Merge tag 'for-linus-20190125' of git://git.kernel.dk/linux-block

Pull block fixes from Jens Axboe:
 "A collection of fixes for this release. This contains:

   - Silence sparse rightfully complaining about non-static wbt
     functions (Bart)

   - Fixes for the zoned comments/ioctl documentation (Damien)

   - direct-io fix that's been lingering for a while (Ernesto)

   - cgroup writeback fix (Tejun)

   - Set of NVMe patches for nvme-rdma/tcp (Sagi, Hannes, Raju)

   - Block recursion tracking fix (Ming)

   - Fix debugfs command flag naming for a few flags (Jianchao)"

* tag 'for-linus-20190125' of git://git.kernel.dk/linux-block:
  block: Fix comment typo
  uapi: fix ioctl documentation
  blk-wbt: Declare local functions static
  blk-mq: fix the cmd_flag_name array
  nvme-multipath: drop optimization for static ANA group IDs
  nvmet-rdma: fix null dereference under heavy load
  nvme-rdma: rework queue maps handling
  nvme-tcp: fix timeout handler
  nvme-rdma: fix timeout handler
  writeback: synchronize sync(2) against cgroup writeback membership switches
  block: cover another queue enter recursion via BIO_QUEUE_ENTERED
  direct-io: allow direct writes to empty inodes

14 files changed, 129 insertions, 50 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 3c5f61ceeb67..1ccec27d20c3 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1083,7 +1083,18 @@ blk_qc_t generic_make_request(struct bio *bio)
 			/* Create a fresh bio_list for all subordinate requests */
 			bio_list_on_stack[1] = bio_list_on_stack[0];
 			bio_list_init(&bio_list_on_stack[0]);
+
+			/*
+			 * Since we're recursing into make_request here, ensure
+			 * that we mark this bio as already having entered the queue.
+			 * If not, and the queue is going away, we can get stuck
+			 * forever on waiting for the queue reference to drop. But
+			 * that will never happen, as we're already holding a
+			 * reference to it.
+			 */
+			bio_set_flag(bio, BIO_QUEUE_ENTERED);
 			ret = q->make_request_fn(q, bio);
+			bio_clear_flag(bio, BIO_QUEUE_ENTERED);
 
 			/* sort new bios into those for a lower level
 			 * and those for the same level
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 71e9ac03f621..d79a22f111d1 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -272,16 +272,6 @@ void blk_queue_split(struct request_queue *q, struct bio **bio)
 		/* there isn't chance to merge the splitted bio */
 		split->bi_opf |= REQ_NOMERGE;
 
-		/*
-		 * Since we're recursing into make_request here, ensure
-		 * that we mark this bio as already having entered the queue.
-		 * If not, and the queue is going away, we can get stuck
-		 * forever on waiting for the queue reference to drop. But
-		 * that will never happen, as we're already holding a
-		 * reference to it.
-		 */
-		bio_set_flag(*bio, BIO_QUEUE_ENTERED);
-
 		bio_chain(split, *bio);
 		trace_block_split(q, split, (*bio)->bi_iter.bi_sector);
 		generic_make_request(*bio);
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 90d68760af08..f8120832ca7b 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -308,8 +308,9 @@ static const char *const cmd_flag_name[] = {
 	CMD_FLAG_NAME(PREFLUSH),
 	CMD_FLAG_NAME(RAHEAD),
 	CMD_FLAG_NAME(BACKGROUND),
-	CMD_FLAG_NAME(NOUNMAP),
 	CMD_FLAG_NAME(NOWAIT),
+	CMD_FLAG_NAME(NOUNMAP),
+	CMD_FLAG_NAME(HIPRI),
 };
 #undef CMD_FLAG_NAME
 
diff --git a/block/blk-wbt.c b/block/blk-wbt.c
index f0c56649775f..fd166fbb0f65 100644
--- a/block/blk-wbt.c
+++ b/block/blk-wbt.c
@@ -597,7 +597,7 @@ static void wbt_track(struct rq_qos *rqos, struct request *rq, struct bio *bio)
 	rq->wbt_flags |= bio_to_wbt_flags(rwb, bio);
 }
 
-void wbt_issue(struct rq_qos *rqos, struct request *rq)
+static void wbt_issue(struct rq_qos *rqos, struct request *rq)
 {
 	struct rq_wb *rwb = RQWB(rqos);
 
@@ -617,7 +617,7 @@ void wbt_issue(struct rq_qos *rqos, struct request *rq)
 	}
 }
 
-void wbt_requeue(struct rq_qos *rqos, struct request *rq)
+static void wbt_requeue(struct rq_qos *rqos, struct request *rq)
 {
 	struct rq_wb *rwb = RQWB(rqos);
 	if (!rwb_enabled(rwb))
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index df4b3a6db51b..b9fff3b8ed1b 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -545,8 +545,7 @@ int nvme_mpath_init(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 	timer_setup(&ctrl->anatt_timer, nvme_anatt_timeout, 0);
 	ctrl->ana_log_size = sizeof(struct nvme_ana_rsp_hdr) +
 		ctrl->nanagrpid * sizeof(struct nvme_ana_group_desc);
-	if (!(ctrl->anacap & (1 << 6)))
-		ctrl->ana_log_size += ctrl->max_namespaces * sizeof(__le32);
+	ctrl->ana_log_size += ctrl->max_namespaces * sizeof(__le32);
 
 	if (ctrl->ana_log_size > ctrl->max_hw_sectors << SECTOR_SHIFT) {
 		dev_err(ctrl->device,
diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index 0a2fd2949ad7..52abc3a6de12 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -119,6 +119,7 @@ struct nvme_rdma_ctrl {
 
 	struct nvme_ctrl	ctrl;
 	bool			use_inline_data;
+	u32			io_queues[HCTX_MAX_TYPES];
 };
 
 static inline struct nvme_rdma_ctrl *to_rdma_ctrl(struct nvme_ctrl *ctrl)
@@ -165,8 +166,8 @@ static inline int nvme_rdma_queue_idx(struct nvme_rdma_queue *queue)
 static bool nvme_rdma_poll_queue(struct nvme_rdma_queue *queue)
 {
 	return nvme_rdma_queue_idx(queue) >
-		queue->ctrl->ctrl.opts->nr_io_queues +
-		queue->ctrl->ctrl.opts->nr_write_queues;
+		queue->ctrl->io_queues[HCTX_TYPE_DEFAULT] +
+		queue->ctrl->io_queues[HCTX_TYPE_READ];
 }
 
 static inline size_t nvme_rdma_inline_data_size(struct nvme_rdma_queue *queue)
@@ -661,8 +662,21 @@ static int nvme_rdma_alloc_io_queues(struct nvme_rdma_ctrl *ctrl)
 	nr_io_queues = min_t(unsigned int, nr_io_queues,
 				ibdev->num_comp_vectors);
 
-	nr_io_queues += min(opts->nr_write_queues, num_online_cpus());
-	nr_io_queues += min(opts->nr_poll_queues, num_online_cpus());
+	if (opts->nr_write_queues) {
+		ctrl->io_queues[HCTX_TYPE_DEFAULT] =
+				min(opts->nr_write_queues, nr_io_queues);
+		nr_io_queues += ctrl->io_queues[HCTX_TYPE_DEFAULT];
+	} else {
+		ctrl->io_queues[HCTX_TYPE_DEFAULT] = nr_io_queues;
+	}
+
+	ctrl->io_queues[HCTX_TYPE_READ] = nr_io_queues;
+
+	if (opts->nr_poll_queues) {
+		ctrl->io_queues[HCTX_TYPE_POLL] =
+			min(opts->nr_poll_queues, num_online_cpus());
+		nr_io_queues += ctrl->io_queues[HCTX_TYPE_POLL];
+	}
 
 	ret = nvme_set_queue_count(&ctrl->ctrl, &nr_io_queues);
 	if (ret)
@@ -1689,18 +1703,28 @@ static enum blk_eh_timer_return
 nvme_rdma_timeout(struct request *rq, bool reserved)
 {
 	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
+	struct nvme_rdma_queue *queue = req->queue;
+	struct nvme_rdma_ctrl *ctrl = queue->ctrl;
 
-	dev_warn(req->queue->ctrl->ctrl.device,
-		 "I/O %d QID %d timeout, reset controller\n",
-		 rq->tag, nvme_rdma_queue_idx(req->queue));
+	dev_warn(ctrl->ctrl.device, "I/O %d QID %d timeout\n",
+		 rq->tag, nvme_rdma_queue_idx(queue));
 
-	/* queue error recovery */
-	nvme_rdma_error_recovery(req->queue->ctrl);
+	if (ctrl->ctrl.state != NVME_CTRL_LIVE) {
+		/*
+		 * Teardown immediately if controller times out while starting
+		 * or we are already started error recovery. all outstanding
+		 * requests are completed on shutdown, so we return BLK_EH_DONE.
+		 */
+		flush_work(&ctrl->err_work);
+		nvme_rdma_teardown_io_queues(ctrl, false);
+		nvme_rdma_teardown_admin_queue(ctrl, false);
+		return BLK_EH_DONE;
+	}
 
-	/* fail with DNR on cmd timeout */
-	nvme_req(rq)->status = NVME_SC_ABORT_REQ | NVME_SC_DNR;
+	dev_warn(ctrl->ctrl.device, "starting error recovery\n");
+	nvme_rdma_error_recovery(ctrl);
 
-	return BLK_EH_DONE;
+	return BLK_EH_RESET_TIMER;
 }
 
 static blk_status_t nvme_rdma_queue_rq(struct blk_mq_hw_ctx *hctx,
@@ -1779,17 +1803,15 @@ static int nvme_rdma_map_queues(struct blk_mq_tag_set *set)
 	struct nvme_rdma_ctrl *ctrl = set->driver_data;
 
 	set->map[HCTX_TYPE_DEFAULT].queue_offset = 0;
-	set->map[HCTX_TYPE_READ].nr_queues = ctrl->ctrl.opts->nr_io_queues;
+	set->map[HCTX_TYPE_DEFAULT].nr_queues =
+			ctrl->io_queues[HCTX_TYPE_DEFAULT];
+	set->map[HCTX_TYPE_READ].nr_queues = ctrl->io_queues[HCTX_TYPE_READ];
 	if (ctrl->ctrl.opts->nr_write_queues) {
 		/* separate read/write queues */
-		set->map[HCTX_TYPE_DEFAULT].nr_queues =
-				ctrl->ctrl.opts->nr_write_queues;
 		set->map[HCTX_TYPE_READ].queue_offset =
-				ctrl->ctrl.opts->nr_write_queues;
+				ctrl->io_queues[HCTX_TYPE_DEFAULT];
 	} else {
 		/* mixed read/write queues */
-		set->map[HCTX_TYPE_DEFAULT].nr_queues =
-				ctrl->ctrl.opts->nr_io_queues;
 		set->map[HCTX_TYPE_READ].queue_offset = 0;
 	}
 	blk_mq_rdma_map_queues(&set->map[HCTX_TYPE_DEFAULT],
@@ -1799,12 +1821,12 @@ static int nvme_rdma_map_queues(struct blk_mq_tag_set *set)
 
 	if (ctrl->ctrl.opts->nr_poll_queues) {
 		set->map[HCTX_TYPE_POLL].nr_queues =
-				ctrl->ctrl.opts->nr_poll_queues;
+				ctrl->io_queues[HCTX_TYPE_POLL];
 		set->map[HCTX_TYPE_POLL].queue_offset =
-				ctrl->ctrl.opts->nr_io_queues;
+				ctrl->io_queues[HCTX_TYPE_DEFAULT];
 		if (ctrl->ctrl.opts->nr_write_queues)
 			set->map[HCTX_TYPE_POLL].queue_offset +=
-				ctrl->ctrl.opts->nr_write_queues;
+				ctrl->io_queues[HCTX_TYPE_READ];
 		blk_mq_map_queues(&set->map[HCTX_TYPE_POLL]);
 	}
 	return 0;
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 265a0543b381..5f0a00425242 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -1948,20 +1948,23 @@ nvme_tcp_timeout(struct request *rq, bool reserved)
 	struct nvme_tcp_ctrl *ctrl = req->queue->ctrl;
 	struct nvme_tcp_cmd_pdu *pdu = req->pdu;
 
-	dev_dbg(ctrl->ctrl.device,
+	dev_warn(ctrl->ctrl.device,
 		"queue %d: timeout request %#x type %d\n",
-		nvme_tcp_queue_id(req->queue), rq->tag,
-		pdu->hdr.type);
+		nvme_tcp_queue_id(req->queue), rq->tag, pdu->hdr.type);
 
 	if (ctrl->ctrl.state != NVME_CTRL_LIVE) {
-		union nvme_result res = {};
-
-		nvme_req(rq)->flags |= NVME_REQ_CANCELLED;
-		nvme_end_request(rq, cpu_to_le16(NVME_SC_ABORT_REQ), res);
+		/*
+		 * Teardown immediately if controller times out while starting
+		 * or we are already started error recovery. all outstanding
+		 * requests are completed on shutdown, so we return BLK_EH_DONE.
+		 */
+		flush_work(&ctrl->err_work);
+		nvme_tcp_teardown_io_queues(&ctrl->ctrl, false);
+		nvme_tcp_teardown_admin_queue(&ctrl->ctrl, false);
 		return BLK_EH_DONE;
 	}
 
-	/* queue error recovery */
+	dev_warn(ctrl->ctrl.device, "starting error recovery\n");
 	nvme_tcp_error_recovery(&ctrl->ctrl);
 
 	return BLK_EH_RESET_TIMER;
diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
index a8d23eb80192..a884e3a0e8af 100644
--- a/drivers/nvme/target/rdma.c
+++ b/drivers/nvme/target/rdma.c
@@ -139,6 +139,10 @@ static void nvmet_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc);
 static void nvmet_rdma_read_data_done(struct ib_cq *cq, struct ib_wc *wc);
 static void nvmet_rdma_qp_event(struct ib_event *event, void *priv);
 static void nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue);
+static void nvmet_rdma_free_rsp(struct nvmet_rdma_device *ndev,
+				struct nvmet_rdma_rsp *r);
+static int nvmet_rdma_alloc_rsp(struct nvmet_rdma_device *ndev,
+				struct nvmet_rdma_rsp *r);
 
 static const struct nvmet_fabrics_ops nvmet_rdma_ops;
 
@@ -182,9 +186,17 @@ nvmet_rdma_get_rsp(struct nvmet_rdma_queue *queue)
 	spin_unlock_irqrestore(&queue->rsps_lock, flags);
 
 	if (unlikely(!rsp)) {
-		rsp = kmalloc(sizeof(*rsp), GFP_KERNEL);
+		int ret;
+
+		rsp = kzalloc(sizeof(*rsp), GFP_KERNEL);
 		if (unlikely(!rsp))
 			return NULL;
+		ret = nvmet_rdma_alloc_rsp(queue->dev, rsp);
+		if (unlikely(ret)) {
+			kfree(rsp);
+			return NULL;
+		}
+
 		rsp->allocated = true;
 	}
 
@@ -197,6 +209,7 @@ nvmet_rdma_put_rsp(struct nvmet_rdma_rsp *rsp)
 	unsigned long flags;
 
 	if (unlikely(rsp->allocated)) {
+		nvmet_rdma_free_rsp(rsp->queue->dev, rsp);
 		kfree(rsp);
 		return;
 	}
diff --git a/fs/direct-io.c b/fs/direct-io.c
index dbc1a1f080ce..ec2fb6fe6d37 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -679,6 +679,7 @@ static int get_more_blocks(struct dio *dio, struct dio_submit *sdio,
 	unsigned long fs_count;	/* Number of filesystem-sized blocks */
 	int create;
 	unsigned int i_blkbits = sdio->blkbits + sdio->blkfactor;
+	loff_t i_size;
 
 	/*
 	 * If there was a memory error and we've overwritten all the
@@ -708,8 +709,8 @@ static int get_more_blocks(struct dio *dio, struct dio_submit *sdio,
 		 */
 		create = dio->op == REQ_OP_WRITE;
 		if (dio->flags & DIO_SKIP_HOLES) {
-			if (fs_startblk <= ((i_size_read(dio->inode) - 1) >>
-							i_blkbits))
+			i_size = i_size_read(dio->inode);
+			if (i_size && fs_startblk <= (i_size - 1) >> i_blkbits)
 				create = 0;
 		}
 
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index b40168fcc94a..36855c1f8daf 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -331,11 +331,22 @@ struct inode_switch_wbs_context {
 	struct work_struct	work;
 };
 
+static void bdi_down_write_wb_switch_rwsem(struct backing_dev_info *bdi)
+{
+	down_write(&bdi->wb_switch_rwsem);
+}
+
+static void bdi_up_write_wb_switch_rwsem(struct backing_dev_info *bdi)
+{
+	up_write(&bdi->wb_switch_rwsem);
+}
+
 static void inode_switch_wbs_work_fn(struct work_struct *work)
 {
 	struct inode_switch_wbs_context *isw =
 		container_of(work, struct inode_switch_wbs_context, work);
 	struct inode *inode = isw->inode;
+	struct backing_dev_info *bdi = inode_to_bdi(inode);
 	struct address_space *mapping = inode->i_mapping;
 	struct bdi_writeback *old_wb = inode->i_wb;
 	struct bdi_writeback *new_wb = isw->new_wb;
@@ -344,6 +355,12 @@ static void inode_switch_wbs_work_fn(struct work_struct *work)
 	bool switched = false;
 
 	/*
+	 * If @inode switches cgwb membership while sync_inodes_sb() is
+	 * being issued, sync_inodes_sb() might miss it.  Synchronize.
+	 */
+	down_read(&bdi->wb_switch_rwsem);
+
+	/*
 	 * By the time control reaches here, RCU grace period has passed
 	 * since I_WB_SWITCH assertion and all wb stat update transactions
 	 * between unlocked_inode_to_wb_begin/end() are guaranteed to be
@@ -428,6 +445,8 @@ skip_switch:
 	spin_unlock(&new_wb->list_lock);
 	spin_unlock(&old_wb->list_lock);
 
+	up_read(&bdi->wb_switch_rwsem);
+
 	if (switched) {
 		wb_wakeup(new_wb);
 		wb_put(old_wb);
@@ -468,9 +487,18 @@ static void inode_switch_wbs(struct inode *inode, int new_wb_id)
 	if (inode->i_state & I_WB_SWITCH)
 		return;
 
+	/*
+	 * Avoid starting new switches while sync_inodes_sb() is in
+	 * progress.  Otherwise, if the down_write protected issue path
+	 * blocks heavily, we might end up starting a large number of
+	 * switches which will block on the rwsem.
+	 */
+	if (!down_read_trylock(&bdi->wb_switch_rwsem))
+		return;
+
 	isw = kzalloc(sizeof(*isw), GFP_ATOMIC);
 	if (!isw)
-		return;
+		goto out_unlock;
 
 	/* find and pin the new wb */
 	rcu_read_lock();
@@ -504,12 +532,14 @@ static void inode_switch_wbs(struct inode *inode, int new_wb_id)
 	 * Let's continue after I_WB_SWITCH is guaranteed to be visible.
 	 */
 	call_rcu(&isw->rcu_head, inode_switch_wbs_rcu_fn);
-	return;
+	goto out_unlock;
 
 out_free:
 	if (isw->new_wb)
 		wb_put(isw->new_wb);
 	kfree(isw);
+out_unlock:
+	up_read(&bdi->wb_switch_rwsem);
 }
 
 /**
@@ -887,6 +917,9 @@ fs_initcall(cgroup_writeback_init);
 
 #else	/* CONFIG_CGROUP_WRITEBACK */
 
+static void bdi_down_write_wb_switch_rwsem(struct backing_dev_info *bdi) { }
+static void bdi_up_write_wb_switch_rwsem(struct backing_dev_info *bdi) { }
+
 static struct bdi_writeback *
 locked_inode_to_wb_and_lock_list(struct inode *inode)
 	__releases(&inode->i_lock)
@@ -2413,8 +2446,11 @@ void sync_inodes_sb(struct super_block *sb)
 		return;
 	WARN_ON(!rwsem_is_locked(&sb->s_umount));
 
+	/* protect against inode wb switch, see inode_switch_wbs_work_fn() */
+	bdi_down_write_wb_switch_rwsem(bdi);
 	bdi_split_work_to_wbs(bdi, &work, false);
 	wb_wait_for_completion(bdi, &done);
+	bdi_up_write_wb_switch_rwsem(bdi);
 
 	wait_sb_inodes(sb);
 }
diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index c31157135598..07e02d6df5ad 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -190,6 +190,7 @@ struct backing_dev_info {
 	struct radix_tree_root cgwb_tree; /* radix tree of active cgroup wbs */
 	struct rb_root cgwb_congested_tree; /* their congested states */
 	struct mutex cgwb_release_mutex;  /* protect shutdown of wb structs */
+	struct rw_semaphore wb_switch_rwsem; /* no cgwb switch while syncing */
 #else
 	struct bdi_writeback_congested *wb_congested;
 #endif
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 5c7e7f859a24..d66bf5f32610 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -287,7 +287,7 @@ enum req_opf {
 	REQ_OP_DISCARD		= 3,
 	/* securely erase sectors */
 	REQ_OP_SECURE_ERASE	= 5,
-	/* seset a zone write pointer */
+	/* reset a zone write pointer */
 	REQ_OP_ZONE_RESET	= 6,
 	/* write the same sector many times */
 	REQ_OP_WRITE_SAME	= 7,
diff --git a/include/uapi/linux/blkzoned.h b/include/uapi/linux/blkzoned.h
index 6fa38d001d84..498eec813494 100644
--- a/include/uapi/linux/blkzoned.h
+++ b/include/uapi/linux/blkzoned.h
@@ -138,6 +138,7 @@ struct blk_zone_range {
  * @BLKRESETZONE: Reset the write pointer of the zones in the specified
  *                sector range. The sector range must be zone aligned.
  * @BLKGETZONESZ: Get the device zone size in number of 512 B sectors.
+ * @BLKGETNRZONES: Get the total number of zones of the device.
  */
 #define BLKREPORTZONE	_IOWR(0x12, 130, struct blk_zone_report)
 #define BLKRESETZONE	_IOW(0x12, 131, struct blk_zone_range)
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 8a8bb8796c6c..72e6d0c55cfa 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -689,6 +689,7 @@ static int cgwb_bdi_init(struct backing_dev_info *bdi)
 	INIT_RADIX_TREE(&bdi->cgwb_tree, GFP_ATOMIC);
 	bdi->cgwb_congested_tree = RB_ROOT;
 	mutex_init(&bdi->cgwb_release_mutex);
+	init_rwsem(&bdi->wb_switch_rwsem);
 
 	ret = wb_init(&bdi->wb, bdi, 1, GFP_KERNEL);
 	if (!ret) {