mirror of
https://github.com/torvalds/linux.git
synced 2024-12-05 10:32:35 +00:00
32a3d848eb
FWIW, there's a bit of abuse of struct kstat in overlayfs object creation paths - for one thing, it ends up with a very small subset of struct kstat (mode + rdev), for another it also needs link in case of symlinks and ends up passing it separately. IMO it would be better to introduce a separate object for that. In principle, we might even lift that thing into general API and switch ->mkdir()/->mknod()/->symlink() to identical calling conventions. Hell knows, perhaps ->create() as well... Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
1076 lines
24 KiB
C
1076 lines
24 KiB
C
/*
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*
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* Copyright (C) 2011 Novell Inc.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*/
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#include <linux/fs.h>
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#include <linux/namei.h>
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#include <linux/xattr.h>
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#include <linux/security.h>
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#include <linux/cred.h>
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#include <linux/module.h>
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#include <linux/posix_acl.h>
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#include <linux/posix_acl_xattr.h>
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#include <linux/atomic.h>
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#include <linux/ratelimit.h>
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#include "overlayfs.h"
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static unsigned short ovl_redirect_max = 256;
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module_param_named(redirect_max, ovl_redirect_max, ushort, 0644);
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MODULE_PARM_DESC(ovl_redirect_max,
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"Maximum length of absolute redirect xattr value");
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void ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
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{
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int err;
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dget(wdentry);
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if (d_is_dir(wdentry))
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err = ovl_do_rmdir(wdir, wdentry);
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else
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err = ovl_do_unlink(wdir, wdentry);
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dput(wdentry);
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if (err) {
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pr_err("overlayfs: cleanup of '%pd2' failed (%i)\n",
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wdentry, err);
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}
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}
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struct dentry *ovl_lookup_temp(struct dentry *workdir, struct dentry *dentry)
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{
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struct dentry *temp;
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char name[20];
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static atomic_t temp_id = ATOMIC_INIT(0);
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/* counter is allowed to wrap, since temp dentries are ephemeral */
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snprintf(name, sizeof(name), "#%x", atomic_inc_return(&temp_id));
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temp = lookup_one_len(name, workdir, strlen(name));
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if (!IS_ERR(temp) && temp->d_inode) {
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pr_err("overlayfs: workdir/%s already exists\n", name);
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dput(temp);
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temp = ERR_PTR(-EIO);
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}
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return temp;
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}
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/* caller holds i_mutex on workdir */
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static struct dentry *ovl_whiteout(struct dentry *workdir,
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struct dentry *dentry)
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{
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int err;
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struct dentry *whiteout;
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struct inode *wdir = workdir->d_inode;
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whiteout = ovl_lookup_temp(workdir, dentry);
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if (IS_ERR(whiteout))
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return whiteout;
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err = ovl_do_whiteout(wdir, whiteout);
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if (err) {
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dput(whiteout);
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whiteout = ERR_PTR(err);
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}
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return whiteout;
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}
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int ovl_create_real(struct inode *dir, struct dentry *newdentry,
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struct cattr *attr, struct dentry *hardlink, bool debug)
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{
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int err;
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if (newdentry->d_inode)
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return -ESTALE;
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if (hardlink) {
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err = ovl_do_link(hardlink, dir, newdentry, debug);
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} else {
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switch (attr->mode & S_IFMT) {
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case S_IFREG:
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err = ovl_do_create(dir, newdentry, attr->mode, debug);
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break;
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case S_IFDIR:
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err = ovl_do_mkdir(dir, newdentry, attr->mode, debug);
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break;
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case S_IFCHR:
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case S_IFBLK:
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case S_IFIFO:
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case S_IFSOCK:
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err = ovl_do_mknod(dir, newdentry,
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attr->mode, attr->rdev, debug);
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break;
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case S_IFLNK:
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err = ovl_do_symlink(dir, newdentry, attr->link, debug);
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break;
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default:
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err = -EPERM;
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}
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}
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if (!err && WARN_ON(!newdentry->d_inode)) {
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/*
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* Not quite sure if non-instantiated dentry is legal or not.
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* VFS doesn't seem to care so check and warn here.
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*/
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err = -ENOENT;
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}
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return err;
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}
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static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry)
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{
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int err;
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err = ovl_do_setxattr(upperdentry, OVL_XATTR_OPAQUE, "y", 1, 0);
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if (!err)
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ovl_dentry_set_opaque(dentry);
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return err;
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}
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static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry,
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struct kstat *stat)
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{
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int err;
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enum ovl_path_type type;
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struct path realpath;
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const struct cred *old_cred;
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type = ovl_path_real(dentry, &realpath);
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old_cred = ovl_override_creds(dentry->d_sb);
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err = vfs_getattr(&realpath, stat);
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revert_creds(old_cred);
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if (err)
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return err;
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stat->dev = dentry->d_sb->s_dev;
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stat->ino = dentry->d_inode->i_ino;
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/*
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* It's probably not worth it to count subdirs to get the
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* correct link count. nlink=1 seems to pacify 'find' and
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* other utilities.
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*/
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if (OVL_TYPE_MERGE(type))
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stat->nlink = 1;
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return 0;
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}
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/* Common operations required to be done after creation of file on upper */
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static void ovl_instantiate(struct dentry *dentry, struct inode *inode,
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struct dentry *newdentry, bool hardlink)
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{
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ovl_dentry_version_inc(dentry->d_parent);
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ovl_dentry_update(dentry, newdentry);
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if (!hardlink) {
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ovl_inode_update(inode, d_inode(newdentry));
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ovl_copyattr(newdentry->d_inode, inode);
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} else {
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WARN_ON(ovl_inode_real(inode, NULL) != d_inode(newdentry));
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inc_nlink(inode);
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}
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d_instantiate(dentry, inode);
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}
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static bool ovl_type_merge(struct dentry *dentry)
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{
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return OVL_TYPE_MERGE(ovl_path_type(dentry));
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}
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static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
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struct cattr *attr, struct dentry *hardlink)
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{
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struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
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struct inode *udir = upperdir->d_inode;
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struct dentry *newdentry;
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int err;
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if (!hardlink && !IS_POSIXACL(udir))
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attr->mode &= ~current_umask();
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inode_lock_nested(udir, I_MUTEX_PARENT);
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newdentry = lookup_one_len(dentry->d_name.name, upperdir,
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dentry->d_name.len);
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err = PTR_ERR(newdentry);
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if (IS_ERR(newdentry))
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goto out_unlock;
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err = ovl_create_real(udir, newdentry, attr, hardlink, false);
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if (err)
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goto out_dput;
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if (ovl_type_merge(dentry->d_parent)) {
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/* Setting opaque here is just an optimization, allow to fail */
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ovl_set_opaque(dentry, newdentry);
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}
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ovl_instantiate(dentry, inode, newdentry, !!hardlink);
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newdentry = NULL;
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out_dput:
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dput(newdentry);
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out_unlock:
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inode_unlock(udir);
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return err;
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}
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static int ovl_lock_rename_workdir(struct dentry *workdir,
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struct dentry *upperdir)
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{
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/* Workdir should not be the same as upperdir */
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if (workdir == upperdir)
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goto err;
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/* Workdir should not be subdir of upperdir and vice versa */
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if (lock_rename(workdir, upperdir) != NULL)
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goto err_unlock;
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return 0;
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err_unlock:
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unlock_rename(workdir, upperdir);
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err:
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pr_err("overlayfs: failed to lock workdir+upperdir\n");
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return -EIO;
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}
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static struct dentry *ovl_clear_empty(struct dentry *dentry,
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struct list_head *list)
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{
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struct dentry *workdir = ovl_workdir(dentry);
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struct inode *wdir = workdir->d_inode;
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struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
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struct inode *udir = upperdir->d_inode;
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struct path upperpath;
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struct dentry *upper;
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struct dentry *opaquedir;
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struct kstat stat;
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int err;
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if (WARN_ON(!workdir))
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return ERR_PTR(-EROFS);
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err = ovl_lock_rename_workdir(workdir, upperdir);
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if (err)
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goto out;
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ovl_path_upper(dentry, &upperpath);
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err = vfs_getattr(&upperpath, &stat);
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if (err)
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goto out_unlock;
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err = -ESTALE;
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if (!S_ISDIR(stat.mode))
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goto out_unlock;
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upper = upperpath.dentry;
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if (upper->d_parent->d_inode != udir)
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goto out_unlock;
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opaquedir = ovl_lookup_temp(workdir, dentry);
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err = PTR_ERR(opaquedir);
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if (IS_ERR(opaquedir))
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goto out_unlock;
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err = ovl_create_real(wdir, opaquedir,
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&(struct cattr){.mode = stat.mode}, NULL, true);
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if (err)
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goto out_dput;
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err = ovl_copy_xattr(upper, opaquedir);
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if (err)
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goto out_cleanup;
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err = ovl_set_opaque(dentry, opaquedir);
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if (err)
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goto out_cleanup;
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inode_lock(opaquedir->d_inode);
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err = ovl_set_attr(opaquedir, &stat);
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inode_unlock(opaquedir->d_inode);
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if (err)
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goto out_cleanup;
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err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE);
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if (err)
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goto out_cleanup;
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ovl_cleanup_whiteouts(upper, list);
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ovl_cleanup(wdir, upper);
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unlock_rename(workdir, upperdir);
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/* dentry's upper doesn't match now, get rid of it */
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d_drop(dentry);
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return opaquedir;
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out_cleanup:
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ovl_cleanup(wdir, opaquedir);
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out_dput:
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dput(opaquedir);
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out_unlock:
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unlock_rename(workdir, upperdir);
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out:
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return ERR_PTR(err);
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}
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static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry)
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{
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int err;
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struct dentry *ret = NULL;
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enum ovl_path_type type = ovl_path_type(dentry);
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LIST_HEAD(list);
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err = ovl_check_empty_dir(dentry, &list);
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if (err) {
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ret = ERR_PTR(err);
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goto out_free;
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}
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/*
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* When removing an empty opaque directory, then it makes no sense to
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* replace it with an exact replica of itself.
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*
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* If no upperdentry then skip clearing whiteouts.
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*
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* Can race with copy-up, since we don't hold the upperdir mutex.
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* Doesn't matter, since copy-up can't create a non-empty directory
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* from an empty one.
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*/
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if (OVL_TYPE_UPPER(type) && OVL_TYPE_MERGE(type))
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ret = ovl_clear_empty(dentry, &list);
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out_free:
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ovl_cache_free(&list);
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return ret;
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}
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static int ovl_set_upper_acl(struct dentry *upperdentry, const char *name,
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const struct posix_acl *acl)
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{
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void *buffer;
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size_t size;
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int err;
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if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !acl)
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return 0;
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size = posix_acl_to_xattr(NULL, acl, NULL, 0);
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buffer = kmalloc(size, GFP_KERNEL);
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if (!buffer)
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return -ENOMEM;
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size = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
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err = size;
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if (err < 0)
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goto out_free;
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err = vfs_setxattr(upperdentry, name, buffer, size, XATTR_CREATE);
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out_free:
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kfree(buffer);
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return err;
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}
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|
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static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
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struct cattr *cattr,
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struct dentry *hardlink)
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{
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struct dentry *workdir = ovl_workdir(dentry);
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struct inode *wdir = workdir->d_inode;
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struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
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struct inode *udir = upperdir->d_inode;
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struct dentry *upper;
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struct dentry *newdentry;
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int err;
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struct posix_acl *acl, *default_acl;
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if (WARN_ON(!workdir))
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return -EROFS;
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if (!hardlink) {
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err = posix_acl_create(dentry->d_parent->d_inode,
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&cattr->mode, &default_acl, &acl);
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if (err)
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return err;
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}
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err = ovl_lock_rename_workdir(workdir, upperdir);
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if (err)
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goto out;
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newdentry = ovl_lookup_temp(workdir, dentry);
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err = PTR_ERR(newdentry);
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if (IS_ERR(newdentry))
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goto out_unlock;
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upper = lookup_one_len(dentry->d_name.name, upperdir,
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dentry->d_name.len);
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err = PTR_ERR(upper);
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if (IS_ERR(upper))
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goto out_dput;
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err = ovl_create_real(wdir, newdentry, cattr, hardlink, true);
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if (err)
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goto out_dput2;
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|
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/*
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* mode could have been mutilated due to umask (e.g. sgid directory)
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*/
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if (!hardlink &&
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!S_ISLNK(cattr->mode) &&
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newdentry->d_inode->i_mode != cattr->mode) {
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struct iattr attr = {
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.ia_valid = ATTR_MODE,
|
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.ia_mode = cattr->mode,
|
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};
|
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inode_lock(newdentry->d_inode);
|
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err = notify_change(newdentry, &attr, NULL);
|
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inode_unlock(newdentry->d_inode);
|
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if (err)
|
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goto out_cleanup;
|
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}
|
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if (!hardlink) {
|
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err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_ACCESS,
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acl);
|
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if (err)
|
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goto out_cleanup;
|
|
|
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err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_DEFAULT,
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default_acl);
|
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if (err)
|
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goto out_cleanup;
|
|
}
|
|
|
|
if (!hardlink && S_ISDIR(cattr->mode)) {
|
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err = ovl_set_opaque(dentry, newdentry);
|
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if (err)
|
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goto out_cleanup;
|
|
|
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err = ovl_do_rename(wdir, newdentry, udir, upper,
|
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RENAME_EXCHANGE);
|
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if (err)
|
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goto out_cleanup;
|
|
|
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ovl_cleanup(wdir, upper);
|
|
} else {
|
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err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
|
|
if (err)
|
|
goto out_cleanup;
|
|
}
|
|
ovl_instantiate(dentry, inode, newdentry, !!hardlink);
|
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newdentry = NULL;
|
|
out_dput2:
|
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dput(upper);
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|
out_dput:
|
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dput(newdentry);
|
|
out_unlock:
|
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unlock_rename(workdir, upperdir);
|
|
out:
|
|
if (!hardlink) {
|
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posix_acl_release(acl);
|
|
posix_acl_release(default_acl);
|
|
}
|
|
return err;
|
|
|
|
out_cleanup:
|
|
ovl_cleanup(wdir, newdentry);
|
|
goto out_dput2;
|
|
}
|
|
|
|
static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
|
|
struct cattr *attr, struct dentry *hardlink)
|
|
{
|
|
int err;
|
|
const struct cred *old_cred;
|
|
struct cred *override_cred;
|
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|
|
err = ovl_copy_up(dentry->d_parent);
|
|
if (err)
|
|
return err;
|
|
|
|
old_cred = ovl_override_creds(dentry->d_sb);
|
|
err = -ENOMEM;
|
|
override_cred = prepare_creds();
|
|
if (override_cred) {
|
|
override_cred->fsuid = inode->i_uid;
|
|
override_cred->fsgid = inode->i_gid;
|
|
if (!hardlink) {
|
|
err = security_dentry_create_files_as(dentry,
|
|
attr->mode, &dentry->d_name, old_cred,
|
|
override_cred);
|
|
if (err) {
|
|
put_cred(override_cred);
|
|
goto out_revert_creds;
|
|
}
|
|
}
|
|
put_cred(override_creds(override_cred));
|
|
put_cred(override_cred);
|
|
|
|
if (!ovl_dentry_is_whiteout(dentry))
|
|
err = ovl_create_upper(dentry, inode, attr,
|
|
hardlink);
|
|
else
|
|
err = ovl_create_over_whiteout(dentry, inode, attr,
|
|
hardlink);
|
|
}
|
|
out_revert_creds:
|
|
revert_creds(old_cred);
|
|
if (!err) {
|
|
struct inode *realinode = d_inode(ovl_dentry_upper(dentry));
|
|
|
|
WARN_ON(inode->i_mode != realinode->i_mode);
|
|
WARN_ON(!uid_eq(inode->i_uid, realinode->i_uid));
|
|
WARN_ON(!gid_eq(inode->i_gid, realinode->i_gid));
|
|
}
|
|
return err;
|
|
}
|
|
|
|
static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
|
|
const char *link)
|
|
{
|
|
int err;
|
|
struct inode *inode;
|
|
struct cattr attr = {
|
|
.rdev = rdev,
|
|
.link = link,
|
|
};
|
|
|
|
err = ovl_want_write(dentry);
|
|
if (err)
|
|
goto out;
|
|
|
|
err = -ENOMEM;
|
|
inode = ovl_new_inode(dentry->d_sb, mode, rdev);
|
|
if (!inode)
|
|
goto out_drop_write;
|
|
|
|
inode_init_owner(inode, dentry->d_parent->d_inode, mode);
|
|
attr.mode = inode->i_mode;
|
|
|
|
err = ovl_create_or_link(dentry, inode, &attr, NULL);
|
|
if (err)
|
|
iput(inode);
|
|
|
|
out_drop_write:
|
|
ovl_drop_write(dentry);
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode,
|
|
bool excl)
|
|
{
|
|
return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL);
|
|
}
|
|
|
|
static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
|
|
{
|
|
return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL);
|
|
}
|
|
|
|
static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
|
|
dev_t rdev)
|
|
{
|
|
/* Don't allow creation of "whiteout" on overlay */
|
|
if (S_ISCHR(mode) && rdev == WHITEOUT_DEV)
|
|
return -EPERM;
|
|
|
|
return ovl_create_object(dentry, mode, rdev, NULL);
|
|
}
|
|
|
|
static int ovl_symlink(struct inode *dir, struct dentry *dentry,
|
|
const char *link)
|
|
{
|
|
return ovl_create_object(dentry, S_IFLNK, 0, link);
|
|
}
|
|
|
|
static int ovl_link(struct dentry *old, struct inode *newdir,
|
|
struct dentry *new)
|
|
{
|
|
int err;
|
|
struct inode *inode;
|
|
|
|
err = ovl_want_write(old);
|
|
if (err)
|
|
goto out;
|
|
|
|
err = ovl_copy_up(old);
|
|
if (err)
|
|
goto out_drop_write;
|
|
|
|
inode = d_inode(old);
|
|
ihold(inode);
|
|
|
|
err = ovl_create_or_link(new, inode, NULL, ovl_dentry_upper(old));
|
|
if (err)
|
|
iput(inode);
|
|
|
|
out_drop_write:
|
|
ovl_drop_write(old);
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir)
|
|
{
|
|
struct dentry *workdir = ovl_workdir(dentry);
|
|
struct inode *wdir = workdir->d_inode;
|
|
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
|
|
struct inode *udir = upperdir->d_inode;
|
|
struct dentry *whiteout;
|
|
struct dentry *upper;
|
|
struct dentry *opaquedir = NULL;
|
|
int err;
|
|
int flags = 0;
|
|
|
|
if (WARN_ON(!workdir))
|
|
return -EROFS;
|
|
|
|
if (is_dir) {
|
|
opaquedir = ovl_check_empty_and_clear(dentry);
|
|
err = PTR_ERR(opaquedir);
|
|
if (IS_ERR(opaquedir))
|
|
goto out;
|
|
}
|
|
|
|
err = ovl_lock_rename_workdir(workdir, upperdir);
|
|
if (err)
|
|
goto out_dput;
|
|
|
|
upper = lookup_one_len(dentry->d_name.name, upperdir,
|
|
dentry->d_name.len);
|
|
err = PTR_ERR(upper);
|
|
if (IS_ERR(upper))
|
|
goto out_unlock;
|
|
|
|
err = -ESTALE;
|
|
if ((opaquedir && upper != opaquedir) ||
|
|
(!opaquedir && ovl_dentry_upper(dentry) &&
|
|
upper != ovl_dentry_upper(dentry))) {
|
|
goto out_dput_upper;
|
|
}
|
|
|
|
whiteout = ovl_whiteout(workdir, dentry);
|
|
err = PTR_ERR(whiteout);
|
|
if (IS_ERR(whiteout))
|
|
goto out_dput_upper;
|
|
|
|
if (d_is_dir(upper))
|
|
flags = RENAME_EXCHANGE;
|
|
|
|
err = ovl_do_rename(wdir, whiteout, udir, upper, flags);
|
|
if (err)
|
|
goto kill_whiteout;
|
|
if (flags)
|
|
ovl_cleanup(wdir, upper);
|
|
|
|
ovl_dentry_version_inc(dentry->d_parent);
|
|
out_d_drop:
|
|
d_drop(dentry);
|
|
dput(whiteout);
|
|
out_dput_upper:
|
|
dput(upper);
|
|
out_unlock:
|
|
unlock_rename(workdir, upperdir);
|
|
out_dput:
|
|
dput(opaquedir);
|
|
out:
|
|
return err;
|
|
|
|
kill_whiteout:
|
|
ovl_cleanup(wdir, whiteout);
|
|
goto out_d_drop;
|
|
}
|
|
|
|
static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
|
|
{
|
|
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
|
|
struct inode *dir = upperdir->d_inode;
|
|
struct dentry *upper;
|
|
struct dentry *opaquedir = NULL;
|
|
int err;
|
|
|
|
/* Redirect dir can be !ovl_lower_positive && OVL_TYPE_MERGE */
|
|
if (is_dir && ovl_dentry_get_redirect(dentry)) {
|
|
opaquedir = ovl_check_empty_and_clear(dentry);
|
|
err = PTR_ERR(opaquedir);
|
|
if (IS_ERR(opaquedir))
|
|
goto out;
|
|
}
|
|
|
|
inode_lock_nested(dir, I_MUTEX_PARENT);
|
|
upper = lookup_one_len(dentry->d_name.name, upperdir,
|
|
dentry->d_name.len);
|
|
err = PTR_ERR(upper);
|
|
if (IS_ERR(upper))
|
|
goto out_unlock;
|
|
|
|
err = -ESTALE;
|
|
if ((opaquedir && upper != opaquedir) ||
|
|
(!opaquedir && upper != ovl_dentry_upper(dentry)))
|
|
goto out_dput_upper;
|
|
|
|
if (is_dir)
|
|
err = vfs_rmdir(dir, upper);
|
|
else
|
|
err = vfs_unlink(dir, upper, NULL);
|
|
ovl_dentry_version_inc(dentry->d_parent);
|
|
|
|
/*
|
|
* Keeping this dentry hashed would mean having to release
|
|
* upperpath/lowerpath, which could only be done if we are the
|
|
* sole user of this dentry. Too tricky... Just unhash for
|
|
* now.
|
|
*/
|
|
if (!err)
|
|
d_drop(dentry);
|
|
out_dput_upper:
|
|
dput(upper);
|
|
out_unlock:
|
|
inode_unlock(dir);
|
|
dput(opaquedir);
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static int ovl_do_remove(struct dentry *dentry, bool is_dir)
|
|
{
|
|
enum ovl_path_type type;
|
|
int err;
|
|
const struct cred *old_cred;
|
|
|
|
err = ovl_want_write(dentry);
|
|
if (err)
|
|
goto out;
|
|
|
|
err = ovl_copy_up(dentry->d_parent);
|
|
if (err)
|
|
goto out_drop_write;
|
|
|
|
type = ovl_path_type(dentry);
|
|
|
|
old_cred = ovl_override_creds(dentry->d_sb);
|
|
if (!ovl_lower_positive(dentry))
|
|
err = ovl_remove_upper(dentry, is_dir);
|
|
else
|
|
err = ovl_remove_and_whiteout(dentry, is_dir);
|
|
revert_creds(old_cred);
|
|
if (!err) {
|
|
if (is_dir)
|
|
clear_nlink(dentry->d_inode);
|
|
else
|
|
drop_nlink(dentry->d_inode);
|
|
}
|
|
out_drop_write:
|
|
ovl_drop_write(dentry);
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static int ovl_unlink(struct inode *dir, struct dentry *dentry)
|
|
{
|
|
return ovl_do_remove(dentry, false);
|
|
}
|
|
|
|
static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
|
|
{
|
|
return ovl_do_remove(dentry, true);
|
|
}
|
|
|
|
static bool ovl_type_merge_or_lower(struct dentry *dentry)
|
|
{
|
|
enum ovl_path_type type = ovl_path_type(dentry);
|
|
|
|
return OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type);
|
|
}
|
|
|
|
static bool ovl_can_move(struct dentry *dentry)
|
|
{
|
|
return ovl_redirect_dir(dentry->d_sb) ||
|
|
!d_is_dir(dentry) || !ovl_type_merge_or_lower(dentry);
|
|
}
|
|
|
|
static char *ovl_get_redirect(struct dentry *dentry, bool samedir)
|
|
{
|
|
char *buf, *ret;
|
|
struct dentry *d, *tmp;
|
|
int buflen = ovl_redirect_max + 1;
|
|
|
|
if (samedir) {
|
|
ret = kstrndup(dentry->d_name.name, dentry->d_name.len,
|
|
GFP_KERNEL);
|
|
goto out;
|
|
}
|
|
|
|
buf = ret = kmalloc(buflen, GFP_TEMPORARY);
|
|
if (!buf)
|
|
goto out;
|
|
|
|
buflen--;
|
|
buf[buflen] = '\0';
|
|
for (d = dget(dentry); !IS_ROOT(d);) {
|
|
const char *name;
|
|
int thislen;
|
|
|
|
spin_lock(&d->d_lock);
|
|
name = ovl_dentry_get_redirect(d);
|
|
if (name) {
|
|
thislen = strlen(name);
|
|
} else {
|
|
name = d->d_name.name;
|
|
thislen = d->d_name.len;
|
|
}
|
|
|
|
/* If path is too long, fall back to userspace move */
|
|
if (thislen + (name[0] != '/') > buflen) {
|
|
ret = ERR_PTR(-EXDEV);
|
|
spin_unlock(&d->d_lock);
|
|
goto out_put;
|
|
}
|
|
|
|
buflen -= thislen;
|
|
memcpy(&buf[buflen], name, thislen);
|
|
tmp = dget_dlock(d->d_parent);
|
|
spin_unlock(&d->d_lock);
|
|
|
|
dput(d);
|
|
d = tmp;
|
|
|
|
/* Absolute redirect: finished */
|
|
if (buf[buflen] == '/')
|
|
break;
|
|
buflen--;
|
|
buf[buflen] = '/';
|
|
}
|
|
ret = kstrdup(&buf[buflen], GFP_KERNEL);
|
|
out_put:
|
|
dput(d);
|
|
kfree(buf);
|
|
out:
|
|
return ret ? ret : ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
static int ovl_set_redirect(struct dentry *dentry, bool samedir)
|
|
{
|
|
int err;
|
|
const char *redirect = ovl_dentry_get_redirect(dentry);
|
|
|
|
if (redirect && (samedir || redirect[0] == '/'))
|
|
return 0;
|
|
|
|
redirect = ovl_get_redirect(dentry, samedir);
|
|
if (IS_ERR(redirect))
|
|
return PTR_ERR(redirect);
|
|
|
|
err = ovl_do_setxattr(ovl_dentry_upper(dentry), OVL_XATTR_REDIRECT,
|
|
redirect, strlen(redirect), 0);
|
|
if (!err) {
|
|
spin_lock(&dentry->d_lock);
|
|
ovl_dentry_set_redirect(dentry, redirect);
|
|
spin_unlock(&dentry->d_lock);
|
|
} else {
|
|
kfree(redirect);
|
|
if (err == -EOPNOTSUPP)
|
|
ovl_clear_redirect_dir(dentry->d_sb);
|
|
else
|
|
pr_warn_ratelimited("overlay: failed to set redirect (%i)\n", err);
|
|
/* Fall back to userspace copy-up */
|
|
err = -EXDEV;
|
|
}
|
|
return err;
|
|
}
|
|
|
|
static int ovl_rename(struct inode *olddir, struct dentry *old,
|
|
struct inode *newdir, struct dentry *new,
|
|
unsigned int flags)
|
|
{
|
|
int err;
|
|
struct dentry *old_upperdir;
|
|
struct dentry *new_upperdir;
|
|
struct dentry *olddentry;
|
|
struct dentry *newdentry;
|
|
struct dentry *trap;
|
|
bool old_opaque;
|
|
bool new_opaque;
|
|
bool cleanup_whiteout = false;
|
|
bool overwrite = !(flags & RENAME_EXCHANGE);
|
|
bool is_dir = d_is_dir(old);
|
|
bool new_is_dir = d_is_dir(new);
|
|
bool samedir = olddir == newdir;
|
|
struct dentry *opaquedir = NULL;
|
|
const struct cred *old_cred = NULL;
|
|
|
|
err = -EINVAL;
|
|
if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE))
|
|
goto out;
|
|
|
|
flags &= ~RENAME_NOREPLACE;
|
|
|
|
/* Don't copy up directory trees */
|
|
err = -EXDEV;
|
|
if (!ovl_can_move(old))
|
|
goto out;
|
|
if (!overwrite && !ovl_can_move(new))
|
|
goto out;
|
|
|
|
err = ovl_want_write(old);
|
|
if (err)
|
|
goto out;
|
|
|
|
err = ovl_copy_up(old);
|
|
if (err)
|
|
goto out_drop_write;
|
|
|
|
err = ovl_copy_up(new->d_parent);
|
|
if (err)
|
|
goto out_drop_write;
|
|
if (!overwrite) {
|
|
err = ovl_copy_up(new);
|
|
if (err)
|
|
goto out_drop_write;
|
|
}
|
|
|
|
old_cred = ovl_override_creds(old->d_sb);
|
|
|
|
if (overwrite && new_is_dir && ovl_type_merge_or_lower(new)) {
|
|
opaquedir = ovl_check_empty_and_clear(new);
|
|
err = PTR_ERR(opaquedir);
|
|
if (IS_ERR(opaquedir)) {
|
|
opaquedir = NULL;
|
|
goto out_revert_creds;
|
|
}
|
|
}
|
|
|
|
if (overwrite) {
|
|
if (ovl_lower_positive(old)) {
|
|
if (!ovl_dentry_is_whiteout(new)) {
|
|
/* Whiteout source */
|
|
flags |= RENAME_WHITEOUT;
|
|
} else {
|
|
/* Switch whiteouts */
|
|
flags |= RENAME_EXCHANGE;
|
|
}
|
|
} else if (is_dir && ovl_dentry_is_whiteout(new)) {
|
|
flags |= RENAME_EXCHANGE;
|
|
cleanup_whiteout = true;
|
|
}
|
|
}
|
|
|
|
old_upperdir = ovl_dentry_upper(old->d_parent);
|
|
new_upperdir = ovl_dentry_upper(new->d_parent);
|
|
|
|
trap = lock_rename(new_upperdir, old_upperdir);
|
|
|
|
olddentry = lookup_one_len(old->d_name.name, old_upperdir,
|
|
old->d_name.len);
|
|
err = PTR_ERR(olddentry);
|
|
if (IS_ERR(olddentry))
|
|
goto out_unlock;
|
|
|
|
err = -ESTALE;
|
|
if (olddentry != ovl_dentry_upper(old))
|
|
goto out_dput_old;
|
|
|
|
newdentry = lookup_one_len(new->d_name.name, new_upperdir,
|
|
new->d_name.len);
|
|
err = PTR_ERR(newdentry);
|
|
if (IS_ERR(newdentry))
|
|
goto out_dput_old;
|
|
|
|
old_opaque = ovl_dentry_is_opaque(old);
|
|
new_opaque = ovl_dentry_is_opaque(new);
|
|
|
|
err = -ESTALE;
|
|
if (ovl_dentry_upper(new)) {
|
|
if (opaquedir) {
|
|
if (newdentry != opaquedir)
|
|
goto out_dput;
|
|
} else {
|
|
if (newdentry != ovl_dentry_upper(new))
|
|
goto out_dput;
|
|
}
|
|
} else {
|
|
if (!d_is_negative(newdentry) &&
|
|
(!new_opaque || !ovl_is_whiteout(newdentry)))
|
|
goto out_dput;
|
|
}
|
|
|
|
if (olddentry == trap)
|
|
goto out_dput;
|
|
if (newdentry == trap)
|
|
goto out_dput;
|
|
|
|
if (WARN_ON(olddentry->d_inode == newdentry->d_inode))
|
|
goto out_dput;
|
|
|
|
err = 0;
|
|
if (is_dir) {
|
|
if (ovl_type_merge_or_lower(old))
|
|
err = ovl_set_redirect(old, samedir);
|
|
else if (!old_opaque && ovl_type_merge(new->d_parent))
|
|
err = ovl_set_opaque(old, olddentry);
|
|
if (err)
|
|
goto out_dput;
|
|
}
|
|
if (!overwrite && new_is_dir) {
|
|
if (ovl_type_merge_or_lower(new))
|
|
err = ovl_set_redirect(new, samedir);
|
|
else if (!new_opaque && ovl_type_merge(old->d_parent))
|
|
err = ovl_set_opaque(new, newdentry);
|
|
if (err)
|
|
goto out_dput;
|
|
}
|
|
|
|
err = ovl_do_rename(old_upperdir->d_inode, olddentry,
|
|
new_upperdir->d_inode, newdentry, flags);
|
|
if (err)
|
|
goto out_dput;
|
|
|
|
if (cleanup_whiteout)
|
|
ovl_cleanup(old_upperdir->d_inode, newdentry);
|
|
|
|
ovl_dentry_version_inc(old->d_parent);
|
|
ovl_dentry_version_inc(new->d_parent);
|
|
|
|
out_dput:
|
|
dput(newdentry);
|
|
out_dput_old:
|
|
dput(olddentry);
|
|
out_unlock:
|
|
unlock_rename(new_upperdir, old_upperdir);
|
|
out_revert_creds:
|
|
revert_creds(old_cred);
|
|
out_drop_write:
|
|
ovl_drop_write(old);
|
|
out:
|
|
dput(opaquedir);
|
|
return err;
|
|
}
|
|
|
|
const struct inode_operations ovl_dir_inode_operations = {
|
|
.lookup = ovl_lookup,
|
|
.mkdir = ovl_mkdir,
|
|
.symlink = ovl_symlink,
|
|
.unlink = ovl_unlink,
|
|
.rmdir = ovl_rmdir,
|
|
.rename = ovl_rename,
|
|
.link = ovl_link,
|
|
.setattr = ovl_setattr,
|
|
.create = ovl_create,
|
|
.mknod = ovl_mknod,
|
|
.permission = ovl_permission,
|
|
.getattr = ovl_dir_getattr,
|
|
.listxattr = ovl_listxattr,
|
|
.get_acl = ovl_get_acl,
|
|
.update_time = ovl_update_time,
|
|
};
|