This is a note to let you know that I've just added the patch titled
ocfs2: fix BUG in ocfs2_downconvert_thread_do_work()
to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ocfs2-fix-bug-in-ocfs2_downconvert_thread_do_work.patch
and it can be found in the queue-4.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 209f7512d007980fd111a74a064d70a3656079cf Mon Sep 17 00:00:00 2001
From: Joseph Qi <[email protected]>
Date: Thu, 6 Aug 2015 15:46:23 -0700
Subject: ocfs2: fix BUG in ocfs2_downconvert_thread_do_work()
From: Joseph Qi <[email protected]>
commit 209f7512d007980fd111a74a064d70a3656079cf upstream.
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 <[email protected]>
Cc: Mark Fasheh <[email protected]>
Cc: Joel Becker <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/ocfs2/dlmglue.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -4025,9 +4025,13 @@ static void ocfs2_downconvert_thread_do_
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);
Patches currently in stable-queue which might be from [email protected] are
queue-4.1/ocfs2-fix-bug-in-ocfs2_downconvert_thread_do_work.patch
queue-4.1/ocfs2-fix-shift-left-overflow.patch
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