drag and drop from shared folder, file not updated

[RoteAdler]

with linux kernel 3.x guest the file size is updated, but the content is just truncated:

- check that you have access to a host shared folder, like your Desktop:
	ls /media/sf_Desktop/
- make a soft link to the shared folder:
	ln -s /media/sf_Desktop/ HostDesktop
- using host, create a text file in your shared folder with:
	The quick brown fox jumps over the lazy dog
- using guest, open the HostDesktop folder and drag the text file to guest desktop:
	»
- using host, change the text file:
	The fox jumps over the lazy dog
- using guest, drag the text file to guest desktop, accept replacement:
	»
- check the dragged file, it may be wrong:
	The quick brown fox jumps over 

copy is ok if the file is replaced with a cp command, or drag'n'drop directly from host to guest.

tested with windows 7 host and ubuntu 12.04, ubuntu 13.10, fedora 17, centOS 6.4, windows 7 and windows xp guests; windows and centos (kernel 2.6) are ok, others (kernel 3.x) are wrong; same problem with ubuntu 12.04 host and ubuntu 13.10 guest.

also checked in 4.2 vbox, with same results (only 2~3 tests)

[MatthewLM]

I can confirm that this problem occurs with me when using OSX Mountain Lion 10.8.4 as the host OS and Linux Mint 13 as the guest. I am using VirtualBox 4.3.6. This also occurs when making the file larger. Occasionally the new file will not be copied over. Instead the old file remains in place and the length of the file is changed such that there are null bytes at the end.

It happens regularly enough to make using VirtualBox a very large pain.

[aeichner]

Please reopen if still relevant with a recent VirtualBox release.