module/zfs/zcp_synctask.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * This file and its contents are supplied under the terms of the
   5  * Common Development and Distribution License ("CDDL"), version 1.0.
   6  * You may only use this file in accordance with the terms of version
   7  * 1.0 of the CDDL.
   8  *
   9  * A full copy of the text of the CDDL should have accompanied this
  10  * source.  A copy of the CDDL is also available via the Internet at
  11  * http://www.illumos.org/license/CDDL.
  12  *
  13  * CDDL HEADER END
  14  */
  15
  16 /*
  17  * Copyright (c) 2016, 2017 by Delphix. All rights reserved.
  18  */
  19
  20 #include <sys/lua/lua.h>
  21 #include <sys/lua/lauxlib.h>
  22
  23 #include <sys/zcp.h>
  24 #include <sys/dsl_dir.h>
  25 #include <sys/dsl_pool.h>
  26 #include <sys/dsl_prop.h>
  27 #include <sys/dsl_synctask.h>
  28 #include <sys/dsl_dataset.h>
  29 #include <sys/dsl_bookmark.h>
  30 #include <sys/dsl_destroy.h>
  31 #include <sys/dmu_objset.h>
  32 #include <sys/zfs_znode.h>
  33 #include <sys/zfeature.h>
  34 #include <sys/metaslab.h>
  35
  36 #define DST_AVG_BLKSHIFT 14
  37
  38 typedef int (zcp_synctask_func_t)(lua_State *, boolean_t, nvlist_t *);
  39 typedef struct zcp_synctask_info {
  40         const char *name;
  41         zcp_synctask_func_t *func;
  42         const zcp_arg_t pargs[4];
  43         const zcp_arg_t kwargs[2];
  44         zfs_space_check_t space_check;
  45         int blocks_modified;
  46 } zcp_synctask_info_t;
  47
  48 /*
  49  * Generic synctask interface for channel program syncfuncs.
  50  *
  51  * To perform some action in syncing context, we'd generally call
  52  * dsl_sync_task(), but since the Lua script is already running inside a
  53  * synctask we need to leave out some actions (such as acquiring the config
  54  * rwlock and performing space checks).
  55  *
  56  * If 'sync' is false, executes a dry run and returns the error code.
  57  *
  58  * If we are not running in syncing context and we are not doing a dry run
  59  * (meaning we are running a zfs.sync function in open-context) then we
  60  * return a Lua error.
  61  *
  62  * This function also handles common fatal error cases for channel program
  63  * library functions. If a fatal error occurs, err_dsname will be the dataset
  64  * name reported in error messages, if supplied.
  65  */
  66 static int
  67 zcp_sync_task(lua_State *state, dsl_checkfunc_t *checkfunc,
  68     dsl_syncfunc_t *syncfunc, void *arg, boolean_t sync, const char *err_dsname)
  69 {
  70         int err;
  71         zcp_run_info_t *ri = zcp_run_info(state);
  72
  73         err = checkfunc(arg, ri->zri_tx);
  74         if (!sync)
  75                 return (err);
  76
  77         if (!ri->zri_sync) {
  78                 return (luaL_error(state, "running functions from the zfs.sync "
  79                     "submodule requires passing sync=TRUE to "
  80                     "lzc_channel_program() (i.e. do not specify the \"-n\" "
  81                     "command line argument)"));
  82         }
  83
  84         if (err == 0) {
  85                 syncfunc(arg, ri->zri_tx);
  86         } else if (err == EIO) {
  87                 if (err_dsname != NULL) {
  88                         return (luaL_error(state,
  89                             "I/O error while accessing dataset '%s'",
  90                             err_dsname));
  91                 } else {
  92                         return (luaL_error(state,
  93                             "I/O error while accessing dataset."));
  94                 }
  95         }
  96
  97         return (err);
  98 }
  99
 100
 101 static int zcp_synctask_destroy(lua_State *, boolean_t, nvlist_t *);
 102 static zcp_synctask_info_t zcp_synctask_destroy_info = {
 103         .name = "destroy",
 104         .func = zcp_synctask_destroy,
 105         .pargs = {
 106             {.za_name = "filesystem | snapshot", .za_lua_type = LUA_TSTRING},
 107             {NULL, 0}
 108         },
 109         .kwargs = {
 110             {.za_name = "defer", .za_lua_type = LUA_TBOOLEAN},
 111             {NULL, 0}
 112         },
 113         .space_check = ZFS_SPACE_CHECK_DESTROY,
 114         .blocks_modified = 0
 115 };
 116
 117 /* ARGSUSED */
 118 static int
 119 zcp_synctask_destroy(lua_State *state, boolean_t sync, nvlist_t *err_details)
 120 {
 121         int err;
 122         const char *dsname = lua_tostring(state, 1);
 123
 124         boolean_t issnap = (strchr(dsname, '@') != NULL);
 125
 126         if (!issnap && !lua_isnil(state, 2)) {
 127                 return (luaL_error(state,
 128                     "'deferred' kwarg only supported for snapshots: %s",
 129                     dsname));
 130         }
 131
 132         if (issnap) {
 133                 dsl_destroy_snapshot_arg_t ddsa = { 0 };
 134                 ddsa.ddsa_name = dsname;
 135                 if (!lua_isnil(state, 2)) {
 136                         ddsa.ddsa_defer = lua_toboolean(state, 2);
 137                 } else {
 138                         ddsa.ddsa_defer = B_FALSE;
 139                 }
 140
 141                 err = zcp_sync_task(state, dsl_destroy_snapshot_check,
 142                     dsl_destroy_snapshot_sync, &ddsa, sync, dsname);
 143         } else {
 144                 dsl_destroy_head_arg_t ddha = { 0 };
 145                 ddha.ddha_name = dsname;
 146
 147                 err = zcp_sync_task(state, dsl_destroy_head_check,
 148                     dsl_destroy_head_sync, &ddha, sync, dsname);
 149         }
 150
 151         return (err);
 152 }
 153
 154 static int zcp_synctask_promote(lua_State *, boolean_t, nvlist_t *);
 155 static zcp_synctask_info_t zcp_synctask_promote_info = {
 156         .name = "promote",
 157         .func = zcp_synctask_promote,
 158         .pargs = {
 159             {.za_name = "clone", .za_lua_type = LUA_TSTRING},
 160             {NULL, 0}
 161         },
 162         .kwargs = {
 163             {NULL, 0}
 164         },
 165         .space_check = ZFS_SPACE_CHECK_RESERVED,
 166         .blocks_modified = 3
 167 };
 168
 169 static int
 170 zcp_synctask_promote(lua_State *state, boolean_t sync, nvlist_t *err_details)
 171 {
 172         int err;
 173         dsl_dataset_promote_arg_t ddpa = { 0 };
 174         const char *dsname = lua_tostring(state, 1);
 175         zcp_run_info_t *ri = zcp_run_info(state);
 176
 177         ddpa.ddpa_clonename = dsname;
 178         ddpa.err_ds = err_details;
 179         ddpa.cr = ri->zri_cred;
 180
 181         /*
 182          * If there was a snapshot name conflict, then err_ds will be filled
 183          * with a list of conflicting snapshot names.
 184          */
 185         err = zcp_sync_task(state, dsl_dataset_promote_check,
 186             dsl_dataset_promote_sync, &ddpa, sync, dsname);
 187
 188         return (err);
 189 }
 190
 191 static int zcp_synctask_rollback(lua_State *, boolean_t, nvlist_t *err_details);
 192 static zcp_synctask_info_t zcp_synctask_rollback_info = {
 193         .name = "rollback",
 194         .func = zcp_synctask_rollback,
 195         .space_check = ZFS_SPACE_CHECK_RESERVED,
 196         .blocks_modified = 1,
 197         .pargs = {
 198             {.za_name = "filesystem", .za_lua_type = LUA_TSTRING},
 199             {0, 0}
 200         },
 201         .kwargs = {
 202             {0, 0}
 203         }
 204 };
 205
 206 static int
 207 zcp_synctask_rollback(lua_State *state, boolean_t sync, nvlist_t *err_details)
 208 {
 209         int err;
 210         const char *dsname = lua_tostring(state, 1);
 211         dsl_dataset_rollback_arg_t ddra = { 0 };
 212
 213         ddra.ddra_fsname = dsname;
 214         ddra.ddra_result = err_details;
 215
 216         err = zcp_sync_task(state, dsl_dataset_rollback_check,
 217             dsl_dataset_rollback_sync, &ddra, sync, dsname);
 218
 219         return (err);
 220 }
 221
 222 static int zcp_synctask_snapshot(lua_State *, boolean_t, nvlist_t *);
 223 static zcp_synctask_info_t zcp_synctask_snapshot_info = {
 224         .name = "snapshot",
 225         .func = zcp_synctask_snapshot,
 226         .pargs = {
 227             {.za_name = "filesystem@snapname | volume@snapname",
 228             .za_lua_type = LUA_TSTRING},
 229             {NULL, 0}
 230         },
 231         .kwargs = {
 232             {NULL, 0}
 233         },
 234         .space_check = ZFS_SPACE_CHECK_NORMAL,
 235         .blocks_modified = 3
 236 };
 237
 238 /* ARGSUSED */
 239 static int
 240 zcp_synctask_snapshot(lua_State *state, boolean_t sync, nvlist_t *err_details)
 241 {
 242         int err;
 243         dsl_dataset_snapshot_arg_t ddsa = { 0 };
 244         const char *dsname = lua_tostring(state, 1);
 245         zcp_run_info_t *ri = zcp_run_info(state);
 246
 247         /*
 248          * On old pools, the ZIL must not be active when a snapshot is created,
 249          * but we can't suspend the ZIL because we're already in syncing
 250          * context.
 251          */
 252         if (spa_version(ri->zri_pool->dp_spa) < SPA_VERSION_FAST_SNAP) {
 253                 return (ENOTSUP);
 254         }
 255
 256         /*
 257          * We only allow for a single snapshot rather than a list, so the
 258          * error list output is unnecessary.
 259          */
 260         ddsa.ddsa_errors = NULL;
 261         ddsa.ddsa_props = NULL;
 262         ddsa.ddsa_cr = ri->zri_cred;
 263         ddsa.ddsa_snaps = fnvlist_alloc();
 264         fnvlist_add_boolean(ddsa.ddsa_snaps, dsname);
 265
 266         zcp_cleanup_handler_t *zch = zcp_register_cleanup(state,
 267             (zcp_cleanup_t *)&fnvlist_free, ddsa.ddsa_snaps);
 268
 269         err = zcp_sync_task(state, dsl_dataset_snapshot_check,
 270             dsl_dataset_snapshot_sync, &ddsa, sync, dsname);
 271
 272         zcp_deregister_cleanup(state, zch);
 273         fnvlist_free(ddsa.ddsa_snaps);
 274
 275         return (err);
 276 }
 277
 278 static int
 279 zcp_synctask_wrapper(lua_State *state)
 280 {
 281         int err;
 282         zcp_cleanup_handler_t *zch;
 283         int num_ret = 1;
 284         nvlist_t *err_details = fnvlist_alloc();
 285
 286         /*
 287          * Make sure err_details is properly freed, even if a fatal error is
 288          * thrown during the synctask.
 289          */
 290         zch = zcp_register_cleanup(state,
 291             (zcp_cleanup_t *)&fnvlist_free, err_details);
 292
 293         zcp_synctask_info_t *info = lua_touserdata(state, lua_upvalueindex(1));
 294         boolean_t sync = lua_toboolean(state, lua_upvalueindex(2));
 295
 296         zcp_run_info_t *ri = zcp_run_info(state);
 297         dsl_pool_t *dp = ri->zri_pool;
 298
 299         /* MOS space is triple-dittoed, so we multiply by 3. */
 300         uint64_t funcspace =
 301             ((uint64_t)info->blocks_modified << DST_AVG_BLKSHIFT) * 3;
 302
 303         zcp_parse_args(state, info->name, info->pargs, info->kwargs);
 304
 305         err = 0;
 306         if (info->space_check != ZFS_SPACE_CHECK_NONE) {
 307                 uint64_t quota = dsl_pool_unreserved_space(dp,
 308                     info->space_check);
 309                 uint64_t used = dsl_dir_phys(dp->dp_root_dir)->dd_used_bytes +
 310                     ri->zri_space_used;
 311
 312                 if (used + funcspace > quota) {
 313                         err = SET_ERROR(ENOSPC);
 314                 }
 315         }
 316
 317         if (err == 0) {
 318                 err = info->func(state, sync, err_details);
 319         }
 320
 321         if (err == 0) {
 322                 ri->zri_space_used += funcspace;
 323         }
 324
 325         lua_pushnumber(state, (lua_Number)err);
 326         if (fnvlist_num_pairs(err_details) > 0) {
 327                 (void) zcp_nvlist_to_lua(state, err_details, NULL, 0);
 328                 num_ret++;
 329         }
 330
 331         zcp_deregister_cleanup(state, zch);
 332         fnvlist_free(err_details);
 333
 334         return (num_ret);
 335 }
 336
 337 int
 338 zcp_load_synctask_lib(lua_State *state, boolean_t sync)
 339 {
 340         int i;
 341         zcp_synctask_info_t *zcp_synctask_funcs[] = {
 342                 &zcp_synctask_destroy_info,
 343                 &zcp_synctask_promote_info,
 344                 &zcp_synctask_rollback_info,
 345                 &zcp_synctask_snapshot_info,
 346                 NULL
 347         };
 348
 349         lua_newtable(state);
 350
 351         for (i = 0; zcp_synctask_funcs[i] != NULL; i++) {
 352                 zcp_synctask_info_t *info = zcp_synctask_funcs[i];
 353                 lua_pushlightuserdata(state, info);
 354                 lua_pushboolean(state, sync);
 355                 lua_pushcclosure(state, &zcp_synctask_wrapper, 2);
 356                 lua_setfield(state, -2, info->name);
 357                 info++;
 358         }
 359
 360         return (1);
 361 }