zfeature_common.c revision 262093 
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) 2013 by Delphix. All rights reserved.
24 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
25 * Copyright (c) 2013, Joyent, Inc. All rights reserved.
26 */
27
28#ifdef _KERNEL
29#include <sys/systm.h>
30#else
31#include <errno.h>
32#include <string.h>
33#endif
34#include <sys/debug.h>
35#include <sys/fs/zfs.h>
36#include <sys/types.h>
37#include "zfeature_common.h"
38
39/*
40 * Set to disable all feature checks while opening pools, allowing pools with
41 * unsupported features to be opened. Set for testing only.
42 */
43boolean_t zfeature_checks_disable = B_FALSE;
44
45zfeature_info_t spa_feature_table[SPA_FEATURES];
46
47/*
48 * Valid characters for feature guids. This list is mainly for aesthetic
49 * purposes and could be expanded in the future. There are different allowed
50 * characters in the guids reverse dns portion (before the colon) and its
51 * short name (after the colon).
52 */
53static int
54valid_char(char c, boolean_t after_colon)
55{
56	return ((c >= 'a' && c <= 'z') ||
57	    (c >= '0' && c <= '9') ||
58	    c == (after_colon ? '_' : '.'));
59}
60
61/*
62 * Every feature guid must contain exactly one colon which separates a reverse
63 * dns organization name from the feature's "short" name (e.g.
64 * "com.company:feature_name").
65 */
66boolean_t
67zfeature_is_valid_guid(const char *name)
68{
69	int i;
70	boolean_t has_colon = B_FALSE;
71
72	i = 0;
73	while (name[i] != '\0') {
74		char c = name[i++];
75		if (c == ':') {
76			if (has_colon)
77				return (B_FALSE);
78			has_colon = B_TRUE;
79			continue;
80		}
81		if (!valid_char(c, has_colon))
82			return (B_FALSE);
83	}
84
85	return (has_colon);
86}
87
88boolean_t
89zfeature_is_supported(const char *guid)
90{
91	if (zfeature_checks_disable)
92		return (B_TRUE);
93
94	return (0 == zfeature_lookup_guid(guid, NULL));
95}
96
97int
98zfeature_lookup_guid(const char *guid, zfeature_info_t **res)
99{
100	for (int i = 0; i < SPA_FEATURES; i++) {
101		zfeature_info_t *feature = &spa_feature_table[i];
102		if (strcmp(guid, feature->fi_guid) == 0) {
103			if (res != NULL)
104				*res = feature;
105			return (0);
106		}
107	}
108
109	return (ENOENT);
110}
111
112int
113zfeature_lookup_name(const char *name, zfeature_info_t **res)
114{
115	for (int i = 0; i < SPA_FEATURES; i++) {
116		zfeature_info_t *feature = &spa_feature_table[i];
117		if (strcmp(name, feature->fi_uname) == 0) {
118			if (res != NULL)
119				*res = feature;
120			return (0);
121		}
122	}
123
124	return (ENOENT);
125}
126
127static void
128zfeature_register(int fid, const char *guid, const char *name, const char *desc,
129    boolean_t readonly, boolean_t mos, zfeature_info_t **deps)
130{
131	zfeature_info_t *feature = &spa_feature_table[fid];
132	static zfeature_info_t *nodeps[] = { NULL };
133
134	ASSERT(name != NULL);
135	ASSERT(desc != NULL);
136	ASSERT(!readonly || !mos);
137	ASSERT3U(fid, <, SPA_FEATURES);
138	ASSERT(zfeature_is_valid_guid(guid));
139
140	if (deps == NULL)
141		deps = nodeps;
142
143	feature->fi_guid = guid;
144	feature->fi_uname = name;
145	feature->fi_desc = desc;
146	feature->fi_can_readonly = readonly;
147	feature->fi_mos = mos;
148	feature->fi_depends = deps;
149}
150
151void
152zpool_feature_init(void)
153{
154	zfeature_register(SPA_FEATURE_ASYNC_DESTROY,
155	    "com.delphix:async_destroy", "async_destroy",
156	    "Destroy filesystems asynchronously.", B_TRUE, B_FALSE, NULL);
157	zfeature_register(SPA_FEATURE_EMPTY_BPOBJ,
158	    "com.delphix:empty_bpobj", "empty_bpobj",
159	    "Snapshots use less space.", B_TRUE, B_FALSE, NULL);
160	zfeature_register(SPA_FEATURE_LZ4_COMPRESS,
161	    "org.illumos:lz4_compress", "lz4_compress",
162	    "LZ4 compression algorithm support.", B_FALSE, B_FALSE, NULL);
163	zfeature_register(SPA_FEATURE_MULTI_VDEV_CRASH_DUMP,
164	    "com.joyent:multi_vdev_crash_dump", "multi_vdev_crash_dump",
165	    "Crash dumps to multiple vdev pools.", B_FALSE, B_FALSE, NULL);
166	zfeature_register(SPA_FEATURE_SPACEMAP_HISTOGRAM,
167	    "com.delphix:spacemap_histogram", "spacemap_histogram",
168	    "Spacemaps maintain space histograms.", B_TRUE, B_FALSE, NULL);
169}
170