ceph: fix freeing inode vs removing session caps race

[karo-tx-linux.git] / fs / ceph / mds_client.c

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 6b40d8112c64080e800ec5e2722dcfca15b76ad5..cbf08203e00dce56e472ca0ac7ff76b3a71bf832 100644 (file)
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -1031,6 +1031,37 @@ static void remove_session_caps(struct ceph_mds_session *session)
 {
        dout("remove_session_caps on %p\n", session);
        iterate_session_caps(session, remove_session_caps_cb, NULL);
+
+       spin_lock(&session->s_cap_lock);
+       if (session->s_nr_caps > 0) {
+               struct super_block *sb = session->s_mdsc->fsc->sb;
+               struct inode *inode;
+               struct ceph_cap *cap, *prev = NULL;
+               struct ceph_vino vino;
+               /*
+                * iterate_session_caps() skips inodes that are being
+                * deleted, we need to wait until deletions are complete.
+                * __wait_on_freeing_inode() is designed for the job,
+                * but it is not exported, so use lookup inode function
+                * to access it.
+                */
+               while (!list_empty(&session->s_caps)) {
+                       cap = list_entry(session->s_caps.next,
+                                        struct ceph_cap, session_caps);
+                       if (cap == prev)
+                               break;
+                       prev = cap;
+                       vino = cap->ci->i_vino;
+                       spin_unlock(&session->s_cap_lock);
+
+                       inode = ceph_lookup_inode(sb, vino);
+                       iput(inode);
+
+                       spin_lock(&session->s_cap_lock);
+               }
+       }
+       spin_unlock(&session->s_cap_lock);
+
        BUG_ON(session->s_nr_caps > 0);
        BUG_ON(!list_empty(&session->s_cap_flushing));
        cleanup_cap_releases(session);