[PATCH 8/8] ceph: hold i_ceph_lock when removing caps for freeing inode

[Yan, Zheng]

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

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: "Yan, Zheng" <zyan@xxxxxxxxxx>
---
 fs/ceph/caps.c  | 10 ++++++----
 fs/ceph/inode.c |  2 +-
 fs/ceph/super.h |  2 +-
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 0176241eaea7..7754d7679122 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1263,20 +1263,22 @@ static int send_cap_msg(struct cap_msg_args *arg)
 }
 
 /*
- * 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_remove_caps(struct inode *inode)
+void __ceph_remove_caps(struct ceph_inode_info *ci)
 {
-	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);
 }
 
 /*
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index e47a25495be5..30d0cdc21035 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -534,7 +534,7 @@ void ceph_destroy_inode(struct inode *inode)
 
 	ceph_fscache_unregister_inode_cookie(ci);
 
-	__ceph_remove_caps(inode);
+	__ceph_remove_caps(ci);
 
 	if (__ceph_has_any_quota(ci))
 		ceph_adjust_quota_realms_count(inode, false);
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 11aeb540b0cf..e74867743e07 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -1003,7 +1003,7 @@ extern void ceph_add_cap(struct inode *inode,
 			 unsigned cap, unsigned seq, u64 realmino, int flags,
 			 struct ceph_cap **new_cap);
 extern void __ceph_remove_cap(struct ceph_cap *cap, bool queue_release);
-extern void __ceph_remove_caps(struct inode* inode);
+extern void __ceph_remove_caps(struct ceph_inode_info *ci);
 extern void ceph_put_cap(struct ceph_mds_client *mdsc,
 			 struct ceph_cap *cap);
 extern int ceph_is_any_caps(struct inode *inode);
-- 
2.17.2