udev-extraconf/mount.sh: only mount devices on hotplug

fdisk from util-linux (2.31.1) and above allows the user to
manipulate an already mounted device. In order to achieve this
functionality it issues a BLKRRPART (block device re-read part)
ioctl and in response the kernel generates remove/change/add
events if the device is not mounted (manually unmounted etc)
which are caught and processed by udev. This causes our auto-mounter
to remount everything because it does not keep track and things
go out of control.
Differentiating between types of remove events such as the one
described above (generated by BLKRRPART) and one where the device
is physically plugged out is only possible using the DEVPATH variable
which is cleaned up only when the device is actually plugged-out.
This fixes the above anomaly by only mounting a device in add event
which is cleaned up properly (tmp cache deleted) in the remove event
or is not present in the tmp cache while making use of the DEVPATH
variable during the remove action.

Signed-off-by: Awais Belal <awais_belal@mentor.com>
Signed-off-by: Muhammad Hamza <muhammad_hamza@mentor.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

1 files changed, 27 insertions, 7 deletions

diff --git a/meta/recipes-core/udev/udev-extraconf/mount.sh b/meta/recipes-core/udev/udev-extraconf/mount.sh
index c4695ee27d..537828e3e3 100644
--- a/meta/recipes-core/udev/udev-extraconf/mount.sh
+++ b/meta/recipes-core/udev/udev-extraconf/mount.sh
@@ -45,6 +45,13 @@ automount_systemd() {
         return
     fi
 
+    # Only go for auto-mounting when the device has been cleaned up in remove
+    # or has not been identified yet
+    if [ -e "/tmp/.automount-$name" ]; then
+            logger "mount.sh/automount" "[$MOUNT_BASE/$name] is already cached"
+            return
+    fi
+
     # Skip the partition which are already in /etc/fstab
     grep "^[[:space:]]*$DEVNAME" /etc/fstab && return
     for n in LABEL PARTLABEL UUID PARTUUID; do
@@ -100,6 +107,13 @@ automount() {
 	# Get the unique name for mount point
 	get_label_name "${DEVNAME}"
 
+        # Only go for auto-mounting when the device has been cleaned up in remove
+        # or has not been identified yet
+        if [ -e "/tmp/.automount-$name" ]; then
+                logger "mount.sh/automount" "[$MOUNT_BASE/$name] is already cached"
+                return
+        fi
+
 	! test -d "$MOUNT_BASE/$name" && mkdir -p "$MOUNT_BASE/$name"
 	# Silent util-linux's version of mounting auto
 	if [ "x`readlink $MOUNT`" = "x/bin/mount.util-linux" ] ;
@@ -172,12 +186,18 @@ if [ "$ACTION" = "add" ] && [ -n "$DEVNAME" ] && [ -n "$ID_FS_TYPE" -o "$media_t
 fi
 
 if [ "$ACTION" = "remove" ] || [ "$ACTION" = "change" ] && [ -x "$UMOUNT" ] && [ -n "$DEVNAME" ]; then
-    for mnt in `cat /proc/mounts | grep "$DEVNAME" | cut -f 2 -d " " `
-    do
-        $UMOUNT $mnt
-    done
-
-    # Remove empty directories from auto-mounter
     name="`basename "$DEVNAME"`"
-    test -e "/tmp/.automount-$name" && rm_dir "$MOUNT_BASE/$name"
+    tmpfile=`find /tmp | grep "\.automount-.*${name}$"`
+    if [ ! -e "/sys/$DEVPATH" -a -e "$tmpfile" ]; then
+        logger "mount.sh/remove" "cleaning up $DEVNAME, was mounted by the auto-mounter"
+        for mnt in `cat /proc/mounts | grep "$DEVNAME" | cut -f 2 -d " " `
+        do
+                $UMOUNT $mnt
+        done
+        # Remove mount directory created by the auto-mounter
+        # and clean up our tmp cache file
+        mntdir=`cat "$tmpfile"`
+        rm_dir "$MOUNT_BASE/$mntdir"
+        rm "$tmpfile"
+    fi
 fi