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super.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/fs/nfs/super.c
*
* Copyright (C) 1992 Rick Sladkey
*
* nfs superblock handling functions
*
* Modularised by Alan Cox <[email protected]>, while hacking some
* experimental NFS changes. Modularisation taken straight from SYS5 fs.
*
* Change to nfs_read_super() to permit NFS mounts to multi-homed hosts.
*
* Split from inode.c by David Howells <[email protected]>
*
* - superblocks are indexed on server only - all inodes, dentries, etc. associated with a
* particular server are held in the same superblock
* - NFS superblocks can have several effective roots to the dentry tree
* - directory type roots are spliced into the tree when a path from one root reaches the root
* of another (see nfs_lookup())
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/time.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/unistd.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/addr.h>
#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/metrics.h>
#include <linux/sunrpc/xprtsock.h>
#include <linux/sunrpc/xprtrdma.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/nfs4_mount.h>
#include <linux/lockd/bind.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/vfs.h>
#include <linux/inet.h>
#include <linux/in6.h>
#include <linux/slab.h>
#include <net/ipv6.h>
#include <linux/netdevice.h>
#include <linux/nfs_xdr.h>
#include <linux/magic.h>
#include <linux/parser.h>
#include <linux/nsproxy.h>
#include <linux/rcupdate.h>
#include <linux/uaccess.h>
#include <linux/nfs_ssc.h>
#include "nfs4_fs.h"
#include "callback.h"
#include "delegation.h"
#include "iostat.h"
#include "internal.h"
#include "fscache.h"
#include "nfs4session.h"
#include "pnfs.h"
#include "nfs.h"
#define NFSDBG_FACILITY NFSDBG_VFS
const struct super_operations nfs_sops = {
.alloc_inode = nfs_alloc_inode,
.free_inode = nfs_free_inode,
.write_inode = nfs_write_inode,
.drop_inode = nfs_drop_inode,
.statfs = nfs_statfs,
.evict_inode = nfs_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,
};
EXPORT_SYMBOL_GPL(nfs_sops);
static const struct nfs_ssc_client_ops nfs_ssc_clnt_ops_tbl = {
.sco_sb_deactive = nfs_sb_deactive,
};
#if IS_ENABLED(CONFIG_NFS_V4)
static int __init register_nfs4_fs(void)
{
return register_filesystem(&nfs4_fs_type);
}
static void unregister_nfs4_fs(void)
{
unregister_filesystem(&nfs4_fs_type);
}
#else
static int __init register_nfs4_fs(void)
{
return 0;
}
static void unregister_nfs4_fs(void)
{
}
#endif
static void nfs_ssc_register_ops(void)
{
nfs_ssc_register(&nfs_ssc_clnt_ops_tbl);
}
static void nfs_ssc_unregister_ops(void)
{
nfs_ssc_unregister(&nfs_ssc_clnt_ops_tbl);
}
static struct shrinker acl_shrinker = {
.count_objects = nfs_access_cache_count,
.scan_objects = nfs_access_cache_scan,
.seeks = DEFAULT_SEEKS,
};
/*
* Register the NFS filesystems
*/
int __init register_nfs_fs(void)
{
int ret;
ret = register_filesystem(&nfs_fs_type);
if (ret < 0)
goto error_0;
ret = register_nfs4_fs();
if (ret < 0)
goto error_1;
ret = nfs_register_sysctl();
if (ret < 0)
goto error_2;
ret = register_shrinker(&acl_shrinker);
if (ret < 0)
goto error_3;
nfs_ssc_register_ops();
return 0;
error_3:
nfs_unregister_sysctl();
error_2:
unregister_nfs4_fs();
error_1:
unregister_filesystem(&nfs_fs_type);
error_0:
return ret;
}
/*
* Unregister the NFS filesystems
*/
void __exit unregister_nfs_fs(void)
{
unregister_shrinker(&acl_shrinker);
nfs_unregister_sysctl();
unregister_nfs4_fs();
nfs_ssc_unregister_ops();
unregister_filesystem(&nfs_fs_type);
}
bool nfs_sb_active(struct super_block *sb)
{
struct nfs_server *server = NFS_SB(sb);
if (!atomic_inc_not_zero(&sb->s_active))
return false;
if (atomic_inc_return(&server->active) != 1)
atomic_dec(&sb->s_active);
return true;
}
EXPORT_SYMBOL_GPL(nfs_sb_active);
void nfs_sb_deactive(struct super_block *sb)
{
struct nfs_server *server = NFS_SB(sb);
if (atomic_dec_and_test(&server->active))
deactivate_super(sb);
}
EXPORT_SYMBOL_GPL(nfs_sb_deactive);
static int __nfs_list_for_each_server(struct list_head *head,
int (*fn)(struct nfs_server *, void *),
void *data)
{
struct nfs_server *server, *last = NULL;
int ret = 0;
rcu_read_lock();
list_for_each_entry_rcu(server, head, client_link) {
if (!(server->super && nfs_sb_active(server->super)))
continue;
rcu_read_unlock();
if (last)
nfs_sb_deactive(last->super);
last = server;
ret = fn(server, data);
if (ret)
goto out;
rcu_read_lock();
}
rcu_read_unlock();
out:
if (last)
nfs_sb_deactive(last->super);
return ret;
}
int nfs_client_for_each_server(struct nfs_client *clp,
int (*fn)(struct nfs_server *, void *),
void *data)
{
return __nfs_list_for_each_server(&clp->cl_superblocks, fn, data);
}
EXPORT_SYMBOL_GPL(nfs_client_for_each_server);
/*
* Deliver file system statistics to userspace
*/
int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct nfs_server *server = NFS_SB(dentry->d_sb);
unsigned char blockbits;
unsigned long blockres;
struct nfs_fh *fh = NFS_FH(d_inode(dentry));
struct nfs_fsstat res;
int error = -ENOMEM;
res.fattr = nfs_alloc_fattr();
if (res.fattr == NULL)
goto out_err;
error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
if (unlikely(error == -ESTALE)) {
struct dentry *pd_dentry;
pd_dentry = dget_parent(dentry);
nfs_zap_caches(d_inode(pd_dentry));
dput(pd_dentry);
}
nfs_free_fattr(res.fattr);
if (error < 0)
goto out_err;
buf->f_type = NFS_SUPER_MAGIC;
/*
* Current versions of glibc do not correctly handle the
* case where f_frsize != f_bsize. Eventually we want to
* report the value of wtmult in this field.
*/
buf->f_frsize = dentry->d_sb->s_blocksize;
/*
* On most *nix systems, f_blocks, f_bfree, and f_bavail
* are reported in units of f_frsize. Linux hasn't had
* an f_frsize field in its statfs struct until recently,
* thus historically Linux's sys_statfs reports these
* fields in units of f_bsize.
*/
buf->f_bsize = dentry->d_sb->s_blocksize;
blockbits = dentry->d_sb->s_blocksize_bits;
blockres = (1 << blockbits) - 1;
buf->f_blocks = (res.tbytes + blockres) >> blockbits;
buf->f_bfree = (res.fbytes + blockres) >> blockbits;
buf->f_bavail = (res.abytes + blockres) >> blockbits;
buf->f_files = res.tfiles;
buf->f_ffree = res.afiles;
buf->f_namelen = server->namelen;
return 0;
out_err:
dprintk("%s: statfs error = %d\n", __func__, -error);
return error;
}
EXPORT_SYMBOL_GPL(nfs_statfs);
/*
* Map the security flavour number to a name
*/
static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
{
static const struct {
rpc_authflavor_t flavour;
const char *str;
} sec_flavours[NFS_AUTH_INFO_MAX_FLAVORS] = {
/* update NFS_AUTH_INFO_MAX_FLAVORS when this list changes! */
{ RPC_AUTH_NULL, "null" },
{ RPC_AUTH_UNIX, "sys" },
{ RPC_AUTH_GSS_KRB5, "krb5" },
{ RPC_AUTH_GSS_KRB5I, "krb5i" },
{ RPC_AUTH_GSS_KRB5P, "krb5p" },
{ RPC_AUTH_GSS_LKEY, "lkey" },
{ RPC_AUTH_GSS_LKEYI, "lkeyi" },
{ RPC_AUTH_GSS_LKEYP, "lkeyp" },
{ RPC_AUTH_GSS_SPKM, "spkm" },
{ RPC_AUTH_GSS_SPKMI, "spkmi" },
{ RPC_AUTH_GSS_SPKMP, "spkmp" },
{ UINT_MAX, "unknown" }
};
int i;
for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
if (sec_flavours[i].flavour == flavour)
break;
}
return sec_flavours[i].str;
}
static void nfs_show_mountd_netid(struct seq_file *m, struct nfs_server *nfss,
int showdefaults)
{
struct sockaddr *sap = (struct sockaddr *) &nfss->mountd_address;
char *proto = NULL;
switch (sap->sa_family) {
case AF_INET:
switch (nfss->mountd_protocol) {
case IPPROTO_UDP:
proto = RPCBIND_NETID_UDP;
break;
case IPPROTO_TCP:
proto = RPCBIND_NETID_TCP;
break;
}
break;
case AF_INET6:
switch (nfss->mountd_protocol) {
case IPPROTO_UDP:
proto = RPCBIND_NETID_UDP6;
break;
case IPPROTO_TCP:
proto = RPCBIND_NETID_TCP6;
break;
}
break;
}
if (proto || showdefaults)
seq_printf(m, ",mountproto=%s", proto ?: "auto");
}
static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
int showdefaults)
{
struct sockaddr *sap = (struct sockaddr *)&nfss->mountd_address;
if (nfss->flags & NFS_MOUNT_LEGACY_INTERFACE)
return;
switch (sap->sa_family) {
case AF_INET: {
struct sockaddr_in *sin = (struct sockaddr_in *)sap;
seq_printf(m, ",mountaddr=%pI4", &sin->sin_addr.s_addr);
break;
}
case AF_INET6: {
struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
seq_printf(m, ",mountaddr=%pI6c", &sin6->sin6_addr);
break;
}
default:
if (showdefaults)
seq_puts(m, ",mountaddr=unspecified");
}
if (nfss->mountd_version || showdefaults)
seq_printf(m, ",mountvers=%u", nfss->mountd_version);
if ((nfss->mountd_port &&
nfss->mountd_port != (unsigned short)NFS_UNSPEC_PORT) ||
showdefaults)
seq_printf(m, ",mountport=%u", nfss->mountd_port);
nfs_show_mountd_netid(m, nfss, showdefaults);
}
#if IS_ENABLED(CONFIG_NFS_V4)
static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
int showdefaults)
{
struct nfs_client *clp = nfss->nfs_client;
seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
}
#else
static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
int showdefaults)
{
}
#endif
static void nfs_show_nfs_version(struct seq_file *m,
unsigned int version,
unsigned int minorversion)
{
seq_printf(m, ",vers=%u", version);
if (version == 4)
seq_printf(m, ".%u", minorversion);
}
/*
* Describe the mount options in force on this server representation
*/
static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
int showdefaults)
{
static const struct proc_nfs_info {
int flag;
const char *str;
const char *nostr;
} nfs_info[] = {
{ NFS_MOUNT_SOFT, ",soft", "" },
{ NFS_MOUNT_SOFTERR, ",softerr", "" },
{ NFS_MOUNT_SOFTREVAL, ",softreval", "" },
{ NFS_MOUNT_POSIX, ",posix", "" },
{ NFS_MOUNT_NOCTO, ",nocto", "" },
{ NFS_MOUNT_NOAC, ",noac", "" },
{ NFS_MOUNT_NONLM, ",nolock", "" },
{ NFS_MOUNT_NOACL, ",noacl", "" },
{ NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
{ NFS_MOUNT_UNSHARED, ",nosharecache", "" },
{ NFS_MOUNT_NORESVPORT, ",noresvport", "" },
{ 0, NULL, NULL }
};
const struct proc_nfs_info *nfs_infop;
struct nfs_client *clp = nfss->nfs_client;
u32 version = clp->rpc_ops->version;
int local_flock, local_fcntl;
nfs_show_nfs_version(m, version, clp->cl_minorversion);
seq_printf(m, ",rsize=%u", nfss->rsize);
seq_printf(m, ",wsize=%u", nfss->wsize);
if (nfss->bsize != 0)
seq_printf(m, ",bsize=%u", nfss->bsize);
seq_printf(m, ",namlen=%u", nfss->namelen);
if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
if (!(nfss->flags & (NFS_MOUNT_SOFT|NFS_MOUNT_SOFTERR)))
seq_puts(m, ",hard");
for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
if (nfss->flags & nfs_infop->flag)
seq_puts(m, nfs_infop->str);
else
seq_puts(m, nfs_infop->nostr);
}
rcu_read_lock();
seq_printf(m, ",proto=%s",
rpc_peeraddr2str(nfss->client, RPC_DISPLAY_NETID));
rcu_read_unlock();
if (clp->cl_nconnect > 0)
seq_printf(m, ",nconnect=%u", clp->cl_nconnect);
if (version == 4) {
if (nfss->port != NFS_PORT)
seq_printf(m, ",port=%u", nfss->port);
} else
if (nfss->port)
seq_printf(m, ",port=%u", nfss->port);
seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
if (version != 4)
nfs_show_mountd_options(m, nfss, showdefaults);
else
nfs_show_nfsv4_options(m, nfss, showdefaults);
if (nfss->options & NFS_OPTION_FSCACHE)
seq_puts(m, ",fsc");
if (nfss->options & NFS_OPTION_MIGRATION)
seq_puts(m, ",migration");
if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) {
if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
seq_puts(m, ",lookupcache=none");
else
seq_puts(m, ",lookupcache=pos");
}
local_flock = nfss->flags & NFS_MOUNT_LOCAL_FLOCK;
local_fcntl = nfss->flags & NFS_MOUNT_LOCAL_FCNTL;
if (!local_flock && !local_fcntl)
seq_puts(m, ",local_lock=none");
else if (local_flock && local_fcntl)
seq_puts(m, ",local_lock=all");
else if (local_flock)
seq_puts(m, ",local_lock=flock");
else
seq_puts(m, ",local_lock=posix");
}
/*
* Describe the mount options on this VFS mountpoint
*/
int nfs_show_options(struct seq_file *m, struct dentry *root)
{
struct nfs_server *nfss = NFS_SB(root->d_sb);
nfs_show_mount_options(m, nfss, 0);
rcu_read_lock();
seq_printf(m, ",addr=%s",
rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
RPC_DISPLAY_ADDR));
rcu_read_unlock();
return 0;
}
EXPORT_SYMBOL_GPL(nfs_show_options);
#if IS_ENABLED(CONFIG_NFS_V4)
static void show_lease(struct seq_file *m, struct nfs_server *server)
{
struct nfs_client *clp = server->nfs_client;
unsigned long expire;
seq_printf(m, ",lease_time=%ld", clp->cl_lease_time / HZ);
expire = clp->cl_last_renewal + clp->cl_lease_time;
seq_printf(m, ",lease_expired=%ld",
time_after(expire, jiffies) ? 0 : (jiffies - expire) / HZ);
}
#ifdef CONFIG_NFS_V4_1
static void show_sessions(struct seq_file *m, struct nfs_server *server)
{
if (nfs4_has_session(server->nfs_client))
seq_puts(m, ",sessions");
}
#else
static void show_sessions(struct seq_file *m, struct nfs_server *server) {}
#endif
#endif
#ifdef CONFIG_NFS_V4_1
static void show_pnfs(struct seq_file *m, struct nfs_server *server)
{
seq_printf(m, ",pnfs=");
if (server->pnfs_curr_ld)
seq_printf(m, "%s", server->pnfs_curr_ld->name);
else
seq_printf(m, "not configured");
}
static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
{
if (nfss->nfs_client && nfss->nfs_client->cl_implid) {
struct nfs41_impl_id *impl_id = nfss->nfs_client->cl_implid;
seq_printf(m, "\n\timpl_id:\tname='%s',domain='%s',"
"date='%llu,%u'",
impl_id->name, impl_id->domain,
impl_id->date.seconds, impl_id->date.nseconds);
}
}
#else
#if IS_ENABLED(CONFIG_NFS_V4)
static void show_pnfs(struct seq_file *m, struct nfs_server *server)
{
}
#endif
static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
{
}
#endif
int nfs_show_devname(struct seq_file *m, struct dentry *root)
{
char *page = (char *) __get_free_page(GFP_KERNEL);
char *devname, *dummy;
int err = 0;
if (!page)
return -ENOMEM;
devname = nfs_path(&dummy, root, page, PAGE_SIZE, 0);
if (IS_ERR(devname))
err = PTR_ERR(devname);
else
seq_escape(m, devname, " \t\n\\");
free_page((unsigned long)page);
return err;
}
EXPORT_SYMBOL_GPL(nfs_show_devname);
int nfs_show_path(struct seq_file *m, struct dentry *dentry)
{
seq_puts(m, "/");
return 0;
}
EXPORT_SYMBOL_GPL(nfs_show_path);
/*
* Present statistical information for this VFS mountpoint
*/
int nfs_show_stats(struct seq_file *m, struct dentry *root)
{
int i, cpu;
struct nfs_server *nfss = NFS_SB(root->d_sb);
struct rpc_auth *auth = nfss->client->cl_auth;
struct nfs_iostats totals = { };
seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
/*
* Display all mount option settings
*/
seq_puts(m, "\n\topts:\t");
seq_puts(m, sb_rdonly(root->d_sb) ? "ro" : "rw");
seq_puts(m, root->d_sb->s_flags & SB_SYNCHRONOUS ? ",sync" : "");
seq_puts(m, root->d_sb->s_flags & SB_NOATIME ? ",noatime" : "");
seq_puts(m, root->d_sb->s_flags & SB_NODIRATIME ? ",nodiratime" : "");
nfs_show_mount_options(m, nfss, 1);
seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
show_implementation_id(m, nfss);
seq_puts(m, "\n\tcaps:\t");
seq_printf(m, "caps=0x%x", nfss->caps);
seq_printf(m, ",wtmult=%u", nfss->wtmult);
seq_printf(m, ",dtsize=%u", nfss->dtsize);
seq_printf(m, ",bsize=%u", nfss->bsize);
seq_printf(m, ",namlen=%u", nfss->namelen);
#if IS_ENABLED(CONFIG_NFS_V4)
if (nfss->nfs_client->rpc_ops->version == 4) {
seq_puts(m, "\n\tnfsv4:\t");
seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
seq_printf(m, ",bm2=0x%x", nfss->attr_bitmask[2]);
seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
show_sessions(m, nfss);
show_pnfs(m, nfss);
show_lease(m, nfss);
}
#endif
/*
* Display security flavor in effect for this mount
*/
seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
if (auth->au_flavor)
seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
/*
* Display superblock I/O counters
*/
for_each_possible_cpu(cpu) {
struct nfs_iostats *stats;
preempt_disable();
stats = per_cpu_ptr(nfss->io_stats, cpu);
for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
totals.events[i] += stats->events[i];
for (i = 0; i < __NFSIOS_BYTESMAX; i++)
totals.bytes[i] += stats->bytes[i];
#ifdef CONFIG_NFS_FSCACHE
for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
totals.fscache[i] += stats->fscache[i];
#endif
preempt_enable();
}
seq_puts(m, "\n\tevents:\t");
for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
seq_printf(m, "%lu ", totals.events[i]);
seq_puts(m, "\n\tbytes:\t");
for (i = 0; i < __NFSIOS_BYTESMAX; i++)
seq_printf(m, "%Lu ", totals.bytes[i]);
#ifdef CONFIG_NFS_FSCACHE
if (nfss->options & NFS_OPTION_FSCACHE) {
seq_puts(m, "\n\tfsc:\t");
for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
seq_printf(m, "%Lu ", totals.fscache[i]);
}
#endif
seq_putc(m, '\n');
rpc_clnt_show_stats(m, nfss->client);
return 0;
}
EXPORT_SYMBOL_GPL(nfs_show_stats);
/*
* Begin unmount by attempting to remove all automounted mountpoints we added
* in response to xdev traversals and referrals
*/
void nfs_umount_begin(struct super_block *sb)
{
struct nfs_server *server;
struct rpc_clnt *rpc;
server = NFS_SB(sb);
/* -EIO all pending I/O */
rpc = server->client_acl;
if (!IS_ERR(rpc))
rpc_killall_tasks(rpc);
rpc = server->client;
if (!IS_ERR(rpc))
rpc_killall_tasks(rpc);
}
EXPORT_SYMBOL_GPL(nfs_umount_begin);
/*
* Return true if 'match' is in auth_info or auth_info is empty.
* Return false otherwise.
*/
bool nfs_auth_info_match(const struct nfs_auth_info *auth_info,
rpc_authflavor_t match)
{
int i;
if (!auth_info->flavor_len)
return true;
for (i = 0; i < auth_info->flavor_len; i++) {
if (auth_info->flavors[i] == match)
return true;
}
return false;
}
EXPORT_SYMBOL_GPL(nfs_auth_info_match);
/*
* Ensure that a specified authtype in ctx->auth_info is supported by
* the server. Returns 0 and sets ctx->selected_flavor if it's ok, and
* -EACCES if not.
*/
static int nfs_verify_authflavors(struct nfs_fs_context *ctx,
rpc_authflavor_t *server_authlist,
unsigned int count)
{
rpc_authflavor_t flavor = RPC_AUTH_MAXFLAVOR;
bool found_auth_null = false;
unsigned int i;
/*
* If the sec= mount option is used, the specified flavor or AUTH_NULL
* must be in the list returned by the server.
*
* AUTH_NULL has a special meaning when it's in the server list - it
* means that the server will ignore the rpc creds, so any flavor
* can be used but still use the sec= that was specified.
*
* Note also that the MNT procedure in MNTv1 does not return a list
* of supported security flavors. In this case, nfs_mount() fabricates
* a security flavor list containing just AUTH_NULL.
*/
for (i = 0; i < count; i++) {
flavor = server_authlist[i];
if (nfs_auth_info_match(&ctx->auth_info, flavor))
goto out;
if (flavor == RPC_AUTH_NULL)
found_auth_null = true;
}
if (found_auth_null) {
flavor = ctx->auth_info.flavors[0];
goto out;
}
dfprintk(MOUNT,
"NFS: specified auth flavors not supported by server\n");
return -EACCES;
out:
ctx->selected_flavor = flavor;
dfprintk(MOUNT, "NFS: using auth flavor %u\n", ctx->selected_flavor);
return 0;
}
/*
* Use the remote server's MOUNT service to request the NFS file handle
* corresponding to the provided path.
*/
static int nfs_request_mount(struct fs_context *fc,
struct nfs_fh *root_fh,
rpc_authflavor_t *server_authlist,
unsigned int *server_authlist_len)
{
struct nfs_fs_context *ctx = nfs_fc2context(fc);
struct nfs_mount_request request = {
.sap = (struct sockaddr *)
&ctx->mount_server.address,
.dirpath = ctx->nfs_server.export_path,
.protocol = ctx->mount_server.protocol,
.fh = root_fh,
.noresvport = ctx->flags & NFS_MOUNT_NORESVPORT,
.auth_flav_len = server_authlist_len,
.auth_flavs = server_authlist,
.net = fc->net_ns,
};
int status;
if (ctx->mount_server.version == 0) {
switch (ctx->version) {
default:
ctx->mount_server.version = NFS_MNT3_VERSION;
break;
case 2:
ctx->mount_server.version = NFS_MNT_VERSION;
}
}
request.version = ctx->mount_server.version;
if (ctx->mount_server.hostname)
request.hostname = ctx->mount_server.hostname;
else
request.hostname = ctx->nfs_server.hostname;
/*
* Construct the mount server's address.
*/
if (ctx->mount_server.address.sa_family == AF_UNSPEC) {
memcpy(request.sap, &ctx->nfs_server.address,
ctx->nfs_server.addrlen);
ctx->mount_server.addrlen = ctx->nfs_server.addrlen;
}
request.salen = ctx->mount_server.addrlen;
nfs_set_port(request.sap, &ctx->mount_server.port, 0);
/*
* Now ask the mount server to map our export path
* to a file handle.
*/
status = nfs_mount(&request);
if (status != 0) {
dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
request.hostname, status);
return status;
}
return 0;
}
static struct nfs_server *nfs_try_mount_request(struct fs_context *fc)
{
struct nfs_fs_context *ctx = nfs_fc2context(fc);
int status;
unsigned int i;
bool tried_auth_unix = false;
bool auth_null_in_list = false;
struct nfs_server *server = ERR_PTR(-EACCES);
rpc_authflavor_t authlist[NFS_MAX_SECFLAVORS];
unsigned int authlist_len = ARRAY_SIZE(authlist);
status = nfs_request_mount(fc, ctx->mntfh, authlist, &authlist_len);
if (status)
return ERR_PTR(status);
/*
* Was a sec= authflavor specified in the options? First, verify
* whether the server supports it, and then just try to use it if so.
*/
if (ctx->auth_info.flavor_len > 0) {
status = nfs_verify_authflavors(ctx, authlist, authlist_len);
dfprintk(MOUNT, "NFS: using auth flavor %u\n",
ctx->selected_flavor);
if (status)
return ERR_PTR(status);
return ctx->nfs_mod->rpc_ops->create_server(fc);
}
/*
* No sec= option was provided. RFC 2623, section 2.7 suggests we
* SHOULD prefer the flavor listed first. However, some servers list
* AUTH_NULL first. Avoid ever choosing AUTH_NULL.
*/
for (i = 0; i < authlist_len; ++i) {
rpc_authflavor_t flavor;
struct rpcsec_gss_info info;
flavor = authlist[i];
switch (flavor) {
case RPC_AUTH_UNIX:
tried_auth_unix = true;
break;
case RPC_AUTH_NULL:
auth_null_in_list = true;
continue;
default:
if (rpcauth_get_gssinfo(flavor, &info) != 0)
continue;
/* Fallthrough */
}
dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
ctx->selected_flavor = flavor;
server = ctx->nfs_mod->rpc_ops->create_server(fc);
if (!IS_ERR(server))
return server;
}
/*
* Nothing we tried so far worked. At this point, give up if we've
* already tried AUTH_UNIX or if the server's list doesn't contain
* AUTH_NULL
*/
if (tried_auth_unix || !auth_null_in_list)
return server;
/* Last chance! Try AUTH_UNIX */
dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", RPC_AUTH_UNIX);
ctx->selected_flavor = RPC_AUTH_UNIX;
return ctx->nfs_mod->rpc_ops->create_server(fc);
}
int nfs_try_get_tree(struct fs_context *fc)
{
struct nfs_fs_context *ctx = nfs_fc2context(fc);
if (ctx->need_mount)
ctx->server = nfs_try_mount_request(fc);
else
ctx->server = ctx->nfs_mod->rpc_ops->create_server(fc);
return nfs_get_tree_common(fc);
}
EXPORT_SYMBOL_GPL(nfs_try_get_tree);
#define NFS_REMOUNT_CMP_FLAGMASK ~(NFS_MOUNT_INTR \
| NFS_MOUNT_SECURE \
| NFS_MOUNT_TCP \
| NFS_MOUNT_VER3 \
| NFS_MOUNT_KERBEROS \
| NFS_MOUNT_NONLM \
| NFS_MOUNT_BROKEN_SUID \
| NFS_MOUNT_STRICTLOCK \
| NFS_MOUNT_LEGACY_INTERFACE)
#define NFS_MOUNT_CMP_FLAGMASK (NFS_REMOUNT_CMP_FLAGMASK & \
~(NFS_MOUNT_UNSHARED | NFS_MOUNT_NORESVPORT))
static int
nfs_compare_remount_data(struct nfs_server *nfss,
struct nfs_fs_context *ctx)
{
if ((ctx->flags ^ nfss->flags) & NFS_REMOUNT_CMP_FLAGMASK ||
ctx->rsize != nfss->rsize ||
ctx->wsize != nfss->wsize ||
ctx->version != nfss->nfs_client->rpc_ops->version ||
ctx->minorversion != nfss->nfs_client->cl_minorversion ||
ctx->retrans != nfss->client->cl_timeout->to_retries ||
!nfs_auth_info_match(&ctx->auth_info, nfss->client->cl_auth->au_flavor) ||
ctx->acregmin != nfss->acregmin / HZ ||
ctx->acregmax != nfss->acregmax / HZ ||
ctx->acdirmin != nfss->acdirmin / HZ ||
ctx->acdirmax != nfss->acdirmax / HZ ||
ctx->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
(ctx->options & NFS_OPTION_FSCACHE) != (nfss->options & NFS_OPTION_FSCACHE) ||
ctx->nfs_server.port != nfss->port ||
ctx->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
!rpc_cmp_addr((struct sockaddr *)&ctx->nfs_server.address,
(struct sockaddr *)&nfss->nfs_client->cl_addr))
return -EINVAL;
return 0;
}
int nfs_reconfigure(struct fs_context *fc)
{
struct nfs_fs_context *ctx = nfs_fc2context(fc);
struct super_block *sb = fc->root->d_sb;
struct nfs_server *nfss = sb->s_fs_info;
sync_filesystem(sb);
/*
* Userspace mount programs that send binary options generally send
* them populated with default values. We have no way to know which
* ones were explicitly specified. Fall back to legacy behavior and
* just return success.
*/
if (ctx->skip_reconfig_option_check)
return 0;