On 12.10.2017 11:43, Anand Jain wrote:
> A cleanup patch, use need_full_stripe() to replace the open code.
The code is equivalent by merit of De Morgan's law (I had to actually go
look up the equivalence classes before I convinced myself it was correct)
~A ^ ~B == ~(A or B)
Reviewed-by: Nikolay Borisov <nborisov@xxxxxxxx>
>
> Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
> ---
> fs/btrfs/volumes.c | 16 ++++++----------
> 1 file changed, 6 insertions(+), 10 deletions(-)
>
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 3b3ba1ecd88b..f5dee43f8f3f 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -5673,10 +5673,10 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
> if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
> stripe_nr = div_u64_rem(stripe_nr, map->num_stripes,
> &stripe_index);
> - if (op != BTRFS_MAP_WRITE && op != BTRFS_MAP_GET_READ_MIRRORS)
> + if (!need_full_stripe(op))
> mirror_num = 1;
> } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
> - if (op == BTRFS_MAP_WRITE || op == BTRFS_MAP_GET_READ_MIRRORS)
> + if (need_full_stripe(op))
> num_stripes = map->num_stripes;
> else if (mirror_num)
> stripe_index = mirror_num - 1;
> @@ -5689,7 +5689,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
> }
>
> } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
> - if (op == BTRFS_MAP_WRITE || op == BTRFS_MAP_GET_READ_MIRRORS) {
> + if (need_full_stripe(op)) {
> num_stripes = map->num_stripes;
> } else if (mirror_num) {
> stripe_index = mirror_num - 1;
> @@ -5703,7 +5703,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
> stripe_nr = div_u64_rem(stripe_nr, factor, &stripe_index);
> stripe_index *= map->sub_stripes;
>
> - if (op == BTRFS_MAP_WRITE || op == BTRFS_MAP_GET_READ_MIRRORS)
> + if (need_full_stripe(op))
> num_stripes = map->sub_stripes;
> else if (mirror_num)
> stripe_index += mirror_num - 1;
> @@ -5718,9 +5718,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
> }
>
> } else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
> - if (need_raid_map &&
> - (op == BTRFS_MAP_WRITE || op == BTRFS_MAP_GET_READ_MIRRORS ||
> - mirror_num > 1)) {
> + if (need_raid_map && (need_full_stripe(op) || mirror_num > 1)) {
> /* push stripe_nr back to the start of the full stripe */
> stripe_nr = div64_u64(raid56_full_stripe_start,
> stripe_len * nr_data_stripes(map));
> @@ -5747,9 +5745,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
> /* We distribute the parity blocks across stripes */
> div_u64_rem(stripe_nr + stripe_index, map->num_stripes,
> &stripe_index);
> - if ((op != BTRFS_MAP_WRITE &&
> - op != BTRFS_MAP_GET_READ_MIRRORS) &&
> - mirror_num <= 1)
> + if (!need_full_stripe(op) && mirror_num <= 1)
> mirror_num = 1;
> }
> } else {
>
--
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