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/messenger.c b/net/ceph/messenger.c
index d379abf..1c7a2ec4 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -540,8 +540,7 @@
/* initialize page iterator */
con->out_msg_pos.page = 0;
if (m->pages)
- con->out_msg_pos.page_pos =
- le16_to_cpu(m->hdr.data_off) & ~PAGE_MASK;
+ con->out_msg_pos.page_pos = m->page_alignment;
else
con->out_msg_pos.page_pos = 0;
con->out_msg_pos.data_pos = 0;
@@ -1491,7 +1490,7 @@
struct ceph_msg *m = con->in_msg;
int ret;
int to, left;
- unsigned front_len, middle_len, data_len, data_off;
+ unsigned front_len, middle_len, data_len;
int datacrc = con->msgr->nocrc;
int skip;
u64 seq;
@@ -1527,7 +1526,6 @@
data_len = le32_to_cpu(con->in_hdr.data_len);
if (data_len > CEPH_MSG_MAX_DATA_LEN)
return -EIO;
- data_off = le16_to_cpu(con->in_hdr.data_off);
/* verify seq# */
seq = le64_to_cpu(con->in_hdr.seq);
@@ -1575,7 +1573,7 @@
con->in_msg_pos.page = 0;
if (m->pages)
- con->in_msg_pos.page_pos = data_off & ~PAGE_MASK;
+ con->in_msg_pos.page_pos = m->page_alignment;
else
con->in_msg_pos.page_pos = 0;
con->in_msg_pos.data_pos = 0;
@@ -2300,6 +2298,7 @@
/* data */
m->nr_pages = 0;
+ m->page_alignment = 0;
m->pages = NULL;
m->pagelist = NULL;
m->bio = NULL;
@@ -2369,6 +2368,7 @@
type, front_len);
return NULL;
}
+ msg->page_alignment = le16_to_cpu(hdr->data_off);
}
memcpy(&msg->hdr, &con->in_hdr, sizeof(con->in_hdr));