Attachment 312577 Details for Bug 455940 – Another attempt at trying to work out whats going on

[patch] Another attempt at trying to work out whats going on

test4.diff (text/plain), 9.44 KB, created by Steve Whitehouse on 2008-07-24 16:12:54 UTC

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Creator: Steve Whitehouse

Created: 2008-07-24 16:12:54 UTC

Size: 9.44 KB

patch

obsolete

>diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
>index 4cbb695..81a5870 100644
>--- a/fs/gfs2/glock.c
>+++ b/fs/gfs2/glock.c
>@@ -397,9 +397,19 @@ static void state_change(struct gfs2_glock *gl, unsigned int new_state)
> static void gfs2_demote_wake(struct gfs2_glock *gl)
> {
> 	gl->gl_demote_state = LM_ST_EXCLUSIVE;
>-	clear_bit(GLF_DEMOTE, &gl->gl_flags);
>+	clear_bit(GLF_LOCAL_DEMOTE, &gl->gl_flags);
>+	clear_bit(GLF_REMOTE_DEMOTE, &gl->gl_flags);
> 	smp_mb__after_clear_bit();
>-	wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
>+	wake_up_bit(&gl->gl_flags, GLF_LOCAL_DEMOTE);
>+}
>+
>+static unsigned int gfs2_demote_target(const struct gfs2_glock *gl)
>+{
>+	if (test_bit(GLF_LOCAL_DEMOTE, &gl->gl_flags))
>+		return LM_ST_UNLOCKED;
>+	if (test_bit(GLF_REMOTE_DEMOTE, &gl->gl_flags))
>+		return gl->gl_demote_state;
>+	return LM_ST_EXCLUSIVE;
> }
> 
> /**
>@@ -420,9 +430,8 @@ static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
> 	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;
>+	if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
>+	    gl->gl_target = gfs2_demote_target(gl);
> 
> 	/* Check for state != intended state */
> 	if (unlikely(state != gl->gl_target)) {
>@@ -568,6 +577,14 @@ static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
> 	return NULL;
> }
> 
>+static int require_demote(const struct gfs2_glock *gl)
>+{
>+	unsigned long holdtime = gl->gl_tchange + gl->gl_ops->go_min_hold_time;
>+	return (test_bit(GLF_LOCAL_DEMOTE, &gl->gl_flags)) ||
>+	       (test_bit(GLF_REMOTE_DEMOTE, &gl->gl_flags) &&
>+		time_after(jiffies, holdtime));
>+}
>+
> /**
>  * run_queue - do all outstanding tasks related to a glock
>  * @gl: The glock in question
>@@ -584,20 +601,19 @@ static void run_queue(struct gfs2_glock *gl, const int nonblock)
> 
> 	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 (require_demote(gl)) {
> 		if (find_first_holder(gl))
> 			goto out;
> 		if (nonblock)
> 			goto out_sched;
> 		set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
>-		GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
>-		gl->gl_target = gl->gl_demote_state;
>+		gl->gl_target = gfs2_demote_target(gl);
>+		GLOCK_BUG_ON(gl, gl->gl_target == LM_ST_EXCLUSIVE);
> 	} else {
>-		if (test_bit(GLF_DEMOTE, &gl->gl_flags))
>-			gfs2_demote_wake(gl);
> 		if (do_promote(gl) == 0)
> 			goto out;
>+		if (test_bit(GLF_REMOTE_DEMOTE, &gl->gl_flags))
>+			goto out;
> 		gh = find_first_waiter(gl);
> 		gl->gl_target = gh->gh_state;
> 		if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
>@@ -617,21 +633,20 @@ out:
> static void glock_work_func(struct work_struct *work)
> {
> 	unsigned long delay = 0;
>+	unsigned long holdtime;
> 	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) &&
>-	    gl->gl_state != LM_ST_UNLOCKED &&
>-	    gl->gl_demote_state != LM_ST_EXCLUSIVE) {
>-		unsigned long holdtime, now = jiffies;
>+	run_queue(gl, 0);
>+	if (test_bit(GLF_REMOTE_DEMOTE, &gl->gl_flags)) {
>+		unsigned long now = jiffies;
> 		holdtime = gl->gl_tchange + gl->gl_ops->go_min_hold_time;
>+		delay = 1;
> 		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);
> 	if (!delay ||
> 	    queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
>@@ -807,34 +822,7 @@ static void wait_on_holder(struct gfs2_holder *gh)
> static void wait_on_demote(struct gfs2_glock *gl)
> {
> 	might_sleep();
>-	wait_on_bit(&gl->gl_flags, GLF_DEMOTE, just_schedule, TASK_UNINTERRUPTIBLE);
>-}
>-
>-/**
>- * handle_callback - process a demote request
>- * @gl: the glock
>- * @state: the state the caller wants us to change to
>- *
>- * There are only two requests that we are going to see in actual
>- * practise: LM_ST_SHARED and LM_ST_UNLOCKED
>- */
>-
>-static void handle_callback(struct gfs2_glock *gl, unsigned int state,
>-			    int remote, unsigned long delay)
>-{
>-	int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
>-
>-	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)
>-			gfs2_glock_schedule_for_reclaim(gl);
>-	} else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
>-			gl->gl_demote_state != state) {
>-		gl->gl_demote_state = LM_ST_UNLOCKED;
>-	}
>+	wait_on_bit(&gl->gl_flags, GLF_LOCAL_DEMOTE, just_schedule, TASK_UNINTERRUPTIBLE);
> }
> 
> /**
>@@ -998,7 +986,7 @@ void gfs2_glock_dq(struct gfs2_holder *gh)
> 
> 	spin_lock(&gl->gl_spin);
> 	if (gh->gh_flags & GL_NOCACHE)
>-		handle_callback(gl, LM_ST_UNLOCKED, 0, 0);
>+		set_bit(GLF_LOCAL_DEMOTE, &gl->gl_flags);
> 
> 	list_del_init(&gh->gh_list);
> 	if (find_first_holder(gl) == NULL) {
>@@ -1011,8 +999,8 @@ void gfs2_glock_dq(struct gfs2_holder *gh)
> 		}
> 		gl->gl_stamp = jiffies;
> 		if (list_empty(&gl->gl_holders) &&
>-		    !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
>-		    !test_bit(GLF_DEMOTE, &gl->gl_flags))
>+		    !test_bit(GLF_REMOTE_DEMOTE, &gl->gl_flags) &&
>+		    !test_bit(GLF_LOCAL_DEMOTE, &gl->gl_flags))
> 			fast_path = 1;
> 	}
> 	spin_unlock(&gl->gl_spin);
>@@ -1020,8 +1008,8 @@ void gfs2_glock_dq(struct gfs2_holder *gh)
> 		return;
> 
> 	gfs2_glock_hold(gl);
>-	if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
>-	    !test_bit(GLF_DEMOTE, &gl->gl_flags))
>+	if (test_bit(GLF_REMOTE_DEMOTE, &gl->gl_flags) &&
>+	    !test_bit(GLF_LOCAL_DEMOTE, &gl->gl_flags))
> 		delay = gl->gl_ops->go_min_hold_time;
> 	if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
> 		gfs2_glock_put(gl);
>@@ -1267,7 +1255,15 @@ static void blocking_cb(struct gfs2_sbd *sdp, struct lm_lockname *name,
> 		delay = holdtime - now;
> 
> 	spin_lock(&gl->gl_spin);
>-	handle_callback(gl, state, 1, delay);
>+	if (!test_and_set_bit(GLF_REMOTE_DEMOTE, &gl->gl_flags)) {
>+		gl->gl_demote_time = now;
>+		GLOCK_BUG_ON(gl, gl->gl_demote_state != LM_ST_EXCLUSIVE);
>+		gl->gl_demote_state = state;
>+		if (gl->gl_ops->go_type == LM_TYPE_IOPEN && gl->gl_object)
>+			gfs2_glock_schedule_for_reclaim(gl);
>+	} else if (gl->gl_demote_state != state) {
>+		gl->gl_demote_state = LM_ST_UNLOCKED;
>+	}
> 	spin_unlock(&gl->gl_spin);
> 	if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
> 		gfs2_glock_put(gl);
>@@ -1401,7 +1397,7 @@ void gfs2_reclaim_glock(struct gfs2_sbd *sdp)
> 	spin_lock(&gl->gl_spin);
> 	if (find_first_holder(gl) == NULL &&
> 	    gl->gl_state != LM_ST_UNLOCKED && demote_ok(gl)) {
>-		handle_callback(gl, LM_ST_UNLOCKED, 0, 0);
>+		set_bit(GLF_LOCAL_DEMOTE, &gl->gl_flags);
> 		done_callback = 1;
> 	}
> 	spin_unlock(&gl->gl_spin);
>@@ -1498,7 +1494,7 @@ static void clear_glock(struct gfs2_glock *gl)
> 
> 	spin_lock(&gl->gl_spin);
> 	if (find_first_holder(gl) == NULL && gl->gl_state != LM_ST_UNLOCKED)
>-		handle_callback(gl, LM_ST_UNLOCKED, 0, 0);
>+		set_bit(GLF_LOCAL_DEMOTE, &gl->gl_flags);
> 	spin_unlock(&gl->gl_spin);
> 	gfs2_glock_hold(gl);
> 	if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
>@@ -1625,9 +1621,9 @@ static const char *gflags2str(char *buf, const unsigned long *gflags)
> 		*p++ = 'l';
> 	if (test_bit(GLF_STICKY, gflags))
> 		*p++ = 's';
>-	if (test_bit(GLF_DEMOTE, gflags))
>+	if (test_bit(GLF_LOCAL_DEMOTE, gflags))
> 		*p++ = 'D';
>-	if (test_bit(GLF_PENDING_DEMOTE, gflags))
>+	if (test_bit(GLF_REMOTE_DEMOTE, gflags))
> 		*p++ = 'd';
> 	if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
> 		*p++ = 'p';
>@@ -1671,7 +1667,7 @@ static int __dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
> 
> 	dtime = jiffies - gl->gl_demote_time;
> 	dtime *= 1000000/HZ; /* demote time in uSec */
>-	if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
>+	if (!test_bit(GLF_REMOTE_DEMOTE, &gl->gl_flags))
> 		dtime = 0;
> 	gfs2_print_dbg(seq, "G:  s:%s n:%u/%llu f:%s t:%s d:%s/%llu l:%d a:%d r:%d\n",
> 		  state2str(gl->gl_state),
>diff --git a/fs/gfs2/glock.h b/fs/gfs2/glock.h
>index 971d92a..930a6c3 100644
>--- a/fs/gfs2/glock.h
>+++ b/fs/gfs2/glock.h
>@@ -67,11 +67,8 @@ static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl)
> 
> static inline int gfs2_glock_is_blocking(struct gfs2_glock *gl)
> {
>-	int ret;
>-	spin_lock(&gl->gl_spin);
>-	ret = test_bit(GLF_DEMOTE, &gl->gl_flags);
>-	spin_unlock(&gl->gl_spin);
>-	return ret;
>+	return test_bit(GLF_LOCAL_DEMOTE, &gl->gl_flags) ||
>+	       test_bit(GLF_REMOTE_DEMOTE, &gl->gl_flags);
> }
> 
> int gfs2_glock_get(struct gfs2_sbd *sdp,
>diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
>index 448697a..ee787e1 100644
>--- a/fs/gfs2/incore.h
>+++ b/fs/gfs2/incore.h
>@@ -160,8 +160,8 @@ struct gfs2_holder {
> enum {
> 	GLF_LOCK			= 1,
> 	GLF_STICKY			= 2,
>-	GLF_DEMOTE			= 3,
>-	GLF_PENDING_DEMOTE		= 4,
>+	GLF_LOCAL_DEMOTE		= 3,
>+	GLF_REMOTE_DEMOTE		= 4,
> 	GLF_DEMOTE_IN_PROGRESS		= 5,
> 	GLF_DIRTY			= 6,
> 	GLF_LFLUSH			= 7,
>diff --git a/fs/gfs2/ops_super.c b/fs/gfs2/ops_super.c
>index f66ea0f..9e47e34 100644
>--- a/fs/gfs2/ops_super.c
>+++ b/fs/gfs2/ops_super.c
>@@ -301,7 +301,7 @@ static void gfs2_drop_inode(struct inode *inode)
> 
> 	if (test_bit(GIF_USER, &ip->i_flags) && inode->i_nlink) {
> 		struct gfs2_glock *gl = ip->i_iopen_gh.gh_gl;
>-		if (gl && test_bit(GLF_DEMOTE, &gl->gl_flags))
>+		if (gl && test_bit(GLF_REMOTE_DEMOTE, &gl->gl_flags))
> 			clear_nlink(inode);
> 	}
> 	generic_drop_inode(inode);

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Attachments on bug 455940: 312277 | 312369 | 312492 | 312577 | 312596 | 312646 | 312657