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 255;
  41         } else if (*len < GFS2_SMALL_FH_SIZE) {
  42                 *len = GFS2_SMALL_FH_SIZE;
  43                 return 255;
  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 == sb->s_root->d_inode)
  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 gfs2_inum_host inum;
  68         char *name;
  69 };
  70
  71 static int get_name_filldir(void *opaque, const char *name, int length,
  72                             loff_t offset, u64 inum, unsigned int type)
  73 {
  74         struct get_name_filldir *gnfd = opaque;
  75
  76         if (inum != gnfd->inum.no_addr)
  77                 return 0;
  78
  79         memcpy(gnfd->name, name, length);
  80         gnfd->name[length] = 0;
  81
  82         return 1;
  83 }
  84
  85 static int gfs2_get_name(struct dentry *parent, char *name,
  86                          struct dentry *child)
  87 {
  88         struct inode *dir = parent->d_inode;
  89         struct inode *inode = child->d_inode;
  90         struct gfs2_inode *dip, *ip;
  91         struct get_name_filldir gnfd;
  92         struct gfs2_holder gh;
  93         u64 offset = 0;
  94         int error;
  95         struct file_ra_state f_ra = { .start = 0 };
  96
  97         if (!dir)
  98                 return -EINVAL;
  99
 100         if (!S_ISDIR(dir->i_mode) || !inode)
 101                 return -EINVAL;
 102
 103         dip = GFS2_I(dir);
 104         ip = GFS2_I(inode);
 105
 106         *name = 0;
 107         gnfd.inum.no_addr = ip->i_no_addr;
 108         gnfd.inum.no_formal_ino = ip->i_no_formal_ino;
 109         gnfd.name = name;
 110
 111         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
 112         if (error)
 113                 return error;
 114
 115         error = gfs2_dir_read(dir, &offset, &gnfd, get_name_filldir, &f_ra);
 116
 117         gfs2_glock_dq_uninit(&gh);
 118
 119         if (!error && !*name)
 120                 error = -ENOENT;
 121
 122         return error;
 123 }
 124
 125 static struct dentry *gfs2_get_parent(struct dentry *child)
 126 {
 127         return d_obtain_alias(gfs2_lookupi(child->d_inode, &gfs2_qdotdot, 1));
 128 }
 129
 130 static struct dentry *gfs2_get_dentry(struct super_block *sb,
 131                                       struct gfs2_inum_host *inum)
 132 {
 133         struct gfs2_sbd *sdp = sb->s_fs_info;
 134         struct inode *inode;
 135
 136         inode = gfs2_ilookup(sb, inum->no_addr, 0);
 137         if (inode) {
 138                 if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
 139                         iput(inode);
 140                         return ERR_PTR(-ESTALE);
 141                 }
 142                 goto out_inode;
 143         }
 144
 145         inode = gfs2_lookup_by_inum(sdp, inum->no_addr, &inum->no_formal_ino,
 146                                     GFS2_BLKST_DINODE);
 147         if (IS_ERR(inode))
 148                 return ERR_CAST(inode);
 149
 150 out_inode:
 151         return d_obtain_alias(inode);
 152 }
 153
 154 static struct dentry *gfs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 155                 int fh_len, int fh_type)
 156 {
 157         struct gfs2_inum_host this;
 158         __be32 *fh = (__force __be32 *)fid->raw;
 159
 160         switch (fh_type) {
 161         case GFS2_SMALL_FH_SIZE:
 162         case GFS2_LARGE_FH_SIZE:
 163         case GFS2_OLD_FH_SIZE:
 164                 this.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
 165                 this.no_formal_ino |= be32_to_cpu(fh[1]);
 166                 this.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
 167                 this.no_addr |= be32_to_cpu(fh[3]);
 168                 return gfs2_get_dentry(sb, &this);
 169         default:
 170                 return NULL;
 171         }
 172 }
 173
 174 static struct dentry *gfs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 175                 int fh_len, int fh_type)
 176 {
 177         struct gfs2_inum_host parent;
 178         __be32 *fh = (__force __be32 *)fid->raw;
 179
 180         switch (fh_type) {
 181         case GFS2_LARGE_FH_SIZE:
 182         case GFS2_OLD_FH_SIZE:
 183                 parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
 184                 parent.no_formal_ino |= be32_to_cpu(fh[5]);
 185                 parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
 186                 parent.no_addr |= be32_to_cpu(fh[7]);
 187                 return gfs2_get_dentry(sb, &parent);
 188         default:
 189                 return NULL;
 190         }
 191 }
 192
 193 const struct export_operations gfs2_export_ops = {
 194         .encode_fh = gfs2_encode_fh,
 195         .fh_to_dentry = gfs2_fh_to_dentry,
 196         .fh_to_parent = gfs2_fh_to_parent,
 197         .get_name = gfs2_get_name,
 198         .get_parent = gfs2_get_parent,
 199 };
 200