Last modified date isn't preserved when copying file to file share

[buttercookie42]

If I copy a file (using Windows Explorer) to a jfileserver share (using version 1.4.0), the last modified date isn't preserved.

Looking at a Wireshark capture, what happens during the file copy is that

1. The file is created
2. The file is being written to.
3. SetFileInformation is called to set the last modified date to the source file's date.
4. The file is closed.

I strongly suspect that the bug happens because writing to a file only increments its write count, but doesn't yet update the file's last modified date. That process only happens when the file is being closed, with the unfortunate side effect that any SetFileInformation calls that happened between the last file write and the file being closed therefore get overwritten.

[FileSysOrg]

Which filesystem are you using ?

[buttercookie42]

I'm using the JavaNIODiskDriver to access my Android phone's filesystem.

[buttercookie42]

And I've checked, and a pure last modified date update without any other writes does make it through, so it's not Android being picky about non-root apps setting the last modified date.

[FileSysOrg]

The JavaNIODiskDriver is a simpler filesystem, the only set file information call it supports is the set modify date call, which will set it on the file immediately. It may be that the file close causes the modify date to be reset.

Can you change the sequence so that you write the file, close it then set the original modify date to see if the update is ok then ?.

Would it be possible to send me the packet trace ?, to gk.spencer@filesys.org.

[buttercookie42]

It may be that the file close causes the modify date to be reset.

That's what I suspect, yeah. I do even have a potential idea for a possible fix (a "last modified date dirty" flag on the network file – incrementing the write count would set it to dirty, manually updating the date via SetFileInformation back to clean and then a file close would update the date only if it's dirty), but I'd need a bit to get a separate build of jfileserver going, because right now I'm still only using it as a packaged dependency.

Can you change the sequence so that you write the file, close it then set the original modify date to see if the update is ok then ?

Sort of, yes. Not directly, because like I said I'm just using Windows Explorer, so I don't really have control over all the low-level operations that happen when copying a file. However I can change the last modified date separately afterwards, and like I mentioned above, that does work successfully.

Would it be possible to send me the packet trace ?

Can do.