xref: /openbmc/linux/fs/fat/dir.c (revision 84764a41)
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/buffer_head.h>
20 #include <linux/compat.h>
21 #include <linux/uaccess.h>
22 #include <linux/kernel.h>
23 #include "fat.h"
24 
25 /*
26  * Maximum buffer size of short name.
27  * [(MSDOS_NAME + '.') * max one char + nul]
28  * For msdos style, ['.' (hidden) + MSDOS_NAME + '.' + nul]
29  */
30 #define FAT_MAX_SHORT_SIZE	((MSDOS_NAME + 1) * NLS_MAX_CHARSET_SIZE + 1)
31 /*
32  * Maximum buffer size of unicode chars from slots.
33  * [(max longname slots * 13 (size in a slot) + nul) * sizeof(wchar_t)]
34  */
35 #define FAT_MAX_UNI_CHARS	((MSDOS_SLOTS - 1) * 13 + 1)
36 #define FAT_MAX_UNI_SIZE	(FAT_MAX_UNI_CHARS * sizeof(wchar_t))
37 
38 static inline unsigned char fat_tolower(unsigned char c)
39 {
40 	return ((c >= 'A') && (c <= 'Z')) ? c+32 : c;
41 }
42 
43 static inline loff_t fat_make_i_pos(struct super_block *sb,
44 				    struct buffer_head *bh,
45 				    struct msdos_dir_entry *de)
46 {
47 	return ((loff_t)bh->b_blocknr << MSDOS_SB(sb)->dir_per_block_bits)
48 		| (de - (struct msdos_dir_entry *)bh->b_data);
49 }
50 
51 static inline void fat_dir_readahead(struct inode *dir, sector_t iblock,
52 				     sector_t phys)
53 {
54 	struct super_block *sb = dir->i_sb;
55 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
56 	struct buffer_head *bh;
57 	int sec;
58 
59 	/* This is not a first sector of cluster, or sec_per_clus == 1 */
60 	if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1)
61 		return;
62 	/* root dir of FAT12/FAT16 */
63 	if ((sbi->fat_bits != 32) && (dir->i_ino == MSDOS_ROOT_INO))
64 		return;
65 
66 	bh = sb_find_get_block(sb, phys);
67 	if (bh == NULL || !buffer_uptodate(bh)) {
68 		for (sec = 0; sec < sbi->sec_per_clus; sec++)
69 			sb_breadahead(sb, phys + sec);
70 	}
71 	brelse(bh);
72 }
73 
74 /* Returns the inode number of the directory entry at offset pos. If bh is
75    non-NULL, it is brelse'd before. Pos is incremented. The buffer header is
76    returned in bh.
77    AV. Most often we do it item-by-item. Makes sense to optimize.
78    AV. OK, there we go: if both bh and de are non-NULL we assume that we just
79    AV. want the next entry (took one explicit de=NULL in vfat/namei.c).
80    AV. It's done in fat_get_entry() (inlined), here the slow case lives.
81    AV. Additionally, when we return -1 (i.e. reached the end of directory)
82    AV. we make bh NULL.
83  */
84 static int fat__get_entry(struct inode *dir, loff_t *pos,
85 			  struct buffer_head **bh, struct msdos_dir_entry **de)
86 {
87 	struct super_block *sb = dir->i_sb;
88 	sector_t phys, iblock;
89 	unsigned long mapped_blocks;
90 	int err, offset;
91 
92 next:
93 	if (*bh)
94 		brelse(*bh);
95 
96 	*bh = NULL;
97 	iblock = *pos >> sb->s_blocksize_bits;
98 	err = fat_bmap(dir, iblock, &phys, &mapped_blocks, 0);
99 	if (err || !phys)
100 		return -1;	/* beyond EOF or error */
101 
102 	fat_dir_readahead(dir, iblock, phys);
103 
104 	*bh = sb_bread(sb, phys);
105 	if (*bh == NULL) {
106 		fat_msg_ratelimit(sb, KERN_ERR,
107 			"Directory bread(block %llu) failed", (llu)phys);
108 		/* skip this block */
109 		*pos = (iblock + 1) << sb->s_blocksize_bits;
110 		goto next;
111 	}
112 
113 	offset = *pos & (sb->s_blocksize - 1);
114 	*pos += sizeof(struct msdos_dir_entry);
115 	*de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
116 
117 	return 0;
118 }
119 
120 static inline int fat_get_entry(struct inode *dir, loff_t *pos,
121 				struct buffer_head **bh,
122 				struct msdos_dir_entry **de)
123 {
124 	/* Fast stuff first */
125 	if (*bh && *de &&
126 	   (*de - (struct msdos_dir_entry *)(*bh)->b_data) <
127 				MSDOS_SB(dir->i_sb)->dir_per_block - 1) {
128 		*pos += sizeof(struct msdos_dir_entry);
129 		(*de)++;
130 		return 0;
131 	}
132 	return fat__get_entry(dir, pos, bh, de);
133 }
134 
135 /*
136  * Convert Unicode 16 to UTF-8, translated Unicode, or ASCII.
137  * If uni_xlate is enabled and we can't get a 1:1 conversion, use a
138  * colon as an escape character since it is normally invalid on the vfat
139  * filesystem. The following four characters are the hexadecimal digits
140  * of Unicode value. This lets us do a full dump and restore of Unicode
141  * filenames. We could get into some trouble with long Unicode names,
142  * but ignore that right now.
143  * Ahem... Stack smashing in ring 0 isn't fun. Fixed.
144  */
145 static int uni16_to_x8(struct super_block *sb, unsigned char *ascii,
146 		       const wchar_t *uni, int len, struct nls_table *nls)
147 {
148 	int uni_xlate = MSDOS_SB(sb)->options.unicode_xlate;
149 	const wchar_t *ip;
150 	wchar_t ec;
151 	unsigned char *op;
152 	int charlen;
153 
154 	ip = uni;
155 	op = ascii;
156 
157 	while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {
158 		ec = *ip++;
159 		charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE);
160 		if (charlen > 0) {
161 			op += charlen;
162 			len -= charlen;
163 		} else {
164 			if (uni_xlate == 1) {
165 				*op++ = ':';
166 				op = hex_byte_pack(op, ec >> 8);
167 				op = hex_byte_pack(op, ec);
168 				len -= 5;
169 			} else {
170 				*op++ = '?';
171 				len--;
172 			}
173 		}
174 	}
175 
176 	if (unlikely(*ip)) {
177 		fat_msg(sb, KERN_WARNING,
178 			"filename was truncated while converting.");
179 	}
180 
181 	*op = 0;
182 	return op - ascii;
183 }
184 
185 static inline int fat_uni_to_x8(struct super_block *sb, const wchar_t *uni,
186 				unsigned char *buf, int size)
187 {
188 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
189 	if (sbi->options.utf8)
190 		return utf16s_to_utf8s(uni, FAT_MAX_UNI_CHARS,
191 				UTF16_HOST_ENDIAN, buf, size);
192 	else
193 		return uni16_to_x8(sb, buf, uni, size, sbi->nls_io);
194 }
195 
196 static inline int
197 fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
198 {
199 	int charlen;
200 
201 	charlen = t->char2uni(c, clen, uni);
202 	if (charlen < 0) {
203 		*uni = 0x003f;	/* a question mark */
204 		charlen = 1;
205 	}
206 	return charlen;
207 }
208 
209 static inline int
210 fat_short2lower_uni(struct nls_table *t, unsigned char *c,
211 		    int clen, wchar_t *uni)
212 {
213 	int charlen;
214 	wchar_t wc;
215 
216 	charlen = t->char2uni(c, clen, &wc);
217 	if (charlen < 0) {
218 		*uni = 0x003f;	/* a question mark */
219 		charlen = 1;
220 	} else if (charlen <= 1) {
221 		unsigned char nc = t->charset2lower[*c];
222 
223 		if (!nc)
224 			nc = *c;
225 
226 		charlen = t->char2uni(&nc, 1, uni);
227 		if (charlen < 0) {
228 			*uni = 0x003f;	/* a question mark */
229 			charlen = 1;
230 		}
231 	} else
232 		*uni = wc;
233 
234 	return charlen;
235 }
236 
237 static inline int
238 fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size,
239 		  wchar_t *uni_buf, unsigned short opt, int lower)
240 {
241 	int len = 0;
242 
243 	if (opt & VFAT_SFN_DISPLAY_LOWER)
244 		len =  fat_short2lower_uni(nls, buf, buf_size, uni_buf);
245 	else if (opt & VFAT_SFN_DISPLAY_WIN95)
246 		len = fat_short2uni(nls, buf, buf_size, uni_buf);
247 	else if (opt & VFAT_SFN_DISPLAY_WINNT) {
248 		if (lower)
249 			len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
250 		else
251 			len = fat_short2uni(nls, buf, buf_size, uni_buf);
252 	} else
253 		len = fat_short2uni(nls, buf, buf_size, uni_buf);
254 
255 	return len;
256 }
257 
258 static inline int fat_name_match(struct msdos_sb_info *sbi,
259 				 const unsigned char *a, int a_len,
260 				 const unsigned char *b, int b_len)
261 {
262 	if (a_len != b_len)
263 		return 0;
264 
265 	if (sbi->options.name_check != 's')
266 		return !nls_strnicmp(sbi->nls_io, a, b, a_len);
267 	else
268 		return !memcmp(a, b, a_len);
269 }
270 
271 enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, };
272 
273 /**
274  * fat_parse_long - Parse extended directory entry.
275  *
276  * This function returns zero on success, negative value on error, or one of
277  * the following:
278  *
279  * %PARSE_INVALID - Directory entry is invalid.
280  * %PARSE_NOT_LONGNAME - Directory entry does not contain longname.
281  * %PARSE_EOF - Directory has no more entries.
282  */
283 static int fat_parse_long(struct inode *dir, loff_t *pos,
284 			  struct buffer_head **bh, struct msdos_dir_entry **de,
285 			  wchar_t **unicode, unsigned char *nr_slots)
286 {
287 	struct msdos_dir_slot *ds;
288 	unsigned char id, slot, slots, alias_checksum;
289 
290 	if (!*unicode) {
291 		*unicode = __getname();
292 		if (!*unicode) {
293 			brelse(*bh);
294 			return -ENOMEM;
295 		}
296 	}
297 parse_long:
298 	slots = 0;
299 	ds = (struct msdos_dir_slot *)*de;
300 	id = ds->id;
301 	if (!(id & 0x40))
302 		return PARSE_INVALID;
303 	slots = id & ~0x40;
304 	if (slots > 20 || !slots)	/* ceil(256 * 2 / 26) */
305 		return PARSE_INVALID;
306 	*nr_slots = slots;
307 	alias_checksum = ds->alias_checksum;
308 
309 	slot = slots;
310 	while (1) {
311 		int offset;
312 
313 		slot--;
314 		offset = slot * 13;
315 		fat16_towchar(*unicode + offset, ds->name0_4, 5);
316 		fat16_towchar(*unicode + offset + 5, ds->name5_10, 6);
317 		fat16_towchar(*unicode + offset + 11, ds->name11_12, 2);
318 
319 		if (ds->id & 0x40)
320 			(*unicode)[offset + 13] = 0;
321 		if (fat_get_entry(dir, pos, bh, de) < 0)
322 			return PARSE_EOF;
323 		if (slot == 0)
324 			break;
325 		ds = (struct msdos_dir_slot *)*de;
326 		if (ds->attr != ATTR_EXT)
327 			return PARSE_NOT_LONGNAME;
328 		if ((ds->id & ~0x40) != slot)
329 			goto parse_long;
330 		if (ds->alias_checksum != alias_checksum)
331 			goto parse_long;
332 	}
333 	if ((*de)->name[0] == DELETED_FLAG)
334 		return PARSE_INVALID;
335 	if ((*de)->attr == ATTR_EXT)
336 		goto parse_long;
337 	if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME))
338 		return PARSE_INVALID;
339 	if (fat_checksum((*de)->name) != alias_checksum)
340 		*nr_slots = 0;
341 
342 	return 0;
343 }
344 
345 /**
346  * fat_parse_short - Parse MS-DOS (short) directory entry.
347  * @sb:		superblock
348  * @de:		directory entry to parse
349  * @name:	FAT_MAX_SHORT_SIZE array in which to place extracted name
350  * @dot_hidden:	Nonzero == prepend '.' to names with ATTR_HIDDEN
351  *
352  * Returns the number of characters extracted into 'name'.
353  */
354 static int fat_parse_short(struct super_block *sb,
355 			   const struct msdos_dir_entry *de,
356 			   unsigned char *name, int dot_hidden)
357 {
358 	const struct msdos_sb_info *sbi = MSDOS_SB(sb);
359 	int isvfat = sbi->options.isvfat;
360 	int nocase = sbi->options.nocase;
361 	unsigned short opt_shortname = sbi->options.shortname;
362 	struct nls_table *nls_disk = sbi->nls_disk;
363 	wchar_t uni_name[14];
364 	unsigned char c, work[MSDOS_NAME];
365 	unsigned char *ptname = name;
366 	int chi, chl, i, j, k;
367 	int dotoffset = 0;
368 	int name_len = 0, uni_len = 0;
369 
370 	if (!isvfat && dot_hidden && (de->attr & ATTR_HIDDEN)) {
371 		*ptname++ = '.';
372 		dotoffset = 1;
373 	}
374 
375 	memcpy(work, de->name, sizeof(work));
376 	/* see namei.c, msdos_format_name */
377 	if (work[0] == 0x05)
378 		work[0] = 0xE5;
379 
380 	/* Filename */
381 	for (i = 0, j = 0; i < 8;) {
382 		c = work[i];
383 		if (!c)
384 			break;
385 		chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
386 					&uni_name[j++], opt_shortname,
387 					de->lcase & CASE_LOWER_BASE);
388 		if (chl <= 1) {
389 			if (!isvfat)
390 				ptname[i] = nocase ? c : fat_tolower(c);
391 			i++;
392 			if (c != ' ') {
393 				name_len = i;
394 				uni_len  = j;
395 			}
396 		} else {
397 			uni_len = j;
398 			if (isvfat)
399 				i += min(chl, 8-i);
400 			else {
401 				for (chi = 0; chi < chl && i < 8; chi++, i++)
402 					ptname[i] = work[i];
403 			}
404 			if (chl)
405 				name_len = i;
406 		}
407 	}
408 
409 	i = name_len;
410 	j = uni_len;
411 	fat_short2uni(nls_disk, ".", 1, &uni_name[j++]);
412 	if (!isvfat)
413 		ptname[i] = '.';
414 	i++;
415 
416 	/* Extension */
417 	for (k = 8; k < MSDOS_NAME;) {
418 		c = work[k];
419 		if (!c)
420 			break;
421 		chl = fat_shortname2uni(nls_disk, &work[k], MSDOS_NAME - k,
422 					&uni_name[j++], opt_shortname,
423 					de->lcase & CASE_LOWER_EXT);
424 		if (chl <= 1) {
425 			k++;
426 			if (!isvfat)
427 				ptname[i] = nocase ? c : fat_tolower(c);
428 			i++;
429 			if (c != ' ') {
430 				name_len = i;
431 				uni_len  = j;
432 			}
433 		} else {
434 			uni_len = j;
435 			if (isvfat) {
436 				int offset = min(chl, MSDOS_NAME-k);
437 				k += offset;
438 				i += offset;
439 			} else {
440 				for (chi = 0; chi < chl && k < MSDOS_NAME;
441 				     chi++, i++, k++) {
442 						ptname[i] = work[k];
443 				}
444 			}
445 			if (chl)
446 				name_len = i;
447 		}
448 	}
449 
450 	if (name_len > 0) {
451 		name_len += dotoffset;
452 
453 		if (sbi->options.isvfat) {
454 			uni_name[uni_len] = 0x0000;
455 			name_len = fat_uni_to_x8(sb, uni_name, name,
456 						 FAT_MAX_SHORT_SIZE);
457 		}
458 	}
459 
460 	return name_len;
461 }
462 
463 /*
464  * Return values: negative -> error, 0 -> not found, positive -> found,
465  * value is the total amount of slots, including the shortname entry.
466  */
467 int fat_search_long(struct inode *inode, const unsigned char *name,
468 		    int name_len, struct fat_slot_info *sinfo)
469 {
470 	struct super_block *sb = inode->i_sb;
471 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
472 	struct buffer_head *bh = NULL;
473 	struct msdos_dir_entry *de;
474 	unsigned char nr_slots;
475 	wchar_t *unicode = NULL;
476 	unsigned char bufname[FAT_MAX_SHORT_SIZE];
477 	loff_t cpos = 0;
478 	int err, len;
479 
480 	err = -ENOENT;
481 	while (1) {
482 		if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
483 			goto end_of_dir;
484 parse_record:
485 		nr_slots = 0;
486 		if (de->name[0] == DELETED_FLAG)
487 			continue;
488 		if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
489 			continue;
490 		if (de->attr != ATTR_EXT && IS_FREE(de->name))
491 			continue;
492 		if (de->attr == ATTR_EXT) {
493 			int status = fat_parse_long(inode, &cpos, &bh, &de,
494 						    &unicode, &nr_slots);
495 			if (status < 0) {
496 				err = status;
497 				goto end_of_dir;
498 			} else if (status == PARSE_INVALID)
499 				continue;
500 			else if (status == PARSE_NOT_LONGNAME)
501 				goto parse_record;
502 			else if (status == PARSE_EOF)
503 				goto end_of_dir;
504 		}
505 
506 		/* Never prepend '.' to hidden files here.
507 		 * That is done only for msdos mounts (and only when
508 		 * 'dotsOK=yes'); if we are executing here, it is in the
509 		 * context of a vfat mount.
510 		 */
511 		len = fat_parse_short(sb, de, bufname, 0);
512 		if (len == 0)
513 			continue;
514 
515 		/* Compare shortname */
516 		if (fat_name_match(sbi, name, name_len, bufname, len))
517 			goto found;
518 
519 		if (nr_slots) {
520 			void *longname = unicode + FAT_MAX_UNI_CHARS;
521 			int size = PATH_MAX - FAT_MAX_UNI_SIZE;
522 
523 			/* Compare longname */
524 			len = fat_uni_to_x8(sb, unicode, longname, size);
525 			if (fat_name_match(sbi, name, name_len, longname, len))
526 				goto found;
527 		}
528 	}
529 
530 found:
531 	nr_slots++;	/* include the de */
532 	sinfo->slot_off = cpos - nr_slots * sizeof(*de);
533 	sinfo->nr_slots = nr_slots;
534 	sinfo->de = de;
535 	sinfo->bh = bh;
536 	sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
537 	err = 0;
538 end_of_dir:
539 	if (unicode)
540 		__putname(unicode);
541 
542 	return err;
543 }
544 EXPORT_SYMBOL_GPL(fat_search_long);
545 
546 struct fat_ioctl_filldir_callback {
547 	void __user *dirent;
548 	int result;
549 	/* for dir ioctl */
550 	const char *longname;
551 	int long_len;
552 	const char *shortname;
553 	int short_len;
554 };
555 
556 static int __fat_readdir(struct inode *inode, struct file *filp, void *dirent,
557 			 filldir_t filldir, int short_only, int both)
558 {
559 	struct super_block *sb = inode->i_sb;
560 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
561 	struct buffer_head *bh;
562 	struct msdos_dir_entry *de;
563 	unsigned char nr_slots;
564 	wchar_t *unicode = NULL;
565 	unsigned char bufname[FAT_MAX_SHORT_SIZE];
566 	int isvfat = sbi->options.isvfat;
567 	const char *fill_name = NULL;
568 	unsigned long inum;
569 	unsigned long lpos, dummy, *furrfu = &lpos;
570 	loff_t cpos;
571 	int short_len = 0, fill_len = 0;
572 	int ret = 0;
573 
574 	mutex_lock(&sbi->s_lock);
575 
576 	cpos = filp->f_pos;
577 	/* Fake . and .. for the root directory. */
578 	if (inode->i_ino == MSDOS_ROOT_INO) {
579 		while (cpos < 2) {
580 			if (filldir(dirent, "..", cpos+1, cpos,
581 				    MSDOS_ROOT_INO, DT_DIR) < 0)
582 				goto out;
583 			cpos++;
584 			filp->f_pos++;
585 		}
586 		if (cpos == 2) {
587 			dummy = 2;
588 			furrfu = &dummy;
589 			cpos = 0;
590 		}
591 	}
592 	if (cpos & (sizeof(struct msdos_dir_entry) - 1)) {
593 		ret = -ENOENT;
594 		goto out;
595 	}
596 
597 	bh = NULL;
598 get_new:
599 	if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
600 		goto end_of_dir;
601 parse_record:
602 	nr_slots = 0;
603 	/*
604 	 * Check for long filename entry, but if short_only, we don't
605 	 * need to parse long filename.
606 	 */
607 	if (isvfat && !short_only) {
608 		if (de->name[0] == DELETED_FLAG)
609 			goto record_end;
610 		if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
611 			goto record_end;
612 		if (de->attr != ATTR_EXT && IS_FREE(de->name))
613 			goto record_end;
614 	} else {
615 		if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))
616 			goto record_end;
617 	}
618 
619 	if (isvfat && de->attr == ATTR_EXT) {
620 		int status = fat_parse_long(inode, &cpos, &bh, &de,
621 					    &unicode, &nr_slots);
622 		if (status < 0) {
623 			filp->f_pos = cpos;
624 			ret = status;
625 			goto out;
626 		} else if (status == PARSE_INVALID)
627 			goto record_end;
628 		else if (status == PARSE_NOT_LONGNAME)
629 			goto parse_record;
630 		else if (status == PARSE_EOF)
631 			goto end_of_dir;
632 
633 		if (nr_slots) {
634 			void *longname = unicode + FAT_MAX_UNI_CHARS;
635 			int size = PATH_MAX - FAT_MAX_UNI_SIZE;
636 			int len = fat_uni_to_x8(sb, unicode, longname, size);
637 
638 			fill_name = longname;
639 			fill_len = len;
640 			/* !both && !short_only, so we don't need shortname. */
641 			if (!both)
642 				goto start_filldir;
643 		}
644 	}
645 
646 	short_len = fat_parse_short(sb, de, bufname, sbi->options.dotsOK);
647 	if (short_len == 0)
648 		goto record_end;
649 
650 	if (nr_slots) {
651 		/* hack for fat_ioctl_filldir() */
652 		struct fat_ioctl_filldir_callback *p = dirent;
653 
654 		p->longname = fill_name;
655 		p->long_len = fill_len;
656 		p->shortname = bufname;
657 		p->short_len = short_len;
658 		fill_name = NULL;
659 		fill_len = 0;
660 	} else {
661 		fill_name = bufname;
662 		fill_len = short_len;
663 	}
664 
665 start_filldir:
666 	lpos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
667 	if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME))
668 		inum = inode->i_ino;
669 	else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
670 		inum = parent_ino(filp->f_path.dentry);
671 	} else {
672 		loff_t i_pos = fat_make_i_pos(sb, bh, de);
673 		struct inode *tmp = fat_iget(sb, i_pos);
674 		if (tmp) {
675 			inum = tmp->i_ino;
676 			iput(tmp);
677 		} else
678 			inum = iunique(sb, MSDOS_ROOT_INO);
679 	}
680 
681 	if (filldir(dirent, fill_name, fill_len, *furrfu, inum,
682 		    (de->attr & ATTR_DIR) ? DT_DIR : DT_REG) < 0)
683 		goto fill_failed;
684 
685 record_end:
686 	furrfu = &lpos;
687 	filp->f_pos = cpos;
688 	goto get_new;
689 end_of_dir:
690 	filp->f_pos = cpos;
691 fill_failed:
692 	brelse(bh);
693 	if (unicode)
694 		__putname(unicode);
695 out:
696 	mutex_unlock(&sbi->s_lock);
697 	return ret;
698 }
699 
700 static int fat_readdir(struct file *filp, void *dirent, filldir_t filldir)
701 {
702 	struct inode *inode = filp->f_path.dentry->d_inode;
703 	return __fat_readdir(inode, filp, dirent, filldir, 0, 0);
704 }
705 
706 #define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type)			   \
707 static int func(void *__buf, const char *name, int name_len,		   \
708 			     loff_t offset, u64 ino, unsigned int d_type)  \
709 {									   \
710 	struct fat_ioctl_filldir_callback *buf = __buf;			   \
711 	struct dirent_type __user *d1 = buf->dirent;			   \
712 	struct dirent_type __user *d2 = d1 + 1;				   \
713 									   \
714 	if (buf->result)						   \
715 		return -EINVAL;						   \
716 	buf->result++;							   \
717 									   \
718 	if (name != NULL) {						   \
719 		/* dirent has only short name */			   \
720 		if (name_len >= sizeof(d1->d_name))			   \
721 			name_len = sizeof(d1->d_name) - 1;		   \
722 									   \
723 		if (put_user(0, d2->d_name)			||	   \
724 		    put_user(0, &d2->d_reclen)			||	   \
725 		    copy_to_user(d1->d_name, name, name_len)	||	   \
726 		    put_user(0, d1->d_name + name_len)		||	   \
727 		    put_user(name_len, &d1->d_reclen))			   \
728 			goto efault;					   \
729 	} else {							   \
730 		/* dirent has short and long name */			   \
731 		const char *longname = buf->longname;			   \
732 		int long_len = buf->long_len;				   \
733 		const char *shortname = buf->shortname;			   \
734 		int short_len = buf->short_len;				   \
735 									   \
736 		if (long_len >= sizeof(d1->d_name))			   \
737 			long_len = sizeof(d1->d_name) - 1;		   \
738 		if (short_len >= sizeof(d1->d_name))			   \
739 			short_len = sizeof(d1->d_name) - 1;		   \
740 									   \
741 		if (copy_to_user(d2->d_name, longname, long_len)	|| \
742 		    put_user(0, d2->d_name + long_len)			|| \
743 		    put_user(long_len, &d2->d_reclen)			|| \
744 		    put_user(ino, &d2->d_ino)				|| \
745 		    put_user(offset, &d2->d_off)			|| \
746 		    copy_to_user(d1->d_name, shortname, short_len)	|| \
747 		    put_user(0, d1->d_name + short_len)			|| \
748 		    put_user(short_len, &d1->d_reclen))			   \
749 			goto efault;					   \
750 	}								   \
751 	return 0;							   \
752 efault:									   \
753 	buf->result = -EFAULT;						   \
754 	return -EFAULT;							   \
755 }
756 
757 FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)
758 
759 static int fat_ioctl_readdir(struct inode *inode, struct file *filp,
760 			     void __user *dirent, filldir_t filldir,
761 			     int short_only, int both)
762 {
763 	struct fat_ioctl_filldir_callback buf;
764 	int ret;
765 
766 	buf.dirent = dirent;
767 	buf.result = 0;
768 	mutex_lock(&inode->i_mutex);
769 	ret = -ENOENT;
770 	if (!IS_DEADDIR(inode)) {
771 		ret = __fat_readdir(inode, filp, &buf, filldir,
772 				    short_only, both);
773 	}
774 	mutex_unlock(&inode->i_mutex);
775 	if (ret >= 0)
776 		ret = buf.result;
777 	return ret;
778 }
779 
780 static long fat_dir_ioctl(struct file *filp, unsigned int cmd,
781 			  unsigned long arg)
782 {
783 	struct inode *inode = filp->f_path.dentry->d_inode;
784 	struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg;
785 	int short_only, both;
786 
787 	switch (cmd) {
788 	case VFAT_IOCTL_READDIR_SHORT:
789 		short_only = 1;
790 		both = 0;
791 		break;
792 	case VFAT_IOCTL_READDIR_BOTH:
793 		short_only = 0;
794 		both = 1;
795 		break;
796 	default:
797 		return fat_generic_ioctl(filp, cmd, arg);
798 	}
799 
800 	if (!access_ok(VERIFY_WRITE, d1, sizeof(struct __fat_dirent[2])))
801 		return -EFAULT;
802 	/*
803 	 * Yes, we don't need this put_user() absolutely. However old
804 	 * code didn't return the right value. So, app use this value,
805 	 * in order to check whether it is EOF.
806 	 */
807 	if (put_user(0, &d1->d_reclen))
808 		return -EFAULT;
809 
810 	return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir,
811 				 short_only, both);
812 }
813 
814 #ifdef CONFIG_COMPAT
815 #define	VFAT_IOCTL_READDIR_BOTH32	_IOR('r', 1, struct compat_dirent[2])
816 #define	VFAT_IOCTL_READDIR_SHORT32	_IOR('r', 2, struct compat_dirent[2])
817 
818 FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent)
819 
820 static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd,
821 				 unsigned long arg)
822 {
823 	struct inode *inode = filp->f_path.dentry->d_inode;
824 	struct compat_dirent __user *d1 = compat_ptr(arg);
825 	int short_only, both;
826 
827 	switch (cmd) {
828 	case VFAT_IOCTL_READDIR_SHORT32:
829 		short_only = 1;
830 		both = 0;
831 		break;
832 	case VFAT_IOCTL_READDIR_BOTH32:
833 		short_only = 0;
834 		both = 1;
835 		break;
836 	default:
837 		return fat_generic_ioctl(filp, cmd, (unsigned long)arg);
838 	}
839 
840 	if (!access_ok(VERIFY_WRITE, d1, sizeof(struct compat_dirent[2])))
841 		return -EFAULT;
842 	/*
843 	 * Yes, we don't need this put_user() absolutely. However old
844 	 * code didn't return the right value. So, app use this value,
845 	 * in order to check whether it is EOF.
846 	 */
847 	if (put_user(0, &d1->d_reclen))
848 		return -EFAULT;
849 
850 	return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir,
851 				 short_only, both);
852 }
853 #endif /* CONFIG_COMPAT */
854 
855 const struct file_operations fat_dir_operations = {
856 	.llseek		= generic_file_llseek,
857 	.read		= generic_read_dir,
858 	.readdir	= fat_readdir,
859 	.unlocked_ioctl	= fat_dir_ioctl,
860 #ifdef CONFIG_COMPAT
861 	.compat_ioctl	= fat_compat_dir_ioctl,
862 #endif
863 	.fsync		= fat_file_fsync,
864 };
865 
866 static int fat_get_short_entry(struct inode *dir, loff_t *pos,
867 			       struct buffer_head **bh,
868 			       struct msdos_dir_entry **de)
869 {
870 	while (fat_get_entry(dir, pos, bh, de) >= 0) {
871 		/* free entry or long name entry or volume label */
872 		if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))
873 			return 0;
874 	}
875 	return -ENOENT;
876 }
877 
878 /*
879  * The ".." entry can not provide the "struct fat_slot_info" information
880  * for inode, nor a usable i_pos. So, this function provides some information
881  * only.
882  *
883  * Since this function walks through the on-disk inodes within a directory,
884  * callers are responsible for taking any locks necessary to prevent the
885  * directory from changing.
886  */
887 int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
888 			 struct msdos_dir_entry **de)
889 {
890 	loff_t offset = 0;
891 
892 	*de = NULL;
893 	while (fat_get_short_entry(dir, &offset, bh, de) >= 0) {
894 		if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME))
895 			return 0;
896 	}
897 	return -ENOENT;
898 }
899 EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);
900 
901 /* See if directory is empty */
902 int fat_dir_empty(struct inode *dir)
903 {
904 	struct buffer_head *bh;
905 	struct msdos_dir_entry *de;
906 	loff_t cpos;
907 	int result = 0;
908 
909 	bh = NULL;
910 	cpos = 0;
911 	while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
912 		if (strncmp(de->name, MSDOS_DOT   , MSDOS_NAME) &&
913 		    strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
914 			result = -ENOTEMPTY;
915 			break;
916 		}
917 	}
918 	brelse(bh);
919 	return result;
920 }
921 EXPORT_SYMBOL_GPL(fat_dir_empty);
922 
923 /*
924  * fat_subdirs counts the number of sub-directories of dir. It can be run
925  * on directories being created.
926  */
927 int fat_subdirs(struct inode *dir)
928 {
929 	struct buffer_head *bh;
930 	struct msdos_dir_entry *de;
931 	loff_t cpos;
932 	int count = 0;
933 
934 	bh = NULL;
935 	cpos = 0;
936 	while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
937 		if (de->attr & ATTR_DIR)
938 			count++;
939 	}
940 	brelse(bh);
941 	return count;
942 }
943 
944 /*
945  * Scans a directory for a given file (name points to its formatted name).
946  * Returns an error code or zero.
947  */
948 int fat_scan(struct inode *dir, const unsigned char *name,
949 	     struct fat_slot_info *sinfo)
950 {
951 	struct super_block *sb = dir->i_sb;
952 
953 	sinfo->slot_off = 0;
954 	sinfo->bh = NULL;
955 	while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
956 				   &sinfo->de) >= 0) {
957 		if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) {
958 			sinfo->slot_off -= sizeof(*sinfo->de);
959 			sinfo->nr_slots = 1;
960 			sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
961 			return 0;
962 		}
963 	}
964 	return -ENOENT;
965 }
966 EXPORT_SYMBOL_GPL(fat_scan);
967 
968 static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)
969 {
970 	struct super_block *sb = dir->i_sb;
971 	struct buffer_head *bh;
972 	struct msdos_dir_entry *de, *endp;
973 	int err = 0, orig_slots;
974 
975 	while (nr_slots) {
976 		bh = NULL;
977 		if (fat_get_entry(dir, &pos, &bh, &de) < 0) {
978 			err = -EIO;
979 			break;
980 		}
981 
982 		orig_slots = nr_slots;
983 		endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize);
984 		while (nr_slots && de < endp) {
985 			de->name[0] = DELETED_FLAG;
986 			de++;
987 			nr_slots--;
988 		}
989 		mark_buffer_dirty_inode(bh, dir);
990 		if (IS_DIRSYNC(dir))
991 			err = sync_dirty_buffer(bh);
992 		brelse(bh);
993 		if (err)
994 			break;
995 
996 		/* pos is *next* de's position, so this does `- sizeof(de)' */
997 		pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de);
998 	}
999 
1000 	return err;
1001 }
1002 
1003 int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)
1004 {
1005 	struct super_block *sb = dir->i_sb;
1006 	struct msdos_dir_entry *de;
1007 	struct buffer_head *bh;
1008 	int err = 0, nr_slots;
1009 
1010 	/*
1011 	 * First stage: Remove the shortname. By this, the directory
1012 	 * entry is removed.
1013 	 */
1014 	nr_slots = sinfo->nr_slots;
1015 	de = sinfo->de;
1016 	sinfo->de = NULL;
1017 	bh = sinfo->bh;
1018 	sinfo->bh = NULL;
1019 	while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) {
1020 		de->name[0] = DELETED_FLAG;
1021 		de--;
1022 		nr_slots--;
1023 	}
1024 	mark_buffer_dirty_inode(bh, dir);
1025 	if (IS_DIRSYNC(dir))
1026 		err = sync_dirty_buffer(bh);
1027 	brelse(bh);
1028 	if (err)
1029 		return err;
1030 	dir->i_version++;
1031 
1032 	if (nr_slots) {
1033 		/*
1034 		 * Second stage: remove the remaining longname slots.
1035 		 * (This directory entry is already removed, and so return
1036 		 * the success)
1037 		 */
1038 		err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots);
1039 		if (err) {
1040 			fat_msg(sb, KERN_WARNING,
1041 			       "Couldn't remove the long name slots");
1042 		}
1043 	}
1044 
1045 	dir->i_mtime = dir->i_atime = CURRENT_TIME_SEC;
1046 	if (IS_DIRSYNC(dir))
1047 		(void)fat_sync_inode(dir);
1048 	else
1049 		mark_inode_dirty(dir);
1050 
1051 	return 0;
1052 }
1053 EXPORT_SYMBOL_GPL(fat_remove_entries);
1054 
1055 static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,
1056 			      struct buffer_head **bhs, int nr_bhs)
1057 {
1058 	struct super_block *sb = dir->i_sb;
1059 	sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus;
1060 	int err, i, n;
1061 
1062 	/* Zeroing the unused blocks on this cluster */
1063 	blknr += nr_used;
1064 	n = nr_used;
1065 	while (blknr < last_blknr) {
1066 		bhs[n] = sb_getblk(sb, blknr);
1067 		if (!bhs[n]) {
1068 			err = -ENOMEM;
1069 			goto error;
1070 		}
1071 		memset(bhs[n]->b_data, 0, sb->s_blocksize);
1072 		set_buffer_uptodate(bhs[n]);
1073 		mark_buffer_dirty_inode(bhs[n], dir);
1074 
1075 		n++;
1076 		blknr++;
1077 		if (n == nr_bhs) {
1078 			if (IS_DIRSYNC(dir)) {
1079 				err = fat_sync_bhs(bhs, n);
1080 				if (err)
1081 					goto error;
1082 			}
1083 			for (i = 0; i < n; i++)
1084 				brelse(bhs[i]);
1085 			n = 0;
1086 		}
1087 	}
1088 	if (IS_DIRSYNC(dir)) {
1089 		err = fat_sync_bhs(bhs, n);
1090 		if (err)
1091 			goto error;
1092 	}
1093 	for (i = 0; i < n; i++)
1094 		brelse(bhs[i]);
1095 
1096 	return 0;
1097 
1098 error:
1099 	for (i = 0; i < n; i++)
1100 		bforget(bhs[i]);
1101 	return err;
1102 }
1103 
1104 int fat_alloc_new_dir(struct inode *dir, struct timespec *ts)
1105 {
1106 	struct super_block *sb = dir->i_sb;
1107 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
1108 	struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1109 	struct msdos_dir_entry *de;
1110 	sector_t blknr;
1111 	__le16 date, time;
1112 	u8 time_cs;
1113 	int err, cluster;
1114 
1115 	err = fat_alloc_clusters(dir, &cluster, 1);
1116 	if (err)
1117 		goto error;
1118 
1119 	blknr = fat_clus_to_blknr(sbi, cluster);
1120 	bhs[0] = sb_getblk(sb, blknr);
1121 	if (!bhs[0]) {
1122 		err = -ENOMEM;
1123 		goto error_free;
1124 	}
1125 
1126 	fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
1127 
1128 	de = (struct msdos_dir_entry *)bhs[0]->b_data;
1129 	/* filling the new directory slots ("." and ".." entries) */
1130 	memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME);
1131 	memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME);
1132 	de->attr = de[1].attr = ATTR_DIR;
1133 	de[0].lcase = de[1].lcase = 0;
1134 	de[0].time = de[1].time = time;
1135 	de[0].date = de[1].date = date;
1136 	if (sbi->options.isvfat) {
1137 		/* extra timestamps */
1138 		de[0].ctime = de[1].ctime = time;
1139 		de[0].ctime_cs = de[1].ctime_cs = time_cs;
1140 		de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date;
1141 	} else {
1142 		de[0].ctime = de[1].ctime = 0;
1143 		de[0].ctime_cs = de[1].ctime_cs = 0;
1144 		de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0;
1145 	}
1146 	fat_set_start(&de[0], cluster);
1147 	fat_set_start(&de[1], MSDOS_I(dir)->i_logstart);
1148 	de[0].size = de[1].size = 0;
1149 	memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));
1150 	set_buffer_uptodate(bhs[0]);
1151 	mark_buffer_dirty_inode(bhs[0], dir);
1152 
1153 	err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE);
1154 	if (err)
1155 		goto error_free;
1156 
1157 	return cluster;
1158 
1159 error_free:
1160 	fat_free_clusters(dir, cluster);
1161 error:
1162 	return err;
1163 }
1164 EXPORT_SYMBOL_GPL(fat_alloc_new_dir);
1165 
1166 static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,
1167 			       int *nr_cluster, struct msdos_dir_entry **de,
1168 			       struct buffer_head **bh, loff_t *i_pos)
1169 {
1170 	struct super_block *sb = dir->i_sb;
1171 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
1172 	struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1173 	sector_t blknr, start_blknr, last_blknr;
1174 	unsigned long size, copy;
1175 	int err, i, n, offset, cluster[2];
1176 
1177 	/*
1178 	 * The minimum cluster size is 512bytes, and maximum entry
1179 	 * size is 32*slots (672bytes).  So, iff the cluster size is
1180 	 * 512bytes, we may need two clusters.
1181 	 */
1182 	size = nr_slots * sizeof(struct msdos_dir_entry);
1183 	*nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits;
1184 	BUG_ON(*nr_cluster > 2);
1185 
1186 	err = fat_alloc_clusters(dir, cluster, *nr_cluster);
1187 	if (err)
1188 		goto error;
1189 
1190 	/*
1191 	 * First stage: Fill the directory entry.  NOTE: This cluster
1192 	 * is not referenced from any inode yet, so updates order is
1193 	 * not important.
1194 	 */
1195 	i = n = copy = 0;
1196 	do {
1197 		start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]);
1198 		last_blknr = start_blknr + sbi->sec_per_clus;
1199 		while (blknr < last_blknr) {
1200 			bhs[n] = sb_getblk(sb, blknr);
1201 			if (!bhs[n]) {
1202 				err = -ENOMEM;
1203 				goto error_nomem;
1204 			}
1205 
1206 			/* fill the directory entry */
1207 			copy = min(size, sb->s_blocksize);
1208 			memcpy(bhs[n]->b_data, slots, copy);
1209 			slots += copy;
1210 			size -= copy;
1211 			set_buffer_uptodate(bhs[n]);
1212 			mark_buffer_dirty_inode(bhs[n], dir);
1213 			if (!size)
1214 				break;
1215 			n++;
1216 			blknr++;
1217 		}
1218 	} while (++i < *nr_cluster);
1219 
1220 	memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy);
1221 	offset = copy - sizeof(struct msdos_dir_entry);
1222 	get_bh(bhs[n]);
1223 	*bh = bhs[n];
1224 	*de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
1225 	*i_pos = fat_make_i_pos(sb, *bh, *de);
1226 
1227 	/* Second stage: clear the rest of cluster, and write outs */
1228 	err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE);
1229 	if (err)
1230 		goto error_free;
1231 
1232 	return cluster[0];
1233 
1234 error_free:
1235 	brelse(*bh);
1236 	*bh = NULL;
1237 	n = 0;
1238 error_nomem:
1239 	for (i = 0; i < n; i++)
1240 		bforget(bhs[i]);
1241 	fat_free_clusters(dir, cluster[0]);
1242 error:
1243 	return err;
1244 }
1245 
1246 int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
1247 		    struct fat_slot_info *sinfo)
1248 {
1249 	struct super_block *sb = dir->i_sb;
1250 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
1251 	struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */
1252 	struct msdos_dir_entry *uninitialized_var(de);
1253 	int err, free_slots, i, nr_bhs;
1254 	loff_t pos, i_pos;
1255 
1256 	sinfo->nr_slots = nr_slots;
1257 
1258 	/* First stage: search free direcotry entries */
1259 	free_slots = nr_bhs = 0;
1260 	bh = prev = NULL;
1261 	pos = 0;
1262 	err = -ENOSPC;
1263 	while (fat_get_entry(dir, &pos, &bh, &de) > -1) {
1264 		/* check the maximum size of directory */
1265 		if (pos >= FAT_MAX_DIR_SIZE)
1266 			goto error;
1267 
1268 		if (IS_FREE(de->name)) {
1269 			if (prev != bh) {
1270 				get_bh(bh);
1271 				bhs[nr_bhs] = prev = bh;
1272 				nr_bhs++;
1273 			}
1274 			free_slots++;
1275 			if (free_slots == nr_slots)
1276 				goto found;
1277 		} else {
1278 			for (i = 0; i < nr_bhs; i++)
1279 				brelse(bhs[i]);
1280 			prev = NULL;
1281 			free_slots = nr_bhs = 0;
1282 		}
1283 	}
1284 	if (dir->i_ino == MSDOS_ROOT_INO) {
1285 		if (sbi->fat_bits != 32)
1286 			goto error;
1287 	} else if (MSDOS_I(dir)->i_start == 0) {
1288 		fat_msg(sb, KERN_ERR, "Corrupted directory (i_pos %lld)",
1289 		       MSDOS_I(dir)->i_pos);
1290 		err = -EIO;
1291 		goto error;
1292 	}
1293 
1294 found:
1295 	err = 0;
1296 	pos -= free_slots * sizeof(*de);
1297 	nr_slots -= free_slots;
1298 	if (free_slots) {
1299 		/*
1300 		 * Second stage: filling the free entries with new entries.
1301 		 * NOTE: If this slots has shortname, first, we write
1302 		 * the long name slots, then write the short name.
1303 		 */
1304 		int size = free_slots * sizeof(*de);
1305 		int offset = pos & (sb->s_blocksize - 1);
1306 		int long_bhs = nr_bhs - (nr_slots == 0);
1307 
1308 		/* Fill the long name slots. */
1309 		for (i = 0; i < long_bhs; i++) {
1310 			int copy = min_t(int, sb->s_blocksize - offset, size);
1311 			memcpy(bhs[i]->b_data + offset, slots, copy);
1312 			mark_buffer_dirty_inode(bhs[i], dir);
1313 			offset = 0;
1314 			slots += copy;
1315 			size -= copy;
1316 		}
1317 		if (long_bhs && IS_DIRSYNC(dir))
1318 			err = fat_sync_bhs(bhs, long_bhs);
1319 		if (!err && i < nr_bhs) {
1320 			/* Fill the short name slot. */
1321 			int copy = min_t(int, sb->s_blocksize - offset, size);
1322 			memcpy(bhs[i]->b_data + offset, slots, copy);
1323 			mark_buffer_dirty_inode(bhs[i], dir);
1324 			if (IS_DIRSYNC(dir))
1325 				err = sync_dirty_buffer(bhs[i]);
1326 		}
1327 		for (i = 0; i < nr_bhs; i++)
1328 			brelse(bhs[i]);
1329 		if (err)
1330 			goto error_remove;
1331 	}
1332 
1333 	if (nr_slots) {
1334 		int cluster, nr_cluster;
1335 
1336 		/*
1337 		 * Third stage: allocate the cluster for new entries.
1338 		 * And initialize the cluster with new entries, then
1339 		 * add the cluster to dir.
1340 		 */
1341 		cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster,
1342 					      &de, &bh, &i_pos);
1343 		if (cluster < 0) {
1344 			err = cluster;
1345 			goto error_remove;
1346 		}
1347 		err = fat_chain_add(dir, cluster, nr_cluster);
1348 		if (err) {
1349 			fat_free_clusters(dir, cluster);
1350 			goto error_remove;
1351 		}
1352 		if (dir->i_size & (sbi->cluster_size - 1)) {
1353 			fat_fs_error(sb, "Odd directory size");
1354 			dir->i_size = (dir->i_size + sbi->cluster_size - 1)
1355 				& ~((loff_t)sbi->cluster_size - 1);
1356 		}
1357 		dir->i_size += nr_cluster << sbi->cluster_bits;
1358 		MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits;
1359 	}
1360 	sinfo->slot_off = pos;
1361 	sinfo->de = de;
1362 	sinfo->bh = bh;
1363 	sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
1364 
1365 	return 0;
1366 
1367 error:
1368 	brelse(bh);
1369 	for (i = 0; i < nr_bhs; i++)
1370 		brelse(bhs[i]);
1371 	return err;
1372 
1373 error_remove:
1374 	brelse(bh);
1375 	if (free_slots)
1376 		__fat_remove_entries(dir, pos, free_slots);
1377 	return err;
1378 }
1379 EXPORT_SYMBOL_GPL(fat_add_entries);
1380