gfs2: Move delete workqueue into super block

Move the global delete workqueue into struct gfs2_sbd so that we can
flush / drain it without interfering with other filesystems.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

fs/gfs2/glock.c

@@ -67,7 +67,6 @@ static void handle_callback(struct gfs2_glock *gl, unsigned int state,
 
 static struct dentry *gfs2_root;
 static struct workqueue_struct *glock_workqueue;
-struct workqueue_struct *gfs2_delete_workqueue;
 static LIST_HEAD(lru_list);
 static atomic_t lru_count = ATOMIC_INIT(0);
 static DEFINE_SPINLOCK(lru_lock);
@@ -2060,7 +2059,9 @@ static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
 
 bool gfs2_queue_delete_work(struct gfs2_glock *gl, unsigned long delay)
 {
-	return queue_delayed_work(gfs2_delete_workqueue,
+	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
+
+	return queue_delayed_work(sdp->sd_delete_wq,
 				  &gl->gl_delete, delay);
 }
 
@@ -2073,8 +2074,10 @@ void gfs2_cancel_delete_work(struct gfs2_glock *gl)
 static void flush_delete_work(struct gfs2_glock *gl)
 {
 	if (gl->gl_name.ln_type == LM_TYPE_IOPEN) {
+		struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
+
 		if (cancel_delayed_work(&gl->gl_delete)) {
-			queue_delayed_work(gfs2_delete_workqueue,
+			queue_delayed_work(sdp->sd_delete_wq,
 					   &gl->gl_delete, 0);
 		}
 	}
@@ -2083,7 +2086,7 @@ static void flush_delete_work(struct gfs2_glock *gl)
 void gfs2_flush_delete_work(struct gfs2_sbd *sdp)
 {
 	glock_hash_walk(flush_delete_work, sdp);
-	flush_workqueue(gfs2_delete_workqueue);
+	flush_workqueue(sdp->sd_delete_wq);
 }
 
 /**
@@ -2444,18 +2447,9 @@ int __init gfs2_glock_init(void)
 		rhashtable_destroy(&gl_hash_table);
 		return -ENOMEM;
 	}
-	gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
-						WQ_MEM_RECLAIM | WQ_FREEZABLE,
-						0);
-	if (!gfs2_delete_workqueue) {
-		destroy_workqueue(glock_workqueue);
-		rhashtable_destroy(&gl_hash_table);
-		return -ENOMEM;
-	}
 
 	ret = register_shrinker(&glock_shrinker, "gfs2-glock");
 	if (ret) {
-		destroy_workqueue(gfs2_delete_workqueue);
 		destroy_workqueue(glock_workqueue);
 		rhashtable_destroy(&gl_hash_table);
 		return ret;
@@ -2472,7 +2466,6 @@ void gfs2_glock_exit(void)
 	unregister_shrinker(&glock_shrinker);
 	rhashtable_destroy(&gl_hash_table);
 	destroy_workqueue(glock_workqueue);
-	destroy_workqueue(gfs2_delete_workqueue);
 }
 
 static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi, loff_t n)

fs/gfs2/glock.h

@@ -144,7 +144,6 @@ struct gfs2_glock_aspace {
 	struct address_space mapping;
 };
 
-extern struct workqueue_struct *gfs2_delete_workqueue;
 static inline struct gfs2_holder *gfs2_glock_is_locked_by_me(struct gfs2_glock *gl)
 {
 	struct gfs2_holder *gh;

fs/gfs2/incore.h

@@ -770,6 +770,10 @@ struct gfs2_sbd {
 
 	struct completion sd_journal_ready;
 
+	/* Workqueue stuff */
+
+	struct workqueue_struct *sd_delete_wq;
+
 	/* Daemon stuff */
 
 	struct task_struct *sd_logd_process;

fs/gfs2/ops_fstype.c

@@ -1197,9 +1197,15 @@ static int gfs2_fill_super(struct super_block *sb, struct fs_context *fc)
 
 	snprintf(sdp->sd_fsname, sizeof(sdp->sd_fsname), "%s", sdp->sd_table_name);
 
+	sdp->sd_delete_wq = alloc_workqueue("gfs2-delete/%s",
+			WQ_MEM_RECLAIM | WQ_FREEZABLE, 0, sdp->sd_fsname);
+	error = -ENOMEM;
+	if (!sdp->sd_delete_wq)
+		goto fail_free;
+
 	error = gfs2_sys_fs_add(sdp);
 	if (error)
-		goto fail_free;
+		goto fail_delete_wq;
 
 	gfs2_create_debugfs_file(sdp);
 
@@ -1309,6 +1315,8 @@ static int gfs2_fill_super(struct super_block *sb, struct fs_context *fc)
 fail_debug:
 	gfs2_delete_debugfs_file(sdp);
 	gfs2_sys_fs_del(sdp);
+fail_delete_wq:
+	destroy_workqueue(sdp->sd_delete_wq);
 fail_free:
 	free_sbd(sdp);
 	sb->s_fs_info = NULL;

fs/gfs2/super.c

@@ -630,6 +630,8 @@ static void gfs2_put_super(struct super_block *sb)
 	/*  Unmount the locking protocol  */
 	gfs2_lm_unmount(sdp);
 
+	destroy_workqueue(sdp->sd_delete_wq);
+
 	/*  At this point, we're through participating in the lockspace  */
 	gfs2_sys_fs_del(sdp);
 	free_sbd(sdp);