Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762483AbYBEVj7 (ORCPT ); Tue, 5 Feb 2008 16:39:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761682AbYBEVhy (ORCPT ); Tue, 5 Feb 2008 16:37:54 -0500 Received: from fxip-0047f.externet.hu ([88.209.222.127]:38771 "EHLO pomaz-ex.szeredi.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761627AbYBEVhr (ORCPT ); Tue, 5 Feb 2008 16:37:47 -0500 Message-Id: <20080205213659.136906881@szeredi.hu> References: <20080205213616.343721693@szeredi.hu> User-Agent: quilt/0.45-1 Date: Tue, 05 Feb 2008 22:36:19 +0100 From: Miklos Szeredi To: akpm@linux-foundation.org, hch@infradead.org, serue@us.ibm.com Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [patch 03/10] unprivileged mounts: propagate error values from clone_mnt Content-Disposition: inline; filename=unprivileged-mounts-propagate-error-values-from-clone_mnt.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5641 Lines: 189 From: Miklos Szeredi Allow clone_mnt() to return errors other than ENOMEM. This will be used for returning a different error value when the number of user mounts goes over the limit. Fix copy_tree() to return EPERM for unbindable mounts. Signed-off-by: Miklos Szeredi Acked-by: Serge Hallyn --- Index: linux/fs/namespace.c =================================================================== --- linux.orig/fs/namespace.c 2008-02-04 23:47:53.000000000 +0100 +++ linux/fs/namespace.c 2008-02-04 23:47:56.000000000 +0100 @@ -524,41 +524,42 @@ static struct vfsmount *clone_mnt(struct struct super_block *sb = old->mnt_sb; struct vfsmount *mnt = alloc_vfsmnt(old->mnt_devname); - if (mnt) { - mnt->mnt_flags = old->mnt_flags; - atomic_inc(&sb->s_active); - mnt->mnt_sb = sb; - mnt->mnt_root = dget(root); - mnt->mnt_mountpoint = mnt->mnt_root; - mnt->mnt_parent = mnt; - - /* don't copy the MNT_USER flag */ - mnt->mnt_flags &= ~MNT_USER; - if (flag & CL_SETUSER) - set_mnt_user(mnt); - - if (flag & CL_SLAVE) { - list_add(&mnt->mnt_slave, &old->mnt_slave_list); - mnt->mnt_master = old; - CLEAR_MNT_SHARED(mnt); - } else if (!(flag & CL_PRIVATE)) { - if ((flag & CL_PROPAGATION) || IS_MNT_SHARED(old)) - list_add(&mnt->mnt_share, &old->mnt_share); - if (IS_MNT_SLAVE(old)) - list_add(&mnt->mnt_slave, &old->mnt_slave); - mnt->mnt_master = old->mnt_master; - } - if (flag & CL_MAKE_SHARED) - set_mnt_shared(mnt); + if (!mnt) + return ERR_PTR(-ENOMEM); - /* stick the duplicate mount on the same expiry list - * as the original if that was on one */ - if (flag & CL_EXPIRE) { - spin_lock(&vfsmount_lock); - if (!list_empty(&old->mnt_expire)) - list_add(&mnt->mnt_expire, &old->mnt_expire); - spin_unlock(&vfsmount_lock); - } + mnt->mnt_flags = old->mnt_flags; + atomic_inc(&sb->s_active); + mnt->mnt_sb = sb; + mnt->mnt_root = dget(root); + mnt->mnt_mountpoint = mnt->mnt_root; + mnt->mnt_parent = mnt; + + /* don't copy the MNT_USER flag */ + mnt->mnt_flags &= ~MNT_USER; + if (flag & CL_SETUSER) + set_mnt_user(mnt); + + if (flag & CL_SLAVE) { + list_add(&mnt->mnt_slave, &old->mnt_slave_list); + mnt->mnt_master = old; + CLEAR_MNT_SHARED(mnt); + } else if (!(flag & CL_PRIVATE)) { + if ((flag & CL_PROPAGATION) || IS_MNT_SHARED(old)) + list_add(&mnt->mnt_share, &old->mnt_share); + if (IS_MNT_SLAVE(old)) + list_add(&mnt->mnt_slave, &old->mnt_slave); + mnt->mnt_master = old->mnt_master; + } + if (flag & CL_MAKE_SHARED) + set_mnt_shared(mnt); + + /* stick the duplicate mount on the same expiry list + * as the original if that was on one */ + if (flag & CL_EXPIRE) { + spin_lock(&vfsmount_lock); + if (!list_empty(&old->mnt_expire)) + list_add(&mnt->mnt_expire, &old->mnt_expire); + spin_unlock(&vfsmount_lock); } return mnt; } @@ -1137,11 +1138,11 @@ struct vfsmount *copy_tree(struct vfsmou struct nameidata nd; if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(mnt)) - return NULL; + return ERR_PTR(-EPERM); res = q = clone_mnt(mnt, dentry, flag); - if (!q) - goto Enomem; + if (IS_ERR(q)) + goto error; q->mnt_mountpoint = mnt->mnt_mountpoint; p = mnt; @@ -1162,8 +1163,8 @@ struct vfsmount *copy_tree(struct vfsmou nd.path.mnt = q; nd.path.dentry = p->mnt_mountpoint; q = clone_mnt(p, p->mnt_root, flag); - if (!q) - goto Enomem; + if (IS_ERR(q)) + goto error; spin_lock(&vfsmount_lock); list_add_tail(&q->mnt_list, &res->mnt_list); attach_mnt(q, &nd); @@ -1171,7 +1172,7 @@ struct vfsmount *copy_tree(struct vfsmou } } return res; -Enomem: + error: if (res) { LIST_HEAD(umount_list); spin_lock(&vfsmount_lock); @@ -1179,7 +1180,7 @@ Enomem: spin_unlock(&vfsmount_lock); release_mounts(&umount_list); } - return NULL; + return q; } struct vfsmount *collect_mounts(struct vfsmount *mnt, struct dentry *dentry) @@ -1378,13 +1379,13 @@ static int do_loopback(struct nameidata goto out; clone_fl = (flags & MS_SETUSER) ? CL_SETUSER : 0; - err = -ENOMEM; if (flags & MS_REC) mnt = copy_tree(old_nd.path.mnt, old_nd.path.dentry, clone_fl); else mnt = clone_mnt(old_nd.path.mnt, old_nd.path.dentry, clone_fl); - if (!mnt) + err = PTR_ERR(mnt); + if (IS_ERR(mnt)) goto out; err = graft_tree(mnt, nd); @@ -1955,10 +1956,10 @@ static struct mnt_namespace *dup_mnt_ns( /* First pass: copy the tree topology */ new_ns->root = copy_tree(mnt_ns->root, mnt_ns->root->mnt_root, CL_COPY_ALL | CL_EXPIRE); - if (!new_ns->root) { + if (IS_ERR(new_ns->root)) { up_write(&namespace_sem); kfree(new_ns); - return ERR_PTR(-ENOMEM);; + return ERR_CAST(new_ns->root); } spin_lock(&vfsmount_lock); list_add_tail(&new_ns->list, &new_ns->root->mnt_list); Index: linux/fs/pnode.c =================================================================== --- linux.orig/fs/pnode.c 2008-02-04 23:47:47.000000000 +0100 +++ linux/fs/pnode.c 2008-02-04 23:47:56.000000000 +0100 @@ -224,8 +224,9 @@ int propagate_mnt(struct vfsmount *dest_ source = get_source(m, prev_dest_mnt, prev_src_mnt, &type); - if (!(child = copy_tree(source, source->mnt_root, type))) { - ret = -ENOMEM; + child = copy_tree(source, source->mnt_root, type); + if (IS_ERR(child)) { + ret = PTR_ERR(child); list_splice(tree_list, tmp_list.prev); goto out; } -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/