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authorpooka <pooka@NetBSD.org>2007-01-26 23:55:27 +0000
committerpooka <pooka@NetBSD.org>2007-01-26 23:55:27 +0000
commitf4e2aba8ceddced39477e300033559293df38df2 (patch)
tree3a6a447f6312defed6f78a77f5b544756c0bc5c7
parent3238d589b27380cb95cf5e2afd8a8f633bd00178 (diff)
document puffs_fs_suspend()
-rw-r--r--lib/libpuffs/Makefile4
-rw-r--r--lib/libpuffs/puffs.33
-rw-r--r--lib/libpuffs/puffs_suspend.395
3 files changed, 99 insertions, 3 deletions
diff --git a/lib/libpuffs/Makefile b/lib/libpuffs/Makefile
index 389e2f39a2d..2e48e864c97 100644
--- a/lib/libpuffs/Makefile
+++ b/lib/libpuffs/Makefile
@@ -1,4 +1,4 @@
-# $NetBSD: Makefile,v 1.12 2007/01/26 23:00:33 pooka Exp $
+# $NetBSD: Makefile,v 1.13 2007/01/26 23:55:27 pooka Exp $
#
.include <bsd.own.mk>
@@ -9,7 +9,7 @@ LIB= puffs
SRCS= puffs.c callcontext.c creds.c flush.c null.c opdump.c \
paths.c pnode.c requests.c subr.c suspend.c
MAN= puffs.3 puffs_cc.3 puffs_flush.3 puffs_node.3 \
- puffs_path.3 puffs_req.3
+ puffs_path.3 puffs_req.3 puffs_suspend.3
INCS= puffs.h puffsdump.h
INCSDIR= /usr/include
LINTFLAGS+=-S -w
diff --git a/lib/libpuffs/puffs.3 b/lib/libpuffs/puffs.3
index 57893065b63..cfe4e5fc1bf 100644
--- a/lib/libpuffs/puffs.3
+++ b/lib/libpuffs/puffs.3
@@ -1,4 +1,4 @@
-.\" $NetBSD: puffs.3,v 1.11 2007/01/20 15:10:38 pooka Exp $
+.\" $NetBSD: puffs.3,v 1.12 2007/01/26 23:55:27 pooka Exp $
.\"
.\" Copyright (c) 2006, 2007 Antti Kantee. All rights reserved.
.\"
@@ -588,6 +588,7 @@ If this is zero, the kernel will call reclaim immediately.
.Xr puffs_node 3 ,
.Xr puffs_path 3 ,
.Xr puffs_req 3 ,
+.Xr puffs_suspend 3 ,
.Xr puffs 4
.Sh HISTORY
An unsupported experimental version of
diff --git a/lib/libpuffs/puffs_suspend.3 b/lib/libpuffs/puffs_suspend.3
new file mode 100644
index 00000000000..0f5e56679ac
--- /dev/null
+++ b/lib/libpuffs/puffs_suspend.3
@@ -0,0 +1,95 @@
+.\" $NetBSD: puffs_suspend.3,v 1.1 2007/01/26 23:55:27 pooka Exp $
+.\"
+.\" Copyright (c) 2007 Antti Kantee. All rights reserved.
+.\"
+.\" 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 AUTHOR AND CONTRIBUTORS ``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 AUTHOR OR CONTRIBUTORS 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.
+.\"
+.Dd January 27, 2007
+.Dt PUFFS_SUSPEND 3
+.Os
+.Sh NAME
+.Nm puffs_suspend
+.Nd puffs file system suspension and snapshotting
+.Sh LIBRARY
+.Lb libpuffs
+.Sh SYNOPSIS
+.In puffs.h
+.Ft int
+.Fn puffs_fs_suspend "struct puffs_usermount *pu"
+.Sh DESCRIPTION
+.Em IMPORTANT NOTE!
+This document describes interfaces which are not yet guaranteed to be
+stable.
+In case you update your system sources, please recompile everything
+and fix complation errors.
+If your sources are out-of-sync, incorrect operation may result.
+The interfaces in this document will most likely be hugely simplified
+in later versions or made transparent to the implementation.
+.Pp
+The function
+.Fn puffs_fs_suspend
+requests the kernel to suspend operations to the file system indicated by
+.Fa pu .
+There are several possible outcomes: nothing, an error or success.
+These will be indicated through the callback of the same name.
+The file system must set this callback if it wants to be notified of
+file system suspension.
+The interface call itself returns 0 on success or \-1 on error and
+sets
+.Va errno .
+In case an error is returned, the callback will never be called.
+However, the converse does not hold and the callback may never be
+called even if the library call is succesful.
+.Pp
+In case the kernel is succesful to start suspending the file system,
+the callback is called with status
+.Dv PUFFS_SUSPEND START .
+The file system implementation may use this as a hint on how to handle
+following operations.
+Once the file system has succesfully been suspended, the status
+.Dv PUFFS_SUSPEND_SUSPENDED
+will be delivered.
+In case there was an error while suspending,
+.Dv PUFFS_SUSPEND_ERROR
+is given.
+This effectively nullifies any
+.Dv PUFFS_SUSPEND_START
+given earlier.
+Operation will automatically resume after suspension and the status
+.Dv PUFFS_SUSPEND_RESUME
+is delivered to the callback.
+Error or success is always provided in case start is given.
+.Pp
+The file system is supposed to do a file system specific snapshotting
+routine when it receives
+.Dv PUFFS_SUSPEND_SUSPENDED .
+.Sh SEE ALSO
+.Xr puffs 3 ,
+.Xr puffs_cc 3
+.Sh BUGS
+Currently the implementation works only for single-threaded file systems
+which do not use
+.Nm puffs_cc .
+.Pp
+File system data and metadata are not always totally correctly
+synchronized at suspend.
+This will be fixed soon.