Re: [PATCH] fs/ntfs3: Fix logic in ntfs_cmp_names_cpu

[Mark Harmstone <mark@harmstone.com>]

On 7/10/21 15:33, Konstantin Komarov wrote:

 > This is optimized way of this algorithm ( from comment to ntfs_cmp_names ):
 >   * Straight way to compare names:
 >   * - Case insensitive
 >   * - If name equals and 'upcase' then
 >   * - Case sensitive

You have your first and third bullet points the wrong way round there. Am I
right then that the current case-insensitivity stuff is purely to determine
where the name goes in the $I30 B-tree?

 > I think, that ntfs3 need to be case sensitive.
 > And listed things, that I think support my opinion.
 > That's why I've mentioned that ntfs.sys is case sensitive.
 > That's why I've mentioned FILE_FLAG_POSIX_SEMANTICS and
 > FileCaseSensitiveInformation.
 > I don't think, that copying win32 api behavior is good,
 > when Microsoft makes steps to make ntfs work in posix way.

I'm surprised that what I wrote is controversial... NTFS is a case-insensitive
filesystem, that allows specific directories to override this with a flag. You
might wish it were otherwise, but the NTFS specification is defined by what
Microsoft's driver does.

Your driver lets me create a file called foo.txt and one called FOO.TXT in a
normal directory, and when I double-click on one in Windows the wrong file gets
opened. That's 100% a bug.

It's worth pointing out that the Linux vfat driver handles case-sensitivity on
Microsoft's other filesystem correctly.