commit 498052bba55ecaff58db6a1436b0e25bfd75a7ff
author Al Viro <viro@zeniv.linux.org.uk> Mon Mar 30 07:20:30 2009 -0400
committer Al Viro <viro@zeniv.linux.org.uk> Tue Mar 31 23:00:26 2009 -0400
tree bd3644ac60737e3733995a203acebd70cfd1b21b
parent 3e93cd671813e204c258f1e6c797959920cf7772

New locking/refcounting for fs_struct

* all changes of current->fs are done under task_lock and write_lock of
  old fs->lock
* refcount is not atomic anymore (same protection)
* its decrements are done when removing reference from current; at the
  same time we decide whether to free it.
* put_fs_struct() is gone
* new field - ->in_exec.  Set by check_unsafe_exec() if we are trying to do
  execve() and only subthreads share fs_struct.  Cleared when finishing exec
  (success and failure alike).  Makes CLONE_FS fail with -EAGAIN if set.
* check_unsafe_exec() may fail with -EAGAIN if another execve() from subthread
  is in progress.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/proc/task_nommu.c

diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index 343ea12..6ca0105 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -49,7 +49,7 @@
 	else
 		bytes += kobjsize(mm);
 	
-	if (current->fs && atomic_read(&current->fs->count) > 1)
+	if (current->fs && current->fs->users > 1)
 		sbytes += kobjsize(current->fs);
 	else
 		bytes += kobjsize(current->fs);