fs: port ->setattr() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
Signed-off-by: Christian Brauner (Microsoft) <[e-mail]>

Documentation/filesystems/locking.rst

···
 	void (*truncate) (struct inode *);
 	int (*permission) (struct inode *, int, unsigned int);
 	struct posix_acl * (*get_inode_acl)(struct inode *, int, bool);
-	int (*setattr) (struct dentry *, struct iattr *);
+	int (*setattr) (struct mnt_idmap *, struct dentry *, struct iattr *);
 	int (*getattr) (const struct path *, struct kstat *, u32, unsigned int);
 	ssize_t (*listxattr) (struct dentry *, char *, size_t);
 	int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start, u64 len);

Documentation/filesystems/vfs.rst

···
 					 struct delayed_call *);
 		int (*permission) (struct user_namespace *, struct inode *, int);
 		struct posix_acl * (*get_inode_acl)(struct inode *, int, bool);
-		int (*setattr) (struct user_namespace *, struct dentry *, struct iattr *);
+		int (*setattr) (struct mnt_idmap *, struct dentry *, struct iattr *);
 		int (*getattr) (struct user_namespace *, const struct path *, struct kstat *, u32, unsigned int);
 		ssize_t (*listxattr) (struct dentry *, char *, size_t);
 		void (*update_time)(struct inode *, struct timespec *, int);

arch/powerpc/platforms/cell/spufs/inode.c

···
 }
 
 static int
-spufs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+spufs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	      struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
···
 	if ((attr->ia_valid & ATTR_SIZE) &&
 	    (attr->ia_size != inode->i_size))
 		return -EINVAL;
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 	return 0;
 }

fs/9p/acl.c

···
 			 * FIXME should we update ctime ?
 			 * What is the following setxattr update the mode ?
 			 */
-			v9fs_vfs_setattr_dotl(&init_user_ns, dentry, &iattr);
+			v9fs_vfs_setattr_dotl(&nop_mnt_idmap, dentry, &iattr);
 		}
 		break;
 	case ACL_TYPE_DEFAULT:

fs/9p/v9fs_vfs.h

···
 int v9fs_uflags2omode(int uflags, int extended);
 
 void v9fs_blank_wstat(struct p9_wstat *wstat);
-int v9fs_vfs_setattr_dotl(struct user_namespace *mnt_userns,
+int v9fs_vfs_setattr_dotl(struct mnt_idmap *idmap,
 			  struct dentry *dentry, struct iattr *iattr);
 int v9fs_file_fsync_dotl(struct file *filp, loff_t start, loff_t end,
 			 int datasync);

fs/9p/vfs_inode.c

···
 
 /**
  * v9fs_vfs_setattr - set file metadata
- * @mnt_userns: The user namespace of the mount
+ * @idmap: idmap of the mount
  * @dentry: file whose metadata to set
  * @iattr: metadata assignment structure
  *
  */
 
-static int v9fs_vfs_setattr(struct user_namespace *mnt_userns,
+static int v9fs_vfs_setattr(struct mnt_idmap *idmap,
 			    struct dentry *dentry, struct iattr *iattr)
 {
 	int retval, use_dentry = 0;
···
 	struct p9_wstat wstat;
 
 	p9_debug(P9_DEBUG_VFS, "\n");
-	retval = setattr_prepare(&init_user_ns, dentry, iattr);
+	retval = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
 	if (retval)
 		return retval;
 
···
 
 	v9fs_invalidate_inode_attr(inode);
 
-	setattr_copy(&init_user_ns, inode, iattr);
+	setattr_copy(&nop_mnt_idmap, inode, iattr);
 	mark_inode_dirty(inode);
 	return 0;
 }

fs/9p/vfs_inode_dotl.c

···
 
 /**
  * v9fs_vfs_setattr_dotl - set file metadata
- * @mnt_userns: The user namespace of the mount
+ * @idmap: idmap of the mount
  * @dentry: file whose metadata to set
  * @iattr: metadata assignment structure
  *
  */
 
-int v9fs_vfs_setattr_dotl(struct user_namespace *mnt_userns,
+int v9fs_vfs_setattr_dotl(struct mnt_idmap *idmap,
 			  struct dentry *dentry, struct iattr *iattr)
 {
 	int retval, use_dentry = 0;
···
 
 	p9_debug(P9_DEBUG_VFS, "\n");
 
-	retval = setattr_prepare(&init_user_ns, dentry, iattr);
+	retval = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
 	if (retval)
 		return retval;
 
···
 		truncate_setsize(inode, iattr->ia_size);
 
 	v9fs_invalidate_inode_attr(inode);
-	setattr_copy(&init_user_ns, inode, iattr);
+	setattr_copy(&nop_mnt_idmap, inode, iattr);
 	mark_inode_dirty(inode);
 	if (iattr->ia_valid & ATTR_MODE) {
 		/* We also want to update ACL when we update mode bits */

fs/adfs/adfs.h

···
 /* Inode stuff */
 struct inode *adfs_iget(struct super_block *sb, struct object_info *obj);
 int adfs_write_inode(struct inode *inode, struct writeback_control *wbc);
-int adfs_notify_change(struct user_namespace *mnt_userns, struct dentry *dentry,
+int adfs_notify_change(struct mnt_idmap *idmap, struct dentry *dentry,
 		       struct iattr *attr);
 
 /* map.c */

fs/adfs/inode.c

···
  * later.
  */
 int
-adfs_notify_change(struct user_namespace *mnt_userns, struct dentry *dentry,
+adfs_notify_change(struct mnt_idmap *idmap, struct dentry *dentry,
 		   struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
···
 	unsigned int ia_valid = attr->ia_valid;
 	int error;
 	
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 
 	/*
 	 * we can't change the UID or GID of any file -

fs/affs/affs.h

···
 /* inode.c */
 
 extern struct inode		*affs_new_inode(struct inode *dir);
-extern int			 affs_notify_change(struct user_namespace *mnt_userns,
+extern int			 affs_notify_change(struct mnt_idmap *idmap,
 					struct dentry *dentry, struct iattr *attr);
 extern void			 affs_evict_inode(struct inode *inode);
 extern struct inode		*affs_iget(struct super_block *sb,

fs/affs/inode.c

···
 }
 
 int
-affs_notify_change(struct user_namespace *mnt_userns, struct dentry *dentry,
+affs_notify_change(struct mnt_idmap *idmap, struct dentry *dentry,
 		   struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
···
 
 	pr_debug("notify_change(%lu,0x%x)\n", inode->i_ino, attr->ia_valid);
 
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (error)
 		goto out;
 
···
 		affs_truncate(inode);
 	}
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 
 	if (attr->ia_valid & ATTR_MODE)

fs/afs/inode.c

···
 /*
  * set the attributes of an inode
  */
-int afs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int afs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		struct iattr *attr)
 {
 	const unsigned int supported =

fs/afs/internal.h

···
 extern int afs_validate(struct afs_vnode *, struct key *);
 extern int afs_getattr(struct user_namespace *mnt_userns, const struct path *,
 		       struct kstat *, u32, unsigned int);
-extern int afs_setattr(struct user_namespace *mnt_userns, struct dentry *, struct iattr *);
+extern int afs_setattr(struct mnt_idmap *idmap, struct dentry *, struct iattr *);
 extern void afs_evict_inode(struct inode *);
 extern int afs_drop_inode(struct inode *);
 

fs/attr.c

···
 
 /**
  * setattr_prepare - check if attribute changes to a dentry are allowed
- * @mnt_userns:	user namespace of the mount the inode was found from
+ * @idmap:	idmap of the mount the inode was found from
  * @dentry:	dentry to check
  * @attr:	attributes to change
  *
···
  * SGID bit from mode if user is not allowed to set it. Also file capabilities
  * and IMA extended attributes are cleared if ATTR_KILL_PRIV is set.
  *
- * If the inode has been found through an idmapped mount the user namespace of
- * the vfsmount must be passed through @mnt_userns. This function will then
- * take care to map the inode according to @mnt_userns before checking
+ * If the inode has been found through an idmapped mount the idmap of
+ * the vfsmount must be passed through @idmap. This function will then
+ * take care to map the inode according to @idmap before checking
  * permissions. On non-idmapped mounts or if permission checking is to be
- * performed on the raw inode simply passs init_user_ns.
+ * performed on the raw inode simply passs @nop_mnt_idmap.
  *
  * Should be called as the first thing in ->setattr implementations,
  * possibly after taking additional locks.
  */
-int setattr_prepare(struct user_namespace *mnt_userns, struct dentry *dentry,
+int setattr_prepare(struct mnt_idmap *idmap, struct dentry *dentry,
 		    struct iattr *attr)
 {
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct inode *inode = d_inode(dentry);
 	unsigned int ia_valid = attr->ia_valid;
 
···
 
 /**
  * setattr_copy - copy simple metadata updates into the generic inode
- * @mnt_userns:	user namespace of the mount the inode was found from
+ * @idmap:	idmap of the mount the inode was found from
  * @inode:	the inode to be updated
  * @attr:	the new attributes
  *
···
  * Noticeably missing is inode size update, which is more complex
  * as it requires pagecache updates.
  *
- * If the inode has been found through an idmapped mount the user namespace of
- * the vfsmount must be passed through @mnt_userns. This function will then
- * take care to map the inode according to @mnt_userns before checking
+ * If the inode has been found through an idmapped mount the idmap of
+ * the vfsmount must be passed through @idmap. This function will then
+ * take care to map the inode according to @idmap before checking
  * permissions. On non-idmapped mounts or if permission checking is to be
- * performed on the raw inode simply passs init_user_ns.
+ * performed on the raw inode simply pass @nop_mnt_idmap.
  *
  * The inode is not marked as dirty after this operation. The rationale is
  * that for "simple" filesystems, the struct inode is the inode storage.
  * The caller is free to mark the inode dirty afterwards if needed.
  */
-void setattr_copy(struct user_namespace *mnt_userns, struct inode *inode,
+void setattr_copy(struct mnt_idmap *idmap, struct inode *inode,
 		  const struct iattr *attr)
 {
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	unsigned int ia_valid = attr->ia_valid;
 
 	i_uid_update(mnt_userns, attr, inode);
···
 	    !vfsgid_valid(i_gid_into_vfsgid(mnt_userns, inode)))
 		return -EOVERFLOW;
 
-	error = security_inode_setattr(mnt_userns, dentry, attr);
+	error = security_inode_setattr(idmap, dentry, attr);
 	if (error)
 		return error;
 	error = try_break_deleg(inode, delegated_inode);
···
 		return error;
 
 	if (inode->i_op->setattr)
-		error = inode->i_op->setattr(mnt_userns, dentry, attr);
+		error = inode->i_op->setattr(idmap, dentry, attr);
 	else
-		error = simple_setattr(mnt_userns, dentry, attr);
+		error = simple_setattr(idmap, dentry, attr);
 
 	if (!error) {
 		fsnotify_change(dentry, ia_valid);

fs/bad_inode.c

···
 	return -EIO;
 }
 
-static int bad_inode_setattr(struct user_namespace *mnt_userns,
+static int bad_inode_setattr(struct mnt_idmap *idmap,
 			     struct dentry *direntry, struct iattr *attrs)
 {
 	return -EIO;

fs/btrfs/inode.c

···
 	return ret;
 }
 
-static int btrfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+static int btrfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 			 struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
···
 	if (btrfs_root_readonly(root))
 		return -EROFS;
 
-	err = setattr_prepare(mnt_userns, dentry, attr);
+	err = setattr_prepare(idmap, dentry, attr);
 	if (err)
 		return err;
 
···
 	}
 
 	if (attr->ia_valid) {
-		setattr_copy(mnt_userns, inode, attr);
+		setattr_copy(idmap, inode, attr);
 		inode_inc_iversion(inode);
 		err = btrfs_dirty_inode(BTRFS_I(inode));
 
 		if (!err && attr->ia_valid & ATTR_MODE)
-			err = posix_acl_chmod(mnt_userns, dentry, inode->i_mode);
+			err = posix_acl_chmod(mnt_idmap_owner(idmap), dentry,
+					      inode->i_mode);
 	}
 
 	return err;

fs/ceph/inode.c

···
 /*
  * setattr
  */
-int ceph_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int ceph_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		 struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
···
 	if (ceph_inode_is_shutdown(inode))
 		return -ESTALE;
 
-	err = setattr_prepare(&init_user_ns, dentry, attr);
+	err = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (err != 0)
 		return err;
 

fs/ceph/super.h

···
 extern int ceph_permission(struct user_namespace *mnt_userns,
 			   struct inode *inode, int mask);
 extern int __ceph_setattr(struct inode *inode, struct iattr *attr);
-extern int ceph_setattr(struct user_namespace *mnt_userns,
+extern int ceph_setattr(struct mnt_idmap *idmap,
 			struct dentry *dentry, struct iattr *attr);
 extern int ceph_getattr(struct user_namespace *mnt_userns,
 			const struct path *path, struct kstat *stat,

fs/cifs/cifsfs.h

···
 extern int cifs_zap_mapping(struct inode *inode);
 extern int cifs_getattr(struct user_namespace *, const struct path *,
 			struct kstat *, u32, unsigned int);
-extern int cifs_setattr(struct user_namespace *, struct dentry *,
+extern int cifs_setattr(struct mnt_idmap *, struct dentry *,
 			struct iattr *);
 extern int cifs_fiemap(struct inode *, struct fiemap_extent_info *, u64 start,
 		       u64 len);

fs/cifs/inode.c

···
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_PERM)
 		attrs->ia_valid |= ATTR_FORCE;
 
-	rc = setattr_prepare(&init_user_ns, direntry, attrs);
+	rc = setattr_prepare(&nop_mnt_idmap, direntry, attrs);
 	if (rc < 0)
 		goto out;
 
···
 		fscache_resize_cookie(cifs_inode_cookie(inode), attrs->ia_size);
 	}
 
-	setattr_copy(&init_user_ns, inode, attrs);
+	setattr_copy(&nop_mnt_idmap, inode, attrs);
 	mark_inode_dirty(inode);
 
 	/* force revalidate when any of these times are set since some
···
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_PERM)
 		attrs->ia_valid |= ATTR_FORCE;
 
-	rc = setattr_prepare(&init_user_ns, direntry, attrs);
+	rc = setattr_prepare(&nop_mnt_idmap, direntry, attrs);
 	if (rc < 0)
 		goto cifs_setattr_exit;
 
···
 		fscache_resize_cookie(cifs_inode_cookie(inode), attrs->ia_size);
 	}
 
-	setattr_copy(&init_user_ns, inode, attrs);
+	setattr_copy(&nop_mnt_idmap, inode, attrs);
 	mark_inode_dirty(inode);
 
 cifs_setattr_exit:
···
 }
 
 int
-cifs_setattr(struct user_namespace *mnt_userns, struct dentry *direntry,
+cifs_setattr(struct mnt_idmap *idmap, struct dentry *direntry,
 	     struct iattr *attrs)
 {
 	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);

fs/coda/coda_linux.h

···
 int coda_revalidate_inode(struct inode *);
 int coda_getattr(struct user_namespace *, const struct path *, struct kstat *,
 		 u32, unsigned int);
-int coda_setattr(struct user_namespace *, struct dentry *, struct iattr *);
+int coda_setattr(struct mnt_idmap *, struct dentry *, struct iattr *);
 
 /* this file:  helpers */
 char *coda_f2s(struct CodaFid *f);

fs/coda/inode.c

···
 	return err;
 }
 
-int coda_setattr(struct user_namespace *mnt_userns, struct dentry *de,
+int coda_setattr(struct mnt_idmap *idmap, struct dentry *de,
 		 struct iattr *iattr)
 {
 	struct inode *inode = d_inode(de);

fs/configfs/configfs_internal.h

···
 
 extern const unsigned char * configfs_get_name(struct configfs_dirent *sd);
 extern void configfs_drop_dentry(struct configfs_dirent *sd, struct dentry *parent);
-extern int configfs_setattr(struct user_namespace *mnt_userns,
+extern int configfs_setattr(struct mnt_idmap *idmap,
 			    struct dentry *dentry, struct iattr *iattr);
 
 extern struct dentry *configfs_pin_fs(void);

fs/configfs/inode.c

···
 	.setattr	= configfs_setattr,
 };
 
-int configfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int configfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		     struct iattr *iattr)
 {
 	struct inode * inode = d_inode(dentry);
···
 	}
 	/* attributes were changed atleast once in past */
 
-	error = simple_setattr(mnt_userns, dentry, iattr);
+	error = simple_setattr(idmap, dentry, iattr);
 	if (error)
 		return error;
 

fs/debugfs/inode.c

···
  * so that we can use the file mode as part of a heuristic to determine whether
  * to lock down individual files.
  */
-static int debugfs_setattr(struct user_namespace *mnt_userns,
+static int debugfs_setattr(struct mnt_idmap *idmap,
 			   struct dentry *dentry, struct iattr *ia)
 {
 	int ret;
···
 		if (ret)
 			return ret;
 	}
-	return simple_setattr(&init_user_ns, dentry, ia);
+	return simple_setattr(&nop_mnt_idmap, dentry, ia);
 }
 
 static const struct inode_operations debugfs_file_inode_operations = {

fs/ecryptfs/inode.c

···
 
 /**
  * ecryptfs_setattr
- * @mnt_userns: user namespace of the target mount
+ * @idmap: idmap of the target mount
  * @dentry: dentry handle to the inode to modify
  * @ia: Structure with flags of what to change and values
  *
···
  * All other metadata changes will be passed right to the lower filesystem,
  * and we will just update our inode to look like the lower.
  */
-static int ecryptfs_setattr(struct user_namespace *mnt_userns,
+static int ecryptfs_setattr(struct mnt_idmap *idmap,
 			    struct dentry *dentry, struct iattr *ia)
 {
 	int rc = 0;
···
 	}
 	mutex_unlock(&crypt_stat->cs_mutex);
 
-	rc = setattr_prepare(&init_user_ns, dentry, ia);
+	rc = setattr_prepare(&nop_mnt_idmap, dentry, ia);
 	if (rc)
 		goto out;
 	if (ia->ia_valid & ATTR_SIZE) {

fs/exfat/exfat_fs.h

···
 extern const struct file_operations exfat_file_operations;
 int __exfat_truncate(struct inode *inode);
 void exfat_truncate(struct inode *inode);
-int exfat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int exfat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		  struct iattr *attr);
 int exfat_getattr(struct user_namespace *mnt_userns, const struct path *path,
 		  struct kstat *stat, unsigned int request_mask,

fs/exfat/file.c

···
 	return 0;
 }
 
-int exfat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int exfat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		  struct iattr *attr)
 {
 	struct exfat_sb_info *sbi = EXFAT_SB(dentry->d_sb);
···
 				ATTR_TIMES_SET);
 	}
 
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	attr->ia_valid = ia_valid;
 	if (error)
 		goto out;
···
 	if (attr->ia_valid & ATTR_SIZE)
 		inode->i_mtime = inode->i_ctime = current_time(inode);
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	exfat_truncate_atime(&inode->i_atime);
 
 	if (attr->ia_valid & ATTR_SIZE) {

fs/ext2/ext2.h

···
 extern int ext2_write_inode (struct inode *, struct writeback_control *);
 extern void ext2_evict_inode(struct inode *);
 extern int ext2_get_block(struct inode *, sector_t, struct buffer_head *, int);
-extern int ext2_setattr (struct user_namespace *, struct dentry *, struct iattr *);
+extern int ext2_setattr (struct mnt_idmap *, struct dentry *, struct iattr *);
 extern int ext2_getattr (struct user_namespace *, const struct path *,
 			 struct kstat *, u32, unsigned int);
 extern void ext2_set_inode_flags(struct inode *inode);

fs/ext2/inode.c

···
 	return 0;
 }
 
-int ext2_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int ext2_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		 struct iattr *iattr)
 {
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct inode *inode = d_inode(dentry);
 	int error;
 
-	error = setattr_prepare(&init_user_ns, dentry, iattr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
 	if (error)
 		return error;
 
···
 		if (error)
 			return error;
 	}
-	setattr_copy(&init_user_ns, inode, iattr);
+	setattr_copy(&nop_mnt_idmap, inode, iattr);
 	if (iattr->ia_valid & ATTR_MODE)
 		error = posix_acl_chmod(&init_user_ns, dentry, inode->i_mode);
 	mark_inode_dirty(inode);

fs/ext4/ext4.h

···
 	__ext4_iget((sb), (ino), (flags), __func__, __LINE__)
 
 extern int  ext4_write_inode(struct inode *, struct writeback_control *);
-extern int  ext4_setattr(struct user_namespace *, struct dentry *,
+extern int  ext4_setattr(struct mnt_idmap *, struct dentry *,
 			 struct iattr *);
 extern u32  ext4_dio_alignment(struct inode *inode);
 extern int  ext4_getattr(struct user_namespace *, const struct path *,

fs/ext4/inode.c

···
  *
  * Called with inode->i_rwsem down.
  */
-int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int ext4_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		 struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
···
 	int orphan = 0;
 	const unsigned int ia_valid = attr->ia_valid;
 	bool inc_ivers = true;
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 
 	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
 		return -EIO;
···
 				  ATTR_GID | ATTR_TIMES_SET))))
 		return -EPERM;
 
-	error = setattr_prepare(mnt_userns, dentry, attr);
+	error = setattr_prepare(idmap, dentry, attr);
 	if (error)
 		return error;
 
···
 	if (!error) {
 		if (inc_ivers)
 			inode_inc_iversion(inode);
-		setattr_copy(mnt_userns, inode, attr);
+		setattr_copy(idmap, inode, attr);
 		mark_inode_dirty(inode);
 	}
 

fs/f2fs/f2fs.h

···
 int f2fs_truncate(struct inode *inode);
 int f2fs_getattr(struct user_namespace *mnt_userns, const struct path *path,
 		 struct kstat *stat, u32 request_mask, unsigned int flags);
-int f2fs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		 struct iattr *attr);
 int f2fs_truncate_hole(struct inode *inode, pgoff_t pg_start, pgoff_t pg_end);
 void f2fs_truncate_data_blocks_range(struct dnode_of_data *dn, int count);

fs/f2fs/file.c

···
 }
 
 #ifdef CONFIG_F2FS_FS_POSIX_ACL
-static void __setattr_copy(struct user_namespace *mnt_userns,
+static void __setattr_copy(struct mnt_idmap *idmap,
 			   struct inode *inode, const struct iattr *attr)
 {
 	unsigned int ia_valid = attr->ia_valid;
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 
 	i_uid_update(mnt_userns, attr, inode);
 	i_gid_update(mnt_userns, attr, inode);
···
 #define __setattr_copy setattr_copy
 #endif
 
-int f2fs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		 struct iattr *attr)
 {
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct inode *inode = d_inode(dentry);
 	int err;
 
···
 		!f2fs_is_compress_backend_ready(inode))
 		return -EOPNOTSUPP;
 
-	err = setattr_prepare(mnt_userns, dentry, attr);
+	err = setattr_prepare(idmap, dentry, attr);
 	if (err)
 		return err;
 
···
 		spin_unlock(&F2FS_I(inode)->i_size_lock);
 	}
 
-	__setattr_copy(mnt_userns, inode, attr);
+	__setattr_copy(idmap, inode, attr);
 
 	if (attr->ia_valid & ATTR_MODE) {
 		err = posix_acl_chmod(mnt_userns, dentry, f2fs_get_inode_mode(inode));

fs/fat/fat.h

···
 			      unsigned long arg);
 extern const struct file_operations fat_file_operations;
 extern const struct inode_operations fat_file_inode_operations;
-extern int fat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+extern int fat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		       struct iattr *attr);
 extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
 extern int fat_getattr(struct user_namespace *mnt_userns,

fs/fat/file.c

···
 	 * out the RO attribute for checking by the security
 	 * module, just because it maps to a file mode.
 	 */
-	err = security_inode_setattr(file_mnt_user_ns(file),
+	err = security_inode_setattr(file_mnt_idmap(file),
 				     file->f_path.dentry, &ia);
 	if (err)
 		goto out_unlock_inode;
 
 	/* This MUST be done before doing anything irreversible... */
-	err = fat_setattr(file_mnt_user_ns(file), file->f_path.dentry, &ia);
+	err = fat_setattr(file_mnt_idmap(file), file->f_path.dentry, &ia);
 	if (err)
 		goto out_unlock_inode;
 
···
 /* valid file mode bits */
 #define FAT_VALID_MODE	(S_IFREG | S_IFDIR | S_IRWXUGO)
 
-int fat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int fat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		struct iattr *attr)
 {
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
 	struct inode *inode = d_inode(dentry);
 	unsigned int ia_valid;
···
 			attr->ia_valid &= ~TIMES_SET_FLAGS;
 	}
 
-	error = setattr_prepare(mnt_userns, dentry, attr);
+	error = setattr_prepare(idmap, dentry, attr);
 	attr->ia_valid = ia_valid;
 	if (error) {
 		if (sbi->options.quiet)
···
 		fat_truncate_time(inode, &attr->ia_mtime, S_MTIME);
 	attr->ia_valid &= ~(ATTR_ATIME|ATTR_CTIME|ATTR_MTIME);
 
-	setattr_copy(mnt_userns, inode, attr);
+	setattr_copy(idmap, inode, attr);
 	mark_inode_dirty(inode);
 out:
 	return error;

fs/fuse/dir.c

···
 	if (!fc->default_permissions)
 		attr->ia_valid |= ATTR_FORCE;
 
-	err = setattr_prepare(&init_user_ns, dentry, attr);
+	err = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (err)
 		return err;
 
···
 	return err;
 }
 
-static int fuse_setattr(struct user_namespace *mnt_userns, struct dentry *entry,
+static int fuse_setattr(struct mnt_idmap *idmap, struct dentry *entry,
 			struct iattr *attr)
 {
 	struct inode *inode = d_inode(entry);

fs/gfs2/inode.c

···
 
 static int __gfs2_setattr_simple(struct inode *inode, struct iattr *attr)
 {
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 	return 0;
 }
···
 
 /**
  * gfs2_setattr - Change attributes on an inode
- * @mnt_userns: User namespace of the mount the inode was found from
+ * @idmap: idmap of the mount the inode was found from
  * @dentry: The dentry which is changing
  * @attr: The structure describing the change
  *
···
  * Returns: errno
  */
 
-static int gfs2_setattr(struct user_namespace *mnt_userns,
+static int gfs2_setattr(struct mnt_idmap *idmap,
 			struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
···
 	if (error)
 		goto error;
 
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (error)
 		goto error;
 

fs/hfs/hfs_fs.h

···
 extern struct inode *hfs_new_inode(struct inode *, const struct qstr *, umode_t);
 extern void hfs_inode_write_fork(struct inode *, struct hfs_extent *, __be32 *, __be32 *);
 extern int hfs_write_inode(struct inode *, struct writeback_control *);
-extern int hfs_inode_setattr(struct user_namespace *, struct dentry *,
+extern int hfs_inode_setattr(struct mnt_idmap *, struct dentry *,
 			     struct iattr *);
 extern void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext,
 			__be32 log_size, __be32 phys_size, u32 clump_size);

fs/hfs/inode.c

···
  *     correspond to the same HFS file.
  */
 
-int hfs_inode_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int hfs_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		      struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
 	struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
 	int error;
 
-	error = setattr_prepare(&init_user_ns, dentry,
+	error = setattr_prepare(&nop_mnt_idmap, dentry,
 				attr); /* basic permission checks */
 	if (error)
 		return error;
···
 						  current_time(inode);
 	}
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 	return 0;
 }

fs/hfsplus/inode.c

···
 	return 0;
 }
 
-static int hfsplus_setattr(struct user_namespace *mnt_userns,
+static int hfsplus_setattr(struct mnt_idmap *idmap,
 			   struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
 	int error;
 
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (error)
 		return error;
 
···
 		inode->i_mtime = inode->i_ctime = current_time(inode);
 	}
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 
 	return 0;

fs/hostfs/hostfs_kern.c

···
 	return err;
 }
 
-static int hostfs_setattr(struct user_namespace *mnt_userns,
+static int hostfs_setattr(struct mnt_idmap *idmap,
 			  struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
···
 
 	int fd = HOSTFS_I(inode)->fd;
 
-	err = setattr_prepare(&init_user_ns, dentry, attr);
+	err = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (err)
 		return err;
 
···
 	    attr->ia_size != i_size_read(inode))
 		truncate_setsize(inode, attr->ia_size);
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 	return 0;
 }

fs/hpfs/hpfs_fn.h

···
 void hpfs_read_inode(struct inode *);
 void hpfs_write_inode(struct inode *);
 void hpfs_write_inode_nolock(struct inode *);
-int hpfs_setattr(struct user_namespace *, struct dentry *, struct iattr *);
+int hpfs_setattr(struct mnt_idmap *, struct dentry *, struct iattr *);
 void hpfs_write_if_changed(struct inode *);
 void hpfs_evict_inode(struct inode *);
 

fs/hpfs/inode.c

···
 	brelse(bh);
 }
 
-int hpfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int hpfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		 struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
···
 	if ((attr->ia_valid & ATTR_SIZE) && attr->ia_size > inode->i_size)
 		goto out_unlock;
 
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (error)
 		goto out_unlock;
 
···
 		hpfs_truncate(inode);
 	}
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 
 	hpfs_write_inode(inode);
 

fs/hugetlbfs/inode.c

···
 	return error;
 }
 
-static int hugetlbfs_setattr(struct user_namespace *mnt_userns,
+static int hugetlbfs_setattr(struct mnt_idmap *idmap,
 			     struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
···
 	unsigned int ia_valid = attr->ia_valid;
 	struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (error)
 		return error;
 
···
 		hugetlb_vmtruncate(inode, newsize);
 	}
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 	return 0;
 }

fs/jffs2/fs.c

···
 	return 0;
 }
 
-int jffs2_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int jffs2_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		  struct iattr *iattr)
 {
 	struct inode *inode = d_inode(dentry);
 	int rc;
 
-	rc = setattr_prepare(&init_user_ns, dentry, iattr);
+	rc = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
 	if (rc)
 		return rc;
 

fs/jffs2/os-linux.h

···
 extern const struct inode_operations jffs2_symlink_inode_operations;
 
 /* fs.c */
-int jffs2_setattr (struct user_namespace *, struct dentry *, struct iattr *);
+int jffs2_setattr (struct mnt_idmap *, struct dentry *, struct iattr *);
 int jffs2_do_setattr (struct inode *, struct iattr *);
 struct inode *jffs2_iget(struct super_block *, unsigned long);
 void jffs2_evict_inode (struct inode *);

fs/jfs/file.c

···
 	return 0;
 }
 
-int jfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int jfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		struct iattr *iattr)
 {
 	struct inode *inode = d_inode(dentry);
 	int rc;
 
-	rc = setattr_prepare(&init_user_ns, dentry, iattr);
+	rc = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
 	if (rc)
 		return rc;
 
-	if (is_quota_modification(mnt_userns, inode, iattr)) {
+	if (is_quota_modification(&init_user_ns, inode, iattr)) {
 		rc = dquot_initialize(inode);
 		if (rc)
 			return rc;
 	}
 	if ((iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)) ||
 	    (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid))) {
-		rc = dquot_transfer(mnt_userns, inode, iattr);
+		rc = dquot_transfer(&init_user_ns, inode, iattr);
 		if (rc)
 			return rc;
 	}
···
 		jfs_truncate(inode);
 	}
 
-	setattr_copy(&init_user_ns, inode, iattr);
+	setattr_copy(&nop_mnt_idmap, inode, iattr);
 	mark_inode_dirty(inode);
 
 	if (iattr->ia_valid & ATTR_MODE)

fs/jfs/jfs_inode.h

···
 	int fh_len, int fh_type);
 extern void jfs_set_inode_flags(struct inode *);
 extern int jfs_get_block(struct inode *, sector_t, struct buffer_head *, int);
-extern int jfs_setattr(struct user_namespace *, struct dentry *, struct iattr *);
+extern int jfs_setattr(struct mnt_idmap *, struct dentry *, struct iattr *);
 
 extern const struct address_space_operations jfs_aops;
 extern const struct inode_operations jfs_dir_inode_operations;

fs/kernfs/inode.c

···
 	return ret;
 }
 
-int kernfs_iop_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int kernfs_iop_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		       struct iattr *iattr)
 {
 	struct inode *inode = d_inode(dentry);
···
 
 	root = kernfs_root(kn);
 	down_write(&root->kernfs_rwsem);
-	error = setattr_prepare(&init_user_ns, dentry, iattr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
 	if (error)
 		goto out;
 
···
 		goto out;
 
 	/* this ignores size changes */
-	setattr_copy(&init_user_ns, inode, iattr);
+	setattr_copy(&nop_mnt_idmap, inode, iattr);
 
 out:
 	up_write(&root->kernfs_rwsem);

fs/kernfs/kernfs-internal.h

···
 void kernfs_evict_inode(struct inode *inode);
 int kernfs_iop_permission(struct user_namespace *mnt_userns,
 			  struct inode *inode, int mask);
-int kernfs_iop_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int kernfs_iop_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		       struct iattr *iattr);
 int kernfs_iop_getattr(struct user_namespace *mnt_userns,
 		       const struct path *path, struct kstat *stat,

fs/libfs.c

···
 
 /**
  * simple_setattr - setattr for simple filesystem
- * @mnt_userns: user namespace of the target mount
+ * @idmap: idmap of the target mount
  * @dentry: dentry
  * @iattr: iattr structure
  *
···
  * on simple regular filesystems.  Anything that needs to change on-disk
  * or wire state on size changes needs its own setattr method.
  */
-int simple_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int simple_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		   struct iattr *iattr)
 {
 	struct inode *inode = d_inode(dentry);
 	int error;
 
-	error = setattr_prepare(mnt_userns, dentry, iattr);
+	error = setattr_prepare(idmap, dentry, iattr);
 	if (error)
 		return error;
 
 	if (iattr->ia_valid & ATTR_SIZE)
 		truncate_setsize(inode, iattr->ia_size);
-	setattr_copy(mnt_userns, inode, iattr);
+	setattr_copy(idmap, inode, iattr);
 	mark_inode_dirty(inode);
 	return 0;
 }
···
 	return 0;
 }
 
-static int empty_dir_setattr(struct user_namespace *mnt_userns,
+static int empty_dir_setattr(struct mnt_idmap *idmap,
 			     struct dentry *dentry, struct iattr *attr)
 {
 	return -EPERM;

fs/minix/file.c

···
 	.splice_read	= generic_file_splice_read,
 };
 
-static int minix_setattr(struct user_namespace *mnt_userns,
+static int minix_setattr(struct mnt_idmap *idmap,
 			 struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
 	int error;
 
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (error)
 		return error;
 
···
 		minix_truncate(inode);
 	}
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 	return 0;
 }

fs/nfs/inode.c

···
 #define NFS_VALID_ATTRS (ATTR_MODE|ATTR_UID|ATTR_GID|ATTR_SIZE|ATTR_ATIME|ATTR_ATIME_SET|ATTR_MTIME|ATTR_MTIME_SET|ATTR_FILE|ATTR_OPEN)
 
 int
-nfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+nfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	    struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);

fs/nfs/namespace.c

···
 }
 
 static int
-nfs_namespace_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+nfs_namespace_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		      struct iattr *attr)
 {
 	if (NFS_FH(d_inode(dentry))->size != 0)
-		return nfs_setattr(mnt_userns, dentry, attr);
+		return nfs_setattr(idmap, dentry, attr);
 	return -EACCES;
 }
 

fs/nfsd/nfsproc.c

···
 		if (delta < 0)
 			delta = -delta;
 		if (delta < MAX_TOUCH_TIME_ERROR &&
-		    setattr_prepare(&init_user_ns, fhp->fh_dentry, iap) != 0) {
+		    setattr_prepare(&nop_mnt_idmap, fhp->fh_dentry, iap) != 0) {
 			/*
 			 * Turn off ATTR_[AM]TIME_SET but leave ATTR_[AM]TIME.
 			 * This will cause notify_change to set these times

fs/nilfs2/inode.c

···
 	 */
 }
 
-int nilfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int nilfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		  struct iattr *iattr)
 {
 	struct nilfs_transaction_info ti;
···
 	struct super_block *sb = inode->i_sb;
 	int err;
 
-	err = setattr_prepare(&init_user_ns, dentry, iattr);
+	err = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
 	if (err)
 		return err;
 
···
 		nilfs_truncate(inode);
 	}
 
-	setattr_copy(&init_user_ns, inode, iattr);
+	setattr_copy(&nop_mnt_idmap, inode, iattr);
 	mark_inode_dirty(inode);
 
 	if (iattr->ia_valid & ATTR_MODE) {

fs/nilfs2/nilfs.h

···
 extern void nilfs_update_inode(struct inode *, struct buffer_head *, int);
 extern void nilfs_truncate(struct inode *);
 extern void nilfs_evict_inode(struct inode *);
-extern int nilfs_setattr(struct user_namespace *, struct dentry *,
+extern int nilfs_setattr(struct mnt_idmap *, struct dentry *,
 			 struct iattr *);
 extern void nilfs_write_failed(struct address_space *mapping, loff_t to);
 int nilfs_permission(struct user_namespace *mnt_userns, struct inode *inode,

fs/ntfs/inode.c

···
 
 /**
  * ntfs_setattr - called from notify_change() when an attribute is being changed
- * @mnt_userns:	user namespace of the mount the inode was found from
+ * @idmap:	idmap of the mount the inode was found from
  * @dentry:	dentry whose attributes to change
  * @attr:	structure describing the attributes and the changes
  *
···
  *
  * Called with ->i_mutex held.
  */
-int ntfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int ntfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		 struct iattr *attr)
 {
 	struct inode *vi = d_inode(dentry);
 	int err;
 	unsigned int ia_valid = attr->ia_valid;
 
-	err = setattr_prepare(&init_user_ns, dentry, attr);
+	err = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (err)
 		goto out;
 	/* We do not support NTFS ACLs yet. */

fs/ntfs/inode.h

···
 extern int ntfs_truncate(struct inode *vi);
 extern void ntfs_truncate_vfs(struct inode *vi);
 
-extern int ntfs_setattr(struct user_namespace *mnt_userns,
+extern int ntfs_setattr(struct mnt_idmap *idmap,
 			struct dentry *dentry, struct iattr *attr);
 
 extern int __ntfs_write_inode(struct inode *vi, int sync);

fs/ntfs3/file.c

···
 /*
  * ntfs3_setattr - inode_operations::setattr
  */
-int ntfs3_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int ntfs3_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		  struct iattr *attr)
 {
 	struct super_block *sb = dentry->d_sb;
···
 		ia_valid = attr->ia_valid;
 	}
 
-	err = setattr_prepare(mnt_userns, dentry, attr);
+	err = setattr_prepare(idmap, dentry, attr);
 	if (err)
 		goto out;
 
···
 		inode->i_size = newsize;
 	}
 
-	setattr_copy(mnt_userns, inode, attr);
+	setattr_copy(idmap, inode, attr);
 
 	if (mode != inode->i_mode) {
-		err = ntfs_acl_chmod(mnt_userns, dentry);
+		err = ntfs_acl_chmod(mnt_idmap_owner(idmap), dentry);
 		if (err)
 			goto out;
 

fs/ntfs3/ntfs_fs.h

···
 /* Globals from file.c */
 int ntfs_getattr(struct user_namespace *mnt_userns, const struct path *path,
 		 struct kstat *stat, u32 request_mask, u32 flags);
-int ntfs3_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int ntfs3_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		  struct iattr *attr);
+void ntfs_sparse_cluster(struct inode *inode, struct page *page0, CLST vcn,
+			 CLST len);
 int ntfs_file_open(struct inode *inode, struct file *file);
 int ntfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 		__u64 start, __u64 len);

fs/ocfs2/dlmfs/dlmfs.c

···
  * We do ->setattr() just to override size changes.  Our size is the size
  * of the LVB and nothing else.
  */
-static int dlmfs_file_setattr(struct user_namespace *mnt_userns,
+static int dlmfs_file_setattr(struct mnt_idmap *idmap,
 			      struct dentry *dentry, struct iattr *attr)
 {
 	int error;
 	struct inode *inode = d_inode(dentry);
 
 	attr->ia_valid &= ~ATTR_SIZE;
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (error)
 		return error;
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 	return 0;
 }

fs/ocfs2/file.c

···
 	return ret;
 }
 
-int ocfs2_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int ocfs2_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		  struct iattr *attr)
 {
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	int status = 0, size_change;
 	int inode_locked = 0;
 	struct inode *inode = d_inode(dentry);
···
 	if (!(attr->ia_valid & OCFS2_VALID_ATTRS))
 		return 0;
 
-	status = setattr_prepare(&init_user_ns, dentry, attr);
+	status = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (status)
 		return status;
 
···
 		}
 	}
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 
 	status = ocfs2_mark_inode_dirty(handle, inode, bh);

fs/ocfs2/file.h

···
 			  u64 new_i_size, u64 zero_to);
 int ocfs2_zero_extend(struct inode *inode, struct buffer_head *di_bh,
 		      loff_t zero_to);
-int ocfs2_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int ocfs2_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		  struct iattr *attr);
 int ocfs2_getattr(struct user_namespace *mnt_userns, const struct path *path,
 		  struct kstat *stat, u32 request_mask, unsigned int flags);

fs/omfs/file.c

···
 	.splice_read = generic_file_splice_read,
 };
 
-static int omfs_setattr(struct user_namespace *mnt_userns,
+static int omfs_setattr(struct mnt_idmap *idmap,
 			struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
 	int error;
 
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (error)
 		return error;
 
···
 		omfs_truncate(inode);
 	}
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 	return 0;
 }

fs/orangefs/inode.c

···
 		ORANGEFS_I(inode)->attr_uid = current_fsuid();
 		ORANGEFS_I(inode)->attr_gid = current_fsgid();
 	}
-	setattr_copy(&init_user_ns, inode, iattr);
+	setattr_copy(&nop_mnt_idmap, inode, iattr);
 	spin_unlock(&inode->i_lock);
 	mark_inode_dirty(inode);
 
···
 /*
  * Change attributes of an object referenced by dentry.
  */
-int orangefs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int orangefs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		     struct iattr *iattr)
 {
 	int ret;
 	gossip_debug(GOSSIP_INODE_DEBUG, "__orangefs_setattr: called on %pd\n",
 	    dentry);
-	ret = setattr_prepare(&init_user_ns, dentry, iattr);
+	ret = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
 	if (ret)
 	        goto out;
 	ret = __orangefs_setattr_mode(dentry, iattr);

fs/orangefs/orangefs-kernel.h

···
 
 int __orangefs_setattr(struct inode *, struct iattr *);
 int __orangefs_setattr_mode(struct dentry *dentry, struct iattr *iattr);
-int orangefs_setattr(struct user_namespace *, struct dentry *, struct iattr *);
+int orangefs_setattr(struct mnt_idmap *, struct dentry *, struct iattr *);
 
 int orangefs_getattr(struct user_namespace *mnt_userns, const struct path *path,
 		     struct kstat *stat, u32 request_mask, unsigned int flags);

fs/overlayfs/inode.c

···
 #include "overlayfs.h"
 
 
-int ovl_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		struct iattr *attr)
 {
 	int err;
···
 	struct dentry *upperdentry;
 	const struct cred *old_cred;
 
-	err = setattr_prepare(&init_user_ns, dentry, attr);
+	err = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (err)
 		return err;
 
···
 	    !capable_wrt_inode_uidgid(&init_user_ns, inode, CAP_FSETID)) {
 		struct iattr iattr = { .ia_valid = ATTR_KILL_SGID };
 
-		err = ovl_setattr(&init_user_ns, dentry, &iattr);
+		err = ovl_setattr(&nop_mnt_idmap, dentry, &iattr);
 		if (err)
 			return err;
 	}

fs/overlayfs/overlayfs.h

···
 unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry,
 			   struct dentry *upperdentry,
 			   unsigned int fallback);
-int ovl_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		struct iattr *attr);
 int ovl_getattr(struct user_namespace *mnt_userns, const struct path *path,
 		struct kstat *stat, u32 request_mask, unsigned int flags);

fs/proc/base.c

···
 	return allowed;
 }
 
-int proc_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int proc_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		 struct iattr *attr)
 {
 	int error;
···
 	if (attr->ia_valid & ATTR_MODE)
 		return -EPERM;
 
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (error)
 		return error;
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 	return 0;
 }

fs/proc/generic.c

···
 	return true;
 }
 
-static int proc_notify_change(struct user_namespace *mnt_userns,
+static int proc_notify_change(struct mnt_idmap *idmap,
 			      struct dentry *dentry, struct iattr *iattr)
 {
 	struct inode *inode = d_inode(dentry);
 	struct proc_dir_entry *de = PDE(inode);
 	int error;
 
-	error = setattr_prepare(&init_user_ns, dentry, iattr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
 	if (error)
 		return error;
 
-	setattr_copy(&init_user_ns, inode, iattr);
+	setattr_copy(&nop_mnt_idmap, inode, iattr);
 	mark_inode_dirty(inode);
 
 	proc_set_user(de, inode->i_uid, inode->i_gid);

fs/proc/internal.h

···
 extern const struct dentry_operations pid_dentry_operations;
 extern int pid_getattr(struct user_namespace *, const struct path *,
 		       struct kstat *, u32, unsigned int);
-extern int proc_setattr(struct user_namespace *, struct dentry *,
+extern int proc_setattr(struct mnt_idmap *, struct dentry *,
 			struct iattr *);
 extern void proc_pid_evict_inode(struct proc_inode *);
 extern struct inode *proc_pid_make_inode(struct super_block *, struct task_struct *, umode_t);

fs/proc/proc_sysctl.c

···
 	return error;
 }
 
-static int proc_sys_setattr(struct user_namespace *mnt_userns,
+static int proc_sys_setattr(struct mnt_idmap *idmap,
 			    struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
···
 	if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))
 		return -EPERM;
 
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (error)
 		return error;
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 	return 0;
 }

fs/ramfs/file-nommu.c

···
 #include <linux/uaccess.h>
 #include "internal.h"
 
-static int ramfs_nommu_setattr(struct user_namespace *, struct dentry *, struct iattr *);
+static int ramfs_nommu_setattr(struct mnt_idmap *, struct dentry *, struct iattr *);
 static unsigned long ramfs_nommu_get_unmapped_area(struct file *file,
 						   unsigned long addr,
 						   unsigned long len,
···
  * handle a change of attributes
  * - we're specifically interested in a change of size
  */
-static int ramfs_nommu_setattr(struct user_namespace *mnt_userns,
+static int ramfs_nommu_setattr(struct mnt_idmap *idmap,
 			       struct dentry *dentry, struct iattr *ia)
 {
 	struct inode *inode = d_inode(dentry);
···
 	int ret = 0;
 
 	/* POSIX UID/GID verification for setting inode attributes */
-	ret = setattr_prepare(&init_user_ns, dentry, ia);
+	ret = setattr_prepare(&nop_mnt_idmap, dentry, ia);
 	if (ret)
 		return ret;
 
···
 		}
 	}
 
-	setattr_copy(&init_user_ns, inode, ia);
+	setattr_copy(&nop_mnt_idmap, inode, ia);
  out:
 	ia->ia_valid = old_ia_valid;
 	return ret;

fs/reiserfs/inode.c

···
 	return ret;
 }
 
-int reiserfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int reiserfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		     struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
 	unsigned int ia_valid;
 	int error;
 
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (error)
 		return error;
 
 	/* must be turned off for recursive notify_change calls */
 	ia_valid = attr->ia_valid &= ~(ATTR_KILL_SUID|ATTR_KILL_SGID);
 
-	if (is_quota_modification(mnt_userns, inode, attr)) {
+	if (is_quota_modification(&init_user_ns, inode, attr)) {
 		error = dquot_initialize(inode);
 		if (error)
 			return error;
···
 		reiserfs_write_unlock(inode->i_sb);
 		if (error)
 			goto out;
-		error = dquot_transfer(mnt_userns, inode, attr);
+		error = dquot_transfer(&init_user_ns, inode, attr);
 		reiserfs_write_lock(inode->i_sb);
 		if (error) {
 			journal_end(&th);
···
 	}
 
 	if (!error) {
-		setattr_copy(&init_user_ns, inode, attr);
+		setattr_copy(&nop_mnt_idmap, inode, attr);
 		mark_inode_dirty(inode);
 	}
 

fs/reiserfs/reiserfs.h

···
 }
 
 void sd_attrs_to_i_attrs(__u16 sd_attrs, struct inode *inode);
-int reiserfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int reiserfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		     struct iattr *attr);
 
 int __reiserfs_write_begin(struct page *page, unsigned from, unsigned len);

fs/reiserfs/xattr.c

···
 	 * ATTR_MODE is set.
 	 */
 	attrs->ia_valid &= (ATTR_UID|ATTR_GID);
-	err = reiserfs_setattr(&init_user_ns, dentry, attrs);
+	err = reiserfs_setattr(&nop_mnt_idmap, dentry, attrs);
 	attrs->ia_valid = ia_valid;
 
 	return err;
···
 		inode_lock_nested(d_inode(dentry), I_MUTEX_XATTR);
 		inode_dio_wait(d_inode(dentry));
 
-		err = reiserfs_setattr(&init_user_ns, dentry, &newattrs);
+		err = reiserfs_setattr(&nop_mnt_idmap, dentry, &newattrs);
 		inode_unlock(d_inode(dentry));
 	} else
 		update_ctime(inode);

fs/sysv/file.c

···
 	.splice_read	= generic_file_splice_read,
 };
 
-static int sysv_setattr(struct user_namespace *mnt_userns,
+static int sysv_setattr(struct mnt_idmap *idmap,
 			struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
 	int error;
 
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (error)
 		return error;
 
···
 		sysv_truncate(inode);
 	}
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 	return 0;
 }

fs/ubifs/file.c

···
 	return err;
 }
 
-int ubifs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int ubifs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		  struct iattr *attr)
 {
 	int err;
···
 
 	dbg_gen("ino %lu, mode %#x, ia_valid %#x",
 		inode->i_ino, inode->i_mode, attr->ia_valid);
-	err = setattr_prepare(&init_user_ns, dentry, attr);
+	err = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (err)
 		return err;
 

fs/ubifs/ubifs.h

···
 
 /* file.c */
 int ubifs_fsync(struct file *file, loff_t start, loff_t end, int datasync);
-int ubifs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int ubifs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		  struct iattr *attr);
 int ubifs_update_time(struct inode *inode, struct timespec64 *time, int flags);
 

fs/udf/file.c

···
 	.llseek			= generic_file_llseek,
 };
 
-static int udf_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+static int udf_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		       struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
 	struct super_block *sb = inode->i_sb;
 	int error;
 
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (error)
 		return error;
 
···
 	if (attr->ia_valid & ATTR_MODE)
 		udf_update_extra_perms(inode, attr->ia_mode);
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 	return 0;
 }

fs/ufs/inode.c

···
 	return err;
 }
 
-int ufs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int ufs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
 	unsigned int ia_valid = attr->ia_valid;
 	int error;
 
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (error)
 		return error;
 
···
 			return error;
 	}
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 	return 0;
 }

fs/ufs/ufs.h

···
 extern int ufs_write_inode (struct inode *, struct writeback_control *);
 extern int ufs_sync_inode (struct inode *);
 extern void ufs_evict_inode (struct inode *);
-extern int ufs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+extern int ufs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		       struct iattr *attr);
 
 /* namei.c */

fs/vboxsf/utils.c

···
 	return 0;
 }
 
-int vboxsf_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int vboxsf_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		   struct iattr *iattr)
 {
 	struct vboxsf_inode *sf_i = VBOXSF_I(d_inode(dentry));

fs/vboxsf/vfsmod.h

···
 int vboxsf_getattr(struct user_namespace *mnt_userns, const struct path *path,
 		   struct kstat *kstat, u32 request_mask,
 		   unsigned int query_flags);
-int vboxsf_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int vboxsf_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		   struct iattr *iattr);
 struct shfl_string *vboxsf_path_from_dentry(struct vboxsf_sbi *sbi,
 					    struct dentry *dentry);

fs/xfs/xfs_file.c

···
 
 		iattr.ia_valid = ATTR_SIZE;
 		iattr.ia_size = new_size;
-		error = xfs_vn_setattr_size(file_mnt_user_ns(file),
+		error = xfs_vn_setattr_size(file_mnt_idmap(file),
 					    file_dentry(file), &iattr);
 		if (error)
 			goto out_unlock;

fs/xfs/xfs_iops.c

···
 
 static int
 xfs_vn_change_ok(
-	struct user_namespace	*mnt_userns,
+	struct mnt_idmap	*idmap,
 	struct dentry		*dentry,
 	struct iattr		*iattr)
 {
···
 	if (xfs_is_shutdown(mp))
 		return -EIO;
 
-	return setattr_prepare(mnt_userns, dentry, iattr);
+	return setattr_prepare(idmap, dentry, iattr);
 }
 
 /*
···
  */
 static int
 xfs_setattr_nonsize(
-	struct user_namespace	*mnt_userns,
+	struct mnt_idmap	*idmap,
 	struct dentry		*dentry,
 	struct xfs_inode	*ip,
 	struct iattr		*iattr)
···
 	kgid_t			gid = GLOBAL_ROOT_GID;
 	struct xfs_dquot	*udqp = NULL, *gdqp = NULL;
 	struct xfs_dquot	*old_udqp = NULL, *old_gdqp = NULL;
+	struct user_namespace	*mnt_userns = mnt_idmap_owner(idmap);
 
 	ASSERT((mask & ATTR_SIZE) == 0);
 
···
 		old_gdqp = xfs_qm_vop_chown(tp, ip, &ip->i_gdquot, gdqp);
 	}
 
-	setattr_copy(mnt_userns, inode, iattr);
+	setattr_copy(idmap, inode, iattr);
 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 
 	XFS_STATS_INC(mp, xs_ig_attrchg);
···
  */
 STATIC int
 xfs_setattr_size(
-	struct user_namespace	*mnt_userns,
+	struct mnt_idmap	*idmap,
 	struct dentry		*dentry,
 	struct xfs_inode	*ip,
 	struct iattr		*iattr)
···
 		 * Use the regular setattr path to update the timestamps.
 		 */
 		iattr->ia_valid &= ~ATTR_SIZE;
-		return xfs_setattr_nonsize(mnt_userns, dentry, ip, iattr);
+		return xfs_setattr_nonsize(idmap, dentry, ip, iattr);
 	}
 
 	/*
···
 	}
 
 	ASSERT(!(iattr->ia_valid & (ATTR_UID | ATTR_GID)));
-	setattr_copy(mnt_userns, inode, iattr);
+	setattr_copy(idmap, inode, iattr);
 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 
 	XFS_STATS_INC(mp, xs_ig_attrchg);
···
 
 int
 xfs_vn_setattr_size(
-	struct user_namespace	*mnt_userns,
+	struct mnt_idmap	*idmap,
 	struct dentry		*dentry,
 	struct iattr		*iattr)
 {
···
 
 	trace_xfs_setattr(ip);
 
-	error = xfs_vn_change_ok(mnt_userns, dentry, iattr);
+	error = xfs_vn_change_ok(idmap, dentry, iattr);
 	if (error)
 		return error;
-	return xfs_setattr_size(mnt_userns, dentry, ip, iattr);
+	return xfs_setattr_size(idmap, dentry, ip, iattr);
 }
 
 STATIC int
 xfs_vn_setattr(
-	struct user_namespace	*mnt_userns,
+	struct mnt_idmap	*idmap,
 	struct dentry		*dentry,
 	struct iattr		*iattr)
 {
···
 			return error;
 		}
 
-		error = xfs_vn_setattr_size(mnt_userns, dentry, iattr);
+		error = xfs_vn_setattr_size(idmap, dentry, iattr);
 		xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
 	} else {
 		trace_xfs_setattr(ip);
 
-		error = xfs_vn_change_ok(mnt_userns, dentry, iattr);
+		error = xfs_vn_change_ok(idmap, dentry, iattr);
 		if (!error)
-			error = xfs_setattr_nonsize(mnt_userns, dentry, ip, iattr);
+			error = xfs_setattr_nonsize(idmap, dentry, ip, iattr);
 	}
 
 	return error;

fs/xfs/xfs_iops.h

···
 
 extern ssize_t xfs_vn_listxattr(struct dentry *, char *data, size_t size);
 
-int xfs_vn_setattr_size(struct user_namespace *mnt_userns,
+int xfs_vn_setattr_size(struct mnt_idmap *idmap,
 		struct dentry *dentry, struct iattr *vap);
 
 int xfs_inode_init_security(struct inode *inode, struct inode *dir,

fs/xfs/xfs_pnfs.c

···
 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 
 	ASSERT(!(iattr->ia_valid & (ATTR_UID | ATTR_GID)));
-	setattr_copy(&init_user_ns, inode, iattr);
+	setattr_copy(&nop_mnt_idmap, inode, iattr);
 	if (update_isize) {
 		i_size_write(inode, iattr->ia_size);
 		ip->i_disk_size = iattr->ia_size;

fs/zonefs/super.c

···
 	return ret;
 }
 
-static int zonefs_inode_setattr(struct user_namespace *mnt_userns,
+static int zonefs_inode_setattr(struct mnt_idmap *idmap,
 				struct dentry *dentry, struct iattr *iattr)
 {
 	struct inode *inode = d_inode(dentry);
···
 	if (unlikely(IS_IMMUTABLE(inode)))
 		return -EPERM;
 
-	ret = setattr_prepare(&init_user_ns, dentry, iattr);
+	ret = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
 	if (ret)
 		return ret;
 
···
 	     !uid_eq(iattr->ia_uid, inode->i_uid)) ||
 	    ((iattr->ia_valid & ATTR_GID) &&
 	     !gid_eq(iattr->ia_gid, inode->i_gid))) {
-		ret = dquot_transfer(mnt_userns, inode, iattr);
+		ret = dquot_transfer(&init_user_ns, inode, iattr);
 		if (ret)
 			return ret;
 	}
···
 			return ret;
 	}
 
-	setattr_copy(&init_user_ns, inode, iattr);
+	setattr_copy(&nop_mnt_idmap, inode, iattr);
 
 	return 0;
 }

include/linux/evm.h

···
 					     void *xattr_value,
 					     size_t xattr_value_len,
 					     struct integrity_iint_cache *iint);
-extern int evm_inode_setattr(struct user_namespace *mnt_userns,
+extern int evm_inode_setattr(struct mnt_idmap *idmap,
 			     struct dentry *dentry, struct iattr *attr);
 extern void evm_inode_post_setattr(struct dentry *dentry, int ia_valid);
 extern int evm_inode_setxattr(struct user_namespace *mnt_userns,
···
 }
 #endif
 
-static inline int evm_inode_setattr(struct user_namespace *mnt_userns,
+static inline int evm_inode_setattr(struct mnt_idmap *idmap,
 				    struct dentry *dentry, struct iattr *attr)
 {
 	return 0;

include/linux/fs.h

···
 		      umode_t,dev_t);
 	int (*rename) (struct user_namespace *, struct inode *, struct dentry *,
 			struct inode *, struct dentry *, unsigned int);
-	int (*setattr) (struct user_namespace *, struct dentry *,
-			struct iattr *);
+	int (*setattr) (struct mnt_idmap *, struct dentry *, struct iattr *);
 	int (*getattr) (struct user_namespace *, const struct path *,
 			struct kstat *, u32, unsigned int);
 	ssize_t (*listxattr) (struct dentry *, char *, size_t);
···
 extern int dcache_dir_close(struct inode *, struct file *);
 extern loff_t dcache_dir_lseek(struct file *, loff_t, int);
 extern int dcache_readdir(struct file *, struct dir_context *);
-extern int simple_setattr(struct user_namespace *, struct dentry *,
+extern int simple_setattr(struct mnt_idmap *, struct dentry *,
 			  struct iattr *);
 extern int simple_getattr(struct user_namespace *, const struct path *,
 			  struct kstat *, u32, unsigned int);
···
 
 int may_setattr(struct user_namespace *mnt_userns, struct inode *inode,
 		unsigned int ia_valid);
-int setattr_prepare(struct user_namespace *, struct dentry *, struct iattr *);
+int setattr_prepare(struct mnt_idmap *, struct dentry *, struct iattr *);
 extern int inode_newsize_ok(const struct inode *, loff_t offset);
-void setattr_copy(struct user_namespace *, struct inode *inode,
+void setattr_copy(struct mnt_idmap *, struct inode *inode,
 		  const struct iattr *attr);
 
 extern int file_update_time(struct file *file);

include/linux/nfs_fs.h

···
 extern bool nfs_mapping_need_revalidate_inode(struct inode *inode);
 extern int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping);
 extern int nfs_revalidate_mapping_rcu(struct inode *inode);
-extern int nfs_setattr(struct user_namespace *, struct dentry *, struct iattr *);
+extern int nfs_setattr(struct mnt_idmap *, struct dentry *, struct iattr *);
 extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr, struct nfs_fattr *);
 extern void nfs_setsecurity(struct inode *inode, struct nfs_fattr *fattr);
 extern struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx);

include/linux/security.h

···
 int security_inode_follow_link(struct dentry *dentry, struct inode *inode,
 			       bool rcu);
 int security_inode_permission(struct inode *inode, int mask);
-int security_inode_setattr(struct user_namespace *mnt_userns,
+int security_inode_setattr(struct mnt_idmap *idmap,
 			   struct dentry *dentry, struct iattr *attr);
 int security_inode_getattr(const struct path *path);
 int security_inode_setxattr(struct user_namespace *mnt_userns,
···
 	return 0;
 }
 
-static inline int security_inode_setattr(struct user_namespace *mnt_userns,
+static inline int security_inode_setattr(struct mnt_idmap *idmap,
 					 struct dentry *dentry,
 					 struct iattr *attr)
 {

mm/secretmem.c

···
 	.migrate_folio	= secretmem_migrate_folio,
 };
 
-static int secretmem_setattr(struct user_namespace *mnt_userns,
+static int secretmem_setattr(struct mnt_idmap *idmap,
 			     struct dentry *dentry, struct iattr *iattr)
 {
 	struct inode *inode = d_inode(dentry);
···
 	if ((ia_valid & ATTR_SIZE) && inode->i_size)
 		ret = -EINVAL;
 	else
-		ret = simple_setattr(mnt_userns, dentry, iattr);
+		ret = simple_setattr(idmap, dentry, iattr);
 
 	filemap_invalidate_unlock(mapping);
 

mm/shmem.c

···
 	return 0;
 }
 
-static int shmem_setattr(struct user_namespace *mnt_userns,
+static int shmem_setattr(struct mnt_idmap *idmap,
 			 struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
···
 	bool update_mtime = false;
 	bool update_ctime = true;
 
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (error)
 		return error;
 
···
 		}
 	}
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	if (attr->ia_valid & ATTR_MODE)
 		error = posix_acl_chmod(&init_user_ns, dentry, inode->i_mode);
 	if (!error && update_ctime) {

net/socket.c

···
 	return used;
 }
 
-static int sockfs_setattr(struct user_namespace *mnt_userns,
+static int sockfs_setattr(struct mnt_idmap *idmap,
 			  struct dentry *dentry, struct iattr *iattr)
 {
-	int err = simple_setattr(&init_user_ns, dentry, iattr);
+	int err = simple_setattr(&nop_mnt_idmap, dentry, iattr);
 
 	if (!err && (iattr->ia_valid & ATTR_UID)) {
 		struct socket *sock = SOCKET_I(d_inode(dentry));

security/integrity/evm/evm_main.c

···
 	evm_update_evmxattr(dentry, xattr_name, NULL, 0);
 }
 
-static int evm_attr_change(struct user_namespace *mnt_userns,
+static int evm_attr_change(struct mnt_idmap *idmap,
 			   struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = d_backing_inode(dentry);
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	unsigned int ia_valid = attr->ia_valid;
 
 	if (!i_uid_needs_update(mnt_userns, attr, inode) &&
···
  * Permit update of file attributes when files have a valid EVM signature,
  * except in the case of them having an immutable portable signature.
  */
-int evm_inode_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int evm_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		      struct iattr *attr)
 {
 	unsigned int ia_valid = attr->ia_valid;
···
 		return 0;
 
 	if (evm_status == INTEGRITY_PASS_IMMUTABLE &&
-	    !evm_attr_change(mnt_userns, dentry, attr))
+	    !evm_attr_change(idmap, dentry, attr))
 		return 0;
 
 	integrity_audit_msg(AUDIT_INTEGRITY_METADATA, d_backing_inode(dentry),

security/integrity/evm/evm_secfs.c

···
 		newattrs.ia_valid = ATTR_MODE;
 		inode = evm_xattrs->d_inode;
 		inode_lock(inode);
-		err = simple_setattr(&init_user_ns, evm_xattrs, &newattrs);
+		err = simple_setattr(&nop_mnt_idmap, evm_xattrs, &newattrs);
 		inode_unlock(inode);
 		if (!err)
 			err = count;

security/security.c

···
 	return call_int_hook(inode_permission, 0, inode, mask);
 }
 
-int security_inode_setattr(struct user_namespace *mnt_userns,
+int security_inode_setattr(struct mnt_idmap *idmap,
 			   struct dentry *dentry, struct iattr *attr)
 {
 	int ret;
···
 	ret = call_int_hook(inode_setattr, 0, dentry, attr);
 	if (ret)
 		return ret;
-	return evm_inode_setattr(mnt_userns, dentry, attr);
+	return evm_inode_setattr(idmap, dentry, attr);
 }
 EXPORT_SYMBOL_GPL(security_inode_setattr);