From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/tools/hv/hv_vss_daemon.c | 64 ++++++++++++++++++++------------
1 files changed, 40 insertions(+), 24 deletions(-)
diff --git a/kernel/tools/hv/hv_vss_daemon.c b/kernel/tools/hv/hv_vss_daemon.c
index c2bb8a3..dd11187 100644
--- a/kernel/tools/hv/hv_vss_daemon.c
+++ b/kernel/tools/hv/hv_vss_daemon.c
@@ -1,20 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* An implementation of the host initiated guest snapshot for Hyper-V.
*
- *
* Copyright (C) 2013, Microsoft, Inc.
* Author : K. Y. Srinivasan <kys@microsoft.com>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published
- * by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
- * NON INFRINGEMENT. See the GNU General Public License for more
- * details.
- *
*/
@@ -39,6 +28,8 @@
#include <stdbool.h>
#include <dirent.h>
+static bool fs_frozen;
+
/* Don't use syslog() in the function since that can cause write to disk */
static int vss_do_freeze(char *dir, unsigned int cmd)
{
@@ -53,7 +44,7 @@
* If a partition is mounted more than once, only the first
* FREEZE/THAW can succeed and the later ones will get
* EBUSY/EINVAL respectively: there could be 2 cases:
- * 1) a user may mount the same partition to differnt directories
+ * 1) a user may mount the same partition to different directories
* by mistake or on purpose;
* 2) The subvolume of btrfs appears to have the same partition
* mounted more than once.
@@ -166,17 +157,26 @@
continue;
}
error |= vss_do_freeze(ent->mnt_dir, cmd);
- if (error && operation == VSS_OP_FREEZE)
- goto err;
+ if (operation == VSS_OP_FREEZE) {
+ if (error)
+ goto err;
+ fs_frozen = true;
+ }
}
endmntent(mounts);
if (root_seen) {
error |= vss_do_freeze("/", cmd);
- if (error && operation == VSS_OP_FREEZE)
- goto err;
+ if (operation == VSS_OP_FREEZE) {
+ if (error)
+ goto err;
+ fs_frozen = true;
+ }
}
+
+ if (operation == VSS_OP_THAW && !error)
+ fs_frozen = false;
goto out;
err:
@@ -186,6 +186,7 @@
endmntent(mounts);
}
vss_operate(VSS_OP_THAW);
+ fs_frozen = false;
/* Call syslog after we thaw all filesystems */
if (ent)
syslog(LOG_ERR, "FREEZE of %s failed; error:%d %s",
@@ -207,13 +208,13 @@
int main(int argc, char *argv[])
{
- int vss_fd, len;
+ int vss_fd = -1, len;
int error;
struct pollfd pfd;
int op;
struct hv_vss_msg vss_msg[1];
int daemonize = 1, long_index = 0, opt;
- int in_handshake = 1;
+ int in_handshake;
__u32 kernel_modver;
static struct option long_options[] = {
@@ -243,6 +244,18 @@
openlog("Hyper-V VSS", 0, LOG_USER);
syslog(LOG_INFO, "VSS starting; pid is:%d", getpid());
+reopen_vss_fd:
+ if (vss_fd != -1)
+ close(vss_fd);
+ if (fs_frozen) {
+ if (vss_operate(VSS_OP_THAW) || fs_frozen) {
+ syslog(LOG_ERR, "failed to thaw file system: err=%d",
+ errno);
+ exit(EXIT_FAILURE);
+ }
+ }
+
+ in_handshake = 1;
vss_fd = open("/dev/vmbus/hv_vss", O_RDWR);
if (vss_fd < 0) {
syslog(LOG_ERR, "open /dev/vmbus/hv_vss failed; error: %d %s",
@@ -295,8 +308,7 @@
if (len != sizeof(struct hv_vss_msg)) {
syslog(LOG_ERR, "read failed; error:%d %s",
errno, strerror(errno));
- close(vss_fd);
- return EXIT_FAILURE;
+ goto reopen_vss_fd;
}
op = vss_msg->vss_hdr.operation;
@@ -323,14 +335,18 @@
default:
syslog(LOG_ERR, "Illegal op:%d\n", op);
}
+
+ /*
+ * The write() may return an error due to the faked VSS_OP_THAW
+ * message upon hibernation. Ignore the error by resetting the
+ * dev file, i.e. closing and re-opening it.
+ */
vss_msg->error = error;
len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
if (len != sizeof(struct hv_vss_msg)) {
syslog(LOG_ERR, "write failed; error: %d %s", errno,
strerror(errno));
-
- if (op == VSS_OP_FREEZE)
- vss_operate(VSS_OP_THAW);
+ goto reopen_vss_fd;
}
}
--
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