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 "export.h"
  37 #include "inode.h"
  38
  39 #include "buffer_head_io.h"
  40
  41 struct ocfs2_inode_handle
  42 {
  43         u64 ih_blkno;
  44         u32 ih_generation;
  45 };
  46
  47 static struct dentry *ocfs2_get_dentry(struct super_block *sb, void *vobjp)
  48 {
  49         struct ocfs2_inode_handle *handle = vobjp;
  50         struct inode *inode;
  51         struct dentry *result;
  52
  53         mlog_entry("(0x%p, 0x%p)\n", sb, handle);
  54
  55         if (handle->ih_blkno == 0) {
  56                 mlog_errno(-ESTALE);
  57                 return ERR_PTR(-ESTALE);
  58         }
  59
  60         inode = ocfs2_iget(OCFS2_SB(sb), handle->ih_blkno);
  61
  62         if (IS_ERR(inode)) {
  63                 mlog_errno(PTR_ERR(inode));
  64                 return (void *)inode;
  65         }
  66
  67         if (handle->ih_generation != inode->i_generation) {
  68                 iput(inode);
  69                 mlog_errno(-ESTALE);
  70                 return ERR_PTR(-ESTALE);
  71         }
  72
  73         result = d_alloc_anon(inode);
  74
  75         if (!result) {
  76                 iput(inode);
  77                 mlog_errno(-ENOMEM);
  78                 return ERR_PTR(-ENOMEM);
  79         }
  80
  81         mlog_exit_ptr(result);
  82         return result;
  83 }
  84
  85 static struct dentry *ocfs2_get_parent(struct dentry *child)
  86 {
  87         int status;
  88         u64 blkno;
  89         struct dentry *parent;
  90         struct inode *inode;
  91         struct inode *dir = child->d_inode;
  92         struct buffer_head *dirent_bh = NULL;
  93         struct ocfs2_dir_entry *dirent;
  94
  95         mlog_entry("(0x%p, '%.*s')\n", child,
  96                    child->d_name.len, child->d_name.name);
  97
  98         mlog(0, "find parent of directory %"MLFu64"\n",
  99              OCFS2_I(dir)->ip_blkno);
 100
 101         status = ocfs2_meta_lock(dir, NULL, NULL, 0);
 102         if (status < 0) {
 103                 if (status != -ENOENT)
 104                         mlog_errno(status);
 105                 parent = ERR_PTR(status);
 106                 goto bail;
 107         }
 108
 109         status = ocfs2_find_files_on_disk("..", 2, &blkno, dir, &dirent_bh,
 110                                           &dirent);
 111         if (status < 0) {
 112                 parent = ERR_PTR(-ENOENT);
 113                 goto bail_unlock;
 114         }
 115
 116         inode = ocfs2_iget(OCFS2_SB(dir->i_sb), blkno);
 117         if (IS_ERR(inode)) {
 118                 mlog(ML_ERROR, "Unable to create inode %"MLFu64"\n", blkno);
 119                 parent = ERR_PTR(-EACCES);
 120                 goto bail_unlock;
 121         }
 122
 123         parent = d_alloc_anon(inode);
 124         if (!parent) {
 125                 iput(inode);
 126                 parent = ERR_PTR(-ENOMEM);
 127         }
 128
 129 bail_unlock:
 130         ocfs2_meta_unlock(dir, 0);
 131
 132         if (dirent_bh)
 133                 brelse(dirent_bh);
 134
 135 bail:
 136         mlog_exit_ptr(parent);
 137
 138         return parent;
 139 }
 140
 141 static int ocfs2_encode_fh(struct dentry *dentry, __be32 *fh, int *max_len,
 142                            int connectable)
 143 {
 144         struct inode *inode = dentry->d_inode;
 145         int len = *max_len;
 146         int type = 1;
 147         u64 blkno;
 148         u32 generation;
 149
 150         mlog_entry("(0x%p, '%.*s', 0x%p, %d, %d)\n", dentry,
 151                    dentry->d_name.len, dentry->d_name.name,
 152                    fh, len, connectable);
 153
 154         if (len < 3 || (connectable && len < 6)) {
 155                 mlog(ML_ERROR, "fh buffer is too small for encoding\n");
 156                 type = 255;
 157                 goto bail;
 158         }
 159
 160         blkno = OCFS2_I(inode)->ip_blkno;
 161         generation = inode->i_generation;
 162
 163         mlog(0, "Encoding fh: blkno: %"MLFu64", generation: %u\n",
 164              blkno, generation);
 165
 166         len = 3;
 167         fh[0] = cpu_to_le32((u32)(blkno >> 32));
 168         fh[1] = cpu_to_le32((u32)(blkno & 0xffffffff));
 169         fh[2] = cpu_to_le32(generation);
 170
 171         if (connectable && !S_ISDIR(inode->i_mode)) {
 172                 struct inode *parent;
 173
 174                 spin_lock(&dentry->d_lock);
 175
 176                 parent = dentry->d_parent->d_inode;
 177                 blkno = OCFS2_I(parent)->ip_blkno;
 178                 generation = parent->i_generation;
 179
 180                 fh[3] = cpu_to_le32((u32)(blkno >> 32));
 181                 fh[4] = cpu_to_le32((u32)(blkno & 0xffffffff));
 182                 fh[5] = cpu_to_le32(generation);
 183
 184                 spin_unlock(&dentry->d_lock);
 185
 186                 len = 6;
 187                 type = 2;
 188
 189                 mlog(0, "Encoding parent: blkno: %"MLFu64", generation: %u\n",
 190                      blkno, generation);
 191         }
 192
 193         *max_len = len;
 194
 195 bail:
 196         mlog_exit(type);
 197         return type;
 198 }
 199
 200 static struct dentry *ocfs2_decode_fh(struct super_block *sb, __be32 *fh,
 201                                       int fh_len, int fileid_type,
 202                                       int (*acceptable)(void *context,
 203                                                         struct dentry *de),
 204                                       void *context)
 205 {
 206         struct ocfs2_inode_handle handle, parent;
 207         struct dentry *ret = NULL;
 208
 209         mlog_entry("(0x%p, 0x%p, %d, %d, 0x%p, 0x%p)\n",
 210                    sb, fh, fh_len, fileid_type, acceptable, context);
 211
 212         if (fh_len < 3 || fileid_type > 2)
 213                 goto bail;
 214
 215         if (fileid_type == 2) {
 216                 if (fh_len < 6)
 217                         goto bail;
 218
 219                 parent.ih_blkno = (u64)le32_to_cpu(fh[3]) << 32;
 220                 parent.ih_blkno |= (u64)le32_to_cpu(fh[4]);
 221                 parent.ih_generation = le32_to_cpu(fh[5]);
 222
 223                 mlog(0, "Decoding parent: blkno: %"MLFu64", generation: %u\n",
 224                      parent.ih_blkno, parent.ih_generation);
 225         }
 226
 227         handle.ih_blkno = (u64)le32_to_cpu(fh[0]) << 32;
 228         handle.ih_blkno |= (u64)le32_to_cpu(fh[1]);
 229         handle.ih_generation = le32_to_cpu(fh[2]);
 230
 231         mlog(0, "Encoding fh: blkno: %"MLFu64", generation: %u\n",
 232              handle.ih_blkno, handle.ih_generation);
 233
 234         ret = ocfs2_export_ops.find_exported_dentry(sb, &handle, &parent,
 235                                                     acceptable, context);
 236
 237 bail:
 238         mlog_exit_ptr(ret);
 239         return ret;
 240 }
 241
 242 struct export_operations ocfs2_export_ops = {
 243         .decode_fh      = ocfs2_decode_fh,
 244         .encode_fh      = ocfs2_encode_fh,
 245
 246         .get_parent     = ocfs2_get_parent,
 247         .get_dentry     = ocfs2_get_dentry,
 248 };