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

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