[PATCH 6/8] f2fs: avoid data race between FI_DIRTY_INODE flag and update_inode

From: Jaegeuk Kim
Date: Thu Jun 02 2016 - 23:56:07 EST


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@xxxxxxxxxx>
---
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