On Wed, Mar 16, 2022 at 10:22:39PM +0900, Naohiro Aota wrote:
> Add a function sb_write_started() to return if sb_start_write() is
> properly called. It is used in the next commit.
>
> Also, add the similar functions for sb_start_pagefault() and
> sb_start_intwrite().
>
> Reviewed-by: Filipe Manana <fdmanana@xxxxxxxx>
> Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx>
> ---
> include/linux/fs.h | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 27746a3da8fd..0c8714d64169 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1732,6 +1732,11 @@ static inline bool __sb_start_write_trylock(struct super_block *sb, int level)
> #define __sb_writers_release(sb, lev) \
> percpu_rwsem_release(&(sb)->s_writers.rw_sem[(lev)-1], 1, _THIS_IP_)
>
> +static inline bool __sb_write_started(struct super_block *sb, int level)
> +{
> + return lockdep_is_held_type(sb->s_writers.rw_sem + level - 1, 1);
> +}
> +
> /**
> * sb_end_write - drop write access to a superblock
> * @sb: the super we wrote to
> @@ -1797,6 +1802,11 @@ static inline bool sb_start_write_trylock(struct super_block *sb)
> return __sb_start_write_trylock(sb, SB_FREEZE_WRITE);
> }
>
> +static inline bool sb_write_started(struct super_block *sb)
> +{
> + return __sb_write_started(sb, SB_FREEZE_WRITE);
> +}
> +
> /**
> * sb_start_pagefault - get write access to a superblock from a page fault
> * @sb: the super we write to
> @@ -1821,6 +1831,11 @@ static inline void sb_start_pagefault(struct super_block *sb)
> __sb_start_write(sb, SB_FREEZE_PAGEFAULT);
> }
>
> +static inline bool sb_pagefault_started(struct super_block *sb)
> +{
> + return __sb_write_started(sb, SB_FREEZE_PAGEFAULT);
> +}
> +
> /**
> * sb_start_intwrite - get write access to a superblock for internal fs purposes
> * @sb: the super we write to
> @@ -1844,6 +1859,11 @@ static inline bool sb_start_intwrite_trylock(struct super_block *sb)
> return __sb_start_write_trylock(sb, SB_FREEZE_FS);
> }
>
> +static inline bool sb_intwrite_started(struct super_block *sb)
> +{
> + return __sb_write_started(sb, SB_FREEZE_FS);
> +}
> +
> bool inode_owner_or_capable(struct user_namespace *mnt_userns,
> const struct inode *inode);
>
We should not be adding completely unused code to the VFS APIs.
Just rename __sb_write_started() to sb_write_started() and pass
SB_FREEZE_WRITE directly from the single debug assert that you've
added that needs this check.
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
