Version:  2.0.40 2.2.26 2.4.37 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9

Linux/fs/fat/namei_vfat.c

  1 /*
  2  *  linux/fs/vfat/namei.c
  3  *
  4  *  Written 1992,1993 by Werner Almesberger
  5  *
  6  *  Windows95/Windows NT compatible extended MSDOS filesystem
  7  *    by Gordon Chaffee Copyright (C) 1995.  Send bug reports for the
  8  *    VFAT filesystem to <chaffee@cs.berkeley.edu>.  Specify
  9  *    what file operation caused you trouble and if you can duplicate
 10  *    the problem, send a script that demonstrates it.
 11  *
 12  *  Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>
 13  *
 14  *  Support Multibyte characters and cleanup by
 15  *                              OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
 16  */
 17 
 18 #include <linux/module.h>
 19 #include <linux/ctype.h>
 20 #include <linux/slab.h>
 21 #include <linux/namei.h>
 22 #include "fat.h"
 23 
 24 static inline unsigned long vfat_d_version(struct dentry *dentry)
 25 {
 26         return (unsigned long) dentry->d_fsdata;
 27 }
 28 
 29 static inline void vfat_d_version_set(struct dentry *dentry,
 30                                       unsigned long version)
 31 {
 32         dentry->d_fsdata = (void *) version;
 33 }
 34 
 35 /*
 36  * If new entry was created in the parent, it could create the 8.3
 37  * alias (the shortname of logname).  So, the parent may have the
 38  * negative-dentry which matches the created 8.3 alias.
 39  *
 40  * If it happened, the negative dentry isn't actually negative
 41  * anymore.  So, drop it.
 42  */
 43 static int vfat_revalidate_shortname(struct dentry *dentry)
 44 {
 45         int ret = 1;
 46         spin_lock(&dentry->d_lock);
 47         if (vfat_d_version(dentry) != d_inode(dentry->d_parent)->i_version)
 48                 ret = 0;
 49         spin_unlock(&dentry->d_lock);
 50         return ret;
 51 }
 52 
 53 static int vfat_revalidate(struct dentry *dentry, unsigned int flags)
 54 {
 55         if (flags & LOOKUP_RCU)
 56                 return -ECHILD;
 57 
 58         /* This is not negative dentry. Always valid. */
 59         if (d_really_is_positive(dentry))
 60                 return 1;
 61         return vfat_revalidate_shortname(dentry);
 62 }
 63 
 64 static int vfat_revalidate_ci(struct dentry *dentry, unsigned int flags)
 65 {
 66         if (flags & LOOKUP_RCU)
 67                 return -ECHILD;
 68 
 69         /*
 70          * This is not negative dentry. Always valid.
 71          *
 72          * Note, rename() to existing directory entry will have ->d_inode,
 73          * and will use existing name which isn't specified name by user.
 74          *
 75          * We may be able to drop this positive dentry here. But dropping
 76          * positive dentry isn't good idea. So it's unsupported like
 77          * rename("filename", "FILENAME") for now.
 78          */
 79         if (d_really_is_positive(dentry))
 80                 return 1;
 81 
 82         /*
 83          * This may be nfsd (or something), anyway, we can't see the
 84          * intent of this. So, since this can be for creation, drop it.
 85          */
 86         if (!flags)
 87                 return 0;
 88 
 89         /*
 90          * Drop the negative dentry, in order to make sure to use the
 91          * case sensitive name which is specified by user if this is
 92          * for creation.
 93          */
 94         if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
 95                 return 0;
 96 
 97         return vfat_revalidate_shortname(dentry);
 98 }
 99 
100 /* returns the length of a struct qstr, ignoring trailing dots */
101 static unsigned int __vfat_striptail_len(unsigned int len, const char *name)
102 {
103         while (len && name[len - 1] == '.')
104                 len--;
105         return len;
106 }
107 
108 static unsigned int vfat_striptail_len(const struct qstr *qstr)
109 {
110         return __vfat_striptail_len(qstr->len, qstr->name);
111 }
112 
113 /*
114  * Compute the hash for the vfat name corresponding to the dentry.
115  * Note: if the name is invalid, we leave the hash code unchanged so
116  * that the existing dentry can be used. The vfat fs routines will
117  * return ENOENT or EINVAL as appropriate.
118  */
119 static int vfat_hash(const struct dentry *dentry, struct qstr *qstr)
120 {
121         qstr->hash = full_name_hash(dentry, qstr->name, vfat_striptail_len(qstr));
122         return 0;
123 }
124 
125 /*
126  * Compute the hash for the vfat name corresponding to the dentry.
127  * Note: if the name is invalid, we leave the hash code unchanged so
128  * that the existing dentry can be used. The vfat fs routines will
129  * return ENOENT or EINVAL as appropriate.
130  */
131 static int vfat_hashi(const struct dentry *dentry, struct qstr *qstr)
132 {
133         struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io;
134         const unsigned char *name;
135         unsigned int len;
136         unsigned long hash;
137 
138         name = qstr->name;
139         len = vfat_striptail_len(qstr);
140 
141         hash = init_name_hash(dentry);
142         while (len--)
143                 hash = partial_name_hash(nls_tolower(t, *name++), hash);
144         qstr->hash = end_name_hash(hash);
145 
146         return 0;
147 }
148 
149 /*
150  * Case insensitive compare of two vfat names.
151  */
152 static int vfat_cmpi(const struct dentry *dentry,
153                 unsigned int len, const char *str, const struct qstr *name)
154 {
155         struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io;
156         unsigned int alen, blen;
157 
158         /* A filename cannot end in '.' or we treat it like it has none */
159         alen = vfat_striptail_len(name);
160         blen = __vfat_striptail_len(len, str);
161         if (alen == blen) {
162                 if (nls_strnicmp(t, name->name, str, alen) == 0)
163                         return 0;
164         }
165         return 1;
166 }
167 
168 /*
169  * Case sensitive compare of two vfat names.
170  */
171 static int vfat_cmp(const struct dentry *dentry,
172                 unsigned int len, const char *str, const struct qstr *name)
173 {
174         unsigned int alen, blen;
175 
176         /* A filename cannot end in '.' or we treat it like it has none */
177         alen = vfat_striptail_len(name);
178         blen = __vfat_striptail_len(len, str);
179         if (alen == blen) {
180                 if (strncmp(name->name, str, alen) == 0)
181                         return 0;
182         }
183         return 1;
184 }
185 
186 static const struct dentry_operations vfat_ci_dentry_ops = {
187         .d_revalidate   = vfat_revalidate_ci,
188         .d_hash         = vfat_hashi,
189         .d_compare      = vfat_cmpi,
190 };
191 
192 static const struct dentry_operations vfat_dentry_ops = {
193         .d_revalidate   = vfat_revalidate,
194         .d_hash         = vfat_hash,
195         .d_compare      = vfat_cmp,
196 };
197 
198 /* Characters that are undesirable in an MS-DOS file name */
199 
200 static inline wchar_t vfat_bad_char(wchar_t w)
201 {
202         return (w < 0x0020)
203             || (w == '*') || (w == '?') || (w == '<') || (w == '>')
204             || (w == '|') || (w == '"') || (w == ':') || (w == '/')
205             || (w == '\\');
206 }
207 
208 static inline wchar_t vfat_replace_char(wchar_t w)
209 {
210         return (w == '[') || (w == ']') || (w == ';') || (w == ',')
211             || (w == '+') || (w == '=');
212 }
213 
214 static wchar_t vfat_skip_char(wchar_t w)
215 {
216         return (w == '.') || (w == ' ');
217 }
218 
219 static inline int vfat_is_used_badchars(const wchar_t *s, int len)
220 {
221         int i;
222 
223         for (i = 0; i < len; i++)
224                 if (vfat_bad_char(s[i]))
225                         return -EINVAL;
226 
227         if (s[i - 1] == ' ') /* last character cannot be space */
228                 return -EINVAL;
229 
230         return 0;
231 }
232 
233 static int vfat_find_form(struct inode *dir, unsigned char *name)
234 {
235         struct fat_slot_info sinfo;
236         int err = fat_scan(dir, name, &sinfo);
237         if (err)
238                 return -ENOENT;
239         brelse(sinfo.bh);
240         return 0;
241 }
242 
243 /*
244  * 1) Valid characters for the 8.3 format alias are any combination of
245  * letters, uppercase alphabets, digits, any of the
246  * following special characters:
247  *     $ % ' ` - @ { } ~ ! # ( ) & _ ^
248  * In this case Longfilename is not stored in disk.
249  *
250  * WinNT's Extension:
251  * File name and extension name is contain uppercase/lowercase
252  * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT.
253  *
254  * 2) File name is 8.3 format, but it contain the uppercase and
255  * lowercase char, muliti bytes char, etc. In this case numtail is not
256  * added, but Longfilename is stored.
257  *
258  * 3) When the one except for the above, or the following special
259  * character are contained:
260  *        .   [ ] ; , + =
261  * numtail is added, and Longfilename must be stored in disk .
262  */
263 struct shortname_info {
264         unsigned char lower:1,
265                       upper:1,
266                       valid:1;
267 };
268 #define INIT_SHORTNAME_INFO(x)  do {            \
269         (x)->lower = 1;                         \
270         (x)->upper = 1;                         \
271         (x)->valid = 1;                         \
272 } while (0)
273 
274 static inline int to_shortname_char(struct nls_table *nls,
275                                     unsigned char *buf, int buf_size,
276                                     wchar_t *src, struct shortname_info *info)
277 {
278         int len;
279 
280         if (vfat_skip_char(*src)) {
281                 info->valid = 0;
282                 return 0;
283         }
284         if (vfat_replace_char(*src)) {
285                 info->valid = 0;
286                 buf[0] = '_';
287                 return 1;
288         }
289 
290         len = nls->uni2char(*src, buf, buf_size);
291         if (len <= 0) {
292                 info->valid = 0;
293                 buf[0] = '_';
294                 len = 1;
295         } else if (len == 1) {
296                 unsigned char prev = buf[0];
297 
298                 if (buf[0] >= 0x7F) {
299                         info->lower = 0;
300                         info->upper = 0;
301                 }
302 
303                 buf[0] = nls_toupper(nls, buf[0]);
304                 if (isalpha(buf[0])) {
305                         if (buf[0] == prev)
306                                 info->lower = 0;
307                         else
308                                 info->upper = 0;
309                 }
310         } else {
311                 info->lower = 0;
312                 info->upper = 0;
313         }
314 
315         return len;
316 }
317 
318 /*
319  * Given a valid longname, create a unique shortname.  Make sure the
320  * shortname does not exist
321  * Returns negative number on error, 0 for a normal
322  * return, and 1 for valid shortname
323  */
324 static int vfat_create_shortname(struct inode *dir, struct nls_table *nls,
325                                  wchar_t *uname, int ulen,
326                                  unsigned char *name_res, unsigned char *lcase)
327 {
328         struct fat_mount_options *opts = &MSDOS_SB(dir->i_sb)->options;
329         wchar_t *ip, *ext_start, *end, *name_start;
330         unsigned char base[9], ext[4], buf[5], *p;
331         unsigned char charbuf[NLS_MAX_CHARSET_SIZE];
332         int chl, chi;
333         int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen;
334         int is_shortname;
335         struct shortname_info base_info, ext_info;
336 
337         is_shortname = 1;
338         INIT_SHORTNAME_INFO(&base_info);
339         INIT_SHORTNAME_INFO(&ext_info);
340 
341         /* Now, we need to create a shortname from the long name */
342         ext_start = end = &uname[ulen];
343         while (--ext_start >= uname) {
344                 if (*ext_start == 0x002E) {     /* is `.' */
345                         if (ext_start == end - 1) {
346                                 sz = ulen;
347                                 ext_start = NULL;
348                         }
349                         break;
350                 }
351         }
352 
353         if (ext_start == uname - 1) {
354                 sz = ulen;
355                 ext_start = NULL;
356         } else if (ext_start) {
357                 /*
358                  * Names which start with a dot could be just
359                  * an extension eg. "...test".  In this case Win95
360                  * uses the extension as the name and sets no extension.
361                  */
362                 name_start = &uname[0];
363                 while (name_start < ext_start) {
364                         if (!vfat_skip_char(*name_start))
365                                 break;
366                         name_start++;
367                 }
368                 if (name_start != ext_start) {
369                         sz = ext_start - uname;
370                         ext_start++;
371                 } else {
372                         sz = ulen;
373                         ext_start = NULL;
374                 }
375         }
376 
377         numtail_baselen = 6;
378         numtail2_baselen = 2;
379         for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) {
380                 chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
381                                         ip, &base_info);
382                 if (chl == 0)
383                         continue;
384 
385                 if (baselen < 2 && (baselen + chl) > 2)
386                         numtail2_baselen = baselen;
387                 if (baselen < 6 && (baselen + chl) > 6)
388                         numtail_baselen = baselen;
389                 for (chi = 0; chi < chl; chi++) {
390                         *p++ = charbuf[chi];
391                         baselen++;
392                         if (baselen >= 8)
393                                 break;
394                 }
395                 if (baselen >= 8) {
396                         if ((chi < chl - 1) || (ip + 1) - uname < sz)
397                                 is_shortname = 0;
398                         break;
399                 }
400         }
401         if (baselen == 0) {
402                 return -EINVAL;
403         }
404 
405         extlen = 0;
406         if (ext_start) {
407                 for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) {
408                         chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
409                                                 ip, &ext_info);
410                         if (chl == 0)
411                                 continue;
412 
413                         if ((extlen + chl) > 3) {
414                                 is_shortname = 0;
415                                 break;
416                         }
417                         for (chi = 0; chi < chl; chi++) {
418                                 *p++ = charbuf[chi];
419                                 extlen++;
420                         }
421                         if (extlen >= 3) {
422                                 if (ip + 1 != end)
423                                         is_shortname = 0;
424                                 break;
425                         }
426                 }
427         }
428         ext[extlen] = '\0';
429         base[baselen] = '\0';
430 
431         /* Yes, it can happen. ".\xe5" would do it. */
432         if (base[0] == DELETED_FLAG)
433                 base[0] = 0x05;
434 
435         /* OK, at this point we know that base is not longer than 8 symbols,
436          * ext is not longer than 3, base is nonempty, both don't contain
437          * any bad symbols (lowercase transformed to uppercase).
438          */
439 
440         memset(name_res, ' ', MSDOS_NAME);
441         memcpy(name_res, base, baselen);
442         memcpy(name_res + 8, ext, extlen);
443         *lcase = 0;
444         if (is_shortname && base_info.valid && ext_info.valid) {
445                 if (vfat_find_form(dir, name_res) == 0)
446                         return -EEXIST;
447 
448                 if (opts->shortname & VFAT_SFN_CREATE_WIN95) {
449                         return (base_info.upper && ext_info.upper);
450                 } else if (opts->shortname & VFAT_SFN_CREATE_WINNT) {
451                         if ((base_info.upper || base_info.lower) &&
452                             (ext_info.upper || ext_info.lower)) {
453                                 if (!base_info.upper && base_info.lower)
454                                         *lcase |= CASE_LOWER_BASE;
455                                 if (!ext_info.upper && ext_info.lower)
456                                         *lcase |= CASE_LOWER_EXT;
457                                 return 1;
458                         }
459                         return 0;
460                 } else {
461                         BUG();
462                 }
463         }
464 
465         if (opts->numtail == 0)
466                 if (vfat_find_form(dir, name_res) < 0)
467                         return 0;
468 
469         /*
470          * Try to find a unique extension.  This used to
471          * iterate through all possibilities sequentially,
472          * but that gave extremely bad performance.  Windows
473          * only tries a few cases before using random
474          * values for part of the base.
475          */
476 
477         if (baselen > 6) {
478                 baselen = numtail_baselen;
479                 name_res[7] = ' ';
480         }
481         name_res[baselen] = '~';
482         for (i = 1; i < 10; i++) {
483                 name_res[baselen + 1] = i + '';
484                 if (vfat_find_form(dir, name_res) < 0)
485                         return 0;
486         }
487 
488         i = jiffies;
489         sz = (jiffies >> 16) & 0x7;
490         if (baselen > 2) {
491                 baselen = numtail2_baselen;
492                 name_res[7] = ' ';
493         }
494         name_res[baselen + 4] = '~';
495         name_res[baselen + 5] = '1' + sz;
496         while (1) {
497                 snprintf(buf, sizeof(buf), "%04X", i & 0xffff);
498                 memcpy(&name_res[baselen], buf, 4);
499                 if (vfat_find_form(dir, name_res) < 0)
500                         break;
501                 i -= 11;
502         }
503         return 0;
504 }
505 
506 /* Translate a string, including coded sequences into Unicode */
507 static int
508 xlate_to_uni(const unsigned char *name, int len, unsigned char *outname,
509              int *longlen, int *outlen, int escape, int utf8,
510              struct nls_table *nls)
511 {
512         const unsigned char *ip;
513         unsigned char nc;
514         unsigned char *op;
515         unsigned int ec;
516         int i, k, fill;
517         int charlen;
518 
519         if (utf8) {
520                 *outlen = utf8s_to_utf16s(name, len, UTF16_HOST_ENDIAN,
521                                 (wchar_t *) outname, FAT_LFN_LEN + 2);
522                 if (*outlen < 0)
523                         return *outlen;
524                 else if (*outlen > FAT_LFN_LEN)
525                         return -ENAMETOOLONG;
526 
527                 op = &outname[*outlen * sizeof(wchar_t)];
528         } else {
529                 for (i = 0, ip = name, op = outname, *outlen = 0;
530                          i < len && *outlen < FAT_LFN_LEN;
531                          *outlen += 1) {
532                         if (escape && (*ip == ':')) {
533                                 if (i > len - 5)
534                                         return -EINVAL;
535                                 ec = 0;
536                                 for (k = 1; k < 5; k++) {
537                                         nc = ip[k];
538                                         ec <<= 4;
539                                         if (nc >= '' && nc <= '9') {
540                                                 ec |= nc - '';
541                                                 continue;
542                                         }
543                                         if (nc >= 'a' && nc <= 'f') {
544                                                 ec |= nc - ('a' - 10);
545                                                 continue;
546                                         }
547                                         if (nc >= 'A' && nc <= 'F') {
548                                                 ec |= nc - ('A' - 10);
549                                                 continue;
550                                         }
551                                         return -EINVAL;
552                                 }
553                                 *op++ = ec & 0xFF;
554                                 *op++ = ec >> 8;
555                                 ip += 5;
556                                 i += 5;
557                         } else {
558                                 charlen = nls->char2uni(ip, len - i,
559                                                                         (wchar_t *)op);
560                                 if (charlen < 0)
561                                         return -EINVAL;
562                                 ip += charlen;
563                                 i += charlen;
564                                 op += 2;
565                         }
566                 }
567                 if (i < len)
568                         return -ENAMETOOLONG;
569         }
570 
571         *longlen = *outlen;
572         if (*outlen % 13) {
573                 *op++ = 0;
574                 *op++ = 0;
575                 *outlen += 1;
576                 if (*outlen % 13) {
577                         fill = 13 - (*outlen % 13);
578                         for (i = 0; i < fill; i++) {
579                                 *op++ = 0xff;
580                                 *op++ = 0xff;
581                         }
582                         *outlen += fill;
583                 }
584         }
585 
586         return 0;
587 }
588 
589 static int vfat_build_slots(struct inode *dir, const unsigned char *name,
590                             int len, int is_dir, int cluster,
591                             struct timespec *ts,
592                             struct msdos_dir_slot *slots, int *nr_slots)
593 {
594         struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
595         struct fat_mount_options *opts = &sbi->options;
596         struct msdos_dir_slot *ps;
597         struct msdos_dir_entry *de;
598         unsigned char cksum, lcase;
599         unsigned char msdos_name[MSDOS_NAME];
600         wchar_t *uname;
601         __le16 time, date;
602         u8 time_cs;
603         int err, ulen, usize, i;
604         loff_t offset;
605 
606         *nr_slots = 0;
607 
608         uname = __getname();
609         if (!uname)
610                 return -ENOMEM;
611 
612         err = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize,
613                            opts->unicode_xlate, opts->utf8, sbi->nls_io);
614         if (err)
615                 goto out_free;
616 
617         err = vfat_is_used_badchars(uname, ulen);
618         if (err)
619                 goto out_free;
620 
621         err = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen,
622                                     msdos_name, &lcase);
623         if (err < 0)
624                 goto out_free;
625         else if (err == 1) {
626                 de = (struct msdos_dir_entry *)slots;
627                 err = 0;
628                 goto shortname;
629         }
630 
631         /* build the entry of long file name */
632         cksum = fat_checksum(msdos_name);
633 
634         *nr_slots = usize / 13;
635         for (ps = slots, i = *nr_slots; i > 0; i--, ps++) {
636                 ps->id = i;
637                 ps->attr = ATTR_EXT;
638                 ps->reserved = 0;
639                 ps->alias_checksum = cksum;
640                 ps->start = 0;
641                 offset = (i - 1) * 13;
642                 fatwchar_to16(ps->name0_4, uname + offset, 5);
643                 fatwchar_to16(ps->name5_10, uname + offset + 5, 6);
644                 fatwchar_to16(ps->name11_12, uname + offset + 11, 2);
645         }
646         slots[0].id |= 0x40;
647         de = (struct msdos_dir_entry *)ps;
648 
649 shortname:
650         /* build the entry of 8.3 alias name */
651         (*nr_slots)++;
652         memcpy(de->name, msdos_name, MSDOS_NAME);
653         de->attr = is_dir ? ATTR_DIR : ATTR_ARCH;
654         de->lcase = lcase;
655         fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
656         de->time = de->ctime = time;
657         de->date = de->cdate = de->adate = date;
658         de->ctime_cs = time_cs;
659         fat_set_start(de, cluster);
660         de->size = 0;
661 out_free:
662         __putname(uname);
663         return err;
664 }
665 
666 static int vfat_add_entry(struct inode *dir, const struct qstr *qname,
667                           int is_dir, int cluster, struct timespec *ts,
668                           struct fat_slot_info *sinfo)
669 {
670         struct msdos_dir_slot *slots;
671         unsigned int len;
672         int err, nr_slots;
673 
674         len = vfat_striptail_len(qname);
675         if (len == 0)
676                 return -ENOENT;
677 
678         slots = kmalloc(sizeof(*slots) * MSDOS_SLOTS, GFP_NOFS);
679         if (slots == NULL)
680                 return -ENOMEM;
681 
682         err = vfat_build_slots(dir, qname->name, len, is_dir, cluster, ts,
683                                slots, &nr_slots);
684         if (err)
685                 goto cleanup;
686 
687         err = fat_add_entries(dir, slots, nr_slots, sinfo);
688         if (err)
689                 goto cleanup;
690 
691         /* update timestamp */
692         dir->i_ctime = dir->i_mtime = dir->i_atime = *ts;
693         if (IS_DIRSYNC(dir))
694                 (void)fat_sync_inode(dir);
695         else
696                 mark_inode_dirty(dir);
697 cleanup:
698         kfree(slots);
699         return err;
700 }
701 
702 static int vfat_find(struct inode *dir, const struct qstr *qname,
703                      struct fat_slot_info *sinfo)
704 {
705         unsigned int len = vfat_striptail_len(qname);
706         if (len == 0)
707                 return -ENOENT;
708         return fat_search_long(dir, qname->name, len, sinfo);
709 }
710 
711 /*
712  * (nfsd's) anonymous disconnected dentry?
713  * NOTE: !IS_ROOT() is not anonymous (I.e. d_splice_alias() did the job).
714  */
715 static int vfat_d_anon_disconn(struct dentry *dentry)
716 {
717         return IS_ROOT(dentry) && (dentry->d_flags & DCACHE_DISCONNECTED);
718 }
719 
720 static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry,
721                                   unsigned int flags)
722 {
723         struct super_block *sb = dir->i_sb;
724         struct fat_slot_info sinfo;
725         struct inode *inode;
726         struct dentry *alias;
727         int err;
728 
729         mutex_lock(&MSDOS_SB(sb)->s_lock);
730 
731         err = vfat_find(dir, &dentry->d_name, &sinfo);
732         if (err) {
733                 if (err == -ENOENT) {
734                         inode = NULL;
735                         goto out;
736                 }
737                 goto error;
738         }
739 
740         inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
741         brelse(sinfo.bh);
742         if (IS_ERR(inode)) {
743                 err = PTR_ERR(inode);
744                 goto error;
745         }
746 
747         alias = d_find_alias(inode);
748         /*
749          * Checking "alias->d_parent == dentry->d_parent" to make sure
750          * FS is not corrupted (especially double linked dir).
751          */
752         if (alias && alias->d_parent == dentry->d_parent &&
753             !vfat_d_anon_disconn(alias)) {
754                 /*
755                  * This inode has non anonymous-DCACHE_DISCONNECTED
756                  * dentry. This means, the user did ->lookup() by an
757                  * another name (longname vs 8.3 alias of it) in past.
758                  *
759                  * Switch to new one for reason of locality if possible.
760                  */
761                 BUG_ON(d_unhashed(alias));
762                 if (!S_ISDIR(inode->i_mode))
763                         d_move(alias, dentry);
764                 iput(inode);
765                 mutex_unlock(&MSDOS_SB(sb)->s_lock);
766                 return alias;
767         } else
768                 dput(alias);
769 
770 out:
771         mutex_unlock(&MSDOS_SB(sb)->s_lock);
772         if (!inode)
773                 vfat_d_version_set(dentry, dir->i_version);
774         return d_splice_alias(inode, dentry);
775 error:
776         mutex_unlock(&MSDOS_SB(sb)->s_lock);
777         return ERR_PTR(err);
778 }
779 
780 static int vfat_create(struct inode *dir, struct dentry *dentry, umode_t mode,
781                        bool excl)
782 {
783         struct super_block *sb = dir->i_sb;
784         struct inode *inode;
785         struct fat_slot_info sinfo;
786         struct timespec ts;
787         int err;
788 
789         mutex_lock(&MSDOS_SB(sb)->s_lock);
790 
791         ts = current_time(dir);
792         err = vfat_add_entry(dir, &dentry->d_name, 0, 0, &ts, &sinfo);
793         if (err)
794                 goto out;
795         dir->i_version++;
796 
797         inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
798         brelse(sinfo.bh);
799         if (IS_ERR(inode)) {
800                 err = PTR_ERR(inode);
801                 goto out;
802         }
803         inode->i_version++;
804         inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
805         /* timestamp is already written, so mark_inode_dirty() is unneeded. */
806 
807         d_instantiate(dentry, inode);
808 out:
809         mutex_unlock(&MSDOS_SB(sb)->s_lock);
810         return err;
811 }
812 
813 static int vfat_rmdir(struct inode *dir, struct dentry *dentry)
814 {
815         struct inode *inode = d_inode(dentry);
816         struct super_block *sb = dir->i_sb;
817         struct fat_slot_info sinfo;
818         int err;
819 
820         mutex_lock(&MSDOS_SB(sb)->s_lock);
821 
822         err = fat_dir_empty(inode);
823         if (err)
824                 goto out;
825         err = vfat_find(dir, &dentry->d_name, &sinfo);
826         if (err)
827                 goto out;
828 
829         err = fat_remove_entries(dir, &sinfo);  /* and releases bh */
830         if (err)
831                 goto out;
832         drop_nlink(dir);
833 
834         clear_nlink(inode);
835         inode->i_mtime = inode->i_atime = current_time(inode);
836         fat_detach(inode);
837         vfat_d_version_set(dentry, dir->i_version);
838 out:
839         mutex_unlock(&MSDOS_SB(sb)->s_lock);
840 
841         return err;
842 }
843 
844 static int vfat_unlink(struct inode *dir, struct dentry *dentry)
845 {
846         struct inode *inode = d_inode(dentry);
847         struct super_block *sb = dir->i_sb;
848         struct fat_slot_info sinfo;
849         int err;
850 
851         mutex_lock(&MSDOS_SB(sb)->s_lock);
852 
853         err = vfat_find(dir, &dentry->d_name, &sinfo);
854         if (err)
855                 goto out;
856 
857         err = fat_remove_entries(dir, &sinfo);  /* and releases bh */
858         if (err)
859                 goto out;
860         clear_nlink(inode);
861         inode->i_mtime = inode->i_atime = current_time(inode);
862         fat_detach(inode);
863         vfat_d_version_set(dentry, dir->i_version);
864 out:
865         mutex_unlock(&MSDOS_SB(sb)->s_lock);
866 
867         return err;
868 }
869 
870 static int vfat_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
871 {
872         struct super_block *sb = dir->i_sb;
873         struct inode *inode;
874         struct fat_slot_info sinfo;
875         struct timespec ts;
876         int err, cluster;
877 
878         mutex_lock(&MSDOS_SB(sb)->s_lock);
879 
880         ts = current_time(dir);
881         cluster = fat_alloc_new_dir(dir, &ts);
882         if (cluster < 0) {
883                 err = cluster;
884                 goto out;
885         }
886         err = vfat_add_entry(dir, &dentry->d_name, 1, cluster, &ts, &sinfo);
887         if (err)
888                 goto out_free;
889         dir->i_version++;
890         inc_nlink(dir);
891 
892         inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
893         brelse(sinfo.bh);
894         if (IS_ERR(inode)) {
895                 err = PTR_ERR(inode);
896                 /* the directory was completed, just return a error */
897                 goto out;
898         }
899         inode->i_version++;
900         set_nlink(inode, 2);
901         inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
902         /* timestamp is already written, so mark_inode_dirty() is unneeded. */
903 
904         d_instantiate(dentry, inode);
905 
906         mutex_unlock(&MSDOS_SB(sb)->s_lock);
907         return 0;
908 
909 out_free:
910         fat_free_clusters(dir, cluster);
911 out:
912         mutex_unlock(&MSDOS_SB(sb)->s_lock);
913         return err;
914 }
915 
916 static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,
917                        struct inode *new_dir, struct dentry *new_dentry,
918                        unsigned int flags)
919 {
920         struct buffer_head *dotdot_bh;
921         struct msdos_dir_entry *dotdot_de;
922         struct inode *old_inode, *new_inode;
923         struct fat_slot_info old_sinfo, sinfo;
924         struct timespec ts;
925         loff_t new_i_pos;
926         int err, is_dir, update_dotdot, corrupt = 0;
927         struct super_block *sb = old_dir->i_sb;
928 
929         if (flags & ~RENAME_NOREPLACE)
930                 return -EINVAL;
931 
932         old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
933         old_inode = d_inode(old_dentry);
934         new_inode = d_inode(new_dentry);
935         mutex_lock(&MSDOS_SB(sb)->s_lock);
936         err = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo);
937         if (err)
938                 goto out;
939 
940         is_dir = S_ISDIR(old_inode->i_mode);
941         update_dotdot = (is_dir && old_dir != new_dir);
942         if (update_dotdot) {
943                 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) {
944                         err = -EIO;
945                         goto out;
946                 }
947         }
948 
949         ts = current_time(old_dir);
950         if (new_inode) {
951                 if (is_dir) {
952                         err = fat_dir_empty(new_inode);
953                         if (err)
954                                 goto out;
955                 }
956                 new_i_pos = MSDOS_I(new_inode)->i_pos;
957                 fat_detach(new_inode);
958         } else {
959                 err = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir, 0,
960                                      &ts, &sinfo);
961                 if (err)
962                         goto out;
963                 new_i_pos = sinfo.i_pos;
964         }
965         new_dir->i_version++;
966 
967         fat_detach(old_inode);
968         fat_attach(old_inode, new_i_pos);
969         if (IS_DIRSYNC(new_dir)) {
970                 err = fat_sync_inode(old_inode);
971                 if (err)
972                         goto error_inode;
973         } else
974                 mark_inode_dirty(old_inode);
975 
976         if (update_dotdot) {
977                 fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart);
978                 mark_buffer_dirty_inode(dotdot_bh, old_inode);
979                 if (IS_DIRSYNC(new_dir)) {
980                         err = sync_dirty_buffer(dotdot_bh);
981                         if (err)
982                                 goto error_dotdot;
983                 }
984                 drop_nlink(old_dir);
985                 if (!new_inode)
986                         inc_nlink(new_dir);
987         }
988 
989         err = fat_remove_entries(old_dir, &old_sinfo);  /* and releases bh */
990         old_sinfo.bh = NULL;
991         if (err)
992                 goto error_dotdot;
993         old_dir->i_version++;
994         old_dir->i_ctime = old_dir->i_mtime = ts;
995         if (IS_DIRSYNC(old_dir))
996                 (void)fat_sync_inode(old_dir);
997         else
998                 mark_inode_dirty(old_dir);
999 
1000         if (new_inode) {
1001                 drop_nlink(new_inode);
1002                 if (is_dir)
1003                         drop_nlink(new_inode);
1004                 new_inode->i_ctime = ts;
1005         }
1006 out:
1007         brelse(sinfo.bh);
1008         brelse(dotdot_bh);
1009         brelse(old_sinfo.bh);
1010         mutex_unlock(&MSDOS_SB(sb)->s_lock);
1011 
1012         return err;
1013 
1014 error_dotdot:
1015         /* data cluster is shared, serious corruption */
1016         corrupt = 1;
1017 
1018         if (update_dotdot) {
1019                 fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart);
1020                 mark_buffer_dirty_inode(dotdot_bh, old_inode);
1021                 corrupt |= sync_dirty_buffer(dotdot_bh);
1022         }
1023 error_inode:
1024         fat_detach(old_inode);
1025         fat_attach(old_inode, old_sinfo.i_pos);
1026         if (new_inode) {
1027                 fat_attach(new_inode, new_i_pos);
1028                 if (corrupt)
1029                         corrupt |= fat_sync_inode(new_inode);
1030         } else {
1031                 /*
1032                  * If new entry was not sharing the data cluster, it
1033                  * shouldn't be serious corruption.
1034                  */
1035                 int err2 = fat_remove_entries(new_dir, &sinfo);
1036                 if (corrupt)
1037                         corrupt |= err2;
1038                 sinfo.bh = NULL;
1039         }
1040         if (corrupt < 0) {
1041                 fat_fs_error(new_dir->i_sb,
1042                              "%s: Filesystem corrupted (i_pos %lld)",
1043                              __func__, sinfo.i_pos);
1044         }
1045         goto out;
1046 }
1047 
1048 static const struct inode_operations vfat_dir_inode_operations = {
1049         .create         = vfat_create,
1050         .lookup         = vfat_lookup,
1051         .unlink         = vfat_unlink,
1052         .mkdir          = vfat_mkdir,
1053         .rmdir          = vfat_rmdir,
1054         .rename         = vfat_rename,
1055         .setattr        = fat_setattr,
1056         .getattr        = fat_getattr,
1057 };
1058 
1059 static void setup(struct super_block *sb)
1060 {
1061         MSDOS_SB(sb)->dir_ops = &vfat_dir_inode_operations;
1062         if (MSDOS_SB(sb)->options.name_check != 's')
1063                 sb->s_d_op = &vfat_ci_dentry_ops;
1064         else
1065                 sb->s_d_op = &vfat_dentry_ops;
1066 }
1067 
1068 static int vfat_fill_super(struct super_block *sb, void *data, int silent)
1069 {
1070         return fat_fill_super(sb, data, silent, 1, setup);
1071 }
1072 
1073 static struct dentry *vfat_mount(struct file_system_type *fs_type,
1074                        int flags, const char *dev_name,
1075                        void *data)
1076 {
1077         return mount_bdev(fs_type, flags, dev_name, data, vfat_fill_super);
1078 }
1079 
1080 static struct file_system_type vfat_fs_type = {
1081         .owner          = THIS_MODULE,
1082         .name           = "vfat",
1083         .mount          = vfat_mount,
1084         .kill_sb        = kill_block_super,
1085         .fs_flags       = FS_REQUIRES_DEV,
1086 };
1087 MODULE_ALIAS_FS("vfat");
1088 
1089 static int __init init_vfat_fs(void)
1090 {
1091         return register_filesystem(&vfat_fs_type);
1092 }
1093 
1094 static void __exit exit_vfat_fs(void)
1095 {
1096         unregister_filesystem(&vfat_fs_type);
1097 }
1098 
1099 MODULE_LICENSE("GPL");
1100 MODULE_DESCRIPTION("VFAT filesystem support");
1101 MODULE_AUTHOR("Gordon Chaffee");
1102 
1103 module_init(init_vfat_fs)
1104 module_exit(exit_vfat_fs)
1105 

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