locks: factor out generic/filesystem switch from setlock code

Factor out the code that switches between generic and filesystem-specific lock
methods; eventually we want to call this from lock managers (lockd and nfsd)
too; currently they only call the generic methods.

This patch does that for all the setlk code.
Signed-off-by: NMarc Eshel <eshel@almaden.ibm.com>
Signed-off-by: N"J. Bruce Fields" <bfields@citi.umich.edu>

fs/locks.c

@@ -1698,6 +1698,21 @@ int fcntl_getlk(struct file *filp, struct flock __user *l)
 	return error;
 }
 
+/**
+ * vfs_lock_file - file byte range lock
+ * @filp: The file to apply the lock to
+ * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
+ * @fl: The lock to be applied
+ */
+int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl)
+{
+	if (filp->f_op && filp->f_op->lock)
+		return filp->f_op->lock(filp, cmd, fl);
+	else
+		return posix_lock_file(filp, fl);
+}
+EXPORT_SYMBOL_GPL(vfs_lock_file);
+
 /* Apply the lock described by l to an open file descriptor.
  * This implements both the F_SETLK and F_SETLKW commands of fcntl().
  */
@@ -1760,11 +1775,8 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
 	if (error)
 		goto out;
 
-	if (filp->f_op && filp->f_op->lock != NULL)
-		error = filp->f_op->lock(filp, cmd, file_lock);
-	else {
 	for (;;) {
-			error = posix_lock_file(filp, file_lock);
+		error = vfs_lock_file(filp, cmd, file_lock);
 		if (error != -EAGAIN || cmd == F_SETLK)
 			break;
 		error = wait_event_interruptible(file_lock->fl_wait,
@@ -1775,7 +1787,6 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
 		locks_delete_block(file_lock);
 		break;
 	}
-	}
 
 	/*
 	 * Attempt to detect a close/fcntl race and recover by
@@ -1890,11 +1901,8 @@ int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
 	if (error)
 		goto out;
 
-	if (filp->f_op && filp->f_op->lock != NULL)
-		error = filp->f_op->lock(filp, cmd, file_lock);
-	else {
 	for (;;) {
-			error = posix_lock_file(filp, file_lock);
+		error = vfs_lock_file(filp, cmd, file_lock);
 		if (error != -EAGAIN || cmd == F_SETLK64)
 			break;
 		error = wait_event_interruptible(file_lock->fl_wait,
@@ -1905,7 +1913,6 @@ int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
 		locks_delete_block(file_lock);
 		break;
 	}
-	}
 
 	/*
 	 * Attempt to detect a close/fcntl race and recover by
@@ -1949,10 +1956,7 @@ void locks_remove_posix(struct file *filp, fl_owner_t owner)
 	lock.fl_ops = NULL;
 	lock.fl_lmops = NULL;
 
-	if (filp->f_op && filp->f_op->lock != NULL)
-		filp->f_op->lock(filp, F_SETLK, &lock);
-	else
-		posix_lock_file(filp, &lock);
+	vfs_lock_file(filp, F_SETLK, &lock);
 
 	if (lock.fl_ops && lock.fl_ops->fl_release_private)
 		lock.fl_ops->fl_release_private(&lock);

include/linux/fs.h

@@ -857,6 +857,7 @@ extern int posix_lock_file(struct file *, struct file_lock *);
 extern int posix_lock_file_wait(struct file *, struct file_lock *);
 extern int posix_unblock_lock(struct file *, struct file_lock *);
 extern int vfs_test_lock(struct file *, struct file_lock *);
+extern int vfs_lock_file(struct file *, unsigned int, struct file_lock *);
 extern int flock_lock_file_wait(struct file *filp, struct file_lock *fl);
 extern int __break_lease(struct inode *inode, unsigned int flags);
 extern void lease_get_mtime(struct inode *, struct timespec *time);