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 #include "help.h"
  36
  37 static const char * const balance_cmd_group_usage[] = {
  38         "btrfs balance <command> [options] <path>",
  39         "btrfs balance <path>",
  40         NULL
  41 };
  42
  43 static int parse_one_profile(const char *profile, u64 *flags)
  44 {
  45         if (!strcmp(profile, "raid0")) {
  46                 *flags |= BTRFS_BLOCK_GROUP_RAID0;
  47         } else if (!strcmp(profile, "raid1")) {
  48                 *flags |= BTRFS_BLOCK_GROUP_RAID1;
  49         } else if (!strcmp(profile, "raid10")) {
  50                 *flags |= BTRFS_BLOCK_GROUP_RAID10;
  51         } else if (!strcmp(profile, "raid5")) {
  52                 *flags |= BTRFS_BLOCK_GROUP_RAID5;
  53         } else if (!strcmp(profile, "raid6")) {
  54                 *flags |= BTRFS_BLOCK_GROUP_RAID6;
  55         } else if (!strcmp(profile, "dup")) {
  56                 *flags |= BTRFS_BLOCK_GROUP_DUP;
  57         } else if (!strcmp(profile, "single")) {
  58                 *flags |= BTRFS_AVAIL_ALLOC_BIT_SINGLE;
  59         } else {
  60                 error("unknown profile: %s", profile);
  61                 return 1;
  62         }
  63
  64         return 0;
  65 }
  66
  67 static int parse_profiles(char *profiles, u64 *flags)
  68 {
  69         char *this_char;
  70         char *save_ptr = NULL; /* Satisfy static checkers */
  71
  72         for (this_char = strtok_r(profiles, "|", &save_ptr);
  73              this_char != NULL;
  74              this_char = strtok_r(NULL, "|", &save_ptr)) {
  75                 if (parse_one_profile(this_char, flags))
  76                         return 1;
  77         }
  78
  79         return 0;
  80 }
  81
  82 static int parse_u64(const char *str, u64 *result)
  83 {
  84         char *endptr;
  85         u64 val;
  86
  87         val = strtoull(str, &endptr, 10);
  88         if (*endptr)
  89                 return 1;
  90
  91         *result = val;
  92         return 0;
  93 }
  94
  95 /*
  96  * Parse range that's missing some part that can be implicit:
  97  * a..b - exact range, a can be equal to b
  98  * a..  - implicitly unbounded maximum (end == (u64)-1)
  99  * ..b  - implicitly starting at 0
 100  * a    - invalid; unclear semantics, use parse_u64 instead
 101  *
 102  * Returned values are u64, value validation and interpretation should be done
 103  * by the caller.
 104  */
 105 static int parse_range(const char *range, u64 *start, u64 *end)
 106 {
 107         char *dots;
 108         char *endptr;
 109         const char *rest;
 110         int skipped = 0;
 111
 112         dots = strstr(range, "..");
 113         if (!dots)
 114                 return 1;
 115
 116         rest = dots + 2;
 117
 118         if (!*rest) {
 119                 *end = (u64)-1;
 120                 skipped++;
 121         } else {
 122                 *end = strtoull(rest, &endptr, 10);
 123                 if (*endptr)
 124                         return 1;
 125         }
 126         if (dots == range) {
 127                 *start = 0;
 128                 skipped++;
 129         } else {
 130                 *start = strtoull(range, &endptr, 10);
 131                 if (*endptr != 0 && *endptr != '.')
 132                         return 1;
 133         }
 134
 135         if (*start > *end) {
 136                 error("range %llu..%llu doesn't make sense",
 137                         (unsigned long long)*start,
 138                         (unsigned long long)*end);
 139                 return 1;
 140         }
 141
 142         if (skipped <= 1)
 143                 return 0;
 144
 145         return 1;
 146 }
 147
 148 /*
 149  * Parse range and check if start < end
 150  */
 151 static int parse_range_strict(const char *range, u64 *start, u64 *end)
 152 {
 153         if (parse_range(range, start, end) == 0) {
 154                 if (*start >= *end) {
 155                         error("range %llu..%llu not allowed",
 156                                 (unsigned long long)*start,
 157                                 (unsigned long long)*end);
 158                         return 1;
 159                 }
 160                 return 0;
 161         }
 162
 163         return 1;
 164 }
 165
 166 /*
 167  * Convert 64bit range to 32bit with boundary checks
 168  */
 169 static int range_to_u32(u64 start, u64 end, u32 *start32, u32 *end32)
 170 {
 171         if (start > (u32)-1)
 172                 return 1;
 173
 174         if (end != (u64)-1 && end > (u32)-1)
 175                 return 1;
 176
 177         *start32 = (u32)start;
 178         *end32 = (u32)end;
 179
 180         return 0;
 181 }
 182
 183 __attribute__ ((unused))
 184 static int parse_range_u32(const char *range, u32 *start, u32 *end)
 185 {
 186         u64 tmp_start;
 187         u64 tmp_end;
 188
 189         if (parse_range(range, &tmp_start, &tmp_end))
 190                 return 1;
 191
 192         if (range_to_u32(tmp_start, tmp_end, start, end))
 193                 return 1;
 194
 195         return 0;
 196 }
 197
 198 __attribute__ ((unused))
 199 static void print_range(u64 start, u64 end)
 200 {
 201         if (start)
 202                 printf("%llu", (unsigned long long)start);
 203         printf("..");
 204         if (end != (u64)-1)
 205                 printf("%llu", (unsigned long long)end);
 206 }
 207
 208 __attribute__ ((unused))
 209 static void print_range_u32(u32 start, u32 end)
 210 {
 211         if (start)
 212                 printf("%u", start);
 213         printf("..");
 214         if (end != (u32)-1)
 215                 printf("%u", end);
 216 }
 217
 218 static int parse_filters(char *filters, struct btrfs_balance_args *args)
 219 {
 220         char *this_char;
 221         char *value;
 222         char *save_ptr = NULL; /* Satisfy static checkers */
 223
 224         if (!filters)
 225                 return 0;
 226
 227         for (this_char = strtok_r(filters, ",", &save_ptr);
 228              this_char != NULL;
 229              this_char = strtok_r(NULL, ",", &save_ptr)) {
 230                 if ((value = strchr(this_char, '=')) != NULL)
 231                         *value++ = 0;
 232                 if (!strcmp(this_char, "profiles")) {
 233                         if (!value || !*value) {
 234                                 error("the profiles filter requires an argument");
 235                                 return 1;
 236                         }
 237                         if (parse_profiles(value, &args->profiles)) {
 238                                 error("invalid profiles argument");
 239                                 return 1;
 240                         }
 241                         args->flags |= BTRFS_BALANCE_ARGS_PROFILES;
 242                 } else if (!strcmp(this_char, "usage")) {
 243                         if (!value || !*value) {
 244                                 error("the usage filter requires an argument");
 245                                 return 1;
 246                         }
 247                         if (parse_u64(value, &args->usage)) {
 248                                 if (parse_range_u32(value, &args->usage_min,
 249                                                         &args->usage_max)) {
 250                                         error("invalid usage argument: %s",
 251                                                 value);
 252                                         return 1;
 253                                 }
 254                                 if (args->usage_max > 100) {
 255                                         error("invalid usage argument: %s",
 256                                                 value);
 257                                 }
 258                                 args->flags &= ~BTRFS_BALANCE_ARGS_USAGE;
 259                                 args->flags |= BTRFS_BALANCE_ARGS_USAGE_RANGE;
 260                         } else {
 261                                 if (args->usage > 100) {
 262                                         error("invalid usage argument: %s",
 263                                                 value);
 264                                         return 1;
 265                                 }
 266                                 args->flags &= ~BTRFS_BALANCE_ARGS_USAGE_RANGE;
 267                                 args->flags |= BTRFS_BALANCE_ARGS_USAGE;
 268                         }
 269                         args->flags |= BTRFS_BALANCE_ARGS_USAGE;
 270                 } else if (!strcmp(this_char, "devid")) {
 271                         if (!value || !*value) {
 272                                 error("the devid filter requires an argument");
 273                                 return 1;
 274                         }
 275                         if (parse_u64(value, &args->devid) || args->devid == 0) {
 276                                 error("invalid devid argument: %s", value);
 277                                 return 1;
 278                         }
 279                         args->flags |= BTRFS_BALANCE_ARGS_DEVID;
 280                 } else if (!strcmp(this_char, "drange")) {
 281                         if (!value || !*value) {
 282                                 error("the drange filter requires an argument");
 283                                 return 1;
 284                         }
 285                         if (parse_range_strict(value, &args->pstart, &args->pend)) {
 286                                 error("invalid drange argument");
 287                                 return 1;
 288                         }
 289                         args->flags |= BTRFS_BALANCE_ARGS_DRANGE;
 290                 } else if (!strcmp(this_char, "vrange")) {
 291                         if (!value || !*value) {
 292                                 error("the vrange filter requires an argument");
 293                                 return 1;
 294                         }
 295                         if (parse_range_strict(value, &args->vstart, &args->vend)) {
 296                                 error("invalid vrange argument");
 297                                 return 1;
 298                         }
 299                         args->flags |= BTRFS_BALANCE_ARGS_VRANGE;
 300                 } else if (!strcmp(this_char, "convert")) {
 301                         if (!value || !*value) {
 302                                 error("the convert option requires an argument");
 303                                 return 1;
 304                         }
 305                         if (parse_one_profile(value, &args->target)) {
 306                                 error("invalid convert argument");
 307                                 return 1;
 308                         }
 309                         args->flags |= BTRFS_BALANCE_ARGS_CONVERT;
 310                 } else if (!strcmp(this_char, "soft")) {
 311                         args->flags |= BTRFS_BALANCE_ARGS_SOFT;
 312                 } else if (!strcmp(this_char, "limit")) {
 313                         if (!value || !*value) {
 314                                 error("the limit filter requires an argument");
 315                                 return 1;
 316                         }
 317                         if (parse_u64(value, &args->limit)) {
 318                                 if (parse_range_u32(value, &args->limit_min,
 319                                                         &args->limit_max)) {
 320                                         error("Invalid limit argument: %s",
 321                                                value);
 322                                         return 1;
 323                                 }
 324                                 args->flags &= ~BTRFS_BALANCE_ARGS_LIMIT;
 325                                 args->flags |= BTRFS_BALANCE_ARGS_LIMIT_RANGE;
 326                         } else {
 327                                 args->flags &= ~BTRFS_BALANCE_ARGS_LIMIT_RANGE;
 328                                 args->flags |= BTRFS_BALANCE_ARGS_LIMIT;
 329                         }
 330                 } else if (!strcmp(this_char, "stripes")) {
 331                         if (!value || !*value) {
 332                                 error("the stripes filter requires an argument");
 333                                 return 1;
 334                         }
 335                         if (parse_range_u32(value, &args->stripes_min,
 336                                             &args->stripes_max)) {
 337                                 error("invalid stripes argument");
 338                                 return 1;
 339                         }
 340                         args->flags |= BTRFS_BALANCE_ARGS_STRIPES_RANGE;
 341                 } else {
 342                         error("unrecognized balance option: %s", this_char);
 343                         return 1;
 344                 }
 345         }
 346
 347         return 0;
 348 }
 349
 350 static void dump_balance_args(struct btrfs_balance_args *args)
 351 {
 352         if (args->flags & BTRFS_BALANCE_ARGS_CONVERT) {
 353                 printf("converting, target=%llu, soft is %s",
 354                        (unsigned long long)args->target,
 355                        (args->flags & BTRFS_BALANCE_ARGS_SOFT) ? "on" : "off");
 356         } else {
 357                 printf("balancing");
 358         }
 359
 360         if (args->flags & BTRFS_BALANCE_ARGS_PROFILES)
 361                 printf(", profiles=%llu", (unsigned long long)args->profiles);
 362         if (args->flags & BTRFS_BALANCE_ARGS_USAGE)
 363                 printf(", usage=%llu", (unsigned long long)args->usage);
 364         if (args->flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) {
 365                 printf(", usage=");
 366                 print_range_u32(args->usage_min, args->usage_max);
 367         }
 368         if (args->flags & BTRFS_BALANCE_ARGS_DEVID)
 369                 printf(", devid=%llu", (unsigned long long)args->devid);
 370         if (args->flags & BTRFS_BALANCE_ARGS_DRANGE)
 371                 printf(", drange=%llu..%llu",
 372                        (unsigned long long)args->pstart,
 373                        (unsigned long long)args->pend);
 374         if (args->flags & BTRFS_BALANCE_ARGS_VRANGE)
 375                 printf(", vrange=%llu..%llu",
 376                        (unsigned long long)args->vstart,
 377                        (unsigned long long)args->vend);
 378         if (args->flags & BTRFS_BALANCE_ARGS_LIMIT)
 379                 printf(", limit=%llu", (unsigned long long)args->limit);
 380         if (args->flags & BTRFS_BALANCE_ARGS_LIMIT_RANGE) {
 381                 printf(", limit=");
 382                 print_range_u32(args->limit_min, args->limit_max);
 383         }
 384         if (args->flags & BTRFS_BALANCE_ARGS_STRIPES_RANGE) {
 385                 printf(", stripes=");
 386                 print_range_u32(args->stripes_min, args->stripes_max);
 387         }
 388
 389         printf("\n");
 390 }
 391
 392 static void dump_ioctl_balance_args(struct btrfs_ioctl_balance_args *args)
 393 {
 394         printf("Dumping filters: flags 0x%llx, state 0x%llx, force is %s\n",
 395                (unsigned long long)args->flags, (unsigned long long)args->state,
 396                (args->flags & BTRFS_BALANCE_FORCE) ? "on" : "off");
 397         if (args->flags & BTRFS_BALANCE_DATA) {
 398                 printf("  DATA (flags 0x%llx): ",
 399                        (unsigned long long)args->data.flags);
 400                 dump_balance_args(&args->data);
 401         }
 402         if (args->flags & BTRFS_BALANCE_METADATA) {
 403                 printf("  METADATA (flags 0x%llx): ",
 404                        (unsigned long long)args->meta.flags);
 405                 dump_balance_args(&args->meta);
 406         }
 407         if (args->flags & BTRFS_BALANCE_SYSTEM) {
 408                 printf("  SYSTEM (flags 0x%llx): ",
 409                        (unsigned long long)args->sys.flags);
 410                 dump_balance_args(&args->sys);
 411         }
 412 }
 413
 414 static int do_balance_v1(int fd)
 415 {
 416         struct btrfs_ioctl_vol_args args;
 417         int ret;
 418
 419         memset(&args, 0, sizeof(args));
 420         ret = ioctl(fd, BTRFS_IOC_BALANCE, &args);
 421         return ret;
 422 }
 423
 424 enum {
 425         BALANCE_START_FILTERS = 1 << 0,
 426         BALANCE_START_NOWARN  = 1 << 1
 427 };
 428
 429 static int do_balance(const char *path, struct btrfs_ioctl_balance_args *args,
 430                       unsigned flags)
 431 {
 432         int fd;
 433         int ret;
 434         DIR *dirstream = NULL;
 435
 436         fd = btrfs_open_dir(path, &dirstream, 1);
 437         if (fd < 0)
 438                 return 1;
 439
 440         if (!(flags & BALANCE_START_FILTERS) && !(flags & BALANCE_START_NOWARN)) {
 441                 int delay = 10;
 442
 443                 printf("WARNING:\n\n");
 444                 printf("\tFull balance without filters requested. This operation is very\n");
 445                 printf("\tintense and takes potentially very long. It is recommended to\n");
 446                 printf("\tuse the balance filters to narrow down the scope of balance.\n");
 447                 printf("\tUse 'btrfs balance start --full-balance' option to skip this\n");
 448                 printf("\twarning. The operation will start in %d seconds.\n", delay);
 449                 printf("\tUse Ctrl-C to stop it.\n");
 450                 while (delay) {
 451                         printf("%2d", delay--);
 452                         fflush(stdout);
 453                         sleep(1);
 454                 }
 455                 printf("\nStarting balance without any filters.\n");
 456         }
 457
 458         ret = ioctl(fd, BTRFS_IOC_BALANCE_V2, args);
 459         if (ret < 0) {
 460                 /*
 461                  * older kernels don't have the new balance ioctl, try the
 462                  * old one.  But, the old one doesn't know any filters, so
 463                  * don't fall back if they tried to use the fancy new things
 464                  */
 465                 if (errno == ENOTTY && !(flags & BALANCE_START_FILTERS)) {
 466                         ret = do_balance_v1(fd);
 467                         if (ret == 0)
 468                                 goto out;
 469                 }
 470
 471                 if (errno == ECANCELED) {
 472                         if (args->state & BTRFS_BALANCE_STATE_PAUSE_REQ)
 473                                 fprintf(stderr, "balance paused by user\n");
 474                         if (args->state & BTRFS_BALANCE_STATE_CANCEL_REQ)
 475                                 fprintf(stderr, "balance canceled by user\n");
 476                         ret = 0;
 477                 } else {
 478                         error("error during balancing '%s': %m", path);
 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': %m\n"
 797                           "There may be more info in syslog - try dmesg | tail",
 798                                 path);
 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: %m", path);
 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 }