1/* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * export.c
5 *
6 * Functions to facilitate NFS exporting
7 *
8 * Copyright (C) 2002, 2005 Oracle.  All rights reserved.
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public
12 * License as published by the Free Software Foundation; either
13 * version 2 of the License, or (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public
21 * License along with this program; if not, write to the
22 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
23 * Boston, MA 021110-1307, USA.
24 */
25
26#include <linux/fs.h>
27#include <linux/types.h>
28
29#define MLOG_MASK_PREFIX ML_EXPORT
30#include <cluster/masklog.h>
31
32#include "ocfs2.h"
33
34#include "dir.h"
35#include "dlmglue.h"
36#include "dcache.h"
37#include "export.h"
38#include "inode.h"
39
40#include "buffer_head_io.h"
41
42struct ocfs2_inode_handle
43{
44	u64 ih_blkno;
45	u32 ih_generation;
46};
47
48static struct dentry *ocfs2_get_dentry(struct super_block *sb, void *vobjp)
49{
50	struct ocfs2_inode_handle *handle = vobjp;
51	struct inode *inode;
52	struct dentry *result;
53
54	mlog_entry("(0x%p, 0x%p)\n", sb, handle);
55
56	if (handle->ih_blkno == 0) {
57		mlog_errno(-ESTALE);
58		return ERR_PTR(-ESTALE);
59	}
60
61	inode = ocfs2_iget(OCFS2_SB(sb), handle->ih_blkno, 0);
62
63	if (IS_ERR(inode))
64		return (void *)inode;
65
66	if (handle->ih_generation != inode->i_generation) {
67		iput(inode);
68		return ERR_PTR(-ESTALE);
69	}
70
71	result = d_alloc_anon(inode);
72
73	if (!result) {
74		iput(inode);
75		mlog_errno(-ENOMEM);
76		return ERR_PTR(-ENOMEM);
77	}
78	result->d_op = &ocfs2_dentry_ops;
79
80	mlog_exit_ptr(result);
81	return result;
82}
83
84static struct dentry *ocfs2_get_parent(struct dentry *child)
85{
86	int status;
87	u64 blkno;
88	struct dentry *parent;
89	struct inode *inode;
90	struct inode *dir = child->d_inode;
91	struct buffer_head *dirent_bh = NULL;
92	struct ocfs2_dir_entry *dirent;
93
94	mlog_entry("(0x%p, '%.*s')\n", child,
95		   child->d_name.len, child->d_name.name);
96
97	mlog(0, "find parent of directory %llu\n",
98	     (unsigned long long)OCFS2_I(dir)->ip_blkno);
99
100	status = ocfs2_meta_lock(dir, NULL, 0);
101	if (status < 0) {
102		if (status != -ENOENT)
103			mlog_errno(status);
104		parent = ERR_PTR(status);
105		goto bail;
106	}
107
108	status = ocfs2_find_files_on_disk("..", 2, &blkno, dir, &dirent_bh,
109					  &dirent);
110	if (status < 0) {
111		parent = ERR_PTR(-ENOENT);
112		goto bail_unlock;
113	}
114
115	inode = ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0);
116	if (IS_ERR(inode)) {
117		mlog(ML_ERROR, "Unable to create inode %llu\n",
118		     (unsigned long long)blkno);
119		parent = ERR_PTR(-EACCES);
120		goto bail_unlock;
121	}
122
123	parent = d_alloc_anon(inode);
124	if (!parent) {
125		iput(inode);
126		parent = ERR_PTR(-ENOMEM);
127	}
128
129	parent->d_op = &ocfs2_dentry_ops;
130
131bail_unlock:
132	ocfs2_meta_unlock(dir, 0);
133
134	if (dirent_bh)
135		brelse(dirent_bh);
136
137bail:
138	mlog_exit_ptr(parent);
139
140	return parent;
141}
142
143static int ocfs2_encode_fh(struct dentry *dentry, u32 *fh_in, int *max_len,
144			   int connectable)
145{
146	struct inode *inode = dentry->d_inode;
147	int len = *max_len;
148	int type = 1;
149	u64 blkno;
150	u32 generation;
151	__le32 *fh = (__force __le32 *) fh_in;
152
153	mlog_entry("(0x%p, '%.*s', 0x%p, %d, %d)\n", dentry,
154		   dentry->d_name.len, dentry->d_name.name,
155		   fh, len, connectable);
156
157	if (len < 3 || (connectable && len < 6)) {
158		mlog(ML_ERROR, "fh buffer is too small for encoding\n");
159		type = 255;
160		goto bail;
161	}
162
163	blkno = OCFS2_I(inode)->ip_blkno;
164	generation = inode->i_generation;
165
166	mlog(0, "Encoding fh: blkno: %llu, generation: %u\n",
167	     (unsigned long long)blkno, generation);
168
169	len = 3;
170	fh[0] = cpu_to_le32((u32)(blkno >> 32));
171	fh[1] = cpu_to_le32((u32)(blkno & 0xffffffff));
172	fh[2] = cpu_to_le32(generation);
173
174	if (connectable && !S_ISDIR(inode->i_mode)) {
175		struct inode *parent;
176
177		spin_lock(&dentry->d_lock);
178
179		parent = dentry->d_parent->d_inode;
180		blkno = OCFS2_I(parent)->ip_blkno;
181		generation = parent->i_generation;
182
183		fh[3] = cpu_to_le32((u32)(blkno >> 32));
184		fh[4] = cpu_to_le32((u32)(blkno & 0xffffffff));
185		fh[5] = cpu_to_le32(generation);
186
187		spin_unlock(&dentry->d_lock);
188
189		len = 6;
190		type = 2;
191
192		mlog(0, "Encoding parent: blkno: %llu, generation: %u\n",
193		     (unsigned long long)blkno, generation);
194	}
195
196	*max_len = len;
197
198bail:
199	mlog_exit(type);
200	return type;
201}
202
203static struct dentry *ocfs2_decode_fh(struct super_block *sb, u32 *fh_in,
204				      int fh_len, int fileid_type,
205				      int (*acceptable)(void *context,
206						        struct dentry *de),
207				      void *context)
208{
209	struct ocfs2_inode_handle handle, parent;
210	struct dentry *ret = NULL;
211	__le32 *fh = (__force __le32 *) fh_in;
212
213	mlog_entry("(0x%p, 0x%p, %d, %d, 0x%p, 0x%p)\n",
214		   sb, fh, fh_len, fileid_type, acceptable, context);
215
216	if (fh_len < 3 || fileid_type > 2)
217		goto bail;
218
219	if (fileid_type == 2) {
220		if (fh_len < 6)
221			goto bail;
222
223		parent.ih_blkno = (u64)le32_to_cpu(fh[3]) << 32;
224		parent.ih_blkno |= (u64)le32_to_cpu(fh[4]);
225		parent.ih_generation = le32_to_cpu(fh[5]);
226
227		mlog(0, "Decoding parent: blkno: %llu, generation: %u\n",
228		     (unsigned long long)parent.ih_blkno,
229		     parent.ih_generation);
230	}
231
232	handle.ih_blkno = (u64)le32_to_cpu(fh[0]) << 32;
233	handle.ih_blkno |= (u64)le32_to_cpu(fh[1]);
234	handle.ih_generation = le32_to_cpu(fh[2]);
235
236	mlog(0, "Encoding fh: blkno: %llu, generation: %u\n",
237	     (unsigned long long)handle.ih_blkno, handle.ih_generation);
238
239	ret = ocfs2_export_ops.find_exported_dentry(sb, &handle, &parent,
240						    acceptable, context);
241
242bail:
243	mlog_exit_ptr(ret);
244	return ret;
245}
246
247struct export_operations ocfs2_export_ops = {
248	.decode_fh	= ocfs2_decode_fh,
249	.encode_fh	= ocfs2_encode_fh,
250
251	.get_parent	= ocfs2_get_parent,
252	.get_dentry	= ocfs2_get_dentry,
253};
254