[PATCH v2 2/9] generic/015 fix to test the default non-mixed mode

[Anand Jain <anand.jain@oracle.com>]

commit 97575acd7495 (generic/015: Change the test filesystem size to
101mb), created 101mb FS instead of 100mb FS to make sure we create
a FS which is non mixed mode.

btrfs-progs commit 18e2663db3e1 (btrfs-progs: Add minimum device size
check) added a more accurate minimum required space to create the btrfs
FS in non mixed mode depending on the group profile, and considering
any group profiles we would need at least 256MB (with upward round off).

So this patch changes the FS size to be created by _scratch_sized_mkfs()
to 256MB so that we create the FS in non mixed mode for any group
profile.

Mixed blockgroup can be tested using the MKFS_OPTIONS explicitly.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
 tests/generic/015 | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/tests/generic/015 b/tests/generic/015
index 0f4d29800f4f..e6c8d7c37c07 100755
--- a/tests/generic/015
+++ b/tests/generic/015
@@ -37,11 +37,9 @@ _supported_os Linux
 _require_scratch
 _require_no_large_scratch_dev
 
-# With filesystems less than 100mb btrfs is created in mixed mode
-# which can lead to slight accounting errors of 1mb. Having the
-# fs be at least 101 mb ensures those errors are within the error
-# tolerance of 1%
-_scratch_mkfs_sized `expr 101 \* 1024 \* 1024` >/dev/null 2>&1 \
+# btrfs needs at least 256MB (with upward round off) to create a non-mixed mode
+# fs. Ref: btrfs-progs: btrfs_min_dev_size()
+_scratch_mkfs_sized $((256 * 1024 * 1024)) >> $seqres.full 2>&1 \
     || _fail "mkfs failed"
 _scratch_mount
 out=$SCRATCH_MNT/fillup.$$
-- 
1.8.3.1