[GFS2] Clean up the glock core

This patch implements a number of cleanups to the core of the
GFS2 glock code. As a result a lot of code is removed. It looks
like a really big change, but actually a large part of this patch
is either removing or moving existing code.

There are some new bits too though, such as the new run_queue()
function which is considerably streamlined. Highlights of this
patch include:

 o Fixes a cluster coherency bug during SH -> EX lock conversions
 o Removes the "glmutex" code in favour of a single bit lock
 o Removes the ->go_xmote_bh() for inodes since it was duplicating
   ->go_lock()
 o We now only use the ->lm_lock() function for both locks and
   unlocks (i.e. unlock is a lock with target mode LM_ST_UNLOCKED)
 o The fast path is considerably shortly, giving performance gains
   especially with lock_nolock
 o The glock_workqueue is now used for all the callbacks from the DLM
   which allows us to simplify the lock_dlm module (see following patch)
 o The way is now open to make further changes such as eliminating the two
   threads (gfs2_glockd and gfs2_scand) in favour of a more efficient
   scheme.

This patch has undergone extensive testing with various test suites
so it should be pretty stable by now.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Bob Peterson <rpeterso@redhat.com>

13 files changed, 736 insertions, 1049 deletions

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index d636b3e80f5..519a54cc0b7 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -45,21 +45,19 @@ struct gfs2_gl_hash_bucket {
         struct hlist_head hb_list;
 };
 
-struct glock_iter {
-	int hash;                     /* hash bucket index         */
-	struct gfs2_sbd *sdp;         /* incore superblock         */
-	struct gfs2_glock *gl;        /* current glock struct      */
-	struct seq_file *seq;         /* sequence file for debugfs */
-	char string[512];             /* scratch space             */
+struct gfs2_glock_iter {
+	int hash;			/* hash bucket index         */
+	struct gfs2_sbd *sdp;		/* incore superblock         */
+	struct gfs2_glock *gl;		/* current glock struct      */
+	char string[512];		/* scratch space             */
 };
 
 typedef void (*glock_examiner) (struct gfs2_glock * gl);
 
 static int gfs2_dump_lockstate(struct gfs2_sbd *sdp);
-static int dump_glock(struct glock_iter *gi, struct gfs2_glock *gl);
-static void gfs2_glock_xmote_th(struct gfs2_glock *gl, struct gfs2_holder *gh);
-static void gfs2_glock_drop_th(struct gfs2_glock *gl);
-static void run_queue(struct gfs2_glock *gl);
+static int __dump_glock(struct seq_file *seq, const struct gfs2_glock *gl);
+#define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) { __dump_glock(NULL, gl); BUG(); } } while(0)
+static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
 
 static DECLARE_RWSEM(gfs2_umount_flush_sem);
 static struct dentry *gfs2_root;
@@ -123,33 +121,6 @@ static inline rwlock_t *gl_lock_addr(unsigned int x)
 #endif
 
 /**
- * relaxed_state_ok - is a requested lock compatible with the current lock mode?
- * @actual: the current state of the lock
- * @requested: the lock state that was requested by the caller
- * @flags: the modifier flags passed in by the caller
- *
- * Returns: 1 if the locks are compatible, 0 otherwise
- */
-
-static inline int relaxed_state_ok(unsigned int actual, unsigned requested,
-				   int flags)
-{
-	if (actual == requested)
-		return 1;
-
-	if (flags & GL_EXACT)
-		return 0;
-
-	if (actual == LM_ST_EXCLUSIVE && requested == LM_ST_SHARED)
-		return 1;
-
-	if (actual != LM_ST_UNLOCKED && (flags & LM_FLAG_ANY))
-		return 1;
-
-	return 0;
-}
-
-/**
  * gl_hash() - Turn glock number into hash bucket number
  * @lock: The glock number
  *
@@ -211,17 +182,14 @@ static void gfs2_glock_hold(struct gfs2_glock *gl)
 int gfs2_glock_put(struct gfs2_glock *gl)
 {
 	int rv = 0;
-	struct gfs2_sbd *sdp = gl->gl_sbd;
 
 	write_lock(gl_lock_addr(gl->gl_hash));
 	if (atomic_dec_and_test(&gl->gl_ref)) {
 		hlist_del(&gl->gl_list);
 		write_unlock(gl_lock_addr(gl->gl_hash));
-		gfs2_assert(sdp, gl->gl_state == LM_ST_UNLOCKED);
-		gfs2_assert(sdp, list_empty(&gl->gl_reclaim));
-		gfs2_assert(sdp, list_empty(&gl->gl_holders));
-		gfs2_assert(sdp, list_empty(&gl->gl_waiters1));
-		gfs2_assert(sdp, list_empty(&gl->gl_waiters3));
+		GLOCK_BUG_ON(gl, gl->gl_state != LM_ST_UNLOCKED);
+		GLOCK_BUG_ON(gl, !list_empty(&gl->gl_reclaim));
+		GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
 		glock_free(gl);
 		rv = 1;
 		goto out;
@@ -281,16 +249,382 @@ static struct gfs2_glock *gfs2_glock_find(const struct gfs2_sbd *sdp,
 	return gl;
 }
 
+/**
+ * may_grant - check if its ok to grant a new lock
+ * @gl: The glock
+ * @gh: The lock request which we wish to grant
+ *
+ * Returns: true if its ok to grant the lock
+ */
+
+static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
+{
+	const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
+	if ((gh->gh_state == LM_ST_EXCLUSIVE ||
+	     gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
+		return 0;
+	if (gl->gl_state == gh->gh_state)
+		return 1;
+	if (gh->gh_flags & GL_EXACT)
+		return 0;
+	if (gh->gh_state == LM_ST_SHARED && gl->gl_state == LM_ST_EXCLUSIVE)
+		return 1;
+	if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY))
+		return 1;
+	return 0;
+}
+
+static void gfs2_holder_wake(struct gfs2_holder *gh)
+{
+	clear_bit(HIF_WAIT, &gh->gh_iflags);
+	smp_mb__after_clear_bit();
+	wake_up_bit(&gh->gh_iflags, HIF_WAIT);
+}
+
+/**
+ * do_promote - promote as many requests as possible on the current queue
+ * @gl: The glock
+ * 
+ * Returns: true if there is a blocked holder at the head of the list
+ */
+
+static int do_promote(struct gfs2_glock *gl)
+{
+	const struct gfs2_glock_operations *glops = gl->gl_ops;
+	struct gfs2_holder *gh, *tmp;
+	int ret;
+
+restart:
+	list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
+		if (test_bit(HIF_HOLDER, &gh->gh_iflags))
+			continue;
+		if (may_grant(gl, gh)) {
+			if (gh->gh_list.prev == &gl->gl_holders &&
+			    glops->go_lock) {
+				spin_unlock(&gl->gl_spin);
+				/* FIXME: eliminate this eventually */
+				ret = glops->go_lock(gh);
+				spin_lock(&gl->gl_spin);
+				if (ret) {
+					gh->gh_error = ret;
+					list_del_init(&gh->gh_list);
+					gfs2_holder_wake(gh);
+					goto restart;
+				}
+				set_bit(HIF_HOLDER, &gh->gh_iflags);
+				gfs2_holder_wake(gh);
+				goto restart;
+			}
+			set_bit(HIF_HOLDER, &gh->gh_iflags);
+			gfs2_holder_wake(gh);
+			continue;
+		}
+		if (gh->gh_list.prev == &gl->gl_holders)
+			return 1;
+		break;
+	}
+	return 0;
+}
+
+/**
+ * do_error - Something unexpected has happened during a lock request
+ *
+ */
+
+static inline void do_error(struct gfs2_glock *gl, const int ret)
+{
+	struct gfs2_holder *gh, *tmp;
+
+	list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
+		if (test_bit(HIF_HOLDER, &gh->gh_iflags))
+			continue;
+		if (ret & LM_OUT_ERROR)
+			gh->gh_error = -EIO;
+		else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
+			gh->gh_error = GLR_TRYFAILED;
+		else
+			continue;
+		list_del_init(&gh->gh_list);
+		gfs2_holder_wake(gh);
+	}
+}
+
+/**
+ * find_first_waiter - find the first gh that's waiting for the glock
+ * @gl: the glock
+ */
+
+static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
+{
+	struct gfs2_holder *gh;
+
+	list_for_each_entry(gh, &gl->gl_holders, gh_list) {
+		if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
+			return gh;
+	}
+	return NULL;
+}
+
+/**
+ * state_change - record that the glock is now in a different state
+ * @gl: the glock
+ * @new_state the new state
+ *
+ */
+
+static void state_change(struct gfs2_glock *gl, unsigned int new_state)
+{
+	int held1, held2;
+
+	held1 = (gl->gl_state != LM_ST_UNLOCKED);
+	held2 = (new_state != LM_ST_UNLOCKED);
+
+	if (held1 != held2) {
+		if (held2)
+			gfs2_glock_hold(gl);
+		else
+			gfs2_glock_put(gl);
+	}
+
+	gl->gl_state = new_state;
+	gl->gl_tchange = jiffies;
+}
+
+static void gfs2_demote_wake(struct gfs2_glock *gl)
+{
+	gl->gl_demote_state = LM_ST_EXCLUSIVE;
+	clear_bit(GLF_DEMOTE, &gl->gl_flags);
+	smp_mb__after_clear_bit();
+	wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
+}
+
+/**
+ * finish_xmote - The DLM has replied to one of our lock requests
+ * @gl: The glock
+ * @ret: The status from the DLM
+ *
+ */
+
+static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
+{
+	const struct gfs2_glock_operations *glops = gl->gl_ops;
+	struct gfs2_holder *gh;
+	unsigned state = ret & LM_OUT_ST_MASK;
+
+	spin_lock(&gl->gl_spin);
+	state_change(gl, state);
+	gh = find_first_waiter(gl);
+
+	/* Demote to UN request arrived during demote to SH or DF */
+	if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
+	    state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
+		gl->gl_target = LM_ST_UNLOCKED;
+
+	/* Check for state != intended state */
+	if (unlikely(state != gl->gl_target)) {
+		if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
+			/* move to back of queue and try next entry */
+			if (ret & LM_OUT_CANCELED) {
+				if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0)
+					list_move_tail(&gh->gh_list, &gl->gl_holders);
+				gh = find_first_waiter(gl);
+				gl->gl_target = gh->gh_state;
+				goto retry;
+			}
+			/* Some error or failed "try lock" - report it */
+			if ((ret & LM_OUT_ERROR) ||
+			    (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
+				gl->gl_target = gl->gl_state;
+				do_error(gl, ret);
+				goto out;
+			}
+		}
+		switch(state) {
+		/* Unlocked due to conversion deadlock, try again */
+		case LM_ST_UNLOCKED:
+retry:
+			do_xmote(gl, gh, gl->gl_target);
+			break;
+		/* Conversion fails, unlock and try again */
+		case LM_ST_SHARED:
+		case LM_ST_DEFERRED:
+			do_xmote(gl, gh, LM_ST_UNLOCKED);
+			break;
+		default: /* Everything else */
+			printk(KERN_ERR "GFS2: wanted %u got %u\n", gl->gl_target, state);
+			GLOCK_BUG_ON(gl, 1);
+		}
+		spin_unlock(&gl->gl_spin);
+		gfs2_glock_put(gl);
+		return;
+	}
+
+	/* Fast path - we got what we asked for */
+	if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
+		gfs2_demote_wake(gl);
+	if (state != LM_ST_UNLOCKED) {
+		if (glops->go_xmote_bh) {
+			int rv;
+			spin_unlock(&gl->gl_spin);
+			rv = glops->go_xmote_bh(gl, gh);
+			if (rv == -EAGAIN)
+				return;
+			spin_lock(&gl->gl_spin);
+			if (rv) {
+				do_error(gl, rv);
+				goto out;
+			}
+		}
+		do_promote(gl);
+	}
+out:
+	clear_bit(GLF_LOCK, &gl->gl_flags);
+	spin_unlock(&gl->gl_spin);
+	gfs2_glock_put(gl);
+}
+
+static unsigned int gfs2_lm_lock(struct gfs2_sbd *sdp, void *lock,
+				 unsigned int cur_state, unsigned int req_state,
+				 unsigned int flags)
+{
+	int ret = LM_OUT_ERROR;
+	if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+		ret = sdp->sd_lockstruct.ls_ops->lm_lock(lock, cur_state,
+							 req_state, flags);
+	return ret;
+}
+
+/**
+ * do_xmote - Calls the DLM to change the state of a lock
+ * @gl: The lock state
+ * @gh: The holder (only for promotes)
+ * @target: The target lock state
+ *
+ */
+
+static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
+{
+	const struct gfs2_glock_operations *glops = gl->gl_ops;
+	struct gfs2_sbd *sdp = gl->gl_sbd;
+	unsigned int lck_flags = gh ? gh->gh_flags : 0;
+	int ret;
+
+	lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
+		      LM_FLAG_PRIORITY);
+	BUG_ON(gl->gl_state == target);
+	BUG_ON(gl->gl_state == gl->gl_target);
+	if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
+	    glops->go_inval) {
+		set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
+		do_error(gl, 0); /* Fail queued try locks */
+	}
+	spin_unlock(&gl->gl_spin);
+	if (glops->go_xmote_th)
+		glops->go_xmote_th(gl);
+	if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
+		glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
+	clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
+
+	gfs2_glock_hold(gl);
+	if (target != LM_ST_UNLOCKED && (gl->gl_state == LM_ST_SHARED ||
+	    gl->gl_state == LM_ST_DEFERRED) &&
+	    !(lck_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
+		lck_flags |= LM_FLAG_TRY_1CB;
+	ret = gfs2_lm_lock(sdp, gl->gl_lock, gl->gl_state, target, lck_flags);
+
+	if (!(ret & LM_OUT_ASYNC)) {
+		finish_xmote(gl, ret);
+		gfs2_glock_hold(gl);
+		if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
+			gfs2_glock_put(gl);
+	} else {
+		GLOCK_BUG_ON(gl, ret != LM_OUT_ASYNC);
+	}
+	spin_lock(&gl->gl_spin);
+}
+
+/**
+ * find_first_holder - find the first "holder" gh
+ * @gl: the glock
+ */
+
+static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
+{
+	struct gfs2_holder *gh;
+
+	if (!list_empty(&gl->gl_holders)) {
+		gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
+		if (test_bit(HIF_HOLDER, &gh->gh_iflags))
+			return gh;
+	}
+	return NULL;
+}
+
+/**
+ * run_queue - do all outstanding tasks related to a glock
+ * @gl: The glock in question
+ * @nonblock: True if we must not block in run_queue
+ *
+ */
+
+static void run_queue(struct gfs2_glock *gl, const int nonblock)
+{
+	struct gfs2_holder *gh = NULL;
+
+	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) {
+		if (find_first_holder(gl))
+			goto out;
+		if (nonblock)
+			goto out_sched;
+		set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
+		gl->gl_target = gl->gl_demote_state;
+	} else {
+		if (test_bit(GLF_DEMOTE, &gl->gl_flags))
+			gfs2_demote_wake(gl);
+		if (do_promote(gl) == 0)
+			goto out;
+		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 */
+	}
+	do_xmote(gl, gh, gl->gl_target);
+	return;
+
+out_sched:
+	gfs2_glock_hold(gl);
+	if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
+		gfs2_glock_put(gl);
+out:
+	clear_bit(GLF_LOCK, &gl->gl_flags);
+}
+
 static void glock_work_func(struct work_struct *work)
 {
+	unsigned long delay = 0;
 	struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
 
+	if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags))
+		finish_xmote(gl, gl->gl_reply);
 	spin_lock(&gl->gl_spin);
-	if (test_and_clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags))
-		set_bit(GLF_DEMOTE, &gl->gl_flags);
-	run_queue(gl);
+	if (test_and_clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags)) {
+		unsigned long holdtime, now = jiffies;
+		holdtime = gl->gl_tchange + gl->gl_ops->go_min_hold_time;
+		if (time_before(now, holdtime))
+			delay = holdtime - now;
+		set_bit(delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE, &gl->gl_flags);
+	}
+	run_queue(gl, 0);
 	spin_unlock(&gl->gl_spin);
-	gfs2_glock_put(gl);
+	if (!delay ||
+	    queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
+		gfs2_glock_put(gl);
 }
 
 static int gfs2_lm_get_lock(struct gfs2_sbd *sdp, struct lm_lockname *name,
@@ -342,12 +676,10 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
 	gl->gl_name = name;
 	atomic_set(&gl->gl_ref, 1);
 	gl->gl_state = LM_ST_UNLOCKED;
+	gl->gl_target = LM_ST_UNLOCKED;
 	gl->gl_demote_state = LM_ST_EXCLUSIVE;
 	gl->gl_hash = hash;
-	gl->gl_owner_pid = NULL;
-	gl->gl_ip = 0;
 	gl->gl_ops = glops;
-	gl->gl_req_gh = NULL;
 	gl->gl_stamp = jiffies;
 	gl->gl_tchange = jiffies;
 	gl->gl_object = NULL;
@@ -447,13 +779,6 @@ void gfs2_holder_uninit(struct gfs2_holder *gh)
 	gh->gh_ip = 0;
 }
 
-static void gfs2_holder_wake(struct gfs2_holder *gh)
-{
-	clear_bit(HIF_WAIT, &gh->gh_iflags);
-	smp_mb__after_clear_bit();
-	wake_up_bit(&gh->gh_iflags, HIF_WAIT);
-}
-
 static int just_schedule(void *word)
 {
         schedule();
@@ -466,14 +791,6 @@ static void wait_on_holder(struct gfs2_holder *gh)
 	wait_on_bit(&gh->gh_iflags, HIF_WAIT, just_schedule, TASK_UNINTERRUPTIBLE);
 }
 
-static void gfs2_demote_wake(struct gfs2_glock *gl)
-{
-	gl->gl_demote_state = LM_ST_EXCLUSIVE;
-        clear_bit(GLF_DEMOTE, &gl->gl_flags);
-        smp_mb__after_clear_bit();
-        wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
-}
-
 static void wait_on_demote(struct gfs2_glock *gl)
 {
 	might_sleep();
@@ -481,217 +798,6 @@ static void wait_on_demote(struct gfs2_glock *gl)
 }
 
 /**
- * rq_mutex - process a mutex request in the queue
- * @gh: the glock holder
- *
- * Returns: 1 if the queue is blocked
- */
-
-static int rq_mutex(struct gfs2_holder *gh)
-{
-	struct gfs2_glock *gl = gh->gh_gl;
-
-	list_del_init(&gh->gh_list);
-	/*  gh->gh_error never examined.  */
-	set_bit(GLF_LOCK, &gl->gl_flags);
-	clear_bit(HIF_WAIT, &gh->gh_iflags);
-	smp_mb();
-	wake_up_bit(&gh->gh_iflags, HIF_WAIT);
-
-	return 1;
-}
-
-/**
- * rq_promote - process a promote request in the queue
- * @gh: the glock holder
- *
- * Acquire a new inter-node lock, or change a lock state to more restrictive.
- *
- * Returns: 1 if the queue is blocked
- */
-
-static int rq_promote(struct gfs2_holder *gh)
-{
-	struct gfs2_glock *gl = gh->gh_gl;
-
-	if (!relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
-		if (list_empty(&gl->gl_holders)) {
-			gl->gl_req_gh = gh;
-			set_bit(GLF_LOCK, &gl->gl_flags);
-			spin_unlock(&gl->gl_spin);
-			gfs2_glock_xmote_th(gh->gh_gl, gh);
-			spin_lock(&gl->gl_spin);
-		}
-		return 1;
-	}
-
-	if (list_empty(&gl->gl_holders)) {
-		set_bit(HIF_FIRST, &gh->gh_iflags);
-		set_bit(GLF_LOCK, &gl->gl_flags);
-	} else {
-		struct gfs2_holder *next_gh;
-		if (gh->gh_state == LM_ST_EXCLUSIVE)
-			return 1;
-		next_gh = list_entry(gl->gl_holders.next, struct gfs2_holder,
-				     gh_list);
-		if (next_gh->gh_state == LM_ST_EXCLUSIVE)
-			 return 1;
-	}
-
-	list_move_tail(&gh->gh_list, &gl->gl_holders);
-	gh->gh_error = 0;
-	set_bit(HIF_HOLDER, &gh->gh_iflags);
-
-	gfs2_holder_wake(gh);
-
-	return 0;
-}
-
-/**
- * rq_demote - process a demote request in the queue
- * @gh: the glock holder
- *
- * Returns: 1 if the queue is blocked
- */
-
-static int rq_demote(struct gfs2_glock *gl)
-{
-	if (!list_empty(&gl->gl_holders))
-		return 1;
-
-	if (gl->gl_state == gl->gl_demote_state ||
-	    gl->gl_state == LM_ST_UNLOCKED) {
-		gfs2_demote_wake(gl);
-		return 0;
-	}
-
-	set_bit(GLF_LOCK, &gl->gl_flags);
-	set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
-
-	if (gl->gl_demote_state == LM_ST_UNLOCKED ||
-	    gl->gl_state != LM_ST_EXCLUSIVE) {
-		spin_unlock(&gl->gl_spin);
-		gfs2_glock_drop_th(gl);
-	} else {
-		spin_unlock(&gl->gl_spin);
-		gfs2_glock_xmote_th(gl, NULL);
-	}
-
-	spin_lock(&gl->gl_spin);
-	clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
-
-	return 0;
-}
-
-/**
- * run_queue - process holder structures on a glock
- * @gl: the glock
- *
- */
-static void run_queue(struct gfs2_glock *gl)
-{
-	struct gfs2_holder *gh;
-	int blocked = 1;
-
-	for (;;) {
-		if (test_bit(GLF_LOCK, &gl->gl_flags))
-			break;
-
-		if (!list_empty(&gl->gl_waiters1)) {
-			gh = list_entry(gl->gl_waiters1.next,
-					struct gfs2_holder, gh_list);
-			blocked = rq_mutex(gh);
-		} else if (test_bit(GLF_DEMOTE, &gl->gl_flags)) {
-			blocked = rq_demote(gl);
-			if (test_bit(GLF_WAITERS2, &gl->gl_flags) &&
-				     !blocked) {
-				set_bit(GLF_DEMOTE, &gl->gl_flags);
-				gl->gl_demote_state = LM_ST_UNLOCKED;
-			}
-			clear_bit(GLF_WAITERS2, &gl->gl_flags);
-		} else if (!list_empty(&gl->gl_waiters3)) {
-			gh = list_entry(gl->gl_waiters3.next,
-					struct gfs2_holder, gh_list);
-			blocked = rq_promote(gh);
-		} else
-			break;
-
-		if (blocked)
-			break;
-	}
-}
-
-/**
- * gfs2_glmutex_lock - acquire a local lock on a glock
- * @gl: the glock
- *
- * Gives caller exclusive access to manipulate a glock structure.
- */
-
-static void gfs2_glmutex_lock(struct gfs2_glock *gl)
-{
-	spin_lock(&gl->gl_spin);
-	if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
-		struct gfs2_holder gh;
-
-		gfs2_holder_init(gl, 0, 0, &gh);
-		set_bit(HIF_WAIT, &gh.gh_iflags);
-		list_add_tail(&gh.gh_list, &gl->gl_waiters1);
-		spin_unlock(&gl->gl_spin);
-		wait_on_holder(&gh);
-		gfs2_holder_uninit(&gh);
-	} else {
-		gl->gl_owner_pid = get_pid(task_pid(current));
-		gl->gl_ip = (unsigned long)__builtin_return_address(0);
-		spin_unlock(&gl->gl_spin);
-	}
-}
-
-/**
- * gfs2_glmutex_trylock - try to acquire a local lock on a glock
- * @gl: the glock
- *
- * Returns: 1 if the glock is acquired
- */
-
-static int gfs2_glmutex_trylock(struct gfs2_glock *gl)
-{
-	int acquired = 1;
-
-	spin_lock(&gl->gl_spin);
-	if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
-		acquired = 0;
-	} else {
-		gl->gl_owner_pid = get_pid(task_pid(current));
-		gl->gl_ip = (unsigned long)__builtin_return_address(0);
-	}
-	spin_unlock(&gl->gl_spin);
-
-	return acquired;
-}
-
-/**
- * gfs2_glmutex_unlock - release a local lock on a glock
- * @gl: the glock
- *
- */
-
-static void gfs2_glmutex_unlock(struct gfs2_glock *gl)
-{
-	struct pid *pid;
-
-	spin_lock(&gl->gl_spin);
-	clear_bit(GLF_LOCK, &gl->gl_flags);
-	pid = gl->gl_owner_pid;
-	gl->gl_owner_pid = NULL;
-	gl->gl_ip = 0;
-	run_queue(gl);
-	spin_unlock(&gl->gl_spin);
-
-	put_pid(pid);
-}
-
-/**
  * handle_callback - process a demote request
  * @gl: the glock
  * @state: the state the caller wants us to change to
@@ -705,398 +811,45 @@ static void handle_callback(struct gfs2_glock *gl, unsigned int state,
 {
 	int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
 
-	spin_lock(&gl->gl_spin);
 	set_bit(bit, &gl->gl_flags);
 	if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
 		gl->gl_demote_state = state;
 		gl->gl_demote_time = jiffies;
 		if (remote && gl->gl_ops->go_type == LM_TYPE_IOPEN &&
-		    gl->gl_object) {
+		    gl->gl_object)
 			gfs2_glock_schedule_for_reclaim(gl);
-			spin_unlock(&gl->gl_spin);
-			return;
-		}
 	} else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
 			gl->gl_demote_state != state) {
-		if (test_bit(GLF_DEMOTE_IN_PROGRESS,  &gl->gl_flags)) 
-			set_bit(GLF_WAITERS2, &gl->gl_flags);
-		else 
-			gl->gl_demote_state = LM_ST_UNLOCKED;
+		gl->gl_demote_state = LM_ST_UNLOCKED;
 	}
-	spin_unlock(&gl->gl_spin);
 }
 
 /**
- * state_change - record that the glock is now in a different state
- * @gl: the glock
- * @new_state the new state
- *
- */
-
-static void state_change(struct gfs2_glock *gl, unsigned int new_state)
-{
-	int held1, held2;
-
-	held1 = (gl->gl_state != LM_ST_UNLOCKED);
-	held2 = (new_state != LM_ST_UNLOCKED);
-
-	if (held1 != held2) {
-		if (held2)
-			gfs2_glock_hold(gl);
-		else
-			gfs2_glock_put(gl);
-	}
-
-	gl->gl_state = new_state;
-	gl->gl_tchange = jiffies;
-}
-
-/**
- * drop_bh - Called after a lock module unlock completes
- * @gl: the glock
- * @ret: the return status
- *
- * Doesn't wake up the process waiting on the struct gfs2_holder (if any)
- * Doesn't drop the reference on the glock the top half took out
- *
- */
-
-static void drop_bh(struct gfs2_glock *gl, unsigned int ret)
-{
-	struct gfs2_sbd *sdp = gl->gl_sbd;
-	struct gfs2_holder *gh = gl->gl_req_gh;
-
-	gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
-	gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
-	gfs2_assert_warn(sdp, !ret);
-
-	state_change(gl, LM_ST_UNLOCKED);
-
-	if (test_and_clear_bit(GLF_CONV_DEADLK, &gl->gl_flags)) {
-		spin_lock(&gl->gl_spin);
-		gh->gh_error = 0;
-		spin_unlock(&gl->gl_spin);
-		gfs2_glock_xmote_th(gl, gl->gl_req_gh);
-		gfs2_glock_put(gl);
-		return;
-	}
-
-	spin_lock(&gl->gl_spin);
-	gfs2_demote_wake(gl);
-	clear_bit(GLF_LOCK, &gl->gl_flags);
-	spin_unlock(&gl->gl_spin);
-	gfs2_glock_put(gl);
-}
-
-/**
- * xmote_bh - Called after the lock module is done acquiring a lock
- * @gl: The glock in question
- * @ret: the int returned from the lock module
- *
- */
-
-static void xmote_bh(struct gfs2_glock *gl, unsigned int ret)
-{
-	struct gfs2_sbd *sdp = gl->gl_sbd;
-	const struct gfs2_glock_operations *glops = gl->gl_ops;
-	struct gfs2_holder *gh = gl->gl_req_gh;
-	int op_done = 1;
-
-	if (!gh && (ret & LM_OUT_ST_MASK) == LM_ST_UNLOCKED) {
-		drop_bh(gl, ret);
-		return;
-	}
-
-	gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
-	gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
-	gfs2_assert_warn(sdp, !(ret & LM_OUT_ASYNC));
-
-	state_change(gl, ret & LM_OUT_ST_MASK);
-
-	/*  Deal with each possible exit condition  */
-
-	if (!gh) {
-		gl->gl_stamp = jiffies;
-		if (ret & LM_OUT_CANCELED) {
-			op_done = 0;
-		} else {
-			spin_lock(&gl->gl_spin);
-			if (gl->gl_state != gl->gl_demote_state) {
-				spin_unlock(&gl->gl_spin);
-				gfs2_glock_drop_th(gl);
-				gfs2_glock_put(gl);
-				return;
-			}
-			gfs2_demote_wake(gl);
-			spin_unlock(&gl->gl_spin);
-		}
-	} else {
-		spin_lock(&gl->gl_spin);
-		if (ret & LM_OUT_CONV_DEADLK) {
-			gh->gh_error = 0;
-			set_bit(GLF_CONV_DEADLK, &gl->gl_flags);
-			spin_unlock(&gl->gl_spin);
-			gfs2_glock_drop_th(gl);
-			gfs2_glock_put(gl);
-			return;
-		}
-		list_del_init(&gh->gh_list);
-		gh->gh_error = -EIO;
-		if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) 
-			goto out;
-		gh->gh_error = GLR_CANCELED;
-		if (ret & LM_OUT_CANCELED) 
-			goto out;
-		if (relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
-			list_add_tail(&gh->gh_list, &gl->gl_holders);
-			gh->gh_error = 0;
-			set_bit(HIF_HOLDER, &gh->gh_iflags);
-			set_bit(HIF_FIRST, &gh->gh_iflags);
-			op_done = 0;
-			goto out;
-		}
-		gh->gh_error = GLR_TRYFAILED;
-		if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
-			goto out;
-		gh->gh_error = -EINVAL;
-		if (gfs2_assert_withdraw(sdp, 0) == -1)
-			fs_err(sdp, "ret = 0x%.8X\n", ret);
-out:
-		spin_unlock(&gl->gl_spin);
-	}
-
-	if (glops->go_xmote_bh)
-		glops->go_xmote_bh(gl);
-
-	if (op_done) {
-		spin_lock(&gl->gl_spin);
-		gl->gl_req_gh = NULL;
-		clear_bit(GLF_LOCK, &gl->gl_flags);
-		spin_unlock(&gl->gl_spin);
-	}
-
-	gfs2_glock_put(gl);
-
-	if (gh)
-		gfs2_holder_wake(gh);
-}
-
-static unsigned int gfs2_lm_lock(struct gfs2_sbd *sdp, void *lock,
-				 unsigned int cur_state, unsigned int req_state,
-				 unsigned int flags)
-{
-	int ret = 0;
-	if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
-		ret = sdp->sd_lockstruct.ls_ops->lm_lock(lock, cur_state,
-							 req_state, flags);
-	return ret;
-}
-
-/**
- * gfs2_glock_xmote_th - Call into the lock module to acquire or change a glock
- * @gl: The glock in question
- * @state: the requested state
- * @flags: modifier flags to the lock call
- *
- */
-
-static void gfs2_glock_xmote_th(struct gfs2_glock *gl, struct gfs2_holder *gh)
-{
-	struct gfs2_sbd *sdp = gl->gl_sbd;
-	int flags = gh ? gh->gh_flags : 0;
-	unsigned state = gh ? gh->gh_state : gl->gl_demote_state;
-	const struct gfs2_glock_operations *glops = gl->gl_ops;
-	int lck_flags = flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB |
-				 LM_FLAG_NOEXP | LM_FLAG_ANY |
-				 LM_FLAG_PRIORITY);
-	unsigned int lck_ret;
-
-	if (glops->go_xmote_th)
-		glops->go_xmote_th(gl);
-	if (state == LM_ST_DEFERRED && glops->go_inval)
-		glops->go_inval(gl, DIO_METADATA);
-
-	gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
-	gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
-	gfs2_assert_warn(sdp, state != LM_ST_UNLOCKED);
-	gfs2_assert_warn(sdp, state != gl->gl_state);
-
-	gfs2_glock_hold(gl);
-
-	lck_ret = gfs2_lm_lock(sdp, gl->gl_lock, gl->gl_state, state, lck_flags);
-
-	if (gfs2_assert_withdraw(sdp, !(lck_ret & LM_OUT_ERROR)))
-		return;
-
-	if (lck_ret & LM_OUT_ASYNC)
-		gfs2_assert_warn(sdp, lck_ret == LM_OUT_ASYNC);
-	else
-		xmote_bh(gl, lck_ret);
-}
-
-static unsigned int gfs2_lm_unlock(struct gfs2_sbd *sdp, void *lock,
-				   unsigned int cur_state)
-{
-	int ret = 0;
-	if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
-		ret =  sdp->sd_lockstruct.ls_ops->lm_unlock(lock, cur_state);
-	return ret;
-}
-
-/**
- * gfs2_glock_drop_th - call into the lock module to unlock a lock
- * @gl: the glock
- *
- */
-
-static void gfs2_glock_drop_th(struct gfs2_glock *gl)
-{
-	struct gfs2_sbd *sdp = gl->gl_sbd;
-	const struct gfs2_glock_operations *glops = gl->gl_ops;
-	unsigned int ret;
-
-	if (glops->go_xmote_th)
-		glops->go_xmote_th(gl);
-	if (glops->go_inval)
-		glops->go_inval(gl, DIO_METADATA);
-
-	gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
-	gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
-	gfs2_assert_warn(sdp, gl->gl_state != LM_ST_UNLOCKED);
-
-	gfs2_glock_hold(gl);
-
-	ret = gfs2_lm_unlock(sdp, gl->gl_lock, gl->gl_state);
-
-	if (gfs2_assert_withdraw(sdp, !(ret & LM_OUT_ERROR)))
-		return;
-
-	if (!ret)
-		drop_bh(gl, ret);
-	else
-		gfs2_assert_warn(sdp, ret == LM_OUT_ASYNC);
-}
-
-/**
- * do_cancels - cancel requests for locks stuck waiting on an expire flag
- * @gh: the LM_FLAG_PRIORITY holder waiting to acquire the lock
- *
- * Don't cancel GL_NOCANCEL requests.
- */
-
-static void do_cancels(struct gfs2_holder *gh)
-{
-	struct gfs2_glock *gl = gh->gh_gl;
-	struct gfs2_sbd *sdp = gl->gl_sbd;
-
-	spin_lock(&gl->gl_spin);
-
-	while (gl->gl_req_gh != gh &&
-	       !test_bit(HIF_HOLDER, &gh->gh_iflags) &&
-	       !list_empty(&gh->gh_list)) {
-		if (!(gl->gl_req_gh && (gl->gl_req_gh->gh_flags & GL_NOCANCEL))) {
-			spin_unlock(&gl->gl_spin);
-			if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
-				sdp->sd_lockstruct.ls_ops->lm_cancel(gl->gl_lock);
-			msleep(100);
-			spin_lock(&gl->gl_spin);
-		} else {
-			spin_unlock(&gl->gl_spin);
-			msleep(100);
-			spin_lock(&gl->gl_spin);
-		}
-	}
-
-	spin_unlock(&gl->gl_spin);
-}