vfs: fix panic in __d_lookup() with high dentry hashtable counts

When the number of dentry cache hash table entries gets too high
(2147483648 entries), as happens by default on a 16TB system, use of a
signed integer in the dcache_init() initialization loop prevents the
dentry_hashtable from getting initialized, causing a panic in
__d_lookup().  Fix this in dcache_init() and similar areas.

Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/dcache.c b/fs/dcache.c
index 16a53cc..fe19ac1 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2968,7 +2968,7 @@
 
 static void __init dcache_init_early(void)
 {
-	int loop;
+	unsigned int loop;
 
 	/* If hashes are distributed across NUMA nodes, defer
 	 * hash allocation until vmalloc space is available.
@@ -2986,13 +2986,13 @@
 					&d_hash_mask,
 					0);
 
-	for (loop = 0; loop < (1 << d_hash_shift); loop++)
+	for (loop = 0; loop < (1U << d_hash_shift); loop++)
 		INIT_HLIST_BL_HEAD(dentry_hashtable + loop);
 }
 
 static void __init dcache_init(void)
 {
-	int loop;
+	unsigned int loop;
 
 	/* 
 	 * A constructor could be added for stable state like the lists,
@@ -3016,7 +3016,7 @@
 					&d_hash_mask,
 					0);
 
-	for (loop = 0; loop < (1 << d_hash_shift); loop++)
+	for (loop = 0; loop < (1U << d_hash_shift); loop++)
 		INIT_HLIST_BL_HEAD(dentry_hashtable + loop);
 }