Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / fs / nfsd / export.c
diff --git a/kernel/fs/nfsd/export.c b/kernel/fs/nfsd/export.c
new file mode 100644 (file)
index 0000000..f79521a
--- /dev/null
@@ -0,0 +1,1345 @@
+/*
+ * 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 <linux/sunrpc/svc_xprt.h>
+
+#include "nfsd.h"
+#include "nfsfh.h"
+#include "netns.h"
+#include "pnfs.h"
+
+#define NFSDDBG_FACILITY       NFSDDBG_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 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] = '\n';
+}
+
+static struct svc_expkey *svc_expkey_update(struct cache_detail *cd, struct svc_expkey *new,
+                                           struct svc_expkey *old);
+static struct svc_expkey *svc_expkey_lookup(struct cache_detail *cd, struct svc_expkey *);
+
+static int expkey_parse(struct cache_detail *cd, char *mesg, int mlen)
+{
+       /* client fsidtype fsid expiry [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] != '\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 (key_len(fsidtype)==0) /* invalid type */
+               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);
+
+       ek = svc_expkey_lookup(cd, &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>\n", buf);
+       err = 0;
+       if (len == 0) {
+               set_bit(CACHE_NEGATIVE, &key.h.flags);
+               ek = svc_expkey_update(cd, &key, ek);
+               if (!ek)
+                       err = -ENOMEM;
+       } else {
+               err = kern_path(buf, 0, &key.ek_path);
+               if (err)
+                       goto out;
+
+               dprintk("Found the path %s\n", buf);
+
+               ek = svc_expkey_update(cd, &key, ek);
+               if (!ek)
+                       err = -ENOMEM;
+               path_put(&key.ek_path);
+       }
+       cache_flush();
+ out:
+       if (ek)
+               cache_put(&ek->h, cd);
+       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]\n");
+               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\n");
+       }
+       seq_printf(m, "\n");
+       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_template = {
+       .owner          = THIS_MODULE,
+       .hash_size      = EXPKEY_HASHMAX,
+       .name           = "nfsd.fh",
+       .cache_put      = expkey_put,
+       .cache_request  = expkey_request,
+       .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 cache_detail *cd, struct svc_expkey *item)
+{
+       struct cache_head *ch;
+       int hash = svc_expkey_hash(item);
+
+       ch = sunrpc_cache_lookup(cd, &item->h, hash);
+       if (ch)
+               return container_of(ch, struct svc_expkey, h);
+       else
+               return NULL;
+}
+
+static struct svc_expkey *
+svc_expkey_update(struct cache_detail *cd, struct svc_expkey *new,
+                 struct svc_expkey *old)
+{
+       struct cache_head *ch;
+       int hash = svc_expkey_hash(new);
+
+       ch = sunrpc_cache_update(cd, &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 void nfsd4_fslocs_free(struct nfsd4_fs_locations *fsloc)
+{
+       struct nfsd4_fs_location *locations = fsloc->locations;
+       int i;
+
+       if (!locations)
+               return;
+
+       for (i = 0; i < fsloc->locations_count; i++) {
+               kfree(locations[i].path);
+               kfree(locations[i].hosts);
+       }
+
+       kfree(locations);
+       fsloc->locations = NULL;
+}
+
+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->ex_uuid);
+       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] = '\n';
+               return;
+       }
+       qword_add(bpp, blen, pth);
+       (*bpp)[-1] = '\n';
+}
+
+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\n");
+               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.\n");
+               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;
+
+       /* more than one fsloc */
+       if (fsloc->locations)
+               return -EINVAL;
+
+       /* listsize */
+       err = get_uint(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)
+{
+       struct exp_flavor_info *f;
+       u32 listsize;
+       int err;
+
+       /* more than one secinfo */
+       if (exp->ex_nflavors)
+               return -EINVAL;
+
+       err = get_uint(mesg, &listsize);
+       if (err)
+               return err;
+       if (listsize > MAX_SECINFO_LIST)
+               return -EINVAL;
+
+       for (f = exp->ex_flavors; f < exp->ex_flavors + listsize; f++) {
+               err = get_uint(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_uint(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 inline int
+uuid_parse(char **mesg, char *buf, unsigned char **puuid)
+{
+       int len;
+
+       /* more than one uuid */
+       if (*puuid)
+               return -EINVAL;
+
+       /* expect a 16 byte uuid encoded as \xXXXX... */
+       len = qword_get(mesg, buf, PAGE_SIZE);
+       if (len != EX_UUID_LEN)
+               return -EINVAL;
+
+       *puuid = kmemdup(buf, EX_UUID_LEN, GFP_KERNEL);
+       if (*puuid == NULL)
+               return -ENOMEM;
+
+       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 svc_export exp = {}, *expp;
+       int an_int;
+
+       if (mesg[mlen-1] != '\n')
+               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;
+       exp.cd = cd;
+       exp.ex_devid_map = NULL;
+
+       /* 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= make_kuid(&init_user_ns, an_int);
+
+               /* anon gid */
+               err = get_int(&mesg, &an_int);
+               if (err)
+                       goto out3;
+               exp.ex_anon_gid= make_kgid(&init_user_ns, 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)
+                               err = uuid_parse(&mesg, buf, &exp.ex_uuid);
+                       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(d_inode(exp.ex_path.dentry), &exp.ex_flags,
+                                  exp.ex_uuid);
+               if (err)
+                       goto out4;
+               /*
+                * No point caching this if it would immediately expire.
+                * Also, this protects exportfs's dummy export from the
+                * anon_uid/anon_gid checks:
+                */
+               if (exp.h.expiry_time < seconds_since_boot())
+                       goto out4;
+               /*
+                * For some reason exportfs has been passing down an
+                * invalid (-1) uid & gid on the "dummy" export which it
+                * uses to test export support.  To make sure exportfs
+                * sees errors from check_export we therefore need to
+                * delay these checks till after check_export:
+                */
+               err = -EINVAL;
+               if (!uid_valid(exp.ex_anon_uid))
+                       goto out4;
+               if (!gid_valid(exp.ex_anon_gid))
+                       goto out4;
+               err = 0;
+
+               nfsd4_setup_layout_type(&exp);
+       }
+
+       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,
+               kuid_t anonu, kgid_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)\n");
+               return 0;
+       }
+       exp = container_of(h, struct svc_export, h);
+       seq_path(m, &exp->ex_path, " \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, &exp->ex_fslocs);
+               if (exp->ex_uuid) {
+                       int i;
+                       seq_puts(m, ",uuid=");
+                       for (i = 0; i < EX_UUID_LEN; i++) {
+                               if ((i&3) == 0 && i)
+                                       seq_putc(m, ':');
+                               seq_printf(m, "%02x", exp->ex_uuid[i]);
+                       }
+               }
+               show_secinfo(m, exp);
+       }
+       seq_puts(m, ")\n");
+       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 &&
+               path_equal(&orig->ex_path, &new->ex_path);
+}
+
+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 = item->ex_path;
+       path_get(&item->ex_path);
+       new->ex_fslocs.locations = NULL;
+       new->ex_fslocs.locations_count = 0;
+       new->ex_fslocs.migrated = 0;
+       new->ex_layout_type = 0;
+       new->ex_uuid = NULL;
+       new->cd = item->cd;
+}
+
+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_devid_map = item->ex_devid_map;
+       item->ex_devid_map = NULL;
+       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_layout_type = item->ex_layout_type;
+       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;
+}
+
+static struct cache_detail svc_export_cache_template = {
+       .owner          = THIS_MODULE,
+       .hash_size      = EXPORT_HASHMAX,
+       .name           = "nfsd.export",
+       .cache_put      = svc_export_put,
+       .cache_request  = svc_export_request,
+       .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(exp->cd, &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(old->cd, &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(struct cache_detail *cd, struct auth_domain *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(cd, &key);
+       if (ek == NULL)
+               return ERR_PTR(-ENOMEM);
+       err = cache_check(cd, &ek->h, reqp);
+       if (err)
+               return ERR_PTR(err);
+       return ek;
+}
+
+static struct svc_export *
+exp_get_by_name(struct cache_detail *cd, struct auth_domain *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;
+       key.cd = cd;
+
+       exp = svc_export_lookup(&key);
+       if (exp == NULL)
+               return ERR_PTR(-ENOMEM);
+       err = cache_check(cd, &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(struct cache_detail *cd, struct auth_domain *clp, struct path *path)
+{
+       struct dentry *saved = dget(path->dentry);
+       struct svc_export *exp = exp_get_by_name(cd, 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(cd, 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(struct net *net, struct auth_domain *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;
+       struct nfsd_net         *nn = net_generic(net, nfsd_net_id);
+       struct cache_detail     *cd = nn->svc_export_cache;
+
+       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 = d_inode(path.dentry);
+
+       dprintk("nfsd: exp_rootfh(%s [%p] %s:%s/%ld)\n",
+                name, path.dentry, clp->name,
+                inode->i_sb->s_id, inode->i_ino);
+       exp = exp_parent(cd, 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 cache_detail *cd,
+                                  struct auth_domain *clp, int fsid_type,
+                                  u32 *fsidv, struct cache_req *reqp)
+{
+       struct svc_export *exp;
+       struct nfsd_net *nn = net_generic(cd->net, nfsd_net_id);
+       struct svc_expkey *ek = exp_find_key(nn->svc_expkey_cache, clp, fsid_type, fsidv, reqp);
+       if (IS_ERR(ek))
+               return ERR_CAST(ek);
+
+       exp = exp_get_by_name(cd, clp, &ek->ek_path, reqp);
+       cache_put(&ek->h, nn->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_cred.cr_flavor)
+                       return 0;
+       }
+       /* defaults in absence of sec= options: */
+       if (exp->ex_nflavors == 0) {
+               if (rqstp->rq_cred.cr_flavor == RPC_AUTH_NULL ||
+                   rqstp->rq_cred.cr_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);
+       struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+       struct cache_detail *cd = nn->svc_export_cache;
+
+       if (rqstp->rq_client == NULL)
+               goto gss;
+
+       /* First try the auth_unix client: */
+       exp = exp_get_by_name(cd, 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(cd, 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);
+       struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+       struct cache_detail *cd = nn->svc_export_cache;
+
+       if (rqstp->rq_client == NULL)
+               goto gss;
+
+       /* First try the auth_unix client: */
+       exp = exp_find(cd, 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(cd, 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(((struct cache_detail *)m->private)->hash_lock)
+{
+       loff_t n = *pos;
+       unsigned hash, export;
+       struct cache_head *ch;
+       struct cache_detail *cd = m->private;
+       struct cache_head **export_table = cd->hash_table;
+
+       read_lock(&cd->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);
+       struct cache_detail *cd = m->private;
+       struct cache_head **export_table = cd->hash_table;
+
+       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(((struct cache_detail *)m->private)->hash_lock)
+{
+       struct cache_detail *cd = m->private;
+
+       read_unlock(&cd->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_NOREADDIRPLUS, {"nordirplus", ""}},
+       { NFSEXP_NOHIDE, {"nohide", ""}},
+       { NFSEXP_CROSSMOUNT, {"crossmnt", ""}},
+       { NFSEXP_NOSUBTREECHECK, {"no_subtree_check", ""}},
+       { NFSEXP_NOAUTHNLM, {"insecure_locks", ""}},
+       { NFSEXP_V4ROOT, {"v4root", ""}},
+       { NFSEXP_PNFS, {"pnfs", ""}},
+       { 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,
+               kuid_t anonu, kgid_t anong, struct nfsd4_fs_locations *fsloc)
+{
+       show_expflags(m, flag, NFSEXP_ALLFLAGS);
+       if (flag & NFSEXP_FSID)
+               seq_printf(m, ",fsid=%d", fsid);
+       if (!uid_eq(anonu, make_kuid(&init_user_ns, (uid_t)-2)) &&
+           !uid_eq(anonu, make_kuid(&init_user_ns, 0x10000-2)))
+               seq_printf(m, ",anonuid=%u", from_kuid(&init_user_ns, anonu));
+       if (!gid_eq(anong, make_kgid(&init_user_ns, (gid_t)-2)) &&
+           !gid_eq(anong, make_kgid(&init_user_ns, 0x10000-2)))
+               seq_printf(m, ",anongid=%u", from_kgid(&init_user_ns, 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\n\\");
+               seq_putc(m, '@');
+               seq_escape(m, fsloc->locations[0].hosts, ",;@ \t\n\\");
+               for (i = 1; i < fsloc->locations_count; i++) {
+                       seq_putc(m, ';');
+                       seq_escape(m, fsloc->locations[i].path, ",;@ \t\n\\");
+                       seq_putc(m, '@');
+                       seq_escape(m, fsloc->locations[i].hosts, ",;@ \t\n\\");
+               }
+       }
+}
+
+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);
+       struct cache_detail *cd = m->private;
+
+       if (p == SEQ_START_TOKEN) {
+               seq_puts(m, "# Version 1.1\n");
+               seq_puts(m, "# Path Client(Flags) # IPs\n");
+               return 0;
+       }
+
+       exp_get(exp);
+       if (cache_check(cd, &exp->h, NULL))
+               return 0;
+       exp_put(exp);
+       return svc_export_show(m, cd, 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(struct net *net)
+{
+       int rv;
+       struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+       dprintk("nfsd: initializing export module (net: %p).\n", net);
+
+       nn->svc_export_cache = cache_create_net(&svc_export_cache_template, net);
+       if (IS_ERR(nn->svc_export_cache))
+               return PTR_ERR(nn->svc_export_cache);
+       rv = cache_register_net(nn->svc_export_cache, net);
+       if (rv)
+               goto destroy_export_cache;
+
+       nn->svc_expkey_cache = cache_create_net(&svc_expkey_cache_template, net);
+       if (IS_ERR(nn->svc_expkey_cache)) {
+               rv = PTR_ERR(nn->svc_expkey_cache);
+               goto unregister_export_cache;
+       }
+       rv = cache_register_net(nn->svc_expkey_cache, net);
+       if (rv)
+               goto destroy_expkey_cache;
+       return 0;
+
+destroy_expkey_cache:
+       cache_destroy_net(nn->svc_expkey_cache, net);
+unregister_export_cache:
+       cache_unregister_net(nn->svc_export_cache, net);
+destroy_export_cache:
+       cache_destroy_net(nn->svc_export_cache, net);
+       return rv;
+}
+
+/*
+ * Flush exports table - called when last nfsd thread is killed
+ */
+void
+nfsd_export_flush(struct net *net)
+{
+       struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+       cache_purge(nn->svc_expkey_cache);
+       cache_purge(nn->svc_export_cache);
+}
+
+/*
+ * Shutdown the exports module.
+ */
+void
+nfsd_export_shutdown(struct net *net)
+{
+       struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+       dprintk("nfsd: shutting down export module (net: %p).\n", net);
+
+       cache_unregister_net(nn->svc_expkey_cache, net);
+       cache_unregister_net(nn->svc_export_cache, net);
+       cache_destroy_net(nn->svc_expkey_cache, net);
+       cache_destroy_net(nn->svc_export_cache, net);
+       svcauth_unix_purge(net);
+
+       dprintk("nfsd: export shutdown complete (net: %p).\n", net);
+}