5.15-stable review patch. If anyone has any objections, please let me know.
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From: Amir Goldstein amir73il@gmail.com
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 jack@suse.cz Signed-off-by: Amir Goldstein amir73il@gmail.com Reviewed-by: Jan Kara jack@suse.cz Reviewed-by: Jens Axboe axboe@kernel.dk Message-Id: 20230817141337.1025891-4-amir73il@gmail.com Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/fs.h | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+)
diff --git a/include/linux/fs.h b/include/linux/fs.h index 6ff6ade229a07..2ef0e48c89ec4 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3058,6 +3058,42 @@ static inline void file_end_write(struct file *file) __sb_end_write(file_inode(file)->i_sb, SB_FREEZE_WRITE); }
+/** + * 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); +} + /* * This is used for regular files where some users -- especially the * currently executed binary in a process, previously handled via