#include <linux/msdos_fs.h>
#include <linux/buffer_head.h>
-int __fat_access(struct super_block *sb, int nr, int new_value)
+/* 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)
{
- struct msdos_sb_info *sbi = MSDOS_SB(sb);
- struct buffer_head *bh, *bh2, *c_bh, *c_bh2;
- unsigned char *p_first, *p_last;
- int copy, first, last, next, b;
-
- if (sbi->fat_bits == 32) {
- first = last = nr*4;
- } else if (sbi->fat_bits == 16) {
- first = last = nr*2;
- } else {
- first = nr*3/2;
- last = first+1;
- }
- b = sbi->fat_start + (first >> sb->s_blocksize_bits);
- if (!(bh = sb_bread(sb, b))) {
- printk(KERN_ERR "FAT: bread(block %d) in"
- " fat_access failed\n", b);
- return -EIO;
- }
- if ((first >> sb->s_blocksize_bits) == (last >> sb->s_blocksize_bits)) {
- bh2 = bh;
- } else {
- if (!(bh2 = sb_bread(sb, b + 1))) {
- brelse(bh);
- printk(KERN_ERR "FAT: bread(block %d) in"
- " fat_access failed\n", b + 1);
- return -EIO;
- }
- }
- if (sbi->fat_bits == 32) {
- p_first = p_last = NULL; /* GCC needs that stuff */
- next = CF_LE_L(((__le32 *) bh->b_data)[(first &
- (sb->s_blocksize - 1)) >> 2]);
- /* Fscking Microsoft marketing department. Their "32" is 28. */
- next &= 0x0fffffff;
- } else if (sbi->fat_bits == 16) {
- p_first = p_last = NULL; /* GCC needs that stuff */
- next = CF_LE_W(((__le16 *) bh->b_data)[(first &
- (sb->s_blocksize - 1)) >> 1]);
- } else {
- p_first = &((__u8 *)bh->b_data)[first & (sb->s_blocksize - 1)];
- p_last = &((__u8 *)bh2->b_data)[(first + 1) & (sb->s_blocksize - 1)];
- if (nr & 1)
- next = ((*p_first >> 4) | (*p_last << 4)) & 0xfff;
- else
- next = (*p_first+(*p_last << 8)) & 0xfff;
- }
- if (new_value != -1) {
- if (sbi->fat_bits == 32) {
- ((__le32 *)bh->b_data)[(first & (sb->s_blocksize - 1)) >> 2]
- = CT_LE_L(new_value);
- } else if (sbi->fat_bits == 16) {
- ((__le16 *)bh->b_data)[(first & (sb->s_blocksize - 1)) >> 1]
- = CT_LE_W(new_value);
- } else {
- if (nr & 1) {
- *p_first = (*p_first & 0xf) | (new_value << 4);
- *p_last = new_value >> 4;
- }
- else {
- *p_first = new_value & 0xff;
- *p_last = (*p_last & 0xf0) | (new_value >> 8);
- }
- mark_buffer_dirty(bh2);
- }
- mark_buffer_dirty(bh);
- for (copy = 1; copy < sbi->fats; copy++) {
- b = sbi->fat_start + (first >> sb->s_blocksize_bits)
- + sbi->fat_length * copy;
- if (!(c_bh = sb_bread(sb, b)))
- break;
- if (bh != bh2) {
- if (!(c_bh2 = sb_bread(sb, b+1))) {
- brelse(c_bh);
- break;
- }
- memcpy(c_bh2->b_data, bh2->b_data, sb->s_blocksize);
- mark_buffer_dirty(c_bh2);
- brelse(c_bh2);
- }
- memcpy(c_bh->b_data, bh->b_data, sb->s_blocksize);
- mark_buffer_dirty(c_bh);
- brelse(c_bh);
- }
- }
- brelse(bh);
- if (bh != bh2)
- brelse(bh2);
- return next;
+ return FAT_MAX_CACHE;
}
-/*
- * Returns the this'th FAT entry, -1 if it is an end-of-file entry. If
- * new_value is != -1, that FAT entry is replaced by it.
- */
-int fat_access(struct super_block *sb, int nr, int new_value)
+static struct kmem_cache *fat_cache_cachep;
+
+static void init_once(void *foo, struct kmem_cache *cachep, unsigned long flags)
{
- int next;
+ struct fat_cache *cache = (struct fat_cache *)foo;
- next = -EIO;
- if (nr < 2 || MSDOS_SB(sb)->clusters + 2 <= nr) {
- fat_fs_panic(sb, "invalid access to FAT (entry 0x%08x)", nr);
- goto out;
- }
- if (new_value == FAT_ENT_EOF)
- new_value = EOF_FAT(sb);
-
- next = __fat_access(sb, nr, new_value);
- if (next < 0)
- goto out;
- if (next >= BAD_FAT(sb))
- next = FAT_ENT_EOF;
-out:
- return next;
+ if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
+ SLAB_CTOR_CONSTRUCTOR)
+ INIT_LIST_HEAD(&cache->cache_list);
}
-void fat_cache_init(struct super_block *sb)
+int __init fat_cache_init(void)
{
- struct msdos_sb_info *sbi = MSDOS_SB(sb);
- int count;
+ fat_cache_cachep = kmem_cache_create("fat_cache",
+ sizeof(struct fat_cache),
+ 0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
+ init_once, NULL);
+ if (fat_cache_cachep == NULL)
+ return -ENOMEM;
+ return 0;
+}
- spin_lock_init(&sbi->cache_lock);
+void fat_cache_destroy(void)
+{
+ kmem_cache_destroy(fat_cache_cachep);
+}
- 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 inline struct fat_cache *fat_cache_alloc(struct inode *inode)
+{
+ return kmem_cache_alloc(fat_cache_cachep, GFP_KERNEL);
}
-static void
-fat_cache_lookup(struct inode *inode, int cluster, int *f_clu, int *d_clu)
+static inline void fat_cache_free(struct fat_cache *cache)
{
- 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;
+ BUG_ON(!list_empty(&cache->cache_list));
+ kmem_cache_free(fat_cache_cachep, cache);
+}
- spin_lock(&sbi->cache_lock);
+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);
+}
- 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;
+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;
+}
- 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;
+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;
}
}
-#ifdef DEBUG
- printk("cache miss\n");
-#endif
-out:
- spin_unlock(&sbi->cache_lock);
+ return NULL;
}
-#ifdef DEBUG
-static void list_cache(struct super_block *sb)
+static void fat_cache_add(struct inode *inode, struct fat_cache_id *new)
{
- 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("-- ");
+ 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;
}
- printk("\n");
+out_update_lru:
+ fat_cache_update_lru(inode, cache);
+out:
+ spin_unlock(&MSDOS_I(inode)->cache_lru_lock);
}
-#endif
/*
* Cache invalidation occurs rarely, thus the LRU chain is not updated. It
*/
static void __fat_cache_inval_inode(struct inode *inode)
{
- 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;
+ 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)
{
- struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
- spin_lock(&sbi->cache_lock);
+ spin_lock(&MSDOS_I(inode)->cache_lru_lock);
__fat_cache_inval_inode(inode);
- spin_unlock(&sbi->cache_lock);
+ spin_unlock(&MSDOS_I(inode)->cache_lru_lock);
}
-void fat_cache_add(struct inode *inode, int f_clu, int d_clu)
+static inline int cache_contiguous(struct fat_cache_id *cid, int dclus)
{
- 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;
+ cid->nr_contig++;
+ return ((cid->dcluster + cid->nr_contig) == dclus);
+}
- 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);
+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;
- fat_cache_lookup(inode, cluster, fclus, dclus);
+ 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)", __FUNCTION__,
MSDOS_I(inode)->i_pos);
- return -EIO;
+ nr = -EIO;
+ goto out;
}
- nr = fat_access(sb, *dclus, -1);
+ nr = fat_ent_read(inode, &fatent, *dclus);
if (nr < 0)
- return nr;
+ goto out;
else if (nr == FAT_ENT_FREE) {
fat_fs_panic(sb, "%s: invalid cluster chain"
" (i_pos %lld)", __FUNCTION__,
MSDOS_I(inode)->i_pos);
- return -EIO;
+ nr = -EIO;
+ goto out;
} else if (nr == FAT_ENT_EOF) {
- fat_cache_add(inode, *fclus, *dclus);
- return FAT_ENT_EOF;
+ fat_cache_add(inode, &cid);
+ goto out;
}
(*fclus)++;
*dclus = nr;
+ if (!cache_contiguous(&cid, *dclus))
+ cache_init(&cid, *fclus, *dclus);
}
- fat_cache_add(inode, *fclus, *dclus);
- return 0;
+ nr = 0;
+ fat_cache_add(inode, &cid);
+out:
+ fatent_brelse(&fatent);
+ return nr;
}
static int fat_bmap_cluster(struct inode *inode, int cluster)
return dclus;
}
-int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys)
+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);
int cluster, offset;
*phys = 0;
- if ((sbi->fat_bits != 32) &&
- (inode->i_ino == MSDOS_ROOT_INO || (S_ISDIR(inode->i_mode) &&
- !MSDOS_I(inode)->i_start))) {
- if (sector < (sbi->dir_entries >> sbi->dir_per_block_bits))
+ *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))
if (cluster < 0)
return cluster;
else if (cluster) {
- *phys = ((sector_t)cluster - 2) * sbi->sec_per_clus
- + sbi->data_start + offset;
+ *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;
}
-
-/* Free all clusters after the skip'th cluster. */
-int fat_free(struct inode *inode, int skip)
-{
- struct super_block *sb = inode->i_sb;
- int nr, ret, fclus, dclus;
-
- if (MSDOS_I(inode)->i_start == 0)
- return 0;
-
- if (skip) {
- ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus);
- if (ret < 0)
- return ret;
- else if (ret == FAT_ENT_EOF)
- return 0;
-
- nr = fat_access(sb, dclus, -1);
- if (nr == FAT_ENT_EOF)
- return 0;
- else if (nr > 0) {
- /*
- * write a new EOF, and get the remaining cluster
- * chain for freeing.
- */
- nr = fat_access(sb, dclus, FAT_ENT_EOF);
- }
- if (nr < 0)
- return nr;
-
- fat_cache_inval_inode(inode);
- } else {
- fat_cache_inval_inode(inode);
-
- nr = MSDOS_I(inode)->i_start;
- MSDOS_I(inode)->i_start = 0;
- MSDOS_I(inode)->i_logstart = 0;
- mark_inode_dirty(inode);
- }
-
- lock_fat(sb);
- do {
- nr = fat_access(sb, nr, FAT_ENT_FREE);
- if (nr < 0)
- goto error;
- else if (nr == FAT_ENT_FREE) {
- fat_fs_panic(sb, "%s: deleting beyond EOF (i_pos %lld)",
- __FUNCTION__, MSDOS_I(inode)->i_pos);
- nr = -EIO;
- goto error;
- }
- if (MSDOS_SB(sb)->free_clusters != -1)
- MSDOS_SB(sb)->free_clusters++;
- inode->i_blocks -= MSDOS_SB(sb)->cluster_size >> 9;
- } while (nr != FAT_ENT_EOF);
- fat_clusters_flush(sb);
- nr = 0;
-error:
- unlock_fat(sb);
-
- return nr;
-}
git://git.onelab.eu / linux-2.6.git / blobdiff