Commit 8cfd33ca authored by Zizhi Wo's avatar Zizhi Wo Committed by Baokun Li
Browse files

fscache/cachefiles: add a memory barrier for waking and waiting 

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



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

This patch modifies some functions, adds barriers in fscache/cachefiles to
both wake and wait processes that may be problematic due to out-of-order
memory.

Fixes: ef778e7a ("FS-Cache: Provide proper invalidation")
Fixes: da9803bc ("FS-Cache: Add interface to check consistency of a cached object")
Fixes: 94d30ae9 ("FS-Cache: Provide the ability to enable/disable cookies")
Fixes: b73608d715eb ("fscache: add a waiting mechanism when duplicate cookies are detected")
Signed-off-by: default avatarZizhi Wo <wozizhi@huawei.com>
Signed-off-by: default avatarBaokun Li <libaokun1@huawei.com>
parent e7213ad6

fs/cachefiles/namei.c

+1 −3
Original line number Diff line number Diff line
@@ -264,11 +264,9 @@ void cachefiles_mark_object_inactive(struct cachefiles_cache *cache, 


	write_lock(&cache->active_lock);

	rb_erase(&object->active_node, &cache->active_nodes);

	clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags);

	clear_and_wake_up_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags);

	write_unlock(&cache->active_lock);



	wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE);



	/* This object can now be culled, so we need to let the daemon know

	 * that there is something it can remove if it needs to.

	 */

fs/fscache/cookie.c

+7 −9
Original line number Diff line number Diff line
@@ -223,13 +223,13 @@ static int fscache_wait_on_cookie_collision(struct fscache_cookie *candidate) 
{

	int ret;



	ret = wait_on_bit_timeout(&candidate->flags, FSCACHE_COOKIE_ACQUIRE_PENDING,

	ret = wait_on_bit_timeout_acquire(&candidate->flags, FSCACHE_COOKIE_ACQUIRE_PENDING,

					  TASK_INTERRUPTIBLE, 20 * HZ);

	if (ret == -EINTR)

		return ret;

	if (fscache_is_acquire_pending(candidate)) {

		pr_notice("Potential cookie collision!");

		return wait_on_bit(&candidate->flags, FSCACHE_COOKIE_ACQUIRE_PENDING,

		return wait_on_bit_acquire(&candidate->flags, FSCACHE_COOKIE_ACQUIRE_PENDING,

					   TASK_INTERRUPTIBLE);

	}

	return 0;
@@ -445,8 +445,7 @@ void __fscache_enable_cookie(struct fscache_cookie *cookie, 
	}



out_unlock:

	clear_bit_unlock(FSCACHE_COOKIE_ENABLEMENT_LOCK, &cookie->flags);

	wake_up_bit(&cookie->flags, FSCACHE_COOKIE_ENABLEMENT_LOCK);

	clear_and_wake_up_bit(FSCACHE_COOKIE_ENABLEMENT_LOCK, &cookie->flags);

}

EXPORT_SYMBOL(__fscache_enable_cookie);
@@ -725,7 +724,7 @@ void __fscache_wait_on_invalidate(struct fscache_cookie *cookie) 
{

	_enter("%p", cookie);



	wait_on_bit(&cookie->flags, FSCACHE_COOKIE_INVALIDATING,

	wait_on_bit_acquire(&cookie->flags, FSCACHE_COOKIE_INVALIDATING,

		    TASK_UNINTERRUPTIBLE);



	_leave("");
@@ -842,8 +841,7 @@ void __fscache_disable_cookie(struct fscache_cookie *cookie, 
	}



out_unlock_enable:

	clear_bit_unlock(FSCACHE_COOKIE_ENABLEMENT_LOCK, &cookie->flags);

	wake_up_bit(&cookie->flags, FSCACHE_COOKIE_ENABLEMENT_LOCK);

	clear_and_wake_up_bit(FSCACHE_COOKIE_ENABLEMENT_LOCK, &cookie->flags);

	_leave("");

}

EXPORT_SYMBOL(__fscache_disable_cookie);

fs/fscache/page.c

+4 −4
Original line number Diff line number Diff line
@@ -383,7 +383,7 @@ int fscache_wait_for_operation_activation(struct fscache_object *object, 
	_debug(">>> WT");

	if (stat_op_waits)

		fscache_stat(stat_op_waits);

	if (wait_on_bit(&op->flags, FSCACHE_OP_WAITING,

	if (wait_on_bit_acquire(&op->flags, FSCACHE_OP_WAITING,

				TASK_INTERRUPTIBLE) != 0) {

		trace_fscache_op(object->cookie, op, fscache_op_signal);

		ret = fscache_cancel_op(op, false);
@@ -392,7 +392,7 @@ int fscache_wait_for_operation_activation(struct fscache_object *object, 


		/* it's been removed from the pending queue by another party,

		 * so we should get to run shortly */

		wait_on_bit(&op->flags, FSCACHE_OP_WAITING,

		wait_on_bit_acquire(&op->flags, FSCACHE_OP_WAITING,

				    TASK_UNINTERRUPTIBLE);

	}

	_debug("<<< GO");