[PATCH v3 0/5] ceph/libceph: add support for sparse reads to msgr2 crc codepath

[Jeff Layton <jlayton@kernel.org>]

This is a revised version of the sparse read code I posted a week or so
ago. This work is required for fscrypt integration work, but may be
useful on its own as well, and may be applicable to RBD as well.

There are some significant differences from the last set:

- most of the extent data that comes in little-endian is now
  endian-converted in-place on BE arches.

- the OSD client now passes the extent map from the read back to the
  caller. This allows us to properly decrypt things at a higher level.
  It also makes it simpler for the caller to determine the actual length
  of the data read into the buffer

- this code should allow us to support multiple sparse read operations
  in an OSD request. That's not been tested yet though.

This has been tested with xfstests and it seems to work as expected, and
seems to be on-par performance-wise with "normal" reads.

Note that the messenger v2 CRC path is still the only part that has been
implemented so far. We'll need to implement support for v2-secure and v1
as well before we'll want to merge any of this.

We may also want to only selectively use sparse reads when necessary
but they don't seem to be any slower so it may be simpler to just always
use them.

Jeff Layton (5):
  libceph: add spinlock around osd->o_requests
  libceph: define struct ceph_sparse_extent and add some helpers
  libceph: add sparse read support to msgr2 crc state machine
  libceph: add sparse read support to OSD client
  ceph: convert to sparse reads

 fs/ceph/addr.c                  |  13 +-
 fs/ceph/file.c                  |  41 ++++-
 fs/ceph/super.h                 |   7 +
 include/linux/ceph/messenger.h  |  29 ++++
 include/linux/ceph/osd_client.h |  71 ++++++++-
 net/ceph/messenger.c            |   1 +
 net/ceph/messenger_v2.c         | 164 ++++++++++++++++++--
 net/ceph/osd_client.c           | 256 +++++++++++++++++++++++++++++++-
 8 files changed, 558 insertions(+), 24 deletions(-)

-- 
2.35.1