On 6/21/17 3:34 PM, Darrick J. Wong wrote:
> On Wed, Jun 21, 2017 at 02:18:23PM -0500, Eric Sandeen wrote:
>> On 5/26/17 11:13 AM, Eric Sandeen wrote:
>>> After the long discussion about warning the user and/or consumer
>>> of xfs_metadumps about dirty logs, it crossed my mind that we
>>> could use the reserved slot in the metadump header to tag the
>>> file with attributes, so the consumer of the metadump knows how
>>> it was created.
>>>
>>> This patch adds 4 flags to describe the metadump: The first simply
>>> indicates the presence of any (or no) informational flags.
>>> The old mb_reserved field has been 0 on disk since inception, so
>>> the presence of XFS_METADUMP_INFO_FLAGS indicates that this metadump
>>> may contain the informational flags:
>>>
>>> - dirty log
>>> - obfuscated
>>> - full blocks (unused portions of metadata blocks
>>> are not zeroed out).
>>>
>>> It then adds a new option to xfs_mdrestore, "-i" to show info,
>>> which can be used with or without a target file:
>>>
>>> # xfs_mdrestore -i metadumpfile
>>> metadumpfile: not obfuscated, clean log, full metadata blocks
>>>
>>> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
>>> ---
>>>
>>> V2: rename to mb_info, add the "we have flags" flag
>>
>> Ping, any thoughts on this V2?
>
> /me wonder if show_info mode ought to complain if we see an "obviously"
> bogus value (flags are set but XFS_METADUMP_INFO_FLAGS is clear, flags
> we don't know about are set) and dump the raw hex value...
well, it's been memset to 0 since inception. Sure, something could have
gone wrong in transit, or whatever, I guess...
I guess it might be nice to sanity check it, but to avoid another
round trip:
> ...but on the other hand it's redefining a probably-zero field in a
> semi-ephemeral data file format to be an optional informational field,
> so maybe it's good enough.
>
> Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
thanks,
-Eric
> --D
>
>>
>>> diff --git a/db/metadump.c b/db/metadump.c
>>> index fe068ef..2f5b5b5 100644
>>> --- a/db/metadump.c
>>> +++ b/db/metadump.c
>>> @@ -2820,6 +2820,28 @@ metadump_f(
>>> metablock->mb_blocklog = BBSHIFT;
>>> metablock->mb_magic = cpu_to_be32(XFS_MD_MAGIC);
>>>
>>> + /* Set flags about state of metadump */
>>> + metablock->mb_info = XFS_METADUMP_INFO_FLAGS;
>>> + if (obfuscate)
>>> + metablock->mb_info |= XFS_METADUMP_OBFUSCATED;
>>> + if (!zero_stale_data)
>>> + metablock->mb_info |= XFS_METADUMP_FULLBLOCKS;
>>> +
>>> + /* If we'll copy the log, see if the log is dirty */
>>> + if (mp->m_sb.sb_logstart) {
>>> + push_cur();
>>> + set_cur(&typtab[TYP_LOG],
>>> + XFS_FSB_TO_DADDR(mp, mp->m_sb.sb_logstart),
>>> + mp->m_sb.sb_logblocks * blkbb, DB_RING_IGN, NULL);
>>> + if (iocur_top->data) { /* best effort */
>>> + struct xlog log;
>>> +
>>> + if (xlog_is_dirty(mp, &log, &x, 0))
>>> + metablock->mb_info |= XFS_METADUMP_DIRTYLOG;
>>> + }
>>> + pop_cur();
>>> + }
>>> +
>>> block_index = (__be64 *)((char *)metablock + sizeof(xfs_metablock_t));
>>> block_buffer = (char *)metablock + BBSIZE;
>>> num_indices = (BBSIZE - sizeof(xfs_metablock_t)) / sizeof(__be64);
>>> diff --git a/include/xfs_metadump.h b/include/xfs_metadump.h
>>> index f4be51b..7f3039e 100644
>>> --- a/include/xfs_metadump.h
>>> +++ b/include/xfs_metadump.h
>>> @@ -25,8 +25,14 @@ typedef struct xfs_metablock {
>>> __be32 mb_magic;
>>> __be16 mb_count;
>>> __uint8_t mb_blocklog;
>>> - __uint8_t mb_reserved;
>>> + __uint8_t mb_info;
>>> /* followed by an array of xfs_daddr_t */
>>> } xfs_metablock_t;
>>>
>>> +/* These flags are informational only, not backwards compatible */
>>> +#define XFS_METADUMP_INFO_FLAGS (1 << 0) /* This image has informative flags */
>>> +#define XFS_METADUMP_OBFUSCATED (1 << 1)
>>> +#define XFS_METADUMP_FULLBLOCKS (1 << 2)
>>> +#define XFS_METADUMP_DIRTYLOG (1 << 3)
>>> +
>>> #endif /* _XFS_METADUMP_H_ */
>>> diff --git a/man/man8/xfs_mdrestore.8 b/man/man8/xfs_mdrestore.8
>>> index 2095f15..72f3b29 100644
>>> --- a/man/man8/xfs_mdrestore.8
>>> +++ b/man/man8/xfs_mdrestore.8
>>> @@ -4,11 +4,15 @@ xfs_mdrestore \- restores an XFS metadump image to a filesystem image
>>> .SH SYNOPSIS
>>> .B xfs_mdrestore
>>> [
>>> -.B \-g
>>> +.B \-gi
>>> ]
>>> .I source
>>> .I target
>>> .br
>>> +.B xfs_mdrestore
>>> +.B \-i
>>> +.I source
>>> +.br
>>> .B xfs_mdrestore \-V
>>> .SH DESCRIPTION
>>> .B xfs_mdrestore
>>> @@ -39,6 +43,12 @@ can be destroyed.
>>> .B \-g
>>> Shows restore progress on stdout.
>>> .TP
>>> +.B \-i
>>> +Shows metadump information on stdout. If no
>>> +.I target
>>> +is specified, exits after displaying information. Older metadumps man not
>>> +include any descriptive information.
>>> +.TP
>>> .B \-V
>>> Prints the version number and exits.
>>> .SH DIAGNOSTICS
>>> diff --git a/mdrestore/xfs_mdrestore.c b/mdrestore/xfs_mdrestore.c
>>> index 0d399f1..9d1b4e8 100644
>>> --- a/mdrestore/xfs_mdrestore.c
>>> +++ b/mdrestore/xfs_mdrestore.c
>>> @@ -21,6 +21,7 @@
>>>
>>> char *progname;
>>> int show_progress = 0;
>>> +int show_info = 0;
>>> int progress_since_warning = 0;
>>>
>>> static void
>>> @@ -213,11 +214,14 @@ main(
>>>
>>> progname = basename(argv[0]);
>>>
>>> - while ((c = getopt(argc, argv, "gV")) != EOF) {
>>> + while ((c = getopt(argc, argv, "giV")) != EOF) {
>>> switch (c) {
>>> case 'g':
>>> show_progress = 1;
>>> break;
>>> + case 'i':
>>> + show_info = 1;
>>> + break;
>>> case 'V':
>>> printf("%s version %s\n", progname, VERSION);
>>> exit(0);
>>> @@ -226,7 +230,11 @@ main(
>>> }
>>> }
>>>
>>> - if (argc - optind != 2)
>>> + if (argc - optind < 1 || argc - optind > 2)
>>> + usage();
>>> +
>>> + /* show_info without a target is ok */
>>> + if (!show_info && argc - optind != 2)
>>> usage();
>>>
>>> /* open source */
>>> @@ -239,6 +247,34 @@ main(
>>> if (src_f == NULL)
>>> fatal("cannot open source dump file\n");
>>> }
>>> +
>>> + if (show_info) {
>>> + xfs_metablock_t mb;
>>> +
>>> + if (fread(&mb, sizeof(mb), 1, src_f) != 1)
>>> + fatal("error reading from file: %s\n", strerror(errno));
>>> +
>>> + if (be32_to_cpu(mb.mb_magic) != XFS_MD_MAGIC)
>>> + fatal("specified file is not a metadata dump\n");
>>> +
>>> + if (mb.mb_info & XFS_METADUMP_INFO_FLAGS) {
>>> + printf("%s: %sobfuscated, %s log, %s metadata blocks\n",
>>> + argv[optind],
>>> + mb.mb_info & XFS_METADUMP_OBFUSCATED ? "":"not ",
>>> + mb.mb_info & XFS_METADUMP_DIRTYLOG ? "dirty":"clean",
>>> + mb.mb_info & XFS_METADUMP_FULLBLOCKS ? "full":"zeroed");
>>> + } else {
>>> + printf("%s: no informational flags present\n",
>>> + argv[optind]);
>>> + }
>>> +
>>> + if (argc - optind == 1)
>>> + exit(0);
>>> +
>>> + /* Go back to the beginning for the restore function */
>>> + fseek(src_f, 0L, SEEK_SET);
>>> + }
>>> +
>>> optind++;
>>>
>>> /* check and open target */
>>>
>>> --
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