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-rw-r--r--tools/hv/hv_vss_daemon.c48
1 files changed, 40 insertions, 8 deletions
diff --git a/tools/hv/hv_vss_daemon.c b/tools/hv/hv_vss_daemon.c
index 6a213b8cd7b9..1db9430d3fe4 100644
--- a/tools/hv/hv_vss_daemon.c
+++ b/tools/hv/hv_vss_daemon.c
@@ -44,21 +44,39 @@ 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;
@@ -68,11 +86,9 @@ static int vss_operate(int operation)
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;
@@ -93,15 +109,23 @@ 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;
}
return error;
+err:
+ endmntent(mounts);
+ vss_operate(VSS_OP_THAW);
+ return error;
}
static int netlink_send(int fd, struct cn_msg *msg)
@@ -249,8 +273,16 @@ 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);