fs/gfs2/ops_export.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
   4  *
   5  * This copyrighted material is made available to anyone wishing to use,
   6  * modify, copy, or redistribute it subject to the terms and conditions
   7  * of the GNU General Public License v.2.
   8  */
   9
  10 #include <linux/sched.h>
  11 #include <linux/slab.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/completion.h>
  14 #include <linux/buffer_head.h>
  15 #include <linux/gfs2_ondisk.h>
  16 #include <linux/crc32.h>
  17
  18 #include "gfs2.h"
  19 #include "lm_interface.h"
  20 #include "incore.h"
  21 #include "dir.h"
  22 #include "glock.h"
  23 #include "glops.h"
  24 #include "inode.h"
  25 #include "ops_export.h"
  26 #include "rgrp.h"
  27 #include "util.h"
  28
  29 static struct dentry *gfs2_decode_fh(struct super_block *sb,
  30                                      __u32 *fh,
  31                                      int fh_len,
  32                                      int fh_type,
  33                                      int (*acceptable)(void *context,
  34                                                        struct dentry *dentry),
  35                                      void *context)
  36 {
  37         struct gfs2_inum this, parent;
  38
  39         if (fh_type != fh_len)
  40                 return NULL;
  41
  42         memset(&parent, 0, sizeof(struct gfs2_inum));
  43
  44         switch (fh_type) {
  45         case 8:
  46                 parent.no_formal_ino = ((uint64_t)be32_to_cpu(fh[4])) << 32;
  47                 parent.no_formal_ino |= be32_to_cpu(fh[5]);
  48                 parent.no_addr = ((uint64_t)be32_to_cpu(fh[6])) << 32;
  49                 parent.no_addr |= be32_to_cpu(fh[7]);
  50         case 4:
  51                 this.no_formal_ino = ((uint64_t)be32_to_cpu(fh[0])) << 32;
  52                 this.no_formal_ino |= be32_to_cpu(fh[1]);
  53                 this.no_addr = ((uint64_t)be32_to_cpu(fh[2])) << 32;
  54                 this.no_addr |= be32_to_cpu(fh[3]);
  55                 break;
  56         default:
  57                 return NULL;
  58         }
  59
  60         return gfs2_export_ops.find_exported_dentry(sb, &this, &parent,
  61                                                     acceptable, context);
  62 }
  63
  64 static int gfs2_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
  65                           int connectable)
  66 {
  67         struct inode *inode = dentry->d_inode;
  68         struct super_block *sb = inode->i_sb;
  69         struct gfs2_inode *ip = GFS2_I(inode);
  70
  71         if (*len < 4 || (connectable && *len < 8))
  72                 return 255;
  73
  74         fh[0] = ip->i_num.no_formal_ino >> 32;
  75         fh[0] = cpu_to_be32(fh[0]);
  76         fh[1] = ip->i_num.no_formal_ino & 0xFFFFFFFF;
  77         fh[1] = cpu_to_be32(fh[1]);
  78         fh[2] = ip->i_num.no_addr >> 32;
  79         fh[2] = cpu_to_be32(fh[2]);
  80         fh[3] = ip->i_num.no_addr & 0xFFFFFFFF;
  81         fh[3] = cpu_to_be32(fh[3]);
  82         *len = 4;
  83
  84         if (!connectable || inode == sb->s_root->d_inode)
  85                 return *len;
  86
  87         spin_lock(&dentry->d_lock);
  88         inode = dentry->d_parent->d_inode;
  89         ip = GFS2_I(inode);
  90         igrab(inode);
  91         spin_unlock(&dentry->d_lock);
  92
  93         fh[4] = ip->i_num.no_formal_ino >> 32;
  94         fh[4] = cpu_to_be32(fh[4]);
  95         fh[5] = ip->i_num.no_formal_ino & 0xFFFFFFFF;
  96         fh[5] = cpu_to_be32(fh[5]);
  97         fh[6] = ip->i_num.no_addr >> 32;
  98         fh[6] = cpu_to_be32(fh[6]);
  99         fh[7] = ip->i_num.no_addr & 0xFFFFFFFF;
 100         fh[7] = cpu_to_be32(fh[7]);
 101         *len = 8;
 102
 103         iput(inode);
 104
 105         return *len;
 106 }
 107
 108 struct get_name_filldir {
 109         struct gfs2_inum inum;
 110         char *name;
 111 };
 112
 113 static int get_name_filldir(void *opaque, const char *name, unsigned int length,
 114                             uint64_t offset, struct gfs2_inum *inum,
 115                             unsigned int type)
 116 {
 117         struct get_name_filldir *gnfd = (struct get_name_filldir *)opaque;
 118
 119         if (!gfs2_inum_equal(inum, &gnfd->inum))
 120                 return 0;
 121
 122         memcpy(gnfd->name, name, length);
 123         gnfd->name[length] = 0;
 124
 125         return 1;
 126 }
 127
 128 static int gfs2_get_name(struct dentry *parent, char *name,
 129                          struct dentry *child)
 130 {
 131         struct inode *dir = parent->d_inode;
 132         struct inode *inode = child->d_inode;
 133         struct gfs2_inode *dip, *ip;
 134         struct get_name_filldir gnfd;
 135         struct gfs2_holder gh;
 136         uint64_t offset = 0;
 137         int error;
 138
 139         if (!dir)
 140                 return -EINVAL;
 141
 142         if (!S_ISDIR(dir->i_mode) || !inode)
 143                 return -EINVAL;
 144
 145         dip = GFS2_I(dir);
 146         ip = GFS2_I(inode);
 147
 148         *name = 0;
 149         gnfd.inum = ip->i_num;
 150         gnfd.name = name;
 151
 152         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
 153         if (error)
 154                 return error;
 155
 156         error = gfs2_dir_read(dir, &offset, &gnfd, get_name_filldir);
 157
 158         gfs2_glock_dq_uninit(&gh);
 159
 160         if (!error && !*name)
 161                 error = -ENOENT;
 162
 163         return error;
 164 }
 165
 166 static struct dentry *gfs2_get_parent(struct dentry *child)
 167 {
 168         struct qstr dotdot;
 169         struct inode *inode;
 170         struct dentry *dentry;
 171
 172         gfs2_str2qstr(&dotdot, "..");
 173         inode = gfs2_lookupi(child->d_inode, &dotdot, 1, NULL);
 174
 175         if (!inode)
 176                 return ERR_PTR(-ENOENT);
 177         if (IS_ERR(inode))
 178                 return ERR_PTR(PTR_ERR(inode));
 179
 180         dentry = d_alloc_anon(inode);
 181         if (!dentry) {
 182                 iput(inode);
 183                 return ERR_PTR(-ENOMEM);
 184         }
 185
 186         return dentry;
 187 }
 188
 189 static struct dentry *gfs2_get_dentry(struct super_block *sb, void *inum_p)
 190 {
 191         struct gfs2_sbd *sdp = sb->s_fs_info;
 192         struct gfs2_inum *inum = inum_p;
 193         struct gfs2_holder i_gh, ri_gh, rgd_gh;
 194         struct gfs2_rgrpd *rgd;
 195         struct inode *inode;
 196         struct dentry *dentry;
 197         int error;
 198
 199         /* System files? */
 200
 201         inode = gfs2_ilookup(sb, inum);
 202         if (inode) {
 203                 if (GFS2_I(inode)->i_num.no_formal_ino != inum->no_formal_ino) {
 204                         iput(inode);
 205                         return ERR_PTR(-ESTALE);
 206                 }
 207                 goto out_inode;
 208         }
 209
 210         error = gfs2_glock_nq_num(sdp, inum->no_addr, &gfs2_inode_glops,
 211                                   LM_ST_SHARED, LM_FLAG_ANY | GL_LOCAL_EXCL,
 212                                   &i_gh);
 213         if (error)
 214                 return ERR_PTR(error);
 215
 216         error = gfs2_rindex_hold(sdp, &ri_gh);
 217         if (error)
 218                 goto fail;
 219
 220         error = -EINVAL;
 221         rgd = gfs2_blk2rgrpd(sdp, inum->no_addr);
 222         if (!rgd)
 223                 goto fail_rindex;
 224
 225         error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
 226         if (error)
 227                 goto fail_rindex;
 228
 229         error = -ESTALE;
 230         if (gfs2_get_block_type(rgd, inum->no_addr) != GFS2_BLKST_DINODE)
 231                 goto fail_rgd;
 232
 233         gfs2_glock_dq_uninit(&rgd_gh);
 234         gfs2_glock_dq_uninit(&ri_gh);
 235
 236         inode = gfs2_inode_lookup(sb, inum, DT_UNKNOWN);
 237         if (!inode)
 238                 goto fail;
 239         if (IS_ERR(inode)) {
 240                 error = PTR_ERR(inode);
 241                 goto fail;
 242         }
 243
 244         error = gfs2_inode_refresh(GFS2_I(inode));
 245         if (error) {
 246                 iput(inode);
 247                 goto fail;
 248         }
 249
 250         error = -EIO;
 251         if (GFS2_I(inode)->i_di.di_flags & GFS2_DIF_SYSTEM) {
 252                 iput(inode);
 253                 goto fail;
 254         }
 255
 256         gfs2_glock_dq_uninit(&i_gh);
 257
 258 out_inode:
 259         dentry = d_alloc_anon(inode);
 260         if (!dentry) {
 261                 iput(inode);
 262                 return ERR_PTR(-ENOMEM);
 263         }
 264
 265         return dentry;
 266
 267 fail_rgd:
 268         gfs2_glock_dq_uninit(&rgd_gh);
 269
 270 fail_rindex:
 271         gfs2_glock_dq_uninit(&ri_gh);
 272
 273 fail:
 274         gfs2_glock_dq_uninit(&i_gh);
 275         return ERR_PTR(error);
 276 }
 277
 278 struct export_operations gfs2_export_ops = {
 279         .decode_fh = gfs2_decode_fh,
 280         .encode_fh = gfs2_encode_fh,
 281         .get_name = gfs2_get_name,
 282         .get_parent = gfs2_get_parent,
 283         .get_dentry = gfs2_get_dentry,
 284 };
 285