From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vyacheslav Dubeyko Subject: Re: [PATCH v2] nilfs2: remove double bio_put() in nilfs_end_bio_write() for BIO_EOPNOTSUPP error Date: Wed, 31 Jul 2013 14:36:47 +0400 Message-ID: <1375267007.2364.7.camel@slavad-ubuntu> References: <1374847154.3671.70.camel@slavad-ubuntu> <20130727.120232.356926182.konishi.ryusuke@lab.ntt.co.jp> Reply-To: slava@dubeyko.com Mime-Version: 1.0 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=dubeyko.com; s=default; h=Mime-Version:Content-Transfer-Encoding:Content-Type:References:In-Reply-To:Date:Cc:To:Reply-To:From:Subject:Message-ID; bh=uwGONRCaDS96jsXS/I/a2xDUBjfY6wQtPB7Xi7n7JtM=; b=fwqsvTUpqRaTpq2DunJ8rEFiXgDxi9Bc1tmOLEVi9J+kI+NbLwr19fg0cwf9BN/2RzXLYQyUixu6ew9aIX7Dwb/aEMVlmkp8+tRAHUfYTJ/+cXoTppTgljOiZrf3EnAQ; In-Reply-To: <20130727.120232.356926182.konishi.ryusuke@lab.ntt.co.jp> Sender: kernel-janitors-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="utf-8" To: Ryusuke Konishi Cc: DanCarpenter , linux-nilfs , Linux FS Devel , kernel-janitors@vger.kernel.org, akpm@linux-foundation.org, =?ISO-8859-1?Q?J=E9r=F4me?= Poulin Hi Ryusuke, On Sat, 2013-07-27 at 12:02 +0900, Ryusuke Konishi wrote: [snip] >=20 > This decrement looks wrong. >=20 > Otherwise, your change of nilfs_segbuf_submit_bio() is just a > equivalent transformation and doesn't fix problem, that is, a mismatc= h > of the number of calls between complete() and wait_for_completion(). >=20 > In your patch, nilfs_end_bio_write() function calls the complete() > routine as before even if it received an EOPNOTSUPP error. >=20 > In that case, segbuf->sb_nbio must be incremented to call > wait_for_completion() the right number of times. >=20 > Note that wait_for_completion() is called based on the count of > segbuf->sb_nbio even if nilfs_segbuf_submit_bio() returns an error. > This is performed through the following path: >=20 > nilfs_segbuf_submit_bio > nilfs_segbuf_submit_bh > nilfs_segbuf_write > nilfs_write_logs > nilfs_segctor_write > nilfs_segctor_do_construct > nilfs_segctor_abort_construction > nilfs_wait_on_logs > nilfs_segbuf_wait > wait_for_completion > (repeated for the number of times of segbuf->sb_nbio) >=20 >=20 > If you think this is a separate problem, then it should be fixed in > another patch and nilfs_segbuf_submit_bio() should not be touched in > this patch. >=20 Sorry for delay with working on this patch. Now I am investigating the issue (Kernel Bug: unable to handle kernel paging request) that it was reported by J=C3=A9r=C3=B4me Poulin . I sus= pect that the reported issue is related to this patch. So, I feel a necessity to investigate the issue more deeply before continuation to work on this patch. With the best regards, Vyacheslav Dubeyko. -- To unsubscribe from this list: send the line "unsubscribe kernel-janito= rs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html