Re: [patch 37/61] lock validator: special locking: dcache

[Andrew Morton]

On Mon, 29 May 2006 23:26:08 +0200
Ingo Molnar <mingo@xxxxxxx> wrote:

> From: Ingo Molnar <mingo@xxxxxxx>
> 
> teach special (recursive) locking code to the lock validator. Has no
> effect on non-lockdep kernels.
> 
> Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
> Signed-off-by: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
> ---
>  fs/dcache.c            |    6 +++---
>  include/linux/dcache.h |   12 ++++++++++++
>  2 files changed, 15 insertions(+), 3 deletions(-)
> 
> Index: linux/fs/dcache.c
> ===================================================================
> --- linux.orig/fs/dcache.c
> +++ linux/fs/dcache.c
> @@ -1380,10 +1380,10 @@ void d_move(struct dentry * dentry, stru
>  	 */
>  	if (target < dentry) {
>  		spin_lock(&target->d_lock);
> -		spin_lock(&dentry->d_lock);
> +		spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
>  	} else {
>  		spin_lock(&dentry->d_lock);
> -		spin_lock(&target->d_lock);
> +		spin_lock_nested(&target->d_lock, DENTRY_D_LOCK_NESTED);
>  	}
>  
>  	/* Move the dentry to the target hash queue, if on different bucket */
> @@ -1420,7 +1420,7 @@ already_unhashed:
>  	}
>  
>  	list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs);
> -	spin_unlock(&target->d_lock);
> +	spin_unlock_non_nested(&target->d_lock);
>  	fsnotify_d_move(dentry);
>  	spin_unlock(&dentry->d_lock);
>  	write_sequnlock(&rename_lock);
> Index: linux/include/linux/dcache.h
> ===================================================================
> --- linux.orig/include/linux/dcache.h
> +++ linux/include/linux/dcache.h
> @@ -114,6 +114,18 @@ struct dentry {
>  	unsigned char d_iname[DNAME_INLINE_LEN_MIN];	/* small names */
>  };
>  
> +/*
> + * dentry->d_lock spinlock nesting types:
> + *
> + * 0: normal
> + * 1: nested
> + */
> +enum dentry_d_lock_type
> +{
> +	DENTRY_D_LOCK_NORMAL,
> +	DENTRY_D_LOCK_NESTED
> +};
> +
>  struct dentry_operations {
>  	int (*d_revalidate)(struct dentry *, struct nameidata *);
>  	int (*d_hash) (struct dentry *, struct qstr *);

DENTRY_D_LOCK_NORMAL isn't used anywhere.

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