linux/fs/ocfs2/export.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/* -*- mode: c; c-basic-offset: 8; -*-
   3 * vim: noexpandtab sw=8 ts=8 sts=0:
   4 *
   5 * export.c
   6 *
   7 * Functions to facilitate NFS exporting
   8 *
   9 * Copyright (C) 2002, 2005 Oracle.  All rights reserved.
  10 */
  11
  12#include <linux/fs.h>
  13#include <linux/types.h>
  14
  15#include <cluster/masklog.h>
  16
  17#include "ocfs2.h"
  18
  19#include "alloc.h"
  20#include "dir.h"
  21#include "dlmglue.h"
  22#include "dcache.h"
  23#include "export.h"
  24#include "inode.h"
  25
  26#include "buffer_head_io.h"
  27#include "suballoc.h"
  28#include "ocfs2_trace.h"
  29
  30struct ocfs2_inode_handle
  31{
  32        u64 ih_blkno;
  33        u32 ih_generation;
  34};
  35
  36static struct dentry *ocfs2_get_dentry(struct super_block *sb,
  37                struct ocfs2_inode_handle *handle)
  38{
  39        struct inode *inode;
  40        struct ocfs2_super *osb = OCFS2_SB(sb);
  41        u64 blkno = handle->ih_blkno;
  42        int status, set;
  43        struct dentry *result;
  44
  45        trace_ocfs2_get_dentry_begin(sb, handle, (unsigned long long)blkno);
  46
  47        if (blkno == 0) {
  48                result = ERR_PTR(-ESTALE);
  49                goto bail;
  50        }
  51
  52        inode = ocfs2_ilookup(sb, blkno);
  53        /*
  54         * If the inode exists in memory, we only need to check it's
  55         * generation number
  56         */
  57        if (inode)
  58                goto check_gen;
  59
  60        /*
  61         * This will synchronize us against ocfs2_delete_inode() on
  62         * all nodes
  63         */
  64        status = ocfs2_nfs_sync_lock(osb, 1);
  65        if (status < 0) {
  66                mlog(ML_ERROR, "getting nfs sync lock(EX) failed %d\n", status);
  67                goto check_err;
  68        }
  69
  70        status = ocfs2_test_inode_bit(osb, blkno, &set);
  71        if (status < 0) {
  72                if (status == -EINVAL) {
  73                        /*
  74                         * The blkno NFS gave us doesn't even show up
  75                         * as an inode, we return -ESTALE to be
  76                         * nice
  77                         */
  78                        status = -ESTALE;
  79                } else
  80                        mlog(ML_ERROR, "test inode bit failed %d\n", status);
  81                goto unlock_nfs_sync;
  82        }
  83
  84        trace_ocfs2_get_dentry_test_bit(status, set);
  85        /* If the inode allocator bit is clear, this inode must be stale */
  86        if (!set) {
  87                status = -ESTALE;
  88                goto unlock_nfs_sync;
  89        }
  90
  91        inode = ocfs2_iget(osb, blkno, 0, 0);
  92
  93unlock_nfs_sync:
  94        ocfs2_nfs_sync_unlock(osb, 1);
  95
  96check_err:
  97        if (status < 0) {
  98                if (status == -ESTALE) {
  99                        trace_ocfs2_get_dentry_stale((unsigned long long)blkno,
 100                                                     handle->ih_generation);
 101                }
 102                result = ERR_PTR(status);
 103                goto bail;
 104        }
 105
 106        if (IS_ERR(inode)) {
 107                mlog_errno(PTR_ERR(inode));
 108                result = ERR_CAST(inode);
 109                goto bail;
 110        }
 111
 112check_gen:
 113        if (handle->ih_generation != inode->i_generation) {
 114                trace_ocfs2_get_dentry_generation((unsigned long long)blkno,
 115                                                  handle->ih_generation,
 116                                                  inode->i_generation);
 117                iput(inode);
 118                result = ERR_PTR(-ESTALE);
 119                goto bail;
 120        }
 121
 122        result = d_obtain_alias(inode);
 123        if (IS_ERR(result))
 124                mlog_errno(PTR_ERR(result));
 125
 126bail:
 127        trace_ocfs2_get_dentry_end(result);
 128        return result;
 129}
 130
 131static struct dentry *ocfs2_get_parent(struct dentry *child)
 132{
 133        int status;
 134        u64 blkno;
 135        struct dentry *parent;
 136        struct inode *dir = d_inode(child);
 137        int set;
 138
 139        trace_ocfs2_get_parent(child, child->d_name.len, child->d_name.name,
 140                               (unsigned long long)OCFS2_I(dir)->ip_blkno);
 141
 142        status = ocfs2_nfs_sync_lock(OCFS2_SB(dir->i_sb), 1);
 143        if (status < 0) {
 144                mlog(ML_ERROR, "getting nfs sync lock(EX) failed %d\n", status);
 145                parent = ERR_PTR(status);
 146                goto bail;
 147        }
 148
 149        status = ocfs2_inode_lock(dir, NULL, 0);
 150        if (status < 0) {
 151                if (status != -ENOENT)
 152                        mlog_errno(status);
 153                parent = ERR_PTR(status);
 154                goto unlock_nfs_sync;
 155        }
 156
 157        status = ocfs2_lookup_ino_from_name(dir, "..", 2, &blkno);
 158        if (status < 0) {
 159                parent = ERR_PTR(-ENOENT);
 160                goto bail_unlock;
 161        }
 162
 163        status = ocfs2_test_inode_bit(OCFS2_SB(dir->i_sb), blkno, &set);
 164        if (status < 0) {
 165                if (status == -EINVAL) {
 166                        status = -ESTALE;
 167                } else
 168                        mlog(ML_ERROR, "test inode bit failed %d\n", status);
 169                parent = ERR_PTR(status);
 170                goto bail_unlock;
 171        }
 172
 173        trace_ocfs2_get_dentry_test_bit(status, set);
 174        if (!set) {
 175                status = -ESTALE;
 176                parent = ERR_PTR(status);
 177                goto bail_unlock;
 178        }
 179
 180        parent = d_obtain_alias(ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0, 0));
 181
 182bail_unlock:
 183        ocfs2_inode_unlock(dir, 0);
 184
 185unlock_nfs_sync:
 186        ocfs2_nfs_sync_unlock(OCFS2_SB(dir->i_sb), 1);
 187
 188bail:
 189        trace_ocfs2_get_parent_end(parent);
 190
 191        return parent;
 192}
 193
 194static int ocfs2_encode_fh(struct inode *inode, u32 *fh_in, int *max_len,
 195                           struct inode *parent)
 196{
 197        int len = *max_len;
 198        int type = 1;
 199        u64 blkno;
 200        u32 generation;
 201        __le32 *fh = (__force __le32 *) fh_in;
 202
 203#ifdef TRACE_HOOKS_ARE_NOT_BRAINDEAD_IN_YOUR_OPINION
 204#error "You go ahead and fix that mess, then.  Somehow"
 205        trace_ocfs2_encode_fh_begin(dentry, dentry->d_name.len,
 206                                    dentry->d_name.name,
 207                                    fh, len, connectable);
 208#endif
 209
 210        if (parent && (len < 6)) {
 211                *max_len = 6;
 212                type = FILEID_INVALID;
 213                goto bail;
 214        } else if (len < 3) {
 215                *max_len = 3;
 216                type = FILEID_INVALID;
 217                goto bail;
 218        }
 219
 220        blkno = OCFS2_I(inode)->ip_blkno;
 221        generation = inode->i_generation;
 222
 223        trace_ocfs2_encode_fh_self((unsigned long long)blkno, generation);
 224
 225        len = 3;
 226        fh[0] = cpu_to_le32((u32)(blkno >> 32));
 227        fh[1] = cpu_to_le32((u32)(blkno & 0xffffffff));
 228        fh[2] = cpu_to_le32(generation);
 229
 230        if (parent) {
 231                blkno = OCFS2_I(parent)->ip_blkno;
 232                generation = parent->i_generation;
 233
 234                fh[3] = cpu_to_le32((u32)(blkno >> 32));
 235                fh[4] = cpu_to_le32((u32)(blkno & 0xffffffff));
 236                fh[5] = cpu_to_le32(generation);
 237
 238                len = 6;
 239                type = 2;
 240
 241                trace_ocfs2_encode_fh_parent((unsigned long long)blkno,
 242                                             generation);
 243        }
 244
 245        *max_len = len;
 246
 247bail:
 248        trace_ocfs2_encode_fh_type(type);
 249        return type;
 250}
 251
 252static struct dentry *ocfs2_fh_to_dentry(struct super_block *sb,
 253                struct fid *fid, int fh_len, int fh_type)
 254{
 255        struct ocfs2_inode_handle handle;
 256
 257        if (fh_len < 3 || fh_type > 2)
 258                return NULL;
 259
 260        handle.ih_blkno = (u64)le32_to_cpu(fid->raw[0]) << 32;
 261        handle.ih_blkno |= (u64)le32_to_cpu(fid->raw[1]);
 262        handle.ih_generation = le32_to_cpu(fid->raw[2]);
 263        return ocfs2_get_dentry(sb, &handle);
 264}
 265
 266static struct dentry *ocfs2_fh_to_parent(struct super_block *sb,
 267                struct fid *fid, int fh_len, int fh_type)
 268{
 269        struct ocfs2_inode_handle parent;
 270
 271        if (fh_type != 2 || fh_len < 6)
 272                return NULL;
 273
 274        parent.ih_blkno = (u64)le32_to_cpu(fid->raw[3]) << 32;
 275        parent.ih_blkno |= (u64)le32_to_cpu(fid->raw[4]);
 276        parent.ih_generation = le32_to_cpu(fid->raw[5]);
 277        return ocfs2_get_dentry(sb, &parent);
 278}
 279
 280const struct export_operations ocfs2_export_ops = {
 281        .encode_fh      = ocfs2_encode_fh,
 282        .fh_to_dentry   = ocfs2_fh_to_dentry,
 283        .fh_to_parent   = ocfs2_fh_to_parent,
 284        .get_parent     = ocfs2_get_parent,
 285};
 286