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 version 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_fh_obj fh_obj;
  38         struct gfs2_inum *this, parent;
  39
  40         if (fh_type != fh_len)
  41                 return NULL;
  42
  43         this            = &fh_obj.this;
  44         fh_obj.imode    = DT_UNKNOWN;
  45         memset(&parent, 0, sizeof(struct gfs2_inum));
  46
  47         switch (fh_type) {
  48         case 10:
  49                 parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
  50                 parent.no_formal_ino |= be32_to_cpu(fh[5]);
  51                 parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
  52                 parent.no_addr |= be32_to_cpu(fh[7]);
  53                 fh_obj.imode = be32_to_cpu(fh[8]);
  54         case 4:
  55                 this->no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
  56                 this->no_formal_ino |= be32_to_cpu(fh[1]);
  57                 this->no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
  58                 this->no_addr |= be32_to_cpu(fh[3]);
  59                 break;
  60         default:
  61                 return NULL;
  62         }
  63
  64         return gfs2_export_ops.find_exported_dentry(sb, &fh_obj, &parent,
  65                                                     acceptable, context);
  66 }
  67
  68 static int gfs2_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
  69                           int connectable)
  70 {
  71         struct inode *inode = dentry->d_inode;
  72         struct super_block *sb = inode->i_sb;
  73         struct gfs2_inode *ip = GFS2_I(inode);
  74
  75         if (*len < 4 || (connectable && *len < 10))
  76                 return 255;
  77
  78         fh[0] = ip->i_num.no_formal_ino >> 32;
  79         fh[0] = cpu_to_be32(fh[0]);
  80         fh[1] = ip->i_num.no_formal_ino & 0xFFFFFFFF;
  81         fh[1] = cpu_to_be32(fh[1]);
  82         fh[2] = ip->i_num.no_addr >> 32;
  83         fh[2] = cpu_to_be32(fh[2]);
  84         fh[3] = ip->i_num.no_addr & 0xFFFFFFFF;
  85         fh[3] = cpu_to_be32(fh[3]);
  86         *len = 4;
  87
  88         if (!connectable || inode == sb->s_root->d_inode)
  89                 return *len;
  90
  91         spin_lock(&dentry->d_lock);
  92         inode = dentry->d_parent->d_inode;
  93         ip = GFS2_I(inode);
  94         igrab(inode);
  95         spin_unlock(&dentry->d_lock);
  96
  97         fh[4] = ip->i_num.no_formal_ino >> 32;
  98         fh[4] = cpu_to_be32(fh[4]);
  99         fh[5] = ip->i_num.no_formal_ino & 0xFFFFFFFF;
 100         fh[5] = cpu_to_be32(fh[5]);
 101         fh[6] = ip->i_num.no_addr >> 32;
 102         fh[6] = cpu_to_be32(fh[6]);
 103         fh[7] = ip->i_num.no_addr & 0xFFFFFFFF;
 104         fh[7] = cpu_to_be32(fh[7]);
 105
 106         fh[8]  = cpu_to_be32(inode->i_mode);
 107         fh[9]  = 0;     /* pad to double word */
 108         *len = 10;
 109
 110         iput(inode);
 111
 112         return *len;
 113 }
 114
 115 struct get_name_filldir {
 116         struct gfs2_inum inum;
 117         char *name;
 118 };
 119
 120 static int get_name_filldir(void *opaque, const char *name, unsigned int length,
 121                             u64 offset, struct gfs2_inum *inum,
 122                             unsigned int type)
 123 {
 124         struct get_name_filldir *gnfd = (struct get_name_filldir *)opaque;
 125
 126         if (!gfs2_inum_equal(inum, &gnfd->inum))
 127                 return 0;
 128
 129         memcpy(gnfd->name, name, length);
 130         gnfd->name[length] = 0;
 131
 132         return 1;
 133 }
 134
 135 static int gfs2_get_name(struct dentry *parent, char *name,
 136                          struct dentry *child)
 137 {
 138         struct inode *dir = parent->d_inode;
 139         struct inode *inode = child->d_inode;
 140         struct gfs2_inode *dip, *ip;
 141         struct get_name_filldir gnfd;
 142         struct gfs2_holder gh;
 143         u64 offset = 0;
 144         int error;
 145
 146         if (!dir)
 147                 return -EINVAL;
 148
 149         if (!S_ISDIR(dir->i_mode) || !inode)
 150                 return -EINVAL;
 151
 152         dip = GFS2_I(dir);
 153         ip = GFS2_I(inode);
 154
 155         *name = 0;
 156         gnfd.inum = ip->i_num;
 157         gnfd.name = name;
 158
 159         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
 160         if (error)
 161                 return error;
 162
 163         error = gfs2_dir_read(dir, &offset, &gnfd, get_name_filldir);
 164
 165         gfs2_glock_dq_uninit(&gh);
 166
 167         if (!error && !*name)
 168                 error = -ENOENT;
 169
 170         return error;
 171 }
 172
 173 static struct dentry *gfs2_get_parent(struct dentry *child)
 174 {
 175         struct qstr dotdot;
 176         struct inode *inode;
 177         struct dentry *dentry;
 178
 179         gfs2_str2qstr(&dotdot, "..");
 180         inode = gfs2_lookupi(child->d_inode, &dotdot, 1, NULL);
 181
 182         if (!inode)
 183                 return ERR_PTR(-ENOENT);
 184         if (IS_ERR(inode))
 185                 return ERR_PTR(PTR_ERR(inode));
 186
 187         dentry = d_alloc_anon(inode);
 188         if (!dentry) {
 189                 iput(inode);
 190                 return ERR_PTR(-ENOMEM);
 191         }
 192
 193         return dentry;
 194 }
 195
 196 static struct dentry *gfs2_get_dentry(struct super_block *sb, void *inum_obj)
 197 {
 198         struct gfs2_sbd *sdp = sb->s_fs_info;
 199         struct gfs2_fh_obj *fh_obj = (struct gfs2_fh_obj *)inum_obj;
 200         struct gfs2_inum *inum = &fh_obj->this;
 201         struct gfs2_holder i_gh, ri_gh, rgd_gh;
 202         struct gfs2_rgrpd *rgd;
 203         struct inode *inode;
 204         struct dentry *dentry;
 205         int error;
 206
 207         /* System files? */
 208
 209         inode = gfs2_ilookup(sb, inum);
 210         if (inode) {
 211                 if (GFS2_I(inode)->i_num.no_formal_ino != inum->no_formal_ino) {
 212                         iput(inode);
 213                         return ERR_PTR(-ESTALE);
 214                 }
 215                 goto out_inode;
 216         }
 217
 218         error = gfs2_glock_nq_num(sdp, inum->no_addr, &gfs2_inode_glops,
 219                                   LM_ST_SHARED, LM_FLAG_ANY | GL_LOCAL_EXCL,
 220                                   &i_gh);
 221         if (error)
 222                 return ERR_PTR(error);
 223
 224         error = gfs2_rindex_hold(sdp, &ri_gh);
 225         if (error)
 226                 goto fail;
 227
 228         error = -EINVAL;
 229         rgd = gfs2_blk2rgrpd(sdp, inum->no_addr);
 230         if (!rgd)
 231                 goto fail_rindex;
 232
 233         error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
 234         if (error)
 235                 goto fail_rindex;
 236
 237         error = -ESTALE;
 238         if (gfs2_get_block_type(rgd, inum->no_addr) != GFS2_BLKST_DINODE)
 239                 goto fail_rgd;
 240
 241         gfs2_glock_dq_uninit(&rgd_gh);
 242         gfs2_glock_dq_uninit(&ri_gh);
 243
 244         inode = gfs2_inode_lookup(sb, inum, fh_obj->imode);
 245         if (!inode)
 246                 goto fail;
 247         if (IS_ERR(inode)) {
 248                 error = PTR_ERR(inode);
 249                 goto fail;
 250         }
 251
 252         error = gfs2_inode_refresh(GFS2_I(inode));
 253         if (error) {
 254                 iput(inode);
 255                 goto fail;
 256         }
 257
 258         error = -EIO;
 259         if (GFS2_I(inode)->i_di.di_flags & GFS2_DIF_SYSTEM) {
 260                 iput(inode);
 261                 goto fail;
 262         }
 263
 264         gfs2_glock_dq_uninit(&i_gh);
 265
 266 out_inode:
 267         dentry = d_alloc_anon(inode);
 268         if (!dentry) {
 269                 iput(inode);
 270                 return ERR_PTR(-ENOMEM);
 271         }
 272
 273         return dentry;
 274
 275 fail_rgd:
 276         gfs2_glock_dq_uninit(&rgd_gh);
 277
 278 fail_rindex:
 279         gfs2_glock_dq_uninit(&ri_gh);
 280
 281 fail:
 282         gfs2_glock_dq_uninit(&i_gh);
 283         return ERR_PTR(error);
 284 }
 285
 286 struct export_operations gfs2_export_ops = {
 287         .decode_fh = gfs2_decode_fh,
 288         .encode_fh = gfs2_encode_fh,
 289         .get_name = gfs2_get_name,
 290         .get_parent = gfs2_get_parent,
 291         .get_dentry = gfs2_get_dentry,
 292 };
 293