1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * export.c
4 *
5 * Functions to facilitate NFS exporting
6 *
7 * Copyright (C) 2002, 2005 Oracle.  All rights reserved.
8 */
9
10#include <linux/fs.h>
11#include <linux/types.h>
12
13#include <cluster/masklog.h>
14
15#include "ocfs2.h"
16
17#include "alloc.h"
18#include "dir.h"
19#include "dlmglue.h"
20#include "dcache.h"
21#include "export.h"
22#include "inode.h"
23
24#include "buffer_head_io.h"
25#include "suballoc.h"
26#include "ocfs2_trace.h"
27
28struct ocfs2_inode_handle
29{
30	u64 ih_blkno;
31	u32 ih_generation;
32};
33
34static struct dentry *ocfs2_get_dentry(struct super_block *sb,
35		struct ocfs2_inode_handle *handle)
36{
37	struct inode *inode;
38	struct ocfs2_super *osb = OCFS2_SB(sb);
39	u64 blkno = handle->ih_blkno;
40	int status, set;
41	struct dentry *result;
42
43	trace_ocfs2_get_dentry_begin(sb, handle, (unsigned long long)blkno);
44
45	if (blkno == 0) {
46		result = ERR_PTR(-ESTALE);
47		goto bail;
48	}
49
50	inode = ocfs2_ilookup(sb, blkno);
51	/*
52	 * If the inode exists in memory, we only need to check it's
53	 * generation number
54	 */
55	if (inode)
56		goto check_gen;
57
58	/*
59	 * This will synchronize us against ocfs2_delete_inode() on
60	 * all nodes
61	 */
62	status = ocfs2_nfs_sync_lock(osb, 1);
63	if (status < 0) {
64		mlog(ML_ERROR, "getting nfs sync lock(EX) failed %d\n", status);
65		goto check_err;
66	}
67
68	status = ocfs2_test_inode_bit(osb, blkno, &set);
69	if (status < 0) {
70		if (status == -EINVAL) {
71			/*
72			 * The blkno NFS gave us doesn't even show up
73			 * as an inode, we return -ESTALE to be
74			 * nice
75			 */
76			status = -ESTALE;
77		} else
78			mlog(ML_ERROR, "test inode bit failed %d\n", status);
79		goto unlock_nfs_sync;
80	}
81
82	trace_ocfs2_get_dentry_test_bit(status, set);
83	/* If the inode allocator bit is clear, this inode must be stale */
84	if (!set) {
85		status = -ESTALE;
86		goto unlock_nfs_sync;
87	}
88
89	inode = ocfs2_iget(osb, blkno, 0, 0);
90
91unlock_nfs_sync:
92	ocfs2_nfs_sync_unlock(osb, 1);
93
94check_err:
95	if (status < 0) {
96		if (status == -ESTALE) {
97			trace_ocfs2_get_dentry_stale((unsigned long long)blkno,
98						     handle->ih_generation);
99		}
100		result = ERR_PTR(status);
101		goto bail;
102	}
103
104	if (IS_ERR(inode)) {
105		mlog_errno(PTR_ERR(inode));
106		result = ERR_CAST(inode);
107		goto bail;
108	}
109
110check_gen:
111	if (handle->ih_generation != inode->i_generation) {
112		trace_ocfs2_get_dentry_generation((unsigned long long)blkno,
113						  handle->ih_generation,
114						  inode->i_generation);
115		iput(inode);
116		result = ERR_PTR(-ESTALE);
117		goto bail;
118	}
119
120	result = d_obtain_alias(inode);
121	if (IS_ERR(result))
122		mlog_errno(PTR_ERR(result));
123
124bail:
125	trace_ocfs2_get_dentry_end(result);
126	return result;
127}
128
129static struct dentry *ocfs2_get_parent(struct dentry *child)
130{
131	int status;
132	u64 blkno;
133	struct dentry *parent;
134	struct inode *dir = d_inode(child);
135	int set;
136
137	trace_ocfs2_get_parent(child, child->d_name.len, child->d_name.name,
138			       (unsigned long long)OCFS2_I(dir)->ip_blkno);
139
140	status = ocfs2_nfs_sync_lock(OCFS2_SB(dir->i_sb), 1);
141	if (status < 0) {
142		mlog(ML_ERROR, "getting nfs sync lock(EX) failed %d\n", status);
143		parent = ERR_PTR(status);
144		goto bail;
145	}
146
147	status = ocfs2_inode_lock(dir, NULL, 0);
148	if (status < 0) {
149		if (status != -ENOENT)
150			mlog_errno(status);
151		parent = ERR_PTR(status);
152		goto unlock_nfs_sync;
153	}
154
155	status = ocfs2_lookup_ino_from_name(dir, "..", 2, &blkno);
156	if (status < 0) {
157		parent = ERR_PTR(-ENOENT);
158		goto bail_unlock;
159	}
160
161	status = ocfs2_test_inode_bit(OCFS2_SB(dir->i_sb), blkno, &set);
162	if (status < 0) {
163		if (status == -EINVAL) {
164			status = -ESTALE;
165		} else
166			mlog(ML_ERROR, "test inode bit failed %d\n", status);
167		parent = ERR_PTR(status);
168		goto bail_unlock;
169	}
170
171	trace_ocfs2_get_dentry_test_bit(status, set);
172	if (!set) {
173		status = -ESTALE;
174		parent = ERR_PTR(status);
175		goto bail_unlock;
176	}
177
178	parent = d_obtain_alias(ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0, 0));
179
180bail_unlock:
181	ocfs2_inode_unlock(dir, 0);
182
183unlock_nfs_sync:
184	ocfs2_nfs_sync_unlock(OCFS2_SB(dir->i_sb), 1);
185
186bail:
187	trace_ocfs2_get_parent_end(parent);
188
189	return parent;
190}
191
192static int ocfs2_encode_fh(struct inode *inode, u32 *fh_in, int *max_len,
193			   struct inode *parent)
194{
195	int len = *max_len;
196	int type = 1;
197	u64 blkno;
198	u32 generation;
199	__le32 *fh = (__force __le32 *) fh_in;
200
201#ifdef TRACE_HOOKS_ARE_NOT_BRAINDEAD_IN_YOUR_OPINION
202#error "You go ahead and fix that mess, then.  Somehow"
203	trace_ocfs2_encode_fh_begin(dentry, dentry->d_name.len,
204				    dentry->d_name.name,
205				    fh, len, connectable);
206#endif
207
208	if (parent && (len < 6)) {
209		*max_len = 6;
210		type = FILEID_INVALID;
211		goto bail;
212	} else if (len < 3) {
213		*max_len = 3;
214		type = FILEID_INVALID;
215		goto bail;
216	}
217
218	blkno = OCFS2_I(inode)->ip_blkno;
219	generation = inode->i_generation;
220
221	trace_ocfs2_encode_fh_self((unsigned long long)blkno, generation);
222
223	len = 3;
224	fh[0] = cpu_to_le32((u32)(blkno >> 32));
225	fh[1] = cpu_to_le32((u32)(blkno & 0xffffffff));
226	fh[2] = cpu_to_le32(generation);
227
228	if (parent) {
229		blkno = OCFS2_I(parent)->ip_blkno;
230		generation = parent->i_generation;
231
232		fh[3] = cpu_to_le32((u32)(blkno >> 32));
233		fh[4] = cpu_to_le32((u32)(blkno & 0xffffffff));
234		fh[5] = cpu_to_le32(generation);
235
236		len = 6;
237		type = 2;
238
239		trace_ocfs2_encode_fh_parent((unsigned long long)blkno,
240					     generation);
241	}
242
243	*max_len = len;
244
245bail:
246	trace_ocfs2_encode_fh_type(type);
247	return type;
248}
249
250static struct dentry *ocfs2_fh_to_dentry(struct super_block *sb,
251		struct fid *fid, int fh_len, int fh_type)
252{
253	struct ocfs2_inode_handle handle;
254
255	if (fh_len < 3 || fh_type > 2)
256		return NULL;
257
258	handle.ih_blkno = (u64)le32_to_cpu(fid->raw[0]) << 32;
259	handle.ih_blkno |= (u64)le32_to_cpu(fid->raw[1]);
260	handle.ih_generation = le32_to_cpu(fid->raw[2]);
261	return ocfs2_get_dentry(sb, &handle);
262}
263
264static struct dentry *ocfs2_fh_to_parent(struct super_block *sb,
265		struct fid *fid, int fh_len, int fh_type)
266{
267	struct ocfs2_inode_handle parent;
268
269	if (fh_type != 2 || fh_len < 6)
270		return NULL;
271
272	parent.ih_blkno = (u64)le32_to_cpu(fid->raw[3]) << 32;
273	parent.ih_blkno |= (u64)le32_to_cpu(fid->raw[4]);
274	parent.ih_generation = le32_to_cpu(fid->raw[5]);
275	return ocfs2_get_dentry(sb, &parent);
276}
277
278const struct export_operations ocfs2_export_ops = {
279	.encode_fh	= ocfs2_encode_fh,
280	.fh_to_dentry	= ocfs2_fh_to_dentry,
281	.fh_to_parent	= ocfs2_fh_to_parent,
282	.get_parent	= ocfs2_get_parent,
283	.flags		= EXPORT_OP_ASYNC_LOCK,
284};
285