Re: [PATCH v3 0/5] btrfs: encoded reads via io_uring

[Boris Burkov <boris@bur.io>]

On Mon, Oct 14, 2024 at 06:18:22PM +0100, Mark Harmstone wrote:
> This is a re-do of my previous patchsets: I wasn't happy with how
> synchronous the previous version was in many ways, nor quite how badly
> it butchered the existing ioctl.
> 
> This adds an io_uring cmd to btrfs to match the behaviour of the
> existing BTRFS_IOC_ENCODED_READ ioctl, which allows the reading of
> potentially compressed extents directly from the disk.
> 
> Pavel mentioned on the previous patches whether we definitely need to
> keep the inode and the extent locked while doing I/O; I think the answer
> is probably yes, a) to prevent races with no-COW extents, and b) to
> prevent the extent from being deallocated from under us. But I think
> it's possible to resolve this, as a future optimization.

What branch is this based off of? I attempted to apply it to the current
btrfs for-next and
"btrfs: change btrfs_encoded_read_regular_fill_pages to take a callback"
did not apply cleanly.

> 
> Mark Harmstone (5):
>   btrfs: remove pointless addition in btrfs_encoded_read
>   btrfs: change btrfs_encoded_read_regular_fill_pages to take a callback
>   btrfs: change btrfs_encoded_read so that reading of extent is done by
>     caller
>   btrfs: add nowait parameter to btrfs_encoded_read
>   btrfs: add io_uring command for encoded reads
> 
>  fs/btrfs/btrfs_inode.h |  23 ++-
>  fs/btrfs/file.c        |   1 +
>  fs/btrfs/inode.c       | 186 ++++++++++++++++--------
>  fs/btrfs/ioctl.c       | 316 ++++++++++++++++++++++++++++++++++++++++-
>  fs/btrfs/ioctl.h       |   1 +
>  fs/btrfs/send.c        |  15 +-
>  6 files changed, 476 insertions(+), 66 deletions(-)
> 
> -- 
> 2.44.2
>