packaging: Enable LTO and set visibility to hidden
[platform/upstream/btrfs-progs.git] / cmds-balance.c
index 41c475b..0c91bdf 100644 (file)
@@ -20,6 +20,9 @@
 #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"
@@ -29,6 +32,7 @@
 
 #include "commands.h"
 #include "utils.h"
+#include "help.h"
 
 static const char * const balance_cmd_group_usage[] = {
        "btrfs balance <command> [options] <path>",
@@ -53,7 +57,7 @@ static int parse_one_profile(const char *profile, u64 *flags)
        } else if (!strcmp(profile, "single")) {
                *flags |= BTRFS_AVAIL_ALLOC_BIT_SINGLE;
        } else {
-               fprintf(stderr, "Unknown profile '%s'\n", profile);
+               error("unknown profile: %s", profile);
                return 1;
        }
 
@@ -129,8 +133,7 @@ static int parse_range(const char *range, u64 *start, u64 *end)
        }
 
        if (*start > *end) {
-               fprintf(stderr,
-                       "ERROR: range %llu..%llu doesn't make sense\n",
+               error("range %llu..%llu doesn't make sense",
                        (unsigned long long)*start,
                        (unsigned long long)*end);
                return 1;
@@ -149,8 +152,7 @@ static int parse_range_strict(const char *range, u64 *start, u64 *end)
 {
        if (parse_range(range, start, end) == 0) {
                if (*start >= *end) {
-                       fprintf(stderr,
-                               "ERROR: range %llu..%llu not allowed\n",
+                       error("range %llu..%llu not allowed",
                                (unsigned long long)*start,
                                (unsigned long long)*end);
                        return 1;
@@ -162,7 +164,7 @@ static int parse_range_strict(const char *range, u64 *start, u64 *end)
 }
 
 /*
- * Convert 64bit range to 32bit with boundary checkso
+ * Convert 64bit range to 32bit with boundary checks
  */
 static int range_to_u32(u64 start, u64 end, u32 *start32, u32 *end32)
 {
@@ -229,40 +231,35 @@ static int parse_filters(char *filters, struct btrfs_balance_args *args)
                        *value++ = 0;
                if (!strcmp(this_char, "profiles")) {
                        if (!value || !*value) {
-                               fprintf(stderr, "the profiles filter requires "
-                                      "an argument\n");
+                               error("the profiles filter requires an argument");
                                return 1;
                        }
                        if (parse_profiles(value, &args->profiles)) {
-                               fprintf(stderr, "Invalid profiles argument\n");
+                               error("invalid profiles argument");
                                return 1;
                        }
                        args->flags |= BTRFS_BALANCE_ARGS_PROFILES;
                } else if (!strcmp(this_char, "usage")) {
                        if (!value || !*value) {
-                               fprintf(stderr, "the usage filter requires "
-                                      "an argument\n");
+                               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)) {
-                                       fprintf(stderr,
-                                               "Invalid usage argument: %s\n",
+                                       error("invalid usage argument: %s",
                                                value);
                                        return 1;
                                }
                                if (args->usage_max > 100) {
-                                       fprintf(stderr,
-                                               "Invalid usage argument: %s\n",
+                                       error("invalid usage argument: %s",
                                                value);
                                }
                                args->flags &= ~BTRFS_BALANCE_ARGS_USAGE;
                                args->flags |= BTRFS_BALANCE_ARGS_USAGE_RANGE;
                        } else {
                                if (args->usage > 100) {
-                                       fprintf(stderr,
-                                               "Invalid usage argument: %s\n",
+                                       error("invalid usage argument: %s",
                                                value);
                                        return 1;
                                }
@@ -272,47 +269,41 @@ static int parse_filters(char *filters, struct btrfs_balance_args *args)
                        args->flags |= BTRFS_BALANCE_ARGS_USAGE;
                } else if (!strcmp(this_char, "devid")) {
                        if (!value || !*value) {
-                               fprintf(stderr, "the devid filter requires "
-                                      "an argument\n");
+                               error("the devid filter requires an argument");
                                return 1;
                        }
-                       if (parse_u64(value, &args->devid) ||
-                           args->devid == 0) {
-                               fprintf(stderr, "Invalid devid argument: %s\n",
-                                      value);
+                       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) {
-                               fprintf(stderr, "the drange filter requires "
-                                      "an argument\n");
+                               error("the drange filter requires an argument");
                                return 1;
                        }
                        if (parse_range_strict(value, &args->pstart, &args->pend)) {
-                               fprintf(stderr, "Invalid drange argument\n");
+                               error("invalid drange argument");
                                return 1;
                        }
                        args->flags |= BTRFS_BALANCE_ARGS_DRANGE;
                } else if (!strcmp(this_char, "vrange")) {
                        if (!value || !*value) {
-                               fprintf(stderr, "the vrange filter requires "
-                                      "an argument\n");
+                               error("the vrange filter requires an argument");
                                return 1;
                        }
                        if (parse_range_strict(value, &args->vstart, &args->vend)) {
-                               fprintf(stderr, "Invalid vrange argument\n");
+                               error("invalid vrange argument");
                                return 1;
                        }
                        args->flags |= BTRFS_BALANCE_ARGS_VRANGE;
                } else if (!strcmp(this_char, "convert")) {
                        if (!value || !*value) {
-                               fprintf(stderr, "the convert option requires "
-                                      "an argument\n");
+                               error("the convert option requires an argument");
                                return 1;
                        }
                        if (parse_one_profile(value, &args->target)) {
-                               fprintf(stderr, "Invalid convert argument\n");
+                               error("invalid convert argument");
                                return 1;
                        }
                        args->flags |= BTRFS_BALANCE_ARGS_CONVERT;
@@ -320,15 +311,13 @@ static int parse_filters(char *filters, struct btrfs_balance_args *args)
                        args->flags |= BTRFS_BALANCE_ARGS_SOFT;
                } else if (!strcmp(this_char, "limit")) {
                        if (!value || !*value) {
-                               fprintf(stderr,
-                                       "the limit filter requires an argument\n");
+                               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)) {
-                                       fprintf(stderr,
-                                               "Invalid limit argument: %s\n",
+                                       error("Invalid limit argument: %s",
                                               value);
                                        return 1;
                                }
@@ -340,19 +329,17 @@ static int parse_filters(char *filters, struct btrfs_balance_args *args)
                        }
                } else if (!strcmp(this_char, "stripes")) {
                        if (!value || !*value) {
-                               fprintf(stderr,
-                                       "the stripes filter requires an argument\n");
+                               error("the stripes filter requires an argument");
                                return 1;
                        }
                        if (parse_range_u32(value, &args->stripes_min,
                                            &args->stripes_max)) {
-                               fprintf(stderr, "Invalid stripes argument\n");
+                               error("invalid stripes argument");
                                return 1;
                        }
                        args->flags |= BTRFS_BALANCE_ARGS_STRIPES_RANGE;
                } else {
-                       fprintf(stderr, "Unrecognized balance option '%s'\n",
-                               this_char);
+                       error("unrecognized balance option: %s", this_char);
                        return 1;
                }
        }
@@ -434,46 +421,64 @@ static int do_balance_v1(int fd)
        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,
-                     int nofilters)
+                     unsigned flags)
 {
        int fd;
        int ret;
-       int e;
        DIR *dirstream = NULL;
 
        fd = btrfs_open_dir(path, &dirstream, 1);
        if (fd < 0)
                return 1;
 
-       ret = ioctl(fd, BTRFS_IOC_BALANCE_V2, args);
-       e = errno;
+       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);
        if (ret < 0) {
                /*
                 * 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 (e == ENOTTY && nofilters) {
+               if (errno == ENOTTY && !(flags & BALANCE_START_FILTERS)) {
                        ret = do_balance_v1(fd);
                        if (ret == 0)
                                goto out;
-                       e = errno;
                }
 
-               if (e == ECANCELED) {
+               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");
+                       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 {
@@ -495,13 +500,18 @@ static const char * const cmd_balance_start_usage[] = {
        "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.",
+       "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
 };
 
@@ -512,19 +522,26 @@ static int cmd_balance_start(int argc, char **argv)
                                                &args.meta, NULL };
        int force = 0;
        int verbose = 0;
-       int nofilters = 1;
+       int background = 0;
+       unsigned start_flags = 0;
        int i;
 
        memset(&args, 0, sizeof(args));
 
-       optind = 1;
        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 }
                };
 
@@ -534,21 +551,21 @@ static int cmd_balance_start(int argc, char **argv)
 
                switch (opt) {
                case 'd':
-                       nofilters = 0;
+                       start_flags |= BALANCE_START_FILTERS;
                        args.flags |= BTRFS_BALANCE_DATA;
 
                        if (parse_filters(optarg, &args.data))
                                return 1;
                        break;
                case 's':
-                       nofilters = 0;
+                       start_flags |= BALANCE_START_FILTERS;
                        args.flags |= BTRFS_BALANCE_SYSTEM;
 
                        if (parse_filters(optarg, &args.sys))
                                return 1;
                        break;
                case 'm':
-                       nofilters = 0;
+                       start_flags |= BALANCE_START_FILTERS;
                        args.flags |= BTRFS_BALANCE_METADATA;
 
                        if (parse_filters(optarg, &args.meta))
@@ -560,6 +577,12 @@ static int cmd_balance_start(int argc, char **argv)
                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);
                }
@@ -574,9 +597,9 @@ static int cmd_balance_start(int argc, char **argv)
         */
        if (args.flags & BTRFS_BALANCE_SYSTEM) {
                if (!force) {
-                       fprintf(stderr,
-"Refusing to explicitly operate on system chunks.\n"
-"Pass --force if you really want to do that.\n");
+                       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) {
@@ -585,7 +608,7 @@ static int cmd_balance_start(int argc, char **argv)
                        sizeof(struct btrfs_balance_args));
        }
 
-       if (nofilters) {
+       if (!(start_flags & BALANCE_START_FILTERS)) {
                /* relocate everything - no filters */
                args.flags |= BTRFS_BALANCE_TYPE_MASK;
        }
@@ -594,8 +617,7 @@ static int cmd_balance_start(int argc, char **argv)
        for (i = 0; ptrs[i]; i++) {
                if ((ptrs[i]->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
                    !(ptrs[i]->flags & BTRFS_BALANCE_ARGS_DEVID)) {
-                       fprintf(stderr, "drange filter can be used only if "
-                               "devid filter is used\n");
+                       error("drange filter must be used with devid filter");
                        return 1;
                }
        }
@@ -604,8 +626,7 @@ static int cmd_balance_start(int argc, char **argv)
        for (i = 0; ptrs[i]; i++) {
                if ((ptrs[i]->flags & BTRFS_BALANCE_ARGS_SOFT) &&
                    !(ptrs[i]->flags & BTRFS_BALANCE_ARGS_CONVERT)) {
-                       fprintf(stderr, "'soft' option can be used only if "
-                               "changing profiles\n");
+                       error("'soft' option can be used only when converting profiles");
                        return 1;
                }
        }
@@ -614,8 +635,42 @@ static int cmd_balance_start(int argc, char **argv)
                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, nofilters);
+       return do_balance(argv[optind], &args, start_flags);
 }
 
 static const char * const cmd_balance_pause_usage[] = {
@@ -629,32 +684,31 @@ static int cmd_balance_pause(int argc, char **argv)
        const char *path;
        int fd;
        int ret;
-       int e;
        DIR *dirstream = NULL;
 
-       if (check_argc_exact(argc, 2))
+       clean_args_no_options(argc, argv, cmd_balance_pause_usage);
+
+       if (check_argc_exact(argc - optind, 1))
                usage(cmd_balance_pause_usage);
 
-       path = argv[1];
+       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);
-       e = errno;
-       close_file_or_dir(fd, dirstream);
-
        if (ret < 0) {
-               fprintf(stderr, "ERROR: balance pause on '%s' failed - %s\n",
-                       path, (e == ENOTCONN) ? "Not running" : strerror(e));
-               if (e == ENOTCONN)
-                       return 2;
+               error("balance pause on '%s' failed: %s", path,
+                       (errno == ENOTCONN) ? "Not running" : strerror(errno));
+               if (errno == ENOTCONN)
+                       ret = 2;
                else
-                       return 1;
+                       ret = 1;
        }
 
-       return 0;
+       close_file_or_dir(fd, dirstream);
+       return ret;
 }
 
 static const char * const cmd_balance_cancel_usage[] = {
@@ -668,32 +722,31 @@ static int cmd_balance_cancel(int argc, char **argv)
        const char *path;
        int fd;
        int ret;
-       int e;
        DIR *dirstream = NULL;
 
-       if (check_argc_exact(argc, 2))
+       clean_args_no_options(argc, argv, cmd_balance_cancel_usage);
+
+       if (check_argc_exact(argc - optind, 1))
                usage(cmd_balance_cancel_usage);
 
-       path = argv[1];
+       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);
-       e = errno;
-       close_file_or_dir(fd, dirstream);
-
        if (ret < 0) {
-               fprintf(stderr, "ERROR: balance cancel on '%s' failed - %s\n",
-                       path, (e == ENOTCONN) ? "Not in progress" : strerror(e));
-               if (e == ENOTCONN)
-                       return 2;
+               error("balance cancel on '%s' failed: %s", path,
+                       (errno == ENOTCONN) ? "Not in progress" : strerror(errno));
+               if (errno == ENOTCONN)
+                       ret = 2;
                else
-                       return 1;
+                       ret = 1;
        }
 
-       return 0;
+       close_file_or_dir(fd, dirstream);
+       return ret;
 }
 
 static const char * const cmd_balance_resume_usage[] = {
@@ -709,12 +762,13 @@ static int cmd_balance_resume(int argc, char **argv)
        DIR *dirstream = NULL;
        int fd;
        int ret;
-       int e;
 
-       if (check_argc_exact(argc, 2))
+       clean_args_no_options(argc, argv, cmd_balance_resume_usage);
+
+       if (check_argc_exact(argc - optind, 1))
                usage(cmd_balance_resume_usage);
 
-       path = argv[1];
+       path = argv[optind];
 
        fd = btrfs_open_dir(path, &dirstream, 1);
        if (fd < 0)
@@ -724,29 +778,25 @@ static int cmd_balance_resume(int argc, char **argv)
        args.flags |= BTRFS_BALANCE_RESUME;
 
        ret = ioctl(fd, BTRFS_IOC_BALANCE_V2, &args);
-       e = errno;
-       close_file_or_dir(fd, dirstream);
-
        if (ret < 0) {
-               if (e == ECANCELED) {
+               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 (e == ENOTCONN || e == EINPROGRESS) {
-                       fprintf(stderr, "ERROR: balance resume on '%s' "
-                               "failed - %s\n", path,
-                               (e == ENOTCONN) ? "Not in progress" :
+               } else if (errno == ENOTCONN || errno == EINPROGRESS) {
+                       error("balance resume on '%s' failed: %s", path,
+                               (errno == ENOTCONN) ? "Not in progress" :
                                                  "Already running");
-                       if (e == ENOTCONN)
-                               return 2;
+                       if (errno == ENOTCONN)
+                               ret = 2;
                        else
-                               return 1;
+                               ret = 1;
                } else {
-                       fprintf(stderr,
-"ERROR: error during balancing '%s' - %s\n"
-"There may be more info in syslog - try dmesg | tail\n", path, strerror(e));
-                       return 1;
+                       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",
@@ -754,7 +804,8 @@ static int cmd_balance_resume(int argc, char **argv)
                       (unsigned long long)args.stat.considered);
        }
 
-       return 0;
+       close_file_or_dir(fd, dirstream);
+       return ret;
 }
 
 static const char * const cmd_balance_status_usage[] = {
@@ -779,9 +830,7 @@ static int cmd_balance_status(int argc, char **argv)
        int fd;
        int verbose = 0;
        int ret;
-       int e;
 
-       optind = 1;
        while (1) {
                int opt;
                static const struct option longopts[] = {
@@ -812,17 +861,15 @@ static int cmd_balance_status(int argc, char **argv)
                return 2;
 
        ret = ioctl(fd, BTRFS_IOC_BALANCE_PROGRESS, &args);
-       e = errno;
-       close_file_or_dir(fd, dirstream);
-
        if (ret < 0) {
-               if (e == ENOTCONN) {
+               if (errno == ENOTCONN) {
                        printf("No balance found on '%s'\n", path);
-                       return 0;
+                       ret = 0;
+                       goto out;
                }
-               fprintf(stderr, "ERROR: balance status on '%s' failed - %s\n",
-                       path, strerror(e));
-               return 2;
+               error("balance status on '%s' failed: %m", path);
+               ret = 2;
+               goto out;
        }
 
        if (args.state & BTRFS_BALANCE_STATE_RUNNING) {
@@ -846,11 +893,24 @@ static int cmd_balance_status(int argc, char **argv)
        if (verbose)
                dump_ioctl_balance_args(&args);
 
-       return 1;
+       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 accross devices, or change block groups using filters";
+"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, {
@@ -859,20 +919,21 @@ const struct cmd_group balance_cmd_group = {
                { "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, 1);
+               return do_balance(argv[1], &args, 0);
        }
 
        return handle_command_group(&balance_cmd_group, argc, argv);