xref: /linux/fs/fat/dir.c (revision 367b8112fe2ea5c39a7bb4d263dcdd9b612fae18)
1 /*
2  *  linux/fs/fat/dir.c
3  *
4  *  directory handling functions for fat-based filesystems
5  *
6  *  Written 1992,1993 by Werner Almesberger
7  *
8  *  Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
9  *
10  *  VFAT extensions by Gordon Chaffee <chaffee@plateau.cs.berkeley.edu>
11  *  Merged with msdos fs by Henrik Storner <storner@osiris.ping.dk>
12  *  Rewritten for constant inumbers. Plugged buffer overrun in readdir(). AV
13  *  Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>
14  */
15 
16 #include <linux/module.h>
17 #include <linux/slab.h>
18 #include <linux/time.h>
19 #include <linux/msdos_fs.h>
20 #include <linux/smp_lock.h>
21 #include <linux/buffer_head.h>
22 #include <linux/compat.h>
23 #include <asm/uaccess.h>
24 
25 static inline loff_t fat_make_i_pos(struct super_block *sb,
26 				    struct buffer_head *bh,
27 				    struct msdos_dir_entry *de)
28 {
29 	return ((loff_t)bh->b_blocknr << MSDOS_SB(sb)->dir_per_block_bits)
30 		| (de - (struct msdos_dir_entry *)bh->b_data);
31 }
32 
33 static inline void fat_dir_readahead(struct inode *dir, sector_t iblock,
34 				     sector_t phys)
35 {
36 	struct super_block *sb = dir->i_sb;
37 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
38 	struct buffer_head *bh;
39 	int sec;
40 
41 	/* This is not a first sector of cluster, or sec_per_clus == 1 */
42 	if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1)
43 		return;
44 	/* root dir of FAT12/FAT16 */
45 	if ((sbi->fat_bits != 32) && (dir->i_ino == MSDOS_ROOT_INO))
46 		return;
47 
48 	bh = sb_find_get_block(sb, phys);
49 	if (bh == NULL || !buffer_uptodate(bh)) {
50 		for (sec = 0; sec < sbi->sec_per_clus; sec++)
51 			sb_breadahead(sb, phys + sec);
52 	}
53 	brelse(bh);
54 }
55 
56 /* Returns the inode number of the directory entry at offset pos. If bh is
57    non-NULL, it is brelse'd before. Pos is incremented. The buffer header is
58    returned in bh.
59    AV. Most often we do it item-by-item. Makes sense to optimize.
60    AV. OK, there we go: if both bh and de are non-NULL we assume that we just
61    AV. want the next entry (took one explicit de=NULL in vfat/namei.c).
62    AV. It's done in fat_get_entry() (inlined), here the slow case lives.
63    AV. Additionally, when we return -1 (i.e. reached the end of directory)
64    AV. we make bh NULL.
65  */
66 static int fat__get_entry(struct inode *dir, loff_t *pos,
67 			  struct buffer_head **bh, struct msdos_dir_entry **de)
68 {
69 	struct super_block *sb = dir->i_sb;
70 	sector_t phys, iblock;
71 	unsigned long mapped_blocks;
72 	int err, offset;
73 
74 next:
75 	if (*bh)
76 		brelse(*bh);
77 
78 	*bh = NULL;
79 	iblock = *pos >> sb->s_blocksize_bits;
80 	err = fat_bmap(dir, iblock, &phys, &mapped_blocks);
81 	if (err || !phys)
82 		return -1;	/* beyond EOF or error */
83 
84 	fat_dir_readahead(dir, iblock, phys);
85 
86 	*bh = sb_bread(sb, phys);
87 	if (*bh == NULL) {
88 		printk(KERN_ERR "FAT: Directory bread(block %llu) failed\n",
89 		       (unsigned long long)phys);
90 		/* skip this block */
91 		*pos = (iblock + 1) << sb->s_blocksize_bits;
92 		goto next;
93 	}
94 
95 	offset = *pos & (sb->s_blocksize - 1);
96 	*pos += sizeof(struct msdos_dir_entry);
97 	*de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
98 
99 	return 0;
100 }
101 
102 static inline int fat_get_entry(struct inode *dir, loff_t *pos,
103 				struct buffer_head **bh,
104 				struct msdos_dir_entry **de)
105 {
106 	/* Fast stuff first */
107 	if (*bh && *de &&
108 	    (*de - (struct msdos_dir_entry *)(*bh)->b_data) < MSDOS_SB(dir->i_sb)->dir_per_block - 1) {
109 		*pos += sizeof(struct msdos_dir_entry);
110 		(*de)++;
111 		return 0;
112 	}
113 	return fat__get_entry(dir, pos, bh, de);
114 }
115 
116 /*
117  * Convert Unicode 16 to UTF-8, translated Unicode, or ASCII.
118  * If uni_xlate is enabled and we can't get a 1:1 conversion, use a
119  * colon as an escape character since it is normally invalid on the vfat
120  * filesystem. The following four characters are the hexadecimal digits
121  * of Unicode value. This lets us do a full dump and restore of Unicode
122  * filenames. We could get into some trouble with long Unicode names,
123  * but ignore that right now.
124  * Ahem... Stack smashing in ring 0 isn't fun. Fixed.
125  */
126 static int uni16_to_x8(unsigned char *ascii, const wchar_t *uni, int len,
127 		       int uni_xlate, struct nls_table *nls)
128 {
129 	const wchar_t *ip;
130 	wchar_t ec;
131 	unsigned char *op, nc;
132 	int charlen;
133 	int k;
134 
135 	ip = uni;
136 	op = ascii;
137 
138 	while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {
139 		ec = *ip++;
140 		if ( (charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE)) > 0) {
141 			op += charlen;
142 			len -= charlen;
143 		} else {
144 			if (uni_xlate == 1) {
145 				*op = ':';
146 				for (k = 4; k > 0; k--) {
147 					nc = ec & 0xF;
148 					op[k] = nc > 9	? nc + ('a' - 10)
149 							: nc + '0';
150 					ec >>= 4;
151 				}
152 				op += 5;
153 				len -= 5;
154 			} else {
155 				*op++ = '?';
156 				len--;
157 			}
158 		}
159 	}
160 
161 	if (unlikely(*ip)) {
162 		printk(KERN_WARNING "FAT: filename was truncated while "
163 		       "converting.");
164 	}
165 
166 	*op = 0;
167 	return (op - ascii);
168 }
169 
170 static inline int fat_uni_to_x8(struct msdos_sb_info *sbi, const wchar_t *uni,
171 				unsigned char *buf, int size)
172 {
173 	if (sbi->options.utf8)
174 		return utf8_wcstombs(buf, uni, size);
175 	else
176 		return uni16_to_x8(buf, uni, size, sbi->options.unicode_xlate,
177 				   sbi->nls_io);
178 }
179 
180 static inline int
181 fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
182 {
183 	int charlen;
184 
185 	charlen = t->char2uni(c, clen, uni);
186 	if (charlen < 0) {
187 		*uni = 0x003f;	/* a question mark */
188 		charlen = 1;
189 	}
190 	return charlen;
191 }
192 
193 static inline int
194 fat_short2lower_uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
195 {
196 	int charlen;
197 	wchar_t wc;
198 
199 	charlen = t->char2uni(c, clen, &wc);
200 	if (charlen < 0) {
201 		*uni = 0x003f;	/* a question mark */
202 		charlen = 1;
203 	} else if (charlen <= 1) {
204 		unsigned char nc = t->charset2lower[*c];
205 
206 		if (!nc)
207 			nc = *c;
208 
209 		if ( (charlen = t->char2uni(&nc, 1, uni)) < 0) {
210 			*uni = 0x003f;	/* a question mark */
211 			charlen = 1;
212 		}
213 	} else
214 		*uni = wc;
215 
216 	return charlen;
217 }
218 
219 static inline int
220 fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size,
221 		  wchar_t *uni_buf, unsigned short opt, int lower)
222 {
223 	int len = 0;
224 
225 	if (opt & VFAT_SFN_DISPLAY_LOWER)
226 		len =  fat_short2lower_uni(nls, buf, buf_size, uni_buf);
227 	else if (opt & VFAT_SFN_DISPLAY_WIN95)
228 		len = fat_short2uni(nls, buf, buf_size, uni_buf);
229 	else if (opt & VFAT_SFN_DISPLAY_WINNT) {
230 		if (lower)
231 			len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
232 		else
233 			len = fat_short2uni(nls, buf, buf_size, uni_buf);
234 	} else
235 		len = fat_short2uni(nls, buf, buf_size, uni_buf);
236 
237 	return len;
238 }
239 
240 static inline int fat_name_match(struct msdos_sb_info *sbi,
241 				 const unsigned char *a, int a_len,
242 				 const unsigned char *b, int b_len)
243 {
244 	if (a_len != b_len)
245 		return 0;
246 
247 	if (sbi->options.name_check != 's')
248 		return !nls_strnicmp(sbi->nls_io, a, b, a_len);
249 	else
250 		return !memcmp(a, b, a_len);
251 }
252 
253 enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, };
254 
255 /**
256  * fat_parse_long - Parse extended directory entry.
257  *
258  * This function returns zero on success, negative value on error, or one of
259  * the following:
260  *
261  * %PARSE_INVALID - Directory entry is invalid.
262  * %PARSE_NOT_LONGNAME - Directory entry does not contain longname.
263  * %PARSE_EOF - Directory has no more entries.
264  */
265 static int fat_parse_long(struct inode *dir, loff_t *pos,
266 			  struct buffer_head **bh, struct msdos_dir_entry **de,
267 			  wchar_t **unicode, unsigned char *nr_slots)
268 {
269 	struct msdos_dir_slot *ds;
270 	unsigned char id, slot, slots, alias_checksum;
271 
272 	if (!*unicode) {
273 		*unicode = __getname();
274 		if (!*unicode) {
275 			brelse(*bh);
276 			return -ENOMEM;
277 		}
278 	}
279 parse_long:
280 	slots = 0;
281 	ds = (struct msdos_dir_slot *)*de;
282 	id = ds->id;
283 	if (!(id & 0x40))
284 		return PARSE_INVALID;
285 	slots = id & ~0x40;
286 	if (slots > 20 || !slots)	/* ceil(256 * 2 / 26) */
287 		return PARSE_INVALID;
288 	*nr_slots = slots;
289 	alias_checksum = ds->alias_checksum;
290 
291 	slot = slots;
292 	while (1) {
293 		int offset;
294 
295 		slot--;
296 		offset = slot * 13;
297 		fat16_towchar(*unicode + offset, ds->name0_4, 5);
298 		fat16_towchar(*unicode + offset + 5, ds->name5_10, 6);
299 		fat16_towchar(*unicode + offset + 11, ds->name11_12, 2);
300 
301 		if (ds->id & 0x40)
302 			(*unicode)[offset + 13] = 0;
303 		if (fat_get_entry(dir, pos, bh, de) < 0)
304 			return PARSE_EOF;
305 		if (slot == 0)
306 			break;
307 		ds = (struct msdos_dir_slot *)*de;
308 		if (ds->attr != ATTR_EXT)
309 			return PARSE_NOT_LONGNAME;
310 		if ((ds->id & ~0x40) != slot)
311 			goto parse_long;
312 		if (ds->alias_checksum != alias_checksum)
313 			goto parse_long;
314 	}
315 	if ((*de)->name[0] == DELETED_FLAG)
316 		return PARSE_INVALID;
317 	if ((*de)->attr == ATTR_EXT)
318 		goto parse_long;
319 	if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME))
320 		return PARSE_INVALID;
321 	if (fat_checksum((*de)->name) != alias_checksum)
322 		*nr_slots = 0;
323 
324 	return 0;
325 }
326 
327 /*
328  * Maximum buffer size of short name.
329  * [(MSDOS_NAME + '.') * max one char + nul]
330  * For msdos style, ['.' (hidden) + MSDOS_NAME + '.' + nul]
331  */
332 #define FAT_MAX_SHORT_SIZE	((MSDOS_NAME + 1) * NLS_MAX_CHARSET_SIZE + 1)
333 /*
334  * Maximum buffer size of unicode chars from slots.
335  * [(max longname slots * 13 (size in a slot) + nul) * sizeof(wchar_t)]
336  */
337 #define FAT_MAX_UNI_CHARS	((MSDOS_SLOTS - 1) * 13 + 1)
338 #define FAT_MAX_UNI_SIZE	(FAT_MAX_UNI_CHARS * sizeof(wchar_t))
339 
340 /*
341  * Return values: negative -> error, 0 -> not found, positive -> found,
342  * value is the total amount of slots, including the shortname entry.
343  */
344 int fat_search_long(struct inode *inode, const unsigned char *name,
345 		    int name_len, struct fat_slot_info *sinfo)
346 {
347 	struct super_block *sb = inode->i_sb;
348 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
349 	struct buffer_head *bh = NULL;
350 	struct msdos_dir_entry *de;
351 	struct nls_table *nls_disk = sbi->nls_disk;
352 	unsigned char nr_slots;
353 	wchar_t bufuname[14];
354 	wchar_t *unicode = NULL;
355 	unsigned char work[MSDOS_NAME];
356 	unsigned char bufname[FAT_MAX_SHORT_SIZE];
357 	unsigned short opt_shortname = sbi->options.shortname;
358 	loff_t cpos = 0;
359 	int chl, i, j, last_u, err, len;
360 
361 	err = -ENOENT;
362 	while (1) {
363 		if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
364 			goto end_of_dir;
365 parse_record:
366 		nr_slots = 0;
367 		if (de->name[0] == DELETED_FLAG)
368 			continue;
369 		if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
370 			continue;
371 		if (de->attr != ATTR_EXT && IS_FREE(de->name))
372 			continue;
373 		if (de->attr == ATTR_EXT) {
374 			int status = fat_parse_long(inode, &cpos, &bh, &de,
375 						    &unicode, &nr_slots);
376 			if (status < 0)
377 				return status;
378 			else if (status == PARSE_INVALID)
379 				continue;
380 			else if (status == PARSE_NOT_LONGNAME)
381 				goto parse_record;
382 			else if (status == PARSE_EOF)
383 				goto end_of_dir;
384 		}
385 
386 		memcpy(work, de->name, sizeof(de->name));
387 		/* see namei.c, msdos_format_name */
388 		if (work[0] == 0x05)
389 			work[0] = 0xE5;
390 		for (i = 0, j = 0, last_u = 0; i < 8;) {
391 			if (!work[i])
392 				break;
393 			chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
394 						&bufuname[j++], opt_shortname,
395 						de->lcase & CASE_LOWER_BASE);
396 			if (chl <= 1) {
397 				if (work[i] != ' ')
398 					last_u = j;
399 			} else {
400 				last_u = j;
401 			}
402 			i += chl;
403 		}
404 		j = last_u;
405 		fat_short2uni(nls_disk, ".", 1, &bufuname[j++]);
406 		for (i = 8; i < MSDOS_NAME;) {
407 			if (!work[i])
408 				break;
409 			chl = fat_shortname2uni(nls_disk, &work[i],
410 						MSDOS_NAME - i,
411 						&bufuname[j++], opt_shortname,
412 						de->lcase & CASE_LOWER_EXT);
413 			if (chl <= 1) {
414 				if (work[i] != ' ')
415 					last_u = j;
416 			} else {
417 				last_u = j;
418 			}
419 			i += chl;
420 		}
421 		if (!last_u)
422 			continue;
423 
424 		/* Compare shortname */
425 		bufuname[last_u] = 0x0000;
426 		len = fat_uni_to_x8(sbi, bufuname, bufname, sizeof(bufname));
427 		if (fat_name_match(sbi, name, name_len, bufname, len))
428 			goto found;
429 
430 		if (nr_slots) {
431 			void *longname = unicode + FAT_MAX_UNI_CHARS;
432 			int size = PATH_MAX - FAT_MAX_UNI_SIZE;
433 
434 			/* Compare longname */
435 			len = fat_uni_to_x8(sbi, unicode, longname, size);
436 			if (fat_name_match(sbi, name, name_len, longname, len))
437 				goto found;
438 		}
439 	}
440 
441 found:
442 	nr_slots++;	/* include the de */
443 	sinfo->slot_off = cpos - nr_slots * sizeof(*de);
444 	sinfo->nr_slots = nr_slots;
445 	sinfo->de = de;
446 	sinfo->bh = bh;
447 	sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
448 	err = 0;
449 end_of_dir:
450 	if (unicode)
451 		__putname(unicode);
452 
453 	return err;
454 }
455 
456 EXPORT_SYMBOL_GPL(fat_search_long);
457 
458 struct fat_ioctl_filldir_callback {
459 	void __user *dirent;
460 	int result;
461 	/* for dir ioctl */
462 	const char *longname;
463 	int long_len;
464 	const char *shortname;
465 	int short_len;
466 };
467 
468 static int __fat_readdir(struct inode *inode, struct file *filp, void *dirent,
469 			 filldir_t filldir, int short_only, int both)
470 {
471 	struct super_block *sb = inode->i_sb;
472 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
473 	struct buffer_head *bh;
474 	struct msdos_dir_entry *de;
475 	struct nls_table *nls_disk = sbi->nls_disk;
476 	unsigned char nr_slots;
477 	wchar_t bufuname[14];
478 	wchar_t *unicode = NULL;
479 	unsigned char c, work[MSDOS_NAME];
480 	unsigned char bufname[FAT_MAX_SHORT_SIZE], *ptname = bufname;
481 	unsigned short opt_shortname = sbi->options.shortname;
482 	int isvfat = sbi->options.isvfat;
483 	int nocase = sbi->options.nocase;
484 	const char *fill_name = NULL;
485 	unsigned long inum;
486 	unsigned long lpos, dummy, *furrfu = &lpos;
487 	loff_t cpos;
488 	int chi, chl, i, i2, j, last, last_u, dotoffset = 0, fill_len = 0;
489 	int ret = 0;
490 
491 	lock_super(sb);
492 
493 	cpos = filp->f_pos;
494 	/* Fake . and .. for the root directory. */
495 	if (inode->i_ino == MSDOS_ROOT_INO) {
496 		while (cpos < 2) {
497 			if (filldir(dirent, "..", cpos+1, cpos, MSDOS_ROOT_INO, DT_DIR) < 0)
498 				goto out;
499 			cpos++;
500 			filp->f_pos++;
501 		}
502 		if (cpos == 2) {
503 			dummy = 2;
504 			furrfu = &dummy;
505 			cpos = 0;
506 		}
507 	}
508 	if (cpos & (sizeof(struct msdos_dir_entry) - 1)) {
509 		ret = -ENOENT;
510 		goto out;
511 	}
512 
513 	bh = NULL;
514 get_new:
515 	if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
516 		goto end_of_dir;
517 parse_record:
518 	nr_slots = 0;
519 	/*
520 	 * Check for long filename entry, but if short_only, we don't
521 	 * need to parse long filename.
522 	 */
523 	if (isvfat && !short_only) {
524 		if (de->name[0] == DELETED_FLAG)
525 			goto record_end;
526 		if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
527 			goto record_end;
528 		if (de->attr != ATTR_EXT && IS_FREE(de->name))
529 			goto record_end;
530 	} else {
531 		if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))
532 			goto record_end;
533 	}
534 
535 	if (isvfat && de->attr == ATTR_EXT) {
536 		int status = fat_parse_long(inode, &cpos, &bh, &de,
537 					    &unicode, &nr_slots);
538 		if (status < 0) {
539 			filp->f_pos = cpos;
540 			ret = status;
541 			goto out;
542 		} else if (status == PARSE_INVALID)
543 			goto record_end;
544 		else if (status == PARSE_NOT_LONGNAME)
545 			goto parse_record;
546 		else if (status == PARSE_EOF)
547 			goto end_of_dir;
548 
549 		if (nr_slots) {
550 			void *longname = unicode + FAT_MAX_UNI_CHARS;
551 			int size = PATH_MAX - FAT_MAX_UNI_SIZE;
552 			int len = fat_uni_to_x8(sbi, unicode, longname, size);
553 
554 			fill_name = longname;
555 			fill_len = len;
556 			/* !both && !short_only, so we don't need shortname. */
557 			if (!both)
558 				goto start_filldir;
559 		}
560 	}
561 
562 	if (sbi->options.dotsOK) {
563 		ptname = bufname;
564 		dotoffset = 0;
565 		if (de->attr & ATTR_HIDDEN) {
566 			*ptname++ = '.';
567 			dotoffset = 1;
568 		}
569 	}
570 
571 	memcpy(work, de->name, sizeof(de->name));
572 	/* see namei.c, msdos_format_name */
573 	if (work[0] == 0x05)
574 		work[0] = 0xE5;
575 	for (i = 0, j = 0, last = 0, last_u = 0; i < 8;) {
576 		if (!(c = work[i]))
577 			break;
578 		chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
579 					&bufuname[j++], opt_shortname,
580 					de->lcase & CASE_LOWER_BASE);
581 		if (chl <= 1) {
582 			ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c;
583 			if (c != ' ') {
584 				last = i;
585 				last_u = j;
586 			}
587 		} else {
588 			last_u = j;
589 			for (chi = 0; chi < chl && i < 8; chi++) {
590 				ptname[i] = work[i];
591 				i++; last = i;
592 			}
593 		}
594 	}
595 	i = last;
596 	j = last_u;
597 	fat_short2uni(nls_disk, ".", 1, &bufuname[j++]);
598 	ptname[i++] = '.';
599 	for (i2 = 8; i2 < MSDOS_NAME;) {
600 		if (!(c = work[i2]))
601 			break;
602 		chl = fat_shortname2uni(nls_disk, &work[i2], MSDOS_NAME - i2,
603 					&bufuname[j++], opt_shortname,
604 					de->lcase & CASE_LOWER_EXT);
605 		if (chl <= 1) {
606 			i2++;
607 			ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c;
608 			if (c != ' ') {
609 				last = i;
610 				last_u = j;
611 			}
612 		} else {
613 			last_u = j;
614 			for (chi = 0; chi < chl && i2 < MSDOS_NAME; chi++) {
615 				ptname[i++] = work[i2++];
616 				last = i;
617 			}
618 		}
619 	}
620 	if (!last)
621 		goto record_end;
622 
623 	i = last + dotoffset;
624 	j = last_u;
625 
626 	if (isvfat) {
627 		bufuname[j] = 0x0000;
628 		i = fat_uni_to_x8(sbi, bufuname, bufname, sizeof(bufname));
629 	}
630 	if (nr_slots) {
631 		/* hack for fat_ioctl_filldir() */
632 		struct fat_ioctl_filldir_callback *p = dirent;
633 
634 		p->longname = fill_name;
635 		p->long_len = fill_len;
636 		p->shortname = bufname;
637 		p->short_len = i;
638 		fill_name = NULL;
639 		fill_len = 0;
640 	} else {
641 		fill_name = bufname;
642 		fill_len = i;
643 	}
644 
645 start_filldir:
646 	lpos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
647 	if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME))
648 		inum = inode->i_ino;
649 	else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
650 		inum = parent_ino(filp->f_path.dentry);
651 	} else {
652 		loff_t i_pos = fat_make_i_pos(sb, bh, de);
653 		struct inode *tmp = fat_iget(sb, i_pos);
654 		if (tmp) {
655 			inum = tmp->i_ino;
656 			iput(tmp);
657 		} else
658 			inum = iunique(sb, MSDOS_ROOT_INO);
659 	}
660 
661 	if (filldir(dirent, fill_name, fill_len, *furrfu, inum,
662 		    (de->attr & ATTR_DIR) ? DT_DIR : DT_REG) < 0)
663 		goto fill_failed;
664 
665 record_end:
666 	furrfu = &lpos;
667 	filp->f_pos = cpos;
668 	goto get_new;
669 end_of_dir:
670 	filp->f_pos = cpos;
671 fill_failed:
672 	brelse(bh);
673 	if (unicode)
674 		__putname(unicode);
675 out:
676 	unlock_super(sb);
677 	return ret;
678 }
679 
680 static int fat_readdir(struct file *filp, void *dirent, filldir_t filldir)
681 {
682 	struct inode *inode = filp->f_path.dentry->d_inode;
683 	return __fat_readdir(inode, filp, dirent, filldir, 0, 0);
684 }
685 
686 #define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type)			   \
687 static int func(void *__buf, const char *name, int name_len,		   \
688 			     loff_t offset, u64 ino, unsigned int d_type)  \
689 {									   \
690 	struct fat_ioctl_filldir_callback *buf = __buf;			   \
691 	struct dirent_type __user *d1 = buf->dirent;			   \
692 	struct dirent_type __user *d2 = d1 + 1;				   \
693 									   \
694 	if (buf->result)						   \
695 		return -EINVAL;						   \
696 	buf->result++;							   \
697 									   \
698 	if (name != NULL) {						   \
699 		/* dirent has only short name */			   \
700 		if (name_len >= sizeof(d1->d_name))			   \
701 			name_len = sizeof(d1->d_name) - 1;		   \
702 									   \
703 		if (put_user(0, d2->d_name)			||	   \
704 		    put_user(0, &d2->d_reclen)			||	   \
705 		    copy_to_user(d1->d_name, name, name_len)	||	   \
706 		    put_user(0, d1->d_name + name_len)		||	   \
707 		    put_user(name_len, &d1->d_reclen))			   \
708 			goto efault;					   \
709 	} else {							   \
710 		/* dirent has short and long name */			   \
711 		const char *longname = buf->longname;			   \
712 		int long_len = buf->long_len;				   \
713 		const char *shortname = buf->shortname;			   \
714 		int short_len = buf->short_len;				   \
715 									   \
716 		if (long_len >= sizeof(d1->d_name))			   \
717 			long_len = sizeof(d1->d_name) - 1;		   \
718 		if (short_len >= sizeof(d1->d_name))			   \
719 			short_len = sizeof(d1->d_name) - 1;		   \
720 									   \
721 		if (copy_to_user(d2->d_name, longname, long_len)	|| \
722 		    put_user(0, d2->d_name + long_len)			|| \
723 		    put_user(long_len, &d2->d_reclen)			|| \
724 		    put_user(ino, &d2->d_ino)				|| \
725 		    put_user(offset, &d2->d_off)			|| \
726 		    copy_to_user(d1->d_name, shortname, short_len)	|| \
727 		    put_user(0, d1->d_name + short_len)			|| \
728 		    put_user(short_len, &d1->d_reclen))			   \
729 			goto efault;					   \
730 	}								   \
731 	return 0;							   \
732 efault:									   \
733 	buf->result = -EFAULT;						   \
734 	return -EFAULT;							   \
735 }
736 
737 FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)
738 
739 static int fat_ioctl_readdir(struct inode *inode, struct file *filp,
740 			     void __user *dirent, filldir_t filldir,
741 			     int short_only, int both)
742 {
743 	struct fat_ioctl_filldir_callback buf;
744 	int ret;
745 
746 	buf.dirent = dirent;
747 	buf.result = 0;
748 	mutex_lock(&inode->i_mutex);
749 	ret = -ENOENT;
750 	if (!IS_DEADDIR(inode)) {
751 		ret = __fat_readdir(inode, filp, &buf, filldir,
752 				    short_only, both);
753 	}
754 	mutex_unlock(&inode->i_mutex);
755 	if (ret >= 0)
756 		ret = buf.result;
757 	return ret;
758 }
759 
760 static int fat_dir_ioctl(struct inode *inode, struct file *filp,
761 			 unsigned int cmd, unsigned long arg)
762 {
763 	struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg;
764 	int short_only, both;
765 
766 	switch (cmd) {
767 	case VFAT_IOCTL_READDIR_SHORT:
768 		short_only = 1;
769 		both = 0;
770 		break;
771 	case VFAT_IOCTL_READDIR_BOTH:
772 		short_only = 0;
773 		both = 1;
774 		break;
775 	default:
776 		return fat_generic_ioctl(inode, filp, cmd, arg);
777 	}
778 
779 	if (!access_ok(VERIFY_WRITE, d1, sizeof(struct __fat_dirent[2])))
780 		return -EFAULT;
781 	/*
782 	 * Yes, we don't need this put_user() absolutely. However old
783 	 * code didn't return the right value. So, app use this value,
784 	 * in order to check whether it is EOF.
785 	 */
786 	if (put_user(0, &d1->d_reclen))
787 		return -EFAULT;
788 
789 	return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir,
790 				 short_only, both);
791 }
792 
793 #ifdef CONFIG_COMPAT
794 #define	VFAT_IOCTL_READDIR_BOTH32	_IOR('r', 1, struct compat_dirent[2])
795 #define	VFAT_IOCTL_READDIR_SHORT32	_IOR('r', 2, struct compat_dirent[2])
796 
797 FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent)
798 
799 static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd,
800 				 unsigned long arg)
801 {
802 	struct inode *inode = filp->f_path.dentry->d_inode;
803 	struct compat_dirent __user *d1 = compat_ptr(arg);
804 	int short_only, both;
805 
806 	switch (cmd) {
807 	case VFAT_IOCTL_READDIR_SHORT32:
808 		short_only = 1;
809 		both = 0;
810 		break;
811 	case VFAT_IOCTL_READDIR_BOTH32:
812 		short_only = 0;
813 		both = 1;
814 		break;
815 	default:
816 		return -ENOIOCTLCMD;
817 	}
818 
819 	if (!access_ok(VERIFY_WRITE, d1, sizeof(struct compat_dirent[2])))
820 		return -EFAULT;
821 	/*
822 	 * Yes, we don't need this put_user() absolutely. However old
823 	 * code didn't return the right value. So, app use this value,
824 	 * in order to check whether it is EOF.
825 	 */
826 	if (put_user(0, &d1->d_reclen))
827 		return -EFAULT;
828 
829 	return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir,
830 				 short_only, both);
831 }
832 #endif /* CONFIG_COMPAT */
833 
834 const struct file_operations fat_dir_operations = {
835 	.read		= generic_read_dir,
836 	.readdir	= fat_readdir,
837 	.ioctl		= fat_dir_ioctl,
838 #ifdef CONFIG_COMPAT
839 	.compat_ioctl	= fat_compat_dir_ioctl,
840 #endif
841 	.fsync		= file_fsync,
842 	.llseek		= generic_file_llseek,
843 };
844 
845 static int fat_get_short_entry(struct inode *dir, loff_t *pos,
846 			       struct buffer_head **bh,
847 			       struct msdos_dir_entry **de)
848 {
849 	while (fat_get_entry(dir, pos, bh, de) >= 0) {
850 		/* free entry or long name entry or volume label */
851 		if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))
852 			return 0;
853 	}
854 	return -ENOENT;
855 }
856 
857 /*
858  * The ".." entry can not provide the "struct fat_slot_info" informations
859  * for inode. So, this function provide the some informations only.
860  */
861 int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
862 			 struct msdos_dir_entry **de, loff_t *i_pos)
863 {
864 	loff_t offset;
865 
866 	offset = 0;
867 	*bh = NULL;
868 	while (fat_get_short_entry(dir, &offset, bh, de) >= 0) {
869 		if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME)) {
870 			*i_pos = fat_make_i_pos(dir->i_sb, *bh, *de);
871 			return 0;
872 		}
873 	}
874 	return -ENOENT;
875 }
876 
877 EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);
878 
879 /* See if directory is empty */
880 int fat_dir_empty(struct inode *dir)
881 {
882 	struct buffer_head *bh;
883 	struct msdos_dir_entry *de;
884 	loff_t cpos;
885 	int result = 0;
886 
887 	bh = NULL;
888 	cpos = 0;
889 	while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
890 		if (strncmp(de->name, MSDOS_DOT   , MSDOS_NAME) &&
891 		    strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
892 			result = -ENOTEMPTY;
893 			break;
894 		}
895 	}
896 	brelse(bh);
897 	return result;
898 }
899 
900 EXPORT_SYMBOL_GPL(fat_dir_empty);
901 
902 /*
903  * fat_subdirs counts the number of sub-directories of dir. It can be run
904  * on directories being created.
905  */
906 int fat_subdirs(struct inode *dir)
907 {
908 	struct buffer_head *bh;
909 	struct msdos_dir_entry *de;
910 	loff_t cpos;
911 	int count = 0;
912 
913 	bh = NULL;
914 	cpos = 0;
915 	while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
916 		if (de->attr & ATTR_DIR)
917 			count++;
918 	}
919 	brelse(bh);
920 	return count;
921 }
922 
923 /*
924  * Scans a directory for a given file (name points to its formatted name).
925  * Returns an error code or zero.
926  */
927 int fat_scan(struct inode *dir, const unsigned char *name,
928 	     struct fat_slot_info *sinfo)
929 {
930 	struct super_block *sb = dir->i_sb;
931 
932 	sinfo->slot_off = 0;
933 	sinfo->bh = NULL;
934 	while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
935 				   &sinfo->de) >= 0) {
936 		if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) {
937 			sinfo->slot_off -= sizeof(*sinfo->de);
938 			sinfo->nr_slots = 1;
939 			sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
940 			return 0;
941 		}
942 	}
943 	return -ENOENT;
944 }
945 
946 EXPORT_SYMBOL_GPL(fat_scan);
947 
948 static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)
949 {
950 	struct super_block *sb = dir->i_sb;
951 	struct buffer_head *bh;
952 	struct msdos_dir_entry *de, *endp;
953 	int err = 0, orig_slots;
954 
955 	while (nr_slots) {
956 		bh = NULL;
957 		if (fat_get_entry(dir, &pos, &bh, &de) < 0) {
958 			err = -EIO;
959 			break;
960 		}
961 
962 		orig_slots = nr_slots;
963 		endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize);
964 		while (nr_slots && de < endp) {
965 			de->name[0] = DELETED_FLAG;
966 			de++;
967 			nr_slots--;
968 		}
969 		mark_buffer_dirty(bh);
970 		if (IS_DIRSYNC(dir))
971 			err = sync_dirty_buffer(bh);
972 		brelse(bh);
973 		if (err)
974 			break;
975 
976 		/* pos is *next* de's position, so this does `- sizeof(de)' */
977 		pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de);
978 	}
979 
980 	return err;
981 }
982 
983 int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)
984 {
985 	struct msdos_dir_entry *de;
986 	struct buffer_head *bh;
987 	int err = 0, nr_slots;
988 
989 	/*
990 	 * First stage: Remove the shortname. By this, the directory
991 	 * entry is removed.
992 	 */
993 	nr_slots = sinfo->nr_slots;
994 	de = sinfo->de;
995 	sinfo->de = NULL;
996 	bh = sinfo->bh;
997 	sinfo->bh = NULL;
998 	while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) {
999 		de->name[0] = DELETED_FLAG;
1000 		de--;
1001 		nr_slots--;
1002 	}
1003 	mark_buffer_dirty(bh);
1004 	if (IS_DIRSYNC(dir))
1005 		err = sync_dirty_buffer(bh);
1006 	brelse(bh);
1007 	if (err)
1008 		return err;
1009 	dir->i_version++;
1010 
1011 	if (nr_slots) {
1012 		/*
1013 		 * Second stage: remove the remaining longname slots.
1014 		 * (This directory entry is already removed, and so return
1015 		 * the success)
1016 		 */
1017 		err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots);
1018 		if (err) {
1019 			printk(KERN_WARNING
1020 			       "FAT: Couldn't remove the long name slots\n");
1021 		}
1022 	}
1023 
1024 	dir->i_mtime = dir->i_atime = CURRENT_TIME_SEC;
1025 	if (IS_DIRSYNC(dir))
1026 		(void)fat_sync_inode(dir);
1027 	else
1028 		mark_inode_dirty(dir);
1029 
1030 	return 0;
1031 }
1032 
1033 EXPORT_SYMBOL_GPL(fat_remove_entries);
1034 
1035 static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,
1036 			      struct buffer_head **bhs, int nr_bhs)
1037 {
1038 	struct super_block *sb = dir->i_sb;
1039 	sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus;
1040 	int err, i, n;
1041 
1042 	/* Zeroing the unused blocks on this cluster */
1043 	blknr += nr_used;
1044 	n = nr_used;
1045 	while (blknr < last_blknr) {
1046 		bhs[n] = sb_getblk(sb, blknr);
1047 		if (!bhs[n]) {
1048 			err = -ENOMEM;
1049 			goto error;
1050 		}
1051 		memset(bhs[n]->b_data, 0, sb->s_blocksize);
1052 		set_buffer_uptodate(bhs[n]);
1053 		mark_buffer_dirty(bhs[n]);
1054 
1055 		n++;
1056 		blknr++;
1057 		if (n == nr_bhs) {
1058 			if (IS_DIRSYNC(dir)) {
1059 				err = fat_sync_bhs(bhs, n);
1060 				if (err)
1061 					goto error;
1062 			}
1063 			for (i = 0; i < n; i++)
1064 				brelse(bhs[i]);
1065 			n = 0;
1066 		}
1067 	}
1068 	if (IS_DIRSYNC(dir)) {
1069 		err = fat_sync_bhs(bhs, n);
1070 		if (err)
1071 			goto error;
1072 	}
1073 	for (i = 0; i < n; i++)
1074 		brelse(bhs[i]);
1075 
1076 	return 0;
1077 
1078 error:
1079 	for (i = 0; i < n; i++)
1080 		bforget(bhs[i]);
1081 	return err;
1082 }
1083 
1084 int fat_alloc_new_dir(struct inode *dir, struct timespec *ts)
1085 {
1086 	struct super_block *sb = dir->i_sb;
1087 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
1088 	struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1089 	struct msdos_dir_entry *de;
1090 	sector_t blknr;
1091 	__le16 date, time;
1092 	int err, cluster;
1093 
1094 	err = fat_alloc_clusters(dir, &cluster, 1);
1095 	if (err)
1096 		goto error;
1097 
1098 	blknr = fat_clus_to_blknr(sbi, cluster);
1099 	bhs[0] = sb_getblk(sb, blknr);
1100 	if (!bhs[0]) {
1101 		err = -ENOMEM;
1102 		goto error_free;
1103 	}
1104 
1105 	fat_date_unix2dos(ts->tv_sec, &time, &date, sbi->options.tz_utc);
1106 
1107 	de = (struct msdos_dir_entry *)bhs[0]->b_data;
1108 	/* filling the new directory slots ("." and ".." entries) */
1109 	memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME);
1110 	memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME);
1111 	de->attr = de[1].attr = ATTR_DIR;
1112 	de[0].lcase = de[1].lcase = 0;
1113 	de[0].time = de[1].time = time;
1114 	de[0].date = de[1].date = date;
1115 	de[0].ctime_cs = de[1].ctime_cs = 0;
1116 	if (sbi->options.isvfat) {
1117 		/* extra timestamps */
1118 		de[0].ctime = de[1].ctime = time;
1119 		de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date;
1120 	} else {
1121 		de[0].ctime = de[1].ctime = 0;
1122 		de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0;
1123 	}
1124 	de[0].start = cpu_to_le16(cluster);
1125 	de[0].starthi = cpu_to_le16(cluster >> 16);
1126 	de[1].start = cpu_to_le16(MSDOS_I(dir)->i_logstart);
1127 	de[1].starthi = cpu_to_le16(MSDOS_I(dir)->i_logstart >> 16);
1128 	de[0].size = de[1].size = 0;
1129 	memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));
1130 	set_buffer_uptodate(bhs[0]);
1131 	mark_buffer_dirty(bhs[0]);
1132 
1133 	err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE);
1134 	if (err)
1135 		goto error_free;
1136 
1137 	return cluster;
1138 
1139 error_free:
1140 	fat_free_clusters(dir, cluster);
1141 error:
1142 	return err;
1143 }
1144 
1145 EXPORT_SYMBOL_GPL(fat_alloc_new_dir);
1146 
1147 static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,
1148 			       int *nr_cluster, struct msdos_dir_entry **de,
1149 			       struct buffer_head **bh, loff_t *i_pos)
1150 {
1151 	struct super_block *sb = dir->i_sb;
1152 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
1153 	struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1154 	sector_t blknr, start_blknr, last_blknr;
1155 	unsigned long size, copy;
1156 	int err, i, n, offset, cluster[2];
1157 
1158 	/*
1159 	 * The minimum cluster size is 512bytes, and maximum entry
1160 	 * size is 32*slots (672bytes).  So, iff the cluster size is
1161 	 * 512bytes, we may need two clusters.
1162 	 */
1163 	size = nr_slots * sizeof(struct msdos_dir_entry);
1164 	*nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits;
1165 	BUG_ON(*nr_cluster > 2);
1166 
1167 	err = fat_alloc_clusters(dir, cluster, *nr_cluster);
1168 	if (err)
1169 		goto error;
1170 
1171 	/*
1172 	 * First stage: Fill the directory entry.  NOTE: This cluster
1173 	 * is not referenced from any inode yet, so updates order is
1174 	 * not important.
1175 	 */
1176 	i = n = copy = 0;
1177 	do {
1178 		start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]);
1179 		last_blknr = start_blknr + sbi->sec_per_clus;
1180 		while (blknr < last_blknr) {
1181 			bhs[n] = sb_getblk(sb, blknr);
1182 			if (!bhs[n]) {
1183 				err = -ENOMEM;
1184 				goto error_nomem;
1185 			}
1186 
1187 			/* fill the directory entry */
1188 			copy = min(size, sb->s_blocksize);
1189 			memcpy(bhs[n]->b_data, slots, copy);
1190 			slots += copy;
1191 			size -= copy;
1192 			set_buffer_uptodate(bhs[n]);
1193 			mark_buffer_dirty(bhs[n]);
1194 			if (!size)
1195 				break;
1196 			n++;
1197 			blknr++;
1198 		}
1199 	} while (++i < *nr_cluster);
1200 
1201 	memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy);
1202 	offset = copy - sizeof(struct msdos_dir_entry);
1203 	get_bh(bhs[n]);
1204 	*bh = bhs[n];
1205 	*de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
1206 	*i_pos = fat_make_i_pos(sb, *bh, *de);
1207 
1208 	/* Second stage: clear the rest of cluster, and write outs */
1209 	err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE);
1210 	if (err)
1211 		goto error_free;
1212 
1213 	return cluster[0];
1214 
1215 error_free:
1216 	brelse(*bh);
1217 	*bh = NULL;
1218 	n = 0;
1219 error_nomem:
1220 	for (i = 0; i < n; i++)
1221 		bforget(bhs[i]);
1222 	fat_free_clusters(dir, cluster[0]);
1223 error:
1224 	return err;
1225 }
1226 
1227 int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
1228 		    struct fat_slot_info *sinfo)
1229 {
1230 	struct super_block *sb = dir->i_sb;
1231 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
1232 	struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */
1233 	struct msdos_dir_entry *de;
1234 	int err, free_slots, i, nr_bhs;
1235 	loff_t pos, i_pos;
1236 
1237 	sinfo->nr_slots = nr_slots;
1238 
1239 	/* First stage: search free direcotry entries */
1240 	free_slots = nr_bhs = 0;
1241 	bh = prev = NULL;
1242 	pos = 0;
1243 	err = -ENOSPC;
1244 	while (fat_get_entry(dir, &pos, &bh, &de) > -1) {
1245 		/* check the maximum size of directory */
1246 		if (pos >= FAT_MAX_DIR_SIZE)
1247 			goto error;
1248 
1249 		if (IS_FREE(de->name)) {
1250 			if (prev != bh) {
1251 				get_bh(bh);
1252 				bhs[nr_bhs] = prev = bh;
1253 				nr_bhs++;
1254 			}
1255 			free_slots++;
1256 			if (free_slots == nr_slots)
1257 				goto found;
1258 		} else {
1259 			for (i = 0; i < nr_bhs; i++)
1260 				brelse(bhs[i]);
1261 			prev = NULL;
1262 			free_slots = nr_bhs = 0;
1263 		}
1264 	}
1265 	if (dir->i_ino == MSDOS_ROOT_INO) {
1266 		if (sbi->fat_bits != 32)
1267 			goto error;
1268 	} else if (MSDOS_I(dir)->i_start == 0) {
1269 		printk(KERN_ERR "FAT: Corrupted directory (i_pos %lld)\n",
1270 		       MSDOS_I(dir)->i_pos);
1271 		err = -EIO;
1272 		goto error;
1273 	}
1274 
1275 found:
1276 	err = 0;
1277 	pos -= free_slots * sizeof(*de);
1278 	nr_slots -= free_slots;
1279 	if (free_slots) {
1280 		/*
1281 		 * Second stage: filling the free entries with new entries.
1282 		 * NOTE: If this slots has shortname, first, we write
1283 		 * the long name slots, then write the short name.
1284 		 */
1285 		int size = free_slots * sizeof(*de);
1286 		int offset = pos & (sb->s_blocksize - 1);
1287 		int long_bhs = nr_bhs - (nr_slots == 0);
1288 
1289 		/* Fill the long name slots. */
1290 		for (i = 0; i < long_bhs; i++) {
1291 			int copy = min_t(int, sb->s_blocksize - offset, size);
1292 			memcpy(bhs[i]->b_data + offset, slots, copy);
1293 			mark_buffer_dirty(bhs[i]);
1294 			offset = 0;
1295 			slots += copy;
1296 			size -= copy;
1297 		}
1298 		if (long_bhs && IS_DIRSYNC(dir))
1299 			err = fat_sync_bhs(bhs, long_bhs);
1300 		if (!err && i < nr_bhs) {
1301 			/* Fill the short name slot. */
1302 			int copy = min_t(int, sb->s_blocksize - offset, size);
1303 			memcpy(bhs[i]->b_data + offset, slots, copy);
1304 			mark_buffer_dirty(bhs[i]);
1305 			if (IS_DIRSYNC(dir))
1306 				err = sync_dirty_buffer(bhs[i]);
1307 		}
1308 		for (i = 0; i < nr_bhs; i++)
1309 			brelse(bhs[i]);
1310 		if (err)
1311 			goto error_remove;
1312 	}
1313 
1314 	if (nr_slots) {
1315 		int cluster, nr_cluster;
1316 
1317 		/*
1318 		 * Third stage: allocate the cluster for new entries.
1319 		 * And initialize the cluster with new entries, then
1320 		 * add the cluster to dir.
1321 		 */
1322 		cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster,
1323 					      &de, &bh, &i_pos);
1324 		if (cluster < 0) {
1325 			err = cluster;
1326 			goto error_remove;
1327 		}
1328 		err = fat_chain_add(dir, cluster, nr_cluster);
1329 		if (err) {
1330 			fat_free_clusters(dir, cluster);
1331 			goto error_remove;
1332 		}
1333 		if (dir->i_size & (sbi->cluster_size - 1)) {
1334 			fat_fs_panic(sb, "Odd directory size");
1335 			dir->i_size = (dir->i_size + sbi->cluster_size - 1)
1336 				& ~((loff_t)sbi->cluster_size - 1);
1337 		}
1338 		dir->i_size += nr_cluster << sbi->cluster_bits;
1339 		MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits;
1340 	}
1341 	sinfo->slot_off = pos;
1342 	sinfo->de = de;
1343 	sinfo->bh = bh;
1344 	sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
1345 
1346 	return 0;
1347 
1348 error:
1349 	brelse(bh);
1350 	for (i = 0; i < nr_bhs; i++)
1351 		brelse(bhs[i]);
1352 	return err;
1353 
1354 error_remove:
1355 	brelse(bh);
1356 	if (free_slots)
1357 		__fat_remove_entries(dir, pos, free_slots);
1358 	return err;
1359 }
1360 
1361 EXPORT_SYMBOL_GPL(fat_add_entries);
1362