Re: [PATCH 02/14] fs: lift the FMODE_NOCMTIME check into file_update_time_flags

Jan Kara
2025-11-24T11:54:43Z

On Fri 14-11-25 07:26:05, Christoph Hellwig wrote:
> FMODE_NOCMTIME used to be just a hack for the legacy XFS handle-based
> "invisible I/O", but commit e5e9b24ab8fa ("nfsd: freeze c/mtime updates
> with outstanding WRITE_ATTRS delegation") started using it from
> generic callers.
>
> I'm not sure other file systems are actually read for this in general,
^^ ready

> so the above commit should get a closer look, but for it to make any
> sense, file_update_time needs to respect the flag.
>
> Lift the check from file_modified_flags to file_update_time so that
> users of file_update_time inherit the behavior and so that all the
> checks are done in one place.
>
> Fixes: e5e9b24ab8fa ("nfsd: freeze c/mtime updates with outstanding WRITE_ATTRS delegation")
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reagrdless whether FMODE_NOCMTIME works properly for all filesystems this
looks like a sensible step so feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

Honza

> ---
> fs/inode.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/inode.c b/fs/inode.c
> index 4884ffa931e7..24dab63844db 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -2320,6 +2320,8 @@ static int file_update_time_flags(struct file *file, unsigned int flags)
> /* First try to exhaust all avenues to not sync */
> if (IS_NOCMTIME(inode))
> return 0;
> + if (unlikely(file->f_mode & FMODE_NOCMTIME))
> + return 0;
>
> now = current_time(inode);
>
> @@ -2391,8 +2393,6 @@ static int file_modified_flags(struct file *file, int flags)
> ret = file_remove_privs_flags(file, flags);
> if (ret)
> return ret;
> - if (unlikely(file->f_mode & FMODE_NOCMTIME))
> - return 0;
> return file_update_time_flags(file, flags);
> }
>
> --
> 2.47.3
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR