2009-06-18 05:33:17

by J. R. Okajima

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Subject: IMA and ETXTBSY


After the failure of open(2) with ETXTBSY, IMA produces wrong messages.
Here is a simple test script.

dir=/tmp
cp /bin/sleep $dir
ls -l $dir/sleep
stat -f $dir
$dir/sleep 3 & sleep 1
echo | /bin/dd of=$dir/sleep conv=notrunc && false
wait
rm $dir/sleep


The result.
+ cp /bin/sleep /tmp
+ ls -l /tmp/sleep
-rwxr-xr-x 1 jro jro 23504 Jun 18 14:26 /tmp/sleep
+ stat -f /tmp
File: "/tmp"
ID: 4e22c34ea8177d80 Namelen: 255 Type: ext2/ext3
Block size: 1024 Fundamental block size: 1024
Blocks: Total: 918322 Free: 918281 Available: 869285
Inodes: Total: 490560 Free: 490545
+ /tmp/sleep 3
+ sleep 1
+ echo
+ /bin/dd of=/tmp/sleep conv=notrunc
/bin/dd: opening `/tmp/sleep': Text file busy
+ wait
+ rm /tmp/sleep
$ iint_free: writecount: 1
iint_free: opencount: 1


J. R. Okajima


2009-06-18 23:49:51

by Mimi Zohar

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Subject: Re: IMA and ETXTBSY

[email protected] wrote on 06/18/2009 01:32:58 AM:

> After the failure of open(2) with ETXTBSY, IMA produces wrong messages.
> Here is a simple test script.
>
> dir=/tmp
> cp /bin/sleep $dir
> ls -l $dir/sleep
> stat -f $dir
> $dir/sleep 3 & sleep 1
> echo | /bin/dd of=$dir/sleep conv=notrunc && false
> wait
> rm $dir/sleep
>
>
> The result.
> + cp /bin/sleep /tmp
> + ls -l /tmp/sleep
> -rwxr-xr-x 1 jro jro 23504 Jun 18 14:26 /tmp/sleep
> + stat -f /tmp
> File: "/tmp"
> ID: 4e22c34ea8177d80 Namelen: 255 Type: ext2/ext3
> Block size: 1024 Fundamental block size: 1024
> Blocks: Total: 918322 Free: 918281 Available: 869285
> Inodes: Total: 490560 Free: 490545
> + /tmp/sleep 3
> + sleep 1
> + echo
> + /bin/dd of=/tmp/sleep conv=notrunc
> /bin/dd: opening `/tmp/sleep': Text file busy
> + wait
> + rm /tmp/sleep
> $ iint_free: writecount: 1
> iint_free: opencount: 1
>
>
> J. R. Okajima

The problem is that IMA measures the file and increments the
open/read/write counters before the file is actually opened,
but if the open fails it doesn't decrement the counters. I'll
post a patch. Thanks for bringing this to my attention.

Mimi