From c5d781e05599e9e7ad736d42c9c1033992c76ded Mon Sep 17 00:00:00 2001
From: Csaba Henk <csaba@gluster.com>
Date: Sun, 15 May 2011 04:52:33 +0000
Subject: upon daemonizing, wait on mtab update to terminate in parent

This fixes the race in between the mtab update attempts of mount and umount
when we do a lazy umount right after mounting, in order to hide the given fs
instance; yet this way we still avoid the deadlock of the fs and mount which
we can hit if we wait unconditionally for the mtab update to terminate (cf.
bz #511).

Signed-off-by: Csaba Henk <csaba@gluster.com>
Signed-off-by: Anand Avati <avati@gluster.com>

BUG: 2690 (race between mtab updates of mount and umount)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=2690
---
 glusterfsd/src/Makefile.am  | 10 ++--------
 glusterfsd/src/glusterfsd.c | 33 +++++++++++++++++++++++++++------
 2 files changed, 29 insertions(+), 14 deletions(-)

(limited to 'glusterfsd')

diff --git a/glusterfsd/src/Makefile.am b/glusterfsd/src/Makefile.am
index 537eda0bbdd..2056ca89806 100644
--- a/glusterfsd/src/Makefile.am
+++ b/glusterfsd/src/Makefile.am
@@ -1,9 +1,6 @@
 sbin_PROGRAMS = glusterfsd
 
-glusterfsd_SOURCES = glusterfsd.c glusterfsd-mgmt.c
-if GF_DARWIN_HOST_OS
-glusterfsd_SOURCES += $(CONTRIBDIR)/apple/daemon.c
-endif
+glusterfsd_SOURCES = glusterfsd.c glusterfsd-mgmt.c $(CONTRIBDIR)/apple/daemon.c
 glusterfsd_LDADD = $(top_builddir)/libglusterfs/src/libglusterfs.la \
 	$(top_builddir)/rpc/rpc-lib/src/libgfrpc.la \
 	$(top_builddir)/rpc/xdr/src/libgfxdr.la \
@@ -14,10 +11,7 @@ noinst_HEADERS = glusterfsd.h glusterfsd-mem-types.h
 AM_CFLAGS = -fPIC -Wall -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE -D$(GF_HOST_OS)\
 	-I$(top_srcdir)/libglusterfs/src -DDATADIR=\"$(localstatedir)\" \
 	-DCONFDIR=\"$(sysconfdir)/glusterfs\" $(GF_GLUSTERFS_CFLAGS) \
-	-I$(top_srcdir)/rpc/rpc-lib/src -I$(top_srcdir)/rpc/xdr/src
-if GF_DARWIN_HOST_OS
-AM_CFLAGS += -I$(CONTRIBDIR)/apple
-endif
+	-I$(top_srcdir)/rpc/rpc-lib/src -I$(top_srcdir)/rpc/xdr/src -I$(CONTRIBDIR)/apple
 
 CLEANFILES = 
 
diff --git a/glusterfsd/src/glusterfsd.c b/glusterfsd/src/glusterfsd.c
index 9406d74ac63..2d2024409ee 100644
--- a/glusterfsd/src/glusterfsd.c
+++ b/glusterfsd/src/glusterfsd.c
@@ -25,6 +25,7 @@
 #include <sys/types.h>
 #include <sys/resource.h>
 #include <sys/file.h>
+#include <sys/wait.h>
 #include <netdb.h>
 #include <signal.h>
 #include <libgen.h>
@@ -75,11 +76,7 @@
 #include <fnmatch.h>
 #include "rpc-clnt.h"
 
-#ifdef GF_DARWIN_HOST_OS
 #include "daemon.h"
-#else
-#define os_daemon(u, v) daemon (u, v)
-#endif
 
 
 /* using argp for command line parsing */
@@ -315,6 +312,16 @@ create_fuse_mount (glusterfs_ctx_t *ctx)
                 break;
         }
 
+        if (!cmd_args->no_daemon_mode) {
+                 ret = dict_set_static_ptr (master->options, "sync-mtab",
+                                            "enable");
+                if (ret < 0) {
+                        gf_log ("glusterfsd", GF_LOG_ERROR,
+                                "failed to set dict value for key sync-mtab");
+                        goto err;
+                }
+        }
+
         ret = xlator_init (master);
         if (ret) {
                 gf_log ("", GF_LOG_DEBUG, "failed to initialize fuse translator");
@@ -1310,6 +1317,7 @@ daemonize (glusterfs_ctx_t *ctx)
 {
         int            ret = -1;
         cmd_args_t    *cmd_args = NULL;
+        int            cstatus = 0;
 
         cmd_args = &ctx->cmd_args;
 
@@ -1323,11 +1331,24 @@ daemonize (glusterfs_ctx_t *ctx)
         if (cmd_args->debug_mode)
                 goto postfork;
 
-        ret = os_daemon (0, 0);
-        if (ret == -1) {
+        ret = os_daemon_return (0, 0);
+        switch (ret) {
+        case -1:
                 gf_log ("daemonize", GF_LOG_ERROR,
                         "Daemonization failed: %s", strerror(errno));
                 goto out;
+        case 0:
+                break;
+        default:
+                if (ctx->mtab_pid > 0) {
+                        ret = waitpid (ctx->mtab_pid, &cstatus, 0);
+                        if (!(ret == ctx->mtab_pid && cstatus == 0)) {
+                                gf_log ("daemonize", GF_LOG_ERROR,
+                                        "/etc/mtab update failed");
+                                exit (1);
+                        }
+                }
+                _exit (0);
         }
 
 postfork:
-- 
cgit