gfs2: further simplify do_promote

This patch further simplifies function do_promote by eliminating some
redundant code in favor of using a lock_released flag. This is just
prep work for a future patch.

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

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index f9aebeba74546dadb28d23903e34329d810b6d9e..db213f0ef9605f0f244a72671f0fdfb03eec0b3c 100644 (file)
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -487,12 +487,14 @@ __acquires(&gl->gl_lockref.lock)
        const struct gfs2_glock_operations *glops = gl->gl_ops;
        struct gfs2_holder *gh, *tmp, *first_gh;
        bool incompat_holders_demoted = false;
+       bool lock_released;
        int ret;
 
 restart:
        first_gh = find_first_strong_holder(gl);
        list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
-               if (!test_bit(HIF_WAIT, &gh->gh_iflags))
+               lock_released = false;
+               if (test_bit(HIF_HOLDER, &gh->gh_iflags))
                        continue;
                if (!may_grant(gl, first_gh, gh)) {
                        /*
@@ -511,30 +513,31 @@ restart:
                        first_gh = gh;
                }
                if (gh->gh_list.prev == &gl->gl_holders &&
-                   glops->go_instantiate) {
-                       if (!(gh->gh_flags & GL_SKIP)) {
-                               spin_unlock(&gl->gl_lockref.lock);
-                               /* FIXME: eliminate this eventually */
-                               ret = glops->go_instantiate(gh);
-                               spin_lock(&gl->gl_lockref.lock);
-                               if (ret) {
-                                       if (ret == 1)
-                                               return 2;
-                                       gh->gh_error = ret;
-                                       list_del_init(&gh->gh_list);
-                                       trace_gfs2_glock_queue(gh, 0);
-                                       gfs2_holder_wake(gh);
-                                       goto restart;
-                               }
+                   !(gh->gh_flags & GL_SKIP) && glops->go_instantiate) {
+                       lock_released = true;
+                       spin_unlock(&gl->gl_lockref.lock);
+                       ret = glops->go_instantiate(gh);
+                       spin_lock(&gl->gl_lockref.lock);
+                       if (ret) {
+                               if (ret == 1)
+                                       return 2;
+                               gh->gh_error = ret;
+                               list_del_init(&gh->gh_list);
+                               trace_gfs2_glock_queue(gh, 0);
+                               gfs2_holder_wake(gh);
+                               goto restart;
                        }
-                       set_bit(HIF_HOLDER, &gh->gh_iflags);
-                       trace_gfs2_promote(gh);
-                       gfs2_holder_wake(gh);
-                       goto restart;
                }
                set_bit(HIF_HOLDER, &gh->gh_iflags);
                trace_gfs2_promote(gh);
                gfs2_holder_wake(gh);
+               /*
+                * If we released the gl_lockref.lock the holders list may have
+                * changed. For that reason, we start again at the start of
+                * the holders queue.
+                */
+               if (lock_released)
+                       goto restart;
        }
        return 0;
 }