f2fs: disable extent_cache for fcollapse/finsert inodes

This reduces the elapsed time to do xfstests/generic/017.

Before: 458 s
After:  390 s
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/extent_cache.c

@@ -631,6 +631,19 @@ unsigned int f2fs_destroy_extent_node(struct inode *inode)
 	return node_cnt;
 }
 
+void f2fs_drop_extent_tree(struct inode *inode)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	struct extent_tree *et = F2FS_I(inode)->extent_tree;
+
+	set_inode_flag(inode, FI_NO_EXTENT);
+
+	write_lock(&et->lock);
+	__free_extent_tree(sbi, et);
+	__drop_largest_extent(inode, 0, UINT_MAX);
+	write_unlock(&et->lock);
+}
+
 void f2fs_destroy_extent_tree(struct inode *inode)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);

fs/f2fs/f2fs.h

@@ -2297,6 +2297,7 @@ void f2fs_leave_shrinker(struct f2fs_sb_info *);
  */
 unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *, int);
 bool f2fs_init_extent_tree(struct inode *, struct f2fs_extent *);
+void f2fs_drop_extent_tree(struct inode *);
 unsigned int f2fs_destroy_extent_node(struct inode *);
 void f2fs_destroy_extent_tree(struct inode *);
 bool f2fs_lookup_extent_cache(struct inode *, pgoff_t, struct extent_info *);

fs/f2fs/file.c

@@ -1044,6 +1044,9 @@ static int f2fs_do_collapse(struct inode *inode, pgoff_t start, pgoff_t end)
 
 	f2fs_balance_fs(sbi, true);
 	f2fs_lock_op(sbi);
+
+	f2fs_drop_extent_tree(inode);
+
 	ret = __exchange_data_block(inode, inode, end, start, nrpages - end, true);
 	f2fs_unlock_op(sbi);
 	return ret;
@@ -1278,6 +1281,8 @@ static int f2fs_insert_range(struct inode *inode, loff_t offset, loff_t len)
 		idx -= nr;
 
 		f2fs_lock_op(sbi);
+		f2fs_drop_extent_tree(inode);
+
 		ret = __exchange_data_block(inode, inode, idx,
 					idx + delta, nr, false);
 		f2fs_unlock_op(sbi);