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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * linux/fs/vfat/namei.c4 *5 * Written 1992,1993 by Werner Almesberger6 *7 * Windows95/Windows NT compatible extended MSDOS filesystem8 * by Gordon Chaffee Copyright (C) 1995. Send bug reports for the9 * VFAT filesystem to <chaffee@cs.berkeley.edu>. Specify10 * what file operation caused you trouble and if you can duplicate11 * the problem, send a script that demonstrates it.12 *13 * Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>14 *15 * Support Multibyte characters and cleanup by16 * OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>17 */18 19#include <linux/module.h>20#include <linux/ctype.h>21#include <linux/slab.h>22#include <linux/namei.h>23#include <linux/kernel.h>24#include <linux/iversion.h>25#include "fat.h"26 27static inline unsigned long vfat_d_version(struct dentry *dentry)28{29 return (unsigned long) dentry->d_fsdata;30}31 32static inline void vfat_d_version_set(struct dentry *dentry,33 unsigned long version)34{35 dentry->d_fsdata = (void *) version;36}37 38/*39 * If new entry was created in the parent, it could create the 8.340 * alias (the shortname of logname). So, the parent may have the41 * negative-dentry which matches the created 8.3 alias.42 *43 * If it happened, the negative dentry isn't actually negative44 * anymore. So, drop it.45 */46static int vfat_revalidate_shortname(struct dentry *dentry)47{48 int ret = 1;49 spin_lock(&dentry->d_lock);50 if (!inode_eq_iversion(d_inode(dentry->d_parent), vfat_d_version(dentry)))51 ret = 0;52 spin_unlock(&dentry->d_lock);53 return ret;54}55 56static int vfat_revalidate(struct dentry *dentry, unsigned int flags)57{58 if (flags & LOOKUP_RCU)59 return -ECHILD;60 61 /* This is not negative dentry. Always valid. */62 if (d_really_is_positive(dentry))63 return 1;64 return vfat_revalidate_shortname(dentry);65}66 67static int vfat_revalidate_ci(struct dentry *dentry, unsigned int flags)68{69 if (flags & LOOKUP_RCU)70 return -ECHILD;71 72 /*73 * This is not negative dentry. Always valid.74 *75 * Note, rename() to existing directory entry will have ->d_inode,76 * and will use existing name which isn't specified name by user.77 *78 * We may be able to drop this positive dentry here. But dropping79 * positive dentry isn't good idea. So it's unsupported like80 * rename("filename", "FILENAME") for now.81 */82 if (d_really_is_positive(dentry))83 return 1;84 85 /*86 * This may be nfsd (or something), anyway, we can't see the87 * intent of this. So, since this can be for creation, drop it.88 */89 if (!flags)90 return 0;91 92 /*93 * Drop the negative dentry, in order to make sure to use the94 * case sensitive name which is specified by user if this is95 * for creation.96 */97 if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))98 return 0;99 100 return vfat_revalidate_shortname(dentry);101}102 103/* returns the length of a struct qstr, ignoring trailing dots */104static unsigned int __vfat_striptail_len(unsigned int len, const char *name)105{106 while (len && name[len - 1] == '.')107 len--;108 return len;109}110 111static unsigned int vfat_striptail_len(const struct qstr *qstr)112{113 return __vfat_striptail_len(qstr->len, qstr->name);114}115 116/*117 * Compute the hash for the vfat name corresponding to the dentry.118 * Note: if the name is invalid, we leave the hash code unchanged so119 * that the existing dentry can be used. The vfat fs routines will120 * return ENOENT or EINVAL as appropriate.121 */122static int vfat_hash(const struct dentry *dentry, struct qstr *qstr)123{124 qstr->hash = full_name_hash(dentry, qstr->name, vfat_striptail_len(qstr));125 return 0;126}127 128/*129 * Compute the hash for the vfat name corresponding to the dentry.130 * Note: if the name is invalid, we leave the hash code unchanged so131 * that the existing dentry can be used. The vfat fs routines will132 * return ENOENT or EINVAL as appropriate.133 */134static int vfat_hashi(const struct dentry *dentry, struct qstr *qstr)135{136 struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io;137 const unsigned char *name;138 unsigned int len;139 unsigned long hash;140 141 name = qstr->name;142 len = vfat_striptail_len(qstr);143 144 hash = init_name_hash(dentry);145 while (len--)146 hash = partial_name_hash(nls_tolower(t, *name++), hash);147 qstr->hash = end_name_hash(hash);148 149 return 0;150}151 152/*153 * Case insensitive compare of two vfat names.154 */155static int vfat_cmpi(const struct dentry *dentry,156 unsigned int len, const char *str, const struct qstr *name)157{158 struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io;159 unsigned int alen, blen;160 161 /* A filename cannot end in '.' or we treat it like it has none */162 alen = vfat_striptail_len(name);163 blen = __vfat_striptail_len(len, str);164 if (alen == blen) {165 if (nls_strnicmp(t, name->name, str, alen) == 0)166 return 0;167 }168 return 1;169}170 171/*172 * Case sensitive compare of two vfat names.173 */174static int vfat_cmp(const struct dentry *dentry,175 unsigned int len, const char *str, const struct qstr *name)176{177 unsigned int alen, blen;178 179 /* A filename cannot end in '.' or we treat it like it has none */180 alen = vfat_striptail_len(name);181 blen = __vfat_striptail_len(len, str);182 if (alen == blen) {183 if (strncmp(name->name, str, alen) == 0)184 return 0;185 }186 return 1;187}188 189static const struct dentry_operations vfat_ci_dentry_ops = {190 .d_revalidate = vfat_revalidate_ci,191 .d_hash = vfat_hashi,192 .d_compare = vfat_cmpi,193};194 195static const struct dentry_operations vfat_dentry_ops = {196 .d_revalidate = vfat_revalidate,197 .d_hash = vfat_hash,198 .d_compare = vfat_cmp,199};200 201/* Characters that are undesirable in an MS-DOS file name */202 203static inline bool vfat_bad_char(wchar_t w)204{205 return (w < 0x0020)206 || (w == '*') || (w == '?') || (w == '<') || (w == '>')207 || (w == '|') || (w == '"') || (w == ':') || (w == '/')208 || (w == '\\');209}210 211static inline bool vfat_replace_char(wchar_t w)212{213 return (w == '[') || (w == ']') || (w == ';') || (w == ',')214 || (w == '+') || (w == '=');215}216 217static wchar_t vfat_skip_char(wchar_t w)218{219 return (w == '.') || (w == ' ');220}221 222static inline int vfat_is_used_badchars(const wchar_t *s, int len)223{224 int i;225 226 for (i = 0; i < len; i++)227 if (vfat_bad_char(s[i]))228 return -EINVAL;229 230 if (s[i - 1] == ' ') /* last character cannot be space */231 return -EINVAL;232 233 return 0;234}235 236static int vfat_find_form(struct inode *dir, unsigned char *name)237{238 struct fat_slot_info sinfo;239 int err = fat_scan(dir, name, &sinfo);240 if (err)241 return -ENOENT;242 brelse(sinfo.bh);243 return 0;244}245 246/*247 * 1) Valid characters for the 8.3 format alias are any combination of248 * letters, uppercase alphabets, digits, any of the249 * following special characters:250 * $ % ' ` - @ { } ~ ! # ( ) & _ ^251 * In this case Longfilename is not stored in disk.252 *253 * WinNT's Extension:254 * File name and extension name is contain uppercase/lowercase255 * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT.256 *257 * 2) File name is 8.3 format, but it contain the uppercase and258 * lowercase char, muliti bytes char, etc. In this case numtail is not259 * added, but Longfilename is stored.260 *261 * 3) When the one except for the above, or the following special262 * character are contained:263 * . [ ] ; , + =264 * numtail is added, and Longfilename must be stored in disk .265 */266struct shortname_info {267 unsigned char lower:1,268 upper:1,269 valid:1;270};271#define INIT_SHORTNAME_INFO(x) do { \272 (x)->lower = 1; \273 (x)->upper = 1; \274 (x)->valid = 1; \275} while (0)276 277static inline int to_shortname_char(struct nls_table *nls,278 unsigned char *buf, int buf_size,279 wchar_t *src, struct shortname_info *info)280{281 int len;282 283 if (vfat_skip_char(*src)) {284 info->valid = 0;285 return 0;286 }287 if (vfat_replace_char(*src)) {288 info->valid = 0;289 buf[0] = '_';290 return 1;291 }292 293 len = nls->uni2char(*src, buf, buf_size);294 if (len <= 0) {295 info->valid = 0;296 buf[0] = '_';297 len = 1;298 } else if (len == 1) {299 unsigned char prev = buf[0];300 301 if (buf[0] >= 0x7F) {302 info->lower = 0;303 info->upper = 0;304 }305 306 buf[0] = nls_toupper(nls, buf[0]);307 if (isalpha(buf[0])) {308 if (buf[0] == prev)309 info->lower = 0;310 else311 info->upper = 0;312 }313 } else {314 info->lower = 0;315 info->upper = 0;316 }317 318 return len;319}320 321/*322 * Given a valid longname, create a unique shortname. Make sure the323 * shortname does not exist324 * Returns negative number on error, 0 for a normal325 * return, and 1 for valid shortname326 */327static int vfat_create_shortname(struct inode *dir, struct nls_table *nls,328 wchar_t *uname, int ulen,329 unsigned char *name_res, unsigned char *lcase)330{331 struct fat_mount_options *opts = &MSDOS_SB(dir->i_sb)->options;332 wchar_t *ip, *ext_start, *end, *name_start;333 unsigned char base[9], ext[4], buf[5], *p;334 unsigned char charbuf[NLS_MAX_CHARSET_SIZE];335 int chl, chi;336 int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen;337 int is_shortname;338 struct shortname_info base_info, ext_info;339 340 is_shortname = 1;341 INIT_SHORTNAME_INFO(&base_info);342 INIT_SHORTNAME_INFO(&ext_info);343 344 /* Now, we need to create a shortname from the long name */345 ext_start = end = &uname[ulen];346 while (--ext_start >= uname) {347 if (*ext_start == 0x002E) { /* is `.' */348 if (ext_start == end - 1) {349 sz = ulen;350 ext_start = NULL;351 }352 break;353 }354 }355 356 if (ext_start == uname - 1) {357 sz = ulen;358 ext_start = NULL;359 } else if (ext_start) {360 /*361 * Names which start with a dot could be just362 * an extension eg. "...test". In this case Win95363 * uses the extension as the name and sets no extension.364 */365 name_start = &uname[0];366 while (name_start < ext_start) {367 if (!vfat_skip_char(*name_start))368 break;369 name_start++;370 }371 if (name_start != ext_start) {372 sz = ext_start - uname;373 ext_start++;374 } else {375 sz = ulen;376 ext_start = NULL;377 }378 }379 380 numtail_baselen = 6;381 numtail2_baselen = 2;382 for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) {383 chl = to_shortname_char(nls, charbuf, sizeof(charbuf),384 ip, &base_info);385 if (chl == 0)386 continue;387 388 if (baselen < 2 && (baselen + chl) > 2)389 numtail2_baselen = baselen;390 if (baselen < 6 && (baselen + chl) > 6)391 numtail_baselen = baselen;392 for (chi = 0; chi < chl; chi++) {393 *p++ = charbuf[chi];394 baselen++;395 if (baselen >= 8)396 break;397 }398 if (baselen >= 8) {399 if ((chi < chl - 1) || (ip + 1) - uname < sz)400 is_shortname = 0;401 break;402 }403 }404 if (baselen == 0) {405 return -EINVAL;406 }407 408 extlen = 0;409 if (ext_start) {410 for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) {411 chl = to_shortname_char(nls, charbuf, sizeof(charbuf),412 ip, &ext_info);413 if (chl == 0)414 continue;415 416 if ((extlen + chl) > 3) {417 is_shortname = 0;418 break;419 }420 for (chi = 0; chi < chl; chi++) {421 *p++ = charbuf[chi];422 extlen++;423 }424 if (extlen >= 3) {425 if (ip + 1 != end)426 is_shortname = 0;427 break;428 }429 }430 }431 ext[extlen] = '\0';432 base[baselen] = '\0';433 434 /* Yes, it can happen. ".\xe5" would do it. */435 if (base[0] == DELETED_FLAG)436 base[0] = 0x05;437 438 /* OK, at this point we know that base is not longer than 8 symbols,439 * ext is not longer than 3, base is nonempty, both don't contain440 * any bad symbols (lowercase transformed to uppercase).441 */442 443 memset(name_res, ' ', MSDOS_NAME);444 memcpy(name_res, base, baselen);445 memcpy(name_res + 8, ext, extlen);446 *lcase = 0;447 if (is_shortname && base_info.valid && ext_info.valid) {448 if (vfat_find_form(dir, name_res) == 0)449 return -EEXIST;450 451 if (opts->shortname & VFAT_SFN_CREATE_WIN95) {452 return (base_info.upper && ext_info.upper);453 } else if (opts->shortname & VFAT_SFN_CREATE_WINNT) {454 if ((base_info.upper || base_info.lower) &&455 (ext_info.upper || ext_info.lower)) {456 if (!base_info.upper && base_info.lower)457 *lcase |= CASE_LOWER_BASE;458 if (!ext_info.upper && ext_info.lower)459 *lcase |= CASE_LOWER_EXT;460 return 1;461 }462 return 0;463 } else {464 BUG();465 }466 }467 468 if (opts->numtail == 0)469 if (vfat_find_form(dir, name_res) < 0)470 return 0;471 472 /*473 * Try to find a unique extension. This used to474 * iterate through all possibilities sequentially,475 * but that gave extremely bad performance. Windows476 * only tries a few cases before using random477 * values for part of the base.478 */479 480 if (baselen > 6) {481 baselen = numtail_baselen;482 name_res[7] = ' ';483 }484 name_res[baselen] = '~';485 for (i = 1; i < 10; i++) {486 name_res[baselen + 1] = i + '0';487 if (vfat_find_form(dir, name_res) < 0)488 return 0;489 }490 491 i = jiffies;492 sz = (jiffies >> 16) & 0x7;493 if (baselen > 2) {494 baselen = numtail2_baselen;495 name_res[7] = ' ';496 }497 name_res[baselen + 4] = '~';498 name_res[baselen + 5] = '1' + sz;499 while (1) {500 snprintf(buf, sizeof(buf), "%04X", i & 0xffff);501 memcpy(&name_res[baselen], buf, 4);502 if (vfat_find_form(dir, name_res) < 0)503 break;504 i -= 11;505 }506 return 0;507}508 509/* Translate a string, including coded sequences into Unicode */510static int511xlate_to_uni(const unsigned char *name, int len, unsigned char *outname,512 int *longlen, int *outlen, int escape, int utf8,513 struct nls_table *nls)514{515 const unsigned char *ip;516 unsigned char *op;517 int i, fill;518 int charlen;519 520 if (utf8) {521 *outlen = utf8s_to_utf16s(name, len, UTF16_HOST_ENDIAN,522 (wchar_t *) outname, FAT_LFN_LEN + 2);523 if (*outlen < 0)524 return *outlen;525 else if (*outlen > FAT_LFN_LEN)526 return -ENAMETOOLONG;527 528 op = &outname[*outlen * sizeof(wchar_t)];529 } else {530 for (i = 0, ip = name, op = outname, *outlen = 0;531 i < len && *outlen < FAT_LFN_LEN;532 *outlen += 1) {533 if (escape && (*ip == ':')) {534 u8 uc[2];535 536 if (i > len - 5)537 return -EINVAL;538 539 if (hex2bin(uc, ip + 1, 2) < 0)540 return -EINVAL;541 542 *(wchar_t *)op = uc[0] << 8 | uc[1];543 544 op += 2;545 ip += 5;546 i += 5;547 } else {548 charlen = nls->char2uni(ip, len - i,549 (wchar_t *)op);550 if (charlen < 0)551 return -EINVAL;552 ip += charlen;553 i += charlen;554 op += 2;555 }556 }557 if (i < len)558 return -ENAMETOOLONG;559 }560 561 *longlen = *outlen;562 if (*outlen % 13) {563 *op++ = 0;564 *op++ = 0;565 *outlen += 1;566 if (*outlen % 13) {567 fill = 13 - (*outlen % 13);568 for (i = 0; i < fill; i++) {569 *op++ = 0xff;570 *op++ = 0xff;571 }572 *outlen += fill;573 }574 }575 576 return 0;577}578 579static int vfat_build_slots(struct inode *dir, const unsigned char *name,580 int len, int is_dir, int cluster,581 struct timespec64 *ts,582 struct msdos_dir_slot *slots, int *nr_slots)583{584 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);585 struct fat_mount_options *opts = &sbi->options;586 struct msdos_dir_slot *ps;587 struct msdos_dir_entry *de;588 unsigned char cksum, lcase;589 unsigned char msdos_name[MSDOS_NAME];590 wchar_t *uname;591 __le16 time, date;592 u8 time_cs;593 int err, ulen, usize, i;594 loff_t offset;595 596 *nr_slots = 0;597 598 uname = __getname();599 if (!uname)600 return -ENOMEM;601 602 err = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize,603 opts->unicode_xlate, opts->utf8, sbi->nls_io);604 if (err)605 goto out_free;606 607 err = vfat_is_used_badchars(uname, ulen);608 if (err)609 goto out_free;610 611 err = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen,612 msdos_name, &lcase);613 if (err < 0)614 goto out_free;615 else if (err == 1) {616 de = (struct msdos_dir_entry *)slots;617 err = 0;618 goto shortname;619 }620 621 /* build the entry of long file name */622 cksum = fat_checksum(msdos_name);623 624 *nr_slots = usize / 13;625 for (ps = slots, i = *nr_slots; i > 0; i--, ps++) {626 ps->id = i;627 ps->attr = ATTR_EXT;628 ps->reserved = 0;629 ps->alias_checksum = cksum;630 ps->start = 0;631 offset = (i - 1) * 13;632 fatwchar_to16(ps->name0_4, uname + offset, 5);633 fatwchar_to16(ps->name5_10, uname + offset + 5, 6);634 fatwchar_to16(ps->name11_12, uname + offset + 11, 2);635 }636 slots[0].id |= 0x40;637 de = (struct msdos_dir_entry *)ps;638 639shortname:640 /* build the entry of 8.3 alias name */641 (*nr_slots)++;642 memcpy(de->name, msdos_name, MSDOS_NAME);643 de->attr = is_dir ? ATTR_DIR : ATTR_ARCH;644 de->lcase = lcase;645 fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);646 de->time = de->ctime = time;647 de->date = de->cdate = de->adate = date;648 de->ctime_cs = time_cs;649 fat_set_start(de, cluster);650 de->size = 0;651out_free:652 __putname(uname);653 return err;654}655 656static int vfat_add_entry(struct inode *dir, const struct qstr *qname,657 int is_dir, int cluster, struct timespec64 *ts,658 struct fat_slot_info *sinfo)659{660 struct msdos_dir_slot *slots;661 unsigned int len;662 int err, nr_slots;663 664 len = vfat_striptail_len(qname);665 if (len == 0)666 return -ENOENT;667 668 slots = kmalloc_array(MSDOS_SLOTS, sizeof(*slots), GFP_NOFS);669 if (slots == NULL)670 return -ENOMEM;671 672 err = vfat_build_slots(dir, qname->name, len, is_dir, cluster, ts,673 slots, &nr_slots);674 if (err)675 goto cleanup;676 677 err = fat_add_entries(dir, slots, nr_slots, sinfo);678 if (err)679 goto cleanup;680 681 /* update timestamp */682 fat_truncate_time(dir, ts, S_CTIME|S_MTIME);683 if (IS_DIRSYNC(dir))684 (void)fat_sync_inode(dir);685 else686 mark_inode_dirty(dir);687cleanup:688 kfree(slots);689 return err;690}691 692static int vfat_find(struct inode *dir, const struct qstr *qname,693 struct fat_slot_info *sinfo)694{695 unsigned int len = vfat_striptail_len(qname);696 if (len == 0)697 return -ENOENT;698 return fat_search_long(dir, qname->name, len, sinfo);699}700 701static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry,702 unsigned int flags)703{704 struct super_block *sb = dir->i_sb;705 struct fat_slot_info sinfo;706 struct inode *inode;707 struct dentry *alias;708 int err;709 710 mutex_lock(&MSDOS_SB(sb)->s_lock);711 712 err = vfat_find(dir, &dentry->d_name, &sinfo);713 if (err) {714 if (err == -ENOENT) {715 inode = NULL;716 goto out;717 }718 goto error;719 }720 721 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);722 brelse(sinfo.bh);723 if (IS_ERR(inode)) {724 err = PTR_ERR(inode);725 goto error;726 }727 728 alias = d_find_alias(inode);729 /*730 * Checking "alias->d_parent == dentry->d_parent" to make sure731 * FS is not corrupted (especially double linked dir).732 */733 if (alias && alias->d_parent == dentry->d_parent) {734 /*735 * This inode has non anonymous-DCACHE_DISCONNECTED736 * dentry. This means, the user did ->lookup() by an737 * another name (longname vs 8.3 alias of it) in past.738 *739 * Switch to new one for reason of locality if possible.740 */741 if (!S_ISDIR(inode->i_mode))742 d_move(alias, dentry);743 iput(inode);744 mutex_unlock(&MSDOS_SB(sb)->s_lock);745 return alias;746 } else747 dput(alias);748 749out:750 mutex_unlock(&MSDOS_SB(sb)->s_lock);751 if (!inode)752 vfat_d_version_set(dentry, inode_query_iversion(dir));753 return d_splice_alias(inode, dentry);754error:755 mutex_unlock(&MSDOS_SB(sb)->s_lock);756 return ERR_PTR(err);757}758 759static int vfat_create(struct mnt_idmap *idmap, struct inode *dir,760 struct dentry *dentry, umode_t mode, bool excl)761{762 struct super_block *sb = dir->i_sb;763 struct inode *inode;764 struct fat_slot_info sinfo;765 struct timespec64 ts;766 int err;767 768 mutex_lock(&MSDOS_SB(sb)->s_lock);769 770 ts = current_time(dir);771 err = vfat_add_entry(dir, &dentry->d_name, 0, 0, &ts, &sinfo);772 if (err)773 goto out;774 inode_inc_iversion(dir);775 776 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);777 brelse(sinfo.bh);778 if (IS_ERR(inode)) {779 err = PTR_ERR(inode);780 goto out;781 }782 inode_inc_iversion(inode);783 784 d_instantiate(dentry, inode);785out:786 mutex_unlock(&MSDOS_SB(sb)->s_lock);787 return err;788}789 790static int vfat_rmdir(struct inode *dir, struct dentry *dentry)791{792 struct inode *inode = d_inode(dentry);793 struct super_block *sb = dir->i_sb;794 struct fat_slot_info sinfo;795 int err;796 797 mutex_lock(&MSDOS_SB(sb)->s_lock);798 799 err = fat_dir_empty(inode);800 if (err)801 goto out;802 err = vfat_find(dir, &dentry->d_name, &sinfo);803 if (err)804 goto out;805 806 err = fat_remove_entries(dir, &sinfo); /* and releases bh */807 if (err)808 goto out;809 drop_nlink(dir);810 811 clear_nlink(inode);812 fat_truncate_time(inode, NULL, S_ATIME|S_MTIME);813 fat_detach(inode);814 vfat_d_version_set(dentry, inode_query_iversion(dir));815out:816 mutex_unlock(&MSDOS_SB(sb)->s_lock);817 818 return err;819}820 821static int vfat_unlink(struct inode *dir, struct dentry *dentry)822{823 struct inode *inode = d_inode(dentry);824 struct super_block *sb = dir->i_sb;825 struct fat_slot_info sinfo;826 int err;827 828 mutex_lock(&MSDOS_SB(sb)->s_lock);829 830 err = vfat_find(dir, &dentry->d_name, &sinfo);831 if (err)832 goto out;833 834 err = fat_remove_entries(dir, &sinfo); /* and releases bh */835 if (err)836 goto out;837 clear_nlink(inode);838 fat_truncate_time(inode, NULL, S_ATIME|S_MTIME);839 fat_detach(inode);840 vfat_d_version_set(dentry, inode_query_iversion(dir));841out:842 mutex_unlock(&MSDOS_SB(sb)->s_lock);843 844 return err;845}846 847static int vfat_mkdir(struct mnt_idmap *idmap, struct inode *dir,848 struct dentry *dentry, umode_t mode)849{850 struct super_block *sb = dir->i_sb;851 struct inode *inode;852 struct fat_slot_info sinfo;853 struct timespec64 ts;854 int err, cluster;855 856 mutex_lock(&MSDOS_SB(sb)->s_lock);857 858 ts = current_time(dir);859 cluster = fat_alloc_new_dir(dir, &ts);860 if (cluster < 0) {861 err = cluster;862 goto out;863 }864 err = vfat_add_entry(dir, &dentry->d_name, 1, cluster, &ts, &sinfo);865 if (err)866 goto out_free;867 inode_inc_iversion(dir);868 inc_nlink(dir);869 870 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);871 brelse(sinfo.bh);872 if (IS_ERR(inode)) {873 err = PTR_ERR(inode);874 /* the directory was completed, just return a error */875 goto out;876 }877 inode_inc_iversion(inode);878 set_nlink(inode, 2);879 880 d_instantiate(dentry, inode);881 882 mutex_unlock(&MSDOS_SB(sb)->s_lock);883 return 0;884 885out_free:886 fat_free_clusters(dir, cluster);887out:888 mutex_unlock(&MSDOS_SB(sb)->s_lock);889 return err;890}891 892static int vfat_get_dotdot_de(struct inode *inode, struct buffer_head **bh,893 struct msdos_dir_entry **de)894{895 if (S_ISDIR(inode->i_mode)) {896 if (fat_get_dotdot_entry(inode, bh, de))897 return -EIO;898 }899 return 0;900}901 902static int vfat_sync_ipos(struct inode *dir, struct inode *inode)903{904 if (IS_DIRSYNC(dir))905 return fat_sync_inode(inode);906 mark_inode_dirty(inode);907 return 0;908}909 910static int vfat_update_dotdot_de(struct inode *dir, struct inode *inode,911 struct buffer_head *dotdot_bh,912 struct msdos_dir_entry *dotdot_de)913{914 fat_set_start(dotdot_de, MSDOS_I(dir)->i_logstart);915 mark_buffer_dirty_inode(dotdot_bh, inode);916 if (IS_DIRSYNC(dir))917 return sync_dirty_buffer(dotdot_bh);918 return 0;919}920 921static void vfat_update_dir_metadata(struct inode *dir, struct timespec64 *ts)922{923 inode_inc_iversion(dir);924 fat_truncate_time(dir, ts, S_CTIME | S_MTIME);925 if (IS_DIRSYNC(dir))926 (void)fat_sync_inode(dir);927 else928 mark_inode_dirty(dir);929}930 931static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,932 struct inode *new_dir, struct dentry *new_dentry)933{934 struct buffer_head *dotdot_bh;935 struct msdos_dir_entry *dotdot_de = NULL;936 struct inode *old_inode, *new_inode;937 struct fat_slot_info old_sinfo, sinfo;938 struct timespec64 ts;939 loff_t new_i_pos;940 int err, is_dir, corrupt = 0;941 struct super_block *sb = old_dir->i_sb;942 943 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;944 old_inode = d_inode(old_dentry);945 new_inode = d_inode(new_dentry);946 mutex_lock(&MSDOS_SB(sb)->s_lock);947 err = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo);948 if (err)949 goto out;950 951 if (old_dir != new_dir) {952 err = vfat_get_dotdot_de(old_inode, &dotdot_bh, &dotdot_de);953 if (err)954 goto out;955 }956 957 is_dir = S_ISDIR(old_inode->i_mode);958 ts = current_time(old_dir);959 if (new_inode) {960 if (is_dir) {961 err = fat_dir_empty(new_inode);962 if (err)963 goto out;964 }965 new_i_pos = MSDOS_I(new_inode)->i_pos;966 fat_detach(new_inode);967 } else {968 err = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir, 0,969 &ts, &sinfo);970 if (err)971 goto out;972 new_i_pos = sinfo.i_pos;973 }974 inode_inc_iversion(new_dir);975 976 fat_detach(old_inode);977 fat_attach(old_inode, new_i_pos);978 err = vfat_sync_ipos(new_dir, old_inode);979 if (err)980 goto error_inode;981 982 if (dotdot_de) {983 err = vfat_update_dotdot_de(new_dir, old_inode, dotdot_bh,984 dotdot_de);985 if (err)986 goto error_dotdot;987 drop_nlink(old_dir);988 if (!new_inode)989 inc_nlink(new_dir);990 }991 992 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */993 old_sinfo.bh = NULL;994 if (err)995 goto error_dotdot;996 vfat_update_dir_metadata(old_dir, &ts);997 998 if (new_inode) {999 drop_nlink(new_inode);1000 if (is_dir)1001 drop_nlink(new_inode);1002 fat_truncate_time(new_inode, &ts, S_CTIME);1003 }1004out:1005 brelse(sinfo.bh);1006 brelse(dotdot_bh);1007 brelse(old_sinfo.bh);1008 mutex_unlock(&MSDOS_SB(sb)->s_lock);1009 1010 return err;1011 1012error_dotdot:1013 /* data cluster is shared, serious corruption */1014 corrupt = 1;1015 1016 if (dotdot_de) {1017 corrupt |= vfat_update_dotdot_de(old_dir, old_inode, dotdot_bh,1018 dotdot_de);1019 }1020error_inode:1021 fat_detach(old_inode);1022 fat_attach(old_inode, old_sinfo.i_pos);1023 if (new_inode) {1024 fat_attach(new_inode, new_i_pos);1025 if (corrupt)1026 corrupt |= fat_sync_inode(new_inode);1027 } else {1028 /*1029 * If new entry was not sharing the data cluster, it1030 * shouldn't be serious corruption.1031 */1032 int err2 = fat_remove_entries(new_dir, &sinfo);1033 if (corrupt)1034 corrupt |= err2;1035 sinfo.bh = NULL;1036 }1037 if (corrupt < 0) {1038 fat_fs_error(new_dir->i_sb,1039 "%s: Filesystem corrupted (i_pos %lld)",1040 __func__, new_i_pos);1041 }1042 goto out;1043}1044 1045static void vfat_exchange_ipos(struct inode *old_inode, struct inode *new_inode,1046 loff_t old_i_pos, loff_t new_i_pos)1047{1048 fat_detach(old_inode);1049 fat_detach(new_inode);1050 fat_attach(old_inode, new_i_pos);1051 fat_attach(new_inode, old_i_pos);1052}1053 1054static void vfat_move_nlink(struct inode *src, struct inode *dst)1055{1056 drop_nlink(src);1057 inc_nlink(dst);1058}1059 1060static int vfat_rename_exchange(struct inode *old_dir, struct dentry *old_dentry,1061 struct inode *new_dir, struct dentry *new_dentry)1062{1063 struct buffer_head *old_dotdot_bh = NULL, *new_dotdot_bh = NULL;1064 struct msdos_dir_entry *old_dotdot_de = NULL, *new_dotdot_de = NULL;1065 struct inode *old_inode, *new_inode;1066 struct timespec64 ts = current_time(old_dir);1067 loff_t old_i_pos, new_i_pos;1068 int err, corrupt = 0;1069 struct super_block *sb = old_dir->i_sb;1070 1071 old_inode = d_inode(old_dentry);1072 new_inode = d_inode(new_dentry);1073 1074 /* Acquire super block lock for the operation to be atomic */1075 mutex_lock(&MSDOS_SB(sb)->s_lock);1076 1077 /* if directories are not the same, get ".." info to update */1078 if (old_dir != new_dir) {1079 err = vfat_get_dotdot_de(old_inode, &old_dotdot_bh,1080 &old_dotdot_de);1081 if (err)1082 goto out;1083 1084 err = vfat_get_dotdot_de(new_inode, &new_dotdot_bh,1085 &new_dotdot_de);1086 if (err)1087 goto out;1088 }1089 1090 old_i_pos = MSDOS_I(old_inode)->i_pos;1091 new_i_pos = MSDOS_I(new_inode)->i_pos;1092 1093 vfat_exchange_ipos(old_inode, new_inode, old_i_pos, new_i_pos);1094 1095 err = vfat_sync_ipos(old_dir, new_inode);1096 if (err)1097 goto error_exchange;1098 err = vfat_sync_ipos(new_dir, old_inode);1099 if (err)1100 goto error_exchange;1101 1102 /* update ".." directory entry info */1103 if (old_dotdot_de) {1104 err = vfat_update_dotdot_de(new_dir, old_inode, old_dotdot_bh,1105 old_dotdot_de);1106 if (err)1107 goto error_old_dotdot;1108 }1109 if (new_dotdot_de) {1110 err = vfat_update_dotdot_de(old_dir, new_inode, new_dotdot_bh,1111 new_dotdot_de);1112 if (err)1113 goto error_new_dotdot;1114 }1115 1116 /* if cross directory and only one is a directory, adjust nlink */1117 if (!old_dotdot_de != !new_dotdot_de) {1118 if (old_dotdot_de)1119 vfat_move_nlink(old_dir, new_dir);1120 else1121 vfat_move_nlink(new_dir, old_dir);1122 }1123 1124 vfat_update_dir_metadata(old_dir, &ts);1125 /* if directories are not the same, update new_dir as well */1126 if (old_dir != new_dir)1127 vfat_update_dir_metadata(new_dir, &ts);1128 1129out:1130 brelse(old_dotdot_bh);1131 brelse(new_dotdot_bh);1132 mutex_unlock(&MSDOS_SB(sb)->s_lock);1133 1134 return err;1135 1136error_new_dotdot:1137 if (new_dotdot_de) {1138 corrupt |= vfat_update_dotdot_de(new_dir, new_inode,1139 new_dotdot_bh, new_dotdot_de);1140 }1141 1142error_old_dotdot:1143 if (old_dotdot_de) {1144 corrupt |= vfat_update_dotdot_de(old_dir, old_inode,1145 old_dotdot_bh, old_dotdot_de);1146 }1147 1148error_exchange:1149 vfat_exchange_ipos(old_inode, new_inode, new_i_pos, old_i_pos);1150 corrupt |= vfat_sync_ipos(new_dir, new_inode);1151 corrupt |= vfat_sync_ipos(old_dir, old_inode);1152 1153 if (corrupt < 0) {1154 fat_fs_error(new_dir->i_sb,1155 "%s: Filesystem corrupted (i_pos %lld, %lld)",1156 __func__, old_i_pos, new_i_pos);1157 }1158 goto out;1159}1160 1161static int vfat_rename2(struct mnt_idmap *idmap, struct inode *old_dir,1162 struct dentry *old_dentry, struct inode *new_dir,1163 struct dentry *new_dentry, unsigned int flags)1164{1165 if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))1166 return -EINVAL;1167 1168 if (flags & RENAME_EXCHANGE) {1169 return vfat_rename_exchange(old_dir, old_dentry,1170 new_dir, new_dentry);1171 }1172 1173 /* VFS already handled RENAME_NOREPLACE, handle it as a normal rename */1174 return vfat_rename(old_dir, old_dentry, new_dir, new_dentry);1175}1176 1177static const struct inode_operations vfat_dir_inode_operations = {1178 .create = vfat_create,1179 .lookup = vfat_lookup,1180 .unlink = vfat_unlink,1181 .mkdir = vfat_mkdir,1182 .rmdir = vfat_rmdir,1183 .rename = vfat_rename2,1184 .setattr = fat_setattr,1185 .getattr = fat_getattr,1186 .update_time = fat_update_time,1187};1188 1189static void setup(struct super_block *sb)1190{1191 MSDOS_SB(sb)->dir_ops = &vfat_dir_inode_operations;1192 if (MSDOS_SB(sb)->options.name_check != 's')1193 sb->s_d_op = &vfat_ci_dentry_ops;1194 else1195 sb->s_d_op = &vfat_dentry_ops;1196}1197 1198static int vfat_fill_super(struct super_block *sb, struct fs_context *fc)1199{1200 return fat_fill_super(sb, fc, setup);1201}1202 1203static int vfat_get_tree(struct fs_context *fc)1204{1205 return get_tree_bdev(fc, vfat_fill_super);1206}1207 1208static int vfat_parse_param(struct fs_context *fc, struct fs_parameter *param)1209{1210 return fat_parse_param(fc, param, true);1211}1212 1213static const struct fs_context_operations vfat_context_ops = {1214 .parse_param = vfat_parse_param,1215 .get_tree = vfat_get_tree,1216 .reconfigure = fat_reconfigure,1217 .free = fat_free_fc,1218};1219 1220static int vfat_init_fs_context(struct fs_context *fc)1221{1222 int err;1223 1224 /* Initialize with is_vfat == true */1225 err = fat_init_fs_context(fc, true);1226 if (err)1227 return err;1228 1229 fc->ops = &vfat_context_ops;1230 return 0;1231}1232 1233static struct file_system_type vfat_fs_type = {1234 .owner = THIS_MODULE,1235 .name = "vfat",1236 .kill_sb = kill_block_super,1237 .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,1238 .init_fs_context = vfat_init_fs_context,1239 .parameters = fat_param_spec,1240};1241MODULE_ALIAS_FS("vfat");1242 1243static int __init init_vfat_fs(void)1244{1245 return register_filesystem(&vfat_fs_type);1246}1247 1248static void __exit exit_vfat_fs(void)1249{1250 unregister_filesystem(&vfat_fs_type);1251}1252 1253MODULE_LICENSE("GPL");1254MODULE_DESCRIPTION("VFAT filesystem support");1255MODULE_AUTHOR("Gordon Chaffee");1256 1257module_init(init_vfat_fs)1258module_exit(exit_vfat_fs)1259