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block: null_blk: make fault-injection dynamically configurable per device 

The null_blk driver has multiple driver-specific fault injection
mechanisms.  Each fault injection configuration can only be specified by a
module parameter and cannot be reconfigured without reloading the driver.
Also, each configuration is common to all devices and is initialized every
time a new device is added.

This change adds the following subdirectories for each null_blk device.

/sys/kernel/config/nullb/<disk>/timeout_inject
/sys/kernel/config/nullb/<disk>/requeue_inject
/sys/kernel/config/nullb/<disk>/init_hctx_fault_inject

Each fault injection attribute can be dynamically set per device by a
corresponding file in these directories.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Link: https://lore.kernel.org/r/20230327143733.14599-3-akinobu.mita@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Akinobu Mita 2023-03-27 23:37:33 +09:00 committed by Jens Axboe
parent 4668c7a294
commit bb4c19e030
4 changed files with 87 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
Documentation/fault-injection/fault-injection.rst
View File

@ -52,6 +52,14 @@ Available fault injection capabilities
status code is NVME_SC_INVALID_OPCODE with no retry. The status code and
retry flag can be set via the debugfs.
- Null test block driver fault injection
inject IO timeouts by setting config items under
/sys/kernel/config/nullb/<disk>/timeout_inject,
inject requeue requests by setting config items under
/sys/kernel/config/nullb/<disk>/requeue_inject, and
inject init_hctx() errors by setting config items under
/sys/kernel/config/nullb/<disk>/init_hctx_fault_inject.
Configure fault-injection capabilities behavior
-----------------------------------------------

2
drivers/block/null_blk/Kconfig
View File

@ -9,4 +9,4 @@ config BLK_DEV_NULL_BLK
config BLK_DEV_NULL_BLK_FAULT_INJECTION
bool "Support fault injection for Null test block driver"
depends on BLK_DEV_NULL_BLK && FAULT_INJECTION
depends on BLK_DEV_NULL_BLK && FAULT_INJECTION_CONFIGFS

93
drivers/block/null_blk/main.c
View File

@ -250,7 +250,7 @@ static void null_free_device_storage(struct nullb_device *dev, bool is_cache);
static inline struct nullb_device *to_nullb_device(struct config_item *item)
{
return item ? container_of(item, struct nullb_device, item) : NULL;
return item ? container_of(to_config_group(item), struct nullb_device, group) : NULL;
}
static inline ssize_t nullb_device_uint_attr_show(unsigned int val, char *page)
@ -593,8 +593,29 @@ static const struct config_item_type nullb_device_type = {
.ct_owner = THIS_MODULE,
};
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
static void nullb_add_fault_config(struct nullb_device *dev)
{
fault_config_init(&dev->timeout_config, "timeout_inject");
fault_config_init(&dev->requeue_config, "requeue_inject");
fault_config_init(&dev->init_hctx_fault_config, "init_hctx_fault_inject");
configfs_add_default_group(&dev->timeout_config.group, &dev->group);
configfs_add_default_group(&dev->requeue_config.group, &dev->group);
configfs_add_default_group(&dev->init_hctx_fault_config.group, &dev->group);
}
#else
static void nullb_add_fault_config(struct nullb_device *dev)
{
}
#endif
static struct
config_item *nullb_group_make_item(struct config_group *group, const char *name)
config_group *nullb_group_make_group(struct config_group *group, const char *name)
{
struct nullb_device *dev;
@ -605,9 +626,10 @@ config_item *nullb_group_make_item(struct config_group *group, const char *name)
if (!dev)
return ERR_PTR(-ENOMEM);
config_item_init_type_name(&dev->item, name, &nullb_device_type);
config_group_init_type_name(&dev->group, name, &nullb_device_type);
nullb_add_fault_config(dev);
return &dev->item;
return &dev->group;
}
static void
@ -645,7 +667,7 @@ static struct configfs_attribute *nullb_group_attrs[] = {
};
static struct configfs_group_operations nullb_group_ops = {
.make_item = nullb_group_make_item,
.make_group = nullb_group_make_group,
.drop_item = nullb_group_drop_item,
};
@ -676,6 +698,13 @@ static struct nullb_device *null_alloc_dev(void)
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev)
return NULL;
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
dev->timeout_config.attr = null_timeout_attr;
dev->requeue_config.attr = null_requeue_attr;
dev->init_hctx_fault_config.attr = null_init_hctx_attr;
#endif
INIT_RADIX_TREE(&dev->data, GFP_ATOMIC);
INIT_RADIX_TREE(&dev->cache, GFP_ATOMIC);
if (badblocks_init(&dev->badblocks, 0)) {
@ -1515,24 +1544,48 @@ static void null_submit_bio(struct bio *bio)
null_handle_cmd(alloc_cmd(nq, bio), sector, nr_sectors, bio_op(bio));
}
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
static bool should_timeout_request(struct request *rq)
{
struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
struct nullb_device *dev = cmd->nq->dev;
return should_fail(&dev->timeout_config.attr, 1);
}
static bool should_requeue_request(struct request *rq)
{
struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
struct nullb_device *dev = cmd->nq->dev;
return should_fail(&dev->requeue_config.attr, 1);
}
static bool should_init_hctx_fail(struct nullb_device *dev)
{
return should_fail(&dev->init_hctx_fault_config.attr, 1);
}
#else
static bool should_timeout_request(struct request *rq)
{
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
if (g_timeout_str[0])
return should_fail(&null_timeout_attr, 1);
#endif
return false;
}
static bool should_requeue_request(struct request *rq)
{
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
if (g_requeue_str[0])
return should_fail(&null_requeue_attr, 1);
#endif
return false;
}
static bool should_init_hctx_fail(struct nullb_device *dev)
{
return false;
}
#endif
static void null_map_queues(struct blk_mq_tag_set *set)
{
struct nullb *nullb = set->driver_data;
@ -1729,10 +1782,8 @@ static int null_init_hctx(struct blk_mq_hw_ctx *hctx, void *driver_data,
struct nullb *nullb = hctx->queue->queuedata;
struct nullb_queue *nq;
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
if (g_init_hctx_str[0] && should_fail(&null_init_hctx_attr, 1))
if (should_init_hctx_fail(nullb->dev))
return -EFAULT;
#endif
nq = &nullb->queues[hctx_idx];
hctx->driver_data = nq;
@ -2052,9 +2103,6 @@ static int null_add_dev(struct nullb_device *dev)
if (rv)
goto out_cleanup_queues;
if (!null_setup_fault())
goto out_cleanup_tags;
nullb->tag_set->timeout = 5 * HZ;
nullb->disk = blk_mq_alloc_disk(nullb->tag_set, nullb);
if (IS_ERR(nullb->disk)) {
@ -2116,10 +2164,10 @@ static int null_add_dev(struct nullb_device *dev)
null_config_discard(nullb);
if (config_item_name(&dev->item)) {
if (config_item_name(&dev->group.cg_item)) {
/* Use configfs dir name as the device name */
snprintf(nullb->disk_name, sizeof(nullb->disk_name),
"%s", config_item_name(&dev->item));
"%s", config_item_name(&dev->group.cg_item));
} else {
sprintf(nullb->disk_name, "nullb%d", nullb->index);
}
@ -2219,6 +2267,9 @@ static int __init null_init(void)
g_home_node = NUMA_NO_NODE;
}
if (!null_setup_fault())
return -EINVAL;
if (g_queue_mode == NULL_Q_RQ) {
pr_err("legacy IO path is no longer available\n");
return -EINVAL;

7
drivers/block/null_blk/null_blk.h
View File

@ -69,7 +69,12 @@ enum {
struct nullb_device {
struct nullb *nullb;
struct config_item item;
struct config_group group;
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
struct fault_config timeout_config;
struct fault_config requeue_config;
struct fault_config init_hctx_fault_config;
#endif
struct radix_tree_root data; /* data stored in the disk */
struct radix_tree_root cache; /* disk cache data */
unsigned long flags; /* device flags */