Re: [PATCH 3/6] fs: sort out the fallocate mode vs flag mess

Christoph Hellwig
2024-08-21T13:14:32Z

On Wed, Aug 21, 2024 at 08:43:14AM -0400, Brian Foster wrote:
> > - if ((mode & ~FALLOC_FL_KEEP_SIZE) && IS_APPEND(inode))
> > + if (mode != FALLOC_FL_ALLOCATE_RANGE && IS_APPEND(inode))
> > return -EPERM;
>
> Unless I'm misreading, this changes semantics by enforcing that we
> cannot use KEEP_SIZE on append only files. That means one can no longer
> do a post-eof prealloc without actually changing the file size, which on
> a quick test seems to work today.

No, I think it was me misreading the old code. And I'm a little worried
that no test cought it.