VOP_ALLOCATE — allocate storage for a file

       This  call  allocates  storage  for  a  range  of  offsets  in  a  file.   It  is  used  to implement the
       posix_fallocate system call.

       Its arguments are:

       vp      The vnode of the file.

       offset  The start of the range to allocate storage for in the file.

       len     The length of the range to allocate storage for in the file.

       The offset and len arguments are updated to reflect the portion of the  range  that  still  needs  to  be
       allocated on return.  A partial allocation is considered a successful operation.  The file's contents are
       not changed.

       [EFBIG]            An  attempt was made to write a file that exceeds the process's file size limit or the
                          maximum file size.

       [ENOSPC]           The file system is full.

       [EPERM]            An append-only flag is set on the file, but the caller is attempting to  write  before
                          the current end of file.

       The file should be exclusively locked on entry and will still be locked on exit.

       VOP_ALLOCATE — allocate storage for a file

       Zero is returned if the call is successful, otherwise an appropriate error code is returned.

vnode(9), VOP_READ(9), VOP_WRITE(9)

Debian                                           October 3, 2013                                 VOP_ALLOCATE(9)

#include<sys/param.h>#include<sys/vnode.h>intVOP_ALLOCATE(structvnode*vp, off_t*offset, off_t*len);