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linux/fs/hpfs/map.c
Mikulas Patocka 275f495dbe hpfs: implement prefetch to improve performance 
This patch implements prefetch to improve performance.  It helps mostly
when scanning the bitmaps to calculate free space.

Signed-off-by: Mikulas Patocka <mpatocka@artax.karlin.mff.cuni.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-04 11:22:46 -07:00

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9.0 KiB
C
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/*
* linux/fs/hpfs/map.c
*
* Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
*
* mapping structures to memory with some minimal checks
*/
#include "hpfs_fn.h"
__le32 *hpfs_map_dnode_bitmap(struct super_block *s, struct quad_buffer_head *qbh)
{
return hpfs_map_4sectors(s, hpfs_sb(s)->sb_dmap, qbh, 0);
}
__le32 *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block,
struct quad_buffer_head *qbh, char *id)
{
secno sec;
__le32 *ret;
unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
if (hpfs_sb(s)->sb_chk) if (bmp_block >= n_bands) {
hpfs_error(s, "hpfs_map_bitmap called with bad parameter: %08x at %s", bmp_block, id);
return NULL;
}
sec = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]);
if (!sec || sec > hpfs_sb(s)->sb_fs_size-4) {
hpfs_error(s, "invalid bitmap block pointer %08x -> %08x at %s", bmp_block, sec, id);
return NULL;
}
ret = hpfs_map_4sectors(s, sec, qbh, 4);
if (ret) hpfs_prefetch_bitmap(s, bmp_block + 1);
return ret;
}
void hpfs_prefetch_bitmap(struct super_block *s, unsigned bmp_block)
{
unsigned to_prefetch, next_prefetch;
unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
if (unlikely(bmp_block >= n_bands))
return;
to_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]);
if (unlikely(bmp_block + 1 >= n_bands))
next_prefetch = 0;
else
next_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block + 1]);
hpfs_prefetch_sectors(s, to_prefetch, 4 + 4 * (to_prefetch + 4 == next_prefetch));
}
/*
* Load first code page into kernel memory, return pointer to 256-byte array,
* first 128 bytes are uppercasing table for chars 128-255, next 128 bytes are
* lowercasing table
*/
unsigned char *hpfs_load_code_page(struct super_block *s, secno cps)
{
struct buffer_head *bh;
secno cpds;
unsigned cpi;
unsigned char *ptr;
unsigned char *cp_table;
int i;
struct code_page_data *cpd;
struct code_page_directory *cp = hpfs_map_sector(s, cps, &bh, 0);
if (!cp) return NULL;
if (le32_to_cpu(cp->magic) != CP_DIR_MAGIC) {
printk("HPFS: Code page directory magic doesn't match (magic = %08x)\n", le32_to_cpu(cp->magic));
brelse(bh);
return NULL;
}
if (!le32_to_cpu(cp->n_code_pages)) {
printk("HPFS: n_code_pages == 0\n");
brelse(bh);
return NULL;
}
cpds = le32_to_cpu(cp->array[0].code_page_data);
cpi = le16_to_cpu(cp->array[0].index);
brelse(bh);
if (cpi >= 3) {
printk("HPFS: Code page index out of array\n");
return NULL;
}
if (!(cpd = hpfs_map_sector(s, cpds, &bh, 0))) return NULL;
if (le16_to_cpu(cpd->offs[cpi]) > 0x178) {
printk("HPFS: Code page index out of sector\n");
brelse(bh);
return NULL;
}
ptr = (unsigned char *)cpd + le16_to_cpu(cpd->offs[cpi]) + 6;
if (!(cp_table = kmalloc(256, GFP_KERNEL))) {
printk("HPFS: out of memory for code page table\n");
brelse(bh);
return NULL;
}
memcpy(cp_table, ptr, 128);
brelse(bh);
/* Try to build lowercasing table from uppercasing one */
for (i=128; i<256; i++) cp_table[i]=i;
for (i=128; i<256; i++) if (cp_table[i-128]!=i && cp_table[i-128]>=128)
cp_table[cp_table[i-128]] = i;
return cp_table;
}
__le32 *hpfs_load_bitmap_directory(struct super_block *s, secno bmp)
{
struct buffer_head *bh;
int n = (hpfs_sb(s)->sb_fs_size + 0x200000 - 1) >> 21;
int i;
__le32 *b;
if (!(b = kmalloc(n * 512, GFP_KERNEL))) {
printk("HPFS: can't allocate memory for bitmap directory\n");
return NULL;
}
for (i=0;i<n;i++) {
__le32 *d = hpfs_map_sector(s, bmp+i, &bh, n - i - 1);
if (!d) {
kfree(b);
return NULL;
}
memcpy((char *)b + 512 * i, d, 512);
brelse(bh);
}
return b;
}
/*
* Load fnode to memory
*/
struct fnode *hpfs_map_fnode(struct super_block *s, ino_t ino, struct buffer_head **bhp)
{
struct fnode *fnode;
if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ino, 1, "fnode")) {
return NULL;
}
if ((fnode = hpfs_map_sector(s, ino, bhp, FNODE_RD_AHEAD))) {
if (hpfs_sb(s)->sb_chk) {
struct extended_attribute *ea;
struct extended_attribute *ea_end;
if (le32_to_cpu(fnode->magic) != FNODE_MAGIC) {
hpfs_error(s, "bad magic on fnode %08lx",
(unsigned long)ino);
goto bail;
}
if (!fnode_is_dir(fnode)) {
if ((unsigned)fnode->btree.n_used_nodes + (unsigned)fnode->btree.n_free_nodes !=
(bp_internal(&fnode->btree) ? 12 : 8)) {
hpfs_error(s,
"bad number of nodes in fnode %08lx",
(unsigned long)ino);
goto bail;
}
if (le16_to_cpu(fnode->btree.first_free) !=
8 + fnode->btree.n_used_nodes * (bp_internal(&fnode->btree) ? 8 : 12)) {
hpfs_error(s,
"bad first_free pointer in fnode %08lx",
(unsigned long)ino);
goto bail;
}
}
if (le16_to_cpu(fnode->ea_size_s) && (le16_to_cpu(fnode->ea_offs) < 0xc4 ||
le16_to_cpu(fnode->ea_offs) + le16_to_cpu(fnode->acl_size_s) + le16_to_cpu(fnode->ea_size_s) > 0x200)) {
hpfs_error(s,
"bad EA info in fnode %08lx: ea_offs == %04x ea_size_s == %04x",
(unsigned long)ino,
le16_to_cpu(fnode->ea_offs), le16_to_cpu(fnode->ea_size_s));
goto bail;
}
ea = fnode_ea(fnode);
ea_end = fnode_end_ea(fnode);
while (ea != ea_end) {
if (ea > ea_end) {
hpfs_error(s, "bad EA in fnode %08lx",
(unsigned long)ino);
goto bail;
}
ea = next_ea(ea);
}
}
}
return fnode;
bail:
brelse(*bhp);
return NULL;
}
struct anode *hpfs_map_anode(struct super_block *s, anode_secno ano, struct buffer_head **bhp)
{
struct anode *anode;
if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ano, 1, "anode")) return NULL;
if ((anode = hpfs_map_sector(s, ano, bhp, ANODE_RD_AHEAD)))
if (hpfs_sb(s)->sb_chk) {
if (le32_to_cpu(anode->magic) != ANODE_MAGIC) {
hpfs_error(s, "bad magic on anode %08x", ano);
goto bail;
}
if (le32_to_cpu(anode->self) != ano) {
hpfs_error(s, "self pointer invalid on anode %08x", ano);
goto bail;
}
if ((unsigned)anode->btree.n_used_nodes + (unsigned)anode->btree.n_free_nodes !=
(bp_internal(&anode->btree) ? 60 : 40)) {
hpfs_error(s, "bad number of nodes in anode %08x", ano);
goto bail;
}
if (le16_to_cpu(anode->btree.first_free) !=
8 + anode->btree.n_used_nodes * (bp_internal(&anode->btree) ? 8 : 12)) {
hpfs_error(s, "bad first_free pointer in anode %08x", ano);
goto bail;
}
}
return anode;
bail:
brelse(*bhp);
return NULL;
}
/*
* Load dnode to memory and do some checks
*/
struct dnode *hpfs_map_dnode(struct super_block *s, unsigned secno,
struct quad_buffer_head *qbh)
{
struct dnode *dnode;
if (hpfs_sb(s)->sb_chk) {
if (hpfs_chk_sectors(s, secno, 4, "dnode")) return NULL;
if (secno & 3) {
hpfs_error(s, "dnode %08x not byte-aligned", secno);
return NULL;
}
}
if ((dnode = hpfs_map_4sectors(s, secno, qbh, DNODE_RD_AHEAD)))
if (hpfs_sb(s)->sb_chk) {
unsigned p, pp = 0;
unsigned char *d = (unsigned char *)dnode;
int b = 0;
if (le32_to_cpu(dnode->magic) != DNODE_MAGIC) {
hpfs_error(s, "bad magic on dnode %08x", secno);
goto bail;
}
if (le32_to_cpu(dnode->self) != secno)
hpfs_error(s, "bad self pointer on dnode %08x self = %08x", secno, le32_to_cpu(dnode->self));
/* Check dirents - bad dirents would cause infinite
loops or shooting to memory */
if (le32_to_cpu(dnode->first_free) > 2048) {
hpfs_error(s, "dnode %08x has first_free == %08x", secno, le32_to_cpu(dnode->first_free));
goto bail;
}
for (p = 20; p < le32_to_cpu(dnode->first_free); p += d[p] + (d[p+1] << 8)) {
struct hpfs_dirent *de = (struct hpfs_dirent *)((char *)dnode + p);
if (le16_to_cpu(de->length) > 292 || (le16_to_cpu(de->length) < 32) || (le16_to_cpu(de->length) & 3) || p + le16_to_cpu(de->length) > 2048) {
hpfs_error(s, "bad dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
goto bail;
}
if (((31 + de->namelen + de->down*4 + 3) & ~3) != le16_to_cpu(de->length)) {
if (((31 + de->namelen + de->down*4 + 3) & ~3) < le16_to_cpu(de->length) && s->s_flags & MS_RDONLY) goto ok;
hpfs_error(s, "namelen does not match dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
goto bail;
}
ok:
if (hpfs_sb(s)->sb_chk >= 2) b |= 1 << de->down;
if (de->down) if (de_down_pointer(de) < 0x10) {
hpfs_error(s, "bad down pointer in dnode %08x, dirent %03x, last %03x", secno, p, pp);
goto bail;
}
pp = p;
}
if (p != le32_to_cpu(dnode->first_free)) {
hpfs_error(s, "size on last dirent does not match first_free; dnode %08x", secno);
goto bail;
}
if (d[pp + 30] != 1 || d[pp + 31] != 255) {
hpfs_error(s, "dnode %08x does not end with \\377 entry", secno);
goto bail;
}
if (b == 3) printk("HPFS: warning: unbalanced dnode tree, dnode %08x; see hpfs.txt 4 more info\n", secno);
}
return dnode;
bail:
hpfs_brelse4(qbh);
return NULL;
}
dnode_secno hpfs_fnode_dno(struct super_block *s, ino_t ino)
{
struct buffer_head *bh;
struct fnode *fnode;
dnode_secno dno;
fnode = hpfs_map_fnode(s, ino, &bh);
if (!fnode)
return 0;
dno = le32_to_cpu(fnode->u.external[0].disk_secno);
brelse(bh);
return dno;
}
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