* [PATCH v4 1/3] fs/dcache: Fix incorrect nr_dentry_unused accounting in shrink_dcache_sb()
[not found] <1536773742-32687-1-git-send-email-longman@redhat.com>
@ 2018-09-12 17:35 ` Waiman Long
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From: Waiman Long @ 2018-09-12 17:35 UTC (permalink / raw)
To: Alexander Viro, Jonathan Corbet, Andrew Morton
Cc: linux-kernel, linux-fsdevel, linux-mm, linux-doc,
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
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 <longman@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---
fs/dcache.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index 2e7e8d8..cb515f1 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1202,15 +1202,11 @@ 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
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