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From: libaokun@huaweicloud.com
To: netfs@lists.linux.dev
Cc: dhowells@redhat.com, jlayton@kernel.org, zhujia.zj@bytedance.com,
	jefflexu@linux.alibaba.com, linux-erofs@lists.ozlabs.org,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	libaokun@huaweicloud.com, Baokun Li <libaokun1@huawei.com>,
	Hou Tao <houtao1@huawei.com>
Subject: [PATCH 12/12] cachefiles: make on-demand read killable
Date: Wed, 24 Apr 2024 11:39:16 +0800	[thread overview]
Message-ID: <20240424033916.2748488-13-libaokun@huaweicloud.com> (raw)
In-Reply-To: <20240424033916.2748488-1-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>
---
 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 673e7ad52041..b766430f4abf 100644
--- a/fs/cachefiles/ondemand.c
+++ b/fs/cachefiles/ondemand.c
@@ -525,8 +525,25 @@ 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:[~2024-04-24  3:48 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-24  3:39 [PATCH 00/12] cachefiles: some bugfixes and cleanups for ondemand requests libaokun
2024-04-24  3:39 ` [PATCH 01/12] cachefiles: remove request from xarry during flush requests libaokun
2024-04-25  3:13   ` Jia Zhu
2024-05-06  3:48   ` Jingbo Xu
2024-05-06  3:57     ` Baokun Li
2024-05-06  5:50       ` Jingbo Xu
2024-05-07  6:52         ` Baokun Li
2024-04-24  3:39 ` [PATCH 02/12] cachefiles: remove err_put_fd tag in cachefiles_ondemand_daemon_read() libaokun
2024-04-25  3:17   ` Jia Zhu
2024-05-06  3:55   ` Jingbo Xu
2024-05-06  4:02     ` Baokun Li
2024-04-24  3:39 ` [PATCH 03/12] cachefiles: fix slab-use-after-free in cachefiles_ondemand_get_fd() libaokun
2024-04-24 14:55   ` Jia Zhu
2024-04-25  1:33     ` Baokun Li
2024-04-25  3:39   ` Jia Zhu
2024-04-24  3:39 ` [PATCH 04/12] cachefiles: fix slab-use-after-free in cachefiles_ondemand_daemon_read() libaokun
2024-04-25  3:42   ` [External] " Jia Zhu
2024-04-24  3:39 ` [PATCH 05/12] cachefiles: add output string to cachefiles_obj_[get|put]_ondemand_fd libaokun
2024-04-24  3:39 ` [PATCH 06/12] cachefiles: add consistency check for copen/cread libaokun
2024-05-06  2:31   ` Jingbo Xu
2024-05-06  3:12     ` Baokun Li
2024-04-24  3:39 ` [PATCH 07/12] cachefiles: add spin_lock for cachefiles_ondemand_info libaokun
2024-05-06  2:55   ` Jingbo Xu
2024-05-06  3:23     ` Baokun Li
2024-04-24  3:39 ` [PATCH 08/12] cachefiles: never get a new anon fd if ondemand_id is valid libaokun
2024-05-06  3:09   ` Jingbo Xu
2024-05-07  9:32     ` Baokun Li
2024-04-24  3:39 ` [PATCH 09/12] cachefiles: defer exposing anon_fd until after copy_to_user() succeeds libaokun
2024-05-06  3:24   ` Jingbo Xu
2024-05-06  3:34     ` Baokun Li
2024-04-24  3:39 ` [PATCH 10/12] cachefiles: Set object to close if ondemand_id < 0 in copen libaokun
2024-04-25  4:56   ` Jia Zhu
2024-04-24  3:39 ` [PATCH 11/12] cachefiles: flush all requests after setting CACHEFILES_DEAD libaokun
2024-04-24  3:39 ` libaokun [this message]
2024-04-25  5:15   ` [PATCH 12/12] cachefiles: make on-demand read killable Jia Zhu

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