mkfs-util: Set sector size for btrfs as well

btrfs used to default the sector size to the page size and didn't
support anything else. Since 6.7, it defaults to 4K and using 4K
makes the filesystem compatible with all page sizes. So let's make
sure we use minimum 4K as well (lower causes failures on systems with
a 4K page size) but still allow larger sector sizes if specified by
the user.

src/shared/mkfs-util.c

@@ -461,6 +461,15 @@ int make_filesystem(
                 if (quiet)
                         stdio_fds[1] = -EBADF;
 
+                if (sector_size > 0) {
+                        if (strv_extend(&argv, "--sectorsize") < 0)
+                                return log_oom();
+
+                        /* mkfs.btrfs expects a sector size of at least 4k bytes. */
+                        if (strv_extendf(&argv, "%"PRIu64, MAX(sector_size, 4 * U64_KB)) < 0)
+                                return log_oom();
+                }
+
         } else if (streq(fstype, "f2fs")) {
                 argv = strv_new(mkfs,
                                 "-g",  /* "default options" */