@@ -1798,13 +1798,18 @@ static int build_dentry_path(struct dentry *dentry,
int *pfreepath)
{
char *path;
+ struct inode *dir;
- if (ceph_snap(d_inode(dentry->d_parent)) == CEPH_NOSNAP) {
- *pino = ceph_ino(d_inode(dentry->d_parent));
+ rcu_read_lock();
+ dir = d_inode_rcu(dentry->d_parent);
+ if (dir && ceph_snap(dir) == CEPH_NOSNAP) {
+ *pino = ceph_ino(dir);
+ rcu_read_unlock();
*ppath = dentry->d_name.name;
*ppathlen = dentry->d_name.len;
return 0;
}
+ rcu_read_unlock();
path = ceph_mdsc_build_path(dentry, ppathlen, pino, 1);
if (IS_ERR(path))
return PTR_ERR(path);
While we hold a reference to the dentry when build_dentry_path is called, we could end up racing with a rename that changes d_parent. Handle that situation correctly, by using the rcu_read_lock to ensure that the parent dentry and inode stick around long enough to safely check ceph_snap and ceph_ino. Link: http://tracker.ceph.com/issues/18148 Signed-off-by: Jeff Layton <jlayton@redhat.com> --- fs/ceph/mds_client.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)