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                 result->d_op = &ocfs2_dentry_ops;
 142         else
 143                 mlog_errno(PTR_ERR(result));
 144
 145 bail:
 146         mlog_exit_ptr(result);
 147         return result;
 148 }
 149
 150 static struct dentry *ocfs2_get_parent(struct dentry *child)
 151 {
 152         int status;
 153         u64 blkno;
 154         struct dentry *parent;
 155         struct inode *dir = child->d_inode;
 156
 157         mlog_entry("(0x%p, '%.*s')\n", child,
 158                    child->d_name.len, child->d_name.name);
 159
 160         mlog(0, "find parent of directory %llu\n",
 161              (unsigned long long)OCFS2_I(dir)->ip_blkno);
 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 bail;
 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         parent = d_obtain_alias(ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0, 0));
 178         if (!IS_ERR(parent))
 179                 parent->d_op = &ocfs2_dentry_ops;
 180
 181 bail_unlock:
 182         ocfs2_inode_unlock(dir, 0);
 183
 184 bail:
 185         mlog_exit_ptr(parent);
 186
 187         return parent;
 188 }
 189
 190 static int ocfs2_encode_fh(struct dentry *dentry, u32 *fh_in, int *max_len,
 191                            int connectable)
 192 {
 193         struct inode *inode = dentry->d_inode;
 194         int len = *max_len;
 195         int type = 1;
 196         u64 blkno;
 197         u32 generation;
 198         __le32 *fh = (__force __le32 *) fh_in;
 199
 200         mlog_entry("(0x%p, '%.*s', 0x%p, %d, %d)\n", dentry,
 201                    dentry->d_name.len, dentry->d_name.name,
 202                    fh, len, connectable);
 203
 204         if (len < 3 || (connectable && len < 6)) {
 205                 mlog(ML_ERROR, "fh buffer is too small for encoding\n");
 206                 type = 255;
 207                 goto bail;
 208         }
 209
 210         blkno = OCFS2_I(inode)->ip_blkno;
 211         generation = inode->i_generation;
 212
 213         mlog(0, "Encoding fh: blkno: %llu, generation: %u\n",
 214              (unsigned long long)blkno, generation);
 215
 216         len = 3;
 217         fh[0] = cpu_to_le32((u32)(blkno >> 32));
 218         fh[1] = cpu_to_le32((u32)(blkno & 0xffffffff));
 219         fh[2] = cpu_to_le32(generation);
 220
 221         if (connectable && !S_ISDIR(inode->i_mode)) {
 222                 struct inode *parent;
 223
 224                 spin_lock(&dentry->d_lock);
 225
 226                 parent = dentry->d_parent->d_inode;
 227                 blkno = OCFS2_I(parent)->ip_blkno;
 228                 generation = parent->i_generation;
 229
 230                 fh[3] = cpu_to_le32((u32)(blkno >> 32));
 231                 fh[4] = cpu_to_le32((u32)(blkno & 0xffffffff));
 232                 fh[5] = cpu_to_le32(generation);
 233
 234                 spin_unlock(&dentry->d_lock);
 235
 236                 len = 6;
 237                 type = 2;
 238
 239                 mlog(0, "Encoding parent: blkno: %llu, generation: %u\n",
 240                      (unsigned long long)blkno, generation);
 241         }
 242
 243         *max_len = len;
 244
 245 bail:
 246         mlog_exit(type);
 247         return type;
 248 }
 249
 250 static struct dentry *ocfs2_fh_to_dentry(struct super_block *sb,
 251                 struct fid *fid, int fh_len, int fh_type)
 252 {
 253         struct ocfs2_inode_handle handle;
 254
 255         if (fh_len < 3 || fh_type > 2)
 256                 return NULL;
 257
 258         handle.ih_blkno = (u64)le32_to_cpu(fid->raw[0]) << 32;
 259         handle.ih_blkno |= (u64)le32_to_cpu(fid->raw[1]);
 260         handle.ih_generation = le32_to_cpu(fid->raw[2]);
 261         return ocfs2_get_dentry(sb, &handle);
 262 }
 263
 264 static struct dentry *ocfs2_fh_to_parent(struct super_block *sb,
 265                 struct fid *fid, int fh_len, int fh_type)
 266 {
 267         struct ocfs2_inode_handle parent;
 268
 269         if (fh_type != 2 || fh_len < 6)
 270                 return NULL;
 271
 272         parent.ih_blkno = (u64)le32_to_cpu(fid->raw[3]) << 32;
 273         parent.ih_blkno |= (u64)le32_to_cpu(fid->raw[4]);
 274         parent.ih_generation = le32_to_cpu(fid->raw[5]);
 275         return ocfs2_get_dentry(sb, &parent);
 276 }
 277
 278 const struct export_operations ocfs2_export_ops = {
 279         .encode_fh      = ocfs2_encode_fh,
 280         .fh_to_dentry   = ocfs2_fh_to_dentry,
 281         .fh_to_parent   = ocfs2_fh_to_parent,
 282         .get_parent     = ocfs2_get_parent,
 283 };