From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt1-f200.google.com (mail-qt1-f200.google.com [209.85.160.200]) by kanga.kvack.org (Postfix) with ESMTP id F1B7E8E01DC for ; Fri, 14 Dec 2018 16:53:21 -0500 (EST) Received: by mail-qt1-f200.google.com with SMTP id z6so6891510qtj.21 for ; Fri, 14 Dec 2018 13:53:21 -0800 (PST) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id t64si3253694qkf.154.2018.12.14.13.53.21 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 14 Dec 2018 13:53:21 -0800 (PST) From: Waiman Long Subject: [RESEND PATCH v4 1/3] fs/dcache: Fix incorrect nr_dentry_unused accounting in shrink_dcache_sb() Date: Fri, 14 Dec 2018 16:53:02 -0500 Message-Id: <1544824384-17668-2-git-send-email-longman@redhat.com> In-Reply-To: <1544824384-17668-1-git-send-email-longman@redhat.com> References: <1544824384-17668-1-git-send-email-longman@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Alexander Viro , Jonathan Corbet , Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, "Luis R. Rodriguez" , Kees Cook , Linus Torvalds , Jan Kara , "Paul E. McKenney" , Ingo Molnar , Miklos Szeredi , Matthew Wilcox , Larry Woodman , James Bottomley , "Wangkai (Kevin C)" , Michal Hocko , Waiman Long , stable@vger.kernel.org The nr_dentry_unused per-cpu counter tracks dentries in both the LRU lists and the shrink lists where the DCACHE_LRU_LIST bit is set. The shrink_dcache_sb() function moves dentries from the LRU list to a shrink list and subtracts the dentry count from nr_dentry_unused. This is incorrect as the nr_dentry_unused count Will also be decremented in shrink_dentry_list() via d_shrink_del(). To fix this double decrement, the decrement in the shrink_dcache_sb() function is taken out. Fixes: 4e717f5c1083 ("list_lru: remove special case function list_lru_dispose_all." Cc: stable@vger.kernel.org Signed-off-by: Waiman Long Reviewed-by: Dave Chinner --- fs/dcache.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/fs/dcache.c b/fs/dcache.c index 2593153..44e5652 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1188,15 +1188,11 @@ static enum lru_status dentry_lru_isolate_shrink(struct list_head *item, */ void shrink_dcache_sb(struct super_block *sb) { - long freed; - do { LIST_HEAD(dispose); - freed = list_lru_walk(&sb->s_dentry_lru, + list_lru_walk(&sb->s_dentry_lru, dentry_lru_isolate_shrink, &dispose, 1024); - - this_cpu_sub(nr_dentry_unused, freed); shrink_dentry_list(&dispose); } while (list_lru_count(&sb->s_dentry_lru) > 0); } -- 1.8.3.1