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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: <IRQ> 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 </IRQ> 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 <thomas.tai@oracle.com> Reviewed-by: Eric Saint-Etienne <eric.saint.etienne@oracle.com> Signed-off-by: Karl Volz <karl.volz@oracle.com> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
80 lines
2.0 KiB
C
80 lines
2.0 KiB
C
/*
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* fault injection support for nvme.
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*
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* Copyright (c) 2018, Oracle and/or its affiliates
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*
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*/
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#include <linux/moduleparam.h>
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#include "nvme.h"
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static DECLARE_FAULT_ATTR(fail_default_attr);
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/* optional fault injection attributes boot time option:
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* nvme_core.fail_request=<interval>,<probability>,<space>,<times>
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*/
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static char *fail_request;
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module_param(fail_request, charp, 0000);
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void nvme_fault_inject_init(struct nvme_ns *ns)
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{
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struct dentry *dir, *parent;
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char *name = ns->disk->disk_name;
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struct nvme_fault_inject *fault_inj = &ns->fault_inject;
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struct fault_attr *attr = &fault_inj->attr;
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/* set default fault injection attribute */
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if (fail_request)
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setup_fault_attr(&fail_default_attr, fail_request);
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/* create debugfs directory and attribute */
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parent = debugfs_create_dir(name, NULL);
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if (!parent) {
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pr_warn("%s: failed to create debugfs directory\n", name);
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return;
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}
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*attr = fail_default_attr;
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dir = fault_create_debugfs_attr("fault_inject", parent, attr);
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if (IS_ERR(dir)) {
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pr_warn("%s: failed to create debugfs attr\n", name);
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debugfs_remove_recursive(parent);
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return;
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}
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ns->fault_inject.parent = parent;
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/* create debugfs for status code and dont_retry */
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fault_inj->status = NVME_SC_INVALID_OPCODE;
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fault_inj->dont_retry = true;
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debugfs_create_x16("status", 0600, dir, &fault_inj->status);
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debugfs_create_bool("dont_retry", 0600, dir, &fault_inj->dont_retry);
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}
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void nvme_fault_inject_fini(struct nvme_ns *ns)
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{
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/* remove debugfs directories */
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debugfs_remove_recursive(ns->fault_inject.parent);
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}
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void nvme_should_fail(struct request *req)
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{
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struct gendisk *disk = req->rq_disk;
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struct nvme_ns *ns = NULL;
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u16 status;
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/*
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* make sure this request is coming from a valid namespace
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*/
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if (!disk)
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return;
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ns = disk->private_data;
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if (ns && should_fail(&ns->fault_inject.attr, 1)) {
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/* inject status code and DNR bit */
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status = ns->fault_inject.status;
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if (ns->fault_inject.dont_retry)
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status |= NVME_SC_DNR;
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nvme_req(req)->status = status;
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}
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}
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EXPORT_SYMBOL_GPL(nvme_should_fail);
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