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linux/fs/fat/dir.c
Arjan van de Ven 4b6f5d20b0 [PATCH] Make most file operations structs in fs/ const 
This is a conversion to make the various file_operations structs in fs/
const.  Basically a regexp job, with a few manual fixups

The goal is both to increase correctness (harder to accidentally write to
shared datastructures) and reducing the false sharing of cachelines with
things that get dirty in .data (while .rodata is nicely read only and thus
cache clean)

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 09:16:06 -08:00

1267 lines
31 KiB
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/*
* 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);
}
static inline void fat_dir_readahead(struct inode *dir, sector_t iblock,
sector_t phys)
{
struct super_block *sb = dir->i_sb;
struct msdos_sb_info *sbi = MSDOS_SB(sb);
struct buffer_head *bh;
int sec;
/* This is not a first sector of cluster, or sec_per_clus == 1 */
if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1)
return;
/* root dir of FAT12/FAT16 */
if ((sbi->fat_bits != 32) && (dir->i_ino == MSDOS_ROOT_INO))
return;
bh = sb_find_get_block(sb, phys);
if (bh == NULL || !buffer_uptodate(bh)) {
for (sec = 0; sec < sbi->sec_per_clus; sec++)
sb_breadahead(sb, phys + sec);
}
brelse(bh);
}
/* 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;
unsigned long mapped_blocks;
int err, offset;
next:
if (*bh)
brelse(*bh);
*bh = NULL;
iblock = *pos >> sb->s_blocksize_bits;
err = fat_bmap(dir, iblock, &phys, &mapped_blocks);
if (err || !phys)
return -1; /* beyond EOF or error */
fat_dir_readahead(dir, iblock, phys);
*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 UTF-8, 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;
}
enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, };
/**
* fat_parse_long - Parse extended directory entry.
*
* This function returns zero on success, negative value on error, or one of
* the following:
*
* %PARSE_INVALID - Directory entry is invalid.
* %PARSE_NOT_LONGNAME - Directory entry does not contain longname.
* %PARSE_EOF - Directory has no more entries.
*/
static int fat_parse_long(struct inode *dir, loff_t *pos,
struct buffer_head **bh, struct msdos_dir_entry **de,
wchar_t **unicode, unsigned char *nr_slots)
{
struct msdos_dir_slot *ds;
unsigned char id, slot, slots, 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))
return PARSE_INVALID;
slots = id & ~0x40;
if (slots > 20 || !slots) /* ceil(256 * 2 / 26) */
return PARSE_INVALID;
*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(dir, pos, bh, de) < 0)
return PARSE_EOF;
if (slot == 0)
break;
ds = (struct msdos_dir_slot *)*de;
if (ds->attr != ATTR_EXT)
return PARSE_NOT_LONGNAME;
if ((ds->id & ~0x40) != slot)
goto parse_long;
if (ds->alias_checksum != alias_checksum)
goto parse_long;
}
if ((*de)->name[0] == DELETED_FLAG)
return PARSE_INVALID;
if ((*de)->attr == ATTR_EXT)
goto parse_long;
if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME))
return PARSE_INVALID;
if (fat_checksum((*de)->name) != alias_checksum)
*nr_slots = 0;
return 0;
}
/*
* 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) {
int status = fat_parse_long(inode, &cpos, &bh, &de,
&unicode, &nr_slots);
if (status < 0)
return status;
else if (status == PARSE_INVALID)
continue;
else if (status == PARSE_NOT_LONGNAME)
goto parse_record;
else if (status == PARSE_EOF)
goto EODir;
}
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_GPL(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_readdir(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:
if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
goto EODir;
parse_record:
long_slots = 0;
/* 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) {
int status = fat_parse_long(inode, &cpos, &bh, &de,
&unicode, &long_slots);
if (status < 0) {
filp->f_pos = cpos;
ret = status;
goto out;
} else if (status == PARSE_INVALID)
goto RecEnd;
else if (status == PARSE_NOT_LONGNAME)
goto parse_record;
else if (status == PARSE_EOF)
goto EODir;
}
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:
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_readdir(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;
mutex_lock(&inode->i_mutex);
ret = -ENOENT;
if (!IS_DEADDIR(inode)) {
ret = __fat_readdir(inode, filp, &buf, fat_ioctl_filldir,
short_only, both);
}
mutex_unlock(&inode->i_mutex);
if (ret >= 0)
ret = buf.result;
return ret;
}
const 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_GPL(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_GPL(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_GPL(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_GPL(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_GPL(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_GPL(fat_add_entries);
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