Re: [PATCH 2/2] dcache: use lockref routines for dead count checks

[Jan Kara]

On Fri 24-07-26 19:14:22, Mateusz Guzik wrote:
> Signed-off-by: Mateusz Guzik <mjguzik@xxxxxxxxx>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@xxxxxxx>

								Honza

> ---
>  fs/dcache.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/dcache.c b/fs/dcache.c
> index 3e9af9de7074..2aee85f3fbaa 100644
> --- a/fs/dcache.c
> +++ b/fs/dcache.c
> @@ -434,7 +434,7 @@ static inline void __d_clear_type_and_inode(struct dentry *dentry)
>  static void dentry_free(struct dentry *dentry)
>  {
>  	DENTRY_WARN_ONCE(d_really_is_positive(dentry), dentry);
> -	DENTRY_WARN_ONCE(dentry->d_lockref.count >= 0, dentry);
> +	DENTRY_WARN_ONCE(!lockref_is_dead(&dentry->d_lockref), dentry);
>  	D_FLAG_VERIFY(dentry, 0);
>  	if (unlikely(dname_external(dentry))) {
>  		struct external_name *p = external_name(dentry);
> @@ -782,7 +782,7 @@ static bool lock_for_kill(struct dentry *dentry)
>   *
>   * If @dentry is idle and remains such after we assemble the full
>   * locking environment for eviction (see lock_for_kill() for details)
> - * we mark it doomed (->d_lockref.count < 0) and proceed to detaching
> + * we mark it doomed (see lockref_mark_dead()) and proceed to detaching
>   * it from any filesystem objects.  Otherwise we drop ->d_lock and
>   * return %NULL.
>   *
> @@ -946,7 +946,7 @@ static inline bool fast_dput(struct dentry *dentry)
>  	if (unlikely(ret < 0)) {
>  		spin_lock(&dentry->d_lock);
>  		rcu_read_unlock();
> -		if (WARN_ON_ONCE(dentry->d_lockref.count <= 0)) {
> +		if (WARN_ON_ONCE(lockref_is_dead_or_zero(&dentry->d_lockref))) {
>  			spin_unlock(&dentry->d_lock);
>  			return true;
>  		}
> @@ -1644,7 +1644,7 @@ static enum d_walk_ret select_collect(void *_data, struct dentry *dentry)
>  	if (data->start == dentry)
>  		goto out;
>  
> -	if (dentry->d_lockref.count <= 0) {
> +	if (lockref_is_dead_or_zero(&dentry->d_lockref)) {
>  		__move_to_shrink_list(dentry, &data->dispose);
>  		data->found++;
>  	}
> @@ -1676,7 +1676,7 @@ static enum d_walk_ret select_collect2(void *_data, struct dentry *dentry)
>  	if (data->start == dentry)
>  		goto out;
>  
> -	if (dentry->d_lockref.count <= 0) {
> +	if (lockref_is_dead_or_zero(&dentry->d_lockref)) {
>  		if (!__move_to_shrink_list(dentry, &data->dispose)) {
>  			/*
>  			 * We need an enter RCU read-side critical area that
> @@ -1747,7 +1747,7 @@ static void shrink_dcache_tree(struct dentry *parent, bool for_umount)
>  			spin_lock(&v->d_lock);
>  			rcu_read_unlock();
>  
> -			if (unlikely(v->d_lockref.count < 0)) {
> +			if (unlikely(lockref_is_dead(&v->d_lockref))) {
>  				// It's doomed; if it isn't dead yet, notify us
>  				// once it becomes invisible to d_walk().
>  				need_wait = d_add_waiter(v, &wait);
> @@ -1823,7 +1823,7 @@ void shrink_dcache_for_umount(struct super_block *sb)
>  		spin_unlock(&sb->s_roots_lock);
>  		spin_lock(&dentry->d_lock);
>  		rcu_read_unlock();
> -		if (unlikely(dentry->d_lockref.count < 0)) {
> +		if (unlikely(lockref_is_dead(&dentry->d_lockref))) {
>  			struct completion_list wait;
>  			bool need_wait = d_add_waiter(dentry, &wait);
>  
> @@ -2822,7 +2822,7 @@ struct dentry *d_alloc_parallel(struct dentry *parent,
>  		spin_lock(&dentry->d_lock);
>  		rcu_read_unlock();
>  		/* now we can try to grab a reference */
> -		if (unlikely(dentry->d_lockref.count < 0)) {
> +		if (unlikely(lockref_is_dead(&dentry->d_lockref))) {
>  			spin_unlock(&dentry->d_lock);
>  			goto retry;
>  		}
> -- 
> 2.48.1
> 
-- 
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR