btrfs-progs: docs: add section about filesystem limits to btrfs(5)
[platform/upstream/btrfs-progs.git] / cmds-balance.c
index d141b46..0c91bdf 100644 (file)
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <getopt.h>
 #include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #include <errno.h>
 
 #include "kerncompat.h"
 #include "volumes.h"
 
 #include "commands.h"
+#include "utils.h"
+#include "help.h"
 
-static const char balance_cmd_group_usage[] =
-       "btrfs [filesystem] balance [<command>] [options] <path>";
+static const char * const balance_cmd_group_usage[] = {
+       "btrfs balance <command> [options] <path>",
+       "btrfs balance <path>",
+       NULL
+};
 
-static const char balance_cmd_group_info[] =
-       "'btrfs filesystem balance' command is deprecated, please use\n"
-       "'btrfs balance start' command instead.";
+static int parse_one_profile(const char *profile, u64 *flags)
+{
+       if (!strcmp(profile, "raid0")) {
+               *flags |= BTRFS_BLOCK_GROUP_RAID0;
+       } else if (!strcmp(profile, "raid1")) {
+               *flags |= BTRFS_BLOCK_GROUP_RAID1;
+       } else if (!strcmp(profile, "raid10")) {
+               *flags |= BTRFS_BLOCK_GROUP_RAID10;
+       } else if (!strcmp(profile, "raid5")) {
+               *flags |= BTRFS_BLOCK_GROUP_RAID5;
+       } else if (!strcmp(profile, "raid6")) {
+               *flags |= BTRFS_BLOCK_GROUP_RAID6;
+       } else if (!strcmp(profile, "dup")) {
+               *flags |= BTRFS_BLOCK_GROUP_DUP;
+       } else if (!strcmp(profile, "single")) {
+               *flags |= BTRFS_AVAIL_ALLOC_BIT_SINGLE;
+       } else {
+               error("unknown profile: %s", profile);
+               return 1;
+       }
+
+       return 0;
+}
+
+static int parse_profiles(char *profiles, u64 *flags)
+{
+       char *this_char;
+       char *save_ptr = NULL; /* Satisfy static checkers */
+
+       for (this_char = strtok_r(profiles, "|", &save_ptr);
+            this_char != NULL;
+            this_char = strtok_r(NULL, "|", &save_ptr)) {
+               if (parse_one_profile(this_char, flags))
+                       return 1;
+       }
+
+       return 0;
+}
+
+static int parse_u64(const char *str, u64 *result)
+{
+       char *endptr;
+       u64 val;
+
+       val = strtoull(str, &endptr, 10);
+       if (*endptr)
+               return 1;
+
+       *result = val;
+       return 0;
+}
+
+/*
+ * Parse range that's missing some part that can be implicit:
+ * a..b        - exact range, a can be equal to b
+ * a.. - implicitly unbounded maximum (end == (u64)-1)
+ * ..b - implicitly starting at 0
+ * a   - invalid; unclear semantics, use parse_u64 instead
+ *
+ * Returned values are u64, value validation and interpretation should be done
+ * by the caller.
+ */
+static int parse_range(const char *range, u64 *start, u64 *end)
+{
+       char *dots;
+       char *endptr;
+       const char *rest;
+       int skipped = 0;
+
+       dots = strstr(range, "..");
+       if (!dots)
+               return 1;
+
+       rest = dots + 2;
+
+       if (!*rest) {
+               *end = (u64)-1;
+               skipped++;
+       } else {
+               *end = strtoull(rest, &endptr, 10);
+               if (*endptr)
+                       return 1;
+       }
+       if (dots == range) {
+               *start = 0;
+               skipped++;
+       } else {
+               *start = strtoull(range, &endptr, 10);
+               if (*endptr != 0 && *endptr != '.')
+                       return 1;
+       }
+
+       if (*start > *end) {
+               error("range %llu..%llu doesn't make sense",
+                       (unsigned long long)*start,
+                       (unsigned long long)*end);
+               return 1;
+       }
+
+       if (skipped <= 1)
+               return 0;
+
+       return 1;
+}
+
+/*
+ * Parse range and check if start < end
+ */
+static int parse_range_strict(const char *range, u64 *start, u64 *end)
+{
+       if (parse_range(range, start, end) == 0) {
+               if (*start >= *end) {
+                       error("range %llu..%llu not allowed",
+                               (unsigned long long)*start,
+                               (unsigned long long)*end);
+                       return 1;
+               }
+               return 0;
+       }
+
+       return 1;
+}
+
+/*
+ * Convert 64bit range to 32bit with boundary checks
+ */
+static int range_to_u32(u64 start, u64 end, u32 *start32, u32 *end32)
+{
+       if (start > (u32)-1)
+               return 1;
+
+       if (end != (u64)-1 && end > (u32)-1)
+               return 1;
+
+       *start32 = (u32)start;
+       *end32 = (u32)end;
+
+       return 0;
+}
+
+__attribute__ ((unused))
+static int parse_range_u32(const char *range, u32 *start, u32 *end)
+{
+       u64 tmp_start;
+       u64 tmp_end;
+
+       if (parse_range(range, &tmp_start, &tmp_end))
+               return 1;
+
+       if (range_to_u32(tmp_start, tmp_end, start, end))
+               return 1;
+
+       return 0;
+}
+
+__attribute__ ((unused))
+static void print_range(u64 start, u64 end)
+{
+       if (start)
+               printf("%llu", (unsigned long long)start);
+       printf("..");
+       if (end != (u64)-1)
+               printf("%llu", (unsigned long long)end);
+}
+
+__attribute__ ((unused))
+static void print_range_u32(u32 start, u32 end)
+{
+       if (start)
+               printf("%u", start);
+       printf("..");
+       if (end != (u32)-1)
+               printf("%u", end);
+}
+
+static int parse_filters(char *filters, struct btrfs_balance_args *args)
+{
+       char *this_char;
+       char *value;
+       char *save_ptr = NULL; /* Satisfy static checkers */
+
+       if (!filters)
+               return 0;
+
+       for (this_char = strtok_r(filters, ",", &save_ptr);
+            this_char != NULL;
+            this_char = strtok_r(NULL, ",", &save_ptr)) {
+               if ((value = strchr(this_char, '=')) != NULL)
+                       *value++ = 0;
+               if (!strcmp(this_char, "profiles")) {
+                       if (!value || !*value) {
+                               error("the profiles filter requires an argument");
+                               return 1;
+                       }
+                       if (parse_profiles(value, &args->profiles)) {
+                               error("invalid profiles argument");
+                               return 1;
+                       }
+                       args->flags |= BTRFS_BALANCE_ARGS_PROFILES;
+               } else if (!strcmp(this_char, "usage")) {
+                       if (!value || !*value) {
+                               error("the usage filter requires an argument");
+                               return 1;
+                       }
+                       if (parse_u64(value, &args->usage)) {
+                               if (parse_range_u32(value, &args->usage_min,
+                                                       &args->usage_max)) {
+                                       error("invalid usage argument: %s",
+                                               value);
+                                       return 1;
+                               }
+                               if (args->usage_max > 100) {
+                                       error("invalid usage argument: %s",
+                                               value);
+                               }
+                               args->flags &= ~BTRFS_BALANCE_ARGS_USAGE;
+                               args->flags |= BTRFS_BALANCE_ARGS_USAGE_RANGE;
+                       } else {
+                               if (args->usage > 100) {
+                                       error("invalid usage argument: %s",
+                                               value);
+                                       return 1;
+                               }
+                               args->flags &= ~BTRFS_BALANCE_ARGS_USAGE_RANGE;
+                               args->flags |= BTRFS_BALANCE_ARGS_USAGE;
+                       }
+                       args->flags |= BTRFS_BALANCE_ARGS_USAGE;
+               } else if (!strcmp(this_char, "devid")) {
+                       if (!value || !*value) {
+                               error("the devid filter requires an argument");
+                               return 1;
+                       }
+                       if (parse_u64(value, &args->devid) || args->devid == 0) {
+                               error("invalid devid argument: %s", value);
+                               return 1;
+                       }
+                       args->flags |= BTRFS_BALANCE_ARGS_DEVID;
+               } else if (!strcmp(this_char, "drange")) {
+                       if (!value || !*value) {
+                               error("the drange filter requires an argument");
+                               return 1;
+                       }
+                       if (parse_range_strict(value, &args->pstart, &args->pend)) {
+                               error("invalid drange argument");
+                               return 1;
+                       }
+                       args->flags |= BTRFS_BALANCE_ARGS_DRANGE;
+               } else if (!strcmp(this_char, "vrange")) {
+                       if (!value || !*value) {
+                               error("the vrange filter requires an argument");
+                               return 1;
+                       }
+                       if (parse_range_strict(value, &args->vstart, &args->vend)) {
+                               error("invalid vrange argument");
+                               return 1;
+                       }
+                       args->flags |= BTRFS_BALANCE_ARGS_VRANGE;
+               } else if (!strcmp(this_char, "convert")) {
+                       if (!value || !*value) {
+                               error("the convert option requires an argument");
+                               return 1;
+                       }
+                       if (parse_one_profile(value, &args->target)) {
+                               error("invalid convert argument");
+                               return 1;
+                       }
+                       args->flags |= BTRFS_BALANCE_ARGS_CONVERT;
+               } else if (!strcmp(this_char, "soft")) {
+                       args->flags |= BTRFS_BALANCE_ARGS_SOFT;
+               } else if (!strcmp(this_char, "limit")) {
+                       if (!value || !*value) {
+                               error("the limit filter requires an argument");
+                               return 1;
+                       }
+                       if (parse_u64(value, &args->limit)) {
+                               if (parse_range_u32(value, &args->limit_min,
+                                                       &args->limit_max)) {
+                                       error("Invalid limit argument: %s",
+                                              value);
+                                       return 1;
+                               }
+                               args->flags &= ~BTRFS_BALANCE_ARGS_LIMIT;
+                               args->flags |= BTRFS_BALANCE_ARGS_LIMIT_RANGE;
+                       } else {
+                               args->flags &= ~BTRFS_BALANCE_ARGS_LIMIT_RANGE;
+                               args->flags |= BTRFS_BALANCE_ARGS_LIMIT;
+                       }
+               } else if (!strcmp(this_char, "stripes")) {
+                       if (!value || !*value) {
+                               error("the stripes filter requires an argument");
+                               return 1;
+                       }
+                       if (parse_range_u32(value, &args->stripes_min,
+                                           &args->stripes_max)) {
+                               error("invalid stripes argument");
+                               return 1;
+                       }
+                       args->flags |= BTRFS_BALANCE_ARGS_STRIPES_RANGE;
+               } else {
+                       error("unrecognized balance option: %s", this_char);
+                       return 1;
+               }
+       }
+
+       return 0;
+}
+
+static void dump_balance_args(struct btrfs_balance_args *args)
+{
+       if (args->flags & BTRFS_BALANCE_ARGS_CONVERT) {
+               printf("converting, target=%llu, soft is %s",
+                      (unsigned long long)args->target,
+                      (args->flags & BTRFS_BALANCE_ARGS_SOFT) ? "on" : "off");
+       } else {
+               printf("balancing");
+       }
+
+       if (args->flags & BTRFS_BALANCE_ARGS_PROFILES)
+               printf(", profiles=%llu", (unsigned long long)args->profiles);
+       if (args->flags & BTRFS_BALANCE_ARGS_USAGE)
+               printf(", usage=%llu", (unsigned long long)args->usage);
+       if (args->flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) {
+               printf(", usage=");
+               print_range_u32(args->usage_min, args->usage_max);
+       }
+       if (args->flags & BTRFS_BALANCE_ARGS_DEVID)
+               printf(", devid=%llu", (unsigned long long)args->devid);
+       if (args->flags & BTRFS_BALANCE_ARGS_DRANGE)
+               printf(", drange=%llu..%llu",
+                      (unsigned long long)args->pstart,
+                      (unsigned long long)args->pend);
+       if (args->flags & BTRFS_BALANCE_ARGS_VRANGE)
+               printf(", vrange=%llu..%llu",
+                      (unsigned long long)args->vstart,
+                      (unsigned long long)args->vend);
+       if (args->flags & BTRFS_BALANCE_ARGS_LIMIT)
+               printf(", limit=%llu", (unsigned long long)args->limit);
+       if (args->flags & BTRFS_BALANCE_ARGS_LIMIT_RANGE) {
+               printf(", limit=");
+               print_range_u32(args->limit_min, args->limit_max);
+       }
+       if (args->flags & BTRFS_BALANCE_ARGS_STRIPES_RANGE) {
+               printf(", stripes=");
+               print_range_u32(args->stripes_min, args->stripes_max);
+       }
+
+       printf("\n");
+}
+
+static void dump_ioctl_balance_args(struct btrfs_ioctl_balance_args *args)
+{
+       printf("Dumping filters: flags 0x%llx, state 0x%llx, force is %s\n",
+              (unsigned long long)args->flags, (unsigned long long)args->state,
+              (args->flags & BTRFS_BALANCE_FORCE) ? "on" : "off");
+       if (args->flags & BTRFS_BALANCE_DATA) {
+               printf("  DATA (flags 0x%llx): ",
+                      (unsigned long long)args->data.flags);
+               dump_balance_args(&args->data);
+       }
+       if (args->flags & BTRFS_BALANCE_METADATA) {
+               printf("  METADATA (flags 0x%llx): ",
+                      (unsigned long long)args->meta.flags);
+               dump_balance_args(&args->meta);
+       }
+       if (args->flags & BTRFS_BALANCE_SYSTEM) {
+               printf("  SYSTEM (flags 0x%llx): ",
+                      (unsigned long long)args->sys.flags);
+               dump_balance_args(&args->sys);
+       }
+}
+
+static int do_balance_v1(int fd)
+{
+       struct btrfs_ioctl_vol_args args;
+       int ret;
+
+       memset(&args, 0, sizeof(args));
+       ret = ioctl(fd, BTRFS_IOC_BALANCE, &args);
+       return ret;
+}
+
+enum {
+       BALANCE_START_FILTERS = 1 << 0,
+       BALANCE_START_NOWARN  = 1 << 1
+};
 
-static int do_balance(const char *path, struct btrfs_ioctl_balance_args *args)
+static int do_balance(const char *path, struct btrfs_ioctl_balance_args *args,
+                     unsigned flags)
 {
        int fd;
        int ret;
-       int e;
+       DIR *dirstream = NULL;
+
+       fd = btrfs_open_dir(path, &dirstream, 1);
+       if (fd < 0)
+               return 1;
 
-       fd = open_file_or_dir(path);
-       if (fd < 0) {
-               fprintf(stderr, "ERROR: can't access to '%s'\n", path);
-               return 12;
+       if (!(flags & BALANCE_START_FILTERS) && !(flags & BALANCE_START_NOWARN)) {
+               int delay = 10;
+
+               printf("WARNING:\n\n");
+               printf("\tFull balance without filters requested. This operation is very\n");
+               printf("\tintense and takes potentially very long. It is recommended to\n");
+               printf("\tuse the balance filters to narrow down the scope of balance.\n");
+               printf("\tUse 'btrfs balance start --full-balance' option to skip this\n");
+               printf("\twarning. The operation will start in %d seconds.\n", delay);
+               printf("\tUse Ctrl-C to stop it.\n");
+               while (delay) {
+                       printf("%2d", delay--);
+                       fflush(stdout);
+                       sleep(1);
+               }
+               printf("\nStarting balance without any filters.\n");
        }
 
        ret = ioctl(fd, BTRFS_IOC_BALANCE_V2, args);
-       e = errno;
-       close(fd);
-
        if (ret < 0) {
-               if (e == ECANCELED) {
+               /*
+                * older kernels don't have the new balance ioctl, try the
+                * old one.  But, the old one doesn't know any filters, so
+                * don't fall back if they tried to use the fancy new things
+                */
+               if (errno == ENOTTY && !(flags & BALANCE_START_FILTERS)) {
+                       ret = do_balance_v1(fd);
+                       if (ret == 0)
+                               goto out;
+               }
+
+               if (errno == ECANCELED) {
                        if (args->state & BTRFS_BALANCE_STATE_PAUSE_REQ)
                                fprintf(stderr, "balance paused by user\n");
                        if (args->state & BTRFS_BALANCE_STATE_CANCEL_REQ)
                                fprintf(stderr, "balance canceled by user\n");
+                       ret = 0;
                } else {
-                       fprintf(stderr, "ERROR: error during balancing '%s' "
-                               "- %s\n", path, strerror(e));
-                       if (e != EINPROGRESS)
-                               fprintf(stderr, "There may be more info in "
-                                       "syslog - try dmesg | tail\n");
-                       return 19;
+                       error("error during balancing '%s': %m", path);
+                       if (errno != EINPROGRESS)
+                               fprintf(stderr,
+                       "There may be more info in syslog - try dmesg | tail\n");
+                       ret = 1;
                }
        } else {
                printf("Done, had to relocate %llu out of %llu chunks\n",
                       (unsigned long long)args->stat.completed,
                       (unsigned long long)args->stat.considered);
+               ret = 0;
        }
 
-       return 0;
+out:
+       close_file_or_dir(fd, dirstream);
+       return ret;
+}
+
+static const char * const cmd_balance_start_usage[] = {
+       "btrfs balance start [options] <path>",
+       "Balance chunks across the devices",
+       "Balance and/or convert (change allocation profile of) chunks that",
+       "passed all filters in a comma-separated list of filters for a",
+       "particular chunk type.  If filter list is not given balance all",
+       "chunks of that type.  In case none of the -d, -m or -s options is",
+       "given balance all chunks in a filesystem. This is potentially",
+       "long operation and the user is warned before this start, with",
+       "a delay to stop it.",
+       "",
+       "-d[filters]    act on data chunks",
+       "-m[filters]    act on metadata chunks",
+       "-s[filters]    act on system chunks (only under -f)",
+       "-v             be verbose",
+       "-f             force reducing of metadata integrity",
+       "--full-balance do not print warning and do not delay start",
+       "--background|--bg",
+       "               run the balance as a background process",
+       NULL
+};
+
+static int cmd_balance_start(int argc, char **argv)
+{
+       struct btrfs_ioctl_balance_args args;
+       struct btrfs_balance_args *ptrs[] = { &args.data, &args.sys,
+                                               &args.meta, NULL };
+       int force = 0;
+       int verbose = 0;
+       int background = 0;
+       unsigned start_flags = 0;
+       int i;
+
+       memset(&args, 0, sizeof(args));
+
+       while (1) {
+               enum { GETOPT_VAL_FULL_BALANCE = 256,
+                       GETOPT_VAL_BACKGROUND = 257 };
+               static const struct option longopts[] = {
+                       { "data", optional_argument, NULL, 'd'},
+                       { "metadata", optional_argument, NULL, 'm' },
+                       { "system", optional_argument, NULL, 's' },
+                       { "force", no_argument, NULL, 'f' },
+                       { "verbose", no_argument, NULL, 'v' },
+                       { "full-balance", no_argument, NULL,
+                               GETOPT_VAL_FULL_BALANCE },
+                       { "background", no_argument, NULL,
+                               GETOPT_VAL_BACKGROUND },
+                       { "bg", no_argument, NULL, GETOPT_VAL_BACKGROUND },
+                       { NULL, 0, NULL, 0 }
+               };
+
+               int opt = getopt_long(argc, argv, "d::s::m::fv", longopts, NULL);
+               if (opt < 0)
+                       break;
+
+               switch (opt) {
+               case 'd':
+                       start_flags |= BALANCE_START_FILTERS;
+                       args.flags |= BTRFS_BALANCE_DATA;
+
+                       if (parse_filters(optarg, &args.data))
+                               return 1;
+                       break;
+               case 's':
+                       start_flags |= BALANCE_START_FILTERS;
+                       args.flags |= BTRFS_BALANCE_SYSTEM;
+
+                       if (parse_filters(optarg, &args.sys))
+                               return 1;
+                       break;
+               case 'm':
+                       start_flags |= BALANCE_START_FILTERS;
+                       args.flags |= BTRFS_BALANCE_METADATA;
+
+                       if (parse_filters(optarg, &args.meta))
+                               return 1;
+                       break;
+               case 'f':
+                       force = 1;
+                       break;
+               case 'v':
+                       verbose = 1;
+                       break;
+               case GETOPT_VAL_FULL_BALANCE:
+                       start_flags |= BALANCE_START_NOWARN;
+                       break;
+               case GETOPT_VAL_BACKGROUND:
+                       background = 1;
+                       break;
+               default:
+                       usage(cmd_balance_start_usage);
+               }
+       }
+
+       if (check_argc_exact(argc - optind, 1))
+               usage(cmd_balance_start_usage);
+
+       /*
+        * allow -s only under --force, otherwise do with system chunks
+        * the same thing we were ordered to do with meta chunks
+        */
+       if (args.flags & BTRFS_BALANCE_SYSTEM) {
+               if (!force) {
+                       error(
+                           "Refusing to explicitly operate on system chunks.\n"
+                           "Pass --force if you really want to do that.");
+                       return 1;
+               }
+       } else if (args.flags & BTRFS_BALANCE_METADATA) {
+               args.flags |= BTRFS_BALANCE_SYSTEM;
+               memcpy(&args.sys, &args.meta,
+                       sizeof(struct btrfs_balance_args));
+       }
+
+       if (!(start_flags & BALANCE_START_FILTERS)) {
+               /* relocate everything - no filters */
+               args.flags |= BTRFS_BALANCE_TYPE_MASK;
+       }
+
+       /* drange makes sense only when devid is set */
+       for (i = 0; ptrs[i]; i++) {
+               if ((ptrs[i]->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
+                   !(ptrs[i]->flags & BTRFS_BALANCE_ARGS_DEVID)) {
+                       error("drange filter must be used with devid filter");
+                       return 1;
+               }
+       }
+
+       /* soft makes sense only when convert for corresponding type is set */
+       for (i = 0; ptrs[i]; i++) {
+               if ((ptrs[i]->flags & BTRFS_BALANCE_ARGS_SOFT) &&
+                   !(ptrs[i]->flags & BTRFS_BALANCE_ARGS_CONVERT)) {
+                       error("'soft' option can be used only when converting profiles");
+                       return 1;
+               }
+       }
+
+       if (force)
+               args.flags |= BTRFS_BALANCE_FORCE;
+       if (verbose)
+               dump_ioctl_balance_args(&args);
+       if (background) {
+               switch (fork()) {
+               case (-1):
+                       error("unable to fork to run balance in background");
+                       return 1;
+               case (0):
+                       setsid();
+                       switch(fork()) {
+                       case (-1):
+                               error(
+                               "unable to fork to run balance in background");
+                               exit(1);
+                       case (0):
+                               /*
+                                * Read the return value to silence compiler
+                                * warning. Change to / should succeed and
+                                * we're not in a security-sensitive context.
+                                */
+                               i = chdir("/");
+                               close(0);
+                               close(1);
+                               close(2);
+                               open("/dev/null", O_RDONLY);
+                               open("/dev/null", O_WRONLY);
+                               open("/dev/null", O_WRONLY);
+                               break;
+                       default:
+                               exit(0);
+                       }
+                       break;
+               default:
+                       exit(0);
+               }
+       }
+
+       return do_balance(argv[optind], &args, start_flags);
+}
+
+static const char * const cmd_balance_pause_usage[] = {
+       "btrfs balance pause <path>",
+       "Pause running balance",
+       NULL
+};
+
+static int cmd_balance_pause(int argc, char **argv)
+{
+       const char *path;
+       int fd;
+       int ret;
+       DIR *dirstream = NULL;
+
+       clean_args_no_options(argc, argv, cmd_balance_pause_usage);
+
+       if (check_argc_exact(argc - optind, 1))
+               usage(cmd_balance_pause_usage);
+
+       path = argv[optind];
+
+       fd = btrfs_open_dir(path, &dirstream, 1);
+       if (fd < 0)
+               return 1;
+
+       ret = ioctl(fd, BTRFS_IOC_BALANCE_CTL, BTRFS_BALANCE_CTL_PAUSE);
+       if (ret < 0) {
+               error("balance pause on '%s' failed: %s", path,
+                       (errno == ENOTCONN) ? "Not running" : strerror(errno));
+               if (errno == ENOTCONN)
+                       ret = 2;
+               else
+                       ret = 1;
+       }
+
+       close_file_or_dir(fd, dirstream);
+       return ret;
+}
+
+static const char * const cmd_balance_cancel_usage[] = {
+       "btrfs balance cancel <path>",
+       "Cancel running or paused balance",
+       NULL
+};
+
+static int cmd_balance_cancel(int argc, char **argv)
+{
+       const char *path;
+       int fd;
+       int ret;
+       DIR *dirstream = NULL;
+
+       clean_args_no_options(argc, argv, cmd_balance_cancel_usage);
+
+       if (check_argc_exact(argc - optind, 1))
+               usage(cmd_balance_cancel_usage);
+
+       path = argv[optind];
+
+       fd = btrfs_open_dir(path, &dirstream, 1);
+       if (fd < 0)
+               return 1;
+
+       ret = ioctl(fd, BTRFS_IOC_BALANCE_CTL, BTRFS_BALANCE_CTL_CANCEL);
+       if (ret < 0) {
+               error("balance cancel on '%s' failed: %s", path,
+                       (errno == ENOTCONN) ? "Not in progress" : strerror(errno));
+               if (errno == ENOTCONN)
+                       ret = 2;
+               else
+                       ret = 1;
+       }
+
+       close_file_or_dir(fd, dirstream);
+       return ret;
+}
+
+static const char * const cmd_balance_resume_usage[] = {
+       "btrfs balance resume <path>",
+       "Resume interrupted balance",
+       NULL
+};
+
+static int cmd_balance_resume(int argc, char **argv)
+{
+       struct btrfs_ioctl_balance_args args;
+       const char *path;
+       DIR *dirstream = NULL;
+       int fd;
+       int ret;
+
+       clean_args_no_options(argc, argv, cmd_balance_resume_usage);
+
+       if (check_argc_exact(argc - optind, 1))
+               usage(cmd_balance_resume_usage);
+
+       path = argv[optind];
+
+       fd = btrfs_open_dir(path, &dirstream, 1);
+       if (fd < 0)
+               return 1;
+
+       memset(&args, 0, sizeof(args));
+       args.flags |= BTRFS_BALANCE_RESUME;
+
+       ret = ioctl(fd, BTRFS_IOC_BALANCE_V2, &args);
+       if (ret < 0) {
+               if (errno == ECANCELED) {
+                       if (args.state & BTRFS_BALANCE_STATE_PAUSE_REQ)
+                               fprintf(stderr, "balance paused by user\n");
+                       if (args.state & BTRFS_BALANCE_STATE_CANCEL_REQ)
+                               fprintf(stderr, "balance canceled by user\n");
+               } else if (errno == ENOTCONN || errno == EINPROGRESS) {
+                       error("balance resume on '%s' failed: %s", path,
+                               (errno == ENOTCONN) ? "Not in progress" :
+                                                 "Already running");
+                       if (errno == ENOTCONN)
+                               ret = 2;
+                       else
+                               ret = 1;
+               } else {
+                       error("error during balancing '%s': %m\n"
+                         "There may be more info in syslog - try dmesg | tail",
+                               path);
+                       ret = 1;
+               }
+       } else {
+               printf("Done, had to relocate %llu out of %llu chunks\n",
+                      (unsigned long long)args.stat.completed,
+                      (unsigned long long)args.stat.considered);
+       }
+
+       close_file_or_dir(fd, dirstream);
+       return ret;
+}
+
+static const char * const cmd_balance_status_usage[] = {
+       "btrfs balance status [-v] <path>",
+       "Show status of running or paused balance",
+       "",
+       "-v     be verbose",
+       NULL
+};
+
+/* Checks the status of the balance if any
+ * return codes:
+ *   2 : Error failed to know if there is any pending balance
+ *   1 : Successful to know status of a pending balance
+ *   0 : When there is no pending balance or completed
+ */
+static int cmd_balance_status(int argc, char **argv)
+{
+       struct btrfs_ioctl_balance_args args;
+       const char *path;
+       DIR *dirstream = NULL;
+       int fd;
+       int verbose = 0;
+       int ret;
+
+       while (1) {
+               int opt;
+               static const struct option longopts[] = {
+                       { "verbose", no_argument, NULL, 'v' },
+                       { NULL, 0, NULL, 0 }
+               };
+
+               opt = getopt_long(argc, argv, "v", longopts, NULL);
+               if (opt < 0)
+                       break;
+
+               switch (opt) {
+               case 'v':
+                       verbose = 1;
+                       break;
+               default:
+                       usage(cmd_balance_status_usage);
+               }
+       }
+
+       if (check_argc_exact(argc - optind, 1))
+               usage(cmd_balance_status_usage);
+
+       path = argv[optind];
+
+       fd = btrfs_open_dir(path, &dirstream, 1);
+       if (fd < 0)
+               return 2;
+
+       ret = ioctl(fd, BTRFS_IOC_BALANCE_PROGRESS, &args);
+       if (ret < 0) {
+               if (errno == ENOTCONN) {
+                       printf("No balance found on '%s'\n", path);
+                       ret = 0;
+                       goto out;
+               }
+               error("balance status on '%s' failed: %m", path);
+               ret = 2;
+               goto out;
+       }
+
+       if (args.state & BTRFS_BALANCE_STATE_RUNNING) {
+               printf("Balance on '%s' is running", path);
+               if (args.state & BTRFS_BALANCE_STATE_CANCEL_REQ)
+                       printf(", cancel requested\n");
+               else if (args.state & BTRFS_BALANCE_STATE_PAUSE_REQ)
+                       printf(", pause requested\n");
+               else
+                       printf("\n");
+       } else {
+               printf("Balance on '%s' is paused\n", path);
+       }
+
+       printf("%llu out of about %llu chunks balanced (%llu considered), "
+              "%3.f%% left\n", (unsigned long long)args.stat.completed,
+              (unsigned long long)args.stat.expected,
+              (unsigned long long)args.stat.considered,
+              100 * (1 - (float)args.stat.completed/args.stat.expected));
+
+       if (verbose)
+               dump_ioctl_balance_args(&args);
+
+       ret = 1;
+out:
+       close_file_or_dir(fd, dirstream);
+       return ret;
 }
 
+static int cmd_balance_full(int argc, char **argv)
+{
+       struct btrfs_ioctl_balance_args args;
+
+       memset(&args, 0, sizeof(args));
+       args.flags |= BTRFS_BALANCE_TYPE_MASK;
+
+       return do_balance(argv[1], &args, BALANCE_START_NOWARN);
+}
+
+static const char balance_cmd_group_info[] =
+"balance data across devices, or change block groups using filters";
+
 const struct cmd_group balance_cmd_group = {
        balance_cmd_group_usage, balance_cmd_group_info, {
-               { 0, 0, 0, 0, 0 }
+               { "start", cmd_balance_start, cmd_balance_start_usage, NULL, 0 },
+               { "pause", cmd_balance_pause, cmd_balance_pause_usage, NULL, 0 },
+               { "cancel", cmd_balance_cancel, cmd_balance_cancel_usage, NULL, 0 },
+               { "resume", cmd_balance_resume, cmd_balance_resume_usage, NULL, 0 },
+               { "status", cmd_balance_status, cmd_balance_status_usage, NULL, 0 },
+               { "--full-balance", cmd_balance_full, NULL, NULL, 1 },
+               NULL_CMD_STRUCT
        }
 };
 
 int cmd_balance(int argc, char **argv)
 {
-       if (argc == 2) {
+       if (argc == 2 && strcmp("start", argv[1]) != 0) {
                /* old 'btrfs filesystem balance <path>' syntax */
                struct btrfs_ioctl_balance_args args;
 
                memset(&args, 0, sizeof(args));
                args.flags |= BTRFS_BALANCE_TYPE_MASK;
 
-               return do_balance(argv[1], &args);
+               return do_balance(argv[1], &args, 0);
        }
 
        return handle_command_group(&balance_cmd_group, argc, argv);