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 #include <cluster/masklog.h>
  30
  31 #include "ocfs2.h"
  32
  33 #include "alloc.h"
  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 #include "suballoc.h"
  42 #include "ocfs2_trace.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         trace_ocfs2_get_dentry_begin(sb, handle, (unsigned long long)blkno);
  60
  61         if (blkno == 0) {
  62                 result = ERR_PTR(-ESTALE);
  63                 goto bail;
  64         }
  65
  66         inode = ocfs2_ilookup(sb, blkno);
  67         /*
  68          * If the inode exists in memory, we only need to check it's
  69          * generation number
  70          */
  71         if (inode)
  72                 goto check_gen;
  73
  74         /*
  75          * This will synchronize us against ocfs2_delete_inode() on
  76          * all nodes
  77          */
  78         status = ocfs2_nfs_sync_lock(osb, 1);
  79         if (status < 0) {
  80                 mlog(ML_ERROR, "getting nfs sync lock(EX) failed %d\n", status);
  81                 goto check_err;
  82         }
  83
  84         status = ocfs2_test_inode_bit(osb, blkno, &set);
  85         trace_ocfs2_get_dentry_test_bit(status, 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                         status = -ESTALE;
  94                 } else
  95                         mlog(ML_ERROR, "test inode bit failed %d\n", status);
  96                 goto unlock_nfs_sync;
  97         }
  98
  99         /* If the inode allocator bit is clear, this inode must be stale */
 100         if (!set) {
 101                 status = -ESTALE;
 102                 goto unlock_nfs_sync;
 103         }
 104
 105         inode = ocfs2_iget(osb, blkno, 0, 0);
 106
 107 unlock_nfs_sync:
 108         ocfs2_nfs_sync_unlock(osb, 1);
 109
 110 check_err:
 111         if (status < 0) {
 112                 if (status == -ESTALE) {
 113                         trace_ocfs2_get_dentry_stale((unsigned long long)blkno,
 114                                                      handle->ih_generation);
 115                 }
 116                 result = ERR_PTR(status);
 117                 goto bail;
 118         }
 119
 120         if (IS_ERR(inode)) {
 121                 mlog_errno(PTR_ERR(inode));
 122                 result = (void *)inode;
 123                 goto bail;
 124         }
 125
 126 check_gen:
 127         if (handle->ih_generation != inode->i_generation) {
 128                 iput(inode);
 129                 trace_ocfs2_get_dentry_generation((unsigned long long)blkno,
 130                                                   handle->ih_generation,
 131                                                   inode->i_generation);
 132                 result = ERR_PTR(-ESTALE);
 133                 goto bail;
 134         }
 135
 136         result = d_obtain_alias(inode);
 137         if (IS_ERR(result))
 138                 mlog_errno(PTR_ERR(result));
 139
 140 bail:
 141         trace_ocfs2_get_dentry_end(result);
 142         return result;
 143 }
 144
 145 static struct dentry *ocfs2_get_parent(struct dentry *child)
 146 {
 147         int status;
 148         u64 blkno;
 149         struct dentry *parent;
 150         struct inode *dir = child->d_inode;
 151
 152         trace_ocfs2_get_parent(child, child->d_name.len, child->d_name.name,
 153                                (unsigned long long)OCFS2_I(dir)->ip_blkno);
 154
 155         status = ocfs2_inode_lock(dir, NULL, 0);
 156         if (status < 0) {
 157                 if (status != -ENOENT)
 158                         mlog_errno(status);
 159                 parent = ERR_PTR(status);
 160                 goto bail;
 161         }
 162
 163         status = ocfs2_lookup_ino_from_name(dir, "..", 2, &blkno);
 164         if (status < 0) {
 165                 parent = ERR_PTR(-ENOENT);
 166                 goto bail_unlock;
 167         }
 168
 169         parent = d_obtain_alias(ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0, 0));
 170
 171 bail_unlock:
 172         ocfs2_inode_unlock(dir, 0);
 173
 174 bail:
 175         trace_ocfs2_get_parent_end(parent);
 176
 177         return parent;
 178 }
 179
 180 static int ocfs2_encode_fh(struct dentry *dentry, u32 *fh_in, int *max_len,
 181                            int connectable)
 182 {
 183         struct inode *inode = dentry->d_inode;
 184         int len = *max_len;
 185         int type = 1;
 186         u64 blkno;
 187         u32 generation;
 188         __le32 *fh = (__force __le32 *) fh_in;
 189
 190         trace_ocfs2_encode_fh_begin(dentry, dentry->d_name.len,
 191                                     dentry->d_name.name,
 192                                     fh, len, connectable);
 193
 194         if (connectable && (len < 6)) {
 195                 *max_len = 6;
 196                 type = 255;
 197                 goto bail;
 198         } else if (len < 3) {
 199                 *max_len = 3;
 200                 type = 255;
 201                 goto bail;
 202         }
 203
 204         blkno = OCFS2_I(inode)->ip_blkno;
 205         generation = inode->i_generation;
 206
 207         trace_ocfs2_encode_fh_self((unsigned long long)blkno, generation);
 208
 209         len = 3;
 210         fh[0] = cpu_to_le32((u32)(blkno >> 32));
 211         fh[1] = cpu_to_le32((u32)(blkno & 0xffffffff));
 212         fh[2] = cpu_to_le32(generation);
 213
 214         if (connectable && !S_ISDIR(inode->i_mode)) {
 215                 struct inode *parent;
 216
 217                 spin_lock(&dentry->d_lock);
 218
 219                 parent = dentry->d_parent->d_inode;
 220                 blkno = OCFS2_I(parent)->ip_blkno;
 221                 generation = parent->i_generation;
 222
 223                 fh[3] = cpu_to_le32((u32)(blkno >> 32));
 224                 fh[4] = cpu_to_le32((u32)(blkno & 0xffffffff));
 225                 fh[5] = cpu_to_le32(generation);
 226
 227                 spin_unlock(&dentry->d_lock);
 228
 229                 len = 6;
 230                 type = 2;
 231
 232                 trace_ocfs2_encode_fh_parent((unsigned long long)blkno,
 233                                              generation);
 234         }
 235
 236         *max_len = len;
 237
 238 bail:
 239         trace_ocfs2_encode_fh_type(type);
 240         return type;
 241 }
 242
 243 static struct dentry *ocfs2_fh_to_dentry(struct super_block *sb,
 244                 struct fid *fid, int fh_len, int fh_type)
 245 {
 246         struct ocfs2_inode_handle handle;
 247
 248         if (fh_len < 3 || fh_type > 2)
 249                 return NULL;
 250
 251         handle.ih_blkno = (u64)le32_to_cpu(fid->raw[0]) << 32;
 252         handle.ih_blkno |= (u64)le32_to_cpu(fid->raw[1]);
 253         handle.ih_generation = le32_to_cpu(fid->raw[2]);
 254         return ocfs2_get_dentry(sb, &handle);
 255 }
 256
 257 static struct dentry *ocfs2_fh_to_parent(struct super_block *sb,
 258                 struct fid *fid, int fh_len, int fh_type)
 259 {
 260         struct ocfs2_inode_handle parent;
 261
 262         if (fh_type != 2 || fh_len < 6)
 263                 return NULL;
 264
 265         parent.ih_blkno = (u64)le32_to_cpu(fid->raw[3]) << 32;
 266         parent.ih_blkno |= (u64)le32_to_cpu(fid->raw[4]);
 267         parent.ih_generation = le32_to_cpu(fid->raw[5]);
 268         return ocfs2_get_dentry(sb, &parent);
 269 }
 270
 271 const struct export_operations ocfs2_export_ops = {
 272         .encode_fh      = ocfs2_encode_fh,
 273         .fh_to_dentry   = ocfs2_fh_to_dentry,
 274         .fh_to_parent   = ocfs2_fh_to_parent,
 275         .get_parent     = ocfs2_get_parent,
 276 };