forked from luck/tmp_suning_uos_patched
d68e3c4aa4
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 <jlayton@primarydata.com>
93 lines
1.8 KiB
C
93 lines
1.8 KiB
C
/*
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* Procfs support for lockd
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*
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* Copyright (c) 2014 Jeff Layton <jlayton@primarydata.com>
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*/
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#include <linux/fs.h>
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#include <linux/proc_fs.h>
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#include <linux/module.h>
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#include <linux/nsproxy.h>
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#include <net/net_namespace.h>
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#include "netns.h"
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#include "procfs.h"
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/*
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* We only allow strings that start with 'Y', 'y', or '1'.
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*/
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static ssize_t
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nlm_end_grace_write(struct file *file, const char __user *buf, size_t size,
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loff_t *pos)
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{
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char *data;
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struct lockd_net *ln = net_generic(current->nsproxy->net_ns,
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lockd_net_id);
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if (size < 1)
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return -EINVAL;
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data = simple_transaction_get(file, buf, size);
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if (IS_ERR(data))
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return PTR_ERR(data);
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switch(data[0]) {
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case 'Y':
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case 'y':
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case '1':
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locks_end_grace(&ln->lockd_manager);
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break;
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default:
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return -EINVAL;
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}
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return size;
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}
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static ssize_t
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nlm_end_grace_read(struct file *file, char __user *buf, size_t size,
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loff_t *pos)
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{
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struct lockd_net *ln = net_generic(current->nsproxy->net_ns,
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lockd_net_id);
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char resp[3];
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resp[0] = list_empty(&ln->lockd_manager.list) ? 'Y' : 'N';
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resp[1] = '\n';
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resp[2] = '\0';
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return simple_read_from_buffer(buf, size, pos, resp, sizeof(resp));
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}
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static const struct file_operations lockd_end_grace_operations = {
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.write = nlm_end_grace_write,
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.read = nlm_end_grace_read,
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.llseek = default_llseek,
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.release = simple_transaction_release,
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.owner = THIS_MODULE,
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};
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int __init
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lockd_create_procfs(void)
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{
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struct proc_dir_entry *entry;
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entry = proc_mkdir("fs/lockd", NULL);
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if (!entry)
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return -ENOMEM;
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entry = proc_create("nlm_end_grace", S_IRUGO|S_IWUSR, entry,
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&lockd_end_grace_operations);
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if (!entry) {
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remove_proc_entry("fs/lockd", NULL);
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return -ENOMEM;
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}
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return 0;
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}
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void __exit
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lockd_remove_procfs(void)
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{
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remove_proc_entry("fs/lockd/nlm_end_grace", NULL);
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remove_proc_entry("fs/lockd", NULL);
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}
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