(This patch is available in branch "review/wip-4450" of the
ceph-client git repository. It corrects a problem that arose
in the commit before it. It is not the topmost commit because
the one before and two after were three patches that had been
previously reviewed. Rather than change the reviewed patch,
I'm keeping this fix separate and have just rebased the two
that follow it.)
In write_partial_message_data() we aggregate the crc for the data
portion of the message as each new piece of the data item is
encountered. Because it was computed *before* sending the data, if
an attempt to send a new piece resulted in 0 bytes being sent, the
crc crc across that piece would erroneously get computed again and
added to the aggregate result. This would occasionally happen in
the evnet of a connection failure.
The crc value isn't really needed until the complete value is known
after sending all data, so there's no need to compute it before
sending.
So don't calculate the crc for a piece until *after* we know at
least one byte of it has been sent. That will avoid this problem.
This resolves:
http://tracker.ceph.com/issues/4450
Signed-off-by: Alex Elder <elder@xxxxxxxxxxx>
---
net/ceph/messenger.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 02a37a5..3f5137c 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -1467,8 +1467,6 @@ static int write_partial_message_data(struct
ceph_connection *con)
page = ceph_msg_data_next(&msg->data, &page_offset, &length,
&last_piece);
- if (do_datacrc && cursor->need_crc)
- crc = ceph_crc32c_page(crc, page, page_offset, length);
ret = ceph_tcp_sendpage(con->sock, page, page_offset,
length, last_piece);
if (ret <= 0) {
@@ -1477,6 +1475,8 @@ static int write_partial_message_data(struct
ceph_connection *con)
return ret;
}
+ if (do_datacrc && cursor->need_crc)
+ crc = ceph_crc32c_page(crc, page, page_offset, length);
out_msg_pos_next(con, page, length, (size_t) ret);
}
--
1.7.9.5
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