ocfs2: fix umount hang while shutting down truncate log
Revert commit 75f82eaa502c ("ocfs2: fix NULL pointer dereference when
dismount and ocfs2rec simultaneously") because it may cause a umount
hang while shutting down the truncate log.
fix NULL pointer dereference when dismount and ocfs2rec simultaneously
The situation is as followes:
ocfs2_dismout_volume
-> ocfs2_recovery_exit
-> free osb->recovery_map
-> ocfs2_truncate_shutdown
-> lock global bitmap inode
-> ocfs2_wait_for_recovery
-> check whether osb->recovery_map->rm_used is zero
Because osb->recovery_map is already freed, rm_used can be any other
values, so it may yield umount hang.
To prevent NULL pointer dereference while getting sys_root_inode, we use
a osb_tl_disable flag to disable schedule osb_truncate_log_wq after
truncate log shutdown.
Signed-off-by: joyce.xue <xuejiufei@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index 8d64a97..bbec539 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -422,6 +422,7 @@
struct inode *osb_tl_inode;
struct buffer_head *osb_tl_bh;
struct delayed_work osb_truncate_log_wq;
+ atomic_t osb_tl_disable;
/*
* How many clusters in our truncate log.
* It must be protected by osb_tl_inode->i_mutex.