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@xxxxxxxx> --- 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
