From a9e9acaeb0a981a6dfa54b32dd756103aeefa6a7 Mon Sep 17 00:00:00 2001
From: Xue jiufei <xuejiufei@huawei.com>
Date: Wed, 4 Jun 2014 16:06:13 -0700
Subject: [PATCH] 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>
---
fs/ocfs2/alloc.c | 6 +++++-
fs/ocfs2/ocfs2.h | 1 +
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index b4deb5f750d9cd..9d8fcf2f3b947f 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -6046,7 +6046,8 @@ static void ocfs2_truncate_log_worker(struct work_struct *work)
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 @@ void ocfs2_truncate_log_shutdown(struct ocfs2_super *osb)
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 @@ int ocfs2_truncate_log_init(struct ocfs2_super *osb)
* 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;
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index 8d64a97a9d5e50..bbec539230fd4b 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -422,6 +422,7 @@ struct ocfs2_super
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.
--
GitLab