From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
This rewrites the cache stuff for file allocation table (FAT).
This cache stocks the more pieces of FAT-chain by counting the number
of contiguous data blocks. And if cache hit, since a block number can
calculate without looking FAT-chain up, fat_get_block() become more
fast.
But if data blocks was fragmenting, unfortunately this cache is unuseful.
read from block device
[1st]# time dd if=/dev/hda6 of=/dev/null bs=1M count=2048
2147483648 bytes transferred in 229.524189 seconds (9356241 bytes/sec)
real 3m49.557s, user 0m0.026s, sys 1m20.414s
[2nd]# time dd if=/dev/hda6 of=/dev/null bs=1M count=2048
2147483648 bytes transferred in 229.539358 seconds (9355623 bytes/sec)
real 3m49.647s, user 0m0.036s, sys 1m20.144s
read from full contiguous file with this patch
[1st]# time dd if=data of=/dev/null bs=1M count=2048
2147483648 bytes transferred in 337.959477 seconds (6354264 bytes/sec)
real 5m37.970s, user 0m0.031s, sys 1m21.915s
[2nd]# time dd if=data of=/dev/null bs=1M count=2048
2147483648 bytes transferred in 225.401699 seconds (9527362 bytes/sec)
real 3m45.476s, user 0m0.027s, sys 1m19.286s
read from full fragmented file with this patch
[1st]# time dd if=data of=/dev/null bs=1M count=2048
2147483647 bytes transferred in 1146.529081 seconds (1873030 bytes/sec)
real 19m6.538s, user 0m0.020s, sys 1m32.774s
[2nd]# time dd if=data of=/dev/null bs=1M count=2048
2147483647 bytes transferred in 1045.084822 seconds (2054841 bytes/sec)
real 17m25.152s, user 0m0.022s, sys 1m34.801s
read from full contiguous file without this patch
[1st]# time dd if=data of=/dev/null bs=1M count=2048
2147483648 bytes transferred in 348.144707 seconds (6168365 bytes/sec)
real 5m48.169s, user 0m0.019s, sys 1m29.962s
[2nd]# time dd if=data of=/dev/null bs=1M count=2048
2147483648 bytes transferred in 324.017361 seconds (6627681 bytes/sec)
real 5m24.038s, user 0m0.023s, sys 1m20.602s
read from full fragmented file without this patch
[1st]# time dd if=data of=/dev/null bs=1M count=2048
2147483647 bytes transferred in 1156.845693 seconds (1856327 bytes/sec)
real 19m16.855s, user 0m0.031s, sys 1m32.172s
[2nd]# time dd if=data of=/dev/null bs=1M count=2048
2147483647 bytes transferred in 1066.518713 seconds (2013545 bytes/sec)
real 17m46.526s, user 0m0.023s, sys 1m33.630s
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/fs/fat/cache.c | 370 ++++++++++++++++++++----------------
25-akpm/fs/fat/fatfs_syms.c | 7
25-akpm/fs/fat/inode.c | 6
25-akpm/fs/fat/misc.c | 2
25-akpm/include/linux/msdos_fs.h | 2
25-akpm/include/linux/msdos_fs_i.h | 5
25-akpm/include/linux/msdos_fs_sb.h | 10
7 files changed, 226 insertions(+), 176 deletions(-)
diff -puN fs/fat/cache.c~fat-rewrite-the-cache-for-file-allocation-table-lookup fs/fat/cache.c
--- 25/fs/fat/cache.c~fat-rewrite-the-cache-for-file-allocation-table-lookup 2004-09-11 17:07:32.021073096 -0700
+++ 25-akpm/fs/fat/cache.c 2004-09-11 17:07:32.035070968 -0700
@@ -12,6 +12,204 @@
#include <linux/msdos_fs.h>
#include <linux/buffer_head.h>
+#if 0
+#define debug_pr(fmt, args...) printk(fmt, ##args)
+#else
+#define debug_pr(fmt, args...)
+#endif
+
+/* 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. */
+};
+
+static inline int fat_max_cache(struct inode *inode)
+{
+ return FAT_MAX_CACHE;
+}
+
+static kmem_cache_t *fat_cache_cachep;
+
+static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags)
+{
+ struct fat_cache *cache = (struct fat_cache *)foo;
+
+ if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
+ SLAB_CTOR_CONSTRUCTOR)
+ 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,
+ init_once, NULL);
+ if (fat_cache_cachep == NULL)
+ return -ENOMEM;
+ return 0;
+}
+
+void __exit fat_cache_destroy(void)
+{
+ if (kmem_cache_destroy(fat_cache_cachep))
+ printk(KERN_INFO "fat_cache: not all structures were freed\n");
+}
+
+static inline struct fat_cache *fat_cache_alloc(struct inode *inode)
+{
+ return kmem_cache_alloc(fat_cache_cachep, SLAB_KERNEL);
+}
+
+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 *cache,
+ int *cached_fclus, int *cached_dclus)
+{
+ static struct fat_cache nohit = { .fcluster = 0, };
+
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+ struct fat_cache *hit = &nohit, *p;
+ int offset = -1;
+
+ spin_lock(&sbi->cache_lock);
+ debug_pr("FAT: %s, fclus %d", __FUNCTION__, fclus);
+ list_for_each_entry(p, &MSDOS_I(inode)->cache_lru, cache_list) {
+ if (p->fcluster <= fclus && hit->fcluster < p->fcluster) {
+ hit = p;
+ debug_pr(", fclus %d, dclus %d, cont %d",
+ p->fcluster, p->dcluster, p->nr_contig);
+ if ((hit->fcluster + hit->nr_contig) < fclus) {
+ offset = hit->nr_contig;
+ debug_pr(" (off %d, hit)", offset);
+ } else {
+ offset = fclus - hit->fcluster;
+ debug_pr(" (off %d, full hit)", offset);
+ break;
+ }
+ }
+ }
+ if (hit != &nohit) {
+ fat_cache_update_lru(inode, hit);
+ *cache = *hit;
+ *cached_fclus = cache->fcluster + offset;
+ *cached_dclus = cache->dcluster + offset;
+ }
+ debug_pr("\n");
+ spin_unlock(&sbi->cache_lock);
+
+ return offset;
+}
+
+static struct fat_cache *fat_cache_merge(struct inode *inode,
+ struct fat_cache *new)
+{
+ struct fat_cache *p, *hit = NULL;
+
+ list_for_each_entry(p, &MSDOS_I(inode)->cache_lru, cache_list) {
+ if (p->fcluster == new->fcluster) {
+ BUG_ON(p->dcluster != new->dcluster);
+ debug_pr("FAT: %s: merged fclus %d, dclus %d, "
+ "cur cont %d => new cont %d\n", __FUNCTION__,
+ p->fcluster, p->dcluster, p->nr_contig,
+ new->nr_contig);
+ if (new->nr_contig > p->nr_contig)
+ p->nr_contig = new->nr_contig;
+ hit = p;
+ break;
+ }
+ }
+ return hit;
+}
+
+static void fat_cache_add(struct inode *inode, struct fat_cache *new)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+ struct fat_cache *cache, *tmp;
+
+ debug_pr("FAT: %s: fclus %d, dclus %d, cont %d\n", __FUNCTION__,
+ new->fcluster, new->dcluster, new->nr_contig);
+
+ if (new->fcluster == -1) /* dummy cache */
+ return;
+
+ spin_lock(&sbi->cache_lock);
+ 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(&sbi->cache_lock);
+
+ tmp = fat_cache_alloc(inode);
+ spin_lock(&sbi->cache_lock);
+ cache = fat_cache_merge(inode, new);
+ if (cache != NULL) {
+ MSDOS_I(inode)->nr_caches--;
+ fat_cache_free(tmp);
+ goto out;
+ }
+ 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:
+ fat_cache_update_lru(inode, cache);
+
+ debug_pr("FAT: ");
+ list_for_each_entry(cache, &MSDOS_I(inode)->cache_lru, cache_list) {
+ debug_pr("(fclus %d, dclus %d, cont %d), ",
+ cache->fcluster, cache->dcluster, cache->nr_contig);
+ }
+ debug_pr("\n");
+ spin_unlock(&sbi->cache_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);
+ MSDOS_I(inode)->nr_caches--;
+ fat_cache_free(cache);
+ }
+ debug_pr("FAT: %s\n", __FUNCTION__);
+}
+
+void fat_cache_inval_inode(struct inode *inode)
+{
+ spin_lock(&MSDOS_SB(inode->i_sb)->cache_lock);
+ __fat_cache_inval_inode(inode);
+ spin_unlock(&MSDOS_SB(inode->i_sb)->cache_lock);
+}
+
int __fat_access(struct super_block *sb, int nr, int new_value)
{
struct msdos_sb_info *sbi = MSDOS_SB(sb);
@@ -130,170 +328,24 @@ out:
return next;
}
-void fat_cache_init(struct super_block *sb)
-{
- struct msdos_sb_info *sbi = MSDOS_SB(sb);
- int count;
-
- spin_lock_init(&sbi->cache_lock);
-
- for (count = 0; count < FAT_CACHE_NR - 1; count++) {
- sbi->cache_array[count].start_cluster = 0;
- sbi->cache_array[count].next = &sbi->cache_array[count + 1];
- }
- sbi->cache_array[count].start_cluster = 0;
- sbi->cache_array[count].next = NULL;
- sbi->cache = sbi->cache_array;
-}
-
-static void
-fat_cache_lookup(struct inode *inode, int cluster, int *f_clu, int *d_clu)
-{
- struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
- struct fat_cache *walk;
- int first;
-
- BUG_ON(cluster == 0);
-
- first = MSDOS_I(inode)->i_start;
- if (!first)
- return;
-
- spin_lock(&sbi->cache_lock);
-
- if (MSDOS_I(inode)->disk_cluster &&
- MSDOS_I(inode)->file_cluster <= cluster) {
- *d_clu = MSDOS_I(inode)->disk_cluster;
- *f_clu = MSDOS_I(inode)->file_cluster;
- }
-
- for (walk = sbi->cache; walk; walk = walk->next) {
- if (walk->start_cluster == first
- && walk->file_cluster <= cluster
- && walk->file_cluster > *f_clu) {
- *d_clu = walk->disk_cluster;
- *f_clu = walk->file_cluster;
-#ifdef DEBUG
- printk("cache hit: %d (%d)\n", *f_clu, *d_clu);
-#endif
- if (*f_clu == cluster)
- goto out;
- }
- }
-#ifdef DEBUG
- printk("cache miss\n");
-#endif
-out:
- spin_unlock(&sbi->cache_lock);
-}
-
-#ifdef DEBUG
-static void list_cache(struct super_block *sb)
-{
- struct msdos_sb_info *sbi = MSDOS_SB(sb);
- struct fat_cache *walk;
-
- for (walk = sbi->cache; walk; walk = walk->next) {
- if (walk->start_cluster)
- printk("<%s,%d>(%d,%d) ", sb->s_id,
- walk->start_cluster, walk->file_cluster,
- walk->disk_cluster);
- else
- printk("-- ");
- }
- printk("\n");
-}
-#endif
-
-/*
- * 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)
+static inline int cache_contiguous(struct fat_cache *cache, int dclus)
{
- struct fat_cache *walk;
- int first = MSDOS_I(inode)->i_start;
- MSDOS_I(inode)->file_cluster = MSDOS_I(inode)->disk_cluster = 0;
- for (walk = MSDOS_SB(inode->i_sb)->cache; walk; walk = walk->next)
- if (walk->start_cluster == first)
- walk->start_cluster = 0;
+ cache->nr_contig++;
+ return ((cache->dcluster + cache->nr_contig) == dclus);
}
-void fat_cache_inval_inode(struct inode *inode)
+static inline void cache_init(struct fat_cache *cache, int fclus, int dclus)
{
- struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
- spin_lock(&sbi->cache_lock);
- __fat_cache_inval_inode(inode);
- spin_unlock(&sbi->cache_lock);
-}
-
-void fat_cache_add(struct inode *inode, int f_clu, int d_clu)
-{
- struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
- struct fat_cache *walk, *last;
- int first, prev_f_clu, prev_d_clu;
-
- if (f_clu == 0)
- return;
- first = MSDOS_I(inode)->i_start;
- if (!first)
- return;
-
- last = NULL;
- spin_lock(&sbi->cache_lock);
-
- if (MSDOS_I(inode)->file_cluster == f_clu)
- goto out;
- else {
- prev_f_clu = MSDOS_I(inode)->file_cluster;
- prev_d_clu = MSDOS_I(inode)->disk_cluster;
- MSDOS_I(inode)->file_cluster = f_clu;
- MSDOS_I(inode)->disk_cluster = d_clu;
- if (prev_f_clu == 0)
- goto out;
- f_clu = prev_f_clu;
- d_clu = prev_d_clu;
- }
-
- for (walk = sbi->cache; walk->next; walk = (last = walk)->next) {
- if (walk->start_cluster == first &&
- walk->file_cluster == f_clu) {
- if (walk->disk_cluster != d_clu) {
- printk(KERN_ERR "FAT: cache corruption "
- "(i_pos %lld)\n", MSDOS_I(inode)->i_pos);
- __fat_cache_inval_inode(inode);
- goto out;
- }
- if (last == NULL)
- goto out;
-
- /* update LRU */
- last->next = walk->next;
- walk->next = sbi->cache;
- sbi->cache = walk;
-#ifdef DEBUG
- list_cache();
-#endif
- goto out;
- }
- }
- walk->start_cluster = first;
- walk->file_cluster = f_clu;
- walk->disk_cluster = d_clu;
- last->next = NULL;
- walk->next = sbi->cache;
- sbi->cache = walk;
-#ifdef DEBUG
- list_cache();
-#endif
-out:
- spin_unlock(&sbi->cache_lock);
+ cache->fcluster = fclus;
+ cache->dcluster = dclus;
+ cache->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_cache cache;
int nr;
BUG_ON(MSDOS_I(inode)->i_start == 0);
@@ -303,7 +355,9 @@ int fat_get_cluster(struct inode *inode,
if (cluster == 0)
return 0;
- fat_cache_lookup(inode, cluster, fclus, dclus);
+ if (fat_cache_lookup(inode, cluster, &cache, fclus, dclus) < 0)
+ cache_init(&cache, -1, -1); /* dummy, always not contiguous */
+
while (*fclus < cluster) {
/* prevent the infinite loop of cluster chain */
if (*fclus > limit) {
@@ -322,13 +376,15 @@ int fat_get_cluster(struct inode *inode,
MSDOS_I(inode)->i_pos);
return -EIO;
} else if (nr == FAT_ENT_EOF) {
- fat_cache_add(inode, *fclus, *dclus);
+ fat_cache_add(inode, &cache);
return FAT_ENT_EOF;
}
(*fclus)++;
*dclus = nr;
+ if (!cache_contiguous(&cache, *dclus))
+ cache_init(&cache, *fclus, *dclus);
}
- fat_cache_add(inode, *fclus, *dclus);
+ fat_cache_add(inode, &cache);
return 0;
}
diff -puN fs/fat/fatfs_syms.c~fat-rewrite-the-cache-for-file-allocation-table-lookup fs/fat/fatfs_syms.c
--- 25/fs/fat/fatfs_syms.c~fat-rewrite-the-cache-for-file-allocation-table-lookup 2004-09-11 17:07:32.022072944 -0700
+++ 25-akpm/fs/fat/fatfs_syms.c 2004-09-11 17:07:32.035070968 -0700
@@ -24,16 +24,23 @@ EXPORT_SYMBOL(fat_scan);
EXPORT_SYMBOL(fat_add_entries);
EXPORT_SYMBOL(fat_dir_empty);
+int __init fat_cache_init(void);
+void __exit fat_cache_destroy(void);
int __init fat_init_inodecache(void);
void __exit fat_destroy_inodecache(void);
static int __init init_fat_fs(void)
{
+ int ret;
fat_hash_init();
+ ret = fat_cache_init();
+ if (ret < 0)
+ return ret;
return fat_init_inodecache();
}
static void __exit exit_fat_fs(void)
{
+ fat_cache_destroy();
fat_destroy_inodecache();
}
diff -puN fs/fat/inode.c~fat-rewrite-the-cache-for-file-allocation-table-lookup fs/fat/inode.c
--- 25/fs/fat/inode.c~fat-rewrite-the-cache-for-file-allocation-table-lookup 2004-09-11 17:07:32.024072640 -0700
+++ 25-akpm/fs/fat/inode.c 2004-09-11 17:07:32.037070664 -0700
@@ -533,7 +533,6 @@ static int fat_read_root(struct inode *i
struct msdos_sb_info *sbi = MSDOS_SB(sb);
int error;
- MSDOS_I(inode)->file_cluster = MSDOS_I(inode)->disk_cluster = 0;
MSDOS_I(inode)->i_pos = 0;
inode->i_uid = sbi->options.fs_uid;
inode->i_gid = sbi->options.fs_gid;
@@ -736,6 +735,8 @@ static void init_once(void * foo, kmem_c
if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
SLAB_CTOR_CONSTRUCTOR) {
+ ei->nr_caches = 0;
+ INIT_LIST_HEAD(&ei->cache_lru);
INIT_HLIST_NODE(&ei->i_fat_hash);
inode_init_once(&ei->vfs_inode);
}
@@ -819,7 +820,7 @@ int fat_fill_super(struct super_block *s
if (error)
goto out_fail;
- fat_cache_init(sb);
+ spin_lock_init(&MSDOS_SB(sb)->cache_lock);
/* set up enough so that it can read an inode */
init_MUTEX(&sbi->fat_lock);
@@ -1164,7 +1165,6 @@ static int fat_fill_inode(struct inode *
struct msdos_sb_info *sbi = MSDOS_SB(sb);
int error;
- MSDOS_I(inode)->file_cluster = MSDOS_I(inode)->disk_cluster = 0;
MSDOS_I(inode)->i_pos = 0;
inode->i_uid = sbi->options.fs_uid;
inode->i_gid = sbi->options.fs_gid;
diff -puN fs/fat/misc.c~fat-rewrite-the-cache-for-file-allocation-table-lookup fs/fat/misc.c
--- 25/fs/fat/misc.c~fat-rewrite-the-cache-for-file-allocation-table-lookup 2004-09-11 17:07:32.025072488 -0700
+++ 25-akpm/fs/fat/misc.c 2004-09-11 17:07:32.037070664 -0700
@@ -155,7 +155,7 @@ int fat_add_cluster(struct inode *inode)
ret = fat_access(sb, last, new_dclus);
if (ret < 0)
return ret;
- fat_cache_add(inode, new_fclus, new_dclus);
+// fat_cache_add(inode, new_fclus, new_dclus);
} else {
MSDOS_I(inode)->i_start = new_dclus;
MSDOS_I(inode)->i_logstart = new_dclus;
diff -puN include/linux/msdos_fs.h~fat-rewrite-the-cache-for-file-allocation-table-lookup include/linux/msdos_fs.h
--- 25/include/linux/msdos_fs.h~fat-rewrite-the-cache-for-file-allocation-table-lookup 2004-09-11 17:07:32.027072184 -0700
+++ 25-akpm/include/linux/msdos_fs.h 2004-09-11 17:07:32.038070512 -0700
@@ -232,8 +232,6 @@ static inline void fatwchar_to16(__u8 *d
extern int fat_access(struct super_block *sb, int nr, int new_value);
extern int __fat_access(struct super_block *sb, int nr, int new_value);
extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys);
-extern void fat_cache_init(struct super_block *sb);
-extern void fat_cache_add(struct inode *inode, int f_clu, int d_clu);
extern void fat_cache_inval_inode(struct inode *inode);
extern int fat_get_cluster(struct inode *inode, int cluster,
int *fclus, int *dclus);
diff -puN include/linux/msdos_fs_i.h~fat-rewrite-the-cache-for-file-allocation-table-lookup include/linux/msdos_fs_i.h
--- 25/include/linux/msdos_fs_i.h~fat-rewrite-the-cache-for-file-allocation-table-lookup 2004-09-11 17:07:32.028072032 -0700
+++ 25-akpm/include/linux/msdos_fs_i.h 2004-09-11 17:07:32.038070512 -0700
@@ -8,9 +8,8 @@
*/
struct msdos_inode_info {
- /* cache of lastest accessed cluster */
- int file_cluster; /* cluster number in the file. */
- int disk_cluster; /* cluster number on disk. */
+ struct list_head cache_lru;
+ int nr_caches;
loff_t mmu_private;
int i_start; /* first cluster or 0 */
diff -puN include/linux/msdos_fs_sb.h~fat-rewrite-the-cache-for-file-allocation-table-lookup include/linux/msdos_fs_sb.h
--- 25/include/linux/msdos_fs_sb.h~fat-rewrite-the-cache-for-file-allocation-table-lookup 2004-09-11 17:07:32.030071728 -0700
+++ 25-akpm/include/linux/msdos_fs_sb.h 2004-09-11 17:07:32.038070512 -0700
@@ -26,15 +26,6 @@ struct fat_mount_options {
nocase:1; /* Does this need case conversion? 0=need case conversion*/
};
-#define FAT_CACHE_NR 8 /* number of FAT cache */
-
-struct fat_cache {
- int start_cluster; /* first cluster of the chain. */
- int file_cluster; /* cluster number in the file. */
- int disk_cluster; /* cluster number on disk. */
- struct fat_cache *next; /* next cache entry */
-};
-
struct msdos_sb_info {
unsigned short sec_per_clus; /* sectors/cluster */
unsigned short cluster_bits; /* log2(cluster_size) */
@@ -59,7 +50,6 @@ struct msdos_sb_info {
int dir_per_block_bits; /* log2(dir_per_block) */
spinlock_t cache_lock;
- struct fat_cache cache_array[FAT_CACHE_NR], *cache;
};
#endif
_