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/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         for (spa_feature_t i = 0; i < SPA_FEATURES; i++) {
  96                 zfeature_info_t *feature = &spa_feature_table[i];
  97                 if (strcmp(guid, feature->fi_guid) == 0)
  98                         return (B_TRUE);
  99         }
 100         return (B_FALSE);
 101 }
 102 
 103 int
 104 zfeature_lookup_name(const char *name, spa_feature_t *res)
 105 {
 106         for (spa_feature_t i = 0; i < SPA_FEATURES; i++) {
 107                 zfeature_info_t *feature = &spa_feature_table[i];
 108                 if (strcmp(name, feature->fi_uname) == 0) {
 109                         if (res != NULL)
 110                                 *res = i;
 111                         return (0);
 112                 }
 113         }
 114 
 115         return (ENOENT);
 116 }
 117 
 118 static void
 119 zfeature_register(spa_feature_t fid, const char *guid, const char *name,
 120     const char *desc, boolean_t readonly, boolean_t mos,
 121     const spa_feature_t *deps)
 122 {
 123         zfeature_info_t *feature = &spa_feature_table[fid];
 124         static spa_feature_t nodeps[] = { SPA_FEATURE_NONE };
 125 
 126         ASSERT(name != NULL);
 127         ASSERT(desc != NULL);
 128         ASSERT(!readonly || !mos);
 129         ASSERT3U(fid, <, SPA_FEATURES);
 130         ASSERT(zfeature_is_valid_guid(guid));
 131 
 132         if (deps == NULL)
 133                 deps = nodeps;
 134 
 135         feature->fi_feature = fid;
 136         feature->fi_guid = guid;
 137         feature->fi_uname = name;
 138         feature->fi_desc = desc;
 139         feature->fi_can_readonly = readonly;
 140         feature->fi_mos = mos;
 141         feature->fi_depends = deps;
 142 }
 143 
 144 void
 145 zpool_feature_init(void)
 146 {
 147         zfeature_register(SPA_FEATURE_ASYNC_DESTROY,
 148             "com.delphix:async_destroy", "async_destroy",
 149             "Destroy filesystems asynchronously.", B_TRUE, B_FALSE, NULL);
 150         zfeature_register(SPA_FEATURE_EMPTY_BPOBJ,
 151             "com.delphix:empty_bpobj", "empty_bpobj",
 152             "Snapshots use less space.", B_TRUE, B_FALSE, NULL);
 153         zfeature_register(SPA_FEATURE_LZ4_COMPRESS,
 154             "org.illumos:lz4_compress", "lz4_compress",
 155             "LZ4 compression algorithm support.", B_FALSE, B_FALSE, NULL);
 156         zfeature_register(SPA_FEATURE_MULTI_VDEV_CRASH_DUMP,
 157             "com.joyent:multi_vdev_crash_dump", "multi_vdev_crash_dump",
 158             "Crash dumps to multiple vdev pools.", B_FALSE, B_FALSE, NULL);
 159         zfeature_register(SPA_FEATURE_SPACEMAP_HISTOGRAM,
 160             "com.delphix:spacemap_histogram", "spacemap_histogram",
 161             "Spacemaps maintain space histograms.", B_TRUE, B_FALSE, NULL);
 162         zfeature_register(SPA_FEATURE_EXTENSIBLE_DATASET,
 163             "com.delphix:extensible_dataset", "extensible_dataset",
 164             "Enhanced dataset functionality, used by other features.",
 165             B_FALSE, B_FALSE, NULL);
 166 }