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authorJoseph Qi <joseph.qi@huawei.com>2015-08-06 15:46:23 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-08-16 20:51:50 -0700
commitf39afff6e3b541471fbe63f632e254579a7e0fb2 (patch)
treeac799d51b2ce81e2595ce5bfcd4110b7d3cccd31 /fs
parentf5dd4ec9d8460f7c5d15ebe5be755cacd1fd5d2e (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>
Diffstat (limited to 'fs')
-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 19986959d149..fa742590bc3d 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -3973,9 +3973,13 @@ 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);