Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 339 insertions, 0 deletions

diff --git a/tools/hv/hv_vss_daemon.c b/tools/hv/hv_vss_daemon.c
new file mode 100644
index 000000000..c2bb8a360
--- /dev/null
+++ b/tools/hv/hv_vss_daemon.c
@@ -0,0 +1,339 @@
+/*
+ * 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.
+ *
+ */
+
+
+#include <sys/types.h>
+#include <sys/poll.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <mntent.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <ctype.h>
+#include <errno.h>
+#include <linux/fs.h>
+#include <linux/major.h>
+#include <linux/hyperv.h>
+#include <syslog.h>
+#include <getopt.h>
+#include <stdbool.h>
+#include <dirent.h>
+
+/* Don't use syslog() in the function since that can cause write to disk */
+static int vss_do_freeze(char *dir, unsigned int cmd)
+{
+	int ret, fd = open(dir, O_RDONLY);
+
+	if (fd < 0)
+		return 1;
+
+	ret = ioctl(fd, cmd, 0);
+
+	/*
+	 * 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
+	 *  by mistake or on purpose;
+	 * 2) The subvolume of btrfs appears to have the same partition
+	 * mounted more than once.
+	 */
+	if (ret) {
+		if ((cmd == FIFREEZE && errno == EBUSY) ||
+		    (cmd == FITHAW && errno == EINVAL)) {
+			close(fd);
+			return 0;
+		}
+	}
+
+	close(fd);
+	return !!ret;
+}
+
+static bool is_dev_loop(const char *blkname)
+{
+	char *buffer;
+	DIR *dir;
+	struct dirent *entry;
+	bool ret = false;
+
+	buffer = malloc(PATH_MAX);
+	if (!buffer) {
+		syslog(LOG_ERR, "Can't allocate memory!");
+		exit(1);
+	}
+
+	snprintf(buffer, PATH_MAX, "%s/loop", blkname);
+	if (!access(buffer, R_OK | X_OK)) {
+		ret = true;
+		goto free_buffer;
+	} else if (errno != ENOENT) {
+		syslog(LOG_ERR, "Can't access: %s; error:%d %s!",
+		       buffer, errno, strerror(errno));
+	}
+
+	snprintf(buffer, PATH_MAX, "%s/slaves", blkname);
+	dir = opendir(buffer);
+	if (!dir) {
+		if (errno != ENOENT)
+			syslog(LOG_ERR, "Can't opendir: %s; error:%d %s!",
+			       buffer, errno, strerror(errno));
+		goto free_buffer;
+	}
+
+	while ((entry = readdir(dir)) != NULL) {
+		if (strcmp(entry->d_name, ".") == 0 ||
+		    strcmp(entry->d_name, "..") == 0)
+			continue;
+
+		snprintf(buffer, PATH_MAX, "%s/slaves/%s", blkname,
+			 entry->d_name);
+		if (is_dev_loop(buffer)) {
+			ret = true;
+			break;
+		}
+	}
+	closedir(dir);
+free_buffer:
+	free(buffer);
+	return ret;
+}
+
+static int vss_operate(int operation)
+{
+	char match[] = "/dev/";
+	FILE *mounts;
+	struct mntent *ent;
+	struct stat sb;
+	char errdir[1024] = {0};
+	char blkdir[23]; /* /sys/dev/block/XXX:XXX */
+	unsigned int cmd;
+	int error = 0, root_seen = 0, save_errno = 0;
+
+	switch (operation) {
+	case VSS_OP_FREEZE:
+		cmd = FIFREEZE;
+		break;
+	case VSS_OP_THAW:
+		cmd = FITHAW;
+		break;
+	default:
+		return -1;
+	}
+
+	mounts = setmntent("/proc/mounts", "r");
+	if (mounts == NULL)
+		return -1;
+
+	while ((ent = getmntent(mounts))) {
+		if (strncmp(ent->mnt_fsname, match, strlen(match)))
+			continue;
+		if (stat(ent->mnt_fsname, &sb)) {
+			syslog(LOG_ERR, "Can't stat: %s; error:%d %s!",
+			       ent->mnt_fsname, errno, strerror(errno));
+		} else {
+			sprintf(blkdir, "/sys/dev/block/%d:%d",
+				major(sb.st_rdev), minor(sb.st_rdev));
+			if (is_dev_loop(blkdir))
+				continue;
+		}
+		if (hasmntopt(ent, MNTOPT_RO) != NULL)
+			continue;
+		if (strcmp(ent->mnt_type, "vfat") == 0)
+			continue;
+		if (strcmp(ent->mnt_dir, "/") == 0) {
+			root_seen = 1;
+			continue;
+		}
+		error |= vss_do_freeze(ent->mnt_dir, cmd);
+		if (error && operation == VSS_OP_FREEZE)
+			goto err;
+	}
+
+	endmntent(mounts);
+
+	if (root_seen) {
+		error |= vss_do_freeze("/", cmd);
+		if (error && operation == VSS_OP_FREEZE)
+			goto err;
+	}
+
+	goto out;
+err:
+	save_errno = errno;
+	if (ent) {
+		strncpy(errdir, ent->mnt_dir, sizeof(errdir)-1);
+		endmntent(mounts);
+	}
+	vss_operate(VSS_OP_THAW);
+	/* Call syslog after we thaw all filesystems */
+	if (ent)
+		syslog(LOG_ERR, "FREEZE of %s failed; error:%d %s",
+		       errdir, save_errno, strerror(save_errno));
+	else
+		syslog(LOG_ERR, "FREEZE of / failed; error:%d %s", save_errno,
+		       strerror(save_errno));
+out:
+	return error;
+}
+
+void print_usage(char *argv[])
+{
+	fprintf(stderr, "Usage: %s [options]\n"
+		"Options are:\n"
+		"  -n, --no-daemon        stay in foreground, don't daemonize\n"
+		"  -h, --help             print this help\n", argv[0]);
+}
+
+int main(int argc, char *argv[])
+{
+	int vss_fd, 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;
+	__u32 kernel_modver;
+
+	static struct option long_options[] = {
+		{"help",	no_argument,	   0,  'h' },
+		{"no-daemon",	no_argument,	   0,  'n' },
+		{0,		0,		   0,  0   }
+	};
+
+	while ((opt = getopt_long(argc, argv, "hn", long_options,
+				  &long_index)) != -1) {
+		switch (opt) {
+		case 'n':
+			daemonize = 0;
+			break;
+		case 'h':
+			print_usage(argv);
+			exit(0);
+		default:
+			print_usage(argv);
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	if (daemonize && daemon(1, 0))
+		return 1;
+
+	openlog("Hyper-V VSS", 0, LOG_USER);
+	syslog(LOG_INFO, "VSS starting; pid is:%d", getpid());
+
+	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",
+		       errno, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+	/*
+	 * Register ourselves with the kernel.
+	 */
+	vss_msg->vss_hdr.operation = VSS_OP_REGISTER1;
+
+	len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
+	if (len < 0) {
+		syslog(LOG_ERR, "registration to kernel failed; error: %d %s",
+		       errno, strerror(errno));
+		close(vss_fd);
+		exit(EXIT_FAILURE);
+	}
+
+	pfd.fd = vss_fd;
+
+	while (1) {
+		pfd.events = POLLIN;
+		pfd.revents = 0;
+
+		if (poll(&pfd, 1, -1) < 0) {
+			syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno));
+			if (errno == EINVAL) {
+				close(vss_fd);
+				exit(EXIT_FAILURE);
+			}
+			else
+				continue;
+		}
+
+		len = read(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
+
+		if (in_handshake) {
+			if (len != sizeof(kernel_modver)) {
+				syslog(LOG_ERR, "invalid version negotiation");
+				exit(EXIT_FAILURE);
+			}
+			kernel_modver = *(__u32 *)vss_msg;
+			in_handshake = 0;
+			syslog(LOG_INFO, "VSS: kernel module version: %d",
+			       kernel_modver);
+			continue;
+		}
+
+		if (len != sizeof(struct hv_vss_msg)) {
+			syslog(LOG_ERR, "read failed; error:%d %s",
+			       errno, strerror(errno));
+			close(vss_fd);
+			return EXIT_FAILURE;
+		}
+
+		op = vss_msg->vss_hdr.operation;
+		error =  HV_S_OK;
+
+		switch (op) {
+		case VSS_OP_FREEZE:
+		case VSS_OP_THAW:
+			error = vss_operate(op);
+			syslog(LOG_INFO, "VSS: op=%s: %s\n",
+				op == VSS_OP_FREEZE ? "FREEZE" : "THAW",
+				error ? "failed" : "succeeded");
+
+			if (error) {
+				error = HV_E_FAIL;
+				syslog(LOG_ERR, "op=%d failed!", op);
+				syslog(LOG_ERR, "report it with these files:");
+				syslog(LOG_ERR, "/etc/fstab and /proc/mounts");
+			}
+			break;
+		case VSS_OP_HOT_BACKUP:
+			syslog(LOG_INFO, "VSS: op=CHECK HOT BACKUP\n");
+			break;
+		default:
+			syslog(LOG_ERR, "Illegal op:%d\n", op);
+		}
+		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);
+		}
+	}
+
+	close(vss_fd);
+	exit(0);
+}