linux/fs/fat/cache.c
Alexey Dobriyan 51cc50685a SL*B: drop kmem cache argument from constructor
Kmem cache passed to constructor is only needed for constructors that are
themselves multiplexeres.  Nobody uses this "feature", nor does anybody uses
passed kmem cache in non-trivial way, so pass only pointer to object.

Non-trivial places are:
	arch/powerpc/mm/init_64.c
	arch/powerpc/mm/hugetlbpage.c

This is flag day, yes.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Jon Tollefson <kniht@linux.vnet.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Matt Mackall <mpm@selenic.com>
[akpm@linux-foundation.org: fix arch/powerpc/mm/hugetlbpage.c]
[akpm@linux-foundation.org: fix mm/slab.c]
[akpm@linux-foundation.org: fix ubifs]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-26 12:00:07 -07:00

329 lines
8 KiB
C

/*
* linux/fs/fat/cache.c
*
* Written 1992,1993 by Werner Almesberger
*
* Mar 1999. AV. Changed cache, so that it uses the starting cluster instead
* of inode number.
* May 1999. AV. Fixed the bogosity with FAT32 (read "FAT28"). Fscking lusers.
*/
#include <linux/fs.h>
#include <linux/msdos_fs.h>
#include <linux/buffer_head.h>
/* this must be > 0. */
#define FAT_MAX_CACHE 8
struct fat_cache {
struct list_head cache_list;
int nr_contig; /* number of contiguous clusters */
int fcluster; /* cluster number in the file. */
int dcluster; /* cluster number on disk. */
};
struct fat_cache_id {
unsigned int id;
int nr_contig;
int fcluster;
int dcluster;
};
static inline int fat_max_cache(struct inode *inode)
{
return FAT_MAX_CACHE;
}
static struct kmem_cache *fat_cache_cachep;
static void init_once(void *foo)
{
struct fat_cache *cache = (struct fat_cache *)foo;
INIT_LIST_HEAD(&cache->cache_list);
}
int __init fat_cache_init(void)
{
fat_cache_cachep = kmem_cache_create("fat_cache",
sizeof(struct fat_cache),
0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
init_once);
if (fat_cache_cachep == NULL)
return -ENOMEM;
return 0;
}
void fat_cache_destroy(void)
{
kmem_cache_destroy(fat_cache_cachep);
}
static inline struct fat_cache *fat_cache_alloc(struct inode *inode)
{
return kmem_cache_alloc(fat_cache_cachep, GFP_NOFS);
}
static inline void fat_cache_free(struct fat_cache *cache)
{
BUG_ON(!list_empty(&cache->cache_list));
kmem_cache_free(fat_cache_cachep, cache);
}
static inline void fat_cache_update_lru(struct inode *inode,
struct fat_cache *cache)
{
if (MSDOS_I(inode)->cache_lru.next != &cache->cache_list)
list_move(&cache->cache_list, &MSDOS_I(inode)->cache_lru);
}
static int fat_cache_lookup(struct inode *inode, int fclus,
struct fat_cache_id *cid,
int *cached_fclus, int *cached_dclus)
{
static struct fat_cache nohit = { .fcluster = 0, };
struct fat_cache *hit = &nohit, *p;
int offset = -1;
spin_lock(&MSDOS_I(inode)->cache_lru_lock);
list_for_each_entry(p, &MSDOS_I(inode)->cache_lru, cache_list) {
/* Find the cache of "fclus" or nearest cache. */
if (p->fcluster <= fclus && hit->fcluster < p->fcluster) {
hit = p;
if ((hit->fcluster + hit->nr_contig) < fclus) {
offset = hit->nr_contig;
} else {
offset = fclus - hit->fcluster;
break;
}
}
}
if (hit != &nohit) {
fat_cache_update_lru(inode, hit);
cid->id = MSDOS_I(inode)->cache_valid_id;
cid->nr_contig = hit->nr_contig;
cid->fcluster = hit->fcluster;
cid->dcluster = hit->dcluster;
*cached_fclus = cid->fcluster + offset;
*cached_dclus = cid->dcluster + offset;
}
spin_unlock(&MSDOS_I(inode)->cache_lru_lock);
return offset;
}
static struct fat_cache *fat_cache_merge(struct inode *inode,
struct fat_cache_id *new)
{
struct fat_cache *p;
list_for_each_entry(p, &MSDOS_I(inode)->cache_lru, cache_list) {
/* Find the same part as "new" in cluster-chain. */
if (p->fcluster == new->fcluster) {
BUG_ON(p->dcluster != new->dcluster);
if (new->nr_contig > p->nr_contig)
p->nr_contig = new->nr_contig;
return p;
}
}
return NULL;
}
static void fat_cache_add(struct inode *inode, struct fat_cache_id *new)
{
struct fat_cache *cache, *tmp;
if (new->fcluster == -1) /* dummy cache */
return;
spin_lock(&MSDOS_I(inode)->cache_lru_lock);
if (new->id != FAT_CACHE_VALID &&
new->id != MSDOS_I(inode)->cache_valid_id)
goto out; /* this cache was invalidated */
cache = fat_cache_merge(inode, new);
if (cache == NULL) {
if (MSDOS_I(inode)->nr_caches < fat_max_cache(inode)) {
MSDOS_I(inode)->nr_caches++;
spin_unlock(&MSDOS_I(inode)->cache_lru_lock);
tmp = fat_cache_alloc(inode);
spin_lock(&MSDOS_I(inode)->cache_lru_lock);
cache = fat_cache_merge(inode, new);
if (cache != NULL) {
MSDOS_I(inode)->nr_caches--;
fat_cache_free(tmp);
goto out_update_lru;
}
cache = tmp;
} else {
struct list_head *p = MSDOS_I(inode)->cache_lru.prev;
cache = list_entry(p, struct fat_cache, cache_list);
}
cache->fcluster = new->fcluster;
cache->dcluster = new->dcluster;
cache->nr_contig = new->nr_contig;
}
out_update_lru:
fat_cache_update_lru(inode, cache);
out:
spin_unlock(&MSDOS_I(inode)->cache_lru_lock);
}
/*
* Cache invalidation occurs rarely, thus the LRU chain is not updated. It
* fixes itself after a while.
*/
static void __fat_cache_inval_inode(struct inode *inode)
{
struct msdos_inode_info *i = MSDOS_I(inode);
struct fat_cache *cache;
while (!list_empty(&i->cache_lru)) {
cache = list_entry(i->cache_lru.next, struct fat_cache, cache_list);
list_del_init(&cache->cache_list);
i->nr_caches--;
fat_cache_free(cache);
}
/* Update. The copy of caches before this id is discarded. */
i->cache_valid_id++;
if (i->cache_valid_id == FAT_CACHE_VALID)
i->cache_valid_id++;
}
void fat_cache_inval_inode(struct inode *inode)
{
spin_lock(&MSDOS_I(inode)->cache_lru_lock);
__fat_cache_inval_inode(inode);
spin_unlock(&MSDOS_I(inode)->cache_lru_lock);
}
static inline int cache_contiguous(struct fat_cache_id *cid, int dclus)
{
cid->nr_contig++;
return ((cid->dcluster + cid->nr_contig) == dclus);
}
static inline void cache_init(struct fat_cache_id *cid, int fclus, int dclus)
{
cid->id = FAT_CACHE_VALID;
cid->fcluster = fclus;
cid->dcluster = dclus;
cid->nr_contig = 0;
}
int fat_get_cluster(struct inode *inode, int cluster, int *fclus, int *dclus)
{
struct super_block *sb = inode->i_sb;
const int limit = sb->s_maxbytes >> MSDOS_SB(sb)->cluster_bits;
struct fat_entry fatent;
struct fat_cache_id cid;
int nr;
BUG_ON(MSDOS_I(inode)->i_start == 0);
*fclus = 0;
*dclus = MSDOS_I(inode)->i_start;
if (cluster == 0)
return 0;
if (fat_cache_lookup(inode, cluster, &cid, fclus, dclus) < 0) {
/*
* dummy, always not contiguous
* This is reinitialized by cache_init(), later.
*/
cache_init(&cid, -1, -1);
}
fatent_init(&fatent);
while (*fclus < cluster) {
/* prevent the infinite loop of cluster chain */
if (*fclus > limit) {
fat_fs_panic(sb, "%s: detected the cluster chain loop"
" (i_pos %lld)", __func__,
MSDOS_I(inode)->i_pos);
nr = -EIO;
goto out;
}
nr = fat_ent_read(inode, &fatent, *dclus);
if (nr < 0)
goto out;
else if (nr == FAT_ENT_FREE) {
fat_fs_panic(sb, "%s: invalid cluster chain"
" (i_pos %lld)", __func__,
MSDOS_I(inode)->i_pos);
nr = -EIO;
goto out;
} else if (nr == FAT_ENT_EOF) {
fat_cache_add(inode, &cid);
goto out;
}
(*fclus)++;
*dclus = nr;
if (!cache_contiguous(&cid, *dclus))
cache_init(&cid, *fclus, *dclus);
}
nr = 0;
fat_cache_add(inode, &cid);
out:
fatent_brelse(&fatent);
return nr;
}
static int fat_bmap_cluster(struct inode *inode, int cluster)
{
struct super_block *sb = inode->i_sb;
int ret, fclus, dclus;
if (MSDOS_I(inode)->i_start == 0)
return 0;
ret = fat_get_cluster(inode, cluster, &fclus, &dclus);
if (ret < 0)
return ret;
else if (ret == FAT_ENT_EOF) {
fat_fs_panic(sb, "%s: request beyond EOF (i_pos %lld)",
__func__, MSDOS_I(inode)->i_pos);
return -EIO;
}
return dclus;
}
int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
unsigned long *mapped_blocks)
{
struct super_block *sb = inode->i_sb;
struct msdos_sb_info *sbi = MSDOS_SB(sb);
sector_t last_block;
int cluster, offset;
*phys = 0;
*mapped_blocks = 0;
if ((sbi->fat_bits != 32) && (inode->i_ino == MSDOS_ROOT_INO)) {
if (sector < (sbi->dir_entries >> sbi->dir_per_block_bits)) {
*phys = sector + sbi->dir_start;
*mapped_blocks = 1;
}
return 0;
}
last_block = (MSDOS_I(inode)->mmu_private + (sb->s_blocksize - 1))
>> sb->s_blocksize_bits;
if (sector >= last_block)
return 0;
cluster = sector >> (sbi->cluster_bits - sb->s_blocksize_bits);
offset = sector & (sbi->sec_per_clus - 1);
cluster = fat_bmap_cluster(inode, cluster);
if (cluster < 0)
return cluster;
else if (cluster) {
*phys = fat_clus_to_blknr(sbi, cluster) + offset;
*mapped_blocks = sbi->sec_per_clus - offset;
if (*mapped_blocks > last_block - sector)
*mapped_blocks = last_block - sector;
}
return 0;
}