If a block device is an LVM logical volume we can resize it using
standard LVM tools.
Add a helper to detect if a device is a DM device. In raw_co_truncate()
check if the block device is DM and resize it executing lvresize.
Signed-off-by: Alexander Ivanov <alexander.iva...@virtuozzo.com>
---
block/file-posix.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 61 insertions(+)
diff --git a/block/file-posix.c b/block/file-posix.c
index 35684f7e21..5f07d98aa5 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -2642,6 +2642,38 @@ raw_regular_truncate(BlockDriverState *bs, int fd,
int64_t offset,
return raw_thread_pool_submit(handle_aiocb_truncate, &acb);
}
+static bool device_is_dm(struct stat *st)
+{
+ unsigned int maj, maj2;
+ char line[32], devname[16];
+ bool ret = false;
+ FILE *f;
+
+ if (!S_ISBLK(st->st_mode)) {
+ return false;
+ }
+
+ f = fopen("/proc/devices", "r");
+ if (!f) {
+ return false;
+ }
+
+ maj = major(st->st_rdev);
+
+ while (fgets(line, sizeof(line), f)) {
+ if (sscanf(line, "%u %15s", &maj2, devname) != 2) {
+ continue;
+ }
+ if (strcmp(devname, "device-mapper") == 0) {
+ ret = (maj == maj2);
+ break;
+ }
+ }
+
+ fclose(f);
+ return ret;
+}
+
static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
bool exact, PreallocMode prealloc,
BdrvRequestFlags flags, Error **errp)
@@ -2670,6 +2702,35 @@ static int coroutine_fn raw_co_truncate(BlockDriverState
*bs, int64_t offset,
if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
int64_t cur_length = raw_getlength(bs);
+ /*
+ * Try to resize an LVM device using LVM tools.
+ */
+ if (device_is_dm(&st) && offset > 0) {
+ int spawn_flags = G_SPAWN_SEARCH_PATH | G_SPAWN_STDOUT_TO_DEV_NULL;
+ int status;
+ bool success;
+ char *err;
+ GError *gerr = NULL;
+ g_autofree char *size_str = g_strdup_printf("%ldB", offset);
+ const char *cmd[] = {"lvresize", "-f", "-L",
+ size_str, bs->filename, NULL};
+
+ success = g_spawn_sync(NULL, (gchar **)cmd, NULL, spawn_flags,
+ NULL, NULL, NULL, &err, &status, &gerr);
+
+ if (success && WEXITSTATUS(status) == 0) {
+ return 0;
+ }
+
+ if (!success) {
+ error_setg(errp, "lvresize execution error: %s",
gerr->message);
+ } else {
+ error_setg(errp, "%s", err);
+ }
+
+ return -EINVAL;
+ }
+
if (offset != cur_length && exact) {
error_setg(errp, "Cannot resize device files");
return -ENOTSUP;
--
2.40.1
