[Cluster-devel] [PATCH] qdiskd: Make multipath issues go away
Fabio M. Di Nitto
fdinitto at redhat.com
Fri Feb 17 05:38:42 UTC 2012
The patch looks good and ACK, with one minor nitpick.
that 178 port value in cman_recv/send_data is rather cryptic.
I would prefer to see it defined as others in cman/cnxman-socket.h
for documentation purposes (so we know it's QDISK).
Fabio
On 02/16/2012 12:53 AM, Lon Hohberger wrote:
> Qdiskd hsitorically has required significant tuning to work around
> delays which occur during multipath failover, overloaded I/O, and LUN
> trespasses in both device-mapper-multipath and EMC PowerPath
> environments.
>
> This patch goes a very long way towards eliminating false evictions
> when these conditions occur by making qdiskd whine to the other
> cluster members when it detects hung system calls. When a cluster
> member whines, it indicates the source of the problem (which system
> call is hung), and the act of receiving a whine from a host indicates
> that qdiskd is operational, but that I/O is hung. Hung I/O is different
> from losing storage entirely (where you get I/O errors).
>
> Possible problems:
>
> - Receive queue getting very full, causing messages to become blocked on
> a node where I/O is hung. 1) that would take a very long time, and 2)
> node should get evicted at that point anyway.
>
> Resolves: rhbz#678372
>
> Signed-off-by: Lon Hohberger <lhh at redhat.com>
> ---
> cman/qdisk/Makefile | 2 +-
> cman/qdisk/disk.h | 6 ++++++
> cman/qdisk/iostate.c | 16 +++++++++++++---
> cman/qdisk/iostate.h | 4 +++-
> cman/qdisk/main.c | 45 ++++++++++++++++++++++++++++++++++++++++++---
> 5 files changed, 65 insertions(+), 8 deletions(-)
>
> diff --git a/cman/qdisk/Makefile b/cman/qdisk/Makefile
> index 68e20cd..e3bb5f7 100644
> --- a/cman/qdisk/Makefile
> +++ b/cman/qdisk/Makefile
> @@ -40,7 +40,7 @@ ${TARGET1}: ${SHAREDOBJS} ${OBJS1}
> $(CC) -o $@ $^ $(EXTRA_LDFLAGS) $(LDFLAGS)
>
> ${TARGET2}: ${SHAREDOBJS} ${OBJS2}
> - $(CC) -o $@ $^ $(LDFLAGS)
> + $(CC) -o $@ $^ $(EXTRA_LDFLAGS) $(LDFLAGS)
>
> depends:
> $(MAKE) -C ../lib all
> diff --git a/cman/qdisk/disk.h b/cman/qdisk/disk.h
> index 93d15fe..fd80fa6 100644
> --- a/cman/qdisk/disk.h
> +++ b/cman/qdisk/disk.h
> @@ -273,6 +273,12 @@ typedef struct {
> status_block_t ni_status;
> } node_info_t;
>
> +typedef struct {
> + qd_ctx *ctx;
> + node_info_t *ni;
> + size_t ni_len;
> +} qd_priv_t;
> +
> int qd_write_status(qd_ctx *ctx, int nid, disk_node_state_t state,
> disk_msg_t *msg, memb_mask_t mask, memb_mask_t master);
> int qd_init(qd_ctx *ctx, cman_handle_t ch_admin,
> diff --git a/cman/qdisk/iostate.c b/cman/qdisk/iostate.c
> index 0199da4..06c6831 100644
> --- a/cman/qdisk/iostate.c
> +++ b/cman/qdisk/iostate.c
> @@ -1,9 +1,12 @@
> #include <pthread.h>
> +#include <libcman.h>
> #include <iostate.h>
> #include <unistd.h>
> #include <time.h>
> #include <sys/time.h>
> #include <liblogthread.h>
> +#include <stdint.h>
> +#include "platform.h"
> #include "iostate.h"
>
> static iostate_t main_state = 0;
> @@ -26,7 +29,7 @@ static struct state_table io_state_table[] = {
> { STATE_LSEEK, "seek" },
> { -1, NULL } };
>
> -static const char *
> +const char *
> state_to_string(iostate_t state)
> {
> static const char *ret = "unknown";
> @@ -65,6 +68,8 @@ io_nanny_thread(void *arg)
> iostate_t last_main_state = 0, current_main_state = 0;
> int last_main_incarnation = 0, current_main_incarnation = 0;
> int logged_incarnation = 0;
> + cman_handle_t ch = (cman_handle_t)arg;
> + int32_t whine_state;
>
> /* Start with wherever we're at now */
> pthread_mutex_lock(&state_mutex);
> @@ -96,6 +101,11 @@ io_nanny_thread(void *arg)
> continue;
> }
>
> + /* Whine on CMAN api */
> + whine_state = (int32_t)current_main_state;
> + swab32(whine_state);
> + cman_send_data(ch, &whine_state, sizeof(int32_t), 0, 178, 0);
> +
> /* Don't log things twice */
> if (logged_incarnation == current_main_incarnation)
> continue;
> @@ -114,7 +124,7 @@ io_nanny_thread(void *arg)
>
>
> int
> -io_nanny_start(int timeout)
> +io_nanny_start(cman_handle_t ch, int timeout)
> {
> int ret;
>
> @@ -124,7 +134,7 @@ io_nanny_start(int timeout)
> qdisk_timeout = timeout;
> thread_active = 1;
>
> - ret = pthread_create(&io_nanny_tid, NULL, io_nanny_thread, NULL);
> + ret = pthread_create(&io_nanny_tid, NULL, io_nanny_thread, ch);
> pthread_mutex_unlock(&state_mutex);
>
> return ret;
> diff --git a/cman/qdisk/iostate.h b/cman/qdisk/iostate.h
> index 7dd7bf6..a65b1d4 100644
> --- a/cman/qdisk/iostate.h
> +++ b/cman/qdisk/iostate.h
> @@ -11,7 +11,9 @@ typedef enum {
>
> void io_state(iostate_t state);
>
> -int io_nanny_start(int timeout);
> +int io_nanny_start(cman_handle_t ch, int timeout);
> int io_nanny_stop(void);
>
> +const char * state_to_string(iostate_t state);
> +
> #endif
> diff --git a/cman/qdisk/main.c b/cman/qdisk/main.c
> index a90e82c..d613d84 100644
> --- a/cman/qdisk/main.c
> +++ b/cman/qdisk/main.c
> @@ -915,7 +915,8 @@ cman_wait(cman_handle_t ch, struct timeval *_tv)
> static void
> process_cman_event(cman_handle_t handle, void *private, int reason, int arg)
> {
> - qd_ctx *ctx = (qd_ctx *)private;
> + qd_priv_t *qp = (qd_priv_t *)private;
> + qd_ctx *ctx = qp->ctx;
>
> switch(reason) {
> case CMAN_REASON_PORTOPENED:
> @@ -1926,6 +1927,33 @@ check_stop_cman(qd_ctx *ctx)
> do { static int _logged=0; if (!_logged) { _logged=1; logt_print(level, fmt, ##args); } } while(0)
>
>
> +static void
> +qdisk_whine(cman_handle_t h, void *privdata, char *buf, int len,
> + uint8_t port, int nodeid)
> +{
> + int32_t dstate;
> + qd_priv_t *qp = (qd_priv_t *)privdata;
> + node_info_t *ni = qp->ni;
> +
> + if (len != sizeof(dstate)) {
> + return;
> + }
> +
> + dstate = *((int32_t*)buf);
> +
> + if (nodeid == (qp->ctx->qc_my_id))
> + return;
> +
> + swab32(dstate);
> +
> + if (dstate) {
> + logt_print(LOG_NOTICE, "qdiskd on node %d reports hung %s()\n", nodeid,
> + state_to_string(dstate));
> + ni[nodeid-1].ni_misses = 0;
> + }
> +}
> +
> +
> int
> main(int argc, char **argv)
> {
> @@ -1939,6 +1967,7 @@ main(int argc, char **argv)
> char device[128];
> pid_t pid;
> quorum_header_t qh;
> + qd_priv_t qp;
>
> if (check_process_running(argv[0], &pid) && pid !=getpid()) {
> printf("QDisk services already running\n");
> @@ -2001,13 +2030,23 @@ main(int argc, char **argv)
>
> /* For cman notifications we need two sockets - one for events,
> one for config change callbacks */
> - ch_user = cman_init(&ctx);
> + qp.ctx = &ctx;
> + qp.ni = &ni[0];
> + qp.ni_len = MAX_NODES_DISK;
> +
> + ch_user = cman_init(&qp);
> if (cman_start_notification(ch_user, process_cman_event) != 0) {
> logt_print(LOG_CRIT, "Could not register with CMAN: %s\n",
> strerror(errno));
> goto out;
> }
>
> + if (cman_start_recv_data(ch_user, qdisk_whine, 178) != 0) {
> + logt_print(LOG_CRIT, "Could not register with CMAN: %s\n",
> + strerror(errno));
> + goto out;
> + }
> +
> memset(&me, 0, sizeof(me));
> if (cman_get_node(ch_admin, CMAN_NODEID_US, &me) < 0) {
> logt_print(LOG_CRIT, "Could not determine local node ID: %s\n",
> @@ -2108,7 +2147,7 @@ main(int argc, char **argv)
> }
> }
>
> - io_nanny_start(ctx.qc_tko * ctx.qc_interval);
> + io_nanny_start(ch_user, ctx.qc_tko * ctx.qc_interval);
>
> if (quorum_loop(&ctx, ni, MAX_NODES_DISK) == 0) {
> /* Only clean up if we're exiting w/o error) */
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