linux-kernel - Re: [PATCH] xfs: return when delta equals 0 in xfs_mod

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Message-ID: <20220621043550.GP227878@dread.disaster.area>
Date:   Tue, 21 Jun 2022 14:35:50 +1000
From:   Dave Chinner <david@...morbit.com>
To:     Shida Zhang <starzhangzsd@...il.com>
Cc:     djwong@...nel.org, zhangshida@...inos.cn,
        linux-kernel@...r.kernel.org, linux-xfs@...r.kernel.org
Subject: Re: [PATCH] xfs: return when delta equals 0 in xfs_mod_freecounter

On Tue, Jun 21, 2022 at 11:11:13AM +0800, Shida Zhang wrote:
> There are cases that xfs_mod_freecounter() will get called when delta
> equals 0 while it's unnecessary.

AFAICT all of the call paths are guarded by checks to ensure the
delta is, in fact, not zero. i.e. if the delta is zero, we shouldn't
be calling xfs_mod_fdblocks() or xfs_mod_frextents() at all.

Can you explain in more detail what code path leads to delta = 0
here?

Cheers,

Dave.
-- 
Dave Chinner
david@...morbit.com