sys/cddl/contrib/opensolaris/common/zfs/zfeature_common.c

   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  * 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  */
  43 boolean_t zfeature_checks_disable = B_FALSE;
  44
  45 zfeature_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  */
  53 static int
  54 valid_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  */
  66 boolean_t
  67 zfeature_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
  88 boolean_t
  89 zfeature_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
  97 int
  98 zfeature_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
 112 int
 113 zfeature_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
 127 static void
 128 zfeature_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
 151 void
 152 zpool_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 }