Skip to content

Commit

Permalink
[PATCH] fat: Remove duplicate directory scanning code
Browse files Browse the repository at this point in the history 
This patch removes duplicate directory scanning code from fs/fat/dir.c.  The
two functions that share identical code are fat_readdirx() and
fat_search_long().  This patch also renames fat_readdirx to __fat_readdir().

Signed-off-by: Pekka Enberg <[email protected]>
Signed-off-by: OGAWA Hirofumi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
  • Loading branch information
Pekka Enberg authored and Linus Torvalds committed Oct 31, 2005
1 parent 9131dd4 commit ad2c160
Showing 1 changed file with 101 additions and 123 deletions.
224 changes: 101 additions & 123 deletions fs/fat/dir.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -222,6 +222,80 @@ fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size,
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.
Expand Down Expand Up @@ -259,65 +333,16 @@ int fat_search_long(struct inode *inode, const unsigned char *name,
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 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))
int status = fat_parse_long(inode, &cpos, &bh, &de,
&unicode, &nr_slots);
if (status < 0)
return status;
else if (status == PARSE_INVALID)
continue;
if (fat_checksum(de->name) != alias_checksum)
nr_slots = 0;
else if (status == PARSE_NOT_LONGNAME)
goto parse_record;
else if (status == PARSE_EOF)
goto EODir;
}

memcpy(work, de->name, sizeof(de->name));
Expand Down Expand Up @@ -405,8 +430,8 @@ struct fat_ioctl_filldir_callback {
int short_len;
};

static int fat_readdirx(struct inode *inode, struct file *filp, void *dirent,
filldir_t filldir, int short_only, int both)
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);
Expand Down Expand Up @@ -455,9 +480,10 @@ static int fat_readdirx(struct inode *inode, struct file *filp, void *dirent,

bh = NULL;
GetNew:
long_slots = 0;
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)
Expand All @@ -472,66 +498,18 @@ static int fat_readdirx(struct inode *inode, struct file *filp, void *dirent,
}

if (isvfat && de->attr == ATTR_EXT) {
struct msdos_dir_slot *ds;
unsigned char id;
unsigned char slot;
unsigned char slots;
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) */
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;
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;
if (fat_checksum(de->name) != alias_checksum)
long_slots = 0;
else if (status == PARSE_NOT_LONGNAME)
goto parse_record;
else if (status == PARSE_EOF)
goto EODir;
}

if (sbi->options.dotsOK) {
Expand Down Expand Up @@ -665,7 +643,7 @@ static int fat_readdirx(struct inode *inode, struct file *filp, void *dirent,
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);
return __fat_readdir(inode, filp, dirent, filldir, 0, 0);
}

static int fat_ioctl_filldir(void *__buf, const char *name, int name_len,
Expand Down Expand Up @@ -754,8 +732,8 @@ static int fat_dir_ioctl(struct inode * inode, struct file * filp,
down(&inode->i_sem);
ret = -ENOENT;
if (!IS_DEADDIR(inode)) {
ret = fat_readdirx(inode, filp, &buf, fat_ioctl_filldir,
short_only, both);
ret = __fat_readdir(inode, filp, &buf, fat_ioctl_filldir,
short_only, both);
}
up(&inode->i_sem);
if (ret >= 0)
Expand Down

0 comments on commit ad2c160

Please sign in to comment.