Size of returned file after first call is wrong

[nschlia]

When a file is opened for the first time, the resulting file has the wrong size:

• If the file is larger than predicted, the result file is truncated to the predicted size. Excess bytes are discarded.
• If the file is smaller a read error is returned

When the file is accessed once more (read from cache), the size is correct.

[nschlia]

The direct_io option is required if the file size is not known in advance.

direct_io
              This option disables the use of page cache (file content  cache)
              in the kernel for this filesystem. This has several affects:
       1.     Each  read(2)  or write(2) system call will initiate one or more
              read or write operations, data will not be cached in the kernel.
       2.     The return value of the read() and  write()  system  calls  will
              correspond   to   the  return  values  of  the  read  and  write
              operations. This is useful for example if the file size  is  not
              known in advance (before reading it)

[nschlia]

Fixed.

[nschlia]

Note: For older versions (1.1 or older) this can be fixed by specifying the direct_io option on the command line.