summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorJoseph Qi <joseph.qi@huawei.com>2015-08-06 15:46:23 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-08-16 20:51:40 -0700
commit2a4cb7b52d728b1f6b76e73ea0277f422da1ffac (patch)
treee5179b0ad5f2cbecf630968cf3194f6e75a765ab
parent2934eb36cf564b6e368d8b43eb48384b308e04e7 (diff)
ocfs2: fix BUG in ocfs2_downconvert_thread_do_work()
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 <joseph.qi@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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/ocfs2/dlmglue.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index 3a44a648dae7..b294deb27d17 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -3971,9 +3971,13 @@ 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);