f2fs: introduce FAULT_LOCK_TIMEOUT

This patch introduce a new fault type FAULT_LOCK_TIMEOUT, it can
be used to inject timeout into lock duration.

Timeout type can be set via /sys/fs/f2fs/<disk>/inject_timeout_type

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Author: chaseyu

Documentation/ABI/testing/sysfs-fs-f2fs

@@ -743,6 +743,7 @@ Description:	Support configuring fault injection type, should be
 		FAULT_INCONSISTENT_FOOTER        0x00200000
 		FAULT_ATOMIC_TIMEOUT             0x00400000 (1000ms)
 		FAULT_VMALLOC                    0x00800000
+		FAULT_LOCK_TIMEOUT               0x01000000 (1000ms)
 		===========================      ==========
 
 What:		/sys/fs/f2fs/<disk>/discard_io_aware_gran

Documentation/filesystems/f2fs.rst

@@ -217,6 +217,7 @@ fault_type=%d		 Support configuring fault injection type, should be
 			     FAULT_INCONSISTENT_FOOTER        0x00200000
 			     FAULT_ATOMIC_TIMEOUT             0x00400000 (1000ms)
 			     FAULT_VMALLOC                    0x00800000
+			     FAULT_LOCK_TIMEOUT               0x01000000 (1000ms)
 			     ===========================      ==========
 mode=%s			 Control block allocation mode which supports "adaptive"
 			 and "lfs". In "lfs" mode, there should be no random

fs/f2fs/checkpoint.c

@@ -63,6 +63,9 @@ static inline void trace_lock_elapsed_time_end(struct f2fs_rwsem *sem,
 	if (!lc->lock_trace)
 		return;
 
+	if (time_to_inject(sem->sbi, FAULT_LOCK_TIMEOUT))
+		f2fs_io_schedule_timeout_killable(DEFAULT_FAULT_TIMEOUT);
+
 	get_lock_elapsed_time(&tts);
 
 	total_time = div_u64(tts.total_time - lc->ts.total_time, npm);

fs/f2fs/f2fs.h

@@ -65,6 +65,7 @@ enum {
 	FAULT_INCONSISTENT_FOOTER,
 	FAULT_ATOMIC_TIMEOUT,
 	FAULT_VMALLOC,
+	FAULT_LOCK_TIMEOUT,
 	FAULT_MAX,
 };
 

fs/f2fs/super.c

@@ -69,6 +69,7 @@ const char *f2fs_fault_name[FAULT_MAX] = {
 	[FAULT_INCONSISTENT_FOOTER]	= "inconsistent footer",
 	[FAULT_ATOMIC_TIMEOUT]		= "atomic timeout",
 	[FAULT_VMALLOC]			= "vmalloc",
+	[FAULT_LOCK_TIMEOUT]		= "lock timeout",
 };
 
 int f2fs_build_fault_attr(struct f2fs_sb_info *sbi, unsigned long rate,