On 14.01.20 г. 18:54 ч., David Sterba wrote:
> On Tue, Nov 19, 2019 at 02:05:54PM +0200, Nikolay Borisov wrote:
>> extent_map::orig_block_len contains the size of a physical stripe when
>> it's used to describe block groups. So get the size directly in
>> btrfs_rmap_block rather than open-coding the calculations. No
>> functional changes.
>>
>> Signed-off-by: Nikolay Borisov <nborisov@xxxxxxxx>
>> ---
>> fs/btrfs/block-group.c | 11 +++--------
>> 1 file changed, 3 insertions(+), 8 deletions(-)
>>
>> diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
>> index c3b1f304bc70..2ab4d9cb598a 100644
>> --- a/fs/btrfs/block-group.c
>> +++ b/fs/btrfs/block-group.c
>> @@ -1546,17 +1546,12 @@ int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
>> return -EIO;
>>
>> map = em->map_lookup;
>> - data_stripe_length = em->len;
>> + data_stripe_length = em->orig_block_len;
>> io_stripe_size = map->stripe_len;
>>
>> - if (map->type & BTRFS_BLOCK_GROUP_RAID10)
>> - data_stripe_length = div_u64(data_stripe_length, map->num_stripes / map->sub_stripes);
>> - else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
>> - data_stripe_length = div_u64(data_stripe_length, map->num_stripes);
>> - else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
>> - data_stripe_length = div_u64(data_stripe_length, nr_data_stripes(map));
>> + /* For raid5/6 adjust to a full IO stripe length */
>> + if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
>> io_stripe_size = map->stripe_len * nr_data_stripes(map);
>
> I'm not convinced this is 'no functional change' so will merge only
> patches 1-4 for now as I have reviewed them and want to add them to
> misc-next before the 5.6 freeze.
>
THe easiest way to convince yourself is to work out the maths happening
in __btrfs_alloc_chunk, since orig_block_len for chunks is set there.
