[PATCH TAKE 2 6/6] less AGs for single disks configs.

[xaiki@xxxxxxx]

From: Niv Sardi <xaiki@xxxxxxx>

get the underlying structure with get_subvol_stripe_wrapper(),
and pass sunit | swidth as an argument to calc_default_ag_geometry().

if it is set, we are in single disk, get XFS_AG_MAX_BLOCKS for FS >= 4TB,
and calculate ag numbers regarding to that.
get 4 AGs for FS < 4TB.

we calculate according to blocks or count if we have them, add an assert to
ensure we have one of the 2.
---
 xfsprogs/mkfs/xfs_mkfs.c |   28 ++++++++++++++++++++++++----
 1 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/xfsprogs/mkfs/xfs_mkfs.c b/xfsprogs/mkfs/xfs_mkfs.c
index a8af6e2..e15d667 100644
--- a/xfsprogs/mkfs/xfs_mkfs.c
+++ b/xfsprogs/mkfs/xfs_mkfs.c
@@ -401,10 +401,11 @@ void
 calc_default_ag_geometry(
        int             blocklog,
        __uint64_t      dblocks,
+       int             multidisk,
        __uint64_t      *agsize,
        __uint64_t      *agcount)
 {
-       __uint64_t      blocks;
+       __uint64_t      blocks = 0;
        __uint64_t      count = 0;
        int             shift = 0;
 
@@ -436,6 +437,17 @@ calc_default_ag_geometry(
         *
         * This scales us up smoothly between min/max AG sizes.
         */
+
+       if (!multidisk) {
+               if (dblocks >= TERABYTES(4, blocklog)) {
+                        blocks = XFS_AG_MAX_BLOCKS(blocklog);
+                        goto done;
+                }
+                count = 4;
+
+                goto done;
+        }
+
        if (dblocks > GIGABYTES(512, blocklog))
                shift = 5;
        else if (dblocks > GIGABYTES(8, blocklog))
@@ -447,8 +459,12 @@ calc_default_ag_geometry(
        blocks = dblocks >> shift;
 
 done:
+       ASSERT (count || blocks);
        if (!count)
                count = dblocks / blocks + (dblocks % blocks != 0);
+       if (!blocks)
+               blocks = dblocks / count;
+
        *agsize = blocks;
        *agcount = count;
 }
@@ -1779,10 +1795,14 @@ _("size %s specified for log subvolume is too large, 
maximum is %lld blocks\n"),
                agsize /= blocksize;
                agcount = dblocks / agsize + (dblocks % agsize != 0);
 
-       } else if (daflag)      /* User-specified AG size */
+       } else if (daflag)      /* User-specified AG count */
                agsize = dblocks / agcount + (dblocks % agcount != 0);
-       else
-               calc_default_ag_geometry(blocklog, dblocks, &agsize, &agcount);
+       else {
+               get_subvol_stripe_wrapper(dfile, SVTYPE_DATA,
+                                         &xlv_dsunit, &xlv_dswidth, 
&sectoralign),
+                       calc_default_ag_geometry(blocklog, dblocks, xlv_dsunit 
| xlv_dswidth,
+                                                &agsize, &agcount);
+       }
 
        /*
         * If the last AG is too small, reduce the filesystem size
-- 
1.5.3.5