/*

   * 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, <okir@monad.swb.de>
   */

  #include <linux/slab.h>

  #include <linux/namei.h>

  #include <linux/module.h>

  #include <linux/exportfs.h>

  #include <net/ipv6.h>

  #include "nfsd.h"

  #include "nfsfh.h"

  #define NFSDDBG_FACILITY	NFSDDBG_EXPORT

  
  typedef struct auth_domain	svc_client;
  typedef struct svc_export	svc_export;

  /*
   * 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 void expkey_put(struct kref *ref)

  {

  	struct svc_expkey *key = container_of(ref, struct svc_expkey, h.ref);
  
  	if (test_bit(CACHE_VALID, &key->h.flags) &&

  	    !test_bit(CACHE_NEGATIVE, &key->h.flags))
  		path_put(&key->ek_path);

  	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] = '
  ';
  }

  static int expkey_upcall(struct cache_detail *cd, struct cache_head *h)
  {
  	return sunrpc_cache_pipe_upcall(cd, h, expkey_request);
  }

  static struct svc_expkey *svc_expkey_update(struct svc_expkey *new, struct svc_expkey *old);
  static struct svc_expkey *svc_expkey_lookup(struct svc_expkey *);

  static struct cache_detail svc_expkey_cache;

  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;

  	struct svc_expkey *ek = NULL;

  
  	if (mesg[mlen-1] != '
  ')
  		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
  ", 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
  ", fsidtype);

  	if (key_len(fsidtype)==0) /* invalid type */

  		goto out;
  	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
  		goto out;
  	dprintk("found fsid length %d
  ", 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);

  	ek = svc_expkey_lookup(&key);
  	err = -ENOMEM;
  	if (!ek)
  		goto out;

  	/* now we want a pathname, or empty meaning NEGATIVE  */

  	err = -EINVAL;

  	len = qword_get(&mesg, buf, PAGE_SIZE);
  	if (len < 0)

  		goto out;
  	dprintk("Path seems to be <%s>
  ", buf);
  	err = 0;
  	if (len == 0) {

  		set_bit(CACHE_NEGATIVE, &key.h.flags);

  		ek = svc_expkey_update(&key, ek);

  		if (!ek)
  			err = -ENOMEM;

  	} else {

  		err = kern_path(buf, 0, &key.ek_path);

  		if (err)

  			goto out;
  
  		dprintk("Found the path %s
  ", buf);

  		ek = svc_expkey_update(&key, ek);

  		if (!ek)

  			err = -ENOMEM;

  		path_put(&key.ek_path);

  	}
  	cache_flush();
   out:

  	if (ek)
  		cache_put(&ek->h, &svc_expkey_cache);

  	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 ;

  	int i;

  
  	if (h ==NULL) {
  		seq_puts(m, "#domain fsidtype fsid [path]
  ");
  		return 0;
  	}
  	ek = container_of(h, struct svc_expkey, h);

  	seq_printf(m, "%s %d 0x", ek->ek_client->name,
  		   ek->ek_fsidtype);
  	for (i=0; i < key_len(ek->ek_fsidtype)/4; i++)
  		seq_printf(m, "%08x", ek->ek_fsid[i]);

  	if (test_bit(CACHE_VALID, &h->flags) && 
  	    !test_bit(CACHE_NEGATIVE, &h->flags)) {
  		seq_printf(m, " ");

  		seq_path(m, &ek->ek_path, "\\ \t
  ");

  	}
  	seq_printf(m, "
  ");
  	return 0;
  }

  static inline int expkey_match (struct cache_head *a, struct cache_head *b)

  {

  	struct svc_expkey *orig = container_of(a, struct svc_expkey, h);
  	struct svc_expkey *new = container_of(b, struct svc_expkey, h);
  
  	if (orig->ek_fsidtype != new->ek_fsidtype ||
  	    orig->ek_client != new->ek_client ||
  	    memcmp(orig->ek_fsid, new->ek_fsid, key_len(orig->ek_fsidtype)) != 0)

  		return 0;
  	return 1;
  }

  static inline void expkey_init(struct cache_head *cnew,
  				   struct cache_head *citem)

  {

  	struct svc_expkey *new = container_of(cnew, struct svc_expkey, h);
  	struct svc_expkey *item = container_of(citem, struct svc_expkey, h);

  	kref_get(&item->ek_client->ref);

  	new->ek_client = item->ek_client;
  	new->ek_fsidtype = item->ek_fsidtype;

  
  	memcpy(new->ek_fsid, item->ek_fsid, sizeof(new->ek_fsid));

  }

  static inline void expkey_update(struct cache_head *cnew,
  				   struct cache_head *citem)

  {

  	struct svc_expkey *new = container_of(cnew, struct svc_expkey, h);
  	struct svc_expkey *item = container_of(citem, struct svc_expkey, h);

  	new->ek_path = item->ek_path;
  	path_get(&item->ek_path);

  }

  static struct cache_head *expkey_alloc(void)
  {
  	struct svc_expkey *i = kmalloc(sizeof(*i), GFP_KERNEL);
  	if (i)
  		return &i->h;
  	else
  		return NULL;
  }

  static 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_upcall	= expkey_upcall,

  	.cache_parse	= expkey_parse,
  	.cache_show	= expkey_show,
  	.match		= expkey_match,
  	.init		= expkey_init,
  	.update       	= expkey_update,
  	.alloc		= expkey_alloc,
  };

  static 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);
  	hash &= EXPKEY_HASHMASK;

  	return hash;
  }
  
  static struct svc_expkey *
  svc_expkey_lookup(struct svc_expkey *item)
  {
  	struct cache_head *ch;
  	int hash = svc_expkey_hash(item);

  
  	ch = sunrpc_cache_lookup(&svc_expkey_cache, &item->h,
  				 hash);
  	if (ch)
  		return container_of(ch, struct svc_expkey, h);
  	else
  		return NULL;
  }
  
  static struct svc_expkey *
  svc_expkey_update(struct svc_expkey *new, struct svc_expkey *old)
  {
  	struct cache_head *ch;

  	int hash = svc_expkey_hash(new);

  
  	ch = sunrpc_cache_update(&svc_expkey_cache, &new->h,
  				 &old->h, hash);
  	if (ch)
  		return container_of(ch, struct svc_expkey, h);
  	else
  		return NULL;
  }

  
  #define	EXPORT_HASHBITS		8
  #define	EXPORT_HASHMAX		(1<< EXPORT_HASHBITS)

  
  static struct cache_head *export_table[EXPORT_HASHMAX];

  static void nfsd4_fslocs_free(struct nfsd4_fs_locations *fsloc)
  {
  	int i;
  
  	for (i = 0; i < fsloc->locations_count; i++) {
  		kfree(fsloc->locations[i].path);
  		kfree(fsloc->locations[i].hosts);
  	}
  	kfree(fsloc->locations);
  }

  static void svc_export_put(struct kref *ref)

  {

  	struct svc_export *exp = container_of(ref, struct svc_export, h.ref);

  	path_put(&exp->ex_path);

  	auth_domain_put(exp->ex_client);

  	nfsd4_fslocs_free(&exp->ex_fslocs);

  	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_path, *bpp, *blen);

  	if (IS_ERR(pth)) {
  		/* is this correct? */
  		(*bpp)[0] = '
  ';
  		return;
  	}
  	qword_add(bpp, blen, pth);
  	(*bpp)[-1] = '
  ';
  }

  static int svc_export_upcall(struct cache_detail *cd, struct cache_head *h)
  {
  	return sunrpc_cache_pipe_upcall(cd, h, svc_export_request);
  }

  static struct svc_export *svc_export_update(struct svc_export *new,
  					    struct svc_export *old);

  static struct svc_export *svc_export_lookup(struct svc_export *);

  static int check_export(struct inode *inode, int *flags, unsigned char *uuid)

  {

  	/*
  	 * We currently export only dirs, regular files, and (for v4
  	 * pseudoroot) symlinks.

  	 */
  	if (!S_ISDIR(inode->i_mode) &&

  	    !S_ISLNK(inode->i_mode) &&

  	    !S_ISREG(inode->i_mode))
  		return -ENOTDIR;

  	/*
  	 * Mountd should never pass down a writeable V4ROOT export, but,
  	 * just to make sure:
  	 */
  	if (*flags & NFSEXP_V4ROOT)
  		*flags |= NFSEXP_READONLY;

  	/* 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 or ->uuid is 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) &&

  	    uuid == NULL) {

  		dprintk("exp_export: export of non-dev fs without fsid
  ");

  		return -EINVAL;
  	}

  
  	if (!inode->i_sb->s_export_op ||
  	    !inode->i_sb->s_export_op->fh_to_dentry) {

  		dprintk("exp_export: export of invalid fs type.
  ");
  		return -EINVAL;
  	}

  	return 0;
  
  }

  #ifdef CONFIG_NFSD_V4
  
  static int
  fsloc_parse(char **mesg, char *buf, struct nfsd4_fs_locations *fsloc)
  {
  	int len;
  	int migrated, i, err;

  	/* listsize */
  	err = get_int(mesg, &fsloc->locations_count);
  	if (err)
  		return err;
  	if (fsloc->locations_count > MAX_FS_LOCATIONS)
  		return -EINVAL;
  	if (fsloc->locations_count == 0)
  		return 0;
  
  	fsloc->locations = kzalloc(fsloc->locations_count
  			* sizeof(struct nfsd4_fs_location), GFP_KERNEL);
  	if (!fsloc->locations)
  		return -ENOMEM;
  	for (i=0; i < fsloc->locations_count; i++) {
  		/* colon separated host list */
  		err = -EINVAL;
  		len = qword_get(mesg, buf, PAGE_SIZE);
  		if (len <= 0)
  			goto out_free_all;
  		err = -ENOMEM;
  		fsloc->locations[i].hosts = kstrdup(buf, GFP_KERNEL);
  		if (!fsloc->locations[i].hosts)
  			goto out_free_all;
  		err = -EINVAL;
  		/* slash separated path component list */
  		len = qword_get(mesg, buf, PAGE_SIZE);
  		if (len <= 0)
  			goto out_free_all;
  		err = -ENOMEM;
  		fsloc->locations[i].path = kstrdup(buf, GFP_KERNEL);
  		if (!fsloc->locations[i].path)
  			goto out_free_all;
  	}
  	/* migrated */
  	err = get_int(mesg, &migrated);
  	if (err)
  		goto out_free_all;
  	err = -EINVAL;
  	if (migrated < 0 || migrated > 1)
  		goto out_free_all;
  	fsloc->migrated = migrated;
  	return 0;
  out_free_all:
  	nfsd4_fslocs_free(fsloc);
  	return err;
  }

  static int secinfo_parse(char **mesg, char *buf, struct svc_export *exp)
  {
  	int listsize, err;
  	struct exp_flavor_info *f;
  
  	err = get_int(mesg, &listsize);
  	if (err)
  		return err;
  	if (listsize < 0 || listsize > MAX_SECINFO_LIST)
  		return -EINVAL;
  
  	for (f = exp->ex_flavors; f < exp->ex_flavors + listsize; f++) {
  		err = get_int(mesg, &f->pseudoflavor);
  		if (err)
  			return err;
  		/*

  		 * XXX: It would be nice to also check whether this
  		 * pseudoflavor is supported, so we can discover the
  		 * problem at export time instead of when a client fails
  		 * to authenticate.

  		 */

  		err = get_int(mesg, &f->flags);
  		if (err)
  			return err;
  		/* Only some flags are allowed to differ between flavors: */
  		if (~NFSEXP_SECINFO_FLAGS & (f->flags ^ exp->ex_flags))
  			return -EINVAL;
  	}
  	exp->ex_nflavors = listsize;
  	return 0;
  }

  #else /* CONFIG_NFSD_V4 */

  static inline int
  fsloc_parse(char **mesg, char *buf, struct nfsd4_fs_locations *fsloc){return 0;}
  static inline int
  secinfo_parse(char **mesg, char *buf, struct svc_export *exp) { return 0; }

  #endif

  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 svc_export exp = {}, *expp;

  	int an_int;

  	if (mesg[mlen-1] != '
  ')
  		return -EINVAL;
  	mesg[mlen-1] = 0;
  
  	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);

  	if (!buf)
  		return -ENOMEM;

  
  	/* client */

  	err = -EINVAL;

  	len = qword_get(&mesg, buf, PAGE_SIZE);
  	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 out1;
  
  	err = kern_path(buf, 0, &exp.ex_path);
  	if (err)
  		goto out1;

  	exp.ex_client = dom;

  	/* expiry */
  	err = -EINVAL;
  	exp.h.expiry_time = get_expiry(&mesg);
  	if (exp.h.expiry_time == 0)

  		goto out3;

  
  	/* flags */
  	err = get_int(&mesg, &an_int);

  	if (err == -ENOENT) {
  		err = 0;

  		set_bit(CACHE_NEGATIVE, &exp.h.flags);

  	} else {

  		if (err || an_int < 0)
  			goto out3;

  		exp.ex_flags= an_int;
  	
  		/* anon uid */
  		err = get_int(&mesg, &an_int);

  		if (err)
  			goto out3;

  		exp.ex_anon_uid= an_int;
  
  		/* anon gid */
  		err = get_int(&mesg, &an_int);

  		if (err)
  			goto out3;

  		exp.ex_anon_gid= an_int;
  
  		/* fsid */
  		err = get_int(&mesg, &an_int);

  		if (err)
  			goto out3;

  		exp.ex_fsid = an_int;

  		while ((len = qword_get(&mesg, buf, PAGE_SIZE)) > 0) {
  			if (strcmp(buf, "fsloc") == 0)
  				err = fsloc_parse(&mesg, buf, &exp.ex_fslocs);
  			else if (strcmp(buf, "uuid") == 0) {
  				/* expect a 16 byte uuid encoded as \xXXXX... */
  				len = qword_get(&mesg, buf, PAGE_SIZE);
  				if (len != 16)
  					err  = -EINVAL;
  				else {
  					exp.ex_uuid =
  						kmemdup(buf, 16, GFP_KERNEL);
  					if (exp.ex_uuid == NULL)
  						err = -ENOMEM;
  				}

  			} else if (strcmp(buf, "secinfo") == 0)
  				err = secinfo_parse(&mesg, buf, &exp);
  			else

  				/* quietly ignore unknown words and anything
  				 * following. Newer user-space can try to set
  				 * new values, then see what the result was.
  				 */
  				break;
  			if (err)

  				goto out4;

  		}

  		err = check_export(exp.ex_path.dentry->d_inode, &exp.ex_flags,

  				   exp.ex_uuid);

  		if (err)
  			goto out4;

  	}

  	expp = svc_export_lookup(&exp);

  	if (expp)

  		expp = svc_export_update(&exp, expp);
  	else
  		err = -ENOMEM;

  	cache_flush();

  	if (expp == NULL)
  		err = -ENOMEM;
  	else
  		exp_put(expp);

  out4:

  	nfsd4_fslocs_free(&exp.ex_fslocs);
  	kfree(exp.ex_uuid);

  out3:

  	path_put(&exp.ex_path);
  out1:
  	auth_domain_put(dom);
  out:

  	kfree(buf);

  	return err;
  }

  static void exp_flags(struct seq_file *m, int flag, int fsid,
  		uid_t anonu, uid_t anong, struct nfsd4_fs_locations *fslocs);

  static void show_secinfo(struct seq_file *m, struct svc_export *exp);

  
  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)
  ");
  		return 0;
  	}
  	exp = container_of(h, struct svc_export, h);

  	seq_path(m, &exp->ex_path, " \t
  \\");

  	seq_putc(m, '\t');
  	seq_escape(m, exp->ex_client->name, " \t
  \\");
  	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, &exp->ex_fslocs);

  		if (exp->ex_uuid) {
  			int i;
  			seq_puts(m, ",uuid=");
  			for (i=0; i<16; i++) {
  				if ((i&3) == 0 && i)
  					seq_putc(m, ':');
  				seq_printf(m, "%02x", exp->ex_uuid[i]);
  			}
  		}

  		show_secinfo(m, exp);

  	}

  	seq_puts(m, ")
  ");
  	return 0;
  }

  static int svc_export_match(struct cache_head *a, struct cache_head *b)

  {

  	struct svc_export *orig = container_of(a, struct svc_export, h);
  	struct svc_export *new = container_of(b, struct svc_export, h);
  	return orig->ex_client == new->ex_client &&

  		orig->ex_path.dentry == new->ex_path.dentry &&
  		orig->ex_path.mnt == new->ex_path.mnt;

  }

  
  static void svc_export_init(struct cache_head *cnew, struct cache_head *citem)

  {

  	struct svc_export *new = container_of(cnew, struct svc_export, h);
  	struct svc_export *item = container_of(citem, struct svc_export, h);

  	kref_get(&item->ex_client->ref);

  	new->ex_client = item->ex_client;

  	new->ex_path.dentry = dget(item->ex_path.dentry);
  	new->ex_path.mnt = mntget(item->ex_path.mnt);

  	new->ex_fslocs.locations = NULL;
  	new->ex_fslocs.locations_count = 0;
  	new->ex_fslocs.migrated = 0;

  }

  static void export_update(struct cache_head *cnew, struct cache_head *citem)

  {

  	struct svc_export *new = container_of(cnew, struct svc_export, h);
  	struct svc_export *item = container_of(citem, struct svc_export, h);

  	int i;

  	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;

  	new->ex_uuid = item->ex_uuid;
  	item->ex_uuid = NULL;

  	new->ex_fslocs.locations = item->ex_fslocs.locations;
  	item->ex_fslocs.locations = NULL;
  	new->ex_fslocs.locations_count = item->ex_fslocs.locations_count;
  	item->ex_fslocs.locations_count = 0;
  	new->ex_fslocs.migrated = item->ex_fslocs.migrated;
  	item->ex_fslocs.migrated = 0;

  	new->ex_nflavors = item->ex_nflavors;
  	for (i = 0; i < MAX_SECINFO_LIST; i++) {
  		new->ex_flavors[i] = item->ex_flavors[i];
  	}

  }

  static struct cache_head *svc_export_alloc(void)
  {
  	struct svc_export *i = kmalloc(sizeof(*i), GFP_KERNEL);
  	if (i)
  		return &i->h;
  	else
  		return NULL;
  }
  
  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_upcall	= svc_export_upcall,

  	.cache_parse	= svc_export_parse,
  	.cache_show	= svc_export_show,
  	.match		= svc_export_match,
  	.init		= svc_export_init,
  	.update		= export_update,
  	.alloc		= svc_export_alloc,
  };

  static int
  svc_export_hash(struct svc_export *exp)

  {

  	int hash;

  	hash = hash_ptr(exp->ex_client, EXPORT_HASHBITS);

  	hash ^= hash_ptr(exp->ex_path.dentry, EXPORT_HASHBITS);
  	hash ^= hash_ptr(exp->ex_path.mnt, EXPORT_HASHBITS);

  	return hash;
  }
  
  static struct svc_export *
  svc_export_lookup(struct svc_export *exp)
  {
  	struct cache_head *ch;
  	int hash = svc_export_hash(exp);

  
  	ch = sunrpc_cache_lookup(&svc_export_cache, &exp->h,
  				 hash);
  	if (ch)
  		return container_of(ch, struct svc_export, h);
  	else
  		return NULL;
  }

  static struct svc_export *

  svc_export_update(struct svc_export *new, struct svc_export *old)
  {
  	struct cache_head *ch;

  	int hash = svc_export_hash(old);

  
  	ch = sunrpc_cache_update(&svc_export_cache, &new->h,
  				 &old->h,
  				 hash);
  	if (ch)
  		return container_of(ch, struct svc_export, h);
  	else
  		return NULL;
  }

  static 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 ERR_PTR(-ENOENT);

  
  	key.ek_client = clp;
  	key.ek_fsidtype = fsid_type;
  	memcpy(key.ek_fsid, fsidv, key_len(fsid_type));

  	ek = svc_expkey_lookup(&key);

  	if (ek == NULL)
  		return ERR_PTR(-ENOMEM);
  	err = cache_check(&svc_expkey_cache, &ek->h, reqp);
  	if (err)
  		return ERR_PTR(err);

  	return ek;
  }

  static svc_export *exp_get_by_name(svc_client *clp, const struct path *path,
  				     struct cache_req *reqp)

  {
  	struct svc_export *exp, key;

  	int err;

  	if (!clp)

  		return ERR_PTR(-ENOENT);

  
  	key.ex_client = clp;

  	key.ex_path = *path;

  	exp = svc_export_lookup(&key);

  	if (exp == NULL)
  		return ERR_PTR(-ENOMEM);
  	err = cache_check(&svc_export_cache, &exp->h, reqp);
  	if (err)
  		return ERR_PTR(err);

  	return exp;
  }
  
  /*
   * Find the export entry for a given dentry.
   */

  static struct svc_export *exp_parent(svc_client *clp, struct path *path)

  {

  	struct dentry *saved = dget(path->dentry);
  	svc_export *exp = exp_get_by_name(clp, path, NULL);
  
  	while (PTR_ERR(exp) == -ENOENT && !IS_ROOT(path->dentry)) {
  		struct dentry *parent = dget_parent(path->dentry);
  		dput(path->dentry);
  		path->dentry = parent;
  		exp = exp_get_by_name(clp, path, NULL);

  	}

  	dput(path->dentry);
  	path->dentry = saved;

  	return exp;
  }

  
  /*
   * 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 *name, struct knfsd_fh *f, int maxsize)

  {
  	struct svc_export	*exp;

  	struct path		path;

  	struct inode		*inode;
  	struct svc_fh		fh;
  	int			err;
  
  	err = -EPERM;
  	/* NB: we probably ought to check that it's NUL-terminated */

  	if (kern_path(name, 0, &path)) {
  		printk("nfsd: exp_rootfh path not found %s", name);

  		return err;
  	}

  	inode = path.dentry->d_inode;

  
  	dprintk("nfsd: exp_rootfh(%s [%p] %s:%s/%ld)
  ",

  		 name, path.dentry, clp->name,

  		 inode->i_sb->s_id, inode->i_ino);

  	exp = exp_parent(clp, &path);

  	if (IS_ERR(exp)) {
  		err = PTR_ERR(exp);
  		goto out;
  	}

  
  	/*
  	 * fh must be initialized before calling fh_compose
  	 */
  	fh_init(&fh, maxsize);

  	if (fh_compose(&fh, exp, path.dentry, NULL))

  		err = -EINVAL;
  	else
  		err = 0;
  	memcpy(f, &fh.fh_handle, sizeof(struct knfsd_fh));
  	fh_put(&fh);
  	exp_put(exp);
  out:

  	path_put(&path);

  	return err;
  }

  static struct svc_export *exp_find(struct auth_domain *clp, int fsid_type,
  				   u32 *fsidv, struct cache_req *reqp)

  {
  	struct svc_export *exp;
  	struct svc_expkey *ek = exp_find_key(clp, fsid_type, fsidv, reqp);

  	if (IS_ERR(ek))

  		return ERR_CAST(ek);

  	exp = exp_get_by_name(clp, &ek->ek_path, reqp);

  	cache_put(&ek->h, &svc_expkey_cache);

  	if (IS_ERR(exp))

  		return ERR_CAST(exp);

  	return exp;
  }

  __be32 check_nfsd_access(struct svc_export *exp, struct svc_rqst *rqstp)
  {
  	struct exp_flavor_info *f;
  	struct exp_flavor_info *end = exp->ex_flavors + exp->ex_nflavors;
  
  	/* legacy gss-only clients are always OK: */
  	if (exp->ex_client == rqstp->rq_gssclient)
  		return 0;
  	/* ip-address based client; check sec= export option: */
  	for (f = exp->ex_flavors; f < end; f++) {
  		if (f->pseudoflavor == rqstp->rq_flavor)
  			return 0;
  	}
  	/* defaults in absence of sec= options: */
  	if (exp->ex_nflavors == 0) {
  		if (rqstp->rq_flavor == RPC_AUTH_NULL ||
  		    rqstp->rq_flavor == RPC_AUTH_UNIX)
  			return 0;
  	}
  	return nfserr_wrongsec;
  }

  /*

   * Uses rq_client and rq_gssclient to find an export; uses rq_client (an
   * auth_unix client) if it's available and has secinfo information;
   * otherwise, will try to use rq_gssclient.
   *

   * Called from functions that handle requests; functions that do work on
   * behalf of mountd are passed a single client name to use, and should
   * use exp_get_by_name() or exp_find().
   */
  struct svc_export *

  rqst_exp_get_by_name(struct svc_rqst *rqstp, struct path *path)

  {

  	struct svc_export *gssexp, *exp = ERR_PTR(-ENOENT);

  
  	if (rqstp->rq_client == NULL)
  		goto gss;

  	/* First try the auth_unix client: */

  	exp = exp_get_by_name(rqstp->rq_client, path, &rqstp->rq_chandle);

  	if (PTR_ERR(exp) == -ENOENT)
  		goto gss;
  	if (IS_ERR(exp))
  		return exp;
  	/* If it has secinfo, assume there are no gss/... clients */
  	if (exp->ex_nflavors > 0)
  		return exp;
  gss:
  	/* Otherwise, try falling back on gss client */
  	if (rqstp->rq_gssclient == NULL)
  		return exp;

  	gssexp = exp_get_by_name(rqstp->rq_gssclient, path, &rqstp->rq_chandle);

  	if (PTR_ERR(gssexp) == -ENOENT)
  		return exp;

  	if (!IS_ERR(exp))

  		exp_put(exp);
  	return gssexp;

  }
  
  struct svc_export *
  rqst_exp_find(struct svc_rqst *rqstp, int fsid_type, u32 *fsidv)
  {

  	struct svc_export *gssexp, *exp = ERR_PTR(-ENOENT);

  
  	if (rqstp->rq_client == NULL)
  		goto gss;

  	/* First try the auth_unix client: */
  	exp = exp_find(rqstp->rq_client, fsid_type, fsidv, &rqstp->rq_chandle);
  	if (PTR_ERR(exp) == -ENOENT)
  		goto gss;
  	if (IS_ERR(exp))
  		return exp;
  	/* If it has secinfo, assume there are no gss/... clients */
  	if (exp->ex_nflavors > 0)
  		return exp;
  gss:
  	/* Otherwise, try falling back on gss client */
  	if (rqstp->rq_gssclient == NULL)
  		return exp;
  	gssexp = exp_find(rqstp->rq_gssclient, fsid_type, fsidv,
  						&rqstp->rq_chandle);
  	if (PTR_ERR(gssexp) == -ENOENT)
  		return exp;

  	if (!IS_ERR(exp))

  		exp_put(exp);
  	return gssexp;

  }
  
  struct svc_export *

  rqst_exp_parent(struct svc_rqst *rqstp, struct path *path)

  {

  	struct dentry *saved = dget(path->dentry);
  	struct svc_export *exp = rqst_exp_get_by_name(rqstp, path);

  	while (PTR_ERR(exp) == -ENOENT && !IS_ROOT(path->dentry)) {
  		struct dentry *parent = dget_parent(path->dentry);
  		dput(path->dentry);
  		path->dentry = parent;
  		exp = rqst_exp_get_by_name(rqstp, path);

  	}

  	dput(path->dentry);
  	path->dentry = saved;

  	return exp;

  }

  struct svc_export *rqst_find_fsidzero_export(struct svc_rqst *rqstp)

  {

  	u32 fsidv[2];
  
  	mk_fsid(FSID_NUM, fsidv, 0, 0, 0, NULL);

  	return rqst_exp_find(rqstp, FSID_NUM, fsidv);

  }

  /*
   * 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
   */

  __be32

  exp_pseudoroot(struct svc_rqst *rqstp, struct svc_fh *fhp)

  {

  	struct svc_export *exp;

  	__be32 rv;

  	exp = rqst_find_fsidzero_export(rqstp);

  	if (IS_ERR(exp))
  		return nfserrno(PTR_ERR(exp));

  	rv = fh_compose(fhp, exp, exp->ex_path.dentry, NULL);

  	exp_put(exp);

  	return rv;
  }
  
  /* Iterator */
  
  static void *e_start(struct seq_file *m, loff_t *pos)

  	__acquires(svc_export_cache.hash_lock)

  {
  	loff_t n = *pos;
  	unsigned hash, export;
  	struct cache_head *ch;
  	

  	read_lock(&svc_export_cache.hash_lock);
  	if (!n--)

  		return SEQ_START_TOKEN;

  	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 == SEQ_START_TOKEN)

  		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)

  	__releases(svc_export_cache.hash_lock)

  {
  	read_unlock(&svc_export_cache.hash_lock);

  }
  
  static struct flags {
  	int flag;
  	char *name[2];
  } expflags[] = {
  	{ NFSEXP_READONLY, {"ro", "rw"}},
  	{ NFSEXP_INSECURE_PORT, {"insecure", ""}},
  	{ NFSEXP_ROOTSQUASH, {"root_squash", "no_root_squash"}},
  	{ NFSEXP_ALLSQUASH, {"all_squash", ""}},
  	{ NFSEXP_ASYNC, {"async", "sync"}},
  	{ NFSEXP_GATHERED_WRITES, {"wdelay", "no_wdelay"}},
  	{ NFSEXP_NOHIDE, {"nohide", ""}},
  	{ NFSEXP_CROSSMOUNT, {"crossmnt", ""}},
  	{ NFSEXP_NOSUBTREECHECK, {"no_subtree_check", ""}},
  	{ NFSEXP_NOAUTHNLM, {"insecure_locks", ""}},

  	{ NFSEXP_V4ROOT, {"v4root", ""}},

  	{ 0, {"", ""}}
  };

  static void show_expflags(struct seq_file *m, int flags, int mask)

  {

  	struct flags *flg;

  	int state, first = 0;

  
  	for (flg = expflags; flg->flag; flg++) {

  		if (flg->flag & ~mask)
  			continue;
  		state = (flg->flag & flags) ? 0 : 1;

  		if (*flg->name[state])
  			seq_printf(m, "%s%s", first++?",":"", flg->name[state]);
  	}

  }

  static void show_secinfo_flags(struct seq_file *m, int flags)
  {
  	seq_printf(m, ",");
  	show_expflags(m, flags, NFSEXP_SECINFO_FLAGS);
  }

  static bool secinfo_flags_equal(int f, int g)
  {
  	f &= NFSEXP_SECINFO_FLAGS;
  	g &= NFSEXP_SECINFO_FLAGS;
  	return f == g;
  }
  
  static int show_secinfo_run(struct seq_file *m, struct exp_flavor_info **fp, struct exp_flavor_info *end)
  {
  	int flags;
  
  	flags = (*fp)->flags;
  	seq_printf(m, ",sec=%d", (*fp)->pseudoflavor);
  	(*fp)++;
  	while (*fp != end && secinfo_flags_equal(flags, (*fp)->flags)) {
  		seq_printf(m, ":%d", (*fp)->pseudoflavor);
  		(*fp)++;
  	}
  	return flags;
  }

  static void show_secinfo(struct seq_file *m, struct svc_export *exp)
  {
  	struct exp_flavor_info *f;
  	struct exp_flavor_info *end = exp->ex_flavors + exp->ex_nflavors;

  	int flags;

  
  	if (exp->ex_nflavors == 0)
  		return;

  	f = exp->ex_flavors;
  	flags = show_secinfo_run(m, &f, end);
  	if (!secinfo_flags_equal(flags, exp->ex_flags))
  		show_secinfo_flags(m, flags);
  	while (f != end) {
  		flags = show_secinfo_run(m, &f, end);
  		show_secinfo_flags(m, flags);

  	}

  }

  static void exp_flags(struct seq_file *m, int flag, int fsid,
  		uid_t anonu, uid_t anong, struct nfsd4_fs_locations *fsloc)
  {
  	show_expflags(m, flag, NFSEXP_ALLFLAGS);

  	if (flag & NFSEXP_FSID)

  		seq_printf(m, ",fsid=%d", fsid);

  	if (anonu != (uid_t)-2 && anonu != (0x10000-2))

  		seq_printf(m, ",anonuid=%u", anonu);

  	if (anong != (gid_t)-2 && anong != (0x10000-2))

  		seq_printf(m, ",anongid=%u", anong);

  	if (fsloc && fsloc->locations_count > 0) {
  		char *loctype = (fsloc->migrated) ? "refer" : "replicas";
  		int i;

  		seq_printf(m, ",%s=", loctype);

  		seq_escape(m, fsloc->locations[0].path, ",;@ \t
  \\");
  		seq_putc(m, '@');
  		seq_escape(m, fsloc->locations[0].hosts, ",;@ \t
  \\");
  		for (i = 1; i < fsloc->locations_count; i++) {
  			seq_putc(m, ';');
  			seq_escape(m, fsloc->locations[i].path, ",;@ \t
  \\");
  			seq_putc(m, '@');
  			seq_escape(m, fsloc->locations[i].hosts, ",;@ \t
  \\");
  		}
  	}

  }
  
  static int e_show(struct seq_file *m, void *p)
  {
  	struct cache_head *cp = p;
  	struct svc_export *exp = container_of(cp, struct svc_export, h);

  	if (p == SEQ_START_TOKEN) {

  		seq_puts(m, "# Version 1.1
  ");
  		seq_puts(m, "# Path Client(Flags) # IPs
  ");
  		return 0;
  	}

  	cache_get(&exp->h);
  	if (cache_check(&svc_export_cache, &exp->h, NULL))
  		return 0;

  	cache_put(&exp->h, &svc_export_cache);

  	return svc_export_show(m, &svc_export_cache, cp);
  }

  const struct seq_operations nfs_exports_op = {

  	.start	= e_start,
  	.next	= e_next,
  	.stop	= e_stop,
  	.show	= e_show,
  };

  
  /*
   * Initialize the exports module.
   */

  int

  nfsd_export_init(void)
  {

  	int rv;

  	dprintk("nfsd: initializing export module.
  ");

  	rv = cache_register(&svc_export_cache);
  	if (rv)
  		return rv;
  	rv = cache_register(&svc_expkey_cache);
  	if (rv)
  		cache_unregister(&svc_export_cache);
  	return rv;

  
  }
  
  /*
   * Flush exports table - called when last nfsd thread is killed
   */
  void
  nfsd_export_flush(void)
  {

  	cache_purge(&svc_expkey_cache);
  	cache_purge(&svc_export_cache);

  }
  
  /*
   * Shutdown the exports module.
   */
  void
  nfsd_export_shutdown(void)
  {
  
  	dprintk("nfsd: shutting down export module.
  ");

  	cache_unregister(&svc_expkey_cache);
  	cache_unregister(&svc_export_cache);

  	svcauth_unix_purge();

  	dprintk("nfsd: export shutdown complete.
  ");
  }