volume_id: ntfs - mark as no other fs must match

2 files changed, 16 insertions, 1 deletions

diff --git a/NEWS b/NEWS
index aec8bb330b..b102ba37a3 100644
--- a/NEWS
+++ b/NEWS
@@ -14,6 +14,20 @@ functionality.
 Installations which support old kernels, but install current default
 udev rules may need to add that to the compat rules file.
 
+Libvolume_id now always probes for all known filesystems, and does not
+stop at the first match. Some filesystems are marked as "exclusive probe"
+and if one of these filesytem types match, libvolume_id will not return
+a probing result if any other filesystem type matches. This is intended
+to help with conflicting left-over signatures from earlier file system
+formats. That way, we no longer depend on the probing order for competing 
+signatures.
+In some cases the kernel allows to mount a volume with the old filesystem
+type, before it has been re-formatted with a different type. This can
+damage the new filesystem and lead to data loss. Because volume_id can
+not decide which is the correct signature, the wrong signatures need to
+be removed manually from the volume, or the volume needs to be reformatted
+to make filesystem auto-detection and possible auto-mounting working.
+
 udev 132
 ========
 
diff --git a/extras/volume_id/lib/ntfs.c b/extras/volume_id/lib/ntfs.c
index f861b4bf28..b322c77dbd 100644
--- a/extras/volume_id/lib/ntfs.c
+++ b/extras/volume_id/lib/ntfs.c
@@ -195,6 +195,7 @@ int volume_id_probe_ntfs(struct volume_id *id, uint64_t off, uint64_t size)
 
 	volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
 	id->type = "ntfs";
-
+	/* we think this is ntfs, but we make sure no other signatures are found */
+	id->force_unique_result = 1;
 	return 0;
 }