diff --git a/kmod/src/Makefile.kernelcompat b/kmod/src/Makefile.kernelcompat
index 68812985..1a9c0da1 100644
--- a/kmod/src/Makefile.kernelcompat
+++ b/kmod/src/Makefile.kernelcompat
@@ -283,6 +283,30 @@ ifneq (,$(shell grep 'extern void .__vmalloc.unsigned long size, gfp_t gfp_mask,
 ccflags-y += -DKC_VMALLOC_PGPROT_T
 endif
 
+# v6.2-rc1-18-g01beba7957a2
+#
+# fs: port inode_owner_or_capable() to mnt_idmap
+ifneq (,$(shell grep 'bool inode_owner_or_capable.struct user_namespace .mnt_userns' include/linux/fs.h))
+ccflags-y += -DKC_INODE_OWNER_OR_CAPABLE_USERNS
+endif
+
+#
+# v5.11-rc4-5-g47291baa8ddf
+#
+# namei: make permission helpers idmapped mount aware
+ifneq (,$(shell grep 'int inode_permission.struct user_namespace' include/linux/fs.h))
+ccflags-y += -DKC_INODE_PERMISSION_USERNS
+endif
+
+#
+# v5.11-rc4-24-g549c7297717c
+#
+# fs: make helpers idmap mount aware
+# Enlarges the VFS API methods to include user namespace argument.
+ifneq (,$(shell grep 'int ..mknod. .struct user_namespace' include/linux/fs.h))
+ccflags-y += -DKC_VFS_METHOD_USER_NAMESPACE_ARG
+endif
+
 #
 # v5.17-rc2-21-g07888c665b40
 #
diff --git a/kmod/src/acl.c b/kmod/src/acl.c
index 86d398ab..8e371fb2 100644
--- a/kmod/src/acl.c
+++ b/kmod/src/acl.c
@@ -265,7 +265,7 @@ int scoutfs_acl_set_xattr(struct dentry *dentry, const char *name, const void *v
 	struct posix_acl *acl = NULL;
 	int ret;
 
-	if (!inode_owner_or_capable(dentry->d_inode))
+	if (!inode_owner_or_capable(KC_VFS_INIT_NS dentry->d_inode))
 		return -EPERM;
 
 	if (!IS_POSIXACL(dentry->d_inode))
diff --git a/kmod/src/data.c b/kmod/src/data.c
index 64859706..49ab801d 100644
--- a/kmod/src/data.c
+++ b/kmod/src/data.c
@@ -1305,8 +1305,8 @@ int scoutfs_data_move_blocks(struct inode *from, u64 from_off,
 		goto out;
 	}
 
-	ret = inode_permission(from, MAY_WRITE) ?:
-	      inode_permission(to, MAY_WRITE);
+	ret = inode_permission(KC_VFS_INIT_NS from, MAY_WRITE) ?:
+	      inode_permission(KC_VFS_INIT_NS to, MAY_WRITE);
 	if (ret < 0)
 		goto out;
 
diff --git a/kmod/src/dir.c b/kmod/src/dir.c
index ca23d3a6..6634cbf4 100644
--- a/kmod/src/dir.c
+++ b/kmod/src/dir.c
@@ -703,8 +703,9 @@ out_unlock:
 	return inode;
 }
 
-static int scoutfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
-		       dev_t rdev)
+static int scoutfs_mknod(KC_VFS_NS_DEF
+			 struct inode *dir,
+			 struct dentry *dentry, umode_t mode, dev_t rdev)
 {
 	struct super_block *sb = dir->i_sb;
 	struct inode *inode = NULL;
@@ -773,15 +774,20 @@ out:
 }
 
 /* XXX hmm, do something with excl? */
-static int scoutfs_create(struct inode *dir, struct dentry *dentry,
-			  umode_t mode, bool excl)
+static int scoutfs_create(KC_VFS_NS_DEF
+			  struct inode *dir,
+			  struct dentry *dentry, umode_t mode, bool excl)
 {
-	return scoutfs_mknod(dir, dentry, mode | S_IFREG, 0);
+	return scoutfs_mknod(KC_VFS_NS
+			     dir, dentry, mode | S_IFREG, 0);
 }
 
-static int scoutfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+static int scoutfs_mkdir(KC_VFS_NS_DEF
+			 struct inode *dir,
+			 struct dentry *dentry, umode_t mode)
 {
-	return scoutfs_mknod(dir, dentry, mode | S_IFDIR, 0);
+	return scoutfs_mknod(KC_VFS_NS
+			     dir, dentry, mode | S_IFDIR, 0);
 }
 
 static int scoutfs_link(struct dentry *old_dentry,
@@ -1176,7 +1182,8 @@ static const char *scoutfs_get_link(struct dentry *dentry, struct inode *inode,
  * Symlink target paths can be annoyingly large.  We store relatively
  * rare large paths in multiple items.
  */
-static int scoutfs_symlink(struct inode *dir, struct dentry *dentry,
+static int scoutfs_symlink(KC_VFS_NS_DEF
+			   struct inode *dir, struct dentry *dentry,
 			   const char *symname)
 {
 	struct super_block *sb = dir->i_sb;
@@ -1563,7 +1570,8 @@ static int verify_ancestors(struct super_block *sb, u64 p1, u64 p2,
  * from using parent/child locking orders as two groups can have both
  * parent and child relationships to each other.
  */
-static int scoutfs_rename_common(struct inode *old_dir,
+static int scoutfs_rename_common(KC_VFS_NS_DEF
+				 struct inode *old_dir,
 				 struct dentry *old_dentry, struct inode *new_dir,
 				 struct dentry *new_dentry, unsigned int flags)
 {
@@ -1840,18 +1848,21 @@ static int scoutfs_rename(struct inode *old_dir,
 			  struct dentry *old_dentry, struct inode *new_dir,
 			  struct dentry *new_dentry)
 {
-	return scoutfs_rename_common(old_dir, old_dentry, new_dir, new_dentry, 0);
+	return scoutfs_rename_common(KC_VFS_INIT_NS
+				     old_dir, old_dentry, new_dir, new_dentry, 0);
 }
 #endif
 
-static int scoutfs_rename2(struct inode *old_dir,
+static int scoutfs_rename2(KC_VFS_NS_DEF
+			  struct inode *old_dir,
 			  struct dentry *old_dentry, struct inode *new_dir,
 			  struct dentry *new_dentry, unsigned int flags)
 {
 	if (flags & ~RENAME_NOREPLACE)
 		return -EINVAL;
 
-	return scoutfs_rename_common(old_dir, old_dentry, new_dir, new_dentry, flags);
+	return scoutfs_rename_common(KC_VFS_NS
+				     old_dir, old_dentry, new_dir, new_dentry, flags);
 }
 
 #ifdef KC_FMODE_KABI_ITERATE
@@ -1863,7 +1874,8 @@ static int scoutfs_dir_open(struct inode *inode, struct file *file)
 }
 #endif
 
-static int scoutfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
+static int scoutfs_tmpfile(KC_VFS_NS_DEF
+			   struct inode *dir, struct dentry *dentry, umode_t mode)
 {
 	struct super_block *sb = dir->i_sb;
 	struct inode *inode = NULL;
diff --git a/kmod/src/file.c b/kmod/src/file.c
index d44cd822..15158a2b 100644
--- a/kmod/src/file.c
+++ b/kmod/src/file.c
@@ -267,7 +267,8 @@ out:
 }
 #endif
 
-int scoutfs_permission(struct inode *inode, int mask)
+int scoutfs_permission(KC_VFS_NS_DEF
+		       struct inode *inode, int mask)
 {
 	struct super_block *sb = inode->i_sb;
 	struct scoutfs_lock *inode_lock = NULL;
@@ -281,7 +282,8 @@ int scoutfs_permission(struct inode *inode, int mask)
 	if (ret)
 		return ret;
 
-	ret = generic_permission(inode, mask);
+	ret = generic_permission(KC_VFS_INIT_NS
+				 inode, mask);
 
 	scoutfs_unlock(sb, inode_lock, SCOUTFS_LOCK_READ);
 
diff --git a/kmod/src/file.h b/kmod/src/file.h
index 82829ef5..1009b11f 100644
--- a/kmod/src/file.h
+++ b/kmod/src/file.h
@@ -10,7 +10,8 @@ ssize_t scoutfs_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 ssize_t scoutfs_file_read_iter(struct kiocb *, struct iov_iter *);
 ssize_t scoutfs_file_write_iter(struct kiocb *, struct iov_iter *);
 #endif
-int scoutfs_permission(struct inode *inode, int mask);
+int scoutfs_permission(KC_VFS_NS_DEF
+		       struct inode *inode, int mask);
 loff_t scoutfs_file_llseek(struct file *file, loff_t offset, int whence);
 
 #endif	/* _SCOUTFS_FILE_H_ */
diff --git a/kmod/src/inode.c b/kmod/src/inode.c
index 04c088c2..5e3f724f 100644
--- a/kmod/src/inode.c
+++ b/kmod/src/inode.c
@@ -373,7 +373,8 @@ int scoutfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 {
 	struct inode *inode = dentry->d_inode;
 #else
-int scoutfs_getattr(const struct path *path, struct kstat *stat,
+int scoutfs_getattr(KC_VFS_NS_DEF
+		    const struct path *path, struct kstat *stat,
 		    u32 request_mask, unsigned int query_flags)
 {
 	struct inode *inode = d_inode(path->dentry);
@@ -385,7 +386,8 @@ int scoutfs_getattr(const struct path *path, struct kstat *stat,
 	ret = scoutfs_lock_inode(sb, SCOUTFS_LOCK_READ,
 				 SCOUTFS_LKF_REFRESH_INODE, inode, &lock);
 	if (ret == 0) {
-		generic_fillattr(inode, stat);
+		generic_fillattr(KC_VFS_INIT_NS
+				 inode, stat);
 		scoutfs_unlock(sb, lock, SCOUTFS_LOCK_READ);
 	}
 	return ret;
@@ -483,7 +485,8 @@ int scoutfs_complete_truncate(struct inode *inode, struct scoutfs_lock *lock)
  * re-acquire it.  Ideally we'd fix this so that we can acquire the lock
  * instead of the caller.
  */
-int scoutfs_setattr(struct dentry *dentry, struct iattr *attr)
+int scoutfs_setattr(KC_VFS_NS_DEF
+		    struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = dentry->d_inode;
 	struct super_block *sb = inode->i_sb;
@@ -501,7 +504,8 @@ retry:
 				 SCOUTFS_LKF_REFRESH_INODE, inode, &lock);
 	if (ret)
 		return ret;
-	ret = setattr_prepare(dentry, attr);
+	ret = setattr_prepare(KC_VFS_INIT_NS
+			      dentry, attr);
 	if (ret)
 		goto out;
 
@@ -565,7 +569,8 @@ retry:
 	if (ret < 0)
 		goto release;
 
-	setattr_copy(inode, attr);
+	setattr_copy(KC_VFS_INIT_NS
+		     inode, attr);
 	inode_inc_iversion(inode);
 	scoutfs_update_inode_item(inode, lock, &ind_locks);
 
@@ -1562,7 +1567,8 @@ int scoutfs_new_inode(struct super_block *sb, struct inode *dir, umode_t mode, d
 	scoutfs_inode_set_data_seq(inode);
 
 	inode->i_ino = ino; /* XXX overflow */
-	inode_init_owner(inode, dir, mode);
+	inode_init_owner(KC_VFS_INIT_NS
+			 inode, dir, mode);
 	inode_set_bytes(inode, 0);
 	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
 	inode->i_rdev = rdev;
diff --git a/kmod/src/inode.h b/kmod/src/inode.h
index e068cee5..fcead8fb 100644
--- a/kmod/src/inode.h
+++ b/kmod/src/inode.h
@@ -135,10 +135,12 @@ int scoutfs_inode_refresh(struct inode *inode, struct scoutfs_lock *lock);
 int scoutfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 		    struct kstat *stat);
 #else
-int scoutfs_getattr(const struct path *path, struct kstat *stat,
+int scoutfs_getattr(KC_VFS_NS_DEF
+		    const struct path *path, struct kstat *stat,
 		    u32 request_mask, unsigned int query_flags);
 #endif
-int scoutfs_setattr(struct dentry *dentry, struct iattr *attr);
+int scoutfs_setattr(KC_VFS_NS_DEF
+		    struct dentry *dentry, struct iattr *attr);
 
 int scoutfs_inode_orphan_create(struct super_block *sb, u64 ino, struct scoutfs_lock *lock,
 				struct scoutfs_lock *primary);
diff --git a/kmod/src/ioctl.c b/kmod/src/ioctl.c
index 45fc0e51..9480d339 100644
--- a/kmod/src/ioctl.c
+++ b/kmod/src/ioctl.c
@@ -716,7 +716,8 @@ static long scoutfs_ioc_listxattr_hidden(struct file *file, unsigned long arg)
 	int total = 0;
 	int ret;
 
-	ret = inode_permission(inode, MAY_READ);
+	ret = inode_permission(KC_VFS_INIT_NS
+			       inode, MAY_READ);
 	if (ret < 0)
 		goto out;
 
diff --git a/kmod/src/kernelcompat.h b/kmod/src/kernelcompat.h
index 1d7acee7..247aa4e1 100644
--- a/kmod/src/kernelcompat.h
+++ b/kmod/src/kernelcompat.h
@@ -290,6 +290,16 @@ typedef unsigned int blk_opf_t;
 #define kc__vmalloc __vmalloc
 #endif
 
+#ifdef KC_VFS_METHOD_USER_NAMESPACE_ARG
+#define KC_VFS_NS_DEF struct user_namespace *mnt_user_ns,
+#define KC_VFS_NS mnt_user_ns,
+#define KC_VFS_INIT_NS &init_user_ns,
+#else
+#define KC_VFS_NS_DEF
+#define KC_VFS_NS
+#define KC_VFS_INIT_NS
+#endif
+
 #ifdef KC_BIO_ALLOC_DEV_OPF_ARGS
 #define kc_bio_alloc bio_alloc
 #else