Re: [PATCH] f2fs: fix error path of __f2fs_build_free_nids

[Zhiguo Niu]

Dear Chao,

On Mon, Oct 16, 2023 at 3:37 PM Chao Yu <chao@xxxxxxxxxx> wrote:
>
> On 2023/10/13 18:58, Zhiguo Niu wrote:
> > SBI_NEED_FSCK should be set for fsck has a chance to
> > repair in case of scan_nat_page fail in run time.
> >
> > Signed-off-by: Zhiguo Niu <zhiguo.niu@xxxxxxxxxx>
>
> Hi Zhiguo,
>
> Can you please check below update?
>
>  From 9a3459d2d62a12f8708d72aa7808a1def9f9d92f Mon Sep 17 00:00:00 2001
> From: Zhiguo Niu <zhiguo.niu@xxxxxxxxxx>
> Date: Fri, 13 Oct 2023 18:58:23 +0800
> Subject: [PATCH] f2fs: fix error path of __f2fs_build_free_nids
>
> If NAT is corrupted, let scan_nat_page() return EFSCORRUPTED, so that,
> caller can set SBI_NEED_FSCK flag into checkpoint for later repair by
> fsck.
>
> Also, this patch introduces a new fscorrupted error flag, and in above
> scenario, it will persist the error flag into superblock synchronously
> to avoid it has no luck to trigger a checkpoint to record SBI_NEED_FSCK.
>
> Signed-off-by: Zhiguo Niu <zhiguo.niu@xxxxxxxxxx>
> Signed-off-by: Chao Yu <chao@xxxxxxxxxx>
> ---
>   fs/f2fs/node.c          | 11 +++++++++--
>   include/linux/f2fs_fs.h |  1 +
>   2 files changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index a2b2c6c7f66d..57d9dd3a43bc 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -2389,7 +2389,7 @@ static int scan_nat_page(struct f2fs_sb_info *sbi,
>                 blk_addr = le32_to_cpu(nat_blk->entries[i].block_addr);
>
>                 if (blk_addr == NEW_ADDR)
> -                       return -EINVAL;
> +                       return -EFSCORRUPTED;
>
>                 if (blk_addr == NULL_ADDR) {
>                         add_free_nid(sbi, start_nid, true, true);
> @@ -2504,7 +2504,14 @@ static int __f2fs_build_free_nids(struct f2fs_sb_info *sbi,
>
>                         if (ret) {
>                                 f2fs_up_read(&nm_i->nat_tree_lock);
> -                               f2fs_err(sbi, "NAT is corrupt, run fsck to fix it");
> +
> +                               if (ret == -EFSCORRUPTED) {
> +                                       f2fs_err(sbi, "NAT is corrupt, run fsck to fix it");
> +                                       set_sbi_flag(sbi, SBI_NEED_FSCK);
> +                                       f2fs_handle_error(sbi,
> +                                                       ERROR_INCONSISTENT_NAT);
> +                               }
> +
>                                 return ret;
>                         }
>                 }
> diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
> index 07ed69c2840d..039fe0ce8d83 100644
> --- a/include/linux/f2fs_fs.h
> +++ b/include/linux/f2fs_fs.h
> @@ -104,6 +104,7 @@ enum f2fs_error {
>         ERROR_CORRUPTED_VERITY_XATTR,
>         ERROR_CORRUPTED_XATTR,
>         ERROR_INVALID_NODE_REFERENCE,
> +       ERROR_INCONSISTENT_NAT,
>         ERROR_MAX,
>   };
>
> --
> 2.40.1

Thank you for your updates and these updates are more reasonable based
on the latest code.
In addition,  I also modified the following code after I checked the
related flow of f2fs_handle_error.
ERROR_INCONSISTENT_FOOTER is reused here,   any suggestions for this?
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index d9e6087..94f5c7f 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1467,6 +1467,7 @@ static struct page *__get_node_page(struct
f2fs_sb_info *sbi, pgoff_t nid,
                          ofs_of_node(page), cpver_of_node(page),
                          next_blkaddr_of_node(page));
        set_sbi_flag(sbi, SBI_NEED_FSCK);
+       f2fs_handle_error(sbi, ERROR_INCONSISTENT_FOOTER);
        err = -EINVAL;
 out_err:
        ClearPageUptodate(page);

If you have no other suggestions, I will update the "PATCH V2"
Thanks!