From: Thomas Tai Date: Thu, 8 Feb 2018 18:38:29 +0000 (-0500) Subject: nvme: Add fault injection feature X-Git-Tag: v4.17-rc1~113^2~67 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=b9e03857f2e22788db6ccb67512a6604a6b4f6db;p=linux.git nvme: Add fault injection feature Linux's fault injection framework provides a systematic way to support error injection via debugfs in the /sys/kernel/debug directory. This patch uses the framework to add error injection to NVMe driver. The fault injection source code is stored in a separate file and only linked if CONFIG_FAULT_INJECTION_DEBUG_FS kernel config is selected. Once the error injection is enabled, NVME_SC_INVALID_OPCODE with no retry will be injected into the nvme_end_request. Users can change the default status code and no retry flag via debufs. Following example shows how to enable and inject an error. For more examples, refer to Documentation/fault-injection/nvme-fault-injection.txt How to enable nvme fault injection: First, enable CONFIG_FAULT_INJECTION_DEBUG_FS kernel config, recompile the kernel. After booting up the kernel, do the following. How to inject an error: mount /dev/nvme0n1 /mnt echo 1 > /sys/kernel/debug/nvme0n1/fault_inject/times echo 100 > /sys/kernel/debug/nvme0n1/fault_inject/probability cp a.file /mnt Expected Result: cp: cannot stat ‘/mnt/a.file’: Input/output error Message from dmesg: FAULT_INJECTION: forcing a failure. name fault_inject, interval 1, probability 100, space 0, times 1 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.15.0-rc8+ #2 Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 Call Trace: dump_stack+0x5c/0x7d should_fail+0x148/0x170 nvme_should_fail+0x2f/0x50 [nvme_core] nvme_process_cq+0xe7/0x1d0 [nvme] nvme_irq+0x1e/0x40 [nvme] __handle_irq_event_percpu+0x3a/0x190 handle_irq_event_percpu+0x30/0x70 handle_irq_event+0x36/0x60 handle_fasteoi_irq+0x78/0x120 handle_irq+0xa7/0x130 ? tick_irq_enter+0xa8/0xc0 do_IRQ+0x43/0xc0 common_interrupt+0xa2/0xa2 RIP: 0010:native_safe_halt+0x2/0x10 RSP: 0018:ffffffff82003e90 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffdd RAX: ffffffff817a10c0 RBX: ffffffff82012480 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 000000008e38ce64 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff82012480 R13: ffffffff82012480 R14: 0000000000000000 R15: 0000000000000000 ? __sched_text_end+0x4/0x4 default_idle+0x18/0xf0 do_idle+0x150/0x1d0 cpu_startup_entry+0x6f/0x80 start_kernel+0x4c4/0x4e4 ? set_init_arg+0x55/0x55 secondary_startup_64+0xa5/0xb0 print_req_error: I/O error, dev nvme0n1, sector 9240 EXT4-fs error (device nvme0n1): ext4_find_entry:1436: inode #2: comm cp: reading directory lblock 0 Signed-off-by: Thomas Tai Reviewed-by: Eric Saint-Etienne Signed-off-by: Karl Volz Reviewed-by: Keith Busch Signed-off-by: Sagi Grimberg Signed-off-by: Jens Axboe --- diff --git a/drivers/nvme/host/Makefile b/drivers/nvme/host/Makefile index 441e67e3a9d7..aea459c65ae1 100644 --- a/drivers/nvme/host/Makefile +++ b/drivers/nvme/host/Makefile @@ -12,6 +12,7 @@ nvme-core-y := core.o nvme-core-$(CONFIG_TRACING) += trace.o nvme-core-$(CONFIG_NVME_MULTIPATH) += multipath.o nvme-core-$(CONFIG_NVM) += lightnvm.o +nvme-core-$(CONFIG_FAULT_INJECTION_DEBUG_FS) += fault_inject.o nvme-y += pci.o diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 24fd90f5fbfb..f96b99356917 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -3035,6 +3035,7 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid) nvme_mpath_add_disk(ns->head); nvme_mpath_add_disk_links(ns); + nvme_fault_inject_init(ns); return; out_unlink_ns: mutex_lock(&ctrl->subsys->lock); @@ -3053,6 +3054,7 @@ static void nvme_ns_remove(struct nvme_ns *ns) if (test_and_set_bit(NVME_NS_REMOVING, &ns->flags)) return; + nvme_fault_inject_fini(ns); if (ns->disk && ns->disk->flags & GENHD_FL_UP) { nvme_mpath_remove_disk_links(ns); sysfs_remove_group(&disk_to_dev(ns->disk)->kobj, diff --git a/drivers/nvme/host/fault_inject.c b/drivers/nvme/host/fault_inject.c new file mode 100644 index 000000000000..02632266ac06 --- /dev/null +++ b/drivers/nvme/host/fault_inject.c @@ -0,0 +1,79 @@ +/* + * fault injection support for nvme. + * + * Copyright (c) 2018, Oracle and/or its affiliates + * + */ + +#include +#include "nvme.h" + +static DECLARE_FAULT_ATTR(fail_default_attr); +/* optional fault injection attributes boot time option: + * nvme_core.fail_request=,,, + */ +static char *fail_request; +module_param(fail_request, charp, 0000); + +void nvme_fault_inject_init(struct nvme_ns *ns) +{ + struct dentry *dir, *parent; + char *name = ns->disk->disk_name; + struct nvme_fault_inject *fault_inj = &ns->fault_inject; + struct fault_attr *attr = &fault_inj->attr; + + /* set default fault injection attribute */ + if (fail_request) + setup_fault_attr(&fail_default_attr, fail_request); + + /* create debugfs directory and attribute */ + parent = debugfs_create_dir(name, NULL); + if (!parent) { + pr_warn("%s: failed to create debugfs directory\n", name); + return; + } + + *attr = fail_default_attr; + dir = fault_create_debugfs_attr("fault_inject", parent, attr); + if (IS_ERR(dir)) { + pr_warn("%s: failed to create debugfs attr\n", name); + debugfs_remove_recursive(parent); + return; + } + ns->fault_inject.parent = parent; + + /* create debugfs for status code and dont_retry */ + fault_inj->status = NVME_SC_INVALID_OPCODE; + fault_inj->dont_retry = true; + debugfs_create_x16("status", 0600, dir, &fault_inj->status); + debugfs_create_bool("dont_retry", 0600, dir, &fault_inj->dont_retry); +} + +void nvme_fault_inject_fini(struct nvme_ns *ns) +{ + /* remove debugfs directories */ + debugfs_remove_recursive(ns->fault_inject.parent); +} + +void nvme_should_fail(struct request *req) +{ + struct gendisk *disk = req->rq_disk; + struct nvme_ns *ns = NULL; + u16 status; + + /* + * make sure this request is coming from a valid namespace + */ + if (!disk) + return; + + ns = disk->private_data; + if (ns && should_fail(&ns->fault_inject.attr, 1)) { + /* inject status code and DNR bit */ + status = ns->fault_inject.status; + if (ns->fault_inject.dont_retry) + status |= NVME_SC_DNR; + nvme_req(req)->status = status; + } +} +EXPORT_SYMBOL_GPL(nvme_should_fail); diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index 0521e4707d1c..9a3d3540aa6a 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -21,6 +21,7 @@ #include #include #include +#include extern unsigned int nvme_io_timeout; #define NVME_IO_TIMEOUT (nvme_io_timeout * HZ) @@ -261,6 +262,15 @@ struct nvme_ns_head { int instance; }; +#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS +struct nvme_fault_inject { + struct fault_attr attr; + struct dentry *parent; + bool dont_retry; /* DNR, do not retry */ + u16 status; /* status code */ +}; +#endif + struct nvme_ns { struct list_head list; @@ -282,6 +292,11 @@ struct nvme_ns { #define NVME_NS_REMOVING 0 #define NVME_NS_DEAD 1 u16 noiob; + +#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS + struct nvme_fault_inject fault_inject; +#endif + }; struct nvme_ctrl_ops { @@ -300,6 +315,16 @@ struct nvme_ctrl_ops { int (*reinit_request)(void *data, struct request *rq); }; +#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS +void nvme_fault_inject_init(struct nvme_ns *ns); +void nvme_fault_inject_fini(struct nvme_ns *ns); +void nvme_should_fail(struct request *req); +#else +static inline void nvme_fault_inject_init(struct nvme_ns *ns) {} +static inline void nvme_fault_inject_fini(struct nvme_ns *ns) {} +static inline void nvme_should_fail(struct request *req) {} +#endif + static inline bool nvme_ctrl_ready(struct nvme_ctrl *ctrl) { u32 val = 0; @@ -336,6 +361,8 @@ static inline void nvme_end_request(struct request *req, __le16 status, rq->status = le16_to_cpu(status) >> 1; rq->result = result; + /* inject error when permitted by fault injection framework */ + nvme_should_fail(req); blk_mq_complete_request(req); }