linux/fs/gfs2/ops_export.c

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/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License v.2.
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/gfs2_ondisk.h>
#include <asm/semaphore.h>
#include "gfs2.h"
#include "lm_interface.h"
#include "incore.h"
#include "dir.h"
#include "glock.h"
#include "glops.h"
#include "inode.h"
#include "ops_export.h"
#include "rgrp.h"
static struct dentry *gfs2_decode_fh(struct super_block *sb,
__u32 *fh,
int fh_len,
int fh_type,
int (*acceptable)(void *context,
struct dentry *dentry),
void *context)
{
struct gfs2_inum this, parent;
if (fh_type != fh_len)
return NULL;
memset(&parent, 0, sizeof(struct gfs2_inum));
switch (fh_type) {
case 8:
parent.no_formal_ino = ((uint64_t)be32_to_cpu(fh[4])) << 32;
parent.no_formal_ino |= be32_to_cpu(fh[5]);
parent.no_addr = ((uint64_t)be32_to_cpu(fh[6])) << 32;
parent.no_addr |= be32_to_cpu(fh[7]);
case 4:
this.no_formal_ino = ((uint64_t)be32_to_cpu(fh[0])) << 32;
this.no_formal_ino |= be32_to_cpu(fh[1]);
this.no_addr = ((uint64_t)be32_to_cpu(fh[2])) << 32;
this.no_addr |= be32_to_cpu(fh[3]);
break;
default:
return NULL;
}
return gfs2_export_ops.find_exported_dentry(sb, &this, &parent,
acceptable, context);
}
static int gfs2_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
int connectable)
{
struct inode *inode = dentry->d_inode;
struct gfs2_inode *ip = inode->u.generic_ip;
struct gfs2_sbd *sdp = ip->i_sbd;
if (*len < 4 || (connectable && *len < 8))
return 255;
fh[0] = ip->i_num.no_formal_ino >> 32;
fh[0] = cpu_to_be32(fh[0]);
fh[1] = ip->i_num.no_formal_ino & 0xFFFFFFFF;
fh[1] = cpu_to_be32(fh[1]);
fh[2] = ip->i_num.no_addr >> 32;
fh[2] = cpu_to_be32(fh[2]);
fh[3] = ip->i_num.no_addr & 0xFFFFFFFF;
fh[3] = cpu_to_be32(fh[3]);
*len = 4;
if (!connectable || ip == sdp->sd_root_dir->u.generic_ip)
return *len;
spin_lock(&dentry->d_lock);
inode = dentry->d_parent->d_inode;
ip = inode->u.generic_ip;
gfs2_inode_hold(ip);
spin_unlock(&dentry->d_lock);
fh[4] = ip->i_num.no_formal_ino >> 32;
fh[4] = cpu_to_be32(fh[4]);
fh[5] = ip->i_num.no_formal_ino & 0xFFFFFFFF;
fh[5] = cpu_to_be32(fh[5]);
fh[6] = ip->i_num.no_addr >> 32;
fh[6] = cpu_to_be32(fh[6]);
fh[7] = ip->i_num.no_addr & 0xFFFFFFFF;
fh[7] = cpu_to_be32(fh[7]);
*len = 8;
gfs2_inode_put(ip);
return *len;
}
struct get_name_filldir {
struct gfs2_inum inum;
char *name;
};
static int get_name_filldir(void *opaque, const char *name, unsigned int length,
uint64_t offset, struct gfs2_inum *inum,
unsigned int type)
{
struct get_name_filldir *gnfd = (struct get_name_filldir *)opaque;
if (!gfs2_inum_equal(inum, &gnfd->inum))
return 0;
memcpy(gnfd->name, name, length);
gnfd->name[length] = 0;
return 1;
}
static int gfs2_get_name(struct dentry *parent, char *name,
struct dentry *child)
{
struct inode *dir = parent->d_inode;
struct inode *inode = child->d_inode;
struct gfs2_inode *dip, *ip;
struct get_name_filldir gnfd;
struct gfs2_holder gh;
uint64_t offset = 0;
int error;
if (!dir)
return -EINVAL;
if (!S_ISDIR(dir->i_mode) || !inode)
return -EINVAL;
dip = dir->u.generic_ip;
ip = inode->u.generic_ip;
*name = 0;
gnfd.inum = ip->i_num;
gnfd.name = name;
error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
if (error)
return error;
error = gfs2_dir_read(dip, &offset, &gnfd, get_name_filldir);
gfs2_glock_dq_uninit(&gh);
if (!error && !*name)
error = -ENOENT;
return error;
}
static struct dentry *gfs2_get_parent(struct dentry *child)
{
struct qstr dotdot = { .name = "..", .len = 2 };
struct inode *inode;
struct dentry *dentry;
int error;
error = gfs2_lookupi(child->d_inode, &dotdot, 1, &inode);
if (error)
return ERR_PTR(error);
dentry = d_alloc_anon(inode);
if (!dentry) {
iput(inode);
return ERR_PTR(-ENOMEM);
}
return dentry;
}
static struct dentry *gfs2_get_dentry(struct super_block *sb, void *inum_p)
{
struct gfs2_sbd *sdp = sb->s_fs_info;
struct gfs2_inum *inum = (struct gfs2_inum *)inum_p;
struct gfs2_holder i_gh, ri_gh, rgd_gh;
struct gfs2_rgrpd *rgd;
struct gfs2_inode *ip;
struct inode *inode;
struct dentry *dentry;
int error;
/* System files? */
inode = gfs2_iget(sb, inum);
if (inode) {
ip = inode->u.generic_ip;
if (ip->i_num.no_formal_ino != inum->no_formal_ino) {
iput(inode);
return ERR_PTR(-ESTALE);
}
goto out_inode;
}
error = gfs2_glock_nq_num(sdp,
inum->no_addr, &gfs2_inode_glops,
LM_ST_SHARED, LM_FLAG_ANY | GL_LOCAL_EXCL,
&i_gh);
if (error)
return ERR_PTR(error);
error = gfs2_inode_get(i_gh.gh_gl, inum, NO_CREATE, &ip);
if (error)
goto fail;
if (ip)
goto out_ip;
error = gfs2_rindex_hold(sdp, &ri_gh);
if (error)
goto fail;
error = -EINVAL;
rgd = gfs2_blk2rgrpd(sdp, inum->no_addr);
if (!rgd)
goto fail_rindex;
error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
if (error)
goto fail_rindex;
error = -ESTALE;
if (gfs2_get_block_type(rgd, inum->no_addr) != GFS2_BLKST_DINODE)
goto fail_rgd;
gfs2_glock_dq_uninit(&rgd_gh);
gfs2_glock_dq_uninit(&ri_gh);
error = gfs2_inode_get(i_gh.gh_gl, inum, CREATE, &ip);
if (error)
goto fail;
error = gfs2_inode_refresh(ip);
if (error) {
gfs2_inode_put(ip);
goto fail;
}
out_ip:
error = -EIO;
if (ip->i_di.di_flags & GFS2_DIF_SYSTEM) {
gfs2_inode_put(ip);
goto fail;
}
gfs2_glock_dq_uninit(&i_gh);
inode = gfs2_ip2v(ip);
gfs2_inode_put(ip);
if (!inode)
return ERR_PTR(-ENOMEM);
out_inode:
dentry = d_alloc_anon(inode);
if (!dentry) {
iput(inode);
return ERR_PTR(-ENOMEM);
}
return dentry;
fail_rgd:
gfs2_glock_dq_uninit(&rgd_gh);
fail_rindex:
gfs2_glock_dq_uninit(&ri_gh);
fail:
gfs2_glock_dq_uninit(&i_gh);
return ERR_PTR(error);
}
struct export_operations gfs2_export_ops = {
.decode_fh = gfs2_decode_fh,
.encode_fh = gfs2_encode_fh,
.get_name = gfs2_get_name,
.get_parent = gfs2_get_parent,
.get_dentry = gfs2_get_dentry,
};