[PATCH 3/3] btrfs: defrag: remove the physical adjacent extents rejection in defrag_check_next_extent()

[Qu Wenruo <wqu@suse.com>]

There is a rejection for physically adjacent extents in
defrag_check_next_extent() from the very beginning.

The check will reject physically adjacent extents which are also large
enough.

The extent size threshold check is now a generic check, and the
benefit of rejecting physically adjacent extents is unsure.

Sure physically adjacent extents means no extra seek time, thus
defragging them may not bring much help.

On the other hand, btrfs also benefits from reduced number of extents
(which can reduce the size of extent tree, thus reduce the mount time).

So such rejection is not a full win.

Remove such check, and policy on which extents should be defragged is
mostly on @extent_thresh and @newer_than parameters.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/ioctl.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 2911df12fc48..0929d08bb378 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1069,9 +1069,6 @@ static bool defrag_check_next_extent(struct inode *inode, struct extent_map *em,
 	/* Extent is already large enough */
 	if (next->len >= extent_thresh)
 		goto out;
-	/* Physically adjacent */
-	if ((em->block_start + em->block_len == next->block_start))
-		goto out;
 	ret = true;
 out:
 	free_extent_map(next);
-- 
2.34.1