diff options
Diffstat (limited to 'block/error-injection.c')
| -rw-r--r-- | block/error-injection.c | 315 |
1 files changed, 315 insertions, 0 deletions
diff --git a/block/error-injection.c b/block/error-injection.c new file mode 100644 index 000000000000..d24c90e9a25f --- /dev/null +++ b/block/error-injection.c @@ -0,0 +1,315 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2026 Christoph Hellwig. + */ +#include <linux/debugfs.h> +#include <linux/blkdev.h> +#include <linux/parser.h> +#include <linux/seq_file.h> +#include "blk.h" +#include "error-injection.h" + +struct blk_error_inject { + struct list_head entry; + sector_t start; + sector_t end; + enum req_op op; + blk_status_t status; + + /* only inject every 1 / chance times */ + unsigned int chance; +}; + +DEFINE_STATIC_KEY_FALSE(blk_error_injection_enabled); + +bool __blk_error_inject(struct bio *bio) +{ + struct gendisk *disk = bio->bi_bdev->bd_disk; + struct blk_error_inject *inj; + + rcu_read_lock(); + list_for_each_entry_rcu(inj, &disk->error_injection_list, entry) { + if (bio_op(bio) != inj->op) + continue; + /* + * This never matches 0-sized bios like empty WRITEs with + * REQ_PREFLUSH or ZONE_RESET_ALL. While adding a special case + * for them would be trivial, that means any WRITE rule would + * trigger for flushes. So before we can make this work + * properly, we'll need to start using REQ_OP_FLUSH for pure + * flushes at the bio level like we already do in blk-mq. + */ + if (bio->bi_iter.bi_sector > inj->end || + bio_end_sector(bio) <= inj->start) + continue; + if (inj->chance > 1 && (get_random_u32() % inj->chance) != 0) + continue; + + pr_info_ratelimited("%pg: injecting %s error for %s at sector %llu:%u\n", + disk->part0, blk_status_to_str(inj->status), + blk_op_str(inj->op), bio->bi_iter.bi_sector, + bio_sectors(bio)); + bio->bi_status = inj->status; + rcu_read_unlock(); + bio_endio(bio); + return true; + } + rcu_read_unlock(); + return false; +} + +static int error_inject_add(struct gendisk *disk, enum req_op op, + sector_t start, u64 nr_sectors, blk_status_t status, + unsigned int chance) +{ + struct blk_error_inject *inj; + int error = -EINVAL; + + if (op == REQ_OP_LAST) + return -EINVAL; + if (status == BLK_STS_OK) + return -EINVAL; + + inj = kzalloc_obj(*inj); + if (!inj) + return -ENOMEM; + + if (nr_sectors) { + if (U64_MAX - nr_sectors < start) + goto out_free_inj; + inj->end = start + nr_sectors - 1; + } else { + inj->end = U64_MAX; + } + + inj->op = op; + inj->start = start; + inj->status = status; + inj->chance = chance; + + pr_debug_ratelimited("%pg: adding %s injection for %s at sector %llu:%llu\n", + disk->part0, blk_status_to_str(status), + blk_op_str(op), + start, nr_sectors); + + /* + * Add to the front of the list so that newer entries can partially + * override other entries. This also intentionally allows duplicate + * entries as there is no real reason to reject them. + */ + mutex_lock(&disk->error_injection_lock); + if (!disk_live(disk)) { + mutex_unlock(&disk->error_injection_lock); + error = -ENODEV; + goto out_free_inj; + } + if (list_empty(&disk->error_injection_list)) + static_branch_inc(&blk_error_injection_enabled); + list_add_rcu(&inj->entry, &disk->error_injection_list); + set_bit(GD_ERROR_INJECT, &disk->state); + mutex_unlock(&disk->error_injection_lock); + return 0; + +out_free_inj: + kfree(inj); + return error; +} + +static void error_inject_removeall(struct gendisk *disk) +{ + struct blk_error_inject *inj; + + mutex_lock(&disk->error_injection_lock); + clear_bit(GD_ERROR_INJECT, &disk->state); + while ((inj = list_first_entry_or_null(&disk->error_injection_list, + struct blk_error_inject, entry))) { + list_del_rcu(&inj->entry); + kfree_rcu_mightsleep(inj); + } + static_branch_dec(&blk_error_injection_enabled); + mutex_unlock(&disk->error_injection_lock); +} + +enum options { + Opt_add = (1u << 0), + Opt_removeall = (1u << 1), + + Opt_op = (1u << 16), + Opt_start = (1u << 17), + Opt_nr_sectors = (1u << 18), + Opt_status = (1u << 19), + Opt_chance = (1u << 20), + + Opt_invalid, +}; + +static const match_table_t opt_tokens = { + { Opt_add, "add", }, + { Opt_removeall, "removeall", }, + { Opt_op, "op=%s", }, + { Opt_start, "start=%u" }, + { Opt_nr_sectors, "nr_sectors=%u" }, + { Opt_status, "status=%s" }, + { Opt_chance, "chance=%u" }, + { Opt_invalid, NULL, }, +}; + +static int match_op(substring_t *args, enum req_op *op) +{ + const char *tag; + + tag = match_strdup(args); + if (!tag) + return -ENOMEM; + *op = str_to_blk_op(tag); + if (*op == REQ_OP_LAST) + pr_warn("invalid op '%s'\n", tag); + kfree(tag); + return 0; +} + +static int match_status(substring_t *args, blk_status_t *status) +{ + const char *tag; + + tag = match_strdup(args); + if (!tag) + return -ENOMEM; + *status = tag_to_blk_status(tag); + if (!*status) + pr_warn("invalid status '%s'\n", tag); + kfree(tag); + return 0; +} + +static ssize_t blk_error_injection_parse_options(struct gendisk *disk, + char *options) +{ + enum { Unset, Add, Removeall } action = Unset; + unsigned int option_mask = 0, chance = 1; + enum req_op op = REQ_OP_LAST; + u64 start = 0, nr_sectors = 0; + blk_status_t status = BLK_STS_OK; + substring_t args[MAX_OPT_ARGS]; + char *p; + + while ((p = strsep(&options, ",\n")) != NULL) { + int error = 0; + ssize_t token; + + if (!*p) + continue; + token = match_token(p, opt_tokens, args); + option_mask |= token; + switch (token) { + case Opt_add: + if (action != Unset) + return -EINVAL; + action = Add; + break; + case Opt_removeall: + if (action != Unset) + return -EINVAL; + action = Removeall; + break; + case Opt_op: + error = match_op(args, &op); + break; + case Opt_start: + error = match_u64(args, &start); + break; + case Opt_nr_sectors: + error = match_u64(args, &nr_sectors); + break; + case Opt_status: + error = match_status(args, &status); + break; + case Opt_chance: + error = match_uint(args, &chance); + if (!error && chance == 0) + error = -EINVAL; + break; + default: + pr_warn("unknown parameter or missing value '%s'\n", p); + error = -EINVAL; + } + if (error) + return error; + } + + switch (action) { + case Add: + return error_inject_add(disk, op, start, nr_sectors, status, + chance); + case Removeall: + if (option_mask & ~Opt_removeall) + return -EINVAL; + error_inject_removeall(disk); + return 0; + default: + return -EINVAL; + } +} + +static ssize_t blk_error_injection_write(struct file *file, + const char __user *ubuf, size_t count, loff_t *pos) +{ + struct gendisk *disk = file_inode(file)->i_private; + char *options; + int error; + + options = memdup_user_nul(ubuf, count); + if (IS_ERR(options)) + return PTR_ERR(options); + error = blk_error_injection_parse_options(disk, options); + kfree(options); + + if (error) + return error; + return count; +} + +static int blk_error_injection_show(struct seq_file *s, void *private) +{ + struct gendisk *disk = s->private; + struct blk_error_inject *inj; + + rcu_read_lock(); + list_for_each_entry_rcu(inj, &disk->error_injection_list, entry) { + seq_printf(s, "%llu:%llu status=%s,chance=%u", + inj->start, inj->end, + blk_status_to_tag(inj->status), inj->chance); + seq_putc(s, '\n'); + } + rcu_read_unlock(); + return 0; +} + +static int blk_error_injection_open(struct inode *inode, struct file *file) +{ + return single_open(file, blk_error_injection_show, inode->i_private); +} + +static int blk_error_injection_release(struct inode *inode, struct file *file) +{ + return single_release(inode, file); +} + +static const struct file_operations blk_error_injection_fops = { + .owner = THIS_MODULE, + .write = blk_error_injection_write, + .read = seq_read, + .open = blk_error_injection_open, + .release = blk_error_injection_release, +}; + +void blk_error_injection_init(struct gendisk *disk) +{ + debugfs_create_file("error_injection", 0600, disk->queue->debugfs_dir, + disk, &blk_error_injection_fops); +} + +void blk_error_injection_exit(struct gendisk *disk) +{ + error_inject_removeall(disk); +} |