[PATCH 5.2 20/20] ceph: hold i_ceph_lock when removing caps for freeing inode

Greg Kroah-Hartman
2019-08-02T09:58:37Z

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 | 10 ++++++----
fs/ceph/inode.c | 2 +-
fs/ceph/super.h | 2 +-
3 files changed, 8 insertions(+), 6 deletions(-)

--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1263,20 +1263,22 @@ 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_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);
}

/*
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -536,7 +536,7 @@ void ceph_evict_inode(struct inode *inod

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);
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -1000,7 +1000,7 @@ extern void ceph_add_cap(struct inode *i
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);