[Tux3] Patch: Basic SMP locking for xcache

[OGAWA Hirofumi]

> -static struct xattr *xcache_lookup(struct xcache *xcache, unsigned atom, int *err)
> +static struct xattr *xcache_lookup(struct xcache *xcache, unsigned atom)
>  {
>  	if (!xcache)
>  		return NULL;

Maybe, return ERR_PTR(-ENOATTR); or something?

> @@ -356,46 +353,53 @@ static int xcache_update(struct inode *i
>  
>  struct xattr *get_xattr(struct inode *inode, char *name, unsigned len)
>  {
> -	int err = 0;
> -	atom_t atom = find_atom(tux_sb(inode->i_sb)->atable, name, len);
> +	struct inode *atable = tux_sb(inode->i_sb)->atable;
> +	mutex_lock(&atable->i_mutex);
> +	atom_t atom = find_atom(atable, name, len);
>  	if (atom == -1)
> -		return NULL;
> -	return xcache_lookup(tux_inode(inode)->xcache, atom, &err); // and what about the err???

mutex_unlock()

> +		return ERR_PTR(-ENOATTR);
> +	struct xattr *got = xcache_lookup(tux_inode(inode)->xcache, atom);
> +	mutex_unlock(&atable->i_mutex);
> +	return got;
>  }

tux3.c:200, tux3fuse.c:566, and tux3_getxattr:595 are needed to update
to check IS_ERR();

>  int set_xattr(struct inode *inode, char *name, unsigned len, void *data, unsigned size, unsigned flags)
>  {
> -	atom_t atom = make_atom(tux_sb(inode->i_sb)->atable, name, len);
> +	struct inode *atable = tux_sb(inode->i_sb)->atable;
> +	mutex_lock(&atable->i_mutex);
> +	atom_t atom = make_atom(atable, name, len);
>  	if (atom == -1)

mutex_unlock()

>  		return -EINVAL;

> -/* unused */
>  int del_xattr(struct inode *inode, char *name, unsigned len)
>  {
>  	int err = 0;
> -	atom_t atom = find_atom(tux_sb(inode->i_sb)->atable, name, len);
> +	struct inode *atable = tux_sb(inode->i_sb)->atable;
> +	mutex_lock(&atable->i_mutex);
> +	atom_t atom = find_atom(atable, name, len);
>  	if (atom == -1)

mutex_unlock()

>  		return -ENOATTR;
>  	struct xcache *xcache = tux_inode(inode)->xcache;
> -	struct xattr *xattr = xcache_lookup(xcache, atom, &err);
> -	if (err)
> -		return err;
> -	if (!xattr)
> -		return -ENOATTR;
> +	struct xattr *xattr = xcache_lookup(xcache, atom);
> +	if (IS_ERR(xattr))

mutex_unlock()

> +		return PTR_ERR(xattr);
>  	int used = remove_old(xcache, xattr);
>  	if (used)
> -		use_atom(tux_sb(inode->i_sb)->atable, atom, -used);
> +		use_atom(atable, atom, -used);
> +	mutex_unlock(&atable->i_mutex);
>  	return err;
>  }

Thanks.
-- 
OGAWA Hirofumi <hirofumi at mail.parknet.co.jp>

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