On Tue, 2020-04-28 at 21:13 +0800, Wu Bo wrote: > if the ceph_mdsc_open_export_target_session() return fails, > should add a lock to avoid twice unlocking. > Because the lock will be released at the retry or out_unlock tag. >
The problem looks real, but... > -- > v1 -> v2: > add spin_lock(&ci->i_ceph_lock) before goto out_unlock tag. > > Signed-off-by: Wu Bo <[email protected]> > --- > fs/ceph/caps.c | 27 +++++++++++++++------------ > 1 file changed, 15 insertions(+), 12 deletions(-) > > diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c > index 185db76..414c0e2 100644 > --- a/fs/ceph/caps.c > +++ b/fs/ceph/caps.c > @@ -3731,22 +3731,25 @@ static void handle_cap_export(struct inode *inode, > struct ceph_mds_caps *ex, > > /* open target session */ > tsession = ceph_mdsc_open_export_target_session(mdsc, target); > - if (!IS_ERR(tsession)) { > - if (mds > target) { > - mutex_lock(&session->s_mutex); > - mutex_lock_nested(&tsession->s_mutex, > - SINGLE_DEPTH_NESTING); > - } else { > - mutex_lock(&tsession->s_mutex); > - mutex_lock_nested(&session->s_mutex, > - SINGLE_DEPTH_NESTING); > - } > - new_cap = ceph_get_cap(mdsc, NULL); > - } else { > + if (IS_ERR(tsession)) { > WARN_ON(1); > tsession = NULL; > target = -1; > + mutex_lock(&session->s_mutex); > + spin_lock(&ci->i_ceph_lock); > + goto out_unlock; Why did you make this case goto out_unlock instead of retrying as it did before? > + } > + > + if (mds > target) { > + mutex_lock(&session->s_mutex); > + mutex_lock_nested(&tsession->s_mutex, > + SINGLE_DEPTH_NESTING); > + } else { > + mutex_lock(&tsession->s_mutex); > + mutex_lock_nested(&session->s_mutex, > + SINGLE_DEPTH_NESTING); > } > + new_cap = ceph_get_cap(mdsc, NULL); > goto retry; > > out_unlock: -- Jeff Layton <[email protected]>
