Add zfs_autoimport_disable tunable

There are times when it is desirable for zfs to not automatically
populate the spa namespace at module load time using the pools
in the /etc/zfs/zpool.cache file.  The zfs_autoimport_disable
module option has been added to control this behavior.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #330

diff --git a/module/zfs/spa_config.c b/module/zfs/spa_config.c
index 09149e6..849ae46 100644 (file)
--- a/module/zfs/spa_config.c
+++ b/module/zfs/spa_config.c
@@ -65,6 +65,7 @@ static uint64_t spa_config_generation = 1;
  * userland pools when doing testing.
  */
 char *spa_config_path = ZPOOL_CACHE;
+int zfs_autoimport_disable = 0;
 
 /*
  * Called when the module is first loaded, this routine loads the configuration
@@ -81,6 +82,9 @@ spa_config_load(void)
        struct _buf *file;
        uint64_t fsize;
 
+       if (zfs_autoimport_disable)
+               return;
+
        /*
         * Open the configuration file.
         */
@@ -508,4 +512,8 @@ EXPORT_SYMBOL(spa_config_update);
 
 module_param(spa_config_path, charp, 0444);
 MODULE_PARM_DESC(spa_config_path, "SPA config file (/etc/zfs/zpool.cache)");
+
+module_param(zfs_autoimport_disable, int, 0644);
+MODULE_PARM_DESC(zfs_autoimport_disable, "Disable pool import at module load");
+
 #endif