linux-ext4 - Re: [PATCH 29/31] ext4: reserve space for xattr entries/names

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Date:   Wed, 14 Jun 2017 16:39:37 -0700
From:   Tahsin Erdogan <tahsin@...gle.com>
To:     "Darrick J. Wong" <darrick.wong@...cle.com>
Cc:     Jan Kara <jack@...e.com>, "Theodore Ts'o" <tytso@....edu>,
        Andreas Dilger <adilger.kernel@...ger.ca>,
        Dave Kleikamp <shaggy@...nel.org>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Mark Fasheh <mfasheh@...sity.com>,
        Joel Becker <jlbec@...lplan.org>, Jens Axboe <axboe@...com>,
        Deepa Dinamani <deepa.kernel@...il.com>,
        Mike Christie <mchristi@...hat.com>,
        Fabian Frederick <fabf@...net.be>, linux-ext4@...r.kernel.org,
        linux-kernel@...r.kernel.org, jfs-discussion@...ts.sourceforge.net,
        linux-fsdevel@...r.kernel.org, ocfs2-devel@....oracle.com,
        reiserfs-devel@...r.kernel.org
Subject: Re: [PATCH 29/31] ext4: reserve space for xattr entries/names

On Wed, Jun 14, 2017 at 4:05 PM, Darrick J. Wong
<darrick.wong@...cle.com> wrote:
> Why not just spill the values into their own ea_inodes if we need the
> space?  I guess that has the disadvantage that now we need to reserve
> quite a few more journal credits ((1 inode block, 1 bbitmap block, 1
> ibitmap block, 1 data block) * nr_inline_values) just in case we end up
> spilling all the values.
>

In last week's ext4 conference call we have discussed this problem and
possible solutions. The major concern with spilling/evacuation
approach was the added complexity. We haven't discussed the impact on
journal credits, but that is a valid point too.