Re: [PATCH v4 0/5] btrfs: io_uring interface for encoded reads

[Anand Jain <anand.jain@oracle.com>]

On 22/10/24 22:50, Mark Harmstone wrote:
> This is version 4 of a patch series to add an io_uring interface for
> encoded reads. The principal use case for this is to eventually allow

> btrfs send and receive to operate asynchronously,

How would you define an asynchronously operated Btrfs send and receive?
Are you referring to Btrfs send and receive the leveraging io_uring
asynchronous operation?

> the lack of io_uring
> encoded I/O being one of the main blockers for this.

> 
> I've written a test program for this, which demonstrates the ioctl and
> io_uring interface produce identical results: https://github.com/maharmstone/io_uring-encoded

Thanks, Anand


> 
> Changelog:
> v4:
> * Rewritten to avoid taking function pointer
> * Removed nowait parameter, as this could be derived from iocb flags
> * Fixed structure not getting properly initialized
> * Followed ioctl by capping uncompressed reads at EOF
> * Rebased against btrfs/for-next
> * Formatting fixes
> * Rearranged structs to minimize holes
> * Published test program
> * Fixed potential data race with userspace
> * Changed to use io_uring_cmd_to_pdu helper function
> * Added comments for potentially confusing parts of the code
> 
> v3:
> * Redo of previous versions
> 
> Mark Harmstone (5):
>    btrfs: remove pointless addition in btrfs_encoded_read
>    btrfs: change btrfs_encoded_read so that reading of extent is done by
>      caller
>    btrfs: don't sleep in btrfs_encoded_read if IOCB_NOWAIT set
>    btrfs: move priv off stack in btrfs_encoded_read_regular_fill_pages
>    btrfs: add io_uring command for encoded reads
> 
>   fs/btrfs/btrfs_inode.h |  13 +-
>   fs/btrfs/file.c        |   1 +
>   fs/btrfs/inode.c       | 175 ++++++++++++++-------
>   fs/btrfs/ioctl.c       | 342 ++++++++++++++++++++++++++++++++++++++++-
>   fs/btrfs/ioctl.h       |   2 +
>   fs/btrfs/send.c        |   3 +-
>   6 files changed, 473 insertions(+), 63 deletions(-)
>