Re: [PATCH v2] erofs: protect s_inodes with s_inode_list_lock

[JeffleXu <jefflexu@linux.alibaba.com>]

On 10/17/22 9:55 AM, Dawei Li wrote:
> s_inodes is superblock-specific resource, which should be
> protected by sb's specific lock s_inode_list_lock.
> 
> v2: update the locking mechanisim to protect mutual-exclusive access
> both for s_inode_list_lock & erofs_fscache_domain_init_cookie(), as the
> reviewing comments from Jia Zhu.
> 
> v1: https://lore.kernel.org/all/TYCP286MB23237A9993E0FFCFE5C2BDBECA269@TYCP286MB2323.JPNP286.PROD.OUTLOOK.COM/
> 
> base-commit: 8436c4a57bd147b0bd2943ab499bb8368981b9e1
> 
> Signed-off-by: Dawei Li <set_pte_at@outlook.com>

Fixes: 7d41963759fe ("erofs: Support sharing cookies in the same domain")

LGTM.

Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>

> ---
>  fs/erofs/fscache.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
> index 998cd26a1b3b..fe05bc51f9f2 100644
> --- a/fs/erofs/fscache.c
> +++ b/fs/erofs/fscache.c
> @@ -590,14 +590,17 @@ struct erofs_fscache *erofs_domain_register_cookie(struct super_block *sb,
>  	struct super_block *psb = erofs_pseudo_mnt->mnt_sb;
>  
>  	mutex_lock(&erofs_domain_cookies_lock);
> +	spin_lock(&psb->s_inode_list_lock);
>  	list_for_each_entry(inode, &psb->s_inodes, i_sb_list) {
>  		ctx = inode->i_private;
>  		if (!ctx || ctx->domain != domain || strcmp(ctx->name, name))
>  			continue;
>  		igrab(inode);
> +		spin_unlock(&psb->s_inode_list_lock);
>  		mutex_unlock(&erofs_domain_cookies_lock);
>  		return ctx;
>  	}
> +	spin_unlock(&psb->s_inode_list_lock);
>  	ctx = erofs_fscache_domain_init_cookie(sb, name, need_inode);
>  	mutex_unlock(&erofs_domain_cookies_lock);
>  	return ctx;

-- 
Thanks,
Jingbo