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  * Copyright (c) 2012 Cyril Plisko. All rights reserved.
  24  */
  25
  26
  27 #include <sys/zfs_vnops.h>
  28 #include <sys/zfs_znode.h>
  29 #include <sys/zfs_ctldir.h>
  30 #include <sys/zpl.h>
  31
  32
  33 static int
  34 #ifdef HAVE_ENCODE_FH_WITH_INODE
  35 zpl_encode_fh(struct inode *ip, __u32 *fh, int *max_len, struct inode *parent)
  36 {
  37 #else
  38 zpl_encode_fh(struct dentry *dentry, __u32 *fh, int *max_len, int connectable)
  39 {
  40         struct inode *ip = dentry->d_inode;
  41 #endif /* HAVE_ENCODE_FH_WITH_INODE */
  42         fid_t *fid = (fid_t *)fh;
  43         int len_bytes, rc;
  44
  45         len_bytes = *max_len * sizeof (__u32);
  46
  47         if (len_bytes < offsetof(fid_t, fid_data))
  48                 return 255;
  49
  50         fid->fid_len = len_bytes - offsetof(fid_t, fid_data);
  51
  52         if (zfsctl_is_node(ip))
  53                 rc = zfsctl_fid(ip, fid);
  54         else
  55                 rc = zfs_fid(ip, fid);
  56
  57         len_bytes = offsetof(fid_t, fid_data) + fid->fid_len;
  58         *max_len = roundup(len_bytes, sizeof (__u32)) / sizeof (__u32);
  59
  60         return (rc == 0 ? FILEID_INO32_GEN : 255);
  61 }
  62
  63 static struct dentry *
  64 zpl_dentry_obtain_alias(struct inode *ip)
  65 {
  66         struct dentry *result;
  67
  68 #ifdef HAVE_D_OBTAIN_ALIAS
  69         result = d_obtain_alias(ip);
  70 #else
  71         result = d_alloc_anon(ip);
  72
  73         if (result == NULL) {
  74                 iput(ip);
  75                 result = ERR_PTR(-ENOMEM);
  76         }
  77 #endif /* HAVE_D_OBTAIN_ALIAS */
  78
  79         return result;
  80 }
  81
  82 static struct dentry *
  83 zpl_fh_to_dentry(struct super_block *sb, struct fid *fh,
  84     int fh_len, int fh_type)
  85 {
  86         fid_t *fid = (fid_t *)fh;
  87         struct inode *ip;
  88         int len_bytes, rc;
  89
  90         len_bytes = fh_len * sizeof (__u32);
  91
  92         if (fh_type != FILEID_INO32_GEN ||
  93             len_bytes < offsetof(fid_t, fid_data) ||
  94             len_bytes < offsetof(fid_t, fid_data) + fid->fid_len)
  95                 return ERR_PTR(-EINVAL);
  96
  97         rc = zfs_vget(sb, &ip, fid);
  98
  99         if (rc != 0)
 100                 return ERR_PTR(-rc);
 101
 102         ASSERT((ip != NULL) && !IS_ERR(ip));
 103
 104         return zpl_dentry_obtain_alias(ip);
 105 }
 106
 107 static struct dentry *
 108 zpl_get_parent(struct dentry *child)
 109 {
 110         cred_t *cr = CRED();
 111         struct inode *ip;
 112         int error;
 113
 114         crhold(cr);
 115         error = -zfs_lookup(child->d_inode, "..", &ip, 0, cr, NULL, NULL);
 116         crfree(cr);
 117         ASSERT3S(error, <=, 0);
 118
 119         if (error)
 120                 return ERR_PTR(error);
 121
 122         return zpl_dentry_obtain_alias(ip);
 123 }
 124
 125 #ifdef HAVE_COMMIT_METADATA
 126 static int
 127 zpl_commit_metadata(struct inode *inode)
 128 {
 129         cred_t *cr = CRED();
 130         int error;
 131
 132         crhold(cr);
 133         error = -zfs_fsync(inode, 0, cr);
 134         crfree(cr);
 135         ASSERT3S(error, <=, 0);
 136
 137         return error;
 138 }
 139 #endif /* HAVE_COMMIT_METADATA */
 140
 141 const struct export_operations zpl_export_operations = {
 142         .encode_fh      = zpl_encode_fh,
 143         .fh_to_dentry   = zpl_fh_to_dentry,
 144         .get_parent     = zpl_get_parent,
 145 #ifdef HAVE_COMMIT_METADATA
 146         .commit_metadata= zpl_commit_metadata,
 147 #endif /* HAVE_COMMIT_METADATA */
 148 };