[PATCH v2 04/13] ext4: remove gdb backup copy for meta bg in setup_new_flex_group_blocks

From: Kemeng Shi
Date: Sat Aug 26 2023 - 05:39:47 EST


Wrong check of gdb backup in meta bg as following:
first_group is the first group of meta_bg which contains target group, so
target group is always >= first_group. We check if target group has gdb
backup by comparing first_group with [group + 1] and [group +
EXT4_DESC_PER_BLOCK(sb) - 1]. As group >= first_group, then [group + N] is
> first_group. So no copy of gdb backup in meta bg is done in
setup_new_flex_group_blocks.

No need to do gdb backup copy in meta bg from setup_new_flex_group_blocks
as we always copy updated gdb block to backups at end of
ext4_flex_group_add as following:

ext4_flex_group_add
/* no gdb backup copy for meta bg any more */
setup_new_flex_group_blocks

/* update current group number */
ext4_update_super
sbi->s_groups_count += flex_gd->count;

/*
* if group in meta bg contains backup is added, the primary gdb block
* of the meta bg will be copy to backup in new added group here.
*/
for (; gdb_num <= gdb_num_end; gdb_num++)
update_backups(...)

In summary, we can remove wrong gdb backup copy code in
setup_new_flex_group_blocks.

Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
Reviewed-by: Theodore Ts'o <tytso@xxxxxxx>
---
fs/ext4/resize.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 9cb9ed968599..667381180b26 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -560,13 +560,8 @@ static int setup_new_flex_group_blocks(struct super_block *sb,
if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
goto handle_itb;

- if (meta_bg == 1) {
- ext4_group_t first_group;
- first_group = ext4_meta_bg_first_group(sb, group);
- if (first_group != group + 1 &&
- first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
- goto handle_itb;
- }
+ if (meta_bg == 1)
+ goto handle_itb;

block = start + ext4_bg_has_super(sb, group);
/* Copy all of the GDT blocks into the backup in this group */
--
2.30.0