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         /* CSTYLED */
  41         struct inode *ip = dentry->d_inode;
  42 #endif /* HAVE_ENCODE_FH_WITH_INODE */
  43         fstrans_cookie_t cookie;
  44         fid_t *fid = (fid_t *)fh;
  45         int len_bytes, rc;
  46
  47         len_bytes = *max_len * sizeof (__u32);
  48
  49         if (len_bytes < offsetof(fid_t, fid_data))
  50                 return (255);
  51
  52         fid->fid_len = len_bytes - offsetof(fid_t, fid_data);
  53         cookie = spl_fstrans_mark();
  54
  55         if (zfsctl_is_node(ip))
  56                 rc = zfsctl_fid(ip, fid);
  57         else
  58                 rc = zfs_fid(ip, fid);
  59
  60         spl_fstrans_unmark(cookie);
  61         len_bytes = offsetof(fid_t, fid_data) + fid->fid_len;
  62         *max_len = roundup(len_bytes, sizeof (__u32)) / sizeof (__u32);
  63
  64         return (rc == 0 ? FILEID_INO32_GEN : 255);
  65 }
  66
  67 static struct dentry *
  68 zpl_dentry_obtain_alias(struct inode *ip)
  69 {
  70         struct dentry *result;
  71
  72 #ifdef HAVE_D_OBTAIN_ALIAS
  73         result = d_obtain_alias(ip);
  74 #else
  75         result = d_alloc_anon(ip);
  76
  77         if (result == NULL) {
  78                 iput(ip);
  79                 result = ERR_PTR(-ENOMEM);
  80         }
  81 #endif /* HAVE_D_OBTAIN_ALIAS */
  82
  83         return (result);
  84 }
  85
  86 static struct dentry *
  87 zpl_fh_to_dentry(struct super_block *sb, struct fid *fh,
  88     int fh_len, int fh_type)
  89 {
  90         fid_t *fid = (fid_t *)fh;
  91         fstrans_cookie_t cookie;
  92         struct inode *ip;
  93         int len_bytes, rc;
  94
  95         len_bytes = fh_len * sizeof (__u32);
  96
  97         if (fh_type != FILEID_INO32_GEN ||
  98             len_bytes < offsetof(fid_t, fid_data) ||
  99             len_bytes < offsetof(fid_t, fid_data) + fid->fid_len)
 100                 return (ERR_PTR(-EINVAL));
 101
 102         cookie = spl_fstrans_mark();
 103         rc = zfs_vget(sb, &ip, fid);
 104         spl_fstrans_unmark(cookie);
 105
 106         if (rc) {
 107                 /*
 108                  * If we see ENOENT it might mean that an NFSv4 * client
 109                  * is using a cached inode value in a file handle and
 110                  * that the sought after file has had its inode changed
 111                  * by a third party.  So change the error to ESTALE
 112                  * which will trigger a full lookup by the client and
 113                  * will find the new filename/inode pair if it still
 114                  * exists.
 115                  */
 116                 if (rc == ENOENT)
 117                         rc = ESTALE;
 118
 119                 return (ERR_PTR(-rc));
 120         }
 121
 122         ASSERT((ip != NULL) && !IS_ERR(ip));
 123
 124         return (zpl_dentry_obtain_alias(ip));
 125 }
 126
 127 static struct dentry *
 128 zpl_get_parent(struct dentry *child)
 129 {
 130         cred_t *cr = CRED();
 131         fstrans_cookie_t cookie;
 132         struct inode *ip;
 133         int error;
 134
 135         crhold(cr);
 136         cookie = spl_fstrans_mark();
 137         error = -zfs_lookup(child->d_inode, "..", &ip, 0, cr, NULL, NULL);
 138         spl_fstrans_unmark(cookie);
 139         crfree(cr);
 140         ASSERT3S(error, <=, 0);
 141
 142         if (error)
 143                 return (ERR_PTR(error));
 144
 145         return (zpl_dentry_obtain_alias(ip));
 146 }
 147
 148 #ifdef HAVE_COMMIT_METADATA
 149 static int
 150 zpl_commit_metadata(struct inode *inode)
 151 {
 152         cred_t *cr = CRED();
 153         fstrans_cookie_t cookie;
 154         int error;
 155
 156         if (zfsctl_is_node(inode))
 157                 return (0);
 158
 159         crhold(cr);
 160         cookie = spl_fstrans_mark();
 161         error = -zfs_fsync(inode, 0, cr);
 162         spl_fstrans_unmark(cookie);
 163         crfree(cr);
 164         ASSERT3S(error, <=, 0);
 165
 166         return (error);
 167 }
 168 #endif /* HAVE_COMMIT_METADATA */
 169
 170 const struct export_operations zpl_export_operations = {
 171         .encode_fh              = zpl_encode_fh,
 172         .fh_to_dentry           = zpl_fh_to_dentry,
 173         .get_parent             = zpl_get_parent,
 174 #ifdef HAVE_COMMIT_METADATA
 175         .commit_metadata        = zpl_commit_metadata,
 176 #endif /* HAVE_COMMIT_METADATA */
 177 };