zfeature_common.c revision 239774 
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 */
25
26#ifdef _KERNEL
27#include <sys/systm.h>
28#else
29#include <errno.h>
30#include <string.h>
31#endif
32#include <sys/debug.h>
33#include <sys/fs/zfs.h>
34#include <sys/types.h>
35#include "zfeature_common.h"
36
37/*
38 * Set to disable all feature checks while opening pools, allowing pools with
39 * unsupported features to be opened. Set for testing only.
40 */
41boolean_t zfeature_checks_disable = B_FALSE;
42
43zfeature_info_t spa_feature_table[SPA_FEATURES];
44
45/*
46 * Valid characters for feature guids. This list is mainly for aesthetic
47 * purposes and could be expanded in the future. There are different allowed
48 * characters in the guids reverse dns portion (before the colon) and its
49 * short name (after the colon).
50 */
51static int
52valid_char(char c, boolean_t after_colon)
53{
54	return ((c >= 'a' && c <= 'z') ||
55	    (c >= '0' && c <= '9') ||
56	    c == (after_colon ? '_' : '.'));
57}
58
59/*
60 * Every feature guid must contain exactly one colon which separates a reverse
61 * dns organization name from the feature's "short" name (e.g.
62 * "com.company:feature_name").
63 */
64boolean_t
65zfeature_is_valid_guid(const char *name)
66{
67	int i;
68	boolean_t has_colon = B_FALSE;
69
70	i = 0;
71	while (name[i] != '\0') {
72		char c = name[i++];
73		if (c == ':') {
74			if (has_colon)
75				return (B_FALSE);
76			has_colon = B_TRUE;
77			continue;
78		}
79		if (!valid_char(c, has_colon))
80			return (B_FALSE);
81	}
82
83	return (has_colon);
84}
85
86boolean_t
87zfeature_is_supported(const char *guid)
88{
89	if (zfeature_checks_disable)
90		return (B_TRUE);
91
92	return (0 == zfeature_lookup_guid(guid, NULL));
93}
94
95int
96zfeature_lookup_guid(const char *guid, zfeature_info_t **res)
97{
98	for (int i = 0; i < SPA_FEATURES; i++) {
99		zfeature_info_t *feature = &spa_feature_table[i];
100		if (strcmp(guid, feature->fi_guid) == 0) {
101			if (res != NULL)
102				*res = feature;
103			return (0);
104		}
105	}
106
107	return (ENOENT);
108}
109
110int
111zfeature_lookup_name(const char *name, zfeature_info_t **res)
112{
113	for (int i = 0; i < SPA_FEATURES; i++) {
114		zfeature_info_t *feature = &spa_feature_table[i];
115		if (strcmp(name, feature->fi_uname) == 0) {
116			if (res != NULL)
117				*res = feature;
118			return (0);
119		}
120	}
121
122	return (ENOENT);
123}
124
125static void
126zfeature_register(int fid, const char *guid, const char *name, const char *desc,
127    boolean_t readonly, boolean_t mos, zfeature_info_t **deps)
128{
129	zfeature_info_t *feature = &spa_feature_table[fid];
130	static zfeature_info_t *nodeps[] = { NULL };
131
132	ASSERT(name != NULL);
133	ASSERT(desc != NULL);
134	ASSERT(!readonly || !mos);
135	ASSERT3U(fid, <, SPA_FEATURES);
136	ASSERT(zfeature_is_valid_guid(guid));
137
138	if (deps == NULL)
139		deps = nodeps;
140
141	feature->fi_guid = guid;
142	feature->fi_uname = name;
143	feature->fi_desc = desc;
144	feature->fi_can_readonly = readonly;
145	feature->fi_mos = mos;
146	feature->fi_depends = deps;
147}
148
149void
150zpool_feature_init(void)
151{
152	zfeature_register(SPA_FEATURE_ASYNC_DESTROY,
153	    "com.delphix:async_destroy", "async_destroy",
154	    "Destroy filesystems asynchronously.", B_TRUE, B_FALSE, NULL);
155	zfeature_register(SPA_FEATURE_EMPTY_BPOBJ,
156	    "com.delphix:empty_bpobj", "empty_bpobj",
157	    "Snapshots use less space.", B_TRUE, B_FALSE, NULL);
158}
159