From: resver <resver@60bc1c72-a15a-11de-b98f-4500b42dc123>
Date: Sat, 12 Nov 2011 21:27:00 +0000 (+0000)
Subject: Erase whole clusters instead of sectors. This fixes write performance regression... 
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=4ba683be8ebb02c5eb4d3a574cc14dab4f177216;p=android-x86%2Fexternal-exfat.git

Erase whole clusters instead of sectors. This fixes write performance regression caused by r207.

git-svn-id: http://exfat.googlecode.com/svn/trunk@231 60bc1c72-a15a-11de-b98f-4500b42dc123
---

diff --git a/libexfat/cluster.c b/libexfat/cluster.c
index 8bea507..7251c31 100644
--- a/libexfat/cluster.c
+++ b/libexfat/cluster.c
@@ -325,37 +325,38 @@ static int shrink_file(struct exfat* ef, struct exfat_node* node,
 
 static void erase_raw(struct exfat* ef, size_t size, off_t offset)
 {
-	exfat_write_raw(ef->zero_sector, size, offset, ef->fd);
+	exfat_write_raw(ef->zero_cluster, size, offset, ef->fd);
 }
 
 static int erase_range(struct exfat* ef, struct exfat_node* node,
 		uint64_t begin, uint64_t end)
 {
-	uint64_t sector_boundary;
+	uint64_t cluster_boundary;
 	cluster_t cluster;
 
 	if (begin >= end)
 		return 0;
 
-	sector_boundary = (node->size | (SECTOR_SIZE(*ef->sb) - 1)) + 1;
+	cluster_boundary = (begin | (CLUSTER_SIZE(*ef->sb) - 1)) + 1;
 	cluster = exfat_advance_cluster(ef, node,
-			node->size / CLUSTER_SIZE(*ef->sb));
+			begin / CLUSTER_SIZE(*ef->sb));
 	if (CLUSTER_INVALID(cluster))
 	{
 		exfat_error("invalid cluster in file");
 		return -EIO;
 	}
-	/* erase from the beginning to the closest sector boundary */
-	erase_raw(ef, MIN(sector_boundary, end) - node->size,
-			exfat_c2o(ef, cluster) + node->size % CLUSTER_SIZE(*ef->sb));
-	/* erase whole sectors */
-	while (sector_boundary < end)
+	/* erase from the beginning to the closest cluster boundary */
+	erase_raw(ef, MIN(cluster_boundary, end) - begin,
+			exfat_c2o(ef, cluster) + begin % CLUSTER_SIZE(*ef->sb));
+	/* erase whole clusters */
+	while (cluster_boundary < end)
 	{
-		if (sector_boundary % CLUSTER_SIZE(*ef->sb) == 0)
-			cluster = exfat_next_cluster(ef, node, cluster);
-		erase_raw(ef, SECTOR_SIZE(*ef->sb),
-			exfat_c2o(ef, cluster) + sector_boundary % CLUSTER_SIZE(*ef->sb));
-		sector_boundary += SECTOR_SIZE(*ef->sb);
+		cluster = exfat_next_cluster(ef, node, cluster);
+		/* the cluster cannot be invalid because we have just allocated it */
+		if (CLUSTER_INVALID(cluster))
+			exfat_bug("invalid cluster in file");
+		erase_raw(ef, CLUSTER_SIZE(*ef->sb), exfat_c2o(ef, cluster));
+		cluster_boundary += CLUSTER_SIZE(*ef->sb);
 	}
 	return 0;
 }
diff --git a/libexfat/exfat.h b/libexfat/exfat.h
index 84673dc..b7ee139 100644
--- a/libexfat/exfat.h
+++ b/libexfat/exfat.h
@@ -87,7 +87,7 @@ struct exfat
 	cmap;
 	char label[EXFAT_ENAME_MAX * 6 + 1]; /* a character can occupy up to
 											6 bytes in UTF-8 */
-	void* zero_sector;
+	void* zero_cluster;
 	int dmask, fmask;
 	uid_t uid;
 	gid_t gid;
diff --git a/libexfat/mount.c b/libexfat/mount.c
index 4240f63..17e6c16 100644
--- a/libexfat/mount.c
+++ b/libexfat/mount.c
@@ -173,28 +173,29 @@ int exfat_mount(struct exfat* ef, const char* spec, const char* options)
 		return -EIO;
 	}
 
-	ef->zero_sector = malloc(SECTOR_SIZE(*ef->sb));
-	if (ef->zero_sector == NULL)
+	ef->zero_cluster = malloc(CLUSTER_SIZE(*ef->sb));
+	if (ef->zero_cluster == NULL)
 	{
 		close(ef->fd);
 		free(ef->sb);
 		exfat_error("failed to allocate zero sector");
 		return -ENOMEM;
 	}
-	/* use zero_sector as a temporary buffer for VBR checksum verification */
-	if (verify_vbr_checksum(ef->zero_sector, SECTOR_SIZE(*ef->sb), ef->fd) != 0)
+	/* use zero_cluster as a temporary buffer for VBR checksum verification */
+	if (verify_vbr_checksum(ef->zero_cluster, SECTOR_SIZE(*ef->sb),
+			ef->fd) != 0)
 	{
-		free(ef->zero_sector);
+		free(ef->zero_cluster);
 		close(ef->fd);
 		free(ef->sb);
 		return -EIO;
 	}
-	memset(ef->zero_sector, 0, SECTOR_SIZE(*ef->sb));
+	memset(ef->zero_cluster, 0, CLUSTER_SIZE(*ef->sb));
 
 	ef->root = malloc(sizeof(struct exfat_node));
 	if (ef->root == NULL)
 	{
-		free(ef->zero_sector);
+		free(ef->zero_cluster);
 		close(ef->fd);
 		free(ef->sb);
 		exfat_error("failed to allocate root node");
@@ -232,7 +233,7 @@ error:
 	exfat_put_node(ef, ef->root);
 	exfat_reset_cache(ef);
 	free(ef->root);
-	free(ef->zero_sector);
+	free(ef->zero_cluster);
 	close(ef->fd);
 	free(ef->sb);
 	return -EIO;
@@ -244,8 +245,8 @@ void exfat_unmount(struct exfat* ef)
 	exfat_reset_cache(ef);
 	free(ef->root);
 	ef->root = NULL;
-	free(ef->zero_sector);
-	ef->zero_sector = NULL;
+	free(ef->zero_cluster);
+	ef->zero_cluster = NULL;
 	free(ef->cmap.chunk);
 	ef->cmap.chunk = NULL;
 	if (fsync(ef->fd) < 0)