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_fstype.h"
  27 #include "rgrp.h"
  28 #include "util.h"
  29
  30 #define GFS2_SMALL_FH_SIZE 4
  31 #define GFS2_LARGE_FH_SIZE 8
  32 #define GFS2_OLD_FH_SIZE 10
  33
  34 static int gfs2_encode_fh(struct dentry *dentry, __u32 *p, int *len,
  35                           int connectable)
  36 {
  37         __be32 *fh = (__force __be32 *)p;
  38         struct inode *inode = dentry->d_inode;
  39         struct super_block *sb = inode->i_sb;
  40         struct gfs2_inode *ip = GFS2_I(inode);
  41
  42         if (*len < GFS2_SMALL_FH_SIZE ||
  43             (connectable && *len < GFS2_LARGE_FH_SIZE))
  44                 return 255;
  45
  46         fh[0] = cpu_to_be32(ip->i_no_formal_ino >> 32);
  47         fh[1] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
  48         fh[2] = cpu_to_be32(ip->i_no_addr >> 32);
  49         fh[3] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
  50         *len = GFS2_SMALL_FH_SIZE;
  51
  52         if (!connectable || inode == sb->s_root->d_inode)
  53                 return *len;
  54
  55         spin_lock(&dentry->d_lock);
  56         inode = dentry->d_parent->d_inode;
  57         ip = GFS2_I(inode);
  58         igrab(inode);
  59         spin_unlock(&dentry->d_lock);
  60
  61         fh[4] = cpu_to_be32(ip->i_no_formal_ino >> 32);
  62         fh[5] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
  63         fh[6] = cpu_to_be32(ip->i_no_addr >> 32);
  64         fh[7] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
  65         *len = GFS2_LARGE_FH_SIZE;
  66
  67         iput(inode);
  68
  69         return *len;
  70 }
  71
  72 struct get_name_filldir {
  73         struct gfs2_inum_host inum;
  74         char *name;
  75 };
  76
  77 static int get_name_filldir(void *opaque, const char *name, int length,
  78                             loff_t offset, u64 inum, unsigned int type)
  79 {
  80         struct get_name_filldir *gnfd = opaque;
  81
  82         if (inum != gnfd->inum.no_addr)
  83                 return 0;
  84
  85         memcpy(gnfd->name, name, length);
  86         gnfd->name[length] = 0;
  87
  88         return 1;
  89 }
  90
  91 static int gfs2_get_name(struct dentry *parent, char *name,
  92                          struct dentry *child)
  93 {
  94         struct inode *dir = parent->d_inode;
  95         struct inode *inode = child->d_inode;
  96         struct gfs2_inode *dip, *ip;
  97         struct get_name_filldir gnfd;
  98         struct gfs2_holder gh;
  99         u64 offset = 0;
 100         int error;
 101
 102         if (!dir)
 103                 return -EINVAL;
 104
 105         if (!S_ISDIR(dir->i_mode) || !inode)
 106                 return -EINVAL;
 107
 108         dip = GFS2_I(dir);
 109         ip = GFS2_I(inode);
 110
 111         *name = 0;
 112         gnfd.inum.no_addr = ip->i_no_addr;
 113         gnfd.inum.no_formal_ino = ip->i_no_formal_ino;
 114         gnfd.name = name;
 115
 116         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
 117         if (error)
 118                 return error;
 119
 120         error = gfs2_dir_read(dir, &offset, &gnfd, get_name_filldir);
 121
 122         gfs2_glock_dq_uninit(&gh);
 123
 124         if (!error && !*name)
 125                 error = -ENOENT;
 126
 127         return error;
 128 }
 129
 130 static struct dentry *gfs2_get_parent(struct dentry *child)
 131 {
 132         struct qstr dotdot;
 133         struct inode *inode;
 134         struct dentry *dentry;
 135
 136         gfs2_str2qstr(&dotdot, "..");
 137         inode = gfs2_lookupi(child->d_inode, &dotdot, 1);
 138
 139         if (!inode)
 140                 return ERR_PTR(-ENOENT);
 141         /*
 142          * In case of an error, @inode carries the error value, and we
 143          * have to return that as a(n invalid) pointer to dentry.
 144          */
 145         if (IS_ERR(inode))
 146                 return ERR_CAST(inode);
 147
 148         dentry = d_alloc_anon(inode);
 149         if (!dentry) {
 150                 iput(inode);
 151                 return ERR_PTR(-ENOMEM);
 152         }
 153
 154         dentry->d_op = &gfs2_dops;
 155         return dentry;
 156 }
 157
 158 static struct dentry *gfs2_get_dentry(struct super_block *sb,
 159                 struct gfs2_inum_host *inum)
 160 {
 161         struct gfs2_sbd *sdp = sb->s_fs_info;
 162         struct gfs2_holder i_gh, ri_gh, rgd_gh;
 163         struct gfs2_rgrpd *rgd;
 164         struct inode *inode;
 165         struct dentry *dentry;
 166         int error;
 167
 168         /* System files? */
 169
 170         inode = gfs2_ilookup(sb, inum->no_addr);
 171         if (inode) {
 172                 if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
 173                         iput(inode);
 174                         return ERR_PTR(-ESTALE);
 175                 }
 176                 goto out_inode;
 177         }
 178
 179         error = gfs2_glock_nq_num(sdp, inum->no_addr, &gfs2_inode_glops,
 180                                   LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
 181         if (error)
 182                 return ERR_PTR(error);
 183
 184         error = gfs2_rindex_hold(sdp, &ri_gh);
 185         if (error)
 186                 goto fail;
 187
 188         error = -EINVAL;
 189         rgd = gfs2_blk2rgrpd(sdp, inum->no_addr);
 190         if (!rgd)
 191                 goto fail_rindex;
 192
 193         error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
 194         if (error)
 195                 goto fail_rindex;
 196
 197         error = -ESTALE;
 198         if (gfs2_get_block_type(rgd, inum->no_addr) != GFS2_BLKST_DINODE)
 199                 goto fail_rgd;
 200
 201         gfs2_glock_dq_uninit(&rgd_gh);
 202         gfs2_glock_dq_uninit(&ri_gh);
 203
 204         inode = gfs2_inode_lookup(sb, DT_UNKNOWN,
 205                                         inum->no_addr,
 206                                         0, 0);
 207         if (IS_ERR(inode)) {
 208                 error = PTR_ERR(inode);
 209                 goto fail;
 210         }
 211
 212         error = gfs2_inode_refresh(GFS2_I(inode));
 213         if (error) {
 214                 iput(inode);
 215                 goto fail;
 216         }
 217
 218         /* Pick up the works we bypass in gfs2_inode_lookup */
 219         if (inode->i_state & I_NEW)
 220                 gfs2_set_iop(inode);
 221
 222         if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
 223                 iput(inode);
 224                 goto fail;
 225         }
 226
 227         error = -EIO;
 228         if (GFS2_I(inode)->i_di.di_flags & GFS2_DIF_SYSTEM) {
 229                 iput(inode);
 230                 goto fail;
 231         }
 232
 233         gfs2_glock_dq_uninit(&i_gh);
 234
 235 out_inode:
 236         dentry = d_alloc_anon(inode);
 237         if (!dentry) {
 238                 iput(inode);
 239                 return ERR_PTR(-ENOMEM);
 240         }
 241
 242         dentry->d_op = &gfs2_dops;
 243         return dentry;
 244
 245 fail_rgd:
 246         gfs2_glock_dq_uninit(&rgd_gh);
 247
 248 fail_rindex:
 249         gfs2_glock_dq_uninit(&ri_gh);
 250
 251 fail:
 252         gfs2_glock_dq_uninit(&i_gh);
 253         return ERR_PTR(error);
 254 }
 255
 256 static struct dentry *gfs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 257                 int fh_len, int fh_type)
 258 {
 259         struct gfs2_inum_host this;
 260         __be32 *fh = (__force __be32 *)fid->raw;
 261
 262         switch (fh_type) {
 263         case GFS2_SMALL_FH_SIZE:
 264         case GFS2_LARGE_FH_SIZE:
 265         case GFS2_OLD_FH_SIZE:
 266                 this.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
 267                 this.no_formal_ino |= be32_to_cpu(fh[1]);
 268                 this.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
 269                 this.no_addr |= be32_to_cpu(fh[3]);
 270                 return gfs2_get_dentry(sb, &this);
 271         default:
 272                 return NULL;
 273         }
 274 }
 275
 276 static struct dentry *gfs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 277                 int fh_len, int fh_type)
 278 {
 279         struct gfs2_inum_host parent;
 280         __be32 *fh = (__force __be32 *)fid->raw;
 281
 282         switch (fh_type) {
 283         case GFS2_LARGE_FH_SIZE:
 284         case GFS2_OLD_FH_SIZE:
 285                 parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
 286                 parent.no_formal_ino |= be32_to_cpu(fh[5]);
 287                 parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
 288                 parent.no_addr |= be32_to_cpu(fh[7]);
 289                 return gfs2_get_dentry(sb, &parent);
 290         default:
 291                 return NULL;
 292         }
 293 }
 294
 295 const struct export_operations gfs2_export_ops = {
 296         .encode_fh = gfs2_encode_fh,
 297         .fh_to_dentry = gfs2_fh_to_dentry,
 298         .fh_to_parent = gfs2_fh_to_parent,
 299         .get_name = gfs2_get_name,
 300         .get_parent = gfs2_get_parent,
 301 };
 302