From 798cec84dd1783fcbdfb9c077d8682d8ed8b7b21 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Wed, 7 Sep 2016 08:29:34 +0800 Subject: [PATCH] btrfs-progs: receive: introduce option to dump send stream Introduce new option, '--dump' for receive subcommand. With this command, user can dump the metadata of a send stream. Which is quite useful for education purpose or bug reporting. Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- Documentation/btrfs-receive.asciidoc | 15 ++++++++++++++- cmds-receive.c | 35 +++++++++++++++++++++++++++++++---- 2 files changed, 45 insertions(+), 5 deletions(-) diff --git a/Documentation/btrfs-receive.asciidoc b/Documentation/btrfs-receive.asciidoc index e246603..f12e949 100644 --- a/Documentation/btrfs-receive.asciidoc +++ b/Documentation/btrfs-receive.asciidoc @@ -9,12 +9,19 @@ SYNOPSIS -------- *btrfs receive* [options] +or + +*btrfs receive* --dump [options] + DESCRIPTION ----------- Receive a stream of changes and replicate one or more subvolumes that were previously used with *btrfs send* The received subvolumes are stored to -'path'. +'path', if '--dump' option is not given. + +If '--dump' option is given, *btrfs receive* will only do the validation of +the stream, and print the stream metadata. *btrfs receive* will fail int the following cases: @@ -56,6 +63,12 @@ By default the mountpoint is searched in '/proc/self/mounts'. If you do not have '/proc', eg. in a chroot environment, use this option to tell us where this filesystem is mounted. +--dump:: +print the stream metadata ++ +Does not accept the 'path' parameter. So with this option, *btrfs receive* won't +modify your filesystem, and can be run by non-privileged users. + EXIT STATUS ----------- *btrfs receive* returns a zero exit status if it succeeds. Non zero is diff --git a/cmds-receive.c b/cmds-receive.c index 85a6eea..68950b4 100644 --- a/cmds-receive.c +++ b/cmds-receive.c @@ -49,6 +49,7 @@ #include "send.h" #include "send-stream.h" #include "send-utils.h" +#include "send-dump.h" static int g_verbose = 0; @@ -1226,6 +1227,7 @@ int cmd_receive(int argc, char **argv) struct btrfs_receive rctx; int receive_fd = fileno(stdin); u64 max_errors = 1; + int dump = 0; int ret = 0; memset(&rctx, 0, sizeof(rctx)); @@ -1238,9 +1240,11 @@ int cmd_receive(int argc, char **argv) while (1) { int c; + enum { GETOPT_VAL_DUMP = 257 }; static const struct option long_opts[] = { { "max-errors", required_argument, NULL, 'E' }, { "chroot", no_argument, NULL, 'C' }, + { "dump", no_argument, NULL, GETOPT_VAL_DUMP }, { NULL, 0, NULL, 0 } }; @@ -1277,6 +1281,9 @@ int cmd_receive(int argc, char **argv) goto out; } break; + case GETOPT_VAL_DUMP: + dump = 1; + break; case '?': default: error("receive args invalid"); @@ -1284,7 +1291,9 @@ int cmd_receive(int argc, char **argv) } } - if (check_argc_exact(argc - optind, 1)) + if (dump && check_argc_exact(argc - optind, 0)) + usage(cmd_receive_usage); + if (!dump && check_argc_exact(argc - optind, 1)) usage(cmd_receive_usage); tomnt = argv[optind]; @@ -1297,17 +1306,33 @@ int cmd_receive(int argc, char **argv) } } - ret = do_receive(&rctx, tomnt, realmnt, receive_fd, max_errors); + if (dump) { + struct btrfs_dump_send_args dump_args; + + dump_args.root_path[0] = '.'; + dump_args.root_path[1] = '\0'; + dump_args.full_subvol_path[0] = '.'; + dump_args.full_subvol_path[1] = '\0'; + ret = btrfs_read_and_process_send_stream(receive_fd, + &btrfs_print_send_ops, &dump_args, 0, 0); + if (ret < 0) + error("failed to dump the send stream: %s", + strerror(-ret)); + } else { + ret = do_receive(&rctx, tomnt, realmnt, receive_fd, max_errors); + } + if (receive_fd != fileno(stdin)) close(receive_fd); - out: return !!ret; } const char * const cmd_receive_usage[] = { - "btrfs receive [-ve] [-f ] [--max-errors ] ", + "btrfs receive [options] ", + "or", + "btrfs receive --dump [options]", "Receive subvolumes from stdin.", "Receives one or more subvolumes that were previously", "sent with btrfs send. The received subvolumes are stored", @@ -1334,5 +1359,7 @@ const char * const cmd_receive_usage[] = { "-m The root mount point of the destination fs.", " If you do not have /proc use this to tell us where ", " this file system is mounted.", + "--dump Exam and output metadata info of send stream.", + " Don't need parameter.", NULL }; -- 2.7.4