Support idmapped mount in user namespace

Linux 5.17 commit torvalds/linux@5dfbfe71e enables "the idmapping 
infrastructure to support idmapped mounts of filesystems mounted 
with an idmapping". Update the OpenZFS accordingly to improve the 
idmapped mount support. 

This pull request contains the following changes:

- xattr setter functions are fixed to take mnt_ns argument. Without
  this, cp -p would fail for an idmapped mount in a user namespace.
- idmap_util is enhanced/fixed for its use in a user ns context.
- One test case added to test idmapped mount in a user ns.

Reviewed-by: Christian Brauner <christian@brauner.io>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Youzhong Yang <yyang@mathworks.com>
Closes #14097

module/os/linux/zfs/policy.c

@@ -214,9 +214,10 @@ secpolicy_vnode_setid_retain(struct znode *zp __maybe_unused, const cred_t *cr,
  * Determine that subject can set the file setgid flag.
  */
 int
-secpolicy_vnode_setids_setgids(const cred_t *cr, gid_t gid, zuserns_t *mnt_ns)
+secpolicy_vnode_setids_setgids(const cred_t *cr, gid_t gid, zuserns_t *mnt_ns,
+    zuserns_t *fs_ns)
 {
-	gid = zfs_gid_into_mnt(mnt_ns, gid);
+	gid = zfs_gid_to_vfsgid(mnt_ns, fs_ns, gid);
 #if defined(CONFIG_USER_NS)
 	if (!kgid_has_mapping(cr->user_ns, SGID_TO_KGID(gid)))
 		return (EPERM);
@@ -285,9 +286,10 @@ secpolicy_setid_clear(vattr_t *vap, cred_t *cr)
  * Determine that subject can set the file setid flags.
  */
 static int
-secpolicy_vnode_setid_modify(const cred_t *cr, uid_t owner, zuserns_t *mnt_ns)
+secpolicy_vnode_setid_modify(const cred_t *cr, uid_t owner, zuserns_t *mnt_ns,
+    zuserns_t *fs_ns)
 {
-	owner = zfs_uid_into_mnt(mnt_ns, owner);
+	owner = zfs_uid_to_vfsuid(mnt_ns, fs_ns, owner);
 
 	if (crgetuid(cr) == owner)
 		return (0);
@@ -313,13 +315,13 @@ secpolicy_vnode_stky_modify(const cred_t *cr)
 
 int
 secpolicy_setid_setsticky_clear(struct inode *ip, vattr_t *vap,
-    const vattr_t *ovap, cred_t *cr, zuserns_t *mnt_ns)
+    const vattr_t *ovap, cred_t *cr, zuserns_t *mnt_ns, zuserns_t *fs_ns)
 {
 	int error;
 
 	if ((vap->va_mode & S_ISUID) != 0 &&
 	    (error = secpolicy_vnode_setid_modify(cr,
-	    ovap->va_uid, mnt_ns)) != 0) {
+	    ovap->va_uid, mnt_ns, fs_ns)) != 0) {
 		return (error);
 	}
 
@@ -337,7 +339,8 @@ secpolicy_setid_setsticky_clear(struct inode *ip, vattr_t *vap,
 	 * group-id bit.
 	 */
 	if ((vap->va_mode & S_ISGID) != 0 &&
-	    secpolicy_vnode_setids_setgids(cr, ovap->va_gid, mnt_ns) != 0) {
+	    secpolicy_vnode_setids_setgids(cr, ovap->va_gid,
+	    mnt_ns, fs_ns) != 0) {
 		vap->va_mode &= ~S_ISGID;
 	}
 

module/os/linux/zfs/zfs_acl.c

@@ -1889,7 +1889,8 @@ zfs_acl_ids_create(znode_t *dzp, int flag, vattr_t *vap, cred_t *cr,
 		acl_ids->z_mode |= S_ISGID;
 	} else {
 		if ((acl_ids->z_mode & S_ISGID) &&
-		    secpolicy_vnode_setids_setgids(cr, gid, mnt_ns) != 0) {
+		    secpolicy_vnode_setids_setgids(cr, gid, mnt_ns,
+		    zfs_i_user_ns(ZTOI(dzp))) != 0) {
 			acl_ids->z_mode &= ~S_ISGID;
 		}
 	}
@@ -1979,7 +1980,8 @@ zfs_getacl(znode_t *zp, vsecattr_t *vsecp, boolean_t skipaclchk, cred_t *cr)
 	if (mask == 0)
 		return (SET_ERROR(ENOSYS));
 
-	if ((error = zfs_zaccess(zp, ACE_READ_ACL, 0, skipaclchk, cr, NULL)))
+	if ((error = zfs_zaccess(zp, ACE_READ_ACL, 0, skipaclchk, cr,
+	    kcred->user_ns)))
 		return (error);
 
 	mutex_enter(&zp->z_acl_lock);
@@ -2138,7 +2140,8 @@ zfs_setacl(znode_t *zp, vsecattr_t *vsecp, boolean_t skipaclchk, cred_t *cr)
 	if (zp->z_pflags & ZFS_IMMUTABLE)
 		return (SET_ERROR(EPERM));
 
-	if ((error = zfs_zaccess(zp, ACE_WRITE_ACL, 0, skipaclchk, cr, NULL)))
+	if ((error = zfs_zaccess(zp, ACE_WRITE_ACL, 0, skipaclchk, cr,
+	    kcred->user_ns)))
 		return (error);
 
 	error = zfs_vsec_2_aclp(zfsvfs, ZTOI(zp)->i_mode, vsecp, cr, &fuidp,
@@ -2301,9 +2304,9 @@ zfs_zaccess_aces_check(znode_t *zp, uint32_t *working_mode,
 	uid_t		fowner;
 
 	if (mnt_ns) {
-		fowner = zfs_uid_into_mnt(mnt_ns,
+		fowner = zfs_uid_to_vfsuid(mnt_ns, zfs_i_user_ns(ZTOI(zp)),
 		    KUID_TO_SUID(ZTOI(zp)->i_uid));
-		gowner = zfs_gid_into_mnt(mnt_ns,
+		gowner = zfs_gid_to_vfsgid(mnt_ns, zfs_i_user_ns(ZTOI(zp)),
 		    KGID_TO_SGID(ZTOI(zp)->i_gid));
 	} else
 		zfs_fuid_map_ids(zp, cr, &fowner, &gowner);
@@ -2417,7 +2420,8 @@ zfs_has_access(znode_t *zp, cred_t *cr)
 {
 	uint32_t have = ACE_ALL_PERMS;
 
-	if (zfs_zaccess_aces_check(zp, &have, B_TRUE, cr, NULL) != 0) {
+	if (zfs_zaccess_aces_check(zp, &have, B_TRUE, cr,
+	    kcred->user_ns) != 0) {
 		uid_t owner;
 
 		owner = zfs_fuid_map_id(ZTOZSB(zp),
@@ -2610,7 +2614,8 @@ slow:
 	DTRACE_PROBE(zfs__fastpath__execute__access__miss);
 	if ((error = zfs_enter(ZTOZSB(zdp), FTAG)) != 0)
 		return (error);
-	error = zfs_zaccess(zdp, ACE_EXECUTE, 0, B_FALSE, cr, NULL);
+	error = zfs_zaccess(zdp, ACE_EXECUTE, 0, B_FALSE, cr,
+	    kcred->user_ns);
 	zfs_exit(ZTOZSB(zdp), FTAG);
 	return (error);
 }
@@ -2662,7 +2667,8 @@ zfs_zaccess(znode_t *zp, int mode, int flags, boolean_t skipaclchk, cred_t *cr,
 		}
 	}
 
-	owner = zfs_uid_into_mnt(mnt_ns, KUID_TO_SUID(ZTOI(zp)->i_uid));
+	owner = zfs_uid_to_vfsuid(mnt_ns, zfs_i_user_ns(ZTOI(zp)),
+	    KUID_TO_SUID(ZTOI(zp)->i_uid));
 	owner = zfs_fuid_map_id(ZTOZSB(zp), owner, cr, ZFS_OWNER);
 
 	/*
@@ -2786,7 +2792,7 @@ zfs_zaccess_unix(znode_t *zp, mode_t mode, cred_t *cr)
 {
 	int v4_mode = zfs_unix_to_v4(mode >> 6);
 
-	return (zfs_zaccess(zp, v4_mode, 0, B_FALSE, cr, NULL));
+	return (zfs_zaccess(zp, v4_mode, 0, B_FALSE, cr, kcred->user_ns));
 }
 
 /* See zfs_zaccess_delete() */

module/os/linux/zfs/zfs_dir.c

@@ -1113,11 +1113,11 @@ zfs_make_xattrdir(znode_t *zp, vattr_t *vap, znode_t **xzpp, cred_t *cr)
 	*xzpp = NULL;
 
 	if ((error = zfs_zaccess(zp, ACE_WRITE_NAMED_ATTRS, 0, B_FALSE, cr,
-	    NULL)))
+	    kcred->user_ns)))
 		return (error);
 
 	if ((error = zfs_acl_ids_create(zp, IS_XATTR, vap, cr, NULL,
-	    &acl_ids, NULL)) != 0)
+	    &acl_ids, kcred->user_ns)) != 0)
 		return (error);
 	if (zfs_acl_ids_overquota(zfsvfs, &acl_ids, zp->z_projid)) {
 		zfs_acl_ids_free(&acl_ids);
@@ -1265,7 +1265,8 @@ zfs_sticky_remove_access(znode_t *zdp, znode_t *zp, cred_t *cr)
 	    cr, ZFS_OWNER);
 
 	if ((uid = crgetuid(cr)) == downer || uid == fowner ||
-	    zfs_zaccess(zp, ACE_WRITE_DATA, 0, B_FALSE, cr, NULL) == 0)
+	    zfs_zaccess(zp, ACE_WRITE_DATA, 0, B_FALSE, cr,
+	    kcred->user_ns) == 0)
 		return (0);
 	else
 		return (secpolicy_vnode_remove(cr));

module/os/linux/zfs/zfs_vnops_os.c

@@ -476,7 +476,7 @@ zfs_lookup(znode_t *zdp, char *nm, znode_t **zpp, int flags, cred_t *cr,
 		 */
 
 		if ((error = zfs_zaccess(*zpp, ACE_EXECUTE, 0,
-		    B_TRUE, cr, NULL))) {
+		    B_TRUE, cr, kcred->user_ns))) {
 			zrele(*zpp);
 			*zpp = NULL;
 		}
@@ -494,7 +494,8 @@ zfs_lookup(znode_t *zdp, char *nm, znode_t **zpp, int flags, cred_t *cr,
 	 * Check accessibility of directory.
 	 */
 
-	if ((error = zfs_zaccess(zdp, ACE_EXECUTE, 0, B_FALSE, cr, NULL))) {
+	if ((error = zfs_zaccess(zdp, ACE_EXECUTE, 0, B_FALSE, cr,
+	    kcred->user_ns))) {
 		zfs_exit(zfsvfs, FTAG);
 		return (error);
 	}
@@ -972,7 +973,7 @@ top:
 		return (error);
 	}
 
-	if ((error = zfs_zaccess_delete(dzp, zp, cr, NULL))) {
+	if ((error = zfs_zaccess_delete(dzp, zp, cr, kcred->user_ns))) {
 		goto out;
 	}
 
@@ -1386,7 +1387,7 @@ top:
 		return (error);
 	}
 
-	if ((error = zfs_zaccess_delete(dzp, zp, cr, NULL))) {
+	if ((error = zfs_zaccess_delete(dzp, zp, cr, kcred->user_ns))) {
 		goto out;
 	}
 
@@ -2024,10 +2025,10 @@ top:
 		 * Take ownership or chgrp to group we are a member of
 		 */
 
-		uid = zfs_uid_into_mnt((struct user_namespace *)mnt_ns,
-		    vap->va_uid);
-		gid = zfs_gid_into_mnt((struct user_namespace *)mnt_ns,
-		    vap->va_gid);
+		uid = zfs_uid_to_vfsuid((struct user_namespace *)mnt_ns,
+		    zfs_i_user_ns(ip), vap->va_uid);
+		gid = zfs_gid_to_vfsgid((struct user_namespace *)mnt_ns,
+		    zfs_i_user_ns(ip), vap->va_gid);
 		take_owner = (mask & ATTR_UID) && (uid == crgetuid(cr));
 		take_group = (mask & ATTR_GID) &&
 		    zfs_groupmember(zfsvfs, gid, cr);
@@ -2162,7 +2163,7 @@ top:
 		if (zfs_zaccess(zp, ACE_WRITE_ACL, 0, skipaclchk, cr,
 		    mnt_ns) == 0) {
 			err = secpolicy_setid_setsticky_clear(ip, vap,
-			    &oldva, cr, mnt_ns);
+			    &oldva, cr, mnt_ns, zfs_i_user_ns(ip));
 			if (err)
 				goto out3;
 			trim_mask |= ATTR_MODE;
@@ -3506,7 +3507,8 @@ zfs_link(znode_t *tdzp, znode_t *szp, char *name, cred_t *cr,
 		return (SET_ERROR(EPERM));
 	}
 
-	if ((error = zfs_zaccess(tdzp, ACE_ADD_FILE, 0, B_FALSE, cr, NULL))) {
+	if ((error = zfs_zaccess(tdzp, ACE_ADD_FILE, 0, B_FALSE, cr,
+	    kcred->user_ns))) {
 		zfs_exit(zfsvfs, FTAG);
 		return (error);
 	}
@@ -4132,7 +4134,8 @@ zfs_space(znode_t *zp, int cmd, flock64_t *bfp, int flag,
 	 * On Linux we can get here through truncate_range() which
 	 * operates directly on inodes, so we need to check access rights.
 	 */
-	if ((error = zfs_zaccess(zp, ACE_WRITE_DATA, 0, B_FALSE, cr, NULL))) {
+	if ((error = zfs_zaccess(zp, ACE_WRITE_DATA, 0, B_FALSE, cr,
+	    kcred->user_ns))) {
 		zfs_exit(zfsvfs, FTAG);
 		return (error);
 	}

module/os/linux/zfs/zfs_znode.c

@@ -1964,7 +1964,7 @@ zfs_create_fs(objset_t *os, cred_t *cr, nvlist_t *zplprops, dmu_tx_t *tx)
 	}
 
 	VERIFY(0 == zfs_acl_ids_create(rootzp, IS_ROOT_NODE, &vattr,
-	    cr, NULL, &acl_ids, NULL));
+	    cr, NULL, &acl_ids, kcred->user_ns));
 	zfs_mknode(rootzp, &vattr, tx, cr, IS_ROOT_NODE, &zp, &acl_ids);
 	ASSERT3P(zp, ==, rootzp);
 	error = zap_add(os, moid, ZFS_ROOT_OBJ, 8, 1, &rootzp->z_id, tx);

module/os/linux/zfs/zpl_ctldir.c

@@ -374,7 +374,7 @@ zpl_snapdir_mkdir(struct inode *dip, struct dentry *dentry, umode_t mode)
 #ifdef HAVE_IOPS_MKDIR_USERNS
 	zpl_vap_init(vap, dip, mode | S_IFDIR, cr, user_ns);
 #else
-	zpl_vap_init(vap, dip, mode | S_IFDIR, cr, NULL);
+	zpl_vap_init(vap, dip, mode | S_IFDIR, cr, kcred->user_ns);
 #endif
 
 	error = -zfsctl_snapdir_mkdir(dip, dname(dentry), vap, &ip, cr, 0);

module/os/linux/zfs/zpl_file.c

@@ -1085,7 +1085,7 @@ zpl_ioctl_setflags(struct file *filp, void __user *arg)
 
 	crhold(cr);
 	cookie = spl_fstrans_mark();
-	err = -zfs_setattr(ITOZ(ip), (vattr_t *)&xva, 0, cr, NULL);
+	err = -zfs_setattr(ITOZ(ip), (vattr_t *)&xva, 0, cr, kcred->user_ns);
 	spl_fstrans_unmark(cookie);
 	crfree(cr);
 
@@ -1133,7 +1133,7 @@ zpl_ioctl_setxattr(struct file *filp, void __user *arg)
 
 	crhold(cr);
 	cookie = spl_fstrans_mark();
-	err = -zfs_setattr(ITOZ(ip), (vattr_t *)&xva, 0, cr, NULL);
+	err = -zfs_setattr(ITOZ(ip), (vattr_t *)&xva, 0, cr, kcred->user_ns);
 	spl_fstrans_unmark(cookie);
 	crfree(cr);
 
@@ -1221,7 +1221,7 @@ zpl_ioctl_setdosflags(struct file *filp, void __user *arg)
 
 	crhold(cr);
 	cookie = spl_fstrans_mark();
-	err = -zfs_setattr(ITOZ(ip), (vattr_t *)&xva, 0, cr, NULL);
+	err = -zfs_setattr(ITOZ(ip), (vattr_t *)&xva, 0, cr, kcred->user_ns);
 	spl_fstrans_unmark(cookie);
 	crfree(cr);
 

module/os/linux/zfs/zpl_inode.c

@@ -118,16 +118,16 @@ zpl_vap_init(vattr_t *vap, struct inode *dir, umode_t mode, cred_t *cr,
 	vap->va_mask = ATTR_MODE;
 	vap->va_mode = mode;
 
-	vap->va_uid = zfs_uid_from_mnt((struct user_namespace *)mnt_ns,
-	    crgetuid(cr));
+	vap->va_uid = zfs_vfsuid_to_uid((struct user_namespace *)mnt_ns,
+	    zfs_i_user_ns(dir), crgetuid(cr));
 
 	if (dir && dir->i_mode & S_ISGID) {
 		vap->va_gid = KGID_TO_SGID(dir->i_gid);
 		if (S_ISDIR(mode))
 			vap->va_mode |= S_ISGID;
 	} else {
-		vap->va_gid = zfs_gid_from_mnt((struct user_namespace *)mnt_ns,
-		    crgetgid(cr));
+		vap->va_gid = zfs_vfsgid_to_gid((struct user_namespace *)mnt_ns,
+		    zfs_i_user_ns(dir), crgetgid(cr));
 	}
 }
 
@@ -145,7 +145,7 @@ zpl_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool flag)
 	int error;
 	fstrans_cookie_t cookie;
 #ifndef HAVE_IOPS_CREATE_USERNS
-	zuserns_t *user_ns = NULL;
+	zuserns_t *user_ns = kcred->user_ns;
 #endif
 
 	crhold(cr);
@@ -192,7 +192,7 @@ zpl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
 	int error;
 	fstrans_cookie_t cookie;
 #ifndef HAVE_IOPS_MKNOD_USERNS
-	zuserns_t *user_ns = NULL;
+	zuserns_t *user_ns = kcred->user_ns;
 #endif
 
 	/*
@@ -247,7 +247,7 @@ zpl_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
 	int error;
 	fstrans_cookie_t cookie;
 #ifndef HAVE_TMPFILE_USERNS
-	zuserns_t *userns = NULL;
+	zuserns_t *userns = kcred->user_ns;
 #endif
 
 	crhold(cr);
@@ -325,7 +325,7 @@ zpl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 	int error;
 	fstrans_cookie_t cookie;
 #ifndef HAVE_IOPS_MKDIR_USERNS
-	zuserns_t *user_ns = NULL;
+	zuserns_t *user_ns = kcred->user_ns;
 #endif
 
 	crhold(cr);
@@ -468,8 +468,20 @@ zpl_setattr(struct dentry *dentry, struct iattr *ia)
 	vap = kmem_zalloc(sizeof (vattr_t), KM_SLEEP);
 	vap->va_mask = ia->ia_valid & ATTR_IATTR_MASK;
 	vap->va_mode = ia->ia_mode;
-	vap->va_uid = KUID_TO_SUID(ia->ia_uid);
-	vap->va_gid = KGID_TO_SGID(ia->ia_gid);
+	if (ia->ia_valid & ATTR_UID)
+#ifdef HAVE_IATTR_VFSID
+		vap->va_uid = zfs_vfsuid_to_uid(user_ns, zfs_i_user_ns(ip),
+		    __vfsuid_val(ia->ia_vfsuid));
+#else
+		vap->va_uid = KUID_TO_SUID(ia->ia_uid);
+#endif
+	if (ia->ia_valid & ATTR_GID)
+#ifdef HAVE_IATTR_VFSID
+		vap->va_gid = zfs_vfsgid_to_gid(user_ns, zfs_i_user_ns(ip),
+		    __vfsgid_val(ia->ia_vfsgid));
+#else
+		vap->va_gid = KGID_TO_SGID(ia->ia_gid);
+#endif
 	vap->va_size = ia->ia_size;
 	vap->va_atime = ia->ia_atime;
 	vap->va_mtime = ia->ia_mtime;
@@ -482,7 +494,7 @@ zpl_setattr(struct dentry *dentry, struct iattr *ia)
 #ifdef HAVE_SETATTR_PREPARE_USERNS
 	error = -zfs_setattr(ITOZ(ip), vap, 0, cr, user_ns);
 #else
-	error = -zfs_setattr(ITOZ(ip), vap, 0, cr, NULL);
+	error = -zfs_setattr(ITOZ(ip), vap, 0, cr, kcred->user_ns);
 #endif
 	if (!error && (ia->ia_valid & ATTR_MODE))
 		error = zpl_chmod_acl(ip);
@@ -510,7 +522,7 @@ zpl_rename2(struct inode *sdip, struct dentry *sdentry,
 	int error;
 	fstrans_cookie_t cookie;
 #ifndef HAVE_IOPS_RENAME_USERNS
-	zuserns_t *user_ns = NULL;
+	zuserns_t *user_ns = kcred->user_ns;
 #endif
 
 	crhold(cr);
@@ -557,7 +569,7 @@ zpl_symlink(struct inode *dir, struct dentry *dentry, const char *name)
 	int error;
 	fstrans_cookie_t cookie;
 #ifndef HAVE_IOPS_SYMLINK_USERNS
-	zuserns_t *user_ns = NULL;
+	zuserns_t *user_ns = kcred->user_ns;
 #endif
 
 	crhold(cr);

module/os/linux/zfs/zpl_xattr.c

@@ -499,7 +499,7 @@ zpl_xattr_set_dir(struct inode *ip, const char *name, const void *value,
 		vap->va_gid = crgetgid(cr);
 
 		error = -zfs_create(dxzp, (char *)name, vap, 0, 0644, &xzp,
-		    cr, 0, NULL, NULL);
+		    cr, 0, NULL, kcred->user_ns);
 		if (error)
 			goto out;
 	}
@@ -738,9 +738,11 @@ __zpl_xattr_user_get(struct inode *ip, const char *name,
 ZPL_XATTR_GET_WRAPPER(zpl_xattr_user_get);
 
 static int
-__zpl_xattr_user_set(struct inode *ip, const char *name,
+__zpl_xattr_user_set(struct user_namespace *user_ns,
+    struct inode *ip, const char *name,
     const void *value, size_t size, int flags)
 {
+	(void) user_ns;
 	int error = 0;
 	/* xattr_resolve_name will do this for us if this is defined */
 #ifndef HAVE_XATTR_HANDLER_NAME
@@ -846,9 +848,11 @@ __zpl_xattr_trusted_get(struct inode *ip, const char *name,
 ZPL_XATTR_GET_WRAPPER(zpl_xattr_trusted_get);
 
 static int
-__zpl_xattr_trusted_set(struct inode *ip, const char *name,
+__zpl_xattr_trusted_set(struct user_namespace *user_ns,
+    struct inode *ip, const char *name,
     const void *value, size_t size, int flags)
 {
+	(void) user_ns;
 	char *xattr_name;
 	int error;
 
@@ -914,9 +918,11 @@ __zpl_xattr_security_get(struct inode *ip, const char *name,
 ZPL_XATTR_GET_WRAPPER(zpl_xattr_security_get);
 
 static int
-__zpl_xattr_security_set(struct inode *ip, const char *name,
+__zpl_xattr_security_set(struct user_namespace *user_ns,
+    struct inode *ip, const char *name,
     const void *value, size_t size, int flags)
 {
+	(void) user_ns;
 	char *xattr_name;
 	int error;
 	/* xattr_resolve_name will do this for us if this is defined */
@@ -940,7 +946,7 @@ zpl_xattr_security_init_impl(struct inode *ip, const struct xattr *xattrs,
 	int error = 0;
 
 	for (xattr = xattrs; xattr->name != NULL; xattr++) {
-		error = __zpl_xattr_security_set(ip,
+		error = __zpl_xattr_security_set(NULL, ip,
 		    xattr->name, xattr->value, xattr->value_len, 0);
 
 		if (error < 0)
@@ -1300,7 +1306,8 @@ __zpl_xattr_acl_get_default(struct inode *ip, const char *name,
 ZPL_XATTR_GET_WRAPPER(zpl_xattr_acl_get_default);
 
 static int
-__zpl_xattr_acl_set_access(struct inode *ip, const char *name,
+__zpl_xattr_acl_set_access(struct user_namespace *mnt_ns,
+    struct inode *ip, const char *name,
     const void *value, size_t size, int flags)
 {
 	struct posix_acl *acl;
@@ -1314,8 +1321,14 @@ __zpl_xattr_acl_set_access(struct inode *ip, const char *name,
 	if (ITOZSB(ip)->z_acl_type != ZFS_ACLTYPE_POSIX)
 		return (-EOPNOTSUPP);
 
+#if defined(HAVE_XATTR_SET_USERNS)
+	if (!zpl_inode_owner_or_capable(mnt_ns, ip))
+		return (-EPERM);
+#else
+	(void) mnt_ns;
 	if (!zpl_inode_owner_or_capable(kcred->user_ns, ip))
 		return (-EPERM);
+#endif
 
 	if (value) {
 		acl = zpl_acl_from_xattr(value, size);
@@ -1339,7 +1352,8 @@ __zpl_xattr_acl_set_access(struct inode *ip, const char *name,
 ZPL_XATTR_SET_WRAPPER(zpl_xattr_acl_set_access);
 
 static int
-__zpl_xattr_acl_set_default(struct inode *ip, const char *name,
+__zpl_xattr_acl_set_default(struct user_namespace *mnt_ns,
+    struct inode *ip, const char *name,
     const void *value, size_t size, int flags)
 {
 	struct posix_acl *acl;
@@ -1353,8 +1367,14 @@ __zpl_xattr_acl_set_default(struct inode *ip, const char *name,
 	if (ITOZSB(ip)->z_acl_type != ZFS_ACLTYPE_POSIX)
 		return (-EOPNOTSUPP);
 
+#if defined(HAVE_XATTR_SET_USERNS)
+	if (!zpl_inode_owner_or_capable(mnt_ns, ip))
+		return (-EPERM);
+#else
+	(void) mnt_ns;
 	if (!zpl_inode_owner_or_capable(kcred->user_ns, ip))
 		return (-EPERM);
+#endif
 
 	if (value) {
 		acl = zpl_acl_from_xattr(value, size);

module/zfs/zfs_replay.c

@@ -386,8 +386,13 @@ zfs_replay_create_acl(void *arg1, void *arg2, boolean_t byteswap)
 			    lr->lr_uid, lr->lr_gid);
 		}
 
+#if defined(__linux__)
+		error = zfs_create(dzp, name, &xva.xva_vattr,
+		    0, 0, &zp, kcred, vflg, &vsec, kcred->user_ns);
+#else
 		error = zfs_create(dzp, name, &xva.xva_vattr,
 		    0, 0, &zp, kcred, vflg, &vsec, NULL);
+#endif
 		break;
 	case TX_MKDIR_ACL:
 		aclstart = (caddr_t)(lracl + 1);
@@ -416,8 +421,13 @@ zfs_replay_create_acl(void *arg1, void *arg2, boolean_t byteswap)
 			    (void *)&name, lracl->lr_fuidcnt, lracl->lr_domcnt,
 			    lr->lr_uid, lr->lr_gid);
 		}
+#if defined(__linux__)
+		error = zfs_mkdir(dzp, name, &xva.xva_vattr,
+		    &zp, kcred, vflg, &vsec, kcred->user_ns);
+#else
 		error = zfs_mkdir(dzp, name, &xva.xva_vattr,
 		    &zp, kcred, vflg, &vsec, NULL);
+#endif
 		break;
 	default:
 		error = SET_ERROR(ENOTSUP);
@@ -527,8 +537,13 @@ zfs_replay_create(void *arg1, void *arg2, boolean_t byteswap)
 		if (name == NULL)
 			name = (char *)start;
 
+#if defined(__linux__)
+		error = zfs_create(dzp, name, &xva.xva_vattr,
+		    0, 0, &zp, kcred, vflg, NULL, kcred->user_ns);
+#else
 		error = zfs_create(dzp, name, &xva.xva_vattr,
 		    0, 0, &zp, kcred, vflg, NULL, NULL);
+#endif
 		break;
 	case TX_MKDIR_ATTR:
 		lrattr = (lr_attr_t *)(caddr_t)(lr + 1);
@@ -545,8 +560,14 @@ zfs_replay_create(void *arg1, void *arg2, boolean_t byteswap)
 		if (name == NULL)
 			name = (char *)(lr + 1);
 
+#if defined(__linux__)
+		error = zfs_mkdir(dzp, name, &xva.xva_vattr,
+		    &zp, kcred, vflg, NULL, kcred->user_ns);
+#else
 		error = zfs_mkdir(dzp, name, &xva.xva_vattr,
 		    &zp, kcred, vflg, NULL, NULL);
+#endif
+
 		break;
 	case TX_MKXATTR:
 		error = zfs_make_xattrdir(dzp, &xva.xva_vattr, &zp, kcred);
@@ -554,8 +575,13 @@ zfs_replay_create(void *arg1, void *arg2, boolean_t byteswap)
 	case TX_SYMLINK:
 		name = (char *)(lr + 1);
 		link = name + strlen(name) + 1;
+#if defined(__linux__)
+		error = zfs_symlink(dzp, name, &xva.xva_vattr,
+		    link, &zp, kcred, vflg, kcred->user_ns);
+#else
 		error = zfs_symlink(dzp, name, &xva.xva_vattr,
 		    link, &zp, kcred, vflg, NULL);
+#endif
 		break;
 	default:
 		error = SET_ERROR(ENOTSUP);
@@ -670,8 +696,13 @@ do_zfs_replay_rename(zfsvfs_t *zfsvfs, lr_rename_t *lr, char *sname,
 	if (lr->lr_common.lrc_txtype & TX_CI)
 		vflg |= FIGNORECASE;
 
+#if defined(__linux__)
+	error = zfs_rename(sdzp, sname, tdzp, tname, kcred, vflg, rflags,
+	    wo_vap, kcred->user_ns);
+#else
 	error = zfs_rename(sdzp, sname, tdzp, tname, kcred, vflg, rflags,
 	    wo_vap, NULL);
+#endif
 
 	zrele(tdzp);
 	zrele(sdzp);
@@ -944,7 +975,11 @@ zfs_replay_setattr(void *arg1, void *arg2, boolean_t byteswap)
 	zfsvfs->z_fuid_replay = zfs_replay_fuid_domain(start, &start,
 	    lr->lr_uid, lr->lr_gid);
 
+#if defined(__linux__)
+	error = zfs_setattr(zp, vap, 0, kcred, kcred->user_ns);
+#else
 	error = zfs_setattr(zp, vap, 0, kcred, NULL);
+#endif
 
 	zfs_fuid_info_free(zfsvfs->z_fuid_replay);
 	zfsvfs->z_fuid_replay = NULL;

module/zfs/zfs_vnops.c

@@ -168,9 +168,19 @@ zfs_access(znode_t *zp, int mode, int flag, cred_t *cr)
 		return (error);
 
 	if (flag & V_ACE_MASK)
-		error = zfs_zaccess(zp, mode, flag, B_FALSE, cr, NULL);
+#if defined(__linux__)
+		error = zfs_zaccess(zp, mode, flag, B_FALSE, cr,
+		    kcred->user_ns);
+#else
+		error = zfs_zaccess(zp, mode, flag, B_FALSE, cr,
+		    NULL);
+#endif
 	else
+#if defined(__linux__)
+		error = zfs_zaccess_rwx(zp, mode, flag, cr, kcred->user_ns);
+#else
 		error = zfs_zaccess_rwx(zp, mode, flag, cr, NULL);
+#endif
 
 	zfs_exit(zfsvfs, FTAG);
 	return (error);