustersize = be32_to_cpu(omfs_rb->r_clustersize);
498
499         if (sbi->s_num_blocks != be64_to_cpu(omfs_rb->r_num_blocks)) {
500                 printk(KERN_ERR "omfs: block count discrepancy between "
501                         "super and root blocks (%llx, %llx)\n",
502                         (unsigned long long)sbi->s_num_blocks,
503                         (unsigned long long)be64_to_cpu(omfs_rb->r_num_blocks));
504                 goto out_brelse_bh2;
505         }
506
507         ret = omfs_get_imap(sb);
508         if (ret)
509                 goto out_brelse_bh2;
510
511         sb->s_op = &omfs_sops;
512
513         root = omfs_iget(sb, be64_to_cpu(omfs_rb->r_root_dir));
514         if (IS_ERR(root)) {
515                 ret = PTR_ERR(root);
516                 goto out_brelse_bh2;
517         }
518
519         sb->s_root = d_alloc_root(root);
520         if (!sb->s_root) {
521                 iput(root);
522                 goto out_brelse_bh2;
523         }
524         printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);
525
526         ret = 0;
527 out_brelse_bh2:
528         brelse(bh2);
529 out_brelse_bh:
530         brelse(bh);
531 end:
532         return ret;
533 }
534
535 static int omfs_get_sb(struct file_system_type *fs_type,
536                         int flags, const char *dev_name,
537                         void *data, struct vfsmount *m)
538 {
539         return get_sb_bdev(fs_type, flags, dev_name, data, omfs_fill_super, m);
540 }
541
542 static struct file_system_type omfs_fs_type = {
543         .owner = THIS_MODULE,
544         .name = "omfs",
545         .get_sb = omfs_get_sb,
546         .kill_sb = kill_block_super,
547         .fs_flags = FS_REQUIRES_DEV,
548 };
549
550 static int __init init_omfs_fs(void)
551 {
552         return register_filesystem(&omfs_fs_type);
553 }
554
555 static void __exit exit_omfs_fs(void)
556 {
557         unregister_filesystem(&omfs_fs_type);
558 }
559
560 module_init(init_omfs_fs);
561 module_exit(exit_omfs_fs);