Serge Hallyn reports: "another question: if i run 'restart < out' and sys_restart returns due to a -EPERM on some object, then restart.c returns 1. but if i 'restart --pids', then it reports the error and returns 0. unless i add --copy-status to the flags. that seems inconsistent?"
It was with a subtree checkpoint in a child pidns, root-task is not pid 1, So, the restarts calls ckpt_coordinator_pidns() execution. In commit 2000bbb4b9... "restart: fix race in ckpt_coordinator_pidns and --no-wait" adds a pipe for a coordinator in a new pids to report success/failure of the restart operation back to the parent when the parent does not wish to wait. IOW, the coordinator's exit value is overloaded - used once to report success/failure and once (optionally) to report root-tasks exit status. This patch fixes this by extending the previous commit to make the coordinator-pidns always report the restart status via the pipe, and only use the exit status for --wait --copy-status case. Signed-off-by: Oren Laadan <[email protected]> --- restart.c | 25 ++++++++++++------------- 1 files changed, 12 insertions(+), 13 deletions(-) diff --git a/restart.c b/restart.c index 35c54ea..5871bbf 100644 --- a/restart.c +++ b/restart.c @@ -942,10 +942,12 @@ static int ckpt_coordinator_pidns(struct ckpt_ctx *ctx) ckpt_dbg("forking coordinator in new pidns\n"); /* - * We won't wait for (collect) the coordinator, so we use a - * pipe instead for the coordinator to report success/failure. + * The coordinator report restart susccess/failure via pipe. + * (It cannot use return value, because the in the default + * --wait --copy-status case it is already used to report the + * root-task's return value). */ - if (!ctx->args->wait && pipe(ctx->pipe_coord)) { + if (pipe(ctx->pipe_coord) < 0) { perror("pipe"); return -1; } @@ -981,10 +983,7 @@ static int ckpt_coordinator_pidns(struct ckpt_ctx *ctx) return -1; ctx->args->copy_status = copy; - if (ctx->args->wait) - return ckpt_collect_child(ctx); - else - return ckpt_coordinator_status(ctx); + return ckpt_coordinator_status(ctx); } #else static int ckpt_coordinator_pidns(struct ckpt_ctx *ctx) @@ -1040,13 +1039,13 @@ static int ckpt_coordinator(struct ckpt_ctx *ctx) * around and be reaper until all tasks are gone. * Otherwise, container will die as soon as we exit. */ - if (!ctx->args->wait) { - /* report status because parent won't wait for us */ - if (write(ctx->pipe_coord[1], &ret, sizeof(ret)) < 0) { - perror("failed to report status"); - exit(1); - } + + /* Report success/failure to the parent */ + if (write(ctx->pipe_coord[1], &ret, sizeof(ret)) < 0) { + perror("failed to report status"); + exit(1); } + ret = ckpt_pretend_reaper(ctx); } else if (ctx->args->wait) { ret = ckpt_collect_child(ctx); -- 1.6.0.4 _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
