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TOMOYO Linux Cross Reference
Linux/fs/fat/dir.c

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  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/slab.h>
 17 #include <linux/compat.h>
 18 #include <linux/uaccess.h>
 19 #include "fat.h"
 20 
 21 /*
 22  * Maximum buffer size of short name.
 23  * [(MSDOS_NAME + '.') * max one char + nul]
 24  * For msdos style, ['.' (hidden) + MSDOS_NAME + '.' + nul]
 25  */
 26 #define FAT_MAX_SHORT_SIZE      ((MSDOS_NAME + 1) * NLS_MAX_CHARSET_SIZE + 1)
 27 /*
 28  * Maximum buffer size of unicode chars from slots.
 29  * [(max longname slots * 13 (size in a slot) + nul) * sizeof(wchar_t)]
 30  */
 31 #define FAT_MAX_UNI_CHARS       ((MSDOS_SLOTS - 1) * 13 + 1)
 32 #define FAT_MAX_UNI_SIZE        (FAT_MAX_UNI_CHARS * sizeof(wchar_t))
 33 
 34 static inline unsigned char fat_tolower(unsigned char c)
 35 {
 36         return ((c >= 'A') && (c <= 'Z')) ? c+32 : c;
 37 }
 38 
 39 static inline loff_t fat_make_i_pos(struct super_block *sb,
 40                                     struct buffer_head *bh,
 41                                     struct msdos_dir_entry *de)
 42 {
 43         return ((loff_t)bh->b_blocknr << MSDOS_SB(sb)->dir_per_block_bits)
 44                 | (de - (struct msdos_dir_entry *)bh->b_data);
 45 }
 46 
 47 static inline void fat_dir_readahead(struct inode *dir, sector_t iblock,
 48                                      sector_t phys)
 49 {
 50         struct super_block *sb = dir->i_sb;
 51         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 52         struct buffer_head *bh;
 53         int sec;
 54 
 55         /* This is not a first sector of cluster, or sec_per_clus == 1 */
 56         if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1)
 57                 return;
 58         /* root dir of FAT12/FAT16 */
 59         if ((sbi->fat_bits != 32) && (dir->i_ino == MSDOS_ROOT_INO))
 60                 return;
 61 
 62         bh = sb_find_get_block(sb, phys);
 63         if (bh == NULL || !buffer_uptodate(bh)) {
 64                 for (sec = 0; sec < sbi->sec_per_clus; sec++)
 65                         sb_breadahead(sb, phys + sec);
 66         }
 67         brelse(bh);
 68 }
 69 
 70 /* Returns the inode number of the directory entry at offset pos. If bh is
 71    non-NULL, it is brelse'd before. Pos is incremented. The buffer header is
 72    returned in bh.
 73    AV. Most often we do it item-by-item. Makes sense to optimize.
 74    AV. OK, there we go: if both bh and de are non-NULL we assume that we just
 75    AV. want the next entry (took one explicit de=NULL in vfat/namei.c).
 76    AV. It's done in fat_get_entry() (inlined), here the slow case lives.
 77    AV. Additionally, when we return -1 (i.e. reached the end of directory)
 78    AV. we make bh NULL.
 79  */
 80 static int fat__get_entry(struct inode *dir, loff_t *pos,
 81                           struct buffer_head **bh, struct msdos_dir_entry **de)
 82 {
 83         struct super_block *sb = dir->i_sb;
 84         sector_t phys, iblock;
 85         unsigned long mapped_blocks;
 86         int err, offset;
 87 
 88 next:
 89         if (*bh)
 90                 brelse(*bh);
 91 
 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 
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  */
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 
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
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
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
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 
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  */
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  */
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         /* see namei.c, msdos_format_name */
372         if (work[0] == 0x05)
373                 work[0] = 0xE5;
374 
375         /* Filename */
376         for (i = 0, j = 0; i < 8;) {
377                 c = work[i];
378                 if (!c)
379                         break;
380                 chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
381                                         &uni_name[j++], opt_shortname,
382                                         de->lcase & CASE_LOWER_BASE);
383                 if (chl <= 1) {
384                         if (!isvfat)
385                                 ptname[i] = nocase ? c : fat_tolower(c);
386                         i++;
387                         if (c != ' ') {
388                                 name_len = i;
389                                 uni_len  = j;
390                         }
391                 } else {
392                         uni_len = j;
393                         if (isvfat)
394                                 i += min(chl, 8-i);
395                         else {
396                                 for (chi = 0; chi < chl && i < 8; chi++, i++)
397                                         ptname[i] = work[i];
398                         }
399                         if (chl)
400                                 name_len = i;
401                 }
402         }
403 
404         i = name_len;
405         j = uni_len;
406         fat_short2uni(nls_disk, ".", 1, &uni_name[j++]);
407         if (!isvfat)
408                 ptname[i] = '.';
409         i++;
410 
411         /* Extension */
412         for (k = 8; k < MSDOS_NAME;) {
413                 c = work[k];
414                 if (!c)
415                         break;
416                 chl = fat_shortname2uni(nls_disk, &work[k], MSDOS_NAME - k,
417                                         &uni_name[j++], opt_shortname,
418                                         de->lcase & CASE_LOWER_EXT);
419                 if (chl <= 1) {
420                         k++;
421                         if (!isvfat)
422                                 ptname[i] = nocase ? c : fat_tolower(c);
423                         i++;
424                         if (c != ' ') {
425                                 name_len = i;
426                                 uni_len  = j;
427                         }
428                 } else {
429                         uni_len = j;
430                         if (isvfat) {
431                                 int offset = min(chl, MSDOS_NAME-k);
432                                 k += offset;
433                                 i += offset;
434                         } else {
435                                 for (chi = 0; chi < chl && k < MSDOS_NAME;
436                                      chi++, i++, k++) {
437                                                 ptname[i] = work[k];
438                                 }
439                         }
440                         if (chl)
441                                 name_len = i;
442                 }
443         }
444 
445         if (name_len > 0) {
446                 name_len += dotoffset;
447 
448                 if (sbi->options.isvfat) {
449                         uni_name[uni_len] = 0x0000;
450                         name_len = fat_uni_to_x8(sb, uni_name, name,
451                                                  FAT_MAX_SHORT_SIZE);
452                 }
453         }
454 
455         return name_len;
456 }
457 
458 /*
459  * Return values: negative -> error/not found, 0 -> found.
460  */
461 int fat_search_long(struct inode *inode, const unsigned char *name,
462                     int name_len, struct fat_slot_info *sinfo)
463 {
464         struct super_block *sb = inode->i_sb;
465         struct msdos_sb_info *sbi = MSDOS_SB(sb);
466         struct buffer_head *bh = NULL;
467         struct msdos_dir_entry *de;
468         unsigned char nr_slots;
469         wchar_t *unicode = NULL;
470         unsigned char bufname[FAT_MAX_SHORT_SIZE];
471         loff_t cpos = 0;
472         int err, len;
473 
474         err = -ENOENT;
475         while (1) {
476                 if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
477                         goto end_of_dir;
478 parse_record:
479                 nr_slots = 0;
480                 if (de->name[0] == DELETED_FLAG)
481                         continue;
482                 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
483                         continue;
484                 if (de->attr != ATTR_EXT && IS_FREE(de->name))
485                         continue;
486                 if (de->attr == ATTR_EXT) {
487                         int status = fat_parse_long(inode, &cpos, &bh, &de,
488                                                     &unicode, &nr_slots);
489                         if (status < 0) {
490                                 err = status;
491                                 goto end_of_dir;
492                         } else if (status == PARSE_INVALID)
493                                 continue;
494                         else if (status == PARSE_NOT_LONGNAME)
495                                 goto parse_record;
496                         else if (status == PARSE_EOF)
497                                 goto end_of_dir;
498                 }
499 
500                 /* Never prepend '.' to hidden files here.
501                  * That is done only for msdos mounts (and only when
502                  * 'dotsOK=yes'); if we are executing here, it is in the
503                  * context of a vfat mount.
504                  */
505                 len = fat_parse_short(sb, de, bufname, 0);
506                 if (len == 0)
507                         continue;
508 
509                 /* Compare shortname */
510                 if (fat_name_match(sbi, name, name_len, bufname, len))
511                         goto found;
512 
513                 if (nr_slots) {
514                         void *longname = unicode + FAT_MAX_UNI_CHARS;
515                         int size = PATH_MAX - FAT_MAX_UNI_SIZE;
516 
517                         /* Compare longname */
518                         len = fat_uni_to_x8(sb, unicode, longname, size);
519                         if (fat_name_match(sbi, name, name_len, longname, len))
520                                 goto found;
521                 }
522         }
523 
524 found:
525         nr_slots++;     /* include the de */
526         sinfo->slot_off = cpos - nr_slots * sizeof(*de);
527         sinfo->nr_slots = nr_slots;
528         sinfo->de = de;
529         sinfo->bh = bh;
530         sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
531         err = 0;
532 end_of_dir:
533         if (unicode)
534                 __putname(unicode);
535 
536         return err;
537 }
538 EXPORT_SYMBOL_GPL(fat_search_long);
539 
540 struct fat_ioctl_filldir_callback {
541         struct dir_context ctx;
542         void __user *dirent;
543         int result;
544         /* for dir ioctl */
545         const char *longname;
546         int long_len;
547         const char *shortname;
548         int short_len;
549 };
550 
551 static int __fat_readdir(struct inode *inode, struct file *file,
552                          struct dir_context *ctx, int short_only,
553                          struct fat_ioctl_filldir_callback *both)
554 {
555         struct super_block *sb = inode->i_sb;
556         struct msdos_sb_info *sbi = MSDOS_SB(sb);
557         struct buffer_head *bh;
558         struct msdos_dir_entry *de;
559         unsigned char nr_slots;
560         wchar_t *unicode = NULL;
561         unsigned char bufname[FAT_MAX_SHORT_SIZE];
562         int isvfat = sbi->options.isvfat;
563         const char *fill_name = NULL;
564         int fake_offset = 0;
565         loff_t cpos;
566         int short_len = 0, fill_len = 0;
567         int ret = 0;
568 
569         mutex_lock(&sbi->s_lock);
570 
571         cpos = ctx->pos;
572         /* Fake . and .. for the root directory. */
573         if (inode->i_ino == MSDOS_ROOT_INO) {
574                 if (!dir_emit_dots(file, ctx))
575                         goto out;
576                 if (ctx->pos == 2) {
577                         fake_offset = 1;
578                         cpos = 0;
579                 }
580         }
581         if (cpos & (sizeof(struct msdos_dir_entry) - 1)) {
582                 ret = -ENOENT;
583                 goto out;
584         }
585 
586         bh = NULL;
587 get_new:
588         if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
589                 goto end_of_dir;
590 parse_record:
591         nr_slots = 0;
592         /*
593          * Check for long filename entry, but if short_only, we don't
594          * need to parse long filename.
595          */
596         if (isvfat && !short_only) {
597                 if (de->name[0] == DELETED_FLAG)
598                         goto record_end;
599                 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
600                         goto record_end;
601                 if (de->attr != ATTR_EXT && IS_FREE(de->name))
602                         goto record_end;
603         } else {
604                 if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))
605                         goto record_end;
606         }
607 
608         if (isvfat && de->attr == ATTR_EXT) {
609                 int status = fat_parse_long(inode, &cpos, &bh, &de,
610                                             &unicode, &nr_slots);
611                 if (status < 0) {
612                         bh = NULL;
613                         ret = status;
614                         goto end_of_dir;
615                 } else if (status == PARSE_INVALID)
616                         goto record_end;
617                 else if (status == PARSE_NOT_LONGNAME)
618                         goto parse_record;
619                 else if (status == PARSE_EOF)
620                         goto end_of_dir;
621 
622                 if (nr_slots) {
623                         void *longname = unicode + FAT_MAX_UNI_CHARS;
624                         int size = PATH_MAX - FAT_MAX_UNI_SIZE;
625                         int len = fat_uni_to_x8(sb, unicode, longname, size);
626 
627                         fill_name = longname;
628                         fill_len = len;
629                         /* !both && !short_only, so we don't need shortname. */
630                         if (!both)
631                                 goto start_filldir;
632 
633                         short_len = fat_parse_short(sb, de, bufname,
634                                                     sbi->options.dotsOK);
635                         if (short_len == 0)
636                                 goto record_end;
637                         /* hack for fat_ioctl_filldir() */
638                         both->longname = fill_name;
639                         both->long_len = fill_len;
640                         both->shortname = bufname;
641                         both->short_len = short_len;
642                         fill_name = NULL;
643                         fill_len = 0;
644                         goto start_filldir;
645                 }
646         }
647 
648         short_len = fat_parse_short(sb, de, bufname, sbi->options.dotsOK);
649         if (short_len == 0)
650                 goto record_end;
651 
652         fill_name = bufname;
653         fill_len = short_len;
654 
655 start_filldir:
656         ctx->pos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
657         if (fake_offset && ctx->pos < 2)
658                 ctx->pos = 2;
659 
660         if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME)) {
661                 if (!dir_emit_dot(file, ctx))
662                         goto fill_failed;
663         } else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
664                 if (!dir_emit_dotdot(file, ctx))
665                         goto fill_failed;
666         } else {
667                 unsigned long inum;
668                 loff_t i_pos = fat_make_i_pos(sb, bh, de);
669                 struct inode *tmp = fat_iget(sb, i_pos);
670                 if (tmp) {
671                         inum = tmp->i_ino;
672                         iput(tmp);
673                 } else
674                         inum = iunique(sb, MSDOS_ROOT_INO);
675                 if (!dir_emit(ctx, fill_name, fill_len, inum,
676                             (de->attr & ATTR_DIR) ? DT_DIR : DT_REG))
677                         goto fill_failed;
678         }
679 
680 record_end:
681         fake_offset = 0;
682         ctx->pos = cpos;
683         goto get_new;
684 
685 end_of_dir:
686         if (fake_offset && cpos < 2)
687                 ctx->pos = 2;
688         else
689                 ctx->pos = cpos;
690 fill_failed:
691         brelse(bh);
692         if (unicode)
693                 __putname(unicode);
694 out:
695         mutex_unlock(&sbi->s_lock);
696 
697         return ret;
698 }
699 
700 static int fat_readdir(struct file *file, struct dir_context *ctx)
701 {
702         return __fat_readdir(file_inode(file), file, ctx, 0, NULL);
703 }
704 
705 #define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type)                          \
706 static int func(struct dir_context *ctx, const char *name, int name_len,   \
707                              loff_t offset, u64 ino, unsigned int d_type)  \
708 {                                                                          \
709         struct fat_ioctl_filldir_callback *buf =                           \
710                 container_of(ctx, struct fat_ioctl_filldir_callback, ctx); \
711         struct dirent_type __user *d1 = buf->dirent;                       \
712         struct dirent_type __user *d2 = d1 + 1;                            \
713                                                                            \
714         if (buf->result)                                                   \
715                 return -EINVAL;                                            \
716         buf->result++;                                                     \
717                                                                            \
718         if (name != NULL) {                                                \
719                 /* dirent has only short name */                           \
720                 if (name_len >= sizeof(d1->d_name))                        \
721                         name_len = sizeof(d1->d_name) - 1;                 \
722                                                                            \
723                 if (put_user(0, d2->d_name)                     ||         \
724                     put_user(0, &d2->d_reclen)                  ||         \
725                     copy_to_user(d1->d_name, name, name_len)    ||         \
726                     put_user(0, d1->d_name + name_len)          ||         \
727                     put_user(name_len, &d1->d_reclen))                     \
728                         goto efault;                                       \
729         } else {                                                           \
730                 /* dirent has short and long name */                       \
731                 const char *longname = buf->longname;                      \
732                 int long_len = buf->long_len;                              \
733                 const char *shortname = buf->shortname;                    \
734                 int short_len = buf->short_len;                            \
735                                                                            \
736                 if (long_len >= sizeof(d1->d_name))                        \
737                         long_len = sizeof(d1->d_name) - 1;                 \
738                 if (short_len >= sizeof(d1->d_name))                       \
739                         short_len = sizeof(d1->d_name) - 1;                \
740                                                                            \
741                 if (copy_to_user(d2->d_name, longname, long_len)        || \
742                     put_user(0, d2->d_name + long_len)                  || \
743                     put_user(long_len, &d2->d_reclen)                   || \
744                     put_user(ino, &d2->d_ino)                           || \
745                     put_user(offset, &d2->d_off)                        || \
746                     copy_to_user(d1->d_name, shortname, short_len)      || \
747                     put_user(0, d1->d_name + short_len)                 || \
748                     put_user(short_len, &d1->d_reclen))                    \
749                         goto efault;                                       \
750         }                                                                  \
751         return 0;                                                          \
752 efault:                                                                    \
753         buf->result = -EFAULT;                                             \
754         return -EFAULT;                                                    \
755 }
756 
757 FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)
758 
759 static int fat_ioctl_readdir(struct inode *inode, struct file *file,
760                              void __user *dirent, filldir_t filldir,
761                              int short_only, int both)
762 {
763         struct fat_ioctl_filldir_callback buf = {
764                 .ctx.actor = filldir,
765                 .dirent = dirent
766         };
767         int ret;
768 
769         buf.dirent = dirent;
770         buf.result = 0;
771         inode_lock_shared(inode);
772         buf.ctx.pos = file->f_pos;
773         ret = -ENOENT;
774         if (!IS_DEADDIR(inode)) {
775                 ret = __fat_readdir(inode, file, &buf.ctx,
776                                     short_only, both ? &buf : NULL);
777                 file->f_pos = buf.ctx.pos;
778         }
779         inode_unlock_shared(inode);
780         if (ret >= 0)
781                 ret = buf.result;
782         return ret;
783 }
784 
785 static long fat_dir_ioctl(struct file *filp, unsigned int cmd,
786                           unsigned long arg)
787 {
788         struct inode *inode = file_inode(filp);
789         struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg;
790         int short_only, both;
791 
792         switch (cmd) {
793         case VFAT_IOCTL_READDIR_SHORT:
794                 short_only = 1;
795                 both = 0;
796                 break;
797         case VFAT_IOCTL_READDIR_BOTH:
798                 short_only = 0;
799                 both = 1;
800                 break;
801         default:
802                 return fat_generic_ioctl(filp, cmd, arg);
803         }
804 
805         if (!access_ok(VERIFY_WRITE, d1, sizeof(struct __fat_dirent[2])))
806                 return -EFAULT;
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 
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         if (!access_ok(VERIFY_WRITE, d1, sizeof(struct compat_dirent[2])))
846                 return -EFAULT;
847         /*
848          * Yes, we don't need this put_user() absolutely. However old
849          * code didn't return the right value. So, app use this value,
850          * in order to check whether it is EOF.
851          */
852         if (put_user(0, &d1->d_reclen))
853                 return -EFAULT;
854 
855         return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir,
856                                  short_only, both);
857 }
858 #endif /* CONFIG_COMPAT */
859 
860 const struct file_operations fat_dir_operations = {
861         .llseek         = generic_file_llseek,
862         .read           = generic_read_dir,
863         .iterate_shared = fat_readdir,
864         .unlocked_ioctl = fat_dir_ioctl,
865 #ifdef CONFIG_COMPAT
866         .compat_ioctl   = fat_compat_dir_ioctl,
867 #endif
868         .fsync          = fat_file_fsync,
869 };
870 
871 static int fat_get_short_entry(struct inode *dir, loff_t *pos,
872                                struct buffer_head **bh,
873                                struct msdos_dir_entry **de)
874 {
875         while (fat_get_entry(dir, pos, bh, de) >= 0) {
876                 /* free entry or long name entry or volume label */
877                 if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))
878                         return 0;
879         }
880         return -ENOENT;
881 }
882 
883 /*
884  * The ".." entry can not provide the "struct fat_slot_info" information
885  * for inode, nor a usable i_pos. So, this function provides some information
886  * only.
887  *
888  * Since this function walks through the on-disk inodes within a directory,
889  * callers are responsible for taking any locks necessary to prevent the
890  * directory from changing.
891  */
892 int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
893                          struct msdos_dir_entry **de)
894 {
895         loff_t offset = 0;
896 
897         *de = NULL;
898         while (fat_get_short_entry(dir, &offset, bh, de) >= 0) {
899                 if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME))
900                         return 0;
901         }
902         return -ENOENT;
903 }
904 EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);
905 
906 /* See if directory is empty */
907 int fat_dir_empty(struct inode *dir)
908 {
909         struct buffer_head *bh;
910         struct msdos_dir_entry *de;
911         loff_t cpos;
912         int result = 0;
913 
914         bh = NULL;
915         cpos = 0;
916         while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
917                 if (strncmp(de->name, MSDOS_DOT   , MSDOS_NAME) &&
918                     strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
919                         result = -ENOTEMPTY;
920                         break;
921                 }
922         }
923         brelse(bh);
924         return result;
925 }
926 EXPORT_SYMBOL_GPL(fat_dir_empty);
927 
928 /*
929  * fat_subdirs counts the number of sub-directories of dir. It can be run
930  * on directories being created.
931  */
932 int fat_subdirs(struct inode *dir)
933 {
934         struct buffer_head *bh;
935         struct msdos_dir_entry *de;
936         loff_t cpos;
937         int count = 0;
938 
939         bh = NULL;
940         cpos = 0;
941         while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
942                 if (de->attr & ATTR_DIR)
943                         count++;
944         }
945         brelse(bh);
946         return count;
947 }
948 
949 /*
950  * Scans a directory for a given file (name points to its formatted name).
951  * Returns an error code or zero.
952  */
953 int fat_scan(struct inode *dir, const unsigned char *name,
954              struct fat_slot_info *sinfo)
955 {
956         struct super_block *sb = dir->i_sb;
957 
958         sinfo->slot_off = 0;
959         sinfo->bh = NULL;
960         while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
961                                    &sinfo->de) >= 0) {
962                 if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) {
963                         sinfo->slot_off -= sizeof(*sinfo->de);
964                         sinfo->nr_slots = 1;
965                         sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
966                         return 0;
967                 }
968         }
969         return -ENOENT;
970 }
971 EXPORT_SYMBOL_GPL(fat_scan);
972 
973 /*
974  * Scans a directory for a given logstart.
975  * Returns an error code or zero.
976  */
977 int fat_scan_logstart(struct inode *dir, int i_logstart,
978                       struct fat_slot_info *sinfo)
979 {
980         struct super_block *sb = dir->i_sb;
981 
982         sinfo->slot_off = 0;
983         sinfo->bh = NULL;
984         while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
985                                    &sinfo->de) >= 0) {
986                 if (fat_get_start(MSDOS_SB(sb), sinfo->de) == i_logstart) {
987                         sinfo->slot_off -= sizeof(*sinfo->de);
988                         sinfo->nr_slots = 1;
989                         sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
990                         return 0;
991                 }
992         }
993         return -ENOENT;
994 }
995 
996 static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)
997 {
998         struct super_block *sb = dir->i_sb;
999         struct buffer_head *bh;
1000         struct msdos_dir_entry *de, *endp;
1001         int err = 0, orig_slots;
1002 
1003         while (nr_slots) {
1004                 bh = NULL;
1005                 if (fat_get_entry(dir, &pos, &bh, &de) < 0) {
1006                         err = -EIO;
1007                         break;
1008                 }
1009 
1010                 orig_slots = nr_slots;
1011                 endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize);
1012                 while (nr_slots && de < endp) {
1013                         de->name[0] = DELETED_FLAG;
1014                         de++;
1015                         nr_slots--;
1016                 }
1017                 mark_buffer_dirty_inode(bh, dir);
1018                 if (IS_DIRSYNC(dir))
1019                         err = sync_dirty_buffer(bh);
1020                 brelse(bh);
1021                 if (err)
1022                         break;
1023 
1024                 /* pos is *next* de's position, so this does `- sizeof(de)' */
1025                 pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de);
1026         }
1027 
1028         return err;
1029 }
1030 
1031 int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)
1032 {
1033         struct super_block *sb = dir->i_sb;
1034         struct msdos_dir_entry *de;
1035         struct buffer_head *bh;
1036         int err = 0, nr_slots;
1037 
1038         /*
1039          * First stage: Remove the shortname. By this, the directory
1040          * entry is removed.
1041          */
1042         nr_slots = sinfo->nr_slots;
1043         de = sinfo->de;
1044         sinfo->de = NULL;
1045         bh = sinfo->bh;
1046         sinfo->bh = NULL;
1047         while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) {
1048                 de->name[0] = DELETED_FLAG;
1049                 de--;
1050                 nr_slots--;
1051         }
1052         mark_buffer_dirty_inode(bh, dir);
1053         if (IS_DIRSYNC(dir))
1054                 err = sync_dirty_buffer(bh);
1055         brelse(bh);
1056         if (err)
1057                 return err;
1058         dir->i_version++;
1059 
1060         if (nr_slots) {
1061                 /*
1062                  * Second stage: remove the remaining longname slots.
1063                  * (This directory entry is already removed, and so return
1064                  * the success)
1065                  */
1066                 err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots);
1067                 if (err) {
1068                         fat_msg(sb, KERN_WARNING,
1069                                "Couldn't remove the long name slots");
1070                 }
1071         }
1072 
1073         dir->i_mtime = dir->i_atime = current_time(dir);
1074         if (IS_DIRSYNC(dir))
1075                 (void)fat_sync_inode(dir);
1076         else
1077                 mark_inode_dirty(dir);
1078 
1079         return 0;
1080 }
1081 EXPORT_SYMBOL_GPL(fat_remove_entries);
1082 
1083 static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,
1084                               struct buffer_head **bhs, int nr_bhs)
1085 {
1086         struct super_block *sb = dir->i_sb;
1087         sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus;
1088         int err, i, n;
1089 
1090         /* Zeroing the unused blocks on this cluster */
1091         blknr += nr_used;
1092         n = nr_used;
1093         while (blknr < last_blknr) {
1094                 bhs[n] = sb_getblk(sb, blknr);
1095                 if (!bhs[n]) {
1096                         err = -ENOMEM;
1097                         goto error;
1098                 }
1099                 memset(bhs[n]->b_data, 0, sb->s_blocksize);
1100                 set_buffer_uptodate(bhs[n]);
1101                 mark_buffer_dirty_inode(bhs[n], dir);
1102 
1103                 n++;
1104                 blknr++;
1105                 if (n == nr_bhs) {
1106                         if (IS_DIRSYNC(dir)) {
1107                                 err = fat_sync_bhs(bhs, n);
1108                                 if (err)
1109                                         goto error;
1110                         }
1111                         for (i = 0; i < n; i++)
1112                                 brelse(bhs[i]);
1113                         n = 0;
1114                 }
1115         }
1116         if (IS_DIRSYNC(dir)) {
1117                 err = fat_sync_bhs(bhs, n);
1118                 if (err)
1119                         goto error;
1120         }
1121         for (i = 0; i < n; i++)
1122                 brelse(bhs[i]);
1123 
1124         return 0;
1125 
1126 error:
1127         for (i = 0; i < n; i++)
1128                 bforget(bhs[i]);
1129         return err;
1130 }
1131 
1132 int fat_alloc_new_dir(struct inode *dir, struct timespec *ts)
1133 {
1134         struct super_block *sb = dir->i_sb;
1135         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1136         struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1137         struct msdos_dir_entry *de;
1138         sector_t blknr;
1139         __le16 date, time;
1140         u8 time_cs;
1141         int err, cluster;
1142 
1143         err = fat_alloc_clusters(dir, &cluster, 1);
1144         if (err)
1145                 goto error;
1146 
1147         blknr = fat_clus_to_blknr(sbi, cluster);
1148         bhs[0] = sb_getblk(sb, blknr);
1149         if (!bhs[0]) {
1150                 err = -ENOMEM;
1151                 goto error_free;
1152         }
1153 
1154         fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
1155 
1156         de = (struct msdos_dir_entry *)bhs[0]->b_data;
1157         /* filling the new directory slots ("." and ".." entries) */
1158         memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME);
1159         memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME);
1160         de->attr = de[1].attr = ATTR_DIR;
1161         de[0].lcase = de[1].lcase = 0;
1162         de[0].time = de[1].time = time;
1163         de[0].date = de[1].date = date;
1164         if (sbi->options.isvfat) {
1165                 /* extra timestamps */
1166                 de[0].ctime = de[1].ctime = time;
1167                 de[0].ctime_cs = de[1].ctime_cs = time_cs;
1168                 de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date;
1169         } else {
1170                 de[0].ctime = de[1].ctime = 0;
1171                 de[0].ctime_cs = de[1].ctime_cs = 0;
1172                 de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0;
1173         }
1174         fat_set_start(&de[0], cluster);
1175         fat_set_start(&de[1], MSDOS_I(dir)->i_logstart);
1176         de[0].size = de[1].size = 0;
1177         memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));
1178         set_buffer_uptodate(bhs[0]);
1179         mark_buffer_dirty_inode(bhs[0], dir);
1180 
1181         err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE);
1182         if (err)
1183                 goto error_free;
1184 
1185         return cluster;
1186 
1187 error_free:
1188         fat_free_clusters(dir, cluster);
1189 error:
1190         return err;
1191 }
1192 EXPORT_SYMBOL_GPL(fat_alloc_new_dir);
1193 
1194 static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,
1195                                int *nr_cluster, struct msdos_dir_entry **de,
1196                                struct buffer_head **bh, loff_t *i_pos)
1197 {
1198         struct super_block *sb = dir->i_sb;
1199         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1200         struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1201         sector_t blknr, start_blknr, last_blknr;
1202         unsigned long size, copy;
1203         int err, i, n, offset, cluster[2];
1204 
1205         /*
1206          * The minimum cluster size is 512bytes, and maximum entry
1207          * size is 32*slots (672bytes).  So, iff the cluster size is
1208          * 512bytes, we may need two clusters.
1209          */
1210         size = nr_slots * sizeof(struct msdos_dir_entry);
1211         *nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits;
1212         BUG_ON(*nr_cluster > 2);
1213 
1214         err = fat_alloc_clusters(dir, cluster, *nr_cluster);
1215         if (err)
1216                 goto error;
1217 
1218         /*
1219          * First stage: Fill the directory entry.  NOTE: This cluster
1220          * is not referenced from any inode yet, so updates order is
1221          * not important.
1222          */
1223         i = n = copy = 0;
1224         do {
1225                 start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]);
1226                 last_blknr = start_blknr + sbi->sec_per_clus;
1227                 while (blknr < last_blknr) {
1228                         bhs[n] = sb_getblk(sb, blknr);
1229                         if (!bhs[n]) {
1230                                 err = -ENOMEM;
1231                                 goto error_nomem;
1232                         }
1233 
1234                         /* fill the directory entry */
1235                         copy = min(size, sb->s_blocksize);
1236                         memcpy(bhs[n]->b_data, slots, copy);
1237                         slots += copy;
1238                         size -= copy;
1239                         set_buffer_uptodate(bhs[n]);
1240                         mark_buffer_dirty_inode(bhs[n], dir);
1241                         if (!size)
1242                                 break;
1243                         n++;
1244                         blknr++;
1245                 }
1246         } while (++i < *nr_cluster);
1247 
1248         memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy);
1249         offset = copy - sizeof(struct msdos_dir_entry);
1250         get_bh(bhs[n]);
1251         *bh = bhs[n];
1252         *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
1253         *i_pos = fat_make_i_pos(sb, *bh, *de);
1254 
1255         /* Second stage: clear the rest of cluster, and write outs */
1256         err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE);
1257         if (err)
1258                 goto error_free;
1259 
1260         return cluster[0];
1261 
1262 error_free:
1263         brelse(*bh);
1264         *bh = NULL;
1265         n = 0;
1266 error_nomem:
1267         for (i = 0; i < n; i++)
1268                 bforget(bhs[i]);
1269         fat_free_clusters(dir, cluster[0]);
1270 error:
1271         return err;
1272 }
1273 
1274 int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
1275                     struct fat_slot_info *sinfo)
1276 {
1277         struct super_block *sb = dir->i_sb;
1278         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1279         struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */
1280         struct msdos_dir_entry *uninitialized_var(de);
1281         int err, free_slots, i, nr_bhs;
1282         loff_t pos, i_pos;
1283 
1284         sinfo->nr_slots = nr_slots;
1285 
1286         /* First stage: search free directory entries */
1287         free_slots = nr_bhs = 0;
1288         bh = prev = NULL;
1289         pos = 0;
1290         err = -ENOSPC;
1291         while (fat_get_entry(dir, &pos, &bh, &de) > -1) {
1292                 /* check the maximum size of directory */
1293                 if (pos >= FAT_MAX_DIR_SIZE)
1294                         goto error;
1295 
1296                 if (IS_FREE(de->name)) {
1297                         if (prev != bh) {
1298                                 get_bh(bh);
1299                                 bhs[nr_bhs] = prev = bh;
1300                                 nr_bhs++;
1301                         }
1302                         free_slots++;
1303                         if (free_slots == nr_slots)
1304                                 goto found;
1305                 } else {
1306                         for (i = 0; i < nr_bhs; i++)
1307                                 brelse(bhs[i]);
1308                         prev = NULL;
1309                         free_slots = nr_bhs = 0;
1310                 }
1311         }
1312         if (dir->i_ino == MSDOS_ROOT_INO) {
1313                 if (sbi->fat_bits != 32)
1314                         goto error;
1315         } else if (MSDOS_I(dir)->i_start == 0) {
1316                 fat_msg(sb, KERN_ERR, "Corrupted directory (i_pos %lld)",
1317                        MSDOS_I(dir)->i_pos);
1318                 err = -EIO;
1319                 goto error;
1320         }
1321 
1322 found:
1323         err = 0;
1324         pos -= free_slots * sizeof(*de);
1325         nr_slots -= free_slots;
1326         if (free_slots) {
1327                 /*
1328                  * Second stage: filling the free entries with new entries.
1329                  * NOTE: If this slots has shortname, first, we write
1330                  * the long name slots, then write the short name.
1331                  */
1332                 int size = free_slots * sizeof(*de);
1333                 int offset = pos & (sb->s_blocksize - 1);
1334                 int long_bhs = nr_bhs - (nr_slots == 0);
1335 
1336                 /* Fill the long name slots. */
1337                 for (i = 0; i < long_bhs; i++) {
1338                         int copy = min_t(int, sb->s_blocksize - offset, size);
1339                         memcpy(bhs[i]->b_data + offset, slots, copy);
1340                         mark_buffer_dirty_inode(bhs[i], dir);
1341                         offset = 0;
1342                         slots += copy;
1343                         size -= copy;
1344                 }
1345                 if (long_bhs && IS_DIRSYNC(dir))
1346                         err = fat_sync_bhs(bhs, long_bhs);
1347                 if (!err && i < nr_bhs) {
1348                         /* Fill the short name slot. */
1349                         int copy = min_t(int, sb->s_blocksize - offset, size);
1350                         memcpy(bhs[i]->b_data + offset, slots, copy);
1351                         mark_buffer_dirty_inode(bhs[i], dir);
1352                         if (IS_DIRSYNC(dir))
1353                                 err = sync_dirty_buffer(bhs[i]);
1354                 }
1355                 for (i = 0; i < nr_bhs; i++)
1356                         brelse(bhs[i]);
1357                 if (err)
1358                         goto error_remove;
1359         }
1360 
1361         if (nr_slots) {
1362                 int cluster, nr_cluster;
1363 
1364                 /*
1365                  * Third stage: allocate the cluster for new entries.
1366                  * And initialize the cluster with new entries, then
1367                  * add the cluster to dir.
1368                  */
1369                 cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster,
1370                                               &de, &bh, &i_pos);
1371                 if (cluster < 0) {
1372                         err = cluster;
1373                         goto error_remove;
1374                 }
1375                 err = fat_chain_add(dir, cluster, nr_cluster);
1376                 if (err) {
1377                         fat_free_clusters(dir, cluster);
1378                         goto error_remove;
1379                 }
1380                 if (dir->i_size & (sbi->cluster_size - 1)) {
1381                         fat_fs_error(sb, "Odd directory size");
1382                         dir->i_size = (dir->i_size + sbi->cluster_size - 1)
1383                                 & ~((loff_t)sbi->cluster_size - 1);
1384                 }
1385                 dir->i_size += nr_cluster << sbi->cluster_bits;
1386                 MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits;
1387         }
1388         sinfo->slot_off = pos;
1389         sinfo->de = de;
1390         sinfo->bh = bh;
1391         sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
1392 
1393         return 0;
1394 
1395 error:
1396         brelse(bh);
1397         for (i = 0; i < nr_bhs; i++)
1398                 brelse(bhs[i]);
1399         return err;
1400 
1401 error_remove:
1402         brelse(bh);
1403         if (free_slots)
1404                 __fat_remove_entries(dir, pos, free_slots);
1405         return err;
1406 }
1407 EXPORT_SYMBOL_GPL(fat_add_entries);
1408 

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