Hi Ritesh,
> -----Original Message-----
> From: Ritesh Harjani <ritesh.list@xxxxxxxxx>
> Sent: Wednesday, March 6, 2024 9:32 AM
> To: Srivathsa Dara <srivathsa.d.dara@xxxxxxxxxx>; linux-ext4@xxxxxxxxxxxxxxx
> Cc: tytso@xxxxxxx; adilger.kernel@xxxxxxxxx; Rajesh Sivaramasubramaniom <rajesh.sivaramasubramaniom@xxxxxxxxxx>; Junxiao Bi <junxiao.bi@xxxxxxxxxx>
> Subject: Re: [PATCH] ext4: Enable meta_bg only when new desc blocks are needed
>
> Srivathsa Dara <srivathsa.d.dara@xxxxxxxxxx> writes:
>
> > This patch addresses an issue observed when resize_inode is disabled
>
> Other than "meta_bg unwatedly getting enabled when not required", is there any other issue you observed?
Yes, we have seen an issue where a data block is being corrupted by group
descriptor block because of this. The following patch fixes that issue.
ext4: fix corruption during on-line resize
commit: 3a944549dd26ccaf1f898a4be952e75a42bf37dd
>
> > and an online extension of a filesysyem is performed. When a
> > filesystem is expanded to a size that does not require a addition of a
> > new descriptor block, the meta_bg feature is being enabled even though
> > no part of the filesystem uses this layout.
> >
> > This patch ensures that the meta_bg feature is only enabled if any of
> > the added block groups utilize meta_bg layout.
>
> Make sense to me.
>
> >
> > Signed-off-by: Srivathsa Dara <srivathsa.d.dara@xxxxxxxxxx>
> > ---
> > fs/ext4/resize.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c index
> > 928700d57eb6..99b52f26e818 100644
> > --- a/fs/ext4/resize.c
> > +++ b/fs/ext4/resize.c
> > @@ -1996,7 +1996,7 @@ int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
> > }
> > }
> >
> > - if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
> > + if ((!resize_inode && !meta_bg && n_desc_blocks > o_desc_blocks) ||
> > +n_blocks_count == o_blocks_count) {
>
> Beyond 80 chars line. You might want to fix that.
Sorry, I missed that, will send a V2.
>
> -ritesh
>
> > err = ext4_convert_meta_bg(sb, resize_inode);
> > if (err)
> > goto out;
> > --
> > 2.39.3
Thanks,
Srivathsa Dara
