zfeature_common.c revision 247309 
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/*
23 * Copyright (c) 2012 by Delphix. All rights reserved.
24 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
25 */
26
27#ifdef _KERNEL
28#include <sys/systm.h>
29#else
30#include <errno.h>
31#include <string.h>
32#endif
33#include <sys/debug.h>
34#include <sys/fs/zfs.h>
35#include <sys/types.h>
36#include "zfeature_common.h"
37
38/*
39 * Set to disable all feature checks while opening pools, allowing pools with
40 * unsupported features to be opened. Set for testing only.
41 */
42boolean_t zfeature_checks_disable = B_FALSE;
43
44zfeature_info_t spa_feature_table[SPA_FEATURES];
45
46/*
47 * Valid characters for feature guids. This list is mainly for aesthetic
48 * purposes and could be expanded in the future. There are different allowed
49 * characters in the guids reverse dns portion (before the colon) and its
50 * short name (after the colon).
51 */
52static int
53valid_char(char c, boolean_t after_colon)
54{
55	return ((c >= 'a' && c <= 'z') ||
56	    (c >= '0' && c <= '9') ||
57	    c == (after_colon ? '_' : '.'));
58}
59
60/*
61 * Every feature guid must contain exactly one colon which separates a reverse
62 * dns organization name from the feature's "short" name (e.g.
63 * "com.company:feature_name").
64 */
65boolean_t
66zfeature_is_valid_guid(const char *name)
67{
68	int i;
69	boolean_t has_colon = B_FALSE;
70
71	i = 0;
72	while (name[i] != '\0') {
73		char c = name[i++];
74		if (c == ':') {
75			if (has_colon)
76				return (B_FALSE);
77			has_colon = B_TRUE;
78			continue;
79		}
80		if (!valid_char(c, has_colon))
81			return (B_FALSE);
82	}
83
84	return (has_colon);
85}
86
87boolean_t
88zfeature_is_supported(const char *guid)
89{
90	if (zfeature_checks_disable)
91		return (B_TRUE);
92
93	return (0 == zfeature_lookup_guid(guid, NULL));
94}
95
96int
97zfeature_lookup_guid(const char *guid, zfeature_info_t **res)
98{
99	for (int i = 0; i < SPA_FEATURES; i++) {
100		zfeature_info_t *feature = &spa_feature_table[i];
101		if (strcmp(guid, feature->fi_guid) == 0) {
102			if (res != NULL)
103				*res = feature;
104			return (0);
105		}
106	}
107
108	return (ENOENT);
109}
110
111int
112zfeature_lookup_name(const char *name, zfeature_info_t **res)
113{
114	for (int i = 0; i < SPA_FEATURES; i++) {
115		zfeature_info_t *feature = &spa_feature_table[i];
116		if (strcmp(name, feature->fi_uname) == 0) {
117			if (res != NULL)
118				*res = feature;
119			return (0);
120		}
121	}
122
123	return (ENOENT);
124}
125
126static void
127zfeature_register(int fid, const char *guid, const char *name, const char *desc,
128    boolean_t readonly, boolean_t mos, zfeature_info_t **deps)
129{
130	zfeature_info_t *feature = &spa_feature_table[fid];
131	static zfeature_info_t *nodeps[] = { NULL };
132
133	ASSERT(name != NULL);
134	ASSERT(desc != NULL);
135	ASSERT(!readonly || !mos);
136	ASSERT3U(fid, <, SPA_FEATURES);
137	ASSERT(zfeature_is_valid_guid(guid));
138
139	if (deps == NULL)
140		deps = nodeps;
141
142	feature->fi_guid = guid;
143	feature->fi_uname = name;
144	feature->fi_desc = desc;
145	feature->fi_can_readonly = readonly;
146	feature->fi_mos = mos;
147	feature->fi_depends = deps;
148}
149
150void
151zpool_feature_init(void)
152{
153	zfeature_register(SPA_FEATURE_ASYNC_DESTROY,
154	    "com.delphix:async_destroy", "async_destroy",
155	    "Destroy filesystems asynchronously.", B_TRUE, B_FALSE, NULL);
156	zfeature_register(SPA_FEATURE_EMPTY_BPOBJ,
157	    "com.delphix:empty_bpobj", "empty_bpobj",
158	    "Snapshots use less space.", B_TRUE, B_FALSE, NULL);
159	zfeature_register(SPA_FEATURE_LZ4_COMPRESS,
160	    "org.illumos:lz4_compress", "lz4_compress",
161	    "LZ4 compression algorithm support.", B_FALSE, B_FALSE, NULL);
162}
163