1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/fs/fat/dir.c
4 *
5 * directory handling functions for fat-based filesystems
6 *
7 * Written 1992,1993 by Werner Almesberger
8 *
9 * Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
10 *
11 * VFAT extensions by Gordon Chaffee <chaffee@plateau.cs.berkeley.edu>
12 * Merged with msdos fs by Henrik Storner <storner@osiris.ping.dk>
13 * Rewritten for constant inumbers. Plugged buffer overrun in readdir(). AV
14 * Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>
15 */
16
17 #include <linux/slab.h>
18 #include <linux/compat.h>
19 #include <linux/uaccess.h>
20 #include <linux/iversion.h>
21 #include "fat.h"
22
23 /*
24 * Maximum buffer size of short name.
25 * [(MSDOS_NAME + '.') * max one char + nul]
26 * For msdos style, ['.' (hidden) + MSDOS_NAME + '.' + nul]
27 */
28 #define FAT_MAX_SHORT_SIZE ((MSDOS_NAME + 1) * NLS_MAX_CHARSET_SIZE + 1)
29 /*
30 * Maximum buffer size of unicode chars from slots.
31 * [(max longname slots * 13 (size in a slot) + nul) * sizeof(wchar_t)]
32 */
33 #define FAT_MAX_UNI_CHARS ((MSDOS_SLOTS - 1) * 13 + 1)
34 #define FAT_MAX_UNI_SIZE (FAT_MAX_UNI_CHARS * sizeof(wchar_t))
35
fat_tolower(unsigned char c)36 static inline unsigned char fat_tolower(unsigned char c)
37 {
38 return ((c >= 'A') && (c <= 'Z')) ? c+32 : c;
39 }
40
fat_make_i_pos(struct super_block * sb,struct buffer_head * bh,struct msdos_dir_entry * de)41 static inline loff_t fat_make_i_pos(struct super_block *sb,
42 struct buffer_head *bh,
43 struct msdos_dir_entry *de)
44 {
45 return ((loff_t)bh->b_blocknr << MSDOS_SB(sb)->dir_per_block_bits)
46 | (de - (struct msdos_dir_entry *)bh->b_data);
47 }
48
fat_dir_readahead(struct inode * dir,sector_t iblock,sector_t phys)49 static inline void fat_dir_readahead(struct inode *dir, sector_t iblock,
50 sector_t phys)
51 {
52 struct super_block *sb = dir->i_sb;
53 struct msdos_sb_info *sbi = MSDOS_SB(sb);
54 struct buffer_head *bh;
55 int sec;
56
57 /* This is not a first sector of cluster, or sec_per_clus == 1 */
58 if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1)
59 return;
60 /* root dir of FAT12/FAT16 */
61 if (!is_fat32(sbi) && (dir->i_ino == MSDOS_ROOT_INO))
62 return;
63
64 bh = sb_find_get_block(sb, phys);
65 if (bh == NULL || !buffer_uptodate(bh)) {
66 for (sec = 0; sec < sbi->sec_per_clus; sec++)
67 sb_breadahead(sb, phys + sec);
68 }
69 brelse(bh);
70 }
71
72 /* Returns the inode number of the directory entry at offset pos. If bh is
73 non-NULL, it is brelse'd before. Pos is incremented. The buffer header is
74 returned in bh.
75 AV. Most often we do it item-by-item. Makes sense to optimize.
76 AV. OK, there we go: if both bh and de are non-NULL we assume that we just
77 AV. want the next entry (took one explicit de=NULL in vfat/namei.c).
78 AV. It's done in fat_get_entry() (inlined), here the slow case lives.
79 AV. Additionally, when we return -1 (i.e. reached the end of directory)
80 AV. we make bh NULL.
81 */
fat__get_entry(struct inode * dir,loff_t * pos,struct buffer_head ** bh,struct msdos_dir_entry ** de)82 static int fat__get_entry(struct inode *dir, loff_t *pos,
83 struct buffer_head **bh, struct msdos_dir_entry **de)
84 {
85 struct super_block *sb = dir->i_sb;
86 sector_t phys, iblock;
87 unsigned long mapped_blocks;
88 int err, offset;
89
90 next:
91 brelse(*bh);
92 *bh = NULL;
93 iblock = *pos >> sb->s_blocksize_bits;
94 err = fat_bmap(dir, iblock, &phys, &mapped_blocks, 0, false);
95 if (err || !phys)
96 return -1; /* beyond EOF or error */
97
98 fat_dir_readahead(dir, iblock, phys);
99
100 *bh = sb_bread(sb, phys);
101 if (*bh == NULL) {
102 fat_msg_ratelimit(sb, KERN_ERR,
103 "Directory bread(block %llu) failed", (llu)phys);
104 /* skip this block */
105 *pos = (iblock + 1) << sb->s_blocksize_bits;
106 goto next;
107 }
108
109 offset = *pos & (sb->s_blocksize - 1);
110 *pos += sizeof(struct msdos_dir_entry);
111 *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
112
113 return 0;
114 }
115
fat_get_entry(struct inode * dir,loff_t * pos,struct buffer_head ** bh,struct msdos_dir_entry ** de)116 static inline int fat_get_entry(struct inode *dir, loff_t *pos,
117 struct buffer_head **bh,
118 struct msdos_dir_entry **de)
119 {
120 /* Fast stuff first */
121 if (*bh && *de &&
122 (*de - (struct msdos_dir_entry *)(*bh)->b_data) <
123 MSDOS_SB(dir->i_sb)->dir_per_block - 1) {
124 *pos += sizeof(struct msdos_dir_entry);
125 (*de)++;
126 return 0;
127 }
128 return fat__get_entry(dir, pos, bh, de);
129 }
130
131 /*
132 * Convert Unicode 16 to UTF-8, translated Unicode, or ASCII.
133 * If uni_xlate is enabled and we can't get a 1:1 conversion, use a
134 * colon as an escape character since it is normally invalid on the vfat
135 * filesystem. The following four characters are the hexadecimal digits
136 * of Unicode value. This lets us do a full dump and restore of Unicode
137 * filenames. We could get into some trouble with long Unicode names,
138 * but ignore that right now.
139 * Ahem... Stack smashing in ring 0 isn't fun. Fixed.
140 */
uni16_to_x8(struct super_block * sb,unsigned char * ascii,const wchar_t * uni,int len,struct nls_table * nls)141 static int uni16_to_x8(struct super_block *sb, unsigned char *ascii,
142 const wchar_t *uni, int len, struct nls_table *nls)
143 {
144 int uni_xlate = MSDOS_SB(sb)->options.unicode_xlate;
145 const wchar_t *ip;
146 wchar_t ec;
147 unsigned char *op;
148 int charlen;
149
150 ip = uni;
151 op = ascii;
152
153 while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {
154 ec = *ip++;
155 charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE);
156 if (charlen > 0) {
157 op += charlen;
158 len -= charlen;
159 } else {
160 if (uni_xlate == 1) {
161 *op++ = ':';
162 op = hex_byte_pack(op, ec >> 8);
163 op = hex_byte_pack(op, ec);
164 len -= 5;
165 } else {
166 *op++ = '?';
167 len--;
168 }
169 }
170 }
171
172 if (unlikely(*ip)) {
173 fat_msg(sb, KERN_WARNING,
174 "filename was truncated while converting.");
175 }
176
177 *op = 0;
178 return op - ascii;
179 }
180
fat_uni_to_x8(struct super_block * sb,const wchar_t * uni,unsigned char * buf,int size)181 static inline int fat_uni_to_x8(struct super_block *sb, const wchar_t *uni,
182 unsigned char *buf, int size)
183 {
184 struct msdos_sb_info *sbi = MSDOS_SB(sb);
185 if (sbi->options.utf8)
186 return utf16s_to_utf8s(uni, FAT_MAX_UNI_CHARS,
187 UTF16_HOST_ENDIAN, buf, size);
188 else
189 return uni16_to_x8(sb, buf, uni, size, sbi->nls_io);
190 }
191
192 static inline int
fat_short2uni(struct nls_table * t,unsigned char * c,int clen,wchar_t * uni)193 fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
194 {
195 int charlen;
196
197 charlen = t->char2uni(c, clen, uni);
198 if (charlen < 0) {
199 *uni = 0x003f; /* a question mark */
200 charlen = 1;
201 }
202 return charlen;
203 }
204
205 static inline int
fat_short2lower_uni(struct nls_table * t,unsigned char * c,int clen,wchar_t * uni)206 fat_short2lower_uni(struct nls_table *t, unsigned char *c,
207 int clen, wchar_t *uni)
208 {
209 int charlen;
210 wchar_t wc;
211
212 charlen = t->char2uni(c, clen, &wc);
213 if (charlen < 0) {
214 *uni = 0x003f; /* a question mark */
215 charlen = 1;
216 } else if (charlen <= 1) {
217 unsigned char nc = t->charset2lower[*c];
218
219 if (!nc)
220 nc = *c;
221
222 charlen = t->char2uni(&nc, 1, uni);
223 if (charlen < 0) {
224 *uni = 0x003f; /* a question mark */
225 charlen = 1;
226 }
227 } else
228 *uni = wc;
229
230 return charlen;
231 }
232
233 static inline int
fat_shortname2uni(struct nls_table * nls,unsigned char * buf,int buf_size,wchar_t * uni_buf,unsigned short opt,int lower)234 fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size,
235 wchar_t *uni_buf, unsigned short opt, int lower)
236 {
237 int len = 0;
238
239 if (opt & VFAT_SFN_DISPLAY_LOWER)
240 len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
241 else if (opt & VFAT_SFN_DISPLAY_WIN95)
242 len = fat_short2uni(nls, buf, buf_size, uni_buf);
243 else if (opt & VFAT_SFN_DISPLAY_WINNT) {
244 if (lower)
245 len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
246 else
247 len = fat_short2uni(nls, buf, buf_size, uni_buf);
248 } else
249 len = fat_short2uni(nls, buf, buf_size, uni_buf);
250
251 return len;
252 }
253
fat_name_match(struct msdos_sb_info * sbi,const unsigned char * a,int a_len,const unsigned char * b,int b_len)254 static inline int fat_name_match(struct msdos_sb_info *sbi,
255 const unsigned char *a, int a_len,
256 const unsigned char *b, int b_len)
257 {
258 if (a_len != b_len)
259 return 0;
260
261 if (sbi->options.name_check != 's')
262 return !nls_strnicmp(sbi->nls_io, a, b, a_len);
263 else
264 return !memcmp(a, b, a_len);
265 }
266
267 enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, };
268
269 /**
270 * fat_parse_long - Parse extended directory entry.
271 *
272 * This function returns zero on success, negative value on error, or one of
273 * the following:
274 *
275 * %PARSE_INVALID - Directory entry is invalid.
276 * %PARSE_NOT_LONGNAME - Directory entry does not contain longname.
277 * %PARSE_EOF - Directory has no more entries.
278 */
fat_parse_long(struct inode * dir,loff_t * pos,struct buffer_head ** bh,struct msdos_dir_entry ** de,wchar_t ** unicode,unsigned char * nr_slots)279 static int fat_parse_long(struct inode *dir, loff_t *pos,
280 struct buffer_head **bh, struct msdos_dir_entry **de,
281 wchar_t **unicode, unsigned char *nr_slots)
282 {
283 struct msdos_dir_slot *ds;
284 unsigned char id, slot, slots, alias_checksum;
285
286 if (!*unicode) {
287 *unicode = __getname();
288 if (!*unicode) {
289 brelse(*bh);
290 return -ENOMEM;
291 }
292 }
293 parse_long:
294 ds = (struct msdos_dir_slot *)*de;
295 id = ds->id;
296 if (!(id & 0x40))
297 return PARSE_INVALID;
298 slots = id & ~0x40;
299 if (slots > 20 || !slots) /* ceil(256 * 2 / 26) */
300 return PARSE_INVALID;
301 *nr_slots = slots;
302 alias_checksum = ds->alias_checksum;
303
304 slot = slots;
305 while (1) {
306 int offset;
307
308 slot--;
309 offset = slot * 13;
310 fat16_towchar(*unicode + offset, ds->name0_4, 5);
311 fat16_towchar(*unicode + offset + 5, ds->name5_10, 6);
312 fat16_towchar(*unicode + offset + 11, ds->name11_12, 2);
313
314 if (ds->id & 0x40)
315 (*unicode)[offset + 13] = 0;
316 if (fat_get_entry(dir, pos, bh, de) < 0)
317 return PARSE_EOF;
318 if (slot == 0)
319 break;
320 ds = (struct msdos_dir_slot *)*de;
321 if (ds->attr != ATTR_EXT)
322 return PARSE_NOT_LONGNAME;
323 if ((ds->id & ~0x40) != slot)
324 goto parse_long;
325 if (ds->alias_checksum != alias_checksum)
326 goto parse_long;
327 }
328 if ((*de)->name[0] == DELETED_FLAG)
329 return PARSE_INVALID;
330 if ((*de)->attr == ATTR_EXT)
331 goto parse_long;
332 if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME))
333 return PARSE_INVALID;
334 if (fat_checksum((*de)->name) != alias_checksum)
335 *nr_slots = 0;
336
337 return 0;
338 }
339
340 /**
341 * fat_parse_short - Parse MS-DOS (short) directory entry.
342 * @sb: superblock
343 * @de: directory entry to parse
344 * @name: FAT_MAX_SHORT_SIZE array in which to place extracted name
345 * @dot_hidden: Nonzero == prepend '.' to names with ATTR_HIDDEN
346 *
347 * Returns the number of characters extracted into 'name'.
348 */
fat_parse_short(struct super_block * sb,const struct msdos_dir_entry * de,unsigned char * name,int dot_hidden)349 static int fat_parse_short(struct super_block *sb,
350 const struct msdos_dir_entry *de,
351 unsigned char *name, int dot_hidden)
352 {
353 const struct msdos_sb_info *sbi = MSDOS_SB(sb);
354 int isvfat = sbi->options.isvfat;
355 int nocase = sbi->options.nocase;
356 unsigned short opt_shortname = sbi->options.shortname;
357 struct nls_table *nls_disk = sbi->nls_disk;
358 wchar_t uni_name[14];
359 unsigned char c, work[MSDOS_NAME];
360 unsigned char *ptname = name;
361 int chi, chl, i, j, k;
362 int dotoffset = 0;
363 int name_len = 0, uni_len = 0;
364
365 if (!isvfat && dot_hidden && (de->attr & ATTR_HIDDEN)) {
366 *ptname++ = '.';
367 dotoffset = 1;
368 }
369
370 memcpy(work, de->name, sizeof(work));
371 /* For an explanation of the special treatment of 0x05 in
372 * filenames, see msdos_format_name in namei_msdos.c
373 */
374 if (work[0] == 0x05)
375 work[0] = 0xE5;
376
377 /* Filename */
378 for (i = 0, j = 0; i < 8;) {
379 c = work[i];
380 if (!c)
381 break;
382 chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
383 &uni_name[j++], opt_shortname,
384 de->lcase & CASE_LOWER_BASE);
385 if (chl <= 1) {
386 if (!isvfat)
387 ptname[i] = nocase ? c : fat_tolower(c);
388 i++;
389 if (c != ' ') {
390 name_len = i;
391 uni_len = j;
392 }
393 } else {
394 uni_len = j;
395 if (isvfat)
396 i += min(chl, 8-i);
397 else {
398 for (chi = 0; chi < chl && i < 8; chi++, i++)
399 ptname[i] = work[i];
400 }
401 if (chl)
402 name_len = i;
403 }
404 }
405
406 i = name_len;
407 j = uni_len;
408 fat_short2uni(nls_disk, ".", 1, &uni_name[j++]);
409 if (!isvfat)
410 ptname[i] = '.';
411 i++;
412
413 /* Extension */
414 for (k = 8; k < MSDOS_NAME;) {
415 c = work[k];
416 if (!c)
417 break;
418 chl = fat_shortname2uni(nls_disk, &work[k], MSDOS_NAME - k,
419 &uni_name[j++], opt_shortname,
420 de->lcase & CASE_LOWER_EXT);
421 if (chl <= 1) {
422 k++;
423 if (!isvfat)
424 ptname[i] = nocase ? c : fat_tolower(c);
425 i++;
426 if (c != ' ') {
427 name_len = i;
428 uni_len = j;
429 }
430 } else {
431 uni_len = j;
432 if (isvfat) {
433 int offset = min(chl, MSDOS_NAME-k);
434 k += offset;
435 i += offset;
436 } else {
437 for (chi = 0; chi < chl && k < MSDOS_NAME;
438 chi++, i++, k++) {
439 ptname[i] = work[k];
440 }
441 }
442 if (chl)
443 name_len = i;
444 }
445 }
446
447 if (name_len > 0) {
448 name_len += dotoffset;
449
450 if (sbi->options.isvfat) {
451 uni_name[uni_len] = 0x0000;
452 name_len = fat_uni_to_x8(sb, uni_name, name,
453 FAT_MAX_SHORT_SIZE);
454 }
455 }
456
457 return name_len;
458 }
459
460 /*
461 * Return values: negative -> error/not found, 0 -> found.
462 */
fat_search_long(struct inode * inode,const unsigned char * name,int name_len,struct fat_slot_info * sinfo)463 int fat_search_long(struct inode *inode, const unsigned char *name,
464 int name_len, struct fat_slot_info *sinfo)
465 {
466 struct super_block *sb = inode->i_sb;
467 struct msdos_sb_info *sbi = MSDOS_SB(sb);
468 struct buffer_head *bh = NULL;
469 struct msdos_dir_entry *de;
470 unsigned char nr_slots;
471 wchar_t *unicode = NULL;
472 unsigned char bufname[FAT_MAX_SHORT_SIZE];
473 loff_t cpos = 0;
474 int err, len;
475
476 err = -ENOENT;
477 while (1) {
478 if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
479 goto end_of_dir;
480 parse_record:
481 nr_slots = 0;
482 if (de->name[0] == DELETED_FLAG)
483 continue;
484 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
485 continue;
486 if (de->attr != ATTR_EXT && IS_FREE(de->name))
487 continue;
488 if (de->attr == ATTR_EXT) {
489 int status = fat_parse_long(inode, &cpos, &bh, &de,
490 &unicode, &nr_slots);
491 if (status < 0) {
492 err = status;
493 goto end_of_dir;
494 } else if (status == PARSE_INVALID)
495 continue;
496 else if (status == PARSE_NOT_LONGNAME)
497 goto parse_record;
498 else if (status == PARSE_EOF)
499 goto end_of_dir;
500 }
501
502 /* Never prepend '.' to hidden files here.
503 * That is done only for msdos mounts (and only when
504 * 'dotsOK=yes'); if we are executing here, it is in the
505 * context of a vfat mount.
506 */
507 len = fat_parse_short(sb, de, bufname, 0);
508 if (len == 0)
509 continue;
510
511 /* Compare shortname */
512 if (fat_name_match(sbi, name, name_len, bufname, len))
513 goto found;
514
515 if (nr_slots) {
516 void *longname = unicode + FAT_MAX_UNI_CHARS;
517 int size = PATH_MAX - FAT_MAX_UNI_SIZE;
518
519 /* Compare longname */
520 len = fat_uni_to_x8(sb, unicode, longname, size);
521 if (fat_name_match(sbi, name, name_len, longname, len))
522 goto found;
523 }
524 }
525
526 found:
527 nr_slots++; /* include the de */
528 sinfo->slot_off = cpos - nr_slots * sizeof(*de);
529 sinfo->nr_slots = nr_slots;
530 sinfo->de = de;
531 sinfo->bh = bh;
532 sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
533 err = 0;
534 end_of_dir:
535 if (unicode)
536 __putname(unicode);
537
538 return err;
539 }
540 EXPORT_SYMBOL_GPL(fat_search_long);
541
542 struct fat_ioctl_filldir_callback {
543 struct dir_context ctx;
544 void __user *dirent;
545 int result;
546 /* for dir ioctl */
547 const char *longname;
548 int long_len;
549 const char *shortname;
550 int short_len;
551 };
552
__fat_readdir(struct inode * inode,struct file * file,struct dir_context * ctx,int short_only,struct fat_ioctl_filldir_callback * both)553 static int __fat_readdir(struct inode *inode, struct file *file,
554 struct dir_context *ctx, int short_only,
555 struct fat_ioctl_filldir_callback *both)
556 {
557 struct super_block *sb = inode->i_sb;
558 struct msdos_sb_info *sbi = MSDOS_SB(sb);
559 struct buffer_head *bh;
560 struct msdos_dir_entry *de;
561 unsigned char nr_slots;
562 wchar_t *unicode = NULL;
563 unsigned char bufname[FAT_MAX_SHORT_SIZE];
564 int isvfat = sbi->options.isvfat;
565 const char *fill_name = NULL;
566 int fake_offset = 0;
567 loff_t cpos;
568 int short_len = 0, fill_len = 0;
569 int ret = 0;
570
571 mutex_lock(&sbi->s_lock);
572
573 cpos = ctx->pos;
574 /* Fake . and .. for the root directory. */
575 if (inode->i_ino == MSDOS_ROOT_INO) {
576 if (!dir_emit_dots(file, ctx))
577 goto out;
578 if (ctx->pos == 2) {
579 fake_offset = 1;
580 cpos = 0;
581 }
582 }
583 if (cpos & (sizeof(struct msdos_dir_entry) - 1)) {
584 ret = -ENOENT;
585 goto out;
586 }
587
588 bh = NULL;
589 get_new:
590 if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
591 goto end_of_dir;
592 parse_record:
593 nr_slots = 0;
594 /*
595 * Check for long filename entry, but if short_only, we don't
596 * need to parse long filename.
597 */
598 if (isvfat && !short_only) {
599 if (de->name[0] == DELETED_FLAG)
600 goto record_end;
601 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
602 goto record_end;
603 if (de->attr != ATTR_EXT && IS_FREE(de->name))
604 goto record_end;
605 } else {
606 if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))
607 goto record_end;
608 }
609
610 if (isvfat && de->attr == ATTR_EXT) {
611 int status = fat_parse_long(inode, &cpos, &bh, &de,
612 &unicode, &nr_slots);
613 if (status < 0) {
614 bh = NULL;
615 ret = status;
616 goto end_of_dir;
617 } else if (status == PARSE_INVALID)
618 goto record_end;
619 else if (status == PARSE_NOT_LONGNAME)
620 goto parse_record;
621 else if (status == PARSE_EOF)
622 goto end_of_dir;
623
624 if (nr_slots) {
625 void *longname = unicode + FAT_MAX_UNI_CHARS;
626 int size = PATH_MAX - FAT_MAX_UNI_SIZE;
627 int len = fat_uni_to_x8(sb, unicode, longname, size);
628
629 fill_name = longname;
630 fill_len = len;
631 /* !both && !short_only, so we don't need shortname. */
632 if (!both)
633 goto start_filldir;
634
635 short_len = fat_parse_short(sb, de, bufname,
636 sbi->options.dotsOK);
637 if (short_len == 0)
638 goto record_end;
639 /* hack for fat_ioctl_filldir() */
640 both->longname = fill_name;
641 both->long_len = fill_len;
642 both->shortname = bufname;
643 both->short_len = short_len;
644 fill_name = NULL;
645 fill_len = 0;
646 goto start_filldir;
647 }
648 }
649
650 short_len = fat_parse_short(sb, de, bufname, sbi->options.dotsOK);
651 if (short_len == 0)
652 goto record_end;
653
654 fill_name = bufname;
655 fill_len = short_len;
656
657 start_filldir:
658 ctx->pos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
659 if (fake_offset && ctx->pos < 2)
660 ctx->pos = 2;
661
662 if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME)) {
663 if (!dir_emit_dot(file, ctx))
664 goto fill_failed;
665 } else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
666 if (!dir_emit_dotdot(file, ctx))
667 goto fill_failed;
668 } else {
669 unsigned long inum;
670 loff_t i_pos = fat_make_i_pos(sb, bh, de);
671 struct inode *tmp = fat_iget(sb, i_pos);
672 if (tmp) {
673 inum = tmp->i_ino;
674 iput(tmp);
675 } else
676 inum = iunique(sb, MSDOS_ROOT_INO);
677 if (!dir_emit(ctx, fill_name, fill_len, inum,
678 (de->attr & ATTR_DIR) ? DT_DIR : DT_REG))
679 goto fill_failed;
680 }
681
682 record_end:
683 fake_offset = 0;
684 ctx->pos = cpos;
685 goto get_new;
686
687 end_of_dir:
688 if (fake_offset && cpos < 2)
689 ctx->pos = 2;
690 else
691 ctx->pos = cpos;
692 fill_failed:
693 brelse(bh);
694 if (unicode)
695 __putname(unicode);
696 out:
697 mutex_unlock(&sbi->s_lock);
698
699 return ret;
700 }
701
fat_readdir(struct file * file,struct dir_context * ctx)702 static int fat_readdir(struct file *file, struct dir_context *ctx)
703 {
704 return __fat_readdir(file_inode(file), file, ctx, 0, NULL);
705 }
706
707 #define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type) \
708 static int func(struct dir_context *ctx, const char *name, int name_len, \
709 loff_t offset, u64 ino, unsigned int d_type) \
710 { \
711 struct fat_ioctl_filldir_callback *buf = \
712 container_of(ctx, struct fat_ioctl_filldir_callback, ctx); \
713 struct dirent_type __user *d1 = buf->dirent; \
714 struct dirent_type __user *d2 = d1 + 1; \
715 \
716 if (buf->result) \
717 return -EINVAL; \
718 buf->result++; \
719 \
720 if (name != NULL) { \
721 /* dirent has only short name */ \
722 if (name_len >= sizeof(d1->d_name)) \
723 name_len = sizeof(d1->d_name) - 1; \
724 \
725 if (put_user(0, d2->d_name) || \
726 put_user(0, &d2->d_reclen) || \
727 copy_to_user(d1->d_name, name, name_len) || \
728 put_user(0, d1->d_name + name_len) || \
729 put_user(name_len, &d1->d_reclen)) \
730 goto efault; \
731 } else { \
732 /* dirent has short and long name */ \
733 const char *longname = buf->longname; \
734 int long_len = buf->long_len; \
735 const char *shortname = buf->shortname; \
736 int short_len = buf->short_len; \
737 \
738 if (long_len >= sizeof(d1->d_name)) \
739 long_len = sizeof(d1->d_name) - 1; \
740 if (short_len >= sizeof(d1->d_name)) \
741 short_len = sizeof(d1->d_name) - 1; \
742 \
743 if (copy_to_user(d2->d_name, longname, long_len) || \
744 put_user(0, d2->d_name + long_len) || \
745 put_user(long_len, &d2->d_reclen) || \
746 put_user(ino, &d2->d_ino) || \
747 put_user(offset, &d2->d_off) || \
748 copy_to_user(d1->d_name, shortname, short_len) || \
749 put_user(0, d1->d_name + short_len) || \
750 put_user(short_len, &d1->d_reclen)) \
751 goto efault; \
752 } \
753 return 0; \
754 efault: \
755 buf->result = -EFAULT; \
756 return -EFAULT; \
757 }
758
FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir,__fat_dirent)759 FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)
760
761 static int fat_ioctl_readdir(struct inode *inode, struct file *file,
762 void __user *dirent, filldir_t filldir,
763 int short_only, int both)
764 {
765 struct fat_ioctl_filldir_callback buf = {
766 .ctx.actor = filldir,
767 .dirent = dirent
768 };
769 int ret;
770
771 buf.dirent = dirent;
772 buf.result = 0;
773 inode_lock_shared(inode);
774 buf.ctx.pos = file->f_pos;
775 ret = -ENOENT;
776 if (!IS_DEADDIR(inode)) {
777 ret = __fat_readdir(inode, file, &buf.ctx,
778 short_only, both ? &buf : NULL);
779 file->f_pos = buf.ctx.pos;
780 }
781 inode_unlock_shared(inode);
782 if (ret >= 0)
783 ret = buf.result;
784 return ret;
785 }
786
fat_dir_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)787 static long fat_dir_ioctl(struct file *filp, unsigned int cmd,
788 unsigned long arg)
789 {
790 struct inode *inode = file_inode(filp);
791 struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg;
792 int short_only, both;
793
794 switch (cmd) {
795 case VFAT_IOCTL_READDIR_SHORT:
796 short_only = 1;
797 both = 0;
798 break;
799 case VFAT_IOCTL_READDIR_BOTH:
800 short_only = 0;
801 both = 1;
802 break;
803 default:
804 return fat_generic_ioctl(filp, cmd, arg);
805 }
806
807 /*
808 * Yes, we don't need this put_user() absolutely. However old
809 * code didn't return the right value. So, app use this value,
810 * in order to check whether it is EOF.
811 */
812 if (put_user(0, &d1->d_reclen))
813 return -EFAULT;
814
815 return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir,
816 short_only, both);
817 }
818
819 #ifdef CONFIG_COMPAT
820 #define VFAT_IOCTL_READDIR_BOTH32 _IOR('r', 1, struct compat_dirent[2])
821 #define VFAT_IOCTL_READDIR_SHORT32 _IOR('r', 2, struct compat_dirent[2])
822
FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir,compat_dirent)823 FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent)
824
825 static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd,
826 unsigned long arg)
827 {
828 struct inode *inode = file_inode(filp);
829 struct compat_dirent __user *d1 = compat_ptr(arg);
830 int short_only, both;
831
832 switch (cmd) {
833 case VFAT_IOCTL_READDIR_SHORT32:
834 short_only = 1;
835 both = 0;
836 break;
837 case VFAT_IOCTL_READDIR_BOTH32:
838 short_only = 0;
839 both = 1;
840 break;
841 default:
842 return fat_generic_ioctl(filp, cmd, (unsigned long)arg);
843 }
844
845 /*
846 * Yes, we don't need this put_user() absolutely. However old
847 * code didn't return the right value. So, app use this value,
848 * in order to check whether it is EOF.
849 */
850 if (put_user(0, &d1->d_reclen))
851 return -EFAULT;
852
853 return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir,
854 short_only, both);
855 }
856 #endif /* CONFIG_COMPAT */
857
858 const struct file_operations fat_dir_operations = {
859 .llseek = generic_file_llseek,
860 .read = generic_read_dir,
861 .iterate_shared = fat_readdir,
862 .unlocked_ioctl = fat_dir_ioctl,
863 #ifdef CONFIG_COMPAT
864 .compat_ioctl = fat_compat_dir_ioctl,
865 #endif
866 .fsync = fat_file_fsync,
867 };
868
fat_get_short_entry(struct inode * dir,loff_t * pos,struct buffer_head ** bh,struct msdos_dir_entry ** de)869 static int fat_get_short_entry(struct inode *dir, loff_t *pos,
870 struct buffer_head **bh,
871 struct msdos_dir_entry **de)
872 {
873 while (fat_get_entry(dir, pos, bh, de) >= 0) {
874 /* free entry or long name entry or volume label */
875 if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))
876 return 0;
877 }
878 return -ENOENT;
879 }
880
881 /*
882 * The ".." entry can not provide the "struct fat_slot_info" information
883 * for inode, nor a usable i_pos. So, this function provides some information
884 * only.
885 *
886 * Since this function walks through the on-disk inodes within a directory,
887 * callers are responsible for taking any locks necessary to prevent the
888 * directory from changing.
889 */
fat_get_dotdot_entry(struct inode * dir,struct buffer_head ** bh,struct msdos_dir_entry ** de)890 int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
891 struct msdos_dir_entry **de)
892 {
893 loff_t offset = 0;
894
895 *de = NULL;
896 while (fat_get_short_entry(dir, &offset, bh, de) >= 0) {
897 if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME))
898 return 0;
899 }
900 return -ENOENT;
901 }
902 EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);
903
904 /* See if directory is empty */
fat_dir_empty(struct inode * dir)905 int fat_dir_empty(struct inode *dir)
906 {
907 struct buffer_head *bh;
908 struct msdos_dir_entry *de;
909 loff_t cpos;
910 int result = 0;
911
912 bh = NULL;
913 cpos = 0;
914 while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
915 if (strncmp(de->name, MSDOS_DOT , MSDOS_NAME) &&
916 strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
917 result = -ENOTEMPTY;
918 break;
919 }
920 }
921 brelse(bh);
922 return result;
923 }
924 EXPORT_SYMBOL_GPL(fat_dir_empty);
925
926 /*
927 * fat_subdirs counts the number of sub-directories of dir. It can be run
928 * on directories being created.
929 */
fat_subdirs(struct inode * dir)930 int fat_subdirs(struct inode *dir)
931 {
932 struct buffer_head *bh;
933 struct msdos_dir_entry *de;
934 loff_t cpos;
935 int count = 0;
936
937 bh = NULL;
938 cpos = 0;
939 while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
940 if (de->attr & ATTR_DIR)
941 count++;
942 }
943 brelse(bh);
944 return count;
945 }
946
947 /*
948 * Scans a directory for a given file (name points to its formatted name).
949 * Returns an error code or zero.
950 */
fat_scan(struct inode * dir,const unsigned char * name,struct fat_slot_info * sinfo)951 int fat_scan(struct inode *dir, const unsigned char *name,
952 struct fat_slot_info *sinfo)
953 {
954 struct super_block *sb = dir->i_sb;
955
956 sinfo->slot_off = 0;
957 sinfo->bh = NULL;
958 while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
959 &sinfo->de) >= 0) {
960 if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) {
961 sinfo->slot_off -= sizeof(*sinfo->de);
962 sinfo->nr_slots = 1;
963 sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
964 return 0;
965 }
966 }
967 return -ENOENT;
968 }
969 EXPORT_SYMBOL_GPL(fat_scan);
970
971 /*
972 * Scans a directory for a given logstart.
973 * Returns an error code or zero.
974 */
fat_scan_logstart(struct inode * dir,int i_logstart,struct fat_slot_info * sinfo)975 int fat_scan_logstart(struct inode *dir, int i_logstart,
976 struct fat_slot_info *sinfo)
977 {
978 struct super_block *sb = dir->i_sb;
979
980 sinfo->slot_off = 0;
981 sinfo->bh = NULL;
982 while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
983 &sinfo->de) >= 0) {
984 if (fat_get_start(MSDOS_SB(sb), sinfo->de) == i_logstart) {
985 sinfo->slot_off -= sizeof(*sinfo->de);
986 sinfo->nr_slots = 1;
987 sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
988 return 0;
989 }
990 }
991 return -ENOENT;
992 }
993
__fat_remove_entries(struct inode * dir,loff_t pos,int nr_slots)994 static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)
995 {
996 struct super_block *sb = dir->i_sb;
997 struct buffer_head *bh;
998 struct msdos_dir_entry *de, *endp;
999 int err = 0, orig_slots;
1000
1001 while (nr_slots) {
1002 bh = NULL;
1003 if (fat_get_entry(dir, &pos, &bh, &de) < 0) {
1004 err = -EIO;
1005 break;
1006 }
1007
1008 orig_slots = nr_slots;
1009 endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize);
1010 while (nr_slots && de < endp) {
1011 de->name[0] = DELETED_FLAG;
1012 de++;
1013 nr_slots--;
1014 }
1015 mark_buffer_dirty_inode(bh, dir);
1016 if (IS_DIRSYNC(dir))
1017 err = sync_dirty_buffer(bh);
1018 brelse(bh);
1019 if (err)
1020 break;
1021
1022 /* pos is *next* de's position, so this does `- sizeof(de)' */
1023 pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de);
1024 }
1025
1026 return err;
1027 }
1028
fat_remove_entries(struct inode * dir,struct fat_slot_info * sinfo)1029 int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)
1030 {
1031 struct super_block *sb = dir->i_sb;
1032 struct msdos_dir_entry *de;
1033 struct buffer_head *bh;
1034 int err = 0, nr_slots;
1035
1036 /*
1037 * First stage: Remove the shortname. By this, the directory
1038 * entry is removed.
1039 */
1040 nr_slots = sinfo->nr_slots;
1041 de = sinfo->de;
1042 sinfo->de = NULL;
1043 bh = sinfo->bh;
1044 sinfo->bh = NULL;
1045 while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) {
1046 de->name[0] = DELETED_FLAG;
1047 de--;
1048 nr_slots--;
1049 }
1050 mark_buffer_dirty_inode(bh, dir);
1051 if (IS_DIRSYNC(dir))
1052 err = sync_dirty_buffer(bh);
1053 brelse(bh);
1054 if (err)
1055 return err;
1056 inode_inc_iversion(dir);
1057
1058 if (nr_slots) {
1059 /*
1060 * Second stage: remove the remaining longname slots.
1061 * (This directory entry is already removed, and so return
1062 * the success)
1063 */
1064 err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots);
1065 if (err) {
1066 fat_msg(sb, KERN_WARNING,
1067 "Couldn't remove the long name slots");
1068 }
1069 }
1070
1071 fat_truncate_time(dir, NULL, S_ATIME|S_MTIME);
1072 if (IS_DIRSYNC(dir))
1073 (void)fat_sync_inode(dir);
1074 else
1075 mark_inode_dirty(dir);
1076
1077 return 0;
1078 }
1079 EXPORT_SYMBOL_GPL(fat_remove_entries);
1080
fat_zeroed_cluster(struct inode * dir,sector_t blknr,int nr_used,struct buffer_head ** bhs,int nr_bhs)1081 static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,
1082 struct buffer_head **bhs, int nr_bhs)
1083 {
1084 struct super_block *sb = dir->i_sb;
1085 sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus;
1086 int err, i, n;
1087
1088 /* Zeroing the unused blocks on this cluster */
1089 blknr += nr_used;
1090 n = nr_used;
1091 while (blknr < last_blknr) {
1092 bhs[n] = sb_getblk(sb, blknr);
1093 if (!bhs[n]) {
1094 err = -ENOMEM;
1095 goto error;
1096 }
1097 /* Avoid race with userspace read via bdev */
1098 lock_buffer(bhs[n]);
1099 memset(bhs[n]->b_data, 0, sb->s_blocksize);
1100 set_buffer_uptodate(bhs[n]);
1101 unlock_buffer(bhs[n]);
1102 mark_buffer_dirty_inode(bhs[n], dir);
1103
1104 n++;
1105 blknr++;
1106 if (n == nr_bhs) {
1107 if (IS_DIRSYNC(dir)) {
1108 err = fat_sync_bhs(bhs, n);
1109 if (err)
1110 goto error;
1111 }
1112 for (i = 0; i < n; i++)
1113 brelse(bhs[i]);
1114 n = 0;
1115 }
1116 }
1117 if (IS_DIRSYNC(dir)) {
1118 err = fat_sync_bhs(bhs, n);
1119 if (err)
1120 goto error;
1121 }
1122 for (i = 0; i < n; i++)
1123 brelse(bhs[i]);
1124
1125 return 0;
1126
1127 error:
1128 for (i = 0; i < n; i++)
1129 bforget(bhs[i]);
1130 return err;
1131 }
1132
fat_alloc_new_dir(struct inode * dir,struct timespec64 * ts)1133 int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts)
1134 {
1135 struct super_block *sb = dir->i_sb;
1136 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1137 struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1138 struct msdos_dir_entry *de;
1139 sector_t blknr;
1140 __le16 date, time;
1141 u8 time_cs;
1142 int err, cluster;
1143
1144 err = fat_alloc_clusters(dir, &cluster, 1);
1145 if (err)
1146 goto error;
1147
1148 blknr = fat_clus_to_blknr(sbi, cluster);
1149 bhs[0] = sb_getblk(sb, blknr);
1150 if (!bhs[0]) {
1151 err = -ENOMEM;
1152 goto error_free;
1153 }
1154
1155 fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
1156
1157 de = (struct msdos_dir_entry *)bhs[0]->b_data;
1158 /* Avoid race with userspace read via bdev */
1159 lock_buffer(bhs[0]);
1160 /* filling the new directory slots ("." and ".." entries) */
1161 memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME);
1162 memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME);
1163 de->attr = de[1].attr = ATTR_DIR;
1164 de[0].lcase = de[1].lcase = 0;
1165 de[0].time = de[1].time = time;
1166 de[0].date = de[1].date = date;
1167 if (sbi->options.isvfat) {
1168 /* extra timestamps */
1169 de[0].ctime = de[1].ctime = time;
1170 de[0].ctime_cs = de[1].ctime_cs = time_cs;
1171 de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date;
1172 } else {
1173 de[0].ctime = de[1].ctime = 0;
1174 de[0].ctime_cs = de[1].ctime_cs = 0;
1175 de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0;
1176 }
1177 fat_set_start(&de[0], cluster);
1178 fat_set_start(&de[1], MSDOS_I(dir)->i_logstart);
1179 de[0].size = de[1].size = 0;
1180 memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));
1181 set_buffer_uptodate(bhs[0]);
1182 unlock_buffer(bhs[0]);
1183 mark_buffer_dirty_inode(bhs[0], dir);
1184
1185 err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE);
1186 if (err)
1187 goto error_free;
1188
1189 return cluster;
1190
1191 error_free:
1192 fat_free_clusters(dir, cluster);
1193 error:
1194 return err;
1195 }
1196 EXPORT_SYMBOL_GPL(fat_alloc_new_dir);
1197
fat_add_new_entries(struct inode * dir,void * slots,int nr_slots,int * nr_cluster,struct msdos_dir_entry ** de,struct buffer_head ** bh,loff_t * i_pos)1198 static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,
1199 int *nr_cluster, struct msdos_dir_entry **de,
1200 struct buffer_head **bh, loff_t *i_pos)
1201 {
1202 struct super_block *sb = dir->i_sb;
1203 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1204 struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1205 sector_t blknr, start_blknr, last_blknr;
1206 unsigned long size, copy;
1207 int err, i, n, offset, cluster[2];
1208
1209 /*
1210 * The minimum cluster size is 512bytes, and maximum entry
1211 * size is 32*slots (672bytes). So, iff the cluster size is
1212 * 512bytes, we may need two clusters.
1213 */
1214 size = nr_slots * sizeof(struct msdos_dir_entry);
1215 *nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits;
1216 BUG_ON(*nr_cluster > 2);
1217
1218 err = fat_alloc_clusters(dir, cluster, *nr_cluster);
1219 if (err)
1220 goto error;
1221
1222 /*
1223 * First stage: Fill the directory entry. NOTE: This cluster
1224 * is not referenced from any inode yet, so updates order is
1225 * not important.
1226 */
1227 i = n = copy = 0;
1228 do {
1229 start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]);
1230 last_blknr = start_blknr + sbi->sec_per_clus;
1231 while (blknr < last_blknr) {
1232 bhs[n] = sb_getblk(sb, blknr);
1233 if (!bhs[n]) {
1234 err = -ENOMEM;
1235 goto error_nomem;
1236 }
1237
1238 /* fill the directory entry */
1239 copy = min(size, sb->s_blocksize);
1240 /* Avoid race with userspace read via bdev */
1241 lock_buffer(bhs[n]);
1242 memcpy(bhs[n]->b_data, slots, copy);
1243 set_buffer_uptodate(bhs[n]);
1244 unlock_buffer(bhs[n]);
1245 mark_buffer_dirty_inode(bhs[n], dir);
1246 slots += copy;
1247 size -= copy;
1248 if (!size)
1249 break;
1250 n++;
1251 blknr++;
1252 }
1253 } while (++i < *nr_cluster);
1254
1255 memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy);
1256 offset = copy - sizeof(struct msdos_dir_entry);
1257 get_bh(bhs[n]);
1258 *bh = bhs[n];
1259 *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
1260 *i_pos = fat_make_i_pos(sb, *bh, *de);
1261
1262 /* Second stage: clear the rest of cluster, and write outs */
1263 err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE);
1264 if (err)
1265 goto error_free;
1266
1267 return cluster[0];
1268
1269 error_free:
1270 brelse(*bh);
1271 *bh = NULL;
1272 n = 0;
1273 error_nomem:
1274 for (i = 0; i < n; i++)
1275 bforget(bhs[i]);
1276 fat_free_clusters(dir, cluster[0]);
1277 error:
1278 return err;
1279 }
1280
fat_add_entries(struct inode * dir,void * slots,int nr_slots,struct fat_slot_info * sinfo)1281 int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
1282 struct fat_slot_info *sinfo)
1283 {
1284 struct super_block *sb = dir->i_sb;
1285 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1286 struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */
1287 struct msdos_dir_entry *de;
1288 int err, free_slots, i, nr_bhs;
1289 loff_t pos, i_pos;
1290
1291 sinfo->nr_slots = nr_slots;
1292
1293 /* First stage: search free directory entries */
1294 free_slots = nr_bhs = 0;
1295 bh = prev = NULL;
1296 pos = 0;
1297 err = -ENOSPC;
1298 while (fat_get_entry(dir, &pos, &bh, &de) > -1) {
1299 /* check the maximum size of directory */
1300 if (pos >= FAT_MAX_DIR_SIZE)
1301 goto error;
1302
1303 if (IS_FREE(de->name)) {
1304 if (prev != bh) {
1305 get_bh(bh);
1306 bhs[nr_bhs] = prev = bh;
1307 nr_bhs++;
1308 }
1309 free_slots++;
1310 if (free_slots == nr_slots)
1311 goto found;
1312 } else {
1313 for (i = 0; i < nr_bhs; i++)
1314 brelse(bhs[i]);
1315 prev = NULL;
1316 free_slots = nr_bhs = 0;
1317 }
1318 }
1319 if (dir->i_ino == MSDOS_ROOT_INO) {
1320 if (!is_fat32(sbi))
1321 goto error;
1322 } else if (MSDOS_I(dir)->i_start == 0) {
1323 fat_msg(sb, KERN_ERR, "Corrupted directory (i_pos %lld)",
1324 MSDOS_I(dir)->i_pos);
1325 err = -EIO;
1326 goto error;
1327 }
1328
1329 found:
1330 err = 0;
1331 pos -= free_slots * sizeof(*de);
1332 nr_slots -= free_slots;
1333 if (free_slots) {
1334 /*
1335 * Second stage: filling the free entries with new entries.
1336 * NOTE: If this slots has shortname, first, we write
1337 * the long name slots, then write the short name.
1338 */
1339 int size = free_slots * sizeof(*de);
1340 int offset = pos & (sb->s_blocksize - 1);
1341 int long_bhs = nr_bhs - (nr_slots == 0);
1342
1343 /* Fill the long name slots. */
1344 for (i = 0; i < long_bhs; i++) {
1345 int copy = min_t(int, sb->s_blocksize - offset, size);
1346 memcpy(bhs[i]->b_data + offset, slots, copy);
1347 mark_buffer_dirty_inode(bhs[i], dir);
1348 offset = 0;
1349 slots += copy;
1350 size -= copy;
1351 }
1352 if (long_bhs && IS_DIRSYNC(dir))
1353 err = fat_sync_bhs(bhs, long_bhs);
1354 if (!err && i < nr_bhs) {
1355 /* Fill the short name slot. */
1356 int copy = min_t(int, sb->s_blocksize - offset, size);
1357 memcpy(bhs[i]->b_data + offset, slots, copy);
1358 mark_buffer_dirty_inode(bhs[i], dir);
1359 if (IS_DIRSYNC(dir))
1360 err = sync_dirty_buffer(bhs[i]);
1361 }
1362 for (i = 0; i < nr_bhs; i++)
1363 brelse(bhs[i]);
1364 if (err)
1365 goto error_remove;
1366 }
1367
1368 if (nr_slots) {
1369 int cluster, nr_cluster;
1370
1371 /*
1372 * Third stage: allocate the cluster for new entries.
1373 * And initialize the cluster with new entries, then
1374 * add the cluster to dir.
1375 */
1376 cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster,
1377 &de, &bh, &i_pos);
1378 if (cluster < 0) {
1379 err = cluster;
1380 goto error_remove;
1381 }
1382 err = fat_chain_add(dir, cluster, nr_cluster);
1383 if (err) {
1384 fat_free_clusters(dir, cluster);
1385 goto error_remove;
1386 }
1387 if (dir->i_size & (sbi->cluster_size - 1)) {
1388 fat_fs_error(sb, "Odd directory size");
1389 dir->i_size = (dir->i_size + sbi->cluster_size - 1)
1390 & ~((loff_t)sbi->cluster_size - 1);
1391 }
1392 dir->i_size += nr_cluster << sbi->cluster_bits;
1393 MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits;
1394 }
1395 sinfo->slot_off = pos;
1396 sinfo->de = de;
1397 sinfo->bh = bh;
1398 sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
1399
1400 return 0;
1401
1402 error:
1403 brelse(bh);
1404 for (i = 0; i < nr_bhs; i++)
1405 brelse(bhs[i]);
1406 return err;
1407
1408 error_remove:
1409 brelse(bh);
1410 if (free_slots)
1411 __fat_remove_entries(dir, pos, free_slots);
1412 return err;
1413 }
1414 EXPORT_SYMBOL_GPL(fat_add_entries);
1415