From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B6BA5C4363A for ; Thu, 8 Oct 2020 11:00:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3B41F215A4 for ; Thu, 8 Oct 2020 11:00:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="eCd7k2Ss" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729722AbgJHLAb (ORCPT ); Thu, 8 Oct 2020 07:00:31 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:55052 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726555AbgJHLA0 (ORCPT ); Thu, 8 Oct 2020 07:00:26 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 098B0DL9124157; Thu, 8 Oct 2020 11:00:20 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=corp-2020-01-29; bh=pj1XfLnhrDsQrvUSb3kVB7Bjt2ZsQhIi1K4cKWj8pAY=; b=eCd7k2SspEtEt6Xmgou7wZhOi6q00/Qq4PfaqeeDtoFmiSNEM8Jk56BFyNAo9DqCGHP0 yFsz+Z9UQk4/UmeA3V+EtpMBY9Blt4Yeo2JXPNaju9WFFfDsyIbD5nZnmAC5xEKyzKRr iQxrpKgEdzakpWpYNDA2Og8B53HfjZ7tKCqNCPw2oKSmtVJziyzb3Mkb6WbUKL593WIQ eO1FX/md0H1JTMTF7BFsJ3R+mCKnjDhr/7um1X4iYcKLydvim0nsY5hoFfPLsf39GZIc C4K14P0L9q0RAKzxdOSbQjuggSXxDM89K2qxXz9ou4gefj3eHT2mUA4mlQu+KlsQAwzR SQ== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2120.oracle.com with ESMTP id 33xhxn6x23-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 08 Oct 2020 11:00:20 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 098AuEZW188488; Thu, 8 Oct 2020 11:00:20 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userp3030.oracle.com with ESMTP id 33y380yvjj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 08 Oct 2020 11:00:20 +0000 Received: from abhmp0013.oracle.com (abhmp0013.oracle.com [141.146.116.19]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 098B0J32023495; Thu, 8 Oct 2020 11:00:19 GMT Received: from ltp.sg.oracle.com (/10.191.35.225) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 08 Oct 2020 04:00:19 -0700 From: Anand Jain To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: wqu@suse.com, fdmanana@suse.com, dsterba@suse.com, linux-btrfs@vger.kernel.org Subject: [PATCH stable-5.4 6/6] btrfs: allow btrfs_truncate_block() to fallback to nocow for data space reservation Date: Thu, 8 Oct 2020 18:59:54 +0800 Message-Id: <9df7b36688030028271fe5d4265512328534f9b6.1599750901.git.anand.jain@oracle.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9767 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 malwarescore=0 suspectscore=2 adultscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2010080081 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9767 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 malwarescore=0 bulkscore=0 impostorscore=0 lowpriorityscore=0 suspectscore=2 phishscore=0 mlxlogscore=999 adultscore=0 clxscore=1015 spamscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2010080081 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org From: Qu Wenruo commit 6d4572a9d71d5fc2affee0258d8582d39859188c upstream. [BUG] When the data space is exhausted, even if the inode has NOCOW attribute, we will still refuse to truncate unaligned range due to ENOSPC. The following script can reproduce it pretty easily: #!/bin/bash dev=/dev/test/test mnt=/mnt/btrfs umount $dev &> /dev/null umount $mnt &> /dev/null mkfs.btrfs -f $dev -b 1G mount -o nospace_cache $dev $mnt touch $mnt/foobar chattr +C $mnt/foobar xfs_io -f -c "pwrite -b 4k 0 4k" $mnt/foobar > /dev/null xfs_io -f -c "pwrite -b 4k 0 1G" $mnt/padding &> /dev/null sync xfs_io -c "fpunch 0 2k" $mnt/foobar umount $mnt Currently this will fail at the fpunch part. [CAUSE] Because btrfs_truncate_block() always reserves space without checking the NOCOW attribute. Since the writeback path follows NOCOW bit, we only need to bother the space reservation code in btrfs_truncate_block(). [FIX] Make btrfs_truncate_block() follow btrfs_buffered_write() to try to reserve data space first, and fall back to NOCOW check only when we don't have enough space. Such always-try-reserve is an optimization introduced in btrfs_buffered_write(), to avoid expensive btrfs_check_can_nocow() call. This patch will export check_can_nocow() as btrfs_check_can_nocow(), and use it in btrfs_truncate_block() to fix the problem. Reported-by: Martin Doucha Reviewed-by: Filipe Manana Reviewed-by: Anand Jain Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Anand Jain Conflicts: fs/btrfs/ctree.h fs/btrfs/file.c fs/btrfs/inode.c --- fs/btrfs/ctree.h | 2 ++ fs/btrfs/file.c | 9 +++++---- fs/btrfs/inode.c | 44 +++++++++++++++++++++++++++++++++++++------- 3 files changed, 44 insertions(+), 11 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 9a690c10afaa..23b4f38e2392 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -2956,6 +2956,8 @@ int btrfs_fdatawrite_range(struct inode *inode, loff_t start, loff_t end); loff_t btrfs_remap_file_range(struct file *file_in, loff_t pos_in, struct file *file_out, loff_t pos_out, loff_t len, unsigned int remap_flags); +int btrfs_check_can_nocow(struct btrfs_inode *inode, loff_t pos, + size_t *write_bytes); /* tree-defrag.c */ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans, diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 4d0e1f9452a5..4126513e2429 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1546,8 +1546,8 @@ lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page **pages, return ret; } -static noinline int check_can_nocow(struct btrfs_inode *inode, loff_t pos, - size_t *write_bytes) +int btrfs_check_can_nocow(struct btrfs_inode *inode, loff_t pos, + size_t *write_bytes) { struct btrfs_fs_info *fs_info = inode->root->fs_info; struct btrfs_root *root = inode->root; @@ -1647,7 +1647,7 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb, if (ret < 0) { if ((BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC)) && - check_can_nocow(BTRFS_I(inode), pos, + btrfs_check_can_nocow(BTRFS_I(inode), pos, &write_bytes) > 0) { /* * For nodata cow case, no need to reserve @@ -1927,7 +1927,8 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb, */ if (!(BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC)) || - check_can_nocow(BTRFS_I(inode), pos, &nocow_bytes) <= 0) { + btrfs_check_can_nocow(BTRFS_I(inode), pos, + &nocow_bytes) <= 0) { inode_unlock(inode); return -EAGAIN; } diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 9ac40991a640..2356b28afebe 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -5133,11 +5133,13 @@ int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len, struct extent_state *cached_state = NULL; struct extent_changeset *data_reserved = NULL; char *kaddr; + bool only_release_metadata = false; u32 blocksize = fs_info->sectorsize; pgoff_t index = from >> PAGE_SHIFT; unsigned offset = from & (blocksize - 1); struct page *page; gfp_t mask = btrfs_alloc_write_mask(mapping); + size_t write_bytes = blocksize; int ret = 0; u64 block_start; u64 block_end; @@ -5149,11 +5151,27 @@ int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len, block_start = round_down(from, blocksize); block_end = block_start + blocksize - 1; - ret = btrfs_delalloc_reserve_space(inode, &data_reserved, - block_start, blocksize); - if (ret) - goto out; + ret = btrfs_check_data_free_space(inode, &data_reserved, block_start, + blocksize); + if (ret < 0) { + if ((BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | + BTRFS_INODE_PREALLOC)) && + btrfs_check_can_nocow(BTRFS_I(inode), block_start, + &write_bytes) > 0) { + /* For nocow case, no need to reserve data space */ + only_release_metadata = true; + } else { + goto out; + } + } + ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), blocksize); + if (ret < 0) { + if (!only_release_metadata) + btrfs_free_reserved_data_space(inode, data_reserved, + block_start, blocksize); + goto out; + } again: page = find_or_create_page(mapping, index, mask); if (!page) { @@ -5222,14 +5240,26 @@ int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len, set_page_dirty(page); unlock_extent_cached(io_tree, block_start, block_end, &cached_state); + if (only_release_metadata) + set_extent_bit(&BTRFS_I(inode)->io_tree, block_start, + block_end, EXTENT_NORESERVE, NULL, NULL, + GFP_NOFS); + out_unlock: - if (ret) - btrfs_delalloc_release_space(inode, data_reserved, block_start, - blocksize, true); + if (ret) { + if (only_release_metadata) + btrfs_delalloc_release_metadata(BTRFS_I(inode), + blocksize, true); + else + btrfs_delalloc_release_space(inode, data_reserved, + block_start, blocksize, true); + } btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize); unlock_page(page); put_page(page); out: + if (only_release_metadata) + btrfs_end_write_no_snapshotting(BTRFS_I(inode)->root); extent_changeset_free(data_reserved); return ret; } -- 2.25.1