NFS: Fix /proc/fs/nfsfs/servers and /proc/fs/nfsfs/volumes
The usage of pid_ns->child_reaper->nsproxy->net_ns in nfs_server_list_open and nfs_client_list_open is not safe. /proc for a pid namespace can remain mounted after the all of the process in that pid namespace have exited. There are also times before the initial process in a pid namespace has started or after the initial process in a pid namespace has exited where pid_ns->child_reaper can be NULL or stale. Making the idiom pid_ns->child_reaper->nsproxy a double whammy of problems. Luckily all that needs to happen is to move /proc/fs/nfsfs/servers and /proc/fs/nfsfs/volumes under /proc/net to /proc/net/nfsfs/servers and /proc/net/nfsfs/volumes and add a symlink from the original location, and to use seq_open_net as it has been designed. Cc: stable@vger.kernel.org Cc: Trond Myklebust <trond.myklebust@primarydata.com> Cc: Stanislav Kinsbursky <skinsbursky@parallels.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
This commit is contained in:
Eric W. Biederman
parent
db181ce011
commit
65b38851a1
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@ -1205,7 +1205,7 @@ static const struct file_operations nfs_server_list_fops = {
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.open = nfs_server_list_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = seq_release,
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.release = seq_release_net,
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.owner = THIS_MODULE,
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};
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@ -1226,7 +1226,7 @@ static const struct file_operations nfs_volume_list_fops = {
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.open = nfs_volume_list_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = seq_release,
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.release = seq_release_net,
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.owner = THIS_MODULE,
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};
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@ -1236,19 +1236,8 @@ static const struct file_operations nfs_volume_list_fops = {
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*/
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static int nfs_server_list_open(struct inode *inode, struct file *file)
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{
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struct seq_file *m;
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int ret;
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struct pid_namespace *pid_ns = file->f_dentry->d_sb->s_fs_info;
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struct net *net = pid_ns->child_reaper->nsproxy->net_ns;
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ret = seq_open(file, &nfs_server_list_ops);
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if (ret < 0)
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return ret;
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m = file->private_data;
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m->private = net;
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return 0;
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return seq_open_net(inode, file, &nfs_server_list_ops,
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sizeof(struct seq_net_private));
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}
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/*
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@ -1256,7 +1245,7 @@ static int nfs_server_list_open(struct inode *inode, struct file *file)
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*/
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static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
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{
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struct nfs_net *nn = net_generic(m->private, nfs_net_id);
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struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
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/* lock the list against modification */
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spin_lock(&nn->nfs_client_lock);
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@ -1268,7 +1257,7 @@ static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
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*/
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static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos)
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{
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struct nfs_net *nn = net_generic(p->private, nfs_net_id);
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struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
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return seq_list_next(v, &nn->nfs_client_list, pos);
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}
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@ -1278,7 +1267,7 @@ static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos)
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*/
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static void nfs_server_list_stop(struct seq_file *p, void *v)
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{
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struct nfs_net *nn = net_generic(p->private, nfs_net_id);
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struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
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spin_unlock(&nn->nfs_client_lock);
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}
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@ -1289,7 +1278,7 @@ static void nfs_server_list_stop(struct seq_file *p, void *v)
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static int nfs_server_list_show(struct seq_file *m, void *v)
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{
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struct nfs_client *clp;
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struct nfs_net *nn = net_generic(m->private, nfs_net_id);
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struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
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/* display header on line 1 */
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if (v == &nn->nfs_client_list) {
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@ -1321,19 +1310,8 @@ static int nfs_server_list_show(struct seq_file *m, void *v)
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*/
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static int nfs_volume_list_open(struct inode *inode, struct file *file)
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{
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struct seq_file *m;
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int ret;
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struct pid_namespace *pid_ns = file->f_dentry->d_sb->s_fs_info;
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struct net *net = pid_ns->child_reaper->nsproxy->net_ns;
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ret = seq_open(file, &nfs_volume_list_ops);
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if (ret < 0)
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return ret;
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m = file->private_data;
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m->private = net;
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return 0;
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return seq_open_net(inode, file, &nfs_server_list_ops,
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sizeof(struct seq_net_private));
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}
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/*
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@ -1341,7 +1319,7 @@ static int nfs_volume_list_open(struct inode *inode, struct file *file)
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*/
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static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos)
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{
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struct nfs_net *nn = net_generic(m->private, nfs_net_id);
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struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
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/* lock the list against modification */
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spin_lock(&nn->nfs_client_lock);
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@ -1353,7 +1331,7 @@ static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos)
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*/
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static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos)
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{
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struct nfs_net *nn = net_generic(p->private, nfs_net_id);
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struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
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return seq_list_next(v, &nn->nfs_volume_list, pos);
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}
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@ -1363,7 +1341,7 @@ static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos)
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*/
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static void nfs_volume_list_stop(struct seq_file *p, void *v)
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{
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struct nfs_net *nn = net_generic(p->private, nfs_net_id);
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struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
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spin_unlock(&nn->nfs_client_lock);
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}
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@ -1376,7 +1354,7 @@ static int nfs_volume_list_show(struct seq_file *m, void *v)
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struct nfs_server *server;
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struct nfs_client *clp;
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char dev[8], fsid[17];
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struct nfs_net *nn = net_generic(m->private, nfs_net_id);
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struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
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/* display header on line 1 */
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if (v == &nn->nfs_volume_list) {
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@ -1407,6 +1385,45 @@ static int nfs_volume_list_show(struct seq_file *m, void *v)
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return 0;
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}
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int nfs_fs_proc_net_init(struct net *net)
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{
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struct nfs_net *nn = net_generic(net, nfs_net_id);
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struct proc_dir_entry *p;
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nn->proc_nfsfs = proc_net_mkdir(net, "nfsfs", net->proc_net);
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if (!nn->proc_nfsfs)
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goto error_0;
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/* a file of servers with which we're dealing */
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p = proc_create("servers", S_IFREG|S_IRUGO,
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nn->proc_nfsfs, &nfs_server_list_fops);
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if (!p)
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goto error_1;
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/* a file of volumes that we have mounted */
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p = proc_create("volumes", S_IFREG|S_IRUGO,
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nn->proc_nfsfs, &nfs_volume_list_fops);
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if (!p)
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goto error_2;
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return 0;
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error_2:
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remove_proc_entry("servers", nn->proc_nfsfs);
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error_1:
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remove_proc_entry("fs/nfsfs", NULL);
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error_0:
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return -ENOMEM;
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}
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void nfs_fs_proc_net_exit(struct net *net)
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{
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struct nfs_net *nn = net_generic(net, nfs_net_id);
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remove_proc_entry("volumes", nn->proc_nfsfs);
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remove_proc_entry("servers", nn->proc_nfsfs);
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remove_proc_entry("fs/nfsfs", NULL);
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}
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/*
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* initialise the /proc/fs/nfsfs/ directory
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*/
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@ -1419,14 +1436,12 @@ int __init nfs_fs_proc_init(void)
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goto error_0;
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/* a file of servers with which we're dealing */
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p = proc_create("servers", S_IFREG|S_IRUGO,
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proc_fs_nfs, &nfs_server_list_fops);
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p = proc_symlink("servers", proc_fs_nfs, "../../net/nfsfs/servers");
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if (!p)
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goto error_1;
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/* a file of volumes that we have mounted */
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p = proc_create("volumes", S_IFREG|S_IRUGO,
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proc_fs_nfs, &nfs_volume_list_fops);
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p = proc_symlink("volumes", proc_fs_nfs, "../../net/nfsfs/volumes");
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if (!p)
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goto error_2;
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return 0;
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@ -1840,11 +1840,12 @@ EXPORT_SYMBOL_GPL(nfs_net_id);
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static int nfs_net_init(struct net *net)
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{
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nfs_clients_init(net);
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return 0;
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return nfs_fs_proc_net_init(net);
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}
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static void nfs_net_exit(struct net *net)
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{
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nfs_fs_proc_net_exit(net);
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nfs_cleanup_cb_ident_idr(net);
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}
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@ -195,7 +195,16 @@ extern struct rpc_clnt *nfs4_find_or_create_ds_client(struct nfs_client *,
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#ifdef CONFIG_PROC_FS
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extern int __init nfs_fs_proc_init(void);
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extern void nfs_fs_proc_exit(void);
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extern int nfs_fs_proc_net_init(struct net *net);
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extern void nfs_fs_proc_net_exit(struct net *net);
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#else
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static inline int nfs_fs_proc_net_init(struct net *net)
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{
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return 0;
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}
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static inline void nfs_fs_proc_net_exit(struct net *net)
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{
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}
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static inline int nfs_fs_proc_init(void)
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{
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return 0;
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@ -29,6 +29,9 @@ struct nfs_net {
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#endif
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spinlock_t nfs_client_lock;
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struct timespec boot_time;
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#ifdef CONFIG_PROC_FS
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struct proc_dir_entry *proc_nfsfs;
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#endif
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};
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extern int nfs_net_id;
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