xref: /openbmc/linux/fs/affs/amigaffs.c (revision 64c70b1c) 
1 /*
2  *  linux/fs/affs/amigaffs.c
3  *
4  *  (c) 1996  Hans-Joachim Widmaier - Rewritten
5  *
6  *  (C) 1993  Ray Burr - Amiga FFS filesystem.
7  *
8  *  Please send bug reports to: hjw@zvw.de
9  */
10 
11 #include "affs.h"
12 
13 extern struct timezone sys_tz;
14 
15 static char ErrorBuffer[256];
16 
17 /*
18  * Functions for accessing Amiga-FFS structures.
19  */
20 
21 
22 /* Insert a header block bh into the directory dir
23  * caller must hold AFFS_DIR->i_hash_lock!
24  */
25 
26 int
27 affs_insert_hash(struct inode *dir, struct buffer_head *bh)
28 {
29 	struct super_block *sb = dir->i_sb;
30 	struct buffer_head *dir_bh;
31 	u32 ino, hash_ino;
32 	int offset;
33 
34 	ino = bh->b_blocknr;
35 	offset = affs_hash_name(sb, AFFS_TAIL(sb, bh)->name + 1, AFFS_TAIL(sb, bh)->name[0]);
36 
37 	pr_debug("AFFS: insert_hash(dir=%u, ino=%d)\n", (u32)dir->i_ino, ino);
38 
39 	dir_bh = affs_bread(sb, dir->i_ino);
40 	if (!dir_bh)
41 		return -EIO;
42 
43 	hash_ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[offset]);
44 	while (hash_ino) {
45 		affs_brelse(dir_bh);
46 		dir_bh = affs_bread(sb, hash_ino);
47 		if (!dir_bh)
48 			return -EIO;
49 		hash_ino = be32_to_cpu(AFFS_TAIL(sb, dir_bh)->hash_chain);
50 	}
51 	AFFS_TAIL(sb, bh)->parent = cpu_to_be32(dir->i_ino);
52 	AFFS_TAIL(sb, bh)->hash_chain = 0;
53 	affs_fix_checksum(sb, bh);
54 
55 	if (dir->i_ino == dir_bh->b_blocknr)
56 		AFFS_HEAD(dir_bh)->table[offset] = cpu_to_be32(ino);
57 	else
58 		AFFS_TAIL(sb, dir_bh)->hash_chain = cpu_to_be32(ino);
59 
60 	affs_adjust_checksum(dir_bh, ino);
61 	mark_buffer_dirty_inode(dir_bh, dir);
62 	affs_brelse(dir_bh);
63 
64 	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
65 	dir->i_version++;
66 	mark_inode_dirty(dir);
67 
68 	return 0;
69 }
70 
71 /* Remove a header block from its directory.
72  * caller must hold AFFS_DIR->i_hash_lock!
73  */
74 
75 int
76 affs_remove_hash(struct inode *dir, struct buffer_head *rem_bh)
77 {
78 	struct super_block *sb;
79 	struct buffer_head *bh;
80 	u32 rem_ino, hash_ino;
81 	__be32 ino;
82 	int offset, retval;
83 
84 	sb = dir->i_sb;
85 	rem_ino = rem_bh->b_blocknr;
86 	offset = affs_hash_name(sb, AFFS_TAIL(sb, rem_bh)->name+1, AFFS_TAIL(sb, rem_bh)->name[0]);
87 	pr_debug("AFFS: remove_hash(dir=%d, ino=%d, hashval=%d)\n", (u32)dir->i_ino, rem_ino, offset);
88 
89 	bh = affs_bread(sb, dir->i_ino);
90 	if (!bh)
91 		return -EIO;
92 
93 	retval = -ENOENT;
94 	hash_ino = be32_to_cpu(AFFS_HEAD(bh)->table[offset]);
95 	while (hash_ino) {
96 		if (hash_ino == rem_ino) {
97 			ino = AFFS_TAIL(sb, rem_bh)->hash_chain;
98 			if (dir->i_ino == bh->b_blocknr)
99 				AFFS_HEAD(bh)->table[offset] = ino;
100 			else
101 				AFFS_TAIL(sb, bh)->hash_chain = ino;
102 			affs_adjust_checksum(bh, be32_to_cpu(ino) - hash_ino);
103 			mark_buffer_dirty_inode(bh, dir);
104 			AFFS_TAIL(sb, rem_bh)->parent = 0;
105 			retval = 0;
106 			break;
107 		}
108 		affs_brelse(bh);
109 		bh = affs_bread(sb, hash_ino);
110 		if (!bh)
111 			return -EIO;
112 		hash_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
113 	}
114 
115 	affs_brelse(bh);
116 
117 	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
118 	dir->i_version++;
119 	mark_inode_dirty(dir);
120 
121 	return retval;
122 }
123 
124 static void
125 affs_fix_dcache(struct dentry *dentry, u32 entry_ino)
126 {
127 	struct inode *inode = dentry->d_inode;
128 	void *data = dentry->d_fsdata;
129 	struct list_head *head, *next;
130 
131 	spin_lock(&dcache_lock);
132 	head = &inode->i_dentry;
133 	next = head->next;
134 	while (next != head) {
135 		dentry = list_entry(next, struct dentry, d_alias);
136 		if (entry_ino == (u32)(long)dentry->d_fsdata) {
137 			dentry->d_fsdata = data;
138 			break;
139 		}
140 		next = next->next;
141 	}
142 	spin_unlock(&dcache_lock);
143 }
144 
145 
146 /* Remove header from link chain */
147 
148 static int
149 affs_remove_link(struct dentry *dentry)
150 {
151 	struct inode *dir, *inode = dentry->d_inode;
152 	struct super_block *sb = inode->i_sb;
153 	struct buffer_head *bh = NULL, *link_bh = NULL;
154 	u32 link_ino, ino;
155 	int retval;
156 
157 	pr_debug("AFFS: remove_link(key=%ld)\n", inode->i_ino);
158 	retval = -EIO;
159 	bh = affs_bread(sb, inode->i_ino);
160 	if (!bh)
161 		goto done;
162 
163 	link_ino = (u32)(long)dentry->d_fsdata;
164 	if (inode->i_ino == link_ino) {
165 		/* we can't remove the head of the link, as its blocknr is still used as ino,
166 		 * so we remove the block of the first link instead.
167 		 */
168 		link_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain);
169 		link_bh = affs_bread(sb, link_ino);
170 		if (!link_bh)
171 			goto done;
172 
173 		dir = iget(sb, be32_to_cpu(AFFS_TAIL(sb, link_bh)->parent));
174 		if (!dir)
175 			goto done;
176 
177 		affs_lock_dir(dir);
178 		affs_fix_dcache(dentry, link_ino);
179 		retval = affs_remove_hash(dir, link_bh);
180 		if (retval)
181 			goto done;
182 		mark_buffer_dirty_inode(link_bh, inode);
183 
184 		memcpy(AFFS_TAIL(sb, bh)->name, AFFS_TAIL(sb, link_bh)->name, 32);
185 		retval = affs_insert_hash(dir, bh);
186 		if (retval)
187 			goto done;
188 		mark_buffer_dirty_inode(bh, inode);
189 
190 		affs_unlock_dir(dir);
191 		iput(dir);
192 	} else {
193 		link_bh = affs_bread(sb, link_ino);
194 		if (!link_bh)
195 			goto done;
196 	}
197 
198 	while ((ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain)) != 0) {
199 		if (ino == link_ino) {
200 			__be32 ino2 = AFFS_TAIL(sb, link_bh)->link_chain;
201 			AFFS_TAIL(sb, bh)->link_chain = ino2;
202 			affs_adjust_checksum(bh, be32_to_cpu(ino2) - link_ino);
203 			mark_buffer_dirty_inode(bh, inode);
204 			retval = 0;
205 			/* Fix the link count, if bh is a normal header block without links */
206 			switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
207 			case ST_LINKDIR:
208 			case ST_LINKFILE:
209 				break;
210 			default:
211 				if (!AFFS_TAIL(sb, bh)->link_chain)
212 					inode->i_nlink = 1;
213 			}
214 			affs_free_block(sb, link_ino);
215 			goto done;
216 		}
217 		affs_brelse(bh);
218 		bh = affs_bread(sb, ino);
219 		if (!bh)
220 			goto done;
221 	}
222 	retval = -ENOENT;
223 done:
224 	affs_brelse(link_bh);
225 	affs_brelse(bh);
226 	return retval;
227 }
228 
229 
230 static int
231 affs_empty_dir(struct inode *inode)
232 {
233 	struct super_block *sb = inode->i_sb;
234 	struct buffer_head *bh;
235 	int retval, size;
236 
237 	retval = -EIO;
238 	bh = affs_bread(sb, inode->i_ino);
239 	if (!bh)
240 		goto done;
241 
242 	retval = -ENOTEMPTY;
243 	for (size = AFFS_SB(sb)->s_hashsize - 1; size >= 0; size--)
244 		if (AFFS_HEAD(bh)->table[size])
245 			goto not_empty;
246 	retval = 0;
247 not_empty:
248 	affs_brelse(bh);
249 done:
250 	return retval;
251 }
252 
253 
254 /* Remove a filesystem object. If the object to be removed has
255  * links to it, one of the links must be changed to inherit
256  * the file or directory. As above, any inode will do.
257  * The buffer will not be freed. If the header is a link, the
258  * block will be marked as free.
259  * This function returns a negative error number in case of
260  * an error, else 0 if the inode is to be deleted or 1 if not.
261  */
262 
263 int
264 affs_remove_header(struct dentry *dentry)
265 {
266 	struct super_block *sb;
267 	struct inode *inode, *dir;
268 	struct buffer_head *bh = NULL;
269 	int retval;
270 
271 	dir = dentry->d_parent->d_inode;
272 	sb = dir->i_sb;
273 
274 	retval = -ENOENT;
275 	inode = dentry->d_inode;
276 	if (!inode)
277 		goto done;
278 
279 	pr_debug("AFFS: remove_header(key=%ld)\n", inode->i_ino);
280 	retval = -EIO;
281 	bh = affs_bread(sb, (u32)(long)dentry->d_fsdata);
282 	if (!bh)
283 		goto done;
284 
285 	affs_lock_link(inode);
286 	affs_lock_dir(dir);
287 	switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
288 	case ST_USERDIR:
289 		/* if we ever want to support links to dirs
290 		 * i_hash_lock of the inode must only be
291 		 * taken after some checks
292 		 */
293 		affs_lock_dir(inode);
294 		retval = affs_empty_dir(inode);
295 		affs_unlock_dir(inode);
296 		if (retval)
297 			goto done_unlock;
298 		break;
299 	default:
300 		break;
301 	}
302 
303 	retval = affs_remove_hash(dir, bh);
304 	if (retval)
305 		goto done_unlock;
306 	mark_buffer_dirty_inode(bh, inode);
307 
308 	affs_unlock_dir(dir);
309 
310 	if (inode->i_nlink > 1)
311 		retval = affs_remove_link(dentry);
312 	else
313 		inode->i_nlink = 0;
314 	affs_unlock_link(inode);
315 	inode->i_ctime = CURRENT_TIME_SEC;
316 	mark_inode_dirty(inode);
317 
318 done:
319 	affs_brelse(bh);
320 	return retval;
321 
322 done_unlock:
323 	affs_unlock_dir(dir);
324 	affs_unlock_link(inode);
325 	goto done;
326 }
327 
328 /* Checksum a block, do various consistency checks and optionally return
329    the blocks type number.  DATA points to the block.  If their pointers
330    are non-null, *PTYPE and *STYPE are set to the primary and secondary
331    block types respectively, *HASHSIZE is set to the size of the hashtable
332    (which lets us calculate the block size).
333    Returns non-zero if the block is not consistent. */
334 
335 u32
336 affs_checksum_block(struct super_block *sb, struct buffer_head *bh)
337 {
338 	__be32 *ptr = (__be32 *)bh->b_data;
339 	u32 sum;
340 	int bsize;
341 
342 	sum = 0;
343 	for (bsize = sb->s_blocksize / sizeof(__be32); bsize > 0; bsize--)
344 		sum += be32_to_cpu(*ptr++);
345 	return sum;
346 }
347 
348 /*
349  * Calculate the checksum of a disk block and store it
350  * at the indicated position.
351  */
352 
353 void
354 affs_fix_checksum(struct super_block *sb, struct buffer_head *bh)
355 {
356 	int cnt = sb->s_blocksize / sizeof(__be32);
357 	__be32 *ptr = (__be32 *)bh->b_data;
358 	u32 checksum;
359 	__be32 *checksumptr;
360 
361 	checksumptr = ptr + 5;
362 	*checksumptr = 0;
363 	for (checksum = 0; cnt > 0; ptr++, cnt--)
364 		checksum += be32_to_cpu(*ptr);
365 	*checksumptr = cpu_to_be32(-checksum);
366 }
367 
368 void
369 secs_to_datestamp(time_t secs, struct affs_date *ds)
370 {
371 	u32	 days;
372 	u32	 minute;
373 
374 	secs -= sys_tz.tz_minuteswest * 60 + ((8 * 365 + 2) * 24 * 60 * 60);
375 	if (secs < 0)
376 		secs = 0;
377 	days    = secs / 86400;
378 	secs   -= days * 86400;
379 	minute  = secs / 60;
380 	secs   -= minute * 60;
381 
382 	ds->days = cpu_to_be32(days);
383 	ds->mins = cpu_to_be32(minute);
384 	ds->ticks = cpu_to_be32(secs * 50);
385 }
386 
387 mode_t
388 prot_to_mode(u32 prot)
389 {
390 	int mode = 0;
391 
392 	if (!(prot & FIBF_NOWRITE))
393 		mode |= S_IWUSR;
394 	if (!(prot & FIBF_NOREAD))
395 		mode |= S_IRUSR;
396 	if (!(prot & FIBF_NOEXECUTE))
397 		mode |= S_IXUSR;
398 	if (prot & FIBF_GRP_WRITE)
399 		mode |= S_IWGRP;
400 	if (prot & FIBF_GRP_READ)
401 		mode |= S_IRGRP;
402 	if (prot & FIBF_GRP_EXECUTE)
403 		mode |= S_IXGRP;
404 	if (prot & FIBF_OTR_WRITE)
405 		mode |= S_IWOTH;
406 	if (prot & FIBF_OTR_READ)
407 		mode |= S_IROTH;
408 	if (prot & FIBF_OTR_EXECUTE)
409 		mode |= S_IXOTH;
410 
411 	return mode;
412 }
413 
414 void
415 mode_to_prot(struct inode *inode)
416 {
417 	u32 prot = AFFS_I(inode)->i_protect;
418 	mode_t mode = inode->i_mode;
419 
420 	if (!(mode & S_IXUSR))
421 		prot |= FIBF_NOEXECUTE;
422 	if (!(mode & S_IRUSR))
423 		prot |= FIBF_NOREAD;
424 	if (!(mode & S_IWUSR))
425 		prot |= FIBF_NOWRITE;
426 	if (mode & S_IXGRP)
427 		prot |= FIBF_GRP_EXECUTE;
428 	if (mode & S_IRGRP)
429 		prot |= FIBF_GRP_READ;
430 	if (mode & S_IWGRP)
431 		prot |= FIBF_GRP_WRITE;
432 	if (mode & S_IXOTH)
433 		prot |= FIBF_OTR_EXECUTE;
434 	if (mode & S_IROTH)
435 		prot |= FIBF_OTR_READ;
436 	if (mode & S_IWOTH)
437 		prot |= FIBF_OTR_WRITE;
438 
439 	AFFS_I(inode)->i_protect = prot;
440 }
441 
442 void
443 affs_error(struct super_block *sb, const char *function, const char *fmt, ...)
444 {
445 	va_list	 args;
446 
447 	va_start(args,fmt);
448 	vsnprintf(ErrorBuffer,sizeof(ErrorBuffer),fmt,args);
449 	va_end(args);
450 
451 	printk(KERN_CRIT "AFFS error (device %s): %s(): %s\n", sb->s_id,
452 		function,ErrorBuffer);
453 	if (!(sb->s_flags & MS_RDONLY))
454 		printk(KERN_WARNING "AFFS: Remounting filesystem read-only\n");
455 	sb->s_flags |= MS_RDONLY;
456 }
457 
458 void
459 affs_warning(struct super_block *sb, const char *function, const char *fmt, ...)
460 {
461 	va_list	 args;
462 
463 	va_start(args,fmt);
464 	vsnprintf(ErrorBuffer,sizeof(ErrorBuffer),fmt,args);
465 	va_end(args);
466 
467 	printk(KERN_WARNING "AFFS warning (device %s): %s(): %s\n", sb->s_id,
468 		function,ErrorBuffer);
469 }
470 
471 /* Check if the name is valid for a affs object. */
472 
473 int
474 affs_check_name(const unsigned char *name, int len)
475 {
476 	int	 i;
477 
478 	if (len > 30)
479 #ifdef AFFS_NO_TRUNCATE
480 		return -ENAMETOOLONG;
481 #else
482 		len = 30;
483 #endif
484 
485 	for (i = 0; i < len; i++) {
486 		if (name[i] < ' ' || name[i] == ':'
487 		    || (name[i] > 0x7e && name[i] < 0xa0))
488 			return -EINVAL;
489 	}
490 
491 	return 0;
492 }
493 
494 /* This function copies name to bstr, with at most 30
495  * characters length. The bstr will be prepended by
496  * a length byte.
497  * NOTE: The name will must be already checked by
498  *       affs_check_name()!
499  */
500 
501 int
502 affs_copy_name(unsigned char *bstr, struct dentry *dentry)
503 {
504 	int len = min(dentry->d_name.len, 30u);
505 
506 	*bstr++ = len;
507 	memcpy(bstr, dentry->d_name.name, len);
508 	return len;
509 }
510