Now that I am using white-space mode in Emacs I can see all of this, and I don't like it :-) Signed-off-by: NeilBrown <neilb@suse.de>
476 lines
10 KiB
C
476 lines
10 KiB
C
/*
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* Copyright (C) 2008 Intel Corporation
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*
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* mdmon socket / message handling
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifndef _GNU_SOURCE
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#define _GNU_SOURCE
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#endif
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#include <unistd.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/un.h>
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#include "mdadm.h"
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#include "mdmon.h"
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static const __u32 start_magic = 0x5a5aa5a5;
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static const __u32 end_magic = 0xa5a55a5a;
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static int send_buf(int fd, const void* buf, int len, int tmo)
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{
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fd_set set;
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int rv;
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struct timeval timeout = {tmo, 0};
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struct timeval *ptmo = tmo ? &timeout : NULL;
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while (len) {
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FD_ZERO(&set);
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FD_SET(fd, &set);
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rv = select(fd+1, NULL, &set, NULL, ptmo);
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if (rv <= 0)
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return -1;
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rv = write(fd, buf, len);
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if (rv <= 0)
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return -1;
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len -= rv;
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buf += rv;
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}
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return 0;
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}
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static int recv_buf(int fd, void* buf, int len, int tmo)
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{
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fd_set set;
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int rv;
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struct timeval timeout = {tmo, 0};
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struct timeval *ptmo = tmo ? &timeout : NULL;
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while (len) {
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FD_ZERO(&set);
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FD_SET(fd, &set);
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rv = select(fd+1, &set, NULL, NULL, ptmo);
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if (rv <= 0)
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return -1;
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rv = read(fd, buf, len);
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if (rv <= 0)
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return -1;
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len -= rv;
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buf += rv;
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}
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return 0;
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}
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int send_message(int fd, struct metadata_update *msg, int tmo)
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{
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__s32 len = msg->len;
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int rv;
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rv = send_buf(fd, &start_magic, 4, tmo);
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rv = rv ?: send_buf(fd, &len, 4, tmo);
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if (len > 0)
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rv = rv ?: send_buf(fd, msg->buf, msg->len, tmo);
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rv = send_buf(fd, &end_magic, 4, tmo);
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return rv;
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}
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int receive_message(int fd, struct metadata_update *msg, int tmo)
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{
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__u32 magic;
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__s32 len;
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int rv;
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rv = recv_buf(fd, &magic, 4, tmo);
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if (rv < 0 || magic != start_magic)
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return -1;
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rv = recv_buf(fd, &len, 4, tmo);
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if (rv < 0 || len > MSG_MAX_LEN)
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return -1;
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if (len > 0) {
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msg->buf = xmalloc(len);
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rv = recv_buf(fd, msg->buf, len, tmo);
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if (rv < 0) {
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free(msg->buf);
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return -1;
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}
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} else
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msg->buf = NULL;
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rv = recv_buf(fd, &magic, 4, tmo);
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if (rv < 0 || magic != end_magic) {
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free(msg->buf);
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return -1;
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}
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msg->len = len;
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return 0;
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}
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int ack(int fd, int tmo)
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{
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struct metadata_update msg = { .len = 0 };
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return send_message(fd, &msg, tmo);
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}
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int wait_reply(int fd, int tmo)
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{
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struct metadata_update msg;
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int err = receive_message(fd, &msg, tmo);
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/* mdmon sent extra data, but caller only cares that we got a
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* successful reply
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*/
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if (err == 0 && msg.len > 0)
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free(msg.buf);
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return err;
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}
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int connect_monitor(char *devname)
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{
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char path[100];
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int sfd;
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long fl;
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struct sockaddr_un addr;
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int pos;
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char *c;
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pos = sprintf(path, "%s/", MDMON_DIR);
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if (is_subarray(devname)) {
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devname++;
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c = strchr(devname, '/');
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if (!c)
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return -1;
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snprintf(&path[pos], c - devname + 1, "%s", devname);
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pos += c - devname;
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} else
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pos += sprintf(&path[pos], "%s", devname);
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sprintf(&path[pos], ".sock");
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sfd = socket(PF_LOCAL, SOCK_STREAM, 0);
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if (sfd < 0)
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return -1;
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addr.sun_family = PF_LOCAL;
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strcpy(addr.sun_path, path);
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if (connect(sfd, &addr, sizeof(addr)) < 0) {
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close(sfd);
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return -1;
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}
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fl = fcntl(sfd, F_GETFL, 0);
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fl |= O_NONBLOCK;
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fcntl(sfd, F_SETFL, fl);
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return sfd;
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}
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int fping_monitor(int sfd)
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{
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int err = 0;
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if (sfd < 0)
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return sfd;
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/* try to ping existing socket */
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if (ack(sfd, 20) != 0)
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err = -1;
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/* check the reply */
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if (!err && wait_reply(sfd, 20) != 0)
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err = -1;
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return err;
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}
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/* give the monitor a chance to update the metadata */
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int ping_monitor(char *devname)
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{
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int sfd = connect_monitor(devname);
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int err;
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if (sfd >= 0) {
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err = fping_monitor(sfd);
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close(sfd);
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} else
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err = -1;
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return err;
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}
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static char *ping_monitor_version(char *devname)
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{
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int sfd = connect_monitor(devname);
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struct metadata_update msg;
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int err = 0;
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if (sfd < 0)
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return NULL;
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if (ack(sfd, 20) != 0)
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err = -1;
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if (!err && receive_message(sfd, &msg, 20) != 0)
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err = -1;
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close(sfd);
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if (err || !msg.len || !msg.buf)
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return NULL;
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return msg.buf;
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}
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int unblock_subarray(struct mdinfo *sra, const int unfreeze)
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{
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char buf[64];
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int rc = 0;
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if (sra) {
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sprintf(buf, "external:%s\n", sra->text_version);
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buf[9] = '/';
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} else
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buf[9] = '-';
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if (buf[9] == '-' ||
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sysfs_set_str(sra, NULL, "metadata_version", buf) ||
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(unfreeze &&
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sysfs_attribute_available(sra, NULL, "sync_action") &&
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sysfs_set_str(sra, NULL, "sync_action", "idle")))
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rc = -1;
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return rc;
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}
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int block_subarray(struct mdinfo *sra)
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{
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char buf[64];
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int rc = 0;
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sprintf(buf, "external:%s\n", sra->text_version);
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buf[9] = '-';
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if (sysfs_set_str(sra, NULL, "metadata_version", buf))
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rc = -1;
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return rc;
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}
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/* check mdmon version if it supports
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* array blocking mechanism
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*/
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int check_mdmon_version(char *container)
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{
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char *version = NULL;
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if (!mdmon_running(container)) {
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/* if mdmon is not active we assume that any instance that is
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* later started will match the current mdadm version, if this
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* assumption is violated we may inadvertantly rebuild an array
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* that was meant for reshape, or start rebuild on a spare that
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* was to be moved to another container
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*/
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/* pass */;
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} else {
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int ver;
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version = ping_monitor_version(container);
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ver = version ? mdadm_version(version) : -1;
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free(version);
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if (ver < 3002000) {
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pr_err("mdmon instance for %s cannot be disabled\n",
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container);
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return -1;
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}
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}
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return 0;
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}
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/**
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* block_monitor - prevent mdmon spare assignment
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* @container - container to block
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* @freeze - flag to additionally freeze sync_action
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*
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* This is used by the reshape code to freeze the container, and the
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* auto-rebuild implementation to atomically move spares.
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* In both cases we need to stop mdmon from assigning spares to replace
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* failed devices as we might have other plans for the spare.
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* For the reshape case we also need to 'freeze' sync_action so that
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* no recovery happens until we have fully prepared for the reshape.
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*
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* We tell mdmon that the array is frozen by marking the 'metadata' name
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* with a leading '-'. The previously told mdmon "Don't make this array
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* read/write, leave it readonly". Now it means a more general "Don't
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* reconfigure this array at all".
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* As older versions of mdmon (which might run from initrd) don't understand
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* this, we first check that the running mdmon is new enough.
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*/
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int block_monitor(char *container, const int freeze)
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{
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struct mdstat_ent *ent, *e, *e2;
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struct mdinfo *sra = NULL;
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char buf[64];
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int rv = 0;
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if (check_mdmon_version(container))
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return -1;
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ent = mdstat_read(0, 0);
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if (!ent) {
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pr_err("failed to read /proc/mdstat while disabling mdmon\n");
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return -1;
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}
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/* freeze container contents */
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for (e = ent; e; e = e->next) {
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if (!is_container_member(e, container))
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continue;
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sysfs_free(sra);
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sra = sysfs_read(-1, e->devnm, GET_VERSION);
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if (!sra) {
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pr_err("failed to read sysfs for subarray%s\n",
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to_subarray(e, container));
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break;
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}
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/* can't reshape an array that we can't monitor */
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if (sra->text_version[0] == '-')
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break;
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if (freeze && sysfs_freeze_array(sra) < 1)
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break;
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/* flag this array to not be modified by mdmon (close race with
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* takeover in reshape case and spare reassignment in the
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* auto-rebuild case)
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*/
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if (block_subarray(sra))
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break;
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ping_monitor(container);
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/* check that we did not race with recovery */
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if ((freeze &&
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!sysfs_attribute_available(sra, NULL, "sync_action")) ||
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(freeze &&
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sysfs_attribute_available(sra, NULL, "sync_action") &&
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sysfs_get_str(sra, NULL, "sync_action", buf, 20) > 0 &&
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strcmp(buf, "frozen\n") == 0))
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/* pass */;
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else {
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unblock_subarray(sra, 0);
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break;
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}
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/* Double check against races - there should be no spares
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* or part-spares
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*/
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sysfs_free(sra);
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sra = sysfs_read(-1, e->devnm, GET_DEVS | GET_STATE);
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if (sra && sra->array.spare_disks > 0) {
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unblock_subarray(sra, freeze);
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break;
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}
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}
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if (e) {
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pr_err("failed to freeze subarray%s\n",
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to_subarray(e, container));
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/* thaw the partially frozen container */
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for (e2 = ent; e2 && e2 != e; e2 = e2->next) {
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if (!is_container_member(e2, container))
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continue;
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sysfs_free(sra);
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sra = sysfs_read(-1, e2->devnm, GET_VERSION);
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if (unblock_subarray(sra, freeze))
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pr_err("Failed to unfreeze %s\n", e2->dev);
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}
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ping_monitor(container); /* cleared frozen */
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rv = -1;
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}
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sysfs_free(sra);
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free_mdstat(ent);
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return rv;
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}
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void unblock_monitor(char *container, const int unfreeze)
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{
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struct mdstat_ent *ent, *e;
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struct mdinfo *sra = NULL;
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int to_ping = 0;
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ent = mdstat_read(0, 0);
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if (!ent) {
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pr_err("failed to read /proc/mdstat while unblocking container\n");
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return;
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}
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/* unfreeze container contents */
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for (e = ent; e; e = e->next) {
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if (!is_container_member(e, container))
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continue;
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sysfs_free(sra);
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sra = sysfs_read(-1, e->devnm, GET_VERSION|GET_LEVEL);
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if (!sra)
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continue;
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if (sra->array.level > 0)
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to_ping++;
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if (unblock_subarray(sra, unfreeze))
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pr_err("Failed to unfreeze %s\n", e->dev);
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}
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if (to_ping)
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ping_monitor(container);
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sysfs_free(sra);
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free_mdstat(ent);
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}
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/* give the manager a chance to view the updated container state. This
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* would naturally happen due to the manager noticing a change in
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* /proc/mdstat; however, pinging encourages this detection to happen
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* while an exclusive open() on the container is active
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*/
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int ping_manager(char *devname)
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{
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int sfd = connect_monitor(devname);
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struct metadata_update msg = { .len = -1 };
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int err = 0;
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if (sfd < 0)
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return sfd;
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err = send_message(sfd, &msg, 20);
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/* check the reply */
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if (!err && wait_reply(sfd, 20) != 0)
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err = -1;
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close(sfd);
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return err;
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}
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/* using takeover operation for grow purposes, mdadm has to be sure
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* that mdmon processes all updates, and if necessary it will be closed
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* at takeover to raid0 operation
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*/
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void flush_mdmon(char *container)
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{
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ping_manager(container);
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ping_monitor(container);
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}
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