Gitweb: http://git.fedorahosted.org/git/cluster.git?p=cluster.git;a=commitdiff;h=e29... Commit: e2937eb33f224f86904fead08499a6178868ca6a Parent: 6707ff0f2a248dd0a05e13d9f563806cd93c6cb4 Author: Lon Hohberger lhh@redhat.com AuthorDate: Fri May 6 10:14:04 2011 -0400 Committer: Lon Hohberger lhh@redhat.com CommitterDate: Thu Jun 23 13:42:41 2011 -0400

qdiskd: Make multipath issues go away

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.

Signed-off-by: Lon Hohberger lhh@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 9262af2..c1598fa 100644 --- a/cman/qdisk/main.c +++ b/cman/qdisk/main.c @@ -904,7 +904,8 @@ 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: @@ -1915,6 +1916,33 @@ 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) { @@ -1928,6 +1956,7 @@ 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"); @@ -1990,13 +2019,23 @@ 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", @@ -2084,7 +2123,7 @@ main(int argc, char **argv) /* This registers the quorum device */ register_device(&ctx);

- 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) */