zdb: add support for object ranges for zdb -d

Allow a range of object identifiers to dump with -d. This may
be useful when dumping a large dataset and you want to break
it up into multiple phases, or to resume where a previous scan
left off. Object type selection flags are supported to reduce
the performance overhead of verbosely dumping unwanted objects,
and to reduce the amount of post-processing work needed to
filter out unwanted objects from zdb output.

This change extends existing syntax in a backward-compatible
way. That is, the base case of a range is to specify a single
object identifier to dump. Ranges and object identifiers can
be intermixed as command line parameters.

Usage synopsis:

    Object ranges take the form <start>:<end>[:<flags>]
        start    Starting object number
        end      Ending object number, or -1 for no upper bound
        flags    Optional flags to select object types:
         A    All objects (this is the default)
         d    ZFS directories
         f    ZFS files
         m    SPA space maps
         z    ZAPs
         -    Negate effect of next flag

Examples:

 # Dump all file objects
 zdb -dd tank/fish 0:-1:f

 # Dump all file and directory objects
 zdb -dd tank/fish 0:-1:fd

 # Dump all types except file and directory objects
 zdb -dd tank/fish 0:-1:A-f-d

 # Dump object IDs in a specific range
 zdb -dd tank/fish 1000:2000

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Paul Zuchowski <pzuchowski@datto.com>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Closes #9832

man/man8/zdb.8

@@ -31,12 +31,12 @@
 .Op Fl U Ar cache
 .Op Fl x Ar dumpdir
 .Op Ar poolname[/dataset | objset ID]
-.Op Ar object ...
+.Op Ar object | range ...
 .Nm
 .Op Fl AdiPv
 .Op Fl e Oo Fl V Oc Op Fl p Ar path ...
 .Op Fl U Ar cache
-.Ar poolname[/dataset | objset ID] Op Ar object ...
+.Ar poolname[/dataset | objset ID] Op Ar object | range ...
 .Nm
 .Fl C
 .Op Fl A
@@ -135,8 +135,45 @@ size, and object count.
 .Pp
 If specified multiple times provides greater and greater verbosity.
 .Pp
-If object IDs are specified, display information about those specific objects
-only.
+If object IDs or object ID ranges are specified, display information about
+those specific objects or ranges only.
+.Pp
+An object ID range is specified in terms of a colon-separated tuple of
+the form
+.Ao start Ac Ns : Ns Ao end Ac Ns Op Ns : Ns Ao flags Ac Ns .
+The fields
+.Ar start
+and
+.Ar end
+are integer object identfiers that denote the upper and lower bounds
+of the range. An
+.Ar end
+value of -1 specifies a range with no upper bound. The
+.Ar flags
+field optionally specifies a set of flags, described below, that control
+which object types are dumped. By default, all object types are dumped. A minus
+sign
+.Pq -
+negates the effect of the flag that follows it and has no effect unless
+preceded by the
+.Ar A
+flag. For example, the range 0:-1:A-d will dump all object types except
+for directories.
+.Pp
+.Bl -tag -compact
+.It Sy A
+Dump all objects (this is the default)
+.It Sy d
+Dump ZFS directory objects
+.It Sy f
+Dump ZFS plain file objects
+.It Sy m
+Dump SPA space map objects
+.It Sy z
+Dump ZAP objects
+.It Sy -
+Negate the effect of next flag
+.El
 .It Fl D
 Display deduplication statistics, including the deduplication ratio
 .Pq Sy dedup ,