On Tue 24-01-23 14:30:18, Jeff Layton wrote:
> Reviewed-by: NeilBrown <neilb@xxxxxxx>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
Reasonable. Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> fs/libfs.c | 36 ++++++++++++++++++++++++++++++++++++
> include/linux/iversion.h | 38 ++------------------------------------
> 2 files changed, 38 insertions(+), 36 deletions(-)
>
> diff --git a/fs/libfs.c b/fs/libfs.c
> index aada4e7c8713..17ecc47696e1 100644
> --- a/fs/libfs.c
> +++ b/fs/libfs.c
> @@ -1582,3 +1582,39 @@ bool inode_maybe_inc_iversion(struct inode *inode, bool force)
> return true;
> }
> EXPORT_SYMBOL(inode_maybe_inc_iversion);
> +
> +/**
> + * inode_query_iversion - read i_version for later use
> + * @inode: inode from which i_version should be read
> + *
> + * Read the inode i_version counter. This should be used by callers that wish
> + * to store the returned i_version for later comparison. This will guarantee
> + * that a later query of the i_version will result in a different value if
> + * anything has changed.
> + *
> + * In this implementation, we fetch the current value, set the QUERIED flag and
> + * then try to swap it into place with a cmpxchg, if it wasn't already set. If
> + * that fails, we try again with the newly fetched value from the cmpxchg.
> + */
> +u64 inode_query_iversion(struct inode *inode)
> +{
> + u64 cur, new;
> +
> + cur = inode_peek_iversion_raw(inode);
> + do {
> + /* If flag is already set, then no need to swap */
> + if (cur & I_VERSION_QUERIED) {
> + /*
> + * This barrier (and the implicit barrier in the
> + * cmpxchg below) pairs with the barrier in
> + * inode_maybe_inc_iversion().
> + */
> + smp_mb();
> + break;
> + }
> +
> + new = cur | I_VERSION_QUERIED;
> + } while (!atomic64_try_cmpxchg(&inode->i_version, &cur, new));
> + return cur >> I_VERSION_QUERIED_SHIFT;
> +}
> +EXPORT_SYMBOL(inode_query_iversion);
> diff --git a/include/linux/iversion.h b/include/linux/iversion.h
> index e27bd4f55d84..6755d8b4f20b 100644
> --- a/include/linux/iversion.h
> +++ b/include/linux/iversion.h
> @@ -234,42 +234,6 @@ inode_peek_iversion(const struct inode *inode)
> return inode_peek_iversion_raw(inode) >> I_VERSION_QUERIED_SHIFT;
> }
>
> -/**
> - * inode_query_iversion - read i_version for later use
> - * @inode: inode from which i_version should be read
> - *
> - * Read the inode i_version counter. This should be used by callers that wish
> - * to store the returned i_version for later comparison. This will guarantee
> - * that a later query of the i_version will result in a different value if
> - * anything has changed.
> - *
> - * In this implementation, we fetch the current value, set the QUERIED flag and
> - * then try to swap it into place with a cmpxchg, if it wasn't already set. If
> - * that fails, we try again with the newly fetched value from the cmpxchg.
> - */
> -static inline u64
> -inode_query_iversion(struct inode *inode)
> -{
> - u64 cur, new;
> -
> - cur = inode_peek_iversion_raw(inode);
> - do {
> - /* If flag is already set, then no need to swap */
> - if (cur & I_VERSION_QUERIED) {
> - /*
> - * This barrier (and the implicit barrier in the
> - * cmpxchg below) pairs with the barrier in
> - * inode_maybe_inc_iversion().
> - */
> - smp_mb();
> - break;
> - }
> -
> - new = cur | I_VERSION_QUERIED;
> - } while (!atomic64_try_cmpxchg(&inode->i_version, &cur, new));
> - return cur >> I_VERSION_QUERIED_SHIFT;
> -}
> -
> /*
> * For filesystems without any sort of change attribute, the best we can
> * do is fake one up from the ctime:
> @@ -283,6 +247,8 @@ static inline u64 time_to_chattr(struct timespec64 *t)
> return chattr;
> }
>
> +u64 inode_query_iversion(struct inode *inode);
> +
> /**
> * inode_eq_iversion_raw - check whether the raw i_version counter has changed
> * @inode: inode to check
> --
> 2.39.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
