xref: /freebsd-src/sys/contrib/openzfs/module/os/linux/zfs/zpl_export.c (revision 16d6b3b3da62aa5baaf3c66c8d4e6f8c8f70aeb7)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright (c) 2011 Gunnar Beutner
23  * Copyright (c) 2012 Cyril Plisko. All rights reserved.
24  */
25 
26 
27 #include <sys/zfs_znode.h>
28 #include <sys/zfs_vnops.h>
29 #include <sys/zfs_ctldir.h>
30 #include <sys/zpl.h>
31 
32 
33 static int
34 #ifdef HAVE_ENCODE_FH_WITH_INODE
35 zpl_encode_fh(struct inode *ip, __u32 *fh, int *max_len, struct inode *parent)
36 {
37 #else
38 zpl_encode_fh(struct dentry *dentry, __u32 *fh, int *max_len, int connectable)
39 {
40 	/* CSTYLED */
41 	struct inode *ip = dentry->d_inode;
42 #endif /* HAVE_ENCODE_FH_WITH_INODE */
43 	fstrans_cookie_t cookie;
44 	fid_t *fid = (fid_t *)fh;
45 	int len_bytes, rc;
46 
47 	len_bytes = *max_len * sizeof (__u32);
48 
49 	if (len_bytes < offsetof(fid_t, fid_data))
50 		return (255);
51 
52 	fid->fid_len = len_bytes - offsetof(fid_t, fid_data);
53 	cookie = spl_fstrans_mark();
54 
55 	if (zfsctl_is_node(ip))
56 		rc = zfsctl_fid(ip, fid);
57 	else
58 		rc = zfs_fid(ip, fid);
59 
60 	spl_fstrans_unmark(cookie);
61 	len_bytes = offsetof(fid_t, fid_data) + fid->fid_len;
62 	*max_len = roundup(len_bytes, sizeof (__u32)) / sizeof (__u32);
63 
64 	return (rc == 0 ? FILEID_INO32_GEN : 255);
65 }
66 
67 static struct dentry *
68 zpl_fh_to_dentry(struct super_block *sb, struct fid *fh,
69     int fh_len, int fh_type)
70 {
71 	fid_t *fid = (fid_t *)fh;
72 	fstrans_cookie_t cookie;
73 	struct inode *ip;
74 	int len_bytes, rc;
75 
76 	len_bytes = fh_len * sizeof (__u32);
77 
78 	if (fh_type != FILEID_INO32_GEN ||
79 	    len_bytes < offsetof(fid_t, fid_data) ||
80 	    len_bytes < offsetof(fid_t, fid_data) + fid->fid_len)
81 		return (ERR_PTR(-EINVAL));
82 
83 	cookie = spl_fstrans_mark();
84 	rc = zfs_vget(sb, &ip, fid);
85 	spl_fstrans_unmark(cookie);
86 
87 	if (rc) {
88 		/*
89 		 * If we see ENOENT it might mean that an NFSv4 * client
90 		 * is using a cached inode value in a file handle and
91 		 * that the sought after file has had its inode changed
92 		 * by a third party.  So change the error to ESTALE
93 		 * which will trigger a full lookup by the client and
94 		 * will find the new filename/inode pair if it still
95 		 * exists.
96 		 */
97 		if (rc == ENOENT)
98 			rc = ESTALE;
99 
100 		return (ERR_PTR(-rc));
101 	}
102 
103 	ASSERT((ip != NULL) && !IS_ERR(ip));
104 
105 	return (d_obtain_alias(ip));
106 }
107 
108 static struct dentry *
109 zpl_get_parent(struct dentry *child)
110 {
111 	cred_t *cr = CRED();
112 	fstrans_cookie_t cookie;
113 	znode_t *zp;
114 	int error;
115 
116 	crhold(cr);
117 	cookie = spl_fstrans_mark();
118 	error = -zfs_lookup(ITOZ(child->d_inode), "..", &zp, 0, cr, NULL, NULL);
119 	spl_fstrans_unmark(cookie);
120 	crfree(cr);
121 	ASSERT3S(error, <=, 0);
122 
123 	if (error)
124 		return (ERR_PTR(error));
125 
126 	return (d_obtain_alias(ZTOI(zp)));
127 }
128 
129 static int
130 zpl_commit_metadata(struct inode *inode)
131 {
132 	cred_t *cr = CRED();
133 	fstrans_cookie_t cookie;
134 	int error;
135 
136 	if (zfsctl_is_node(inode))
137 		return (0);
138 
139 	crhold(cr);
140 	cookie = spl_fstrans_mark();
141 	error = -zfs_fsync(ITOZ(inode), 0, cr);
142 	spl_fstrans_unmark(cookie);
143 	crfree(cr);
144 	ASSERT3S(error, <=, 0);
145 
146 	return (error);
147 }
148 
149 const struct export_operations zpl_export_operations = {
150 	.encode_fh		= zpl_encode_fh,
151 	.fh_to_dentry		= zpl_fh_to_dentry,
152 	.get_parent		= zpl_get_parent,
153 	.commit_metadata	= zpl_commit_metadata,
154 };
155