fs: make helpers idmap mount aware

Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has been marked with. This can be used for
additional permission checking and also to enable filesystems to
translate between uids and gids if they need to. We have implemented all
relevant helpers in earlier patches.

As requested we simply extend the exisiting inode method instead of
introducing new ones. This is a little more code churn but it's mostly
mechanical and doesnt't leave us with additional inode methods.

Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

4 files changed, 11 insertions, 6 deletions

diff --git a/fs/configfs/configfs_internal.h b/fs/configfs/configfs_internal.h
index 22dce2d35a4b..9a3aed249692 100644
--- a/fs/configfs/configfs_internal.h
+++ b/fs/configfs/configfs_internal.h
@@ -79,7 +79,8 @@ extern void configfs_hash_and_remove(struct dentry * dir, const char * name);
 
 extern const unsigned char * configfs_get_name(struct configfs_dirent *sd);
 extern void configfs_drop_dentry(struct configfs_dirent *sd, struct dentry *parent);
-extern int configfs_setattr(struct dentry *dentry, struct iattr *iattr);
+extern int configfs_setattr(struct user_namespace *mnt_userns,
+			    struct dentry *dentry, struct iattr *iattr);
 
 extern struct dentry *configfs_pin_fs(void);
 extern void configfs_release_fs(void);
@@ -92,7 +93,8 @@ extern const struct inode_operations configfs_root_inode_operations;
 extern const struct inode_operations configfs_symlink_inode_operations;
 extern const struct dentry_operations configfs_dentry_ops;
 
-extern int configfs_symlink(struct inode *dir, struct dentry *dentry,
+extern int configfs_symlink(struct user_namespace *mnt_userns,
+			    struct inode *dir, struct dentry *dentry,
 			    const char *symname);
 extern int configfs_unlink(struct inode *dir, struct dentry *dentry);
 
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index b839dd1b459f..b6098e02e20b 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -1268,7 +1268,8 @@ out_root_unlock:
 }
 EXPORT_SYMBOL(configfs_depend_item_unlocked);
 
-static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+static int configfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+			  struct dentry *dentry, umode_t mode)
 {
 	int ret = 0;
 	int module_got = 0;
diff --git a/fs/configfs/inode.c b/fs/configfs/inode.c
index 8bd6a883c94c..42c348bb2903 100644
--- a/fs/configfs/inode.c
+++ b/fs/configfs/inode.c
@@ -40,7 +40,8 @@ static const struct inode_operations configfs_inode_operations ={
 	.setattr	= configfs_setattr,
 };
 
-int configfs_setattr(struct dentry * dentry, struct iattr * iattr)
+int configfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+		     struct iattr *iattr)
 {
 	struct inode * inode = d_inode(dentry);
 	struct configfs_dirent * sd = dentry->d_fsdata;
@@ -67,7 +68,7 @@ int configfs_setattr(struct dentry * dentry, struct iattr * iattr)
 	}
 	/* attributes were changed atleast once in past */
 
-	error = simple_setattr(dentry, iattr);
+	error = simple_setattr(mnt_userns, dentry, iattr);
 	if (error)
 		return error;
 
diff --git a/fs/configfs/symlink.c b/fs/configfs/symlink.c
index 8ca36394fa30..77c854364e60 100644
--- a/fs/configfs/symlink.c
+++ b/fs/configfs/symlink.c
@@ -139,7 +139,8 @@ static int get_target(const char *symname, struct path *path,
 }
 
 
-int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
+int configfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+		     struct dentry *dentry, const char *symname)
 {
 	int ret;
 	struct path path;