From bfe35965ecdc6038314d03456b94d9ba451c289d Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 16 May 2013 20:03:12 +0200 Subject: f2fs, lockdep: annotate mutex_lock_all() 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 Signed-off-by: Peter Zijlstra Signed-off-by: Jaegeuk Kim --- fs/f2fs/f2fs.h | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) (limited to 'fs/f2fs') diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 9360a03fcc96..9182b2710db7 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -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) -- cgit v1.2.3-59-g8ed1b