[Cluster-devel] [PATCH] mkfs.gfs2: Don't use i/o limits hints <4K for block size

[Cluster-devel] [PATCH] mkfs.gfs2: Don't use i/o limits hints <4K for block size

[Andrew Price]

Some devices report an optimal_io_size less than 4K. Currently mkfs.gfs2
uses the non-zero value to choose the block size, which is almost
certainly a bad choice when it's less than 4K. Update choose_blocksize()
to avoid using device topology hints for the block size choice when
they're less than the default block size (4K). Test case included.

Resolves: rhbz#1839219
Signed-off-by: Andrew Price <anprice@redhat.com>
---
 gfs2/mkfs/main_mkfs.c | 2 +-
 tests/mkfs.at         | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/gfs2/mkfs/main_mkfs.c b/gfs2/mkfs/main_mkfs.c
index 846b341f..412d4701 100644
--- a/gfs2/mkfs/main_mkfs.c
+++ b/gfs2/mkfs/main_mkfs.c
@@ -505,7 +505,7 @@ static unsigned choose_blocksize(struct mkfs_opts *opts)
 	}
 	if (!opts->got_bsize && got_topol) {
 		if (dev->optimal_io_size <= getpagesize() &&
-		    dev->optimal_io_size >= dev->minimum_io_size)
+		    dev->optimal_io_size >= GFS2_DEFAULT_BSIZE)
 			bsize = dev->optimal_io_size;
 		else if (dev->physical_sector_size <= getpagesize() &&
 		         dev->physical_sector_size >= GFS2_DEFAULT_BSIZE)
diff --git a/tests/mkfs.at b/tests/mkfs.at
index 57785a0d..4c8b2249 100644
--- a/tests/mkfs.at
+++ b/tests/mkfs.at
@@ -112,6 +112,8 @@ AT_CLEANUP
 AT_SETUP([Device i/o limits handling])
 AT_KEYWORDS(mkfs.gfs2 mkfs)
 AT_CHECK([$GFS_MKFS -p lock_nolock -o test_topology=0:0:0:0:0 $GFS_TGT], 0, [ignore], [ignore])
+AT_CHECK([$GFS_MKFS -p lock_nolock -o test_topology=0:512:512:512:512 $GFS_TGT], 0, [ignore], [ignore])
+AT_CHECK([gfs2_edit -p sb field sb_bsize $GFS_TGT | tr -d '\n' ], 0, [4096], [ignore])
 AT_CHECK([$GFS_MKFS -p lock_nolock -o test_topology=7168:512:0:33553920:512 $GFS_TGT], 0, [ignore], [ignore])
 AT_CHECK([$GFS_MKFS -p lock_nolock -o test_topology=7168:512:8192:33553920:512 $GFS_TGT], 0, [ignore], [Warning: device is not properly aligned. This may harm performance.
 ])
-- 
2.26.2