Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

ocfs2: fix BUG in ocfs2_downconvert_thread_do_work()

Browse source 
The "BUG_ON(list_empty(&osb->blocked_lock_list))" in
ocfs2_downconvert_thread_do_work can be triggered in the following case:

ocfs2dc has firstly saved osb->blocked_lock_count to local varibale
processed, and then processes the dentry lockres.  During the dentry
put, it calls iput and then deletes rw, inode and open lockres from
blocked list in ocfs2_mark_lockres_freeing.  And this causes the
variable `processed' to not reflect the number of blocked lockres to be
processed, which triggers the BUG.

Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Joseph Qi 2015-08-06 15:46:23 -07:00 committed by Linus Torvalds
parent 4248b0da46
commit 209f7512d0
1 changed files with 7 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

10
fs/ocfs2/dlmglue.c
View file

@ -4025,9 +4025,13 @@ static void ocfs2_downconvert_thread_do_work(struct ocfs2_super *osb)
osb->dc_work_sequence = osb->dc_wake_sequence;
processed = osb->blocked_lock_count;
while (processed) {
BUG_ON(list_empty(&osb->blocked_lock_list));
/*
* blocked lock processing in this loop might call iput which can
* remove items off osb->blocked_lock_list. Downconvert up to
* 'processed' number of locks, but stop short if we had some
* removed in ocfs2_mark_lockres_freeing when downconverting.
*/
while (processed && !list_empty(&osb->blocked_lock_list)) {
lockres = list_entry(osb->blocked_lock_list.next,
struct ocfs2_lock_res, l_blocked_list);
list_del_init(&lockres->l_blocked_list);