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Date:   Tue, 7 Mar 2023 09:03:49 -0800
From:   Christoph Hellwig <hch@infradead.org>
To:     Goldwyn Rodrigues <rgoldwyn@suse.de>
Cc:     linux-btrfs@vger.kernel.org, Goldwyn Rodrigues <rgoldwyn@suse.com>,
        Johannes Thumshirn <johannes.thumshirn@wdc.com>,
        Josef Bacik <josef@toxicpanda.com>
Subject: Re: [PATCH 06/21] btrfs: wait ordered range before locking during
 truncate
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So, one thing I've been wondering about for a while is why btrfs even
does all these explicit waits for ordered extents.  The ordered_extent
is effectively a mechanism to describe a range of I/O.

So why can't we use the nornal mechanisms to wait for I/O, that is the
completion of writeback for buffered I/O (i.e. filemap_fdatawait*)
and inode_dio_wait for direct I/O?  I've been wanting to look deeper
into this for a while, so this might be a good time to bring it up.