VN_DEALLOCATE(9) FreeBSD Kernel Developer's Manual VN_DEALLOCATE(9)
NAME
vn_deallocate - zero and/or deallocate storage from a file
SYNOPSIS
#include <sys/param.h>
#include <sys/vnode.h>
int
vn_deallocate(struct vnode *vp, off_t *offset, off_t *length, int flags,
int ioflag, struct ucred *active_cred, struct ucred *file_cred);
DESCRIPTION
The vn_deallocate() function zeros and/or deallocates backing storage
space from a file. This function only works on vnodes with VREG type.
The arguments are:
vp The vnode of the file.
offset The starting offset of the operation range.
length The length of the operation range. This must be greater
than 0.
flags The control flags of the operation. This should be set to 0
for now.
ioflag Directives and hints to be given to the file system.
active_cred The user credentials of the calling thread.
file_cred The credentials installed on the file description pointing
to the vnode or NOCRED.
The ioflag() argument gives directives and hints to the file system. It
may include one or more of the following flags:
IO_NODELOCKED The vnode was locked before the call.
IO_RANGELOCKED Rangelock was owned around the call.
IO_NOMACCHECK Skip MAC checking in the call.
IO_SYNC Do I/O synchronously.
IO_DIRECT Attempt to bypass buffer cache.
*offset and *length are updated to reflect the unprocessed operation
range of the call. For a successful completion, *length is updated to be
the value 0, and *offset is incremented by the number of bytes zeroed
before the end-of-file.
RETURN VALUES
Upon successful completion, the value 0 is returned; otherwise the
appropriate error is returned.
SEE ALSO
vnode(9), VOP_DEALLOCATE(9)
AUTHORS
vn_deallocate and this manual page was written by Ka Ho Ng
<
[email protected]> under sponsorship from the FreeBSD Foundation.
FreeBSD 14.1-RELEASE-p8 August 25, 2021 FreeBSD 14.1-RELEASE-p8