Re: [PATCH 11/11] fsverity: use a hashtable to find the fsverity_info

[Matthew Wilcox <willy@infradead.org>]

On Mon, Jan 26, 2026 at 12:12:06PM -0800, Eric Biggers wrote:
> When CONFIG_FS_VERITY=n, there can still be inodes that have fsverity
> enabled, since they might have already been present on the filesystem.
> The S_VERITY flag and the corresponding IS_VERITY() macro are being used
> to identify such inodes and handle them appropriately.  
> 
> Consider fsverity_file_open() for example:
> 
> static inline int fsverity_file_open(struct inode *inode, struct file *filp)
> {
> 	if (IS_VERITY(inode))
> 		return __fsverity_file_open(inode, filp);
> 	return 0;
> }
> 
> When CONFIG_FS_VERITY=n, __fsverity_file_open() resolves to the stub:
> 
> static inline int __fsverity_file_open(struct inode *inode, struct file *filp)
> {
> 	return -EOPNOTSUPP;
> }
> 
> So the result is that on a kernel that doesn't have fsverity support
> enabled, trying to open an fsverity file fails with EOPNOTSUPP.

... why?  If the user has built a kernel without VERITY support enabled,
they're no longer allowed to open files with verity metadata?  I can't
see the harm in allowing them to read these files, they're just not
protected against these files being corrupted.