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fat: small optimization to __fat_readdir() 

This removes unnecessary parsing for directory entries.

If short_only, we don't need to parse longname.  And if !both and it found
the longname, we don't need shortname.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
OGAWA Hirofumi 2008-07-25 01:46:44 -07:00 committed by Linus Torvalds
parent 98a1516004
commit dcd8c53f13
1 changed files with 39 additions and 32 deletions
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71
fs/fat/dir.c
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@ -481,11 +481,11 @@ static int __fat_readdir(struct inode *inode, struct file *filp, void *dirent,
unsigned short opt_shortname = sbi->options.shortname;
int isvfat = sbi->options.isvfat;
int nocase = sbi->options.nocase;
const char *fill_name;
const char *fill_name = NULL;
unsigned long inum;
unsigned long lpos, dummy, *furrfu = &lpos;
loff_t cpos;
int chi, chl, i, i2, j, last, last_u, dotoffset = 0, fill_len;
int chi, chl, i, i2, j, last, last_u, dotoffset = 0, fill_len = 0;
int ret = 0;
lock_super(sb);
@ -516,8 +516,11 @@ get_new:
goto end_of_dir;
parse_record:
nr_slots = 0;
/* Check for long filename entry */
if (isvfat) {
/*
* Check for long filename entry, but if short_only, we don't
* need to parse long filename.
*/
if (isvfat && !short_only) {
if (de->name[0] == DELETED_FLAG)
goto record_end;
if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
@ -542,6 +545,18 @@ parse_record:
goto parse_record;
else if (status == PARSE_EOF)
goto end_of_dir;
if (nr_slots) {
void *longname = unicode + FAT_MAX_UNI_CHARS;
int size = PATH_MAX - FAT_MAX_UNI_SIZE;
int len = fat_uni_to_x8(sbi, unicode, longname, size);
fill_name = longname;
fill_len = len;
/* !both && !short_only, so we don't need shortname. */
if (!both)
goto start_filldir;
}
}
if (sbi->options.dotsOK) {
@ -608,6 +623,26 @@ parse_record:
i = last + dotoffset;
j = last_u;
if (isvfat) {
bufuname[j] = 0x0000;
i = fat_uni_to_x8(sbi, bufuname, bufname, sizeof(bufname));
}
if (nr_slots) {
/* hack for fat_ioctl_filldir() */
struct fat_ioctl_filldir_callback *p = dirent;
p->longname = fill_name;
p->long_len = fill_len;
p->shortname = bufname;
p->short_len = i;
fill_name = NULL;
fill_len = 0;
} else {
fill_name = bufname;
fill_len = i;
}
start_filldir:
lpos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME))
inum = inode->i_ino;
@ -623,34 +658,6 @@ parse_record:
inum = iunique(sb, MSDOS_ROOT_INO);
}
if (isvfat) {
bufuname[j] = 0x0000;
i = fat_uni_to_x8(sbi, bufuname, bufname, sizeof(bufname));
}
fill_name = bufname;
fill_len = i;
if (!short_only && nr_slots) {
void *longname = unicode + FAT_MAX_UNI_CHARS;
int long_len, size = PATH_MAX - FAT_MAX_UNI_SIZE;
long_len = fat_uni_to_x8(sbi, unicode, longname, size);
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 fill_failed;