btrfs-progs: add option to run balance as daemon

[platform/upstream/btrfs-progs.git] / cmds-balance.c

diff --git a/cmds-balance.c b/cmds-balance.c
index 374e981..e9e388e 100644 (file)
--- a/cmds-balance.c
+++ b/cmds-balance.c
@@ -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"
@@ -507,6 +510,7 @@ static const char * const cmd_balance_start_usage[] = {
        "-v             be verbose",
        "-f             force reducing of metadata integrity",
        "--full-balance do not print warning and do not delay start",
+       "--background   run the balance as a background process",
        NULL
 };
 
@@ -517,13 +521,15 @@ static int cmd_balance_start(int argc, char **argv)
                                                &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 };
+               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' },
@@ -532,6 +538,8 @@ static int cmd_balance_start(int argc, char **argv)
                        { "verbose", no_argument, NULL, 'v' },
                        { "full-balance", no_argument, NULL,
                                GETOPT_VAL_FULL_BALANCE },
+                       { "background", no_argument, NULL,
+                               GETOPT_VAL_BACKGROUND },
                        { NULL, 0, NULL, 0 }
                };
 
@@ -570,6 +578,9 @@ static int cmd_balance_start(int argc, char **argv)
                case GETOPT_VAL_FULL_BALANCE:
                        start_flags |= BALANCE_START_NOWARN;
                        break;
+               case GETOPT_VAL_BACKGROUND:
+                       background = 1;
+                       break;
                default:
                        usage(cmd_balance_start_usage);
                }
@@ -622,6 +633,35 @@ 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):
+                               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);
 }