fs/gfs2/ops_export.c - linux - Git at Google

 /*
  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
  * Copyright (C) 2004-2006 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 version 2.
  */

 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/completion.h>
 #include <linux/buffer_head.h>
 #include <linux/exportfs.h>
 #include <linux/gfs2_ondisk.h>
 #include <linux/crc32.h>
 #include <linux/lm_interface.h>

 #include "gfs2.h"
 #include "incore.h"
 #include "dir.h"
 #include "glock.h"
 #include "glops.h"
 #include "inode.h"
 #include "ops_dentry.h"
 #include "ops_fstype.h"
 #include "rgrp.h"
 #include "util.h"

 #define GFS2_SMALL_FH_SIZE 4
 #define GFS2_LARGE_FH_SIZE 8
 #define GFS2_OLD_FH_SIZE 10

 static int gfs2_encode_fh(struct dentry *dentry, __u32 *p, int *len,
 			  int connectable)
 {
 	__be32 *fh = (__force __be32 *)p;
 	struct inode *inode = dentry->d_inode;
 	struct super_block *sb = inode->i_sb;
 	struct gfs2_inode *ip = GFS2_I(inode);

 	if (*len < GFS2_SMALL_FH_SIZE ||
 	    (connectable && *len < GFS2_LARGE_FH_SIZE))
 		return 255;

 	fh[0] = cpu_to_be32(ip->i_no_formal_ino >> 32);
 	fh[1] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
 	fh[2] = cpu_to_be32(ip->i_no_addr >> 32);
 	fh[3] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
 	*len = GFS2_SMALL_FH_SIZE;

 	if (!connectable || inode == sb->s_root->d_inode)
 		return *len;

 	spin_lock(&dentry->d_lock);
 	inode = dentry->d_parent->d_inode;
 	ip = GFS2_I(inode);
 	igrab(inode);
 	spin_unlock(&dentry->d_lock);

 	fh[4] = cpu_to_be32(ip->i_no_formal_ino >> 32);
 	fh[5] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
 	fh[6] = cpu_to_be32(ip->i_no_addr >> 32);
 	fh[7] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
 	*len = GFS2_LARGE_FH_SIZE;

 	iput(inode);

 	return *len;
 }

 struct get_name_filldir {
 	struct gfs2_inum_host inum;
 	char *name;
 };

 static int get_name_filldir(void *opaque, const char *name, int length,
 			    loff_t offset, u64 inum, unsigned int type)
 {
 	struct get_name_filldir *gnfd = opaque;

 	if (inum != gnfd->inum.no_addr)
 		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;
 	u64 offset = 0;
 	int error;

 	if (!dir)
 		return -EINVAL;

 	if (!S_ISDIR(dir->i_mode) || !inode)
 		return -EINVAL;

 	dip = GFS2_I(dir);
 	ip = GFS2_I(inode);

 	*name = 0;
 	gnfd.inum.no_addr = ip->i_no_addr;
 	gnfd.inum.no_formal_ino = ip->i_no_formal_ino;
 	gnfd.name = name;

 	error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
 	if (error)
 		return error;

 	error = gfs2_dir_read(dir, &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;
 	struct inode *inode;
 	struct dentry *dentry;

 	gfs2_str2qstr(&dotdot, "..");
 	inode = gfs2_lookupi(child->d_inode, &dotdot, 1, NULL);

 	if (!inode)
 		return ERR_PTR(-ENOENT);
 	/*
 	 * In case of an error, @inode carries the error value, and we
 	 * have to return that as a(n invalid) pointer to dentry.
 	 */
 	if (IS_ERR(inode))
 		return ERR_CAST(inode);

 	dentry = d_alloc_anon(inode);
 	if (!dentry) {
 		iput(inode);
 		return ERR_PTR(-ENOMEM);
 	}

 	dentry->d_op = &gfs2_dops;
 	return dentry;
 }

 static struct dentry *gfs2_get_dentry(struct super_block *sb,
 		struct gfs2_inum_host *inum)
 {
 	struct gfs2_sbd *sdp = sb->s_fs_info;
 	struct gfs2_holder i_gh, ri_gh, rgd_gh;
 	struct gfs2_rgrpd *rgd;
 	struct inode *inode;
 	struct dentry *dentry;
 	int error;

 	/* System files? */

 	inode = gfs2_ilookup(sb, inum->no_addr);
 	if (inode) {
 		if (GFS2_I(inode)->i_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, &i_gh);
 	if (error)
 		return ERR_PTR(error);

 	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);

 	inode = gfs2_inode_lookup(sb, DT_UNKNOWN,
 					inum->no_addr,
 					0, 0);
 	if (!inode)
 		goto fail;
 	if (IS_ERR(inode)) {
 		error = PTR_ERR(inode);
 		goto fail;
 	}

 	error = gfs2_inode_refresh(GFS2_I(inode));
 	if (error) {
 		iput(inode);
 		goto fail;
 	}

 	/* Pick up the works we bypass in gfs2_inode_lookup */
 	if (inode->i_state & I_NEW)
 		gfs2_set_iop(inode);

 	if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
 		iput(inode);
 		goto fail;
 	}

 	error = -EIO;
 	if (GFS2_I(inode)->i_di.di_flags & GFS2_DIF_SYSTEM) {
 		iput(inode);
 		goto fail;
 	}

 	gfs2_glock_dq_uninit(&i_gh);

 out_inode:
 	dentry = d_alloc_anon(inode);
 	if (!dentry) {
 		iput(inode);
 		return ERR_PTR(-ENOMEM);
 	}

 	dentry->d_op = &gfs2_dops;
 	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);
 }

 static struct dentry *gfs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 		int fh_len, int fh_type)
 {
 	struct gfs2_inum_host this;
 	__be32 *fh = (__force __be32 *)fid->raw;

 	switch (fh_type) {
 	case GFS2_SMALL_FH_SIZE:
 	case GFS2_LARGE_FH_SIZE:
 	case GFS2_OLD_FH_SIZE:
 		this.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
 		this.no_formal_ino |= be32_to_cpu(fh[1]);
 		this.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
 		this.no_addr |= be32_to_cpu(fh[3]);
 		return gfs2_get_dentry(sb, &this);
 	default:
 		return NULL;
 	}
 }

 static struct dentry *gfs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 		int fh_len, int fh_type)
 {
 	struct gfs2_inum_host parent;
 	__be32 *fh = (__force __be32 *)fid->raw;

 	switch (fh_type) {
 	case GFS2_LARGE_FH_SIZE:
 	case GFS2_OLD_FH_SIZE:
 		parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
 		parent.no_formal_ino |= be32_to_cpu(fh[5]);
 		parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
 		parent.no_addr |= be32_to_cpu(fh[7]);
 		return gfs2_get_dentry(sb, &parent);
 	default:
 		return NULL;
 	}
 }

 const struct export_operations gfs2_export_ops = {
 	.encode_fh = gfs2_encode_fh,
 	.fh_to_dentry = gfs2_fh_to_dentry,
 	.fh_to_parent = gfs2_fh_to_parent,
 	.get_name = gfs2_get_name,
 	.get_parent = gfs2_get_parent,
 };
	/*
	* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
	* Copyright (C) 2004-2006 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 version 2.
	*/

	#include <linux/slab.h>
	#include <linux/spinlock.h>
	#include <linux/completion.h>
	#include <linux/buffer_head.h>
	#include <linux/exportfs.h>
	#include <linux/gfs2_ondisk.h>
	#include <linux/crc32.h>
	#include <linux/lm_interface.h>

	#include "gfs2.h"
	#include "incore.h"
	#include "dir.h"
	#include "glock.h"
	#include "glops.h"
	#include "inode.h"
	#include "ops_dentry.h"
	#include "ops_fstype.h"
	#include "rgrp.h"
	#include "util.h"

	#define GFS2_SMALL_FH_SIZE 4
	#define GFS2_LARGE_FH_SIZE 8
	#define GFS2_OLD_FH_SIZE 10

	static int gfs2_encode_fh(struct dentry dentry, __u32 p, int *len,
	int connectable)
	{
	__be32 fh = (__force __be32 )p;
	struct inode *inode = dentry->d_inode;
	struct super_block *sb = inode->i_sb;
	struct gfs2_inode *ip = GFS2_I(inode);

	if (*len < GFS2_SMALL_FH_SIZE \|\|
	(connectable && *len < GFS2_LARGE_FH_SIZE))
	return 255;

	fh[0] = cpu_to_be32(ip->i_no_formal_ino >> 32);
	fh[1] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
	fh[2] = cpu_to_be32(ip->i_no_addr >> 32);
	fh[3] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
	*len = GFS2_SMALL_FH_SIZE;

	if (!connectable \|\| inode == sb->s_root->d_inode)
	return *len;

	spin_lock(&dentry->d_lock);
	inode = dentry->d_parent->d_inode;
	ip = GFS2_I(inode);
	igrab(inode);
	spin_unlock(&dentry->d_lock);

	fh[4] = cpu_to_be32(ip->i_no_formal_ino >> 32);
	fh[5] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
	fh[6] = cpu_to_be32(ip->i_no_addr >> 32);
	fh[7] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
	*len = GFS2_LARGE_FH_SIZE;

	iput(inode);

	return *len;
	}

	struct get_name_filldir {
	struct gfs2_inum_host inum;
	char *name;
	};

	static int get_name_filldir(void opaque, const char name, int length,
	loff_t offset, u64 inum, unsigned int type)
	{
	struct get_name_filldir *gnfd = opaque;

	if (inum != gnfd->inum.no_addr)
	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;
	u64 offset = 0;
	int error;

	if (!dir)
	return -EINVAL;

	if (!S_ISDIR(dir->i_mode) \|\| !inode)
	return -EINVAL;

	dip = GFS2_I(dir);
	ip = GFS2_I(inode);

	*name = 0;
	gnfd.inum.no_addr = ip->i_no_addr;
	gnfd.inum.no_formal_ino = ip->i_no_formal_ino;
	gnfd.name = name;

	error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
	if (error)
	return error;

	error = gfs2_dir_read(dir, &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;
	struct inode *inode;
	struct dentry *dentry;

	gfs2_str2qstr(&dotdot, "..");
	inode = gfs2_lookupi(child->d_inode, &dotdot, 1, NULL);

	if (!inode)
	return ERR_PTR(-ENOENT);
	/*
	* In case of an error, @inode carries the error value, and we
	* have to return that as a(n invalid) pointer to dentry.
	*/
	if (IS_ERR(inode))
	return ERR_CAST(inode);

	dentry = d_alloc_anon(inode);
	if (!dentry) {
	iput(inode);
	return ERR_PTR(-ENOMEM);
	}

	dentry->d_op = &gfs2_dops;
	return dentry;
	}

	static struct dentry gfs2_get_dentry(struct super_block sb,
	struct gfs2_inum_host *inum)
	{
	struct gfs2_sbd *sdp = sb->s_fs_info;
	struct gfs2_holder i_gh, ri_gh, rgd_gh;
	struct gfs2_rgrpd *rgd;
	struct inode *inode;
	struct dentry *dentry;
	int error;

	/* System files? */

	inode = gfs2_ilookup(sb, inum->no_addr);
	if (inode) {
	if (GFS2_I(inode)->i_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, &i_gh);
	if (error)
	return ERR_PTR(error);

	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);

	inode = gfs2_inode_lookup(sb, DT_UNKNOWN,
	inum->no_addr,
	0, 0);
	if (!inode)
	goto fail;
	if (IS_ERR(inode)) {
	error = PTR_ERR(inode);
	goto fail;
	}

	error = gfs2_inode_refresh(GFS2_I(inode));
	if (error) {
	iput(inode);
	goto fail;
	}

	/* Pick up the works we bypass in gfs2_inode_lookup */
	if (inode->i_state & I_NEW)
	gfs2_set_iop(inode);

	if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
	iput(inode);
	goto fail;
	}

	error = -EIO;
	if (GFS2_I(inode)->i_di.di_flags & GFS2_DIF_SYSTEM) {
	iput(inode);
	goto fail;
	}

	gfs2_glock_dq_uninit(&i_gh);

	out_inode:
	dentry = d_alloc_anon(inode);
	if (!dentry) {
	iput(inode);
	return ERR_PTR(-ENOMEM);
	}

	dentry->d_op = &gfs2_dops;
	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);
	}

	static struct dentry gfs2_fh_to_dentry(struct super_block sb, struct fid *fid,
	int fh_len, int fh_type)
	{
	struct gfs2_inum_host this;
	__be32 fh = (__force __be32 )fid->raw;

	switch (fh_type) {
	case GFS2_SMALL_FH_SIZE:
	case GFS2_LARGE_FH_SIZE:
	case GFS2_OLD_FH_SIZE:
	this.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
	this.no_formal_ino \|= be32_to_cpu(fh[1]);
	this.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
	this.no_addr \|= be32_to_cpu(fh[3]);
	return gfs2_get_dentry(sb, &this);
	default:
	return NULL;
	}
	}

	static struct dentry gfs2_fh_to_parent(struct super_block sb, struct fid *fid,
	int fh_len, int fh_type)
	{
	struct gfs2_inum_host parent;
	__be32 fh = (__force __be32 )fid->raw;

	switch (fh_type) {
	case GFS2_LARGE_FH_SIZE:
	case GFS2_OLD_FH_SIZE:
	parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
	parent.no_formal_ino \|= be32_to_cpu(fh[5]);
	parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
	parent.no_addr \|= be32_to_cpu(fh[7]);
	return gfs2_get_dentry(sb, &parent);
	default:
	return NULL;
	}
	}

	const struct export_operations gfs2_export_ops = {
	.encode_fh = gfs2_encode_fh,
	.fh_to_dentry = gfs2_fh_to_dentry,
	.fh_to_parent = gfs2_fh_to_parent,
	.get_name = gfs2_get_name,
	.get_parent = gfs2_get_parent,
	};