fs/gfs2/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/spinlock.h>
  11 #include <linux/completion.h>
  12 #include <linux/buffer_head.h>
  13 #include <linux/exportfs.h>
  14 #include <linux/gfs2_ondisk.h>
  15 #include <linux/crc32.h>
  16
  17 #include "gfs2.h"
  18 #include "incore.h"
  19 #include "dir.h"
  20 #include "glock.h"
  21 #include "glops.h"
  22 #include "inode.h"
  23 #include "super.h"
  24 #include "rgrp.h"
  25 #include "util.h"
  26
  27 #define GFS2_SMALL_FH_SIZE 4
  28 #define GFS2_LARGE_FH_SIZE 8
  29 #define GFS2_OLD_FH_SIZE 10
  30
  31 static int gfs2_encode_fh(struct inode *inode, __u32 *p, int *len,
  32                           struct inode *parent)
  33 {
  34         __be32 *fh = (__force __be32 *)p;
  35         struct super_block *sb = inode->i_sb;
  36         struct gfs2_inode *ip = GFS2_I(inode);
  37
  38         if (parent && (*len < GFS2_LARGE_FH_SIZE)) {
  39                 *len = GFS2_LARGE_FH_SIZE;
  40                 return FILEID_INVALID;
  41         } else if (*len < GFS2_SMALL_FH_SIZE) {
  42                 *len = GFS2_SMALL_FH_SIZE;
  43                 return FILEID_INVALID;
  44         }
  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 (!parent || inode == d_inode(sb->s_root))
  53                 return *len;
  54
  55         ip = GFS2_I(parent);
  56
  57         fh[4] = cpu_to_be32(ip->i_no_formal_ino >> 32);
  58         fh[5] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
  59         fh[6] = cpu_to_be32(ip->i_no_addr >> 32);
  60         fh[7] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
  61         *len = GFS2_LARGE_FH_SIZE;
  62
  63         return *len;
  64 }
  65
  66 struct get_name_filldir {
  67         struct dir_context ctx;
  68         struct gfs2_inum_host inum;
  69         char *name;
  70 };
  71
  72 static int get_name_filldir(struct dir_context *ctx, const char *name,
  73                             int length, loff_t offset, u64 inum,
  74                             unsigned int type)
  75 {
  76         struct get_name_filldir *gnfd =
  77                 container_of(ctx, struct get_name_filldir, ctx);
  78
  79         if (inum != gnfd->inum.no_addr)
  80                 return 0;
  81
  82         memcpy(gnfd->name, name, length);
  83         gnfd->name[length] = 0;
  84
  85         return 1;
  86 }
  87
  88 static int gfs2_get_name(struct dentry *parent, char *name,
  89                          struct dentry *child)
  90 {
  91         struct inode *dir = d_inode(parent);
  92         struct inode *inode = d_inode(child);
  93         struct gfs2_inode *dip, *ip;
  94         struct get_name_filldir gnfd = {
  95                 .ctx.actor = get_name_filldir,
  96                 .name = name
  97         };
  98         struct gfs2_holder gh;
  99         int error;
 100         struct file_ra_state f_ra = { .start = 0 };
 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
 115         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
 116         if (error)
 117                 return error;
 118
 119         error = gfs2_dir_read(dir, &gnfd.ctx, &f_ra);
 120
 121         gfs2_glock_dq_uninit(&gh);
 122
 123         if (!error && !*name)
 124                 error = -ENOENT;
 125
 126         return error;
 127 }
 128
 129 static struct dentry *gfs2_get_parent(struct dentry *child)
 130 {
 131         return d_obtain_alias(gfs2_lookupi(d_inode(child), &gfs2_qdotdot, 1));
 132 }
 133
 134 static struct dentry *gfs2_get_dentry(struct super_block *sb,
 135                                       struct gfs2_inum_host *inum)
 136 {
 137         struct gfs2_sbd *sdp = sb->s_fs_info;
 138         struct inode *inode;
 139
 140         inode = gfs2_ilookup(sb, inum->no_addr, 0);
 141         if (inode) {
 142                 if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
 143                         iput(inode);
 144                         return ERR_PTR(-ESTALE);
 145                 }
 146                 goto out_inode;
 147         }
 148
 149         inode = gfs2_lookup_by_inum(sdp, inum->no_addr, &inum->no_formal_ino,
 150                                     GFS2_BLKST_DINODE);
 151         if (IS_ERR(inode))
 152                 return ERR_CAST(inode);
 153
 154 out_inode:
 155         return d_obtain_alias(inode);
 156 }
 157
 158 static struct dentry *gfs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 159                 int fh_len, int fh_type)
 160 {
 161         struct gfs2_inum_host this;
 162         __be32 *fh = (__force __be32 *)fid->raw;
 163
 164         switch (fh_type) {
 165         case GFS2_SMALL_FH_SIZE:
 166         case GFS2_LARGE_FH_SIZE:
 167         case GFS2_OLD_FH_SIZE:
 168                 if (fh_len < GFS2_SMALL_FH_SIZE)
 169                         return NULL;
 170                 this.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
 171                 this.no_formal_ino |= be32_to_cpu(fh[1]);
 172                 this.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
 173                 this.no_addr |= be32_to_cpu(fh[3]);
 174                 return gfs2_get_dentry(sb, &this);
 175         default:
 176                 return NULL;
 177         }
 178 }
 179
 180 static struct dentry *gfs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 181                 int fh_len, int fh_type)
 182 {
 183         struct gfs2_inum_host parent;
 184         __be32 *fh = (__force __be32 *)fid->raw;
 185
 186         switch (fh_type) {
 187         case GFS2_LARGE_FH_SIZE:
 188         case GFS2_OLD_FH_SIZE:
 189                 if (fh_len < GFS2_LARGE_FH_SIZE)
 190                         return NULL;
 191                 parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
 192                 parent.no_formal_ino |= be32_to_cpu(fh[5]);
 193                 parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
 194                 parent.no_addr |= be32_to_cpu(fh[7]);
 195                 return gfs2_get_dentry(sb, &parent);
 196         default:
 197                 return NULL;
 198         }
 199 }
 200
 201 const struct export_operations gfs2_export_ops = {
 202         .encode_fh = gfs2_encode_fh,
 203         .fh_to_dentry = gfs2_fh_to_dentry,
 204         .fh_to_parent = gfs2_fh_to_parent,
 205         .get_name = gfs2_get_name,
 206         .get_parent = gfs2_get_parent,
 207 };
 208