VOP_DEALLOCATE(9)

VOP_DEALLOCATE9

Zero and/or deallocate storage from a file

Usage

#include <sys/param.h>

#include <sys/vnode.h>

int

VOP_DEALLOCATE(struct vnode *vp, off_t *offset, off_t *len, int flags, int ioflag, struct ucred *cred);

Overview

This VOP call zeroes/deallocates storage for an offset range in a file. It is used to implement the fspacectl(2) system call.

Its arguments are:

vp

The vnode of the file.

offset

The start of the range to deallocate storage in the file.

len

The length of the range to deallocate storage in the file.

flags

The flags of this call. This should be set to 0 for now.

ioflag

Directives and hints to be given to the file system.

cred

The credentials of the caller.

*offset and *len are updated to reflect the portion of the range that still needs to be zeroed/deallocated on return. Partial result is considered a successful operation. For a non-partial successful completion, *len is updated to be the value 0, and *offset is incremented by the number of bytes zeroed before the end-of-file.

Locks

The vnode should be 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

[EINVAL]

Invalid offset, len, or flags parameters are passed into this VOP call.

[ENODEV]

The vnode type is not supported by this VOP call.

[ENOSPC]

The file system is full.

[EPERM]

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

Releases

Unchanged in 9 releases since FreeBSD 14.0-RELEASE.

  1. 14.0–16.0

Authors

VOP_DEALLOCATE and this manual page was written by Ka Ho Ng ⟨[email protected]⟩ under sponsorship from the FreeBSD Foundation.

From base 16.0-CURRENT-20261027-61c70dc16a79 in FreeBSD 16.0-CURRENT (2026-10-27). Parsed by carta from the page's mdoc source.