xref: /openbmc/linux/fs/fat/dir.c (revision e4c0d0e2)
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 <asm/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 loff_t fat_make_i_pos(struct super_block *sb,
39 				    struct buffer_head *bh,
40 				    struct msdos_dir_entry *de)
41 {
42 	return ((loff_t)bh->b_blocknr << MSDOS_SB(sb)->dir_per_block_bits)
43 		| (de - (struct msdos_dir_entry *)bh->b_data);
44 }
45 
46 static inline void fat_dir_readahead(struct inode *dir, sector_t iblock,
47 				     sector_t phys)
48 {
49 	struct super_block *sb = dir->i_sb;
50 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
51 	struct buffer_head *bh;
52 	int sec;
53 
54 	/* This is not a first sector of cluster, or sec_per_clus == 1 */
55 	if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1)
56 		return;
57 	/* root dir of FAT12/FAT16 */
58 	if ((sbi->fat_bits != 32) && (dir->i_ino == MSDOS_ROOT_INO))
59 		return;
60 
61 	bh = sb_find_get_block(sb, phys);
62 	if (bh == NULL || !buffer_uptodate(bh)) {
63 		for (sec = 0; sec < sbi->sec_per_clus; sec++)
64 			sb_breadahead(sb, phys + sec);
65 	}
66 	brelse(bh);
67 }
68 
69 /* Returns the inode number of the directory entry at offset pos. If bh is
70    non-NULL, it is brelse'd before. Pos is incremented. The buffer header is
71    returned in bh.
72    AV. Most often we do it item-by-item. Makes sense to optimize.
73    AV. OK, there we go: if both bh and de are non-NULL we assume that we just
74    AV. want the next entry (took one explicit de=NULL in vfat/namei.c).
75    AV. It's done in fat_get_entry() (inlined), here the slow case lives.
76    AV. Additionally, when we return -1 (i.e. reached the end of directory)
77    AV. we make bh NULL.
78  */
79 static int fat__get_entry(struct inode *dir, loff_t *pos,
80 			  struct buffer_head **bh, struct msdos_dir_entry **de)
81 {
82 	struct super_block *sb = dir->i_sb;
83 	sector_t phys, iblock;
84 	unsigned long mapped_blocks;
85 	int err, offset;
86 
87 next:
88 	if (*bh)
89 		brelse(*bh);
90 
91 	*bh = NULL;
92 	iblock = *pos >> sb->s_blocksize_bits;
93 	err = fat_bmap(dir, iblock, &phys, &mapped_blocks, 0);
94 	if (err || !phys)
95 		return -1;	/* beyond EOF or error */
96 
97 	fat_dir_readahead(dir, iblock, phys);
98 
99 	*bh = sb_bread(sb, phys);
100 	if (*bh == NULL) {
101 		fat_msg(sb, KERN_ERR, "Directory bread(block %llu) failed",
102 		       (llu)phys);
103 		/* skip this block */
104 		*pos = (iblock + 1) << sb->s_blocksize_bits;
105 		goto next;
106 	}
107 
108 	offset = *pos & (sb->s_blocksize - 1);
109 	*pos += sizeof(struct msdos_dir_entry);
110 	*de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
111 
112 	return 0;
113 }
114 
115 static inline int fat_get_entry(struct inode *dir, loff_t *pos,
116 				struct buffer_head **bh,
117 				struct msdos_dir_entry **de)
118 {
119 	/* Fast stuff first */
120 	if (*bh && *de &&
121 	    (*de - (struct msdos_dir_entry *)(*bh)->b_data) < MSDOS_SB(dir->i_sb)->dir_per_block - 1) {
122 		*pos += sizeof(struct msdos_dir_entry);
123 		(*de)++;
124 		return 0;
125 	}
126 	return fat__get_entry(dir, pos, bh, de);
127 }
128 
129 /*
130  * Convert Unicode 16 to UTF-8, translated Unicode, or ASCII.
131  * If uni_xlate is enabled and we can't get a 1:1 conversion, use a
132  * colon as an escape character since it is normally invalid on the vfat
133  * filesystem. The following four characters are the hexadecimal digits
134  * of Unicode value. This lets us do a full dump and restore of Unicode
135  * filenames. We could get into some trouble with long Unicode names,
136  * but ignore that right now.
137  * Ahem... Stack smashing in ring 0 isn't fun. Fixed.
138  */
139 static int uni16_to_x8(struct super_block *sb, unsigned char *ascii,
140 		       const wchar_t *uni, int len, struct nls_table *nls)
141 {
142 	int uni_xlate = MSDOS_SB(sb)->options.unicode_xlate;
143 	const wchar_t *ip;
144 	wchar_t ec;
145 	unsigned char *op;
146 	int charlen;
147 
148 	ip = uni;
149 	op = ascii;
150 
151 	while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {
152 		ec = *ip++;
153 		if ((charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE)) > 0) {
154 			op += charlen;
155 			len -= charlen;
156 		} else {
157 			if (uni_xlate == 1) {
158 				*op++ = ':';
159 				op = pack_hex_byte(op, ec >> 8);
160 				op = pack_hex_byte(op, ec);
161 				len -= 5;
162 			} else {
163 				*op++ = '?';
164 				len--;
165 			}
166 		}
167 	}
168 
169 	if (unlikely(*ip)) {
170 		fat_msg(sb, KERN_WARNING, "filename was truncated while "
171 			"converting.");
172 	}
173 
174 	*op = 0;
175 	return (op - ascii);
176 }
177 
178 static inline int fat_uni_to_x8(struct super_block *sb, const wchar_t *uni,
179 				unsigned char *buf, int size)
180 {
181 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
182 	if (sbi->options.utf8)
183 		return utf16s_to_utf8s(uni, FAT_MAX_UNI_CHARS,
184 				UTF16_HOST_ENDIAN, buf, size);
185 	else
186 		return uni16_to_x8(sb, buf, uni, size, sbi->nls_io);
187 }
188 
189 static inline int
190 fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
191 {
192 	int charlen;
193 
194 	charlen = t->char2uni(c, clen, uni);
195 	if (charlen < 0) {
196 		*uni = 0x003f;	/* a question mark */
197 		charlen = 1;
198 	}
199 	return charlen;
200 }
201 
202 static inline int
203 fat_short2lower_uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
204 {
205 	int charlen;
206 	wchar_t wc;
207 
208 	charlen = t->char2uni(c, clen, &wc);
209 	if (charlen < 0) {
210 		*uni = 0x003f;	/* a question mark */
211 		charlen = 1;
212 	} else if (charlen <= 1) {
213 		unsigned char nc = t->charset2lower[*c];
214 
215 		if (!nc)
216 			nc = *c;
217 
218 		if ( (charlen = t->char2uni(&nc, 1, uni)) < 0) {
219 			*uni = 0x003f;	/* a question mark */
220 			charlen = 1;
221 		}
222 	} else
223 		*uni = wc;
224 
225 	return charlen;
226 }
227 
228 static inline int
229 fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size,
230 		  wchar_t *uni_buf, unsigned short opt, int lower)
231 {
232 	int len = 0;
233 
234 	if (opt & VFAT_SFN_DISPLAY_LOWER)
235 		len =  fat_short2lower_uni(nls, buf, buf_size, uni_buf);
236 	else if (opt & VFAT_SFN_DISPLAY_WIN95)
237 		len = fat_short2uni(nls, buf, buf_size, uni_buf);
238 	else if (opt & VFAT_SFN_DISPLAY_WINNT) {
239 		if (lower)
240 			len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
241 		else
242 			len = fat_short2uni(nls, buf, buf_size, uni_buf);
243 	} else
244 		len = fat_short2uni(nls, buf, buf_size, uni_buf);
245 
246 	return len;
247 }
248 
249 static inline int fat_name_match(struct msdos_sb_info *sbi,
250 				 const unsigned char *a, int a_len,
251 				 const unsigned char *b, int b_len)
252 {
253 	if (a_len != b_len)
254 		return 0;
255 
256 	if (sbi->options.name_check != 's')
257 		return !nls_strnicmp(sbi->nls_io, a, b, a_len);
258 	else
259 		return !memcmp(a, b, a_len);
260 }
261 
262 enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, };
263 
264 /**
265  * fat_parse_long - Parse extended directory entry.
266  *
267  * This function returns zero on success, negative value on error, or one of
268  * the following:
269  *
270  * %PARSE_INVALID - Directory entry is invalid.
271  * %PARSE_NOT_LONGNAME - Directory entry does not contain longname.
272  * %PARSE_EOF - Directory has no more entries.
273  */
274 static int fat_parse_long(struct inode *dir, loff_t *pos,
275 			  struct buffer_head **bh, struct msdos_dir_entry **de,
276 			  wchar_t **unicode, unsigned char *nr_slots)
277 {
278 	struct msdos_dir_slot *ds;
279 	unsigned char id, slot, slots, alias_checksum;
280 
281 	if (!*unicode) {
282 		*unicode = __getname();
283 		if (!*unicode) {
284 			brelse(*bh);
285 			return -ENOMEM;
286 		}
287 	}
288 parse_long:
289 	slots = 0;
290 	ds = (struct msdos_dir_slot *)*de;
291 	id = ds->id;
292 	if (!(id & 0x40))
293 		return PARSE_INVALID;
294 	slots = id & ~0x40;
295 	if (slots > 20 || !slots)	/* ceil(256 * 2 / 26) */
296 		return PARSE_INVALID;
297 	*nr_slots = slots;
298 	alias_checksum = ds->alias_checksum;
299 
300 	slot = slots;
301 	while (1) {
302 		int offset;
303 
304 		slot--;
305 		offset = slot * 13;
306 		fat16_towchar(*unicode + offset, ds->name0_4, 5);
307 		fat16_towchar(*unicode + offset + 5, ds->name5_10, 6);
308 		fat16_towchar(*unicode + offset + 11, ds->name11_12, 2);
309 
310 		if (ds->id & 0x40)
311 			(*unicode)[offset + 13] = 0;
312 		if (fat_get_entry(dir, pos, bh, de) < 0)
313 			return PARSE_EOF;
314 		if (slot == 0)
315 			break;
316 		ds = (struct msdos_dir_slot *)*de;
317 		if (ds->attr != ATTR_EXT)
318 			return PARSE_NOT_LONGNAME;
319 		if ((ds->id & ~0x40) != slot)
320 			goto parse_long;
321 		if (ds->alias_checksum != alias_checksum)
322 			goto parse_long;
323 	}
324 	if ((*de)->name[0] == DELETED_FLAG)
325 		return PARSE_INVALID;
326 	if ((*de)->attr == ATTR_EXT)
327 		goto parse_long;
328 	if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME))
329 		return PARSE_INVALID;
330 	if (fat_checksum((*de)->name) != alias_checksum)
331 		*nr_slots = 0;
332 
333 	return 0;
334 }
335 
336 /*
337  * Return values: negative -> error, 0 -> not found, positive -> found,
338  * value is the total amount of slots, including the shortname entry.
339  */
340 int fat_search_long(struct inode *inode, const unsigned char *name,
341 		    int name_len, struct fat_slot_info *sinfo)
342 {
343 	struct super_block *sb = inode->i_sb;
344 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
345 	struct buffer_head *bh = NULL;
346 	struct msdos_dir_entry *de;
347 	struct nls_table *nls_disk = sbi->nls_disk;
348 	unsigned char nr_slots;
349 	wchar_t bufuname[14];
350 	wchar_t *unicode = NULL;
351 	unsigned char work[MSDOS_NAME];
352 	unsigned char bufname[FAT_MAX_SHORT_SIZE];
353 	unsigned short opt_shortname = sbi->options.shortname;
354 	loff_t cpos = 0;
355 	int chl, i, j, last_u, err, len;
356 
357 	err = -ENOENT;
358 	while (1) {
359 		if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
360 			goto end_of_dir;
361 parse_record:
362 		nr_slots = 0;
363 		if (de->name[0] == DELETED_FLAG)
364 			continue;
365 		if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
366 			continue;
367 		if (de->attr != ATTR_EXT && IS_FREE(de->name))
368 			continue;
369 		if (de->attr == ATTR_EXT) {
370 			int status = fat_parse_long(inode, &cpos, &bh, &de,
371 						    &unicode, &nr_slots);
372 			if (status < 0) {
373 				err = status;
374 				goto end_of_dir;
375 			} else if (status == PARSE_INVALID)
376 				continue;
377 			else if (status == PARSE_NOT_LONGNAME)
378 				goto parse_record;
379 			else if (status == PARSE_EOF)
380 				goto end_of_dir;
381 		}
382 
383 		memcpy(work, de->name, sizeof(de->name));
384 		/* see namei.c, msdos_format_name */
385 		if (work[0] == 0x05)
386 			work[0] = 0xE5;
387 		for (i = 0, j = 0, last_u = 0; i < 8;) {
388 			if (!work[i])
389 				break;
390 			chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
391 						&bufuname[j++], opt_shortname,
392 						de->lcase & CASE_LOWER_BASE);
393 			if (chl <= 1) {
394 				if (work[i] != ' ')
395 					last_u = j;
396 			} else {
397 				last_u = j;
398 			}
399 			i += chl;
400 		}
401 		j = last_u;
402 		fat_short2uni(nls_disk, ".", 1, &bufuname[j++]);
403 		for (i = 8; i < MSDOS_NAME;) {
404 			if (!work[i])
405 				break;
406 			chl = fat_shortname2uni(nls_disk, &work[i],
407 						MSDOS_NAME - i,
408 						&bufuname[j++], opt_shortname,
409 						de->lcase & CASE_LOWER_EXT);
410 			if (chl <= 1) {
411 				if (work[i] != ' ')
412 					last_u = j;
413 			} else {
414 				last_u = j;
415 			}
416 			i += chl;
417 		}
418 		if (!last_u)
419 			continue;
420 
421 		/* Compare shortname */
422 		bufuname[last_u] = 0x0000;
423 		len = fat_uni_to_x8(sb, bufuname, bufname, sizeof(bufname));
424 		if (fat_name_match(sbi, name, name_len, bufname, len))
425 			goto found;
426 
427 		if (nr_slots) {
428 			void *longname = unicode + FAT_MAX_UNI_CHARS;
429 			int size = PATH_MAX - FAT_MAX_UNI_SIZE;
430 
431 			/* Compare longname */
432 			len = fat_uni_to_x8(sb, unicode, longname, size);
433 			if (fat_name_match(sbi, name, name_len, longname, len))
434 				goto found;
435 		}
436 	}
437 
438 found:
439 	nr_slots++;	/* include the de */
440 	sinfo->slot_off = cpos - nr_slots * sizeof(*de);
441 	sinfo->nr_slots = nr_slots;
442 	sinfo->de = de;
443 	sinfo->bh = bh;
444 	sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
445 	err = 0;
446 end_of_dir:
447 	if (unicode)
448 		__putname(unicode);
449 
450 	return err;
451 }
452 
453 EXPORT_SYMBOL_GPL(fat_search_long);
454 
455 struct fat_ioctl_filldir_callback {
456 	void __user *dirent;
457 	int result;
458 	/* for dir ioctl */
459 	const char *longname;
460 	int long_len;
461 	const char *shortname;
462 	int short_len;
463 };
464 
465 static int __fat_readdir(struct inode *inode, struct file *filp, void *dirent,
466 			 filldir_t filldir, int short_only, int both)
467 {
468 	struct super_block *sb = inode->i_sb;
469 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
470 	struct buffer_head *bh;
471 	struct msdos_dir_entry *de;
472 	struct nls_table *nls_disk = sbi->nls_disk;
473 	unsigned char nr_slots;
474 	wchar_t bufuname[14];
475 	wchar_t *unicode = NULL;
476 	unsigned char c, work[MSDOS_NAME];
477 	unsigned char bufname[FAT_MAX_SHORT_SIZE], *ptname = bufname;
478 	unsigned short opt_shortname = sbi->options.shortname;
479 	int isvfat = sbi->options.isvfat;
480 	int nocase = sbi->options.nocase;
481 	const char *fill_name = NULL;
482 	unsigned long inum;
483 	unsigned long lpos, dummy, *furrfu = &lpos;
484 	loff_t cpos;
485 	int chi, chl, i, i2, j, last, last_u, dotoffset = 0, fill_len = 0;
486 	int ret = 0;
487 
488 	lock_super(sb);
489 
490 	cpos = filp->f_pos;
491 	/* Fake . and .. for the root directory. */
492 	if (inode->i_ino == MSDOS_ROOT_INO) {
493 		while (cpos < 2) {
494 			if (filldir(dirent, "..", cpos+1, cpos, MSDOS_ROOT_INO, DT_DIR) < 0)
495 				goto out;
496 			cpos++;
497 			filp->f_pos++;
498 		}
499 		if (cpos == 2) {
500 			dummy = 2;
501 			furrfu = &dummy;
502 			cpos = 0;
503 		}
504 	}
505 	if (cpos & (sizeof(struct msdos_dir_entry) - 1)) {
506 		ret = -ENOENT;
507 		goto out;
508 	}
509 
510 	bh = NULL;
511 get_new:
512 	if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
513 		goto end_of_dir;
514 parse_record:
515 	nr_slots = 0;
516 	/*
517 	 * Check for long filename entry, but if short_only, we don't
518 	 * need to parse long filename.
519 	 */
520 	if (isvfat && !short_only) {
521 		if (de->name[0] == DELETED_FLAG)
522 			goto record_end;
523 		if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
524 			goto record_end;
525 		if (de->attr != ATTR_EXT && IS_FREE(de->name))
526 			goto record_end;
527 	} else {
528 		if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))
529 			goto record_end;
530 	}
531 
532 	if (isvfat && de->attr == ATTR_EXT) {
533 		int status = fat_parse_long(inode, &cpos, &bh, &de,
534 					    &unicode, &nr_slots);
535 		if (status < 0) {
536 			filp->f_pos = cpos;
537 			ret = status;
538 			goto out;
539 		} else if (status == PARSE_INVALID)
540 			goto record_end;
541 		else if (status == PARSE_NOT_LONGNAME)
542 			goto parse_record;
543 		else if (status == PARSE_EOF)
544 			goto end_of_dir;
545 
546 		if (nr_slots) {
547 			void *longname = unicode + FAT_MAX_UNI_CHARS;
548 			int size = PATH_MAX - FAT_MAX_UNI_SIZE;
549 			int len = fat_uni_to_x8(sb, unicode, longname, size);
550 
551 			fill_name = longname;
552 			fill_len = len;
553 			/* !both && !short_only, so we don't need shortname. */
554 			if (!both)
555 				goto start_filldir;
556 		}
557 	}
558 
559 	if (sbi->options.dotsOK) {
560 		ptname = bufname;
561 		dotoffset = 0;
562 		if (de->attr & ATTR_HIDDEN) {
563 			*ptname++ = '.';
564 			dotoffset = 1;
565 		}
566 	}
567 
568 	memcpy(work, de->name, sizeof(de->name));
569 	/* see namei.c, msdos_format_name */
570 	if (work[0] == 0x05)
571 		work[0] = 0xE5;
572 	for (i = 0, j = 0, last = 0, last_u = 0; i < 8;) {
573 		if (!(c = work[i]))
574 			break;
575 		chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
576 					&bufuname[j++], opt_shortname,
577 					de->lcase & CASE_LOWER_BASE);
578 		if (chl <= 1) {
579 			ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c;
580 			if (c != ' ') {
581 				last = i;
582 				last_u = j;
583 			}
584 		} else {
585 			last_u = j;
586 			for (chi = 0; chi < chl && i < 8; chi++) {
587 				ptname[i] = work[i];
588 				i++; last = i;
589 			}
590 		}
591 	}
592 	i = last;
593 	j = last_u;
594 	fat_short2uni(nls_disk, ".", 1, &bufuname[j++]);
595 	ptname[i++] = '.';
596 	for (i2 = 8; i2 < MSDOS_NAME;) {
597 		if (!(c = work[i2]))
598 			break;
599 		chl = fat_shortname2uni(nls_disk, &work[i2], MSDOS_NAME - i2,
600 					&bufuname[j++], opt_shortname,
601 					de->lcase & CASE_LOWER_EXT);
602 		if (chl <= 1) {
603 			i2++;
604 			ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c;
605 			if (c != ' ') {
606 				last = i;
607 				last_u = j;
608 			}
609 		} else {
610 			last_u = j;
611 			for (chi = 0; chi < chl && i2 < MSDOS_NAME; chi++) {
612 				ptname[i++] = work[i2++];
613 				last = i;
614 			}
615 		}
616 	}
617 	if (!last)
618 		goto record_end;
619 
620 	i = last + dotoffset;
621 	j = last_u;
622 
623 	if (isvfat) {
624 		bufuname[j] = 0x0000;
625 		i = fat_uni_to_x8(sb, bufuname, bufname, sizeof(bufname));
626 	}
627 	if (nr_slots) {
628 		/* hack for fat_ioctl_filldir() */
629 		struct fat_ioctl_filldir_callback *p = dirent;
630 
631 		p->longname = fill_name;
632 		p->long_len = fill_len;
633 		p->shortname = bufname;
634 		p->short_len = i;
635 		fill_name = NULL;
636 		fill_len = 0;
637 	} else {
638 		fill_name = bufname;
639 		fill_len = i;
640 	}
641 
642 start_filldir:
643 	lpos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
644 	if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME))
645 		inum = inode->i_ino;
646 	else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
647 		inum = parent_ino(filp->f_path.dentry);
648 	} else {
649 		loff_t i_pos = fat_make_i_pos(sb, bh, de);
650 		struct inode *tmp = fat_iget(sb, i_pos);
651 		if (tmp) {
652 			inum = tmp->i_ino;
653 			iput(tmp);
654 		} else
655 			inum = iunique(sb, MSDOS_ROOT_INO);
656 	}
657 
658 	if (filldir(dirent, fill_name, fill_len, *furrfu, inum,
659 		    (de->attr & ATTR_DIR) ? DT_DIR : DT_REG) < 0)
660 		goto fill_failed;
661 
662 record_end:
663 	furrfu = &lpos;
664 	filp->f_pos = cpos;
665 	goto get_new;
666 end_of_dir:
667 	filp->f_pos = cpos;
668 fill_failed:
669 	brelse(bh);
670 	if (unicode)
671 		__putname(unicode);
672 out:
673 	unlock_super(sb);
674 	return ret;
675 }
676 
677 static int fat_readdir(struct file *filp, void *dirent, filldir_t filldir)
678 {
679 	struct inode *inode = filp->f_path.dentry->d_inode;
680 	return __fat_readdir(inode, filp, dirent, filldir, 0, 0);
681 }
682 
683 #define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type)			   \
684 static int func(void *__buf, const char *name, int name_len,		   \
685 			     loff_t offset, u64 ino, unsigned int d_type)  \
686 {									   \
687 	struct fat_ioctl_filldir_callback *buf = __buf;			   \
688 	struct dirent_type __user *d1 = buf->dirent;			   \
689 	struct dirent_type __user *d2 = d1 + 1;				   \
690 									   \
691 	if (buf->result)						   \
692 		return -EINVAL;						   \
693 	buf->result++;							   \
694 									   \
695 	if (name != NULL) {						   \
696 		/* dirent has only short name */			   \
697 		if (name_len >= sizeof(d1->d_name))			   \
698 			name_len = sizeof(d1->d_name) - 1;		   \
699 									   \
700 		if (put_user(0, d2->d_name)			||	   \
701 		    put_user(0, &d2->d_reclen)			||	   \
702 		    copy_to_user(d1->d_name, name, name_len)	||	   \
703 		    put_user(0, d1->d_name + name_len)		||	   \
704 		    put_user(name_len, &d1->d_reclen))			   \
705 			goto efault;					   \
706 	} else {							   \
707 		/* dirent has short and long name */			   \
708 		const char *longname = buf->longname;			   \
709 		int long_len = buf->long_len;				   \
710 		const char *shortname = buf->shortname;			   \
711 		int short_len = buf->short_len;				   \
712 									   \
713 		if (long_len >= sizeof(d1->d_name))			   \
714 			long_len = sizeof(d1->d_name) - 1;		   \
715 		if (short_len >= sizeof(d1->d_name))			   \
716 			short_len = sizeof(d1->d_name) - 1;		   \
717 									   \
718 		if (copy_to_user(d2->d_name, longname, long_len)	|| \
719 		    put_user(0, d2->d_name + long_len)			|| \
720 		    put_user(long_len, &d2->d_reclen)			|| \
721 		    put_user(ino, &d2->d_ino)				|| \
722 		    put_user(offset, &d2->d_off)			|| \
723 		    copy_to_user(d1->d_name, shortname, short_len)	|| \
724 		    put_user(0, d1->d_name + short_len)			|| \
725 		    put_user(short_len, &d1->d_reclen))			   \
726 			goto efault;					   \
727 	}								   \
728 	return 0;							   \
729 efault:									   \
730 	buf->result = -EFAULT;						   \
731 	return -EFAULT;							   \
732 }
733 
734 FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)
735 
736 static int fat_ioctl_readdir(struct inode *inode, struct file *filp,
737 			     void __user *dirent, filldir_t filldir,
738 			     int short_only, int both)
739 {
740 	struct fat_ioctl_filldir_callback buf;
741 	int ret;
742 
743 	buf.dirent = dirent;
744 	buf.result = 0;
745 	mutex_lock(&inode->i_mutex);
746 	ret = -ENOENT;
747 	if (!IS_DEADDIR(inode)) {
748 		ret = __fat_readdir(inode, filp, &buf, filldir,
749 				    short_only, both);
750 	}
751 	mutex_unlock(&inode->i_mutex);
752 	if (ret >= 0)
753 		ret = buf.result;
754 	return ret;
755 }
756 
757 static long fat_dir_ioctl(struct file *filp, unsigned int cmd,
758 			  unsigned long arg)
759 {
760 	struct inode *inode = filp->f_path.dentry->d_inode;
761 	struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg;
762 	int short_only, both;
763 
764 	switch (cmd) {
765 	case VFAT_IOCTL_READDIR_SHORT:
766 		short_only = 1;
767 		both = 0;
768 		break;
769 	case VFAT_IOCTL_READDIR_BOTH:
770 		short_only = 0;
771 		both = 1;
772 		break;
773 	default:
774 		return fat_generic_ioctl(filp, cmd, arg);
775 	}
776 
777 	if (!access_ok(VERIFY_WRITE, d1, sizeof(struct __fat_dirent[2])))
778 		return -EFAULT;
779 	/*
780 	 * Yes, we don't need this put_user() absolutely. However old
781 	 * code didn't return the right value. So, app use this value,
782 	 * in order to check whether it is EOF.
783 	 */
784 	if (put_user(0, &d1->d_reclen))
785 		return -EFAULT;
786 
787 	return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir,
788 				 short_only, both);
789 }
790 
791 #ifdef CONFIG_COMPAT
792 #define	VFAT_IOCTL_READDIR_BOTH32	_IOR('r', 1, struct compat_dirent[2])
793 #define	VFAT_IOCTL_READDIR_SHORT32	_IOR('r', 2, struct compat_dirent[2])
794 
795 FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent)
796 
797 static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd,
798 				 unsigned long arg)
799 {
800 	struct inode *inode = filp->f_path.dentry->d_inode;
801 	struct compat_dirent __user *d1 = compat_ptr(arg);
802 	int short_only, both;
803 
804 	switch (cmd) {
805 	case VFAT_IOCTL_READDIR_SHORT32:
806 		short_only = 1;
807 		both = 0;
808 		break;
809 	case VFAT_IOCTL_READDIR_BOTH32:
810 		short_only = 0;
811 		both = 1;
812 		break;
813 	default:
814 		return fat_generic_ioctl(filp, cmd, (unsigned long)arg);
815 	}
816 
817 	if (!access_ok(VERIFY_WRITE, d1, sizeof(struct compat_dirent[2])))
818 		return -EFAULT;
819 	/*
820 	 * Yes, we don't need this put_user() absolutely. However old
821 	 * code didn't return the right value. So, app use this value,
822 	 * in order to check whether it is EOF.
823 	 */
824 	if (put_user(0, &d1->d_reclen))
825 		return -EFAULT;
826 
827 	return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir,
828 				 short_only, both);
829 }
830 #endif /* CONFIG_COMPAT */
831 
832 const struct file_operations fat_dir_operations = {
833 	.llseek		= generic_file_llseek,
834 	.read		= generic_read_dir,
835 	.readdir	= fat_readdir,
836 	.unlocked_ioctl	= fat_dir_ioctl,
837 #ifdef CONFIG_COMPAT
838 	.compat_ioctl	= fat_compat_dir_ioctl,
839 #endif
840 	.fsync		= fat_file_fsync,
841 };
842 
843 static int fat_get_short_entry(struct inode *dir, loff_t *pos,
844 			       struct buffer_head **bh,
845 			       struct msdos_dir_entry **de)
846 {
847 	while (fat_get_entry(dir, pos, bh, de) >= 0) {
848 		/* free entry or long name entry or volume label */
849 		if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))
850 			return 0;
851 	}
852 	return -ENOENT;
853 }
854 
855 /*
856  * The ".." entry can not provide the "struct fat_slot_info" informations
857  * for inode. So, this function provide the some informations only.
858  */
859 int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
860 			 struct msdos_dir_entry **de, loff_t *i_pos)
861 {
862 	loff_t offset;
863 
864 	offset = 0;
865 	*bh = NULL;
866 	while (fat_get_short_entry(dir, &offset, bh, de) >= 0) {
867 		if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME)) {
868 			*i_pos = fat_make_i_pos(dir->i_sb, *bh, *de);
869 			return 0;
870 		}
871 	}
872 	return -ENOENT;
873 }
874 
875 EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);
876 
877 /* See if directory is empty */
878 int fat_dir_empty(struct inode *dir)
879 {
880 	struct buffer_head *bh;
881 	struct msdos_dir_entry *de;
882 	loff_t cpos;
883 	int result = 0;
884 
885 	bh = NULL;
886 	cpos = 0;
887 	while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
888 		if (strncmp(de->name, MSDOS_DOT   , MSDOS_NAME) &&
889 		    strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
890 			result = -ENOTEMPTY;
891 			break;
892 		}
893 	}
894 	brelse(bh);
895 	return result;
896 }
897 
898 EXPORT_SYMBOL_GPL(fat_dir_empty);
899 
900 /*
901  * fat_subdirs counts the number of sub-directories of dir. It can be run
902  * on directories being created.
903  */
904 int fat_subdirs(struct inode *dir)
905 {
906 	struct buffer_head *bh;
907 	struct msdos_dir_entry *de;
908 	loff_t cpos;
909 	int count = 0;
910 
911 	bh = NULL;
912 	cpos = 0;
913 	while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
914 		if (de->attr & ATTR_DIR)
915 			count++;
916 	}
917 	brelse(bh);
918 	return count;
919 }
920 
921 /*
922  * Scans a directory for a given file (name points to its formatted name).
923  * Returns an error code or zero.
924  */
925 int fat_scan(struct inode *dir, const unsigned char *name,
926 	     struct fat_slot_info *sinfo)
927 {
928 	struct super_block *sb = dir->i_sb;
929 
930 	sinfo->slot_off = 0;
931 	sinfo->bh = NULL;
932 	while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
933 				   &sinfo->de) >= 0) {
934 		if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) {
935 			sinfo->slot_off -= sizeof(*sinfo->de);
936 			sinfo->nr_slots = 1;
937 			sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
938 			return 0;
939 		}
940 	}
941 	return -ENOENT;
942 }
943 
944 EXPORT_SYMBOL_GPL(fat_scan);
945 
946 static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)
947 {
948 	struct super_block *sb = dir->i_sb;
949 	struct buffer_head *bh;
950 	struct msdos_dir_entry *de, *endp;
951 	int err = 0, orig_slots;
952 
953 	while (nr_slots) {
954 		bh = NULL;
955 		if (fat_get_entry(dir, &pos, &bh, &de) < 0) {
956 			err = -EIO;
957 			break;
958 		}
959 
960 		orig_slots = nr_slots;
961 		endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize);
962 		while (nr_slots && de < endp) {
963 			de->name[0] = DELETED_FLAG;
964 			de++;
965 			nr_slots--;
966 		}
967 		mark_buffer_dirty_inode(bh, dir);
968 		if (IS_DIRSYNC(dir))
969 			err = sync_dirty_buffer(bh);
970 		brelse(bh);
971 		if (err)
972 			break;
973 
974 		/* pos is *next* de's position, so this does `- sizeof(de)' */
975 		pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de);
976 	}
977 
978 	return err;
979 }
980 
981 int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)
982 {
983 	struct super_block *sb = dir->i_sb;
984 	struct msdos_dir_entry *de;
985 	struct buffer_head *bh;
986 	int err = 0, nr_slots;
987 
988 	/*
989 	 * First stage: Remove the shortname. By this, the directory
990 	 * entry is removed.
991 	 */
992 	nr_slots = sinfo->nr_slots;
993 	de = sinfo->de;
994 	sinfo->de = NULL;
995 	bh = sinfo->bh;
996 	sinfo->bh = NULL;
997 	while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) {
998 		de->name[0] = DELETED_FLAG;
999 		de--;
1000 		nr_slots--;
1001 	}
1002 	mark_buffer_dirty_inode(bh, dir);
1003 	if (IS_DIRSYNC(dir))
1004 		err = sync_dirty_buffer(bh);
1005 	brelse(bh);
1006 	if (err)
1007 		return err;
1008 	dir->i_version++;
1009 
1010 	if (nr_slots) {
1011 		/*
1012 		 * Second stage: remove the remaining longname slots.
1013 		 * (This directory entry is already removed, and so return
1014 		 * the success)
1015 		 */
1016 		err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots);
1017 		if (err) {
1018 			fat_msg(sb, KERN_WARNING,
1019 			       "Couldn't remove the long name slots");
1020 		}
1021 	}
1022 
1023 	dir->i_mtime = dir->i_atime = CURRENT_TIME_SEC;
1024 	if (IS_DIRSYNC(dir))
1025 		(void)fat_sync_inode(dir);
1026 	else
1027 		mark_inode_dirty(dir);
1028 
1029 	return 0;
1030 }
1031 
1032 EXPORT_SYMBOL_GPL(fat_remove_entries);
1033 
1034 static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,
1035 			      struct buffer_head **bhs, int nr_bhs)
1036 {
1037 	struct super_block *sb = dir->i_sb;
1038 	sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus;
1039 	int err, i, n;
1040 
1041 	/* Zeroing the unused blocks on this cluster */
1042 	blknr += nr_used;
1043 	n = nr_used;
1044 	while (blknr < last_blknr) {
1045 		bhs[n] = sb_getblk(sb, blknr);
1046 		if (!bhs[n]) {
1047 			err = -ENOMEM;
1048 			goto error;
1049 		}
1050 		memset(bhs[n]->b_data, 0, sb->s_blocksize);
1051 		set_buffer_uptodate(bhs[n]);
1052 		mark_buffer_dirty_inode(bhs[n], dir);
1053 
1054 		n++;
1055 		blknr++;
1056 		if (n == nr_bhs) {
1057 			if (IS_DIRSYNC(dir)) {
1058 				err = fat_sync_bhs(bhs, n);
1059 				if (err)
1060 					goto error;
1061 			}
1062 			for (i = 0; i < n; i++)
1063 				brelse(bhs[i]);
1064 			n = 0;
1065 		}
1066 	}
1067 	if (IS_DIRSYNC(dir)) {
1068 		err = fat_sync_bhs(bhs, n);
1069 		if (err)
1070 			goto error;
1071 	}
1072 	for (i = 0; i < n; i++)
1073 		brelse(bhs[i]);
1074 
1075 	return 0;
1076 
1077 error:
1078 	for (i = 0; i < n; i++)
1079 		bforget(bhs[i]);
1080 	return err;
1081 }
1082 
1083 int fat_alloc_new_dir(struct inode *dir, struct timespec *ts)
1084 {
1085 	struct super_block *sb = dir->i_sb;
1086 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
1087 	struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1088 	struct msdos_dir_entry *de;
1089 	sector_t blknr;
1090 	__le16 date, time;
1091 	u8 time_cs;
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_time_unix2fat(sbi, ts, &time, &date, &time_cs);
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 	if (sbi->options.isvfat) {
1116 		/* extra timestamps */
1117 		de[0].ctime = de[1].ctime = time;
1118 		de[0].ctime_cs = de[1].ctime_cs = time_cs;
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].ctime_cs = de[1].ctime_cs = 0;
1123 		de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0;
1124 	}
1125 	de[0].start = cpu_to_le16(cluster);
1126 	de[0].starthi = cpu_to_le16(cluster >> 16);
1127 	de[1].start = cpu_to_le16(MSDOS_I(dir)->i_logstart);
1128 	de[1].starthi = cpu_to_le16(MSDOS_I(dir)->i_logstart >> 16);
1129 	de[0].size = de[1].size = 0;
1130 	memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));
1131 	set_buffer_uptodate(bhs[0]);
1132 	mark_buffer_dirty_inode(bhs[0], dir);
1133 
1134 	err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE);
1135 	if (err)
1136 		goto error_free;
1137 
1138 	return cluster;
1139 
1140 error_free:
1141 	fat_free_clusters(dir, cluster);
1142 error:
1143 	return err;
1144 }
1145 
1146 EXPORT_SYMBOL_GPL(fat_alloc_new_dir);
1147 
1148 static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,
1149 			       int *nr_cluster, struct msdos_dir_entry **de,
1150 			       struct buffer_head **bh, loff_t *i_pos)
1151 {
1152 	struct super_block *sb = dir->i_sb;
1153 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
1154 	struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1155 	sector_t blknr, start_blknr, last_blknr;
1156 	unsigned long size, copy;
1157 	int err, i, n, offset, cluster[2];
1158 
1159 	/*
1160 	 * The minimum cluster size is 512bytes, and maximum entry
1161 	 * size is 32*slots (672bytes).  So, iff the cluster size is
1162 	 * 512bytes, we may need two clusters.
1163 	 */
1164 	size = nr_slots * sizeof(struct msdos_dir_entry);
1165 	*nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits;
1166 	BUG_ON(*nr_cluster > 2);
1167 
1168 	err = fat_alloc_clusters(dir, cluster, *nr_cluster);
1169 	if (err)
1170 		goto error;
1171 
1172 	/*
1173 	 * First stage: Fill the directory entry.  NOTE: This cluster
1174 	 * is not referenced from any inode yet, so updates order is
1175 	 * not important.
1176 	 */
1177 	i = n = copy = 0;
1178 	do {
1179 		start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]);
1180 		last_blknr = start_blknr + sbi->sec_per_clus;
1181 		while (blknr < last_blknr) {
1182 			bhs[n] = sb_getblk(sb, blknr);
1183 			if (!bhs[n]) {
1184 				err = -ENOMEM;
1185 				goto error_nomem;
1186 			}
1187 
1188 			/* fill the directory entry */
1189 			copy = min(size, sb->s_blocksize);
1190 			memcpy(bhs[n]->b_data, slots, copy);
1191 			slots += copy;
1192 			size -= copy;
1193 			set_buffer_uptodate(bhs[n]);
1194 			mark_buffer_dirty_inode(bhs[n], dir);
1195 			if (!size)
1196 				break;
1197 			n++;
1198 			blknr++;
1199 		}
1200 	} while (++i < *nr_cluster);
1201 
1202 	memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy);
1203 	offset = copy - sizeof(struct msdos_dir_entry);
1204 	get_bh(bhs[n]);
1205 	*bh = bhs[n];
1206 	*de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
1207 	*i_pos = fat_make_i_pos(sb, *bh, *de);
1208 
1209 	/* Second stage: clear the rest of cluster, and write outs */
1210 	err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE);
1211 	if (err)
1212 		goto error_free;
1213 
1214 	return cluster[0];
1215 
1216 error_free:
1217 	brelse(*bh);
1218 	*bh = NULL;
1219 	n = 0;
1220 error_nomem:
1221 	for (i = 0; i < n; i++)
1222 		bforget(bhs[i]);
1223 	fat_free_clusters(dir, cluster[0]);
1224 error:
1225 	return err;
1226 }
1227 
1228 int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
1229 		    struct fat_slot_info *sinfo)
1230 {
1231 	struct super_block *sb = dir->i_sb;
1232 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
1233 	struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */
1234 	struct msdos_dir_entry *de;
1235 	int err, free_slots, i, nr_bhs;
1236 	loff_t pos, i_pos;
1237 
1238 	sinfo->nr_slots = nr_slots;
1239 
1240 	/* First stage: search free direcotry entries */
1241 	free_slots = nr_bhs = 0;
1242 	bh = prev = NULL;
1243 	pos = 0;
1244 	err = -ENOSPC;
1245 	while (fat_get_entry(dir, &pos, &bh, &de) > -1) {
1246 		/* check the maximum size of directory */
1247 		if (pos >= FAT_MAX_DIR_SIZE)
1248 			goto error;
1249 
1250 		if (IS_FREE(de->name)) {
1251 			if (prev != bh) {
1252 				get_bh(bh);
1253 				bhs[nr_bhs] = prev = bh;
1254 				nr_bhs++;
1255 			}
1256 			free_slots++;
1257 			if (free_slots == nr_slots)
1258 				goto found;
1259 		} else {
1260 			for (i = 0; i < nr_bhs; i++)
1261 				brelse(bhs[i]);
1262 			prev = NULL;
1263 			free_slots = nr_bhs = 0;
1264 		}
1265 	}
1266 	if (dir->i_ino == MSDOS_ROOT_INO) {
1267 		if (sbi->fat_bits != 32)
1268 			goto error;
1269 	} else if (MSDOS_I(dir)->i_start == 0) {
1270 		fat_msg(sb, KERN_ERR, "Corrupted directory (i_pos %lld)",
1271 		       MSDOS_I(dir)->i_pos);
1272 		err = -EIO;
1273 		goto error;
1274 	}
1275 
1276 found:
1277 	err = 0;
1278 	pos -= free_slots * sizeof(*de);
1279 	nr_slots -= free_slots;
1280 	if (free_slots) {
1281 		/*
1282 		 * Second stage: filling the free entries with new entries.
1283 		 * NOTE: If this slots has shortname, first, we write
1284 		 * the long name slots, then write the short name.
1285 		 */
1286 		int size = free_slots * sizeof(*de);
1287 		int offset = pos & (sb->s_blocksize - 1);
1288 		int long_bhs = nr_bhs - (nr_slots == 0);
1289 
1290 		/* Fill the long name slots. */
1291 		for (i = 0; i < long_bhs; i++) {
1292 			int copy = min_t(int, sb->s_blocksize - offset, size);
1293 			memcpy(bhs[i]->b_data + offset, slots, copy);
1294 			mark_buffer_dirty_inode(bhs[i], dir);
1295 			offset = 0;
1296 			slots += copy;
1297 			size -= copy;
1298 		}
1299 		if (long_bhs && IS_DIRSYNC(dir))
1300 			err = fat_sync_bhs(bhs, long_bhs);
1301 		if (!err && i < nr_bhs) {
1302 			/* Fill the short name slot. */
1303 			int copy = min_t(int, sb->s_blocksize - offset, size);
1304 			memcpy(bhs[i]->b_data + offset, slots, copy);
1305 			mark_buffer_dirty_inode(bhs[i], dir);
1306 			if (IS_DIRSYNC(dir))
1307 				err = sync_dirty_buffer(bhs[i]);
1308 		}
1309 		for (i = 0; i < nr_bhs; i++)
1310 			brelse(bhs[i]);
1311 		if (err)
1312 			goto error_remove;
1313 	}
1314 
1315 	if (nr_slots) {
1316 		int cluster, nr_cluster;
1317 
1318 		/*
1319 		 * Third stage: allocate the cluster for new entries.
1320 		 * And initialize the cluster with new entries, then
1321 		 * add the cluster to dir.
1322 		 */
1323 		cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster,
1324 					      &de, &bh, &i_pos);
1325 		if (cluster < 0) {
1326 			err = cluster;
1327 			goto error_remove;
1328 		}
1329 		err = fat_chain_add(dir, cluster, nr_cluster);
1330 		if (err) {
1331 			fat_free_clusters(dir, cluster);
1332 			goto error_remove;
1333 		}
1334 		if (dir->i_size & (sbi->cluster_size - 1)) {
1335 			fat_fs_error(sb, "Odd directory size");
1336 			dir->i_size = (dir->i_size + sbi->cluster_size - 1)
1337 				& ~((loff_t)sbi->cluster_size - 1);
1338 		}
1339 		dir->i_size += nr_cluster << sbi->cluster_bits;
1340 		MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits;
1341 	}
1342 	sinfo->slot_off = pos;
1343 	sinfo->de = de;
1344 	sinfo->bh = bh;
1345 	sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
1346 
1347 	return 0;
1348 
1349 error:
1350 	brelse(bh);
1351 	for (i = 0; i < nr_bhs; i++)
1352 		brelse(bhs[i]);
1353 	return err;
1354 
1355 error_remove:
1356 	brelse(bh);
1357 	if (free_slots)
1358 		__fat_remove_entries(dir, pos, free_slots);
1359 	return err;
1360 }
1361 
1362 EXPORT_SYMBOL_GPL(fat_add_entries);
1363