From patchwork Fri Aug 7 07:05:52 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chandan Rajendra X-Patchwork-Id: 6965341 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 45A27C05AC for ; Fri, 7 Aug 2015 07:07:54 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 34CC62066F for ; Fri, 7 Aug 2015 07:07:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 23BBD20666 for ; Fri, 7 Aug 2015 07:07:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755210AbbHGHHt (ORCPT ); Fri, 7 Aug 2015 03:07:49 -0400 Received: from e23smtp03.au.ibm.com ([202.81.31.145]:38308 "EHLO e23smtp03.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754881AbbHGHH0 (ORCPT ); Fri, 7 Aug 2015 03:07:26 -0400 Received: from /spool/local by e23smtp03.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Fri, 7 Aug 2015 17:07:23 +1000 X-Helo: d23dlp02.au.ibm.com X-MailFrom: chandan@linux.vnet.ibm.com X-RcptTo: linux-btrfs@vger.kernel.org Received: from d23relay06.au.ibm.com (d23relay06.au.ibm.com [9.185.63.219]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 6295F2BB005E for ; Fri, 7 Aug 2015 17:07:23 +1000 (EST) Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay06.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t7777Euv34603184 for ; Fri, 7 Aug 2015 17:07:22 +1000 Received: from d23av02.au.ibm.com (localhost [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t7776ojp032025 for ; Fri, 7 Aug 2015 17:06:51 +1000 Received: from localhost.in.ibm.com ([9.124.35.223]) by d23av02.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id t7776ds8031165; Fri, 7 Aug 2015 17:06:48 +1000 From: Chandan Rajendra To: linux-btrfs@vger.kernel.org Cc: Chandan Rajendra , clm@fb.com, jbacik@fb.com, bo.li.liu@oracle.com, dsterba@suse.cz, chandan@mykolab.com, quwenruo@cn.fujitsu.com Subject: [PATCH V2 05/11] Btrfs: btrfs_page_mkwrite: Reserve space in sectorsized units Date: Fri, 7 Aug 2015 12:35:52 +0530 Message-Id: <1438931158-20888-6-git-send-email-chandan@linux.vnet.ibm.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1438931158-20888-1-git-send-email-chandan@linux.vnet.ibm.com> References: <1438931158-20888-1-git-send-email-chandan@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15080707-0009-0000-0000-000001DC6CA8 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Spam-Status: No, score=-7.0 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In subpagesize-blocksize scenario, if i_size occurs in a block which is not the last block in the page, then the space to be reserved should be calculated appropriately. Reviewed-by: Liu Bo Signed-off-by: Chandan Rajendra --- fs/btrfs/inode.c | 36 +++++++++++++++++++++++++++++++----- 1 file changed, 31 insertions(+), 5 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index afb8d2b..b39273b 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -8626,11 +8626,24 @@ int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) loff_t size; int ret; int reserved = 0; + u64 reserved_space; u64 page_start; u64 page_end; + u64 end; + + reserved_space = PAGE_CACHE_SIZE; sb_start_pagefault(inode->i_sb); - ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE); + + /* + Reserving delalloc space after obtaining the page lock can lead to + deadlock. For example, if a dirty page is locked by this function + and the call to btrfs_delalloc_reserve_space() ends up triggering + dirty page write out, then the btrfs_writepage() function could + end up waiting indefinitely to get a lock on the page currently + being processed by btrfs_page_mkwrite() function. + */ + ret = btrfs_delalloc_reserve_space(inode, reserved_space); if (!ret) { ret = file_update_time(vma->vm_file); reserved = 1; @@ -8651,6 +8664,7 @@ again: size = i_size_read(inode); page_start = page_offset(page); page_end = page_start + PAGE_CACHE_SIZE - 1; + end = page_end; if ((page->mapping != inode->i_mapping) || (page_start >= size)) { @@ -8666,7 +8680,7 @@ again: * we can't set the delalloc bits if there are pending ordered * extents. Drop our locks and wait for them to finish */ - ordered = btrfs_lookup_ordered_extent(inode, page_start); + ordered = btrfs_lookup_ordered_range(inode, page_start, page_end); if (ordered) { unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS); @@ -8676,6 +8690,18 @@ again: goto again; } + if (page->index == ((size - 1) >> PAGE_CACHE_SHIFT)) { + reserved_space = round_up(size - page_start, root->sectorsize); + if (reserved_space < PAGE_CACHE_SIZE) { + end = page_start + reserved_space - 1; + spin_lock(&BTRFS_I(inode)->lock); + BTRFS_I(inode)->outstanding_extents++; + spin_unlock(&BTRFS_I(inode)->lock); + btrfs_delalloc_release_space(inode, + PAGE_CACHE_SIZE - reserved_space); + } + } + /* * XXX - page_mkwrite gets called every time the page is dirtied, even * if it was already dirty, so for space accounting reasons we need to @@ -8683,12 +8709,12 @@ again: * is probably a better way to do this, but for now keep consistent with * prepare_pages in the normal write path. */ - clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end, + clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, end, EXTENT_DIRTY | EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 0, 0, &cached_state, GFP_NOFS); - ret = btrfs_set_extent_delalloc(inode, page_start, page_end, + ret = btrfs_set_extent_delalloc(inode, page_start, end, &cached_state); if (ret) { unlock_extent_cached(io_tree, page_start, page_end, @@ -8727,7 +8753,7 @@ out_unlock: } unlock_page(page); out: - btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE); + btrfs_delalloc_release_space(inode, reserved_space); out_noreserve: sb_end_pagefault(inode->i_sb); return ret;