提交 5b83d2c5 编写于 作者: R Ram Pai 提交者: Linus Torvalds

[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: NRam Pai <linuxram@us.ibm.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
上级 b58fed8b
...@@ -650,7 +650,6 @@ static int graft_tree(struct vfsmount *mnt, struct nameidata *nd) ...@@ -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) ...@@ -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, ...@@ -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);
......
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