From patchwork Sat Apr 1 06:35:02 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 9657525 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 9A2C860351 for ; Sat, 1 Apr 2017 06:36:26 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8BDBB286A2 for ; Sat, 1 Apr 2017 06:36:26 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7F1D1286C8; Sat, 1 Apr 2017 06:36:26 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0F7DC286A2 for ; Sat, 1 Apr 2017 06:36:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751394AbdDAGgZ (ORCPT ); Sat, 1 Apr 2017 02:36:25 -0400 Received: from bombadil.infradead.org ([65.50.211.133]:36123 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750881AbdDAGgY (ORCPT ); Sat, 1 Apr 2017 02:36:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=References:In-Reply-To:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=g6ETZGbuMf44Roqh8q8OB0+rLrMu07XBBtYOIvj/QUI=; b=Xq6kSBJTaWQVsdsoTp6LaqF0w d5ejTwHysK6jUImMCqAj3wtMC2Jw2uvXxmVqpwf6rchQ7Q74F5vL+AofkFJ7GcwSs6ZxKUsUSBLAF y6MoubaBvvor7VtIAi1y51ooyCmRitkMNRK/gjB5HFQa1zptGEqu7GHWKiAs211HSH7mdd9SidhSE thiQIfY7jknRTwMP0u8gE5ZTsEnJGXWHKqfTP4ewrIMC9RABMhbthwsiiAI1Yl8aOuObfaDTEpL2d zQcHN5MG3rVE2UoDNhXb4oXyzCUefScGIBVRrc6GJwSnFiYSYaLAwTg+KrZ/C2xzwgc0t0LrRGzqJ 8Va0t6qUA==; Received: from 77.117.150.49.wireless.dyn.drei.com ([77.117.150.49] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.87 #1 (Red Hat Linux)) id 1cuCe7-0000qy-EZ; Sat, 01 Apr 2017 06:36:24 +0000 From: Christoph Hellwig To: stable@vger.kernel.org Cc: linux-xfs@vger.kernel.org, Brian Foster , "Darrick J . Wong" Subject: [PATCH 16/26] xfs: handle indlen shortage on delalloc extent merge Date: Sat, 1 Apr 2017 08:35:02 +0200 Message-Id: <20170401063512.25313-17-hch@lst.de> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170401063512.25313-1-hch@lst.de> References: <20170401063512.25313-1-hch@lst.de> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Brian Foster commit 0e339ef8556d9e567aa7925f8892c263d79430d9 upstream. When a delalloc extent is created, it can be merged with pre-existing, contiguous, delalloc extents. When this occurs, xfs_bmap_add_extent_hole_delay() merges the extents along with the associated indirect block reservations. The expectation here is that the combined worst case indlen reservation is always less than or equal to the indlen reservation for the individual extents. This is not always the case, however, as existing extents can less than the expected indlen reservation if the extent was previously split due to a hole punch. If a new extent merges with such an extent, the total indlen requirement may be larger than the sum of the indlen reservations held by both extents. xfs_bmap_add_extent_hole_delay() assumes that the worst case indlen reservation is always available and assigns it to the merged extent without consideration for the indlen held by the pre-existing extent. As a result, the subsequent xfs_mod_fdblocks() call can attempt an unintentional allocation rather than a free (indicated by an ASSERT() failure). Further, if the allocation happens to fail in this context, the failure goes unhandled and creates a filesystem wide block accounting inconsistency. Fix xfs_bmap_add_extent_hole_delay() to function as designed. Cap the indlen reservation assigned to the merged extent to the sum of the indlen reservations held by each of the individual extents. Signed-off-by: Brian Foster Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/libxfs/xfs_bmap.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c index 5b626a4f1d13..6eb9ae8ed22d 100644 --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -2816,7 +2816,8 @@ xfs_bmap_add_extent_hole_delay( oldlen = startblockval(left.br_startblock) + startblockval(new->br_startblock) + startblockval(right.br_startblock); - newlen = xfs_bmap_worst_indlen(ip, temp); + newlen = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp), + oldlen); xfs_bmbt_set_startblock(xfs_iext_get_ext(ifp, *idx), nullstartblock((int)newlen)); trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_); @@ -2837,7 +2838,8 @@ xfs_bmap_add_extent_hole_delay( xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, *idx), temp); oldlen = startblockval(left.br_startblock) + startblockval(new->br_startblock); - newlen = xfs_bmap_worst_indlen(ip, temp); + newlen = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp), + oldlen); xfs_bmbt_set_startblock(xfs_iext_get_ext(ifp, *idx), nullstartblock((int)newlen)); trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_); @@ -2853,7 +2855,8 @@ xfs_bmap_add_extent_hole_delay( temp = new->br_blockcount + right.br_blockcount; oldlen = startblockval(new->br_startblock) + startblockval(right.br_startblock); - newlen = xfs_bmap_worst_indlen(ip, temp); + newlen = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp), + oldlen); xfs_bmbt_set_allf(xfs_iext_get_ext(ifp, *idx), new->br_startoff, nullstartblock((int)newlen), temp, right.br_state);