Commit e31a6a9d authored by Waiman Long's avatar Waiman Long Committed by Greg Kroah-Hartman

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

commit 1dbd449c9943e3145148cc893c2461b72ba6fef0 upstream.

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: 4e717f5c ("list_lru: remove special case function list_lru_dispose_all."
Cc: stable@kernel.org
Signed-off-by: 's avatarWaiman Long <longman@redhat.com>
Reviewed-by: 's avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: 's avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 600c4bd1
......@@ -1155,15 +1155,11 @@ 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);
cond_resched();
} while (list_lru_count(&sb->s_dentry_lru) > 0);
......
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