[PATCH] mkfs: Improve warning when AG size is a multiple of stripe width

[cem@kernel.org]

From: Carlos Maiolino <cmaiolino@redhat.com>

The current output message prints out a suggestion of an AG size to be
used in lieu of the user-defined one.
The problem is this suggestion is printed in filesystem blocks, while
agsize= option receives a size in bytes (or m, g).

This patch tries to make user's life easier by outputing the suggesting
in bytes directly.

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
---
 mkfs/xfs_mkfs.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
index d3a15cf44..827d5b656 100644
--- a/mkfs/xfs_mkfs.c
+++ b/mkfs/xfs_mkfs.c
@@ -3179,9 +3179,11 @@ _("agsize rounded to %lld, sunit = %d\n"),
 		if (cli_opt_set(&dopts, D_AGCOUNT) ||
 		    cli_opt_set(&dopts, D_AGSIZE)) {
 			printf(_(
-"Warning: AG size is a multiple of stripe width.  This can cause performance\n\
-problems by aligning all AGs on the same disk.  To avoid this, run mkfs with\n\
-an AG size that is one stripe unit smaller or larger, for example %llu.\n"),
+"Warning: AG size is a multiple of stripe width. This can cause performance\n\
+problems by aligning all AGs on the same disk. To avoid this, run mkfs with\n\
+an AG size that is one stripe unit smaller or larger,\n\
+for example: agsize=%llu (%llu blks).\n"),
+				(unsigned long long)((cfg->agsize - dsunit) * cfg->blocksize),
 				(unsigned long long)cfg->agsize - dsunit);
 			fflush(stdout);
 			goto validate;
-- 
2.39.2