linux-ext4 - Re: busy inodes -> ext3 umount crash

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Message-ID: <4BCC69B4.2050308@gmail.com>
Date:	Mon, 19 Apr 2010 16:33:24 +0200
From:	Jiri Slaby <jirislaby@...il.com>
To:	Jan Kara <jack@...e.cz>
CC:	Andrew Morton <akpm@...ux-foundation.org>, adilger@....com,
	linux-ext4@...r.kernel.org,
	Linux kernel mailing list <linux-kernel@...r.kernel.org>,
	mszeredi@...e.cz
Subject: Re: busy inodes -> ext3 umount crash

On 04/19/2010 04:11 PM, Jan Kara wrote:
>> I have no idea how to reproduce it :(, but it usually happens when I do
>> shutdown/kexec.
>   If it's the patch I suspect above, then moving one directory over another
> one might trigger the leak which would be later spotted on umount of the
> filesystem. Or maybe to trigger the leak you have to have a process which
> has its CWD in the directory you are going to delete by the rename... not
> sure.

The trigger for busy inodes is as simple as (I=initialization done only
once):
I> # dd if=/dev/zero of=/dev/shm/ext3 bs=1024 count=1 seek=$((100*1024))
I> # mkfs.ext3 -m 0 /dev/shm/ext3
# mount -oloop /dev/shm/ext3 /mnt/c
# umount /mnt/c
# dmesg|tail
VFS: Busy inodes after unmount of loop0. Self-destruct in 5 seconds.
Have a nice day...

(The printk time varies -- this sequence really suffices.)

> So if you can easily reproduce
> the "busy inodes" message then I'd start with debugging that one. Do you
> see it also with vanilla kernels?

I don't know, now I'm going to play with that as I have the trigger ;).
Will be back soon.

thanks,
-- 
js
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