kern/77289: system hangs while trying to unmount previously removed
bkoenig at cs.tu-berlin.de
Tue Feb 8 18:40:24 PST 2005
>Synopsis: system hangs while trying to unmount previously removed media
>Arrival-Date: Wed Feb 09 02:40:22 GMT 2005
>Originator: Björn König
>Release: FreeBSD 5.3-RELEASE-p4 i386
System: FreeBSD hoppel.local 5.3-RELEASE-p4 FreeBSD 5.3-RELEASE-p4 #0: Mon Jan 10 10:02:44 CET 2005 root at hoppel.local:/usr/obj/usr/branch/RELENG_5_3/src/sys/HOPPEL i386
The system hangs while trying to unmount a filesystem of a removable media
which was already physically removed and also if it was inserted again before.
This concerns floppy disks. I also noticed similar odd behaviour with usb
pen drives, but the system reboots instead and there is lot of console output.
mount a floppy disk
% mount /dev/fd0 /mnt
remove media now and unmount the file system
% umount /mnt
the following message appears on console:
fsync: giving up on dirty: 0xc1ec5420: tag devfs, type VCHR,
usecount 4, writecount 0, refcount 4, flags (VV_OBJBUF),
lock type devfs: EXCL (count 1) by thread 0xc19adaf0 (pid 590)
and mount shows that the filesystem is still mounted. trying to unmount
it twice let the system stop working immediately.
a similar case occurs if you mount a floppy disk, remove media, insert
disk again and then unmount the file system:
umount: unmount of /mnt failed: Device not configured
try to unmount it twice - system hangs.
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