Avoid running exportfs on each zfs/zpool command invocation

Delay executing exportfs command until its results are actually
required.

Signed-off-by: Cyril Plisko <cyril.plisko@mountall.com>
Signed-off-by: Gunnar Beutner <gunnar@beutner.name>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>

diff --git a/lib/libshare/nfs.c b/lib/libshare/nfs.c
index 56725d2..53691eb 100644 (file)
--- a/lib/libshare/nfs.c
+++ b/lib/libshare/nfs.c
@@ -22,6 +22,7 @@
 /*
  * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2011 Gunnar Beutner
+ * Copyright (c) 2012 Cyril Plisko. All rights reserved.
  */
 
 #include <stdio.h>
@@ -33,8 +34,9 @@
 #include <libshare.h>
 #include "libshare_impl.h"
 
+static boolean_t nfs_available(void);
+
 static sa_fstype_t *nfs_fstype;
-static boolean_t nfs_available;
 
 /*
  * nfs_exportfs_temp_fd refers to a temporary copy of the output
@@ -407,7 +409,7 @@ nfs_enable_share(sa_share_impl_t impl_share)
        char *shareopts, *linux_opts;
        int rc;
 
-       if (!nfs_available) {
+       if (!nfs_available()) {
                return SA_SYSTEM_ERR;
        }
 
@@ -480,7 +482,7 @@ nfs_disable_share_one(const char *sharepath, const char *host,
 static int
 nfs_disable_share(sa_share_impl_t impl_share)
 {
-       if (!nfs_available) {
+       if (!nfs_available()) {
                /*
                 * The share can't possibly be active, so nothing
                 * needs to be done to disable it.
@@ -520,7 +522,7 @@ is_share_active(sa_share_impl_t impl_share)
        char *tab, *cur;
        FILE *nfs_exportfs_temp_fp;
 
-       if (nfs_exportfs_temp_fd < 0)
+       if (!nfs_available())
                return B_FALSE;
 
        nfs_exportfs_temp_fp = fdopen(dup(nfs_exportfs_temp_fd), "r");
@@ -671,18 +673,27 @@ nfs_check_exportfs(void)
 
        pid = fork();
 
-       if (pid < 0)
+       if (pid < 0) {
+               (void) close(nfs_exportfs_temp_fd);
+               nfs_exportfs_temp_fd = -1;
                return SA_SYSTEM_ERR;
+       }
 
        if (pid > 0) {
                while ((rc = waitpid(pid, &status, 0)) <= 0 && errno == EINTR)
                        ; /* empty loop body */
 
-               if (rc <= 0)
+               if (rc <= 0) {
+                       (void) close(nfs_exportfs_temp_fd);
+                       nfs_exportfs_temp_fd = -1;
                        return SA_SYSTEM_ERR;
+               }
 
-               if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
+               if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+                       (void) close(nfs_exportfs_temp_fd);
+                       nfs_exportfs_temp_fd = -1;
                        return SA_CONFIG_ERR;
+               }
 
                return SA_OK;
        }
@@ -703,13 +714,23 @@ nfs_check_exportfs(void)
        exit(0);
 }
 
+/*
+ * Provides a convenient wrapper for determing nfs availability
+ */
+static boolean_t
+nfs_available(void)
+{
+       if (nfs_exportfs_temp_fd == -1)
+               (void) nfs_check_exportfs();
+
+       return (nfs_exportfs_temp_fd != -1) ? B_TRUE : B_FALSE;
+}
+
 /**
  * Initializes the NFS functionality of libshare.
  */
 void
 libshare_nfs_init(void)
 {
-       nfs_available = (nfs_check_exportfs() == SA_OK);
-
        nfs_fstype = register_fstype("nfs", &nfs_shareops);
 }