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export.c
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export.c
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#define MSNFS /* HACK HACK */
/*
* linux/fs/nfsd/export.c
*
* NFS exporting and validation.
*
* We maintain a list of clients, each of which has a list of
* exports. To export an fs to a given client, you first have
* to create the client entry with NFSCTL_ADDCLIENT, which
* creates a client control block and adds it to the hash
* table. Then, you call NFSCTL_EXPORT for each fs.
*
*
* Copyright (C) 1995, 1996 Olaf Kirch, <[email protected]>
*/
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/stat.h>
#include <linux/in.h>
#include <linux/seq_file.h>
#include <linux/syscalls.h>
#include <linux/rwsem.h>
#include <linux/dcache.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/hash.h>
#include <linux/module.h>
#include <linux/sunrpc/svc.h>
#include <linux/nfsd/nfsd.h>
#include <linux/nfsd/nfsfh.h>
#include <linux/nfsd/syscall.h>
#include <linux/lockd/bind.h>
#define NFSDDBG_FACILITY NFSDDBG_EXPORT
#define NFSD_PARANOIA 1
typedef struct auth_domain svc_client;
typedef struct svc_export svc_export;
static void exp_do_unexport(svc_export *unexp);
static int exp_verify_string(char *cp, int max);
/*
* We have two caches.
* One maps client+vfsmnt+dentry to export options - the export map
* The other maps client+filehandle-fragment to export options. - the expkey map
*
* The export options are actually stored in the first map, and the
* second map contains a reference to the entry in the first map.
*/
#define EXPKEY_HASHBITS 8
#define EXPKEY_HASHMAX (1 << EXPKEY_HASHBITS)
#define EXPKEY_HASHMASK (EXPKEY_HASHMAX -1)
static struct cache_head *expkey_table[EXPKEY_HASHMAX];
static inline int svc_expkey_hash(struct svc_expkey *item)
{
int hash = item->ek_fsidtype;
char * cp = (char*)item->ek_fsid;
int len = key_len(item->ek_fsidtype);
hash ^= hash_mem(cp, len, EXPKEY_HASHBITS);
hash ^= hash_ptr(item->ek_client, EXPKEY_HASHBITS);
return hash & EXPKEY_HASHMASK;
}
void expkey_put(struct cache_head *item, struct cache_detail *cd)
{
if (cache_put(item, cd)) {
struct svc_expkey *key = container_of(item, struct svc_expkey, h);
if (test_bit(CACHE_VALID, &item->flags) &&
!test_bit(CACHE_NEGATIVE, &item->flags))
exp_put(key->ek_export);
auth_domain_put(key->ek_client);
kfree(key);
}
}
static void expkey_request(struct cache_detail *cd,
struct cache_head *h,
char **bpp, int *blen)
{
/* client fsidtype \xfsid */
struct svc_expkey *ek = container_of(h, struct svc_expkey, h);
char type[5];
qword_add(bpp, blen, ek->ek_client->name);
snprintf(type, 5, "%d", ek->ek_fsidtype);
qword_add(bpp, blen, type);
qword_addhex(bpp, blen, (char*)ek->ek_fsid, key_len(ek->ek_fsidtype));
(*bpp)[-1] = '\n';
}
static struct svc_expkey *svc_expkey_lookup(struct svc_expkey *, int);
static int expkey_parse(struct cache_detail *cd, char *mesg, int mlen)
{
/* client fsidtype fsid [path] */
char *buf;
int len;
struct auth_domain *dom = NULL;
int err;
int fsidtype;
char *ep;
struct svc_expkey key;
if (mesg[mlen-1] != '\n')
return -EINVAL;
mesg[mlen-1] = 0;
buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
err = -ENOMEM;
if (!buf) goto out;
err = -EINVAL;
if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
goto out;
err = -ENOENT;
dom = auth_domain_find(buf);
if (!dom)
goto out;
dprintk("found domain %s\n", buf);
err = -EINVAL;
if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
goto out;
fsidtype = simple_strtoul(buf, &ep, 10);
if (*ep)
goto out;
dprintk("found fsidtype %d\n", fsidtype);
if (fsidtype > 2)
goto out;
if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
goto out;
dprintk("found fsid length %d\n", len);
if (len != key_len(fsidtype))
goto out;
/* OK, we seem to have a valid key */
key.h.flags = 0;
key.h.expiry_time = get_expiry(&mesg);
if (key.h.expiry_time == 0)
goto out;
key.ek_client = dom;
key.ek_fsidtype = fsidtype;
memcpy(key.ek_fsid, buf, len);
/* now we want a pathname, or empty meaning NEGATIVE */
if ((len=qword_get(&mesg, buf, PAGE_SIZE)) < 0)
goto out;
dprintk("Path seems to be <%s>\n", buf);
err = 0;
if (len == 0) {
struct svc_expkey *ek;
set_bit(CACHE_NEGATIVE, &key.h.flags);
ek = svc_expkey_lookup(&key, 1);
if (ek)
expkey_put(&ek->h, &svc_expkey_cache);
} else {
struct nameidata nd;
struct svc_expkey *ek;
struct svc_export *exp;
err = path_lookup(buf, 0, &nd);
if (err)
goto out;
dprintk("Found the path %s\n", buf);
exp = exp_get_by_name(dom, nd.mnt, nd.dentry, NULL);
err = -ENOENT;
if (!exp)
goto out_nd;
key.ek_export = exp;
dprintk("And found export\n");
ek = svc_expkey_lookup(&key, 1);
if (ek)
expkey_put(&ek->h, &svc_expkey_cache);
exp_put(exp);
err = 0;
out_nd:
path_release(&nd);
}
cache_flush();
out:
if (dom)
auth_domain_put(dom);
kfree(buf);
return err;
}
static int expkey_show(struct seq_file *m,
struct cache_detail *cd,
struct cache_head *h)
{
struct svc_expkey *ek ;
if (h ==NULL) {
seq_puts(m, "#domain fsidtype fsid [path]\n");
return 0;
}
ek = container_of(h, struct svc_expkey, h);
seq_printf(m, "%s %d 0x%08x", ek->ek_client->name,
ek->ek_fsidtype, ek->ek_fsid[0]);
if (ek->ek_fsidtype != 1)
seq_printf(m, "%08x", ek->ek_fsid[1]);
if (ek->ek_fsidtype == 2)
seq_printf(m, "%08x", ek->ek_fsid[2]);
if (test_bit(CACHE_VALID, &h->flags) &&
!test_bit(CACHE_NEGATIVE, &h->flags)) {
seq_printf(m, " ");
seq_path(m, ek->ek_export->ex_mnt, ek->ek_export->ex_dentry, "\\ \t\n");
}
seq_printf(m, "\n");
return 0;
}
struct cache_detail svc_expkey_cache = {
.owner = THIS_MODULE,
.hash_size = EXPKEY_HASHMAX,
.hash_table = expkey_table,
.name = "nfsd.fh",
.cache_put = expkey_put,
.cache_request = expkey_request,
.cache_parse = expkey_parse,
.cache_show = expkey_show,
};
static inline int svc_expkey_match (struct svc_expkey *a, struct svc_expkey *b)
{
if (a->ek_fsidtype != b->ek_fsidtype ||
a->ek_client != b->ek_client ||
memcmp(a->ek_fsid, b->ek_fsid, key_len(a->ek_fsidtype)) != 0)
return 0;
return 1;
}
static inline void svc_expkey_init(struct svc_expkey *new, struct svc_expkey *item)
{
cache_get(&item->ek_client->h);
new->ek_client = item->ek_client;
new->ek_fsidtype = item->ek_fsidtype;
new->ek_fsid[0] = item->ek_fsid[0];
new->ek_fsid[1] = item->ek_fsid[1];
new->ek_fsid[2] = item->ek_fsid[2];
}
static inline void svc_expkey_update(struct svc_expkey *new, struct svc_expkey *item)
{
cache_get(&item->ek_export->h);
new->ek_export = item->ek_export;
}
static DefineSimpleCacheLookup(svc_expkey,0) /* no inplace updates */
#define EXPORT_HASHBITS 8
#define EXPORT_HASHMAX (1<< EXPORT_HASHBITS)
#define EXPORT_HASHMASK (EXPORT_HASHMAX -1)
static struct cache_head *export_table[EXPORT_HASHMAX];
static inline int svc_export_hash(struct svc_export *item)
{
int rv;
rv = hash_ptr(item->ex_client, EXPORT_HASHBITS);
rv ^= hash_ptr(item->ex_dentry, EXPORT_HASHBITS);
rv ^= hash_ptr(item->ex_mnt, EXPORT_HASHBITS);
return rv;
}
void svc_export_put(struct cache_head *item, struct cache_detail *cd)
{
if (cache_put(item, cd)) {
struct svc_export *exp = container_of(item, struct svc_export, h);
dput(exp->ex_dentry);
mntput(exp->ex_mnt);
auth_domain_put(exp->ex_client);
kfree(exp);
}
}
static void svc_export_request(struct cache_detail *cd,
struct cache_head *h,
char **bpp, int *blen)
{
/* client path */
struct svc_export *exp = container_of(h, struct svc_export, h);
char *pth;
qword_add(bpp, blen, exp->ex_client->name);
pth = d_path(exp->ex_dentry, exp->ex_mnt, *bpp, *blen);
if (IS_ERR(pth)) {
/* is this correct? */
(*bpp)[0] = '\n';
return;
}
qword_add(bpp, blen, pth);
(*bpp)[-1] = '\n';
}
static struct svc_export *svc_export_lookup(struct svc_export *, int);
static int check_export(struct inode *inode, int flags)
{
/* We currently export only dirs and regular files.
* This is what umountd does.
*/
if (!S_ISDIR(inode->i_mode) &&
!S_ISREG(inode->i_mode))
return -ENOTDIR;
/* There are two requirements on a filesystem to be exportable.
* 1: We must be able to identify the filesystem from a number.
* either a device number (so FS_REQUIRES_DEV needed)
* or an FSID number (so NFSEXP_FSID needed).
* 2: We must be able to find an inode from a filehandle.
* This means that s_export_op must be set.
*/
if (!(inode->i_sb->s_type->fs_flags & FS_REQUIRES_DEV) &&
!(flags & NFSEXP_FSID)) {
dprintk("exp_export: export of non-dev fs without fsid");
return -EINVAL;
}
if (!inode->i_sb->s_export_op) {
dprintk("exp_export: export of invalid fs type.\n");
return -EINVAL;
}
/* Ok, we can export it */;
if (!inode->i_sb->s_export_op->find_exported_dentry)
inode->i_sb->s_export_op->find_exported_dentry =
find_exported_dentry;
return 0;
}
static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
{
/* client path expiry [flags anonuid anongid fsid] */
char *buf;
int len;
int err;
struct auth_domain *dom = NULL;
struct nameidata nd;
struct svc_export exp, *expp;
int an_int;
nd.dentry = NULL;
if (mesg[mlen-1] != '\n')
return -EINVAL;
mesg[mlen-1] = 0;
buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
err = -ENOMEM;
if (!buf) goto out;
/* client */
len = qword_get(&mesg, buf, PAGE_SIZE);
err = -EINVAL;
if (len <= 0) goto out;
err = -ENOENT;
dom = auth_domain_find(buf);
if (!dom)
goto out;
/* path */
err = -EINVAL;
if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
goto out;
err = path_lookup(buf, 0, &nd);
if (err) goto out;
exp.h.flags = 0;
exp.ex_client = dom;
exp.ex_mnt = nd.mnt;
exp.ex_dentry = nd.dentry;
/* expiry */
err = -EINVAL;
exp.h.expiry_time = get_expiry(&mesg);
if (exp.h.expiry_time == 0)
goto out;
/* flags */
err = get_int(&mesg, &an_int);
if (err == -ENOENT)
set_bit(CACHE_NEGATIVE, &exp.h.flags);
else {
if (err || an_int < 0) goto out;
exp.ex_flags= an_int;
/* anon uid */
err = get_int(&mesg, &an_int);
if (err) goto out;
exp.ex_anon_uid= an_int;
/* anon gid */
err = get_int(&mesg, &an_int);
if (err) goto out;
exp.ex_anon_gid= an_int;
/* fsid */
err = get_int(&mesg, &an_int);
if (err) goto out;
exp.ex_fsid = an_int;
err = check_export(nd.dentry->d_inode, exp.ex_flags);
if (err) goto out;
}
expp = svc_export_lookup(&exp, 1);
if (expp)
exp_put(expp);
err = 0;
cache_flush();
out:
if (nd.dentry)
path_release(&nd);
if (dom)
auth_domain_put(dom);
kfree(buf);
return err;
}
static void exp_flags(struct seq_file *m, int flag, int fsid, uid_t anonu, uid_t anong);
static int svc_export_show(struct seq_file *m,
struct cache_detail *cd,
struct cache_head *h)
{
struct svc_export *exp ;
if (h ==NULL) {
seq_puts(m, "#path domain(flags)\n");
return 0;
}
exp = container_of(h, struct svc_export, h);
seq_path(m, exp->ex_mnt, exp->ex_dentry, " \t\n\\");
seq_putc(m, '\t');
seq_escape(m, exp->ex_client->name, " \t\n\\");
seq_putc(m, '(');
if (test_bit(CACHE_VALID, &h->flags) &&
!test_bit(CACHE_NEGATIVE, &h->flags))
exp_flags(m, exp->ex_flags, exp->ex_fsid,
exp->ex_anon_uid, exp->ex_anon_gid);
seq_puts(m, ")\n");
return 0;
}
struct cache_detail svc_export_cache = {
.owner = THIS_MODULE,
.hash_size = EXPORT_HASHMAX,
.hash_table = export_table,
.name = "nfsd.export",
.cache_put = svc_export_put,
.cache_request = svc_export_request,
.cache_parse = svc_export_parse,
.cache_show = svc_export_show,
};
static inline int svc_export_match(struct svc_export *a, struct svc_export *b)
{
return a->ex_client == b->ex_client &&
a->ex_dentry == b->ex_dentry &&
a->ex_mnt == b->ex_mnt;
}
static inline void svc_export_init(struct svc_export *new, struct svc_export *item)
{
cache_get(&item->ex_client->h);
new->ex_client = item->ex_client;
new->ex_dentry = dget(item->ex_dentry);
new->ex_mnt = mntget(item->ex_mnt);
}
static inline void svc_export_update(struct svc_export *new, struct svc_export *item)
{
new->ex_flags = item->ex_flags;
new->ex_anon_uid = item->ex_anon_uid;
new->ex_anon_gid = item->ex_anon_gid;
new->ex_fsid = item->ex_fsid;
}
static DefineSimpleCacheLookup(svc_export,1) /* allow inplace updates */
struct svc_expkey *
exp_find_key(svc_client *clp, int fsid_type, u32 *fsidv, struct cache_req *reqp)
{
struct svc_expkey key, *ek;
int err;
if (!clp)
return NULL;
key.ek_client = clp;
key.ek_fsidtype = fsid_type;
memcpy(key.ek_fsid, fsidv, key_len(fsid_type));
ek = svc_expkey_lookup(&key, 0);
if (ek != NULL)
if ((err = cache_check(&svc_expkey_cache, &ek->h, reqp)))
ek = ERR_PTR(err);
return ek;
}
static int exp_set_key(svc_client *clp, int fsid_type, u32 *fsidv,
struct svc_export *exp)
{
struct svc_expkey key, *ek;
key.ek_client = clp;
key.ek_fsidtype = fsid_type;
memcpy(key.ek_fsid, fsidv, key_len(fsid_type));
key.ek_export = exp;
key.h.expiry_time = NEVER;
key.h.flags = 0;
ek = svc_expkey_lookup(&key, 1);
if (ek) {
expkey_put(&ek->h, &svc_expkey_cache);
return 0;
}
return -ENOMEM;
}
/*
* Find the client's export entry matching xdev/xino.
*/
static inline struct svc_expkey *
exp_get_key(svc_client *clp, dev_t dev, ino_t ino)
{
u32 fsidv[3];
if (old_valid_dev(dev)) {
mk_fsid_v0(fsidv, dev, ino);
return exp_find_key(clp, 0, fsidv, NULL);
}
mk_fsid_v3(fsidv, dev, ino);
return exp_find_key(clp, 3, fsidv, NULL);
}
/*
* Find the client's export entry matching fsid
*/
static inline struct svc_expkey *
exp_get_fsid_key(svc_client *clp, int fsid)
{
u32 fsidv[2];
mk_fsid_v1(fsidv, fsid);
return exp_find_key(clp, 1, fsidv, NULL);
}
svc_export *
exp_get_by_name(svc_client *clp, struct vfsmount *mnt, struct dentry *dentry,
struct cache_req *reqp)
{
struct svc_export *exp, key;
if (!clp)
return NULL;
key.ex_client = clp;
key.ex_mnt = mnt;
key.ex_dentry = dentry;
exp = svc_export_lookup(&key, 0);
if (exp != NULL)
switch (cache_check(&svc_export_cache, &exp->h, reqp)) {
case 0: break;
case -EAGAIN:
exp = ERR_PTR(-EAGAIN);
break;
default:
exp = NULL;
}
return exp;
}
/*
* Find the export entry for a given dentry.
*/
struct svc_export *
exp_parent(svc_client *clp, struct vfsmount *mnt, struct dentry *dentry,
struct cache_req *reqp)
{
svc_export *exp;
dget(dentry);
exp = exp_get_by_name(clp, mnt, dentry, reqp);
while (exp == NULL && !IS_ROOT(dentry)) {
struct dentry *parent;
parent = dget_parent(dentry);
dput(dentry);
dentry = parent;
exp = exp_get_by_name(clp, mnt, dentry, reqp);
}
dput(dentry);
return exp;
}
/*
* Hashtable locking. Write locks are placed only by user processes
* wanting to modify export information.
* Write locking only done in this file. Read locking
* needed externally.
*/
static DECLARE_RWSEM(hash_sem);
void
exp_readlock(void)
{
down_read(&hash_sem);
}
static inline void
exp_writelock(void)
{
down_write(&hash_sem);
}
void
exp_readunlock(void)
{
up_read(&hash_sem);
}
static inline void
exp_writeunlock(void)
{
up_write(&hash_sem);
}
static void exp_fsid_unhash(struct svc_export *exp)
{
struct svc_expkey *ek;
if ((exp->ex_flags & NFSEXP_FSID) == 0)
return;
ek = exp_get_fsid_key(exp->ex_client, exp->ex_fsid);
if (ek && !IS_ERR(ek)) {
ek->h.expiry_time = get_seconds()-1;
expkey_put(&ek->h, &svc_expkey_cache);
}
svc_expkey_cache.nextcheck = get_seconds();
}
static int exp_fsid_hash(svc_client *clp, struct svc_export *exp)
{
u32 fsid[2];
if ((exp->ex_flags & NFSEXP_FSID) == 0)
return 0;
mk_fsid_v1(fsid, exp->ex_fsid);
return exp_set_key(clp, 1, fsid, exp);
}
static int exp_hash(struct auth_domain *clp, struct svc_export *exp)
{
u32 fsid[2];
struct inode *inode = exp->ex_dentry->d_inode;
dev_t dev = inode->i_sb->s_dev;
if (old_valid_dev(dev)) {
mk_fsid_v0(fsid, dev, inode->i_ino);
return exp_set_key(clp, 0, fsid, exp);
}
mk_fsid_v3(fsid, dev, inode->i_ino);
return exp_set_key(clp, 3, fsid, exp);
}
static void exp_unhash(struct svc_export *exp)
{
struct svc_expkey *ek;
struct inode *inode = exp->ex_dentry->d_inode;
ek = exp_get_key(exp->ex_client, inode->i_sb->s_dev, inode->i_ino);
if (ek && !IS_ERR(ek)) {
ek->h.expiry_time = get_seconds()-1;
expkey_put(&ek->h, &svc_expkey_cache);
}
svc_expkey_cache.nextcheck = get_seconds();
}
/*
* Export a file system.
*/
int
exp_export(struct nfsctl_export *nxp)
{
svc_client *clp;
struct svc_export *exp = NULL;
struct svc_export new;
struct svc_expkey *fsid_key = NULL;
struct nameidata nd;
int err;
/* Consistency check */
err = -EINVAL;
if (!exp_verify_string(nxp->ex_path, NFS_MAXPATHLEN) ||
!exp_verify_string(nxp->ex_client, NFSCLNT_IDMAX))
goto out;
dprintk("exp_export called for %s:%s (%x/%ld fl %x).\n",
nxp->ex_client, nxp->ex_path,
(unsigned)nxp->ex_dev, (long)nxp->ex_ino,
nxp->ex_flags);
/* Try to lock the export table for update */
exp_writelock();
/* Look up client info */
if (!(clp = auth_domain_find(nxp->ex_client)))
goto out_unlock;
/* Look up the dentry */
err = path_lookup(nxp->ex_path, 0, &nd);
if (err)
goto out_unlock;
err = -EINVAL;
exp = exp_get_by_name(clp, nd.mnt, nd.dentry, NULL);
/* must make sure there won't be an ex_fsid clash */
if ((nxp->ex_flags & NFSEXP_FSID) &&
(fsid_key = exp_get_fsid_key(clp, nxp->ex_dev)) &&
!IS_ERR(fsid_key) &&
fsid_key->ek_export &&
fsid_key->ek_export != exp)
goto finish;
if (exp) {
/* just a flags/id/fsid update */
exp_fsid_unhash(exp);
exp->ex_flags = nxp->ex_flags;
exp->ex_anon_uid = nxp->ex_anon_uid;
exp->ex_anon_gid = nxp->ex_anon_gid;
exp->ex_fsid = nxp->ex_dev;
err = exp_fsid_hash(clp, exp);
goto finish;
}
err = check_export(nd.dentry->d_inode, nxp->ex_flags);
if (err) goto finish;
err = -ENOMEM;
dprintk("nfsd: creating export entry %p for client %p\n", exp, clp);
new.h.expiry_time = NEVER;
new.h.flags = 0;
new.ex_client = clp;
new.ex_mnt = nd.mnt;
new.ex_dentry = nd.dentry;
new.ex_flags = nxp->ex_flags;
new.ex_anon_uid = nxp->ex_anon_uid;
new.ex_anon_gid = nxp->ex_anon_gid;
new.ex_fsid = nxp->ex_dev;
exp = svc_export_lookup(&new, 1);
if (exp == NULL)
goto finish;
err = 0;
if (exp_hash(clp, exp) ||
exp_fsid_hash(clp, exp)) {
/* failed to create at least one index */
exp_do_unexport(exp);
cache_flush();
err = -ENOMEM;
}
finish:
if (exp)
exp_put(exp);
if (fsid_key && !IS_ERR(fsid_key))
expkey_put(&fsid_key->h, &svc_expkey_cache);
if (clp)
auth_domain_put(clp);
path_release(&nd);
out_unlock:
exp_writeunlock();
out:
return err;
}
/*
* Unexport a file system. The export entry has already
* been removed from the client's list of exported fs's.
*/
static void
exp_do_unexport(svc_export *unexp)
{
unexp->h.expiry_time = get_seconds()-1;
svc_export_cache.nextcheck = get_seconds();
exp_unhash(unexp);
exp_fsid_unhash(unexp);
}
/*
* unexport syscall.
*/
int
exp_unexport(struct nfsctl_export *nxp)
{
struct auth_domain *dom;
svc_export *exp;
struct nameidata nd;
int err;
/* Consistency check */
if (!exp_verify_string(nxp->ex_path, NFS_MAXPATHLEN) ||
!exp_verify_string(nxp->ex_client, NFSCLNT_IDMAX))
return -EINVAL;
exp_writelock();
err = -EINVAL;
dom = auth_domain_find(nxp->ex_client);
if (!dom) {
dprintk("nfsd: unexport couldn't find %s\n", nxp->ex_client);
goto out_unlock;
}
err = path_lookup(nxp->ex_path, 0, &nd);
if (err)
goto out_domain;
err = -EINVAL;
exp = exp_get_by_name(dom, nd.mnt, nd.dentry, NULL);
path_release(&nd);
if (!exp)
goto out_domain;
exp_do_unexport(exp);
exp_put(exp);
err = 0;
out_domain:
auth_domain_put(dom);
cache_flush();
out_unlock:
exp_writeunlock();
return err;
}
/*
* Obtain the root fh on behalf of a client.
* This could be done in user space, but I feel that it adds some safety
* since its harder to fool a kernel module than a user space program.
*/
int
exp_rootfh(svc_client *clp, char *path, struct knfsd_fh *f, int maxsize)
{
struct svc_export *exp;
struct nameidata nd;
struct inode *inode;
struct svc_fh fh;
int err;
err = -EPERM;
/* NB: we probably ought to check that it's NUL-terminated */
if (path_lookup(path, 0, &nd)) {
printk("nfsd: exp_rootfh path not found %s", path);
return err;
}
inode = nd.dentry->d_inode;
dprintk("nfsd: exp_rootfh(%s [%p] %s:%s/%ld)\n",
path, nd.dentry, clp->name,
inode->i_sb->s_id, inode->i_ino);
exp = exp_parent(clp, nd.mnt, nd.dentry, NULL);
if (!exp) {
dprintk("nfsd: exp_rootfh export not found.\n");
goto out;
}
/*
* fh must be initialized before calling fh_compose
*/
fh_init(&fh, maxsize);
if (fh_compose(&fh, exp, nd.dentry, NULL))
err = -EINVAL;
else
err = 0;
memcpy(f, &fh.fh_handle, sizeof(struct knfsd_fh));
fh_put(&fh);
exp_put(exp);
out:
path_release(&nd);
return err;
}
/*
* Called when we need the filehandle for the root of the pseudofs,
* for a given NFSv4 client. The root is defined to be the
* export point with fsid==0
*/
int
exp_pseudoroot(struct auth_domain *clp, struct svc_fh *fhp,
struct cache_req *creq)
{
struct svc_expkey *fsid_key;
int rv;
u32 fsidv[2];
mk_fsid_v1(fsidv, 0);
fsid_key = exp_find_key(clp, 1, fsidv, creq);
if (IS_ERR(fsid_key) && PTR_ERR(fsid_key) == -EAGAIN)
return nfserr_dropit;
if (!fsid_key || IS_ERR(fsid_key))
return nfserr_perm;
rv = fh_compose(fhp, fsid_key->ek_export,
fsid_key->ek_export->ex_dentry, NULL);
expkey_put(&fsid_key->h, &svc_expkey_cache);
return rv;
}
/* Iterator */
static void *e_start(struct seq_file *m, loff_t *pos)
{
loff_t n = *pos;
unsigned hash, export;
struct cache_head *ch;
exp_readlock();
read_lock(&svc_export_cache.hash_lock);
if (!n--)
return (void *)1;
hash = n >> 32;
export = n & ((1LL<<32) - 1);
for (ch=export_table[hash]; ch; ch=ch->next)
if (!export--)
return ch;
n &= ~((1LL<<32) - 1);
do {
hash++;
n += 1LL<<32;
} while(hash < EXPORT_HASHMAX && export_table[hash]==NULL);
if (hash >= EXPORT_HASHMAX)
return NULL;
*pos = n+1;
return export_table[hash];
}
static void *e_next(struct seq_file *m, void *p, loff_t *pos)
{
struct cache_head *ch = p;
int hash = (*pos >> 32);
if (p == (void *)1)
hash = 0;
else if (ch->next == NULL) {
hash++;
*pos += 1LL<<32;
} else {
++*pos;
return ch->next;
}
*pos &= ~((1LL<<32) - 1);
while (hash < EXPORT_HASHMAX && export_table[hash] == NULL) {
hash++;
*pos += 1LL<<32;
}
if (hash >= EXPORT_HASHMAX)
return NULL;
++*pos;
return export_table[hash];
}
static void e_stop(struct seq_file *m, void *p)
{
read_unlock(&svc_export_cache.hash_lock);
exp_readunlock();