[mirror_ubuntu-artful-kernel.git] / fs / gfs2 / ops_export.c

/*
 * 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 struct dentry *gfs2_decode_fh(struct super_block *sb,
				     __u32 *p,
				     int fh_len,
				     int fh_type,
				     int (*acceptable)(void *context,
						       struct dentry *dentry),
				     void *context)
{
	__be32 *fh = (__force __be32 *)p;
	struct gfs2_inum_host inum, parent;

	memset(&parent, 0, sizeof(struct gfs2_inum));

	switch (fh_len) {
	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]);
	case GFS2_SMALL_FH_SIZE:
		inum.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
		inum.no_formal_ino |= be32_to_cpu(fh[1]);
		inum.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
		inum.no_addr |= be32_to_cpu(fh[3]);
		break;
	default:
		return NULL;
	}

	return gfs2_export_ops.find_exported_dentry(sb, &inum, &parent,
						    acceptable, context);
}

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_PTR(PTR_ERR(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, void *inum_obj)
{
	struct gfs2_sbd *sdp = sb->s_fs_info;
	struct gfs2_inum_host *inum = inum_obj;
	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);
}

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,
};
Commit	Line	Data
b3b94faa DT	1	/*
b3b94faa DT	2	* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
3a8a9a10	3	* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
b3b94faa DT	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
e9fc2aa0	7	* of the GNU General Public License version 2.
b3b94faa DT	8	*/
b3b94faa DT	9
b3b94faa DT	10	#include <linux/slab.h>
	11	#include <linux/spinlock.h>
	12	#include <linux/completion.h>
	13	#include <linux/buffer_head.h>
a5694255	14	#include <linux/exportfs.h>
5c676f6d	15	#include <linux/gfs2_ondisk.h>
71b86f56	16	#include <linux/crc32.h>
7d308590	17	#include <linux/lm_interface.h>
b3b94faa DT	18
b3b94faa DT	19	#include "gfs2.h"
5c676f6d	20	#include "incore.h"
b3b94faa DT	21	#include "dir.h"
	22	#include "glock.h"
	23	#include "glops.h"
	24	#include "inode.h"
70831465	25	#include "ops_dentry.h"
bb8d8a6f	26	#include "ops_fstype.h"
b3b94faa	27	#include "rgrp.h"
c752666c	28	#include "util.h"
b3b94faa	29
bb8d8a6f	30	#define GFS2_SMALL_FH_SIZE 4
35dcc52e	31	#define GFS2_LARGE_FH_SIZE 8
3ebf4490	32	#define GFS2_OLD_FH_SIZE 10
bb8d8a6f	33
b3b94faa	34	static struct dentry gfs2_decode_fh(struct super_block sb,
b44b84d7	35	__u32 *p,
b3b94faa DT	36	int fh_len,
	37	int fh_type,
	38	int (acceptable)(void context,
	39	struct dentry *dentry),
	40	void *context)
	41	{
b44b84d7	42	__be32 fh = (__force __be32 )p;
35dcc52e	43	struct gfs2_inum_host inum, parent;
b3b94faa	44
b3b94faa DT	45	memset(&parent, 0, sizeof(struct gfs2_inum));
b3b94faa DT	46
a7d2b2bd	47	switch (fh_len) {
5acd3967	48	case GFS2_LARGE_FH_SIZE:
3ebf4490	49	case GFS2_OLD_FH_SIZE:
cd915493	50	parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
b3b94faa	51	parent.no_formal_ino \|= be32_to_cpu(fh[5]);
cd915493	52	parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
b3b94faa	53	parent.no_addr \|= be32_to_cpu(fh[7]);
5acd3967	54	case GFS2_SMALL_FH_SIZE:
35dcc52e WC	55	inum.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
	56	inum.no_formal_ino \|= be32_to_cpu(fh[1]);
	57	inum.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
	58	inum.no_addr \|= be32_to_cpu(fh[3]);
b3b94faa DT	59	break;
	60	default:
	61	return NULL;
	62	}
	63
35dcc52e	64	return gfs2_export_ops.find_exported_dentry(sb, &inum, &parent,
b3b94faa DT	65	acceptable, context);
	66	}
	67
b44b84d7	68	static int gfs2_encode_fh(struct dentry dentry, __u32 p, int *len,
b3b94faa DT	69	int connectable)
b3b94faa DT	70	{
b44b84d7	71	__be32 fh = (__force __be32 )p;
b3b94faa	72	struct inode *inode = dentry->d_inode;
c9fd4307	73	struct super_block *sb = inode->i_sb;
feaa7bba	74	struct gfs2_inode *ip = GFS2_I(inode);
b3b94faa	75
5acd3967 SW	76	if (*len < GFS2_SMALL_FH_SIZE \|\|
5acd3967 SW	77	(connectable && *len < GFS2_LARGE_FH_SIZE))
b3b94faa DT	78	return 255;
b3b94faa DT	79
dbb7cae2 SW	80	fh[0] = cpu_to_be32(ip->i_no_formal_ino >> 32);
	81	fh[1] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
	82	fh[2] = cpu_to_be32(ip->i_no_addr >> 32);
	83	fh[3] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
5acd3967	84	*len = GFS2_SMALL_FH_SIZE;
b3b94faa	85
c9fd4307	86	if (!connectable \|\| inode == sb->s_root->d_inode)
b3b94faa DT	87	return *len;
	88
	89	spin_lock(&dentry->d_lock);
	90	inode = dentry->d_parent->d_inode;
feaa7bba SW	91	ip = GFS2_I(inode);
feaa7bba SW	92	igrab(inode);
b3b94faa DT	93	spin_unlock(&dentry->d_lock);
b3b94faa DT	94
dbb7cae2 SW	95	fh[4] = cpu_to_be32(ip->i_no_formal_ino >> 32);
	96	fh[5] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
	97	fh[6] = cpu_to_be32(ip->i_no_addr >> 32);
	98	fh[7] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
5acd3967	99	*len = GFS2_LARGE_FH_SIZE;
b3b94faa	100
feaa7bba	101	iput(inode);
b3b94faa DT	102
	103	return *len;
	104	}
	105
	106	struct get_name_filldir {
629a21e7	107	struct gfs2_inum_host inum;
b3b94faa DT	108	char *name;
	109	};
	110
3699e3a4 SW	111	static int get_name_filldir(void opaque, const char name, int length,
3699e3a4 SW	112	loff_t offset, u64 inum, unsigned int type)
b3b94faa	113	{
3699e3a4	114	struct get_name_filldir *gnfd = opaque;
b3b94faa	115
3699e3a4	116	if (inum != gnfd->inum.no_addr)
b3b94faa DT	117	return 0;
	118
	119	memcpy(gnfd->name, name, length);
	120	gnfd->name[length] = 0;
	121
	122	return 1;
	123	}
	124
	125	static int gfs2_get_name(struct dentry parent, char name,
	126	struct dentry *child)
	127	{
	128	struct inode *dir = parent->d_inode;
	129	struct inode *inode = child->d_inode;
	130	struct gfs2_inode dip, ip;
	131	struct get_name_filldir gnfd;
	132	struct gfs2_holder gh;
cd915493	133	u64 offset = 0;
b3b94faa DT	134	int error;
	135
	136	if (!dir)
	137	return -EINVAL;
	138
b3b94faa DT	139	if (!S_ISDIR(dir->i_mode) \|\| !inode)
	140	return -EINVAL;
	141
feaa7bba SW	142	dip = GFS2_I(dir);
feaa7bba SW	143	ip = GFS2_I(inode);
b3b94faa DT	144
b3b94faa DT	145	*name = 0;
dbb7cae2 SW	146	gnfd.inum.no_addr = ip->i_no_addr;
dbb7cae2 SW	147	gnfd.inum.no_formal_ino = ip->i_no_formal_ino;
b3b94faa DT	148	gnfd.name = name;
	149
	150	error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
	151	if (error)
	152	return error;
	153
71b86f56	154	error = gfs2_dir_read(dir, &offset, &gnfd, get_name_filldir);
b3b94faa DT	155
	156	gfs2_glock_dq_uninit(&gh);
	157
	158	if (!error && !*name)
	159	error = -ENOENT;
	160
	161	return error;
	162	}
	163
	164	static struct dentry gfs2_get_parent(struct dentry child)
	165	{
71b86f56	166	struct qstr dotdot;
b3b94faa DT	167	struct inode *inode;
b3b94faa DT	168	struct dentry *dentry;
b3b94faa	169
71b86f56	170	gfs2_str2qstr(&dotdot, "..");
c752666c SW	171	inode = gfs2_lookupi(child->d_inode, &dotdot, 1, NULL);
	172
	173	if (!inode)
	174	return ERR_PTR(-ENOENT);
7b625361 SW	175	/*
	176	* In case of an error, @inode carries the error value, and we
	177	* have to return that as a(n invalid) pointer to dentry.
	178	*/
c752666c SW	179	if (IS_ERR(inode))
c752666c SW	180	return ERR_PTR(PTR_ERR(inode));
b3b94faa	181
b3b94faa DT	182	dentry = d_alloc_anon(inode);
	183	if (!dentry) {
	184	iput(inode);
	185	return ERR_PTR(-ENOMEM);
	186	}
	187
70831465	188	dentry->d_op = &gfs2_dops;
b3b94faa DT	189	return dentry;
	190	}
	191
2eb168ca	192	static struct dentry gfs2_get_dentry(struct super_block sb, void *inum_obj)
b3b94faa	193	{
5c676f6d	194	struct gfs2_sbd *sdp = sb->s_fs_info;
35dcc52e	195	struct gfs2_inum_host *inum = inum_obj;
b3b94faa DT	196	struct gfs2_holder i_gh, ri_gh, rgd_gh;
b3b94faa DT	197	struct gfs2_rgrpd *rgd;
b3b94faa DT	198	struct inode *inode;
	199	struct dentry *dentry;
	200	int error;
	201
b3b94faa DT	202	/* System files? */
b3b94faa DT	203
dbb7cae2	204	inode = gfs2_ilookup(sb, inum->no_addr);
b3b94faa	205	if (inode) {
dbb7cae2	206	if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
b3b94faa DT	207	iput(inode);
	208	return ERR_PTR(-ESTALE);
	209	}
	210	goto out_inode;
	211	}
	212
feaa7bba	213	error = gfs2_glock_nq_num(sdp, inum->no_addr, &gfs2_inode_glops,
1c0f4872	214	LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
b3b94faa DT	215	if (error)
	216	return ERR_PTR(error);
	217
b3b94faa DT	218	error = gfs2_rindex_hold(sdp, &ri_gh);
	219	if (error)
	220	goto fail;
	221
	222	error = -EINVAL;
	223	rgd = gfs2_blk2rgrpd(sdp, inum->no_addr);
	224	if (!rgd)
	225	goto fail_rindex;
	226
	227	error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
	228	if (error)
	229	goto fail_rindex;
	230
	231	error = -ESTALE;
	232	if (gfs2_get_block_type(rgd, inum->no_addr) != GFS2_BLKST_DINODE)
	233	goto fail_rgd;
	234
	235	gfs2_glock_dq_uninit(&rgd_gh);
	236	gfs2_glock_dq_uninit(&ri_gh);
	237
35dcc52e	238	inode = gfs2_inode_lookup(sb, DT_UNKNOWN,
bb9bcf06	239	inum->no_addr,
7a9f53b3	240	0, 0);
feaa7bba SW	241	if (!inode)
	242	goto fail;
	243	if (IS_ERR(inode)) {
	244	error = PTR_ERR(inode);
b3b94faa	245	goto fail;
feaa7bba	246	}
b3b94faa	247
feaa7bba	248	error = gfs2_inode_refresh(GFS2_I(inode));
b3b94faa	249	if (error) {
feaa7bba	250	iput(inode);
b3b94faa DT	251	goto fail;
b3b94faa DT	252	}
35dcc52e WC	253
	254	/* Pick up the works we bypass in gfs2_inode_lookup */
	255	if (inode->i_state & I_NEW)
	256	gfs2_set_iop(inode);
	257
dbb7cae2 SW	258	if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
	259	iput(inode);
	260	goto fail;
	261	}
b3b94faa	262
b3b94faa	263	error = -EIO;
feaa7bba SW	264	if (GFS2_I(inode)->i_di.di_flags & GFS2_DIF_SYSTEM) {
feaa7bba SW	265	iput(inode);
b3b94faa DT	266	goto fail;
	267	}
	268
	269	gfs2_glock_dq_uninit(&i_gh);
	270
feaa7bba	271	out_inode:
b3b94faa DT	272	dentry = d_alloc_anon(inode);
	273	if (!dentry) {
	274	iput(inode);
	275	return ERR_PTR(-ENOMEM);
	276	}
	277
70831465	278	dentry->d_op = &gfs2_dops;
b3b94faa DT	279	return dentry;
b3b94faa DT	280
feaa7bba	281	fail_rgd:
b3b94faa DT	282	gfs2_glock_dq_uninit(&rgd_gh);
b3b94faa DT	283
feaa7bba	284	fail_rindex:
b3b94faa DT	285	gfs2_glock_dq_uninit(&ri_gh);
b3b94faa DT	286
feaa7bba	287	fail:
b3b94faa DT	288	gfs2_glock_dq_uninit(&i_gh);
	289	return ERR_PTR(error);
	290	}
	291
	292	struct export_operations gfs2_export_ops = {
	293	.decode_fh = gfs2_decode_fh,
	294	.encode_fh = gfs2_encode_fh,
	295	.get_name = gfs2_get_name,
	296	.get_parent = gfs2_get_parent,
	297	.get_dentry = gfs2_get_dentry,
	298	};
	299