From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Tue, 29 Mar 2016 23:13:45 +0000 (-0700)
Subject: f2fs: add BUG_ON to avoid unnecessary flow
X-Git-Tag: v4.7-rc1~84^2~65
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=ff37355886ac2082cee594aa949c08e2cfb33aa0;p=karo-tx-linux.git

f2fs: add BUG_ON to avoid unnecessary flow

This patch adds BUG_ON instead of retrying loop.
In the case of node pages, we already got this inode page, but unlocked it.
By the fact that we don't truncate any node pages in operations, the page's
mapping should be unchangeable.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index ade221c9756b..095fc2c96e16 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -832,7 +832,7 @@ int truncate_inode_blocks(struct inode *inode, pgoff_t from)
 	trace_f2fs_truncate_inode_blocks_enter(inode, from);
 
 	level = get_node_path(inode, from, offset, noffset);
-restart:
+
 	page = get_node_page(sbi, inode->i_ino);
 	if (IS_ERR(page)) {
 		trace_f2fs_truncate_inode_blocks_exit(inode, PTR_ERR(page));
@@ -896,10 +896,7 @@ skip_partial:
 		if (offset[1] == 0 &&
 				ri->i_nid[offset[0] - NODE_DIR1_BLOCK]) {
 			lock_page(page);
-			if (unlikely(page->mapping != NODE_MAPPING(sbi))) {
-				f2fs_put_page(page, 1);
-				goto restart;
-			}
+			BUG_ON(page->mapping != NODE_MAPPING(sbi));
 			f2fs_wait_on_page_writeback(page, NODE, true);
 			ri->i_nid[offset[0] - NODE_DIR1_BLOCK] = 0;
 			set_page_dirty(page);