ceph_writepages_start() invokes ceph_osdc_start_request(), which
increases the refcount of the ceph_osd_request object "req" and then
submit the request.
When ceph_writepages_start() returns or a new object is assigned to
"req", the original local reference of "req" becomes invalid, so the
refcount should be decreased to keep refcount balanced.
The reference counting issue happens in a normal path of
ceph_writepages_start(). Before NULL assigned to "req", the function
forgets to decrease its refcnt increased by ceph_osdc_start_request()
and will cause a refcnt leak.
Fix this issue by calling ceph_osdc_put_request() before the original
object pointed by "req" becomes invalid.
Fixes: 1d3576fd10f0 ("ceph: address space operations")
Signed-off-by: Xiyu Yang <xiyuyang19@xxxxxxxxxxxx>
Signed-off-by: Xin Tan <tanxin.ctf@xxxxxxxxx>
---
fs/ceph/addr.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 7ab616601141..b02c050a3418 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1126,6 +1126,7 @@ static int ceph_writepages_start(struct address_space *mapping,
req->r_mtime = inode->i_mtime;
rc = ceph_osdc_start_request(&fsc->client->osdc, req, true);
BUG_ON(rc);
+ ceph_osdc_put_request(req);
req = NULL;
wbc->nr_to_write -= i;
--
2.7.4
