Re: panic: unmount: dangling vnode

[Tim Bisson <tbisson@xxxxxxx>]

On Feb 9, 2010, at 6:21 PM, Matthew Dillon wrote:

:I had a ntfs read-only mount and copied a few files off of it. After that I
:tried unmounting it, which resulted in the panic mentioned in the subject. The
:core is available at leaf:~rumko/crash/vnode/*.6 and the kernel was from about
:31st Jan.

   Ok, try this patch.  It looks like NTFS accesses auxillary vnodes
   while flushing other vnodes, so a single vflush scan won't catch them
   all.  I don't even know if multiple vflushes will catch them all
   but lets try it and find out.

-Matt

diff --git a/sys/vfs/ntfs/ntfs_vfsops.c b/sys/vfs/ntfs/ntfs_vfsops.c
index d3d80d2..2a8c1a5 100644
--- a/sys/vfs/ntfs/ntfs_vfsops.c
+++ b/sys/vfs/ntfs/ntfs_vfsops.c
@@ -633,6 +633,8 @@ ntfs_unmount(struct mount *mp, int mntflags)

dprintf(("ntfs_unmount: vflushing...\n"));
error = vflush(mp, 0, flags | SKIPSYSTEM);
+ error = vflush(mp, 0, flags | SKIPSYSTEM);
+ error = vflush(mp, 0, flags | SKIPSYSTEM);
if (error) {
kprintf("ntfs_unmount: vflush failed: %d\n",error);
return (error);
@@ -649,6 +651,8 @@ ntfs_unmount(struct mount *mp, int mntflags)

/* vflush system vnodes */
error = vflush(mp, 0, flags);
+ error = vflush(mp, 0, flags);
+ error = vflush(mp, 0, flags);
if (error)
kprintf("ntfs_unmount: vflush failed(sysnodes): %d\n",error);

Hi,

I tried your patch, but it didn't solve the problem. I'm using a x86_64 kernel from Jan 30th on xen.

(gdb) bt

#0  Debugger (msg=<value optimized out>)

    at /usr/src/sys/platform/pc64/x86_64/db_interface.c:360

#1  0xffffffff8036aa0d in panic (fmt=0xffffffff8064bb8e "unmount: dangling vnode")

    at /usr/src/sys/kern/kern_shutdown.c:742

#2  0xffffffff803d3762 in dounmount (mp=0xffffffff91f64260, flags=0)

    at /usr/src/sys/kern/vfs_syscalls.c:783

#3  0xffffffff803d38d0 in sys_unmount (uap=0xffffffffb2f07b48)

    at /usr/src/sys/kern/vfs_syscalls.c:618

#4  0xffffffff805c40fa in syscall2 (frame=0xffffffffb2f07bf8)

    at /usr/src/sys/platform/pc64/x86_64/trap.c:1189

#5  0xffffffff805bcce3 in Xfast_syscall ()

    at /usr/src/sys/platform/pc64/x86_64/exception.S:304

#6  0x00007ffffffffa8f in ?? ()

Reply contains invalid hex digit 84

Here's the info I have regarding the ntfs partition I'm testing with:

vm11 /usr/src/sys/vfs/ntfs/

$ df | grep ad2

/dev/ad2                                 51200       6196     45004    12%    /mnt

vm1 /usr/src/sys/vfs/ntfs/

$ mount | grep ad2

/dev/ad2 on /mnt (ntfs, local)

vm1 /usr/src/sys/vfs/ntfs/

$ du  /mnt/

0 /mnt/$Extend

352 /mnt/boot/common

16 /mnt/boot/ficl/i386

16 /mnt/boot/ficl/ia64

81 /mnt/boot/ficl/softwords

16 /mnt/boot/ficl/sparc64

545 /mnt/boot/ficl

112 /mnt/boot/forth

1025 /mnt/boot

3221 /mnt/

Tim