Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-qa0-f45.google.com ([209.85.216.45]:51309 "EHLO mail-qa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751377AbaHOOot (ORCPT ); Fri, 15 Aug 2014 10:44:49 -0400 Received: by mail-qa0-f45.google.com with SMTP id cm18so2104787qab.4 for ; Fri, 15 Aug 2014 07:44:48 -0700 (PDT) Received: from tlielax.poochiereds.net ([2001:470:8:d63:3a60:77ff:fe93:a95d]) by mx.google.com with ESMTPSA id i2sm9046955qge.27.2014.08.15.07.44.47 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 15 Aug 2014 07:44:47 -0700 (PDT) From: Jeff Layton To: linux-nfs@vger.kernel.org Subject: [kernel RFC PATCH 1/4] lockd: add a /proc/fs/lockd/nlm_end_grace file Date: Fri, 15 Aug 2014 10:44:37 -0400 Message-Id: <1408113880-5489-2-git-send-email-jlayton@primarydata.com> In-Reply-To: <1408113880-5489-1-git-send-email-jlayton@primarydata.com> References: <1408113880-5489-1-git-send-email-jlayton@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: Add a new procfile that will allow a (privileged) userland process to end the NLM grace period early. The basic idea here will be to have sm-notify write to this file, if it sent out no NOTIFY requests when it runs. In that situation, we can generally expect that there will be no reclaim requests so the grace period can be lifted early. Signed-off-by: Jeff Layton --- fs/lockd/Makefile | 1 + fs/lockd/procfs.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ fs/lockd/procfs.h | 28 ++++++++++++++++++++ fs/lockd/svc.c | 9 +++++++ 4 files changed, 114 insertions(+) create mode 100644 fs/lockd/procfs.c create mode 100644 fs/lockd/procfs.h diff --git a/fs/lockd/Makefile b/fs/lockd/Makefile index ca58d64374ca..bc28fff5d305 100644 --- a/fs/lockd/Makefile +++ b/fs/lockd/Makefile @@ -7,4 +7,5 @@ obj-$(CONFIG_LOCKD) += lockd.o lockd-objs-y := clntlock.o clntproc.o clntxdr.o host.o svc.o svclock.o \ svcshare.o svcproc.o svcsubs.o mon.o xdr.o grace.o lockd-objs-$(CONFIG_LOCKD_V4) += clnt4xdr.o xdr4.o svc4proc.o +lockd-objs-$(CONFIG_PROC_FS) += procfs.o lockd-objs := $(lockd-objs-y) diff --git a/fs/lockd/procfs.c b/fs/lockd/procfs.c new file mode 100644 index 000000000000..dfd708fa43a3 --- /dev/null +++ b/fs/lockd/procfs.c @@ -0,0 +1,76 @@ +/* + * Procfs support for lockd + * + * Copyright (c) 2014 Jeff Layton + */ + +#include +#include +#include +#include +#include + +#include "netns.h" +#include "procfs.h" + +/* + * Just check to see if the data written is longer than zero length. We + * don't really care what's in the data, just that someone wrote something + * to the file. + */ +static ssize_t +nlm_end_grace_write(struct file *file, const char __user *buf, size_t size, + loff_t *pos) +{ + struct lockd_net *ln = net_generic(current->nsproxy->net_ns, lockd_net_id); + + if (size > 0) + locks_end_grace(&ln->lockd_manager); + + return size; +} + +static ssize_t +nlm_end_grace_read(struct file *file, char __user *buf, size_t size, + loff_t *pos) +{ + struct lockd_net *ln = net_generic(current->nsproxy->net_ns, lockd_net_id); + char resp[3]; + + resp[0] = list_empty(&ln->lockd_manager.list) ? 'Y' : 'N'; + resp[1] = '\n'; + resp[2] = '\0'; + + return simple_read_from_buffer(buf, size, pos, resp, sizeof(resp)); +} + +static const struct file_operations lockd_end_grace_operations = { + .write = nlm_end_grace_write, + .read = nlm_end_grace_read, + .llseek = default_llseek, + .owner = THIS_MODULE, +}; + +int __init +lockd_create_procfs(void) +{ + struct proc_dir_entry *entry; + + entry = proc_mkdir("fs/lockd", NULL); + if (!entry) + return -ENOMEM; + entry = proc_create("nlm_end_grace", S_IRUGO|S_IWUSR, entry, + &lockd_end_grace_operations); + if (!entry) { + remove_proc_entry("fs/lockd", NULL); + return -ENOMEM; + } + return 0; +} + +void __exit +lockd_remove_procfs(void) +{ + remove_proc_entry("fs/lockd/nlm_end_grace", NULL); + remove_proc_entry("fs/lockd", NULL); +} diff --git a/fs/lockd/procfs.h b/fs/lockd/procfs.h new file mode 100644 index 000000000000..2257a1311027 --- /dev/null +++ b/fs/lockd/procfs.h @@ -0,0 +1,28 @@ +/* + * Procfs support for lockd + * + * Copyright (c) 2014 Jeff Layton + */ +#ifndef _LOCKD_PROCFS_H +#define _LOCKD_PROCFS_H + +#include + +#if IS_ENABLED(CONFIG_PROC_FS) +int lockd_create_procfs(void); +void lockd_remove_procfs(void); +#else +static inline int +lockd_create_procfs(void) +{ + return 0; +} + +static inline void +lockd_remove_procfs(void) +{ + return; +} +#endif /* IS_ENABLED(CONFIG_PROC_FS) */ + +#endif /* _LOCKD_PROCFS_H */ diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c index 8f27c93f8d2e..21223f15c00e 100644 --- a/fs/lockd/svc.c +++ b/fs/lockd/svc.c @@ -36,6 +36,7 @@ #include #include "netns.h" +#include "procfs.h" #define NLMDBG_FACILITY NLMDBG_SVC #define LOCKD_BUFSIZE (1024 + NLMSVC_XDRSIZE) @@ -617,8 +618,15 @@ static int __init init_nlm(void) err = register_pernet_subsys(&lockd_net_ops); if (err) goto err_pernet; + + err = lockd_create_procfs(); + if (err) + goto err_procfs; + return 0; +err_procfs: + unregister_pernet_subsys(&lockd_net_ops); err_pernet: #ifdef CONFIG_SYSCTL unregister_sysctl_table(nlm_sysctl_table); @@ -631,6 +639,7 @@ static void __exit exit_nlm(void) { /* FIXME: delete all NLM clients */ nlm_shutdown_hosts(); + lockd_remove_procfs(); unregister_pernet_subsys(&lockd_net_ops); #ifdef CONFIG_SYSCTL unregister_sysctl_table(nlm_sysctl_table); -- 1.9.3