Patch "ext4: remove redundant mb_regenerate_buddy()" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    ext4: remove redundant mb_regenerate_buddy()

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ext4-remove-redundant-mb_regenerate_buddy.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit bf1eaae54c4ed67e01a5d40d0c8bfee45446248b
Author: Chunguang Xu <brookxu@xxxxxxxxxxx>
Date:   Sat Nov 7 23:58:12 2020 +0800

    ext4: remove redundant mb_regenerate_buddy()
    
    [ Upstream commit 6bd97bf273bdb4944904e57480f6545bca48ad77 ]
    
    After this patch (163a203), if an abnormal bitmap is detected, we
    will mark the group as corrupt, and we will not use this group in
    the future. Therefore, it should be meaningless to regenerate the
    buddy bitmap of this group, It might be better to delete it.
    
    Signed-off-by: Chunguang Xu <brookxu@xxxxxxxxxxx>
    Reviewed-by: Andreas Dilger <adilger@xxxxxxxxx>
    Link: https://lore.kernel.org/r/1604764698-4269-2-git-send-email-brookxu@xxxxxxxxxxx
    Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
    Stable-dep-of: 5354b2af3406 ("ext4: allow ext4_get_group_info() to fail")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index a7c42e4bfc5ec..708a5fa3c69f6 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -822,24 +822,6 @@ void ext4_mb_generate_buddy(struct super_block *sb,
 	spin_unlock(&sbi->s_bal_lock);
 }
 
-static void mb_regenerate_buddy(struct ext4_buddy *e4b)
-{
-	int count;
-	int order = 1;
-	void *buddy;
-
-	while ((buddy = mb_find_buddy(e4b, order++, &count))) {
-		ext4_set_bits(buddy, 0, count);
-	}
-	e4b->bd_info->bb_fragments = 0;
-	memset(e4b->bd_info->bb_counters, 0,
-		sizeof(*e4b->bd_info->bb_counters) *
-		(e4b->bd_sb->s_blocksize_bits + 2));
-
-	ext4_mb_generate_buddy(e4b->bd_sb, e4b->bd_buddy,
-		e4b->bd_bitmap, e4b->bd_group);
-}
-
 /* The buddy information is attached the buddy cache inode
  * for convenience. The information regarding each group
  * is loaded via ext4_mb_load_buddy. The information involve
@@ -1512,7 +1494,6 @@ static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
 				sb, e4b->bd_group,
 				EXT4_GROUP_INFO_BBITMAP_CORRUPT);
 		}
-		mb_regenerate_buddy(e4b);
 		goto done;
 	}