Return early if there are no xattrs

Saves one malloc(3) and one listxattr(2) per file that has no xattrs.

On my system, this improves `time metastore -d /usr >/dev/null` from:

    real    0m2.347s
    user    0m0.732s
    sys     0m1.603s

to:

    real    0m2.183s
    user    0m0.733s
    sys     0m1.435s

Average of 5 runs, on a warm cache, reducing runtime by roughly 7%.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/metaentry.c b/src/metaentry.c
index fe1c6d1..146fcf9 100644
--- a/src/metaentry.c
+++ b/src/metaentry.c
@@ -251,6 +251,8 @@ mentry_create(const char *path)
 		    path, strerror(errno));
 		return NULL;
 	}
+	if (lsize == 0)
+		return mentry;
 
 	list = xmalloc(lsize);
 	lsize = listxattr(path, list, lsize);