From 508b1b57f73a49effc975731f8b76325d45b0e0f Mon Sep 17 00:00:00 2001
From: zhanchengbin <zhanchengbin1@huawei.com>
Date: Fri, 18 Mar 2022 00:02:50 +0800
Subject: [PATCH] e2fsck: handle->level is overflow in ext2fs_extent_get.

In function check_blocks_extents, program call scan_extent_node recursively until
leaf extent is found, and if this leaf extent is the last one in this extent_idx,
it will delete the parent extent_idx of this leaf extent in ext2fs_extent_delete,
and do handle->level--. After scan_extent_node return, program allways to get up extent,
but level was already decreased.
So calling ext2fs_extent_get(EXT2_EXTENT_UP) again will return EXT2_ET_EXTENT_NO_UP,
and then print failed. 

Signed-off-by: zhanchengbin <zhanchengbin1@huawei.com>
---
 e2fsck/pass1.c      | 7 +++++++
 lib/ext2fs/ext2fs.h | 1 +
 lib/ext2fs/extent.c | 5 +++++
 3 files changed, 13 insertions(+)

diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
index 26b9ab71..3d698934 100644
--- a/e2fsck/pass1.c
+++ b/e2fsck/pass1.c
@@ -3074,11 +3074,18 @@ report_problem:
 					}
 				}
 			}
+
+			int level_bak = ext2fs_current_level_get(ehandle);
+
 			scan_extent_node(ctx, pctx, pb, extent.e_lblk,
 					 last_lblk, eof_block, ehandle,
 					 next_try_repairs);
 			if (pctx->errcode)
 				return;
+
+			if (level_bak != ext2fs_current_level_get(ehandle))
+				return;
+
 			pctx->errcode = ext2fs_extent_get(ehandle,
 						  EXT2_EXTENT_UP, &extent);
 			if (pctx->errcode) {
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index 68f9c1fe..d0468f11 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -1333,6 +1333,7 @@ extern errcode_t ext2fs_extent_open2(ext2_filsys fs, ext2_ino_t ino,
 extern void ext2fs_extent_free(ext2_extent_handle_t handle);
 extern errcode_t ext2fs_extent_get(ext2_extent_handle_t handle,
 				   int flags, struct ext2fs_extent *extent);
+extern int ext2fs_current_level_get(ext2_extent_handle_t handle);
 extern errcode_t ext2fs_extent_node_split(ext2_extent_handle_t handle);
 extern errcode_t ext2fs_extent_replace(ext2_extent_handle_t handle, int flags,
 				       struct ext2fs_extent *extent);
diff --git a/lib/ext2fs/extent.c b/lib/ext2fs/extent.c
index b324c7b0..07acd4e0 100644
--- a/lib/ext2fs/extent.c
+++ b/lib/ext2fs/extent.c
@@ -575,6 +575,11 @@ retry:
 	return 0;
 }
 
+int ext2fs_current_level_get(ext2_extent_handle_t handle)
+{
+	return handle->level;
+}
+
 static errcode_t update_path(ext2_extent_handle_t handle)
 {
 	blk64_t				blk;
-- 
2.27.0