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

Version: ~ [ linux-5.1-rc2 ] ~ [ linux-5.0.3 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.30 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.107 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.164 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.176 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.136 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.63 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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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 <asm/uaccess.h>
 22 #include <linux/kernel.h>
 23 #include "fat.h"
 24 
 25 /*
 26  * Maximum buffer size of short name.
 27  * [(MSDOS_NAME + '.') * max one char + nul]
 28  * For msdos style, ['.' (hidden) + MSDOS_NAME + '.' + nul]
 29  */
 30 #define FAT_MAX_SHORT_SIZE      ((MSDOS_NAME + 1) * NLS_MAX_CHARSET_SIZE + 1)
 31 /*
 32  * Maximum buffer size of unicode chars from slots.
 33  * [(max longname slots * 13 (size in a slot) + nul) * sizeof(wchar_t)]
 34  */
 35 #define FAT_MAX_UNI_CHARS       ((MSDOS_SLOTS - 1) * 13 + 1)
 36 #define FAT_MAX_UNI_SIZE        (FAT_MAX_UNI_CHARS * sizeof(wchar_t))
 37 
 38 static inline loff_t fat_make_i_pos(struct super_block *sb,
 39                                     struct buffer_head *bh,
 40                                     struct msdos_dir_entry *de)
 41 {
 42         return ((loff_t)bh->b_blocknr << MSDOS_SB(sb)->dir_per_block_bits)
 43                 | (de - (struct msdos_dir_entry *)bh->b_data);
 44 }
 45 
 46 static inline void fat_dir_readahead(struct inode *dir, sector_t iblock,
 47                                      sector_t phys)
 48 {
 49         struct super_block *sb = dir->i_sb;
 50         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 51         struct buffer_head *bh;
 52         int sec;
 53 
 54         /* This is not a first sector of cluster, or sec_per_clus == 1 */
 55         if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1)
 56                 return;
 57         /* root dir of FAT12/FAT16 */
 58         if ((sbi->fat_bits != 32) && (dir->i_ino == MSDOS_ROOT_INO))
 59                 return;
 60 
 61         bh = sb_find_get_block(sb, phys);
 62         if (bh == NULL || !buffer_uptodate(bh)) {
 63                 for (sec = 0; sec < sbi->sec_per_clus; sec++)
 64                         sb_breadahead(sb, phys + sec);
 65         }
 66         brelse(bh);
 67 }
 68 
 69 /* Returns the inode number of the directory entry at offset pos. If bh is
 70    non-NULL, it is brelse'd before. Pos is incremented. The buffer header is
 71    returned in bh.
 72    AV. Most often we do it item-by-item. Makes sense to optimize.
 73    AV. OK, there we go: if both bh and de are non-NULL we assume that we just
 74    AV. want the next entry (took one explicit de=NULL in vfat/namei.c).
 75    AV. It's done in fat_get_entry() (inlined), here the slow case lives.
 76    AV. Additionally, when we return -1 (i.e. reached the end of directory)
 77    AV. we make bh NULL.
 78  */
 79 static int fat__get_entry(struct inode *dir, loff_t *pos,
 80                           struct buffer_head **bh, struct msdos_dir_entry **de)
 81 {
 82         struct super_block *sb = dir->i_sb;
 83         sector_t phys, iblock;
 84         unsigned long mapped_blocks;
 85         int err, offset;
 86 
 87 next:
 88         if (*bh)
 89                 brelse(*bh);
 90 
 91         *bh = NULL;
 92         iblock = *pos >> sb->s_blocksize_bits;
 93         err = fat_bmap(dir, iblock, &phys, &mapped_blocks, 0);
 94         if (err || !phys)
 95                 return -1;      /* beyond EOF or error */
 96 
 97         fat_dir_readahead(dir, iblock, phys);
 98 
 99         *bh = sb_bread(sb, phys);
100         if (*bh == NULL) {
101                 fat_msg(sb, KERN_ERR, "Directory bread(block %llu) failed",
102                        (llu)phys);
103                 /* skip this block */
104                 *pos = (iblock + 1) << sb->s_blocksize_bits;
105                 goto next;
106         }
107 
108         offset = *pos & (sb->s_blocksize - 1);
109         *pos += sizeof(struct msdos_dir_entry);
110         *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
111 
112         return 0;
113 }
114 
115 static inline int fat_get_entry(struct inode *dir, loff_t *pos,
116                                 struct buffer_head **bh,
117                                 struct msdos_dir_entry **de)
118 {
119         /* Fast stuff first */
120         if (*bh && *de &&
121             (*de - (struct msdos_dir_entry *)(*bh)->b_data) < MSDOS_SB(dir->i_sb)->dir_per_block - 1) {
122                 *pos += sizeof(struct msdos_dir_entry);
123                 (*de)++;
124                 return 0;
125         }
126         return fat__get_entry(dir, pos, bh, de);
127 }
128 
129 /*
130  * Convert Unicode 16 to UTF-8, translated Unicode, or ASCII.
131  * If uni_xlate is enabled and we can't get a 1:1 conversion, use a
132  * colon as an escape character since it is normally invalid on the vfat
133  * filesystem. The following four characters are the hexadecimal digits
134  * of Unicode value. This lets us do a full dump and restore of Unicode
135  * filenames. We could get into some trouble with long Unicode names,
136  * but ignore that right now.
137  * Ahem... Stack smashing in ring 0 isn't fun. Fixed.
138  */
139 static int uni16_to_x8(struct super_block *sb, unsigned char *ascii,
140                        const wchar_t *uni, int len, struct nls_table *nls)
141 {
142         int uni_xlate = MSDOS_SB(sb)->options.unicode_xlate;
143         const wchar_t *ip;
144         wchar_t ec;
145         unsigned char *op;
146         int charlen;
147 
148         ip = uni;
149         op = ascii;
150 
151         while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {
152                 ec = *ip++;
153                 if ((charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE)) > 0) {
154                         op += charlen;
155                         len -= charlen;
156                 } else {
157                         if (uni_xlate == 1) {
158                                 *op++ = ':';
159                                 op = pack_hex_byte(op, ec >> 8);
160                                 op = pack_hex_byte(op, ec);
161                                 len -= 5;
162                         } else {
163                                 *op++ = '?';
164                                 len--;
165                         }
166                 }
167         }
168 
169         if (unlikely(*ip)) {
170                 fat_msg(sb, KERN_WARNING, "filename was truncated while "
171                         "converting.");
172         }
173 
174         *op = 0;
175         return (op - ascii);
176 }
177 
178 static inline int fat_uni_to_x8(struct super_block *sb, const wchar_t *uni,
179                                 unsigned char *buf, int size)
180 {
181         struct msdos_sb_info *sbi = MSDOS_SB(sb);
182         if (sbi->options.utf8)
183                 return utf16s_to_utf8s(uni, FAT_MAX_UNI_CHARS,
184                                 UTF16_HOST_ENDIAN, buf, size);
185         else
186                 return uni16_to_x8(sb, buf, uni, size, sbi->nls_io);
187 }
188 
189 static inline int
190 fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
191 {
192         int charlen;
193 
194         charlen = t->char2uni(c, clen, uni);
195         if (charlen < 0) {
196                 *uni = 0x003f;  /* a question mark */
197                 charlen = 1;
198         }
199         return charlen;
200 }
201 
202 static inline int
203 fat_short2lower_uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
204 {
205         int charlen;
206         wchar_t wc;
207 
208         charlen = t->char2uni(c, clen, &wc);
209         if (charlen < 0) {
210                 *uni = 0x003f;  /* a question mark */
211                 charlen = 1;
212         } else if (charlen <= 1) {
213                 unsigned char nc = t->charset2lower[*c];
214 
215                 if (!nc)
216                         nc = *c;
217 
218                 if ( (charlen = t->char2uni(&nc, 1, uni)) < 0) {
219                         *uni = 0x003f;  /* a question mark */
220                         charlen = 1;
221                 }
222         } else
223                 *uni = wc;
224 
225         return charlen;
226 }
227 
228 static inline int
229 fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size,
230                   wchar_t *uni_buf, unsigned short opt, int lower)
231 {
232         int len = 0;
233 
234         if (opt & VFAT_SFN_DISPLAY_LOWER)
235                 len =  fat_short2lower_uni(nls, buf, buf_size, uni_buf);
236         else if (opt & VFAT_SFN_DISPLAY_WIN95)
237                 len = fat_short2uni(nls, buf, buf_size, uni_buf);
238         else if (opt & VFAT_SFN_DISPLAY_WINNT) {
239                 if (lower)
240                         len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
241                 else
242                         len = fat_short2uni(nls, buf, buf_size, uni_buf);
243         } else
244                 len = fat_short2uni(nls, buf, buf_size, uni_buf);
245 
246         return len;
247 }
248 
249 static inline int fat_name_match(struct msdos_sb_info *sbi,
250                                  const unsigned char *a, int a_len,
251                                  const unsigned char *b, int b_len)
252 {
253         if (a_len != b_len)
254                 return 0;
255 
256         if (sbi->options.name_check != 's')
257                 return !nls_strnicmp(sbi->nls_io, a, b, a_len);
258         else
259                 return !memcmp(a, b, a_len);
260 }
261 
262 enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, };
263 
264 /**
265  * fat_parse_long - Parse extended directory entry.
266  *
267  * This function returns zero on success, negative value on error, or one of
268  * the following:
269  *
270  * %PARSE_INVALID - Directory entry is invalid.
271  * %PARSE_NOT_LONGNAME - Directory entry does not contain longname.
272  * %PARSE_EOF - Directory has no more entries.
273  */
274 static int fat_parse_long(struct inode *dir, loff_t *pos,
275                           struct buffer_head **bh, struct msdos_dir_entry **de,
276                           wchar_t **unicode, unsigned char *nr_slots)
277 {
278         struct msdos_dir_slot *ds;
279         unsigned char id, slot, slots, alias_checksum;
280 
281         if (!*unicode) {
282                 *unicode = __getname();
283                 if (!*unicode) {
284                         brelse(*bh);
285                         return -ENOMEM;
286                 }
287         }
288 parse_long:
289         slots = 0;
290         ds = (struct msdos_dir_slot *)*de;
291         id = ds->id;
292         if (!(id & 0x40))
293                 return PARSE_INVALID;
294         slots = id & ~0x40;
295         if (slots > 20 || !slots)       /* ceil(256 * 2 / 26) */
296                 return PARSE_INVALID;
297         *nr_slots = slots;
298         alias_checksum = ds->alias_checksum;
299 
300         slot = slots;
301         while (1) {
302                 int offset;
303 
304                 slot--;
305                 offset = slot * 13;
306                 fat16_towchar(*unicode + offset, ds->name0_4, 5);
307                 fat16_towchar(*unicode + offset + 5, ds->name5_10, 6);
308                 fat16_towchar(*unicode + offset + 11, ds->name11_12, 2);
309 
310                 if (ds->id & 0x40)
311                         (*unicode)[offset + 13] = 0;
312                 if (fat_get_entry(dir, pos, bh, de) < 0)
313                         return PARSE_EOF;
314                 if (slot == 0)
315                         break;
316                 ds = (struct msdos_dir_slot *)*de;
317                 if (ds->attr != ATTR_EXT)
318                         return PARSE_NOT_LONGNAME;
319                 if ((ds->id & ~0x40) != slot)
320                         goto parse_long;
321                 if (ds->alias_checksum != alias_checksum)
322                         goto parse_long;
323         }
324         if ((*de)->name[0] == DELETED_FLAG)
325                 return PARSE_INVALID;
326         if ((*de)->attr == ATTR_EXT)
327                 goto parse_long;
328         if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME))
329                 return PARSE_INVALID;
330         if (fat_checksum((*de)->name) != alias_checksum)
331                 *nr_slots = 0;
332 
333         return 0;
334 }
335 
336 /*
337  * Return values: negative -> error, 0 -> not found, positive -> found,
338  * value is the total amount of slots, including the shortname entry.
339  */
340 int fat_search_long(struct inode *inode, const unsigned char *name,
341                     int name_len, struct fat_slot_info *sinfo)
342 {
343         struct super_block *sb = inode->i_sb;
344         struct msdos_sb_info *sbi = MSDOS_SB(sb);
345         struct buffer_head *bh = NULL;
346         struct msdos_dir_entry *de;
347         struct nls_table *nls_disk = sbi->nls_disk;
348         unsigned char nr_slots;
349         wchar_t bufuname[14];
350         wchar_t *unicode = NULL;
351         unsigned char work[MSDOS_NAME];
352         unsigned char bufname[FAT_MAX_SHORT_SIZE];
353         unsigned short opt_shortname = sbi->options.shortname;
354         loff_t cpos = 0;
355         int chl, i, j, last_u, err, len;
356 
357         err = -ENOENT;
358         while (1) {
359                 if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
360                         goto end_of_dir;
361 parse_record:
362                 nr_slots = 0;
363                 if (de->name[0] == DELETED_FLAG)
364                         continue;
365                 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
366                         continue;
367                 if (de->attr != ATTR_EXT && IS_FREE(de->name))
368                         continue;
369                 if (de->attr == ATTR_EXT) {
370                         int status = fat_parse_long(inode, &cpos, &bh, &de,
371                                                     &unicode, &nr_slots);
372                         if (status < 0) {
373                                 err = status;
374                                 goto end_of_dir;
375                         } else if (status == PARSE_INVALID)
376                                 continue;
377                         else if (status == PARSE_NOT_LONGNAME)
378                                 goto parse_record;
379                         else if (status == PARSE_EOF)
380                                 goto end_of_dir;
381                 }
382 
383                 memcpy(work, de->name, sizeof(de->name));
384                 /* see namei.c, msdos_format_name */
385                 if (work[0] == 0x05)
386                         work[0] = 0xE5;
387                 for (i = 0, j = 0, last_u = 0; i < 8;) {
388                         if (!work[i])
389                                 break;
390                         chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
391                                                 &bufuname[j++], opt_shortname,
392                                                 de->lcase & CASE_LOWER_BASE);
393                         if (chl <= 1) {
394                                 if (work[i] != ' ')
395                                         last_u = j;
396                         } else {
397                                 last_u = j;
398                         }
399                         i += chl;
400                 }
401                 j = last_u;
402                 fat_short2uni(nls_disk, ".", 1, &bufuname[j++]);
403                 for (i = 8; i < MSDOS_NAME;) {
404                         if (!work[i])
405                                 break;
406                         chl = fat_shortname2uni(nls_disk, &work[i],
407                                                 MSDOS_NAME - i,
408                                                 &bufuname[j++], opt_shortname,
409                                                 de->lcase & CASE_LOWER_EXT);
410                         if (chl <= 1) {
411                                 if (work[i] != ' ')
412                                         last_u = j;
413                         } else {
414                                 last_u = j;
415                         }
416                         i += chl;
417                 }
418                 if (!last_u)
419                         continue;
420 
421                 /* Compare shortname */
422                 bufuname[last_u] = 0x0000;
423                 len = fat_uni_to_x8(sb, bufuname, bufname, sizeof(bufname));
424                 if (fat_name_match(sbi, name, name_len, bufname, len))
425                         goto found;
426 
427                 if (nr_slots) {
428                         void *longname = unicode + FAT_MAX_UNI_CHARS;
429                         int size = PATH_MAX - FAT_MAX_UNI_SIZE;
430 
431                         /* Compare longname */
432                         len = fat_uni_to_x8(sb, unicode, longname, size);
433                         if (fat_name_match(sbi, name, name_len, longname, len))
434                                 goto found;
435                 }
436         }
437 
438 found:
439         nr_slots++;     /* include the de */
440         sinfo->slot_off = cpos - nr_slots * sizeof(*de);
441         sinfo->nr_slots = nr_slots;
442         sinfo->de = de;
443         sinfo->bh = bh;
444         sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
445         err = 0;
446 end_of_dir:
447         if (unicode)
448                 __putname(unicode);
449 
450         return err;
451 }
452 
453 EXPORT_SYMBOL_GPL(fat_search_long);
454 
455 struct fat_ioctl_filldir_callback {
456         void __user *dirent;
457         int result;
458         /* for dir ioctl */
459         const char *longname;
460         int long_len;
461         const char *shortname;
462         int short_len;
463 };
464 
465 static int __fat_readdir(struct inode *inode, struct file *filp, void *dirent,
466                          filldir_t filldir, int short_only, int both)
467 {
468         struct super_block *sb = inode->i_sb;
469         struct msdos_sb_info *sbi = MSDOS_SB(sb);
470         struct buffer_head *bh;
471         struct msdos_dir_entry *de;
472         struct nls_table *nls_disk = sbi->nls_disk;
473         unsigned char nr_slots;
474         wchar_t bufuname[14];
475         wchar_t *unicode = NULL;
476         unsigned char c, work[MSDOS_NAME];
477         unsigned char bufname[FAT_MAX_SHORT_SIZE], *ptname = bufname;
478         unsigned short opt_shortname = sbi->options.shortname;
479         int isvfat = sbi->options.isvfat;
480         int nocase = sbi->options.nocase;
481         const char *fill_name = NULL;
482         unsigned long inum;
483         unsigned long lpos, dummy, *furrfu = &lpos;
484         loff_t cpos;
485         int chi, chl, i, i2, j, last, last_u, dotoffset = 0, fill_len = 0;
486         int ret = 0;
487 
488         lock_super(sb);
489 
490         cpos = filp->f_pos;
491         /* Fake . and .. for the root directory. */
492         if (inode->i_ino == MSDOS_ROOT_INO) {
493                 while (cpos < 2) {
494                         if (filldir(dirent, "..", cpos+1, cpos, MSDOS_ROOT_INO, DT_DIR) < 0)
495                                 goto out;
496                         cpos++;
497                         filp->f_pos++;
498                 }
499                 if (cpos == 2) {
500                         dummy = 2;
501                         furrfu = &dummy;
502                         cpos = 0;
503                 }
504         }
505         if (cpos & (sizeof(struct msdos_dir_entry) - 1)) {
506                 ret = -ENOENT;
507                 goto out;
508         }
509 
510         bh = NULL;
511 get_new:
512         if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
513                 goto end_of_dir;
514 parse_record:
515         nr_slots = 0;
516         /*
517          * Check for long filename entry, but if short_only, we don't
518          * need to parse long filename.
519          */
520         if (isvfat && !short_only) {
521                 if (de->name[0] == DELETED_FLAG)
522                         goto record_end;
523                 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
524                         goto record_end;
525                 if (de->attr != ATTR_EXT && IS_FREE(de->name))
526                         goto record_end;
527         } else {
528                 if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))
529                         goto record_end;
530         }
531 
532         if (isvfat && de->attr == ATTR_EXT) {
533                 int status = fat_parse_long(inode, &cpos, &bh, &de,
534                                             &unicode, &nr_slots);
535                 if (status < 0) {
536                         filp->f_pos = cpos;
537                         ret = status;
538                         goto out;
539                 } else if (status == PARSE_INVALID)
540                         goto record_end;
541                 else if (status == PARSE_NOT_LONGNAME)
542                         goto parse_record;
543                 else if (status == PARSE_EOF)
544                         goto end_of_dir;
545 
546                 if (nr_slots) {
547                         void *longname = unicode + FAT_MAX_UNI_CHARS;
548                         int size = PATH_MAX - FAT_MAX_UNI_SIZE;
549                         int len = fat_uni_to_x8(sb, unicode, longname, size);
550 
551                         fill_name = longname;
552                         fill_len = len;
553                         /* !both && !short_only, so we don't need shortname. */
554                         if (!both)
555                                 goto start_filldir;
556                 }
557         }
558 
559         if (sbi->options.dotsOK) {
560                 ptname = bufname;
561                 dotoffset = 0;
562                 if (de->attr & ATTR_HIDDEN) {
563                         *ptname++ = '.';
564                         dotoffset = 1;
565                 }
566         }
567 
568         memcpy(work, de->name, sizeof(de->name));
569         /* see namei.c, msdos_format_name */
570         if (work[0] == 0x05)
571                 work[0] = 0xE5;
572         for (i = 0, j = 0, last = 0, last_u = 0; i < 8;) {
573                 if (!(c = work[i]))
574                         break;
575                 chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
576                                         &bufuname[j++], opt_shortname,
577                                         de->lcase & CASE_LOWER_BASE);
578                 if (chl <= 1) {
579                         ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c;
580                         if (c != ' ') {
581                                 last = i;
582                                 last_u = j;
583                         }
584                 } else {
585                         last_u = j;
586                         for (chi = 0; chi < chl && i < 8; chi++) {
587                                 ptname[i] = work[i];
588                                 i++; last = i;
589                         }
590                 }
591         }
592         i = last;
593         j = last_u;
594         fat_short2uni(nls_disk, ".", 1, &bufuname[j++]);
595         ptname[i++] = '.';
596         for (i2 = 8; i2 < MSDOS_NAME;) {
597                 if (!(c = work[i2]))
598                         break;
599                 chl = fat_shortname2uni(nls_disk, &work[i2], MSDOS_NAME - i2,
600                                         &bufuname[j++], opt_shortname,
601                                         de->lcase & CASE_LOWER_EXT);
602                 if (chl <= 1) {
603                         i2++;
604                         ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c;
605                         if (c != ' ') {
606                                 last = i;
607                                 last_u = j;
608                         }
609                 } else {
610                         last_u = j;
611                         for (chi = 0; chi < chl && i2 < MSDOS_NAME; chi++) {
612                                 ptname[i++] = work[i2++];
613                                 last = i;
614                         }
615                 }
616         }
617         if (!last)
618                 goto record_end;
619 
620         i = last + dotoffset;
621         j = last_u;
622 
623         if (isvfat) {
624                 bufuname[j] = 0x0000;
625                 i = fat_uni_to_x8(sb, bufuname, bufname, sizeof(bufname));
626         }
627         if (nr_slots) {
628                 /* hack for fat_ioctl_filldir() */
629                 struct fat_ioctl_filldir_callback *p = dirent;
630 
631                 p->longname = fill_name;
632                 p->long_len = fill_len;
633                 p->shortname = bufname;
634                 p->short_len = i;
635                 fill_name = NULL;
636                 fill_len = 0;
637         } else {
638                 fill_name = bufname;
639                 fill_len = i;
640         }
641 
642 start_filldir:
643         lpos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
644         if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME))
645                 inum = inode->i_ino;
646         else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
647                 inum = parent_ino(filp->f_path.dentry);
648         } else {
649                 loff_t i_pos = fat_make_i_pos(sb, bh, de);
650                 struct inode *tmp = fat_iget(sb, i_pos);
651                 if (tmp) {
652                         inum = tmp->i_ino;
653                         iput(tmp);
654                 } else
655                         inum = iunique(sb, MSDOS_ROOT_INO);
656         }
657 
658         if (filldir(dirent, fill_name, fill_len, *furrfu, inum,
659                     (de->attr & ATTR_DIR) ? DT_DIR : DT_REG) < 0)
660                 goto fill_failed;
661 
662 record_end:
663         furrfu = &lpos;
664         filp->f_pos = cpos;
665         goto get_new;
666 end_of_dir:
667         filp->f_pos = cpos;
668 fill_failed:
669         brelse(bh);
670         if (unicode)
671                 __putname(unicode);
672 out:
673         unlock_super(sb);
674         return ret;
675 }
676 
677 static int fat_readdir(struct file *filp, void *dirent, filldir_t filldir)
678 {
679         struct inode *inode = filp->f_path.dentry->d_inode;
680         return __fat_readdir(inode, filp, dirent, filldir, 0, 0);
681 }
682 
683 #define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type)                          \
684 static int func(void *__buf, const char *name, int name_len,               \
685                              loff_t offset, u64 ino, unsigned int d_type)  \
686 {                                                                          \
687         struct fat_ioctl_filldir_callback *buf = __buf;                    \
688         struct dirent_type __user *d1 = buf->dirent;                       \
689         struct dirent_type __user *d2 = d1 + 1;                            \
690                                                                            \
691         if (buf->result)                                                   \
692                 return -EINVAL;                                            \
693         buf->result++;                                                     \
694                                                                            \
695         if (name != NULL) {                                                \
696                 /* dirent has only short name */                           \
697                 if (name_len >= sizeof(d1->d_name))                        \
698                         name_len = sizeof(d1->d_name) - 1;                 \
699                                                                            \
700                 if (put_user(0, d2->d_name)                     ||         \
701                     put_user(0, &d2->d_reclen)                  ||         \
702                     copy_to_user(d1->d_name, name, name_len)    ||         \
703                     put_user(0, d1->d_name + name_len)          ||         \
704                     put_user(name_len, &d1->d_reclen))                     \
705                         goto efault;                                       \
706         } else {                                                           \
707                 /* dirent has short and long name */                       \
708                 const char *longname = buf->longname;                      \
709                 int long_len = buf->long_len;                              \
710                 const char *shortname = buf->shortname;                    \
711                 int short_len = buf->short_len;                            \
712                                                                            \
713                 if (long_len >= sizeof(d1->d_name))                        \
714                         long_len = sizeof(d1->d_name) - 1;                 \
715                 if (short_len >= sizeof(d1->d_name))                       \
716                         short_len = sizeof(d1->d_name) - 1;                \
717                                                                            \
718                 if (copy_to_user(d2->d_name, longname, long_len)        || \
719                     put_user(0, d2->d_name + long_len)                  || \
720                     put_user(long_len, &d2->d_reclen)                   || \
721                     put_user(ino, &d2->d_ino)                           || \
722                     put_user(offset, &d2->d_off)                        || \
723                     copy_to_user(d1->d_name, shortname, short_len)      || \
724                     put_user(0, d1->d_name + short_len)                 || \
725                     put_user(short_len, &d1->d_reclen))                    \
726                         goto efault;                                       \
727         }                                                                  \
728         return 0;                                                          \
729 efault:                                                                    \
730         buf->result = -EFAULT;                                             \
731         return -EFAULT;                                                    \
732 }
733 
734 FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)
735 
736 static int fat_ioctl_readdir(struct inode *inode, struct file *filp,
737                              void __user *dirent, filldir_t filldir,
738                              int short_only, int both)
739 {
740         struct fat_ioctl_filldir_callback buf;
741         int ret;
742 
743         buf.dirent = dirent;
744         buf.result = 0;
745         mutex_lock(&inode->i_mutex);
746         ret = -ENOENT;
747         if (!IS_DEADDIR(inode)) {
748                 ret = __fat_readdir(inode, filp, &buf, filldir,
749                                     short_only, both);
750         }
751         mutex_unlock(&inode->i_mutex);
752         if (ret >= 0)
753                 ret = buf.result;
754         return ret;
755 }
756 
757 static long fat_dir_ioctl(struct file *filp, unsigned int cmd,
758                           unsigned long arg)
759 {
760         struct inode *inode = filp->f_path.dentry->d_inode;
761         struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg;
762         int short_only, both;
763 
764         switch (cmd) {
765         case VFAT_IOCTL_READDIR_SHORT:
766                 short_only = 1;
767                 both = 0;
768                 break;
769         case VFAT_IOCTL_READDIR_BOTH:
770                 short_only = 0;
771                 both = 1;
772                 break;
773         default:
774                 return fat_generic_ioctl(filp, cmd, arg);
775         }
776 
777         if (!access_ok(VERIFY_WRITE, d1, sizeof(struct __fat_dirent[2])))
778                 return -EFAULT;
779         /*
780          * Yes, we don't need this put_user() absolutely. However old
781          * code didn't return the right value. So, app use this value,
782          * in order to check whether it is EOF.
783          */
784         if (put_user(0, &d1->d_reclen))
785                 return -EFAULT;
786 
787         return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir,
788                                  short_only, both);
789 }
790 
791 #ifdef CONFIG_COMPAT
792 #define VFAT_IOCTL_READDIR_BOTH32       _IOR('r', 1, struct compat_dirent[2])
793 #define VFAT_IOCTL_READDIR_SHORT32      _IOR('r', 2, struct compat_dirent[2])
794 
795 FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent)
796 
797 static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd,
798                                  unsigned long arg)
799 {
800         struct inode *inode = filp->f_path.dentry->d_inode;
801         struct compat_dirent __user *d1 = compat_ptr(arg);
802         int short_only, both;
803 
804         switch (cmd) {
805         case VFAT_IOCTL_READDIR_SHORT32:
806                 short_only = 1;
807                 both = 0;
808                 break;
809         case VFAT_IOCTL_READDIR_BOTH32:
810                 short_only = 0;
811                 both = 1;
812                 break;
813         default:
814                 return fat_generic_ioctl(filp, cmd, (unsigned long)arg);
815         }
816 
817         if (!access_ok(VERIFY_WRITE, d1, sizeof(struct compat_dirent[2])))
818                 return -EFAULT;
819         /*
820          * Yes, we don't need this put_user() absolutely. However old
821          * code didn't return the right value. So, app use this value,
822          * in order to check whether it is EOF.
823          */
824         if (put_user(0, &d1->d_reclen))
825                 return -EFAULT;
826 
827         return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir,
828                                  short_only, both);
829 }
830 #endif /* CONFIG_COMPAT */
831 
832 const struct file_operations fat_dir_operations = {
833         .llseek         = generic_file_llseek,
834         .read           = generic_read_dir,
835         .readdir        = fat_readdir,
836         .unlocked_ioctl = fat_dir_ioctl,
837 #ifdef CONFIG_COMPAT
838         .compat_ioctl   = fat_compat_dir_ioctl,
839 #endif
840         .fsync          = fat_file_fsync,
841 };
842 
843 static int fat_get_short_entry(struct inode *dir, loff_t *pos,
844                                struct buffer_head **bh,
845                                struct msdos_dir_entry **de)
846 {
847         while (fat_get_entry(dir, pos, bh, de) >= 0) {
848                 /* free entry or long name entry or volume label */
849                 if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))
850                         return 0;
851         }
852         return -ENOENT;
853 }
854 
855 /*
856  * The ".." entry can not provide the "struct fat_slot_info" informations
857  * for inode. So, this function provide the some informations only.
858  */
859 int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
860                          struct msdos_dir_entry **de, loff_t *i_pos)
861 {
862         loff_t offset;
863 
864         offset = 0;
865         *bh = NULL;
866         while (fat_get_short_entry(dir, &offset, bh, de) >= 0) {
867                 if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME)) {
868                         *i_pos = fat_make_i_pos(dir->i_sb, *bh, *de);
869                         return 0;
870                 }
871         }
872         return -ENOENT;
873 }
874 
875 EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);
876 
877 /* See if directory is empty */
878 int fat_dir_empty(struct inode *dir)
879 {
880         struct buffer_head *bh;
881         struct msdos_dir_entry *de;
882         loff_t cpos;
883         int result = 0;
884 
885         bh = NULL;
886         cpos = 0;
887         while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
888                 if (strncmp(de->name, MSDOS_DOT   , MSDOS_NAME) &&
889                     strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
890                         result = -ENOTEMPTY;
891                         break;
892                 }
893         }
894         brelse(bh);
895         return result;
896 }
897 
898 EXPORT_SYMBOL_GPL(fat_dir_empty);
899 
900 /*
901  * fat_subdirs counts the number of sub-directories of dir. It can be run
902  * on directories being created.
903  */
904 int fat_subdirs(struct inode *dir)
905 {
906         struct buffer_head *bh;
907         struct msdos_dir_entry *de;
908         loff_t cpos;
909         int count = 0;
910 
911         bh = NULL;
912         cpos = 0;
913         while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
914                 if (de->attr & ATTR_DIR)
915                         count++;
916         }
917         brelse(bh);
918         return count;
919 }
920 
921 /*
922  * Scans a directory for a given file (name points to its formatted name).
923  * Returns an error code or zero.
924  */
925 int fat_scan(struct inode *dir, const unsigned char *name,
926              struct fat_slot_info *sinfo)
927 {
928         struct super_block *sb = dir->i_sb;
929 
930         sinfo->slot_off = 0;
931         sinfo->bh = NULL;
932         while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
933                                    &sinfo->de) >= 0) {
934                 if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) {
935                         sinfo->slot_off -= sizeof(*sinfo->de);
936                         sinfo->nr_slots = 1;
937                         sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
938                         return 0;
939                 }
940         }
941         return -ENOENT;
942 }
943 
944 EXPORT_SYMBOL_GPL(fat_scan);
945 
946 static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)
947 {
948         struct super_block *sb = dir->i_sb;
949         struct buffer_head *bh;
950         struct msdos_dir_entry *de, *endp;
951         int err = 0, orig_slots;
952 
953         while (nr_slots) {
954                 bh = NULL;
955                 if (fat_get_entry(dir, &pos, &bh, &de) < 0) {
956                         err = -EIO;
957                         break;
958                 }
959 
960                 orig_slots = nr_slots;
961                 endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize);
962                 while (nr_slots && de < endp) {
963                         de->name[0] = DELETED_FLAG;
964                         de++;
965                         nr_slots--;
966                 }
967                 mark_buffer_dirty_inode(bh, dir);
968                 if (IS_DIRSYNC(dir))
969                         err = sync_dirty_buffer(bh);
970                 brelse(bh);
971                 if (err)
972                         break;
973 
974                 /* pos is *next* de's position, so this does `- sizeof(de)' */
975                 pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de);
976         }
977 
978         return err;
979 }
980 
981 int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)
982 {
983         struct super_block *sb = dir->i_sb;
984         struct msdos_dir_entry *de;
985         struct buffer_head *bh;
986         int err = 0, nr_slots;
987 
988         /*
989          * First stage: Remove the shortname. By this, the directory
990          * entry is removed.
991          */
992         nr_slots = sinfo->nr_slots;
993         de = sinfo->de;
994         sinfo->de = NULL;
995         bh = sinfo->bh;
996         sinfo->bh = NULL;
997         while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) {
998                 de->name[0] = DELETED_FLAG;
999                 de--;
1000                 nr_slots--;
1001         }
1002         mark_buffer_dirty_inode(bh, dir);
1003         if (IS_DIRSYNC(dir))
1004                 err = sync_dirty_buffer(bh);
1005         brelse(bh);
1006         if (err)
1007                 return err;
1008         dir->i_version++;
1009 
1010         if (nr_slots) {
1011                 /*
1012                  * Second stage: remove the remaining longname slots.
1013                  * (This directory entry is already removed, and so return
1014                  * the success)
1015                  */
1016                 err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots);
1017                 if (err) {
1018                         fat_msg(sb, KERN_WARNING,
1019                                "Couldn't remove the long name slots");
1020                 }
1021         }
1022 
1023         dir->i_mtime = dir->i_atime = CURRENT_TIME_SEC;
1024         if (IS_DIRSYNC(dir))
1025                 (void)fat_sync_inode(dir);
1026         else
1027                 mark_inode_dirty(dir);
1028 
1029         return 0;
1030 }
1031 
1032 EXPORT_SYMBOL_GPL(fat_remove_entries);
1033 
1034 static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,
1035                               struct buffer_head **bhs, int nr_bhs)
1036 {
1037         struct super_block *sb = dir->i_sb;
1038         sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus;
1039         int err, i, n;
1040 
1041         /* Zeroing the unused blocks on this cluster */
1042         blknr += nr_used;
1043         n = nr_used;
1044         while (blknr < last_blknr) {
1045                 bhs[n] = sb_getblk(sb, blknr);
1046                 if (!bhs[n]) {
1047                         err = -ENOMEM;
1048                         goto error;
1049                 }
1050                 memset(bhs[n]->b_data, 0, sb->s_blocksize);
1051                 set_buffer_uptodate(bhs[n]);
1052                 mark_buffer_dirty_inode(bhs[n], dir);
1053 
1054                 n++;
1055                 blknr++;
1056                 if (n == nr_bhs) {
1057                         if (IS_DIRSYNC(dir)) {
1058                                 err = fat_sync_bhs(bhs, n);
1059                                 if (err)
1060                                         goto error;
1061                         }
1062                         for (i = 0; i < n; i++)
1063                                 brelse(bhs[i]);
1064                         n = 0;
1065                 }
1066         }
1067         if (IS_DIRSYNC(dir)) {
1068                 err = fat_sync_bhs(bhs, n);
1069                 if (err)
1070                         goto error;
1071         }
1072         for (i = 0; i < n; i++)
1073                 brelse(bhs[i]);
1074 
1075         return 0;
1076 
1077 error:
1078         for (i = 0; i < n; i++)
1079                 bforget(bhs[i]);
1080         return err;
1081 }
1082 
1083 int fat_alloc_new_dir(struct inode *dir, struct timespec *ts)
1084 {
1085         struct super_block *sb = dir->i_sb;
1086         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1087         struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1088         struct msdos_dir_entry *de;
1089         sector_t blknr;
1090         __le16 date, time;
1091         u8 time_cs;
1092         int err, cluster;
1093 
1094         err = fat_alloc_clusters(dir, &cluster, 1);
1095         if (err)
1096                 goto error;
1097 
1098         blknr = fat_clus_to_blknr(sbi, cluster);
1099         bhs[0] = sb_getblk(sb, blknr);
1100         if (!bhs[0]) {
1101                 err = -ENOMEM;
1102                 goto error_free;
1103         }
1104 
1105         fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
1106 
1107         de = (struct msdos_dir_entry *)bhs[0]->b_data;
1108         /* filling the new directory slots ("." and ".." entries) */
1109         memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME);
1110         memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME);
1111         de->attr = de[1].attr = ATTR_DIR;
1112         de[0].lcase = de[1].lcase = 0;
1113         de[0].time = de[1].time = time;
1114         de[0].date = de[1].date = date;
1115         if (sbi->options.isvfat) {
1116                 /* extra timestamps */
1117                 de[0].ctime = de[1].ctime = time;
1118                 de[0].ctime_cs = de[1].ctime_cs = time_cs;
1119                 de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date;
1120         } else {
1121                 de[0].ctime = de[1].ctime = 0;
1122                 de[0].ctime_cs = de[1].ctime_cs = 0;
1123                 de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0;
1124         }
1125         de[0].start = cpu_to_le16(cluster);
1126         de[0].starthi = cpu_to_le16(cluster >> 16);
1127         de[1].start = cpu_to_le16(MSDOS_I(dir)->i_logstart);
1128         de[1].starthi = cpu_to_le16(MSDOS_I(dir)->i_logstart >> 16);
1129         de[0].size = de[1].size = 0;
1130         memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));
1131         set_buffer_uptodate(bhs[0]);
1132         mark_buffer_dirty_inode(bhs[0], dir);
1133 
1134         err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE);
1135         if (err)
1136                 goto error_free;
1137 
1138         return cluster;
1139 
1140 error_free:
1141         fat_free_clusters(dir, cluster);
1142 error:
1143         return err;
1144 }
1145 
1146 EXPORT_SYMBOL_GPL(fat_alloc_new_dir);
1147 
1148 static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,
1149                                int *nr_cluster, struct msdos_dir_entry **de,
1150                                struct buffer_head **bh, loff_t *i_pos)
1151 {
1152         struct super_block *sb = dir->i_sb;
1153         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1154         struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1155         sector_t blknr, start_blknr, last_blknr;
1156         unsigned long size, copy;
1157         int err, i, n, offset, cluster[2];
1158 
1159         /*
1160          * The minimum cluster size is 512bytes, and maximum entry
1161          * size is 32*slots (672bytes).  So, iff the cluster size is
1162          * 512bytes, we may need two clusters.
1163          */
1164         size = nr_slots * sizeof(struct msdos_dir_entry);
1165         *nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits;
1166         BUG_ON(*nr_cluster > 2);
1167 
1168         err = fat_alloc_clusters(dir, cluster, *nr_cluster);
1169         if (err)
1170                 goto error;
1171 
1172         /*
1173          * First stage: Fill the directory entry.  NOTE: This cluster
1174          * is not referenced from any inode yet, so updates order is
1175          * not important.
1176          */
1177         i = n = copy = 0;
1178         do {
1179                 start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]);
1180                 last_blknr = start_blknr + sbi->sec_per_clus;
1181                 while (blknr < last_blknr) {
1182                         bhs[n] = sb_getblk(sb, blknr);
1183                         if (!bhs[n]) {
1184                                 err = -ENOMEM;
1185                                 goto error_nomem;
1186                         }
1187 
1188                         /* fill the directory entry */
1189                         copy = min(size, sb->s_blocksize);
1190                         memcpy(bhs[n]->b_data, slots, copy);
1191                         slots += copy;
1192                         size -= copy;
1193                         set_buffer_uptodate(bhs[n]);
1194                         mark_buffer_dirty_inode(bhs[n], dir);
1195                         if (!size)
1196                                 break;
1197                         n++;
1198                         blknr++;
1199                 }
1200         } while (++i < *nr_cluster);
1201 
1202         memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy);
1203         offset = copy - sizeof(struct msdos_dir_entry);
1204         get_bh(bhs[n]);
1205         *bh = bhs[n];
1206         *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
1207         *i_pos = fat_make_i_pos(sb, *bh, *de);
1208 
1209         /* Second stage: clear the rest of cluster, and write outs */
1210         err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE);
1211         if (err)
1212                 goto error_free;
1213 
1214         return cluster[0];
1215 
1216 error_free:
1217         brelse(*bh);
1218         *bh = NULL;
1219         n = 0;
1220 error_nomem:
1221         for (i = 0; i < n; i++)
1222                 bforget(bhs[i]);
1223         fat_free_clusters(dir, cluster[0]);
1224 error:
1225         return err;
1226 }
1227 
1228 int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
1229                     struct fat_slot_info *sinfo)
1230 {
1231         struct super_block *sb = dir->i_sb;
1232         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1233         struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */
1234         struct msdos_dir_entry *de;
1235         int err, free_slots, i, nr_bhs;
1236         loff_t pos, i_pos;
1237 
1238         sinfo->nr_slots = nr_slots;
1239 
1240         /* First stage: search free direcotry entries */
1241         free_slots = nr_bhs = 0;
1242         bh = prev = NULL;
1243         pos = 0;
1244         err = -ENOSPC;
1245         while (fat_get_entry(dir, &pos, &bh, &de) > -1) {
1246                 /* check the maximum size of directory */
1247                 if (pos >= FAT_MAX_DIR_SIZE)
1248                         goto error;
1249 
1250                 if (IS_FREE(de->name)) {
1251                         if (prev != bh) {
1252                                 get_bh(bh);
1253                                 bhs[nr_bhs] = prev = bh;
1254                                 nr_bhs++;
1255                         }
1256                         free_slots++;
1257                         if (free_slots == nr_slots)
1258                                 goto found;
1259                 } else {
1260                         for (i = 0; i < nr_bhs; i++)
1261                                 brelse(bhs[i]);
1262                         prev = NULL;
1263                         free_slots = nr_bhs = 0;
1264                 }
1265         }
1266         if (dir->i_ino == MSDOS_ROOT_INO) {
1267                 if (sbi->fat_bits != 32)
1268                         goto error;
1269         } else if (MSDOS_I(dir)->i_start == 0) {
1270                 fat_msg(sb, KERN_ERR, "Corrupted directory (i_pos %lld)",
1271                        MSDOS_I(dir)->i_pos);
1272                 err = -EIO;
1273                 goto error;
1274         }
1275 
1276 found:
1277         err = 0;
1278         pos -= free_slots * sizeof(*de);
1279         nr_slots -= free_slots;
1280         if (free_slots) {
1281                 /*
1282                  * Second stage: filling the free entries with new entries.
1283                  * NOTE: If this slots has shortname, first, we write
1284                  * the long name slots, then write the short name.
1285                  */
1286                 int size = free_slots * sizeof(*de);
1287                 int offset = pos & (sb->s_blocksize - 1);
1288                 int long_bhs = nr_bhs - (nr_slots == 0);
1289 
1290                 /* Fill the long name slots. */
1291                 for (i = 0; i < long_bhs; i++) {
1292                         int copy = min_t(int, sb->s_blocksize - offset, size);
1293                         memcpy(bhs[i]->b_data + offset, slots, copy);
1294                         mark_buffer_dirty_inode(bhs[i], dir);
1295                         offset = 0;
1296                         slots += copy;
1297                         size -= copy;
1298                 }
1299                 if (long_bhs && IS_DIRSYNC(dir))
1300                         err = fat_sync_bhs(bhs, long_bhs);
1301                 if (!err && i < nr_bhs) {
1302                         /* Fill the short name slot. */
1303                         int copy = min_t(int, sb->s_blocksize - offset, size);
1304                         memcpy(bhs[i]->b_data + offset, slots, copy);
1305                         mark_buffer_dirty_inode(bhs[i], dir);
1306                         if (IS_DIRSYNC(dir))
1307                                 err = sync_dirty_buffer(bhs[i]);
1308                 }
1309                 for (i = 0; i < nr_bhs; i++)
1310                         brelse(bhs[i]);
1311                 if (err)
1312                         goto error_remove;
1313         }
1314 
1315         if (nr_slots) {
1316                 int cluster, nr_cluster;
1317 
1318                 /*
1319                  * Third stage: allocate the cluster for new entries.
1320                  * And initialize the cluster with new entries, then
1321                  * add the cluster to dir.
1322                  */
1323                 cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster,
1324                                               &de, &bh, &i_pos);
1325                 if (cluster < 0) {
1326                         err = cluster;
1327                         goto error_remove;
1328                 }
1329                 err = fat_chain_add(dir, cluster, nr_cluster);
1330                 if (err) {
1331                         fat_free_clusters(dir, cluster);
1332                         goto error_remove;
1333                 }
1334                 if (dir->i_size & (sbi->cluster_size - 1)) {
1335                         fat_fs_error(sb, "Odd directory size");
1336                         dir->i_size = (dir->i_size + sbi->cluster_size - 1)
1337                                 & ~((loff_t)sbi->cluster_size - 1);
1338                 }
1339                 dir->i_size += nr_cluster << sbi->cluster_bits;
1340                 MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits;
1341         }
1342         sinfo->slot_off = pos;
1343         sinfo->de = de;
1344         sinfo->bh = bh;
1345         sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
1346 
1347         return 0;
1348 
1349 error:
1350         brelse(bh);
1351         for (i = 0; i < nr_bhs; i++)
1352                 brelse(bhs[i]);
1353         return err;
1354 
1355 error_remove:
1356         brelse(bh);
1357         if (free_slots)
1358                 __fat_remove_entries(dir, pos, free_slots);
1359         return err;
1360 }
1361 
1362 EXPORT_SYMBOL_GPL(fat_add_entries);
1363 

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