From: David Woodhouse <David.Woodhouse@intel.com>
Date: Tue, 5 Aug 2008 17:05:46 +0000 (+0100)
Subject: Let the block device know when sectors can be discarded
X-Git-Tag: v2.6.28-rc1~733^2~124
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=8c540a96c175bdf55bda8707db04cec78b816454;p=linux-2.6-omap-h63xx.git

Let the block device know when sectors can be discarded

[hirofumi@mail.parknet.co.jp: discard _after_ checking for corrupt chains]

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---

diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c
index 302e95c4af7..fb98b3d847e 100644
--- a/fs/fat/fatent.c
+++ b/fs/fat/fatent.c
@@ -6,6 +6,7 @@
 #include <linux/module.h>
 #include <linux/fs.h>
 #include <linux/msdos_fs.h>
+#include <linux/blkdev.h>
 
 struct fatent_operations {
 	void (*ent_blocknr)(struct super_block *, int, int *, sector_t *);
@@ -535,6 +536,7 @@ 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);
@@ -551,6 +553,18 @@ int fat_free_clusters(struct inode *inode, int cluster)
 			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++;