[PATCH 1/2] btrfs: enable discard support

[PATCH 1/2] btrfs: enable discard support

[Christoph Hellwig, Christoph Hellwig]

The discard support code in btrfs currently is guarded by ifdefs for
BIO_RW_DISCARD, which is never defines as it's the name of an enum
memeber.  Just remove the useless ifdefs to actually enable the code.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/fs/btrfs/extent-tree.c
===================================================================
--- linux-2.6.orig/fs/btrfs/extent-tree.c	2009-10-07 11:04:18.451256181 -0400
+++ linux-2.6/fs/btrfs/extent-tree.c	2009-10-07 11:04:26.225005458 -0400
@@ -1568,19 +1568,16 @@ static int remove_extent_backref(struct 
 	return ret;
 }
 
-#ifdef BIO_RW_DISCARD
 static void btrfs_issue_discard(struct block_device *bdev,
 				u64 start, u64 len)
 {
 	blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL,
 			     DISCARD_FL_BARRIER);
 }
-#endif
 
 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
 				u64 num_bytes)
 {
-#ifdef BIO_RW_DISCARD
 	int ret;
 	u64 map_length = num_bytes;
 	struct btrfs_multi_bio *multi = NULL;
@@ -1604,9 +1601,6 @@ static int btrfs_discard_extent(struct b
 	}
 
 	return ret;
-#else
-	return 0;
-#endif
 }
 
 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,

Re: [PATCH 1/2] btrfs: enable discard support

[Chris Mason]

On Wed, Oct 14, 2009 at 03:03:02AM +0200, Christoph Hellwig wrote:
> The discard support code in btrfs currently is guarded by ifdefs for
> BIO_RW_DISCARD, which is never defines as it's the name of an enum
> memeber.  Just remove the useless ifdefs to actually enable the code.

Thanks Christoph,

Any objection to me reordering these?  That way someone bisecting around
won't hit discard support without expecting it.

-chris

Re: [PATCH 1/2] btrfs: enable discard support

[Christoph Hellwig]

On Wed, Oct 14, 2009 at 09:27:04AM -0400, Chris Mason wrote:
> On Wed, Oct 14, 2009 at 03:03:02AM +0200, Christoph Hellwig wrote:
> > The discard support code in btrfs currently is guarded by ifdefs for
> > BIO_RW_DISCARD, which is never defines as it's the name of an enum
> > memeber.  Just remove the useless ifdefs to actually enable the code.
> 
> Thanks Christoph,
> 
> Any objection to me reordering these?  That way someone bisecting around
> won't hit discard support without expecting it.

I'm perfectly fine with reordering them.