[PATCH] largefile support for accounting

[PATCH] largefile support for accounting

[Peter Staubach]

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Hi.

There is a problem in the accounting subsystem in the kernel can not
correctly handle files larger than 2GB.  The output file containing
the process accounting data can grow very large if the system is large
enough and active enough.  If the 2GB limit is reached, then the system
simply stops storing process accounting data.

Another annoying problem is that once the system reaches this 2GB limit,
then every process which exits will receive a signal, SIGXFSZ.  This
signal is generated because an attempt was made to write beyond the limit
for the file descriptor.  This signal makes it look like every process
has exited due to a signal, when in fact, they have not.

The solution is to add the O_LARGEFILE flag to the list of flags used
to open the accounting file.  The rest of the accounting support is
already largefile safe.

The changes were tested by constructing a large file (just short of 2GB),
enabling accounting, and then running enough commands to cause the
accounting data generated to increase the size of the file to 2GB.  Without
the changes, the file grows to 2GB and the last command run in the test
script appears to exit due a signal when it has not.  With the changes,
things work as expected and quietly.

There are some user level changes required so that it can deal with
largefiles, but those are being handled separately.

Signed-off-by: Peter Staubach <staubach@redhat.com>

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--- linux-2.6.12/kernel/acct.c.org	2005-06-17 15:48:29.000000000 -0400
+++ linux-2.6.12/kernel/acct.c	2005-08-10 15:12:46.000000000 -0400
@@ -220,7 +220,7 @@ asmlinkage long sys_acct(const char __us
 			return (PTR_ERR(tmp));
 		}
 		/* Difference from BSD - they don't do O_APPEND */
-		file = filp_open(tmp, O_WRONLY|O_APPEND, 0);
+		file = filp_open(tmp, O_WRONLY | O_APPEND | O_LARGEFILE, 0);
 		putname(tmp);
 		if (IS_ERR(file)) {
 			return (PTR_ERR(file));

Re: [PATCH] largefile support for accounting

[Jay Lan]

Yes, our CSA customers reported same problem. CSA already incoporated
same fix to our kernel module code. :)

Cheers,
  - jay


Peter Staubach wrote:
> Hi.
> 
> There is a problem in the accounting subsystem in the kernel can not
> correctly handle files larger than 2GB.  The output file containing
> the process accounting data can grow very large if the system is large
> enough and active enough.  If the 2GB limit is reached, then the system
> simply stops storing process accounting data.
> 
> Another annoying problem is that once the system reaches this 2GB limit,
> then every process which exits will receive a signal, SIGXFSZ.  This
> signal is generated because an attempt was made to write beyond the limit
> for the file descriptor.  This signal makes it look like every process
> has exited due to a signal, when in fact, they have not.
> 
> The solution is to add the O_LARGEFILE flag to the list of flags used
> to open the accounting file.  The rest of the accounting support is
> already largefile safe.
> 
> The changes were tested by constructing a large file (just short of 2GB),
> enabling accounting, and then running enough commands to cause the
> accounting data generated to increase the size of the file to 2GB.  Without
> the changes, the file grows to 2GB and the last command run in the test
> script appears to exit due a signal when it has not.  With the changes,
> things work as expected and quietly.
> 
> There are some user level changes required so that it can deal with
> largefiles, but those are being handled separately.
> 
> Signed-off-by: Peter Staubach <staubach@redhat.com>
> 
> 
> ------------------------------------------------------------------------
> 
> --- linux-2.6.12/kernel/acct.c.org	2005-06-17 15:48:29.000000000 -0400
> +++ linux-2.6.12/kernel/acct.c	2005-08-10 15:12:46.000000000 -0400
> @@ -220,7 +220,7 @@ asmlinkage long sys_acct(const char __us
>  			return (PTR_ERR(tmp));
>  		}
>  		/* Difference from BSD - they don't do O_APPEND */
> -		file = filp_open(tmp, O_WRONLY|O_APPEND, 0);
> +		file = filp_open(tmp, O_WRONLY | O_APPEND | O_LARGEFILE, 0);
>  		putname(tmp);
>  		if (IS_ERR(file)) {
>  			return (PTR_ERR(file));