1 --- linux-4.18/fs/ext4/mballoc.c 2019-11-28 14:55:26.500545920 +0300
2 +++ linux-4.18/fs/ext4/mballoc.c 2019-11-28 14:53:18.600086008 +0300
3 @@ -1885,6 +1885,21 @@ void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
8 +static inline int ext4_mb_uninit_on_disk(struct super_block *sb,
11 + struct ext4_group_desc *desc;
13 + if (!ext4_has_group_desc_csum(sb))
16 + desc = ext4_get_group_desc(sb, group, NULL);
17 + if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))
24 * The routine scans buddy structures (not bitmap!) from given order
25 @@ -2060,7 +2060,15 @@ static int ext4_mb_good_group(struct
27 /* We only do this if the grp has never been initialized */
28 if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
29 - int ret = ext4_mb_init_group(ac->ac_sb, group);
32 + /* cr=0/1 is a very optimistic search to find large
33 + * good chunks almost for free. if buddy data is
34 + * not ready, then this optimization makes no sense */
36 + if (cr < 2 && !ext4_mb_uninit_on_disk(ac->ac_sb, group))
38 + ret = ext4_mb_init_group(ac->ac_sb, group);