f2fs, lockdep: annotate mutex_lock_all() (bfe35965) · Commits · 戴 / test

Majianpeng reported a lockdep splat for f2fs. It turns out mutex_lock_all() acquires an array of locks (in global/local lock style). Any such operation is always serialized using cp_mutex, therefore there is no fs_lock[] lock-order issue; tell lockdep about this using the mutex_lock_nest_lock() primitive. Reported-by:

majianpeng <majianpeng@gmail.com> Signed-off-by:

Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by:

Jaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/f2fs.h

+11 −3

Original line number	Diff line number	Diff line
		@@ -495,9 +495,17 @@ static inline void clear_ckpt_flags(struct f2fs_checkpoint *cp, unsigned int f)

		static inline void mutex_lock_all(struct f2fs_sb_info *sbi)
		{
		int i = 0;
		for (; i < NR_GLOBAL_LOCKS; i++)
		mutex_lock(&sbi->fs_lock[i]);
		int i;

		for (i = 0; i < NR_GLOBAL_LOCKS; i++) {
		/*
		* This is the only time we take multiple fs_lock[]
		* instances; the order is immaterial since we
		* always hold cp_mutex, which serializes multiple
		* such operations.
		*/
		mutex_lock_nest_lock(&sbi->fs_lock[i], &sbi->cp_mutex);
		}
		}

		static inline void mutex_unlock_all(struct f2fs_sb_info *sbi)

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