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btrfs: read stripe len directly in btrfs_rmap_block 

extent_map::orig_block_len contains the size of a physical stripe when
it's used to describe block groups (calculated in read_one_chunk via
calc_stripe_length or calculated in decide_stripe_size and then assigned
to extent_map::orig_block_len in create_chunk). Exploit this fact to get
the size directly rather than opencoding the calculations. No functional
changes.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Nikolay Borisov 2020-04-03 16:40:34 +03:00 committed by David Sterba
parent 6a3c7f5c87
commit 9e22b92598
1 changed files with 3 additions and 10 deletions
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13
fs/btrfs/block-group.c
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@ -1657,19 +1657,12 @@ 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);
}
buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
if (!buf) {