LU-1833 util: don't update mtab if linked to /proc

Some distros may link /etc/mtab to /proc/mounts, or
/proc/self/mounts.  In such case, we don't need to
update mtab. Otherwise we false alart user with
"
mount.lustre: addmntent: Invalid argument:
"

Signed-off-by: Peng Tao <tao.peng@emc.com>
Change-Id: I2e3e213e4ee3bc177865c4ca7435a7eecd274b46
Reviewed-on: http://review.whamcloud.com/3881
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>

diff --git a/lustre/utils/mount_utils.c b/lustre/utils/mount_utils.c
index 49ce369..dc04b78 100644 (file)
--- a/lustre/utils/mount_utils.c
+++ b/lustre/utils/mount_utils.c
@@ -180,6 +180,20 @@ int check_mtab_entry(char *spec1, char *spec2, char *mtpt, char *type)
        return 0;
 }
 
+#define PROC_DIR       "/proc/"
+static int mtab_is_proc(const char *mtab)
+{
+       char path[16];
+
+       if (readlink(mtab, path, sizeof(path)) < 0)
+               return 0;
+
+       if (strncmp(path, PROC_DIR, strlen(PROC_DIR)))
+               return 0;
+
+       return 1;
+}
+
 int update_mtab_entry(char *spec, char *mtpt, char *type, char *opts,
                int flags, int freq, int pass)
 {
@@ -187,6 +201,10 @@ int update_mtab_entry(char *spec, char *mtpt, char *type, char *opts,
        struct mntent mnt;
        int rc = 0;
 
+       /* Don't update mtab if it is linked to any file in /proc direcotry.*/
+       if (mtab_is_proc(MOUNTED))
+               return 0;
+
        mnt.mnt_fsname = spec;
        mnt.mnt_dir = mtpt;
        mnt.mnt_type = type;