300 lines
6.6 KiB
C
300 lines
6.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2012 Bryan Schumaker <bjschuma@netapp.com>
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/mount.h>
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#include <linux/nfs4_mount.h>
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#include <linux/nfs_fs.h>
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#include "delegation.h"
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#include "internal.h"
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#include "nfs4_fs.h"
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#include "nfs4idmap.h"
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#include "dns_resolve.h"
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#include "pnfs.h"
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#include "nfs.h"
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#define NFSDBG_FACILITY NFSDBG_VFS
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static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc);
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static void nfs4_evict_inode(struct inode *inode);
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static const struct super_operations nfs4_sops = {
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.alloc_inode = nfs_alloc_inode,
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.free_inode = nfs_free_inode,
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.write_inode = nfs4_write_inode,
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.drop_inode = nfs_drop_inode,
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.statfs = nfs_statfs,
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.evict_inode = nfs4_evict_inode,
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.umount_begin = nfs_umount_begin,
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.show_options = nfs_show_options,
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.show_devname = nfs_show_devname,
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.show_path = nfs_show_path,
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.show_stats = nfs_show_stats,
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};
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struct nfs_subversion nfs_v4 = {
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.owner = THIS_MODULE,
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.nfs_fs = &nfs4_fs_type,
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.rpc_vers = &nfs_version4,
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.rpc_ops = &nfs_v4_clientops,
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.sops = &nfs4_sops,
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.xattr = nfs4_xattr_handlers,
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};
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static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc)
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{
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int ret = nfs_write_inode(inode, wbc);
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if (ret == 0)
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ret = pnfs_layoutcommit_inode(inode,
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wbc->sync_mode == WB_SYNC_ALL);
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return ret;
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}
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/*
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* Clean out any remaining NFSv4 state that might be left over due
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* to open() calls that passed nfs_atomic_lookup, but failed to call
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* nfs_open().
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*/
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static void nfs4_evict_inode(struct inode *inode)
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{
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truncate_inode_pages_final(&inode->i_data);
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clear_inode(inode);
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/* If we are holding a delegation, return and free it */
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nfs_inode_evict_delegation(inode);
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/* Note that above delegreturn would trigger pnfs return-on-close */
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pnfs_return_layout(inode);
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pnfs_destroy_layout(NFS_I(inode));
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/* First call standard NFS clear_inode() code */
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nfs_clear_inode(inode);
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}
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struct nfs_referral_count {
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struct list_head list;
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const struct task_struct *task;
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unsigned int referral_count;
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};
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static LIST_HEAD(nfs_referral_count_list);
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static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
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static struct nfs_referral_count *nfs_find_referral_count(void)
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{
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struct nfs_referral_count *p;
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list_for_each_entry(p, &nfs_referral_count_list, list) {
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if (p->task == current)
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return p;
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}
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return NULL;
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}
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#define NFS_MAX_NESTED_REFERRALS 2
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static int nfs_referral_loop_protect(void)
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{
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struct nfs_referral_count *p, *new;
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int ret = -ENOMEM;
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new = kmalloc(sizeof(*new), GFP_KERNEL);
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if (!new)
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goto out;
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new->task = current;
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new->referral_count = 1;
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ret = 0;
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spin_lock(&nfs_referral_count_list_lock);
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p = nfs_find_referral_count();
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if (p != NULL) {
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if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
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ret = -ELOOP;
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else
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p->referral_count++;
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} else {
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list_add(&new->list, &nfs_referral_count_list);
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new = NULL;
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}
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spin_unlock(&nfs_referral_count_list_lock);
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kfree(new);
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out:
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return ret;
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}
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static void nfs_referral_loop_unprotect(void)
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{
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struct nfs_referral_count *p;
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spin_lock(&nfs_referral_count_list_lock);
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p = nfs_find_referral_count();
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p->referral_count--;
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if (p->referral_count == 0)
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list_del(&p->list);
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else
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p = NULL;
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spin_unlock(&nfs_referral_count_list_lock);
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kfree(p);
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}
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static int do_nfs4_mount(struct nfs_server *server,
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struct fs_context *fc,
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const char *hostname,
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const char *export_path)
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{
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struct nfs_fs_context *root_ctx;
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struct fs_context *root_fc;
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struct vfsmount *root_mnt;
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struct dentry *dentry;
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size_t len;
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int ret;
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struct fs_parameter param = {
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.key = "source",
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.type = fs_value_is_string,
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.dirfd = -1,
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};
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if (IS_ERR(server))
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return PTR_ERR(server);
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root_fc = vfs_dup_fs_context(fc);
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if (IS_ERR(root_fc)) {
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nfs_free_server(server);
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return PTR_ERR(root_fc);
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}
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kfree(root_fc->source);
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root_fc->source = NULL;
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root_ctx = nfs_fc2context(root_fc);
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root_ctx->internal = true;
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root_ctx->server = server;
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/* We leave export_path unset as it's not used to find the root. */
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len = strlen(hostname) + 5;
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param.string = kmalloc(len, GFP_KERNEL);
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if (param.string == NULL) {
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put_fs_context(root_fc);
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return -ENOMEM;
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}
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/* Does hostname needs to be enclosed in brackets? */
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if (strchr(hostname, ':'))
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param.size = snprintf(param.string, len, "[%s]:/", hostname);
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else
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param.size = snprintf(param.string, len, "%s:/", hostname);
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ret = vfs_parse_fs_param(root_fc, ¶m);
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kfree(param.string);
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if (ret < 0) {
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put_fs_context(root_fc);
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return ret;
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}
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root_mnt = fc_mount(root_fc);
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put_fs_context(root_fc);
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if (IS_ERR(root_mnt))
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return PTR_ERR(root_mnt);
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ret = nfs_referral_loop_protect();
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if (ret) {
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mntput(root_mnt);
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return ret;
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}
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dentry = mount_subtree(root_mnt, export_path);
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nfs_referral_loop_unprotect();
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if (IS_ERR(dentry))
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return PTR_ERR(dentry);
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fc->root = dentry;
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return 0;
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}
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int nfs4_try_get_tree(struct fs_context *fc)
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{
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struct nfs_fs_context *ctx = nfs_fc2context(fc);
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int err;
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dfprintk(MOUNT, "--> nfs4_try_get_tree()\n");
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/* We create a mount for the server's root, walk to the requested
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* location and then create another mount for that.
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*/
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err= do_nfs4_mount(nfs4_create_server(fc),
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fc, ctx->nfs_server.hostname,
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ctx->nfs_server.export_path);
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if (err) {
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nfs_errorf(fc, "NFS4: Couldn't follow remote path");
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dfprintk(MOUNT, "<-- nfs4_try_get_tree() = %d [error]\n", err);
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} else {
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dfprintk(MOUNT, "<-- nfs4_try_get_tree() = 0\n");
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}
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return err;
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}
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/*
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* Create an NFS4 server record on referral traversal
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*/
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int nfs4_get_referral_tree(struct fs_context *fc)
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{
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struct nfs_fs_context *ctx = nfs_fc2context(fc);
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int err;
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dprintk("--> nfs4_referral_mount()\n");
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/* create a new volume representation */
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err = do_nfs4_mount(nfs4_create_referral_server(fc),
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fc, ctx->nfs_server.hostname,
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ctx->nfs_server.export_path);
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if (err) {
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nfs_errorf(fc, "NFS4: Couldn't follow remote path");
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dfprintk(MOUNT, "<-- nfs4_get_referral_tree() = %d [error]\n", err);
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} else {
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dfprintk(MOUNT, "<-- nfs4_get_referral_tree() = 0\n");
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}
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return err;
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}
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static int __init init_nfs_v4(void)
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{
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int err;
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err = nfs_dns_resolver_init();
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if (err)
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goto out;
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err = nfs_idmap_init();
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if (err)
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goto out1;
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err = nfs4_register_sysctl();
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if (err)
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goto out2;
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register_nfs_version(&nfs_v4);
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return 0;
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out2:
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nfs_idmap_quit();
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out1:
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nfs_dns_resolver_destroy();
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out:
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return err;
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}
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static void __exit exit_nfs_v4(void)
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{
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/* Not called in the _init(), conditionally loaded */
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nfs4_pnfs_v3_ds_connect_unload();
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unregister_nfs_version(&nfs_v4);
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nfs4_unregister_sysctl();
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nfs_idmap_quit();
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nfs_dns_resolver_destroy();
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}
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MODULE_LICENSE("GPL");
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module_init(init_nfs_v4);
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module_exit(exit_nfs_v4);
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