On Thu, Nov 05, 2020 at 08:10:34PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> Break this function into two helpers so that it's obvious that the
> trylock versions return a value that must be checked, and the blocking
> versions don't require that. While we're at it, clean up the return
> type mismatch.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> fs/aio.c | 2 +-
> fs/io_uring.c | 3 +--
> fs/super.c | 18 ++++++++++++------
> include/linux/fs.h | 21 +++++++++++----------
> 4 files changed, 25 insertions(+), 19 deletions(-)
>
>
> diff --git a/fs/aio.c b/fs/aio.c
> index c45c20d87538..04bb4bac327f 100644
> --- a/fs/aio.c
> +++ b/fs/aio.c
> @@ -1572,7 +1572,7 @@ static int aio_write(struct kiocb *req, const struct iocb *iocb,
> * we return to userspace.
> */
> if (S_ISREG(file_inode(file)->i_mode)) {
> - __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, true);
> + __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE);
This should use sb_start_write()
> if (req->flags & REQ_F_ISREG) {
> - __sb_start_write(file_inode(req->file)->i_sb,
> - SB_FREEZE_WRITE, true);
> + __sb_start_write(file_inode(req->file)->i_sb, SB_FREEZE_WRITE);
Same.
> +void __sb_start_write(struct super_block *sb, int level)
> {
> + percpu_down_read(sb->s_writers.rw_sem + level - 1);
> }
> EXPORT_SYMBOL(__sb_start_write);
>
> +/*
> + * This is an internal function, please use sb_start_{write,pagefault,intwrite}
> + * instead.
> + */
> +bool __sb_start_write_trylock(struct super_block *sb, int level)
> +{
> + return percpu_down_read_trylock(sb->s_writers.rw_sem + level - 1);
> +}
> +EXPORT_SYMBOL_GPL(__sb_start_write_trylock);
I think these can be inline in the headers, or even be merged into
the few callers.
> @@ -2756,14 +2757,14 @@ static inline void file_start_write(struct file *file)
> {
> if (!S_ISREG(file_inode(file)->i_mode))
> return;
> - __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, true);
> + __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE);
This should use sb_start_write.
> }
>
> static inline bool file_start_write_trylock(struct file *file)
> {
> if (!S_ISREG(file_inode(file)->i_mode))
> return true;
> - return __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, false);
> + return __sb_start_write_trylock(file_inode(file)->i_sb, SB_FREEZE_WRITE);
And this one sb_start_write_trylock.
