f2fs: should convert inline_data during the mkwrite

If mkwrite is called to an inode having inline_data, it can overwrite the data
index space as NEW_ADDR. (e.g., the first 4 bytes are coincidently zero)
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -946,7 +946,7 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping,
 
 	f2fs_balance_fs(sbi);
 repeat:
-	err = f2fs_convert_inline_data(inode, pos + len);
+	err = f2fs_convert_inline_data(inode, pos + len, NULL);
 	if (err)
 		goto fail;
 

fs/f2fs/f2fs.h

@@ -1439,7 +1439,7 @@ extern const struct inode_operations f2fs_special_inode_operations;
  */
 bool f2fs_may_inline(struct inode *);
 int f2fs_read_inline_data(struct inode *, struct page *);
-int f2fs_convert_inline_data(struct inode *, pgoff_t);
+int f2fs_convert_inline_data(struct inode *, pgoff_t, struct page *);
 int f2fs_write_inline_data(struct inode *, struct page *, unsigned int);
 void truncate_inline_data(struct inode *, u64);
 int recover_inline_data(struct inode *, struct page *);

fs/f2fs/file.c

@@ -41,6 +41,11 @@ static int f2fs_vm_page_mkwrite(struct vm_area_struct *vma,
 
 	sb_start_pagefault(inode->i_sb);
 
+	/* force to convert with normal data indices */
+	err = f2fs_convert_inline_data(inode, MAX_INLINE_DATA + 1, page);
+	if (err)
+		goto out;
+
 	/* block allocation */
 	f2fs_lock_op(sbi);
 	set_new_dnode(&dn, inode, NULL, NULL, 0);
@@ -533,7 +538,7 @@ int f2fs_setattr(struct dentry *dentry, struct iattr *attr)
 
 	if ((attr->ia_valid & ATTR_SIZE) &&
 			attr->ia_size != i_size_read(inode)) {
-		err = f2fs_convert_inline_data(inode, attr->ia_size);
+		err = f2fs_convert_inline_data(inode, attr->ia_size, NULL);
 		if (err)
 			return err;
 
@@ -622,7 +627,7 @@ static int punch_hole(struct inode *inode, loff_t offset, loff_t len)
 	loff_t off_start, off_end;
 	int ret = 0;
 
-	ret = f2fs_convert_inline_data(inode, MAX_INLINE_DATA + 1);
+	ret = f2fs_convert_inline_data(inode, MAX_INLINE_DATA + 1, NULL);
 	if (ret)
 		return ret;
 
@@ -678,7 +683,7 @@ static int expand_inode_data(struct inode *inode, loff_t offset,
 	if (ret)
 		return ret;
 
-	ret = f2fs_convert_inline_data(inode, offset + len);
+	ret = f2fs_convert_inline_data(inode, offset + len, NULL);
 	if (ret)
 		return ret;
 

fs/f2fs/inline.c

@@ -124,9 +124,10 @@ static int __f2fs_convert_inline_data(struct inode *inode, struct page *page)
 	return err;
 }
 
-int f2fs_convert_inline_data(struct inode *inode, pgoff_t to_size)
+int f2fs_convert_inline_data(struct inode *inode, pgoff_t to_size,
+						struct page *page)
 {
-	struct page *page;
+	struct page *new_page = page;
 	int err;
 
 	if (!f2fs_has_inline_data(inode))
@@ -134,17 +135,20 @@ int f2fs_convert_inline_data(struct inode *inode, pgoff_t to_size)
 	else if (to_size <= MAX_INLINE_DATA)
 		return 0;
 
-	page = grab_cache_page(inode->i_mapping, 0);
-	if (!page)
-		return -ENOMEM;
+	if (!page || page->index != 0) {
+		new_page = grab_cache_page(inode->i_mapping, 0);
+		if (!new_page)
+			return -ENOMEM;
+	}
 
-	err = __f2fs_convert_inline_data(inode, page);
-	f2fs_put_page(page, 1);
+	err = __f2fs_convert_inline_data(inode, new_page);
+	if (!page || page->index != 0)
+		f2fs_put_page(new_page, 1);
 	return err;
 }
 
 int f2fs_write_inline_data(struct inode *inode,
-			   struct page *page, unsigned size)
+				struct page *page, unsigned size)
 {
 	void *src_addr, *dst_addr;
 	struct page *ipage;