libceph: reset sparse-read state in osd_fault()

When a fault occurs, the connection is abandoned, reestablished, and any
pending operations are retried. The OSD client tracks the progress of a
sparse-read reply using a separate state machine, largely independent of
the messenger's state.

If a connection is lost mid-payload or the sparse-read state machine
returns an error, the sparse-read state is not reset. The OSD client
will then interpret the beginning of a new reply as the continuation of
the old one. If this makes the sparse-read machinery enter a failure
state, it may never recover, producing loops like:

  libceph:  [0] got 0 extents
  libceph: data len 142248331 != extent len 0
  libceph: osd0 (1)...:6801 socket error on read
  libceph: data len 142248331 != extent len 0
  libceph: osd0 (1)...:6801 socket error on read

Therefore, reset the sparse-read state in osd_fault(), ensuring retries
start from a clean state.

Cc: stable@vger.kernel.org
Fixes: f628d7999727 ("libceph: add sparse read support to OSD client")
Signed-off-by: Sam Edwards <CFSworks@gmail.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 3667319b949ddcdab76ff7182a08a39b50d83b16..1a7be2f615dc3e2e9de168aad2e08feee19d451e 100644 (file)
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -4281,6 +4281,9 @@ static void osd_fault(struct ceph_connection *con)
                goto out_unlock;
        }
 
+       osd->o_sparse_op_idx = -1;
+       ceph_init_sparse_read(&osd->o_sparse_read);
+
        if (!reopen_osd(osd))
                kick_osd_requests(osd);
        maybe_request_map(osdc);