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