[RFC PATCH 3/4] f2fs: add sysfs interfaces for fault injection

[Sheng Yong <shengyong1@huawei.com>]

This patch adds a new entry called fault_injection in /sys/fs/f2fs, and
all injection attributes are placed in this entry.  During initializing
f2fs module, these inject attributes are created.

Signed-off-by: Sheng Yong <shengyong1@huawei.com>
---
 fs/f2fs/super.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 069dc44..a9066e4 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -52,6 +52,12 @@ char *fault_name[FAULT_MAX] = {
 	[FAULT_BLOCK]		= "no more block",
 	[FAULT_DIR_DEPTH]	= "too big dir depth",
 };
+
+static int f2fs_build_fault_attr(void)
+{
+	memset(&f2fs_fault, 0, sizeof(struct f2fs_fault_info));
+	return 0;
+}
 #endif
 
 /* f2fs-wide shrinker description */
@@ -119,6 +125,10 @@ 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,
+	FAULT_INFO,
+#endif
 };
 
 struct f2fs_attr {
@@ -140,6 +150,10 @@ 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)
+		return (unsigned char *)&f2fs_fault;
+#endif
 	return NULL;
 }
 
@@ -189,6 +203,10 @@ 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 && t > 1)
+		return -EINVAL;
+#endif
 	*ui = t;
 	return count;
 }
@@ -254,6 +272,15 @@ 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, f2fs_fault_info, inject_kmalloc, inject_kmalloc);
+F2FS_RW_ATTR(FAULT_INFO, f2fs_fault_info, inject_page_alloc, inject_page_alloc);
+F2FS_RW_ATTR(FAULT_INFO, f2fs_fault_info, inject_nid_alloc, inject_nid_alloc);
+F2FS_RW_ATTR(FAULT_INFO, f2fs_fault_info, inject_orphan, inject_orphan);
+F2FS_RW_ATTR(FAULT_INFO, f2fs_fault_info, inject_block, inject_block);
+F2FS_RW_ATTR(FAULT_INFO, f2fs_fault_info, inject_dir_depth, inject_dir_depth);
+#endif
 F2FS_GENERAL_RO_ATTR(lifetime_write_kbytes);
 
 #define ATTR_LIST(name) (&f2fs_attr_##name.attr)
@@ -290,6 +317,27 @@ 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_kmalloc),
+	ATTR_LIST(inject_page_alloc),
+	ATTR_LIST(inject_nid_alloc),
+	ATTR_LIST(inject_orphan),
+	ATTR_LIST(inject_block),
+	ATTR_LIST(inject_dir_depth),
+	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;
@@ -1798,6 +1846,16 @@ 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();
+	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;
@@ -1816,6 +1874,10 @@ 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();
@@ -1842,6 +1904,9 @@ 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();
 }
-- 
2.7.1


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