diff mbox series

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

Message ID 20230629120044.1261968-5-shikemeng@huaweicloud.com
State Superseded
Headers show
Series fixes and cleanups to ext4 resize | expand

Commit Message

Kemeng Shi June 29, 2023, noon UTC 
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@huaweicloud.com>
---
 fs/ext4/resize.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

Comments

Theodore Ts'o Aug. 16, 2023, 3:10 a.m. UTC | #1 
On Thu, Jun 29, 2023 at 08:00:35PM +0800, Kemeng Shi wrote:
> 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@huaweicloud.com>

Reviewed-by: Theodore Ts'o <tytso@mit.edu>
diff mbox series

Patch

diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 0b3d8c808de1..0e83b3f91545 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 */