erofs: protect s_inodes with s_inode_list_lock for fscache

s_inodes is superblock-specific resource, which should be
protected by sb's specific lock s_inode_list_lock.

Link: https://lore.kernel.org/r/TYCP286MB23238380DE3B74874E8D78ABCA299@TYCP286MB2323.JPNP286.PROD.OUTLOOK.COM
Fixes: 7d41963759fe ("erofs: Support sharing cookies in the same domain")
Reviewed-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Jia Zhu <zhujia.zj@bytedance.com>
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Signed-off-by: Dawei Li <set_pte_at@outlook.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
index 998cd26a1b3b113106e6ba9c0aef898b29342750..fe05bc51f9f2f3f26f8de0272d99eb56c67cf96a 100644 (file)
--- 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;