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, unsigned int length,
 117                             u64 offset, struct gfs2_inum_host *inum,
 118                             unsigned int type)
 119 {
 120         struct get_name_filldir *gnfd = (struct get_name_filldir *)opaque;
 121
 122         if (!gfs2_inum_equal(inum, &gnfd->inum))
 123                 return 0;
 124
 125         memcpy(gnfd->name, name, length);
 126         gnfd->name[length] = 0;
 127
 128         return 1;
 129 }
 130
 131 static int gfs2_get_name(struct dentry *parent, char *name,
 132                          struct dentry *child)
 133 {
 134         struct inode *dir = parent->d_inode;
 135         struct inode *inode = child->d_inode;
 136         struct gfs2_inode *dip, *ip;
 137         struct get_name_filldir gnfd;
 138         struct gfs2_holder gh;
 139         u64 offset = 0;
 140         int error;
 141
 142         if (!dir)
 143                 return -EINVAL;
 144
 145         if (!S_ISDIR(dir->i_mode) || !inode)
 146                 return -EINVAL;
 147
 148         dip = GFS2_I(dir);
 149         ip = GFS2_I(inode);
 150
 151         *name = 0;
 152         gnfd.inum = ip->i_num;
 153         gnfd.name = name;
 154
 155         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
 156         if (error)
 157                 return error;
 158
 159         error = gfs2_dir_read(dir, &offset, &gnfd, get_name_filldir);
 160
 161         gfs2_glock_dq_uninit(&gh);
 162
 163         if (!error && !*name)
 164                 error = -ENOENT;
 165
 166         return error;
 167 }
 168
 169 static struct dentry *gfs2_get_parent(struct dentry *child)
 170 {
 171         struct qstr dotdot;
 172         struct inode *inode;
 173         struct dentry *dentry;
 174
 175         gfs2_str2qstr(&dotdot, "..");
 176         inode = gfs2_lookupi(child->d_inode, &dotdot, 1, NULL);
 177
 178         if (!inode)
 179                 return ERR_PTR(-ENOENT);
 180         /*
 181          * In case of an error, @inode carries the error value, and we
 182          * have to return that as a(n invalid) pointer to dentry.
 183          */
 184         if (IS_ERR(inode))
 185                 return ERR_PTR(PTR_ERR(inode));
 186
 187         dentry = d_alloc_anon(inode);
 188         if (!dentry) {
 189                 iput(inode);
 190                 return ERR_PTR(-ENOMEM);
 191         }
 192
 193         dentry->d_op = &gfs2_dops;
 194         return dentry;
 195 }
 196
 197 static struct dentry *gfs2_get_dentry(struct super_block *sb, void *inum_obj)
 198 {
 199         struct gfs2_sbd *sdp = sb->s_fs_info;
 200         struct gfs2_fh_obj *fh_obj = (struct gfs2_fh_obj *)inum_obj;
 201         struct gfs2_inum_host *inum = &fh_obj->this;
 202         struct gfs2_holder i_gh, ri_gh, rgd_gh;
 203         struct gfs2_rgrpd *rgd;
 204         struct inode *inode;
 205         struct dentry *dentry;
 206         int error;
 207
 208         /* System files? */
 209
 210         inode = gfs2_ilookup(sb, inum);
 211         if (inode) {
 212                 if (GFS2_I(inode)->i_num.no_formal_ino != inum->no_formal_ino) {
 213                         iput(inode);
 214                         return ERR_PTR(-ESTALE);
 215                 }
 216                 goto out_inode;
 217         }
 218
 219         error = gfs2_glock_nq_num(sdp, inum->no_addr, &gfs2_inode_glops,
 220                                   LM_ST_SHARED, LM_FLAG_ANY | GL_LOCAL_EXCL,
 221                                   &i_gh);
 222         if (error)
 223                 return ERR_PTR(error);
 224
 225         error = gfs2_rindex_hold(sdp, &ri_gh);
 226         if (error)
 227                 goto fail;
 228
 229         error = -EINVAL;
 230         rgd = gfs2_blk2rgrpd(sdp, inum->no_addr);
 231         if (!rgd)
 232                 goto fail_rindex;
 233
 234         error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
 235         if (error)
 236                 goto fail_rindex;
 237
 238         error = -ESTALE;
 239         if (gfs2_get_block_type(rgd, inum->no_addr) != GFS2_BLKST_DINODE)
 240                 goto fail_rgd;
 241
 242         gfs2_glock_dq_uninit(&rgd_gh);
 243         gfs2_glock_dq_uninit(&ri_gh);
 244
 245         inode = gfs2_inode_lookup(sb, inum, fh_obj->imode);
 246         if (!inode)
 247                 goto fail;
 248         if (IS_ERR(inode)) {
 249                 error = PTR_ERR(inode);
 250                 goto fail;
 251         }
 252
 253         error = gfs2_inode_refresh(GFS2_I(inode));
 254         if (error) {
 255                 iput(inode);
 256                 goto fail;
 257         }
 258
 259         error = -EIO;
 260         if (GFS2_I(inode)->i_di.di_flags & GFS2_DIF_SYSTEM) {
 261                 iput(inode);
 262                 goto fail;
 263         }
 264
 265         gfs2_glock_dq_uninit(&i_gh);
 266
 267 out_inode:
 268         dentry = d_alloc_anon(inode);
 269         if (!dentry) {
 270                 iput(inode);
 271                 return ERR_PTR(-ENOMEM);
 272         }
 273
 274         dentry->d_op = &gfs2_dops;
 275         return dentry;
 276
 277 fail_rgd:
 278         gfs2_glock_dq_uninit(&rgd_gh);
 279
 280 fail_rindex:
 281         gfs2_glock_dq_uninit(&ri_gh);
 282
 283 fail:
 284         gfs2_glock_dq_uninit(&i_gh);
 285         return ERR_PTR(error);
 286 }
 287
 288 struct export_operations gfs2_export_ops = {
 289         .decode_fh = gfs2_decode_fh,
 290         .encode_fh = gfs2_encode_fh,
 291         .get_name = gfs2_get_name,
 292         .get_parent = gfs2_get_parent,
 293         .get_dentry = gfs2_get_dentry,
 294 };
 295