[PATCH 4.19 30/32] ceph: hold i_ceph_lock when removing caps for freeing inode

Greg Kroah-Hartman
2019-08-02T09:57:16Z

From: Yan, Zheng <zyan@redhat.com>

commit d6e47819721ae2d9d090058ad5570a66f3c42e39 upstream.

ceph_d_revalidate(, LOOKUP_RCU) may call __ceph_caps_issued_mask()
on a freeing inode.

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/ceph/caps.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1237,20 +1237,23 @@ static int send_cap_msg(struct cap_msg_a
}

/*
- * Queue cap releases when an inode is dropped from our cache. Since
- * inode is about to be destroyed, there is no need for i_ceph_lock.
+ * Queue cap releases when an inode is dropped from our cache.
*/
void ceph_queue_caps_release(struct inode *inode)
{
struct ceph_inode_info *ci = ceph_inode(inode);
struct rb_node *p;

+ /* lock i_ceph_lock, because ceph_d_revalidate(..., LOOKUP_RCU)
+ * may call __ceph_caps_issued_mask() on a freeing inode. */
+ spin_lock(&ci->i_ceph_lock);
p = rb_first(&ci->i_caps);
while (p) {
struct ceph_cap *cap = rb_entry(p, struct ceph_cap, ci_node);
p = rb_next(p);
__ceph_remove_cap(cap, true);
}
+ spin_unlock(&ci->i_ceph_lock);
}

/*