This is a note to let you know that I've just added the patch titled
ceph: fix deadlock or deadcode of misusing dget()
to the 6.7-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ceph-fix-deadlock-or-deadcode-of-misusing-dget.patch
and it can be found in the queue-6.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 40ee700bda78be63c1c5159af7c088b3df1b0d1a
Author: Xiubo Li <xiubli@xxxxxxxxxx>
Date: Fri Nov 17 13:26:18 2023 +0800
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 <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 2c0b8dc3dd0d..9c02f328c966 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -4887,13 +4887,15 @@ 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);
struct ceph_client *cl;
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
@@ -4903,14 +4905,9 @@ 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);
cl = ceph_inode_to_client(dir);
spin_lock(&dentry->d_lock);
