[ 214/221] ceph: Fix infinite loop in __wake_requests

Greg Kroah-Hartman
2013-01-15T22:37:15Z

From: "Yan, Zheng" <zheng.z.yan@intel.com>

(cherry picked from commit ed75ec2cd19b47efcd292b6e23f58e56f4c5bc34)

__wake_requests() will enter infinite loop if we use it to wake
requests in the session->s_waiting list. __wake_requests() deletes
requests from the list and __do_request() adds requests back to
the list.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Sage Weil <sage@inktank.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/ceph/mds_client.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -1876,9 +1876,14 @@ finish:
static void __wake_requests(struct ceph_mds_client *mdsc,
struct list_head *head)
{
- struct ceph_mds_request *req, *nreq;
+ struct ceph_mds_request *req;
+ LIST_HEAD(tmp_list);

- list_for_each_entry_safe(req, nreq, head, r_wait) {
+ list_splice_init(head, &tmp_list);
+
+ while (!list_empty(&tmp_list)) {
+ req = list_entry(tmp_list.next,
+ struct ceph_mds_request, r_wait);
list_del_init(&req->r_wait);
__do_request(mdsc, req);
}