ping 2 On 3/15/24 09:58, Alexander Ivanov wrote:
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..af17a43fe9 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, *gerr_exit = NULL; + g_autofree char *size_str = g_strdup_printf("%" PRId64 "B", 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 && g_spawn_check_exit_status(status, &gerr_exit)) { + return 0; + } + + if (success) { + error_setg(errp, "%s: %s", gerr_exit->message, err); + } else { + error_setg(errp, "lvresize execution error: %s", gerr->message); + } + + return -EINVAL; + } + if (offset != cur_length && exact) { error_setg(errp, "Cannot resize device files"); return -ENOTSUP;
-- Best regards, Alexander Ivanov
