#include <linux/module.h>
#include <linux/fs.h>
#include <linux/msdos_fs.h>
+#include <linux/blkdev.h>
+#include "fat.h"
struct fatent_operations {
void (*ent_blocknr)(struct super_block *, int, int *, sector_t *);
/* Is this fatent's blocks including this entry? */
if (!fatent->nr_bhs || bhs[0]->b_blocknr != blocknr)
return 0;
- /* Does this entry need the next block? */
- if (sbi->fat_bits == 12 && (offset + 1) >= sb->s_blocksize) {
- if (fatent->nr_bhs != 2 || bhs[1]->b_blocknr != (blocknr + 1))
- return 0;
+ if (sbi->fat_bits == 12) {
+ if ((offset + 1) < sb->s_blocksize) {
+ /* This entry is on bhs[0]. */
+ if (fatent->nr_bhs == 2) {
+ brelse(bhs[1]);
+ fatent->nr_bhs = 1;
+ }
+ } else {
+ /* This entry needs the next block. */
+ if (fatent->nr_bhs != 2)
+ return 0;
+ if (bhs[1]->b_blocknr != (blocknr + 1))
+ return 0;
+ }
}
ops->ent_set_ptr(fatent, offset);
return 1;
BUG_ON(nr_cluster > (MAX_BUF_PER_PAGE / 2)); /* fixed limit */
lock_fat(sbi);
- if (sbi->free_clusters != -1 && sbi->free_clusters < nr_cluster) {
+ if (sbi->free_clusters != -1 && sbi->free_clus_valid &&
+ sbi->free_clusters < nr_cluster) {
unlock_fat(sbi);
return -ENOSPC;
}
/* Couldn't allocate the free entries */
sbi->free_clusters = 0;
+ sbi->free_clus_valid = 1;
sb->s_dirt = 1;
err = -ENOSPC;
struct fat_entry fatent;
struct buffer_head *bhs[MAX_BUF_PER_PAGE];
int i, err, nr_bhs;
+ int first_cl = cluster;
nr_bhs = 0;
fatent_init(&fatent);
goto error;
} else if (cluster == FAT_ENT_FREE) {
fat_fs_panic(sb, "%s: deleting FAT entry beyond EOF",
- __FUNCTION__);
+ __func__);
err = -EIO;
goto error;
}
+ /*
+ * Issue discard for the sectors we no longer care about,
+ * batching contiguous clusters into one request
+ */
+ if (cluster != fatent.entry + 1) {
+ int nr_clus = fatent.entry - first_cl + 1;
+
+ sb_issue_discard(sb, fat_clus_to_blknr(sbi, first_cl),
+ nr_clus * sbi->sec_per_clus);
+ first_cl = cluster;
+ }
+
ops->ent_put(&fatent, FAT_ENT_FREE);
if (sbi->free_clusters != -1) {
sbi->free_clusters++;
brelse(bhs[i]);
unlock_fat(sbi);
- fat_clusters_flush(sb);
-
return err;
}
EXPORT_SYMBOL_GPL(fat_free_clusters);
+/* 128kb is the whole sectors for FAT12 and FAT16 */
+#define FAT_READA_SIZE (128 * 1024)
+
+static void fat_ent_reada(struct super_block *sb, struct fat_entry *fatent,
+ unsigned long reada_blocks)
+{
+ struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;
+ sector_t blocknr;
+ int i, offset;
+
+ ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr);
+
+ for (i = 0; i < reada_blocks; i++)
+ sb_breadahead(sb, blocknr + i);
+}
+
int fat_count_free_clusters(struct super_block *sb)
{
struct msdos_sb_info *sbi = MSDOS_SB(sb);
struct fatent_operations *ops = sbi->fatent_ops;
struct fat_entry fatent;
+ unsigned long reada_blocks, reada_mask, cur_block;
int err = 0, free;
lock_fat(sbi);
- if (sbi->free_clusters != -1)
+ if (sbi->free_clusters != -1 && sbi->free_clus_valid)
goto out;
+ reada_blocks = FAT_READA_SIZE >> sb->s_blocksize_bits;
+ reada_mask = reada_blocks - 1;
+ cur_block = 0;
+
free = 0;
fatent_init(&fatent);
fatent_set_entry(&fatent, FAT_START_ENT);
while (fatent.entry < sbi->max_cluster) {
+ /* readahead of fat blocks */
+ if ((cur_block & reada_mask) == 0) {
+ unsigned long rest = sbi->fat_length - cur_block;
+ fat_ent_reada(sb, &fatent, min(reada_blocks, rest));
+ }
+ cur_block++;
+
err = fat_ent_read_block(sb, &fatent);
if (err)
goto out;
} while (fat_ent_next(sbi, &fatent));
}
sbi->free_clusters = free;
+ sbi->free_clus_valid = 1;
sb->s_dirt = 1;
fatent_brelse(&fatent);
out: