From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7D85313A3EC; Wed, 18 Sep 2024 05:15:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.95.11.211 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726636529; cv=none; b=COinpf9IY/koBZcS8/mWcUeL1HDL/DPqheXesavkkBxY+jCZMO7E1woa8DgBXzdS2AMfOqx9RuI/6C1NyVBHpGAOmRQTdKn9egbbi9wsavqGl0qP3YcrC103YGxc4loNRZ4MlH+0YIGaVYU0b61Zkl5duL1NGCjGDq9FZf3/BHo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726636529; c=relaxed/simple; bh=CwxHztH+gWBZMyLxch/dTrF/ZYXcuboyr07EfNJR1ro=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=OOiQ4aVjvZg1aVA4UY83U9dVuH5Puy3UYK5gYjIYuXHxJ7D3Pm/w47WtiThMcibgVdda7FNrmyivPIB5fd0DJeivoJYW24M6LEENMgBebl08g3dGNuKfYFr3BuPwp/poS2Y2gRpz1hAfGh/AlywJhYgMLS6Cm4S9u0oUAud3lfI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de; spf=pass smtp.mailfrom=lst.de; arc=none smtp.client-ip=213.95.11.211 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lst.de Received: by verein.lst.de (Postfix, from userid 2407) id 64C66227AB6; Wed, 18 Sep 2024 07:15:23 +0200 (CEST) Date: Wed, 18 Sep 2024 07:15:23 +0200 From: Christoph Hellwig To: "Darrick J. Wong" Cc: Christoph Hellwig , Chandan Babu R , Christian Brauner , linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 08/12] iomap: zeroing already holds invalidate_lock Message-ID: <20240918051523.GC31238@lst.de> References: <20240910043949.3481298-1-hch@lst.de> <20240910043949.3481298-9-hch@lst.de> <20240917212935.GE182177@frogsfrogsfrogs> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240917212935.GE182177@frogsfrogsfrogs> User-Agent: Mutt/1.5.17 (2007-11-01) On Tue, Sep 17, 2024 at 02:29:35PM -0700, Darrick J. Wong wrote: > On Tue, Sep 10, 2024 at 07:39:10AM +0300, Christoph Hellwig wrote: > > All callers of iomap_zero_range already hold invalidate_lock, so we can't > > take it again in iomap_file_buffered_write_punch_delalloc. > > > > Use the passed in flags argument to detect if we're called from a zeroing > > operation and don't take the lock again in this case. > > > > Signed-off-by: Christoph Hellwig > > --- > > fs/iomap/buffered-io.c | 10 ++++++++-- > > 1 file changed, 8 insertions(+), 2 deletions(-) > > > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > > index 52f285ae4bddcb..3d7e69a542518a 100644 > > --- a/fs/iomap/buffered-io.c > > +++ b/fs/iomap/buffered-io.c > > @@ -1188,8 +1188,13 @@ static void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte, > > * folios and dirtying them via ->page_mkwrite whilst we walk the > > * cache and perform delalloc extent removal. Failing to do this can > > * leave dirty pages with no space reservation in the cache. > > + * > > + * For zeroing operations the callers already hold invalidate_lock. > > */ > > - filemap_invalidate_lock(inode->i_mapping); > > + if (flags & IOMAP_ZERO) > > + rwsem_assert_held_write(&inode->i_mapping->invalidate_lock); > > Does the other iomap_zero_range user (gfs2) take the invalidate lock? > AFAICT it doesn't. Shouldn't we annotate iomap_zero_range to say that > callers have to hold i_rwsem and the invalidate_lock? gfs2 does not hold invalidate_lock over iomap_zero_range. But it also does not use iomap_file_buffered_write_punch_delalloc at all, which is what requires the lock (and asserts that it is held).