[PATCH] mballoc: fix hot spins after err_freebuddy and err_freemeta

[Roel Kluin <12o3l@tiscali.nl>]

ext4_mb_init_backend() has a variable i of type ext4_group_t. which is typedefined
in include/linux/ext4_fs_i.h:34 to unsigned long. Since unsigned, i >= 0 is always
true, so fix hot spins after err_freebuddy and err_freemeta.

Signed-off-by: Roel Kluin <12o3l@tiscali.nl>
---
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index ef97f19..afba9b8 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2618,14 +2618,14 @@ static int ext4_mb_init_backend(struct super_block *sb)
 	return 0;
 
 err_freebuddy:
-	while (i >= 0) {
+	do {
 		kfree(ext4_get_group_info(sb, i));
-		i--;
-	}
-	i = num_meta_group_infos;
+	} while (i-- != 0);
+	i = num_meta_group_infos - 1;
 err_freemeta:
-	while (--i >= 0)
+	do {
 		kfree(sbi->s_group_info[i]);
+	} while (i-- != 0);
 	iput(sbi->s_buddy_cache);
 err_freesgi:
 	kfree(sbi->s_group_info);