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/alloc.c b/fs/ocfs2/alloc.c
index b4deb5f..9d8fcf2 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -6046,7 +6046,8 @@
void ocfs2_schedule_truncate_log_flush(struct ocfs2_super *osb,
int cancel)
{
- if (osb->osb_tl_inode) {
+ if (osb->osb_tl_inode &&
+ atomic_read(&osb->osb_tl_disable) == 0) {
/* We want to push off log flushes while truncates are
* still running. */
if (cancel)
@@ -6223,6 +6224,8 @@
int status;
struct inode *tl_inode = osb->osb_tl_inode;
+ atomic_set(&osb->osb_tl_disable, 1);
+
if (tl_inode) {
cancel_delayed_work(&osb->osb_truncate_log_wq);
flush_workqueue(ocfs2_wq);
@@ -6254,6 +6257,7 @@
* until we're sure all is well. */
INIT_DELAYED_WORK(&osb->osb_truncate_log_wq,
ocfs2_truncate_log_worker);
+ atomic_set(&osb->osb_tl_disable, 0);
osb->osb_tl_bh = tl_bh;
osb->osb_tl_inode = tl_inode;