X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;ds=sidebyside;f=fs%2Ffat%2Ffatent.c;h=302e95c4af7e0c517704d987932411066c129d86;hb=9e975dae2970d22557662761c8505ce9fd165684;hp=ab171ea8e869b2cc9da6369abad3a83c970d2a96;hpb=be9bf30c73184e0f1e4e0a50fb193d2a551bf75e;p=linux-2.6-omap-h63xx.git

diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c
index ab171ea8e86..5b5f49061b7 100644
--- a/fs/fat/fatent.c
+++ b/fs/fat/fatent.c
@@ -6,6 +6,8 @@
 #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 *);
@@ -17,6 +19,8 @@ struct fatent_operations {
 	int (*ent_next)(struct fat_entry *);
 };
 
+static DEFINE_SPINLOCK(fat12_entry_lock);
+
 static void fat12_ent_blocknr(struct super_block *sb, int entry,
 			      int *offset, sector_t *blocknr)
 {
@@ -116,10 +120,13 @@ static int fat12_ent_get(struct fat_entry *fatent)
 	u8 **ent12_p = fatent->u.ent12_p;
 	int next;
 
+	spin_lock(&fat12_entry_lock);
 	if (fatent->entry & 1)
 		next = (*ent12_p[0] >> 4) | (*ent12_p[1] << 4);
 	else
 		next = (*ent12_p[1] << 8) | *ent12_p[0];
+	spin_unlock(&fat12_entry_lock);
+
 	next &= 0x0fff;
 	if (next >= BAD_FAT12)
 		next = FAT_ENT_EOF;
@@ -151,6 +158,7 @@ static void fat12_ent_put(struct fat_entry *fatent, int new)
 	if (new == FAT_ENT_EOF)
 		new = EOF_FAT12;
 
+	spin_lock(&fat12_entry_lock);
 	if (fatent->entry & 1) {
 		*ent12_p[0] = (new << 4) | (*ent12_p[0] & 0x0f);
 		*ent12_p[1] = new >> 4;
@@ -158,6 +166,7 @@ static void fat12_ent_put(struct fat_entry *fatent, int new)
 		*ent12_p[0] = new & 0xff;
 		*ent12_p[1] = (*ent12_p[1] & 0xf0) | (new >> 8);
 	}
+	spin_unlock(&fat12_entry_lock);
 
 	mark_buffer_dirty(fatent->bhs[0]);
 	if (fatent->nr_bhs == 2)
@@ -443,7 +452,8 @@ int fat_alloc_clusters(struct inode *inode, int *cluster, int nr_cluster)
 	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;
 	}
@@ -497,6 +507,7 @@ int fat_alloc_clusters(struct inode *inode, int *cluster, int nr_cluster)
 
 	/* Couldn't allocate the free entries */
 	sbi->free_clusters = 0;
+	sbi->free_clus_valid = 1;
 	sb->s_dirt = 1;
 	err = -ENOSPC;
 
@@ -526,6 +537,7 @@ int fat_free_clusters(struct inode *inode, int cluster)
 	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);
@@ -537,11 +549,23 @@ int fat_free_clusters(struct inode *inode, int cluster)
 			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++;
@@ -576,28 +600,54 @@ error:
 		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;
@@ -608,6 +658,7 @@ int fat_count_free_clusters(struct super_block *sb)
 		} while (fat_ent_next(sbi, &fatent));
 	}
 	sbi->free_clusters = free;
+	sbi->free_clus_valid = 1;
 	sb->s_dirt = 1;
 	fatent_brelse(&fatent);
 out: