linux-kernel - [PATCH 6/8] f2fs: avoid data race between FI_DIRTY_INODE flag and update

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Message-Id: <1464926139-58252-6-git-send-email-jaegeuk@kernel.org>
Date:	Thu,  2 Jun 2016 20:55:37 -0700
From:	Jaegeuk Kim <jaegeuk@...nel.org>
To:	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	linux-f2fs-devel@...ts.sourceforge.net
Cc:	Jaegeuk Kim <jaegeuk@...nel.org>
Subject: [PATCH 6/8] f2fs: avoid data race between FI_DIRTY_INODE flag and update_inode

FI_DIRTY_INODE flag is not covered by inode page lock, so it can be unset
at any time like below.

Thread #1                        Thread #2
- lock_page(ipage)
- update i_fields
                                 - update i_size/i_blocks/and so on
				 - set FI_DIRTY_INODE
- reset FI_DIRTY_INODE
- set_page_dirty(ipage)

In this case, we can lose the latest i_field information.

Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
---
 fs/f2fs/inode.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index fb3d9bd..63c4326 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -231,6 +231,8 @@ int update_inode(struct inode *inode, struct page *node_page)
 {
 	struct f2fs_inode *ri;
 
+	f2fs_inode_synced(inode);
+
 	f2fs_wait_on_page_writeback(node_page, NODE, true);
 
 	ri = F2FS_INODE(node_page);
@@ -265,7 +267,6 @@ int update_inode(struct inode *inode, struct page *node_page)
 
 	__set_inode_rdev(inode, ri);
 	set_cold_node(inode, node_page);
-	f2fs_inode_synced(inode);
 
 	/* deleted inode */
 	if (inode->i_nlink == 0)
-- 
2.6.3