Hi,

On 27/05/2020 09:29, Andrew Price wrote:
Some devices report an optimal_io_size of 512 instead of 0 when it's not
larger than the minimum_io_size. Currently mkfs.gfs2 uses the non-zero
value to choose the block size, which is almost certainly not what we
want when it's 512. Update the suitability check for optimal_io_size to
avoid using it when it's the same as minimum_io_size.  The effect is
that we fall back to using the default block size, 4096.

Resolves: rhbz#1839219
Signed-off-by: Andrew Price <anpr...@redhat.com>

What about for other sizes? We don't really want to select a block size to be anything other than 4k in most cases, even if the block device offers a lower minimum/optimal I/O size,

Steve.


---
  gfs2/mkfs/main_mkfs.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gfs2/mkfs/main_mkfs.c b/gfs2/mkfs/main_mkfs.c
index 846b341f..8b97f3d2 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 > dev->minimum_io_size)
                        bsize = dev->optimal_io_size;
                else if (dev->physical_sector_size <= getpagesize() &&
                         dev->physical_sector_size >= GFS2_DEFAULT_BSIZE)

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