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

Mark Harmstone
2024-10-14T17:18:51Z

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.

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