From 196b87e5c00ce021e164a5de0f0d04f4116a9160 Mon Sep 17 00:00:00 2001 From: Xiubo Li Date: Fri, 17 Nov 2023 13:26:18 +0800 Subject: [PATCH] ceph: fix deadlock or deadcode of misusing dget() [ Upstream commit b493ad718b1f0357394d2cdecbf00a44a36fa085 ] The lock order is incorrect between denty and its parent, we should always make sure that the parent get the lock first. But since this deadcode is never used and the parent dir will always be set from the callers, let's just remove it. Link: https://lore.kernel.org/r/20231116081919.GZ1957730@ZenIV Reported-by: Al Viro Signed-off-by: Xiubo Li Reviewed-by: Jeff Layton Signed-off-by: Ilya Dryomov Signed-off-by: Sasha Levin --- fs/ceph/caps.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index 14215ec646f7..7f7e5f5d643c 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -4780,12 +4780,14 @@ int ceph_encode_dentry_release(void **p, struct dentry *dentry, struct inode *dir, int mds, int drop, int unless) { - struct dentry *parent = NULL; struct ceph_mds_request_release *rel = *p; struct ceph_dentry_info *di = ceph_dentry(dentry); int force = 0; int ret; + /* This shouldn't happen */ + BUG_ON(!dir); + /* * force an record for the directory caps if we have a dentry lease. * this is racy (can't take i_ceph_lock and d_lock together), but it @@ -4795,14 +4797,9 @@ int ceph_encode_dentry_release(void **p, struct dentry *dentry, spin_lock(&dentry->d_lock); if (di->lease_session && di->lease_session->s_mds == mds) force = 1; - if (!dir) { - parent = dget(dentry->d_parent); - dir = d_inode(parent); - } spin_unlock(&dentry->d_lock); ret = ceph_encode_inode_release(p, dir, mds, drop, unless, force); - dput(parent); spin_lock(&dentry->d_lock); if (ret && di->lease_session && di->lease_session->s_mds == mds) {