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

Message

Mark Harmstone Oct. 22, 2024, 2:50 p.m. UTC

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, 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

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(-)