freebsd man page for vop_allocate

VOP_ALLOCATE(9) 					   BSD Kernel Developer's Manual					   VOP_ALLOCATE(9)

NAME
     VOP_ALLOCATE -- allocate storage for a file

SYNOPSIS
     #include <sys/param.h>
     #include <sys/vnode.h>

     int
     VOP_ALLOCATE(struct vnode *vp, off_t *offset, off_t *len);

DESCRIPTION
     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 alloca-
     tion is considered a successful operation.  The file's contents are not changed.

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

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

ERRORS
     [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.

SEE ALSO
     vnode(9), VOP_READ(9), VOP_WRITE(9)

BSD
								  October 3, 2013							       BSD