umount: make -d always active, add -D to suppress it

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 16 insertions, 8 deletions

diff --git a/util-linux/umount.c b/util-linux/umount.c
index 5b716c688..4c2e8821e 100644
--- a/util-linux/umount.c
+++ b/util-linux/umount.c
@@ -22,7 +22,7 @@
 //usage:     "\n        -l      Lazy umount (detach filesystem)"
 //usage:     "\n        -f      Force umount (i.e., unreachable NFS server)"
 //usage:        IF_FEATURE_MOUNT_LOOP(
-//usage:     "\n        -d      Free loop device if it has been used"
+//usage:     "\n        -D      Don't free loop device even if it has been used"
 //usage:        )
 //usage:
 //usage:#define umount_example_usage
@@ -44,14 +44,22 @@ static struct mntent *getmntent_r(FILE* stream, struct mntent* result,
 }
 #endif
 
-/* ignored: -v -d -t -i */
-#define OPTION_STRING           "fldnra" "vdt:i"
+/* Ignored: -v -t -i
+ * bbox always acts as if -d is present.
+ * -D can be used to suppress it (bbox extension).
+ * Rationale:
+ * (1) util-linux's umount does it if "loop=..." is seen in /etc/mtab:
+ * thus, on many systems, bare umount _does_ drop loop devices.
+ * (2) many users request this feature.
+ */
+#define OPTION_STRING           "fldDnra" "vt:i"
 #define OPT_FORCE               (1 << 0) // Same as MNT_FORCE
 #define OPT_LAZY                (1 << 1) // Same as MNT_DETACH
-#define OPT_FREELOOP            (1 << 2)
-#define OPT_NO_MTAB             (1 << 3)
-#define OPT_REMOUNT             (1 << 4)
-#define OPT_ALL                 (ENABLE_FEATURE_UMOUNT_ALL ? (1 << 5) : 0)
+//#define OPT_FREE_LOOP           (1 << 2) // -d is assumed always present
+#define OPT_DONT_FREE_LOOP      (1 << 3)
+#define OPT_NO_MTAB             (1 << 4)
+#define OPT_REMOUNT             (1 << 5)
+#define OPT_ALL                 (ENABLE_FEATURE_UMOUNT_ALL ? (1 << 6) : 0)
 
 int umount_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int umount_main(int argc UNUSED_PARAM, char **argv)
@@ -165,7 +173,7 @@ int umount_main(int argc UNUSED_PARAM, char **argv)
                 } else {
                         // De-allocate the loop device.  This ioctl should be ignored on
                         // any non-loop block devices.
-                        if (ENABLE_FEATURE_MOUNT_LOOP && (opt & OPT_FREELOOP) && m)
+                        if (ENABLE_FEATURE_MOUNT_LOOP && !(opt & OPT_DONT_FREE_LOOP) && m)
                                 del_loop(m->device);
                         if (ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m)
                                 erase_mtab(m->dir);