1 files changed, 39 insertions, 36 deletions

diff --git a/fs/locks.c b/fs/locks.c
index 4d9e71d43e7e..ab61a8b54829 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -168,18 +168,9 @@ static void locks_release_private(struct file_lock *fl)
 /* Free a lock which is not in use. */
 static void locks_free_lock(struct file_lock *fl)
 {
-	if (fl == NULL) {
-		BUG();
-		return;
-	}
-	if (waitqueue_active(&fl->fl_wait))
-		panic("Attempting to free lock with active wait queue");
-
-	if (!list_empty(&fl->fl_block))
-		panic("Attempting to free lock with active block list");
-
-	if (!list_empty(&fl->fl_link))
-		panic("Attempting to free lock on active lock list");
+	BUG_ON(waitqueue_active(&fl->fl_wait));
+	BUG_ON(!list_empty(&fl->fl_block));
+	BUG_ON(!list_empty(&fl->fl_link));
 
 	locks_release_private(fl);
 	kmem_cache_free(filelock_cache, fl);
@@ -455,15 +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;
@@ -475,16 +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.
@@ -735,8 +728,9 @@ EXPORT_SYMBOL(posix_locks_deadlock);
  * at the head of the list, but that's secret knowledge known only to
  * flock_lock_file and posix_lock_file.
  */
-static int flock_lock_file(struct file *filp, struct file_lock *new_fl)
+static int flock_lock_file(struct file *filp, struct file_lock *request)
 {
+	struct file_lock *new_fl = NULL;
 	struct file_lock **before;
 	struct inode * inode = filp->f_dentry->d_inode;
 	int error = 0;
@@ -751,17 +745,20 @@ static int flock_lock_file(struct file *filp, struct file_lock *new_fl)
 			continue;
 		if (filp != fl->fl_file)
 			continue;
-		if (new_fl->fl_type == fl->fl_type)
+		if (request->fl_type == fl->fl_type)
 			goto out;
 		found = 1;
 		locks_delete_lock(before);
 		break;
 	}
-	unlock_kernel();
 
-	if (new_fl->fl_type == F_UNLCK)
-		return 0;
+	if (request->fl_type == F_UNLCK)
+		goto out;
 
+	error = -ENOMEM;
+	new_fl = locks_alloc_lock();
+	if (new_fl == NULL)
+		goto out;
 	/*
 	 * If a higher-priority process was blocked on the old file lock,
 	 * give it the opportunity to lock the file.
@@ -769,26 +766,28 @@ static int flock_lock_file(struct file *filp, struct file_lock *new_fl)
 	if (found)
 		cond_resched();
 
-	lock_kernel();
 	for_each_lock(inode, before) {
 		struct file_lock *fl = *before;
 		if (IS_POSIX(fl))
 			break;
 		if (IS_LEASE(fl))
 			continue;
-		if (!flock_locks_conflict(new_fl, fl))
+		if (!flock_locks_conflict(request, fl))
 			continue;
 		error = -EAGAIN;
-		if (new_fl->fl_flags & FL_SLEEP) {
-			locks_insert_block(fl, new_fl);
-		}
+		if (request->fl_flags & FL_SLEEP)
+			locks_insert_block(fl, request);
 		goto out;
 	}
+	locks_copy_lock(new_fl, request);
 	locks_insert_lock(&inode->i_flock, new_fl);
+	new_fl = NULL;
 	error = 0;
 
 out:
 	unlock_kernel();
+	if (new_fl)
+		locks_free_lock(new_fl);
 	return error;
 }
 
@@ -1377,6 +1376,7 @@ 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;
 	}
@@ -1569,9 +1569,7 @@ asmlinkage long sys_flock(unsigned int fd, unsigned int cmd)
 		error = flock_lock_file_wait(filp, lock);
 
  out_free:
-	if (list_empty(&lock->fl_link)) {
-		locks_free_lock(lock);
-	}
+	locks_free_lock(lock);
 
  out_putf:
 	fput(filp);
@@ -2237,7 +2235,12 @@ void steal_locks(fl_owner_t from)
 
 	lock_kernel();
 	j = 0;
-	rcu_read_lock();
+
+	/*
+	 * We are not taking a ref to the file structures, so
+	 * we need to acquire ->file_lock.
+	 */
+	spin_lock(&files->file_lock);
 	fdt = files_fdtable(files);
 	for (;;) {
 		unsigned long set;
@@ -2255,7 +2258,7 @@ void steal_locks(fl_owner_t from)
 			set >>= 1;
 		}
 	}
-	rcu_read_unlock();
+	spin_unlock(&files->file_lock);
 	unlock_kernel();
 }
 EXPORT_SYMBOL(steal_locks);