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Diffstat (limited to 'tools/hv/hv_vss_daemon.c')
-rw-r--r--tools/hv/hv_vss_daemon.c95
1 files changed, 82 insertions, 13 deletions
diff --git a/tools/hv/hv_vss_daemon.c b/tools/hv/hv_vss_daemon.c
index 6a213b8cd7b9..5e63f70bd956 100644
--- a/tools/hv/hv_vss_daemon.c
+++ b/tools/hv/hv_vss_daemon.c
@@ -36,6 +36,7 @@
#include <linux/hyperv.h>
#include <linux/netlink.h>
#include <syslog.h>
+#include <getopt.h>
static struct sockaddr_nl addr;
@@ -44,35 +45,51 @@ static struct sockaddr_nl addr;
#endif
-static int vss_do_freeze(char *dir, unsigned int cmd, char *fs_op)
+/* 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);
- syslog(LOG_INFO, "VSS: %s of %s: %s\n", fs_op, dir, strerror(errno));
+
+ /*
+ * 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 int vss_operate(int operation)
{
- char *fs_op;
char match[] = "/dev/";
FILE *mounts;
struct mntent *ent;
unsigned int cmd;
- int error = 0, root_seen = 0;
+ int error = 0, root_seen = 0, save_errno = 0;
switch (operation) {
case VSS_OP_FREEZE:
cmd = FIFREEZE;
- fs_op = "freeze";
break;
case VSS_OP_THAW:
cmd = FITHAW;
- fs_op = "thaw";
break;
default:
return -1;
@@ -85,7 +102,7 @@ static int vss_operate(int operation)
while ((ent = getmntent(mounts))) {
if (strncmp(ent->mnt_fsname, match, strlen(match)))
continue;
- if (strcmp(ent->mnt_type, "iso9660") == 0)
+ if (hasmntopt(ent, MNTOPT_RO) != NULL)
continue;
if (strcmp(ent->mnt_type, "vfat") == 0)
continue;
@@ -93,14 +110,30 @@ static int vss_operate(int operation)
root_seen = 1;
continue;
}
- error |= vss_do_freeze(ent->mnt_dir, cmd, fs_op);
+ 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, fs_op);
+ error |= vss_do_freeze("/", cmd);
+ if (error && operation == VSS_OP_FREEZE)
+ goto err;
}
+ goto out;
+err:
+ save_errno = errno;
+ vss_operate(VSS_OP_THAW);
+ /* Call syslog after we thaw all filesystems */
+ if (ent)
+ syslog(LOG_ERR, "FREEZE of %s failed; error:%d %s",
+ ent->mnt_dir, save_errno, strerror(save_errno));
+ else
+ syslog(LOG_ERR, "FREEZE of / failed; error:%d %s", save_errno,
+ strerror(save_errno));
+out:
+ endmntent(mounts);
return error;
}
@@ -131,7 +164,15 @@ static int netlink_send(int fd, struct cn_msg *msg)
return sendmsg(fd, &message, 0);
}
-int main(void)
+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 fd, len, nl_group;
int error;
@@ -143,8 +184,28 @@ int main(void)
struct hv_vss_msg *vss_msg;
char *vss_recv_buffer;
size_t vss_recv_buffer_len;
+ int daemonize = 1, long_index = 0, opt;
+
+ 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 (daemon(1, 0))
+ if (daemonize && daemon(1, 0))
return 1;
openlog("Hyper-V VSS", 0, LOG_USER);
@@ -249,8 +310,16 @@ int main(void)
case VSS_OP_FREEZE:
case VSS_OP_THAW:
error = vss_operate(op);
- if (error)
+ 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;
default:
syslog(LOG_ERR, "Illegal op:%d\n", op);