mirror of
https://github.com/torvalds/linux
synced 2024-09-06 18:01:05 +00:00
![Vitaly Kuznetsov](/assets/img/avatar_default.png)
Commitea81fdf098
("Tools: hv: vss: Skip freezing filesystems backed by loop") added skip for filesystems backed by loop device. However, it seems the detection of such cases is incomplete. It was found that with 'devicemapper' storage driver docker creates the following chain: NAME MAJ:MIN loop0 7:0 ..docker-8:4-8473394-pool 253:0 ..docker-8:4-8473394-eac... 253:1 so when we're looking at the mounted device we see major '253' and not '7'. Solve the issue by walking /sys/dev/block/*/slaves chain and checking if there's a loop device somewhere. Other than that, don't skip mountpoints silently when stat() fails. In case e.g. SELinux is failing stat we don't want to skip freezing everything without letting user know about the failure. Fixes:ea81fdf098
("Tools: hv: vss: Skip freezing filesystems backed by loop") Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
338 lines
7.6 KiB
C
338 lines
7.6 KiB
C
/*
|
|
* 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':
|
|
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);
|
|
}
|