xref: /openbmc/linux/fs/affs/amigaffs.c (revision 68198dca)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/affs/amigaffs.c
4  *
5  *  (c) 1996  Hans-Joachim Widmaier - Rewritten
6  *
7  *  (C) 1993  Ray Burr - Amiga FFS filesystem.
8  *
9  *  Please send bug reports to: hjw@zvw.de
10  */
11 
12 #include <linux/math64.h>
13 #include "affs.h"
14 
15 /*
16  * Functions for accessing Amiga-FFS structures.
17  */
18 
19 
20 /* Insert a header block bh into the directory dir
21  * caller must hold AFFS_DIR->i_hash_lock!
22  */
23 
24 int
25 affs_insert_hash(struct inode *dir, struct buffer_head *bh)
26 {
27 	struct super_block *sb = dir->i_sb;
28 	struct buffer_head *dir_bh;
29 	u32 ino, hash_ino;
30 	int offset;
31 
32 	ino = bh->b_blocknr;
33 	offset = affs_hash_name(sb, AFFS_TAIL(sb, bh)->name + 1, AFFS_TAIL(sb, bh)->name[0]);
34 
35 	pr_debug("%s(dir=%lu, ino=%d)\n", __func__, dir->i_ino, ino);
36 
37 	dir_bh = affs_bread(sb, dir->i_ino);
38 	if (!dir_bh)
39 		return -EIO;
40 
41 	hash_ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[offset]);
42 	while (hash_ino) {
43 		affs_brelse(dir_bh);
44 		dir_bh = affs_bread(sb, hash_ino);
45 		if (!dir_bh)
46 			return -EIO;
47 		hash_ino = be32_to_cpu(AFFS_TAIL(sb, dir_bh)->hash_chain);
48 	}
49 	AFFS_TAIL(sb, bh)->parent = cpu_to_be32(dir->i_ino);
50 	AFFS_TAIL(sb, bh)->hash_chain = 0;
51 	affs_fix_checksum(sb, bh);
52 
53 	if (dir->i_ino == dir_bh->b_blocknr)
54 		AFFS_HEAD(dir_bh)->table[offset] = cpu_to_be32(ino);
55 	else
56 		AFFS_TAIL(sb, dir_bh)->hash_chain = cpu_to_be32(ino);
57 
58 	affs_adjust_checksum(dir_bh, ino);
59 	mark_buffer_dirty_inode(dir_bh, dir);
60 	affs_brelse(dir_bh);
61 
62 	dir->i_mtime = dir->i_ctime = current_time(dir);
63 	dir->i_version++;
64 	mark_inode_dirty(dir);
65 
66 	return 0;
67 }
68 
69 /* Remove a header block from its directory.
70  * caller must hold AFFS_DIR->i_hash_lock!
71  */
72 
73 int
74 affs_remove_hash(struct inode *dir, struct buffer_head *rem_bh)
75 {
76 	struct super_block *sb;
77 	struct buffer_head *bh;
78 	u32 rem_ino, hash_ino;
79 	__be32 ino;
80 	int offset, retval;
81 
82 	sb = dir->i_sb;
83 	rem_ino = rem_bh->b_blocknr;
84 	offset = affs_hash_name(sb, AFFS_TAIL(sb, rem_bh)->name+1, AFFS_TAIL(sb, rem_bh)->name[0]);
85 	pr_debug("%s(dir=%lu, ino=%d, hashval=%d)\n", __func__, dir->i_ino,
86 		 rem_ino, offset);
87 
88 	bh = affs_bread(sb, dir->i_ino);
89 	if (!bh)
90 		return -EIO;
91 
92 	retval = -ENOENT;
93 	hash_ino = be32_to_cpu(AFFS_HEAD(bh)->table[offset]);
94 	while (hash_ino) {
95 		if (hash_ino == rem_ino) {
96 			ino = AFFS_TAIL(sb, rem_bh)->hash_chain;
97 			if (dir->i_ino == bh->b_blocknr)
98 				AFFS_HEAD(bh)->table[offset] = ino;
99 			else
100 				AFFS_TAIL(sb, bh)->hash_chain = ino;
101 			affs_adjust_checksum(bh, be32_to_cpu(ino) - hash_ino);
102 			mark_buffer_dirty_inode(bh, dir);
103 			AFFS_TAIL(sb, rem_bh)->parent = 0;
104 			retval = 0;
105 			break;
106 		}
107 		affs_brelse(bh);
108 		bh = affs_bread(sb, hash_ino);
109 		if (!bh)
110 			return -EIO;
111 		hash_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
112 	}
113 
114 	affs_brelse(bh);
115 
116 	dir->i_mtime = dir->i_ctime = current_time(dir);
117 	dir->i_version++;
118 	mark_inode_dirty(dir);
119 
120 	return retval;
121 }
122 
123 static void
124 affs_fix_dcache(struct inode *inode, u32 entry_ino)
125 {
126 	struct dentry *dentry;
127 	spin_lock(&inode->i_lock);
128 	hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
129 		if (entry_ino == (u32)(long)dentry->d_fsdata) {
130 			dentry->d_fsdata = (void *)inode->i_ino;
131 			break;
132 		}
133 	}
134 	spin_unlock(&inode->i_lock);
135 }
136 
137 
138 /* Remove header from link chain */
139 
140 static int
141 affs_remove_link(struct dentry *dentry)
142 {
143 	struct inode *dir, *inode = d_inode(dentry);
144 	struct super_block *sb = inode->i_sb;
145 	struct buffer_head *bh, *link_bh = NULL;
146 	u32 link_ino, ino;
147 	int retval;
148 
149 	pr_debug("%s(key=%ld)\n", __func__, inode->i_ino);
150 	retval = -EIO;
151 	bh = affs_bread(sb, inode->i_ino);
152 	if (!bh)
153 		goto done;
154 
155 	link_ino = (u32)(long)dentry->d_fsdata;
156 	if (inode->i_ino == link_ino) {
157 		/* we can't remove the head of the link, as its blocknr is still used as ino,
158 		 * so we remove the block of the first link instead.
159 		 */
160 		link_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain);
161 		link_bh = affs_bread(sb, link_ino);
162 		if (!link_bh)
163 			goto done;
164 
165 		dir = affs_iget(sb, be32_to_cpu(AFFS_TAIL(sb, link_bh)->parent));
166 		if (IS_ERR(dir)) {
167 			retval = PTR_ERR(dir);
168 			goto done;
169 		}
170 
171 		affs_lock_dir(dir);
172 		/*
173 		 * if there's a dentry for that block, make it
174 		 * refer to inode itself.
175 		 */
176 		affs_fix_dcache(inode, link_ino);
177 		retval = affs_remove_hash(dir, link_bh);
178 		if (retval) {
179 			affs_unlock_dir(dir);
180 			goto done;
181 		}
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 			affs_unlock_dir(dir);
188 			goto done;
189 		}
190 		mark_buffer_dirty_inode(bh, inode);
191 
192 		affs_unlock_dir(dir);
193 		iput(dir);
194 	} else {
195 		link_bh = affs_bread(sb, link_ino);
196 		if (!link_bh)
197 			goto done;
198 	}
199 
200 	while ((ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain)) != 0) {
201 		if (ino == link_ino) {
202 			__be32 ino2 = AFFS_TAIL(sb, link_bh)->link_chain;
203 			AFFS_TAIL(sb, bh)->link_chain = ino2;
204 			affs_adjust_checksum(bh, be32_to_cpu(ino2) - link_ino);
205 			mark_buffer_dirty_inode(bh, inode);
206 			retval = 0;
207 			/* Fix the link count, if bh is a normal header block without links */
208 			switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
209 			case ST_LINKDIR:
210 			case ST_LINKFILE:
211 				break;
212 			default:
213 				if (!AFFS_TAIL(sb, bh)->link_chain)
214 					set_nlink(inode, 1);
215 			}
216 			affs_free_block(sb, link_ino);
217 			goto done;
218 		}
219 		affs_brelse(bh);
220 		bh = affs_bread(sb, ino);
221 		if (!bh)
222 			goto done;
223 	}
224 	retval = -ENOENT;
225 done:
226 	affs_brelse(link_bh);
227 	affs_brelse(bh);
228 	return retval;
229 }
230 
231 
232 static int
233 affs_empty_dir(struct inode *inode)
234 {
235 	struct super_block *sb = inode->i_sb;
236 	struct buffer_head *bh;
237 	int retval, size;
238 
239 	retval = -EIO;
240 	bh = affs_bread(sb, inode->i_ino);
241 	if (!bh)
242 		goto done;
243 
244 	retval = -ENOTEMPTY;
245 	for (size = AFFS_SB(sb)->s_hashsize - 1; size >= 0; size--)
246 		if (AFFS_HEAD(bh)->table[size])
247 			goto not_empty;
248 	retval = 0;
249 not_empty:
250 	affs_brelse(bh);
251 done:
252 	return retval;
253 }
254 
255 
256 /* Remove a filesystem object. If the object to be removed has
257  * links to it, one of the links must be changed to inherit
258  * the file or directory. As above, any inode will do.
259  * The buffer will not be freed. If the header is a link, the
260  * block will be marked as free.
261  * This function returns a negative error number in case of
262  * an error, else 0 if the inode is to be deleted or 1 if not.
263  */
264 
265 int
266 affs_remove_header(struct dentry *dentry)
267 {
268 	struct super_block *sb;
269 	struct inode *inode, *dir;
270 	struct buffer_head *bh = NULL;
271 	int retval;
272 
273 	dir = d_inode(dentry->d_parent);
274 	sb = dir->i_sb;
275 
276 	retval = -ENOENT;
277 	inode = d_inode(dentry);
278 	if (!inode)
279 		goto done;
280 
281 	pr_debug("%s(key=%ld)\n", __func__, inode->i_ino);
282 	retval = -EIO;
283 	bh = affs_bread(sb, (u32)(long)dentry->d_fsdata);
284 	if (!bh)
285 		goto done;
286 
287 	affs_lock_link(inode);
288 	affs_lock_dir(dir);
289 	switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
290 	case ST_USERDIR:
291 		/* if we ever want to support links to dirs
292 		 * i_hash_lock of the inode must only be
293 		 * taken after some checks
294 		 */
295 		affs_lock_dir(inode);
296 		retval = affs_empty_dir(inode);
297 		affs_unlock_dir(inode);
298 		if (retval)
299 			goto done_unlock;
300 		break;
301 	default:
302 		break;
303 	}
304 
305 	retval = affs_remove_hash(dir, bh);
306 	if (retval)
307 		goto done_unlock;
308 	mark_buffer_dirty_inode(bh, inode);
309 
310 	affs_unlock_dir(dir);
311 
312 	if (inode->i_nlink > 1)
313 		retval = affs_remove_link(dentry);
314 	else
315 		clear_nlink(inode);
316 	affs_unlock_link(inode);
317 	inode->i_ctime = current_time(inode);
318 	mark_inode_dirty(inode);
319 
320 done:
321 	affs_brelse(bh);
322 	return retval;
323 
324 done_unlock:
325 	affs_unlock_dir(dir);
326 	affs_unlock_link(inode);
327 	goto done;
328 }
329 
330 /* Checksum a block, do various consistency checks and optionally return
331    the blocks type number.  DATA points to the block.  If their pointers
332    are non-null, *PTYPE and *STYPE are set to the primary and secondary
333    block types respectively, *HASHSIZE is set to the size of the hashtable
334    (which lets us calculate the block size).
335    Returns non-zero if the block is not consistent. */
336 
337 u32
338 affs_checksum_block(struct super_block *sb, struct buffer_head *bh)
339 {
340 	__be32 *ptr = (__be32 *)bh->b_data;
341 	u32 sum;
342 	int bsize;
343 
344 	sum = 0;
345 	for (bsize = sb->s_blocksize / sizeof(__be32); bsize > 0; bsize--)
346 		sum += be32_to_cpu(*ptr++);
347 	return sum;
348 }
349 
350 /*
351  * Calculate the checksum of a disk block and store it
352  * at the indicated position.
353  */
354 
355 void
356 affs_fix_checksum(struct super_block *sb, struct buffer_head *bh)
357 {
358 	int cnt = sb->s_blocksize / sizeof(__be32);
359 	__be32 *ptr = (__be32 *)bh->b_data;
360 	u32 checksum;
361 	__be32 *checksumptr;
362 
363 	checksumptr = ptr + 5;
364 	*checksumptr = 0;
365 	for (checksum = 0; cnt > 0; ptr++, cnt--)
366 		checksum += be32_to_cpu(*ptr);
367 	*checksumptr = cpu_to_be32(-checksum);
368 }
369 
370 void
371 affs_secs_to_datestamp(time64_t secs, struct affs_date *ds)
372 {
373 	u32	 days;
374 	u32	 minute;
375 	s32	 rem;
376 
377 	secs -= sys_tz.tz_minuteswest * 60 + ((8 * 365 + 2) * 24 * 60 * 60);
378 	if (secs < 0)
379 		secs = 0;
380 	days    = div_s64_rem(secs, 86400, &rem);
381 	minute  = rem / 60;
382 	rem    -= minute * 60;
383 
384 	ds->days = cpu_to_be32(days);
385 	ds->mins = cpu_to_be32(minute);
386 	ds->ticks = cpu_to_be32(rem * 50);
387 }
388 
389 umode_t
390 affs_prot_to_mode(u32 prot)
391 {
392 	umode_t mode = 0;
393 
394 	if (!(prot & FIBF_NOWRITE))
395 		mode |= 0200;
396 	if (!(prot & FIBF_NOREAD))
397 		mode |= 0400;
398 	if (!(prot & FIBF_NOEXECUTE))
399 		mode |= 0100;
400 	if (prot & FIBF_GRP_WRITE)
401 		mode |= 0020;
402 	if (prot & FIBF_GRP_READ)
403 		mode |= 0040;
404 	if (prot & FIBF_GRP_EXECUTE)
405 		mode |= 0010;
406 	if (prot & FIBF_OTR_WRITE)
407 		mode |= 0002;
408 	if (prot & FIBF_OTR_READ)
409 		mode |= 0004;
410 	if (prot & FIBF_OTR_EXECUTE)
411 		mode |= 0001;
412 
413 	return mode;
414 }
415 
416 void
417 affs_mode_to_prot(struct inode *inode)
418 {
419 	u32 prot = AFFS_I(inode)->i_protect;
420 	umode_t mode = inode->i_mode;
421 
422 	if (!(mode & 0100))
423 		prot |= FIBF_NOEXECUTE;
424 	if (!(mode & 0400))
425 		prot |= FIBF_NOREAD;
426 	if (!(mode & 0200))
427 		prot |= FIBF_NOWRITE;
428 	if (mode & 0010)
429 		prot |= FIBF_GRP_EXECUTE;
430 	if (mode & 0040)
431 		prot |= FIBF_GRP_READ;
432 	if (mode & 0020)
433 		prot |= FIBF_GRP_WRITE;
434 	if (mode & 0001)
435 		prot |= FIBF_OTR_EXECUTE;
436 	if (mode & 0004)
437 		prot |= FIBF_OTR_READ;
438 	if (mode & 0002)
439 		prot |= FIBF_OTR_WRITE;
440 
441 	AFFS_I(inode)->i_protect = prot;
442 }
443 
444 void
445 affs_error(struct super_block *sb, const char *function, const char *fmt, ...)
446 {
447 	struct va_format vaf;
448 	va_list args;
449 
450 	va_start(args, fmt);
451 	vaf.fmt = fmt;
452 	vaf.va = &args;
453 	pr_crit("error (device %s): %s(): %pV\n", sb->s_id, function, &vaf);
454 	if (!sb_rdonly(sb))
455 		pr_warn("Remounting filesystem read-only\n");
456 	sb->s_flags |= SB_RDONLY;
457 	va_end(args);
458 }
459 
460 void
461 affs_warning(struct super_block *sb, const char *function, const char *fmt, ...)
462 {
463 	struct va_format vaf;
464 	va_list args;
465 
466 	va_start(args, fmt);
467 	vaf.fmt = fmt;
468 	vaf.va = &args;
469 	pr_warn("(device %s): %s(): %pV\n", sb->s_id, function, &vaf);
470 	va_end(args);
471 }
472 
473 bool
474 affs_nofilenametruncate(const struct dentry *dentry)
475 {
476 	return affs_test_opt(AFFS_SB(dentry->d_sb)->s_flags, SF_NO_TRUNCATE);
477 }
478 
479 /* Check if the name is valid for a affs object. */
480 
481 int
482 affs_check_name(const unsigned char *name, int len, bool notruncate)
483 {
484 	int	 i;
485 
486 	if (len > AFFSNAMEMAX) {
487 		if (notruncate)
488 			return -ENAMETOOLONG;
489 		len = AFFSNAMEMAX;
490 	}
491 	for (i = 0; i < len; i++) {
492 		if (name[i] < ' ' || name[i] == ':'
493 		    || (name[i] > 0x7e && name[i] < 0xa0))
494 			return -EINVAL;
495 	}
496 
497 	return 0;
498 }
499 
500 /* This function copies name to bstr, with at most 30
501  * characters length. The bstr will be prepended by
502  * a length byte.
503  * NOTE: The name will must be already checked by
504  *       affs_check_name()!
505  */
506 
507 int
508 affs_copy_name(unsigned char *bstr, struct dentry *dentry)
509 {
510 	u32 len = min(dentry->d_name.len, AFFSNAMEMAX);
511 
512 	*bstr++ = len;
513 	memcpy(bstr, dentry->d_name.name, len);
514 	return len;
515 }
516