Btrfs: stop silently switching single chunks to raid0 on balance

This has been causing a lot of confusion for quite a while now and a lot
of users were surprised by this (some of them were even stuck in a
ENOSPC situation which they couldn't easily get out of).  The addition
of restriper gives users a clear choice between raid0 and drive concat
setup so there's absolutely no excuse for us to keep doing this.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

1 files changed, 2 insertions, 3 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 1b831ac4c079..4269777f185e 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -6941,7 +6941,6 @@ static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
                              BTRFS_BLOCK_GROUP_RAID10))
                         return stripped | BTRFS_BLOCK_GROUP_DUP;
-                return flags;
         } else {
                 /* they already had raid on here, just return */
                 if (flags & stripped)
@@ -6954,9 +6953,9 @@ static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
                 if (flags & BTRFS_BLOCK_GROUP_DUP)
                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
 
-                /* turn single device chunks into raid0 */
-                return stripped | BTRFS_BLOCK_GROUP_RAID0;
+                /* this is drive concat, leave it alone */
         }
+
         return flags;
 }