[PATCH 1/3] btrfs-progs: Initialize sub_stripes to 1 in btrfs_alloc_data_chunk

[Nikolay Borisov <nborisov@suse.com>]

sub_stripe variables is by default initialized to 0 and it's overriden
only in case we have RAID10 mode. This leads to the following (minor)
artifacts on a freshly created filesystem:

item 3 key (FIRST_CHUNK_TREE CHUNK_ITEM 30408704) itemoff 15863 itemsize 112
		length 1073741824 owner 2 stripe_len 65536 type METADATA|RAID1
		io_align 65536 io_width 65536 sector_size 4096
		num_stripes 2 sub_stripes 0
			stripe 0 devid 2 offset 9437184
			dev_uuid a020fc2f-b526-4800-9278-156f2f431fe9
			stripe 1 devid 1 offset 30408704
			dev_uuid 0f78aa72-4626-4057-a8f2-285f46b2c664

After balance resulting chunk item is:

item 3 key (FIRST_CHUNK_TREE CHUNK_ITEM 3251634176) itemoff 15863 itemsize 112
		length 268435456 owner 2 stripe_len 65536 type METADATA|RAID1
		io_align 65536 io_width 65536 sector_size 4096
		num_stripes 2 sub_stripes 1
			stripe 0 devid 2 offset 3230662656
			dev_uuid a020fc2f-b526-4800-9278-156f2f431fe9
			stripe 1 devid 1 offset 3251634176
			dev_uuid 0f78aa72-4626-4057-a8f2-285f46b2c664

Kernel code usually initializes it to 1, since it takes the value from
the raid description table which has it set to 1 for all but RAID10 types.
In userspace it has be statically initialized by 1 since we don't have
btrfs_bg_flags_to_raid_index. Eventually the kernel/userspace needs
to be merged but for now it wouldn't bring much value if this function
is copied.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
---
 volumes.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/volumes.c b/volumes.c
index fbbc22b5b1b3..1d088d93e788 100644
--- a/volumes.c
+++ b/volumes.c
@@ -993,7 +993,7 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 	int num_stripes = 1;
 	int max_stripes = 0;
 	int min_stripes = 1;
-	int sub_stripes = 0;
+	int sub_stripes = 1;
 	int looped = 0;
 	int ret;
 	int index;
@@ -1258,7 +1258,7 @@ int btrfs_alloc_data_chunk(struct btrfs_trans_handle *trans,
 	struct map_lookup *map;
 	u64 calc_size = SZ_8M;
 	int num_stripes = 1;
-	int sub_stripes = 0;
+	int sub_stripes = 1;
 	int ret;
 	int index;
 	int stripe_len = BTRFS_STRIPE_LEN;
-- 
2.7.4