ceph: avoid updating mds_wanted too frequently

user space may open/close single file frequently. It's not good
to send a clientcaps message to mds for each open/close syscall.

Signed-off-by: Yan, Zheng <zyan@redhat.com>

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index e3a2a3f32568b801a94a9066c058b3e756eab391..d941c48e8bff096abfa2e26d181e51539faf0f97 100644 (file)
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1184,6 +1184,13 @@ static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
                delayed = 1;
        }
        ci->i_ceph_flags &= ~(CEPH_I_NODELAY | CEPH_I_FLUSH);
+       if (want & ~cap->mds_wanted) {
+               /* user space may open/close single file frequently.
+                * This avoids droping mds_wanted immediately after
+                * requesting new mds_wanted.
+                */
+               __cap_set_timeouts(mdsc, ci);
+       }
 
        cap->issued &= retain;  /* drop bits we don't want */
        if (cap->implemented & ~cap->issued) {
@@ -2485,15 +2492,14 @@ again:
                                goto out_unlock;
                        }
                        mds_wanted = __ceph_caps_mds_wanted(ci);
-                       if ((mds_wanted & need) != need) {
+                       if (need & ~(mds_wanted & need)) {
                                dout("get_cap_refs %p caps were dropped"
                                     " (session killed?)\n", inode);
                                *err = -ESTALE;
                                ret = 1;
                                goto out_unlock;
                        }
-                       if ((mds_wanted & file_wanted) ==
-                           (file_wanted & (CEPH_CAP_FILE_RD|CEPH_CAP_FILE_WR)))
+                       if (!(file_wanted & ~mds_wanted))
                                ci->i_ceph_flags &= ~CEPH_I_CAP_DROPPED;
                }