From 28f855b2e34ff38516493612c74bc02def4cfdda Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Thu, 17 Aug 2023 17:13:33 +0300 Subject: [PATCH 2/4] fs: create kiocb_{start,end}_write() helpers Commit ed0360bbab72b829437b67ebb2f9cfac19f59dfe upstream. aio, io_uring, cachefiles and overlayfs, all open code an ugly variant of file_{start,end}_write() to silence lockdep warnings. Create helpers for this lockdep dance so we can use the helpers in all the callers. Suggested-by: Jan Kara Signed-off-by: Amir Goldstein Reviewed-by: Jan Kara Reviewed-by: Jens Axboe Message-Id: <20230817141337.1025891-4-amir73il@gmail.com> Signed-off-by: Christian Brauner --- include/linux/fs.h | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/include/linux/fs.h b/include/linux/fs.h index a7d839b19606..4e475ded5cf5 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1797,6 +1797,41 @@ static inline bool sb_start_intwrite_trylock(struct super_block *sb) return __sb_start_write_trylock(sb, SB_FREEZE_FS); } +/** + * kiocb_start_write - get write access to a superblock for async file io + * @iocb: the io context we want to submit the write with + * + * This is a variant of sb_start_write() for async io submission. + * Should be matched with a call to kiocb_end_write(). + */ +static inline void kiocb_start_write(struct kiocb *iocb) +{ + struct inode *inode = file_inode(iocb->ki_filp); + + sb_start_write(inode->i_sb); + /* + * Fool lockdep by telling it the lock got released so that it + * doesn't complain about the held lock when we return to userspace. + */ + __sb_writers_release(inode->i_sb, SB_FREEZE_WRITE); +} + +/** + * kiocb_end_write - drop write access to a superblock after async file io + * @iocb: the io context we sumbitted the write with + * + * Should be matched with a call to kiocb_start_write(). + */ +static inline void kiocb_end_write(struct kiocb *iocb) +{ + struct inode *inode = file_inode(iocb->ki_filp); + + /* + * Tell lockdep we inherited freeze protection from submission thread. + */ + __sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE); + sb_end_write(inode->i_sb); +} extern bool inode_owner_or_capable(const struct inode *inode); -- 2.45.2