Re: [PATCH 2/5] [FAT] Let the block device know when sectors can be discarded

[David Woodhouse <dwmw2@infradead.org>]

On Wed, 2008-08-06 at 22:37 +0100, David Woodhouse wrote:
> > Yes and no. I guess bytes or _fs_-blocksize is good interface for fs.
> 
> OK. I'll do the latter; thank you.

Incremental patch over what I posted before...

diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c
index 5970fd6..a8b10ac 100644
--- a/fs/fat/fatent.c
+++ b/fs/fat/fatent.c
@@ -541,11 +541,6 @@ int fat_free_clusters(struct inode *inode, int cluster)
 	fatent_init(&fatent);
 	lock_fat(sbi);
 	do {
-		/* Issue discard for the sectors we no longer care about */
-		blkdev_issue_discard(sb->s_bdev,
-				     fat_clus_to_blknr(sbi, cluster),
-				     sbi->sec_per_clus, NULL);
-
 		cluster = fat_ent_read(inode, &fatent, cluster);
 		if (cluster < 0) {
 			err = cluster;
@@ -557,6 +552,10 @@ int fat_free_clusters(struct inode *inode, int cluster)
 			goto error;
 		}
 
+		/* Issue discard for the sectors we no longer care about */
+		sb_issue_discard(sb, fat_clus_to_blknr(sbi, fatent.entry),
+				 sbi->sec_per_clus, NULL);
+
 		ops->ent_put(&fatent, FAT_ENT_FREE);
 		if (sbi->free_clusters != -1) {
 			sbi->free_clusters++;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 3f077a5..9b33909 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -840,6 +840,15 @@ extern int blkdev_issue_flush(struct block_device *, sector_t *);
 extern int blkdev_issue_discard(struct block_device *, sector_t sector,
 				unsigned nr_sects, bio_end_io_t *);
 
+static inline int sb_issue_discard(struct super_block *sb,
+				   sector_t block, unsigned nr_blocks,
+				   bio_end_io_t *endio)
+{
+	block <<= (sb->s_blocksize_bits - 9);
+	nr_blocks <<= (sb->s_blocksize_bits - 9);
+	return blkdev_issue_discard(sb->s_bdev, block, nr_blocks, endio);
+}
+
 /*
 * command filter functions
 */
diff --git a/mm/bounce.c b/mm/bounce.c
index b6d2d0f..1cfe193 100644
--- a/mm/bounce.c
+++ b/mm/bounce.c
@@ -267,7 +267,7 @@ void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
 	/*
 	 * Data-less bio, nothing to bounce
 	 */
-	if (bio_empty_barrier(*bio_orig))
+	if (bio_dataless(*bio_orig))
 		return;
 
 	/*


-- 
David Woodhouse                            Open Source Technology Centre
David.Woodhouse@intel.com                              Intel Corporation