Andrew Morton
2019-Oct-07 22:11 UTC
[Ocfs2-devel] [PATCH] ocfs2: move the mlog from the spinlock to outside
On Mon, 30 Sep 2019 11:17:39 +0800 Shuning Zhang <sunny.s.zhang at oracle.com> wrote:> There is a potential task of deadlock. Because the mask > is 0, the deadlock does not occur now. But There is a > potential task. If someone change the mask of mlog, but > forget to modify the order of the mlog and spin_unlock, > There will be a potential deadlock.So I move the mlog > from the spinlock to outsize. > > ... > > --- a/fs/ocfs2/dlmglue.c > +++ b/fs/ocfs2/dlmglue.c > @@ -2315,10 +2315,10 @@ static int ocfs2_inode_lock_update(struct inode *inode, > > spin_lock(&oi->ip_lock); > if (oi->ip_flags & OCFS2_INODE_DELETED) { > + spin_unlock(&oi->ip_lock); > mlog(0, "Orphaned inode %llu was deleted while we " > "were waiting on a lock. ip_flags = 0x%x\n", > (unsigned long long)oi->ip_blkno, oi->ip_flags); > - spin_unlock(&oi->ip_lock); > status = -ENOENT; > goto bail; > }The patch is obviously OK but I don't see any deadlock. mlog() doesn't take any locks?
Joseph Qi
2019-Oct-08 01:14 UTC
[Ocfs2-devel] [PATCH] ocfs2: move the mlog from the spinlock to outside
On 19/10/8 06:11, Andrew Morton wrote:> On Mon, 30 Sep 2019 11:17:39 +0800 Shuning Zhang <sunny.s.zhang at oracle.com> wrote: > >> There is a potential task of deadlock. Because the mask >> is 0, the deadlock does not occur now. But There is a >> potential task. If someone change the mask of mlog, but >> forget to modify the order of the mlog and spin_unlock, >> There will be a potential deadlock.So I move the mlog >> from the spinlock to outsize. >> >> ... >> >> --- a/fs/ocfs2/dlmglue.c >> +++ b/fs/ocfs2/dlmglue.c >> @@ -2315,10 +2315,10 @@ static int ocfs2_inode_lock_update(struct inode *inode, >> >> spin_lock(&oi->ip_lock); >> if (oi->ip_flags & OCFS2_INODE_DELETED) { >> + spin_unlock(&oi->ip_lock); >> mlog(0, "Orphaned inode %llu was deleted while we " >> "were waiting on a lock. ip_flags = 0x%x\n", >> (unsigned long long)oi->ip_blkno, oi->ip_flags); >> - spin_unlock(&oi->ip_lock); >> status = -ENOENT; >> goto bail; >> } > > The patch is obviously OK but I don't see any deadlock. mlog() doesn't > take any locks? >I guess Shuning refers the calling of printk with spin lock.> > _______________________________________________ > Ocfs2-devel mailing list > Ocfs2-devel at oss.oracle.com > https://oss.oracle.com/mailman/listinfo/ocfs2-devel >