From: Liu Bo <bo.li.liu@oracle.com>
Date: Thu, 25 Jan 2018 18:02:51 +0000 (-0700)
Subject: Btrfs: fix crash due to not cleaning up tree log block's dirty bits
X-Git-Tag: v4.1.50~172
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=1b555cf3a4d7404c659606606b873e5a5786ea6e;p=users%2Fdwmw2%2Flinux.git

Btrfs: fix crash due to not cleaning up tree log block's dirty bits

[ Upstream commit 1846430c24d66e85cc58286b3319c82cd54debb2 ]

In cases that the whole fs flips into readonly status due to failures in
critical sections, then log tree's blocks are still dirty, and this leads
to a crash during umount time, the crash is about use-after-free,

umount
 -> close_ctree
    -> stop workers
    -> iput(btree_inode)
       -> iput_final
          -> write_inode_now
	     -> ...
	       -> queue job on stop'd workers

cc: <stable@vger.kernel.org> v3.12+
Fixes: 681ae50917df ("Btrfs: cleanup reserved space when freeing tree log on error")
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 6ee954c62fe6c..3cd1abf692dd3 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2343,6 +2343,9 @@ static noinline int walk_down_log_tree(struct btrfs_trans_handle *trans,
 							next);
 					btrfs_wait_tree_block_writeback(next);
 					btrfs_tree_unlock(next);
+				} else {
+					if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &next->bflags))
+						clear_extent_buffer_dirty(next);
 				}
 
 				WARN_ON(root_owner !=
@@ -2422,6 +2425,9 @@ static noinline int walk_up_log_tree(struct btrfs_trans_handle *trans,
 							next);
 					btrfs_wait_tree_block_writeback(next);
 					btrfs_tree_unlock(next);
+				} else {
+					if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &next->bflags))
+						clear_extent_buffer_dirty(next);
 				}
 
 				WARN_ON(root_owner != BTRFS_TREE_LOG_OBJECTID);
@@ -2498,6 +2504,9 @@ static int walk_log_tree(struct btrfs_trans_handle *trans,
 				clean_tree_block(trans, log->fs_info, next);
 				btrfs_wait_tree_block_writeback(next);
 				btrfs_tree_unlock(next);
+			} else {
+				if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &next->bflags))
+					clear_extent_buffer_dirty(next);
 			}
 
 			WARN_ON(log->root_key.objectid !=