[PATCH for-rc 05/24] block/rnbd-clt: Inject some fault points

[Gioh Kim <gi-oh.kim@ionos.com>]

From: Gioh Kim <gi-oh.kim@cloud.ionos.com>

This patch injects two fault points:
1. generate an IO error
2. generate a unmap failure

Signed-off-by: Gioh Kim <gi-oh.kim@cloud.ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
---
 drivers/block/rnbd/rnbd-clt-sysfs.c | 53 +++++++++++++++++++++++++++++
 drivers/block/rnbd/rnbd-clt.c       | 17 +++++++++
 drivers/block/rnbd/rnbd-clt.h       | 15 ++++++++
 3 files changed, 85 insertions(+)

diff --git a/drivers/block/rnbd/rnbd-clt-sysfs.c b/drivers/block/rnbd/rnbd-clt-sysfs.c
index d4aa6bfc9555..d83415875960 100644
--- a/drivers/block/rnbd/rnbd-clt-sysfs.c
+++ b/drivers/block/rnbd/rnbd-clt-sysfs.c
@@ -651,3 +651,56 @@ void rnbd_clt_destroy_sysfs_files(void)
 	device_destroy(rnbd_dev_class, MKDEV(0, 0));
 	class_destroy(rnbd_dev_class);
 }
+
+#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
+void rnbd_clt_fault_inject_init(struct rnbd_clt_fault_inject *fault_inject,
+				const char *dev_name)
+{
+	rnbd_fault_inject_init(&fault_inject->fj, dev_name, -EBUSY);
+	/* injection points */
+	rnbd_fault_inject_add(fault_inject->fj.dir,
+			      "fail-request", &fault_inject->fail_request);
+	rnbd_fault_inject_add(fault_inject->fj.dir,
+			      "fail-unmap", &fault_inject->fail_unmap);
+}
+
+void rnbd_clt_fault_inject_final(struct rnbd_clt_fault_inject *fault_inject)
+{
+	rnbd_fault_inject_final(&fault_inject->fj);
+}
+
+int rnbd_clt_should_fail_request(struct request *req)
+{
+	struct rnbd_clt_dev *dev = req->rq_disk->private_data;
+	struct rnbd_clt_fault_inject *fault_inject = &dev->fault_inject;
+
+	if (fault_inject->fail_request && should_fail(&fault_inject->fj.attr, 1))
+		return fault_inject->fj.status;
+	return 0;
+}
+
+int rnbd_clt_should_fail_unmap(struct rnbd_clt_dev *dev)
+{
+	struct rnbd_clt_fault_inject *fault_inject = &dev->fault_inject;
+
+	if (fault_inject->fail_unmap && should_fail(&fault_inject->fj.attr, 1))
+		return fault_inject->fj.status;
+	return 0;
+}
+#else
+void rnbd_clt_fault_inject_init(struct rnbd_clt_fault_inject *fault_inj,
+				const char *dev_name)
+{
+}
+void rnbd_clt_fault_inject_final(struct rnbd_clt_fault_inject *fault_inject)
+{
+}
+int rnbd_clt_should_fail_request(struct request *req)
+{
+	return 0;
+}
+int rnbd_clt_should_fail_unmap(struct rnbd_clt_dev *dev)
+{
+	return 0;
+}
+#endif
diff --git a/drivers/block/rnbd/rnbd-clt.c b/drivers/block/rnbd/rnbd-clt.c
index 45a470076652..8c9a02c8b8bd 100644
--- a/drivers/block/rnbd/rnbd-clt.c
+++ b/drivers/block/rnbd/rnbd-clt.c
@@ -411,6 +411,11 @@ static void msg_io_conf(void *priv, int errno)
 	struct rnbd_clt_dev *dev = iu->dev;
 	struct request *rq = iu->rq;
 	int rw = rq_data_dir(rq);
+	int fail_err = 0;
+
+	fail_err = rnbd_clt_should_fail_request(rq);
+	if (unlikely(fail_err)) /* over-write error */
+		errno = fail_err;
 
 	iu->errno = errno;
 
@@ -1161,6 +1166,7 @@ static blk_status_t rnbd_queue_rq(struct blk_mq_hw_ctx *hctx,
 	}
 
 	blk_mq_start_request(rq);
+
 	err = rnbd_client_xfer_request(dev, rq, iu);
 	if (likely(err == 0))
 		return BLK_STS_OK;
@@ -1545,6 +1551,8 @@ struct rnbd_clt_dev *rnbd_clt_map_device(const char *sessname,
 		goto send_close;
 	}
 
+	rnbd_clt_fault_inject_init(&dev->fault_inject, dev->gd->disk_name);
+
 	rnbd_clt_info(dev,
 		       "map_device: Device mapped as %s (nsectors: %zu, logical_block_size: %d, physical_block_size: %d, max_write_same_sectors: %d, max_discard_sectors: %d, discard_granularity: %d, discard_alignment: %d, secure_discard: %d, max_segments: %d, max_hw_sectors: %d, rotational: %d, wc: %d, fua: %d)\n",
 		       dev->gd->disk_name, dev->nsectors,
@@ -1599,8 +1607,16 @@ int rnbd_clt_unmap_device(struct rnbd_clt_dev *dev, bool force,
 	struct rnbd_clt_session *sess = dev->sess;
 	int refcount, ret = 0;
 	bool was_mapped;
+	int fail_err = 0;
 
 	mutex_lock(&dev->lock);
+
+	fail_err = rnbd_clt_should_fail_unmap(dev);
+	if (unlikely(fail_err)) {
+		ret = fail_err;
+		goto err;
+	}
+
 	if (dev->dev_state == DEV_STATE_UNMAPPED) {
 		rnbd_clt_info(dev, "Device is already being unmapped\n");
 		ret = -EALREADY;
@@ -1618,6 +1634,7 @@ int rnbd_clt_unmap_device(struct rnbd_clt_dev *dev, bool force,
 	dev->dev_state = DEV_STATE_UNMAPPED;
 	mutex_unlock(&dev->lock);
 
+	rnbd_clt_fault_inject_final(&dev->fault_inject);
 	delete_dev(dev);
 	destroy_sysfs(dev, sysfs_self);
 	destroy_gen_disk(dev);
diff --git a/drivers/block/rnbd/rnbd-clt.h b/drivers/block/rnbd/rnbd-clt.h
index 537d499dad3b..5ecbe8dedf24 100644
--- a/drivers/block/rnbd/rnbd-clt.h
+++ b/drivers/block/rnbd/rnbd-clt.h
@@ -107,6 +107,14 @@ struct rnbd_queue {
 	struct blk_mq_hw_ctx	*hctx;
 };
 
+struct rnbd_clt_fault_inject {
+#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
+	struct rnbd_fault_inject fj;
+	bool fail_unmap;
+	bool fail_request;
+#endif
+};
+
 struct rnbd_clt_dev {
 	struct rnbd_clt_session	*sess;
 	struct request_queue	*queue;
@@ -139,6 +147,7 @@ struct rnbd_clt_dev {
 	char			*blk_symlink_name;
 	refcount_t		refcount;
 	struct work_struct	unmap_on_rmmod_work;
+	struct rnbd_clt_fault_inject fault_inject;
 };
 
 /* rnbd-clt.c */
@@ -163,4 +172,10 @@ void rnbd_clt_destroy_default_group(void);
 
 void rnbd_clt_remove_dev_symlink(struct rnbd_clt_dev *dev);
 
+void rnbd_clt_fault_inject_init(struct rnbd_clt_fault_inject *fault_inj,
+			    const char *dev_name);
+void rnbd_clt_fault_inject_final(struct rnbd_clt_fault_inject *fault_inject);
+int rnbd_clt_should_fail_request(struct request *req);
+int rnbd_clt_should_fail_unmap(struct rnbd_clt_dev *dev);
+int rnbd_clt_should_fail_request_timeout(struct request *req);
 #endif /* RNBD_CLT_H */
-- 
2.25.1