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From: libaokun@huaweicloud.com
To: netfs@lists.linux.dev, dhowells@redhat.com, jlayton@kernel.org
Cc: libaokun@huaweicloud.com, yangerkun@huawei.com,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	hsiangkao@linux.alibaba.com, linux-erofs@lists.ozlabs.org,
	yukuai3@huawei.com
Subject: [PATCH v2 12/12] cachefiles: make on-demand read killable
Date: Wed, 15 May 2024 16:46:01 +0800	[thread overview]
Message-ID: <20240515084601.3240503-13-libaokun@huaweicloud.com> (raw)
In-Reply-To: <20240515084601.3240503-1-libaokun@huaweicloud.com>

From: Baokun Li <libaokun1@huawei.com>

Replacing wait_for_completion() with wait_for_completion_killable() in
cachefiles_ondemand_send_req() allows us to kill processes that might
trigger a hunk_task if the daemon is abnormal.

But now only CACHEFILES_OP_READ is killable, because OP_CLOSE and OP_OPEN
is initiated from kworker context and the signal is prohibited in these
kworker.

Note that when the req in xas changes, i.e. xas_load(&xas) != req, it
means that a process will complete the current request soon, so wait
again for the request to be completed.

Suggested-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jia Zhu <zhujia.zj@bytedance.com>
---
 fs/cachefiles/ondemand.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c
index a511d0a89109..bdc2d6dbadce 100644
--- a/fs/cachefiles/ondemand.c
+++ b/fs/cachefiles/ondemand.c
@@ -544,8 +544,25 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object,
 		goto out;
 
 	wake_up_all(&cache->daemon_pollwq);
-	wait_for_completion(&req->done);
-	ret = req->error;
+wait:
+	ret = wait_for_completion_killable(&req->done);
+	if (!ret) {
+		ret = req->error;
+	} else {
+		xas_reset(&xas);
+		xas_lock(&xas);
+		if (xas_load(&xas) == req) {
+			xas_store(&xas, NULL);
+			ret = -EINTR;
+		}
+		xas_unlock(&xas);
+
+		/* Someone will complete it soon. */
+		if (ret != -EINTR) {
+			cpu_relax();
+			goto wait;
+		}
+	}
 	cachefiles_req_put(req);
 	return ret;
 out:
-- 
2.39.2


  parent reply	other threads:[~2024-05-15  8:57 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-15  8:45 [PATCH v2 00/12] cachefiles: some bugfixes and cleanups for ondemand requests libaokun
2024-05-15  8:45 ` [PATCH v2 01/12] cachefiles: remove request from xarry during flush requests libaokun
2024-05-20  2:20   ` Gao Xiang
2024-05-20  4:11     ` Baokun Li
2024-05-20  7:09   ` Jingbo Xu
2024-05-15  8:45 ` [PATCH v2 02/12] cachefiles: remove err_put_fd tag in cachefiles_ondemand_daemon_read() libaokun
2024-05-20  2:23   ` Gao Xiang
2024-05-20  4:15     ` Baokun Li
2024-05-15  8:45 ` [PATCH v2 03/12] cachefiles: fix slab-use-after-free in cachefiles_ondemand_get_fd() libaokun
2024-05-20  7:24   ` Jingbo Xu
2024-05-20  8:38     ` Baokun Li
2024-05-20  8:45       ` Gao Xiang
2024-05-20  9:10       ` Jingbo Xu
2024-05-20  9:19         ` Baokun Li
2024-05-20 12:22         ` Baokun Li
2024-05-20  8:06   ` Jingbo Xu
2024-05-20  9:10     ` Baokun Li
2024-05-15  8:45 ` [PATCH v2 04/12] cachefiles: fix slab-use-after-free in cachefiles_ondemand_daemon_read() libaokun
2024-05-20  7:36   ` Jingbo Xu
2024-05-20  8:56     ` Baokun Li
2024-05-15  8:45 ` [PATCH v2 05/12] cachefiles: add output string to cachefiles_obj_[get|put]_ondemand_fd libaokun
2024-05-20  7:40   ` Jingbo Xu
2024-05-20  9:02     ` Baokun Li
2024-05-15  8:45 ` [PATCH v2 06/12] cachefiles: add consistency check for copen/cread libaokun
2024-05-15  8:45 ` [PATCH v2 07/12] cachefiles: add spin_lock for cachefiles_ondemand_info libaokun
2024-05-15  8:45 ` [PATCH v2 08/12] cachefiles: never get a new anonymous fd if ondemand_id is valid libaokun
2024-05-20  8:43   ` Jingbo Xu
2024-05-20  9:07     ` Baokun Li
2024-05-20  9:24       ` Jingbo Xu
2024-05-20 11:14         ` Baokun Li
2024-05-20 11:24           ` Gao Xiang
2024-05-15  8:45 ` [PATCH v2 09/12] cachefiles: defer exposing anon_fd until after copy_to_user() succeeds libaokun
2024-05-20  9:39   ` Jingbo Xu
2024-05-20 11:36     ` Baokun Li
2024-05-15  8:45 ` [PATCH v2 10/12] cachefiles: Set object to close if ondemand_id < 0 in copen libaokun
2024-05-15  8:46 ` [PATCH v2 11/12] cachefiles: flush all requests after setting CACHEFILES_DEAD libaokun
2024-05-15  8:46 ` libaokun [this message]
2024-05-19 10:56 ` [PATCH v2 00/12] cachefiles: some bugfixes and cleanups for ondemand requests Jeff Layton

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