On 07/28/2017 03:28 AM, Guan Junxiong wrote:
> The previous code of path_offline checking was only valid for SCSI
> device. It returned PATH_UP for other devices and throwed path check-
> ing to chekers. This patch supplements checking sysfs path state for
> NVMe/NVMf devices. For example, if NVMe/NVMf path is reconnectting or
> resetting, we return PATH_PENDING in order to skip current path check-
> ing and reschedule path checking in the next tick as soon as possible.
>
> Signed-off-by: Guan Junxiong <[email protected]>
> ---
> libmultipath/discovery.c | 45 +++++++++++++++++++++++++++++++++++----------
> 1 file changed, 35 insertions(+), 10 deletions(-)
>
Thanks for doing this.
> diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c
> index 663c8eaa..b549ce0e 100644
> --- a/libmultipath/discovery.c
> +++ b/libmultipath/discovery.c
> @@ -1383,14 +1383,22 @@ path_offline (struct path * pp)
> struct udev_device * parent;
> char buff[SCSI_STATE_SIZE];
> int err;
> + const char *subsys_type;
>
> - if (pp->bus != SYSFS_BUS_SCSI)
> + if (pp->bus == SYSFS_BUS_SCSI) {
> + subsys_type = "scsi";
> + }
> + else if (pp->bus == SYSFS_BUS_NVME) {
> + subsys_type = "nvme";
> + }
> + else {
> return PATH_UP;
> + }
>
> parent = pp->udev;
> while (parent) {
> const char *subsys = udev_device_get_subsystem(parent);
> - if (subsys && !strncmp(subsys, "scsi", 4))
> + if (subsys && !strncmp(subsys, subsys_type, 4))
> break;
> parent = udev_device_get_parent(parent);
> }
> @@ -1412,15 +1420,32 @@ path_offline (struct path * pp)
>
> condlog(3, "%s: path state = %s", pp->dev, buff);
>
> - if (!strncmp(buff, "offline", 7)) {
> - pp->offline = 1;
> - return PATH_DOWN;
> + if (pp->bus == SYSFS_BUS_SCSI) {
> + if (!strncmp(buff, "offline", 7)) {
> + pp->offline = 1;
> + return PATH_DOWN;
> + }
> + pp->offline = 0;
> + if (!strncmp(buff, "blocked", 7) ||
> + !strncmp(buff, "quiesce", 7))
> + return PATH_PENDING;
> + else if (!strncmp(buff, "running", 7))
> + return PATH_UP;
> +
> + }
> + else if (pp->bus == SYSFS_BUS_NVME) {
> + if (!strncmp(buff, "dead", 4)) {
> + pp->offline = 1;
> + return PATH_DOWN;
> + }
> + pp->offline = 0;
> + if (!strncmp(buff, "new", 3) ||
> + !strncmp(buff, "reconnecting", 12) ||
> + !strncmp(buff, "resetting", 9))
> + return PATH_PENDING;
> + else if (!strncmp(buff, "live", 4))
> + return PATH_UP;
> }
> - pp->offline = 0;
> - if (!strncmp(buff, "blocked", 7) || !strncmp(buff, "quiesce", 7))
> - return PATH_PENDING;
> - else if (!strncmp(buff, "running", 7))
> - return PATH_UP;
>
> return PATH_DOWN;
> }
>
Patch looks good.
Reviewed-by: Hannes Reinecke <[email protected]>
However, I do wonder if we really need a path checker for NVMf once we
have this. After all, the sysfs attribute reflects that KATO status,
which pretty much determines if we can send I/O _at all_.
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
[email protected] +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
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