From 4ac9137858e08a19f29feac4e1f4df7c268b0ba5 Mon Sep 17 00:00:00 2001 From: Jan Blunck Date: Thu, 14 Feb 2008 19:34:32 -0800 Subject: Embed a struct path into struct nameidata instead of nd->{dentry,mnt} This is the central patch of a cleanup series. In most cases there is no good reason why someone would want to use a dentry for itself. This series reflects that fact and embeds a struct path into nameidata. Together with the other patches of this series - it enforced the correct order of getting/releasing the reference count on pairs - it prepares the VFS for stacking support since it is essential to have a struct path in every place where the stack can be traversed - it reduces the overall code size: without patch series: text data bss dec hex filename 5321639 858418 715768 6895825 6938d1 vmlinux with patch series: text data bss dec hex filename 5320026 858418 715768 6894212 693284 vmlinux This patch: Switch from nd->{dentry,mnt} to nd->path.{dentry,mnt} everywhere. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix cifs] [akpm@linux-foundation.org: fix smack] Signed-off-by: Jan Blunck Signed-off-by: Andreas Gruenbacher Acked-by: Christoph Hellwig Cc: Al Viro Cc: Casey Schaufler Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/namespace.c | 185 ++++++++++++++++++++++++++++++--------------------------- 1 file changed, 98 insertions(+), 87 deletions(-) (limited to 'fs/namespace.c') diff --git a/fs/namespace.c b/fs/namespace.c index 7937d30a6732..5d9fd4c6d1f5 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -157,13 +157,13 @@ static void __touch_mnt_namespace(struct mnt_namespace *ns) static void detach_mnt(struct vfsmount *mnt, struct nameidata *old_nd) { - old_nd->dentry = mnt->mnt_mountpoint; - old_nd->mnt = mnt->mnt_parent; + old_nd->path.dentry = mnt->mnt_mountpoint; + old_nd->path.mnt = mnt->mnt_parent; mnt->mnt_parent = mnt; mnt->mnt_mountpoint = mnt->mnt_root; list_del_init(&mnt->mnt_child); list_del_init(&mnt->mnt_hash); - old_nd->dentry->d_mounted--; + old_nd->path.dentry->d_mounted--; } void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry, @@ -176,10 +176,10 @@ void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry, static void attach_mnt(struct vfsmount *mnt, struct nameidata *nd) { - mnt_set_mountpoint(nd->mnt, nd->dentry, mnt); + mnt_set_mountpoint(nd->path.mnt, nd->path.dentry, mnt); list_add_tail(&mnt->mnt_hash, mount_hashtable + - hash(nd->mnt, nd->dentry)); - list_add_tail(&mnt->mnt_child, &nd->mnt->mnt_mounts); + hash(nd->path.mnt, nd->path.dentry)); + list_add_tail(&mnt->mnt_child, &nd->path.mnt->mnt_mounts); } /* @@ -679,20 +679,20 @@ asmlinkage long sys_umount(char __user * name, int flags) if (retval) goto out; retval = -EINVAL; - if (nd.dentry != nd.mnt->mnt_root) + if (nd.path.dentry != nd.path.mnt->mnt_root) goto dput_and_out; - if (!check_mnt(nd.mnt)) + if (!check_mnt(nd.path.mnt)) goto dput_and_out; retval = -EPERM; if (!capable(CAP_SYS_ADMIN)) goto dput_and_out; - retval = do_umount(nd.mnt, flags); + retval = do_umount(nd.path.mnt, flags); dput_and_out: /* we mustn't call path_put() as that would clear mnt_expiry_mark */ - dput(nd.dentry); - mntput_no_expire(nd.mnt); + dput(nd.path.dentry); + mntput_no_expire(nd.path.mnt); out: return retval; } @@ -715,10 +715,10 @@ static int mount_is_safe(struct nameidata *nd) return 0; return -EPERM; #ifdef notyet - if (S_ISLNK(nd->dentry->d_inode->i_mode)) + if (S_ISLNK(nd->path.dentry->d_inode->i_mode)) return -EPERM; - if (nd->dentry->d_inode->i_mode & S_ISVTX) { - if (current->uid != nd->dentry->d_inode->i_uid) + if (nd->path.dentry->d_inode->i_mode & S_ISVTX) { + if (current->uid != nd->path.dentry->d_inode->i_uid) return -EPERM; } if (vfs_permission(nd, MAY_WRITE)) @@ -767,8 +767,8 @@ struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry, q = q->mnt_parent; } p = s; - nd.mnt = q; - nd.dentry = p->mnt_mountpoint; + nd.path.mnt = q; + nd.path.dentry = p->mnt_mountpoint; q = clone_mnt(p, p->mnt_root, flag); if (!q) goto Enomem; @@ -877,8 +877,8 @@ static int attach_recursive_mnt(struct vfsmount *source_mnt, struct nameidata *nd, struct nameidata *parent_nd) { LIST_HEAD(tree_list); - struct vfsmount *dest_mnt = nd->mnt; - struct dentry *dest_dentry = nd->dentry; + struct vfsmount *dest_mnt = nd->path.mnt; + struct dentry *dest_dentry = nd->path.dentry; struct vfsmount *child, *p; if (propagate_mnt(dest_mnt, dest_dentry, source_mnt, &tree_list)) @@ -913,13 +913,13 @@ static int graft_tree(struct vfsmount *mnt, struct nameidata *nd) if (mnt->mnt_sb->s_flags & MS_NOUSER) return -EINVAL; - if (S_ISDIR(nd->dentry->d_inode->i_mode) != + if (S_ISDIR(nd->path.dentry->d_inode->i_mode) != S_ISDIR(mnt->mnt_root->d_inode->i_mode)) return -ENOTDIR; err = -ENOENT; - mutex_lock(&nd->dentry->d_inode->i_mutex); - if (IS_DEADDIR(nd->dentry->d_inode)) + mutex_lock(&nd->path.dentry->d_inode->i_mutex); + if (IS_DEADDIR(nd->path.dentry->d_inode)) goto out_unlock; err = security_sb_check_sb(mnt, nd); @@ -927,10 +927,10 @@ static int graft_tree(struct vfsmount *mnt, struct nameidata *nd) goto out_unlock; err = -ENOENT; - if (IS_ROOT(nd->dentry) || !d_unhashed(nd->dentry)) + if (IS_ROOT(nd->path.dentry) || !d_unhashed(nd->path.dentry)) err = attach_recursive_mnt(mnt, nd, NULL); out_unlock: - mutex_unlock(&nd->dentry->d_inode->i_mutex); + mutex_unlock(&nd->path.dentry->d_inode->i_mutex); if (!err) security_sb_post_addmount(mnt, nd); return err; @@ -942,14 +942,14 @@ out_unlock: */ static noinline int do_change_type(struct nameidata *nd, int flag) { - struct vfsmount *m, *mnt = nd->mnt; + struct vfsmount *m, *mnt = nd->path.mnt; int recurse = flag & MS_REC; int type = flag & ~MS_REC; if (!capable(CAP_SYS_ADMIN)) return -EPERM; - if (nd->dentry != nd->mnt->mnt_root) + if (nd->path.dentry != nd->path.mnt->mnt_root) return -EINVAL; down_write(&namespace_sem); @@ -981,17 +981,17 @@ static noinline int do_loopback(struct nameidata *nd, char *old_name, down_write(&namespace_sem); err = -EINVAL; - if (IS_MNT_UNBINDABLE(old_nd.mnt)) - goto out; + if (IS_MNT_UNBINDABLE(old_nd.path.mnt)) + goto out; - if (!check_mnt(nd->mnt) || !check_mnt(old_nd.mnt)) + if (!check_mnt(nd->path.mnt) || !check_mnt(old_nd.path.mnt)) goto out; err = -ENOMEM; if (recurse) - mnt = copy_tree(old_nd.mnt, old_nd.dentry, 0); + mnt = copy_tree(old_nd.path.mnt, old_nd.path.dentry, 0); else - mnt = clone_mnt(old_nd.mnt, old_nd.dentry, 0); + mnt = clone_mnt(old_nd.path.mnt, old_nd.path.dentry, 0); if (!mnt) goto out; @@ -1021,24 +1021,24 @@ static noinline int do_remount(struct nameidata *nd, int flags, int mnt_flags, void *data) { int err; - struct super_block *sb = nd->mnt->mnt_sb; + struct super_block *sb = nd->path.mnt->mnt_sb; if (!capable(CAP_SYS_ADMIN)) return -EPERM; - if (!check_mnt(nd->mnt)) + if (!check_mnt(nd->path.mnt)) return -EINVAL; - if (nd->dentry != nd->mnt->mnt_root) + if (nd->path.dentry != nd->path.mnt->mnt_root) return -EINVAL; down_write(&sb->s_umount); err = do_remount_sb(sb, flags, data, 0); if (!err) - nd->mnt->mnt_flags = mnt_flags; + nd->path.mnt->mnt_flags = mnt_flags; up_write(&sb->s_umount); if (!err) - security_sb_post_remount(nd->mnt, flags, data); + security_sb_post_remount(nd->path.mnt, flags, data); return err; } @@ -1069,56 +1069,60 @@ static noinline int do_move_mount(struct nameidata *nd, char *old_name) return err; down_write(&namespace_sem); - while (d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry)) + while (d_mountpoint(nd->path.dentry) && + follow_down(&nd->path.mnt, &nd->path.dentry)) ; err = -EINVAL; - if (!check_mnt(nd->mnt) || !check_mnt(old_nd.mnt)) + if (!check_mnt(nd->path.mnt) || !check_mnt(old_nd.path.mnt)) goto out; err = -ENOENT; - mutex_lock(&nd->dentry->d_inode->i_mutex); - if (IS_DEADDIR(nd->dentry->d_inode)) + mutex_lock(&nd->path.dentry->d_inode->i_mutex); + if (IS_DEADDIR(nd->path.dentry->d_inode)) goto out1; - if (!IS_ROOT(nd->dentry) && d_unhashed(nd->dentry)) + if (!IS_ROOT(nd->path.dentry) && d_unhashed(nd->path.dentry)) goto out1; err = -EINVAL; - if (old_nd.dentry != old_nd.mnt->mnt_root) + if (old_nd.path.dentry != old_nd.path.mnt->mnt_root) goto out1; - if (old_nd.mnt == old_nd.mnt->mnt_parent) + if (old_nd.path.mnt == old_nd.path.mnt->mnt_parent) goto out1; - if (S_ISDIR(nd->dentry->d_inode->i_mode) != - S_ISDIR(old_nd.dentry->d_inode->i_mode)) + if (S_ISDIR(nd->path.dentry->d_inode->i_mode) != + S_ISDIR(old_nd.path.dentry->d_inode->i_mode)) goto out1; /* * Don't move a mount residing in a shared parent. */ - if (old_nd.mnt->mnt_parent && IS_MNT_SHARED(old_nd.mnt->mnt_parent)) + if (old_nd.path.mnt->mnt_parent && + IS_MNT_SHARED(old_nd.path.mnt->mnt_parent)) goto out1; /* * Don't move a mount tree containing unbindable mounts to a destination * mount which is shared. */ - if (IS_MNT_SHARED(nd->mnt) && tree_contains_unbindable(old_nd.mnt)) + if (IS_MNT_SHARED(nd->path.mnt) && + tree_contains_unbindable(old_nd.path.mnt)) goto out1; err = -ELOOP; - for (p = nd->mnt; p->mnt_parent != p; p = p->mnt_parent) - if (p == old_nd.mnt) + for (p = nd->path.mnt; p->mnt_parent != p; p = p->mnt_parent) + if (p == old_nd.path.mnt) goto out1; - if ((err = attach_recursive_mnt(old_nd.mnt, nd, &parent_nd))) + err = attach_recursive_mnt(old_nd.path.mnt, nd, &parent_nd); + if (err) goto out1; spin_lock(&vfsmount_lock); /* if the mount is moved, it should no longer be expire * automatically */ - list_del_init(&old_nd.mnt->mnt_expire); + list_del_init(&old_nd.path.mnt->mnt_expire); spin_unlock(&vfsmount_lock); out1: - mutex_unlock(&nd->dentry->d_inode->i_mutex); + mutex_unlock(&nd->path.dentry->d_inode->i_mutex); out: up_write(&namespace_sem); if (!err) @@ -1162,16 +1166,17 @@ int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd, down_write(&namespace_sem); /* Something was mounted here while we slept */ - while (d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry)) + while (d_mountpoint(nd->path.dentry) && + follow_down(&nd->path.mnt, &nd->path.dentry)) ; err = -EINVAL; - if (!check_mnt(nd->mnt)) + if (!check_mnt(nd->path.mnt)) goto unlock; /* Refuse the same filesystem on the same mount point */ err = -EBUSY; - if (nd->mnt->mnt_sb == newmnt->mnt_sb && - nd->mnt->mnt_root == nd->dentry) + if (nd->path.mnt->mnt_sb == newmnt->mnt_sb && + nd->path.mnt->mnt_root == nd->path.dentry) goto unlock; err = -EINVAL; @@ -1697,12 +1702,14 @@ static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd) if (fs) { atomic_inc(&fs->count); task_unlock(p); - if (fs->root == old_nd->dentry - && fs->rootmnt == old_nd->mnt) - set_fs_root(fs, new_nd->mnt, new_nd->dentry); - if (fs->pwd == old_nd->dentry - && fs->pwdmnt == old_nd->mnt) - set_fs_pwd(fs, new_nd->mnt, new_nd->dentry); + if (fs->root == old_nd->path.dentry + && fs->rootmnt == old_nd->path.mnt) + set_fs_root(fs, new_nd->path.mnt, + new_nd->path.dentry); + if (fs->pwd == old_nd->path.dentry + && fs->pwdmnt == old_nd->path.mnt) + set_fs_pwd(fs, new_nd->path.mnt, + new_nd->path.dentry); put_fs_struct(fs); } else task_unlock(p); @@ -1752,7 +1759,7 @@ asmlinkage long sys_pivot_root(const char __user * new_root, if (error) goto out0; error = -EINVAL; - if (!check_mnt(new_nd.mnt)) + if (!check_mnt(new_nd.path.mnt)) goto out1; error = __user_walk(put_old, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &old_nd); @@ -1766,55 +1773,59 @@ asmlinkage long sys_pivot_root(const char __user * new_root, } read_lock(¤t->fs->lock); - user_nd.mnt = mntget(current->fs->rootmnt); - user_nd.dentry = dget(current->fs->root); + user_nd.path.mnt = mntget(current->fs->rootmnt); + user_nd.path.dentry = dget(current->fs->root); read_unlock(¤t->fs->lock); down_write(&namespace_sem); - mutex_lock(&old_nd.dentry->d_inode->i_mutex); + mutex_lock(&old_nd.path.dentry->d_inode->i_mutex); error = -EINVAL; - if (IS_MNT_SHARED(old_nd.mnt) || - IS_MNT_SHARED(new_nd.mnt->mnt_parent) || - IS_MNT_SHARED(user_nd.mnt->mnt_parent)) + if (IS_MNT_SHARED(old_nd.path.mnt) || + IS_MNT_SHARED(new_nd.path.mnt->mnt_parent) || + IS_MNT_SHARED(user_nd.path.mnt->mnt_parent)) goto out2; - if (!check_mnt(user_nd.mnt)) + if (!check_mnt(user_nd.path.mnt)) goto out2; error = -ENOENT; - if (IS_DEADDIR(new_nd.dentry->d_inode)) + if (IS_DEADDIR(new_nd.path.dentry->d_inode)) goto out2; - if (d_unhashed(new_nd.dentry) && !IS_ROOT(new_nd.dentry)) + if (d_unhashed(new_nd.path.dentry) && !IS_ROOT(new_nd.path.dentry)) goto out2; - if (d_unhashed(old_nd.dentry) && !IS_ROOT(old_nd.dentry)) + if (d_unhashed(old_nd.path.dentry) && !IS_ROOT(old_nd.path.dentry)) goto out2; error = -EBUSY; - if (new_nd.mnt == user_nd.mnt || old_nd.mnt == user_nd.mnt) + if (new_nd.path.mnt == user_nd.path.mnt || + old_nd.path.mnt == user_nd.path.mnt) goto out2; /* loop, on the same file system */ error = -EINVAL; - if (user_nd.mnt->mnt_root != user_nd.dentry) + if (user_nd.path.mnt->mnt_root != user_nd.path.dentry) goto out2; /* not a mountpoint */ - if (user_nd.mnt->mnt_parent == user_nd.mnt) + if (user_nd.path.mnt->mnt_parent == user_nd.path.mnt) goto out2; /* not attached */ - if (new_nd.mnt->mnt_root != new_nd.dentry) + if (new_nd.path.mnt->mnt_root != new_nd.path.dentry) goto out2; /* not a mountpoint */ - if (new_nd.mnt->mnt_parent == new_nd.mnt) + if (new_nd.path.mnt->mnt_parent == new_nd.path.mnt) goto out2; /* not attached */ - tmp = old_nd.mnt; /* make sure we can reach put_old from new_root */ + /* make sure we can reach put_old from new_root */ + tmp = old_nd.path.mnt; spin_lock(&vfsmount_lock); - if (tmp != new_nd.mnt) { + if (tmp != new_nd.path.mnt) { for (;;) { if (tmp->mnt_parent == tmp) goto out3; /* already mounted on put_old */ - if (tmp->mnt_parent == new_nd.mnt) + if (tmp->mnt_parent == new_nd.path.mnt) break; tmp = tmp->mnt_parent; } - if (!is_subdir(tmp->mnt_mountpoint, new_nd.dentry)) + if (!is_subdir(tmp->mnt_mountpoint, new_nd.path.dentry)) goto out3; - } else if (!is_subdir(old_nd.dentry, new_nd.dentry)) + } else if (!is_subdir(old_nd.path.dentry, new_nd.path.dentry)) goto out3; - detach_mnt(new_nd.mnt, &parent_nd); - detach_mnt(user_nd.mnt, &root_parent); - attach_mnt(user_nd.mnt, &old_nd); /* mount old root on put_old */ - attach_mnt(new_nd.mnt, &root_parent); /* mount new_root on / */ + detach_mnt(new_nd.path.mnt, &parent_nd); + detach_mnt(user_nd.path.mnt, &root_parent); + /* mount old root on put_old */ + attach_mnt(user_nd.path.mnt, &old_nd); + /* mount new_root on / */ + attach_mnt(new_nd.path.mnt, &root_parent); touch_mnt_namespace(current->nsproxy->mnt_ns); spin_unlock(&vfsmount_lock); chroot_fs_refs(&user_nd, &new_nd); @@ -1823,7 +1834,7 @@ asmlinkage long sys_pivot_root(const char __user * new_root, path_release(&root_parent); path_release(&parent_nd); out2: - mutex_unlock(&old_nd.dentry->d_inode->i_mutex); + mutex_unlock(&old_nd.path.dentry->d_inode->i_mutex); up_write(&namespace_sem); path_release(&user_nd); path_release(&old_nd); -- cgit v1.2.3