bcache: add return value check to bch_cached_dev_run()

This patch adds return value check to bch_cached_dev_run(), now if there
is error happens inside bch_cached_dev_run(), it can be catched.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/md/bcache/bcache.h

@@ -1006,7 +1006,7 @@ int bch_flash_dev_create(struct cache_set *c, uint64_t size);
 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c,
 			  uint8_t *set_uuid);
 void bch_cached_dev_detach(struct cached_dev *dc);
-void bch_cached_dev_run(struct cached_dev *dc);
+int bch_cached_dev_run(struct cached_dev *dc);
 void bcache_device_stop(struct bcache_device *d);
 
 void bch_cache_set_unregister(struct cache_set *c);

drivers/md/bcache/super.c

@@ -910,7 +910,7 @@ static int cached_dev_status_update(void *arg)
 }
 
 
-void bch_cached_dev_run(struct cached_dev *dc)
+int bch_cached_dev_run(struct cached_dev *dc)
 {
 	struct bcache_device *d = &dc->disk;
 	char *buf = kmemdup_nul(dc->sb.label, SB_LABEL_SIZE, GFP_KERNEL);
@@ -921,11 +921,14 @@ void bch_cached_dev_run(struct cached_dev *dc)
 		NULL,
 	};
 
+	if (dc->io_disable)
+		return -EIO;
+
 	if (atomic_xchg(&dc->running, 1)) {
 		kfree(env[1]);
 		kfree(env[2]);
 		kfree(buf);
-		return;
+		return -EBUSY;
 	}
 
 	if (!d->c &&
@@ -951,8 +954,11 @@ void bch_cached_dev_run(struct cached_dev *dc)
 	kfree(buf);
 
 	if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
-	    sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache"))
+	    sysfs_create_link(&disk_to_dev(d->disk)->kobj,
+			      &d->kobj, "bcache")) {
 		pr_debug("error creating sysfs link");
+		return -ENOMEM;
+	}
 
 	dc->status_update_thread = kthread_run(cached_dev_status_update,
 					       dc, "bcache_status_update");
@@ -961,6 +967,8 @@ void bch_cached_dev_run(struct cached_dev *dc)
 			"continue to run without monitoring backing "
 			"device status");
 	}
+
+	return 0;
 }
 
 /*
@@ -1056,6 +1064,7 @@ int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c,
 	uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds());
 	struct uuid_entry *u;
 	struct cached_dev *exist_dc, *t;
+	int ret = 0;
 
 	if ((set_uuid && memcmp(set_uuid, c->sb.set_uuid, 16)) ||
 	    (!set_uuid && memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16)))
@@ -1165,7 +1174,12 @@ int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c,
 
 	bch_sectors_dirty_init(&dc->disk);
 
-	bch_cached_dev_run(dc);
+	ret = bch_cached_dev_run(dc);
+	if (ret && (ret != -EBUSY)) {
+		up_write(&dc->writeback_lock);
+		return ret;
+	}
+
 	bcache_device_link(&dc->disk, c, "bdev");
 	atomic_inc(&c->attached_dev_nr);
 
@@ -1292,6 +1306,7 @@ static int register_bdev(struct cache_sb *sb, struct page *sb_page,
 {
 	const char *err = "cannot allocate memory";
 	struct cache_set *c;
+	int ret = -ENOMEM;
 
 	bdevname(bdev, dc->backing_dev_name);
 	memcpy(&dc->sb, sb, sizeof(struct cache_sb));
@@ -1321,14 +1336,18 @@ static int register_bdev(struct cache_sb *sb, struct page *sb_page,
 		bch_cached_dev_attach(dc, c, NULL);
 
 	if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE ||
-	    BDEV_STATE(&dc->sb) == BDEV_STATE_STALE)
+	    BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) {
-		bch_cached_dev_run(dc);
+		err = "failed to run cached device";
+		ret = bch_cached_dev_run(dc);
+		if (ret)
+			goto err;
+	}
 
 	return 0;
 err:
 	pr_notice("error %s: %s", dc->backing_dev_name, err);
 	bcache_device_stop(&dc->disk);
-	return -EIO;
+	return ret;
 }
 
 /* Flash only volumes */

drivers/md/bcache/sysfs.c

@@ -325,8 +325,11 @@ STORE(__cached_dev)
 		bch_cache_accounting_clear(&dc->accounting);
 
 	if (attr == &sysfs_running &&
-	    strtoul_or_return(buf))
+	    strtoul_or_return(buf)) {
-		bch_cached_dev_run(dc);
+		v = bch_cached_dev_run(dc);
+		if (v)
+			return v;
+	}
 
 	if (attr == &sysfs_cache_mode) {
 		v = sysfs_match_string(bch_cache_modes, buf);