release/src-rt-6.x/linux/linux-2.6/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/slab.h>
  11 #include <linux/spinlock.h>
  12 #include <linux/completion.h>
  13 #include <linux/buffer_head.h>
  14 #include <linux/exportfs.h>
  15 #include <linux/gfs2_ondisk.h>
  16 #include <linux/crc32.h>
  17 #include <linux/lm_interface.h>
  18
  19 #include "gfs2.h"
  20 #include "incore.h"
  21 #include "dir.h"
  22 #include "glock.h"
  23 #include "glops.h"
  24 #include "inode.h"
  25 #include "ops_dentry.h"
  26 #include "ops_export.h"
  27 #include "rgrp.h"
  28 #include "util.h"
  29
  30 static int gfs2_encode_fh(struct dentry *dentry, __u32 *p, int *len,
  31                           int connectable)
  32 {
  33         __be32 *fh = (__force __be32 *)p;
  34         struct inode *inode = dentry->d_inode;
  35         struct super_block *sb = inode->i_sb;
  36         struct gfs2_inode *ip = GFS2_I(inode);
  37
  38         if (*len < GFS2_SMALL_FH_SIZE ||
  39             (connectable && *len < GFS2_LARGE_FH_SIZE))
  40                 return 255;
  41
  42         fh[0] = cpu_to_be32(ip->i_num.no_formal_ino >> 32);
  43         fh[1] = cpu_to_be32(ip->i_num.no_formal_ino & 0xFFFFFFFF);
  44         fh[2] = cpu_to_be32(ip->i_num.no_addr >> 32);
  45         fh[3] = cpu_to_be32(ip->i_num.no_addr & 0xFFFFFFFF);
  46         *len = GFS2_SMALL_FH_SIZE;
  47
  48         if (!connectable || inode == sb->s_root->d_inode)
  49                 return *len;
  50
  51         spin_lock(&dentry->d_lock);
  52         inode = dentry->d_parent->d_inode;
  53         ip = GFS2_I(inode);
  54         igrab(inode);
  55         spin_unlock(&dentry->d_lock);
  56
  57         fh[4] = cpu_to_be32(ip->i_num.no_formal_ino >> 32);
  58         fh[5] = cpu_to_be32(ip->i_num.no_formal_ino & 0xFFFFFFFF);
  59         fh[6] = cpu_to_be32(ip->i_num.no_addr >> 32);
  60         fh[7] = cpu_to_be32(ip->i_num.no_addr & 0xFFFFFFFF);
  61
  62         fh[8]  = cpu_to_be32(inode->i_mode);
  63         fh[9]  = 0;     /* pad to double word */
  64         *len = GFS2_LARGE_FH_SIZE;
  65
  66         iput(inode);
  67
  68         return *len;
  69 }
  70
  71 struct get_name_filldir {
  72         struct gfs2_inum_host inum;
  73         char *name;
  74 };
  75
  76 static int get_name_filldir(void *opaque, const char *name, int length,
  77                             loff_t offset, u64 inum, unsigned int type)
  78 {
  79         struct get_name_filldir *gnfd = opaque;
  80
  81         if (inum != gnfd->inum.no_addr)
  82                 return 0;
  83
  84         memcpy(gnfd->name, name, length);
  85         gnfd->name[length] = 0;
  86
  87         return 1;
  88 }
  89
  90 static int gfs2_get_name(struct dentry *parent, char *name,
  91                          struct dentry *child)
  92 {
  93         struct inode *dir = parent->d_inode;
  94         struct inode *inode = child->d_inode;
  95         struct gfs2_inode *dip, *ip;
  96         struct get_name_filldir gnfd;
  97         struct gfs2_holder gh;
  98         u64 offset = 0;
  99         int error;
 100
 101         if (!dir)
 102                 return -EINVAL;
 103
 104         if (!S_ISDIR(dir->i_mode) || !inode)
 105                 return -EINVAL;
 106
 107         dip = GFS2_I(dir);
 108         ip = GFS2_I(inode);
 109
 110         *name = 0;
 111         gnfd.inum = ip->i_num;
 112         gnfd.name = name;
 113
 114         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
 115         if (error)
 116                 return error;
 117
 118         error = gfs2_dir_read(dir, &offset, &gnfd, get_name_filldir);
 119
 120         gfs2_glock_dq_uninit(&gh);
 121
 122         if (!error && !*name)
 123                 error = -ENOENT;
 124
 125         return error;
 126 }
 127
 128 static struct dentry *gfs2_get_parent(struct dentry *child)
 129 {
 130         struct qstr dotdot;
 131         struct inode *inode;
 132         struct dentry *dentry;
 133
 134         gfs2_str2qstr(&dotdot, "..");
 135         inode = gfs2_lookupi(child->d_inode, &dotdot, 1, NULL);
 136
 137         if (!inode)
 138                 return ERR_PTR(-ENOENT);
 139         /*
 140          * In case of an error, @inode carries the error value, and we
 141          * have to return that as a(n invalid) pointer to dentry.
 142          */
 143         if (IS_ERR(inode))
 144                 return ERR_PTR(PTR_ERR(inode));
 145
 146         dentry = d_alloc_anon(inode);
 147         if (!dentry) {
 148                 iput(inode);
 149                 return ERR_PTR(-ENOMEM);
 150         }
 151
 152         dentry->d_op = &gfs2_dops;
 153         return dentry;
 154 }
 155
 156 static struct dentry *gfs2_get_dentry(struct super_block *sb,
 157                 struct gfs2_inum_host *inum)
 158 {
 159         struct gfs2_sbd *sdp = sb->s_fs_info;
 160         struct gfs2_fh_obj *fh_obj = (struct gfs2_fh_obj *)inum_obj;
 161         struct gfs2_holder i_gh, ri_gh, rgd_gh;
 162         struct gfs2_rgrpd *rgd;
 163         struct inode *inode;
 164         struct dentry *dentry;
 165         int error;
 166
 167         /* System files? */
 168
 169         inode = gfs2_ilookup(sb, inum);
 170         if (inode) {
 171                 if (GFS2_I(inode)->i_num.no_formal_ino != inum->no_formal_ino) {
 172                         iput(inode);
 173                         return ERR_PTR(-ESTALE);
 174                 }
 175                 goto out_inode;
 176         }
 177
 178         error = gfs2_glock_nq_num(sdp, inum->no_addr, &gfs2_inode_glops,
 179                                   LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
 180         if (error)
 181                 return ERR_PTR(error);
 182
 183         error = gfs2_rindex_hold(sdp, &ri_gh);
 184         if (error)
 185                 goto fail;
 186
 187         error = -EINVAL;
 188         rgd = gfs2_blk2rgrpd(sdp, inum->no_addr);
 189         if (!rgd)
 190                 goto fail_rindex;
 191
 192         error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
 193         if (error)
 194                 goto fail_rindex;
 195
 196         error = -ESTALE;
 197         if (gfs2_get_block_type(rgd, inum->no_addr) != GFS2_BLKST_DINODE)
 198                 goto fail_rgd;
 199
 200         gfs2_glock_dq_uninit(&rgd_gh);
 201         gfs2_glock_dq_uninit(&ri_gh);
 202
 203         inode = gfs2_inode_lookup(sb, inum, fh_obj->imode);
 204         if (!inode)
 205                 goto fail;
 206         if (IS_ERR(inode)) {
 207                 error = PTR_ERR(inode);
 208                 goto fail;
 209         }
 210
 211         error = gfs2_inode_refresh(GFS2_I(inode));
 212         if (error) {
 213                 iput(inode);
 214                 goto fail;
 215         }
 216
 217         error = -EIO;
 218         if (GFS2_I(inode)->i_di.di_flags & GFS2_DIF_SYSTEM) {
 219                 iput(inode);
 220                 goto fail;
 221         }
 222
 223         gfs2_glock_dq_uninit(&i_gh);
 224
 225 out_inode:
 226         dentry = d_alloc_anon(inode);
 227         if (!dentry) {
 228                 iput(inode);
 229                 return ERR_PTR(-ENOMEM);
 230         }
 231
 232         dentry->d_op = &gfs2_dops;
 233         return dentry;
 234
 235 fail_rgd:
 236         gfs2_glock_dq_uninit(&rgd_gh);
 237
 238 fail_rindex:
 239         gfs2_glock_dq_uninit(&ri_gh);
 240
 241 fail:
 242         gfs2_glock_dq_uninit(&i_gh);
 243         return ERR_PTR(error);
 244 }
 245
 246 static struct dentry *gfs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 247                 int fh_len, int fh_type)
 248 {
 249         struct gfs2_inum_host this;
 250         __be32 *fh = (__force __be32 *)fid->raw;
 251
 252         switch (fh_type) {
 253         case GFS2_SMALL_FH_SIZE:
 254         case GFS2_LARGE_FH_SIZE:
 255         case GFS2_OLD_FH_SIZE:
 256                 this.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
 257                 this.no_formal_ino |= be32_to_cpu(fh[1]);
 258                 this.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
 259                 this.no_addr |= be32_to_cpu(fh[3]);
 260                 return gfs2_get_dentry(sb, &this);
 261         default:
 262                 return NULL;
 263         }
 264 }
 265
 266 static struct dentry *gfs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 267                 int fh_len, int fh_type)
 268 {
 269         struct gfs2_inum_host parent;
 270         __be32 *fh = (__force __be32 *)fid->raw;
 271
 272         switch (fh_type) {
 273         case GFS2_LARGE_FH_SIZE:
 274         case GFS2_OLD_FH_SIZE:
 275                 parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
 276                 parent.no_formal_ino |= be32_to_cpu(fh[5]);
 277                 parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
 278                 parent.no_addr |= be32_to_cpu(fh[7]);
 279                 return gfs2_get_dentry(sb, &parent);
 280         default:
 281                 return NULL;
 282         }
 283 }
 284
 285 const struct export_operations gfs2_export_ops = {
 286         .encode_fh = gfs2_encode_fh,
 287         .fh_to_dentry = gfs2_fh_to_dentry,
 288         .fh_to_parent = gfs2_fh_to_parent,
 289         .get_name = gfs2_get_name,
 290         .get_parent = gfs2_get_parent,
 291 };
 292