[Cluster-devel] [PATCH 08/13] GFS2: Add a new GL_ST_PROMOTE state to glock state machine

[Bob Peterson]

Before this patch, function run_queue did a bunch of logic when
glocks are being promoted. This patch moves the logic to the glock
state machine and simplifies run_queue further.

Signed-off-by: Bob Peterson <rpete...@redhat.com>
---
 fs/gfs2/glock.c | 46 +++++++++++++++++++++++-----------------------
 fs/gfs2/glock.h |  1 +
 2 files changed, 24 insertions(+), 23 deletions(-)

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 023e2186b374..6048867b2d66 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -621,37 +621,17 @@ static void run_queue(struct gfs2_glock *gl, const int 
nonblock)
 __releases(&gl->gl_lockref.lock)
 __acquires(&gl->gl_lockref.lock)
 {
-       struct gfs2_holder *gh = NULL;
-       int ret;
-
        if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
                return;
 
        GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
 
        if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
-           gl->gl_demote_state != gl->gl_state) {
+           gl->gl_demote_state != gl->gl_state)
                __state_machine(gl, nonblock ? GL_ST_DEMOTE_NONBLOCK :
                                GL_ST_BLOCKING_DEMOTE);
-               return;
-       } else {
-               if (test_bit(GLF_DEMOTE, &gl->gl_flags))
-                       gfs2_demote_wake(gl);
-               ret = do_promote(gl);
-               if (ret == 0) {
-                       clear_bit(GLF_LOCK, &gl->gl_flags);
-                       smp_mb__after_atomic();
-                       return;
-               }
-               if (ret == 2)
-                       return;
-               gh = find_first_waiter(gl);
-               gl->gl_target = gh->gh_state;
-               if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
-                       do_error(gl, 0); /* Fail queued try locks */
-       }
-       __state_machine(gl, GL_ST_DO_XMOTE);
-       return;
+       else
+               __state_machine(gl, GL_ST_PROMOTE);
 }
 
 /**
@@ -668,6 +648,7 @@ __acquires(&gl->gl_lockref.lock)
  */
 static void __state_machine(struct gfs2_glock *gl, int new_state)
 {
+       struct gfs2_holder *gh = NULL;
        int ret;
 
        BUG_ON(!spin_is_locked(&gl->gl_lockref.lock));
@@ -727,6 +708,25 @@ static void __state_machine(struct gfs2_glock *gl, int 
new_state)
                        gl->gl_lockref.count++;
                        __gfs2_glock_queue_work(gl, 0);
                        break;
+
+               case GL_ST_PROMOTE:
+                       gl->gl_mch = GL_ST_IDLE;
+                       if (test_bit(GLF_DEMOTE, &gl->gl_flags))
+                               gfs2_demote_wake(gl);
+                       ret = do_promote(gl);
+                       if (ret == 0) {
+                               clear_bit(GLF_LOCK, &gl->gl_flags);
+                               smp_mb__after_atomic();
+                               break;
+                       }
+                       if (ret == 2)
+                               break;
+                       gh = find_first_waiter(gl);
+                       gl->gl_target = gh->gh_state;
+                       if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
+                               do_error(gl, 0); /* Fail queued try locks */
+                       gl->gl_mch = GL_ST_DO_XMOTE;
+                       break;
                }
        } while (gl->gl_mch != GL_ST_IDLE);
 }
diff --git a/fs/gfs2/glock.h b/fs/gfs2/glock.h
index c8b704a73638..76db63d1efae 100644
--- a/fs/gfs2/glock.h
+++ b/fs/gfs2/glock.h
@@ -128,6 +128,7 @@ enum gl_machine_states {
                                      state change attempt from dlm. */
        GL_ST_DEMOTE_NONBLOCK = 4, /* Demote is in progress - non-blocking */
        GL_ST_BLOCKING_DEMOTE = 5, /* Demote is in progress - blocking */
+       GL_ST_PROMOTE = 6,         /* Promote the lock */
 };
 
 struct lm_lockops {
-- 
2.19.1