sfdisk: add --move-use-fsync, disable fsync() by default

It's slow, so slooow...

Addresses: https://github.com/karelzak/util-linux/issues/848
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/disk-utils/sfdisk.8 b/disk-utils/sfdisk.8
index c572145fb3876adb6d79ecf69cd9fa5fcab51822..f7f39e393f311cf36896fdabea957f0b727d5d2d 100644 (file)
--- a/disk-utils/sfdisk.8
+++ b/disk-utils/sfdisk.8
@@ -217,6 +217,8 @@ optional since v2.35.
 
 Note that this operation is risky and not atomic. \fBDon't forget to backup your data!\fR
 
+See also \fB\-\-move\-use\-fsync\fR.
+
 In the example below, the first command creates a 100MiB free area before
 the first partition and moves the data it contains (e.g. a filesystem),
 the next command creates a new partition from the free space (at offset 2048),
@@ -232,6 +234,10 @@ and the last command reorders partitions to match disk order
 .sp
 .RE
 
+.TP
+.BR \-\-move\-use\-fsync
+Use fsync system call after each write when move dara to a new location by
+\fB\-\-move\-data\fR.
 .TP
 .BR \-o , " \-\-output " \fIlist
 Specify which output columns to print.  Use

diff --git a/disk-utils/sfdisk.c b/disk-utils/sfdisk.c
index e7481aab79dab7fcb4280192cdfe68527719ce4b..cbae88b9a388a7195292754abb093f080aa8eec3 100644 (file)
--- a/disk-utils/sfdisk.c
+++ b/disk-utils/sfdisk.c
@@ -111,6 +111,7 @@ struct sfdisk {
                     append : 1,        /* don't create new PT, append partitions only */
                     json : 1,          /* JSON dump */
                     movedata: 1,       /* move data after resize */
+                    movefsync: 1, /* use fsync() afetr each write() */
                     notell : 1,        /* don't tell kernel aout new PT */
                     noact  : 1;        /* do not write to device */
 };
@@ -515,7 +516,8 @@ static int move_partition_data(struct sfdisk *sf, size_t partno, struct fdisk_pa
                        rc = write(fd, buf, step_bytes);
                        if (rc < 0 || rc != (ssize_t) step_bytes)
                                goto fail;
-                       fsync(fd);
+                       if (sf->movefsync)
+                               fsync(fd);
                }
 
                /* write log */
@@ -1898,6 +1900,7 @@ static void __attribute__((__noreturn__)) usage(void)
        fputs(_(" -b, --backup              backup partition table sectors (see -O)\n"), out);
        fputs(_("     --bytes               print SIZE in bytes rather than in human readable format\n"), out);
        fputs(_("     --move-data[=<typescript>] move partition data after relocation (requires -N)\n"), out);
+       fputs(_("     --move-use-fsync      use fsync after each write when move data\n"), out);
        fputs(_(" -f, --force               disable all consistency checking\n"), out);
        fprintf(out,
              _("     --color[=<when>]      colorize output (%s, %s or %s)\n"), "auto", "always", "never");
@@ -1956,6 +1959,7 @@ int main(int argc, char *argv[])
                OPT_BYTES,
                OPT_COLOR,
                OPT_MOVEDATA,
+               OPT_MOVEFSYNC,
                OPT_DELETE,
                OPT_NOTELL
        };
@@ -1981,6 +1985,7 @@ int main(int argc, char *argv[])
                { "no-reread", no_argument,     NULL, OPT_NOREREAD },
                { "no-tell-kernel", no_argument, NULL, OPT_NOTELL },
                { "move-data", optional_argument, NULL, OPT_MOVEDATA },
+               { "move-use-fsync", no_argument, NULL, OPT_MOVEFSYNC },
                { "output",  required_argument, NULL, 'o' },
                { "partno",  required_argument, NULL, 'N' },
                { "reorder", no_argument,       NULL, 'r' },
@@ -2152,6 +2157,9 @@ int main(int argc, char *argv[])
                        sf->movedata = 1;
                        sf->move_typescript = optarg;
                        break;
+               case OPT_MOVEFSYNC:
+                       sf->movefsync = 1;
+                       break;
                case OPT_DELETE:
                        sf->act = ACT_DELETE;
                        break;