From: Al Viro <viro@zeniv.linux.org.uk>
Date: Fri, 25 Apr 2025 16:55:39 +0000 (-0400)
Subject: do_move_mount(): take dropping the old mountpoint into attach_recursive_mnt()
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=761de25854424aa23fd1d7b2bef5c7d184690926;p=thirdparty%2Fkernel%2Flinux.git

do_move_mount(): take dropping the old mountpoint into attach_recursive_mnt()

... and fold it with unhash_mnt() there - there's no need to retain a reference
to old_mp beyond that point, since by then all mountpoints we were going to add
are either explicitly pinned by get_mountpoint() or have stuff already added
to them.

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---

diff --git a/fs/namespace.c b/fs/namespace.c
index adb37f06ba689..e5f8fde57c997 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2682,7 +2682,7 @@ static int attach_recursive_mnt(struct mount *source_mnt,
 	}
 
 	if (moving) {
-		unhash_mnt(source_mnt);
+		umount_mnt(source_mnt);
 		mnt_notify_add(source_mnt);
 	} else {
 		if (source_mnt->mnt_ns) {
@@ -3598,7 +3598,7 @@ static int do_move_mount(struct path *old_path,
 	struct mount *p;
 	struct mount *old;
 	struct mount *parent;
-	struct mountpoint *mp, *old_mp;
+	struct mountpoint *mp;
 	int err;
 	bool attached, beneath = flags & MNT_TREE_BENEATH;
 
@@ -3610,7 +3610,6 @@ static int do_move_mount(struct path *old_path,
 	p = real_mount(new_path->mnt);
 	parent = old->mnt_parent;
 	attached = mnt_has_parent(old);
-	old_mp = old->mnt_mp;
 	ns = old->mnt_ns;
 
 	err = -EINVAL;
@@ -3684,8 +3683,6 @@ static int do_move_mount(struct path *old_path,
 	/* if the mount is moved, it should no longer be expire
 	 * automatically */
 	list_del_init(&old->mnt_expire);
-	if (attached)
-		put_mountpoint(old_mp);
 out:
 	unlock_mount(mp);
 	if (!err) {