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         if (status < 0) {
  86                 if (status == -EINVAL) {
  87                         /*
  88                          * The blkno NFS gave us doesn't even show up
  89                          * as an inode, we return -ESTALE to be
  90                          * nice
  91                          */
  92                         status = -ESTALE;
  93                 } else
  94                         mlog(ML_ERROR, "test inode bit failed %d\n", status);
  95                 goto unlock_nfs_sync;
  96         }
  97
  98         trace_ocfs2_get_dentry_test_bit(status, set);
  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 = ERR_CAST(inode);
 123                 goto bail;
 124         }
 125
 126 check_gen:
 127         if (handle->ih_generation != inode->i_generation) {
 128                 trace_ocfs2_get_dentry_generation((unsigned long long)blkno,
 129                                                   handle->ih_generation,
 130                                                   inode->i_generation);
 131                 iput(inode);
 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 = d_inode(child);
 151         int set;
 152
 153         trace_ocfs2_get_parent(child, child->d_name.len, child->d_name.name,
 154                                (unsigned long long)OCFS2_I(dir)->ip_blkno);
 155
 156         status = ocfs2_nfs_sync_lock(OCFS2_SB(dir->i_sb), 1);
 157         if (status < 0) {
 158                 mlog(ML_ERROR, "getting nfs sync lock(EX) failed %d\n", status);
 159                 parent = ERR_PTR(status);
 160                 goto bail;
 161         }
 162
 163         status = ocfs2_inode_lock(dir, NULL, 0);
 164         if (status < 0) {
 165                 if (status != -ENOENT)
 166                         mlog_errno(status);
 167                 parent = ERR_PTR(status);
 168                 goto unlock_nfs_sync;
 169         }
 170
 171         status = ocfs2_lookup_ino_from_name(dir, "..", 2, &blkno);
 172         if (status < 0) {
 173                 parent = ERR_PTR(-ENOENT);
 174                 goto bail_unlock;
 175         }
 176
 177         status = ocfs2_test_inode_bit(OCFS2_SB(dir->i_sb), blkno, &set);
 178         if (status < 0) {
 179                 if (status == -EINVAL) {
 180                         status = -ESTALE;
 181                 } else
 182                         mlog(ML_ERROR, "test inode bit failed %d\n", status);
 183                 parent = ERR_PTR(status);
 184                 goto bail_unlock;
 185         }
 186
 187         trace_ocfs2_get_dentry_test_bit(status, set);
 188         if (!set) {
 189                 status = -ESTALE;
 190                 parent = ERR_PTR(status);
 191                 goto bail_unlock;
 192         }
 193
 194         parent = d_obtain_alias(ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0, 0));
 195
 196 bail_unlock:
 197         ocfs2_inode_unlock(dir, 0);
 198
 199 unlock_nfs_sync:
 200         ocfs2_nfs_sync_unlock(OCFS2_SB(dir->i_sb), 1);
 201
 202 bail:
 203         trace_ocfs2_get_parent_end(parent);
 204
 205         return parent;
 206 }
 207
 208 static int ocfs2_encode_fh(struct inode *inode, u32 *fh_in, int *max_len,
 209                            struct inode *parent)
 210 {
 211         int len = *max_len;
 212         int type = 1;
 213         u64 blkno;
 214         u32 generation;
 215         __le32 *fh = (__force __le32 *) fh_in;
 216
 217 #ifdef TRACE_HOOKS_ARE_NOT_BRAINDEAD_IN_YOUR_OPINION
 218 #error "You go ahead and fix that mess, then.  Somehow"
 219         trace_ocfs2_encode_fh_begin(dentry, dentry->d_name.len,
 220                                     dentry->d_name.name,
 221                                     fh, len, connectable);
 222 #endif
 223
 224         if (parent && (len < 6)) {
 225                 *max_len = 6;
 226                 type = FILEID_INVALID;
 227                 goto bail;
 228         } else if (len < 3) {
 229                 *max_len = 3;
 230                 type = FILEID_INVALID;
 231                 goto bail;
 232         }
 233
 234         blkno = OCFS2_I(inode)->ip_blkno;
 235         generation = inode->i_generation;
 236
 237         trace_ocfs2_encode_fh_self((unsigned long long)blkno, generation);
 238
 239         len = 3;
 240         fh[0] = cpu_to_le32((u32)(blkno >> 32));
 241         fh[1] = cpu_to_le32((u32)(blkno & 0xffffffff));
 242         fh[2] = cpu_to_le32(generation);
 243
 244         if (parent) {
 245                 blkno = OCFS2_I(parent)->ip_blkno;
 246                 generation = parent->i_generation;
 247
 248                 fh[3] = cpu_to_le32((u32)(blkno >> 32));
 249                 fh[4] = cpu_to_le32((u32)(blkno & 0xffffffff));
 250                 fh[5] = cpu_to_le32(generation);
 251
 252                 len = 6;
 253                 type = 2;
 254
 255                 trace_ocfs2_encode_fh_parent((unsigned long long)blkno,
 256                                              generation);
 257         }
 258
 259         *max_len = len;
 260
 261 bail:
 262         trace_ocfs2_encode_fh_type(type);
 263         return type;
 264 }
 265
 266 static struct dentry *ocfs2_fh_to_dentry(struct super_block *sb,
 267                 struct fid *fid, int fh_len, int fh_type)
 268 {
 269         struct ocfs2_inode_handle handle;
 270
 271         if (fh_len < 3 || fh_type > 2)
 272                 return NULL;
 273
 274         handle.ih_blkno = (u64)le32_to_cpu(fid->raw[0]) << 32;
 275         handle.ih_blkno |= (u64)le32_to_cpu(fid->raw[1]);
 276         handle.ih_generation = le32_to_cpu(fid->raw[2]);
 277         return ocfs2_get_dentry(sb, &handle);
 278 }
 279
 280 static struct dentry *ocfs2_fh_to_parent(struct super_block *sb,
 281                 struct fid *fid, int fh_len, int fh_type)
 282 {
 283         struct ocfs2_inode_handle parent;
 284
 285         if (fh_type != 2 || fh_len < 6)
 286                 return NULL;
 287
 288         parent.ih_blkno = (u64)le32_to_cpu(fid->raw[3]) << 32;
 289         parent.ih_blkno |= (u64)le32_to_cpu(fid->raw[4]);
 290         parent.ih_generation = le32_to_cpu(fid->raw[5]);
 291         return ocfs2_get_dentry(sb, &parent);
 292 }
 293
 294 const struct export_operations ocfs2_export_ops = {
 295         .encode_fh      = ocfs2_encode_fh,
 296         .fh_to_dentry   = ocfs2_fh_to_dentry,
 297         .fh_to_parent   = ocfs2_fh_to_parent,
 298         .get_parent     = ocfs2_get_parent,
 299 };