From: Xiubo Li <xiubli@xxxxxxxxxx>
With max_mds > 1 and for a request which are choosing a random
mds rank and if the relating session is not opened yet, the request
will wait the session been opened and resend again. While every
time the request is beening __do_request, it will release the
req->session first and choose a random one again, so this time it
may choose another random mds rank. The worst case is that it will
open all the mds sessions one by one just before it can be
successfully sent out out.
Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
---
fs/ceph/mds_client.c | 20 ++++++++++++++++----
1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 68f3b5ed6ac8..d747e9baf9c9 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -876,7 +876,8 @@ static struct inode *get_nonsnap_parent(struct dentry *dentry)
* Called under mdsc->mutex.
*/
static int __choose_mds(struct ceph_mds_client *mdsc,
- struct ceph_mds_request *req)
+ struct ceph_mds_request *req,
+ bool *random)
{
struct inode *inode;
struct ceph_inode_info *ci;
@@ -886,6 +887,9 @@ static int __choose_mds(struct ceph_mds_client *mdsc,
u32 hash = req->r_direct_hash;
bool is_hash = test_bit(CEPH_MDS_R_DIRECT_IS_HASH, &req->r_req_flags);
+ if (random)
+ *random = false;
+
/*
* is there a specific mds we should try? ignore hint if we have
* no session and the mds is not up (active or recovering).
@@ -1021,6 +1025,9 @@ static int __choose_mds(struct ceph_mds_client *mdsc,
return mds;
random:
+ if (random)
+ *random = true;
+
mds = ceph_mdsmap_get_random_mds(mdsc->mdsmap);
dout("choose_mds chose random mds%d\n", mds);
return mds;
@@ -2556,6 +2563,7 @@ static void __do_request(struct ceph_mds_client *mdsc,
struct ceph_mds_session *session = NULL;
int mds = -1;
int err = 0;
+ bool random;
if (req->r_err || test_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags)) {
if (test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags))
@@ -2596,7 +2604,7 @@ static void __do_request(struct ceph_mds_client *mdsc,
put_request_session(req);
- mds = __choose_mds(mdsc, req);
+ mds = __choose_mds(mdsc, req, &random);
if (mds < 0 ||
ceph_mdsmap_get_state(mdsc->mdsmap, mds) < CEPH_MDS_STATE_ACTIVE) {
dout("do_request no mds or not active, waiting for map\n");
@@ -2624,8 +2632,12 @@ static void __do_request(struct ceph_mds_client *mdsc,
goto out_session;
}
if (session->s_state == CEPH_MDS_SESSION_NEW ||
- session->s_state == CEPH_MDS_SESSION_CLOSING)
+ session->s_state == CEPH_MDS_SESSION_CLOSING) {
__open_session(mdsc, session);
+ /* retry the same mds later */
+ if (random)
+ req->r_resend_mds = mds;
+ }
list_add(&req->r_wait, &session->s_waiting);
goto out_session;
}
@@ -2890,7 +2902,7 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
mutex_unlock(&mdsc->mutex);
goto out;
} else {
- int mds = __choose_mds(mdsc, req);
+ int mds = __choose_mds(mdsc, req, NULL);
if (mds >= 0 && mds != req->r_session->s_mds) {
dout("but auth changed, so resending\n");
__do_request(mdsc, req);
