makefs: fix too-long swap labels

Apparently mkswap has it's own limit, and it seems to be one lower than the one
for ext2/3/4.

$ for i in ext2 ext3 ext4 btrfs xfs vfat swap minix; do
  echo $i && wipefs -q -a '/var/tmp/głąbźśńćąśððð.img'
  build/systemd-makefs $i '/var/tmp/głąbźśńćąśððð.img'
done

ext2
/var/tmp/głąbźśńćąśððð.img successfully formatted as ext2 (label "głąbźśńćą", uuid 7626bc5c-8ac4-43cf-87b7-1b2761272dd3)
ext3
/var/tmp/głąbźśńćąśððð.img successfully formatted as ext3 (label "głąbźśńćą", uuid 0da22cad-0dbf-4a7a-962d-12cd39d006b5)
ext4
/var/tmp/głąbźśńćąśððð.img successfully formatted as ext4 (label "głąbźśńćą", uuid dded267b-8955-4d19-82a5-1f231d446059)
btrfs
/var/tmp/głąbźśńćąśððð.img successfully formatted as btrfs (label "głąbźśńćąśððð.img", uuid 9e2e89f1-010d-4ab6-80f3-f9e215dbc225)
xfs
/var/tmp/głąbźśńćąśððð.img successfully formatted as xfs (label "głąbźśń", uuid 2cc937af-4c41-465c-8f52-aab2304bd860)
vfat
mkfs.fat 4.2 (2021-01-31)
/var/tmp/głąbźśńćąśððð.img successfully formatted as vfat (label "G__B_______", uuid a3a9e028)

swap
...
LABEL=głąbźśńć, UUID=0ab787aa-37a6-4b32-978b-d71efc6e6098
/var/tmp/głąbźśńćąśððð.img successfully formatted as swap (label "głąbźśńć", uuid 0ab787aa-37a6-4b32-978b-d71efc6e6098)

minix
...
/var/tmp/głąbźśńćąśððð.img successfully formatted as minix (no label or uuid specified)

diff --git a/src/shared/mkfs-util.c b/src/shared/mkfs-util.c
index f67d7475a0b60308d6c558d624bc229bd04c00dc..de03cd3c7d2d960c3fc2d059a9d27230db24f29b 100644 (file)
--- a/src/shared/mkfs-util.c
+++ b/src/shared/mkfs-util.c
@@ -119,10 +119,15 @@ int make_filesystem(
                         return log_oom();
         }
 
-        if (STR_IN_SET(fstype, "ext2", "ext3", "ext4", "xfs")) {
-                r = mangle_linux_fs_label(label, streq(fstype, "xfs") ? 12 : 16, &mangled_label);
+        if (STR_IN_SET(fstype, "ext2", "ext3", "ext4", "xfs", "swap")) {
+                size_t max_len =
+                        streq(fstype, "xfs") ? 12 :
+                        streq(fstype, "swap") ? 15 :
+                        16;
+
+                r = mangle_linux_fs_label(label, max_len, &mangled_label);
                 if (r < 0)
-                        return log_error_errno(r, "Failed to determine fs label from string \"%s\": %m", label);
+                        return log_error_errno(r, "Failed to determine volume label from string \"%s\": %m", label);
                 label = mangled_label;
 
         } else if (streq(fstype, "vfat")) {