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) 2004-2006 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/gfs2_ondisk.h>
  15 #include <linux/crc32.h>
  16 #include <linux/lm_interface.h>
  17
  18 #include "gfs2.h"
  19 #include "incore.h"
  20 #include "dir.h"
  21 #include "glock.h"
  22 #include "glops.h"
  23 #include "inode.h"
  24 #include "ops_dentry.h"
  25 #include "ops_fstype.h"
  26 #include "rgrp.h"
  27 #include "util.h"
  28
  29 #define GFS2_SMALL_FH_SIZE 4
  30 #define GFS2_LARGE_FH_SIZE 10
  31
  32 struct gfs2_fh_obj {
  33         struct gfs2_inum_host this;
  34         u32 imode;
  35 };
  36
  37 static struct dentry *gfs2_decode_fh(struct super_block *sb,
  38                                      __u32 *p,
  39                                      int fh_len,
  40                                      int fh_type,
  41                                      int (*acceptable)(void *context,
  42                                                        struct dentry *dentry),
  43                                      void *context)
  44 {
  45         __be32 *fh = (__force __be32 *)p;
  46         struct gfs2_fh_obj fh_obj;
  47         struct gfs2_inum_host *this, parent;
  48
  49         this            = &fh_obj.this;
  50         fh_obj.imode    = DT_UNKNOWN;
  51         memset(&parent, 0, sizeof(struct gfs2_inum));
  52
  53         switch (fh_len) {
  54         case GFS2_LARGE_FH_SIZE:
  55                 parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
  56                 parent.no_formal_ino |= be32_to_cpu(fh[5]);
  57                 parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
  58                 parent.no_addr |= be32_to_cpu(fh[7]);
  59                 fh_obj.imode = be32_to_cpu(fh[8]);
  60         case GFS2_SMALL_FH_SIZE:
  61                 this->no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
  62                 this->no_formal_ino |= be32_to_cpu(fh[1]);
  63                 this->no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
  64                 this->no_addr |= be32_to_cpu(fh[3]);
  65                 break;
  66         default:
  67                 return NULL;
  68         }
  69
  70         return gfs2_export_ops.find_exported_dentry(sb, &fh_obj, &parent,
  71                                                     acceptable, context);
  72 }
  73
  74 static int gfs2_encode_fh(struct dentry *dentry, __u32 *p, int *len,
  75                           int connectable)
  76 {
  77         __be32 *fh = (__force __be32 *)p;
  78         struct inode *inode = dentry->d_inode;
  79         struct super_block *sb = inode->i_sb;
  80         struct gfs2_inode *ip = GFS2_I(inode);
  81
  82         if (*len < GFS2_SMALL_FH_SIZE ||
  83             (connectable && *len < GFS2_LARGE_FH_SIZE))
  84                 return 255;
  85
  86         fh[0] = cpu_to_be32(ip->i_no_formal_ino >> 32);
  87         fh[1] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
  88         fh[2] = cpu_to_be32(ip->i_no_addr >> 32);
  89         fh[3] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
  90         *len = GFS2_SMALL_FH_SIZE;
  91
  92         if (!connectable || inode == sb->s_root->d_inode)
  93                 return *len;
  94
  95         spin_lock(&dentry->d_lock);
  96         inode = dentry->d_parent->d_inode;
  97         ip = GFS2_I(inode);
  98         igrab(inode);
  99         spin_unlock(&dentry->d_lock);
 100
 101         fh[4] = cpu_to_be32(ip->i_no_formal_ino >> 32);
 102         fh[5] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
 103         fh[6] = cpu_to_be32(ip->i_no_addr >> 32);
 104         fh[7] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
 105
 106         fh[8]  = cpu_to_be32(inode->i_mode);
 107         fh[9]  = 0;     /* pad to double word */
 108         *len = GFS2_LARGE_FH_SIZE;
 109
 110         iput(inode);
 111
 112         return *len;
 113 }
 114
 115 struct get_name_filldir {
 116         struct gfs2_inum_host inum;
 117         char *name;
 118 };
 119
 120 static int get_name_filldir(void *opaque, const char *name, int length,
 121                             loff_t offset, u64 inum, unsigned int type)
 122 {
 123         struct get_name_filldir *gnfd = opaque;
 124
 125         if (inum != gnfd->inum.no_addr)
 126                 return 0;
 127
 128         memcpy(gnfd->name, name, length);
 129         gnfd->name[length] = 0;
 130
 131         return 1;
 132 }
 133
 134 static int gfs2_get_name(struct dentry *parent, char *name,
 135                          struct dentry *child)
 136 {
 137         struct inode *dir = parent->d_inode;
 138         struct inode *inode = child->d_inode;
 139         struct gfs2_inode *dip, *ip;
 140         struct get_name_filldir gnfd;
 141         struct gfs2_holder gh;
 142         u64 offset = 0;
 143         int error;
 144
 145         if (!dir)
 146                 return -EINVAL;
 147
 148         if (!S_ISDIR(dir->i_mode) || !inode)
 149                 return -EINVAL;
 150
 151         dip = GFS2_I(dir);
 152         ip = GFS2_I(inode);
 153
 154         *name = 0;
 155         gnfd.inum.no_addr = ip->i_no_addr;
 156         gnfd.inum.no_formal_ino = ip->i_no_formal_ino;
 157         gnfd.name = name;
 158
 159         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
 160         if (error)
 161                 return error;
 162
 163         error = gfs2_dir_read(dir, &offset, &gnfd, get_name_filldir);
 164
 165         gfs2_glock_dq_uninit(&gh);
 166
 167         if (!error && !*name)
 168                 error = -ENOENT;
 169
 170         return error;
 171 }
 172
 173 static struct dentry *gfs2_get_parent(struct dentry *child)
 174 {
 175         struct qstr dotdot;
 176         struct inode *inode;
 177         struct dentry *dentry;
 178
 179         gfs2_str2qstr(&dotdot, "..");
 180         inode = gfs2_lookupi(child->d_inode, &dotdot, 1, NULL);
 181
 182         if (!inode)
 183                 return ERR_PTR(-ENOENT);
 184         /*
 185          * In case of an error, @inode carries the error value, and we
 186          * have to return that as a(n invalid) pointer to dentry.
 187          */
 188         if (IS_ERR(inode))
 189                 return ERR_PTR(PTR_ERR(inode));
 190
 191         dentry = d_alloc_anon(inode);
 192         if (!dentry) {
 193                 iput(inode);
 194                 return ERR_PTR(-ENOMEM);
 195         }
 196
 197         dentry->d_op = &gfs2_dops;
 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_host *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->no_addr);
 215         if (inode) {
 216                 if (GFS2_I(inode)->i_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, &i_gh);
 225         if (error)
 226                 return ERR_PTR(error);
 227
 228         error = gfs2_rindex_hold(sdp, &ri_gh);
 229         if (error)
 230                 goto fail;
 231
 232         error = -EINVAL;
 233         rgd = gfs2_blk2rgrpd(sdp, inum->no_addr);
 234         if (!rgd)
 235                 goto fail_rindex;
 236
 237         error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
 238         if (error)
 239                 goto fail_rindex;
 240
 241         error = -ESTALE;
 242         if (gfs2_get_block_type(rgd, inum->no_addr) != GFS2_BLKST_DINODE)
 243                 goto fail_rgd;
 244
 245         gfs2_glock_dq_uninit(&rgd_gh);
 246         gfs2_glock_dq_uninit(&ri_gh);
 247
 248         inode = gfs2_inode_lookup(sb, fh_obj->imode,
 249                                         inum->no_addr,
 250                                         inum->no_formal_ino);
 251         if (!inode)
 252                 goto fail;
 253         if (IS_ERR(inode)) {
 254                 error = PTR_ERR(inode);
 255                 goto fail;
 256         }
 257
 258         error = gfs2_inode_refresh(GFS2_I(inode));
 259         if (error) {
 260                 iput(inode);
 261                 goto fail;
 262         }
 263         if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
 264                 iput(inode);
 265                 goto fail;
 266         }
 267
 268         error = -EIO;
 269         if (GFS2_I(inode)->i_di.di_flags & GFS2_DIF_SYSTEM) {
 270                 iput(inode);
 271                 goto fail;
 272         }
 273
 274         gfs2_glock_dq_uninit(&i_gh);
 275
 276 out_inode:
 277         dentry = d_alloc_anon(inode);
 278         if (!dentry) {
 279                 iput(inode);
 280                 return ERR_PTR(-ENOMEM);
 281         }
 282
 283         dentry->d_op = &gfs2_dops;
 284         return dentry;
 285
 286 fail_rgd:
 287         gfs2_glock_dq_uninit(&rgd_gh);
 288
 289 fail_rindex:
 290         gfs2_glock_dq_uninit(&ri_gh);
 291
 292 fail:
 293         gfs2_glock_dq_uninit(&i_gh);
 294         return ERR_PTR(error);
 295 }
 296
 297 struct export_operations gfs2_export_ops = {
 298         .decode_fh = gfs2_decode_fh,
 299         .encode_fh = gfs2_encode_fh,
 300         .get_name = gfs2_get_name,
 301         .get_parent = gfs2_get_parent,
 302         .get_dentry = gfs2_get_dentry,
 303 };
 304