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 GFS2_LARGE_FH_SIZE:
  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 GFS2_SMALL_FH_SIZE:
  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 < GFS2_SMALL_FH_SIZE ||
  76             (connectable && *len < GFS2_LARGE_FH_SIZE))
  77                 return 255;
  78
  79         fh[0] = ip->i_num.no_formal_ino >> 32;
  80         fh[0] = cpu_to_be32(fh[0]);
  81         fh[1] = ip->i_num.no_formal_ino & 0xFFFFFFFF;
  82         fh[1] = cpu_to_be32(fh[1]);
  83         fh[2] = ip->i_num.no_addr >> 32;
  84         fh[2] = cpu_to_be32(fh[2]);
  85         fh[3] = ip->i_num.no_addr & 0xFFFFFFFF;
  86         fh[3] = cpu_to_be32(fh[3]);
  87         *len = GFS2_SMALL_FH_SIZE;
  88
  89         if (!connectable || inode == sb->s_root->d_inode)
  90                 return *len;
  91
  92         spin_lock(&dentry->d_lock);
  93         inode = dentry->d_parent->d_inode;
  94         ip = GFS2_I(inode);
  95         igrab(inode);
  96         spin_unlock(&dentry->d_lock);
  97
  98         fh[4] = ip->i_num.no_formal_ino >> 32;
  99         fh[4] = cpu_to_be32(fh[4]);
 100         fh[5] = ip->i_num.no_formal_ino & 0xFFFFFFFF;
 101         fh[5] = cpu_to_be32(fh[5]);
 102         fh[6] = ip->i_num.no_addr >> 32;
 103         fh[6] = cpu_to_be32(fh[6]);
 104         fh[7] = ip->i_num.no_addr & 0xFFFFFFFF;
 105         fh[7] = cpu_to_be32(fh[7]);
 106
 107         fh[8]  = cpu_to_be32(inode->i_mode);
 108         fh[9]  = 0;     /* pad to double word */
 109         *len = GFS2_LARGE_FH_SIZE;
 110
 111         iput(inode);
 112
 113         return *len;
 114 }
 115
 116 struct get_name_filldir {
 117         struct gfs2_inum inum;
 118         char *name;
 119 };
 120
 121 static int get_name_filldir(void *opaque, const char *name, unsigned int length,
 122                             u64 offset, struct gfs2_inum *inum,
 123                             unsigned int type)
 124 {
 125         struct get_name_filldir *gnfd = (struct get_name_filldir *)opaque;
 126
 127         if (!gfs2_inum_equal(inum, &gnfd->inum))
 128                 return 0;
 129
 130         memcpy(gnfd->name, name, length);
 131         gnfd->name[length] = 0;
 132
 133         return 1;
 134 }
 135
 136 static int gfs2_get_name(struct dentry *parent, char *name,
 137                          struct dentry *child)
 138 {
 139         struct inode *dir = parent->d_inode;
 140         struct inode *inode = child->d_inode;
 141         struct gfs2_inode *dip, *ip;
 142         struct get_name_filldir gnfd;
 143         struct gfs2_holder gh;
 144         u64 offset = 0;
 145         int error;
 146
 147         if (!dir)
 148                 return -EINVAL;
 149
 150         if (!S_ISDIR(dir->i_mode) || !inode)
 151                 return -EINVAL;
 152
 153         dip = GFS2_I(dir);
 154         ip = GFS2_I(inode);
 155
 156         *name = 0;
 157         gnfd.inum = ip->i_num;
 158         gnfd.name = name;
 159
 160         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
 161         if (error)
 162                 return error;
 163
 164         error = gfs2_dir_read(dir, &offset, &gnfd, get_name_filldir);
 165
 166         gfs2_glock_dq_uninit(&gh);
 167
 168         if (!error && !*name)
 169                 error = -ENOENT;
 170
 171         return error;
 172 }
 173
 174 static struct dentry *gfs2_get_parent(struct dentry *child)
 175 {
 176         struct qstr dotdot;
 177         struct inode *inode;
 178         struct dentry *dentry;
 179
 180         gfs2_str2qstr(&dotdot, "..");
 181         inode = gfs2_lookupi(child->d_inode, &dotdot, 1, NULL);
 182
 183         if (!inode)
 184                 return ERR_PTR(-ENOENT);
 185         /*
 186          * In case of an error, @inode carries the error value, and we
 187          * have to return that as a(n invalid) pointer to dentry.
 188          */
 189         if (IS_ERR(inode))
 190                 return ERR_PTR(PTR_ERR(inode));
 191
 192         dentry = d_alloc_anon(inode);
 193         if (!dentry) {
 194                 iput(inode);
 195                 return ERR_PTR(-ENOMEM);
 196         }
 197
 198         return dentry;
 199 }
 200
 201 static struct dentry *gfs2_get_dentry(struct super_block *sb, void *inum_obj)
 202 {
 203         struct gfs2_sbd *sdp = sb->s_fs_info;
 204         struct gfs2_fh_obj *fh_obj = (struct gfs2_fh_obj *)inum_obj;
 205         struct gfs2_inum *inum = &fh_obj->this;
 206         struct gfs2_holder i_gh, ri_gh, rgd_gh;
 207         struct gfs2_rgrpd *rgd;
 208         struct inode *inode;
 209         struct dentry *dentry;
 210         int error;
 211
 212         /* System files? */
 213
 214         inode = gfs2_ilookup(sb, inum);
 215         if (inode) {
 216                 if (GFS2_I(inode)->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, inum->no_addr, &gfs2_inode_glops,
 224                                   LM_ST_SHARED, LM_FLAG_ANY | GL_LOCAL_EXCL,
 225                                   &i_gh);
 226         if (error)
 227                 return ERR_PTR(error);
 228
 229         error = gfs2_rindex_hold(sdp, &ri_gh);
 230         if (error)
 231                 goto fail;
 232
 233         error = -EINVAL;
 234         rgd = gfs2_blk2rgrpd(sdp, inum->no_addr);
 235         if (!rgd)
 236                 goto fail_rindex;
 237
 238         error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
 239         if (error)
 240                 goto fail_rindex;
 241
 242         error = -ESTALE;
 243         if (gfs2_get_block_type(rgd, inum->no_addr) != GFS2_BLKST_DINODE)
 244                 goto fail_rgd;
 245
 246         gfs2_glock_dq_uninit(&rgd_gh);
 247         gfs2_glock_dq_uninit(&ri_gh);
 248
 249         inode = gfs2_inode_lookup(sb, inum, fh_obj->imode);
 250         if (!inode)
 251                 goto fail;
 252         if (IS_ERR(inode)) {
 253                 error = PTR_ERR(inode);
 254                 goto fail;
 255         }
 256
 257         error = gfs2_inode_refresh(GFS2_I(inode));
 258         if (error) {
 259                 iput(inode);
 260                 goto fail;
 261         }
 262
 263         error = -EIO;
 264         if (GFS2_I(inode)->i_di.di_flags & GFS2_DIF_SYSTEM) {
 265                 iput(inode);
 266                 goto fail;
 267         }
 268
 269         gfs2_glock_dq_uninit(&i_gh);
 270
 271 out_inode:
 272         dentry = d_alloc_anon(inode);
 273         if (!dentry) {
 274                 iput(inode);
 275                 return ERR_PTR(-ENOMEM);
 276         }
 277
 278         return dentry;
 279
 280 fail_rgd:
 281         gfs2_glock_dq_uninit(&rgd_gh);
 282
 283 fail_rindex:
 284         gfs2_glock_dq_uninit(&ri_gh);
 285
 286 fail:
 287         gfs2_glock_dq_uninit(&i_gh);
 288         return ERR_PTR(error);
 289 }
 290
 291 struct export_operations gfs2_export_ops = {
 292         .decode_fh = gfs2_decode_fh,
 293         .encode_fh = gfs2_encode_fh,
 294         .get_name = gfs2_get_name,
 295         .get_parent = gfs2_get_parent,
 296         .get_dentry = gfs2_get_dentry,
 297 };
 298