On 27/05/2020 09:53, Steven Whitehouse wrote:
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,
I think it would be unusual for a device to have an optimal_io_size >
512 and < 4K, and I expect it's only 512 for the tested device because
of some design or configuration error, so we're still covering most
cases anyway. I figured that any other optimal_io_size is likely to be
one that's there for a good reason and so we should probably use it (if
suitable).
That's just my reasoning for this patch though. I can see the value in
ignoring optimal_io_size < 4K, but it poses the question of whether
there's any value in allowing mkfs.gfs2 to create < 4K block size
filesystems at all.
Andy
---
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)
