fs/gfs2/ops_export.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2005 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 <asm/semaphore.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
  28 static struct dentry *gfs2_decode_fh(struct super_block *sb,
  29                                      __u32 *fh,
  30                                      int fh_len,
  31                                      int fh_type,
  32                                      int (*acceptable)(void *context,
  33                                                        struct dentry *dentry),
  34                                      void *context)
  35 {
  36         struct gfs2_inum this, parent;
  37
  38         if (fh_type != fh_len)
  39                 return NULL;
  40
  41         memset(&parent, 0, sizeof(struct gfs2_inum));
  42
  43         switch (fh_type) {
  44         case 8:
  45                 parent.no_formal_ino = ((uint64_t)be32_to_cpu(fh[4])) << 32;
  46                 parent.no_formal_ino |= be32_to_cpu(fh[5]);
  47                 parent.no_addr = ((uint64_t)be32_to_cpu(fh[6])) << 32;
  48                 parent.no_addr |= be32_to_cpu(fh[7]);
  49         case 4:
  50                 this.no_formal_ino = ((uint64_t)be32_to_cpu(fh[0])) << 32;
  51                 this.no_formal_ino |= be32_to_cpu(fh[1]);
  52                 this.no_addr = ((uint64_t)be32_to_cpu(fh[2])) << 32;
  53                 this.no_addr |= be32_to_cpu(fh[3]);
  54                 break;
  55         default:
  56                 return NULL;
  57         }
  58
  59         return gfs2_export_ops.find_exported_dentry(sb, &this, &parent,
  60                                                     acceptable, context);
  61 }
  62
  63 static int gfs2_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
  64                           int connectable)
  65 {
  66         struct inode *inode = dentry->d_inode;
  67         struct super_block *sb = inode->i_sb;
  68         struct gfs2_inode *ip = inode->u.generic_ip;
  69
  70         if (*len < 4 || (connectable && *len < 8))
  71                 return 255;
  72
  73         fh[0] = ip->i_num.no_formal_ino >> 32;
  74         fh[0] = cpu_to_be32(fh[0]);
  75         fh[1] = ip->i_num.no_formal_ino & 0xFFFFFFFF;
  76         fh[1] = cpu_to_be32(fh[1]);
  77         fh[2] = ip->i_num.no_addr >> 32;
  78         fh[2] = cpu_to_be32(fh[2]);
  79         fh[3] = ip->i_num.no_addr & 0xFFFFFFFF;
  80         fh[3] = cpu_to_be32(fh[3]);
  81         *len = 4;
  82
  83         if (!connectable || inode == sb->s_root->d_inode)
  84                 return *len;
  85
  86         spin_lock(&dentry->d_lock);
  87         inode = dentry->d_parent->d_inode;
  88         ip = inode->u.generic_ip;
  89         gfs2_inode_hold(ip);
  90         spin_unlock(&dentry->d_lock);
  91
  92         fh[4] = ip->i_num.no_formal_ino >> 32;
  93         fh[4] = cpu_to_be32(fh[4]);
  94         fh[5] = ip->i_num.no_formal_ino & 0xFFFFFFFF;
  95         fh[5] = cpu_to_be32(fh[5]);
  96         fh[6] = ip->i_num.no_addr >> 32;
  97         fh[6] = cpu_to_be32(fh[6]);
  98         fh[7] = ip->i_num.no_addr & 0xFFFFFFFF;
  99         fh[7] = cpu_to_be32(fh[7]);
 100         *len = 8;
 101
 102         gfs2_inode_put(ip);
 103
 104         return *len;
 105 }
 106
 107 struct get_name_filldir {
 108         struct gfs2_inum inum;
 109         char *name;
 110 };
 111
 112 static int get_name_filldir(void *opaque, const char *name, unsigned int length,
 113                             uint64_t offset, struct gfs2_inum *inum,
 114                             unsigned int type)
 115 {
 116         struct get_name_filldir *gnfd = (struct get_name_filldir *)opaque;
 117
 118         if (!gfs2_inum_equal(inum, &gnfd->inum))
 119                 return 0;
 120
 121         memcpy(gnfd->name, name, length);
 122         gnfd->name[length] = 0;
 123
 124         return 1;
 125 }
 126
 127 static int gfs2_get_name(struct dentry *parent, char *name,
 128                          struct dentry *child)
 129 {
 130         struct inode *dir = parent->d_inode;
 131         struct inode *inode = child->d_inode;
 132         struct gfs2_inode *dip, *ip;
 133         struct get_name_filldir gnfd;
 134         struct gfs2_holder gh;
 135         uint64_t offset = 0;
 136         int error;
 137
 138         if (!dir)
 139                 return -EINVAL;
 140
 141         if (!S_ISDIR(dir->i_mode) || !inode)
 142                 return -EINVAL;
 143
 144         dip = dir->u.generic_ip;
 145         ip = inode->u.generic_ip;
 146
 147         *name = 0;
 148         gnfd.inum = ip->i_num;
 149         gnfd.name = name;
 150
 151         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
 152         if (error)
 153                 return error;
 154
 155         error = gfs2_dir_read(dip, &offset, &gnfd, get_name_filldir);
 156
 157         gfs2_glock_dq_uninit(&gh);
 158
 159         if (!error && !*name)
 160                 error = -ENOENT;
 161
 162         return error;
 163 }
 164
 165 static struct dentry *gfs2_get_parent(struct dentry *child)
 166 {
 167         struct qstr dotdot = { .name = "..", .len = 2 };
 168         struct inode *inode;
 169         struct dentry *dentry;
 170         int error;
 171
 172         error = gfs2_lookupi(child->d_inode, &dotdot, 1, &inode);
 173         if (error)
 174                 return ERR_PTR(error);
 175
 176         dentry = d_alloc_anon(inode);
 177         if (!dentry) {
 178                 iput(inode);
 179                 return ERR_PTR(-ENOMEM);
 180         }
 181
 182         return dentry;
 183 }
 184
 185 static struct dentry *gfs2_get_dentry(struct super_block *sb, void *inum_p)
 186 {
 187         struct gfs2_sbd *sdp = sb->s_fs_info;
 188         struct gfs2_inum *inum = (struct gfs2_inum *)inum_p;
 189         struct gfs2_holder i_gh, ri_gh, rgd_gh;
 190         struct gfs2_rgrpd *rgd;
 191         struct gfs2_inode *ip;
 192         struct inode *inode;
 193         struct dentry *dentry;
 194         int error;
 195
 196         /* System files? */
 197
 198         inode = gfs2_iget(sb, inum);
 199         if (inode) {
 200                 ip = inode->u.generic_ip;
 201                 if (ip->i_num.no_formal_ino != inum->no_formal_ino) {
 202                         iput(inode);
 203                         return ERR_PTR(-ESTALE);
 204                 }
 205                 goto out_inode;
 206         }
 207
 208         error = gfs2_glock_nq_num(sdp,
 209                                   inum->no_addr, &gfs2_inode_glops,
 210                                   LM_ST_SHARED, LM_FLAG_ANY | GL_LOCAL_EXCL,
 211                                   &i_gh);
 212         if (error)
 213                 return ERR_PTR(error);
 214
 215         error = gfs2_inode_get(i_gh.gh_gl, inum, NO_CREATE, &ip);
 216         if (error)
 217                 goto fail;
 218         if (ip)
 219                 goto out_ip;
 220
 221         error = gfs2_rindex_hold(sdp, &ri_gh);
 222         if (error)
 223                 goto fail;
 224
 225         error = -EINVAL;
 226         rgd = gfs2_blk2rgrpd(sdp, inum->no_addr);
 227         if (!rgd)
 228                 goto fail_rindex;
 229
 230         error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
 231         if (error)
 232                 goto fail_rindex;
 233
 234         error = -ESTALE;
 235         if (gfs2_get_block_type(rgd, inum->no_addr) != GFS2_BLKST_DINODE)
 236                 goto fail_rgd;
 237
 238         gfs2_glock_dq_uninit(&rgd_gh);
 239         gfs2_glock_dq_uninit(&ri_gh);
 240
 241         error = gfs2_inode_get(i_gh.gh_gl, inum, CREATE, &ip);
 242         if (error)
 243                 goto fail;
 244
 245         error = gfs2_inode_refresh(ip);
 246         if (error) {
 247                 gfs2_inode_put(ip);
 248                 goto fail;
 249         }
 250
 251  out_ip:
 252         error = -EIO;
 253         if (ip->i_di.di_flags & GFS2_DIF_SYSTEM) {
 254                 gfs2_inode_put(ip);
 255                 goto fail;
 256         }
 257
 258         gfs2_glock_dq_uninit(&i_gh);
 259
 260         inode = gfs2_ip2v(ip);
 261         gfs2_inode_put(ip);
 262
 263         if (!inode)
 264                 return ERR_PTR(-ENOMEM);
 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