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         atomic_inc(&get_v2sdp(sb)->sd_ops_export);
  36
  37         if (fh_type != fh_len)
  38                 return NULL;
  39
  40         memset(&parent, 0, sizeof(struct gfs2_inum));
  41
  42         switch (fh_type) {
  43         case 8:
  44                 parent.no_formal_ino = ((uint64_t)be32_to_cpu(fh[4])) << 32;
  45                 parent.no_formal_ino |= be32_to_cpu(fh[5]);
  46                 parent.no_addr = ((uint64_t)be32_to_cpu(fh[6])) << 32;
  47                 parent.no_addr |= be32_to_cpu(fh[7]);
  48         case 4:
  49                 this.no_formal_ino = ((uint64_t)be32_to_cpu(fh[0])) << 32;
  50                 this.no_formal_ino |= be32_to_cpu(fh[1]);
  51                 this.no_addr = ((uint64_t)be32_to_cpu(fh[2])) << 32;
  52                 this.no_addr |= be32_to_cpu(fh[3]);
  53                 break;
  54         default:
  55                 return NULL;
  56         }
  57
  58         return gfs2_export_ops.find_exported_dentry(sb, &this, &parent,
  59                                                     acceptable, context);
  60 }
  61
  62 static int gfs2_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
  63                           int connectable)
  64 {
  65         struct inode *inode = dentry->d_inode;
  66         struct gfs2_inode *ip = get_v2ip(inode);
  67         struct gfs2_sbd *sdp = ip->i_sbd;
  68
  69         atomic_inc(&sdp->sd_ops_export);
  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 || ip == sdp->sd_root_dir)
  85                 return *len;
  86
  87         spin_lock(&dentry->d_lock);
  88         inode = dentry->d_parent->d_inode;
  89         ip = get_v2ip(inode);
  90         gfs2_inode_hold(ip);
  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         gfs2_inode_put(ip);
 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         atomic_inc(&get_v2sdp(dir->i_sb)->sd_ops_export);
 143
 144         if (!S_ISDIR(dir->i_mode) || !inode)
 145                 return -EINVAL;
 146
 147         dip = get_v2ip(dir);
 148         ip = get_v2ip(inode);
 149
 150         *name = 0;
 151         gnfd.inum = ip->i_num;
 152         gnfd.name = name;
 153
 154         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
 155         if (error)
 156                 return error;
 157
 158         error = gfs2_dir_read(dip, &offset, &gnfd, get_name_filldir);
 159
 160         gfs2_glock_dq_uninit(&gh);
 161
 162         if (!error && !*name)
 163                 error = -ENOENT;
 164
 165         return error;
 166 }
 167
 168 static struct dentry *gfs2_get_parent(struct dentry *child)
 169 {
 170         struct gfs2_inode *dip = get_v2ip(child->d_inode);
 171         struct qstr dotdot = { .name = "..", .len = 2 };
 172         struct gfs2_inode *ip;
 173         struct inode *inode;
 174         struct dentry *dentry;
 175         int error;
 176
 177         atomic_inc(&dip->i_sbd->sd_ops_export);
 178
 179         error = gfs2_lookupi(dip, &dotdot, 1, &ip);
 180         if (error)
 181                 return ERR_PTR(error);
 182
 183         inode = gfs2_ip2v(ip);
 184         gfs2_inode_put(ip);
 185
 186         if (!inode)
 187                 return ERR_PTR(-ENOMEM);
 188
 189         dentry = d_alloc_anon(inode);
 190         if (!dentry) {
 191                 iput(inode);
 192                 return ERR_PTR(-ENOMEM);
 193         }
 194
 195         return dentry;
 196 }
 197
 198 static struct dentry *gfs2_get_dentry(struct super_block *sb, void *inum_p)
 199 {
 200         struct gfs2_sbd *sdp = get_v2sdp(sb);
 201         struct gfs2_inum *inum = (struct gfs2_inum *)inum_p;
 202         struct gfs2_holder i_gh, ri_gh, rgd_gh;
 203         struct gfs2_rgrpd *rgd;
 204         struct gfs2_inode *ip;
 205         struct inode *inode;
 206         struct dentry *dentry;
 207         int error;
 208
 209         atomic_inc(&sdp->sd_ops_export);
 210
 211         /* System files? */
 212
 213         inode = gfs2_iget(sb, inum);
 214         if (inode) {
 215                 ip = get_v2ip(inode);
 216                 if (ip->i_num.no_formal_ino != inum->no_formal_ino) {
 217                         iput(inode);
 218                         return ERR_PTR(-ESTALE);
 219                 }
 220                 goto out_inode;
 221         }
 222
 223         error = gfs2_glock_nq_num(sdp,
 224                                   inum->no_addr, &gfs2_inode_glops,
 225                                   LM_ST_SHARED, LM_FLAG_ANY | GL_LOCAL_EXCL,
 226                                   &i_gh);
 227         if (error)
 228                 return ERR_PTR(error);
 229
 230         error = gfs2_inode_get(i_gh.gh_gl, inum, NO_CREATE, &ip);
 231         if (error)
 232                 goto fail;
 233         if (ip)
 234                 goto out_ip;
 235
 236         error = gfs2_rindex_hold(sdp, &ri_gh);
 237         if (error)
 238                 goto fail;
 239
 240         error = -EINVAL;
 241         rgd = gfs2_blk2rgrpd(sdp, inum->no_addr);
 242         if (!rgd)
 243                 goto fail_rindex;
 244
 245         error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
 246         if (error)
 247                 goto fail_rindex;
 248
 249         error = -ESTALE;
 250         if (gfs2_get_block_type(rgd, inum->no_addr) != GFS2_BLKST_DINODE)
 251                 goto fail_rgd;
 252
 253         gfs2_glock_dq_uninit(&rgd_gh);
 254         gfs2_glock_dq_uninit(&ri_gh);
 255
 256         error = gfs2_inode_get(i_gh.gh_gl, inum, CREATE, &ip);
 257         if (error)
 258                 goto fail;
 259
 260         error = gfs2_inode_refresh(ip);
 261         if (error) {
 262                 gfs2_inode_put(ip);
 263                 goto fail;
 264         }
 265
 266         atomic_inc(&sdp->sd_fh2dentry_misses);
 267
 268  out_ip:
 269         error = -EIO;
 270         if (ip->i_di.di_flags & GFS2_DIF_SYSTEM) {
 271                 gfs2_inode_put(ip);
 272                 goto fail;
 273         }
 274
 275         gfs2_glock_dq_uninit(&i_gh);
 276
 277         inode = gfs2_ip2v(ip);
 278         gfs2_inode_put(ip);
 279
 280         if (!inode)
 281                 return ERR_PTR(-ENOMEM);
 282
 283  out_inode:
 284         dentry = d_alloc_anon(inode);
 285         if (!dentry) {
 286                 iput(inode);
 287                 return ERR_PTR(-ENOMEM);
 288         }
 289
 290         return dentry;
 291
 292  fail_rgd:
 293         gfs2_glock_dq_uninit(&rgd_gh);
 294
 295  fail_rindex:
 296         gfs2_glock_dq_uninit(&ri_gh);
 297
 298  fail:
 299         gfs2_glock_dq_uninit(&i_gh);
 300         return ERR_PTR(error);
 301 }
 302
 303 struct export_operations gfs2_export_ops = {
 304         .decode_fh = gfs2_decode_fh,
 305         .encode_fh = gfs2_encode_fh,
 306         .get_name = gfs2_get_name,
 307         .get_parent = gfs2_get_parent,
 308         .get_dentry = gfs2_get_dentry,
 309 };
 310