Disable zfs /etc/mtab updates

Completely disable the zfs binary from attempting to directly update
/etc/mtab.  The Linux port relies entirely on the mount.zfs helper
to safely update /etc/mtab.  If we left the /etc/mtab updates to
the zfs binary then they could race with concurrent non-zfs mounts.
Routing everything through the system mount command ensures the
/etc/mtab updates are locked properly.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #329

diff --git a/cmd/zfs/zfs_main.c b/cmd/zfs/zfs_main.c
index 54d057b..5354477 100644 (file)
--- a/cmd/zfs/zfs_main.c
+++ b/cmd/zfs/zfs_main.c
@@ -6177,7 +6177,7 @@ main(int argc, char **argv)
        /*
         * Run the appropriate command.
         */
-       libzfs_mnttab_cache(g_zfs, B_TRUE);
+       libzfs_mnttab_cache(g_zfs, B_FALSE);
        if (find_command_idx(cmdname, &i) == 0) {
                current_command = &command_table[i];
                ret = command_table[i].func(argc - 1, argv + 1);
@@ -6191,7 +6191,6 @@ main(int argc, char **argv)
                usage(B_FALSE);
                ret = 1;
        }
-       libzfs_mnttab_cache(g_zfs, B_FALSE);
        libzfs_fini(g_zfs);
 
        (void) fclose(mnttab_file);