On 7.09.21 г. 10:42, Qu Wenruo wrote:

In btrfs there are at least 4 types of different bios currently:

- btrfs_io_bio
  It's used to specify IO for logical bytenr

Perhaps this structure needs to be turned into a btrfs_bio.

- btrfs_bio
  It's real physical bio

It's not even that, because btrfs_bio itself is not submitted at all,
it's really some sort of a semaphore, which is used to signal all stripe
bios i.e those bios which are submitted to the actual devices have
completed. In that regard it's not even a bio per-se, more like an
io_context.

- compressed_bio
  Only used for compressed read write.

This should be compressed_io_ctx or some such.

- btrfs_raid_bio
  Only used by RAID56

The naming of btrfs_bio and btrfs_io_bio is just anti-human.

Rename btrfs_io_bio to btrfs_logical_bio, and all involved helpers to
make clear at which layer the bio works.

Since we're here, also add extra comments on critical members like
@mirror_num.

Signed-off-by: Qu Wenruo <redacted>

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