linux-kernel - Re: [PATCH 05/11] fs: refactor ->update

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Message-ID: <jlw4ghr5vx32ss576akxes25oodlcx42zak7vjaaktlgn3m3d7@cbpcvx66y7za>
Date: Tue, 6 Jan 2026 12:48:47 +0100
From: Jan Kara <jack@...e.cz>
To: Christoph Hellwig <hch@....de>
Cc: Christian Brauner <brauner@...nel.org>, 
	Al Viro <viro@...iv.linux.org.uk>, David Sterba <dsterba@...e.com>, Jan Kara <jack@...e.cz>, 
	Mike Marshall <hubcap@...ibond.com>, Martin Brandenburg <martin@...ibond.com>, 
	Carlos Maiolino <cem@...nel.org>, Stefan Roesch <shr@...com>, Jeff Layton <jlayton@...nel.org>, 
	OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>, Trond Myklebust <trondmy@...nel.org>, 
	Anna Schumaker <anna@...nel.org>, linux-kernel@...r.kernel.org, linux-btrfs@...r.kernel.org, 
	linux-fsdevel@...r.kernel.org, gfs2@...ts.linux.dev, io-uring@...r.kernel.org, 
	devel@...ts.orangefs.org, linux-unionfs@...r.kernel.org, linux-mtd@...ts.infradead.org, 
	linux-xfs@...r.kernel.org, linux-nfs@...r.kernel.org
Subject: Re: [PATCH 05/11] fs: refactor ->update_time handling

On Tue 06-01-26 08:49:59, Christoph Hellwig wrote:
> Pass the type of update (atime vs c/mtime plus version) as an enum
> instead of a set of flags that caused all kinds of confusion.
> Because inode_update_timestamps now can't return a modified version
> of those flags, return the I_DIRTY_* flags needed to persist the
> update, which is what the main caller in generic_update_time wants
> anyway, and which is suitable for the other callers that only want
> to know if an update happened.
> 
> The whole update_time path keeps the flags argument, which will be used
> to support non-blocking updates soon even if it is unused, and (the
> slightly renamed) inode_update_time also gains the possibility to return
> a negative errno to support this.
> 
> Signed-off-by: Christoph Hellwig <hch@....de>

...

> +static int inode_update_cmtime(struct inode *inode)
> +{
> +	struct timespec64 now = inode_set_ctime_current(inode);

This needs to be below sampling of ctime. Otherwise inode dirtying will be
broken...

> +	struct timespec64 ctime = inode_get_ctime(inode);
> +	struct timespec64 mtime = inode_get_mtime(inode);
> +	unsigned int dirty = 0;
> +	bool mtime_changed;
> +
> +	mtime_changed = !timespec64_equal(&now, &mtime);
> +	if (mtime_changed || !timespec64_equal(&now, &ctime))
> +		dirty = inode_time_dirty_flag(inode);
> +	if (mtime_changed)
> +		inode_set_mtime_to_ts(inode, now);
> +
> +	if (IS_I_VERSION(inode) && inode_maybe_inc_iversion(inode, !!dirty))
> +		dirty |= I_DIRTY_SYNC;
> +
> +	return dirty;
> +}

Otherwise the patch looks good to me.

								Honza

-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR