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

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