On Fri, Jun 30, 2023 at 08:14:07PM +0200, mwilck@xxxxxxxx wrote:
> From: Martin Wilck <mwilck@xxxxxxxx>
>
> If the nvme native multipath driver is enabled, blacklist nvme devices
> for dm-multipath by default. This is particularly useful with
> "find_multipaths greedy".
>
> Signed-off-by: Martin Wilck <mwilck@xxxxxxxx>
This looks good. I have two small questions below.
> ---
> libmultipath/blacklist.c | 35 ++++++++++++++++++++++++++++++++---
> tests/blacklist.c | 30 ++++++++++++++++++++++++++++--
> 2 files changed, 60 insertions(+), 5 deletions(-)
>
> diff --git a/libmultipath/blacklist.c b/libmultipath/blacklist.c
> index 8d15d2e..75100b2 100644
> --- a/libmultipath/blacklist.c
> +++ b/libmultipath/blacklist.c
> @@ -2,6 +2,8 @@
> * Copyright (c) 2004, 2005 Christophe Varoqui
> */
> #include <stdio.h>
> +#include <unistd.h>
> +#include <fcntl.h>
> #include <libudev.h>
>
> #include "checkers.h"
> @@ -191,6 +193,27 @@ find_blacklist_device (const struct _vector *blist, const char *vendor,
> return 0;
> }
>
> +/*
> + * Test if nvme native multipath is enabled. If the sysfs file can't
> + * be accessed, multipath is either disabled at compile time, or no
> + * nvme driver is loaded at all. Thus treat errors as "no".
> + */
> +static bool nvme_multipath_enabled(void)
> +{
> + static const char fn[] = "/sys/module/nvme_core/parameters/multipath";
Is there some benefit that I don't understand to using "static const",
instead of just "const"? Obviously, the amount of memory necessary to
keep storing this string outside of the function is very small, but I
don't see why we need to at all.
> + int fd, len;
> + char buf[2];
> +
> + fd = open(fn, O_RDONLY);
> + if (fd == -1)
> + return false;
> +
> + len = read(fd, buf, sizeof(buf));
> + close(fd);
> +
> + return (len >= 1 && buf[0] == 'Y');
> +}
> +
> int
> setup_default_blist (struct config * conf)
> {
> @@ -198,9 +221,15 @@ setup_default_blist (struct config * conf)
> struct hwentry *hwe;
> int i;
>
> - if (store_ble(conf->blist_devnode, "!^(sd[a-z]|dasd[a-z]|nvme[0-9])", ORIGIN_DEFAULT))
> - return 1;
> -
> + if (nvme_multipath_enabled()) {
> + if (store_ble(conf->blist_devnode, "!^(sd[a-z]|dasd[a-z])",
> + ORIGIN_DEFAULT))
> + return 1;
> + } else {
> + if (store_ble(conf->blist_devnode, "!^(sd[a-z]|dasd[a-z]|nvme[0-9])",
> + ORIGIN_DEFAULT))
> + return 1;
> + }
> if (store_ble(conf->elist_property, "(SCSI_IDENT_|ID_WWN)", ORIGIN_DEFAULT))
> return 1;
>
> diff --git a/tests/blacklist.c b/tests/blacklist.c
> index 882aa3a..65002eb 100644
> --- a/tests/blacklist.c
> +++ b/tests/blacklist.c
> @@ -17,6 +17,8 @@
> */
> #include <stdarg.h>
> #include <stddef.h>
> +#include <unistd.h>
> +#include <fcntl.h>
> #include <setjmp.h>
> #include <cmocka.h>
> #include "globals.c"
> @@ -220,12 +222,36 @@ static void test_devnode_missing(void **state)
> MATCH_NOTHING);
> }
Perhaps we should just use #include "../libmultipath/blacklist.c" like
we do for tests where we need get at a file's private
variables/functions ("../libmultipath/alias.c" in alias.c for instance).
-Ben
> +/* copy of the same function in libmultipath/blacklist.c */
> +static bool nvme_multipath_enabled(void)
> +{
> + static const char fn[] = "/sys/module/nvme_core/parameters/multipath";
> + int fd, len;
> + char buf[2];
> +
> + fd = open(fn, O_RDONLY);
> + if (fd == -1)
> + return false;
> +
> + len = read(fd, buf, sizeof(buf));
> + close(fd);
> +
> + return (len >= 1 && buf[0] == 'Y');
> +}
> +
> static void test_devnode_default(void **state)
> {
> assert_int_equal(filter_devnode(blist_devnode_default, NULL, "sdaa"),
> MATCH_NOTHING);
> - assert_int_equal(filter_devnode(blist_devnode_default, NULL, "nvme0n1"),
> - MATCH_NOTHING);
> + if (nvme_multipath_enabled()) {
> + expect_condlog(3, "nvme0n1: device node name blacklisted\n");
> + assert_int_equal(filter_devnode(blist_devnode_default, NULL,
> + "nvme0n1"),
> + MATCH_DEVNODE_BLIST);
> + } else
> + assert_int_equal(filter_devnode(blist_devnode_default, NULL,
> + "nvme0n1"),
> + MATCH_NOTHING);
> assert_int_equal(filter_devnode(blist_devnode_default, NULL, "dasda"),
> MATCH_NOTHING);
> expect_condlog(3, "hda: device node name blacklisted\n");
> --
> 2.41.0
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