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

4 files changed, 21 insertions, 18 deletions

diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
index ba8146f39adb..50d049bb84de 100644
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -2512,6 +2512,7 @@ int smb2_open(struct ksmbd_work *work)
 	struct ksmbd_share_config *share = tcon->share_conf;
 	struct ksmbd_file *fp = NULL;
 	struct file *filp = NULL;
+	struct mnt_idmap *idmap = NULL;
 	struct user_namespace *user_ns = NULL;
 	struct kstat stat;
 	struct create_context *context;
@@ -2765,7 +2766,8 @@ int smb2_open(struct ksmbd_work *work)
 		rc = 0;
 	} else {
 		file_present = true;
-		user_ns = mnt_user_ns(path.mnt);
+		idmap = mnt_idmap(path.mnt);
+		user_ns = mnt_idmap_owner(idmap);
 	}
 	if (stream_name) {
 		if (req->CreateOptions & FILE_DIRECTORY_FILE_LE) {
@@ -2864,7 +2866,8 @@ int smb2_open(struct ksmbd_work *work)
 		}
 
 		created = true;
-		user_ns = mnt_user_ns(path.mnt);
+		idmap = mnt_idmap(path.mnt);
+		user_ns = mnt_idmap_owner(idmap);
 		if (ea_buf) {
 			if (le32_to_cpu(ea_buf->ccontext.DataLength) <
 			    sizeof(struct smb2_ea_info)) {
@@ -2957,7 +2960,7 @@ int smb2_open(struct ksmbd_work *work)
 		int posix_acl_rc;
 		struct inode *inode = d_inode(path.dentry);
 
-		posix_acl_rc = ksmbd_vfs_inherit_posix_acl(user_ns,
+		posix_acl_rc = ksmbd_vfs_inherit_posix_acl(idmap,
 							   path.dentry,
 							   d_inode(path.dentry->d_parent));
 		if (posix_acl_rc)
@@ -2973,7 +2976,7 @@ int smb2_open(struct ksmbd_work *work)
 			rc = smb2_create_sd_buffer(work, req, &path);
 			if (rc) {
 				if (posix_acl_rc)
-					ksmbd_vfs_set_init_posix_acl(user_ns,
+					ksmbd_vfs_set_init_posix_acl(idmap,
 								     path.dentry);
 
 				if (test_share_config_flag(work->tcon->share_conf,
diff --git a/fs/ksmbd/smbacl.c b/fs/ksmbd/smbacl.c
index 6490342bbb38..6e144880eeff 100644
--- a/fs/ksmbd/smbacl.c
+++ b/fs/ksmbd/smbacl.c
@@ -1384,17 +1384,17 @@ int set_info_sec(struct ksmbd_conn *conn, struct ksmbd_tree_connect *tcon,
 	newattrs.ia_valid |= ATTR_MODE;
 	newattrs.ia_mode = (inode->i_mode & ~0777) | (fattr.cf_mode & 0777);
 
-	ksmbd_vfs_remove_acl_xattrs(user_ns, path->dentry);
+	ksmbd_vfs_remove_acl_xattrs(idmap, path->dentry);
 	/* Update posix acls */
 	if (IS_ENABLED(CONFIG_FS_POSIX_ACL) && fattr.cf_dacls) {
-		rc = set_posix_acl(user_ns, path->dentry,
+		rc = set_posix_acl(idmap, path->dentry,
 				   ACL_TYPE_ACCESS, fattr.cf_acls);
 		if (rc < 0)
 			ksmbd_debug(SMB,
 				    "Set posix acl(ACL_TYPE_ACCESS) failed, rc : %d\n",
 				    rc);
 		if (S_ISDIR(inode->i_mode) && fattr.cf_dacls) {
-			rc = set_posix_acl(user_ns, path->dentry,
+			rc = set_posix_acl(idmap, path->dentry,
 					   ACL_TYPE_DEFAULT, fattr.cf_dacls);
 			if (rc)
 				ksmbd_debug(SMB,
diff --git a/fs/ksmbd/vfs.c b/fs/ksmbd/vfs.c
index cf60e62d6e73..21f420d21b3e 100644
--- a/fs/ksmbd/vfs.c
+++ b/fs/ksmbd/vfs.c
@@ -1305,7 +1305,7 @@ struct dentry *ksmbd_vfs_kern_path_create(struct ksmbd_work *work,
 	return dent;
 }
 
-int ksmbd_vfs_remove_acl_xattrs(struct user_namespace *user_ns,
+int ksmbd_vfs_remove_acl_xattrs(struct mnt_idmap *idmap,
 				struct dentry *dentry)
 {
 	char *name, *xattr_list = NULL;
@@ -1328,7 +1328,7 @@ int ksmbd_vfs_remove_acl_xattrs(struct user_namespace *user_ns,
 			     sizeof(XATTR_NAME_POSIX_ACL_ACCESS) - 1) ||
 		    !strncmp(name, XATTR_NAME_POSIX_ACL_DEFAULT,
 			     sizeof(XATTR_NAME_POSIX_ACL_DEFAULT) - 1)) {
-			err = vfs_remove_acl(user_ns, dentry, name);
+			err = vfs_remove_acl(idmap, dentry, name);
 			if (err)
 				ksmbd_debug(SMB,
 					    "remove acl xattr failed : %s\n", name);
@@ -1830,7 +1830,7 @@ void ksmbd_vfs_posix_lock_unblock(struct file_lock *flock)
 	locks_delete_block(flock);
 }
 
-int ksmbd_vfs_set_init_posix_acl(struct user_namespace *user_ns,
+int ksmbd_vfs_set_init_posix_acl(struct mnt_idmap *idmap,
 				 struct dentry *dentry)
 {
 	struct posix_acl_state acl_state;
@@ -1864,13 +1864,13 @@ int ksmbd_vfs_set_init_posix_acl(struct user_namespace *user_ns,
 		return -ENOMEM;
 	}
 	posix_state_to_acl(&acl_state, acls->a_entries);
-	rc = set_posix_acl(user_ns, dentry, ACL_TYPE_ACCESS, acls);
+	rc = set_posix_acl(idmap, dentry, ACL_TYPE_ACCESS, acls);
 	if (rc < 0)
 		ksmbd_debug(SMB, "Set posix acl(ACL_TYPE_ACCESS) failed, rc : %d\n",
 			    rc);
 	else if (S_ISDIR(inode->i_mode)) {
 		posix_state_to_acl(&acl_state, acls->a_entries);
-		rc = set_posix_acl(user_ns, dentry, ACL_TYPE_DEFAULT, acls);
+		rc = set_posix_acl(idmap, dentry, ACL_TYPE_DEFAULT, acls);
 		if (rc < 0)
 			ksmbd_debug(SMB, "Set posix acl(ACL_TYPE_DEFAULT) failed, rc : %d\n",
 				    rc);
@@ -1880,7 +1880,7 @@ int ksmbd_vfs_set_init_posix_acl(struct user_namespace *user_ns,
 	return rc;
 }
 
-int ksmbd_vfs_inherit_posix_acl(struct user_namespace *user_ns,
+int ksmbd_vfs_inherit_posix_acl(struct mnt_idmap *idmap,
 				struct dentry *dentry, struct inode *parent_inode)
 {
 	struct posix_acl *acls;
@@ -1903,12 +1903,12 @@ int ksmbd_vfs_inherit_posix_acl(struct user_namespace *user_ns,
 		}
 	}
 
-	rc = set_posix_acl(user_ns, dentry, ACL_TYPE_ACCESS, acls);
+	rc = set_posix_acl(idmap, dentry, ACL_TYPE_ACCESS, acls);
 	if (rc < 0)
 		ksmbd_debug(SMB, "Set posix acl(ACL_TYPE_ACCESS) failed, rc : %d\n",
 			    rc);
 	if (S_ISDIR(inode->i_mode)) {
-		rc = set_posix_acl(user_ns, dentry, ACL_TYPE_DEFAULT,
+		rc = set_posix_acl(idmap, dentry, ACL_TYPE_DEFAULT,
 				   acls);
 		if (rc < 0)
 			ksmbd_debug(SMB, "Set posix acl(ACL_TYPE_DEFAULT) failed, rc : %d\n",
diff --git a/fs/ksmbd/vfs.h b/fs/ksmbd/vfs.h
index 619304b08a7f..1f8c5ac03041 100644
--- a/fs/ksmbd/vfs.h
+++ b/fs/ksmbd/vfs.h
@@ -141,7 +141,7 @@ int ksmbd_vfs_fill_dentry_attrs(struct ksmbd_work *work,
 void ksmbd_vfs_posix_lock_wait(struct file_lock *flock);
 int ksmbd_vfs_posix_lock_wait_timeout(struct file_lock *flock, long timeout);
 void ksmbd_vfs_posix_lock_unblock(struct file_lock *flock);
-int ksmbd_vfs_remove_acl_xattrs(struct user_namespace *user_ns,
+int ksmbd_vfs_remove_acl_xattrs(struct mnt_idmap *idmap,
 				struct dentry *dentry);
 int ksmbd_vfs_remove_sd_xattrs(struct user_namespace *user_ns,
 			       struct dentry *dentry);
@@ -159,9 +159,9 @@ int ksmbd_vfs_set_dos_attrib_xattr(struct user_namespace *user_ns,
 int ksmbd_vfs_get_dos_attrib_xattr(struct user_namespace *user_ns,
 				   struct dentry *dentry,
 				   struct xattr_dos_attrib *da);
-int ksmbd_vfs_set_init_posix_acl(struct user_namespace *user_ns,
+int ksmbd_vfs_set_init_posix_acl(struct mnt_idmap *idmap,
 				 struct dentry *dentry);
-int ksmbd_vfs_inherit_posix_acl(struct user_namespace *user_ns,
+int ksmbd_vfs_inherit_posix_acl(struct mnt_idmap *idmap,
 				struct dentry *dentry,
 				struct inode *parent_inode);
 #endif /* __KSMBD_VFS_H__ */