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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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265 lines
6.3 KiB
C
265 lines
6.3 KiB
C
/*
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* linux/fs/nfs/nfs4namespace.c
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*
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* Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
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* - Modified by David Howells <dhowells@redhat.com>
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*
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* NFSv4 namespace
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*/
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#include <linux/dcache.h>
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#include <linux/mount.h>
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#include <linux/namei.h>
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#include <linux/nfs_fs.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <linux/sunrpc/clnt.h>
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#include <linux/vfs.h>
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#include <linux/inet.h>
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#include "internal.h"
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#include "nfs4_fs.h"
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#include "dns_resolve.h"
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#define NFSDBG_FACILITY NFSDBG_VFS
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/*
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* Convert the NFSv4 pathname components into a standard posix path.
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*
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* Note that the resulting string will be placed at the end of the buffer
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*/
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static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
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char *buffer, ssize_t buflen)
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{
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char *end = buffer + buflen;
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int n;
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*--end = '\0';
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buflen--;
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n = pathname->ncomponents;
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while (--n >= 0) {
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const struct nfs4_string *component = &pathname->components[n];
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buflen -= component->len + 1;
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if (buflen < 0)
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goto Elong;
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end -= component->len;
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memcpy(end, component->data, component->len);
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*--end = '/';
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}
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return end;
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Elong:
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return ERR_PTR(-ENAMETOOLONG);
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}
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/*
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* Determine the mount path as a string
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*/
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static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
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{
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char *limit;
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char *path = nfs_path(&limit, dentry, buffer, buflen);
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if (!IS_ERR(path)) {
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char *colon = strchr(path, ':');
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if (colon && colon < limit)
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path = colon + 1;
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}
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return path;
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}
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/*
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* Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
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* believe to be the server path to this dentry
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*/
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static int nfs4_validate_fspath(struct dentry *dentry,
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const struct nfs4_fs_locations *locations,
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char *page, char *page2)
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{
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const char *path, *fs_path;
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path = nfs4_path(dentry, page, PAGE_SIZE);
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if (IS_ERR(path))
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return PTR_ERR(path);
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fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
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if (IS_ERR(fs_path))
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return PTR_ERR(fs_path);
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if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
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dprintk("%s: path %s does not begin with fsroot %s\n",
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__func__, path, fs_path);
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return -ENOENT;
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}
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return 0;
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}
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static size_t nfs_parse_server_name(char *string, size_t len,
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struct sockaddr *sa, size_t salen)
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{
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ssize_t ret;
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ret = rpc_pton(string, len, sa, salen);
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if (ret == 0) {
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ret = nfs_dns_resolve_name(string, len, sa, salen);
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if (ret < 0)
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ret = 0;
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}
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return ret;
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}
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static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
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char *page, char *page2,
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const struct nfs4_fs_location *location)
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{
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const size_t addr_bufsize = sizeof(struct sockaddr_storage);
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struct vfsmount *mnt = ERR_PTR(-ENOENT);
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char *mnt_path;
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unsigned int maxbuflen;
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unsigned int s;
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mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
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if (IS_ERR(mnt_path))
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return ERR_CAST(mnt_path);
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mountdata->mnt_path = mnt_path;
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maxbuflen = mnt_path - 1 - page2;
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mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
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if (mountdata->addr == NULL)
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return ERR_PTR(-ENOMEM);
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for (s = 0; s < location->nservers; s++) {
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const struct nfs4_string *buf = &location->servers[s];
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if (buf->len <= 0 || buf->len >= maxbuflen)
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continue;
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if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
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continue;
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mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
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mountdata->addr, addr_bufsize);
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if (mountdata->addrlen == 0)
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continue;
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rpc_set_port(mountdata->addr, NFS_PORT);
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memcpy(page2, buf->data, buf->len);
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page2[buf->len] = '\0';
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mountdata->hostname = page2;
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snprintf(page, PAGE_SIZE, "%s:%s",
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mountdata->hostname,
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mountdata->mnt_path);
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mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata);
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if (!IS_ERR(mnt))
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break;
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}
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kfree(mountdata->addr);
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return mnt;
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}
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/**
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* nfs_follow_referral - set up mountpoint when hitting a referral on moved error
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* @dentry - parent directory
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* @locations - array of NFSv4 server location information
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*
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*/
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static struct vfsmount *nfs_follow_referral(struct dentry *dentry,
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const struct nfs4_fs_locations *locations)
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{
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struct vfsmount *mnt = ERR_PTR(-ENOENT);
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struct nfs_clone_mount mountdata = {
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.sb = dentry->d_sb,
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.dentry = dentry,
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.authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
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};
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char *page = NULL, *page2 = NULL;
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int loc, error;
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if (locations == NULL || locations->nlocations <= 0)
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goto out;
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dprintk("%s: referral at %s/%s\n", __func__,
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dentry->d_parent->d_name.name, dentry->d_name.name);
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page = (char *) __get_free_page(GFP_USER);
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if (!page)
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goto out;
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page2 = (char *) __get_free_page(GFP_USER);
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if (!page2)
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goto out;
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/* Ensure fs path is a prefix of current dentry path */
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error = nfs4_validate_fspath(dentry, locations, page, page2);
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if (error < 0) {
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mnt = ERR_PTR(error);
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goto out;
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}
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for (loc = 0; loc < locations->nlocations; loc++) {
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const struct nfs4_fs_location *location = &locations->locations[loc];
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if (location == NULL || location->nservers <= 0 ||
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location->rootpath.ncomponents == 0)
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continue;
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mnt = try_location(&mountdata, page, page2, location);
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if (!IS_ERR(mnt))
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break;
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}
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out:
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free_page((unsigned long) page);
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free_page((unsigned long) page2);
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dprintk("%s: done\n", __func__);
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return mnt;
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}
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/*
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* nfs_do_refmount - handle crossing a referral on server
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* @dentry - dentry of referral
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*
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*/
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struct vfsmount *nfs_do_refmount(struct dentry *dentry)
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{
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struct vfsmount *mnt = ERR_PTR(-ENOMEM);
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struct dentry *parent;
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struct nfs4_fs_locations *fs_locations = NULL;
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struct page *page;
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int err;
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/* BUG_ON(IS_ROOT(dentry)); */
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dprintk("%s: enter\n", __func__);
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page = alloc_page(GFP_KERNEL);
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if (page == NULL)
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goto out;
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fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
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if (fs_locations == NULL)
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goto out_free;
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/* Get locations */
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mnt = ERR_PTR(-ENOENT);
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parent = dget_parent(dentry);
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dprintk("%s: getting locations for %s/%s\n",
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__func__, parent->d_name.name, dentry->d_name.name);
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err = nfs4_proc_fs_locations(parent->d_inode, &dentry->d_name, fs_locations, page);
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dput(parent);
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if (err != 0 ||
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fs_locations->nlocations <= 0 ||
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fs_locations->fs_path.ncomponents <= 0)
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goto out_free;
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mnt = nfs_follow_referral(dentry, fs_locations);
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out_free:
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__free_page(page);
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kfree(fs_locations);
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out:
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dprintk("%s: done\n", __func__);
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return mnt;
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}
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