fs: port inode_init_owner() to 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 <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

41 files changed, 124 insertions, 143 deletions

diff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c
index 19fec984fdb0..ea807aa0c31a 100644
--- a/arch/powerpc/platforms/cell/spufs/inode.c
+++ b/arch/powerpc/platforms/cell/spufs/inode.c
@@ -237,7 +237,7 @@ spufs_mkdir(struct inode *dir, struct dentry *dentry, unsigned int flags,
 	if (!inode)
 		return -ENOSPC;
 
-	inode_init_owner(&init_user_ns, inode, dir, mode | S_IFDIR);
+	inode_init_owner(&nop_mnt_idmap, inode, dir, mode | S_IFDIR);
 	ctx = alloc_spu_context(SPUFS_I(dir)->i_gang); /* XXX gang */
 	SPUFS_I(inode)->i_ctx = ctx;
 	if (!ctx) {
@@ -468,7 +468,7 @@ spufs_mkgang(struct inode *dir, struct dentry *dentry, umode_t mode)
 		goto out;
 
 	ret = 0;
-	inode_init_owner(&init_user_ns, inode, dir, mode | S_IFDIR);
+	inode_init_owner(&nop_mnt_idmap, inode, dir, mode | S_IFDIR);
 	gang = alloc_spu_gang();
 	SPUFS_I(inode)->i_ctx = NULL;
 	SPUFS_I(inode)->i_gang = gang;
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index a714df142d05..4344e7a7865f 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -260,7 +260,7 @@ int v9fs_init_inode(struct v9fs_session_info *v9ses,
 {
 	int err = 0;
 
-	inode_init_owner(&init_user_ns, inode, NULL, mode);
+	inode_init_owner(&nop_mnt_idmap, inode, NULL, mode);
 	inode->i_blocks = 0;
 	inode->i_rdev = rdev;
 	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
diff --git a/fs/bfs/dir.c b/fs/bfs/dir.c
index fa3e66bc9be3..040d5140e426 100644
--- a/fs/bfs/dir.c
+++ b/fs/bfs/dir.c
@@ -96,7 +96,7 @@ static int bfs_create(struct mnt_idmap *idmap, struct inode *dir,
 	}
 	set_bit(ino, info->si_imap);
 	info->si_freei--;
-	inode_init_owner(&init_user_ns, inode, dir, mode);
+	inode_init_owner(&nop_mnt_idmap, inode, dir, mode);
 	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
 	inode->i_blocks = 0;
 	inode->i_op = &bfs_file_inops;
diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index 195c09e20609..7c1527fcc7b3 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -469,7 +469,7 @@ int btrfs_new_inode_prepare(struct btrfs_new_inode_args *args,
 int btrfs_create_new_inode(struct btrfs_trans_handle *trans,
 			   struct btrfs_new_inode_args *args);
 void btrfs_new_inode_args_destroy(struct btrfs_new_inode_args *args);
-struct inode *btrfs_new_subvol_inode(struct user_namespace *mnt_userns,
+struct inode *btrfs_new_subvol_inode(struct mnt_idmap *idmap,
 				     struct inode *dir);
  void btrfs_set_delalloc_extent(struct btrfs_inode *inode, struct extent_state *state,
 			        u32 bits);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 5251547fdf0b..8d74d042c626 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6727,13 +6727,12 @@ out_inode:
 static int btrfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
 		       struct dentry *dentry, umode_t mode, dev_t rdev)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct inode *inode;
 
 	inode = new_inode(dir->i_sb);
 	if (!inode)
 		return -ENOMEM;
-	inode_init_owner(mnt_userns, inode, dir, mode);
+	inode_init_owner(idmap, inode, dir, mode);
 	inode->i_op = &btrfs_special_inode_operations;
 	init_special_inode(inode, inode->i_mode, rdev);
 	return btrfs_create_common(dir, dentry, inode);
@@ -6742,13 +6741,12 @@ static int btrfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
 static int btrfs_create(struct mnt_idmap *idmap, struct inode *dir,
 			struct dentry *dentry, umode_t mode, bool excl)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct inode *inode;
 
 	inode = new_inode(dir->i_sb);
 	if (!inode)
 		return -ENOMEM;
-	inode_init_owner(mnt_userns, inode, dir, mode);
+	inode_init_owner(idmap, inode, dir, mode);
 	inode->i_fop = &btrfs_file_operations;
 	inode->i_op = &btrfs_file_inode_operations;
 	inode->i_mapping->a_ops = &btrfs_aops;
@@ -6842,13 +6840,12 @@ fail:
 static int btrfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		       struct dentry *dentry, umode_t mode)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct inode *inode;
 
 	inode = new_inode(dir->i_sb);
 	if (!inode)
 		return -ENOMEM;
-	inode_init_owner(mnt_userns, inode, dir, S_IFDIR | mode);
+	inode_init_owner(idmap, inode, dir, S_IFDIR | mode);
 	inode->i_op = &btrfs_dir_inode_operations;
 	inode->i_fop = &btrfs_dir_file_operations;
 	return btrfs_create_common(dir, dentry, inode);
@@ -8805,7 +8802,7 @@ out:
 	return ret;
 }
 
-struct inode *btrfs_new_subvol_inode(struct user_namespace *mnt_userns,
+struct inode *btrfs_new_subvol_inode(struct mnt_idmap *idmap,
 				     struct inode *dir)
 {
 	struct inode *inode;
@@ -8816,7 +8813,7 @@ struct inode *btrfs_new_subvol_inode(struct user_namespace *mnt_userns,
 		 * Subvolumes don't inherit the sgid bit or the parent's gid if
 		 * the parent's sgid bit is set. This is probably a bug.
 		 */
-		inode_init_owner(mnt_userns, inode, NULL,
+		inode_init_owner(idmap, inode, NULL,
 				 S_IFDIR | (~current_umask() & S_IRWXUGO));
 		inode->i_op = &btrfs_dir_inode_operations;
 		inode->i_fop = &btrfs_dir_file_operations;
@@ -9292,14 +9289,14 @@ out_notrans:
 	return ret;
 }
 
-static struct inode *new_whiteout_inode(struct user_namespace *mnt_userns,
+static struct inode *new_whiteout_inode(struct mnt_idmap *idmap,
 					struct inode *dir)
 {
 	struct inode *inode;
 
 	inode = new_inode(dir->i_sb);
 	if (inode) {
-		inode_init_owner(mnt_userns, inode, dir,
+		inode_init_owner(idmap, inode, dir,
 				 S_IFCHR | WHITEOUT_MODE);
 		inode->i_op = &btrfs_special_inode_operations;
 		init_special_inode(inode, inode->i_mode, WHITEOUT_DEV);
@@ -9307,7 +9304,7 @@ static struct inode *new_whiteout_inode(struct user_namespace *mnt_userns,
 	return inode;
 }
 
-static int btrfs_rename(struct user_namespace *mnt_userns,
+static int btrfs_rename(struct mnt_idmap *idmap,
 			struct inode *old_dir, struct dentry *old_dentry,
 			struct inode *new_dir, struct dentry *new_dentry,
 			unsigned int flags)
@@ -9379,7 +9376,7 @@ static int btrfs_rename(struct user_namespace *mnt_userns,
 		filemap_flush(old_inode->i_mapping);
 
 	if (flags & RENAME_WHITEOUT) {
-		whiteout_args.inode = new_whiteout_inode(mnt_userns, old_dir);
+		whiteout_args.inode = new_whiteout_inode(idmap, old_dir);
 		if (!whiteout_args.inode)
 			return -ENOMEM;
 		ret = btrfs_new_inode_prepare(&whiteout_args, &trans_num_items);
@@ -9550,7 +9547,6 @@ static int btrfs_rename2(struct mnt_idmap *idmap, struct inode *old_dir,
 			 struct dentry *old_dentry, struct inode *new_dir,
 			 struct dentry *new_dentry, unsigned int flags)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	int ret;
 
 	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
@@ -9560,7 +9556,7 @@ static int btrfs_rename2(struct mnt_idmap *idmap, struct inode *old_dir,
 		ret = btrfs_rename_exchange(old_dir, old_dentry, new_dir,
 					    new_dentry);
 	else
-		ret = btrfs_rename(mnt_userns, old_dir, old_dentry, new_dir,
+		ret = btrfs_rename(idmap, old_dir, old_dentry, new_dir,
 				   new_dentry, flags);
 
 	btrfs_btree_balance_dirty(BTRFS_I(new_dir)->root->fs_info);
@@ -9763,7 +9759,6 @@ out:
 static int btrfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			 struct dentry *dentry, const char *symname)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
 	struct btrfs_trans_handle *trans;
 	struct btrfs_root *root = BTRFS_I(dir)->root;
@@ -9789,7 +9784,7 @@ static int btrfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 	inode = new_inode(dir->i_sb);
 	if (!inode)
 		return -ENOMEM;
-	inode_init_owner(mnt_userns, inode, dir, S_IFLNK | S_IRWXUGO);
+	inode_init_owner(idmap, inode, dir, S_IFLNK | S_IRWXUGO);
 	inode->i_op = &btrfs_symlink_inode_operations;
 	inode_nohighmem(inode);
 	inode->i_mapping->a_ops = &btrfs_aops;
@@ -10097,7 +10092,6 @@ static int btrfs_permission(struct mnt_idmap *idmap,
 static int btrfs_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
 			 struct file *file, umode_t mode)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
 	struct btrfs_trans_handle *trans;
 	struct btrfs_root *root = BTRFS_I(dir)->root;
@@ -10113,7 +10107,7 @@ static int btrfs_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
 	inode = new_inode(dir->i_sb);
 	if (!inode)
 		return -ENOMEM;
-	inode_init_owner(mnt_userns, inode, dir, mode);
+	inode_init_owner(idmap, inode, dir, mode);
 	inode->i_fop = &btrfs_file_operations;
 	inode->i_op = &btrfs_file_inode_operations;
 	inode->i_mapping->a_ops = &btrfs_aops;
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 80c7feb30770..7c6bb1ff41b3 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -578,7 +578,7 @@ static unsigned int create_subvol_num_items(struct btrfs_qgroup_inherit *inherit
 	return num_items;
 }
 
-static noinline int create_subvol(struct user_namespace *mnt_userns,
+static noinline int create_subvol(struct mnt_idmap *idmap,
 				  struct inode *dir, struct dentry *dentry,
 				  struct btrfs_qgroup_inherit *inherit)
 {
@@ -623,7 +623,7 @@ static noinline int create_subvol(struct user_namespace *mnt_userns,
 	if (ret < 0)
 		goto out_root_item;
 
-	new_inode_args.inode = btrfs_new_subvol_inode(mnt_userns, dir);
+	new_inode_args.inode = btrfs_new_subvol_inode(idmap, dir);
 	if (!new_inode_args.inode) {
 		ret = -ENOMEM;
 		goto out_anon_dev;
@@ -962,7 +962,6 @@ static noinline int btrfs_mksubvol(const struct path *parent,
 	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
 	struct dentry *dentry;
 	struct fscrypt_str name_str = FSTR_INIT((char *)name, namelen);
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	int error;
 
 	error = down_write_killable_nested(&dir->i_rwsem, I_MUTEX_PARENT);
@@ -995,7 +994,7 @@ static noinline int btrfs_mksubvol(const struct path *parent,
 	if (snap_src)
 		error = create_snapshot(snap_src, dir, dentry, readonly, inherit);
 	else
-		error = create_subvol(mnt_userns, dir, dentry, inherit);
+		error = create_subvol(idmap, dir, dentry, inherit);
 
 	if (!error)
 		fsnotify_mkdir(dir, dentry);
diff --git a/fs/btrfs/tests/btrfs-tests.c b/fs/btrfs/tests/btrfs-tests.c
index 181469fc0bb3..ca09cf9afce8 100644
--- a/fs/btrfs/tests/btrfs-tests.c
+++ b/fs/btrfs/tests/btrfs-tests.c
@@ -64,7 +64,7 @@ struct inode *btrfs_new_test_inode(void)
 	BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
 	BTRFS_I(inode)->location.objectid = BTRFS_FIRST_FREE_OBJECTID;
 	BTRFS_I(inode)->location.offset = 0;
-	inode_init_owner(&init_user_ns, inode, NULL, S_IFREG);
+	inode_init_owner(&nop_mnt_idmap, inode, NULL, S_IFREG);
 
 	return inode;
 }
diff --git a/fs/ext2/ialloc.c b/fs/ext2/ialloc.c
index 78b8686d9a4a..a4e1d7a9c544 100644
--- a/fs/ext2/ialloc.c
+++ b/fs/ext2/ialloc.c
@@ -545,7 +545,7 @@ got:
 		inode->i_uid = current_fsuid();
 		inode->i_gid = dir->i_gid;
 	} else
-		inode_init_owner(&init_user_ns, inode, dir, mode);
+		inode_init_owner(&nop_mnt_idmap, inode, dir, mode);
 
 	inode->i_ino = ino;
 	inode->i_blocks = 0;
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 8d5008754cc2..43e26e6f6e42 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2845,7 +2845,7 @@ extern int ext4fs_dirhash(const struct inode *dir, const char *name, int len,
 
 /* ialloc.c */
 extern int ext4_mark_inode_used(struct super_block *sb, int ino);
-extern struct inode *__ext4_new_inode(struct user_namespace *, handle_t *,
+extern struct inode *__ext4_new_inode(struct mnt_idmap *, handle_t *,
 				      struct inode *, umode_t,
 				      const struct qstr *qstr, __u32 goal,
 				      uid_t *owner, __u32 i_flags,
@@ -2853,11 +2853,11 @@ extern struct inode *__ext4_new_inode(struct user_namespace *, handle_t *,
 				      int nblocks);
 
 #define ext4_new_inode(handle, dir, mode, qstr, goal, owner, i_flags)          \
-	__ext4_new_inode(&init_user_ns, (handle), (dir), (mode), (qstr),       \
+	__ext4_new_inode(&nop_mnt_idmap, (handle), (dir), (mode), (qstr),      \
 			 (goal), (owner), i_flags, 0, 0, 0)
-#define ext4_new_inode_start_handle(mnt_userns, dir, mode, qstr, goal, owner, \
+#define ext4_new_inode_start_handle(idmap, dir, mode, qstr, goal, owner, \
 				    type, nblocks)		    \
-	__ext4_new_inode((mnt_userns), NULL, (dir), (mode), (qstr), (goal), (owner), \
+	__ext4_new_inode((idmap), NULL, (dir), (mode), (qstr), (goal), (owner), \
 			 0, (type), __LINE__, (nblocks))
 
 
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 63f9bb6e8851..1024b0c02431 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -921,7 +921,7 @@ static int ext4_xattr_credits_for_new_inode(struct inode *dir, mode_t mode,
  * For other inodes, search forward from the parent directory's block
  * group to find a free inode.
  */
-struct inode *__ext4_new_inode(struct user_namespace *mnt_userns,
+struct inode *__ext4_new_inode(struct mnt_idmap *idmap,
 			       handle_t *handle, struct inode *dir,
 			       umode_t mode, const struct qstr *qstr,
 			       __u32 goal, uid_t *owner, __u32 i_flags,
@@ -943,6 +943,7 @@ struct inode *__ext4_new_inode(struct user_namespace *mnt_userns,
 	ext4_group_t flex_group;
 	struct ext4_group_info *grp = NULL;
 	bool encrypt = false;
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 
 	/* Cannot create files in a deleted directory */
 	if (!dir || !dir->i_nlink)
@@ -975,7 +976,7 @@ struct inode *__ext4_new_inode(struct user_namespace *mnt_userns,
 		inode_fsuid_set(inode, mnt_userns);
 		inode->i_gid = dir->i_gid;
 	} else
-		inode_init_owner(mnt_userns, inode, dir, mode);
+		inode_init_owner(idmap, inode, dir, mode);
 
 	if (ext4_has_feature_project(sb) &&
 	    ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT))
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 74a2c3eae066..d10a508d95cd 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2795,7 +2795,6 @@ static int ext4_add_nondir(handle_t *handle,
 static int ext4_create(struct mnt_idmap *idmap, struct inode *dir,
 		       struct dentry *dentry, umode_t mode, bool excl)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	handle_t *handle;
 	struct inode *inode;
 	int err, credits, retries = 0;
@@ -2807,7 +2806,7 @@ static int ext4_create(struct mnt_idmap *idmap, struct inode *dir,
 	credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
 		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
 retry:
-	inode = ext4_new_inode_start_handle(mnt_userns, dir, mode, &dentry->d_name,
+	inode = ext4_new_inode_start_handle(idmap, dir, mode, &dentry->d_name,
 					    0, NULL, EXT4_HT_DIR, credits);
 	handle = ext4_journal_current_handle();
 	err = PTR_ERR(inode);
@@ -2831,7 +2830,6 @@ retry:
 static int ext4_mknod(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *dentry, umode_t mode, dev_t rdev)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	handle_t *handle;
 	struct inode *inode;
 	int err, credits, retries = 0;
@@ -2843,7 +2841,7 @@ static int ext4_mknod(struct mnt_idmap *idmap, struct inode *dir,
 	credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
 		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
 retry:
-	inode = ext4_new_inode_start_handle(mnt_userns, dir, mode, &dentry->d_name,
+	inode = ext4_new_inode_start_handle(idmap, dir, mode, &dentry->d_name,
 					    0, NULL, EXT4_HT_DIR, credits);
 	handle = ext4_journal_current_handle();
 	err = PTR_ERR(inode);
@@ -2866,7 +2864,6 @@ retry:
 static int ext4_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
 			struct file *file, umode_t mode)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	handle_t *handle;
 	struct inode *inode;
 	int err, retries = 0;
@@ -2876,7 +2873,7 @@ static int ext4_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
 		return err;
 
 retry:
-	inode = ext4_new_inode_start_handle(mnt_userns, dir, mode,
+	inode = ext4_new_inode_start_handle(idmap, dir, mode,
 					    NULL, 0, NULL,
 					    EXT4_HT_DIR,
 			EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
@@ -2978,7 +2975,6 @@ out:
 static int ext4_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *dentry, umode_t mode)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	handle_t *handle;
 	struct inode *inode;
 	int err, err2 = 0, credits, retries = 0;
@@ -2993,7 +2989,7 @@ static int ext4_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 	credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
 		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
 retry:
-	inode = ext4_new_inode_start_handle(mnt_userns, dir, S_IFDIR | mode,
+	inode = ext4_new_inode_start_handle(idmap, dir, S_IFDIR | mode,
 					    &dentry->d_name,
 					    0, NULL, EXT4_HT_DIR, credits);
 	handle = ext4_journal_current_handle();
@@ -3346,7 +3342,6 @@ out:
 static int ext4_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			struct dentry *dentry, const char *symname)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	handle_t *handle;
 	struct inode *inode;
 	int err, len = strlen(symname);
@@ -3375,7 +3370,7 @@ static int ext4_symlink(struct mnt_idmap *idmap, struct inode *dir,
 	credits = EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
 		  EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3;
 retry:
-	inode = ext4_new_inode_start_handle(mnt_userns, dir, S_IFLNK|S_IRWXUGO,
+	inode = ext4_new_inode_start_handle(idmap, dir, S_IFLNK|S_IRWXUGO,
 					    &dentry->d_name, 0, NULL,
 					    EXT4_HT_DIR, credits);
 	handle = ext4_journal_current_handle();
@@ -3725,7 +3720,7 @@ static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
 	}
 }
 
-static struct inode *ext4_whiteout_for_rename(struct user_namespace *mnt_userns,
+static struct inode *ext4_whiteout_for_rename(struct mnt_idmap *idmap,
 					      struct ext4_renament *ent,
 					      int credits, handle_t **h)
 {
@@ -3740,7 +3735,7 @@ static struct inode *ext4_whiteout_for_rename(struct user_namespace *mnt_userns,
 	credits += (EXT4_MAXQUOTAS_TRANS_BLOCKS(ent->dir->i_sb) +
 		    EXT4_XATTR_TRANS_BLOCKS + 4);
 retry:
-	wh = ext4_new_inode_start_handle(mnt_userns, ent->dir,
+	wh = ext4_new_inode_start_handle(idmap, ent->dir,
 					 S_IFCHR | WHITEOUT_MODE,
 					 &ent->dentry->d_name, 0, NULL,
 					 EXT4_HT_DIR, credits);
@@ -3768,7 +3763,7 @@ retry:
  * while new_{dentry,inode) refers to the destination dentry/inode
  * This comes from rename(const char *oldpath, const char *newpath)
  */
-static int ext4_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+static int ext4_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 		       struct dentry *old_dentry, struct inode *new_dir,
 		       struct dentry *new_dentry, unsigned int flags)
 {
@@ -3856,7 +3851,7 @@ static int ext4_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
 			goto release_bh;
 		}
 	} else {
-		whiteout = ext4_whiteout_for_rename(mnt_userns, &old, credits, &handle);
+		whiteout = ext4_whiteout_for_rename(idmap, &old, credits, &handle);
 		if (IS_ERR(whiteout)) {
 			retval = PTR_ERR(whiteout);
 			goto release_bh;
@@ -4168,7 +4163,6 @@ static int ext4_rename2(struct mnt_idmap *idmap,
 			struct inode *new_dir, struct dentry *new_dentry,
 			unsigned int flags)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	int err;
 
 	if (unlikely(ext4_forced_shutdown(EXT4_SB(old_dir->i_sb))))
@@ -4187,7 +4181,7 @@ static int ext4_rename2(struct mnt_idmap *idmap,
 					 new_dir, new_dentry);
 	}
 
-	return ext4_rename(mnt_userns, old_dir, old_dentry, new_dir, new_dentry, flags);
+	return ext4_rename(idmap, old_dir, old_dentry, new_dir, new_dentry, flags);
 }
 
 /*
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index cf0217d36402..9a3ffa39ad30 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3505,7 +3505,7 @@ void f2fs_handle_failed_inode(struct inode *inode);
 int f2fs_update_extension_list(struct f2fs_sb_info *sbi, const char *name,
 							bool hot, bool set);
 struct dentry *f2fs_get_parent(struct dentry *child);
-int f2fs_get_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
+int f2fs_get_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
 		     struct inode **new_inode);
 
 /*
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 96dd5cb2f49c..1d514515a6e7 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2040,7 +2040,8 @@ static int f2fs_ioc_getversion(struct file *filp, unsigned long arg)
 static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate)
 {
 	struct inode *inode = file_inode(filp);
-	struct user_namespace *mnt_userns = file_mnt_user_ns(filp);
+	struct mnt_idmap *idmap = file_mnt_idmap(filp);
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct f2fs_inode_info *fi = F2FS_I(inode);
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct inode *pinode;
@@ -2097,7 +2098,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate)
 		goto out;
 	}
 
-	ret = f2fs_get_tmpfile(mnt_userns, pinode, &fi->cow_inode);
+	ret = f2fs_get_tmpfile(idmap, pinode, &fi->cow_inode);
 	iput(pinode);
 	if (ret) {
 		f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 938032cbc1a8..d8e01bbbf27f 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -202,7 +202,7 @@ static void set_file_temperature(struct f2fs_sb_info *sbi, struct inode *inode,
 		file_set_hot(inode);
 }
 
-static struct inode *f2fs_new_inode(struct user_namespace *mnt_userns,
+static struct inode *f2fs_new_inode(struct mnt_idmap *idmap,
 						struct inode *dir, umode_t mode,
 						const char *name)
 {
@@ -225,7 +225,7 @@ static struct inode *f2fs_new_inode(struct user_namespace *mnt_userns,
 
 	nid_free = true;
 
-	inode_init_owner(mnt_userns, inode, dir, mode);
+	inode_init_owner(idmap, inode, dir, mode);
 
 	inode->i_ino = ino;
 	inode->i_blocks = 0;
@@ -336,7 +336,6 @@ fail_drop:
 static int f2fs_create(struct mnt_idmap *idmap, struct inode *dir,
 		       struct dentry *dentry, umode_t mode, bool excl)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
 	struct inode *inode;
 	nid_t ino = 0;
@@ -351,7 +350,7 @@ static int f2fs_create(struct mnt_idmap *idmap, struct inode *dir,
 	if (err)
 		return err;
 
-	inode = f2fs_new_inode(mnt_userns, dir, mode, dentry->d_name.name);
+	inode = f2fs_new_inode(idmap, dir, mode, dentry->d_name.name);
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
 
@@ -663,7 +662,6 @@ static const char *f2fs_get_link(struct dentry *dentry,
 static int f2fs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			struct dentry *dentry, const char *symname)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
 	struct inode *inode;
 	size_t len = strlen(symname);
@@ -684,7 +682,7 @@ static int f2fs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 	if (err)
 		return err;
 
-	inode = f2fs_new_inode(mnt_userns, dir, S_IFLNK | S_IRWXUGO, NULL);
+	inode = f2fs_new_inode(idmap, dir, S_IFLNK | S_IRWXUGO, NULL);
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
 
@@ -744,7 +742,6 @@ out_free_encrypted_link:
 static int f2fs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *dentry, umode_t mode)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
 	struct inode *inode;
 	int err;
@@ -756,7 +753,7 @@ static int f2fs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 	if (err)
 		return err;
 
-	inode = f2fs_new_inode(mnt_userns, dir, S_IFDIR | mode, NULL);
+	inode = f2fs_new_inode(idmap, dir, S_IFDIR | mode, NULL);
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
 
@@ -800,7 +797,6 @@ static int f2fs_rmdir(struct inode *dir, struct dentry *dentry)
 static int f2fs_mknod(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *dentry, umode_t mode, dev_t rdev)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
 	struct inode *inode;
 	int err = 0;
@@ -814,7 +810,7 @@ static int f2fs_mknod(struct mnt_idmap *idmap, struct inode *dir,
 	if (err)
 		return err;
 
-	inode = f2fs_new_inode(mnt_userns, dir, mode, NULL);
+	inode = f2fs_new_inode(idmap, dir, mode, NULL);
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
 
@@ -841,7 +837,7 @@ out:
 	return err;
 }
 
-static int __f2fs_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
+static int __f2fs_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
 			  struct file *file, umode_t mode, bool is_whiteout,
 			  struct inode **new_inode)
 {
@@ -853,7 +849,7 @@ static int __f2fs_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
 	if (err)
 		return err;
 
-	inode = f2fs_new_inode(mnt_userns, dir, mode, NULL);
+	inode = f2fs_new_inode(idmap, dir, mode, NULL);
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
 
@@ -914,7 +910,6 @@ out:
 static int f2fs_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
 			struct file *file, umode_t mode)