fs: port ->fileattr_set() 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>

1 files changed, 8 insertions, 8 deletions

diff --git a/fs/ioctl.c b/fs/ioctl.c
index 80ac36aea913..2bf1bdaec2ee 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -651,7 +651,7 @@ static int fileattr_set_prepare(struct inode *inode,
 
 /**
  * vfs_fileattr_set - change miscellaneous file attributes
- * @mnt_userns:	user namespace of the mount
+ * @idmap:	idmap of the mount
  * @dentry:	the object to change
  * @fa:		fileattr pointer
  *
@@ -665,7 +665,7 @@ static int fileattr_set_prepare(struct inode *inode,
  *
  * Return: 0 on success, or a negative error on failure.
  */
-int vfs_fileattr_set(struct user_namespace *mnt_userns, struct dentry *dentry,
+int vfs_fileattr_set(struct mnt_idmap *idmap, struct dentry *dentry,
 		     struct fileattr *fa)
 {
 	struct inode *inode = d_inode(dentry);
@@ -675,7 +675,7 @@ int vfs_fileattr_set(struct user_namespace *mnt_userns, struct dentry *dentry,
 	if (!inode->i_op->fileattr_set)
 		return -ENOIOCTLCMD;
 
-	if (!inode_owner_or_capable(mnt_userns, inode))
+	if (!inode_owner_or_capable(mnt_idmap_owner(idmap), inode))
 		return -EPERM;
 
 	inode_lock(inode);
@@ -693,7 +693,7 @@ int vfs_fileattr_set(struct user_namespace *mnt_userns, struct dentry *dentry,
 		}
 		err = fileattr_set_prepare(inode, &old_ma, fa);
 		if (!err)
-			err = inode->i_op->fileattr_set(mnt_userns, dentry, fa);
+			err = inode->i_op->fileattr_set(idmap, dentry, fa);
 	}
 	inode_unlock(inode);
 
@@ -714,7 +714,7 @@ static int ioctl_getflags(struct file *file, unsigned int __user *argp)
 
 static int ioctl_setflags(struct file *file, unsigned int __user *argp)
 {
-	struct user_namespace *mnt_userns = file_mnt_user_ns(file);
+	struct mnt_idmap *idmap = file_mnt_idmap(file);
 	struct dentry *dentry = file->f_path.dentry;
 	struct fileattr fa;
 	unsigned int flags;
@@ -725,7 +725,7 @@ static int ioctl_setflags(struct file *file, unsigned int __user *argp)
 		err = mnt_want_write_file(file);
 		if (!err) {
 			fileattr_fill_flags(&fa, flags);
-			err = vfs_fileattr_set(mnt_userns, dentry, &fa);
+			err = vfs_fileattr_set(idmap, dentry, &fa);
 			mnt_drop_write_file(file);
 		}
 	}
@@ -746,7 +746,7 @@ static int ioctl_fsgetxattr(struct file *file, void __user *argp)
 
 static int ioctl_fssetxattr(struct file *file, void __user *argp)
 {
-	struct user_namespace *mnt_userns = file_mnt_user_ns(file);
+	struct mnt_idmap *idmap = file_mnt_idmap(file);
 	struct dentry *dentry = file->f_path.dentry;
 	struct fileattr fa;
 	int err;
@@ -755,7 +755,7 @@ static int ioctl_fssetxattr(struct file *file, void __user *argp)
 	if (!err) {
 		err = mnt_want_write_file(file);
 		if (!err) {
-			err = vfs_fileattr_set(mnt_userns, dentry, &fa);
+			err = vfs_fileattr_set(idmap, dentry, &fa);
 			mnt_drop_write_file(file);
 		}
 	}