From b9e03857f2e22788db6ccb67512a6604a6b4f6db Mon Sep 17 00:00:00 2001 From: Thomas Tai Date: Thu, 8 Feb 2018 13:38:29 -0500 Subject: nvme: Add fault injection feature MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 --- drivers/nvme/host/fault_inject.c | 79 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 79 insertions(+) create mode 100644 drivers/nvme/host/fault_inject.c (limited to 'drivers/nvme/host/fault_inject.c') 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); -- cgit v1.2.3