diff options
Diffstat (limited to 'fs/fat/dir.c')
| -rw-r--r-- | fs/fat/dir.c | 1271 |
1 files changed, 1271 insertions, 0 deletions
diff --git a/fs/fat/dir.c b/fs/fat/dir.c new file mode 100644 index 000000000000..e5ae1b720dde --- /dev/null +++ b/fs/fat/dir.c @@ -0,0 +1,1271 @@ +/* + * linux/fs/fat/dir.c + * + * directory handling functions for fat-based filesystems + * + * Written 1992,1993 by Werner Almesberger + * + * Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu> + * + * VFAT extensions by Gordon Chaffee <chaffee@plateau.cs.berkeley.edu> + * Merged with msdos fs by Henrik Storner <storner@osiris.ping.dk> + * Rewritten for constant inumbers. Plugged buffer overrun in readdir(). AV + * Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de> + */ + +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/time.h> +#include <linux/msdos_fs.h> +#include <linux/dirent.h> +#include <linux/smp_lock.h> +#include <linux/buffer_head.h> +#include <asm/uaccess.h> + +static inline loff_t fat_make_i_pos(struct super_block *sb, + struct buffer_head *bh, + struct msdos_dir_entry *de) +{ + return ((loff_t)bh->b_blocknr << MSDOS_SB(sb)->dir_per_block_bits) + | (de - (struct msdos_dir_entry *)bh->b_data); +} + +/* Returns the inode number of the directory entry at offset pos. If bh is + non-NULL, it is brelse'd before. Pos is incremented. The buffer header is + returned in bh. + AV. Most often we do it item-by-item. Makes sense to optimize. + AV. OK, there we go: if both bh and de are non-NULL we assume that we just + AV. want the next entry (took one explicit de=NULL in vfat/namei.c). + AV. It's done in fat_get_entry() (inlined), here the slow case lives. + AV. Additionally, when we return -1 (i.e. reached the end of directory) + AV. we make bh NULL. + */ +static int fat__get_entry(struct inode *dir, loff_t *pos, + struct buffer_head **bh, struct msdos_dir_entry **de) +{ + struct super_block *sb = dir->i_sb; + sector_t phys, iblock; + int offset; + int err; + +next: + if (*bh) + brelse(*bh); + + *bh = NULL; + iblock = *pos >> sb->s_blocksize_bits; + err = fat_bmap(dir, iblock, &phys); + if (err || !phys) + return -1; /* beyond EOF or error */ + + *bh = sb_bread(sb, phys); + if (*bh == NULL) { + printk(KERN_ERR "FAT: Directory bread(block %llu) failed\n", + (unsigned long long)phys); + /* skip this block */ + *pos = (iblock + 1) << sb->s_blocksize_bits; + goto next; + } + + offset = *pos & (sb->s_blocksize - 1); + *pos += sizeof(struct msdos_dir_entry); + *de = (struct msdos_dir_entry *)((*bh)->b_data + offset); + + return 0; +} + +static inline int fat_get_entry(struct inode *dir, loff_t *pos, + struct buffer_head **bh, + struct msdos_dir_entry **de) +{ + /* Fast stuff first */ + if (*bh && *de && + (*de - (struct msdos_dir_entry *)(*bh)->b_data) < MSDOS_SB(dir->i_sb)->dir_per_block - 1) { + *pos += sizeof(struct msdos_dir_entry); + (*de)++; + return 0; + } + return fat__get_entry(dir, pos, bh, de); +} + +/* + * Convert Unicode 16 to UTF8, translated Unicode, or ASCII. + * If uni_xlate is enabled and we can't get a 1:1 conversion, use a + * colon as an escape character since it is normally invalid on the vfat + * filesystem. The following four characters are the hexadecimal digits + * of Unicode value. This lets us do a full dump and restore of Unicode + * filenames. We could get into some trouble with long Unicode names, + * but ignore that right now. + * Ahem... Stack smashing in ring 0 isn't fun. Fixed. + */ +static int uni16_to_x8(unsigned char *ascii, wchar_t *uni, int uni_xlate, + struct nls_table *nls) +{ + wchar_t *ip, ec; + unsigned char *op, nc; + int charlen; + int k; + + ip = uni; + op = ascii; + + while (*ip) { + ec = *ip++; + if ( (charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE)) > 0) { + op += charlen; + } else { + if (uni_xlate == 1) { + *op = ':'; + for (k = 4; k > 0; k--) { + nc = ec & 0xF; + op[k] = nc > 9 ? nc + ('a' - 10) + : nc + '0'; + ec >>= 4; + } + op += 5; + } else { + *op++ = '?'; + } + } + /* We have some slack there, so it's OK */ + if (op>ascii+256) { + op = ascii + 256; + break; + } + } + *op = 0; + return (op - ascii); +} + +static inline int +fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni) +{ + int charlen; + + charlen = t->char2uni(c, clen, uni); + if (charlen < 0) { + *uni = 0x003f; /* a question mark */ + charlen = 1; + } + return charlen; +} + +static inline int +fat_short2lower_uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni) +{ + int charlen; + wchar_t wc; + + charlen = t->char2uni(c, clen, &wc); + if (charlen < 0) { + *uni = 0x003f; /* a question mark */ + charlen = 1; + } else if (charlen <= 1) { + unsigned char nc = t->charset2lower[*c]; + + if (!nc) + nc = *c; + + if ( (charlen = t->char2uni(&nc, 1, uni)) < 0) { + *uni = 0x003f; /* a question mark */ + charlen = 1; + } + } else + *uni = wc; + + return charlen; +} + +static inline int +fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size, + wchar_t *uni_buf, unsigned short opt, int lower) +{ + int len = 0; + + if (opt & VFAT_SFN_DISPLAY_LOWER) + len = fat_short2lower_uni(nls, buf, buf_size, uni_buf); + else if (opt & VFAT_SFN_DISPLAY_WIN95) + len = fat_short2uni(nls, buf, buf_size, uni_buf); + else if (opt & VFAT_SFN_DISPLAY_WINNT) { + if (lower) + len = fat_short2lower_uni(nls, buf, buf_size, uni_buf); + else + len = fat_short2uni(nls, buf, buf_size, uni_buf); + } else + len = fat_short2uni(nls, buf, buf_size, uni_buf); + + return len; +} + +/* + * Return values: negative -> error, 0 -> not found, positive -> found, + * value is the total amount of slots, including the shortname entry. + */ +int fat_search_long(struct inode *inode, const unsigned char *name, + int name_len, struct fat_slot_info *sinfo) +{ + struct super_block *sb = inode->i_sb; + struct msdos_sb_info *sbi = MSDOS_SB(sb); + struct buffer_head *bh = NULL; + struct msdos_dir_entry *de; + struct nls_table *nls_io = sbi->nls_io; + struct nls_table *nls_disk = sbi->nls_disk; + wchar_t bufuname[14]; + unsigned char xlate_len, nr_slots; + wchar_t *unicode = NULL; + unsigned char work[8], bufname[260]; /* 256 + 4 */ + int uni_xlate = sbi->options.unicode_xlate; + int utf8 = sbi->options.utf8; + int anycase = (sbi->options.name_check != 's'); + unsigned short opt_shortname = sbi->options.shortname; + loff_t cpos = 0; + int chl, i, j, last_u, err; + + err = -ENOENT; + while(1) { + if (fat_get_entry(inode, &cpos, &bh, &de) == -1) + goto EODir; +parse_record: + nr_slots = 0; + if (de->name[0] == DELETED_FLAG) + continue; + if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME)) + continue; + if (de->attr != ATTR_EXT && IS_FREE(de->name)) + continue; + if (de->attr == ATTR_EXT) { + struct msdos_dir_slot *ds; + unsigned char id; + unsigned char slot; + unsigned char slots; + unsigned char sum; + unsigned char alias_checksum; + + if (!unicode) { + unicode = (wchar_t *) + __get_free_page(GFP_KERNEL); + if (!unicode) { + brelse(bh); + return -ENOMEM; + } + } +parse_long: + slots = 0; + ds = (struct msdos_dir_slot *) de; + id = ds->id; + if (!(id & 0x40)) + continue; + slots = id & ~0x40; + if (slots > 20 || !slots) /* ceil(256 * 2 / 26) */ + continue; + nr_slots = slots; + alias_checksum = ds->alias_checksum; + + slot = slots; + while (1) { + int offset; + + slot--; + offset = slot * 13; + fat16_towchar(unicode + offset, ds->name0_4, 5); + fat16_towchar(unicode + offset + 5, ds->name5_10, 6); + fat16_towchar(unicode + offset + 11, ds->name11_12, 2); + + if (ds->id & 0x40) { + unicode[offset + 13] = 0; + } + if (fat_get_entry(inode, &cpos, &bh, &de) < 0) + goto EODir; + if (slot == 0) + break; + ds = (struct msdos_dir_slot *) de; + if (ds->attr != ATTR_EXT) + goto parse_record; + if ((ds->id & ~0x40) != slot) + goto parse_long; + if (ds->alias_checksum != alias_checksum) + goto parse_long; + } + if (de->name[0] == DELETED_FLAG) + continue; + if (de->attr == ATTR_EXT) + goto parse_long; + if (IS_FREE(de->name) || (de->attr & ATTR_VOLUME)) + continue; + for (sum = 0, i = 0; i < 11; i++) + sum = (((sum&1)<<7)|((sum&0xfe)>>1)) + de->name[i]; + if (sum != alias_checksum) + nr_slots = 0; + } + + memcpy(work, de->name, sizeof(de->name)); + /* see namei.c, msdos_format_name */ + if (work[0] == 0x05) + work[0] = 0xE5; + for (i = 0, j = 0, last_u = 0; i < 8;) { + if (!work[i]) break; + chl = fat_shortname2uni(nls_disk, &work[i], 8 - i, + &bufuname[j++], opt_shortname, + de->lcase & CASE_LOWER_BASE); + if (chl <= 1) { + if (work[i] != ' ') + last_u = j; + } else { + last_u = j; + } + i += chl; + } + j = last_u; + fat_short2uni(nls_disk, ".", 1, &bufuname[j++]); + for (i = 0; i < 3;) { + if (!de->ext[i]) break; + chl = fat_shortname2uni(nls_disk, &de->ext[i], 3 - i, + &bufuname[j++], opt_shortname, + de->lcase & CASE_LOWER_EXT); + if (chl <= 1) { + if (de->ext[i] != ' ') + last_u = j; + } else { + last_u = j; + } + i += chl; + } + if (!last_u) + continue; + + bufuname[last_u] = 0x0000; + xlate_len = utf8 + ?utf8_wcstombs(bufname, bufuname, sizeof(bufname)) + :uni16_to_x8(bufname, bufuname, uni_xlate, nls_io); + if (xlate_len == name_len) + if ((!anycase && !memcmp(name, bufname, xlate_len)) || + (anycase && !nls_strnicmp(nls_io, name, bufname, + xlate_len))) + goto Found; + + if (nr_slots) { + xlate_len = utf8 + ?utf8_wcstombs(bufname, unicode, sizeof(bufname)) + :uni16_to_x8(bufname, unicode, uni_xlate, nls_io); + if (xlate_len != name_len) + continue; + if ((!anycase && !memcmp(name, bufname, xlate_len)) || + (anycase && !nls_strnicmp(nls_io, name, bufname, + xlate_len))) + goto Found; + } + } + +Found: + nr_slots++; /* include the de */ + sinfo->slot_off = cpos - nr_slots * sizeof(*de); + sinfo->nr_slots = nr_slots; + sinfo->de = de; + sinfo->bh = bh; + sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de); + err = 0; +EODir: + if (unicode) + free_page((unsigned long)unicode); + + return err; +} + +EXPORT_SYMBOL(fat_search_long); + +struct fat_ioctl_filldir_callback { + struct dirent __user *dirent; + int result; + /* for dir ioctl */ + const char *longname; + int long_len; + const char *shortname; + int short_len; +}; + +static int fat_readdirx(struct inode *inode, struct file *filp, void *dirent, + filldir_t filldir, int short_only, int both) +{ + struct super_block *sb = inode->i_sb; + struct msdos_sb_info *sbi = MSDOS_SB(sb); + struct buffer_head *bh; + struct msdos_dir_entry *de; + struct nls_table *nls_io = sbi->nls_io; + struct nls_table *nls_disk = sbi->nls_disk; + unsigned char long_slots; + const char *fill_name; + int fill_len; + wchar_t bufuname[14]; + wchar_t *unicode = NULL; + unsigned char c, work[8], bufname[56], *ptname = bufname; + unsigned long lpos, dummy, *furrfu = &lpos; + int uni_xlate = sbi->options.unicode_xlate; + int isvfat = sbi->options.isvfat; + int utf8 = sbi->options.utf8; + int nocase = sbi->options.nocase; + unsigned short opt_shortname = sbi->options.shortname; + unsigned long inum; + int chi, chl, i, i2, j, last, last_u, dotoffset = 0; + loff_t cpos; + int ret = 0; + + lock_kernel(); + + cpos = filp->f_pos; + /* Fake . and .. for the root directory. */ + if (inode->i_ino == MSDOS_ROOT_INO) { + while (cpos < 2) { + if (filldir(dirent, "..", cpos+1, cpos, MSDOS_ROOT_INO, DT_DIR) < 0) + goto out; + cpos++; + filp->f_pos++; + } + if (cpos == 2) { + dummy = 2; + furrfu = &dummy; + cpos = 0; + } + } + if (cpos & (sizeof(struct msdos_dir_entry)-1)) { + ret = -ENOENT; + goto out; + } + + bh = NULL; +GetNew: + long_slots = 0; + if (fat_get_entry(inode, &cpos, &bh, &de) == -1) + goto EODir; + /* Check for long filename entry */ + if (isvfat) { + if (de->name[0] == DELETED_FLAG) + goto RecEnd; + if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME)) + goto RecEnd; + if (de->attr != ATTR_EXT && IS_FREE(de->name)) + goto RecEnd; + } else { + if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name)) + goto RecEnd; + } + + if (isvfat && de->attr == ATTR_EXT) { + struct msdos_dir_slot *ds; + unsigned char id; + unsigned char slot; + unsigned char slots; + unsigned char sum; + unsigned char alias_checksum; + + if (!unicode) { + unicode = (wchar_t *)__get_free_page(GFP_KERNEL); + if (!unicode) { + filp->f_pos = cpos; + brelse(bh); + ret = -ENOMEM; + goto out; + } + } +ParseLong: + slots = 0; + ds = (struct msdos_dir_slot *) de; + id = ds->id; + if (!(id & 0x40)) + goto RecEnd; + slots = id & ~0x40; + if (slots > 20 || !slots) /* ceil(256 * 2 / 26) */ + goto RecEnd; + long_slots = slots; + alias_checksum = ds->alias_checksum; + + slot = slots; + while (1) { + int offset; + + slot--; + offset = slot * 13; + fat16_towchar(unicode + offset, ds->name0_4, 5); + fat16_towchar(unicode + offset + 5, ds->name5_10, 6); + fat16_towchar(unicode + offset + 11, ds->name11_12, 2); + + if (ds->id & 0x40) { + unicode[offset + 13] = 0; + } + if (fat_get_entry(inode, &cpos, &bh, &de) == -1) + goto EODir; + if (slot == 0) + break; + ds = (struct msdos_dir_slot *) de; + if (ds->attr != ATTR_EXT) + goto RecEnd; /* XXX */ + if ((ds->id & ~0x40) != slot) + goto ParseLong; + if (ds->alias_checksum != alias_checksum) + goto ParseLong; + } + if (de->name[0] == DELETED_FLAG) + goto RecEnd; + if (de->attr == ATTR_EXT) + goto ParseLong; + if (IS_FREE(de->name) || (de->attr & ATTR_VOLUME)) + goto RecEnd; + for (sum = 0, i = 0; i < 11; i++) + sum = (((sum&1)<<7)|((sum&0xfe)>>1)) + de->name[i]; + if (sum != alias_checksum) + long_slots = 0; + } + + if (sbi->options.dotsOK) { + ptname = bufname; + dotoffset = 0; + if (de->attr & ATTR_HIDDEN) { + *ptname++ = '.'; + dotoffset = 1; + } + } + + memcpy(work, de->name, sizeof(de->name)); + /* see namei.c, msdos_format_name */ + if (work[0] == 0x05) + work[0] = 0xE5; + for (i = 0, j = 0, last = 0, last_u = 0; i < 8;) { + if (!(c = work[i])) break; + chl = fat_shortname2uni(nls_disk, &work[i], 8 - i, + &bufuname[j++], opt_shortname, + de->lcase & CASE_LOWER_BASE); + if (chl <= 1) { + ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c; + if (c != ' ') { + last = i; + last_u = j; + } + } else { + last_u = j; + for (chi = 0; chi < chl && i < 8; chi++) { + ptname[i] = work[i]; + i++; last = i; + } + } + } + i = last; + j = last_u; + fat_short2uni(nls_disk, ".", 1, &bufuname[j++]); + ptname[i++] = '.'; + for (i2 = 0; i2 < 3;) { + if (!(c = de->ext[i2])) break; + chl = fat_shortname2uni(nls_disk, &de->ext[i2], 3 - i2, + &bufuname[j++], opt_shortname, + de->lcase & CASE_LOWER_EXT); + if (chl <= 1) { + i2++; + ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c; + if (c != ' ') { + last = i; + last_u = j; + } + } else { + last_u = j; + for (chi = 0; chi < chl && i2 < 3; chi++) { + ptname[i++] = de->ext[i2++]; + last = i; + } + } + } + if (!last) + goto RecEnd; + + i = last + dotoffset; + j = last_u; + + lpos = cpos - (long_slots+1)*sizeof(struct msdos_dir_entry); + if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME)) + inum = inode->i_ino; + else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) { + inum = parent_ino(filp->f_dentry); + } else { + loff_t i_pos = fat_make_i_pos(sb, bh, de); + struct inode *tmp = fat_iget(sb, i_pos); + if (tmp) { + inum = tmp->i_ino; + iput(tmp); + } else + inum = iunique(sb, MSDOS_ROOT_INO); + } + + if (isvfat) { + bufuname[j] = 0x0000; + i = utf8 ? utf8_wcstombs(bufname, bufuname, sizeof(bufname)) + : uni16_to_x8(bufname, bufuname, uni_xlate, nls_io); + } + + fill_name = bufname; + fill_len = i; + if (!short_only && long_slots) { + /* convert the unicode long name. 261 is maximum size + * of unicode buffer. (13 * slots + nul) */ + void *longname = unicode + 261; + int buf_size = PAGE_SIZE - (261 * sizeof(unicode[0])); + int long_len = utf8 + ? utf8_wcstombs(longname, unicode, buf_size) + : uni16_to_x8(longname, unicode, uni_xlate, nls_io); + + if (!both) { + fill_name = longname; + fill_len = long_len; + } else { + /* hack for fat_ioctl_filldir() */ + struct fat_ioctl_filldir_callback *p = dirent; + + p->longname = longname; + p->long_len = long_len; + p->shortname = bufname; + p->short_len = i; + fill_name = NULL; + fill_len = 0; + } + } + if (filldir(dirent, fill_name, fill_len, *furrfu, inum, + (de->attr & ATTR_DIR) ? DT_DIR : DT_REG) < 0) + goto FillFailed; + +RecEnd: + furrfu = &lpos; + filp->f_pos = cpos; + goto GetNew; +EODir: + filp->f_pos = cpos; +FillFailed: + if (bh) + brelse(bh); + if (unicode) + free_page((unsigned long)unicode); +out: + unlock_kernel(); + return ret; +} + +static int fat_readdir(struct file *filp, void *dirent, filldir_t filldir) +{ + struct inode *inode = filp->f_dentry->d_inode; + return fat_readdirx(inode, filp, dirent, filldir, 0, 0); +} + +static int fat_ioctl_filldir(void *__buf, const char *name, int name_len, + loff_t offset, ino_t ino, unsigned int d_type) +{ + struct fat_ioctl_filldir_callback *buf = __buf; + struct dirent __user *d1 = buf->dirent; + struct dirent __user *d2 = d1 + 1; + + if (buf->result) + return -EINVAL; + buf->result++; + + if (name != NULL) { + /* dirent has only short name */ + if (name_len >= sizeof(d1->d_name)) + name_len = sizeof(d1->d_name) - 1; + + if (put_user(0, d2->d_name) || + put_user(0, &d2->d_reclen) || + copy_to_user(d1->d_name, name, name_len) || + put_user(0, d1->d_name + name_len) || + put_user(name_len, &d1->d_reclen)) + goto efault; + } else { + /* dirent has short and long name */ + const char *longname = buf->longname; + int long_len = buf->long_len; + const char *shortname = buf->shortname; + int short_len = buf->short_len; + + if (long_len >= sizeof(d1->d_name)) + long_len = sizeof(d1->d_name) - 1; + if (short_len >= sizeof(d1->d_name)) + short_len = sizeof(d1->d_name) - 1; + + if (copy_to_user(d2->d_name, longname, long_len) || + put_user(0, d2->d_name + long_len) || + put_user(long_len, &d2->d_reclen) || + put_user(ino, &d2->d_ino) || + put_user(offset, &d2->d_off) || + copy_to_user(d1->d_name, shortname, short_len) || + put_user(0, d1->d_name + short_len) || + put_user(short_len, &d1->d_reclen)) + goto efault; + } + return 0; +efault: + buf->result = -EFAULT; + return -EFAULT; +} + +static int fat_dir_ioctl(struct inode * inode, struct file * filp, + unsigned int cmd, unsigned long arg) +{ + struct fat_ioctl_filldir_callback buf; + struct dirent __user *d1; + int ret, short_only, both; + + switch (cmd) { + case VFAT_IOCTL_READDIR_SHORT: + short_only = 1; + both = 0; + break; + case VFAT_IOCTL_READDIR_BOTH: + short_only = 0; + both = 1; + break; + default: + return fat_generic_ioctl(inode, filp, cmd, arg); + } + + d1 = (struct dirent __user *)arg; + if (!access_ok(VERIFY_WRITE, d1, sizeof(struct dirent[2]))) + return -EFAULT; + /* + * Yes, we don't need this put_user() absolutely. However old + * code didn't return the right value. So, app use this value, + * in order to check whether it is EOF. + */ + if (put_user(0, &d1->d_reclen)) + return -EFAULT; + + buf.dirent = d1; + buf.result = 0; + down(&inode->i_sem); + ret = -ENOENT; + if (!IS_DEADDIR(inode)) { + ret = fat_readdirx(inode, filp, &buf, fat_ioctl_filldir, + short_only, both); + } + up(&inode->i_sem); + if (ret >= 0) + ret = buf.result; + return ret; +} + +struct file_operations fat_dir_operations = { + .read = generic_read_dir, + .readdir = fat_readdir, + .ioctl = fat_dir_ioctl, + .fsync = file_fsync, +}; + +static int fat_get_short_entry(struct inode *dir, loff_t *pos, + struct buffer_head **bh, + struct msdos_dir_entry **de) +{ + while (fat_get_entry(dir, pos, bh, de) >= 0) { + /* free entry or long name entry or volume label */ + if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME)) + return 0; + } + return -ENOENT; +} + +/* + * The ".." entry can not provide the "struct fat_slot_info" informations + * for inode. So, this function provide the some informations only. + */ +int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh, + struct msdos_dir_entry **de, loff_t *i_pos) +{ + loff_t offset; + + offset = 0; + *bh = NULL; + while (fat_get_short_entry(dir, &offset, bh, de) >= 0) { + if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME)) { + *i_pos = fat_make_i_pos(dir->i_sb, *bh, *de); + return 0; + } + } + return -ENOENT; +} + +EXPORT_SYMBOL(fat_get_dotdot_entry); + +/* See if directory is empty */ +int fat_dir_empty(struct inode *dir) +{ + struct buffer_head *bh; + struct msdos_dir_entry *de; + loff_t cpos; + int result = 0; + + bh = NULL; + cpos = 0; + while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) { + if (strncmp(de->name, MSDOS_DOT , MSDOS_NAME) && + strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) { + result = -ENOTEMPTY; + break; + } + } + brelse(bh); + return result; +} + +EXPORT_SYMBOL(fat_dir_empty); + +/* + * fat_subdirs counts the number of sub-directories of dir. It can be run + * on directories being created. + */ +int fat_subdirs(struct inode *dir) +{ + struct buffer_head *bh; + struct msdos_dir_entry *de; + loff_t cpos; + int count = 0; + + bh = NULL; + cpos = 0; + while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) { + if (de->attr & ATTR_DIR) + count++; + } + brelse(bh); + return count; +} + +/* + * Scans a directory for a given file (name points to its formatted name). + * Returns an error code or zero. + */ +int fat_scan(struct inode *dir, const unsigned char *name, + struct fat_slot_info *sinfo) +{ + struct super_block *sb = dir->i_sb; + + sinfo->slot_off = 0; + sinfo->bh = NULL; + while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh, + &sinfo->de) >= 0) { + if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) { + sinfo->slot_off -= sizeof(*sinfo->de); + sinfo->nr_slots = 1; + sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de); + return 0; + } + } + return -ENOENT; +} + +EXPORT_SYMBOL(fat_scan); + +static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots) +{ + struct super_block *sb = dir->i_sb; + struct buffer_head *bh; + struct msdos_dir_entry *de, *endp; + int err = 0, orig_slots; + + while (nr_slots) { + bh = NULL; + if (fat_get_entry(dir, &pos, &bh, &de) < 0) { + err = -EIO; + break; + } + + orig_slots = nr_slots; + endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize); + while (nr_slots && de < endp) { + de->name[0] = DELETED_FLAG; + de++; + nr_slots--; + } + mark_buffer_dirty(bh); + if (IS_DIRSYNC(dir)) + err = sync_dirty_buffer(bh); + brelse(bh); + if (err) + break; + + /* pos is *next* de's position, so this does `- sizeof(de)' */ + pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de); + } + + return err; +} + +int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo) +{ + struct msdos_dir_entry *de; + struct buffer_head *bh; + int err = 0, nr_slots; + + /* + * First stage: Remove the shortname. By this, the directory + * entry is removed. + */ + nr_slots = sinfo->nr_slots; + de = sinfo->de; + sinfo->de = NULL; + bh = sinfo->bh; + sinfo->bh = NULL; + while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) { + de->name[0] = DELETED_FLAG; + de--; + nr_slots--; + } + mark_buffer_dirty(bh); + if (IS_DIRSYNC(dir)) + err = sync_dirty_buffer(bh); + brelse(bh); + if (err) + return err; + dir->i_version++; + + if (nr_slots) { + /* + * Second stage: remove the remaining longname slots. + * (This directory entry is already removed, and so return + * the success) + */ + err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots); + if (err) { + printk(KERN_WARNING + "FAT: Couldn't remove the long name slots\n"); + } + } + + dir->i_mtime = dir->i_atime = CURRENT_TIME_SEC; + if (IS_DIRSYNC(dir)) + (void)fat_sync_inode(dir); + else + mark_inode_dirty(dir); + + return 0; +} + +EXPORT_SYMBOL(fat_remove_entries); + +static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used, + struct buffer_head **bhs, int nr_bhs) +{ + struct super_block *sb = dir->i_sb; + sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus; + int err, i, n; + + /* Zeroing the unused blocks on this cluster */ + blknr += nr_used; + n = nr_used; + while (blknr < last_blknr) { + bhs[n] = sb_getblk(sb, blknr); + if (!bhs[n]) { + err = -ENOMEM; + goto error; + } + memset(bhs[n]->b_data, 0, sb->s_blocksize); + set_buffer_uptodate(bhs[n]); + mark_buffer_dirty(bhs[n]); + + n++; + blknr++; + if (n == nr_bhs) { + if (IS_DIRSYNC(dir)) { + err = fat_sync_bhs(bhs, n); + if (err) + goto error; + } + for (i = 0; i < n; i++) + brelse(bhs[i]); + n = 0; + } + } + if (IS_DIRSYNC(dir)) { + err = fat_sync_bhs(bhs, n); + if (err) + goto error; + } + for (i = 0; i < n; i++) + brelse(bhs[i]); + + return 0; + +error: + for (i = 0; i < n; i++) + bforget(bhs[i]); + return err; +} + +int fat_alloc_new_dir(struct inode *dir, struct timespec *ts) +{ + struct super_block *sb = dir->i_sb; + struct msdos_sb_info *sbi = MSDOS_SB(sb); + struct buffer_head *bhs[MAX_BUF_PER_PAGE]; + struct msdos_dir_entry *de; + sector_t blknr; + __le16 date, time; + int err, cluster; + + err = fat_alloc_clusters(dir, &cluster, 1); + if (err) + goto error; + + blknr = fat_clus_to_blknr(sbi, cluster); + bhs[0] = sb_getblk(sb, blknr); + if (!bhs[0]) { + err = -ENOMEM; + goto error_free; + } + + fat_date_unix2dos(ts->tv_sec, &time, &date); + + de = (struct msdos_dir_entry *)bhs[0]->b_data; + /* filling the new directory slots ("." and ".." entries) */ + memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME); + memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME); + de->attr = de[1].attr = ATTR_DIR; + de[0].lcase = de[1].lcase = 0; + de[0].time = de[1].time = time; + de[0].date = de[1].date = date; + de[0].ctime_cs = de[1].ctime_cs = 0; + if (sbi->options.isvfat) { + /* extra timestamps */ + de[0].ctime = de[1].ctime = time; + de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date; + } else { + de[0].ctime = de[1].ctime = 0; + de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0; + } + de[0].start = cpu_to_le16(cluster); + de[0].starthi = cpu_to_le16(cluster >> 16); + de[1].start = cpu_to_le16(MSDOS_I(dir)->i_logstart); + de[1].starthi = cpu_to_le16(MSDOS_I(dir)->i_logstart >> 16); + de[0].size = de[1].size = 0; + memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de)); + set_buffer_uptodate(bhs[0]); + mark_buffer_dirty(bhs[0]); + + err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE); + if (err) + goto error_free; + + return cluster; + +error_free: + fat_free_clusters(dir, cluster); +error: + return err; +} + +EXPORT_SYMBOL(fat_alloc_new_dir); + +static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots, + int *nr_cluster, struct msdos_dir_entry **de, + struct buffer_head **bh, loff_t *i_pos) +{ + struct super_block *sb = dir->i_sb; + struct msdos_sb_info *sbi = MSDOS_SB(sb); + struct buffer_head *bhs[MAX_BUF_PER_PAGE]; + sector_t blknr, start_blknr, last_blknr; + unsigned long size, copy; + int err, i, n, offset, cluster[2]; + + /* + * The minimum cluster size is 512bytes, and maximum entry + * size is 32*slots (672bytes). So, iff the cluster size is + * 512bytes, we may need two clusters. + */ + size = nr_slots * sizeof(struct msdos_dir_entry); + *nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits; + BUG_ON(*nr_cluster > 2); + + err = fat_alloc_clusters(dir, cluster, *nr_cluster); + if (err) + goto error; + + /* + * First stage: Fill the directory entry. NOTE: This cluster + * is not referenced from any inode yet, so updates order is + * not important. + */ + i = n = copy = 0; + do { + start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]); + last_blknr = start_blknr + sbi->sec_per_clus; + while (blknr < last_blknr) { + bhs[n] = sb_getblk(sb, blknr); + if (!bhs[n]) { + err = -ENOMEM; + goto error_nomem; + } + + /* fill the directory entry */ + copy = min(size, sb->s_blocksize); + memcpy(bhs[n]->b_data, slots, copy); + slots += copy; + size -= copy; + set_buffer_uptodate(bhs[n]); + mark_buffer_dirty(bhs[n]); + if (!size) + break; + n++; + blknr++; + } + } while (++i < *nr_cluster); + + memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy); + offset = copy - sizeof(struct msdos_dir_entry); + get_bh(bhs[n]); + *bh = bhs[n]; + *de = (struct msdos_dir_entry *)((*bh)->b_data + offset); + *i_pos = fat_make_i_pos(sb, *bh, *de); + + /* Second stage: clear the rest of cluster, and write outs */ + err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE); + if (err) + goto error_free; + + return cluster[0]; + +error_free: + brelse(*bh); + *bh = NULL; + n = 0; +error_nomem: + for (i = 0; i < n; i++) + bforget(bhs[i]); + fat_free_clusters(dir, cluster[0]); +error: + return err; +} + +int fat_add_entries(struct inode *dir, void *slots, int nr_slots, + struct fat_slot_info *sinfo) +{ + struct super_block *sb = dir->i_sb; + struct msdos_sb_info *sbi = MSDOS_SB(sb); + struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */ + struct msdos_dir_entry *de; + int err, free_slots, i, nr_bhs; + loff_t pos, i_pos; + + sinfo->nr_slots = nr_slots; + + /* First stage: search free direcotry entries */ + free_slots = nr_bhs = 0; + bh = prev = NULL; + pos = 0; + err = -ENOSPC; + while (fat_get_entry(dir, &pos, &bh, &de) > -1) { + /* check the maximum size of directory */ + if (pos >= FAT_MAX_DIR_SIZE) + goto error; + + if (IS_FREE(de->name)) { + if (prev != bh) { + get_bh(bh); + bhs[nr_bhs] = prev = bh; + nr_bhs++; + } + free_slots++; + if (free_slots == nr_slots) + goto found; + } else { + for (i = 0; i < nr_bhs; i++) + brelse(bhs[i]); + prev = NULL; + free_slots = nr_bhs = 0; + } + } + if (dir->i_ino == MSDOS_ROOT_INO) { + if (sbi->fat_bits != 32) + goto error; + } else if (MSDOS_I(dir)->i_start == 0) { + printk(KERN_ERR "FAT: Corrupted directory (i_pos %lld)\n", + MSDOS_I(dir)->i_pos); + err = -EIO; + goto error; + } + +found: + err = 0; + pos -= free_slots * sizeof(*de); + nr_slots -= free_slots; + if (free_slots) { + /* + * Second stage: filling the free entries with new entries. + * NOTE: If this slots has shortname, first, we write + * the long name slots, then write the short name. + */ + int size = free_slots * sizeof(*de); + int offset = pos & (sb->s_blocksize - 1); + int long_bhs = nr_bhs - (nr_slots == 0); + + /* Fill the long name slots. */ + for (i = 0; i < long_bhs; i++) { + int copy = min_t(int, sb->s_blocksize - offset, size); + memcpy(bhs[i]->b_data + offset, slots, copy); + mark_buffer_dirty(bhs[i]); + offset = 0; + slots += copy; + size -= copy; + } + if (long_bhs && IS_DIRSYNC(dir)) + err = fat_sync_bhs(bhs, long_bhs); + if (!err && i < nr_bhs) { + /* Fill the short name slot. */ + int copy = min_t(int, sb->s_blocksize - offset, size); + memcpy(bhs[i]->b_data + offset, slots, copy); + mark_buffer_dirty(bhs[i]); + if (IS_DIRSYNC(dir)) + err = sync_dirty_buffer(bhs[i]); + } + for (i = 0; i < nr_bhs; i++) + brelse(bhs[i]); + if (err) + goto error_remove; + } + + if (nr_slots) { + int cluster, nr_cluster; + + /* + * Third stage: allocate the cluster for new entries. + * And initialize the cluster with new entries, then + * add the cluster to dir. + */ + cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster, + &de, &bh, &i_pos); + if (cluster < 0) { + err = cluster; + goto error_remove; + } + err = fat_chain_add(dir, cluster, nr_cluster); + if (err) { + fat_free_clusters(dir, cluster); + goto error_remove; + } + if (dir->i_size & (sbi->cluster_size - 1)) { + fat_fs_panic(sb, "Odd directory size"); + dir->i_size = (dir->i_size + sbi->cluster_size - 1) + & ~((loff_t)sbi->cluster_size - 1); + } + dir->i_size += nr_cluster << sbi->cluster_bits; + MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits; + } + sinfo->slot_off = pos; + sinfo->de = de; + sinfo->bh = bh; + sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de); + + return 0; + +error: + brelse(bh); + for (i = 0; i < nr_bhs; i++) + brelse(bhs[i]); + return err; + +error_remove: + brelse(bh); + if (free_slots) + __fat_remove_entries(dir, pos, free_slots); + return err; +} + +EXPORT_SYMBOL(fat_add_entries); |