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From: Qu Wenruo <wqu@suse.de>
To: "linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	Linux FS Devel <linux-fsdevel@vger.kernel.org>
Subject: About `bio->bi_iter.bi_size` at write endio time
Date: Tue, 15 Jun 2021 15:22:59 +0800	[thread overview]
Message-ID: <18cbcd0b-8c49-00b8-558b-5d74b3664b85@suse.de> (raw)

Hi,

Recently I got a strange case where for write bio, at its endio time, I 
got bio->bi_iter.bi_size == 0, but bio_for_each_segment_all() reports we 
still have some bv_len.

And obviously, when the bio get submitted, its bi_size is not 0.

This is especially common for REQ_OP_ZONE_APPEND bio, but I also get 
rare bi_size == 0 at endio time, for REQ_OP_WRITE too.

So I guess bi_size at endio time is no longer reliable due to bio 
merging/splitting?

Thus the only correct way to get how large a bio really is, is through 
bio_for_each_segment_all()?

Thanks,
Qu

             reply	other threads:[~2021-06-15  7:23 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-15  7:22 Qu Wenruo [this message]
2021-06-15  8:37 ` About `bio->bi_iter.bi_size` at write endio time Ming Lei

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