On 4/3/20 9:40 AM, Nikolay Borisov wrote:
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@xxxxxxxx>
---
Hello David,
You had some reservations for this patch but now I've expanded the changelog to
explain why it's safe to do so.
fs/btrfs/block-group.c | 13 +++----------
1 file changed, 3 insertions(+), 10 deletions(-)
diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 786849fcc319..d0dbaa470b88 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1628,19 +1628,12 @@ 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);
- }
So now data_stripe_length is different in the RAID1 case and the RAID1C* case,
right? Is that ok? I *think* it is, but I'm a little drunk and can't really
reason it out well. Thanks,
Josef
