[PATCH] fs/locks.c: Fix lease_init

It is insane to be giving lease_init() the task of freeing the lock it is
supposed to initialise, given that the lock is not guaranteed to be
allocated on the stack. This causes lockups in fcntl_setlease().
Problem diagnosed by Daniel Hokka Zakrisson <daniel@hozac.com>

Also fix a slab leak in __setlease() due to an uninitialised return value.
Problem diagnosed by Björn Steinbrink.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Tested-by: Daniel Hokka Zakrisson <daniel@hozac.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 12 insertions, 9 deletions

diff --git a/fs/locks.c b/fs/locks.c
index efad798824dc..6f99c0a6f836 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -446,15 +446,14 @@ static struct lock_manager_operations lease_manager_ops = {
  */
 static int lease_init(struct file *filp, int type, struct file_lock *fl)
  {
+        if (assign_type(fl, type) != 0)
+                return -EINVAL;
+
         fl->fl_owner = current->files;
         fl->fl_pid = current->tgid;
 
         fl->fl_file = filp;
         fl->fl_flags = FL_LEASE;
-        if (assign_type(fl, type) != 0) {
-                locks_free_lock(fl);
-                return -EINVAL;
-        }
         fl->fl_start = 0;
         fl->fl_end = OFFSET_MAX;
         fl->fl_ops = NULL;
@@ -466,16 +465,19 @@ static int lease_init(struct file *filp, int type, struct file_lock *fl)
 static int lease_alloc(struct file *filp, int type, struct file_lock **flp)
 {
         struct file_lock *fl = locks_alloc_lock();
-        int error;
+        int error = -ENOMEM;
 
         if (fl == NULL)
-                return -ENOMEM;
+                goto out;
 
         error = lease_init(filp, type, fl);
-        if (error)
-                return error;
+        if (error) {
+                locks_free_lock(fl);
+                fl = NULL;
+        }
+out:
         *flp = fl;
-        return 0;
+        return error;
 }
 
 /* Check if two locks overlap each other.
@@ -1372,6 +1374,7 @@ static int __setlease(struct file *filp, long arg, struct file_lock **flp)
                 goto out;
 
         if (my_before != NULL) {
+                *flp = *my_before;
                 error = lease->fl_lmops->fl_change(my_before, arg);
                 goto out;
         }