original development tree for Linux kernel GTP module; now long in mainline.
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/*
* Copyright (c) 2012 Bryan Schumaker <bjschuma@netapp.com>
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/nfs_idmap.h>
#include <linux/nfs4_mount.h>
#include <linux/nfs_fs.h>
#include "internal.h"
#include "nfs4_fs.h"
#include "nfs.h"
#define NFSDBG_FACILITY NFSDBG_VFS
static struct dentry *nfs4_remote_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *raw_data);
static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *raw_data);
static struct dentry *nfs4_remote_referral_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *raw_data);
static struct file_system_type nfs4_fs_type = {
.owner = THIS_MODULE,
.name = "nfs4",
.mount = nfs_fs_mount,
.kill_sb = nfs_kill_super,
.fs_flags = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
};
static struct file_system_type nfs4_remote_fs_type = {
.owner = THIS_MODULE,
.name = "nfs4",
.mount = nfs4_remote_mount,
.kill_sb = nfs_kill_super,
.fs_flags = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
};
static struct file_system_type nfs4_remote_referral_fs_type = {
.owner = THIS_MODULE,
.name = "nfs4",
.mount = nfs4_remote_referral_mount,
.kill_sb = nfs_kill_super,
.fs_flags = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
};
struct file_system_type nfs4_referral_fs_type = {
.owner = THIS_MODULE,
.name = "nfs4",
.mount = nfs4_referral_mount,
.kill_sb = nfs_kill_super,
.fs_flags = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
};
static const struct super_operations nfs4_sops = {
.alloc_inode = nfs_alloc_inode,
.destroy_inode = nfs_destroy_inode,
.write_inode = nfs4_write_inode,
.put_super = nfs_put_super,
.statfs = nfs_statfs,
.evict_inode = nfs4_evict_inode,
.umount_begin = nfs_umount_begin,
.show_options = nfs_show_options,
.show_devname = nfs_show_devname,
.show_path = nfs_show_path,
.show_stats = nfs_show_stats,
.remount_fs = nfs_remount,
};
struct nfs_subversion nfs_v4 = {
.owner = THIS_MODULE,
.nfs_fs = &nfs4_fs_type,
.rpc_vers = &nfs_version4,
.rpc_ops = &nfs_v4_clientops,
};
/*
* Set up an NFS4 superblock
*/
static void nfs4_fill_super(struct super_block *sb,
struct nfs_mount_info *mount_info)
{
sb->s_time_gran = 1;
sb->s_op = &nfs4_sops;
/*
* The VFS shouldn't apply the umask to mode bits. We will do
* so ourselves when necessary.
*/
sb->s_flags |= MS_POSIXACL;
sb->s_xattr = nfs4_xattr_handlers;
nfs_initialise_sb(sb);
}
/*
* Get the superblock for the NFS4 root partition
*/
static struct dentry *
nfs4_remote_mount(struct file_system_type *fs_type, int flags,
const char *dev_name, void *info)
{
struct nfs_mount_info *mount_info = info;
struct nfs_server *server;
struct dentry *mntroot = ERR_PTR(-ENOMEM);
mount_info->fill_super = nfs4_fill_super;
mount_info->set_security = nfs_set_sb_security;
/* Get a volume representation */
server = nfs4_create_server(mount_info->parsed, mount_info->mntfh);
if (IS_ERR(server)) {
mntroot = ERR_CAST(server);
goto out;
}
mntroot = nfs_fs_mount_common(server, flags, dev_name, mount_info, &nfs_v4);
out:
return mntroot;
}
static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
int flags, void *data, const char *hostname)
{
struct vfsmount *root_mnt;
char *root_devname;
size_t len;
len = strlen(hostname) + 5;
root_devname = kmalloc(len, GFP_KERNEL);
if (root_devname == NULL)
return ERR_PTR(-ENOMEM);
/* Does hostname needs to be enclosed in brackets? */
if (strchr(hostname, ':'))
snprintf(root_devname, len, "[%s]:/", hostname);
else
snprintf(root_devname, len, "%s:/", hostname);
root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
kfree(root_devname);
return root_mnt;
}
struct nfs_referral_count {
struct list_head list;
const struct task_struct *task;
unsigned int referral_count;
};
static LIST_HEAD(nfs_referral_count_list);
static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
static struct nfs_referral_count *nfs_find_referral_count(void)
{
struct nfs_referral_count *p;
list_for_each_entry(p, &nfs_referral_count_list, list) {
if (p->task == current)
return p;
}
return NULL;
}
#define NFS_MAX_NESTED_REFERRALS 2
static int nfs_referral_loop_protect(void)
{
struct nfs_referral_count *p, *new;
int ret = -ENOMEM;
new = kmalloc(sizeof(*new), GFP_KERNEL);
if (!new)
goto out;
new->task = current;
new->referral_count = 1;
ret = 0;
spin_lock(&nfs_referral_count_list_lock);
p = nfs_find_referral_count();
if (p != NULL) {
if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
ret = -ELOOP;
else
p->referral_count++;
} else {
list_add(&new->list, &nfs_referral_count_list);
new = NULL;
}
spin_unlock(&nfs_referral_count_list_lock);
kfree(new);
out:
return ret;
}
static void nfs_referral_loop_unprotect(void)
{
struct nfs_referral_count *p;
spin_lock(&nfs_referral_count_list_lock);
p = nfs_find_referral_count();
p->referral_count--;
if (p->referral_count == 0)
list_del(&p->list);
else
p = NULL;
spin_unlock(&nfs_referral_count_list_lock);
kfree(p);
}
static struct dentry *nfs_follow_remote_path(struct vfsmount *root_mnt,
const char *export_path)
{
struct dentry *dentry;
int err;
if (IS_ERR(root_mnt))
return ERR_CAST(root_mnt);
err = nfs_referral_loop_protect();
if (err) {
mntput(root_mnt);
return ERR_PTR(err);
}
dentry = mount_subtree(root_mnt, export_path);
nfs_referral_loop_unprotect();
return dentry;
}
struct dentry *nfs4_try_mount(int flags, const char *dev_name,
struct nfs_mount_info *mount_info)
{
char *export_path;
struct vfsmount *root_mnt;
struct dentry *res;
struct nfs_parsed_mount_data *data = mount_info->parsed;
dfprintk(MOUNT, "--> nfs4_try_mount()\n");
mount_info->fill_super = nfs4_fill_super;
export_path = data->nfs_server.export_path;
data->nfs_server.export_path = "/";
root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, mount_info,
data->nfs_server.hostname);
data->nfs_server.export_path = export_path;
res = nfs_follow_remote_path(root_mnt, export_path);
dfprintk(MOUNT, "<-- nfs4_try_mount() = %ld%s\n",
IS_ERR(res) ? PTR_ERR(res) : 0,
IS_ERR(res) ? " [error]" : "");
return res;
}
static struct dentry *
nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
const char *dev_name, void *raw_data)
{
struct nfs_mount_info mount_info = {
.fill_super = nfs4_fill_super,
.set_security = nfs_clone_sb_security,
.cloned = raw_data,
};
struct nfs_server *server;
struct dentry *mntroot = ERR_PTR(-ENOMEM);
dprintk("--> nfs4_referral_get_sb()\n");
mount_info.mntfh = nfs_alloc_fhandle();
if (mount_info.cloned == NULL || mount_info.mntfh == NULL)
goto out;
/* create a new volume representation */
server = nfs4_create_referral_server(mount_info.cloned, mount_info.mntfh);
if (IS_ERR(server)) {
mntroot = ERR_CAST(server);
goto out;
}
mntroot = nfs_fs_mount_common(server, flags, dev_name, &mount_info, &nfs_v4);
out:
nfs_free_fhandle(mount_info.mntfh);
return mntroot;
}
/*
* Create an NFS4 server record on referral traversal
*/
static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *raw_data)
{
struct nfs_clone_mount *data = raw_data;
char *export_path;
struct vfsmount *root_mnt;
struct dentry *res;
dprintk("--> nfs4_referral_mount()\n");
export_path = data->mnt_path;
data->mnt_path = "/";
root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
flags, data, data->hostname);
data->mnt_path = export_path;
res = nfs_follow_remote_path(root_mnt, export_path);
dprintk("<-- nfs4_referral_mount() = %ld%s\n",
IS_ERR(res) ? PTR_ERR(res) : 0,
IS_ERR(res) ? " [error]" : "");
return res;
}
int __init init_nfs_v4(void)
{
int err;
err = nfs_idmap_init();
if (err)
goto out;
err = nfs4_register_sysctl();
if (err)
goto out1;
err = register_filesystem(&nfs4_fs_type);
if (err < 0)
goto out2;
register_nfs_version(&nfs_v4);
return 0;
out2:
nfs4_unregister_sysctl();
out1:
nfs_idmap_quit();
out:
return err;
}
void exit_nfs_v4(void)
{
unregister_nfs_version(&nfs_v4);
unregister_filesystem(&nfs4_fs_type);
nfs4_unregister_sysctl();
nfs_idmap_quit();
}