Re: [f2fs-dev] [PATCH 2/2] f2fs: truncate page cache before clearing flags when aborting atomic write

[Daeho Jeong]

Reviewed-by: Daeho Jeong <daehojeong@xxxxxxxxxx>

On Wed, Mar 13, 2024 at 4:29 AM Sunmin Jeong <s_min.jeong@xxxxxxxxxxx> wrote:
>
> In f2fs_do_write_data_page, FI_ATOMIC_FILE flag selects the target inode
> between the original inode and COW inode. When aborting atomic write and
> writeback occur simultaneously, invalid data can be written to original
> inode if the FI_ATOMIC_FILE flag is cleared meanwhile.
>
> To prevent the problem, let's truncate all pages before clearing the flag
>
> Atomic write thread              Writeback thread
>   f2fs_abort_atomic_write
>     clear_inode_flag(inode, FI_ATOMIC_FILE)
>                                   __writeback_single_inode
>                                     do_writepages
>                                       f2fs_do_write_data_page
>                                         - use dn of original inode
>     truncate_inode_pages_final
>
> Fixes: 3db1de0e582c ("f2fs: change the current atomic write way")
> Cc: stable@xxxxxxxxxxxxxxx #v5.19+
> Reviewed-by: Sungjong Seo <sj1557.seo@xxxxxxxxxxx>
> Reviewed-by: Yeongjin Gil <youngjin.gil@xxxxxxxxxxx>
> Signed-off-by: Sunmin Jeong <s_min.jeong@xxxxxxxxxxx>
> ---
>  fs/f2fs/segment.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 7901ede58113..7e47b8054413 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -192,6 +192,9 @@ void f2fs_abort_atomic_write(struct inode *inode, bool clean)
>         if (!f2fs_is_atomic_file(inode))
>                 return;
>
> +       if (clean)
> +               truncate_inode_pages_final(inode->i_mapping);
> +
>         release_atomic_write_cnt(inode);
>         clear_inode_flag(inode, FI_ATOMIC_COMMITTED);
>         clear_inode_flag(inode, FI_ATOMIC_REPLACE);
> @@ -201,7 +204,6 @@ void f2fs_abort_atomic_write(struct inode *inode, bool clean)
>         F2FS_I(inode)->atomic_write_task = NULL;
>
>         if (clean) {
> -               truncate_inode_pages_final(inode->i_mapping);
>                 f2fs_i_size_write(inode, fi->original_i_size);
>                 fi->original_i_size = 0;
>         }
> --
> 2.25.1
>
>
>
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