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 #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 struct dentry *gfs2_decode_fh(struct super_block *sb,
  31                                      __u32 *p,
  32                                      int fh_len,
  33                                      int fh_type,
  34                                      int (*acceptable)(void *context,
  35                                                        struct dentry *dentry),
  36                                      void *context)
  37 {
  38         __be32 *fh = (__force __be32 *)p;
  39         struct gfs2_fh_obj fh_obj;
  40         struct gfs2_inum_host *this, parent;
  41
  42         if (fh_type != fh_len)
  43                 return NULL;
  44
  45         this            = &fh_obj.this;
  46         fh_obj.imode    = DT_UNKNOWN;
  47         memset(&parent, 0, sizeof(struct gfs2_inum));
  48
  49         switch (fh_type) {
  50         case GFS2_LARGE_FH_SIZE:
  51                 parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
  52                 parent.no_formal_ino |= be32_to_cpu(fh[5]);
  53                 parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
  54                 parent.no_addr |= be32_to_cpu(fh[7]);
  55                 fh_obj.imode = be32_to_cpu(fh[8]);
  56         case GFS2_SMALL_FH_SIZE:
  57                 this->no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
  58                 this->no_formal_ino |= be32_to_cpu(fh[1]);
  59                 this->no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
  60                 this->no_addr |= be32_to_cpu(fh[3]);
  61                 break;
  62         default:
  63                 return NULL;
  64         }
  65
  66         return gfs2_export_ops.find_exported_dentry(sb, &fh_obj, &parent,
  67                                                     acceptable, context);
  68 }
  69
  70 static int gfs2_encode_fh(struct dentry *dentry, __u32 *p, int *len,
  71                           int connectable)
  72 {
  73         __be32 *fh = (__force __be32 *)p;
  74         struct inode *inode = dentry->d_inode;
  75         struct super_block *sb = inode->i_sb;
  76         struct gfs2_inode *ip = GFS2_I(inode);
  77
  78         if (*len < GFS2_SMALL_FH_SIZE ||
  79             (connectable && *len < GFS2_LARGE_FH_SIZE))
  80                 return 255;
  81
  82         fh[0] = cpu_to_be32(ip->i_num.no_formal_ino >> 32);
  83         fh[1] = cpu_to_be32(ip->i_num.no_formal_ino & 0xFFFFFFFF);
  84         fh[2] = cpu_to_be32(ip->i_num.no_addr >> 32);
  85         fh[3] = cpu_to_be32(ip->i_num.no_addr & 0xFFFFFFFF);
  86         *len = GFS2_SMALL_FH_SIZE;
  87
  88         if (!connectable || inode == sb->s_root->d_inode)
  89                 return *len;
  90
  91         spin_lock(&dentry->d_lock);
  92         inode = dentry->d_parent->d_inode;
  93         ip = GFS2_I(inode);
  94         igrab(inode);
  95         spin_unlock(&dentry->d_lock);
  96
  97         fh[4] = cpu_to_be32(ip->i_num.no_formal_ino >> 32);
  98         fh[5] = cpu_to_be32(ip->i_num.no_formal_ino & 0xFFFFFFFF);
  99         fh[6] = cpu_to_be32(ip->i_num.no_addr >> 32);
 100         fh[7] = cpu_to_be32(ip->i_num.no_addr & 0xFFFFFFFF);
 101
 102         fh[8]  = cpu_to_be32(inode->i_mode);
 103         fh[9]  = 0;     /* pad to double word */
 104         *len = GFS2_LARGE_FH_SIZE;
 105
 106         iput(inode);
 107
 108         return *len;
 109 }
 110
 111 struct get_name_filldir {
 112         struct gfs2_inum_host inum;
 113         char *name;
 114 };
 115
 116 static int get_name_filldir(void *opaque, const char *name, int length,
 117                             loff_t offset, u64 inum, unsigned int type)
 118 {
 119         struct get_name_filldir *gnfd = opaque;
 120
 121         if (inum != gnfd->inum.no_addr)
 122                 return 0;
 123
 124         memcpy(gnfd->name, name, length);
 125         gnfd->name[length] = 0;
 126
 127         return 1;
 128 }
 129
 130 static int gfs2_get_name(struct dentry *parent, char *name,
 131                          struct dentry *child)
 132 {
 133         struct inode *dir = parent->d_inode;
 134         struct inode *inode = child->d_inode;
 135         struct gfs2_inode *dip, *ip;
 136         struct get_name_filldir gnfd;
 137         struct gfs2_holder gh;
 138         u64 offset = 0;
 139         int error;
 140
 141         if (!dir)
 142                 return -EINVAL;
 143
 144         if (!S_ISDIR(dir->i_mode) || !inode)
 145                 return -EINVAL;
 146
 147         dip = GFS2_I(dir);
 148         ip = GFS2_I(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(dir, &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 qstr dotdot;
 171         struct inode *inode;
 172         struct dentry *dentry;
 173
 174         gfs2_str2qstr(&dotdot, "..");
 175         inode = gfs2_lookupi(child->d_inode, &dotdot, 1, NULL);
 176
 177         if (!inode)
 178                 return ERR_PTR(-ENOENT);
 179         /*
 180          * In case of an error, @inode carries the error value, and we
 181          * have to return that as a(n invalid) pointer to dentry.
 182          */
 183         if (IS_ERR(inode))
 184                 return ERR_PTR(PTR_ERR(inode));
 185
 186         dentry = d_alloc_anon(inode);
 187         if (!dentry) {
 188                 iput(inode);
 189                 return ERR_PTR(-ENOMEM);
 190         }
 191
 192         dentry->d_op = &gfs2_dops;
 193         return dentry;
 194 }
 195
 196 static struct dentry *gfs2_get_dentry(struct super_block *sb, void *inum_obj)
 197 {
 198         struct gfs2_sbd *sdp = sb->s_fs_info;
 199         struct gfs2_fh_obj *fh_obj = (struct gfs2_fh_obj *)inum_obj;
 200         struct gfs2_inum_host *inum = &fh_obj->this;
 201         struct gfs2_holder i_gh, ri_gh, rgd_gh;
 202         struct gfs2_rgrpd *rgd;
 203         struct inode *inode;
 204         struct dentry *dentry;
 205         int error;
 206
 207         /* System files? */
 208
 209         inode = gfs2_ilookup(sb, inum);
 210         if (inode) {
 211                 if (GFS2_I(inode)->i_num.no_formal_ino != inum->no_formal_ino) {
 212                         iput(inode);
 213                         return ERR_PTR(-ESTALE);
 214                 }
 215                 goto out_inode;
 216         }
 217
 218         error = gfs2_glock_nq_num(sdp, inum->no_addr, &gfs2_inode_glops,
 219                                   LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
 220         if (error)
 221                 return ERR_PTR(error);
 222
 223         error = gfs2_rindex_hold(sdp, &ri_gh);
 224         if (error)
 225                 goto fail;
 226
 227         error = -EINVAL;
 228         rgd = gfs2_blk2rgrpd(sdp, inum->no_addr);
 229         if (!rgd)
 230                 goto fail_rindex;
 231
 232         error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
 233         if (error)
 234                 goto fail_rindex;
 235
 236         error = -ESTALE;
 237         if (gfs2_get_block_type(rgd, inum->no_addr) != GFS2_BLKST_DINODE)
 238                 goto fail_rgd;
 239
 240         gfs2_glock_dq_uninit(&rgd_gh);
 241         gfs2_glock_dq_uninit(&ri_gh);
 242
 243         inode = gfs2_inode_lookup(sb, inum, fh_obj->imode);
 244         if (!inode)
 245                 goto fail;
 246         if (IS_ERR(inode)) {
 247                 error = PTR_ERR(inode);
 248                 goto fail;
 249         }
 250
 251         error = gfs2_inode_refresh(GFS2_I(inode));
 252         if (error) {
 253                 iput(inode);
 254                 goto fail;
 255         }
 256
 257         error = -EIO;
 258         if (GFS2_I(inode)->i_di.di_flags & GFS2_DIF_SYSTEM) {
 259                 iput(inode);
 260                 goto fail;
 261         }
 262
 263         gfs2_glock_dq_uninit(&i_gh);
 264
 265 out_inode:
 266         dentry = d_alloc_anon(inode);
 267         if (!dentry) {
 268                 iput(inode);
 269                 return ERR_PTR(-ENOMEM);
 270         }
 271
 272         dentry->d_op = &gfs2_dops;
 273         return dentry;
 274
 275 fail_rgd:
 276         gfs2_glock_dq_uninit(&rgd_gh);
 277
 278 fail_rindex:
 279         gfs2_glock_dq_uninit(&ri_gh);
 280
 281 fail:
 282         gfs2_glock_dq_uninit(&i_gh);
 283         return ERR_PTR(error);
 284 }
 285
 286 struct export_operations gfs2_export_ops = {
 287         .decode_fh = gfs2_decode_fh,
 288         .encode_fh = gfs2_encode_fh,
 289         .get_name = gfs2_get_name,
 290         .get_parent = gfs2_get_parent,
 291         .get_dentry = gfs2_get_dentry,
 292 };
 293