f2fs: revisit inline_data to avoid data races and potential bugs

This patch simplifies the inline_data usage with the following rule.
1. inline_data is set during the file creation.
2. If new data is requested to be written ranges out of inline_data,
 f2fs converts that inode permanently.
3. There is no cases which converts non-inline_data inode to inline_data.
4. The inline_data flag should be changed under inode page lock.

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

1 files changed, 32 insertions, 1 deletions

diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index 4131e3cfd1cf..9fe110ef8cc4 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -67,12 +67,38 @@ static void __set_inode_rdev(struct inode *inode, struct f2fs_inode *ri)
 	}
 }
 
+static int __recover_inline_status(struct inode *inode, struct page *ipage)
+{
+	void *inline_data = inline_data_addr(ipage);
+	struct f2fs_inode *ri;
+	void *zbuf;
+
+	zbuf = kzalloc(MAX_INLINE_DATA, GFP_NOFS);
+	if (!zbuf)
+		return -ENOMEM;
+
+	if (!memcmp(zbuf, inline_data, MAX_INLINE_DATA)) {
+		kfree(zbuf);
+		return 0;
+	}
+	kfree(zbuf);
+
+	f2fs_wait_on_page_writeback(ipage, NODE);
+	set_inode_flag(F2FS_I(inode), FI_DATA_EXIST);
+
+	ri = F2FS_INODE(ipage);
+	set_raw_inline(F2FS_I(inode), ri);
+	set_page_dirty(ipage);
+	return 0;
+}
+
 static int do_read_inode(struct inode *inode)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct f2fs_inode_info *fi = F2FS_I(inode);
 	struct page *node_page;
 	struct f2fs_inode *ri;
+	int err = 0;
 
 	/* Check if ino is within scope */
 	if (check_nid_range(sbi, inode->i_ino)) {
@@ -114,11 +140,15 @@ static int do_read_inode(struct inode *inode)
 	get_extent_info(&fi->ext, ri->i_ext);
 	get_inline_info(fi, ri);
 
+	/* check data exist */
+	if (f2fs_has_inline_data(inode) && !f2fs_exist_data(inode))
+		err = __recover_inline_status(inode, node_page);
+
 	/* get rdev by using inline_info */
 	__get_inode_rdev(inode, ri);
 
 	f2fs_put_page(node_page, 1);
-	return 0;
+	return err;
 }
 
 struct inode *f2fs_iget(struct super_block *sb, unsigned long ino)
@@ -329,6 +359,7 @@ void handle_failed_inode(struct inode *inode)
 
 	remove_inode_page(inode);
 
+	clear_inode_flag(F2FS_I(inode), FI_INLINE_DATA);
 	clear_inode_flag(F2FS_I(inode), FI_INLINE_DENTRY);
 	alloc_nid_failed(sbi, inode->i_ino);
 	f2fs_unlock_op(sbi);