Introduce new option, '--dump' for receive subcommand.
With this command, user can exam and dump the metadata info of a send
stream.
Which is quite useful for education purpose or bug reporting.
Signed-off-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
---
Documentation/btrfs-receive.asciidoc | 17 +++++++++++++--
cmds-receive.c | 41 ++++++++++++++++++++++++++++++------
2 files changed, 50 insertions(+), 8 deletions(-)
diff --git a/Documentation/btrfs-receive.asciidoc b/Documentation/btrfs-receive.asciidoc
index e246603..e4e3ba4 100644
--- a/Documentation/btrfs-receive.asciidoc
+++ b/Documentation/btrfs-receive.asciidoc
@@ -3,18 +3,25 @@ btrfs-receive(8)
NAME
----
-btrfs-receive - receive subvolumes from send stream
+btrfs-receive - receive/exam subvolumes from send stream
SYNOPSIS
--------
*btrfs receive* [options] <path>
+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 exam the validation of
+the stream, and print the metadata info for debug usage.
*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::
+exam the stream and print metadata info for debug/education purpose.
++
+Does not accept '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 f4a3a4f..32bf086 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;
@@ -1194,6 +1195,7 @@ int cmd_receive(int argc, char **argv)
struct btrfs_receive r;
int receive_fd = fileno(stdin);
u64 max_errors = 1;
+ int dump = 0;
int ret = 0;
memset(&r, 0, sizeof(r));
@@ -1206,9 +1208,11 @@ 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 }
};
@@ -1245,6 +1249,9 @@ int cmd_receive(int argc, char **argv)
goto out;
}
break;
+ case GETOPT_VAL_DUMP:
+ dump = 1;
+ break;
case '?':
default:
error("receive args invalid");
@@ -1252,7 +1259,9 @@ 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];
@@ -1265,19 +1274,37 @@ int cmd_receive(int argc, char **argv)
}
}
- ret = do_receive(&r, tomnt, realmnt, receive_fd, max_errors);
+ if (dump) {
+ struct btrfs_dump_send_args dump_args;
+
+ dump_args.root_path = malloc(PATH_MAX);
+ dump_args.root_path[0] = '.';
+ dump_args.root_path[1] = '\0';
+ dump_args.full_subvol_path = malloc(PATH_MAX);
+ 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(&r, 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 <infile>] [--max-errors <N>] <mount>",
- "Receive subvolumes from stdin.",
- "Receives one or more subvolumes that were previously",
+ "btrfs receive [options] <mount>",
+ "or"
+ "btrfs receive --dump [options]",
+ "Receive/exam subvolumes from stdin.",
+ "Receives/exams one or more subvolumes that were previously",
"sent with btrfs send. The received subvolumes are stored",
"into <mount>.",
"btrfs receive will fail in case a receiving subvolume",
@@ -1302,5 +1329,7 @@ const char * const cmd_receive_usage[] = {
"-m <mountpoint> 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 <mount> parameter.",
NULL
};
--
2.9.3
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