module/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  */
  26
  27 #ifdef _KERNEL
  28 #include <sys/systm.h>
  29 #else
  30 #include <errno.h>
  31 #include <string.h>
  32 #endif
  33 #include <sys/debug.h>
  34 #include <sys/fs/zfs.h>
  35 #include <sys/inttypes.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         int i;
 101
 102         for (i = 0; i < SPA_FEATURES; i++) {
 103                 zfeature_info_t *feature = &spa_feature_table[i];
 104                 if (strcmp(guid, feature->fi_guid) == 0) {
 105                         if (res != NULL)
 106                                 *res = feature;
 107                         return (0);
 108                 }
 109         }
 110
 111         return (ENOENT);
 112 }
 113
 114 int
 115 zfeature_lookup_name(const char *name, zfeature_info_t **res)
 116 {
 117         int i;
 118
 119         for (i = 0; i < SPA_FEATURES; i++) {
 120                 zfeature_info_t *feature = &spa_feature_table[i];
 121                 if (strcmp(name, feature->fi_uname) == 0) {
 122                         if (res != NULL)
 123                                 *res = feature;
 124                         return (0);
 125                 }
 126         }
 127
 128         return (ENOENT);
 129 }
 130
 131 static void
 132 zfeature_register(int fid, const char *guid, const char *name, const char *desc,
 133     boolean_t readonly, boolean_t mos, zfeature_info_t **deps)
 134 {
 135         zfeature_info_t *feature = &spa_feature_table[fid];
 136         static zfeature_info_t *nodeps[] = { NULL };
 137
 138         ASSERT(name != NULL);
 139         ASSERT(desc != NULL);
 140         ASSERT(!readonly || !mos);
 141         ASSERT3U(fid, <, SPA_FEATURES);
 142         ASSERT(zfeature_is_valid_guid(guid));
 143
 144         if (deps == NULL)
 145                 deps = nodeps;
 146
 147         feature->fi_guid = guid;
 148         feature->fi_uname = name;
 149         feature->fi_desc = desc;
 150         feature->fi_can_readonly = readonly;
 151         feature->fi_mos = mos;
 152         feature->fi_depends = deps;
 153 }
 154
 155 void
 156 zpool_feature_init(void)
 157 {
 158         zfeature_register(SPA_FEATURE_ASYNC_DESTROY,
 159             "com.delphix:async_destroy", "async_destroy",
 160             "Destroy filesystems asynchronously.", B_TRUE, B_FALSE, NULL);
 161         zfeature_register(SPA_FEATURE_EMPTY_BPOBJ,
 162             "com.delphix:empty_bpobj", "empty_bpobj",
 163             "Snapshots use less space.", B_TRUE, B_FALSE, NULL);
 164         zfeature_register(SPA_FEATURE_LZ4_COMPRESS,
 165             "org.illumos:lz4_compress", "lz4_compress",
 166             "LZ4 compression algorithm support.", B_FALSE, B_FALSE, NULL);
 167 }