blob: 8da5a9c000f42c3eda0d3b1f35ca45be96a253ae [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2012 Bryan Schumaker <bjschuma@netapp.com>
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/nfs4_mount.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_ssc.h>
#include "delegation.h"
#include "internal.h"
#include "nfs4_fs.h"
#include "nfs4idmap.h"
#include "dns_resolve.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 const struct super_operations nfs4_sops = {
.alloc_inode = nfs_alloc_inode,
.free_inode = nfs_free_inode,
.write_inode = nfs4_write_inode,
.drop_inode = nfs_drop_inode,
.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,
};
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)
ret = pnfs_layoutcommit_inode(inode,
wbc->sync_mode == WB_SYNC_ALL);
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_final(&inode->i_data);
clear_inode(inode);
/* If we are holding a delegation, return and free it */
nfs_inode_evict_delegation(inode);
/* Note that above delegreturn would trigger pnfs return-on-close */
pnfs_return_layout(inode);
pnfs_destroy_layout_final(NFS_I(inode));
/* First call standard NFS clear_inode() code */
nfs_clear_inode(inode);
nfs4_xattr_cache_zap(inode);
}
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 int do_nfs4_mount(struct nfs_server *server,
struct fs_context *fc,
const char *hostname,
const char *export_path)
{
struct nfs_fs_context *root_ctx;
struct nfs_fs_context *ctx;
struct fs_context *root_fc;
struct vfsmount *root_mnt;
struct dentry *dentry;
size_t len;
int ret;
struct fs_parameter param = {
.key = "source",
.type = fs_value_is_string,
.dirfd = -1,
};
struct fs_parameter param_fsc = {
.key = "fsc",
.type = fs_value_is_string,
.dirfd = -1,
};
if (IS_ERR(server))
return PTR_ERR(server);
root_fc = vfs_dup_fs_context(fc);
if (IS_ERR(root_fc)) {
nfs_free_server(server);
return PTR_ERR(root_fc);
}
kfree(root_fc->source);
root_fc->source = NULL;
ctx = nfs_fc2context(fc);
root_ctx = nfs_fc2context(root_fc);
root_ctx->internal = true;
root_ctx->server = server;
if (ctx->fscache_uniq) {
len = strlen(ctx->fscache_uniq);
param_fsc.size = len;
param_fsc.string = kmemdup_nul(ctx->fscache_uniq, len, GFP_KERNEL);
if (param_fsc.string == NULL) {
put_fs_context(root_fc);
return -ENOMEM;
}
ret = vfs_parse_fs_param(root_fc, &param_fsc);
kfree(param_fsc.string);
if (ret < 0) {
put_fs_context(root_fc);
return ret;
}
}
/* We leave export_path unset as it's not used to find the root. */
len = strlen(hostname) + 5;
param.string = kmalloc(len, GFP_KERNEL);
if (param.string == NULL) {
put_fs_context(root_fc);
return -ENOMEM;
}
/* Does hostname needs to be enclosed in brackets? */
if (strchr(hostname, ':'))
param.size = snprintf(param.string, len, "[%s]:/", hostname);
else
param.size = snprintf(param.string, len, "%s:/", hostname);
ret = vfs_parse_fs_param(root_fc, &param);
kfree(param.string);
if (ret < 0) {
put_fs_context(root_fc);
return ret;
}
root_mnt = fc_mount(root_fc);
put_fs_context(root_fc);
if (IS_ERR(root_mnt))
return PTR_ERR(root_mnt);
ret = nfs_referral_loop_protect();
if (ret) {
mntput(root_mnt);
return ret;
}
dentry = mount_subtree(root_mnt, export_path);
nfs_referral_loop_unprotect();
if (IS_ERR(dentry))
return PTR_ERR(dentry);
fc->root = dentry;
return 0;
}
int nfs4_try_get_tree(struct fs_context *fc)
{
struct nfs_fs_context *ctx = nfs_fc2context(fc);
int err;
dfprintk(MOUNT, "--> nfs4_try_get_tree()\n");
/* We create a mount for the server's root, walk to the requested
* location and then create another mount for that.
*/
err= do_nfs4_mount(nfs4_create_server(fc),
fc, ctx->nfs_server.hostname,
ctx->nfs_server.export_path);
if (err) {
nfs_ferrorf(fc, MOUNT, "NFS4: Couldn't follow remote path");
dfprintk(MOUNT, "<-- nfs4_try_get_tree() = %d [error]\n", err);
} else {
dfprintk(MOUNT, "<-- nfs4_try_get_tree() = 0\n");
}
return err;
}
/*
* Create an NFS4 server record on referral traversal
*/
int nfs4_get_referral_tree(struct fs_context *fc)
{
struct nfs_fs_context *ctx = nfs_fc2context(fc);
int err;
dprintk("--> nfs4_referral_mount()\n");
/* create a new volume representation */
err = do_nfs4_mount(nfs4_create_referral_server(fc),
fc, ctx->nfs_server.hostname,
ctx->nfs_server.export_path);
if (err) {
nfs_ferrorf(fc, MOUNT, "NFS4: Couldn't follow remote path");
dfprintk(MOUNT, "<-- nfs4_get_referral_tree() = %d [error]\n", err);
} else {
dfprintk(MOUNT, "<-- nfs4_get_referral_tree() = 0\n");
}
return err;
}
static int __init init_nfs_v4(void)
{
int err;
err = nfs_dns_resolver_init();
if (err)
goto out;
err = nfs_idmap_init();
if (err)
goto out1;
#ifdef CONFIG_NFS_V4_2
err = nfs4_xattr_cache_init();
if (err)
goto out2;
#endif
err = nfs4_register_sysctl();
if (err)
goto out2;
#ifdef CONFIG_NFS_V4_2
nfs42_ssc_register_ops();
#endif
register_nfs_version(&nfs_v4);
return 0;
out2:
nfs_idmap_quit();
out1:
nfs_dns_resolver_destroy();
out:
return err;
}
static void __exit exit_nfs_v4(void)
{
/* Not called in the _init(), conditionally loaded */
nfs4_pnfs_v3_ds_connect_unload();
unregister_nfs_version(&nfs_v4);
#ifdef CONFIG_NFS_V4_2
nfs4_xattr_cache_exit();
nfs42_ssc_unregister_ops();
#endif
nfs4_unregister_sysctl();
nfs_idmap_quit();
nfs_dns_resolver_destroy();
}
MODULE_LICENSE("GPL");
module_init(init_nfs_v4);
module_exit(exit_nfs_v4);