module/os/linux/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_znode.h>
  28 #include <sys/zfs_vnops.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         ushort_t empty_fid = 0;
  45         fid_t *fid;
  46         int len_bytes, rc;
  47
  48         len_bytes = *max_len * sizeof (__u32);
  49
  50         if (len_bytes < offsetof(fid_t, fid_data)) {
  51                 fid = (fid_t *)&empty_fid;
  52         } else {
  53                 fid = (fid_t *)fh;
  54                 fid->fid_len = len_bytes - offsetof(fid_t, fid_data);
  55         }
  56
  57         cookie = spl_fstrans_mark();
  58
  59         if (zfsctl_is_node(ip))
  60                 rc = zfsctl_fid(ip, fid);
  61         else
  62                 rc = zfs_fid(ip, fid);
  63
  64         spl_fstrans_unmark(cookie);
  65         len_bytes = offsetof(fid_t, fid_data) + fid->fid_len;
  66         *max_len = roundup(len_bytes, sizeof (__u32)) / sizeof (__u32);
  67
  68         return (rc == 0 ? FILEID_INO32_GEN : 255);
  69 }
  70
  71 static struct dentry *
  72 zpl_fh_to_dentry(struct super_block *sb, struct fid *fh,
  73     int fh_len, int fh_type)
  74 {
  75         fid_t *fid = (fid_t *)fh;
  76         fstrans_cookie_t cookie;
  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         cookie = spl_fstrans_mark();
  88         rc = zfs_vget(sb, &ip, fid);
  89         spl_fstrans_unmark(cookie);
  90
  91         if (rc) {
  92                 /*
  93                  * If we see ENOENT it might mean that an NFSv4 * client
  94                  * is using a cached inode value in a file handle and
  95                  * that the sought after file has had its inode changed
  96                  * by a third party.  So change the error to ESTALE
  97                  * which will trigger a full lookup by the client and
  98                  * will find the new filename/inode pair if it still
  99                  * exists.
 100                  */
 101                 if (rc == ENOENT)
 102                         rc = ESTALE;
 103
 104                 return (ERR_PTR(-rc));
 105         }
 106
 107         ASSERT((ip != NULL) && !IS_ERR(ip));
 108
 109         return (d_obtain_alias(ip));
 110 }
 111
 112 static struct dentry *
 113 zpl_get_parent(struct dentry *child)
 114 {
 115         cred_t *cr = CRED();
 116         fstrans_cookie_t cookie;
 117         znode_t *zp;
 118         int error;
 119
 120         crhold(cr);
 121         cookie = spl_fstrans_mark();
 122         error = -zfs_lookup(ITOZ(child->d_inode), "..", &zp, 0, cr, NULL, NULL);
 123         spl_fstrans_unmark(cookie);
 124         crfree(cr);
 125         ASSERT3S(error, <=, 0);
 126
 127         if (error)
 128                 return (ERR_PTR(error));
 129
 130         return (d_obtain_alias(ZTOI(zp)));
 131 }
 132
 133 static int
 134 zpl_commit_metadata(struct inode *inode)
 135 {
 136         cred_t *cr = CRED();
 137         fstrans_cookie_t cookie;
 138         int error;
 139
 140         if (zfsctl_is_node(inode))
 141                 return (0);
 142
 143         crhold(cr);
 144         cookie = spl_fstrans_mark();
 145         error = -zfs_fsync(ITOZ(inode), 0, cr);
 146         spl_fstrans_unmark(cookie);
 147         crfree(cr);
 148         ASSERT3S(error, <=, 0);
 149
 150         return (error);
 151 }
 152
 153 const struct export_operations zpl_export_operations = {
 154         .encode_fh              = zpl_encode_fh,
 155         .fh_to_dentry           = zpl_fh_to_dentry,
 156         .get_parent             = zpl_get_parent,
 157         .commit_metadata        = zpl_commit_metadata,
 158 };