From 1dbd449c9943e3145148cc893c2461b72ba6fef0 Mon Sep 17 00:00:00 2001
From: Waiman Long <longman@redhat.com>
Date: Wed Jan 30 13:52:36 2019 -0500
Subject: [PATCH] fs/dcache: Fix incorrect nr_dentry_unused accounting in shrink_dcache_sb()
Git-commit: 1dbd449c9943e3145148cc893c2461b72ba6fef0
References: git-fixes
Patch-mainline: v5.0-rc5
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@kernel.org
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
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);
}