diff options
Diffstat (limited to 'tools/hv/hv_vss_daemon.c')
| -rw-r--r-- | tools/hv/hv_vss_daemon.c | 66 |
1 files changed, 42 insertions, 24 deletions
diff --git a/tools/hv/hv_vss_daemon.c b/tools/hv/hv_vss_daemon.c index b13300172762..dd111870beee 100644 --- a/tools/hv/hv_vss_daemon.c +++ b/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 @@ static int vss_do_freeze(char *dir, unsigned int cmd) * 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. @@ -166,18 +157,27 @@ static int vss_operate(int operation) 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: save_errno = errno; @@ -186,6 +186,7 @@ err: 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 @@ void print_usage(char *argv[]) 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[] = { @@ -229,6 +230,8 @@ int main(int argc, char *argv[]) daemonize = 0; break; case 'h': + print_usage(argv); + exit(0); default: print_usage(argv); exit(EXIT_FAILURE); @@ -241,6 +244,18 @@ int main(int argc, char *argv[]) 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", @@ -293,8 +308,7 @@ int main(int argc, char *argv[]) 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; @@ -321,14 +335,18 @@ int main(int argc, char *argv[]) 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; } } |