Commit 4363834d authored by Zizhi Wo's avatar Zizhi Wo Committed by Baokun Li
Browse files

fscache/cachefiles: add a memory barrier for page_write 

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IB5UKT



--------------------------------

In some functions with wake_up_bit(&cookie->flags, 0), the wake_up depends
on removing the cookie from the radix tree, but there is no memory barrier
between them.

Fix this issue by adding the memory barrier.

Fixes: 201a1542 ("FS-Cache: Handle pages pending storage that get evicted under OOM conditions")
Signed-off-by: default avatarZizhi Wo <wozizhi@huawei.com>
Signed-off-by: default avatarBaokun Li <libaokun1@huawei.com>
parent 8cfd33ca

fs/fscache/page.c

+6 −0
Original line number Diff line number Diff line
@@ -113,6 +113,8 @@ bool __fscache_maybe_release_page(struct fscache_cookie *cookie, 
		fscache_stat(&fscache_n_store_vmscan_gone);

	}



	/* Make sure the delete operation is performed before waking. */

	smp_mb();

	wake_up_bit(&cookie->flags, 0);

	trace_fscache_wake_cookie(cookie);

	if (xpage)
@@ -171,6 +173,8 @@ static void fscache_end_page_write(struct fscache_object *object, 
			trace_fscache_page(cookie, page, fscache_page_write_end_pend);

		}

		spin_unlock(&cookie->stores_lock);

		/* Make sure the delete operation is performed before waking. */

		smp_mb();

		wake_up_bit(&cookie->flags, 0);

		trace_fscache_wake_cookie(cookie);

	} else {
@@ -988,6 +992,8 @@ void fscache_invalidate_writes(struct fscache_cookie *cookie) 
			put_page(results[i]);

	}



	/* Make sure the delete operation is performed before waking. */

	smp_mb();

	wake_up_bit(&cookie->flags, 0);

	trace_fscache_wake_cookie(cookie);