From patchwork Fri Jul 27 08:01:06 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukas Czerner X-Patchwork-Id: 1247271 Return-Path: X-Original-To: patchwork-linux-mmc@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 31916DFFBF for ; Fri, 27 Jul 2012 08:03:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752538Ab2G0ICA (ORCPT ); Fri, 27 Jul 2012 04:02:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:63024 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752532Ab2G0IB6 (ORCPT ); Fri, 27 Jul 2012 04:01:58 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q6R81uJC010253 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 27 Jul 2012 04:01:56 -0400 Received: from vpn-10-43.rdu.redhat.com (vpn-10-43.rdu.redhat.com [10.11.10.43]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id q6R81SNQ013681; Fri, 27 Jul 2012 04:01:54 -0400 From: Lukas Czerner To: linux-fsdevel@vger.kernel.org Cc: linux-ext4@vger.kernel.org, tytso@mit.edu, hughd@google.com, linux-mmc@vger.kernel.org, Lukas Czerner Subject: [PATCH 07/15] ext4: Take i_mutex before punching hole Date: Fri, 27 Jul 2012 10:01:06 +0200 Message-Id: <1343376074-28034-8-git-send-email-lczerner@redhat.com> In-Reply-To: <1343376074-28034-1-git-send-email-lczerner@redhat.com> References: <1343376074-28034-1-git-send-email-lczerner@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 Sender: linux-mmc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org Currently the allocation might happen in the punched range after the truncation and before the releasing the space of the range. This would lead to blocks being unallocated under the mapped buffer heads resulting in nasty bugs. With this commit we take i_mutex before going to do anything in the ext4_ext_punch_hole() preventing any write to happen while the hole punching is in progress. This will also allow us to ditch the writeout of dirty pages withing the range. This commit was based on code provided by Zheng Liu, thanks! Signed-off-by: Lukas Czerner --- fs/ext4/extents.c | 26 ++++++++++---------------- 1 files changed, 10 insertions(+), 16 deletions(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 91341ec..2d6a216 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -4755,9 +4755,11 @@ int ext4_ext_punch_hole(struct file *file, loff_t offset, loff_t length) loff_t first_page_offset, last_page_offset; int credits, err = 0; + mutex_lock(&inode->i_mutex); + /* No need to punch hole beyond i_size */ if (offset >= inode->i_size) - return 0; + goto out1; /* * If the hole extends beyond i_size, set the hole @@ -4775,18 +4777,6 @@ int ext4_ext_punch_hole(struct file *file, loff_t offset, loff_t length) first_page_offset = first_page << PAGE_CACHE_SHIFT; last_page_offset = last_page << PAGE_CACHE_SHIFT; - /* - * Write out all dirty pages to avoid race conditions - * Then release them. - */ - if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { - err = filemap_write_and_wait_range(mapping, - offset, offset + length - 1); - - if (err) - return err; - } - /* Now release the pages */ if (last_page_offset > first_page_offset) { truncate_pagecache_range(inode, first_page_offset, @@ -4798,12 +4788,14 @@ int ext4_ext_punch_hole(struct file *file, loff_t offset, loff_t length) credits = ext4_writepage_trans_blocks(inode); handle = ext4_journal_start(inode, credits); - if (IS_ERR(handle)) - return PTR_ERR(handle); + if (IS_ERR(handle)) { + err = PTR_ERR(handle); + goto out1; + } err = ext4_orphan_add(handle, inode); if (err) - goto out; + goto out1; /* * Now we need to zero out the non-page-aligned data in the @@ -4893,6 +4885,8 @@ out: inode->i_mtime = inode->i_ctime = ext4_current_time(inode); ext4_mark_inode_dirty(handle, inode); ext4_journal_stop(handle); +out1: + mutex_unlock(&inode->i_mutex); return err; } int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,