[PATCH] largefile support for accounting

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>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/kernel/acct.c b/kernel/acct.c
index 4168f63..f70e602 100644 (file)
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -220,7 +220,7 @@ asmlinkage long sys_acct(const char __user *name)
                        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));