git.oblomov.eu Git - linux-2.6/blob - 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 <asm/semaphore.h>
  16
  17 #include "gfs2.h"
  18 #include "dir.h"
  19 #include "glock.h"
  20 #include "glops.h"
  21 #include "inode.h"
  22 #include "ops_export.h"
  23 #include "rgrp.h"
  24
  25 static struct dentry *gfs2_decode_fh(struct super_block *sb,
  26                                      __u32 *fh,
  27                                      int fh_len,
  28                                      int fh_type,
  29                                      int (*acceptable)(void *context,
  30                                                        struct dentry *dentry),
  31                                      void *context)
  32 {
  33         struct gfs2_inum this, parent;
  34
  35         if (fh_type != fh_len)
  36                 return NULL;
  37
  38         memset(&parent, 0, sizeof(struct gfs2_inum));
  39
  40         switch (fh_type) {
  41         case 8:
  42                 parent.no_formal_ino = ((uint64_t)be32_to_cpu(fh[4])) << 32;
  43                 parent.no_formal_ino |= be32_to_cpu(fh[5]);
  44                 parent.no_addr = ((uint64_t)be32_to_cpu(fh[6])) << 32;
  45                 parent.no_addr |= be32_to_cpu(fh[7]);
  46         case 4:
  47                 this.no_formal_ino = ((uint64_t)be32_to_cpu(fh[0])) << 32;
  48                 this.no_formal_ino |= be32_to_cpu(fh[1]);
  49                 this.no_addr = ((uint64_t)be32_to_cpu(fh[2])) << 32;
  50                 this.no_addr |= be32_to_cpu(fh[3]);
  51                 break;
  52         default:
  53                 return NULL;
  54         }
  55
  56         return gfs2_export_ops.find_exported_dentry(sb, &this, &parent,
  57                                                     acceptable, context);
  58 }
  59
  60 static int gfs2_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
  61                           int connectable)
  62 {
  63         struct inode *inode = dentry->d_inode;
  64         struct gfs2_inode *ip = get_v2ip(inode);
  65         struct gfs2_sbd *sdp = ip->i_sbd;
  66
  67         if (*len < 4 || (connectable && *len < 8))
  68                 return 255;
  69
  70         fh[0] = ip->i_num.no_formal_ino >> 32;
  71         fh[0] = cpu_to_be32(fh[0]);
  72         fh[1] = ip->i_num.no_formal_ino & 0xFFFFFFFF;
  73         fh[1] = cpu_to_be32(fh[1]);
  74         fh[2] = ip->i_num.no_addr >> 32;
  75         fh[2] = cpu_to_be32(fh[2]);
  76         fh[3] = ip->i_num.no_addr & 0xFFFFFFFF;
  77         fh[3] = cpu_to_be32(fh[3]);
  78         *len = 4;
  79
  80         if (!connectable || ip == get_v2ip(sdp->sd_root_dir))
  81                 return *len;
  82
  83         spin_lock(&dentry->d_lock);
  84         inode = dentry->d_parent->d_inode;
  85         ip = get_v2ip(inode);
  86         gfs2_inode_hold(ip);
  87         spin_unlock(&dentry->d_lock);
  88
  89         fh[4] = ip->i_num.no_formal_ino >> 32;
  90         fh[4] = cpu_to_be32(fh[4]);
  91         fh[5] = ip->i_num.no_formal_ino & 0xFFFFFFFF;
  92         fh[5] = cpu_to_be32(fh[5]);
  93         fh[6] = ip->i_num.no_addr >> 32;
  94         fh[6] = cpu_to_be32(fh[6]);
  95         fh[7] = ip->i_num.no_addr & 0xFFFFFFFF;
  96         fh[7] = cpu_to_be32(fh[7]);
  97         *len = 8;
  98
  99         gfs2_inode_put(ip);
 100
 101         return *len;
 102 }
 103
 104 struct get_name_filldir {
 105         struct gfs2_inum inum;
 106         char *name;
 107 };
 108
 109 static int get_name_filldir(void *opaque, const char *name, unsigned int length,
 110                             uint64_t offset, struct gfs2_inum *inum,
 111                             unsigned int type)
 112 {
 113         struct get_name_filldir *gnfd = (struct get_name_filldir *)opaque;
 114
 115         if (!gfs2_inum_equal(inum, &gnfd->inum))
 116                 return 0;
 117
 118         memcpy(gnfd->name, name, length);
 119         gnfd->name[length] = 0;
 120
 121         return 1;
 122 }
 123
 124 static int gfs2_get_name(struct dentry *parent, char *name,
 125                          struct dentry *child)
 126 {
 127         struct inode *dir = parent->d_inode;
 128         struct inode *inode = child->d_inode;
 129         struct gfs2_inode *dip, *ip;
 130         struct get_name_filldir gnfd;
 131         struct gfs2_holder gh;
 132         uint64_t offset = 0;
 133         int error;
 134
 135         if (!dir)
 136                 return -EINVAL;
 137
 138         if (!S_ISDIR(dir->i_mode) || !inode)
 139                 return -EINVAL;
 140
 141         dip = get_v2ip(dir);
 142         ip = get_v2ip(inode);
 143
 144         *name = 0;
 145         gnfd.inum = ip->i_num;
 146         gnfd.name = name;
 147
 148         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
 149         if (error)
 150                 return error;
 151
 152         error = gfs2_dir_read(dip, &offset, &gnfd, get_name_filldir);
 153
 154         gfs2_glock_dq_uninit(&gh);
 155
 156         if (!error && !*name)
 157                 error = -ENOENT;
 158
 159         return error;
 160 }
 161
 162 static struct dentry *gfs2_get_parent(struct dentry *child)
 163 {
 164         struct gfs2_inode *dip = get_v2ip(child->d_inode);
 165         struct qstr dotdot = { .name = "..", .len = 2 };
 166         struct inode *inode;
 167         struct dentry *dentry;
 168         int error;
 169
 170         error = gfs2_lookupi(child->d_inode, &dotdot, 1, &inode);
 171         if (error)
 172                 return ERR_PTR(error);
 173
 174         dentry = d_alloc_anon(inode);
 175         if (!dentry) {
 176                 iput(inode);
 177                 return ERR_PTR(-ENOMEM);
 178         }
 179
 180         return dentry;
 181 }
 182
 183 static struct dentry *gfs2_get_dentry(struct super_block *sb, void *inum_p)
 184 {
 185         struct gfs2_sbd *sdp = get_v2sdp(sb);
 186         struct gfs2_inum *inum = (struct gfs2_inum *)inum_p;
 187         struct gfs2_holder i_gh, ri_gh, rgd_gh;
 188         struct gfs2_rgrpd *rgd;
 189         struct gfs2_inode *ip;
 190         struct inode *inode;
 191         struct dentry *dentry;
 192         int error;
 193
 194         /* System files? */
 195
 196         inode = gfs2_iget(sb, inum);
 197         if (inode) {
 198                 ip = get_v2ip(inode);
 199                 if (ip->i_num.no_formal_ino != inum->no_formal_ino) {
 200                         iput(inode);
 201                         return ERR_PTR(-ESTALE);
 202                 }
 203                 goto out_inode;
 204         }
 205
 206         error = gfs2_glock_nq_num(sdp,
 207                                   inum->no_addr, &gfs2_inode_glops,
 208                                   LM_ST_SHARED, LM_FLAG_ANY | GL_LOCAL_EXCL,
 209                                   &i_gh);
 210         if (error)
 211                 return ERR_PTR(error);
 212
 213         error = gfs2_inode_get(i_gh.gh_gl, inum, NO_CREATE, &ip);
 214         if (error)
 215                 goto fail;
 216         if (ip)
 217                 goto out_ip;
 218
 219         error = gfs2_rindex_hold(sdp, &ri_gh);
 220         if (error)
 221                 goto fail;
 222
 223         error = -EINVAL;
 224         rgd = gfs2_blk2rgrpd(sdp, inum->no_addr);
 225         if (!rgd)
 226                 goto fail_rindex;
 227
 228         error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
 229         if (error)
 230                 goto fail_rindex;
 231
 232         error = -ESTALE;
 233         if (gfs2_get_block_type(rgd, inum->no_addr) != GFS2_BLKST_DINODE)
 234                 goto fail_rgd;
 235
 236         gfs2_glock_dq_uninit(&rgd_gh);
 237         gfs2_glock_dq_uninit(&ri_gh);
 238
 239         error = gfs2_inode_get(i_gh.gh_gl, inum, CREATE, &ip);
 240         if (error)
 241                 goto fail;
 242
 243         error = gfs2_inode_refresh(ip);
 244         if (error) {
 245                 gfs2_inode_put(ip);
 246                 goto fail;
 247         }
 248
 249  out_ip:
 250         error = -EIO;
 251         if (ip->i_di.di_flags & GFS2_DIF_SYSTEM) {
 252                 gfs2_inode_put(ip);
 253                 goto fail;
 254         }
 255
 256         gfs2_glock_dq_uninit(&i_gh);
 257
 258         inode = gfs2_ip2v(ip);
 259         gfs2_inode_put(ip);
 260
 261         if (!inode)
 262                 return ERR_PTR(-ENOMEM);
 263
 264  out_inode:
 265         dentry = d_alloc_anon(inode);
 266         if (!dentry) {
 267                 iput(inode);
 268                 return ERR_PTR(-ENOMEM);
 269         }
 270
 271         return dentry;
 272
 273  fail_rgd:
 274         gfs2_glock_dq_uninit(&rgd_gh);
 275
 276  fail_rindex:
 277         gfs2_glock_dq_uninit(&ri_gh);
 278
 279  fail:
 280         gfs2_glock_dq_uninit(&i_gh);
 281         return ERR_PTR(error);
 282 }
 283
 284 struct export_operations gfs2_export_ops = {
 285         .decode_fh = gfs2_decode_fh,
 286         .encode_fh = gfs2_encode_fh,
 287         .get_name = gfs2_get_name,
 288         .get_parent = gfs2_get_parent,
 289         .get_dentry = gfs2_get_dentry,
 290 };
 291