libceph: add data pointers in osd op structures

An extent type osd operation currently implies that there will
be corresponding data supplied in the data portion of the request
(for write) or response (for read) message.  Similarly, an osd class
method operation implies a data item will be supplied to receive
the response data from the operation.

Add a ceph_osd_data pointer to each of those structures, and assign
it to point to eithre the incoming or the outgoing data structure in
the osd message.  The data is not always available when an op is
initially set up, so add two new functions to allow setting them
after the op has been initialized.

Begin to make use of the data item pointer available in the osd
operation rather than the request data in or out structure in
places where it's convenient.  Add some assertions to verify
pointers are always set the way they're expected to be.

This is a sort of stepping stone toward really moving the data
into the osd request ops, to allow for some validation before
making that jump.

This is the first in a series of patches that resolve:
    http://tracker.ceph.com/issues/4657

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_client.h
index a9c4089894c8..ae5193550fbf 100644
--- a/include/linux/ceph/osd_client.h
+++ b/include/linux/ceph/osd_client.h
@@ -87,12 +87,14 @@ struct ceph_osd_req_op {
                         u64 offset, length;
                         u64 truncate_size;
                         u32 truncate_seq;
+                        struct ceph_osd_data *osd_data;
                 } extent;
                 struct {
                         const char *class_name;
                         const char *method_name;
                         const void *request_data;
                         u32 request_data_len;
+                        struct ceph_osd_data *response_data;
                         __u8 class_len;
                         __u8 method_len;
                         __u8 argc;
@@ -236,10 +238,14 @@ extern void osd_req_op_extent_init(struct ceph_osd_req_op *op, u16 opcode,
                                         u64 offset, u64 length,
                                         u64 truncate_size, u32 truncate_seq);
 extern void osd_req_op_extent_update(struct ceph_osd_req_op *op, u64 length);
+extern void osd_req_op_extent_osd_data(struct ceph_osd_req_op *op,
+                                        struct ceph_osd_data *osd_data);
 extern void osd_req_op_cls_init(struct ceph_osd_req_op *op, u16 opcode,
                                         const char *class, const char *method,
                                         const void *request_data,
                                         size_t request_data_size);
+extern void osd_req_op_cls_response_data(struct ceph_osd_req_op *op,
+                                        struct ceph_osd_data *response_data);
 extern void osd_req_op_watch_init(struct ceph_osd_req_op *op, u16 opcode,
                                         u64 cookie, u64 version, int flag);