From: Eric Sandeen <sandeen@redhat.com>
Date: Mon, 4 Apr 2011 19:11:52 +0000 (-0400)
Subject: mke2fs: don't set stripe/stride to 1 block
X-Git-Tag: v1.42-WIP-0702~34^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d568782ade9b630a6f28f24b1357fc89a6ba8286;p=thirdparty%2Fe2fsprogs.git

mke2fs: don't set stripe/stride to 1 block

Block devices may set minimum or optimal IO hints equal to
blocksize; in this case there is really nothing for ext4
to do with this information (i.e. search for a block-aligned
allocation?) so don't set fs geometry with single-block
values.

Zeev also reported that with a block-sized stripe, the
ext4 allocator spends time spinning in ext4_mb_scan_aligned(),
oddly enough.

Reported-by: Zeev Tarantov <zeev.tarantov@gmail.com>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---

diff --git a/misc/mke2fs.c b/misc/mke2fs.c
index eace0d3a4..9f28901ad 100644
--- a/misc/mke2fs.c
+++ b/misc/mke2fs.c
@@ -1184,8 +1184,11 @@ static int get_device_geometry(const char *file,
 	if ((opt_io == 0) && (psector_size > blocksize))
 		opt_io = psector_size;
 
-	fs_param->s_raid_stride = min_io / blocksize;
-	fs_param->s_raid_stripe_width = opt_io / blocksize;
+	/* setting stripe/stride to blocksize is pointless */
+	if (min_io > blocksize)
+		fs_param->s_raid_stride = min_io / blocksize;
+	if (opt_io > blocksize)
+		fs_param->s_raid_stripe_width = opt_io / blocksize;
 
 	rc = blkid_topology_get_alignment_offset(tp);
 out: