From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6BC84BA49 for ; Tue, 7 Mar 2023 18:56:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C6938C433A0; Tue, 7 Mar 2023 18:56:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678215395; bh=4zL1DFwV9lIDQn9hCH+nHisjZvkZbrzu1hIMQfTM7c4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=c4bQuofuOIJG5uPpA0zVHImUG690OT3O3V7t5mrR2aa+iH0z+tl7brssXAHS5RRBr xfp+4gP8xvRToQxmM/gNIdSH67XcXIzRXiU9P7oIUa9B9Fcw2MAvZUK0S1p8lJqZr/ G0hrGrRfg/4th69jCAOZtH0cDFNiG8pd2GeitdT8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Olga Kornievskaia , NeilBrown , Anna Schumaker , Sasha Levin Subject: [PATCH 5.15 247/567] NFS: fix disabling of swap Date: Tue, 7 Mar 2023 17:59:43 +0100 Message-Id: <20230307165916.669838741@linuxfoundation.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230307165905.838066027@linuxfoundation.org> References: <20230307165905.838066027@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: NeilBrown [ Upstream commit 5bab56fff53ce161ed859d9559a10361d4f79578 ] When swap is activated to a file on an NFSv4 mount we arrange that the state manager thread is always present as starting a new thread requires memory allocations that might block waiting for swap. Unfortunately the code for allowing the state manager thread to exit when swap is disabled was not tested properly and does not work. This can be seen by examining /proc/fs/nfsfs/servers after disabling swap and unmounting the filesystem. The servers file will still list one entry. Also a "ps" listing will show the state manager thread is still present. There are two problems. 1/ rpc_clnt_swap_deactivate() doesn't walk up the ->cl_parent list to find the primary client on which the state manager runs. 2/ The thread is not woken up properly and it immediately goes back to sleep without checking whether it is really needed. Using nfs4_schedule_state_manager() ensures a proper wake-up. Reported-by: Olga Kornievskaia Fixes: 4dc73c679114 ("NFSv4: keep state manager thread active if swap is enabled") Signed-off-by: NeilBrown Signed-off-by: Anna Schumaker Signed-off-by: Sasha Levin --- fs/nfs/nfs4proc.c | 4 +++- net/sunrpc/clnt.c | 2 ++ 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 5b671ca429d2b..27cafeada8651 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -10545,7 +10545,9 @@ static void nfs4_disable_swap(struct inode *inode) /* The state manager thread will now exit once it is * woken. */ - wake_up_var(&NFS_SERVER(inode)->nfs_client->cl_state); + struct nfs_client *clp = NFS_SERVER(inode)->nfs_client; + + nfs4_schedule_state_manager(clp); } static const struct inode_operations nfs4_dir_inode_operations = { diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index 6622dc1fa8f2f..ad3e9a40b0610 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -3138,6 +3138,8 @@ rpc_clnt_swap_deactivate_callback(struct rpc_clnt *clnt, void rpc_clnt_swap_deactivate(struct rpc_clnt *clnt) { + while (clnt != clnt->cl_parent) + clnt = clnt->cl_parent; if (atomic_dec_if_positive(&clnt->cl_swapper) == 0) rpc_clnt_iterate_for_each_xprt(clnt, rpc_clnt_swap_deactivate_callback, NULL); -- 2.39.2