1 files changed, 353 insertions, 162 deletions

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 44a7a4288956..df335c258eb0 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -33,6 +33,9 @@
 #include <linux/list_sort.h>
 #include <linux/lockref.h>
 #include <linux/rhashtable.h>
+#include <linux/pid_namespace.h>
+#include <linux/fdtable.h>
+#include <linux/file.h>
 
 #include "gfs2.h"
 #include "incore.h"
@@ -59,6 +62,8 @@ typedef void (*glock_examiner) (struct gfs2_glock * gl);
 
 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
 static void __gfs2_glock_dq(struct gfs2_holder *gh);
+static void handle_callback(struct gfs2_glock *gl, unsigned int state,
+			    unsigned long delay, bool remote);
 
 static struct dentry *gfs2_root;
 static struct workqueue_struct *glock_workqueue;
@@ -127,9 +132,11 @@ static void gfs2_glock_dealloc(struct rcu_head *rcu)
 	struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
 
 	kfree(gl->gl_lksb.sb_lvbptr);
-	if (gl->gl_ops->go_flags & GLOF_ASPACE)
-		kmem_cache_free(gfs2_glock_aspace_cachep, gl);
-	else
+	if (gl->gl_ops->go_flags & GLOF_ASPACE) {
+		struct gfs2_glock_aspace *gla =
+			container_of(gl, struct gfs2_glock_aspace, glock);
+		kmem_cache_free(gfs2_glock_aspace_cachep, gla);
+	} else
 		kmem_cache_free(gfs2_glock_cachep, gl);
 }
 
@@ -301,9 +308,6 @@ void gfs2_glock_queue_put(struct gfs2_glock *gl)
 
 void gfs2_glock_put(struct gfs2_glock *gl)
 {
-	/* last put could call sleepable dlm api */
-	might_sleep();
-
 	if (lockref_put_or_lock(&gl->gl_lockref))
 		return;
 
@@ -406,10 +410,13 @@ static void do_error(struct gfs2_glock *gl, const int ret)
 /**
  * demote_incompat_holders - demote incompatible demoteable holders
  * @gl: the glock we want to promote
- * @new_gh: the new holder to be promoted
+ * @current_gh: the newly promoted holder
+ *
+ * We're passing the newly promoted holder in @current_gh, but actually, any of
+ * the strong holders would do.
  */
 static void demote_incompat_holders(struct gfs2_glock *gl,
-				    struct gfs2_holder *new_gh)
+				    struct gfs2_holder *current_gh)
 {
 	struct gfs2_holder *gh, *tmp;
 
@@ -425,8 +432,10 @@ static void demote_incompat_holders(struct gfs2_glock *gl,
 		 */
 		if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
 			return;
+		if (gh == current_gh)
+			continue;
 		if (test_bit(HIF_MAY_DEMOTE, &gh->gh_iflags) &&
-		    !may_grant(gl, new_gh, gh)) {
+		    !may_grant(gl, current_gh, gh)) {
 			/*
 			 * We should not recurse into do_promote because
 			 * __gfs2_glock_dq only calls handle_callback,
@@ -477,10 +486,9 @@ find_first_strong_holder(struct gfs2_glock *gl)
 
 /*
  * gfs2_instantiate - Call the glops instantiate function
- * @gl: The glock
+ * @gh: The glock holder
  *
- * Returns: 0 if instantiate was successful, 2 if type specific operation is
- * underway, or error.
+ * Returns: 0 if instantiate was successful, or error.
  */
 int gfs2_instantiate(struct gfs2_holder *gh)
 {
@@ -490,7 +498,7 @@ int gfs2_instantiate(struct gfs2_holder *gh)
 
 again:
 	if (!test_bit(GLF_INSTANTIATE_NEEDED, &gl->gl_flags))
-		return 0;
+		goto done;
 
 	/*
 	 * Since we unlock the lockref lock, we set a flag to indicate
@@ -509,78 +517,55 @@ again:
 		goto again;
 	}
 
-	ret = glops->go_instantiate(gh);
+	ret = glops->go_instantiate(gl);
 	if (!ret)
 		clear_bit(GLF_INSTANTIATE_NEEDED, &gl->gl_flags);
 	clear_and_wake_up_bit(GLF_INSTANTIATE_IN_PROG, &gl->gl_flags);
-	return ret;
+	if (ret)
+		return ret;
+
+done:
+	if (glops->go_held)
+		return glops->go_held(gh);
+	return 0;
 }
 
 /**
  * do_promote - promote as many requests as possible on the current queue
  * @gl: The glock
  * 
- * Returns: 1 if there is a blocked holder at the head of the list, or 2
- *          if a type specific operation is underway.
+ * Returns: 1 if there is a blocked holder at the head of the list
  */
 
 static int do_promote(struct gfs2_glock *gl)
-__releases(&gl->gl_lockref.lock)
-__acquires(&gl->gl_lockref.lock)
 {
-	struct gfs2_holder *gh, *tmp, *first_gh;
+	struct gfs2_holder *gh, *current_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) {
-		lock_released = false;
+	current_gh = find_first_strong_holder(gl);
+	list_for_each_entry(gh, &gl->gl_holders, gh_list) {
 		if (test_bit(HIF_HOLDER, &gh->gh_iflags))
 			continue;
-		if (!may_grant(gl, first_gh, gh)) {
+		if (!may_grant(gl, current_gh, gh)) {
 			/*
-			 * If we get here, it means we may not grant this holder for
-			 * some reason. If this holder is the head of the list, it
-			 * means we have a blocked holder at the head, so return 1.
+			 * If we get here, it means we may not grant this
+			 * holder for some reason. If this holder is at the
+			 * head of the list, it means we have a blocked holder
+			 * at the head, so return 1.
 			 */
-			if (gh->gh_list.prev == &gl->gl_holders)
+			if (list_is_first(&gh->gh_list, &gl->gl_holders))
 				return 1;
 			do_error(gl, 0);
 			break;
 		}
-		if (!incompat_holders_demoted) {
-			demote_incompat_holders(gl, first_gh);
-			incompat_holders_demoted = true;
-			first_gh = gh;
-		}
-		if (test_bit(GLF_INSTANTIATE_NEEDED, &gl->gl_flags) &&
-		    !(gh->gh_flags & GL_SKIP) && gl->gl_ops->go_instantiate) {
-			lock_released = true;
-			spin_unlock(&gl->gl_lockref.lock);
-			ret = gfs2_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);
-		/*
-		 * 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;
+		if (!incompat_holders_demoted) {
+			current_gh = gh;
+			demote_incompat_holders(gl, current_gh);
+			incompat_holders_demoted = true;
+		}
 	}
 	return 0;
 }
@@ -658,7 +643,6 @@ 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;
-	int rv;
 
 	spin_lock(&gl->gl_lockref.lock);
 	trace_gfs2_glock_state_change(gl, state);
@@ -672,6 +656,8 @@ static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
 
 	/* Check for state != intended state */
 	if (unlikely(state != gl->gl_target)) {
+		if (gh && (ret & LM_OUT_CANCELED))
+			gfs2_holder_wake(gh);
 		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) {
@@ -714,6 +700,8 @@ retry:
 		gfs2_demote_wake(gl);
 	if (state != LM_ST_UNLOCKED) {
 		if (glops->go_xmote_bh) {
+			int rv;
+
 			spin_unlock(&gl->gl_lockref.lock);
 			rv = glops->go_xmote_bh(gl);
 			spin_lock(&gl->gl_lockref.lock);
@@ -722,13 +710,10 @@ retry:
 				goto out;
 			}
 		}
-		rv = do_promote(gl);
-		if (rv == 2)
-			goto out_locked;
+		do_promote(gl);
 	}
 out:
 	clear_bit(GLF_LOCK, &gl->gl_flags);
-out_locked:
 	spin_unlock(&gl->gl_lockref.lock);
 }
 
@@ -750,7 +735,8 @@ static bool is_system_glock(struct gfs2_glock *gl)
  *
  */
 
-static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
+static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh,
+					 unsigned int target)
 __releases(&gl->gl_lockref.lock)
 __acquires(&gl->gl_lockref.lock)
 {
@@ -761,7 +747,8 @@ __acquires(&gl->gl_lockref.lock)
 
 	if (target != LM_ST_UNLOCKED && glock_blocked_by_withdraw(gl) &&
 	    gh && !(gh->gh_flags & LM_FLAG_NOEXP))
-		return;
+		goto skip_inval;
+
 	lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
 		      LM_FLAG_PRIORITY);
 	GLOCK_BUG_ON(gl, gl->gl_state == target);
@@ -846,6 +833,20 @@ skip_inval:
 	    (target != LM_ST_UNLOCKED ||
 	     test_bit(SDF_WITHDRAW_RECOVERY, &sdp->sd_flags))) {
 		if (!is_system_glock(gl)) {
+			handle_callback(gl, LM_ST_UNLOCKED, 0, false); /* sets demote */
+			/*
+			 * Ordinarily, we would call dlm and its callback would call
+			 * finish_xmote, which would call state_change() to the new state.
+			 * Since we withdrew, we won't call dlm, so call state_change
+			 * manually, but to the UNLOCKED state we desire.
+			 */
+			state_change(gl, LM_ST_UNLOCKED);
+			/*
+			 * We skip telling dlm to do the locking, so we won't get a
+			 * reply that would otherwise clear GLF_LOCK. So we clear it here.
+			 */
+			clear_bit(GLF_LOCK, &gl->gl_flags);
+			clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
 			gfs2_glock_queue_work(gl, GL_GLOCK_DFT_HOLD);
 			goto out;
 		} else {
@@ -885,7 +886,6 @@ __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;
@@ -904,18 +904,14 @@ __acquires(&gl->gl_lockref.lock)
 	} else {
 		if (test_bit(GLF_DEMOTE, &gl->gl_flags))
 			gfs2_demote_wake(gl);
-		ret = do_promote(gl);
-		if (ret == 0)
+		if (do_promote(gl) == 0)
 			goto out_unlock;
-		if (ret == 2)
-			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);
-out:
 	return;
 
 out_sched:
@@ -1043,16 +1039,18 @@ static void delete_work_func(struct work_struct *work)
 			if (gfs2_queue_delete_work(gl, 5 * HZ))
 				return;
 		}
-		goto out;
 	}
 
 	inode = gfs2_lookup_by_inum(sdp, no_addr, gl->gl_no_formal_ino,
 				    GFS2_BLKST_UNLINKED);
-	if (!IS_ERR_OR_NULL(inode)) {
+	if (IS_ERR(inode)) {
+		if (PTR_ERR(inode) == -EAGAIN &&
+			(gfs2_queue_delete_work(gl, 5 * HZ)))
+				return;
+	} else {
 		d_prune_aliases(inode);
 		iput(inode);
 	}
-out:
 	gfs2_glock_put(gl);
 }
 
@@ -1160,7 +1158,6 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
 				    .ln_sbd = sdp };
 	struct gfs2_glock *gl, *tmp;
 	struct address_space *mapping;
-	struct kmem_cache *cachep;
 	int ret = 0;
 
 	gl = find_insert_glock(&name, NULL);
@@ -1171,20 +1168,24 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
 	if (!create)
 		return -ENOENT;
 
-	if (glops->go_flags & GLOF_ASPACE)
-		cachep = gfs2_glock_aspace_cachep;
-	else
-		cachep = gfs2_glock_cachep;
-	gl = kmem_cache_alloc(cachep, GFP_NOFS);
-	if (!gl)
-		return -ENOMEM;
-
+	if (glops->go_flags & GLOF_ASPACE) {
+		struct gfs2_glock_aspace *gla =
+			kmem_cache_alloc(gfs2_glock_aspace_cachep, GFP_NOFS);
+		if (!gla)
+			return -ENOMEM;
+		gl = &gla->glock;
+	} else {
+		gl = kmem_cache_alloc(gfs2_glock_cachep, GFP_NOFS);
+		if (!gl)
+			return -ENOMEM;
+	}
 	memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
+	gl->gl_ops = glops;
 
 	if (glops->go_flags & GLOF_LVB) {
 		gl->gl_lksb.sb_lvbptr = kzalloc(GDLM_LVB_SIZE, GFP_NOFS);
 		if (!gl->gl_lksb.sb_lvbptr) {
-			kmem_cache_free(cachep, gl);
+			gfs2_glock_dealloc(&gl->gl_rcu);
 			return -ENOMEM;
 		}
 	}
@@ -1198,7 +1199,6 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
 	gl->gl_state = LM_ST_UNLOCKED;
 	gl->gl_target = LM_ST_UNLOCKED;
 	gl->gl_demote_state = LM_ST_EXCLUSIVE;
-	gl->gl_ops = glops;
 	gl->gl_dstamp = 0;
 	preempt_disable();
 	/* We use the global stats to estimate the initial per-glock stats */
@@ -1235,8 +1235,7 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
 	*glp = tmp;
 
 out_free:
-	kfree(gl->gl_lksb.sb_lvbptr);
-	kmem_cache_free(cachep, gl);
+	gfs2_glock_dealloc(&gl->gl_rcu);
 	if (atomic_dec_and_test(&sdp->sd_glock_disposal))
 		wake_up(&sdp->sd_glock_wait);
 
@@ -1245,7 +1244,7 @@ out:
 }
 
 /**
- * gfs2_holder_init - initialize a struct gfs2_holder in the default way
+ * __gfs2_holder_init - initialize a struct gfs2_holder in the default way
  * @gl: the glock
  * @state: the state we're requesting
  * @flags: the modifier flags
@@ -1262,7 +1261,6 @@ void __gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, u16 flags,
 	gh->gh_owner_pid = get_pid(task_pid(current));
 	gh->gh_state = state;
 	gh->gh_flags = flags;
-	gh->gh_error = 0;
 	gh->gh_iflags = 0;
 	gfs2_glock_hold(gl);
 }
@@ -1313,6 +1311,25 @@ static void gfs2_glock_update_hold_time(struct gfs2_glock *gl,
 }
 
 /**
+ * gfs2_glock_holder_ready - holder is ready and its error code can be collected
+ * @gh: the glock holder
+ *
+ * Called when a glock holder no longer needs to be waited for because it is
+ * now either held (HIF_HOLDER set; gh_error == 0), or acquiring the lock has
+ * failed (gh_error != 0).
+ */
+
+int gfs2_glock_holder_ready(struct gfs2_holder *gh)
+{
+	if (gh->gh_error || (gh->gh_flags & GL_SKIP))
+		return gh->gh_error;
+	gh->gh_error = gfs2_instantiate(gh);
+	if (gh->gh_error)
+		gfs2_glock_dq(gh);
+	return gh->gh_error;
+}
+
+/**
  * gfs2_glock_wait - wait on a glock acquisition
  * @gh: the glock holder
  *
@@ -1326,7 +1343,7 @@ int gfs2_glock_wait(struct gfs2_holder *gh)
 	might_sleep();
 	wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE);
 	gfs2_glock_update_hold_time(gh->gh_gl, start_time);
-	return gh->gh_error;
+	return gfs2_glock_holder_ready(gh);
 }
 
 static int glocks_pending(unsigned int num_gh, struct gfs2_holder *ghs)
@@ -1354,7 +1371,6 @@ int gfs2_glock_async_wait(unsigned int num_gh, struct gfs2_holder *ghs)
 	struct gfs2_sbd *sdp = ghs[0].gh_gl->gl_name.ln_sbd;
 	int i, ret = 0, timeout = 0;
 	unsigned long start_time = jiffies;
-	bool keep_waiting;
 
 	might_sleep();
 	/*
@@ -1364,53 +1380,33 @@ int gfs2_glock_async_wait(unsigned int num_gh, struct gfs2_holder *ghs)
 	for (i = 0; i < num_gh; i++)
 		timeout += ghs[i].gh_gl->gl_hold_time << 1;
 
-wait_for_dlm:
 	if (!wait_event_timeout(sdp->sd_async_glock_wait,
-				!glocks_pending(num_gh, ghs), timeout))
+				!glocks_pending(num_gh, ghs), timeout)) {
 		ret = -ESTALE; /* request timed out. */
+		goto out;
+	}
 
-	/*
-	 * If dlm granted all our requests, we need to adjust the glock
-	 * minimum hold time values according to how long we waited.
-	 *
-	 * If our request timed out, we need to repeatedly release any held
-	 * glocks we acquired thus far to allow dlm to acquire the remaining
-	 * glocks without deadlocking.  We cannot currently cancel outstanding
-	 * glock acquisitions.
-	 *
-	 * The HIF_WAIT bit tells us which requests still need a response from
-	 * dlm.
-	 *
-	 * If dlm sent us any errors, we return the first error we find.
-	 */
-	keep_waiting = false;
 	for (i = 0; i < num_gh; i++) {
-		/* Skip holders we have already dequeued below. */
-		if (!gfs2_holder_queued(&ghs[i]))
-			continue;
-		/* Skip holders with a pending DLM response. */
-		if (test_bit(HIF_WAIT, &ghs[i].gh_iflags)) {
-			keep_waiting = true;
-			continue;
-		}
+		struct gfs2_holder *gh = &ghs[i];
+		int ret2;
 
-		if (test_bit(HIF_HOLDER, &ghs[i].gh_iflags)) {
-			if (ret == -ESTALE)
-				gfs2_glock_dq(&ghs[i]);
-			else
-				gfs2_glock_update_hold_time(ghs[i].gh_gl,
-							    start_time);
+		if (test_bit(HIF_HOLDER, &gh->gh_iflags)) {
+			gfs2_glock_update_hold_time(gh->gh_gl,
+						    start_time);
 		}
+		ret2 = gfs2_glock_holder_ready(gh);
 		if (!ret)
-			ret = ghs[i].gh_error;
+			ret = ret2;
 	}
 
-	if (keep_waiting)
-		goto wait_for_dlm;
+out:
+	if (ret) {
+		for (i = 0; i < num_gh; i++) {
+			struct gfs2_holder *gh = &ghs[i];
 
-	/*
-	 * At this point, we've either acquired all locks or released them all.
-	 */
+			gfs2_glock_dq(gh);
+		}
+	}
 	return ret;
 }
 
@@ -1463,6 +1459,15 @@ void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
 	va_end(args);
 }
 
+static inline bool pid_is_meaningful(const struct gfs2_holder *gh)
+{
+        if (!(gh->gh_flags & GL_NOPID))
+                return true;
+        if (gh->gh_state == LM_ST_UNLOCKED)
+                return true;
+        return false;
+}
+
 /**
  * add_to_queue - Add a holder to the wait queue (but look for recursion)
  * @gh: the holder structure to add
@@ -1489,20 +1494,27 @@ __acquires(&gl->gl_lockref.lock)
 
 	if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
 		if (test_bit(GLF_LOCK, &gl->gl_flags)) {
-			struct gfs2_holder *first_gh;
+			struct gfs2_holder *current_gh;
 
-			first_gh = find_first_strong_holder(gl);
-			try_futile = !may_grant(gl, first_gh, gh);
+			current_gh = find_first_strong_holder(gl);
+			try_futile = !may_grant(gl, current_gh, gh);
 		}
 		if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
 			goto fail;
 	}
 
 	list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
-		if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid &&
-		    (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK) &&
-		    !test_bit(HIF_MAY_DEMOTE, &gh2->gh_iflags)))
-			goto trap_recursive;
+		if (likely(gh2->gh_owner_pid != gh->gh_owner_pid))
+			continue;
+		if (gh->gh_gl->gl_ops->go_type == LM_TYPE_FLOCK)
+			continue;
+		if (test_bit(HIF_MAY_DEMOTE, &gh2->gh_iflags))
+			continue;
+		if (!pid_is_meaningful(gh2))
+			continue;
+		goto trap_recursive;
+	}
+	list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
 		if (try_futile &&
 		    !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
 fail:
@@ -1568,6 +1580,7 @@ int gfs2_glock_nq(struct gfs2_holder *gh)
 	if (test_bit(GLF_LRU, &gl->gl_flags))
 		gfs2_glock_remove_from_lru(gl);
 
+	gh->gh_error = 0;
 	spin_lock(&gl->gl_lockref.lock);
 	add_to_queue(gh);
 	if (unlikely((LM_FLAG_NOEXP & gh->gh_flags) &&
@@ -1694,6 +1707,14 @@ void gfs2_glock_dq(struct gfs2_holder *gh)
 	struct gfs2_glock *gl = gh->gh_gl;
 
 	spin_lock(&gl->gl_lockref.lock);
+	if (list_is_first(&gh->gh_list, &gl->gl_holders) &&
+	    !test_bit(HIF_HOLDER, &gh->gh_iflags)) {
+		spin_unlock(&gl->gl_lockref.lock);
+		gl->gl_name.ln_sbd->sd_lockstruct.ls_ops->lm_cancel(gl);
+		wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE);
+		spin_lock(&gl->gl_lockref.lock);
+	}
+
 	__gfs2_glock_dq(gh);
 	spin_unlock(&gl->gl_lockref.lock);
 }
@@ -1769,7 +1790,7 @@ static int glock_compare(const void *arg_a, const void *arg_b)
 }
 
 /**
- * nq_m_sync - synchonously acquire more than one glock in deadlock free order
+ * nq_m_sync - synchronously acquire more than one glock in deadlock free order
  * @num_gh: the number of structures
  * @ghs: an array of struct gfs2_holder structures
  * @p: placeholder for the holder structure to pass back
@@ -1790,8 +1811,6 @@ static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
 	sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
 
 	for (x = 0; x < num_gh; x++) {
-		p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
-
 		error = gfs2_glock_nq(p[x]);
 		if (error) {
 			while (x--)
@@ -1808,7 +1827,6 @@ static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
  * @num_gh: the number of structures
  * @ghs: an array of struct gfs2_holder structures
  *
- *
  * Returns: 0 on success (all glocks acquired),
  *          errno on failure (no glocks acquired)
  */
@@ -1823,7 +1841,6 @@ int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
 	case 0:
 		return 0;
 	case 1:
-		ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
 		return gfs2_glock_nq(ghs);
 	default:
 		if (num_gh <= 4)
@@ -2216,6 +2233,20 @@ static void dump_glock_func(struct gfs2_glock *gl)
 	dump_glock(NULL, gl, true);
 }
 
+static void withdraw_dq(struct gfs2_glock *gl)
+{
+	spin_lock(&gl->gl_lockref.lock);
+	if (!__lockref_is_dead(&gl->gl_lockref) &&
+	    glock_blocked_by_withdraw(gl))
+		do_error(gl, LM_OUT_ERROR); /* remove pending waiters */
+	spin_unlock(&gl->gl_lockref.lock);
+}
+
+void gfs2_gl_dq_holders(struct gfs2_sbd *sdp)
+{
+	glock_hash_walk(withdraw_dq, sdp);
+}
+
 /**
  * gfs2_gl_hash_clear - Empty out the glock hash table
  * @sdp: the filesystem
@@ -2235,20 +2266,6 @@ void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
 	glock_hash_walk(dump_glock_func, sdp);
 }
 
-void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
-{
-	struct gfs2_glock *gl = ip->i_gl;
-	int ret;
-
-	ret = gfs2_truncatei_resume(ip);
-	gfs2_glock_assert_withdraw(gl, ret == 0);
-
-	spin_lock(&gl->gl_lockref.lock);
-	clear_bit(GLF_LOCK, &gl->gl_flags);
-	run_queue(gl, 1);
-	spin_unlock(&gl->gl_lockref.lock);
-}
-
 static const char *state2str(unsigned state)
 {
 	switch(state) {
@@ -2308,19 +2325,24 @@ static const char *hflags2str(char *buf, u16 flags, unsigned long iflags)
 static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh,
 			const char *fs_id_buf)
 {
-	struct task_struct *gh_owner = NULL;
+	const char *comm = "(none)";
+	pid_t owner_pid = 0;
 	char flags_buf[32];
 
 	rcu_read_lock();
-	if (gh->gh_owner_pid)
+	if (pid_is_meaningful(gh)) {
+		struct task_struct *gh_owner;
+
+		comm = "(ended)";
+		owner_pid = pid_nr(gh->gh_owner_pid);
 		gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
+		if (gh_owner)
+			comm = gh_owner->comm;
+	}
 	gfs2_print_dbg(seq, "%s H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
 		       fs_id_buf, state2str(gh->gh_state),
 		       hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
-		       gh->gh_error,
-		       gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
-		       gh_owner ? gh_owner->comm : "(ended)",
-		       (void *)gh->gh_ip);
+		       gh->gh_error, (long)owner_pid, comm, (void *)gh->gh_ip);
 	rcu_read_unlock();
 }
 
@@ -2523,7 +2545,7 @@ int __init gfs2_glock_init(void)
 		return -ENOMEM;
 	}
 
-	ret = register_shrinker(&glock_shrinker);
+	ret = register_shrinker(&glock_shrinker, "gfs2-glock");
 	if (ret) {
 		destroy_workqueue(gfs2_delete_workqueue);
 		destroy_workqueue(glock_workqueue);
@@ -2735,6 +2757,172 @@ static const struct file_operations gfs2_glstats_fops = {
 	.release = gfs2_glocks_release,
 };
 
+struct gfs2_glockfd_iter {
+	struct super_block *sb;
+	unsigned int tgid;
+	struct task_struct *task;
+	unsigned int fd;
+	struct file *file;
+};
+
+static struct task_struct *gfs2_glockfd_next_task(struct gfs2_glockfd_iter *i)
+{
+	struct pid_namespace *ns = task_active_pid_ns(current);
+	struct pid *pid;
+
+	if (i->task)
+		put_task_struct(i->task);
+
+	rcu_read_lock();
+retry:
+	i->task = NULL;
+	pid = find_ge_pid(i->tgid, ns);
+	if (pid) {
+		i->tgid = pid_nr_ns(pid, ns);
+		i->task = pid_task(pid, PIDTYPE_TGID);
+		if (!i->task) {
+			i->tgid++;
+			goto retry;
+		}
+		get_task_struct(i->task);
+	}
+	rcu_read_unlock();
+	return i->task;
+}
+
+static struct file *gfs2_glockfd_next_file(struct gfs2_glockfd_iter *i)
+{
+	if (i->file) {
+		fput(i->file);
+		i->file = NULL;
+	}
+
+	rcu_read_lock();
+	for(;; i->fd++) {
+		struct inode *inode;
+
+		i->file = task_lookup_next_fd_rcu(i->task, &i->fd);
+		if (!i->file) {
+			i->fd = 0;
+			break;
+		}
+		inode = file_inode(i->file);
+		if (inode->i_sb != i->sb)
+			continue;
+		if (get_file_rcu(i->file))
+			break;
+	}
+	rcu_read_unlock();
+	return i->file;
+}
+
+static void *gfs2_glockfd_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	struct gfs2_glockfd_iter *i = seq->private;
+
+	if (*pos)
+		return NULL;
+	while (gfs2_glockfd_next_task(i)) {
+		if (gfs2_glockfd_next_file(i))
+			return i;
+		i->tgid++;
+	}
+	return NULL;
+}
+
+static void *gfs2_glockfd_seq_next(struct seq_file *seq, void *iter_ptr,
+				   loff_t *pos)
+{
+	struct gfs2_glockfd_iter *i = seq->private;
+
+	(*pos)++;
+	i->fd++;
+	do {
+		if (gfs2_glockfd_next_file(i))
+			return i;
+		i->tgid++;
+	} while (gfs2_glockfd_next_task(i));
+	return NULL;
+}
+
+static void gfs2_glockfd_seq_stop(struct seq_file *seq, void *iter_ptr)
+{
+	struct gfs2_glockfd_iter *i = seq->private;
+
+	if (i->file)
+		fput(i->file);
+	if (i->task)
+		put_task_struct(i->task);
+}
+
+static void gfs2_glockfd_seq_show_flock(struct seq_file *seq,
+					struct gfs2_glockfd_iter *i)
+{
+	struct gfs2_file *fp = i->file->private_data;
+	struct gfs2_holder *fl_gh = &fp->f_fl_gh;
+	struct lm_lockname gl_name = { .ln_type = LM_TYPE_RESERVED };
+
+	if (!READ_ONCE(fl_gh->gh_gl))
+		return;
+
+	spin_lock(&i->file->f_lock);
+	if (gfs2_holder_initialized(fl_gh))
+		gl_name = fl_gh->gh_gl->gl_name;
+	spin_unlock(&i->file->f_lock);
+
+	if (gl_name.ln_type != LM_TYPE_RESERVED) {
+		seq_printf(seq, "%d %u %u/%llx\n",
+			   i->tgid, i->fd, gl_name.ln_type,
+			   (unsigned long long)gl_name.ln_number);
+	}
+}
+
+static int gfs2_glockfd_seq_show(struct seq_file *seq, void *iter_ptr)
+{
+	struct gfs2_glockfd_iter *i = seq->private;
+	struct inode *inode = file_inode(i->file);
+	struct gfs2_glock *gl;
+
+	inode_lock_shared(inode);
+	gl = GFS2_I(inode)->i_iopen_gh.gh_gl;
+	if (gl) {
+		seq_printf(seq, "%d %u %u/%llx\n",
+			   i->tgid, i->fd, gl->gl_name.ln_type,
+			   (unsigned long long)gl->gl_name.ln_number);
+	}
+	gfs2_glockfd_seq_show_flock(seq, i);
+	inode_unlock_shared(inode);
+	return 0;
+}
+
+static const struct seq_operations gfs2_glockfd_seq_ops = {
+	.start = gfs2_glockfd_seq_start,
+	.next  = gfs2_glockfd_seq_next,
+	.stop  = gfs2_glockfd_seq_stop,
+	.show  = gfs2_glockfd_seq_show,
+};
+
+static int gfs2_glockfd_open(struct inode *inode, struct file *file)
+{
+	struct gfs2_glockfd_iter *i;
+	struct gfs2_sbd *sdp = inode->i_private;
+
+	i = __seq_open_private(file, &gfs2_glockfd_seq_ops,
+			       sizeof(struct gfs2_glockfd_iter));
+	if (!i)
+		return -ENOMEM;
+	i->sb = sdp->sd_vfs;
+	return 0;
+}
+
+static const struct file_operations gfs2_glockfd_fops = {
+	.owner   = THIS_MODULE,
+	.open    = gfs2_glockfd_open,
+	.read    = seq_read,
+	.llseek  = seq_lseek,
+	.release = seq_release_private,
+};
+
 DEFINE_SEQ_ATTRIBUTE(gfs2_sbstats);
 
 void gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
@@ -2744,6 +2932,9 @@ void gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
 	debugfs_create_file("glocks", S_IFREG | S_IRUGO, sdp->debugfs_dir, sdp,
 			    &gfs2_glocks_fops);
 
+	debugfs_create_file("glockfd", S_IFREG | S_IRUGO, sdp->debugfs_dir, sdp,
+			    &gfs2_glockfd_fops);
+
 	debugfs_create_file("glstats", S_IFREG | S_IRUGO, sdp->debugfs_dir, sdp,
 			    &gfs2_glstats_fops);