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/zfs_ctldir.h>
  29 #include <sys/zpl.h>
  30
  31
  32 static int
  33 #ifdef HAVE_ENCODE_FH_WITH_INODE
  34 zpl_encode_fh(struct inode *ip, __u32 *fh, int *max_len, struct inode *parent)
  35 {
  36 #else
  37 zpl_encode_fh(struct dentry *dentry, __u32 *fh, int *max_len, int connectable)
  38 {
  39         struct inode *ip = dentry->d_inode;
  40 #endif /* HAVE_ENCODE_FH_WITH_INODE */
  41         fid_t *fid = (fid_t *)fh;
  42         int len_bytes, rc;
  43
  44         len_bytes = *max_len * sizeof (__u32);
  45
  46         if (len_bytes < offsetof(fid_t, fid_data))
  47                 return 255;
  48
  49         fid->fid_len = len_bytes - offsetof(fid_t, fid_data);
  50
  51         if (zfsctl_is_node(ip))
  52                 rc = zfsctl_fid(ip, fid);
  53         else
  54                 rc = zfs_fid(ip, fid);
  55
  56         len_bytes = offsetof(fid_t, fid_data) + fid->fid_len;
  57         *max_len = roundup(len_bytes, sizeof (__u32)) / sizeof (__u32);
  58
  59         return (rc == 0 ? FILEID_INO32_GEN : 255);
  60 }
  61
  62 static struct dentry *
  63 zpl_dentry_obtain_alias(struct inode *ip)
  64 {
  65         struct dentry *result;
  66
  67 #ifdef HAVE_D_OBTAIN_ALIAS
  68         result = d_obtain_alias(ip);
  69 #else
  70         result = d_alloc_anon(ip);
  71
  72         if (result == NULL) {
  73                 iput(ip);
  74                 result = ERR_PTR(-ENOMEM);
  75         }
  76 #endif /* HAVE_D_OBTAIN_ALIAS */
  77
  78         return result;
  79 }
  80
  81 static struct dentry *
  82 zpl_fh_to_dentry(struct super_block *sb, struct fid *fh,
  83     int fh_len, int fh_type)
  84 {
  85         fid_t *fid = (fid_t *)fh;
  86         struct inode *ip;
  87         int len_bytes, rc;
  88
  89         len_bytes = fh_len * sizeof (__u32);
  90
  91         if (fh_type != FILEID_INO32_GEN ||
  92             len_bytes < offsetof(fid_t, fid_data) ||
  93             len_bytes < offsetof(fid_t, fid_data) + fid->fid_len)
  94                 return ERR_PTR(-EINVAL);
  95
  96         rc = zfs_vget(sb, &ip, fid);
  97
  98         if (rc != 0)
  99                 return ERR_PTR(-rc);
 100
 101         ASSERT((ip != NULL) && !IS_ERR(ip));
 102
 103         return zpl_dentry_obtain_alias(ip);
 104 }
 105
 106 static struct dentry *
 107 zpl_get_parent(struct dentry *child)
 108 {
 109         cred_t *cr = CRED();
 110         struct inode *ip;
 111         int error;
 112
 113         crhold(cr);
 114         error = -zfs_lookup(child->d_inode, "..", &ip, 0, cr, NULL, NULL);
 115         crfree(cr);
 116         ASSERT3S(error, <=, 0);
 117
 118         if (error)
 119                 return ERR_PTR(error);
 120
 121         return zpl_dentry_obtain_alias(ip);
 122 }
 123
 124 const struct export_operations zpl_export_operations = {
 125         .encode_fh      = zpl_encode_fh,
 126         .fh_to_dentry   = zpl_fh_to_dentry,
 127         .get_parent     = zpl_get_parent
 128 };