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