From: Corinna Vinschen <corinna-cygwin@cygwin.com>
To: cygwin@cygwin.com
Subject: Re: ls/stat on OneDrive causes download of files
Date: Wed, 6 Mar 2024 14:28:14 +0100 [thread overview]
Message-ID: <ZehvbhVizZTBSaRR@calimero.vinschen.de> (raw)
In-Reply-To: <ZehuDAKd3ceXlfba@calimero.vinschen.de>
On Mar 6 14:22, Corinna Vinschen via Cygwin wrote:
> On Mar 5 19:54, Marcin Wisnicki via Cygwin wrote:
> > If I invoke ls or anything else that does stat inside OneDrive folder
> > it will trigger download of all files.
> >
> > OneDrive uses placeholder files[1] to represent remote files.
> >
> > I'm guessing reading file content in stat is to support detection of
> > actually executable files as in here[2]?
> >
> > I think this should be disabled on non-hydrated placeholder files.
> > Running `find` or 'ls -R` and having your entire OneDrive downloaded
> > is extremely problematic.
> >
> > I could live without executable scripts in the OneDrive folder and
> > it's easy to mark files as always offline to solve it.
> >
> > Another idea is to skip checking files with extensions known to be
> > non-executable such as jpg (or just any extensions that is not known
> > to be executable).
>
> Nothing of this makes sense from a POSIX library POV. The library can
> either not handle placeholder files specially, as today, or it can
> handle them all the same way.
>
> Given these placeholder files are actually reparse points of type
> IO_REPARSE_TAG_FILE_PLACEHOLDER, we can handle them as symbolic links.
>
> However, the structure of the IO_REPARSE_TAG_FILE_PLACEHOLDER reparse
> data buffer is undocumented. It would be helpful if somebody using
> OneDrive would examine the content of the attached REPARSE_DATA_BUFFER.
>
> > [2] https://github.com/msys2/msys2-runtime/blob/msys2-3.4.10/winsup/cygwin/fhandler/disk_file.cc#L548
>
> The NtReadFile call at this point is not the problem. It would be
> helpful to point to Cygwin's source instead of MSYS2, btw.
Oh, btw., this is from
https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-fscc/c8e77b37-3909-4fe6-a4ea-2b9d423b1ee4:
IO_REPARSE_TAG_FILE_PLACEHOLDER
0x80000015
Obsolete.
---------
Used by Windows Shell for legacy placeholder files in Windows 8.1.
Server-side interpretation only, not meaningful over the wire.
So even if we support them, what is their replacement in W10 and later?
Corinna
next prev parent reply other threads:[~2024-03-06 13:28 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-06 0:54 Marcin Wisnicki
2024-03-06 13:22 ` Corinna Vinschen
2024-03-06 13:28 ` Corinna Vinschen [this message]
2024-03-06 13:54 ` Brian Inglis
2024-03-06 17:19 ` Corinna Vinschen
2024-03-06 18:55 ` Jeffrey Altman
2024-03-06 19:14 ` Corinna Vinschen
2024-03-07 9:06 ` Corinna Vinschen
2024-03-08 10:37 ` Corinna Vinschen
2024-03-08 12:52 ` Thomas Wolff
2024-03-08 13:15 ` Jeffrey Altman
2024-03-08 13:56 ` Corinna Vinschen
2024-03-08 22:21 ` Corinna Vinschen
2024-03-08 22:26 ` Marcin Wisnicki
2024-03-09 20:29 ` Marcin Wisnicki
2024-03-11 17:04 ` Corinna Vinschen
2024-03-06 19:00 ` Corinna Vinschen
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