gfs2: Fix remote demote of weak glock holders

When we mock up a temporary holder in gfs2_glock_cb to demote weak holders in
response to a remote locking conflict, we don't set the HIF_HOLDER flag.  This
causes function may_grant to BUG.  Fix by setting the missing HIF_HOLDER flag
in the mock glock holder.

In addition, define the mock glock holder where it is used.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 8dbd6fe..44a7a42 100644 (file)
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -1857,7 +1857,6 @@ void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
 
 void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
 {
-       struct gfs2_holder mock_gh = { .gh_gl = gl, .gh_state = state, };
        unsigned long delay = 0;
        unsigned long holdtime;
        unsigned long now = jiffies;
@@ -1890,8 +1889,13 @@ void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
         * keep the glock until the last strong holder is done with it.
         */
        if (!find_first_strong_holder(gl)) {
-               if (state == LM_ST_UNLOCKED)
-                       mock_gh.gh_state = LM_ST_EXCLUSIVE;
+               struct gfs2_holder mock_gh = {
+                       .gh_gl = gl,
+                       .gh_state = (state == LM_ST_UNLOCKED) ?
+                                   LM_ST_EXCLUSIVE : state,
+                       .gh_iflags = BIT(HIF_HOLDER)
+               };
+
                demote_incompat_holders(gl, &mock_gh);
        }
        handle_callback(gl, state, delay, true);