Comment 3 for bug 2063369

Today, we don't create the sparse file "with the required size" when it is first opened. We could try seeking to maximum size of the device and writing a single byte, and seeing whether or not that fails, and if it fails, *assume* that this was caused by the target file system not supporting such a large file. There are other reasons why the write might fail (for example, the system administrator or some supervisor program might have set a file size limit via the setrlimit(3) systme call or the /etc/security/limits.h file.

Also note not there is no supported way for a userspace program to query the kernel to find the maximum file size supported by a particular file system. It will depend on the file system type, the file system block size, and potentially, file system features that might be enabled on a particular file system.

I agree that it would be nice to print a more user-friendly error message, and right away, as opposed after writing up to 16TB of image file. We just want to make sure if the system administrator has set a maximum file size of say, 2 GiB, and we print a message that it's a file system limitation, that will be confusing and will result in my getting angry bug reports. :-)