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>

6 files changed, 36 insertions, 39 deletions

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index d354ea2b74f9..f6e27224bd59 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -777,7 +777,7 @@ xfs_inode_inherit_flags2(
  */
 int
 xfs_init_new_inode(
-	struct user_namespace	*mnt_userns,
+	struct mnt_idmap	*idmap,
 	struct xfs_trans	*tp,
 	struct xfs_inode	*pip,
 	xfs_ino_t		ino,
@@ -788,6 +788,7 @@ xfs_init_new_inode(
 	bool			init_xattrs,
 	struct xfs_inode	**ipp)
 {
+	struct user_namespace	*mnt_userns = mnt_idmap_owner(idmap);
 	struct inode		*dir = pip ? VFS_I(pip) : NULL;
 	struct xfs_mount	*mp = tp->t_mountp;
 	struct xfs_inode	*ip;
@@ -827,7 +828,7 @@ xfs_init_new_inode(
 		inode->i_gid = dir->i_gid;
 		inode->i_mode = mode;
 	} else {
-		inode_init_owner(mnt_userns, inode, dir, mode);
+		inode_init_owner(idmap, inode, dir, mode);
 	}
 
 	/*
@@ -946,7 +947,7 @@ xfs_bumplink(
 
 int
 xfs_create(
-	struct user_namespace	*mnt_userns,
+	struct mnt_idmap	*idmap,
 	xfs_inode_t		*dp,
 	struct xfs_name		*name,
 	umode_t			mode,
@@ -954,6 +955,7 @@ xfs_create(
 	bool			init_xattrs,
 	xfs_inode_t		**ipp)
 {
+	struct user_namespace	*mnt_userns = mnt_idmap_owner(idmap);
 	int			is_dir = S_ISDIR(mode);
 	struct xfs_mount	*mp = dp->i_mount;
 	struct xfs_inode	*ip = NULL;
@@ -1020,7 +1022,7 @@ xfs_create(
 	 */
 	error = xfs_dialloc(&tp, dp->i_ino, mode, &ino);
 	if (!error)
-		error = xfs_init_new_inode(mnt_userns, tp, dp, ino, mode,
+		error = xfs_init_new_inode(idmap, tp, dp, ino, mode,
 				is_dir ? 2 : 1, rdev, prid, init_xattrs, &ip);
 	if (error)
 		goto out_trans_cancel;
@@ -1102,11 +1104,12 @@ xfs_create(
 
 int
 xfs_create_tmpfile(
-	struct user_namespace	*mnt_userns,
+	struct mnt_idmap	*idmap,
 	struct xfs_inode	*dp,
 	umode_t			mode,
 	struct xfs_inode	**ipp)
 {
+	struct user_namespace	*mnt_userns = mnt_idmap_owner(idmap);
 	struct xfs_mount	*mp = dp->i_mount;
 	struct xfs_inode	*ip = NULL;
 	struct xfs_trans	*tp = NULL;
@@ -1144,7 +1147,7 @@ xfs_create_tmpfile(
 
 	error = xfs_dialloc(&tp, dp->i_ino, mode, &ino);
 	if (!error)
-		error = xfs_init_new_inode(mnt_userns, tp, dp, ino, mode,
+		error = xfs_init_new_inode(idmap, tp, dp, ino, mode,
 				0, 0, prid, false, &ip);
 	if (error)
 		goto out_trans_cancel;
@@ -2709,7 +2712,7 @@ out_trans_abort:
  */
 static int
 xfs_rename_alloc_whiteout(
-	struct user_namespace	*mnt_userns,
+	struct mnt_idmap	*idmap,
 	struct xfs_name		*src_name,
 	struct xfs_inode	*dp,
 	struct xfs_inode	**wip)
@@ -2718,7 +2721,7 @@ xfs_rename_alloc_whiteout(
 	struct qstr		name;
 	int			error;
 
-	error = xfs_create_tmpfile(mnt_userns, dp, S_IFCHR | WHITEOUT_MODE,
+	error = xfs_create_tmpfile(idmap, dp, S_IFCHR | WHITEOUT_MODE,
 				   &tmpfile);
 	if (error)
 		return error;
@@ -2750,7 +2753,7 @@ xfs_rename_alloc_whiteout(
  */
 int
 xfs_rename(
-	struct user_namespace	*mnt_userns,
+	struct mnt_idmap	*idmap,
 	struct xfs_inode	*src_dp,
 	struct xfs_name		*src_name,
 	struct xfs_inode	*src_ip,
@@ -2782,7 +2785,7 @@ xfs_rename(
 	 * appropriately.
 	 */
 	if (flags & RENAME_WHITEOUT) {
-		error = xfs_rename_alloc_whiteout(mnt_userns, src_name,
+		error = xfs_rename_alloc_whiteout(idmap, src_name,
 						  target_dp, &wip);
 		if (error)
 			return error;
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index fa780f08dc89..69d21e42c10a 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -473,18 +473,18 @@ int		xfs_release(struct xfs_inode *ip);
 void		xfs_inactive(struct xfs_inode *ip);
 int		xfs_lookup(struct xfs_inode *dp, const struct xfs_name *name,
 			   struct xfs_inode **ipp, struct xfs_name *ci_name);
-int		xfs_create(struct user_namespace *mnt_userns,
+int		xfs_create(struct mnt_idmap *idmap,
 			   struct xfs_inode *dp, struct xfs_name *name,
 			   umode_t mode, dev_t rdev, bool need_xattr,
 			   struct xfs_inode **ipp);
-int		xfs_create_tmpfile(struct user_namespace *mnt_userns,
+int		xfs_create_tmpfile(struct mnt_idmap *idmap,
 			   struct xfs_inode *dp, umode_t mode,
 			   struct xfs_inode **ipp);
 int		xfs_remove(struct xfs_inode *dp, struct xfs_name *name,
 			   struct xfs_inode *ip);
 int		xfs_link(struct xfs_inode *tdp, struct xfs_inode *sip,
 			 struct xfs_name *target_name);
-int		xfs_rename(struct user_namespace *mnt_userns,
+int		xfs_rename(struct mnt_idmap *idmap,
 			   struct xfs_inode *src_dp, struct xfs_name *src_name,
 			   struct xfs_inode *src_ip, struct xfs_inode *target_dp,
 			   struct xfs_name *target_name,
@@ -515,7 +515,7 @@ void		xfs_lock_two_inodes(struct xfs_inode *ip0, uint ip0_mode,
 xfs_extlen_t	xfs_get_extsz_hint(struct xfs_inode *ip);
 xfs_extlen_t	xfs_get_cowextsz_hint(struct xfs_inode *ip);
 
-int xfs_init_new_inode(struct user_namespace *mnt_userns, struct xfs_trans *tp,
+int xfs_init_new_inode(struct mnt_idmap *idmap, struct xfs_trans *tp,
 		struct xfs_inode *pip, xfs_ino_t ino, umode_t mode,
 		xfs_nlink_t nlink, dev_t rdev, prid_t prid, bool init_xattrs,
 		struct xfs_inode **ipp);
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 1323ac546e5f..94c2f4aa675a 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -162,12 +162,12 @@ xfs_create_need_xattr(
 
 STATIC int
 xfs_generic_create(
-	struct user_namespace	*mnt_userns,
-	struct inode	*dir,
-	struct dentry	*dentry,
-	umode_t		mode,
-	dev_t		rdev,
-	struct file	*tmpfile)	/* unnamed file */
+	struct mnt_idmap	*idmap,
+	struct inode		*dir,
+	struct dentry		*dentry,
+	umode_t			mode,
+	dev_t			rdev,
+	struct file		*tmpfile)	/* unnamed file */
 {
 	struct inode	*inode;
 	struct xfs_inode *ip = NULL;
@@ -196,11 +196,11 @@ xfs_generic_create(
 		goto out_free_acl;
 
 	if (!tmpfile) {
-		error = xfs_create(mnt_userns, XFS_I(dir), &name, mode, rdev,
+		error = xfs_create(idmap, XFS_I(dir), &name, mode, rdev,
 				xfs_create_need_xattr(dir, default_acl, acl),
 				&ip);
 	} else {
-		error = xfs_create_tmpfile(mnt_userns, XFS_I(dir), mode, &ip);
+		error = xfs_create_tmpfile(idmap, XFS_I(dir), mode, &ip);
 	}
 	if (unlikely(error))
 		goto out_free_acl;
@@ -261,8 +261,7 @@ xfs_vn_mknod(
 	umode_t			mode,
 	dev_t			rdev)
 {
-	return xfs_generic_create(mnt_idmap_owner(idmap), dir, dentry, mode,
-				  rdev, NULL);
+	return xfs_generic_create(idmap, dir, dentry, mode, rdev, NULL);
 }
 
 STATIC int
@@ -273,8 +272,7 @@ xfs_vn_create(
 	umode_t			mode,
 	bool			flags)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
-	return xfs_generic_create(mnt_userns, dir, dentry, mode, 0, NULL);
+	return xfs_generic_create(idmap, dir, dentry, mode, 0, NULL);
 }
 
 STATIC int
@@ -284,8 +282,7 @@ xfs_vn_mkdir(
 	struct dentry		*dentry,
 	umode_t			mode)
 {
-	return xfs_generic_create(mnt_idmap_owner(idmap), dir, dentry,
-				  mode | S_IFDIR, 0, NULL);
+	return xfs_generic_create(idmap, dir, dentry, mode | S_IFDIR, 0, NULL);
 }
 
 STATIC struct dentry *
@@ -407,7 +404,6 @@ xfs_vn_symlink(
 	struct dentry		*dentry,
 	const char		*symname)
 {
-	struct user_namespace	*mnt_userns = mnt_idmap_owner(idmap);
 	struct inode	*inode;
 	struct xfs_inode *cip = NULL;
 	struct xfs_name	name;
@@ -420,7 +416,7 @@ xfs_vn_symlink(
 	if (unlikely(error))
 		goto out;
 
-	error = xfs_symlink(mnt_userns, XFS_I(dir), &name, symname, mode, &cip);
+	error = xfs_symlink(idmap, XFS_I(dir), &name, symname, mode, &cip);
 	if (unlikely(error))
 		goto out;
 
@@ -453,7 +449,6 @@ xfs_vn_rename(
 	struct dentry		*ndentry,
 	unsigned int		flags)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 	struct inode	*new_inode = d_inode(ndentry);
 	int		omode = 0;
 	int		error;
@@ -476,7 +471,7 @@ xfs_vn_rename(
 	if (unlikely(error))
 		return error;
 
-	return xfs_rename(mnt_userns, XFS_I(odir), &oname,
+	return xfs_rename(idmap, XFS_I(odir), &oname,
 			  XFS_I(d_inode(odentry)), XFS_I(ndir), &nname,
 			  new_inode ? XFS_I(new_inode) : NULL, flags);
 }
@@ -1103,9 +1098,7 @@ xfs_vn_tmpfile(
 	struct file		*file,
 	umode_t			mode)
 {
-	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
-
-	int err = xfs_generic_create(mnt_userns, dir, file->f_path.dentry, mode, 0, file);
+	int err = xfs_generic_create(idmap, dir, file->f_path.dentry, mode, 0, file);
 
 	return finish_open_simple(file, err);
 }
diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
index ff53d40a2dae..a7303a9aa405 100644
--- a/fs/xfs/xfs_qm.c
+++ b/fs/xfs/xfs_qm.c
@@ -787,7 +787,7 @@ xfs_qm_qino_alloc(
 
 		error = xfs_dialloc(&tp, 0, S_IFREG, &ino);
 		if (!error)
-			error = xfs_init_new_inode(&init_user_ns, tp, NULL, ino,
+			error = xfs_init_new_inode(&nop_mnt_idmap, tp, NULL, ino,
 					S_IFREG, 1, 0, 0, false, ipp);
 		if (error) {
 			xfs_trans_cancel(tp);
diff --git a/fs/xfs/xfs_symlink.c b/fs/xfs/xfs_symlink.c
index 8389f3ef88ef..24cf0a16bf35 100644
--- a/fs/xfs/xfs_symlink.c
+++ b/fs/xfs/xfs_symlink.c
@@ -144,13 +144,14 @@ xfs_readlink(
 
 int
 xfs_symlink(
-	struct user_namespace	*mnt_userns,
+	struct mnt_idmap	*idmap,
 	struct xfs_inode	*dp,
 	struct xfs_name		*link_name,
 	const char		*target_path,
 	umode_t			mode,
 	struct xfs_inode	**ipp)
 {
+	struct user_namespace	*mnt_userns = mnt_idmap_owner(idmap);
 	struct xfs_mount	*mp = dp->i_mount;
 	struct xfs_trans	*tp = NULL;
 	struct xfs_inode	*ip = NULL;
@@ -231,7 +232,7 @@ xfs_symlink(
 	 */
 	error = xfs_dialloc(&tp, dp->i_ino, S_IFLNK, &ino);
 	if (!error)
-		error = xfs_init_new_inode(mnt_userns, tp, dp, ino,
+		error = xfs_init_new_inode(idmap, tp, dp, ino,
 				S_IFLNK | (mode & ~S_IFMT), 1, 0, prid,
 				false, &ip);
 	if (error)
diff --git a/fs/xfs/xfs_symlink.h b/fs/xfs/xfs_symlink.h
index 2586b7e393f3..d1ca1ce62a93 100644
--- a/fs/xfs/xfs_symlink.h
+++ b/fs/xfs/xfs_symlink.h
@@ -7,7 +7,7 @@
 
 /* Kernel only symlink definitions */
 
-int xfs_symlink(struct user_namespace *mnt_userns, struct xfs_inode *dp,
+int xfs_symlink(struct mnt_idmap *idmap, struct xfs_inode *dp,
 		struct xfs_name *link_name, const char *target_path,
 		umode_t mode, struct xfs_inode **ipp);
 int xfs_readlink_bmap_ilocked(struct xfs_inode *ip, char *link);