module/zfs/zpl_export.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 2011 Gunnar Beutner
  23  */
  24
  25
  26 #include <sys/zfs_vnops.h>
  27 #include <sys/zfs_znode.h>
  28 #include <sys/zpl.h>
  29
  30
  31 static int
  32 zpl_encode_fh(struct dentry *dentry, __u32 *fh, int *max_len, int connectable)
  33 {
  34         fid_t *fid = (fid_t *)fh;
  35         struct inode *ip = dentry->d_inode;
  36         int len_bytes, rc;
  37
  38         len_bytes = *max_len * sizeof (__u32);
  39
  40         if (len_bytes < offsetof(fid_t, fid_data))
  41                 return 255;
  42
  43         fid->fid_len = len_bytes - offsetof(fid_t, fid_data);
  44
  45         rc = zfs_fid(ip, fid);
  46
  47         len_bytes = offsetof(fid_t, fid_data) + fid->fid_len;
  48         *max_len = roundup(len_bytes, sizeof (__u32)) / sizeof (__u32);
  49
  50         return (rc == 0 ? FILEID_INO32_GEN : 255);
  51 }
  52
  53 static struct dentry *
  54 zpl_dentry_obtain_alias(struct inode *ip)
  55 {
  56         struct dentry *result;
  57
  58 #ifdef HAVE_D_OBTAIN_ALIAS
  59         result = d_obtain_alias(ip);
  60 #else
  61         result = d_alloc_anon(ip);
  62
  63         if (result == NULL) {
  64                 iput(ip);
  65                 result = ERR_PTR(-ENOMEM);
  66         }
  67 #endif /* HAVE_D_OBTAIN_ALIAS */
  68
  69         return result;
  70 }
  71
  72 static struct dentry *
  73 zpl_fh_to_dentry(struct super_block *sb, struct fid *fh,
  74     int fh_len, int fh_type)
  75 {
  76         fid_t *fid = (fid_t *)fh;
  77         struct inode *ip;
  78         int len_bytes, rc;
  79
  80         len_bytes = fh_len * sizeof (__u32);
  81
  82         if (fh_type != FILEID_INO32_GEN ||
  83             len_bytes < offsetof(fid_t, fid_data) ||
  84             len_bytes < offsetof(fid_t, fid_data) + fid->fid_len)
  85                 return ERR_PTR(-EINVAL);
  86
  87         rc = zfs_vget(sb, &ip, fid);
  88
  89         if (rc != 0)
  90                 return ERR_PTR(-rc);
  91
  92         ASSERT((ip != NULL) && !IS_ERR(ip));
  93
  94         return zpl_dentry_obtain_alias(ip);
  95 }
  96
  97 static struct dentry *
  98 zpl_get_parent(struct dentry *child)
  99 {
 100         cred_t *cr = CRED();
 101         struct inode *ip;
 102         int error;
 103
 104         crhold(cr);
 105         error = -zfs_lookup(child->d_inode, "..", &ip, 0, cr, NULL, NULL);
 106         crfree(cr);
 107         ASSERT3S(error, <=, 0);
 108
 109         if (error)
 110                 return ERR_PTR(error);
 111
 112         return zpl_dentry_obtain_alias(ip);
 113 }
 114
 115 const struct export_operations zpl_export_operations = {
 116         .encode_fh      = zpl_encode_fh,
 117         .fh_to_dentry   = zpl_fh_to_dentry,
 118         .get_parent     = zpl_get_parent
 119 };