Re: [PATCH 2/4] xfsrestore: fix on-media inventory stream unpacking

[Donald Douwsma <ddouwsma@redhat.com>]

On 14/10/2022 14:37, Donald Douwsma wrote:
> 
> 
> On 14/10/2022 06:05, Darrick J. Wong wrote:
>> On Thu, Oct 13, 2022 at 02:15:16PM +1100, Donald Douwsma wrote:
>>> xfsdump can create multiple streams, when restoring the online inventory
>>> with multiple streams we fail to process these and assert when the
>>> inventory buffer is not fully decoded.
>>>
>>> [root@rhel8 ~]# xfsdump -L "Test1" -f /dev/nst0 -M tape1 -f /dev/nst1 
>>> -M tape2 /boot
>>> xfsdump: using scsi tape (drive_scsitape) strategy
>>> xfsdump: using scsi tape (drive_scsitape) strategy
>>> xfsdump: version 3.1.8 (dump format 3.0) - type ^C for status and 
>>> control
>>> xfsdump: level 0 dump of rhel8:/boot
>>> xfsdump: dump date: Thu Oct  6 13:50:45 2022
>>> xfsdump: session id: aa25fa48-4493-45c7-9027-61e53e486445
>>> xfsdump: session label: "Test1"
>>> xfsdump: ino map phase 1: constructing initial dump list
>>> xfsdump: ino map phase 2: skipping (no pruning necessary)
>>> xfsdump: ino map phase 3: identifying stream starting points
>>> xfsdump: stream 0: ino 133 offset 0 to ino 28839 offset 0
>>> xfsdump: stream 1: ino 28839 offset 0 to end
>>> xfsdump: ino map construction complete
>>> xfsdump: estimated dump size: 328720704 bytes
>>> xfsdump: estimated dump size per stream: 164375728 bytes
>>> xfsdump: /var/lib/xfsdump/inventory created
>>> xfsdump: drive 0: preparing drive
>>> xfsdump: drive 1: preparing drive
>>> xfsdump: drive 1: creating dump session media file 0 (media 0, file 0)
>>> xfsdump: drive 1: dumping ino map
>>> xfsdump: drive 1: dumping non-directory files
>>> xfsdump: drive 0: creating dump session media file 0 (media 0, file 0)
>>> xfsdump: drive 0: dumping ino map
>>> xfsdump: drive 0: dumping directories
>>> xfsdump: drive 0: dumping non-directory files
>>> xfsdump: drive 1: ending media file
>>> xfsdump: drive 1: media file size 166723584 bytes
>>> xfsdump: drive 1: waiting for synchronized session inventory dump
>>> xfsdump: drive 0: ending media file
>>> xfsdump: drive 0: media file size 165675008 bytes
>>> xfsdump: drive 0: waiting for synchronized session inventory dump
>>> xfsdump: drive 0: dumping session inventory
>>> xfsdump: drive 0: beginning inventory media file
>>> xfsdump: drive 0: media file 1 (media 0, file 1)
>>> xfsdump: drive 0: ending inventory media file
>>> xfsdump: drive 0: inventory media file size 2097152 bytes
>>> xfsdump: drive 0: writing stream terminator
>>> xfsdump: drive 0: beginning media stream terminator
>>> xfsdump: drive 0: media file 2 (media 0, file 2)
>>> xfsdump: drive 0: ending media stream terminator
>>> xfsdump: drive 0: media stream terminator size 1048576 bytes
>>> xfsdump: drive 1: dumping session inventory
>>> xfsdump: drive 1: beginning inventory media file
>>> xfsdump: drive 1: media file 1 (media 0, file 1)
>>> xfsdump: drive 1: ending inventory media file
>>> xfsdump: drive 1: inventory media file size 2097152 bytes
>>> xfsdump: drive 1: writing stream terminator
>>> xfsdump: drive 1: beginning media stream terminator
>>> xfsdump: drive 1: media file 2 (media 0, file 2)
>>> xfsdump: drive 1: ending media stream terminator
>>> xfsdump: drive 1: media stream terminator size 1048576 bytes
>>> xfsdump: dump size (non-dir files) : 328189016 bytes
>>> xfsdump: dump complete: 4 seconds elapsed
>>> xfsdump: Dump Summary:
>>> xfsdump:   stream 0 /dev/nst0 OK (success)
>>> xfsdump:   stream 1 /dev/nst1 OK (success)
>>> xfsdump: Dump Status: SUCCESS
>>> [root@rhel8 ~]# xfsdump -I
>>> file system 0:
>>>     fs id:        26dd5aa0-b901-4cf5-9b68-0c5753cb3ab8
>>>     session 0:
>>>         mount point:    rhel8:/boot
>>>         device:        rhel8:/dev/sda1
>>>         time:        Thu Oct  6 13:50:45 2022
>>>         session label:    "Test1"
>>>         session id:    aa25fa48-4493-45c7-9027-61e53e486445
>>>         level:        0
>>>         resumed:    NO
>>>         subtree:    NO
>>>         streams:    2
>>>         stream 0:
>>>             pathname:    /dev/nst0
>>>             start:        ino 133 offset 0
>>>             end:        ino 28839 offset 0
>>>             interrupted:    NO
>>>             media files:    2
>>>             media file 0:
>>>                 mfile index:    0
>>>                 mfile type:    data
>>>                 mfile size:    165675008
>>>                 mfile start:    ino 133 offset 0
>>>                 mfile end:    ino 28839 offset 0
>>>                 media label:    "tape1"
>>>                 media id:    adb31f2a-f026-4597-a20a-326f28ecbaf1
>>>             media file 1:
>>>                 mfile index:    1
>>>                 mfile type:    inventory
>>>                 mfile size:    2097152
>>>                 media label:    "tape1"
>>>                 media id:    adb31f2a-f026-4597-a20a-326f28ecbaf1
>>>         stream 1:
>>>             pathname:    /dev/nst1
>>>             start:        ino 28839 offset 0
>>>             end:        ino 1572997 offset 0
>>>             interrupted:    NO
>>>             media files:    2
>>>             media file 0:
>>>                 mfile index:    0
>>>                 mfile type:    data
>>>                 mfile size:    166723584
>>>                 mfile start:    ino 28839 offset 0
>>>                 mfile end:    ino 1572997 offset 0
>>>                 media label:    "tape2"
>>>                 media id:    22224f02-b6c7-47d5-ad61-a61ba071c8a8
>>>             media file 1:
>>>                 mfile index:    1
>>>                 mfile type:    inventory
>>>                 mfile size:    2097152
>>>                 media label:    "tape2"
>>>                 media id:    22224f02-b6c7-47d5-ad61-a61ba071c8a8
>>> xfsdump: Dump Status: SUCCESS
>>> [root@rhel8 ~]# mv /var/lib/xfsdump/inventory 
>>> /var/lib/xfsdump/inventory_two_sessions
>>> [root@rhel8 ~]# xfsdump -I
>>> xfsdump: Dump Status: SUCCESS
>>>
>>> [root@rhel8 ~]# xfsrestore -L Test1 -f /dev/nst0 /tmp/test1/
>>> xfsrestore: using scsi tape (drive_scsitape) strategy
>>> xfsrestore: version 3.1.8 (dump format 3.0) - type ^C for status and 
>>> control
>>> xfsrestore: searching media for dump
>>> xfsrestore: preparing drive
>>> xfsrestore: examining media file 2
>>> xfsrestore: found dump matching specified label:
>>> xfsrestore: hostname: rhel8
>>> xfsrestore: mount point: /boot
>>> xfsrestore: volume: /dev/sda1
>>> xfsrestore: session time: Thu Oct  6 13:50:45 2022
>>> xfsrestore: level: 0
>>> xfsrestore: session label: "Test1"
>>> xfsrestore: media label: "tape1"
>>> xfsrestore: file system id: 26dd5aa0-b901-4cf5-9b68-0c5753cb3ab8
>>> xfsrestore: session id: aa25fa48-4493-45c7-9027-61e53e486445
>>> xfsrestore: media id: adb31f2a-f026-4597-a20a-326f28ecbaf1
>>> xfsrestore: searching media for directory dump
>>> xfsrestore: rewinding
>>> xfsrestore: examining media file 0
>>> xfsrestore: reading directories
>>> xfsrestore: 9 directories and 320 entries processed
>>> xfsrestore: directory post-processing
>>> xfsrestore: restoring non-directory files
>>> xfsrestore: examining media file 1
>>> xfsrestore: inv_stobj.c:1119: stobj_unpack_sessinfo: Assertion 
>>> `(size_t) ( p - (char *) bufp ) == bufsz' failed.
>>> Aborted (core dumped)
>>>
>>> Make sure we unpack multiple streams when restoring the online
>>> inventory from media.
>>>
>>> Signed-off-by: Donald Douwsma <ddouwsma@redhat.com>
>>
>> Much better now, though I hope there's an fstest coming to make sure
>> that multistream restore/dump work properly.
> 
> That could be a little tricky.
> 
> xfstests currently only supports one TAPE_DEV (and a remote
> RMT_TAPE_DEV). So we'd need to add support for multiple tapes,
> something like

Thinking about this some more RMT_TAPE_DEV may be ok. If streaming to
multiple targets is meant to enable an offsite dump it could be done
via remote i.e.

# xfsdump -L "Test3" -f /dev/nst0 -M "tape1" -f 
backup.example.com:/dev/nst0 -M "tape2" /

The existing remote tests xfs/037 and xfs/038 just use the device for a 
simple backup.

Or I could be inventing a never useful use case.

Don

> 
> TAPE_DEV1=/dev/nst0
> TAPE_DEV2=/dev/nst1
> 
> Then it can be hard to get access to a tape drive, let alone two.
> 
> Probably the easiest way to address that is to provide instructions on
> how to setup mhvtl, https://github.com/markh794/mhvtl and load the
> tapes before a test run with
> 
> [root@rhel8 ~]# systemctl start mhvtl.target
> [root@rhel8 ~]# mtx -f /dev/sch0 load 1 0; mtx -f /dev/sch load 2 1
> Loading media from Storage Element 1 into drive 0...done
> Loading media from Storage Element 2 into drive 1...done
> [root@rhel8 ~]# ./check -g xfs/tape
> 
> Not sure there's many people who test the tape group, so this may be
> generally useful.
> 
> mhvtl requires a kernel module to be built, not sure if that would
> bother QE folk when doing general tests, but for xfsdump userspace
> testing it should be fine.
> 
> Don
> 
> 
>> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
>>
>> --D
>>
>>> ---
>>>   inventory/inv_stobj.c | 13 +++++++------
>>>   1 file changed, 7 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/inventory/inv_stobj.c b/inventory/inv_stobj.c
>>> index b461666..025d431 100644
>>> --- a/inventory/inv_stobj.c
>>> +++ b/inventory/inv_stobj.c
>>> @@ -1065,25 +1065,26 @@ stobj_unpack_sessinfo(
>>>           return BOOL_FALSE;
>>>       }
>>> +    /* get the seshdr and then, the remainder of the session */
>>>       xlate_invt_seshdr((invt_seshdr_t *)p, (invt_seshdr_t *)tmpbuf, 1);
>>>       bcopy(tmpbuf, p, sizeof(invt_seshdr_t));
>>> -
>>> -    /* get the seshdr and then, the remainder of the session */
>>>       s->seshdr = (invt_seshdr_t *)p;
>>>       s->seshdr->sh_sess_off = -1;
>>>       p += sizeof(invt_seshdr_t);
>>> -
>>>       xlate_invt_session((invt_session_t *)p, (invt_session_t 
>>> *)tmpbuf, 1);
>>>       bcopy (tmpbuf, p, sizeof(invt_session_t));
>>>       s->ses = (invt_session_t *)p;
>>>       p += sizeof(invt_session_t);
>>>       /* the array of all the streams belonging to this session */
>>> -    xlate_invt_stream((invt_stream_t *)p, (invt_stream_t *)tmpbuf, 1);
>>> -    bcopy(tmpbuf, p, sizeof(invt_stream_t));
>>>       s->strms = (invt_stream_t *)p;
>>> -    p += s->ses->s_cur_nstreams * sizeof(invt_stream_t);
>>> +    for (i = 0; i < s->ses->s_cur_nstreams; i++) {
>>> +        xlate_invt_stream((invt_stream_t *)p,
>>> +                  (invt_stream_t *)tmpbuf, 1);
>>> +        bcopy(tmpbuf, p, sizeof(invt_stream_t));
>>> +        p += sizeof(invt_stream_t);
>>> +    }
>>>       /* all the media files */
>>>       s->mfiles = (invt_mediafile_t *)p;
>>> -- 
>>> 2.31.1
>>>
>>