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[PATCH] get rid of more nameidata passing in namespace.c 

Further reduction of stack footprint (sys_pivot_root());
lose useless BKL in there, while we are at it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2008-03-22 18:00:39 -04:00
parent b5266eb4c8
commit 8c3ee42e80
1 changed files with 25 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

53
fs/namespace.c
View File

@ -1205,32 +1205,32 @@ static int attach_recursive_mnt(struct vfsmount *source_mnt,
return 0;
}
static int graft_tree(struct vfsmount *mnt, struct nameidata *nd)
static int graft_tree(struct vfsmount *mnt, struct path *path)
{
int err;
if (mnt->mnt_sb->s_flags & MS_NOUSER)
return -EINVAL;
if (S_ISDIR(nd->path.dentry->d_inode->i_mode) !=
if (S_ISDIR(path->dentry->d_inode->i_mode) !=
S_ISDIR(mnt->mnt_root->d_inode->i_mode))
return -ENOTDIR;
err = -ENOENT;
mutex_lock(&nd->path.dentry->d_inode->i_mutex);
if (IS_DEADDIR(nd->path.dentry->d_inode))
mutex_lock(&path->dentry->d_inode->i_mutex);
if (IS_DEADDIR(path->dentry->d_inode))
goto out_unlock;
err = security_sb_check_sb(mnt, &nd->path);
err = security_sb_check_sb(mnt, path);
if (err)
goto out_unlock;
err = -ENOENT;
if (IS_ROOT(nd->path.dentry) || !d_unhashed(nd->path.dentry))
err = attach_recursive_mnt(mnt, &nd->path, NULL);
if (IS_ROOT(path->dentry) || !d_unhashed(path->dentry))
err = attach_recursive_mnt(mnt, path, NULL);
out_unlock:
mutex_unlock(&nd->path.dentry->d_inode->i_mutex);
mutex_unlock(&path->dentry->d_inode->i_mutex);
if (!err)
security_sb_post_addmount(mnt, &nd->path);
security_sb_post_addmount(mnt, path);
return err;
}
@ -1294,7 +1294,7 @@ static noinline int do_loopback(struct nameidata *nd, char *old_name,
if (!mnt)
goto out;
err = graft_tree(mnt, nd);
err = graft_tree(mnt, &nd->path);
if (err) {
LIST_HEAD(umount_list);
spin_lock(&vfsmount_lock);
@ -1501,7 +1501,7 @@ int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd,
goto unlock;
newmnt->mnt_flags = mnt_flags;
if ((err = graft_tree(newmnt, nd)))
if ((err = graft_tree(newmnt, &nd->path)))
goto unlock;
if (fslist) /* add to the specified expiration list */
@ -1987,15 +1987,13 @@ asmlinkage long sys_pivot_root(const char __user * new_root,
const char __user * put_old)
{
struct vfsmount *tmp;
struct nameidata new_nd, old_nd, user_nd;
struct path parent_path, root_parent;
struct nameidata new_nd, old_nd;
struct path parent_path, root_parent, root;
int error;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
lock_kernel();
error = __user_walk(new_root, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
&new_nd);
if (error)
@ -2015,7 +2013,7 @@ asmlinkage long sys_pivot_root(const char __user * new_root,
}
read_lock(&current->fs->lock);
user_nd.path = current->fs->root;
root = current->fs->root;
path_get(&current->fs->root);
read_unlock(&current->fs->lock);
down_write(&namespace_sem);
@ -2023,9 +2021,9 @@ asmlinkage long sys_pivot_root(const char __user * new_root,
error = -EINVAL;
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))
IS_MNT_SHARED(root.mnt->mnt_parent))
goto out2;
if (!check_mnt(user_nd.path.mnt))
if (!check_mnt(root.mnt))
goto out2;
error = -ENOENT;
if (IS_DEADDIR(new_nd.path.dentry->d_inode))
@ -2035,13 +2033,13 @@ asmlinkage long sys_pivot_root(const char __user * new_root,
if (d_unhashed(old_nd.path.dentry) && !IS_ROOT(old_nd.path.dentry))
goto out2;
error = -EBUSY;
if (new_nd.path.mnt == user_nd.path.mnt ||
old_nd.path.mnt == user_nd.path.mnt)
if (new_nd.path.mnt == root.mnt ||
old_nd.path.mnt == root.mnt)
goto out2; /* loop, on the same file system */
error = -EINVAL;
if (user_nd.path.mnt->mnt_root != user_nd.path.dentry)
if (root.mnt->mnt_root != root.dentry)
goto out2; /* not a mountpoint */
if (user_nd.path.mnt->mnt_parent == user_nd.path.mnt)
if (root.mnt->mnt_parent == root.mnt)
goto out2; /* not attached */
if (new_nd.path.mnt->mnt_root != new_nd.path.dentry)
goto out2; /* not a mountpoint */
@ -2063,27 +2061,26 @@ asmlinkage long sys_pivot_root(const char __user * new_root,
} else if (!is_subdir(old_nd.path.dentry, new_nd.path.dentry))
goto out3;
detach_mnt(new_nd.path.mnt, &parent_path);
detach_mnt(user_nd.path.mnt, &root_parent);
detach_mnt(root.mnt, &root_parent);
/* mount old root on put_old */
attach_mnt(user_nd.path.mnt, &old_nd.path);
attach_mnt(root.mnt, &old_nd.path);
/* 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.path, &new_nd.path);
security_sb_post_pivotroot(&user_nd.path, &new_nd.path);
chroot_fs_refs(&root, &new_nd.path);
security_sb_post_pivotroot(&root, &new_nd.path);
error = 0;
path_put(&root_parent);
path_put(&parent_path);
out2:
mutex_unlock(&old_nd.path.dentry->d_inode->i_mutex);
up_write(&namespace_sem);
path_put(&user_nd.path);
path_put(&root);
path_put(&old_nd.path);
out1:
path_put(&new_nd.path);
out0:
unlock_kernel();
return error;
out3:
spin_unlock(&vfsmount_lock);