[PATCH] btrfs: volumes: Remove the meaningless condition of minimal nr_devs when allocating a chunk

[Qu Wenruo <wqu@suse.com>]

When checking the minimal nr_devs, there is one dead and meaningless
condition:

if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

This condition is meaningless, @devs_increment has nothing to do with
@sub_stripes.

In fact, in btrfs_raid_array[], profile with sub_stripes larger than 1
(RAID10) already has the @devs_increment set to 2.
So no need to multiple it by @sub_stripes.

And above condition is also dead.
For RAID10, @devs_increment * @sub_stripes equals 4, which is also the
@devs_min of RAID10.
For other profiles, @sub_stripes is always 1, and since @ndevs is
rounded down to @devs_increment, the condition will always be true.

Remove the meaningless condition to make later reader wander less.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/volumes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 215e85e22c8e..cb0a8d27661b 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4729,7 +4729,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 	/* round down to number of usable stripes */
 	ndevs = round_down(ndevs, devs_increment);
 
-	if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
+	if (ndevs < devs_min) {
 		ret = -ENOSPC;
 		goto error;
 	}
-- 
2.16.1