Root/fs/ocfs2/export.c

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

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