From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([59.151.112.132]:21277 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751305AbdEQBTZ (ORCPT ); Tue, 16 May 2017 21:19:25 -0400 Subject: Re: [RFC PATCH v3.1 3/6] btrfs: qgroup: Return actually freed bytes for qgroup release or free data From: Qu Wenruo To: , , References: <20170512033046.31981-1-quwenruo@cn.fujitsu.com> <20170512033046.31981-4-quwenruo@cn.fujitsu.com> <20170516142306.GE4065@twin.jikos.cz> Message-ID: <21582e1d-6162-6a2c-762a-6bf3f6e62a63@cn.fujitsu.com> Date: Wed, 17 May 2017 09:19:17 +0800 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: At 05/17/2017 09:12 AM, Qu Wenruo wrote: > > > At 05/16/2017 10:23 PM, David Sterba wrote: >> On Fri, May 12, 2017 at 11:30:43AM +0800, Qu Wenruo wrote: >>> btrfs_qgroup_release/free_data() only returns 0 or minus error >>> number(ENOMEM is the only possible error). >> >> "btrfs_qgroup_release/free_data() only returns 0 or a negative error >> number (ENOMEM is the only possible error)." > >>> This is normally good enough, but sometimes we need the accurate byte >>> number it freed/released. >>> >>> Change it to return actually released/freed bytenr number instead of 0 >>> for success. >>> And slightly modify related extent_changeset structure, since in btrfs >>> one none-hole data extent won't be larger than 128M, so "unsigned int" >> ^^^^^^^^^ >> NO_HOLES or no-hole >> >>> is large enough for the use case. >>> >>> Signed-off-by: Qu Wenruo >>> --- >>> fs/btrfs/extent-tree.c | 2 +- >>> fs/btrfs/extent_io.h | 2 +- >>> fs/btrfs/qgroup.c | 1 + >>> 3 files changed, 3 insertions(+), 2 deletions(-) >>> >>> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c >>> index e390451c72e6..4f62696131a6 100644 >>> --- a/fs/btrfs/extent-tree.c >>> +++ b/fs/btrfs/extent-tree.c >>> @@ -4298,7 +4298,7 @@ int btrfs_check_data_free_space(struct inode >>> *inode, u64 start, u64 len) >>> /* Use new btrfs_qgroup_reserve_data to reserve precious data >>> space. */ >>> ret = btrfs_qgroup_reserve_data(inode, start, len); >>> - if (ret) >>> + if (ret < 0) >>> btrfs_free_reserved_data_space_noquota(inode, start, len); >>> return ret; >>> } >>> diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h >>> index 1eafa2f0ede3..cc1b08fa9fe7 100644 >>> --- a/fs/btrfs/extent_io.h >>> +++ b/fs/btrfs/extent_io.h >>> @@ -205,7 +205,7 @@ struct extent_buffer { >>> */ >>> struct extent_changeset { >>> /* How many bytes are set/cleared in this operation */ >>> - u64 bytes_changed; >>> + unsigned int bytes_changed; >> >> The alignment constraints will insert 4 bytes anyway, so we don't save >> any space, but unsigned int is fine here, as we're not going to >> utilize u64. > > Sorry, I just realized that extent_state in extent_io_tree can be merged > with each other. > > So (state->end - state->start + 1) can overflow unsigned int. Please ignore this comment. In context of btrfs_qgroup_reserve_data(), we won't modify ranges out of the data extent, which is no larger than 128M. And all related extent_changeset users are all based on actually allocated extent, so we won't overflow unsigned int any way. Thanks, Qu > > I'll skip this modification in next update, and apply the grammar comment. > > Thanks, > Qu > >> >>> /* Changed ranges */ >>> struct ulist range_changed; >>> diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c >>> index 9f01c25469f7..ad2e99491395 100644 >>> --- a/fs/btrfs/qgroup.c >>> +++ b/fs/btrfs/qgroup.c >>> @@ -2886,6 +2886,7 @@ static int __btrfs_qgroup_release_data(struct >>> inode *inode, u64 start, u64 len, >>> btrfs_qgroup_free_refroot(BTRFS_I(inode)->root->fs_info, >>> BTRFS_I(inode)->root->objectid, >>> changeset.bytes_changed); >>> + ret = changeset.bytes_changed; >>> out: >>> ulist_release(&changeset.range_changed); >>> return ret; >>> -- >>> 2.12.2 >>> >>> >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe >>> linux-btrfs" in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >>