linux-toradex.git/kernel/acct.c, branch v2.6.27-rc4

bsdacct: fix and add comments around acct_process()

2008-07-25T17:53:47+00:00

Fix the one describing what this function is and add one more - about
locking absence around pid namespaces loop.

Signed-off-by: Pavel Emelyanov 
Cc: Randy Dunlap 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bsdacct: account dying tasks in all relevant namespaces

2008-07-25T17:53:47+00:00

This just makes the acct_proces walk the pid namespaces from current up to
the top and account a task in each with the accounting turned on.

ns->parent access if safe lockless, since current it still alive and holds
its namespace, which in turn holds its parent.

Signed-off-by: Pavel Emelyanov 
Cc: Balbir Singh 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bsdacct: turn acct off for all pidns-s on umount time

2008-07-25T17:53:47+00:00

All the bsd_acct_strcts with opened accounting are linked into a global
list.  So, the acct_auto_close(_mnt) walks one and drops the accounting
for each.

Signed-off-by: Pavel Emelyanov 
Cc: Balbir Singh 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bsdacct: switch from global bsd_acct_struct instance to per-pidns one

2008-07-25T17:53:47+00:00

Allocate the structure on the first call to sys_acct().  After this each
namespace, that ordered the accounting, will live with this structure till
its own death.

Two notes
- routines, that close the accounting on fs umount time use
  the init_pid_ns's acct by now;
- accounting routine accounts to dying task's namespace
  (also by now).

Signed-off-by: Pavel Emelyanov 
Cc: Balbir Singh 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bsdacct: make internal code work with passed bsd_acct_struct, not global

2008-07-25T17:53:47+00:00

This adds the appropriate pointer to all the internal (i.e.  static)
functions that work with global acct instance.  API calls pass a global
instance to them (while we still have such).

Mostly this is a s/acct_globals./acct->/ over the file.

Signed-off-by: Pavel Emelyanov 
Cc: Balbir Singh 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bsdacct: turn the acct_lock from on-the-struct to global

2008-07-25T17:53:47+00:00

Don't use per-bsd-acct-struct lock, but work with a global one.

This lock is taken for short periods, so it doesn't seem it'll become a
bottleneck, but it will allow us to easily avoid many locking difficulties
in the future.

So this is a mostly s/acct_globals.lock/acct_lock/ over the file.

Signed-off-by: Pavel Emelyanov 
Cc: Balbir Singh 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bsdacct: make check timer accept a bsd_acct_struct argument

2008-07-25T17:53:46+00:00

We're going to have many bsd_acct_struct instances, not just one, so the
timer (currently working with a global one) has to know which one to work
with.

Use a handy setup_timer macro for it (thanks to Oleg for one).

Signed-off-by: Pavel Emelyanov 
Cc: Balbir Singh 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bsdacct: "truthify" a comment near acct_process

2008-07-25T17:53:46+00:00

The acct_process does not accept any arguments actually.

Signed-off-by: Pavel Emelyanov 
Cc: Balbir Singh 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bsdacct: rename acct_gbls to bsd_acct_struct

2008-07-25T17:53:46+00:00

After I fixed access to task->tgid in kernel/acct.c, Oleg pointed out some
bad side effects with this accounting vs pid namespaces interaction.  I.e.
 when some task in pid namespace sets this accounting up, this blocks all
the others from doing the same.  Restricting this to init namespace only
could help, but didn't look a graceful solution.

So here is the approach to make this accounting work with pid namespaces
properly.

The idea is simple - when a task dies it accounts itself in each namespace
it is visible from and which set the accounting up.

For example here are the commands run and the output of lastcomm from init
and sub namespaces:

init_ns# accton pacct
 sub_ns# accton pacct (this is a different file - sub ns is run in
                       a chroot-ed environment)
init_ns# cat /dev/null
 sub_ns# ls /dev/null
init_ns# accton
 sub_ns# accton

 sub_ns#  lastcomm -f pacct
ls                      0        [136,0]    0.00 secs Thu May 15 10:30
accton                  0        [136,0]    0.00 secs Thu May 15 10:30

init_ns# lastcomm -f pacct
accton                  root     pts/0      0.00 secs Thu May 15 14:30 << got from sub
cat                     root     pts/1      0.00 secs Thu May 15 14:30
ls                      root     pts/0      0.00 secs Thu May 15 14:30 << got from sub
accton                  root     pts/1      0.00 secs Thu May 15 14:30

That was the summary, the details are in patches.

This patch:

It will be visible in pid_namespace.h file, so fix its name to look better
outside the acct.c file.

Signed-off-by: Pavel Emelyanov 
Cc: Balbir Singh 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bsd_acct: using task_struct->tgid is not right in pid-namespaces

2008-03-25T02:22:20+00:00

In case we're accounting from a sub-namespace, the tgids reported will not
refer to the right namespace.

Save the pid_namespace we're accounting in on the acct_glbs and use it in
do_acct_process.

Two less :) places using the task_struct.tgid member.

Signed-off-by: Pavel Emelyanov 
Cc: Oleg Nesterov 
Cc: "Paul E. McKenney" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds