From: Chao Yu <chao2.yu@samsung.com>
Date: Thu, 12 Jun 2014 05:31:50 +0000 (+0800)
Subject: f2fs: avoid to truncate non-updated page partially
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=ca0a81b397b5f153ac2a9880c5e85b08b0447e4e;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

f2fs: avoid to truncate non-updated page partially

After we call find_data_page in truncate_partial_data_page, we could not
guarantee this page is updated or not as error may occurred in lower layer.

We'd better check status of the page to avoid this no updated page be
writebacked to device.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 7d8b96275092..36fa50587bb8 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -380,13 +380,15 @@ static void truncate_partial_data_page(struct inode *inode, u64 from)
 		return;
 
 	lock_page(page);
-	if (unlikely(page->mapping != inode->i_mapping)) {
-		f2fs_put_page(page, 1);
-		return;
-	}
+	if (unlikely(!PageUptodate(page) ||
+			page->mapping != inode->i_mapping))
+		goto out;
+
 	f2fs_wait_on_page_writeback(page, DATA);
 	zero_user(page, offset, PAGE_CACHE_SIZE - offset);
 	set_page_dirty(page);
+
+out:
 	f2fs_put_page(page, 1);
 }