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, void *vobjp)
  49 {
  50         struct ocfs2_inode_handle *handle = vobjp;
  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);
  62
  63         if (IS_ERR(inode)) {
  64                 mlog_errno(PTR_ERR(inode));
  65                 return (void *)inode;
  66         }
  67
  68         if (handle->ih_generation != inode->i_generation) {
  69                 iput(inode);
  70                 mlog_errno(-ESTALE);
  71                 return ERR_PTR(-ESTALE);
  72         }
  73
  74         result = d_alloc_anon(inode);
  75
  76         if (!result) {
  77                 iput(inode);
  78                 mlog_errno(-ENOMEM);
  79                 return ERR_PTR(-ENOMEM);
  80         }
  81         result->d_op = &ocfs2_dentry_ops;
  82
  83         mlog_exit_ptr(result);
  84         return result;
  85 }
  86
  87 static struct dentry *ocfs2_get_parent(struct dentry *child)
  88 {
  89         int status;
  90         u64 blkno;
  91         struct dentry *parent;
  92         struct inode *inode;
  93         struct inode *dir = child->d_inode;
  94         struct buffer_head *dirent_bh = NULL;
  95         struct ocfs2_dir_entry *dirent;
  96
  97         mlog_entry("(0x%p, '%.*s')\n", child,
  98                    child->d_name.len, child->d_name.name);
  99
 100         mlog(0, "find parent of directory %llu\n",
 101              (unsigned long long)OCFS2_I(dir)->ip_blkno);
 102
 103         status = ocfs2_meta_lock(dir, NULL, NULL, 0);
 104         if (status < 0) {
 105                 if (status != -ENOENT)
 106                         mlog_errno(status);
 107                 parent = ERR_PTR(status);
 108                 goto bail;
 109         }
 110
 111         status = ocfs2_find_files_on_disk("..", 2, &blkno, dir, &dirent_bh,
 112                                           &dirent);
 113         if (status < 0) {
 114                 parent = ERR_PTR(-ENOENT);
 115                 goto bail_unlock;
 116         }
 117
 118         inode = ocfs2_iget(OCFS2_SB(dir->i_sb), blkno);
 119         if (IS_ERR(inode)) {
 120                 mlog(ML_ERROR, "Unable to create inode %llu\n",
 121                      (unsigned long long)blkno);
 122                 parent = ERR_PTR(-EACCES);
 123                 goto bail_unlock;
 124         }
 125
 126         parent = d_alloc_anon(inode);
 127         if (!parent) {
 128                 iput(inode);
 129                 parent = ERR_PTR(-ENOMEM);
 130         }
 131
 132         parent->d_op = &ocfs2_dentry_ops;
 133
 134 bail_unlock:
 135         ocfs2_meta_unlock(dir, 0);
 136
 137         if (dirent_bh)
 138                 brelse(dirent_bh);
 139
 140 bail:
 141         mlog_exit_ptr(parent);
 142
 143         return parent;
 144 }
 145
 146 static int ocfs2_encode_fh(struct dentry *dentry, __be32 *fh, int *max_len,
 147                            int connectable)
 148 {
 149         struct inode *inode = dentry->d_inode;
 150         int len = *max_len;
 151         int type = 1;
 152         u64 blkno;
 153         u32 generation;
 154
 155         mlog_entry("(0x%p, '%.*s', 0x%p, %d, %d)\n", dentry,
 156                    dentry->d_name.len, dentry->d_name.name,
 157                    fh, len, connectable);
 158
 159         if (len < 3 || (connectable && len < 6)) {
 160                 mlog(ML_ERROR, "fh buffer is too small for encoding\n");
 161                 type = 255;
 162                 goto bail;
 163         }
 164
 165         blkno = OCFS2_I(inode)->ip_blkno;
 166         generation = inode->i_generation;
 167
 168         mlog(0, "Encoding fh: blkno: %llu, generation: %u\n",
 169              (unsigned long long)blkno, generation);
 170
 171         len = 3;
 172         fh[0] = cpu_to_le32((u32)(blkno >> 32));
 173         fh[1] = cpu_to_le32((u32)(blkno & 0xffffffff));
 174         fh[2] = cpu_to_le32(generation);
 175
 176         if (connectable && !S_ISDIR(inode->i_mode)) {
 177                 struct inode *parent;
 178
 179                 spin_lock(&dentry->d_lock);
 180
 181                 parent = dentry->d_parent->d_inode;
 182                 blkno = OCFS2_I(parent)->ip_blkno;
 183                 generation = parent->i_generation;
 184
 185                 fh[3] = cpu_to_le32((u32)(blkno >> 32));
 186                 fh[4] = cpu_to_le32((u32)(blkno & 0xffffffff));
 187                 fh[5] = cpu_to_le32(generation);
 188
 189                 spin_unlock(&dentry->d_lock);
 190
 191                 len = 6;
 192                 type = 2;
 193
 194                 mlog(0, "Encoding parent: blkno: %llu, generation: %u\n",
 195                      (unsigned long long)blkno, generation);
 196         }
 197
 198         *max_len = len;
 199
 200 bail:
 201         mlog_exit(type);
 202         return type;
 203 }
 204
 205 static struct dentry *ocfs2_decode_fh(struct super_block *sb, __be32 *fh,
 206                                       int fh_len, int fileid_type,
 207                                       int (*acceptable)(void *context,
 208                                                         struct dentry *de),
 209                                       void *context)
 210 {
 211         struct ocfs2_inode_handle handle, parent;
 212         struct dentry *ret = NULL;
 213
 214         mlog_entry("(0x%p, 0x%p, %d, %d, 0x%p, 0x%p)\n",
 215                    sb, fh, fh_len, fileid_type, acceptable, context);
 216
 217         if (fh_len < 3 || fileid_type > 2)
 218                 goto bail;
 219
 220         if (fileid_type == 2) {
 221                 if (fh_len < 6)
 222                         goto bail;
 223
 224                 parent.ih_blkno = (u64)le32_to_cpu(fh[3]) << 32;
 225                 parent.ih_blkno |= (u64)le32_to_cpu(fh[4]);
 226                 parent.ih_generation = le32_to_cpu(fh[5]);
 227
 228                 mlog(0, "Decoding parent: blkno: %llu, generation: %u\n",
 229                      (unsigned long long)parent.ih_blkno,
 230                      parent.ih_generation);
 231         }
 232
 233         handle.ih_blkno = (u64)le32_to_cpu(fh[0]) << 32;
 234         handle.ih_blkno |= (u64)le32_to_cpu(fh[1]);
 235         handle.ih_generation = le32_to_cpu(fh[2]);
 236
 237         mlog(0, "Encoding fh: blkno: %llu, generation: %u\n",
 238              (unsigned long long)handle.ih_blkno, handle.ih_generation);
 239
 240         ret = ocfs2_export_ops.find_exported_dentry(sb, &handle, &parent,
 241                                                     acceptable, context);
 242
 243 bail:
 244         mlog_exit_ptr(ret);
 245         return ret;
 246 }
 247
 248 struct export_operations ocfs2_export_ops = {
 249         .decode_fh      = ocfs2_decode_fh,
 250         .encode_fh      = ocfs2_encode_fh,
 251
 252         .get_parent     = ocfs2_get_parent,
 253         .get_dentry     = ocfs2_get_dentry,
 254 };