ceph: explicitly specify page alignment in network messages

The alignment used for reading data into or out of pages used to be taken
from the data_off field in the message header.  This only worked as long
as the page alignment matched the object offset, breaking direct io to
non-page aligned offsets.

Instead, explicitly specify the page alignment next to the page vector
in the ceph_msg struct, and use that instead of the message header (which
probably shouldn't be trusted).  The alloc_msg callback is responsible for
filling in this field properly when it sets up the page vector.

Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 6c096239660c..3e20a122ffa2 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -391,6 +391,8 @@ void ceph_osdc_build_request(struct ceph_osd_request *req,
                 req->r_request->hdr.data_len = cpu_to_le32(data_len);
         }
 
+        req->r_request->page_alignment = req->r_page_alignment;
+
         BUG_ON(p > msg->front.iov_base + msg->front.iov_len);
         msg_size = p - msg->front.iov_base;
         msg->front.iov_len = msg_size;
@@ -1657,6 +1659,7 @@ static struct ceph_msg *get_reply(struct ceph_connection *con,
                 }
                 m->pages = req->r_pages;
                 m->nr_pages = req->r_num_pages;
+                m->page_alignment = req->r_page_alignment;
 #ifdef CONFIG_BLOCK
                 m->bio = req->r_bio;
 #endif