f2fs: add fault injection to sysfs

This patch introduces a new struct f2fs_fault_info and a global f2fs_fault
to save fault injection status. Fault injection entries are created in
/sys/fs/f2fs/fault_injection/ during initializing f2fs module.

Signed-off-by: Sheng Yong <shengyong1@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/f2fs.h

@@ -48,15 +48,36 @@ enum {
 	FAULT_MAX,
 };
 
-extern u32 f2fs_fault_rate;
-extern atomic_t f2fs_ops;
+struct f2fs_fault_info {
+	atomic_t inject_ops;
+	unsigned int inject_rate;
+	unsigned int inject_type;
+};
+
+extern struct f2fs_fault_info f2fs_fault;
 extern char *fault_name[FAULT_MAX];
+#define IS_FAULT_SET(type) (f2fs_fault.inject_type & (1 << (type)))
 
 static inline bool time_to_inject(int type)
 {
-	atomic_inc(&f2fs_ops);
-	if (f2fs_fault_rate && (atomic_read(&f2fs_ops) >= f2fs_fault_rate)) {
-		atomic_set(&f2fs_ops, 0);
+	if (!f2fs_fault.inject_rate)
+		return false;
+	if (type == FAULT_KMALLOC && !IS_FAULT_SET(type))
+		return false;
+	else if (type == FAULT_PAGE_ALLOC && !IS_FAULT_SET(type))
+		return false;
+	else if (type == FAULT_ALLOC_NID && !IS_FAULT_SET(type))
+		return false;
+	else if (type == FAULT_ORPHAN && !IS_FAULT_SET(type))
+		return false;
+	else if (type == FAULT_BLOCK && !IS_FAULT_SET(type))
+		return false;
+	else if (type == FAULT_DIR_DEPTH && !IS_FAULT_SET(type))
+		return false;
+
+	atomic_inc(&f2fs_fault.inject_ops);
+	if (atomic_read(&f2fs_fault.inject_ops) >= f2fs_fault.inject_rate) {
+		atomic_set(&f2fs_fault.inject_ops, 0);
 		printk("%sF2FS-fs : inject %s in %pF\n",
 				KERN_INFO,
 				fault_name[type],

fs/f2fs/super.c

@@ -40,8 +40,7 @@ static struct kmem_cache *f2fs_inode_cachep;
 static struct kset *f2fs_kset;
 
 #ifdef CONFIG_F2FS_FAULT_INJECTION
-u32 f2fs_fault_rate = 0;
-atomic_t f2fs_ops;
+struct f2fs_fault_info f2fs_fault;
 
 char *fault_name[FAULT_MAX] = {
 	[FAULT_KMALLOC]		= "kmalloc",
@@ -51,6 +50,17 @@ char *fault_name[FAULT_MAX] = {
 	[FAULT_BLOCK]		= "no more block",
 	[FAULT_DIR_DEPTH]	= "too big dir depth",
 };
+
+static void f2fs_build_fault_attr(unsigned int rate)
+{
+	if (rate) {
+		atomic_set(&f2fs_fault.inject_ops, 0);
+		f2fs_fault.inject_rate = rate;
+		f2fs_fault.inject_type = (1 << FAULT_MAX) - 1;
+	} else {
+		memset(&f2fs_fault, 0, sizeof(struct f2fs_fault_info));
+	}
+}
 #endif
 
 /* f2fs-wide shrinker description */
@@ -118,6 +128,10 @@ enum {
 	SM_INFO,	/* struct f2fs_sm_info */
 	NM_INFO,	/* struct f2fs_nm_info */
 	F2FS_SBI,	/* struct f2fs_sb_info */
+#ifdef CONFIG_F2FS_FAULT_INJECTION
+	FAULT_INFO_RATE,	/* struct f2fs_fault_info */
+	FAULT_INFO_TYPE,	/* struct f2fs_fault_info */
+#endif
 };
 
 struct f2fs_attr {
@@ -139,6 +153,11 @@ static unsigned char *__struct_ptr(struct f2fs_sb_info *sbi, int struct_type)
 		return (unsigned char *)NM_I(sbi);
 	else if (struct_type == F2FS_SBI)
 		return (unsigned char *)sbi;
+#ifdef CONFIG_F2FS_FAULT_INJECTION
+	else if (struct_type == FAULT_INFO_RATE ||
+					struct_type == FAULT_INFO_TYPE)
+		return (unsigned char *)&f2fs_fault;
+#endif
 	return NULL;
 }
 
@@ -188,6 +207,10 @@ static ssize_t f2fs_sbi_store(struct f2fs_attr *a,
 	ret = kstrtoul(skip_spaces(buf), 0, &t);
 	if (ret < 0)
 		return ret;
+#ifdef CONFIG_F2FS_FAULT_INJECTION
+	if (a->struct_type == FAULT_INFO_TYPE && t >= (1 << FAULT_MAX))
+		return -EINVAL;
+#endif
 	*ui = t;
 	return count;
 }
@@ -253,6 +276,10 @@ F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, max_victim_search, max_victim_search);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, dir_level, dir_level);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, cp_interval, interval_time[CP_TIME]);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, idle_interval, interval_time[REQ_TIME]);
+#ifdef CONFIG_F2FS_FAULT_INJECTION
+F2FS_RW_ATTR(FAULT_INFO_RATE, f2fs_fault_info, inject_rate, inject_rate);
+F2FS_RW_ATTR(FAULT_INFO_TYPE, f2fs_fault_info, inject_type, inject_type);
+#endif
 F2FS_GENERAL_RO_ATTR(lifetime_write_kbytes);
 
 #define ATTR_LIST(name) (&f2fs_attr_##name.attr)
@@ -289,6 +316,22 @@ static struct kobj_type f2fs_ktype = {
 	.release	= f2fs_sb_release,
 };
 
+#ifdef CONFIG_F2FS_FAULT_INJECTION
+/* sysfs for f2fs fault injection */
+static struct kobject f2fs_fault_inject;
+
+static struct attribute *f2fs_fault_attrs[] = {
+	ATTR_LIST(inject_rate),
+	ATTR_LIST(inject_type),
+	NULL
+};
+
+static struct kobj_type f2fs_fault_ktype = {
+	.default_attrs	= f2fs_fault_attrs,
+	.sysfs_ops	= &f2fs_attr_ops,
+};
+#endif
+
 void f2fs_msg(struct super_block *sb, const char *level, const char *fmt, ...)
 {
 	struct va_format vaf;
@@ -317,8 +360,9 @@ static int parse_options(struct super_block *sb, char *options)
 	int arg = 0;
 
 #ifdef CONFIG_F2FS_FAULT_INJECTION
-	f2fs_fault_rate = 0;
+	f2fs_build_fault_attr(0);
 #endif
+
 	if (!options)
 		return 0;
 
@@ -456,8 +500,7 @@ static int parse_options(struct super_block *sb, char *options)
 			if (args->from && match_int(args, &arg))
 				return -EINVAL;
 #ifdef CONFIG_F2FS_FAULT_INJECTION
-			f2fs_fault_rate = arg;
-			atomic_set(&f2fs_ops, 0);
+			f2fs_build_fault_attr(arg);
 #else
 			f2fs_msg(sb, KERN_INFO,
 				"FAULT_INJECTION was not selected");
@@ -1797,6 +1840,16 @@ static int __init init_f2fs_fs(void)
 		err = -ENOMEM;
 		goto free_extent_cache;
 	}
+#ifdef CONFIG_F2FS_FAULT_INJECTION
+	f2fs_fault_inject.kset = f2fs_kset;
+	f2fs_build_fault_attr(0);
+	err = kobject_init_and_add(&f2fs_fault_inject, &f2fs_fault_ktype,
+				NULL, "fault_injection");
+	if (err) {
+		f2fs_fault_inject.kset = NULL;
+		goto free_kset;
+	}
+#endif
 	err = register_shrinker(&f2fs_shrinker_info);
 	if (err)
 		goto free_kset;
@@ -1815,6 +1868,10 @@ free_filesystem:
 free_shrinker:
 	unregister_shrinker(&f2fs_shrinker_info);
 free_kset:
+#ifdef CONFIG_F2FS_FAULT_INJECTION
+	if (f2fs_fault_inject.kset)
+		kobject_put(&f2fs_fault_inject);
+#endif
 	kset_unregister(f2fs_kset);
 free_extent_cache:
 	destroy_extent_cache();
@@ -1841,6 +1898,9 @@ static void __exit exit_f2fs_fs(void)
 	destroy_segment_manager_caches();
 	destroy_node_manager_caches();
 	destroy_inodecache();
+#ifdef CONFIG_F2FS_FAULT_INJECTION
+	kobject_put(&f2fs_fault_inject);
+#endif
 	kset_unregister(f2fs_kset);
 	f2fs_destroy_trace_ios();
 }