cmds-balance.c

   1 /*
   2  * This program is free software; you can redistribute it and/or
   3  * modify it under the terms of the GNU General Public
   4  * License v2 as published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   9  * General Public License for more details.
  10  *
  11  * You should have received a copy of the GNU General Public
  12  * License along with this program; if not, write to the
  13  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  14  * Boston, MA 021110-1307, USA.
  15  */
  16
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19 #include <string.h>
  20 #include <unistd.h>
  21 #include <getopt.h>
  22 #include <sys/ioctl.h>
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <fcntl.h>
  26 #include <errno.h>
  27
  28 #include "kerncompat.h"
  29 #include "ctree.h"
  30 #include "ioctl.h"
  31 #include "volumes.h"
  32
  33 #include "commands.h"
  34 #include "utils.h"
  35
  36 static const char * const balance_cmd_group_usage[] = {
  37         "btrfs balance <command> [options] <path>",
  38         "btrfs balance <path>",
  39         NULL
  40 };
  41
  42 static int parse_one_profile(const char *profile, u64 *flags)
  43 {
  44         if (!strcmp(profile, "raid0")) {
  45                 *flags |= BTRFS_BLOCK_GROUP_RAID0;
  46         } else if (!strcmp(profile, "raid1")) {
  47                 *flags |= BTRFS_BLOCK_GROUP_RAID1;
  48         } else if (!strcmp(profile, "raid10")) {
  49                 *flags |= BTRFS_BLOCK_GROUP_RAID10;
  50         } else if (!strcmp(profile, "raid5")) {
  51                 *flags |= BTRFS_BLOCK_GROUP_RAID5;
  52         } else if (!strcmp(profile, "raid6")) {
  53                 *flags |= BTRFS_BLOCK_GROUP_RAID6;
  54         } else if (!strcmp(profile, "dup")) {
  55                 *flags |= BTRFS_BLOCK_GROUP_DUP;
  56         } else if (!strcmp(profile, "single")) {
  57                 *flags |= BTRFS_AVAIL_ALLOC_BIT_SINGLE;
  58         } else {
  59                 error("unknown profile: %s", profile);
  60                 return 1;
  61         }
  62
  63         return 0;
  64 }
  65
  66 static int parse_profiles(char *profiles, u64 *flags)
  67 {
  68         char *this_char;
  69         char *save_ptr = NULL; /* Satisfy static checkers */
  70
  71         for (this_char = strtok_r(profiles, "|", &save_ptr);
  72              this_char != NULL;
  73              this_char = strtok_r(NULL, "|", &save_ptr)) {
  74                 if (parse_one_profile(this_char, flags))
  75                         return 1;
  76         }
  77
  78         return 0;
  79 }
  80
  81 static int parse_u64(const char *str, u64 *result)
  82 {
  83         char *endptr;
  84         u64 val;
  85
  86         val = strtoull(str, &endptr, 10);
  87         if (*endptr)
  88                 return 1;
  89
  90         *result = val;
  91         return 0;
  92 }
  93
  94 /*
  95  * Parse range that's missing some part that can be implicit:
  96  * a..b - exact range, a can be equal to b
  97  * a..  - implicitly unbounded maximum (end == (u64)-1)
  98  * ..b  - implicitly starting at 0
  99  * a    - invalid; unclear semantics, use parse_u64 instead
 100  *
 101  * Returned values are u64, value validation and interpretation should be done
 102  * by the caller.
 103  */
 104 static int parse_range(const char *range, u64 *start, u64 *end)
 105 {
 106         char *dots;
 107         char *endptr;
 108         const char *rest;
 109         int skipped = 0;
 110
 111         dots = strstr(range, "..");
 112         if (!dots)
 113                 return 1;
 114
 115         rest = dots + 2;
 116
 117         if (!*rest) {
 118                 *end = (u64)-1;
 119                 skipped++;
 120         } else {
 121                 *end = strtoull(rest, &endptr, 10);
 122                 if (*endptr)
 123                         return 1;
 124         }
 125         if (dots == range) {
 126                 *start = 0;
 127                 skipped++;
 128         } else {
 129                 *start = strtoull(range, &endptr, 10);
 130                 if (*endptr != 0 && *endptr != '.')
 131                         return 1;
 132         }
 133
 134         if (*start > *end) {
 135                 error("range %llu..%llu doesn't make sense",
 136                         (unsigned long long)*start,
 137                         (unsigned long long)*end);
 138                 return 1;
 139         }
 140
 141         if (skipped <= 1)
 142                 return 0;
 143
 144         return 1;
 145 }
 146
 147 /*
 148  * Parse range and check if start < end
 149  */
 150 static int parse_range_strict(const char *range, u64 *start, u64 *end)
 151 {
 152         if (parse_range(range, start, end) == 0) {
 153                 if (*start >= *end) {
 154                         error("range %llu..%llu not allowed",
 155                                 (unsigned long long)*start,
 156                                 (unsigned long long)*end);
 157                         return 1;
 158                 }
 159                 return 0;
 160         }
 161
 162         return 1;
 163 }
 164
 165 /*
 166  * Convert 64bit range to 32bit with boundary checks
 167  */
 168 static int range_to_u32(u64 start, u64 end, u32 *start32, u32 *end32)
 169 {
 170         if (start > (u32)-1)
 171                 return 1;
 172
 173         if (end != (u64)-1 && end > (u32)-1)
 174                 return 1;
 175
 176         *start32 = (u32)start;
 177         *end32 = (u32)end;
 178
 179         return 0;
 180 }
 181
 182 __attribute__ ((unused))
 183 static int parse_range_u32(const char *range, u32 *start, u32 *end)
 184 {
 185         u64 tmp_start;
 186         u64 tmp_end;
 187
 188         if (parse_range(range, &tmp_start, &tmp_end))
 189                 return 1;
 190
 191         if (range_to_u32(tmp_start, tmp_end, start, end))
 192                 return 1;
 193
 194         return 0;
 195 }
 196
 197 __attribute__ ((unused))
 198 static void print_range(u64 start, u64 end)
 199 {
 200         if (start)
 201                 printf("%llu", (unsigned long long)start);
 202         printf("..");
 203         if (end != (u64)-1)
 204                 printf("%llu", (unsigned long long)end);
 205 }
 206
 207 __attribute__ ((unused))
 208 static void print_range_u32(u32 start, u32 end)
 209 {
 210         if (start)
 211                 printf("%u", start);
 212         printf("..");
 213         if (end != (u32)-1)
 214                 printf("%u", end);
 215 }
 216
 217 static int parse_filters(char *filters, struct btrfs_balance_args *args)
 218 {
 219         char *this_char;
 220         char *value;
 221         char *save_ptr = NULL; /* Satisfy static checkers */
 222
 223         if (!filters)
 224                 return 0;
 225
 226         for (this_char = strtok_r(filters, ",", &save_ptr);
 227              this_char != NULL;
 228              this_char = strtok_r(NULL, ",", &save_ptr)) {
 229                 if ((value = strchr(this_char, '=')) != NULL)
 230                         *value++ = 0;
 231                 if (!strcmp(this_char, "profiles")) {
 232                         if (!value || !*value) {
 233                                 error("the profiles filter requires an argument");
 234                                 return 1;
 235                         }
 236                         if (parse_profiles(value, &args->profiles)) {
 237                                 error("invalid profiles argument");
 238                                 return 1;
 239                         }
 240                         args->flags |= BTRFS_BALANCE_ARGS_PROFILES;
 241                 } else if (!strcmp(this_char, "usage")) {
 242                         if (!value || !*value) {
 243                                 error("the usage filter requires an argument");
 244                                 return 1;
 245                         }
 246                         if (parse_u64(value, &args->usage)) {
 247                                 if (parse_range_u32(value, &args->usage_min,
 248                                                         &args->usage_max)) {
 249                                         error("invalid usage argument: %s",
 250                                                 value);
 251                                         return 1;
 252                                 }
 253                                 if (args->usage_max > 100) {
 254                                         error("invalid usage argument: %s",
 255                                                 value);
 256                                 }
 257                                 args->flags &= ~BTRFS_BALANCE_ARGS_USAGE;
 258                                 args->flags |= BTRFS_BALANCE_ARGS_USAGE_RANGE;
 259                         } else {
 260                                 if (args->usage > 100) {
 261                                         error("invalid usage argument: %s",
 262                                                 value);
 263                                         return 1;
 264                                 }
 265                                 args->flags &= ~BTRFS_BALANCE_ARGS_USAGE_RANGE;
 266                                 args->flags |= BTRFS_BALANCE_ARGS_USAGE;
 267                         }
 268                         args->flags |= BTRFS_BALANCE_ARGS_USAGE;
 269                 } else if (!strcmp(this_char, "devid")) {
 270                         if (!value || !*value) {
 271                                 error("the devid filter requires an argument");
 272                                 return 1;
 273                         }
 274                         if (parse_u64(value, &args->devid) || args->devid == 0) {
 275                                 error("invalid devid argument: %s", value);
 276                                 return 1;
 277                         }
 278                         args->flags |= BTRFS_BALANCE_ARGS_DEVID;
 279                 } else if (!strcmp(this_char, "drange")) {
 280                         if (!value || !*value) {
 281                                 error("the drange filter requires an argument");
 282                                 return 1;
 283                         }
 284                         if (parse_range_strict(value, &args->pstart, &args->pend)) {
 285                                 error("invalid drange argument");
 286                                 return 1;
 287                         }
 288                         args->flags |= BTRFS_BALANCE_ARGS_DRANGE;
 289                 } else if (!strcmp(this_char, "vrange")) {
 290                         if (!value || !*value) {
 291                                 error("the vrange filter requires an argument");
 292                                 return 1;
 293                         }
 294                         if (parse_range_strict(value, &args->vstart, &args->vend)) {
 295                                 error("invalid vrange argument");
 296                                 return 1;
 297                         }
 298                         args->flags |= BTRFS_BALANCE_ARGS_VRANGE;
 299                 } else if (!strcmp(this_char, "convert")) {
 300                         if (!value || !*value) {
 301                                 error("the convert option requires an argument");
 302                                 return 1;
 303                         }
 304                         if (parse_one_profile(value, &args->target)) {
 305                                 error("invalid convert argument");
 306                                 return 1;
 307                         }
 308                         args->flags |= BTRFS_BALANCE_ARGS_CONVERT;
 309                 } else if (!strcmp(this_char, "soft")) {
 310                         args->flags |= BTRFS_BALANCE_ARGS_SOFT;
 311                 } else if (!strcmp(this_char, "limit")) {
 312                         if (!value || !*value) {
 313                                 error("the limit filter requires an argument");
 314                                 return 1;
 315                         }
 316                         if (parse_u64(value, &args->limit)) {
 317                                 if (parse_range_u32(value, &args->limit_min,
 318                                                         &args->limit_max)) {
 319                                         error("Invalid limit argument: %s",
 320                                                value);
 321                                         return 1;
 322                                 }
 323                                 args->flags &= ~BTRFS_BALANCE_ARGS_LIMIT;
 324                                 args->flags |= BTRFS_BALANCE_ARGS_LIMIT_RANGE;
 325                         } else {
 326                                 args->flags &= ~BTRFS_BALANCE_ARGS_LIMIT_RANGE;
 327                                 args->flags |= BTRFS_BALANCE_ARGS_LIMIT;
 328                         }
 329                 } else if (!strcmp(this_char, "stripes")) {
 330                         if (!value || !*value) {
 331                                 error("the stripes filter requires an argument");
 332                                 return 1;
 333                         }
 334                         if (parse_range_u32(value, &args->stripes_min,
 335                                             &args->stripes_max)) {
 336                                 error("invalid stripes argument");
 337                                 return 1;
 338                         }
 339                         args->flags |= BTRFS_BALANCE_ARGS_STRIPES_RANGE;
 340                 } else {
 341                         error("unrecognized balance option: %s", this_char);
 342                         return 1;
 343                 }
 344         }
 345
 346         return 0;
 347 }
 348
 349 static void dump_balance_args(struct btrfs_balance_args *args)
 350 {
 351         if (args->flags & BTRFS_BALANCE_ARGS_CONVERT) {
 352                 printf("converting, target=%llu, soft is %s",
 353                        (unsigned long long)args->target,
 354                        (args->flags & BTRFS_BALANCE_ARGS_SOFT) ? "on" : "off");
 355         } else {
 356                 printf("balancing");
 357         }
 358
 359         if (args->flags & BTRFS_BALANCE_ARGS_PROFILES)
 360                 printf(", profiles=%llu", (unsigned long long)args->profiles);
 361         if (args->flags & BTRFS_BALANCE_ARGS_USAGE)
 362                 printf(", usage=%llu", (unsigned long long)args->usage);
 363         if (args->flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) {
 364                 printf(", usage=");
 365                 print_range_u32(args->usage_min, args->usage_max);
 366         }
 367         if (args->flags & BTRFS_BALANCE_ARGS_DEVID)
 368                 printf(", devid=%llu", (unsigned long long)args->devid);
 369         if (args->flags & BTRFS_BALANCE_ARGS_DRANGE)
 370                 printf(", drange=%llu..%llu",
 371                        (unsigned long long)args->pstart,
 372                        (unsigned long long)args->pend);
 373         if (args->flags & BTRFS_BALANCE_ARGS_VRANGE)
 374                 printf(", vrange=%llu..%llu",
 375                        (unsigned long long)args->vstart,
 376                        (unsigned long long)args->vend);
 377         if (args->flags & BTRFS_BALANCE_ARGS_LIMIT)
 378                 printf(", limit=%llu", (unsigned long long)args->limit);
 379         if (args->flags & BTRFS_BALANCE_ARGS_LIMIT_RANGE) {
 380                 printf(", limit=");
 381                 print_range_u32(args->limit_min, args->limit_max);
 382         }
 383         if (args->flags & BTRFS_BALANCE_ARGS_STRIPES_RANGE) {
 384                 printf(", stripes=");
 385                 print_range_u32(args->stripes_min, args->stripes_max);
 386         }
 387
 388         printf("\n");
 389 }
 390
 391 static void dump_ioctl_balance_args(struct btrfs_ioctl_balance_args *args)
 392 {
 393         printf("Dumping filters: flags 0x%llx, state 0x%llx, force is %s\n",
 394                (unsigned long long)args->flags, (unsigned long long)args->state,
 395                (args->flags & BTRFS_BALANCE_FORCE) ? "on" : "off");
 396         if (args->flags & BTRFS_BALANCE_DATA) {
 397                 printf("  DATA (flags 0x%llx): ",
 398                        (unsigned long long)args->data.flags);
 399                 dump_balance_args(&args->data);
 400         }
 401         if (args->flags & BTRFS_BALANCE_METADATA) {
 402                 printf("  METADATA (flags 0x%llx): ",
 403                        (unsigned long long)args->meta.flags);
 404                 dump_balance_args(&args->meta);
 405         }
 406         if (args->flags & BTRFS_BALANCE_SYSTEM) {
 407                 printf("  SYSTEM (flags 0x%llx): ",
 408                        (unsigned long long)args->sys.flags);
 409                 dump_balance_args(&args->sys);
 410         }
 411 }
 412
 413 static int do_balance_v1(int fd)
 414 {
 415         struct btrfs_ioctl_vol_args args;
 416         int ret;
 417
 418         memset(&args, 0, sizeof(args));
 419         ret = ioctl(fd, BTRFS_IOC_BALANCE, &args);
 420         return ret;
 421 }
 422
 423 enum {
 424         BALANCE_START_FILTERS = 1 << 0,
 425         BALANCE_START_NOWARN  = 1 << 1
 426 };
 427
 428 static int do_balance(const char *path, struct btrfs_ioctl_balance_args *args,
 429                       unsigned flags)
 430 {
 431         int fd;
 432         int ret;
 433         DIR *dirstream = NULL;
 434
 435         fd = btrfs_open_dir(path, &dirstream, 1);
 436         if (fd < 0)
 437                 return 1;
 438
 439         if (!(flags & BALANCE_START_FILTERS) && !(flags & BALANCE_START_NOWARN)) {
 440                 int delay = 10;
 441
 442                 printf("WARNING:\n\n");
 443                 printf("\tFull balance without filters requested. This operation is very\n");
 444                 printf("\tintense and takes potentially very long. It is recommended to\n");
 445                 printf("\tuse the balance filters to narrow down the balanced data.\n");
 446                 printf("\tUse 'btrfs balance start --full-balance' option to skip this\n");
 447                 printf("\twarning. The operation will start in %d seconds.\n", delay);
 448                 printf("\tUse Ctrl-C to stop it.\n");
 449                 while (delay) {
 450                         printf("%2d", delay--);
 451                         fflush(stdout);
 452                         sleep(1);
 453                 }
 454                 printf("\nStarting balance without any filters.\n");
 455         }
 456
 457         ret = ioctl(fd, BTRFS_IOC_BALANCE_V2, args);
 458         if (ret < 0) {
 459                 /*
 460                  * older kernels don't have the new balance ioctl, try the
 461                  * old one.  But, the old one doesn't know any filters, so
 462                  * don't fall back if they tried to use the fancy new things
 463                  */
 464                 if (errno == ENOTTY && !(flags & BALANCE_START_FILTERS)) {
 465                         ret = do_balance_v1(fd);
 466                         if (ret == 0)
 467                                 goto out;
 468                 }
 469
 470                 if (errno == ECANCELED) {
 471                         if (args->state & BTRFS_BALANCE_STATE_PAUSE_REQ)
 472                                 fprintf(stderr, "balance paused by user\n");
 473                         if (args->state & BTRFS_BALANCE_STATE_CANCEL_REQ)
 474                                 fprintf(stderr, "balance canceled by user\n");
 475                         ret = 0;
 476                 } else {
 477                         error("error during balancing '%s': %s", path,
 478                                         strerror(errno));
 479                         if (errno != EINPROGRESS)
 480                                 fprintf(stderr,
 481                         "There may be more info in syslog - try dmesg | tail\n");
 482                         ret = 1;
 483                 }
 484         } else {
 485                 printf("Done, had to relocate %llu out of %llu chunks\n",
 486                        (unsigned long long)args->stat.completed,
 487                        (unsigned long long)args->stat.considered);
 488                 ret = 0;
 489         }
 490
 491 out:
 492         close_file_or_dir(fd, dirstream);
 493         return ret;
 494 }
 495
 496 static const char * const cmd_balance_start_usage[] = {
 497         "btrfs balance start [options] <path>",
 498         "Balance chunks across the devices",
 499         "Balance and/or convert (change allocation profile of) chunks that",
 500         "passed all filters in a comma-separated list of filters for a",
 501         "particular chunk type.  If filter list is not given balance all",
 502         "chunks of that type.  In case none of the -d, -m or -s options is",
 503         "given balance all chunks in a filesystem. This is potentially",
 504         "long operation and the user is warned before this start, with",
 505         "a delay to stop it.",
 506         "",
 507         "-d[filters]    act on data chunks",
 508         "-m[filters]    act on metadata chunks",
 509         "-s[filters]    act on system chunks (only under -f)",
 510         "-v             be verbose",
 511         "-f             force reducing of metadata integrity",
 512         "--full-balance do not print warning and do not delay start",
 513         "--background|--bg",
 514         "               run the balance as a background process",
 515         NULL
 516 };
 517
 518 static int cmd_balance_start(int argc, char **argv)
 519 {
 520         struct btrfs_ioctl_balance_args args;
 521         struct btrfs_balance_args *ptrs[] = { &args.data, &args.sys,
 522                                                 &args.meta, NULL };
 523         int force = 0;
 524         int verbose = 0;
 525         int background = 0;
 526         unsigned start_flags = 0;
 527         int i;
 528
 529         memset(&args, 0, sizeof(args));
 530
 531         while (1) {
 532                 enum { GETOPT_VAL_FULL_BALANCE = 256,
 533                         GETOPT_VAL_BACKGROUND = 257 };
 534                 static const struct option longopts[] = {
 535                         { "data", optional_argument, NULL, 'd'},
 536                         { "metadata", optional_argument, NULL, 'm' },
 537                         { "system", optional_argument, NULL, 's' },
 538                         { "force", no_argument, NULL, 'f' },
 539                         { "verbose", no_argument, NULL, 'v' },
 540                         { "full-balance", no_argument, NULL,
 541                                 GETOPT_VAL_FULL_BALANCE },
 542                         { "background", no_argument, NULL,
 543                                 GETOPT_VAL_BACKGROUND },
 544                         { "bg", no_argument, NULL, GETOPT_VAL_BACKGROUND },
 545                         { NULL, 0, NULL, 0 }
 546                 };
 547
 548                 int opt = getopt_long(argc, argv, "d::s::m::fv", longopts, NULL);
 549                 if (opt < 0)
 550                         break;
 551
 552                 switch (opt) {
 553                 case 'd':
 554                         start_flags |= BALANCE_START_FILTERS;
 555                         args.flags |= BTRFS_BALANCE_DATA;
 556
 557                         if (parse_filters(optarg, &args.data))
 558                                 return 1;
 559                         break;
 560                 case 's':
 561                         start_flags |= BALANCE_START_FILTERS;
 562                         args.flags |= BTRFS_BALANCE_SYSTEM;
 563
 564                         if (parse_filters(optarg, &args.sys))
 565                                 return 1;
 566                         break;
 567                 case 'm':
 568                         start_flags |= BALANCE_START_FILTERS;
 569                         args.flags |= BTRFS_BALANCE_METADATA;
 570
 571                         if (parse_filters(optarg, &args.meta))
 572                                 return 1;
 573                         break;
 574                 case 'f':
 575                         force = 1;
 576                         break;
 577                 case 'v':
 578                         verbose = 1;
 579                         break;
 580                 case GETOPT_VAL_FULL_BALANCE:
 581                         start_flags |= BALANCE_START_NOWARN;
 582                         break;
 583                 case GETOPT_VAL_BACKGROUND:
 584                         background = 1;
 585                         break;
 586                 default:
 587                         usage(cmd_balance_start_usage);
 588                 }
 589         }
 590
 591         if (check_argc_exact(argc - optind, 1))
 592                 usage(cmd_balance_start_usage);
 593
 594         /*
 595          * allow -s only under --force, otherwise do with system chunks
 596          * the same thing we were ordered to do with meta chunks
 597          */
 598         if (args.flags & BTRFS_BALANCE_SYSTEM) {
 599                 if (!force) {
 600                         error(
 601                             "Refusing to explicitly operate on system chunks.\n"
 602                             "Pass --force if you really want to do that.");
 603                         return 1;
 604                 }
 605         } else if (args.flags & BTRFS_BALANCE_METADATA) {
 606                 args.flags |= BTRFS_BALANCE_SYSTEM;
 607                 memcpy(&args.sys, &args.meta,
 608                         sizeof(struct btrfs_balance_args));
 609         }
 610
 611         if (!(start_flags & BALANCE_START_FILTERS)) {
 612                 /* relocate everything - no filters */
 613                 args.flags |= BTRFS_BALANCE_TYPE_MASK;
 614         }
 615
 616         /* drange makes sense only when devid is set */
 617         for (i = 0; ptrs[i]; i++) {
 618                 if ((ptrs[i]->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
 619                     !(ptrs[i]->flags & BTRFS_BALANCE_ARGS_DEVID)) {
 620                         error("drange filter must be used with devid filter");
 621                         return 1;
 622                 }
 623         }
 624
 625         /* soft makes sense only when convert for corresponding type is set */
 626         for (i = 0; ptrs[i]; i++) {
 627                 if ((ptrs[i]->flags & BTRFS_BALANCE_ARGS_SOFT) &&
 628                     !(ptrs[i]->flags & BTRFS_BALANCE_ARGS_CONVERT)) {
 629                         error("'soft' option can be used only when converting profiles");
 630                         return 1;
 631                 }
 632         }
 633
 634         if (force)
 635                 args.flags |= BTRFS_BALANCE_FORCE;
 636         if (verbose)
 637                 dump_ioctl_balance_args(&args);
 638         if (background) {
 639                 switch (fork()) {
 640                 case (-1):
 641                         error("unable to fork to run balance in background");
 642                         return 1;
 643                 case (0):
 644                         setsid();
 645                         switch(fork()) {
 646                         case (-1):
 647                                 error(
 648                                 "unable to fork to run balance in background");
 649                                 exit(1);
 650                         case (0):
 651                                 /*
 652                                  * Read the return value to silence compiler
 653                                  * warning. Change to / should succeed and
 654                                  * we're not in a security-sensitive context.
 655                                  */
 656                                 i = chdir("/");
 657                                 close(0);
 658                                 close(1);
 659                                 close(2);
 660                                 open("/dev/null", O_RDONLY);
 661                                 open("/dev/null", O_WRONLY);
 662                                 open("/dev/null", O_WRONLY);
 663                                 break;
 664                         default:
 665                                 exit(0);
 666                         }
 667                         break;
 668                 default:
 669                         exit(0);
 670                 }
 671         }
 672
 673         return do_balance(argv[optind], &args, start_flags);
 674 }
 675
 676 static const char * const cmd_balance_pause_usage[] = {
 677         "btrfs balance pause <path>",
 678         "Pause running balance",
 679         NULL
 680 };
 681
 682 static int cmd_balance_pause(int argc, char **argv)
 683 {
 684         const char *path;
 685         int fd;
 686         int ret;
 687         DIR *dirstream = NULL;
 688
 689         clean_args_no_options(argc, argv, cmd_balance_pause_usage);
 690
 691         if (check_argc_exact(argc - optind, 1))
 692                 usage(cmd_balance_pause_usage);
 693
 694         path = argv[optind];
 695
 696         fd = btrfs_open_dir(path, &dirstream, 1);
 697         if (fd < 0)
 698                 return 1;
 699
 700         ret = ioctl(fd, BTRFS_IOC_BALANCE_CTL, BTRFS_BALANCE_CTL_PAUSE);
 701         if (ret < 0) {
 702                 error("balance pause on '%s' failed: %s", path,
 703                         (errno == ENOTCONN) ? "Not running" : strerror(errno));
 704                 if (errno == ENOTCONN)
 705                         ret = 2;
 706                 else
 707                         ret = 1;
 708         }
 709
 710         close_file_or_dir(fd, dirstream);
 711         return ret;
 712 }
 713
 714 static const char * const cmd_balance_cancel_usage[] = {
 715         "btrfs balance cancel <path>",
 716         "Cancel running or paused balance",
 717         NULL
 718 };
 719
 720 static int cmd_balance_cancel(int argc, char **argv)
 721 {
 722         const char *path;
 723         int fd;
 724         int ret;
 725         DIR *dirstream = NULL;
 726
 727         clean_args_no_options(argc, argv, cmd_balance_cancel_usage);
 728
 729         if (check_argc_exact(argc - optind, 1))
 730                 usage(cmd_balance_cancel_usage);
 731
 732         path = argv[optind];
 733
 734         fd = btrfs_open_dir(path, &dirstream, 1);
 735         if (fd < 0)
 736                 return 1;
 737
 738         ret = ioctl(fd, BTRFS_IOC_BALANCE_CTL, BTRFS_BALANCE_CTL_CANCEL);
 739         if (ret < 0) {
 740                 error("balance cancel on '%s' failed: %s", path,
 741                         (errno == ENOTCONN) ? "Not in progress" : strerror(errno));
 742                 if (errno == ENOTCONN)
 743                         ret = 2;
 744                 else
 745                         ret = 1;
 746         }
 747
 748         close_file_or_dir(fd, dirstream);
 749         return ret;
 750 }
 751
 752 static const char * const cmd_balance_resume_usage[] = {
 753         "btrfs balance resume <path>",
 754         "Resume interrupted balance",
 755         NULL
 756 };
 757
 758 static int cmd_balance_resume(int argc, char **argv)
 759 {
 760         struct btrfs_ioctl_balance_args args;
 761         const char *path;
 762         DIR *dirstream = NULL;
 763         int fd;
 764         int ret;
 765
 766         clean_args_no_options(argc, argv, cmd_balance_resume_usage);
 767
 768         if (check_argc_exact(argc - optind, 1))
 769                 usage(cmd_balance_resume_usage);
 770
 771         path = argv[optind];
 772
 773         fd = btrfs_open_dir(path, &dirstream, 1);
 774         if (fd < 0)
 775                 return 1;
 776
 777         memset(&args, 0, sizeof(args));
 778         args.flags |= BTRFS_BALANCE_RESUME;
 779
 780         ret = ioctl(fd, BTRFS_IOC_BALANCE_V2, &args);
 781         if (ret < 0) {
 782                 if (errno == ECANCELED) {
 783                         if (args.state & BTRFS_BALANCE_STATE_PAUSE_REQ)
 784                                 fprintf(stderr, "balance paused by user\n");
 785                         if (args.state & BTRFS_BALANCE_STATE_CANCEL_REQ)
 786                                 fprintf(stderr, "balance canceled by user\n");
 787                 } else if (errno == ENOTCONN || errno == EINPROGRESS) {
 788                         error("balance resume on '%s' failed: %s", path,
 789                                 (errno == ENOTCONN) ? "Not in progress" :
 790                                                   "Already running");
 791                         if (errno == ENOTCONN)
 792                                 ret = 2;
 793                         else
 794                                 ret = 1;
 795                 } else {
 796                         error("error during balancing '%s': %s\n"
 797                           "There may be more info in syslog - try dmesg | tail",
 798                                 path, strerror(errno));
 799                         ret = 1;
 800                 }
 801         } else {
 802                 printf("Done, had to relocate %llu out of %llu chunks\n",
 803                        (unsigned long long)args.stat.completed,
 804                        (unsigned long long)args.stat.considered);
 805         }
 806
 807         close_file_or_dir(fd, dirstream);
 808         return ret;
 809 }
 810
 811 static const char * const cmd_balance_status_usage[] = {
 812         "btrfs balance status [-v] <path>",
 813         "Show status of running or paused balance",
 814         "",
 815         "-v     be verbose",
 816         NULL
 817 };
 818
 819 /* Checks the status of the balance if any
 820  * return codes:
 821  *   2 : Error failed to know if there is any pending balance
 822  *   1 : Successful to know status of a pending balance
 823  *   0 : When there is no pending balance or completed
 824  */
 825 static int cmd_balance_status(int argc, char **argv)
 826 {
 827         struct btrfs_ioctl_balance_args args;
 828         const char *path;
 829         DIR *dirstream = NULL;
 830         int fd;
 831         int verbose = 0;
 832         int ret;
 833
 834         while (1) {
 835                 int opt;
 836                 static const struct option longopts[] = {
 837                         { "verbose", no_argument, NULL, 'v' },
 838                         { NULL, 0, NULL, 0 }
 839                 };
 840
 841                 opt = getopt_long(argc, argv, "v", longopts, NULL);
 842                 if (opt < 0)
 843                         break;
 844
 845                 switch (opt) {
 846                 case 'v':
 847                         verbose = 1;
 848                         break;
 849                 default:
 850                         usage(cmd_balance_status_usage);
 851                 }
 852         }
 853
 854         if (check_argc_exact(argc - optind, 1))
 855                 usage(cmd_balance_status_usage);
 856
 857         path = argv[optind];
 858
 859         fd = btrfs_open_dir(path, &dirstream, 1);
 860         if (fd < 0)
 861                 return 2;
 862
 863         ret = ioctl(fd, BTRFS_IOC_BALANCE_PROGRESS, &args);
 864         if (ret < 0) {
 865                 if (errno == ENOTCONN) {
 866                         printf("No balance found on '%s'\n", path);
 867                         ret = 0;
 868                         goto out;
 869                 }
 870                 error("balance status on '%s' failed: %s", path, strerror(errno));
 871                 ret = 2;
 872                 goto out;
 873         }
 874
 875         if (args.state & BTRFS_BALANCE_STATE_RUNNING) {
 876                 printf("Balance on '%s' is running", path);
 877                 if (args.state & BTRFS_BALANCE_STATE_CANCEL_REQ)
 878                         printf(", cancel requested\n");
 879                 else if (args.state & BTRFS_BALANCE_STATE_PAUSE_REQ)
 880                         printf(", pause requested\n");
 881                 else
 882                         printf("\n");
 883         } else {
 884                 printf("Balance on '%s' is paused\n", path);
 885         }
 886
 887         printf("%llu out of about %llu chunks balanced (%llu considered), "
 888                "%3.f%% left\n", (unsigned long long)args.stat.completed,
 889                (unsigned long long)args.stat.expected,
 890                (unsigned long long)args.stat.considered,
 891                100 * (1 - (float)args.stat.completed/args.stat.expected));
 892
 893         if (verbose)
 894                 dump_ioctl_balance_args(&args);
 895
 896         ret = 1;
 897 out:
 898         close_file_or_dir(fd, dirstream);
 899         return ret;
 900 }
 901
 902 static int cmd_balance_full(int argc, char **argv)
 903 {
 904         struct btrfs_ioctl_balance_args args;
 905
 906         memset(&args, 0, sizeof(args));
 907         args.flags |= BTRFS_BALANCE_TYPE_MASK;
 908
 909         return do_balance(argv[1], &args, BALANCE_START_NOWARN);
 910 }
 911
 912 static const char balance_cmd_group_info[] =
 913 "balance data across devices, or change block groups using filters";
 914
 915 const struct cmd_group balance_cmd_group = {
 916         balance_cmd_group_usage, balance_cmd_group_info, {
 917                 { "start", cmd_balance_start, cmd_balance_start_usage, NULL, 0 },
 918                 { "pause", cmd_balance_pause, cmd_balance_pause_usage, NULL, 0 },
 919                 { "cancel", cmd_balance_cancel, cmd_balance_cancel_usage, NULL, 0 },
 920                 { "resume", cmd_balance_resume, cmd_balance_resume_usage, NULL, 0 },
 921                 { "status", cmd_balance_status, cmd_balance_status_usage, NULL, 0 },
 922                 { "--full-balance", cmd_balance_full, NULL, NULL, 1 },
 923                 NULL_CMD_STRUCT
 924         }
 925 };
 926
 927 int cmd_balance(int argc, char **argv)
 928 {
 929         if (argc == 2 && strcmp("start", argv[1]) != 0) {
 930                 /* old 'btrfs filesystem balance <path>' syntax */
 931                 struct btrfs_ioctl_balance_args args;
 932
 933                 memset(&args, 0, sizeof(args));
 934                 args.flags |= BTRFS_BALANCE_TYPE_MASK;
 935
 936                 return do_balance(argv[1], &args, 0);
 937         }
 938
 939         return handle_command_group(&balance_cmd_group, argc, argv);
 940 }