linux/fs/nfs/nfs4super.c
bjschuma@gmail.com 1ae811ee27 NFS: Fix a regression when loading the NFS v4 module
Some systems have a modprobe.d/nfs.conf file that sets an nfs4 alias
pointing to nfs.ko, rather than nfs4.ko.  This can prevent the v4 module
from loading on mount, since the kernel sees that something named "nfs4"
has already been loaded.  To work around this, I've renamed the modules
to "nfsv2.ko" "nfsv3.ko" and "nfsv4.ko".

I also had to move the nfs4_fs_type back to nfs.ko to ensure that `mount
-t nfs4` still works.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-08-16 16:15:49 -04:00

358 lines
8.6 KiB
C

/*
* 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 "delegation.h"
#include "internal.h"
#include "nfs4_fs.h"
#include "pnfs.h"
#include "nfs.h"
#define NFSDBG_FACILITY NFSDBG_VFS
static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc);
static void nfs4_evict_inode(struct inode *inode);
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_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,
.sops = &nfs4_sops,
.xattr = nfs4_xattr_handlers,
};
static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc)
{
int ret = nfs_write_inode(inode, wbc);
if (ret >= 0 && test_bit(NFS_INO_LAYOUTCOMMIT, &NFS_I(inode)->flags)) {
int status;
bool sync = true;
if (wbc->sync_mode == WB_SYNC_NONE)
sync = false;
status = pnfs_layoutcommit_inode(inode, sync);
if (status < 0)
return status;
}
return ret;
}
/*
* Clean out any remaining NFSv4 state that might be left over due
* to open() calls that passed nfs_atomic_lookup, but failed to call
* nfs_open().
*/
static void nfs4_evict_inode(struct inode *inode)
{
truncate_inode_pages(&inode->i_data, 0);
clear_inode(inode);
pnfs_return_layout(inode);
pnfs_destroy_layout(NFS_I(inode));
/* If we are holding a delegation, return it! */
nfs_inode_return_delegation_noreclaim(inode);
/* First call standard NFS clear_inode() code */
nfs_clear_inode(inode);
}
/*
* 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->set_security = nfs_set_sb_security;
/* Get a volume representation */
server = nfs4_create_server(mount_info, &nfs_v4);
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,
struct nfs_subversion *nfs_mod)
{
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");
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 = nfs_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;
}
static int __init init_nfs_v4(void)
{
int err;
err = nfs_idmap_init();
if (err)
goto out;
err = nfs4_register_sysctl();
if (err)
goto out1;
register_nfs_version(&nfs_v4);
return 0;
out1:
nfs_idmap_quit();
out:
return err;
}
static void __exit exit_nfs_v4(void)
{
unregister_nfs_version(&nfs_v4);
nfs4_unregister_sysctl();
nfs_idmap_quit();
}
MODULE_LICENSE("GPL");
module_init(init_nfs_v4);
module_exit(exit_nfs_v4);