6ff1cb355e
This patch provides base functions implement to fault-injection capabilities. - The function should_fail() is taken from failmalloc-1.0 (http://www.nongnu.org/failmalloc/) [akpm@osdl.org: cleanups, comments, add __init] Cc: <okuji@enbug.org> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Don Mullis <dwm@meer.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
183 lines
4.2 KiB
C
183 lines
4.2 KiB
C
#include <linux/kernel.h>
|
|
#include <linux/init.h>
|
|
#include <linux/random.h>
|
|
#include <linux/stat.h>
|
|
#include <linux/types.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/module.h>
|
|
#include <linux/fault-inject.h>
|
|
|
|
/*
|
|
* setup_fault_attr() is a helper function for various __setup handlers, so it
|
|
* returns 0 on error, because that is what __setup handlers do.
|
|
*/
|
|
int __init setup_fault_attr(struct fault_attr *attr, char *str)
|
|
{
|
|
unsigned long probability;
|
|
unsigned long interval;
|
|
int times;
|
|
int space;
|
|
|
|
/* "<interval>,<probability>,<space>,<times>" */
|
|
if (sscanf(str, "%lu,%lu,%d,%d",
|
|
&interval, &probability, &space, ×) < 4) {
|
|
printk(KERN_WARNING
|
|
"FAULT_INJECTION: failed to parse arguments\n");
|
|
return 0;
|
|
}
|
|
|
|
attr->probability = probability;
|
|
attr->interval = interval;
|
|
atomic_set(&attr->times, times);
|
|
atomic_set(&attr->space, space);
|
|
|
|
return 1;
|
|
}
|
|
|
|
static void fail_dump(struct fault_attr *attr)
|
|
{
|
|
if (attr->verbose > 0)
|
|
printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure\n");
|
|
if (attr->verbose > 1)
|
|
dump_stack();
|
|
}
|
|
|
|
#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)
|
|
|
|
/*
|
|
* This code is stolen from failmalloc-1.0
|
|
* http://www.nongnu.org/failmalloc/
|
|
*/
|
|
|
|
int should_fail(struct fault_attr *attr, ssize_t size)
|
|
{
|
|
if (atomic_read(&attr->times) == 0)
|
|
return 0;
|
|
|
|
if (atomic_read(&attr->space) > size) {
|
|
atomic_sub(size, &attr->space);
|
|
return 0;
|
|
}
|
|
|
|
if (attr->interval > 1) {
|
|
attr->count++;
|
|
if (attr->count % attr->interval)
|
|
return 0;
|
|
}
|
|
|
|
if (attr->probability > random32() % 100)
|
|
goto fail;
|
|
|
|
return 0;
|
|
|
|
fail:
|
|
fail_dump(attr);
|
|
|
|
if (atomic_read(&attr->times) != -1)
|
|
atomic_dec_not_zero(&attr->times);
|
|
|
|
return 1;
|
|
}
|
|
|
|
#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
|
|
|
|
static void debugfs_ul_set(void *data, u64 val)
|
|
{
|
|
*(unsigned long *)data = val;
|
|
}
|
|
|
|
static u64 debugfs_ul_get(void *data)
|
|
{
|
|
return *(unsigned long *)data;
|
|
}
|
|
|
|
DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
|
|
|
|
static struct dentry *debugfs_create_ul(const char *name, mode_t mode,
|
|
struct dentry *parent, unsigned long *value)
|
|
{
|
|
return debugfs_create_file(name, mode, parent, value, &fops_ul);
|
|
}
|
|
|
|
static void debugfs_atomic_t_set(void *data, u64 val)
|
|
{
|
|
atomic_set((atomic_t *)data, val);
|
|
}
|
|
|
|
static u64 debugfs_atomic_t_get(void *data)
|
|
{
|
|
return atomic_read((atomic_t *)data);
|
|
}
|
|
|
|
DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
|
|
debugfs_atomic_t_set, "%lld\n");
|
|
|
|
static struct dentry *debugfs_create_atomic_t(const char *name, mode_t mode,
|
|
struct dentry *parent, atomic_t *value)
|
|
{
|
|
return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
|
|
}
|
|
|
|
void cleanup_fault_attr_dentries(struct fault_attr *attr)
|
|
{
|
|
debugfs_remove(attr->dentries.probability_file);
|
|
attr->dentries.probability_file = NULL;
|
|
|
|
debugfs_remove(attr->dentries.interval_file);
|
|
attr->dentries.interval_file = NULL;
|
|
|
|
debugfs_remove(attr->dentries.times_file);
|
|
attr->dentries.times_file = NULL;
|
|
|
|
debugfs_remove(attr->dentries.space_file);
|
|
attr->dentries.space_file = NULL;
|
|
|
|
debugfs_remove(attr->dentries.verbose_file);
|
|
attr->dentries.verbose_file = NULL;
|
|
|
|
if (attr->dentries.dir)
|
|
WARN_ON(!simple_empty(attr->dentries.dir));
|
|
|
|
debugfs_remove(attr->dentries.dir);
|
|
attr->dentries.dir = NULL;
|
|
}
|
|
|
|
int init_fault_attr_dentries(struct fault_attr *attr, const char *name)
|
|
{
|
|
mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
|
|
struct dentry *dir;
|
|
|
|
memset(&attr->dentries, 0, sizeof(attr->dentries));
|
|
|
|
dir = debugfs_create_dir(name, NULL);
|
|
if (!dir)
|
|
goto fail;
|
|
attr->dentries.dir = dir;
|
|
|
|
attr->dentries.probability_file =
|
|
debugfs_create_ul("probability", mode, dir, &attr->probability);
|
|
|
|
attr->dentries.interval_file =
|
|
debugfs_create_ul("interval", mode, dir, &attr->interval);
|
|
|
|
attr->dentries.times_file =
|
|
debugfs_create_atomic_t("times", mode, dir, &attr->times);
|
|
|
|
attr->dentries.space_file =
|
|
debugfs_create_atomic_t("space", mode, dir, &attr->space);
|
|
|
|
attr->dentries.verbose_file =
|
|
debugfs_create_ul("verbose", mode, dir, &attr->verbose);
|
|
|
|
if (!attr->dentries.probability_file || !attr->dentries.interval_file
|
|
|| !attr->dentries.times_file || !attr->dentries.space_file
|
|
|| !attr->dentries.verbose_file)
|
|
goto fail;
|
|
|
|
return 0;
|
|
fail:
|
|
cleanup_fault_attr_dentries(attr);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
|