On 2019/10/30 下午8:22, Nikolay Borisov wrote: > 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> Reviewed-by: Qu Wenruo <wqu@xxxxxxxx> I guess the tree-checker skips this check except for RAID10 just to work around this problem. Thanks, Qu > --- > 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; >
