f2fs: invalidate inmemory page

If user truncates file's data, we should truncate inmemory pages too.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -1116,6 +1116,9 @@ static void f2fs_invalidate_data_page(struct page *page, unsigned int offset,
 	if (offset % PAGE_CACHE_SIZE || length != PAGE_CACHE_SIZE)
 		return;
 
+	if (f2fs_is_atomic_file(inode) || f2fs_is_volatile_file(inode))
+		invalidate_inmem_page(inode, page);
+
 	if (PageDirty(page))
 		inode_dec_dirty_pages(inode);
 	ClearPagePrivate(page);

fs/f2fs/f2fs.h

@@ -1297,6 +1297,7 @@ void destroy_node_manager_caches(void);
  * segment.c
  */
 void register_inmem_page(struct inode *, struct page *);
+void invalidate_inmem_page(struct inode *, struct page *);
 void commit_inmem_pages(struct inode *, bool);
 void f2fs_balance_fs(struct f2fs_sb_info *);
 void f2fs_balance_fs_bg(struct f2fs_sb_info *);

fs/f2fs/segment.c

@@ -203,6 +203,22 @@ void register_inmem_page(struct inode *inode, struct page *page)
 	mutex_unlock(&fi->inmem_lock);
 }
 
+void invalidate_inmem_page(struct inode *inode, struct page *page)
+{
+	struct f2fs_inode_info *fi = F2FS_I(inode);
+	struct inmem_pages *cur;
+
+	mutex_lock(&fi->inmem_lock);
+	cur = radix_tree_lookup(&fi->inmem_root, page->index);
+	if (cur) {
+		radix_tree_delete(&fi->inmem_root, cur->page->index);
+		f2fs_put_page(cur->page, 0);
+		list_del(&cur->list);
+		kmem_cache_free(inmem_entry_slab, cur);
+	}
+	mutex_unlock(&fi->inmem_lock);
+}
+
 void commit_inmem_pages(struct inode *inode, bool abort)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);