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>
diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 6c09623..3e20a12 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -391,6 +391,8 @@
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 @@
}
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