Index: stable/12/share/man/man9/VOP_GETPAGES.9
===================================================================
--- stable/12/share/man/man9/VOP_GETPAGES.9	(revision 350164)
+++ stable/12/share/man/man9/VOP_GETPAGES.9	(revision 350165)
@@ -1,207 +1,207 @@
 .\" -*- nroff -*-
 .\"
 .\" Copyright (c) 1996 Doug Rabson
 .\" Copyright 2003, Garrett A. Wollman
 .\"
 .\" All rights reserved.
 .\"
 .\" This program is free software.
 .\"
 .\" Redistribution and use in source and binary forms, with or without
 .\" modification, are permitted provided that the following conditions
 .\" are met:
 .\" 1. Redistributions of source code must retain the above copyright
 .\"    notice, this list of conditions and the following disclaimer.
 .\" 2. Redistributions in binary form must reproduce the above copyright
 .\"    notice, this list of conditions and the following disclaimer in the
 .\"    documentation and/or other materials provided with the distribution.
 .\"
 .\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
 .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 .\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 .\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
 .\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 .\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 .\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
 .\" $FreeBSD$
 .\"
-.Dd May 7, 2017
+.Dd June 29, 2019
 .Dt VOP_GETPAGES 9
 .Os
 .Sh NAME
 .Nm VOP_GETPAGES ,
 .Nm VOP_PUTPAGES
 .Nd read or write VM pages from a file
 .Sh SYNOPSIS
 .In sys/param.h
 .In sys/vnode.h
 .In vm/vm.h
 .Ft int
 .Fo VOP_GETPAGES
 .Fa "struct vnode *vp"
 .Fa "vm_page_t *ma"
 .Fa "int count"
 .Fa "int *rbehind"
 .Fa "int *rahead"
 .Fc
 .Ft int
 .Fo VOP_PUTPAGES
 .Fa "struct vnode *vp"
 .Fa "vm_page_t *ma"
 .Fa "int bytecount"
 .Fa "int flags"
 .Fa "int *rtvals"
 .Fc
 .Sh DESCRIPTION
 The
 .Fn VOP_GETPAGES
 method is called to read in pages of virtual memory which are backed by
 ordinary files.
 If other adjacent pages are backed by adjacent regions of the same file,
 .Fn VOP_GETPAGES
 is requested to read those pages as well, although it is not required to
 do so.
 The
 .Fn VOP_PUTPAGES
 method does the converse; that is to say, it writes out adjacent dirty
 pages of virtual memory.
 .Pp
 On entry, the vnode lock is held but neither the page queue nor VM object
 locks are held.
 Both methods return in the same state on both success and error returns.
 .Pp
 The arguments are:
 .Bl -tag -width rbehind
 .It Fa vp
 The file to access.
 .It Fa ma
 Pointer to the first element of an array of pages representing a
 contiguous region of the file to be read or written.
 .It Fa count
 The length of the
 .Fa ma
 array.
 .It Fa bytecount
 The number of bytes that should be written from the pages of the array.
 .It Fa flags
 A bitfield of flags affecting the function operation.
 If
 .Dv VM_PAGER_PUT_SYNC
 is set, the write should be synchronous; control must not be returned
 to the caller until after the write is finished.
 If
 .Dv VM_PAGER_PUT_INVAL
 is set, the pages are to be invalidated after being written.
 If
 .Dv VM_PAGER_PUT_NOREUSE
 is set, the I/O performed should set the IO_NOREUSE flag, to indicate
 to the filesystem that pages should be marked for fast reuse if needed.
 This could occur via a call to
 .Xr vm_page_deactivate_noreuse 9 ,
 which puts such pages onto the head of the inactive queue.
 If
 .Dv VM_PAGER_CLUSTER_OK
-is set, writes may be performed asynchronously, so that related writes
+is set, writes may be delayed, so that related writes
 can be coalesced for efficiency, e.g.,
 using the clustering mechanism of the buffer cache.
 .It Fa rtvals
 An array of VM system result codes indicating the status of each
 page written by
 .Fn VOP_PUTPAGES .
 .It Fa rbehind
 Optional pointer to integer specifying number of pages to be read behind, if
 possible.
 If the filesystem supports that feature, number of actually read pages is
 reported back, otherwise zero is returned.
 .It Fa rahead
 Optional pointer to integer specifying number of pages to be read ahead, if
 possible.
 If the filesystem supports that feature, number of actually read pages is
 reported back, otherwise zero is returned.
 .El
 .Pp
 The status of the
 .Fn VOP_PUTPAGES
 method is returned on a page-by-page basis in the array
 .Fa rtvals[] .
 The possible status values are as follows:
 .Bl -tag -width VM_PAGER_ERROR
 .It Dv VM_PAGER_OK
 The page was successfully written.
 The implementation must call
 .Xr vm_page_undirty 9
 to mark the page as clean.
 .It Dv VM_PAGER_PEND
 The page was scheduled to be written asynchronously.
 When the write completes, the completion callback should
 call
 .Xr vm_object_pip_wakeup 9
 and
 .Xr vm_page_sunbusy 9
 to clear the busy flag and awaken any other threads waiting for this page,
 in addition to calling
 .Xr vm_page_undirty 9 .
 .It Dv VM_PAGER_BAD
 The page was entirely beyond the end of the backing file.
 This condition should not be possible if the vnode's file system
 is correctly implemented.
 .It Dv VM_PAGER_ERROR
 The page could not be written because of an error on the underlying storage
 medium or protocol.
 .It Dv VM_PAGER_FAIL
 Treated identically to
 .Dv VM_PAGER_ERROR .
 .It Dv VM_PAGER_AGAIN
 The page was not handled by this request.
 .El
 .Pp
 The
 .Fn VOP_GETPAGES
 method must populate and validate all requested pages in order to
 return success.
 It is expected to release any pages in
 .Fa ma
 that it does not successfully handle, by calling
 .Xr vm_page_free 9 .
 When it succeeds,
 .Fn VOP_GETPAGES
 must set the valid bits appropriately.
 Upon entry to
 .Fn VOP_GETPAGES ,
 all pages in
 .Fa ma
 are busied exclusively.
 Upon successful return, the pages must all be busied exclusively
 as well, but pages may be unbusied during processing.
 The filesystem is responsible for activating paged-out pages, but this
 does not necessarily need to be done within
 .Fn VOP_GETPAGES
 depending on the architecture of the particular filesystem.
 .Sh RETURN VALUES
 If it successfully reads all pages in
 .Fa ma ,
 .Fn VOP_GETPAGES
 returns
 .Dv VM_PAGER_OK ;
 otherwise, it returns
 .Dv VM_PAGER_ERROR .
 By convention, the return value of
 .Fn VOP_PUTPAGES
 is
 .Fa rtvals[0] .
 .Sh SEE ALSO
 .Xr vm_object_pip_wakeup 9 ,
 .Xr vm_page_free 9 ,
 .Xr vm_page_sunbusy 9 ,
 .Xr vm_page_undirty 9 ,
 .Xr vm_page_xunbusy 9 ,
 .Xr vnode 9
 .Sh AUTHORS
 This manual page was written by
 .An Doug Rabson
 and then substantially rewritten by
 .An Garrett Wollman .
Index: stable/12
===================================================================
--- stable/12	(revision 350164)
+++ stable/12	(revision 350165)

Property changes on: stable/12
___________________________________________________________________
Modified: svn:mergeinfo
## -0,0 +0,1 ##
   Merged /head:r349543