FAILED: patch "[PATCH] ovl: let helper ovl_i_path_real() return the realinode" failed to apply to 5.15-stable tree

FAILED: patch "[PATCH] ovl: let helper ovl_i_path_real() return the realinode" failed to apply to 5.15-stable tree

[gregkh]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x b2dd05f107b11966e26fe52a313b418364cf497b
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2023071608-regain-untapped-0931@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

b2dd05f107b1 ("ovl: let helper ovl_i_path_real() return the realinode")
e67fe63341b8 ("fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap")
9452e93e6dae ("fs: port privilege checking helpers to mnt_idmap")
f2d40141d5d9 ("fs: port inode_init_owner() to mnt_idmap")
4609e1f18e19 ("fs: port ->permission() to pass mnt_idmap")
13e83a4923be ("fs: port ->set_acl() to pass mnt_idmap")
77435322777d ("fs: port ->get_acl() to pass mnt_idmap")
011e2b717b1b ("fs: port ->tmpfile() to pass mnt_idmap")
5ebb29bee8d5 ("fs: port ->mknod() to pass mnt_idmap")
c54bd91e9eab ("fs: port ->mkdir() to pass mnt_idmap")
7a77db95511c ("fs: port ->symlink() to pass mnt_idmap")
6c960e68aaed ("fs: port ->create() to pass mnt_idmap")
b74d24f7a74f ("fs: port ->getattr() to pass mnt_idmap")
c1632a0f1120 ("fs: port ->setattr() to pass mnt_idmap")
abf08576afe3 ("fs: port vfs_*() helpers to struct mnt_idmap")
6022ec6ee2c3 ("Merge tag 'ntfs3_for_6.2' of https://github.com/Paragon-Software-Group/linux-ntfs3")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b2dd05f107b11966e26fe52a313b418364cf497b Mon Sep 17 00:00:00 2001
From: Zhihao Cheng <chengzhihao1@huawei.com>
Date: Tue, 16 May 2023 22:16:17 +0800
Subject: [PATCH] ovl: let helper ovl_i_path_real() return the realinode

Let helper ovl_i_path_real() return the realinode to prepare for
checking non-null realinode in RCU walking path.

[msz] Use d_inode_rcu() since we are depending on the consitency
between dentry and inode being non-NULL in an RCU setting.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Fixes: ffa5723c6d25 ("ovl: store lower path in ovl_inode")
Cc: <stable@vger.kernel.org> # v5.19
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 4d0b278f5630..7398de332527 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -382,7 +382,7 @@ enum ovl_path_type ovl_path_type(struct dentry *dentry);
 void ovl_path_upper(struct dentry *dentry, struct path *path);
 void ovl_path_lower(struct dentry *dentry, struct path *path);
 void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
-void ovl_i_path_real(struct inode *inode, struct path *path);
+struct inode *ovl_i_path_real(struct inode *inode, struct path *path);
 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
 enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path);
 struct dentry *ovl_dentry_upper(struct dentry *dentry);
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 923d66d131c1..5a6f34c7ed03 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -250,7 +250,7 @@ struct dentry *ovl_i_dentry_upper(struct inode *inode)
 	return ovl_upperdentry_dereference(OVL_I(inode));
 }
 
-void ovl_i_path_real(struct inode *inode, struct path *path)
+struct inode *ovl_i_path_real(struct inode *inode, struct path *path)
 {
 	path->dentry = ovl_i_dentry_upper(inode);
 	if (!path->dentry) {
@@ -259,6 +259,8 @@ void ovl_i_path_real(struct inode *inode, struct path *path)
 	} else {
 		path->mnt = ovl_upper_mnt(OVL_FS(inode->i_sb));
 	}
+
+	return path->dentry ? d_inode_rcu(path->dentry) : NULL;
 }
 
 struct inode *ovl_inode_upper(struct inode *inode)
@@ -1105,8 +1107,7 @@ void ovl_copyattr(struct inode *inode)
 	vfsuid_t vfsuid;
 	vfsgid_t vfsgid;
 
-	ovl_i_path_real(inode, &realpath);
-	realinode = d_inode(realpath.dentry);
+	realinode = ovl_i_path_real(inode, &realpath);
 	real_idmap = mnt_idmap(realpath.mnt);
 
 	vfsuid = i_uid_into_vfsuid(real_idmap, realinode);