fs/ocfs2/export.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * export.c
   4  *
   5  * Functions to facilitate NFS exporting
   6  *
   7  * Copyright (C) 2002, 2005 Oracle.  All rights reserved.
   8  */
   9
  10 #include <linux/fs.h>
  11 #include <linux/types.h>
  12
  13 #include <cluster/masklog.h>
  14
  15 #include "ocfs2.h"
  16
  17 #include "alloc.h"
  18 #include "dir.h"
  19 #include "dlmglue.h"
  20 #include "dcache.h"
  21 #include "export.h"
  22 #include "inode.h"
  23
  24 #include "buffer_head_io.h"
  25 #include "suballoc.h"
  26 #include "ocfs2_trace.h"
  27
  28 struct ocfs2_inode_handle
  29 {
  30         u64 ih_blkno;
  31         u32 ih_generation;
  32 };
  33
  34 static struct dentry *ocfs2_get_dentry(struct super_block *sb,
  35                 struct ocfs2_inode_handle *handle)
  36 {
  37         struct inode *inode;
  38         struct ocfs2_super *osb = OCFS2_SB(sb);
  39         u64 blkno = handle->ih_blkno;
  40         int status, set;
  41         struct dentry *result;
  42
  43         trace_ocfs2_get_dentry_begin(sb, handle, (unsigned long long)blkno);
  44
  45         if (blkno == 0) {
  46                 result = ERR_PTR(-ESTALE);
  47                 goto bail;
  48         }
  49
  50         inode = ocfs2_ilookup(sb, blkno);
  51         /*
  52          * If the inode exists in memory, we only need to check it's
  53          * generation number
  54          */
  55         if (inode)
  56                 goto check_gen;
  57
  58         /*
  59          * This will synchronize us against ocfs2_delete_inode() on
  60          * all nodes
  61          */
  62         status = ocfs2_nfs_sync_lock(osb, 1);
  63         if (status < 0) {
  64                 mlog(ML_ERROR, "getting nfs sync lock(EX) failed %d\n", status);
  65                 goto check_err;
  66         }
  67
  68         status = ocfs2_test_inode_bit(osb, blkno, &set);
  69         if (status < 0) {
  70                 if (status == -EINVAL) {
  71                         /*
  72                          * The blkno NFS gave us doesn't even show up
  73                          * as an inode, we return -ESTALE to be
  74                          * nice
  75                          */
  76                         status = -ESTALE;
  77                 } else
  78                         mlog(ML_ERROR, "test inode bit failed %d\n", status);
  79                 goto unlock_nfs_sync;
  80         }
  81
  82         trace_ocfs2_get_dentry_test_bit(status, set);
  83         /* If the inode allocator bit is clear, this inode must be stale */
  84         if (!set) {
  85                 status = -ESTALE;
  86                 goto unlock_nfs_sync;
  87         }
  88
  89         inode = ocfs2_iget(osb, blkno, 0, 0);
  90
  91 unlock_nfs_sync:
  92         ocfs2_nfs_sync_unlock(osb, 1);
  93
  94 check_err:
  95         if (status < 0) {
  96                 if (status == -ESTALE) {
  97                         trace_ocfs2_get_dentry_stale((unsigned long long)blkno,
  98                                                      handle->ih_generation);
  99                 }
 100                 result = ERR_PTR(status);
 101                 goto bail;
 102         }
 103
 104         if (IS_ERR(inode)) {
 105                 mlog_errno(PTR_ERR(inode));
 106                 result = ERR_CAST(inode);
 107                 goto bail;
 108         }
 109
 110 check_gen:
 111         if (handle->ih_generation != inode->i_generation) {
 112                 trace_ocfs2_get_dentry_generation((unsigned long long)blkno,
 113                                                   handle->ih_generation,
 114                                                   inode->i_generation);
 115                 iput(inode);
 116                 result = ERR_PTR(-ESTALE);
 117                 goto bail;
 118         }
 119
 120         result = d_obtain_alias(inode);
 121         if (IS_ERR(result))
 122                 mlog_errno(PTR_ERR(result));
 123
 124 bail:
 125         trace_ocfs2_get_dentry_end(result);
 126         return result;
 127 }
 128
 129 static struct dentry *ocfs2_get_parent(struct dentry *child)
 130 {
 131         int status;
 132         u64 blkno;
 133         struct dentry *parent;
 134         struct inode *dir = d_inode(child);
 135         int set;
 136
 137         trace_ocfs2_get_parent(child, child->d_name.len, child->d_name.name,
 138                                (unsigned long long)OCFS2_I(dir)->ip_blkno);
 139
 140         status = ocfs2_nfs_sync_lock(OCFS2_SB(dir->i_sb), 1);
 141         if (status < 0) {
 142                 mlog(ML_ERROR, "getting nfs sync lock(EX) failed %d\n", status);
 143                 parent = ERR_PTR(status);
 144                 goto bail;
 145         }
 146
 147         status = ocfs2_inode_lock(dir, NULL, 0);
 148         if (status < 0) {
 149                 if (status != -ENOENT)
 150                         mlog_errno(status);
 151                 parent = ERR_PTR(status);
 152                 goto unlock_nfs_sync;
 153         }
 154
 155         status = ocfs2_lookup_ino_from_name(dir, "..", 2, &blkno);
 156         if (status < 0) {
 157                 parent = ERR_PTR(-ENOENT);
 158                 goto bail_unlock;
 159         }
 160
 161         status = ocfs2_test_inode_bit(OCFS2_SB(dir->i_sb), blkno, &set);
 162         if (status < 0) {
 163                 if (status == -EINVAL) {
 164                         status = -ESTALE;
 165                 } else
 166                         mlog(ML_ERROR, "test inode bit failed %d\n", status);
 167                 parent = ERR_PTR(status);
 168                 goto bail_unlock;
 169         }
 170
 171         trace_ocfs2_get_dentry_test_bit(status, set);
 172         if (!set) {
 173                 status = -ESTALE;
 174                 parent = ERR_PTR(status);
 175                 goto bail_unlock;
 176         }
 177
 178         parent = d_obtain_alias(ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0, 0));
 179
 180 bail_unlock:
 181         ocfs2_inode_unlock(dir, 0);
 182
 183 unlock_nfs_sync:
 184         ocfs2_nfs_sync_unlock(OCFS2_SB(dir->i_sb), 1);
 185
 186 bail:
 187         trace_ocfs2_get_parent_end(parent);
 188
 189         return parent;
 190 }
 191
 192 static int ocfs2_encode_fh(struct inode *inode, u32 *fh_in, int *max_len,
 193                            struct inode *parent)
 194 {
 195         int len = *max_len;
 196         int type = 1;
 197         u64 blkno;
 198         u32 generation;
 199         __le32 *fh = (__force __le32 *) fh_in;
 200
 201 #ifdef TRACE_HOOKS_ARE_NOT_BRAINDEAD_IN_YOUR_OPINION
 202 #error "You go ahead and fix that mess, then.  Somehow"
 203         trace_ocfs2_encode_fh_begin(dentry, dentry->d_name.len,
 204                                     dentry->d_name.name,
 205                                     fh, len, connectable);
 206 #endif
 207
 208         if (parent && (len < 6)) {
 209                 *max_len = 6;
 210                 type = FILEID_INVALID;
 211                 goto bail;
 212         } else if (len < 3) {
 213                 *max_len = 3;
 214                 type = FILEID_INVALID;
 215                 goto bail;
 216         }
 217
 218         blkno = OCFS2_I(inode)->ip_blkno;
 219         generation = inode->i_generation;
 220
 221         trace_ocfs2_encode_fh_self((unsigned long long)blkno, generation);
 222
 223         len = 3;
 224         fh[0] = cpu_to_le32((u32)(blkno >> 32));
 225         fh[1] = cpu_to_le32((u32)(blkno & 0xffffffff));
 226         fh[2] = cpu_to_le32(generation);
 227
 228         if (parent) {
 229                 blkno = OCFS2_I(parent)->ip_blkno;
 230                 generation = parent->i_generation;
 231
 232                 fh[3] = cpu_to_le32((u32)(blkno >> 32));
 233                 fh[4] = cpu_to_le32((u32)(blkno & 0xffffffff));
 234                 fh[5] = cpu_to_le32(generation);
 235
 236                 len = 6;
 237                 type = 2;
 238
 239                 trace_ocfs2_encode_fh_parent((unsigned long long)blkno,
 240                                              generation);
 241         }
 242
 243         *max_len = len;
 244
 245 bail:
 246         trace_ocfs2_encode_fh_type(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 };