f2fs: support fault_type mount option

Previously, once fault injection is on, by default, all kind of faults
will be injected to f2fs, if we want to trigger single or specified
combined type during the test, we need to configure sysfs entry, it will
be a little inconvenient to integrate sysfs configuring into testsuit,
such as xfstest.

So this patch introduces a new mount option 'fault_type' to assist old
option 'fault_injection', with these two mount options, we can specify
any fault rate/type at mount-time.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
index 69f8de9..e5edd29 100644
--- a/Documentation/filesystems/f2fs.txt
+++ b/Documentation/filesystems/f2fs.txt
@@ -157,6 +157,24 @@
                        persist data of regular and symlink.
 fault_injection=%d     Enable fault injection in all supported types with
                        specified injection rate.
+fault_type=%d          Support configuring fault injection type, should be
+                       enabled with fault_injection option, fault type value
+                       is shown below, it supports single or combined type.
+                       Type_Name		Type_Value
+                       FAULT_KMALLOC		0x000000001
+                       FAULT_KVMALLOC		0x000000002
+                       FAULT_PAGE_ALLOC		0x000000004
+                       FAULT_PAGE_GET		0x000000008
+                       FAULT_ALLOC_BIO		0x000000010
+                       FAULT_ALLOC_NID		0x000000020
+                       FAULT_ORPHAN		0x000000040
+                       FAULT_BLOCK		0x000000080
+                       FAULT_DIR_DEPTH		0x000000100
+                       FAULT_EVICT_INODE	0x000000200
+                       FAULT_TRUNCATE		0x000000400
+                       FAULT_IO			0x000000800
+                       FAULT_CHECKPOINT		0x000001000
+                       FAULT_DISCARD		0x000002000
 mode=%s                Control block allocation mode which supports "adaptive"
                        and "lfs". In "lfs" mode, there should be no random
                        writes towards main area.