On Thu, May 25, 2023 at 07:13:03PM +0530, Chandan Babu R wrote:
> On Tue, May 23, 2023 at 11:09:59 AM -0700, Darrick J. Wong wrote:
> > On Tue, May 23, 2023 at 02:30:49PM +0530, Chandan Babu R wrote:
> >> metadump v2 format allows dumping metadata from external log devices. This
> >> commit allows passing the device file to which log data must be restored from
> >> the corresponding metadump file.
> >>
> >> Signed-off-by: Chandan Babu R <chandan.babu@xxxxxxxxxx>
> >> ---
> >> mdrestore/xfs_mdrestore.c | 10 ++++++++--
> >> 1 file changed, 8 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/mdrestore/xfs_mdrestore.c b/mdrestore/xfs_mdrestore.c
> >> index 9e06d37dc..f5eff62ef 100644
> >> --- a/mdrestore/xfs_mdrestore.c
> >> +++ b/mdrestore/xfs_mdrestore.c
> >> @@ -427,7 +427,8 @@ static struct mdrestore_ops mdrestore_ops_v2 = {
> >> static void
> >> usage(void)
> >> {
> >> - fprintf(stderr, "Usage: %s [-V] [-g] [-i] source target\n", progname);
> >> + fprintf(stderr, "Usage: %s [-V] [-g] [-i] [-l logdev] source target\n",
> >> + progname);
> >> exit(1);
> >> }
> >>
> >> @@ -453,7 +454,7 @@ main(
> >>
> >> progname = basename(argv[0]);
> >>
> >> - while ((c = getopt(argc, argv, "giV")) != EOF) {
> >> + while ((c = getopt(argc, argv, "gil:V")) != EOF) {
> >> switch (c) {
> >> case 'g':
> >> mdrestore.show_progress = 1;
> >> @@ -461,6 +462,9 @@ main(
> >> case 'i':
> >> mdrestore.show_info = 1;
> >> break;
> >> + case 'l':
> >> + logdev = optarg;
> >> + break;
> >> case 'V':
> >> printf("%s version %s\n", progname, VERSION);
> >> exit(0);
> >> @@ -493,6 +497,8 @@ main(
> >> }
> >>
> >> if (mdrestore_ops_v1.read_header(&mb, src_f) == 0) {
> >> + if (logdev != NULL)
> >> + usage();
> >> mdrestore.mdrops = &mdrestore_ops_v1;
> >> header = &mb;
> >> } else if (mdrestore_ops_v2.read_header(&xmh, src_f) == 0) {
> >
> > What if we have a v2 with XME_ADDR_LOG_DEVICE meta_extents but the
> > caller doesn't specify -l? Do we proceed with the metadump, only to
> > fail midway through the restore?
>
> restore_v2() has the following statement just after reading in the superblock,
>
> if (sb.sb_logstart == 0 && log_fd == -1)
> fatal("External Log device is required\n");
>
> Hence, In the case of a missing log device argument, the program exits before
> any metadata is written to the target device.
Ah, ok, that's how you handle that. In that case the only reason for a
flag in the v2 metadump header would be the principle of declaring
things that happen later in the metadump stream/file. Your call. :)
--D
> --
> chandan
