diff options
Diffstat (limited to 'fs/fat/namei_vfat.c')
| -rw-r--r-- | fs/fat/namei_vfat.c | 1234 |
1 files changed, 1234 insertions, 0 deletions
diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c new file mode 100644 index 000000000..21620054e --- /dev/null +++ b/fs/fat/namei_vfat.c @@ -0,0 +1,1234 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * linux/fs/vfat/namei.c + * + * Written 1992,1993 by Werner Almesberger + * + * Windows95/Windows NT compatible extended MSDOS filesystem + * by Gordon Chaffee Copyright (C) 1995. Send bug reports for the + * VFAT filesystem to <chaffee@cs.berkeley.edu>. Specify + * what file operation caused you trouble and if you can duplicate + * the problem, send a script that demonstrates it. + * + * Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de> + * + * Support Multibyte characters and cleanup by + * OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> + */ + +#include <linux/module.h> +#include <linux/ctype.h> +#include <linux/slab.h> +#include <linux/namei.h> +#include <linux/kernel.h> +#include <linux/iversion.h> +#include "fat.h" + +static inline unsigned long vfat_d_version(struct dentry *dentry) +{ + return (unsigned long) dentry->d_fsdata; +} + +static inline void vfat_d_version_set(struct dentry *dentry, + unsigned long version) +{ + dentry->d_fsdata = (void *) version; +} + +/* + * If new entry was created in the parent, it could create the 8.3 + * alias (the shortname of logname). So, the parent may have the + * negative-dentry which matches the created 8.3 alias. + * + * If it happened, the negative dentry isn't actually negative + * anymore. So, drop it. + */ +static int vfat_revalidate_shortname(struct dentry *dentry) +{ + int ret = 1; + spin_lock(&dentry->d_lock); + if (!inode_eq_iversion(d_inode(dentry->d_parent), vfat_d_version(dentry))) + ret = 0; + spin_unlock(&dentry->d_lock); + return ret; +} + +static int vfat_revalidate(struct dentry *dentry, unsigned int flags) +{ + if (flags & LOOKUP_RCU) + return -ECHILD; + + /* This is not negative dentry. Always valid. */ + if (d_really_is_positive(dentry)) + return 1; + return vfat_revalidate_shortname(dentry); +} + +static int vfat_revalidate_ci(struct dentry *dentry, unsigned int flags) +{ + if (flags & LOOKUP_RCU) + return -ECHILD; + + /* + * This is not negative dentry. Always valid. + * + * Note, rename() to existing directory entry will have ->d_inode, + * and will use existing name which isn't specified name by user. + * + * We may be able to drop this positive dentry here. But dropping + * positive dentry isn't good idea. So it's unsupported like + * rename("filename", "FILENAME") for now. + */ + if (d_really_is_positive(dentry)) + return 1; + + /* + * This may be nfsd (or something), anyway, we can't see the + * intent of this. So, since this can be for creation, drop it. + */ + if (!flags) + return 0; + + /* + * Drop the negative dentry, in order to make sure to use the + * case sensitive name which is specified by user if this is + * for creation. + */ + if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET)) + return 0; + + return vfat_revalidate_shortname(dentry); +} + +/* returns the length of a struct qstr, ignoring trailing dots */ +static unsigned int __vfat_striptail_len(unsigned int len, const char *name) +{ + while (len && name[len - 1] == '.') + len--; + return len; +} + +static unsigned int vfat_striptail_len(const struct qstr *qstr) +{ + return __vfat_striptail_len(qstr->len, qstr->name); +} + +/* + * Compute the hash for the vfat name corresponding to the dentry. + * Note: if the name is invalid, we leave the hash code unchanged so + * that the existing dentry can be used. The vfat fs routines will + * return ENOENT or EINVAL as appropriate. + */ +static int vfat_hash(const struct dentry *dentry, struct qstr *qstr) +{ + qstr->hash = full_name_hash(dentry, qstr->name, vfat_striptail_len(qstr)); + return 0; +} + +/* + * Compute the hash for the vfat name corresponding to the dentry. + * Note: if the name is invalid, we leave the hash code unchanged so + * that the existing dentry can be used. The vfat fs routines will + * return ENOENT or EINVAL as appropriate. + */ +static int vfat_hashi(const struct dentry *dentry, struct qstr *qstr) +{ + struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io; + const unsigned char *name; + unsigned int len; + unsigned long hash; + + name = qstr->name; + len = vfat_striptail_len(qstr); + + hash = init_name_hash(dentry); + while (len--) + hash = partial_name_hash(nls_tolower(t, *name++), hash); + qstr->hash = end_name_hash(hash); + + return 0; +} + +/* + * Case insensitive compare of two vfat names. + */ +static int vfat_cmpi(const struct dentry *dentry, + unsigned int len, const char *str, const struct qstr *name) +{ + struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io; + unsigned int alen, blen; + + /* A filename cannot end in '.' or we treat it like it has none */ + alen = vfat_striptail_len(name); + blen = __vfat_striptail_len(len, str); + if (alen == blen) { + if (nls_strnicmp(t, name->name, str, alen) == 0) + return 0; + } + return 1; +} + +/* + * Case sensitive compare of two vfat names. + */ +static int vfat_cmp(const struct dentry *dentry, + unsigned int len, const char *str, const struct qstr *name) +{ + unsigned int alen, blen; + + /* A filename cannot end in '.' or we treat it like it has none */ + alen = vfat_striptail_len(name); + blen = __vfat_striptail_len(len, str); + if (alen == blen) { + if (strncmp(name->name, str, alen) == 0) + return 0; + } + return 1; +} + +static const struct dentry_operations vfat_ci_dentry_ops = { + .d_revalidate = vfat_revalidate_ci, + .d_hash = vfat_hashi, + .d_compare = vfat_cmpi, +}; + +static const struct dentry_operations vfat_dentry_ops = { + .d_revalidate = vfat_revalidate, + .d_hash = vfat_hash, + .d_compare = vfat_cmp, +}; + +/* Characters that are undesirable in an MS-DOS file name */ + +static inline wchar_t vfat_bad_char(wchar_t w) +{ + return (w < 0x0020) + || (w == '*') || (w == '?') || (w == '<') || (w == '>') + || (w == '|') || (w == '"') || (w == ':') || (w == '/') + || (w == '\\'); +} + +static inline wchar_t vfat_replace_char(wchar_t w) +{ + return (w == '[') || (w == ']') || (w == ';') || (w == ',') + || (w == '+') || (w == '='); +} + +static wchar_t vfat_skip_char(wchar_t w) +{ + return (w == '.') || (w == ' '); +} + +static inline int vfat_is_used_badchars(const wchar_t *s, int len) +{ + int i; + + for (i = 0; i < len; i++) + if (vfat_bad_char(s[i])) + return -EINVAL; + + if (s[i - 1] == ' ') /* last character cannot be space */ + return -EINVAL; + + return 0; +} + +static int vfat_find_form(struct inode *dir, unsigned char *name) +{ + struct fat_slot_info sinfo; + int err = fat_scan(dir, name, &sinfo); + if (err) + return -ENOENT; + brelse(sinfo.bh); + return 0; +} + +/* + * 1) Valid characters for the 8.3 format alias are any combination of + * letters, uppercase alphabets, digits, any of the + * following special characters: + * $ % ' ` - @ { } ~ ! # ( ) & _ ^ + * In this case Longfilename is not stored in disk. + * + * WinNT's Extension: + * File name and extension name is contain uppercase/lowercase + * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT. + * + * 2) File name is 8.3 format, but it contain the uppercase and + * lowercase char, muliti bytes char, etc. In this case numtail is not + * added, but Longfilename is stored. + * + * 3) When the one except for the above, or the following special + * character are contained: + * . [ ] ; , + = + * numtail is added, and Longfilename must be stored in disk . + */ +struct shortname_info { + unsigned char lower:1, + upper:1, + valid:1; +}; +#define INIT_SHORTNAME_INFO(x) do { \ + (x)->lower = 1; \ + (x)->upper = 1; \ + (x)->valid = 1; \ +} while (0) + +static inline int to_shortname_char(struct nls_table *nls, + unsigned char *buf, int buf_size, + wchar_t *src, struct shortname_info *info) +{ + int len; + + if (vfat_skip_char(*src)) { + info->valid = 0; + return 0; + } + if (vfat_replace_char(*src)) { + info->valid = 0; + buf[0] = '_'; + return 1; + } + + len = nls->uni2char(*src, buf, buf_size); + if (len <= 0) { + info->valid = 0; + buf[0] = '_'; + len = 1; + } else if (len == 1) { + unsigned char prev = buf[0]; + + if (buf[0] >= 0x7F) { + info->lower = 0; + info->upper = 0; + } + + buf[0] = nls_toupper(nls, buf[0]); + if (isalpha(buf[0])) { + if (buf[0] == prev) + info->lower = 0; + else + info->upper = 0; + } + } else { + info->lower = 0; + info->upper = 0; + } + + return len; +} + +/* + * Given a valid longname, create a unique shortname. Make sure the + * shortname does not exist + * Returns negative number on error, 0 for a normal + * return, and 1 for valid shortname + */ +static int vfat_create_shortname(struct inode *dir, struct nls_table *nls, + wchar_t *uname, int ulen, + unsigned char *name_res, unsigned char *lcase) +{ + struct fat_mount_options *opts = &MSDOS_SB(dir->i_sb)->options; + wchar_t *ip, *ext_start, *end, *name_start; + unsigned char base[9], ext[4], buf[5], *p; + unsigned char charbuf[NLS_MAX_CHARSET_SIZE]; + int chl, chi; + int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen; + int is_shortname; + struct shortname_info base_info, ext_info; + + is_shortname = 1; + INIT_SHORTNAME_INFO(&base_info); + INIT_SHORTNAME_INFO(&ext_info); + + /* Now, we need to create a shortname from the long name */ + ext_start = end = &uname[ulen]; + while (--ext_start >= uname) { + if (*ext_start == 0x002E) { /* is `.' */ + if (ext_start == end - 1) { + sz = ulen; + ext_start = NULL; + } + break; + } + } + + if (ext_start == uname - 1) { + sz = ulen; + ext_start = NULL; + } else if (ext_start) { + /* + * Names which start with a dot could be just + * an extension eg. "...test". In this case Win95 + * uses the extension as the name and sets no extension. + */ + name_start = &uname[0]; + while (name_start < ext_start) { + if (!vfat_skip_char(*name_start)) + break; + name_start++; + } + if (name_start != ext_start) { + sz = ext_start - uname; + ext_start++; + } else { + sz = ulen; + ext_start = NULL; + } + } + + numtail_baselen = 6; + numtail2_baselen = 2; + for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) { + chl = to_shortname_char(nls, charbuf, sizeof(charbuf), + ip, &base_info); + if (chl == 0) + continue; + + if (baselen < 2 && (baselen + chl) > 2) + numtail2_baselen = baselen; + if (baselen < 6 && (baselen + chl) > 6) + numtail_baselen = baselen; + for (chi = 0; chi < chl; chi++) { + *p++ = charbuf[chi]; + baselen++; + if (baselen >= 8) + break; + } + if (baselen >= 8) { + if ((chi < chl - 1) || (ip + 1) - uname < sz) + is_shortname = 0; + break; + } + } + if (baselen == 0) { + return -EINVAL; + } + + extlen = 0; + if (ext_start) { + for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) { + chl = to_shortname_char(nls, charbuf, sizeof(charbuf), + ip, &ext_info); + if (chl == 0) + continue; + + if ((extlen + chl) > 3) { + is_shortname = 0; + break; + } + for (chi = 0; chi < chl; chi++) { + *p++ = charbuf[chi]; + extlen++; + } + if (extlen >= 3) { + if (ip + 1 != end) + is_shortname = 0; + break; + } + } + } + ext[extlen] = '\0'; + base[baselen] = '\0'; + + /* Yes, it can happen. ".\xe5" would do it. */ + if (base[0] == DELETED_FLAG) + base[0] = 0x05; + + /* OK, at this point we know that base is not longer than 8 symbols, + * ext is not longer than 3, base is nonempty, both don't contain + * any bad symbols (lowercase transformed to uppercase). + */ + + memset(name_res, ' ', MSDOS_NAME); + memcpy(name_res, base, baselen); + memcpy(name_res + 8, ext, extlen); + *lcase = 0; + if (is_shortname && base_info.valid && ext_info.valid) { + if (vfat_find_form(dir, name_res) == 0) + return -EEXIST; + + if (opts->shortname & VFAT_SFN_CREATE_WIN95) { + return (base_info.upper && ext_info.upper); + } else if (opts->shortname & VFAT_SFN_CREATE_WINNT) { + if ((base_info.upper || base_info.lower) && + (ext_info.upper || ext_info.lower)) { + if (!base_info.upper && base_info.lower) + *lcase |= CASE_LOWER_BASE; + if (!ext_info.upper && ext_info.lower) + *lcase |= CASE_LOWER_EXT; + return 1; + } + return 0; + } else { + BUG(); + } + } + + if (opts->numtail == 0) + if (vfat_find_form(dir, name_res) < 0) + return 0; + + /* + * Try to find a unique extension. This used to + * iterate through all possibilities sequentially, + * but that gave extremely bad performance. Windows + * only tries a few cases before using random + * values for part of the base. + */ + + if (baselen > 6) { + baselen = numtail_baselen; + name_res[7] = ' '; + } + name_res[baselen] = '~'; + for (i = 1; i < 10; i++) { + name_res[baselen + 1] = i + '0'; + if (vfat_find_form(dir, name_res) < 0) + return 0; + } + + i = jiffies; + sz = (jiffies >> 16) & 0x7; + if (baselen > 2) { + baselen = numtail2_baselen; + name_res[7] = ' '; + } + name_res[baselen + 4] = '~'; + name_res[baselen + 5] = '1' + sz; + while (1) { + snprintf(buf, sizeof(buf), "%04X", i & 0xffff); + memcpy(&name_res[baselen], buf, 4); + if (vfat_find_form(dir, name_res) < 0) + break; + i -= 11; + } + return 0; +} + +/* Translate a string, including coded sequences into Unicode */ +static int +xlate_to_uni(const unsigned char *name, int len, unsigned char *outname, + int *longlen, int *outlen, int escape, int utf8, + struct nls_table *nls) +{ + const unsigned char *ip; + unsigned char *op; + int i, fill; + int charlen; + + if (utf8) { + *outlen = utf8s_to_utf16s(name, len, UTF16_HOST_ENDIAN, + (wchar_t *) outname, FAT_LFN_LEN + 2); + if (*outlen < 0) + return *outlen; + else if (*outlen > FAT_LFN_LEN) + return -ENAMETOOLONG; + + op = &outname[*outlen * sizeof(wchar_t)]; + } else { + for (i = 0, ip = name, op = outname, *outlen = 0; + i < len && *outlen < FAT_LFN_LEN; + *outlen += 1) { + if (escape && (*ip == ':')) { + u8 uc[2]; + + if (i > len - 5) + return -EINVAL; + + if (hex2bin(uc, ip + 1, 2) < 0) + return -EINVAL; + + *(wchar_t *)op = uc[0] << 8 | uc[1]; + + op += 2; + ip += 5; + i += 5; + } else { + charlen = nls->char2uni(ip, len - i, + (wchar_t *)op); + if (charlen < 0) + return -EINVAL; + ip += charlen; + i += charlen; + op += 2; + } + } + if (i < len) + return -ENAMETOOLONG; + } + + *longlen = *outlen; + if (*outlen % 13) { + *op++ = 0; + *op++ = 0; + *outlen += 1; + if (*outlen % 13) { + fill = 13 - (*outlen % 13); + for (i = 0; i < fill; i++) { + *op++ = 0xff; + *op++ = 0xff; + } + *outlen += fill; + } + } + + return 0; +} + +static int vfat_build_slots(struct inode *dir, const unsigned char *name, + int len, int is_dir, int cluster, + struct timespec64 *ts, + struct msdos_dir_slot *slots, int *nr_slots) +{ + struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb); + struct fat_mount_options *opts = &sbi->options; + struct msdos_dir_slot *ps; + struct msdos_dir_entry *de; + unsigned char cksum, lcase; + unsigned char msdos_name[MSDOS_NAME]; + wchar_t *uname; + __le16 time, date; + u8 time_cs; + int err, ulen, usize, i; + loff_t offset; + + *nr_slots = 0; + + uname = __getname(); + if (!uname) + return -ENOMEM; + + err = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize, + opts->unicode_xlate, opts->utf8, sbi->nls_io); + if (err) + goto out_free; + + err = vfat_is_used_badchars(uname, ulen); + if (err) + goto out_free; + + err = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen, + msdos_name, &lcase); + if (err < 0) + goto out_free; + else if (err == 1) { + de = (struct msdos_dir_entry *)slots; + err = 0; + goto shortname; + } + + /* build the entry of long file name */ + cksum = fat_checksum(msdos_name); + + *nr_slots = usize / 13; + for (ps = slots, i = *nr_slots; i > 0; i--, ps++) { + ps->id = i; + ps->attr = ATTR_EXT; + ps->reserved = 0; + ps->alias_checksum = cksum; + ps->start = 0; + offset = (i - 1) * 13; + fatwchar_to16(ps->name0_4, uname + offset, 5); + fatwchar_to16(ps->name5_10, uname + offset + 5, 6); + fatwchar_to16(ps->name11_12, uname + offset + 11, 2); + } + slots[0].id |= 0x40; + de = (struct msdos_dir_entry *)ps; + +shortname: + /* build the entry of 8.3 alias name */ + (*nr_slots)++; + memcpy(de->name, msdos_name, MSDOS_NAME); + de->attr = is_dir ? ATTR_DIR : ATTR_ARCH; + de->lcase = lcase; + fat_time_unix2fat(sbi, ts, &time, &date, &time_cs); + de->time = de->ctime = time; + de->date = de->cdate = de->adate = date; + de->ctime_cs = time_cs; + fat_set_start(de, cluster); + de->size = 0; +out_free: + __putname(uname); + return err; +} + +static int vfat_add_entry(struct inode *dir, const struct qstr *qname, + int is_dir, int cluster, struct timespec64 *ts, + struct fat_slot_info *sinfo) +{ + struct msdos_dir_slot *slots; + unsigned int len; + int err, nr_slots; + + len = vfat_striptail_len(qname); + if (len == 0) + return -ENOENT; + + slots = kmalloc_array(MSDOS_SLOTS, sizeof(*slots), GFP_NOFS); + if (slots == NULL) + return -ENOMEM; + + err = vfat_build_slots(dir, qname->name, len, is_dir, cluster, ts, + slots, &nr_slots); + if (err) + goto cleanup; + + err = fat_add_entries(dir, slots, nr_slots, sinfo); + if (err) + goto cleanup; + + /* update timestamp */ + fat_truncate_time(dir, ts, S_CTIME|S_MTIME); + if (IS_DIRSYNC(dir)) + (void)fat_sync_inode(dir); + else + mark_inode_dirty(dir); +cleanup: + kfree(slots); + return err; +} + +static int vfat_find(struct inode *dir, const struct qstr *qname, + struct fat_slot_info *sinfo) +{ + unsigned int len = vfat_striptail_len(qname); + if (len == 0) + return -ENOENT; + return fat_search_long(dir, qname->name, len, sinfo); +} + +static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry, + unsigned int flags) +{ + struct super_block *sb = dir->i_sb; + struct fat_slot_info sinfo; + struct inode *inode; + struct dentry *alias; + int err; + + mutex_lock(&MSDOS_SB(sb)->s_lock); + + err = vfat_find(dir, &dentry->d_name, &sinfo); + if (err) { + if (err == -ENOENT) { + inode = NULL; + goto out; + } + goto error; + } + + inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); + brelse(sinfo.bh); + if (IS_ERR(inode)) { + err = PTR_ERR(inode); + goto error; + } + + alias = d_find_alias(inode); + /* + * Checking "alias->d_parent == dentry->d_parent" to make sure + * FS is not corrupted (especially double linked dir). + */ + if (alias && alias->d_parent == dentry->d_parent) { + /* + * This inode has non anonymous-DCACHE_DISCONNECTED + * dentry. This means, the user did ->lookup() by an + * another name (longname vs 8.3 alias of it) in past. + * + * Switch to new one for reason of locality if possible. + */ + if (!S_ISDIR(inode->i_mode)) + d_move(alias, dentry); + iput(inode); + mutex_unlock(&MSDOS_SB(sb)->s_lock); + return alias; + } else + dput(alias); + +out: + mutex_unlock(&MSDOS_SB(sb)->s_lock); + if (!inode) + vfat_d_version_set(dentry, inode_query_iversion(dir)); + return d_splice_alias(inode, dentry); +error: + mutex_unlock(&MSDOS_SB(sb)->s_lock); + return ERR_PTR(err); +} + +static int vfat_create(struct user_namespace *mnt_userns, struct inode *dir, + struct dentry *dentry, umode_t mode, bool excl) +{ + struct super_block *sb = dir->i_sb; + struct inode *inode; + struct fat_slot_info sinfo; + struct timespec64 ts; + int err; + + mutex_lock(&MSDOS_SB(sb)->s_lock); + + ts = current_time(dir); + err = vfat_add_entry(dir, &dentry->d_name, 0, 0, &ts, &sinfo); + if (err) + goto out; + inode_inc_iversion(dir); + + inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); + brelse(sinfo.bh); + if (IS_ERR(inode)) { + err = PTR_ERR(inode); + goto out; + } + inode_inc_iversion(inode); + + d_instantiate(dentry, inode); +out: + mutex_unlock(&MSDOS_SB(sb)->s_lock); + return err; +} + +static int vfat_rmdir(struct inode *dir, struct dentry *dentry) +{ + struct inode *inode = d_inode(dentry); + struct super_block *sb = dir->i_sb; + struct fat_slot_info sinfo; + int err; + + mutex_lock(&MSDOS_SB(sb)->s_lock); + + err = fat_dir_empty(inode); + if (err) + goto out; + err = vfat_find(dir, &dentry->d_name, &sinfo); + if (err) + goto out; + + err = fat_remove_entries(dir, &sinfo); /* and releases bh */ + if (err) + goto out; + drop_nlink(dir); + + clear_nlink(inode); + fat_truncate_time(inode, NULL, S_ATIME|S_MTIME); + fat_detach(inode); + vfat_d_version_set(dentry, inode_query_iversion(dir)); +out: + mutex_unlock(&MSDOS_SB(sb)->s_lock); + + return err; +} + +static int vfat_unlink(struct inode *dir, struct dentry *dentry) +{ + struct inode *inode = d_inode(dentry); + struct super_block *sb = dir->i_sb; + struct fat_slot_info sinfo; + int err; + + mutex_lock(&MSDOS_SB(sb)->s_lock); + + err = vfat_find(dir, &dentry->d_name, &sinfo); + if (err) + goto out; + + err = fat_remove_entries(dir, &sinfo); /* and releases bh */ + if (err) + goto out; + clear_nlink(inode); + fat_truncate_time(inode, NULL, S_ATIME|S_MTIME); + fat_detach(inode); + vfat_d_version_set(dentry, inode_query_iversion(dir)); +out: + mutex_unlock(&MSDOS_SB(sb)->s_lock); + + return err; +} + +static int vfat_mkdir(struct user_namespace *mnt_userns, struct inode *dir, + struct dentry *dentry, umode_t mode) +{ + struct super_block *sb = dir->i_sb; + struct inode *inode; + struct fat_slot_info sinfo; + struct timespec64 ts; + int err, cluster; + + mutex_lock(&MSDOS_SB(sb)->s_lock); + + ts = current_time(dir); + cluster = fat_alloc_new_dir(dir, &ts); + if (cluster < 0) { + err = cluster; + goto out; + } + err = vfat_add_entry(dir, &dentry->d_name, 1, cluster, &ts, &sinfo); + if (err) + goto out_free; + inode_inc_iversion(dir); + inc_nlink(dir); + + inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); + brelse(sinfo.bh); + if (IS_ERR(inode)) { + err = PTR_ERR(inode); + /* the directory was completed, just return a error */ + goto out; + } + inode_inc_iversion(inode); + set_nlink(inode, 2); + + d_instantiate(dentry, inode); + + mutex_unlock(&MSDOS_SB(sb)->s_lock); + return 0; + +out_free: + fat_free_clusters(dir, cluster); +out: + mutex_unlock(&MSDOS_SB(sb)->s_lock); + return err; +} + +static int vfat_get_dotdot_de(struct inode *inode, struct buffer_head **bh, + struct msdos_dir_entry **de) +{ + if (S_ISDIR(inode->i_mode)) { + if (fat_get_dotdot_entry(inode, bh, de)) + return -EIO; + } + return 0; +} + +static int vfat_sync_ipos(struct inode *dir, struct inode *inode) +{ + if (IS_DIRSYNC(dir)) + return fat_sync_inode(inode); + mark_inode_dirty(inode); + return 0; +} + +static int vfat_update_dotdot_de(struct inode *dir, struct inode *inode, + struct buffer_head *dotdot_bh, + struct msdos_dir_entry *dotdot_de) +{ + fat_set_start(dotdot_de, MSDOS_I(dir)->i_logstart); + mark_buffer_dirty_inode(dotdot_bh, inode); + if (IS_DIRSYNC(dir)) + return sync_dirty_buffer(dotdot_bh); + return 0; +} + +static void vfat_update_dir_metadata(struct inode *dir, struct timespec64 *ts) +{ + inode_inc_iversion(dir); + fat_truncate_time(dir, ts, S_CTIME | S_MTIME); + if (IS_DIRSYNC(dir)) + (void)fat_sync_inode(dir); + else + mark_inode_dirty(dir); +} + +static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry) +{ + struct buffer_head *dotdot_bh; + struct msdos_dir_entry *dotdot_de = NULL; + struct inode *old_inode, *new_inode; + struct fat_slot_info old_sinfo, sinfo; + struct timespec64 ts; + loff_t new_i_pos; + int err, is_dir, corrupt = 0; + struct super_block *sb = old_dir->i_sb; + + old_sinfo.bh = sinfo.bh = dotdot_bh = NULL; + old_inode = d_inode(old_dentry); + new_inode = d_inode(new_dentry); + mutex_lock(&MSDOS_SB(sb)->s_lock); + err = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo); + if (err) + goto out; + + if (old_dir != new_dir) { + err = vfat_get_dotdot_de(old_inode, &dotdot_bh, &dotdot_de); + if (err) + goto out; + } + + is_dir = S_ISDIR(old_inode->i_mode); + ts = current_time(old_dir); + if (new_inode) { + if (is_dir) { + err = fat_dir_empty(new_inode); + if (err) + goto out; + } + new_i_pos = MSDOS_I(new_inode)->i_pos; + fat_detach(new_inode); + } else { + err = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir, 0, + &ts, &sinfo); + if (err) + goto out; + new_i_pos = sinfo.i_pos; + } + inode_inc_iversion(new_dir); + + fat_detach(old_inode); + fat_attach(old_inode, new_i_pos); + err = vfat_sync_ipos(new_dir, old_inode); + if (err) + goto error_inode; + + if (dotdot_de) { + err = vfat_update_dotdot_de(new_dir, old_inode, dotdot_bh, + dotdot_de); + if (err) + goto error_dotdot; + drop_nlink(old_dir); + if (!new_inode) + inc_nlink(new_dir); + } + + err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */ + old_sinfo.bh = NULL; + if (err) + goto error_dotdot; + vfat_update_dir_metadata(old_dir, &ts); + + if (new_inode) { + drop_nlink(new_inode); + if (is_dir) + drop_nlink(new_inode); + fat_truncate_time(new_inode, &ts, S_CTIME); + } +out: + brelse(sinfo.bh); + brelse(dotdot_bh); + brelse(old_sinfo.bh); + mutex_unlock(&MSDOS_SB(sb)->s_lock); + + return err; + +error_dotdot: + /* data cluster is shared, serious corruption */ + corrupt = 1; + + if (dotdot_de) { + corrupt |= vfat_update_dotdot_de(old_dir, old_inode, dotdot_bh, + dotdot_de); + } +error_inode: + fat_detach(old_inode); + fat_attach(old_inode, old_sinfo.i_pos); + if (new_inode) { + fat_attach(new_inode, new_i_pos); + if (corrupt) + corrupt |= fat_sync_inode(new_inode); + } else { + /* + * If new entry was not sharing the data cluster, it + * shouldn't be serious corruption. + */ + int err2 = fat_remove_entries(new_dir, &sinfo); + if (corrupt) + corrupt |= err2; + sinfo.bh = NULL; + } + if (corrupt < 0) { + fat_fs_error(new_dir->i_sb, + "%s: Filesystem corrupted (i_pos %lld)", + __func__, sinfo.i_pos); + } + goto out; +} + +static void vfat_exchange_ipos(struct inode *old_inode, struct inode *new_inode, + loff_t old_i_pos, loff_t new_i_pos) +{ + fat_detach(old_inode); + fat_detach(new_inode); + fat_attach(old_inode, new_i_pos); + fat_attach(new_inode, old_i_pos); +} + +static void vfat_move_nlink(struct inode *src, struct inode *dst) +{ + drop_nlink(src); + inc_nlink(dst); +} + +static int vfat_rename_exchange(struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry) +{ + struct buffer_head *old_dotdot_bh = NULL, *new_dotdot_bh = NULL; + struct msdos_dir_entry *old_dotdot_de = NULL, *new_dotdot_de = NULL; + struct inode *old_inode, *new_inode; + struct timespec64 ts = current_time(old_dir); + loff_t old_i_pos, new_i_pos; + int err, corrupt = 0; + struct super_block *sb = old_dir->i_sb; + + old_inode = d_inode(old_dentry); + new_inode = d_inode(new_dentry); + + /* Acquire super block lock for the operation to be atomic */ + mutex_lock(&MSDOS_SB(sb)->s_lock); + + /* if directories are not the same, get ".." info to update */ + if (old_dir != new_dir) { + err = vfat_get_dotdot_de(old_inode, &old_dotdot_bh, + &old_dotdot_de); + if (err) + goto out; + + err = vfat_get_dotdot_de(new_inode, &new_dotdot_bh, + &new_dotdot_de); + if (err) + goto out; + } + + old_i_pos = MSDOS_I(old_inode)->i_pos; + new_i_pos = MSDOS_I(new_inode)->i_pos; + + vfat_exchange_ipos(old_inode, new_inode, old_i_pos, new_i_pos); + + err = vfat_sync_ipos(old_dir, new_inode); + if (err) + goto error_exchange; + err = vfat_sync_ipos(new_dir, old_inode); + if (err) + goto error_exchange; + + /* update ".." directory entry info */ + if (old_dotdot_de) { + err = vfat_update_dotdot_de(new_dir, old_inode, old_dotdot_bh, + old_dotdot_de); + if (err) + goto error_old_dotdot; + } + if (new_dotdot_de) { + err = vfat_update_dotdot_de(old_dir, new_inode, new_dotdot_bh, + new_dotdot_de); + if (err) + goto error_new_dotdot; + } + + /* if cross directory and only one is a directory, adjust nlink */ + if (!old_dotdot_de != !new_dotdot_de) { + if (old_dotdot_de) + vfat_move_nlink(old_dir, new_dir); + else + vfat_move_nlink(new_dir, old_dir); + } + + vfat_update_dir_metadata(old_dir, &ts); + /* if directories are not the same, update new_dir as well */ + if (old_dir != new_dir) + vfat_update_dir_metadata(new_dir, &ts); + +out: + brelse(old_dotdot_bh); + brelse(new_dotdot_bh); + mutex_unlock(&MSDOS_SB(sb)->s_lock); + + return err; + +error_new_dotdot: + if (new_dotdot_de) { + corrupt |= vfat_update_dotdot_de(new_dir, new_inode, + new_dotdot_bh, new_dotdot_de); + } + +error_old_dotdot: + if (old_dotdot_de) { + corrupt |= vfat_update_dotdot_de(old_dir, old_inode, + old_dotdot_bh, old_dotdot_de); + } + +error_exchange: + vfat_exchange_ipos(old_inode, new_inode, new_i_pos, old_i_pos); + corrupt |= vfat_sync_ipos(new_dir, new_inode); + corrupt |= vfat_sync_ipos(old_dir, old_inode); + + if (corrupt < 0) { + fat_fs_error(new_dir->i_sb, + "%s: Filesystem corrupted (i_pos %lld, %lld)", + __func__, old_i_pos, new_i_pos); + } + goto out; +} + +static int vfat_rename2(struct user_namespace *mnt_userns, struct inode *old_dir, + struct dentry *old_dentry, struct inode *new_dir, + struct dentry *new_dentry, unsigned int flags) +{ + if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) + return -EINVAL; + + if (flags & RENAME_EXCHANGE) { + return vfat_rename_exchange(old_dir, old_dentry, + new_dir, new_dentry); + } + + /* VFS already handled RENAME_NOREPLACE, handle it as a normal rename */ + return vfat_rename(old_dir, old_dentry, new_dir, new_dentry); +} + +static const struct inode_operations vfat_dir_inode_operations = { + .create = vfat_create, + .lookup = vfat_lookup, + .unlink = vfat_unlink, + .mkdir = vfat_mkdir, + .rmdir = vfat_rmdir, + .rename = vfat_rename2, + .setattr = fat_setattr, + .getattr = fat_getattr, + .update_time = fat_update_time, +}; + +static void setup(struct super_block *sb) +{ + MSDOS_SB(sb)->dir_ops = &vfat_dir_inode_operations; + if (MSDOS_SB(sb)->options.name_check != 's') + sb->s_d_op = &vfat_ci_dentry_ops; + else + sb->s_d_op = &vfat_dentry_ops; +} + +static int vfat_fill_super(struct super_block *sb, void *data, int silent) +{ + return fat_fill_super(sb, data, silent, 1, setup); +} + +static struct dentry *vfat_mount(struct file_system_type *fs_type, + int flags, const char *dev_name, + void *data) +{ + return mount_bdev(fs_type, flags, dev_name, data, vfat_fill_super); +} + +static struct file_system_type vfat_fs_type = { + .owner = THIS_MODULE, + .name = "vfat", + .mount = vfat_mount, + .kill_sb = kill_block_super, + .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP, +}; +MODULE_ALIAS_FS("vfat"); + +static int __init init_vfat_fs(void) +{ + return register_filesystem(&vfat_fs_type); +} + +static void __exit exit_vfat_fs(void) +{ + unregister_filesystem(&vfat_fs_type); +} + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("VFAT filesystem support"); +MODULE_AUTHOR("Gordon Chaffee"); + +module_init(init_vfat_fs) +module_exit(exit_vfat_fs) |