From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Uday Shankar Date: Wed, 9 Mar 2022 13:03:26 -0700 Subject: [PATCH] multipath-tools: update mpp->force_readonly in ev_add_path When NVMe disks are added to the system, no uevent containing the DISK_RO property is generated. As a result, dm-* nodes backed by readonly NVMe disks will not have their RO state set properly. The result looks like this: $ multipath -l eui.00c92c091fd6564424a9376600011bd1 dm-3 NVME,Pure Storage FlashArray size=1.0T features='0' hwhandler='0' wp=rw |-+- policy='service-time 0' prio=0 status=active | `- 0:2:2:72657 nvme0n2 259:4 active undef running `-+- policy='service-time 0' prio=0 status=enabled `- 1:0:2:72657 nvme1n2 259:1 active undef running $ cat /sys/block/dm-3/ro 0 $ cat /sys/block/nvme*n2/ro 1 1 This is not a problem for SCSI disks, since the kernel will emit change uevents containing the DISK_RO property when the disk is added to the system. See the following thread for my initial attempt to fix this issue at the kernel level: https://lore.kernel.org/linux-block/Yib8GqCA5e3SQYty@infradead.org/T/#t Fix the issue by picking up the path ro state from sysfs in ev_add_path, setting the mpp->force_readonly accordingly, and changing dm_addmap_create to be aware of mpp->force_readonly. Signed-off-by: Uday Shankar Reviewed-by: Benjamin Marzinski Signed-off-by: Benjamin Marzinski --- libmultipath/devmapper.c | 2 +- multipathd/main.c | 6 ++++++ 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c index 3f70e576..e3c3c119 100644 --- a/libmultipath/devmapper.c +++ b/libmultipath/devmapper.c @@ -420,7 +420,7 @@ int dm_addmap_create (struct multipath *mpp, char * params) int ro; uint16_t udev_flags = build_udev_flags(mpp, 0); - for (ro = 0; ro <= 1; ro++) { + for (ro = mpp->force_readonly ? 1 : 0; ro <= 1; ro++) { int err; if (dm_addmap(DM_DEVICE_CREATE, TGT_MPATH, mpp, params, ro, diff --git a/multipathd/main.c b/multipathd/main.c index f4b79882..eeded52b 100644 --- a/multipathd/main.c +++ b/multipathd/main.c @@ -988,6 +988,7 @@ ev_add_path (struct path * pp, struct vectors * vecs, int need_do_map) int retries = 3; int start_waiter = 0; int ret; + int ro; /* * need path UID to go any further @@ -1051,6 +1052,11 @@ rescan: /* persistent reservation check*/ mpath_pr_event_handle(pp); + /* ro check - if new path is ro, force map to be ro as well */ + ro = sysfs_get_ro(pp); + if (ro == 1) + mpp->force_readonly = 1; + if (!need_do_map) return 0;