On Tue, Feb 01, 2011 at 10:12:36AM -0600, Jonathan Brassow <jbrassow@redhat.com> wrote:
> > I do not yet have the right to send those patches (I do this in
> > university time, so the copyright is not mine), but I hope to be
> > able to
> > do so - to get them reviewed.
Hi,
I'm attaching the two patches. I tested these on RHEL5, but I don't
think there are major changes in newer versions, either.
If that's the only problem, I can test it on latest linux-2.6.git.
Any feedback is welcome.
Thanks,
Miklos
>From 2a5aaeef1caed0019abdce92fdb6e6a4413677f8 Mon Sep 17 00:00:00 2001
From: Miklos Vajna <vmiklos@ulx.hu>
Date: Sat, 25 Sep 2010 14:56:28 +0200
Subject: [PATCH] dm-mirror: allow setting ios count to 0
Always read from the default_mirror in that case. This can help in case
the default_mirror is way faster than the other data leg.
Signed-off-by: Miklos Vajna <vmiklos@ulx.hu>
---
drivers/md/dm-raid1.c | 15 +++++++++++++--
1 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 23c1d65..318899e 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -849,6 +849,15 @@ static struct mirror *choose_mirror(struct mirror_set *ms)
* the first we tried, so we know when we're done.
*/
ret = start_mirror = ms->read_mirror;
+
+ /*
+ * If MIN_READS is zero, then always use the default one.
+ */
+ if (!atomic_read(&ms->rr_ios_set)) {
+ ret = ms->default_mirror;
+ goto use_mirror;
+ }
+
do {
if (likely(!atomic_read(&ret->error_count) &&
!atomic_dec_and_test(&ms->rr_ios)))
@@ -1848,8 +1857,10 @@ static int mirror_message(struct dm_target *ti, unsigned argc, char **argv)
if (sscanf(argv[3], "%u", &rr_ios_set) != 1 ||
rr_ios_set < 2) {
- DMERR("Round robin read ios have to be > 1");
- return -EINVAL;
+ if (rr_ios_set != 0) {
+ DMERR("Round robin read ios have to be > 1 or 0");
+ return -EINVAL;
+ }
}
md = dm_table_get_md(ti->table);
--
1.5.5.6
>From 02c399b2171dec66d7c014caa1efbc58c0ba8ee1 Mon Sep 17 00:00:00 2001
From: Miklos Vajna <vmiklos@ulx.hu>
Date: Sat, 25 Sep 2010 17:16:11 +0200
Subject: [PATCH] dm-mirror: allow setting the default mirror
This can help in case an other data leg is faster than the default one
and the ios count is set to zero.
Signed-off-by: Miklos Vajna <vmiklos@ulx.hu>
---
drivers/md/dm-raid1.c | 54 +++++++++++++++++++++++++++++++-----------------
1 files changed, 35 insertions(+), 19 deletions(-)
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 318899e..b746b0c 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -1845,31 +1845,47 @@ static void mirror_resume(struct dm_target *ti)
/* Set round robin ios via message. */
static int mirror_message(struct dm_target *ti, unsigned argc, char **argv)
{
- unsigned rr_ios_set;
struct mirror_set *ms = ti->private;
struct mapped_device *md;
- if (argc != 4 ||
- strncmp(argv[0], "io_balance", strlen(argv[0])) ||
- strncmp(argv[1], "round_robin", strlen(argv[1])) ||
- strncmp(argv[2], "ios", strlen(argv[2])))
- return -EINVAL;
-
- if (sscanf(argv[3], "%u", &rr_ios_set) != 1 ||
- rr_ios_set < 2) {
- if (rr_ios_set != 0) {
- DMERR("Round robin read ios have to be > 1 or 0");
- return -EINVAL;
+ if (argc == 4 &&
+ !strncmp(argv[0], "io_balance", strlen(argv[0])) &&
+ !strncmp(argv[1], "round_robin", strlen(argv[1])) &&
+ !strncmp(argv[2], "ios", strlen(argv[2]))) {
+ unsigned rr_ios_set;
+ if (sscanf(argv[3], "%u", &rr_ios_set) != 1 ||
+ rr_ios_set < 2) {
+ if (rr_ios_set != 0) {
+ DMERR("Round robin read ios have to be > 1 or 0");
+ return -EINVAL;
+ }
}
+
+ md = dm_table_get_md(ti->table);
+ DMINFO("Setting round robin read ios for "%s" to %u",
+ dm_device_name(md), rr_ios_set);
+ dm_put(md);
+ atomic_set(&ms->rr_ios_set, rr_ios_set);
+ atomic_set(&ms->rr_ios, rr_ios_set);
+ return 0;
}
- md = dm_table_get_md(ti->table);
- DMINFO("Setting round robin read ios for "%s" to %u",
- dm_device_name(md), rr_ios_set);
- dm_put(md);
- atomic_set(&ms->rr_ios_set, rr_ios_set);
- atomic_set(&ms->rr_ios, rr_ios_set);
- return 0;
+ if (argc == 3 &&
+ !strncmp(argv[0], "io_balance", strlen(argv[0])) &&
+ !strncmp(argv[1], "default", strlen(argv[1]))) {
+ unsigned int m;
+ for (m = 0; m < ms->nr_mirrors; m++)
+ if (!strncmp(argv[2], ms->mirror[m].dev->name, strlen(argv[2]))) {
+ ms->default_mirror = &ms->mirror[m];
+ md = dm_table_get_md(ti->table);
+ DMINFO("Setting default device for "%s" to "%s"",
+ dm_device_name(md), argv[2]);
+ dm_put(md);
+ return 0;
+ }
+ }
+
+ return -EINVAL;
}
/*
--
1.5.5.6
--
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Improving dm-mirror as a final year project
