fs/ocfs2/export.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * export.c
   5  *
   6  * Functions to facilitate NFS exporting
   7  *
   8  * Copyright (C) 2002, 2005 Oracle.  All rights reserved.
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public
  12  * License as published by the Free Software Foundation; either
  13  * version 2 of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public
  21  * License along with this program; if not, write to the
  22  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23  * Boston, MA 021110-1307, USA.
  24  */
  25
  26 #include <linux/fs.h>
  27 #include <linux/types.h>
  28
  29 #define MLOG_MASK_PREFIX ML_EXPORT
  30 #include <cluster/masklog.h>
  31
  32 #include "ocfs2.h"
  33
  34 #include "dir.h"
  35 #include "dlmglue.h"
  36 #include "dcache.h"
  37 #include "export.h"
  38 #include "inode.h"
  39
  40 #include "buffer_head_io.h"
  41
  42 struct ocfs2_inode_handle
  43 {
  44         u64 ih_blkno;
  45         u32 ih_generation;
  46 };
  47
  48 static struct dentry *ocfs2_get_dentry(struct super_block *sb,
  49                 struct ocfs2_inode_handle *handle)
  50 {
  51         struct inode *inode;
  52         struct dentry *result;
  53
  54         mlog_entry("(0x%p, 0x%p)\n", sb, handle);
  55
  56         if (handle->ih_blkno == 0) {
  57                 mlog_errno(-ESTALE);
  58                 return ERR_PTR(-ESTALE);
  59         }
  60
  61         inode = ocfs2_iget(OCFS2_SB(sb), handle->ih_blkno, 0, 0);
  62
  63         if (IS_ERR(inode))
  64                 return (void *)inode;
  65
  66         if (handle->ih_generation != inode->i_generation) {
  67                 iput(inode);
  68                 return ERR_PTR(-ESTALE);
  69         }
  70
  71         result = d_obtain_alias(inode);
  72         if (!IS_ERR(result))
  73                 result->d_op = &ocfs2_dentry_ops;
  74
  75         mlog_exit_ptr(result);
  76         return result;
  77 }
  78
  79 static struct dentry *ocfs2_get_parent(struct dentry *child)
  80 {
  81         int status;
  82         u64 blkno;
  83         struct dentry *parent;
  84         struct inode *dir = child->d_inode;
  85
  86         mlog_entry("(0x%p, '%.*s')\n", child,
  87                    child->d_name.len, child->d_name.name);
  88
  89         mlog(0, "find parent of directory %llu\n",
  90              (unsigned long long)OCFS2_I(dir)->ip_blkno);
  91
  92         status = ocfs2_inode_lock(dir, NULL, 0);
  93         if (status < 0) {
  94                 if (status != -ENOENT)
  95                         mlog_errno(status);
  96                 parent = ERR_PTR(status);
  97                 goto bail;
  98         }
  99
 100         status = ocfs2_lookup_ino_from_name(dir, "..", 2, &blkno);
 101         if (status < 0) {
 102                 parent = ERR_PTR(-ENOENT);
 103                 goto bail_unlock;
 104         }
 105
 106         parent = d_obtain_alias(ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0, 0));
 107         if (!IS_ERR(parent))
 108                 parent->d_op = &ocfs2_dentry_ops;
 109
 110 bail_unlock:
 111         ocfs2_inode_unlock(dir, 0);
 112
 113 bail:
 114         mlog_exit_ptr(parent);
 115
 116         return parent;
 117 }
 118
 119 static int ocfs2_encode_fh(struct dentry *dentry, u32 *fh_in, int *max_len,
 120                            int connectable)
 121 {
 122         struct inode *inode = dentry->d_inode;
 123         int len = *max_len;
 124         int type = 1;
 125         u64 blkno;
 126         u32 generation;
 127         __le32 *fh = (__force __le32 *) fh_in;
 128
 129         mlog_entry("(0x%p, '%.*s', 0x%p, %d, %d)\n", dentry,
 130                    dentry->d_name.len, dentry->d_name.name,
 131                    fh, len, connectable);
 132
 133         if (len < 3 || (connectable && len < 6)) {
 134                 mlog(ML_ERROR, "fh buffer is too small for encoding\n");
 135                 type = 255;
 136                 goto bail;
 137         }
 138
 139         blkno = OCFS2_I(inode)->ip_blkno;
 140         generation = inode->i_generation;
 141
 142         mlog(0, "Encoding fh: blkno: %llu, generation: %u\n",
 143              (unsigned long long)blkno, generation);
 144
 145         len = 3;
 146         fh[0] = cpu_to_le32((u32)(blkno >> 32));
 147         fh[1] = cpu_to_le32((u32)(blkno & 0xffffffff));
 148         fh[2] = cpu_to_le32(generation);
 149
 150         if (connectable && !S_ISDIR(inode->i_mode)) {
 151                 struct inode *parent;
 152
 153                 spin_lock(&dentry->d_lock);
 154
 155                 parent = dentry->d_parent->d_inode;
 156                 blkno = OCFS2_I(parent)->ip_blkno;
 157                 generation = parent->i_generation;
 158
 159                 fh[3] = cpu_to_le32((u32)(blkno >> 32));
 160                 fh[4] = cpu_to_le32((u32)(blkno & 0xffffffff));
 161                 fh[5] = cpu_to_le32(generation);
 162
 163                 spin_unlock(&dentry->d_lock);
 164
 165                 len = 6;
 166                 type = 2;
 167
 168                 mlog(0, "Encoding parent: blkno: %llu, generation: %u\n",
 169                      (unsigned long long)blkno, generation);
 170         }
 171
 172         *max_len = len;
 173
 174 bail:
 175         mlog_exit(type);
 176         return type;
 177 }
 178
 179 static struct dentry *ocfs2_fh_to_dentry(struct super_block *sb,
 180                 struct fid *fid, int fh_len, int fh_type)
 181 {
 182         struct ocfs2_inode_handle handle;
 183
 184         if (fh_len < 3 || fh_type > 2)
 185                 return NULL;
 186
 187         handle.ih_blkno = (u64)le32_to_cpu(fid->raw[0]) << 32;
 188         handle.ih_blkno |= (u64)le32_to_cpu(fid->raw[1]);
 189         handle.ih_generation = le32_to_cpu(fid->raw[2]);
 190         return ocfs2_get_dentry(sb, &handle);
 191 }
 192
 193 static struct dentry *ocfs2_fh_to_parent(struct super_block *sb,
 194                 struct fid *fid, int fh_len, int fh_type)
 195 {
 196         struct ocfs2_inode_handle parent;
 197
 198         if (fh_type != 2 || fh_len < 6)
 199                 return NULL;
 200
 201         parent.ih_blkno = (u64)le32_to_cpu(fid->raw[3]) << 32;
 202         parent.ih_blkno |= (u64)le32_to_cpu(fid->raw[4]);
 203         parent.ih_generation = le32_to_cpu(fid->raw[5]);
 204         return ocfs2_get_dentry(sb, &parent);
 205 }
 206
 207 const struct export_operations ocfs2_export_ops = {
 208         .encode_fh      = ocfs2_encode_fh,
 209         .fh_to_dentry   = ocfs2_fh_to_dentry,
 210         .fh_to_parent   = ocfs2_fh_to_parent,
 211         .get_parent     = ocfs2_get_parent,
 212 };