Date: Sat, 6 Jun 2020 00:40:02 +0000 (UTC) From: Rick Macklem <rmacklem@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r361854 - head/usr.sbin/mountd Message-ID: <202006060040.0560e263021511@repo.freebsd.org>
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Author: rmacklem Date: Sat Jun 6 00:40:02 2020 New Revision: 361854 URL: https://svnweb.freebsd.org/changeset/base/361854 Log: Fix mountd so that it will not lose SIGHUPs that indicate "reload exports". Without this patch, if a SIGHUP is handled while the process is executing get_exportlist(), that SIGHUP is essentially ignored because the got_sighup variable is reset to 0 after get_exportlist(). This results in the exports file(s) not being reloaded until another SIGHUP signal is sent to mountd. This patch fixes this by resetting got_sighup to zero before the get_exportlist() call while SIGHUP is blocked. It also defines a delay time of 250msec before doing another exports reload if there are RPC request(s) to process. This prevents repeated exports reloads from delaying handling of RPC requests significantly. PR: 246597 Reported by: patrykkotlowski@gmail.com Tested by: patrykkotlowski@gmail.com Reviewed by: markj MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D25127 Modified: head/usr.sbin/mountd/mountd.c Modified: head/usr.sbin/mountd/mountd.c ============================================================================== --- head/usr.sbin/mountd/mountd.c Sat Jun 6 00:35:41 2020 (r361853) +++ head/usr.sbin/mountd/mountd.c Sat Jun 6 00:40:02 2020 (r361854) @@ -184,6 +184,12 @@ struct fhreturn { #define GETPORT_MAXTRY 20 /* Max tries to get a port # */ +/* + * How long to delay a reload of exports when there are RPC request(s) + * to process, in usec. Must be less than 1second. + */ +#define RELOADDELAY 250000 + /* Global defs */ static char *add_expdir(struct dirlist **, char *, int); static void add_dlist(struct dirlist **, struct dirlist *, @@ -410,6 +416,10 @@ main(int argc, char **argv) int maxrec = RPC_MAXDATASIZE; int attempt_cnt, port_len, port_pos, ret; char **port_list; + uint64_t curtime, nexttime; + struct timeval tv; + struct timespec tp; + sigset_t sighup_mask; /* Check that another mountd isn't already running. */ pfh = pidfile_open(_PATH_MOUNTDPID, 0600, &otherpid); @@ -665,19 +675,49 @@ main(int argc, char **argv) } /* Expand svc_run() here so that we can call get_exportlist(). */ + curtime = nexttime = 0; + sigemptyset(&sighup_mask); + sigaddset(&sighup_mask, SIGHUP); for (;;) { - if (got_sighup) { - get_exportlist(1); + clock_gettime(CLOCK_MONOTONIC, &tp); + curtime = tp.tv_sec; + curtime = curtime * 1000000 + tp.tv_nsec / 1000; + sigprocmask(SIG_BLOCK, &sighup_mask, NULL); + if (got_sighup && curtime >= nexttime) { got_sighup = 0; - } + sigprocmask(SIG_UNBLOCK, &sighup_mask, NULL); + get_exportlist(1); + clock_gettime(CLOCK_MONOTONIC, &tp); + nexttime = tp.tv_sec; + nexttime = nexttime * 1000000 + tp.tv_nsec / 1000 + + RELOADDELAY; + } else + sigprocmask(SIG_UNBLOCK, &sighup_mask, NULL); + + /* + * If a reload is pending, poll for received request(s), + * otherwise set a RELOADDELAY timeout, since a SIGHUP + * could be processed between the got_sighup test and + * the select() system call. + */ + tv.tv_sec = 0; + if (got_sighup) + tv.tv_usec = 0; + else + tv.tv_usec = RELOADDELAY; readfds = svc_fdset; - switch (select(svc_maxfd + 1, &readfds, NULL, NULL, NULL)) { + switch (select(svc_maxfd + 1, &readfds, NULL, NULL, &tv)) { case -1: - if (errno == EINTR) - continue; + if (errno == EINTR) { + /* Allow a reload now. */ + nexttime = 0; + continue; + } syslog(LOG_ERR, "mountd died: select: %m"); exit(1); case 0: + /* Allow a reload now. */ + nexttime = 0; continue; default: svc_getreqset(&readfds);
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