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Commit 5b83d2c5 authored by Ram Pai's avatar Ram Pai Committed by Linus Torvalds
Browse files

[PATCH] sanitize the interface of graft_tree(). 



Old semantics: graft_tree() grabs a reference on the vfsmount before
returning success.

New one: graft_tree() leaves that to caller.

All the callers of graft_tree() immediately dropped that reference
anyway.  Changing the interface takes care of this unnecessary overhead.

Idea proposed by Al Viro.

Signed-off-by: default avatarRam Pai <linuxram@us.ibm.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent b58fed8b

fs/namespace.c

+6 −6
Original line number Original line Diff line number Diff line
@@ -650,7 +650,6 @@ static int graft_tree(struct vfsmount *mnt, struct nameidata *nd) 
		attach_mnt(mnt, nd);

		attach_mnt(mnt, nd);

		list_add_tail(&head, &mnt->mnt_list);

		list_add_tail(&head, &mnt->mnt_list);

		list_splice(&head, current->namespace->list.prev);

		list_splice(&head, current->namespace->list.prev);

		mntget(mnt);

		err = 0;

		err = 0;

		touch_namespace(current->namespace);

		touch_namespace(current->namespace);

	}

	}
@@ -702,8 +701,7 @@ static int do_loopback(struct nameidata *nd, char *old_name, int recurse) 
		spin_lock(&vfsmount_lock);

		spin_lock(&vfsmount_lock);

		umount_tree(mnt);

		umount_tree(mnt);

		spin_unlock(&vfsmount_lock);

		spin_unlock(&vfsmount_lock);

	} else

	}

		mntput(mnt);





out:

out:

	up_write(&current->namespace->sem);

	up_write(&current->namespace->sem);
@@ -857,15 +855,17 @@ int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd, 
		goto unlock;

		goto unlock;





	newmnt->mnt_flags = mnt_flags;

	newmnt->mnt_flags = mnt_flags;

	newmnt->mnt_namespace = current->namespace;

	if ((err = graft_tree(newmnt, nd)))

	err = graft_tree(newmnt, nd);

		goto unlock;





	if (err == 0 && fslist) {

	if (fslist) {

		/* add to the specified expiration list */

		/* add to the specified expiration list */

		spin_lock(&vfsmount_lock);

		spin_lock(&vfsmount_lock);

		list_add_tail(&newmnt->mnt_expire, fslist);

		list_add_tail(&newmnt->mnt_expire, fslist);

		spin_unlock(&vfsmount_lock);

		spin_unlock(&vfsmount_lock);

	}

	}

	up_write(&current->namespace->sem);

	return 0;





unlock:

unlock:

	up_write(&current->namespace->sem);

	up_write(&current->namespace->sem);