ceph: protect access to d_parent
d_parent is protected by d_lock: use it when looking up a dentry's parent
directory inode. Also take a reference and drop it in the caller to avoid
a use-after-free.
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index f34d47d..45fbd69 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -122,7 +122,7 @@
struct ceph_mds_client *mdsc = fsc->mdsc;
struct ceph_mds_request *req;
struct ceph_file_info *cf = file->private_data;
- struct inode *parent_inode = file->f_dentry->d_parent->d_inode;
+ struct inode *parent_inode = NULL;
int err;
int flags, fmode, wanted;
@@ -194,8 +194,10 @@
req->r_inode = inode;
ihold(inode);
req->r_num_caps = 1;
- err = ceph_mdsc_do_request(mdsc, (flags & (O_CREAT|O_TRUNC)) ?
- parent_inode : NULL, req);
+ if (flags & (O_CREAT|O_TRUNC))
+ parent_inode = ceph_get_dentry_parent_inode(file->f_dentry);
+ err = ceph_mdsc_do_request(mdsc, parent_inode, req);
+ iput(parent_inode);
if (!err)
err = ceph_init_file(inode, file, req->r_fmode);
ceph_mdsc_put_request(req);