ext4: fix hot spins in mballoc after err_freebuddy and err_freemeta

In ext4_mb_init_backend() 'i' is of type ext4_group_t. Since unsigned, i
>= 0 is always true, so fix hot spins after err_freebuddy: and -meta:
and prevent decrements when zero.

Signed-off-by: Roel Kluin <12o3l@tiscali.nl>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 11e1fd59acbd37d5c1cee3c3876433b0896ee81b..fbec2ef93797efb9bf6ac16f2a9465fc198dc018 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2272,13 +2272,13 @@ static int ext4_mb_init_backend(struct super_block *sb)
                meta_group_info[j] = kzalloc(len, GFP_KERNEL);
                if (meta_group_info[j] == NULL) {
                        printk(KERN_ERR "EXT4-fs: can't allocate buddy mem\n");
-                       i--;
                        goto err_freebuddy;
                }
                desc = ext4_get_group_desc(sb, i, NULL);
                if (desc == NULL) {
                        printk(KERN_ERR
                                "EXT4-fs: can't read descriptor %lu\n", i);
+                       i++;
                        goto err_freebuddy;
                }
                memset(meta_group_info[j], 0, len);
@@ -2318,13 +2318,11 @@ static int ext4_mb_init_backend(struct super_block *sb)
        return 0;
 
 err_freebuddy:
-       while (i >= 0) {
+       while (i-- > 0)
                kfree(ext4_get_group_info(sb, i));
-               i--;
-       }
        i = num_meta_group_infos;
 err_freemeta:
-       while (--i >= 0)
+       while (i-- > 0)
                kfree(sbi->s_group_info[i]);
        iput(sbi->s_buddy_cache);
 err_freesgi: