1 files changed, 165 insertions, 11 deletions

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 64541d8bf9ad..2299dcc417ea 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -125,12 +125,11 @@ static void gfs2_glock_dealloc(struct rcu_head *rcu)
 {
 	struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
 
-	if (gl->gl_ops->go_flags & GLOF_ASPACE) {
+	kfree(gl->gl_lksb.sb_lvbptr);
+	if (gl->gl_ops->go_flags & GLOF_ASPACE)
 		kmem_cache_free(gfs2_glock_aspace_cachep, gl);
-	} else {
-		kfree(gl->gl_lksb.sb_lvbptr);
+	else
 		kmem_cache_free(gfs2_glock_cachep, gl);
-	}
 }
 
 /**
@@ -465,6 +464,15 @@ static void state_change(struct gfs2_glock *gl, unsigned int new_state)
 	gl->gl_tchange = jiffies;
 }
 
+static void gfs2_set_demote(struct gfs2_glock *gl)
+{
+	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
+
+	set_bit(GLF_DEMOTE, &gl->gl_flags);
+	smp_mb();
+	wake_up(&sdp->sd_async_glock_wait);
+}
+
 static void gfs2_demote_wake(struct gfs2_glock *gl)
 {
 	gl->gl_demote_state = LM_ST_EXCLUSIVE;
@@ -757,20 +765,127 @@ out_unlock:
 	return;
 }
 
+void gfs2_inode_remember_delete(struct gfs2_glock *gl, u64 generation)
+{
+	struct gfs2_inode_lvb *ri = (void *)gl->gl_lksb.sb_lvbptr;
+
+	if (ri->ri_magic == 0)
+		ri->ri_magic = cpu_to_be32(GFS2_MAGIC);
+	if (ri->ri_magic == cpu_to_be32(GFS2_MAGIC))
+		ri->ri_generation_deleted = cpu_to_be64(generation);
+}
+
+bool gfs2_inode_already_deleted(struct gfs2_glock *gl, u64 generation)
+{
+	struct gfs2_inode_lvb *ri = (void *)gl->gl_lksb.sb_lvbptr;
+
+	if (ri->ri_magic != cpu_to_be32(GFS2_MAGIC))
+		return false;
+	return generation <= be64_to_cpu(ri->ri_generation_deleted);
+}
+
+static void gfs2_glock_poke(struct gfs2_glock *gl)
+{
+	int flags = LM_FLAG_TRY_1CB | LM_FLAG_ANY | GL_SKIP;
+	struct gfs2_holder gh;
+	int error;
+
+	error = gfs2_glock_nq_init(gl, LM_ST_SHARED, flags, &gh);
+	if (!error)
+		gfs2_glock_dq(&gh);
+}
+
+static bool gfs2_try_evict(struct gfs2_glock *gl)
+{
+	struct gfs2_inode *ip;
+	bool evicted = false;
+
+	/*
+	 * If there is contention on the iopen glock and we have an inode, try
+	 * to grab and release the inode so that it can be evicted.  This will
+	 * allow the remote node to go ahead and delete the inode without us
+	 * having to do it, which will avoid rgrp glock thrashing.
+	 *
+	 * The remote node is likely still holding the corresponding inode
+	 * glock, so it will run before we get to verify that the delete has
+	 * happened below.
+	 */
+	spin_lock(&gl->gl_lockref.lock);
+	ip = gl->gl_object;
+	if (ip && !igrab(&ip->i_inode))
+		ip = NULL;
+	spin_unlock(&gl->gl_lockref.lock);
+	if (ip) {
+		struct gfs2_glock *inode_gl = NULL;
+
+		gl->gl_no_formal_ino = ip->i_no_formal_ino;
+		set_bit(GIF_DEFERRED_DELETE, &ip->i_flags);
+		d_prune_aliases(&ip->i_inode);
+		iput(&ip->i_inode);
+
+		/* If the inode was evicted, gl->gl_object will now be NULL. */
+		spin_lock(&gl->gl_lockref.lock);
+		ip = gl->gl_object;
+		if (ip) {
+			inode_gl = ip->i_gl;
+			lockref_get(&inode_gl->gl_lockref);
+			clear_bit(GIF_DEFERRED_DELETE, &ip->i_flags);
+		}
+		spin_unlock(&gl->gl_lockref.lock);
+		if (inode_gl) {
+			gfs2_glock_poke(inode_gl);
+			gfs2_glock_put(inode_gl);
+		}
+		evicted = !ip;
+	}
+	return evicted;
+}
+
 static void delete_work_func(struct work_struct *work)
 {
-	struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
+	struct delayed_work *dwork = to_delayed_work(work);
+	struct gfs2_glock *gl = container_of(dwork, struct gfs2_glock, gl_delete);
 	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 	struct inode *inode;
 	u64 no_addr = gl->gl_name.ln_number;
 
+	spin_lock(&gl->gl_lockref.lock);
+	clear_bit(GLF_PENDING_DELETE, &gl->gl_flags);
+	spin_unlock(&gl->gl_lockref.lock);
+
 	/* If someone's using this glock to create a new dinode, the block must
 	   have been freed by another node, then re-used, in which case our
 	   iopen callback is too late after the fact. Ignore it. */
 	if (test_bit(GLF_INODE_CREATING, &gl->gl_flags))
 		goto out;
 
-	inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
+	if (test_bit(GLF_DEMOTE, &gl->gl_flags)) {
+		/*
+		 * If we can evict the inode, give the remote node trying to
+		 * delete the inode some time before verifying that the delete
+		 * has happened.  Otherwise, if we cause contention on the inode glock
+		 * immediately, the remote node will think that we still have
+		 * the inode in use, and so it will give up waiting.
+		 *
+		 * If we can't evict the inode, signal to the remote node that
+		 * the inode is still in use.  We'll later try to delete the
+		 * inode locally in gfs2_evict_inode.
+		 *
+		 * FIXME: We only need to verify that the remote node has
+		 * deleted the inode because nodes before this remote delete
+		 * rework won't cooperate.  At a later time, when we no longer
+		 * care about compatibility with such nodes, we can skip this
+		 * step entirely.
+		 */
+		if (gfs2_try_evict(gl)) {
+			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)) {
 		d_prune_aliases(inode);
 		iput(inode);
@@ -801,7 +916,7 @@ static void glock_work_func(struct work_struct *work)
 
 		if (!delay) {
 			clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
-			set_bit(GLF_DEMOTE, &gl->gl_flags);
+			gfs2_set_demote(gl);
 		}
 	}
 	run_queue(gl, 0);
@@ -932,7 +1047,7 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
 	gl->gl_object = NULL;
 	gl->gl_hold_time = GL_GLOCK_DFT_HOLD;
 	INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
-	INIT_WORK(&gl->gl_delete, delete_work_func);
+	INIT_DELAYED_WORK(&gl->gl_delete, delete_work_func);
 
 	mapping = gfs2_glock2aspace(gl);
 	if (mapping) {
@@ -1146,9 +1261,10 @@ wait_for_dlm:
 static void handle_callback(struct gfs2_glock *gl, unsigned int state,
 			    unsigned long delay, bool remote)
 {
-	int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
-
-	set_bit(bit, &gl->gl_flags);
+	if (delay)
+		set_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
+	else
+		gfs2_set_demote(gl);
 	if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
 		gl->gl_demote_state = state;
 		gl->gl_demote_time = jiffies;
@@ -1755,6 +1871,44 @@ static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
 	rhashtable_walk_exit(&iter);
 }
 
+bool gfs2_queue_delete_work(struct gfs2_glock *gl, unsigned long delay)
+{
+	bool queued;
+
+	spin_lock(&gl->gl_lockref.lock);
+	queued = queue_delayed_work(gfs2_delete_workqueue,
+				    &gl->gl_delete, delay);
+	if (queued)
+		set_bit(GLF_PENDING_DELETE, &gl->gl_flags);
+	spin_unlock(&gl->gl_lockref.lock);
+	return queued;
+}
+
+void gfs2_cancel_delete_work(struct gfs2_glock *gl)
+{
+	if (cancel_delayed_work_sync(&gl->gl_delete)) {
+		clear_bit(GLF_PENDING_DELETE, &gl->gl_flags);
+		gfs2_glock_put(gl);
+	}
+}
+
+bool gfs2_delete_work_queued(const struct gfs2_glock *gl)
+{
+	return test_bit(GLF_PENDING_DELETE, &gl->gl_flags);
+}
+
+static void flush_delete_work(struct gfs2_glock *gl)
+{
+	flush_delayed_work(&gl->gl_delete);
+	gfs2_glock_queue_work(gl, 0);
+}
+
+void gfs2_flush_delete_work(struct gfs2_sbd *sdp)
+{
+	glock_hash_walk(flush_delete_work, sdp);
+	flush_workqueue(gfs2_delete_workqueue);
+}
+
 /**
  * thaw_glock - thaw out a glock which has an unprocessed reply waiting
  * @gl: The glock to thaw