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VNODE_PAGER_SETSIZE(9) FreeBSD Kernel Developer's Manual
NAME
vnode_pager_setsize - notify the VM system about updates in the file size
SYNOPSIS
#include <sys/param.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
void
vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize);
DESCRIPTION
vnode_pager_setsize lets the VM system know about a change in size for a
file, and updates the object size and vnode pager size of the vm object
in vp with nsize. Page faults on the object mapping with offset beyond
the new object size results in SIGBUS.
Pages between the old EOF and the new EOF are removed from the object
queue if the file size shrinks. In case the new EOF specified by the
nsize argument is not aligned to page boundary, partial-page area
starting beyond the EOF is zeroed and marked invalid. if the page exists
resident.
In case the vnode vp does not have a VM object allocated, the effect of
calling this function is no-op.
This function must be used within file system code to implement
truncation if the file system allocates vm objects for vnodes.
LOCKS
The vnode should be exclusively locked on entry and will still be locked
on exit.
SEE ALSO
vnode(9)
HISTORY
The vnode_pager_setsize manual page first appeared in FreeBSD 14.
AUTHORS
This manual page was written by Ka Ho Ng <khng@FreeBSD.org>.
FreeBSD 14.0-RELEASE-p6 April 8, 2021 FreeBSD 14.0-RELEASE-p6