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 "alloc.h"
  35 #include "dir.h"
  36 #include "dlmglue.h"
  37 #include "dcache.h"
  38 #include "export.h"
  39 #include "inode.h"
  40
  41 #include "buffer_head_io.h"
  42 #include "suballoc.h"
  43
  44 struct ocfs2_inode_handle
  45 {
  46         u64 ih_blkno;
  47         u32 ih_generation;
  48 };
  49
  50 static struct dentry *ocfs2_get_dentry(struct super_block *sb,
  51                 struct ocfs2_inode_handle *handle)
  52 {
  53         struct inode *inode;
  54         struct ocfs2_super *osb = OCFS2_SB(sb);
  55         u64 blkno = handle->ih_blkno;
  56         int status, set;
  57         struct dentry *result;
  58
  59         mlog_entry("(0x%p, 0x%p)\n", sb, handle);
  60
  61         if (blkno == 0) {
  62                 mlog(0, "nfs wants inode with blkno: 0\n");
  63                 result = ERR_PTR(-ESTALE);
  64                 goto bail;
  65         }
  66
  67         inode = ocfs2_ilookup(sb, blkno);
  68         /*
  69          * If the inode exists in memory, we only need to check it's
  70          * generation number
  71          */
  72         if (inode)
  73                 goto check_gen;
  74
  75         /*
  76          * This will synchronize us against ocfs2_delete_inode() on
  77          * all nodes
  78          */
  79         status = ocfs2_nfs_sync_lock(osb, 1);
  80         if (status < 0) {
  81                 mlog(ML_ERROR, "getting nfs sync lock(EX) failed %d\n", status);
  82                 goto check_err;
  83         }
  84
  85         status = ocfs2_test_inode_bit(osb, blkno, &set);
  86         if (status < 0) {
  87                 if (status == -EINVAL) {
  88                         /*
  89                          * The blkno NFS gave us doesn't even show up
  90                          * as an inode, we return -ESTALE to be
  91                          * nice
  92                          */
  93                         mlog(0, "test inode bit failed %d\n", status);
  94                         status = -ESTALE;
  95                 } else {
  96                         mlog(ML_ERROR, "test inode bit failed %d\n", status);
  97                 }
  98                 goto unlock_nfs_sync;
  99         }
 100
 101         /* If the inode allocator bit is clear, this inode must be stale */
 102         if (!set) {
 103                 mlog(0, "inode %llu suballoc bit is clear\n",
 104                      (unsigned long long)blkno);
 105                 status = -ESTALE;
 106                 goto unlock_nfs_sync;
 107         }
 108
 109         inode = ocfs2_iget(osb, blkno, 0, 0);
 110
 111 unlock_nfs_sync:
 112         ocfs2_nfs_sync_unlock(osb, 1);
 113
 114 check_err:
 115         if (status < 0) {
 116                 if (status == -ESTALE) {
 117                         mlog(0, "stale inode ino: %llu generation: %u\n",
 118                              (unsigned long long)blkno, handle->ih_generation);
 119                 }
 120                 result = ERR_PTR(status);
 121                 goto bail;
 122         }
 123
 124         if (IS_ERR(inode)) {
 125                 mlog_errno(PTR_ERR(inode));
 126                 result = (void *)inode;
 127                 goto bail;
 128         }
 129
 130 check_gen:
 131         if (handle->ih_generation != inode->i_generation) {
 132                 iput(inode);
 133                 mlog(0, "stale inode ino: %llu generation: %u\n",
 134                      (unsigned long long)blkno, handle->ih_generation);
 135                 result = ERR_PTR(-ESTALE);
 136                 goto bail;
 137         }
 138
 139         result = d_obtain_alias(inode);
 140         if (IS_ERR(result))
 141                 mlog_errno(PTR_ERR(result));
 142
 143 bail:
 144         mlog_exit_ptr(result);
 145         return result;
 146 }
 147
 148 static struct dentry *ocfs2_get_parent(struct dentry *child)
 149 {
 150         int status;
 151         u64 blkno;
 152         struct dentry *parent;
 153         struct inode *dir = child->d_inode;
 154
 155         mlog_entry("(0x%p, '%.*s')\n", child,
 156                    child->d_name.len, child->d_name.name);
 157
 158         mlog(0, "find parent of directory %llu\n",
 159              (unsigned long long)OCFS2_I(dir)->ip_blkno);
 160
 161         status = ocfs2_inode_lock(dir, NULL, 0);
 162         if (status < 0) {
 163                 if (status != -ENOENT)
 164                         mlog_errno(status);
 165                 parent = ERR_PTR(status);
 166                 goto bail;
 167         }
 168
 169         status = ocfs2_lookup_ino_from_name(dir, "..", 2, &blkno);
 170         if (status < 0) {
 171                 parent = ERR_PTR(-ENOENT);
 172                 goto bail_unlock;
 173         }
 174
 175         parent = d_obtain_alias(ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0, 0));
 176
 177 bail_unlock:
 178         ocfs2_inode_unlock(dir, 0);
 179
 180 bail:
 181         mlog_exit_ptr(parent);
 182
 183         return parent;
 184 }
 185
 186 static int ocfs2_encode_fh(struct dentry *dentry, u32 *fh_in, int *max_len,
 187                            int connectable)
 188 {
 189         struct inode *inode = dentry->d_inode;
 190         int len = *max_len;
 191         int type = 1;
 192         u64 blkno;
 193         u32 generation;
 194         __le32 *fh = (__force __le32 *) fh_in;
 195
 196         mlog_entry("(0x%p, '%.*s', 0x%p, %d, %d)\n", dentry,
 197                    dentry->d_name.len, dentry->d_name.name,
 198                    fh, len, connectable);
 199
 200         if (len < 3 || (connectable && len < 6)) {
 201                 mlog(ML_ERROR, "fh buffer is too small for encoding\n");
 202                 type = 255;
 203                 goto bail;
 204         }
 205
 206         blkno = OCFS2_I(inode)->ip_blkno;
 207         generation = inode->i_generation;
 208
 209         mlog(0, "Encoding fh: blkno: %llu, generation: %u\n",
 210              (unsigned long long)blkno, generation);
 211
 212         len = 3;
 213         fh[0] = cpu_to_le32((u32)(blkno >> 32));
 214         fh[1] = cpu_to_le32((u32)(blkno & 0xffffffff));
 215         fh[2] = cpu_to_le32(generation);
 216
 217         if (connectable && !S_ISDIR(inode->i_mode)) {
 218                 struct inode *parent;
 219
 220                 spin_lock(&dentry->d_lock);
 221
 222                 parent = dentry->d_parent->d_inode;
 223                 blkno = OCFS2_I(parent)->ip_blkno;
 224                 generation = parent->i_generation;
 225
 226                 fh[3] = cpu_to_le32((u32)(blkno >> 32));
 227                 fh[4] = cpu_to_le32((u32)(blkno & 0xffffffff));
 228                 fh[5] = cpu_to_le32(generation);
 229
 230                 spin_unlock(&dentry->d_lock);
 231
 232                 len = 6;
 233                 type = 2;
 234
 235                 mlog(0, "Encoding parent: blkno: %llu, generation: %u\n",
 236                      (unsigned long long)blkno, generation);
 237         }
 238
 239         *max_len = len;
 240
 241 bail:
 242         mlog_exit(type);
 243         return type;
 244 }
 245
 246 static struct dentry *ocfs2_fh_to_dentry(struct super_block *sb,
 247                 struct fid *fid, int fh_len, int fh_type)
 248 {
 249         struct ocfs2_inode_handle handle;
 250
 251         if (fh_len < 3 || fh_type > 2)
 252                 return NULL;
 253
 254         handle.ih_blkno = (u64)le32_to_cpu(fid->raw[0]) << 32;
 255         handle.ih_blkno |= (u64)le32_to_cpu(fid->raw[1]);
 256         handle.ih_generation = le32_to_cpu(fid->raw[2]);
 257         return ocfs2_get_dentry(sb, &handle);
 258 }
 259
 260 static struct dentry *ocfs2_fh_to_parent(struct super_block *sb,
 261                 struct fid *fid, int fh_len, int fh_type)
 262 {
 263         struct ocfs2_inode_handle parent;
 264
 265         if (fh_type != 2 || fh_len < 6)
 266                 return NULL;
 267
 268         parent.ih_blkno = (u64)le32_to_cpu(fid->raw[3]) << 32;
 269         parent.ih_blkno |= (u64)le32_to_cpu(fid->raw[4]);
 270         parent.ih_generation = le32_to_cpu(fid->raw[5]);
 271         return ocfs2_get_dentry(sb, &parent);
 272 }
 273
 274 const struct export_operations ocfs2_export_ops = {
 275         .encode_fh      = ocfs2_encode_fh,
 276         .fh_to_dentry   = ocfs2_fh_to_dentry,
 277         .fh_to_parent   = ocfs2_fh_to_parent,
 278         .get_parent     = ocfs2_get_parent,
 279 };