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commit 1dbd449c9943e3145148cc893c2461b72ba6fef0
parent 1c0490ce902206f4685f812fa81304fd1adf4e35
Author: Waiman Long <longman@redhat.com>
Date:   Wed, 30 Jan 2019 13:52:36 -0500

fs/dcache: Fix incorrect nr_dentry_unused accounting in shrink_dcache_sb()

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>

Diffstat:
Mfs/dcache.c | 6+-----
1 file changed, 1 insertion(+), 5 deletions(-)

diff --git 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); }