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