xfs/170: increase agsize for bigger internal log size

xfs/170: increase agsize for bigger internal log size

xfs/170 always fails on xfs with "-m rmapbt=1,reflink=1", because
XFS need bigger internal log size if rmapbt and reflink are both
enabled.

One line of xfs/170 as below:

  _test_streams 8 16 4 8 3 0 0

Refer to common/filestreams, we can see xfs/170 trys to create a
128M XFS (agcount=8, agsize=16M), then each stream writes
24M (8 * 3M files), and there're 4 streams.

So the case expects each stream takes 2 AGs, 4 streams takes
different 8 AGs just enough. But internal log will break this
balance. For example:

"mkfs.xfs -f -b size=4k -m rmapbt=1,reflink=1 $dev" will take 3075
4k blocks (12M) by default:
  meta-data=/dev/mapper/xxxx-xfscratch isize=512    agcount=8, agsize=4096 blks
  ...
  log      =internal               bsize=4096   blocks=3075, version=2
           =                       sectsz=512   sunit=0 blks, lazy-count=1
  ...

And the internal log is in the 4th AG:
  # xfs_logprint: /dev/mapper/xxxx-xfscratch
  xfs_logprint:
      data device: 0xfd03
      log device: 0xfd03 daddr: 131120 length: 24600
  # xfs_db -c "convert daddr 131120 agno" /dev/mapper/xxxx-xfscratch
  0x4 (4)

Then if one stream write data into AG-1 at first, then turn to AG-4
after fill 16M agsize. But AG-4 has 12M space for log section, so
only 4M free space for data. Then this stream have to turn to the
next AG after fill the 4M space. All these as below:

  # xfs_bmap -vp stream2-dir/*
  stream2-dir/frame-1:
   EXT: FILE-OFFSET      BLOCK-RANGE      AG AG-OFFSET        TOTAL FLAGS
     0: [0..6143]:       32960..39103      1 (192..6335)       6144 000000
  ...
  ...
  stream2-dir/frame-5:
   EXT: FILE-OFFSET      BLOCK-RANGE      AG AG-OFFSET        TOTAL FLAGS
     0: [0..6143]:       57536..63679      1 (24768..30911)    6144 000000
  stream2-dir/frame-6:
   EXT: FILE-OFFSET      BLOCK-RANGE      AG AG-OFFSET        TOTAL FLAGS
     0: [0..6143]:       155776..161919    4 (24704..30847)    6144 000000
  stream2-dir/frame-7:
   EXT: FILE-OFFSET      BLOCK-RANGE      AG AG-OFFSET        TOTAL FLAGS
     0: [0..6143]:       170088..176231    5 (6248..12391)     6144 000000
  stream2-dir/frame-8:
   EXT: FILE-OFFSET      BLOCK-RANGE      AG AG-OFFSET        TOTAL FLAGS
     0: [0..6143]:       176232..182375    5 (12392..18535)    6144 000000

Later _test_streams maybe takes AG-5 again, and cause two streams use
AG-5. To avoid this failure, increase the agsize from 16M to 22M,
others stay the same, each stream still writes 2 AGs. Even internal
log takes some space from someone AG, left space should be enough to
write (24 - 22)=2M data.

Signed-off-by: Zorro Lang <zlang@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>