xref: /linux/fs/fat/dir.c (revision 529d6dad5bc69de14cdd24831e2a14264e93daa4)
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 		printk(KERN_ERR "FAT: Directory bread(block %llu) failed\n",
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(unsigned char *ascii, const wchar_t *uni, int len,
140 		       int uni_xlate, struct nls_table *nls)
141 {
142 	const wchar_t *ip;
143 	wchar_t ec;
144 	unsigned char *op;
145 	int charlen;
146 
147 	ip = uni;
148 	op = ascii;
149 
150 	while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {
151 		ec = *ip++;
152 		if ((charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE)) > 0) {
153 			op += charlen;
154 			len -= charlen;
155 		} else {
156 			if (uni_xlate == 1) {
157 				*op++ = ':';
158 				op = pack_hex_byte(op, ec >> 8);
159 				op = pack_hex_byte(op, ec);
160 				len -= 5;
161 			} else {
162 				*op++ = '?';
163 				len--;
164 			}
165 		}
166 	}
167 
168 	if (unlikely(*ip)) {
169 		printk(KERN_WARNING "FAT: filename was truncated while "
170 		       "converting.");
171 	}
172 
173 	*op = 0;
174 	return (op - ascii);
175 }
176 
177 static inline int fat_uni_to_x8(struct msdos_sb_info *sbi, const wchar_t *uni,
178 				unsigned char *buf, int size)
179 {
180 	if (sbi->options.utf8)
181 		return utf16s_to_utf8s(uni, FAT_MAX_UNI_CHARS,
182 				UTF16_HOST_ENDIAN, buf, size);
183 	else
184 		return uni16_to_x8(buf, uni, size, sbi->options.unicode_xlate,
185 				   sbi->nls_io);
186 }
187 
188 static inline int
189 fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
190 {
191 	int charlen;
192 
193 	charlen = t->char2uni(c, clen, uni);
194 	if (charlen < 0) {
195 		*uni = 0x003f;	/* a question mark */
196 		charlen = 1;
197 	}
198 	return charlen;
199 }
200 
201 static inline int
202 fat_short2lower_uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
203 {
204 	int charlen;
205 	wchar_t wc;
206 
207 	charlen = t->char2uni(c, clen, &wc);
208 	if (charlen < 0) {
209 		*uni = 0x003f;	/* a question mark */
210 		charlen = 1;
211 	} else if (charlen <= 1) {
212 		unsigned char nc = t->charset2lower[*c];
213 
214 		if (!nc)
215 			nc = *c;
216 
217 		if ( (charlen = t->char2uni(&nc, 1, uni)) < 0) {
218 			*uni = 0x003f;	/* a question mark */
219 			charlen = 1;
220 		}
221 	} else
222 		*uni = wc;
223 
224 	return charlen;
225 }
226 
227 static inline int
228 fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size,
229 		  wchar_t *uni_buf, unsigned short opt, int lower)
230 {
231 	int len = 0;
232 
233 	if (opt & VFAT_SFN_DISPLAY_LOWER)
234 		len =  fat_short2lower_uni(nls, buf, buf_size, uni_buf);
235 	else if (opt & VFAT_SFN_DISPLAY_WIN95)
236 		len = fat_short2uni(nls, buf, buf_size, uni_buf);
237 	else if (opt & VFAT_SFN_DISPLAY_WINNT) {
238 		if (lower)
239 			len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
240 		else
241 			len = fat_short2uni(nls, buf, buf_size, uni_buf);
242 	} else
243 		len = fat_short2uni(nls, buf, buf_size, uni_buf);
244 
245 	return len;
246 }
247 
248 static inline int fat_name_match(struct msdos_sb_info *sbi,
249 				 const unsigned char *a, int a_len,
250 				 const unsigned char *b, int b_len)
251 {
252 	if (a_len != b_len)
253 		return 0;
254 
255 	if (sbi->options.name_check != 's')
256 		return !nls_strnicmp(sbi->nls_io, a, b, a_len);
257 	else
258 		return !memcmp(a, b, a_len);
259 }
260 
261 enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, };
262 
263 /**
264  * fat_parse_long - Parse extended directory entry.
265  *
266  * This function returns zero on success, negative value on error, or one of
267  * the following:
268  *
269  * %PARSE_INVALID - Directory entry is invalid.
270  * %PARSE_NOT_LONGNAME - Directory entry does not contain longname.
271  * %PARSE_EOF - Directory has no more entries.
272  */
273 static int fat_parse_long(struct inode *dir, loff_t *pos,
274 			  struct buffer_head **bh, struct msdos_dir_entry **de,
275 			  wchar_t **unicode, unsigned char *nr_slots)
276 {
277 	struct msdos_dir_slot *ds;
278 	unsigned char id, slot, slots, alias_checksum;
279 
280 	if (!*unicode) {
281 		*unicode = __getname();
282 		if (!*unicode) {
283 			brelse(*bh);
284 			return -ENOMEM;
285 		}
286 	}
287 parse_long:
288 	slots = 0;
289 	ds = (struct msdos_dir_slot *)*de;
290 	id = ds->id;
291 	if (!(id & 0x40))
292 		return PARSE_INVALID;
293 	slots = id & ~0x40;
294 	if (slots > 20 || !slots)	/* ceil(256 * 2 / 26) */
295 		return PARSE_INVALID;
296 	*nr_slots = slots;
297 	alias_checksum = ds->alias_checksum;
298 
299 	slot = slots;
300 	while (1) {
301 		int offset;
302 
303 		slot--;
304 		offset = slot * 13;
305 		fat16_towchar(*unicode + offset, ds->name0_4, 5);
306 		fat16_towchar(*unicode + offset + 5, ds->name5_10, 6);
307 		fat16_towchar(*unicode + offset + 11, ds->name11_12, 2);
308 
309 		if (ds->id & 0x40)
310 			(*unicode)[offset + 13] = 0;
311 		if (fat_get_entry(dir, pos, bh, de) < 0)
312 			return PARSE_EOF;
313 		if (slot == 0)
314 			break;
315 		ds = (struct msdos_dir_slot *)*de;
316 		if (ds->attr != ATTR_EXT)
317 			return PARSE_NOT_LONGNAME;
318 		if ((ds->id & ~0x40) != slot)
319 			goto parse_long;
320 		if (ds->alias_checksum != alias_checksum)
321 			goto parse_long;
322 	}
323 	if ((*de)->name[0] == DELETED_FLAG)
324 		return PARSE_INVALID;
325 	if ((*de)->attr == ATTR_EXT)
326 		goto parse_long;
327 	if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME))
328 		return PARSE_INVALID;
329 	if (fat_checksum((*de)->name) != alias_checksum)
330 		*nr_slots = 0;
331 
332 	return 0;
333 }
334 
335 /*
336  * Return values: negative -> error, 0 -> not found, positive -> found,
337  * value is the total amount of slots, including the shortname entry.
338  */
339 int fat_search_long(struct inode *inode, const unsigned char *name,
340 		    int name_len, struct fat_slot_info *sinfo)
341 {
342 	struct super_block *sb = inode->i_sb;
343 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
344 	struct buffer_head *bh = NULL;
345 	struct msdos_dir_entry *de;
346 	struct nls_table *nls_disk = sbi->nls_disk;
347 	unsigned char nr_slots;
348 	wchar_t bufuname[14];
349 	wchar_t *unicode = NULL;
350 	unsigned char work[MSDOS_NAME];
351 	unsigned char bufname[FAT_MAX_SHORT_SIZE];
352 	unsigned short opt_shortname = sbi->options.shortname;
353 	loff_t cpos = 0;
354 	int chl, i, j, last_u, err, len;
355 
356 	err = -ENOENT;
357 	while (1) {
358 		if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
359 			goto end_of_dir;
360 parse_record:
361 		nr_slots = 0;
362 		if (de->name[0] == DELETED_FLAG)
363 			continue;
364 		if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
365 			continue;
366 		if (de->attr != ATTR_EXT && IS_FREE(de->name))
367 			continue;
368 		if (de->attr == ATTR_EXT) {
369 			int status = fat_parse_long(inode, &cpos, &bh, &de,
370 						    &unicode, &nr_slots);
371 			if (status < 0) {
372 				err = status;
373 				goto end_of_dir;
374 			} else if (status == PARSE_INVALID)
375 				continue;
376 			else if (status == PARSE_NOT_LONGNAME)
377 				goto parse_record;
378 			else if (status == PARSE_EOF)
379 				goto end_of_dir;
380 		}
381 
382 		memcpy(work, de->name, sizeof(de->name));
383 		/* see namei.c, msdos_format_name */
384 		if (work[0] == 0x05)
385 			work[0] = 0xE5;
386 		for (i = 0, j = 0, last_u = 0; i < 8;) {
387 			if (!work[i])
388 				break;
389 			chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
390 						&bufuname[j++], opt_shortname,
391 						de->lcase & CASE_LOWER_BASE);
392 			if (chl <= 1) {
393 				if (work[i] != ' ')
394 					last_u = j;
395 			} else {
396 				last_u = j;
397 			}
398 			i += chl;
399 		}
400 		j = last_u;
401 		fat_short2uni(nls_disk, ".", 1, &bufuname[j++]);
402 		for (i = 8; i < MSDOS_NAME;) {
403 			if (!work[i])
404 				break;
405 			chl = fat_shortname2uni(nls_disk, &work[i],
406 						MSDOS_NAME - i,
407 						&bufuname[j++], opt_shortname,
408 						de->lcase & CASE_LOWER_EXT);
409 			if (chl <= 1) {
410 				if (work[i] != ' ')
411 					last_u = j;
412 			} else {
413 				last_u = j;
414 			}
415 			i += chl;
416 		}
417 		if (!last_u)
418 			continue;
419 
420 		/* Compare shortname */
421 		bufuname[last_u] = 0x0000;
422 		len = fat_uni_to_x8(sbi, bufuname, bufname, sizeof(bufname));
423 		if (fat_name_match(sbi, name, name_len, bufname, len))
424 			goto found;
425 
426 		if (nr_slots) {
427 			void *longname = unicode + FAT_MAX_UNI_CHARS;
428 			int size = PATH_MAX - FAT_MAX_UNI_SIZE;
429 
430 			/* Compare longname */
431 			len = fat_uni_to_x8(sbi, unicode, longname, size);
432 			if (fat_name_match(sbi, name, name_len, longname, len))
433 				goto found;
434 		}
435 	}
436 
437 found:
438 	nr_slots++;	/* include the de */
439 	sinfo->slot_off = cpos - nr_slots * sizeof(*de);
440 	sinfo->nr_slots = nr_slots;
441 	sinfo->de = de;
442 	sinfo->bh = bh;
443 	sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
444 	err = 0;
445 end_of_dir:
446 	if (unicode)
447 		__putname(unicode);
448 
449 	return err;
450 }
451 
452 EXPORT_SYMBOL_GPL(fat_search_long);
453 
454 struct fat_ioctl_filldir_callback {
455 	void __user *dirent;
456 	int result;
457 	/* for dir ioctl */
458 	const char *longname;
459 	int long_len;
460 	const char *shortname;
461 	int short_len;
462 };
463 
464 static int __fat_readdir(struct inode *inode, struct file *filp, void *dirent,
465 			 filldir_t filldir, int short_only, int both)
466 {
467 	struct super_block *sb = inode->i_sb;
468 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
469 	struct buffer_head *bh;
470 	struct msdos_dir_entry *de;
471 	struct nls_table *nls_disk = sbi->nls_disk;
472 	unsigned char nr_slots;
473 	wchar_t bufuname[14];
474 	wchar_t *unicode = NULL;
475 	unsigned char c, work[MSDOS_NAME];
476 	unsigned char bufname[FAT_MAX_SHORT_SIZE], *ptname = bufname;
477 	unsigned short opt_shortname = sbi->options.shortname;
478 	int isvfat = sbi->options.isvfat;
479 	int nocase = sbi->options.nocase;
480 	const char *fill_name = NULL;
481 	unsigned long inum;
482 	unsigned long lpos, dummy, *furrfu = &lpos;
483 	loff_t cpos;
484 	int chi, chl, i, i2, j, last, last_u, dotoffset = 0, fill_len = 0;
485 	int ret = 0;
486 
487 	lock_super(sb);
488 
489 	cpos = filp->f_pos;
490 	/* Fake . and .. for the root directory. */
491 	if (inode->i_ino == MSDOS_ROOT_INO) {
492 		while (cpos < 2) {
493 			if (filldir(dirent, "..", cpos+1, cpos, MSDOS_ROOT_INO, DT_DIR) < 0)
494 				goto out;
495 			cpos++;
496 			filp->f_pos++;
497 		}
498 		if (cpos == 2) {
499 			dummy = 2;
500 			furrfu = &dummy;
501 			cpos = 0;
502 		}
503 	}
504 	if (cpos & (sizeof(struct msdos_dir_entry) - 1)) {
505 		ret = -ENOENT;
506 		goto out;
507 	}
508 
509 	bh = NULL;
510 get_new:
511 	if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
512 		goto end_of_dir;
513 parse_record:
514 	nr_slots = 0;
515 	/*
516 	 * Check for long filename entry, but if short_only, we don't
517 	 * need to parse long filename.
518 	 */
519 	if (isvfat && !short_only) {
520 		if (de->name[0] == DELETED_FLAG)
521 			goto record_end;
522 		if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
523 			goto record_end;
524 		if (de->attr != ATTR_EXT && IS_FREE(de->name))
525 			goto record_end;
526 	} else {
527 		if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))
528 			goto record_end;
529 	}
530 
531 	if (isvfat && de->attr == ATTR_EXT) {
532 		int status = fat_parse_long(inode, &cpos, &bh, &de,
533 					    &unicode, &nr_slots);
534 		if (status < 0) {
535 			filp->f_pos = cpos;
536 			ret = status;
537 			goto out;
538 		} else if (status == PARSE_INVALID)
539 			goto record_end;
540 		else if (status == PARSE_NOT_LONGNAME)
541 			goto parse_record;
542 		else if (status == PARSE_EOF)
543 			goto end_of_dir;
544 
545 		if (nr_slots) {
546 			void *longname = unicode + FAT_MAX_UNI_CHARS;
547 			int size = PATH_MAX - FAT_MAX_UNI_SIZE;
548 			int len = fat_uni_to_x8(sbi, unicode, longname, size);
549 
550 			fill_name = longname;
551 			fill_len = len;
552 			/* !both && !short_only, so we don't need shortname. */
553 			if (!both)
554 				goto start_filldir;
555 		}
556 	}
557 
558 	if (sbi->options.dotsOK) {
559 		ptname = bufname;
560 		dotoffset = 0;
561 		if (de->attr & ATTR_HIDDEN) {
562 			*ptname++ = '.';
563 			dotoffset = 1;
564 		}
565 	}
566 
567 	memcpy(work, de->name, sizeof(de->name));
568 	/* see namei.c, msdos_format_name */
569 	if (work[0] == 0x05)
570 		work[0] = 0xE5;
571 	for (i = 0, j = 0, last = 0, last_u = 0; i < 8;) {
572 		if (!(c = work[i]))
573 			break;
574 		chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
575 					&bufuname[j++], opt_shortname,
576 					de->lcase & CASE_LOWER_BASE);
577 		if (chl <= 1) {
578 			ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c;
579 			if (c != ' ') {
580 				last = i;
581 				last_u = j;
582 			}
583 		} else {
584 			last_u = j;
585 			for (chi = 0; chi < chl && i < 8; chi++) {
586 				ptname[i] = work[i];
587 				i++; last = i;
588 			}
589 		}
590 	}
591 	i = last;
592 	j = last_u;
593 	fat_short2uni(nls_disk, ".", 1, &bufuname[j++]);
594 	ptname[i++] = '.';
595 	for (i2 = 8; i2 < MSDOS_NAME;) {
596 		if (!(c = work[i2]))
597 			break;
598 		chl = fat_shortname2uni(nls_disk, &work[i2], MSDOS_NAME - i2,
599 					&bufuname[j++], opt_shortname,
600 					de->lcase & CASE_LOWER_EXT);
601 		if (chl <= 1) {
602 			i2++;
603 			ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c;
604 			if (c != ' ') {
605 				last = i;
606 				last_u = j;
607 			}
608 		} else {
609 			last_u = j;
610 			for (chi = 0; chi < chl && i2 < MSDOS_NAME; chi++) {
611 				ptname[i++] = work[i2++];
612 				last = i;
613 			}
614 		}
615 	}
616 	if (!last)
617 		goto record_end;
618 
619 	i = last + dotoffset;
620 	j = last_u;
621 
622 	if (isvfat) {
623 		bufuname[j] = 0x0000;
624 		i = fat_uni_to_x8(sbi, bufuname, bufname, sizeof(bufname));
625 	}
626 	if (nr_slots) {
627 		/* hack for fat_ioctl_filldir() */
628 		struct fat_ioctl_filldir_callback *p = dirent;
629 
630 		p->longname = fill_name;
631 		p->long_len = fill_len;
632 		p->shortname = bufname;
633 		p->short_len = i;
634 		fill_name = NULL;
635 		fill_len = 0;
636 	} else {
637 		fill_name = bufname;
638 		fill_len = i;
639 	}
640 
641 start_filldir:
642 	lpos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
643 	if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME))
644 		inum = inode->i_ino;
645 	else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
646 		inum = parent_ino(filp->f_path.dentry);
647 	} else {
648 		loff_t i_pos = fat_make_i_pos(sb, bh, de);
649 		struct inode *tmp = fat_iget(sb, i_pos);
650 		if (tmp) {
651 			inum = tmp->i_ino;
652 			iput(tmp);
653 		} else
654 			inum = iunique(sb, MSDOS_ROOT_INO);
655 	}
656 
657 	if (filldir(dirent, fill_name, fill_len, *furrfu, inum,
658 		    (de->attr & ATTR_DIR) ? DT_DIR : DT_REG) < 0)
659 		goto fill_failed;
660 
661 record_end:
662 	furrfu = &lpos;
663 	filp->f_pos = cpos;
664 	goto get_new;
665 end_of_dir:
666 	filp->f_pos = cpos;
667 fill_failed:
668 	brelse(bh);
669 	if (unicode)
670 		__putname(unicode);
671 out:
672 	unlock_super(sb);
673 	return ret;
674 }
675 
676 static int fat_readdir(struct file *filp, void *dirent, filldir_t filldir)
677 {
678 	struct inode *inode = filp->f_path.dentry->d_inode;
679 	return __fat_readdir(inode, filp, dirent, filldir, 0, 0);
680 }
681 
682 #define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type)			   \
683 static int func(void *__buf, const char *name, int name_len,		   \
684 			     loff_t offset, u64 ino, unsigned int d_type)  \
685 {									   \
686 	struct fat_ioctl_filldir_callback *buf = __buf;			   \
687 	struct dirent_type __user *d1 = buf->dirent;			   \
688 	struct dirent_type __user *d2 = d1 + 1;				   \
689 									   \
690 	if (buf->result)						   \
691 		return -EINVAL;						   \
692 	buf->result++;							   \
693 									   \
694 	if (name != NULL) {						   \
695 		/* dirent has only short name */			   \
696 		if (name_len >= sizeof(d1->d_name))			   \
697 			name_len = sizeof(d1->d_name) - 1;		   \
698 									   \
699 		if (put_user(0, d2->d_name)			||	   \
700 		    put_user(0, &d2->d_reclen)			||	   \
701 		    copy_to_user(d1->d_name, name, name_len)	||	   \
702 		    put_user(0, d1->d_name + name_len)		||	   \
703 		    put_user(name_len, &d1->d_reclen))			   \
704 			goto efault;					   \
705 	} else {							   \
706 		/* dirent has short and long name */			   \
707 		const char *longname = buf->longname;			   \
708 		int long_len = buf->long_len;				   \
709 		const char *shortname = buf->shortname;			   \
710 		int short_len = buf->short_len;				   \
711 									   \
712 		if (long_len >= sizeof(d1->d_name))			   \
713 			long_len = sizeof(d1->d_name) - 1;		   \
714 		if (short_len >= sizeof(d1->d_name))			   \
715 			short_len = sizeof(d1->d_name) - 1;		   \
716 									   \
717 		if (copy_to_user(d2->d_name, longname, long_len)	|| \
718 		    put_user(0, d2->d_name + long_len)			|| \
719 		    put_user(long_len, &d2->d_reclen)			|| \
720 		    put_user(ino, &d2->d_ino)				|| \
721 		    put_user(offset, &d2->d_off)			|| \
722 		    copy_to_user(d1->d_name, shortname, short_len)	|| \
723 		    put_user(0, d1->d_name + short_len)			|| \
724 		    put_user(short_len, &d1->d_reclen))			   \
725 			goto efault;					   \
726 	}								   \
727 	return 0;							   \
728 efault:									   \
729 	buf->result = -EFAULT;						   \
730 	return -EFAULT;							   \
731 }
732 
733 FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)
734 
735 static int fat_ioctl_readdir(struct inode *inode, struct file *filp,
736 			     void __user *dirent, filldir_t filldir,
737 			     int short_only, int both)
738 {
739 	struct fat_ioctl_filldir_callback buf;
740 	int ret;
741 
742 	buf.dirent = dirent;
743 	buf.result = 0;
744 	mutex_lock(&inode->i_mutex);
745 	ret = -ENOENT;
746 	if (!IS_DEADDIR(inode)) {
747 		ret = __fat_readdir(inode, filp, &buf, filldir,
748 				    short_only, both);
749 	}
750 	mutex_unlock(&inode->i_mutex);
751 	if (ret >= 0)
752 		ret = buf.result;
753 	return ret;
754 }
755 
756 static long fat_dir_ioctl(struct file *filp, unsigned int cmd,
757 			  unsigned long arg)
758 {
759 	struct inode *inode = filp->f_path.dentry->d_inode;
760 	struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg;
761 	int short_only, both;
762 
763 	switch (cmd) {
764 	case VFAT_IOCTL_READDIR_SHORT:
765 		short_only = 1;
766 		both = 0;
767 		break;
768 	case VFAT_IOCTL_READDIR_BOTH:
769 		short_only = 0;
770 		both = 1;
771 		break;
772 	default:
773 		return fat_generic_ioctl(filp, cmd, arg);
774 	}
775 
776 	if (!access_ok(VERIFY_WRITE, d1, sizeof(struct __fat_dirent[2])))
777 		return -EFAULT;
778 	/*
779 	 * Yes, we don't need this put_user() absolutely. However old
780 	 * code didn't return the right value. So, app use this value,
781 	 * in order to check whether it is EOF.
782 	 */
783 	if (put_user(0, &d1->d_reclen))
784 		return -EFAULT;
785 
786 	return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir,
787 				 short_only, both);
788 }
789 
790 #ifdef CONFIG_COMPAT
791 #define	VFAT_IOCTL_READDIR_BOTH32	_IOR('r', 1, struct compat_dirent[2])
792 #define	VFAT_IOCTL_READDIR_SHORT32	_IOR('r', 2, struct compat_dirent[2])
793 
794 FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent)
795 
796 static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd,
797 				 unsigned long arg)
798 {
799 	struct inode *inode = filp->f_path.dentry->d_inode;
800 	struct compat_dirent __user *d1 = compat_ptr(arg);
801 	int short_only, both;
802 
803 	switch (cmd) {
804 	case VFAT_IOCTL_READDIR_SHORT32:
805 		short_only = 1;
806 		both = 0;
807 		break;
808 	case VFAT_IOCTL_READDIR_BOTH32:
809 		short_only = 0;
810 		both = 1;
811 		break;
812 	default:
813 		return fat_generic_ioctl(filp, cmd, (unsigned long)arg);
814 	}
815 
816 	if (!access_ok(VERIFY_WRITE, d1, sizeof(struct compat_dirent[2])))
817 		return -EFAULT;
818 	/*
819 	 * Yes, we don't need this put_user() absolutely. However old
820 	 * code didn't return the right value. So, app use this value,
821 	 * in order to check whether it is EOF.
822 	 */
823 	if (put_user(0, &d1->d_reclen))
824 		return -EFAULT;
825 
826 	return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir,
827 				 short_only, both);
828 }
829 #endif /* CONFIG_COMPAT */
830 
831 const struct file_operations fat_dir_operations = {
832 	.llseek		= generic_file_llseek,
833 	.read		= generic_read_dir,
834 	.readdir	= fat_readdir,
835 	.unlocked_ioctl	= fat_dir_ioctl,
836 #ifdef CONFIG_COMPAT
837 	.compat_ioctl	= fat_compat_dir_ioctl,
838 #endif
839 	.fsync		= fat_file_fsync,
840 };
841 
842 static int fat_get_short_entry(struct inode *dir, loff_t *pos,
843 			       struct buffer_head **bh,
844 			       struct msdos_dir_entry **de)
845 {
846 	while (fat_get_entry(dir, pos, bh, de) >= 0) {
847 		/* free entry or long name entry or volume label */
848 		if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))
849 			return 0;
850 	}
851 	return -ENOENT;
852 }
853 
854 /*
855  * The ".." entry can not provide the "struct fat_slot_info" informations
856  * for inode. So, this function provide the some informations only.
857  */
858 int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
859 			 struct msdos_dir_entry **de, loff_t *i_pos)
860 {
861 	loff_t offset;
862 
863 	offset = 0;
864 	*bh = NULL;
865 	while (fat_get_short_entry(dir, &offset, bh, de) >= 0) {
866 		if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME)) {
867 			*i_pos = fat_make_i_pos(dir->i_sb, *bh, *de);
868 			return 0;
869 		}
870 	}
871 	return -ENOENT;
872 }
873 
874 EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);
875 
876 /* See if directory is empty */
877 int fat_dir_empty(struct inode *dir)
878 {
879 	struct buffer_head *bh;
880 	struct msdos_dir_entry *de;
881 	loff_t cpos;
882 	int result = 0;
883 
884 	bh = NULL;
885 	cpos = 0;
886 	while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
887 		if (strncmp(de->name, MSDOS_DOT   , MSDOS_NAME) &&
888 		    strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
889 			result = -ENOTEMPTY;
890 			break;
891 		}
892 	}
893 	brelse(bh);
894 	return result;
895 }
896 
897 EXPORT_SYMBOL_GPL(fat_dir_empty);
898 
899 /*
900  * fat_subdirs counts the number of sub-directories of dir. It can be run
901  * on directories being created.
902  */
903 int fat_subdirs(struct inode *dir)
904 {
905 	struct buffer_head *bh;
906 	struct msdos_dir_entry *de;
907 	loff_t cpos;
908 	int count = 0;
909 
910 	bh = NULL;
911 	cpos = 0;
912 	while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
913 		if (de->attr & ATTR_DIR)
914 			count++;
915 	}
916 	brelse(bh);
917 	return count;
918 }
919 
920 /*
921  * Scans a directory for a given file (name points to its formatted name).
922  * Returns an error code or zero.
923  */
924 int fat_scan(struct inode *dir, const unsigned char *name,
925 	     struct fat_slot_info *sinfo)
926 {
927 	struct super_block *sb = dir->i_sb;
928 
929 	sinfo->slot_off = 0;
930 	sinfo->bh = NULL;
931 	while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
932 				   &sinfo->de) >= 0) {
933 		if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) {
934 			sinfo->slot_off -= sizeof(*sinfo->de);
935 			sinfo->nr_slots = 1;
936 			sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
937 			return 0;
938 		}
939 	}
940 	return -ENOENT;
941 }
942 
943 EXPORT_SYMBOL_GPL(fat_scan);
944 
945 static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)
946 {
947 	struct super_block *sb = dir->i_sb;
948 	struct buffer_head *bh;
949 	struct msdos_dir_entry *de, *endp;
950 	int err = 0, orig_slots;
951 
952 	while (nr_slots) {
953 		bh = NULL;
954 		if (fat_get_entry(dir, &pos, &bh, &de) < 0) {
955 			err = -EIO;
956 			break;
957 		}
958 
959 		orig_slots = nr_slots;
960 		endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize);
961 		while (nr_slots && de < endp) {
962 			de->name[0] = DELETED_FLAG;
963 			de++;
964 			nr_slots--;
965 		}
966 		mark_buffer_dirty_inode(bh, dir);
967 		if (IS_DIRSYNC(dir))
968 			err = sync_dirty_buffer(bh);
969 		brelse(bh);
970 		if (err)
971 			break;
972 
973 		/* pos is *next* de's position, so this does `- sizeof(de)' */
974 		pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de);
975 	}
976 
977 	return err;
978 }
979 
980 int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)
981 {
982 	struct msdos_dir_entry *de;
983 	struct buffer_head *bh;
984 	int err = 0, nr_slots;
985 
986 	/*
987 	 * First stage: Remove the shortname. By this, the directory
988 	 * entry is removed.
989 	 */
990 	nr_slots = sinfo->nr_slots;
991 	de = sinfo->de;
992 	sinfo->de = NULL;
993 	bh = sinfo->bh;
994 	sinfo->bh = NULL;
995 	while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) {
996 		de->name[0] = DELETED_FLAG;
997 		de--;
998 		nr_slots--;
999 	}
1000 	mark_buffer_dirty_inode(bh, dir);
1001 	if (IS_DIRSYNC(dir))
1002 		err = sync_dirty_buffer(bh);
1003 	brelse(bh);
1004 	if (err)
1005 		return err;
1006 	dir->i_version++;
1007 
1008 	if (nr_slots) {
1009 		/*
1010 		 * Second stage: remove the remaining longname slots.
1011 		 * (This directory entry is already removed, and so return
1012 		 * the success)
1013 		 */
1014 		err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots);
1015 		if (err) {
1016 			printk(KERN_WARNING
1017 			       "FAT: Couldn't remove the long name slots\n");
1018 		}
1019 	}
1020 
1021 	dir->i_mtime = dir->i_atime = CURRENT_TIME_SEC;
1022 	if (IS_DIRSYNC(dir))
1023 		(void)fat_sync_inode(dir);
1024 	else
1025 		mark_inode_dirty(dir);
1026 
1027 	return 0;
1028 }
1029 
1030 EXPORT_SYMBOL_GPL(fat_remove_entries);
1031 
1032 static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,
1033 			      struct buffer_head **bhs, int nr_bhs)
1034 {
1035 	struct super_block *sb = dir->i_sb;
1036 	sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus;
1037 	int err, i, n;
1038 
1039 	/* Zeroing the unused blocks on this cluster */
1040 	blknr += nr_used;
1041 	n = nr_used;
1042 	while (blknr < last_blknr) {
1043 		bhs[n] = sb_getblk(sb, blknr);
1044 		if (!bhs[n]) {
1045 			err = -ENOMEM;
1046 			goto error;
1047 		}
1048 		memset(bhs[n]->b_data, 0, sb->s_blocksize);
1049 		set_buffer_uptodate(bhs[n]);
1050 		mark_buffer_dirty_inode(bhs[n], dir);
1051 
1052 		n++;
1053 		blknr++;
1054 		if (n == nr_bhs) {
1055 			if (IS_DIRSYNC(dir)) {
1056 				err = fat_sync_bhs(bhs, n);
1057 				if (err)
1058 					goto error;
1059 			}
1060 			for (i = 0; i < n; i++)
1061 				brelse(bhs[i]);
1062 			n = 0;
1063 		}
1064 	}
1065 	if (IS_DIRSYNC(dir)) {
1066 		err = fat_sync_bhs(bhs, n);
1067 		if (err)
1068 			goto error;
1069 	}
1070 	for (i = 0; i < n; i++)
1071 		brelse(bhs[i]);
1072 
1073 	return 0;
1074 
1075 error:
1076 	for (i = 0; i < n; i++)
1077 		bforget(bhs[i]);
1078 	return err;
1079 }
1080 
1081 int fat_alloc_new_dir(struct inode *dir, struct timespec *ts)
1082 {
1083 	struct super_block *sb = dir->i_sb;
1084 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
1085 	struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1086 	struct msdos_dir_entry *de;
1087 	sector_t blknr;
1088 	__le16 date, time;
1089 	u8 time_cs;
1090 	int err, cluster;
1091 
1092 	err = fat_alloc_clusters(dir, &cluster, 1);
1093 	if (err)
1094 		goto error;
1095 
1096 	blknr = fat_clus_to_blknr(sbi, cluster);
1097 	bhs[0] = sb_getblk(sb, blknr);
1098 	if (!bhs[0]) {
1099 		err = -ENOMEM;
1100 		goto error_free;
1101 	}
1102 
1103 	fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
1104 
1105 	de = (struct msdos_dir_entry *)bhs[0]->b_data;
1106 	/* filling the new directory slots ("." and ".." entries) */
1107 	memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME);
1108 	memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME);
1109 	de->attr = de[1].attr = ATTR_DIR;
1110 	de[0].lcase = de[1].lcase = 0;
1111 	de[0].time = de[1].time = time;
1112 	de[0].date = de[1].date = date;
1113 	if (sbi->options.isvfat) {
1114 		/* extra timestamps */
1115 		de[0].ctime = de[1].ctime = time;
1116 		de[0].ctime_cs = de[1].ctime_cs = time_cs;
1117 		de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date;
1118 	} else {
1119 		de[0].ctime = de[1].ctime = 0;
1120 		de[0].ctime_cs = de[1].ctime_cs = 0;
1121 		de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0;
1122 	}
1123 	de[0].start = cpu_to_le16(cluster);
1124 	de[0].starthi = cpu_to_le16(cluster >> 16);
1125 	de[1].start = cpu_to_le16(MSDOS_I(dir)->i_logstart);
1126 	de[1].starthi = cpu_to_le16(MSDOS_I(dir)->i_logstart >> 16);
1127 	de[0].size = de[1].size = 0;
1128 	memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));
1129 	set_buffer_uptodate(bhs[0]);
1130 	mark_buffer_dirty_inode(bhs[0], dir);
1131 
1132 	err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE);
1133 	if (err)
1134 		goto error_free;
1135 
1136 	return cluster;
1137 
1138 error_free:
1139 	fat_free_clusters(dir, cluster);
1140 error:
1141 	return err;
1142 }
1143 
1144 EXPORT_SYMBOL_GPL(fat_alloc_new_dir);
1145 
1146 static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,
1147 			       int *nr_cluster, struct msdos_dir_entry **de,
1148 			       struct buffer_head **bh, loff_t *i_pos)
1149 {
1150 	struct super_block *sb = dir->i_sb;
1151 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
1152 	struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1153 	sector_t blknr, start_blknr, last_blknr;
1154 	unsigned long size, copy;
1155 	int err, i, n, offset, cluster[2];
1156 
1157 	/*
1158 	 * The minimum cluster size is 512bytes, and maximum entry
1159 	 * size is 32*slots (672bytes).  So, iff the cluster size is
1160 	 * 512bytes, we may need two clusters.
1161 	 */
1162 	size = nr_slots * sizeof(struct msdos_dir_entry);
1163 	*nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits;
1164 	BUG_ON(*nr_cluster > 2);
1165 
1166 	err = fat_alloc_clusters(dir, cluster, *nr_cluster);
1167 	if (err)
1168 		goto error;
1169 
1170 	/*
1171 	 * First stage: Fill the directory entry.  NOTE: This cluster
1172 	 * is not referenced from any inode yet, so updates order is
1173 	 * not important.
1174 	 */
1175 	i = n = copy = 0;
1176 	do {
1177 		start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]);
1178 		last_blknr = start_blknr + sbi->sec_per_clus;
1179 		while (blknr < last_blknr) {
1180 			bhs[n] = sb_getblk(sb, blknr);
1181 			if (!bhs[n]) {
1182 				err = -ENOMEM;
1183 				goto error_nomem;
1184 			}
1185 
1186 			/* fill the directory entry */
1187 			copy = min(size, sb->s_blocksize);
1188 			memcpy(bhs[n]->b_data, slots, copy);
1189 			slots += copy;
1190 			size -= copy;
1191 			set_buffer_uptodate(bhs[n]);
1192 			mark_buffer_dirty_inode(bhs[n], dir);
1193 			if (!size)
1194 				break;
1195 			n++;
1196 			blknr++;
1197 		}
1198 	} while (++i < *nr_cluster);
1199 
1200 	memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy);
1201 	offset = copy - sizeof(struct msdos_dir_entry);
1202 	get_bh(bhs[n]);
1203 	*bh = bhs[n];
1204 	*de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
1205 	*i_pos = fat_make_i_pos(sb, *bh, *de);
1206 
1207 	/* Second stage: clear the rest of cluster, and write outs */
1208 	err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE);
1209 	if (err)
1210 		goto error_free;
1211 
1212 	return cluster[0];
1213 
1214 error_free:
1215 	brelse(*bh);
1216 	*bh = NULL;
1217 	n = 0;
1218 error_nomem:
1219 	for (i = 0; i < n; i++)
1220 		bforget(bhs[i]);
1221 	fat_free_clusters(dir, cluster[0]);
1222 error:
1223 	return err;
1224 }
1225 
1226 int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
1227 		    struct fat_slot_info *sinfo)
1228 {
1229 	struct super_block *sb = dir->i_sb;
1230 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
1231 	struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */
1232 	struct msdos_dir_entry *de;
1233 	int err, free_slots, i, nr_bhs;
1234 	loff_t pos, i_pos;
1235 
1236 	sinfo->nr_slots = nr_slots;
1237 
1238 	/* First stage: search free direcotry entries */
1239 	free_slots = nr_bhs = 0;
1240 	bh = prev = NULL;
1241 	pos = 0;
1242 	err = -ENOSPC;
1243 	while (fat_get_entry(dir, &pos, &bh, &de) > -1) {
1244 		/* check the maximum size of directory */
1245 		if (pos >= FAT_MAX_DIR_SIZE)
1246 			goto error;
1247 
1248 		if (IS_FREE(de->name)) {
1249 			if (prev != bh) {
1250 				get_bh(bh);
1251 				bhs[nr_bhs] = prev = bh;
1252 				nr_bhs++;
1253 			}
1254 			free_slots++;
1255 			if (free_slots == nr_slots)
1256 				goto found;
1257 		} else {
1258 			for (i = 0; i < nr_bhs; i++)
1259 				brelse(bhs[i]);
1260 			prev = NULL;
1261 			free_slots = nr_bhs = 0;
1262 		}
1263 	}
1264 	if (dir->i_ino == MSDOS_ROOT_INO) {
1265 		if (sbi->fat_bits != 32)
1266 			goto error;
1267 	} else if (MSDOS_I(dir)->i_start == 0) {
1268 		printk(KERN_ERR "FAT: Corrupted directory (i_pos %lld)\n",
1269 		       MSDOS_I(dir)->i_pos);
1270 		err = -EIO;
1271 		goto error;
1272 	}
1273 
1274 found:
1275 	err = 0;
1276 	pos -= free_slots * sizeof(*de);
1277 	nr_slots -= free_slots;
1278 	if (free_slots) {
1279 		/*
1280 		 * Second stage: filling the free entries with new entries.
1281 		 * NOTE: If this slots has shortname, first, we write
1282 		 * the long name slots, then write the short name.
1283 		 */
1284 		int size = free_slots * sizeof(*de);
1285 		int offset = pos & (sb->s_blocksize - 1);
1286 		int long_bhs = nr_bhs - (nr_slots == 0);
1287 
1288 		/* Fill the long name slots. */
1289 		for (i = 0; i < long_bhs; i++) {
1290 			int copy = min_t(int, sb->s_blocksize - offset, size);
1291 			memcpy(bhs[i]->b_data + offset, slots, copy);
1292 			mark_buffer_dirty_inode(bhs[i], dir);
1293 			offset = 0;
1294 			slots += copy;
1295 			size -= copy;
1296 		}
1297 		if (long_bhs && IS_DIRSYNC(dir))
1298 			err = fat_sync_bhs(bhs, long_bhs);
1299 		if (!err && i < nr_bhs) {
1300 			/* Fill the short name slot. */
1301 			int copy = min_t(int, sb->s_blocksize - offset, size);
1302 			memcpy(bhs[i]->b_data + offset, slots, copy);
1303 			mark_buffer_dirty_inode(bhs[i], dir);
1304 			if (IS_DIRSYNC(dir))
1305 				err = sync_dirty_buffer(bhs[i]);
1306 		}
1307 		for (i = 0; i < nr_bhs; i++)
1308 			brelse(bhs[i]);
1309 		if (err)
1310 			goto error_remove;
1311 	}
1312 
1313 	if (nr_slots) {
1314 		int cluster, nr_cluster;
1315 
1316 		/*
1317 		 * Third stage: allocate the cluster for new entries.
1318 		 * And initialize the cluster with new entries, then
1319 		 * add the cluster to dir.
1320 		 */
1321 		cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster,
1322 					      &de, &bh, &i_pos);
1323 		if (cluster < 0) {
1324 			err = cluster;
1325 			goto error_remove;
1326 		}
1327 		err = fat_chain_add(dir, cluster, nr_cluster);
1328 		if (err) {
1329 			fat_free_clusters(dir, cluster);
1330 			goto error_remove;
1331 		}
1332 		if (dir->i_size & (sbi->cluster_size - 1)) {
1333 			fat_fs_error(sb, "Odd directory size");
1334 			dir->i_size = (dir->i_size + sbi->cluster_size - 1)
1335 				& ~((loff_t)sbi->cluster_size - 1);
1336 		}
1337 		dir->i_size += nr_cluster << sbi->cluster_bits;
1338 		MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits;
1339 	}
1340 	sinfo->slot_off = pos;
1341 	sinfo->de = de;
1342 	sinfo->bh = bh;
1343 	sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
1344 
1345 	return 0;
1346 
1347 error:
1348 	brelse(bh);
1349 	for (i = 0; i < nr_bhs; i++)
1350 		brelse(bhs[i]);
1351 	return err;
1352 
1353 error_remove:
1354 	brelse(bh);
1355 	if (free_slots)
1356 		__fat_remove_entries(dir, pos, free_slots);
1357 	return err;
1358 }
1359 
1360 EXPORT_SYMBOL_GPL(fat_add_entries);
1361