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Commit b8c502b8 authored by Chao Yu's avatar Chao Yu Committed by Jaegeuk Kim
Browse files

f2fs: fix potential overflow when adjusting GC cycle 



While comparing signed and unsigned variables, compiler will converts the
signed value to unsigned one, due to this reason, {in,de}crease_sleep_time
may return overflowed result.

Signed-off-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 9a20d391

fs/f2fs/gc.c

+1 −1
Original line number Diff line number Diff line
@@ -28,7 +28,7 @@ static int gc_thread_func(void *data) 
	struct f2fs_sb_info *sbi = data;

	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;

	wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;

	long wait_ms;

	unsigned int wait_ms;



	wait_ms = gc_th->min_sleep_time;

fs/f2fs/gc.h

+15 −8
Original line number Diff line number Diff line
@@ -69,25 +69,32 @@ static inline block_t limit_free_user_blocks(struct f2fs_sb_info *sbi) 
}



static inline void increase_sleep_time(struct f2fs_gc_kthread *gc_th,

								long *wait)

							unsigned int *wait)

{

	unsigned int min_time = gc_th->min_sleep_time;

	unsigned int max_time = gc_th->max_sleep_time;



	if (*wait == gc_th->no_gc_sleep_time)

		return;



	*wait += gc_th->min_sleep_time;

	if (*wait > gc_th->max_sleep_time)

		*wait = gc_th->max_sleep_time;

	if ((long long)*wait + (long long)min_time > (long long)max_time)

		*wait = max_time;

	else

		*wait += min_time;

}



static inline void decrease_sleep_time(struct f2fs_gc_kthread *gc_th,

								long *wait)

							unsigned int *wait)

{

	unsigned int min_time = gc_th->min_sleep_time;



	if (*wait == gc_th->no_gc_sleep_time)

		*wait = gc_th->max_sleep_time;



	*wait -= gc_th->min_sleep_time;

	if (*wait <= gc_th->min_sleep_time)

		*wait = gc_th->min_sleep_time;

	if ((long long)*wait - (long long)min_time < (long long)min_time)

		*wait = min_time;

	else

		*wait -= min_time;

}



static inline bool has_enough_invalid_blocks(struct f2fs_sb_info *sbi)

include/trace/events/f2fs.h

+3 −3
Original line number Diff line number Diff line
@@ -543,14 +543,14 @@ TRACE_EVENT(f2fs_map_blocks, 


TRACE_EVENT(f2fs_background_gc,



	TP_PROTO(struct super_block *sb, long wait_ms,

	TP_PROTO(struct super_block *sb, unsigned int wait_ms,

			unsigned int prefree, unsigned int free),



	TP_ARGS(sb, wait_ms, prefree, free),



	TP_STRUCT__entry(

		__field(dev_t,	dev)

		__field(long,	wait_ms)

		__field(unsigned int,	wait_ms)

		__field(unsigned int,	prefree)

		__field(unsigned int,	free)

	),
@@ -562,7 +562,7 @@ TRACE_EVENT(f2fs_background_gc, 
		__entry->free		= free;

	),



	TP_printk("dev = (%d,%d), wait_ms = %ld, prefree = %u, free = %u",

	TP_printk("dev = (%d,%d), wait_ms = %u, prefree = %u, free = %u",

		show_dev(__entry->dev),

		__entry->wait_ms,

		__entry->prefree,