From 907c5fd7a4bd7da62d6c7cb418e4df81ec77e2f5 Mon Sep 17 00:00:00 2001
From: Naohiro Aota <naohiro.aota@wdc.com>
Date: Tue, 6 Apr 2021 17:05:50 +0900
Subject: [PATCH] btrfs-progs: fix to use half the available space for DUP
 profile

In the DUP profile, we can use only half of the space available in a
device extent. Fix the calculation of calc_size for it.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
 kernel-shared/volumes.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel-shared/volumes.c b/kernel-shared/volumes.c
index c493479e..264c1daa 100644
--- a/kernel-shared/volumes.c
+++ b/kernel-shared/volumes.c
@@ -1323,7 +1323,10 @@ again:
 		}
 		if (!looped && max_avail > 0) {
 			looped = 1;
-			ctl.calc_size = max_avail;
+			if (ctl.type & BTRFS_BLOCK_GROUP_DUP)
+				ctl.calc_size = max_avail / 2;
+			else
+				ctl.calc_size = max_avail;
 			goto again;
 		}
 		return -ENOSPC;