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epoll: prevent creating circular epoll structures
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / bfs / inode.c
blob8f3d9fd896044ffa718b3fc569a613b310c1c3ec
1 /*
2 * fs/bfs/inode.c
3 * BFS superblock and inode operations.
4 * Copyright (C) 1999-2006 Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
5 * From fs/minix, Copyright (C) 1991, 1992 Linus Torvalds.
6 *
7 * Made endianness-clean by Andrew Stribblehill <ads@wompom.org>, 2005.
8 */
9
10 #include <linux/module.h>
11 #include <linux/mm.h>
12 #include <linux/slab.h>
13 #include <linux/init.h>
14 #include <linux/fs.h>
15 #include <linux/smp_lock.h>
16 #include <linux/buffer_head.h>
17 #include <linux/vfs.h>
18 #include <asm/uaccess.h>
19 #include "bfs.h"
20
21 MODULE_AUTHOR("Tigran Aivazian <tigran@aivazian.fsnet.co.uk>");
22 MODULE_DESCRIPTION("SCO UnixWare BFS filesystem for Linux");
23 MODULE_LICENSE("GPL");
24
25 #undef DEBUG
26
27 #ifdef DEBUG
28 #define dprintf(x...) printf(x)
29 #else
30 #define dprintf(x...)
31 #endif
32
33 static void bfs_write_super(struct super_block *s);
34 void dump_imap(const char *prefix, struct super_block *s);
35
36 struct inode *bfs_iget(struct super_block *sb, unsigned long ino)
37 {
38 struct bfs_inode *di;
39 struct inode *inode;
40 struct buffer_head *bh;
41 int block, off;
42
43 inode = iget_locked(sb, ino);
44 if (IS_ERR(inode))
45 return ERR_PTR(-ENOMEM);
46 if (!(inode->i_state & I_NEW))
47 return inode;
48
49 if ((ino < BFS_ROOT_INO) || (ino > BFS_SB(inode->i_sb)->si_lasti)) {
50 printf("Bad inode number %s:%08lx\n", inode->i_sb->s_id, ino);
51 goto error;
52 }
53
54 block = (ino - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
55 bh = sb_bread(inode->i_sb, block);
56 if (!bh) {
57 printf("Unable to read inode %s:%08lx\n", inode->i_sb->s_id,
58 ino);
59 goto error;
60 }
61
62 off = (ino - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
63 di = (struct bfs_inode *)bh->b_data + off;
64
65 inode->i_mode = 0x0000FFFF & le32_to_cpu(di->i_mode);
66 if (le32_to_cpu(di->i_vtype) == BFS_VDIR) {
67 inode->i_mode |= S_IFDIR;
68 inode->i_op = &bfs_dir_inops;
69 inode->i_fop = &bfs_dir_operations;
70 } else if (le32_to_cpu(di->i_vtype) == BFS_VREG) {
71 inode->i_mode |= S_IFREG;
72 inode->i_op = &bfs_file_inops;
73 inode->i_fop = &bfs_file_operations;
74 inode->i_mapping->a_ops = &bfs_aops;
75 }
76
77 BFS_I(inode)->i_sblock = le32_to_cpu(di->i_sblock);
78 BFS_I(inode)->i_eblock = le32_to_cpu(di->i_eblock);
79 BFS_I(inode)->i_dsk_ino = le16_to_cpu(di->i_ino);
80 inode->i_uid = le32_to_cpu(di->i_uid);
81 inode->i_gid = le32_to_cpu(di->i_gid);
82 inode->i_nlink = le32_to_cpu(di->i_nlink);
83 inode->i_size = BFS_FILESIZE(di);
84 inode->i_blocks = BFS_FILEBLOCKS(di);
85 inode->i_atime.tv_sec = le32_to_cpu(di->i_atime);
86 inode->i_mtime.tv_sec = le32_to_cpu(di->i_mtime);
87 inode->i_ctime.tv_sec = le32_to_cpu(di->i_ctime);
88 inode->i_atime.tv_nsec = 0;
89 inode->i_mtime.tv_nsec = 0;
90 inode->i_ctime.tv_nsec = 0;
91
92 brelse(bh);
93 unlock_new_inode(inode);
94 return inode;
95
96 error:
97 iget_failed(inode);
98 return ERR_PTR(-EIO);
99 }
100
101 static int bfs_write_inode(struct inode *inode, int wait)
102 {
103 struct bfs_sb_info *info = BFS_SB(inode->i_sb);
104 unsigned int ino = (u16)inode->i_ino;
105 unsigned long i_sblock;
106 struct bfs_inode *di;
107 struct buffer_head *bh;
108 int block, off;
109 int err = 0;
110
111 dprintf("ino=%08x\n", ino);
112
113 if ((ino < BFS_ROOT_INO) || (ino > BFS_SB(inode->i_sb)->si_lasti)) {
114 printf("Bad inode number %s:%08x\n", inode->i_sb->s_id, ino);
115 return -EIO;
116 }
117
118 mutex_lock(&info->bfs_lock);
119 block = (ino - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
120 bh = sb_bread(inode->i_sb, block);
121 if (!bh) {
122 printf("Unable to read inode %s:%08x\n",
123 inode->i_sb->s_id, ino);
124 mutex_unlock(&info->bfs_lock);
125 return -EIO;
126 }
127
128 off = (ino - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
129 di = (struct bfs_inode *)bh->b_data + off;
130
131 if (ino == BFS_ROOT_INO)
132 di->i_vtype = cpu_to_le32(BFS_VDIR);
133 else
134 di->i_vtype = cpu_to_le32(BFS_VREG);
135
136 di->i_ino = cpu_to_le16(ino);
137 di->i_mode = cpu_to_le32(inode->i_mode);
138 di->i_uid = cpu_to_le32(inode->i_uid);
139 di->i_gid = cpu_to_le32(inode->i_gid);
140 di->i_nlink = cpu_to_le32(inode->i_nlink);
141 di->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
142 di->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
143 di->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
144 i_sblock = BFS_I(inode)->i_sblock;
145 di->i_sblock = cpu_to_le32(i_sblock);
146 di->i_eblock = cpu_to_le32(BFS_I(inode)->i_eblock);
147 di->i_eoffset = cpu_to_le32(i_sblock * BFS_BSIZE + inode->i_size - 1);
148
149 mark_buffer_dirty(bh);
150 if (wait) {
151 sync_dirty_buffer(bh);
152 if (buffer_req(bh) && !buffer_uptodate(bh))
153 err = -EIO;
154 }
155 brelse(bh);
156 mutex_unlock(&info->bfs_lock);
157 return err;
158 }
159
160 static void bfs_delete_inode(struct inode *inode)
161 {
162 unsigned long ino = inode->i_ino;
163 struct bfs_inode *di;
164 struct buffer_head *bh;
165 int block, off;
166 struct super_block *s = inode->i_sb;
167 struct bfs_sb_info *info = BFS_SB(s);
168 struct bfs_inode_info *bi = BFS_I(inode);
169
170 dprintf("ino=%08lx\n", ino);
171
172 truncate_inode_pages(&inode->i_data, 0);
173
174 if ((ino < BFS_ROOT_INO) || (ino > info->si_lasti)) {
175 printf("invalid ino=%08lx\n", ino);
176 return;
177 }
178
179 inode->i_size = 0;
180 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
181 mutex_lock(&info->bfs_lock);
182 mark_inode_dirty(inode);
183
184 block = (ino - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
185 bh = sb_bread(s, block);
186 if (!bh) {
187 printf("Unable to read inode %s:%08lx\n",
188 inode->i_sb->s_id, ino);
189 mutex_unlock(&info->bfs_lock);
190 return;
191 }
192 off = (ino - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
193 di = (struct bfs_inode *)bh->b_data + off;
194 memset((void *)di, 0, sizeof(struct bfs_inode));
195 mark_buffer_dirty(bh);
196 brelse(bh);
197
198 if (bi->i_dsk_ino) {
199 if (bi->i_sblock)
200 info->si_freeb += bi->i_eblock + 1 - bi->i_sblock;
201 info->si_freei++;
202 clear_bit(ino, info->si_imap);
203 dump_imap("delete_inode", s);
204 }
205
206 /*
207 * If this was the last file, make the previous block
208 * "last block of the last file" even if there is no
209 * real file there, saves us 1 gap.
210 */
211 if (info->si_lf_eblk == bi->i_eblock) {
212 info->si_lf_eblk = bi->i_sblock - 1;
213 mark_buffer_dirty(info->si_sbh);
214 }
215 mutex_unlock(&info->bfs_lock);
216 clear_inode(inode);
217 }
218
219 static int bfs_sync_fs(struct super_block *sb, int wait)
220 {
221 struct bfs_sb_info *info = BFS_SB(sb);
222
223 mutex_lock(&info->bfs_lock);
224 mark_buffer_dirty(info->si_sbh);
225 sb->s_dirt = 0;
226 mutex_unlock(&info->bfs_lock);
227
228 return 0;
229 }
230
231 static void bfs_write_super(struct super_block *sb)
232 {
233 if (!(sb->s_flags & MS_RDONLY))
234 bfs_sync_fs(sb, 1);
235 else
236 sb->s_dirt = 0;
237 }
238
239 static void bfs_put_super(struct super_block *s)
240 {
241 struct bfs_sb_info *info = BFS_SB(s);
242
243 if (!info)
244 return;
245
246 lock_kernel();
247
248 if (s->s_dirt)
249 bfs_write_super(s);
250
251 brelse(info->si_sbh);
252 mutex_destroy(&info->bfs_lock);
253 kfree(info->si_imap);
254 kfree(info);
255 s->s_fs_info = NULL;
256
257 unlock_kernel();
258 }
259
260 static int bfs_statfs(struct dentry *dentry, struct kstatfs *buf)
261 {
262 struct super_block *s = dentry->d_sb;
263 struct bfs_sb_info *info = BFS_SB(s);
264 u64 id = huge_encode_dev(s->s_bdev->bd_dev);
265 buf->f_type = BFS_MAGIC;
266 buf->f_bsize = s->s_blocksize;
267 buf->f_blocks = info->si_blocks;
268 buf->f_bfree = buf->f_bavail = info->si_freeb;
269 buf->f_files = info->si_lasti + 1 - BFS_ROOT_INO;
270 buf->f_ffree = info->si_freei;
271 buf->f_fsid.val[0] = (u32)id;
272 buf->f_fsid.val[1] = (u32)(id >> 32);
273 buf->f_namelen = BFS_NAMELEN;
274 return 0;
275 }
276
277 static struct kmem_cache *bfs_inode_cachep;
278
279 static struct inode *bfs_alloc_inode(struct super_block *sb)
280 {
281 struct bfs_inode_info *bi;
282 bi = kmem_cache_alloc(bfs_inode_cachep, GFP_KERNEL);
283 if (!bi)
284 return NULL;
285 return &bi->vfs_inode;
286 }
287
288 static void bfs_destroy_inode(struct inode *inode)
289 {
290 kmem_cache_free(bfs_inode_cachep, BFS_I(inode));
291 }
292
293 static void init_once(void *foo)
294 {
295 struct bfs_inode_info *bi = foo;
296
297 inode_init_once(&bi->vfs_inode);
298 }
299
300 static int init_inodecache(void)
301 {
302 bfs_inode_cachep = kmem_cache_create("bfs_inode_cache",
303 sizeof(struct bfs_inode_info),
304 0, (SLAB_RECLAIM_ACCOUNT|
305 SLAB_MEM_SPREAD),
306 init_once);
307 if (bfs_inode_cachep == NULL)
308 return -ENOMEM;
309 return 0;
310 }
311
312 static void destroy_inodecache(void)
313 {
314 kmem_cache_destroy(bfs_inode_cachep);
315 }
316
317 static const struct super_operations bfs_sops = {
318 .alloc_inode = bfs_alloc_inode,
319 .destroy_inode = bfs_destroy_inode,
320 .write_inode = bfs_write_inode,
321 .delete_inode = bfs_delete_inode,
322 .put_super = bfs_put_super,
323 .write_super = bfs_write_super,
324 .sync_fs = bfs_sync_fs,
325 .statfs = bfs_statfs,
326 };
327
328 void dump_imap(const char *prefix, struct super_block *s)
329 {
330 #ifdef DEBUG
331 int i;
332 char *tmpbuf = (char *)get_zeroed_page(GFP_KERNEL);
333
334 if (!tmpbuf)
335 return;
336 for (i = BFS_SB(s)->si_lasti; i >= 0; i--) {
337 if (i > PAGE_SIZE - 100) break;
338 if (test_bit(i, BFS_SB(s)->si_imap))
339 strcat(tmpbuf, "1");
340 else
341 strcat(tmpbuf, "0");
342 }
343 printf("BFS-fs: %s: lasti=%08lx <%s>\n",
344 prefix, BFS_SB(s)->si_lasti, tmpbuf);
345 free_page((unsigned long)tmpbuf);
346 #endif
347 }
348
349 static int bfs_fill_super(struct super_block *s, void *data, int silent)
350 {
351 struct buffer_head *bh;
352 struct bfs_super_block *bfs_sb;
353 struct inode *inode;
354 unsigned i, imap_len;
355 struct bfs_sb_info *info;
356 int ret = -EINVAL;
357 unsigned long i_sblock, i_eblock, i_eoff, s_size;
358
359 info = kzalloc(sizeof(*info), GFP_KERNEL);
360 if (!info)
361 return -ENOMEM;
362 mutex_init(&info->bfs_lock);
363 s->s_fs_info = info;
364
365 sb_set_blocksize(s, BFS_BSIZE);
366
367 info->si_sbh = sb_bread(s, 0);
368 if (!info->si_sbh)
369 goto out;
370 bfs_sb = (struct bfs_super_block *)info->si_sbh->b_data;
371 if (le32_to_cpu(bfs_sb->s_magic) != BFS_MAGIC) {
372 if (!silent)
373 printf("No BFS filesystem on %s (magic=%08x)\n",
374 s->s_id, le32_to_cpu(bfs_sb->s_magic));
375 goto out1;
376 }
377 if (BFS_UNCLEAN(bfs_sb, s) && !silent)
378 printf("%s is unclean, continuing\n", s->s_id);
379
380 s->s_magic = BFS_MAGIC;
381
382 if (le32_to_cpu(bfs_sb->s_start) > le32_to_cpu(bfs_sb->s_end)) {
383 printf("Superblock is corrupted\n");
384 goto out1;
385 }
386
387 info->si_lasti = (le32_to_cpu(bfs_sb->s_start) - BFS_BSIZE) /
388 sizeof(struct bfs_inode)
389 + BFS_ROOT_INO - 1;
390 imap_len = (info->si_lasti / 8) + 1;
391 info->si_imap = kzalloc(imap_len, GFP_KERNEL);
392 if (!info->si_imap)
393 goto out1;
394 for (i = 0; i < BFS_ROOT_INO; i++)
395 set_bit(i, info->si_imap);
396
397 s->s_op = &bfs_sops;
398 inode = bfs_iget(s, BFS_ROOT_INO);
399 if (IS_ERR(inode)) {
400 ret = PTR_ERR(inode);
401 goto out2;
402 }
403 s->s_root = d_alloc_root(inode);
404 if (!s->s_root) {
405 iput(inode);
406 ret = -ENOMEM;
407 goto out2;
408 }
409
410 info->si_blocks = (le32_to_cpu(bfs_sb->s_end) + 1) >> BFS_BSIZE_BITS;
411 info->si_freeb = (le32_to_cpu(bfs_sb->s_end) + 1
412 - le32_to_cpu(bfs_sb->s_start)) >> BFS_BSIZE_BITS;
413 info->si_freei = 0;
414 info->si_lf_eblk = 0;
415
416 /* can we read the last block? */
417 bh = sb_bread(s, info->si_blocks - 1);
418 if (!bh) {
419 printf("Last block not available: %lu\n", info->si_blocks - 1);
420 ret = -EIO;
421 goto out3;
422 }
423 brelse(bh);
424
425 bh = NULL;
426 for (i = BFS_ROOT_INO; i <= info->si_lasti; i++) {
427 struct bfs_inode *di;
428 int block = (i - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
429 int off = (i - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
430 unsigned long eblock;
431
432 if (!off) {
433 brelse(bh);
434 bh = sb_bread(s, block);
435 }
436
437 if (!bh)
438 continue;
439
440 di = (struct bfs_inode *)bh->b_data + off;
441
442 /* test if filesystem is not corrupted */
443
444 i_eoff = le32_to_cpu(di->i_eoffset);
445 i_sblock = le32_to_cpu(di->i_sblock);
446 i_eblock = le32_to_cpu(di->i_eblock);
447 s_size = le32_to_cpu(bfs_sb->s_end);
448
449 if (i_sblock > info->si_blocks ||
450 i_eblock > info->si_blocks ||
451 i_sblock > i_eblock ||
452 i_eoff > s_size ||
453 i_sblock * BFS_BSIZE > i_eoff) {
454
455 printf("Inode 0x%08x corrupted\n", i);
456
457 brelse(bh);
458 ret = -EIO;
459 goto out3;
460 }
461
462 if (!di->i_ino) {
463 info->si_freei++;
464 continue;
465 }
466 set_bit(i, info->si_imap);
467 info->si_freeb -= BFS_FILEBLOCKS(di);
468
469 eblock = le32_to_cpu(di->i_eblock);
470 if (eblock > info->si_lf_eblk)
471 info->si_lf_eblk = eblock;
472 }
473 brelse(bh);
474 if (!(s->s_flags & MS_RDONLY)) {
475 mark_buffer_dirty(info->si_sbh);
476 s->s_dirt = 1;
477 }
478 dump_imap("read_super", s);
479 return 0;
480
481 out3:
482 dput(s->s_root);
483 s->s_root = NULL;
484 out2:
485 kfree(info->si_imap);
486 out1:
487 brelse(info->si_sbh);
488 out:
489 mutex_destroy(&info->bfs_lock);
490 kfree(info);
491 s->s_fs_info = NULL;
492 return ret;
493 }
494
495 static int bfs_get_sb(struct file_system_type *fs_type,
496 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
497 {
498 return get_sb_bdev(fs_type, flags, dev_name, data, bfs_fill_super, mnt);
499 }
500
501 static struct file_system_type bfs_fs_type = {
502 .owner = THIS_MODULE,
503 .name = "bfs",
504 .get_sb = bfs_get_sb,
505 .kill_sb = kill_block_super,
506 .fs_flags = FS_REQUIRES_DEV,
507 };
508
509 static int __init init_bfs_fs(void)
510 {
511 int err = init_inodecache();
512 if (err)
513 goto out1;
514 err = register_filesystem(&bfs_fs_type);
515 if (err)
516 goto out;
517 return 0;
518 out:
519 destroy_inodecache();
520 out1:
521 return err;
522 }
523
524 static void __exit exit_bfs_fs(void)
525 {
526 unregister_filesystem(&bfs_fs_type);
527 destroy_inodecache();
528 }
529
530 module_init(init_bfs_fs)
531 module_exit(exit_bfs_fs)
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