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[209.132.180.67]) by mx.google.com with ESMTP id bg5si24583237plb.458.2017.11.27.23.26.57; Mon, 27 Nov 2017 23:27:09 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751690AbdK1HZA convert rfc822-to-8bit (ORCPT + 78 others); Tue, 28 Nov 2017 02:25:00 -0500 Received: from prv-mh.provo.novell.com ([137.65.248.74]:55662 "EHLO prv-mh.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751313AbdK1HY7 (ORCPT ); Tue, 28 Nov 2017 02:24:59 -0500 Received: from INET-PRV-MTA by prv-mh.provo.novell.com with Novell_GroupWise; Tue, 28 Nov 2017 00:24:58 -0700 Message-Id: <5A1D7FC2020000F90009AD91@prv-mh.provo.novell.com> X-Mailer: Novell GroupWise Internet Agent 14.2.2 Date: Tue, 28 Nov 2017 00:24:50 -0700 From: "Gang He" To: , , , "Goldwyn Rodrigues" , Cc: , Subject: Re: [Ocfs2-devel] [PATCH 2/3] ocfs2: add ocfs2_overwrite_io function References: <1511775987-841-1-git-send-email-ghe@suse.com> <1511775987-841-3-git-send-email-ghe@suse.com> <123f1322-d453-4aca-ac95-63d6f90fd8a2@gmail.com> <5A1D49E5020000F90009AC66@prv-mh.provo.novell.com> <805fb849-dcc7-cbbc-02af-1c6116a88957@gmail.com> In-Reply-To: <805fb849-dcc7-cbbc-02af-1c6116a88957@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Joseph, >>> > > On 17/11/28 11:35, Gang He wrote: >> Hello Joseph, >> >> >>>>> >>> Hi Gang, >>> >>> On 17/11/27 17:46, Gang He wrote: >>>> Add ocfs2_overwrite_io function, which is used to judge if >>>> overwrite allocated blocks, otherwise, the write will bring extra >>>> block allocation overhead. >>>> >>>> Signed-off-by: Gang He >>>> --- >>>> fs/ocfs2/extent_map.c | 67 >>> +++++++++++++++++++++++++++++++++++++++++++++++++++ >>>> fs/ocfs2/extent_map.h | 3 +++ >>>> 2 files changed, 70 insertions(+) >>>> >>>> diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c >>>> index e4719e0..98bf325 100644 >>>> --- a/fs/ocfs2/extent_map.c >>>> +++ b/fs/ocfs2/extent_map.c >>>> @@ -832,6 +832,73 @@ int ocfs2_fiemap(struct inode *inode, struct >>> fiemap_extent_info *fieinfo, >>>> return ret; >>>> } >>>> >>>> +/* Is IO overwriting allocated blocks? */ >>>> +int ocfs2_overwrite_io(struct inode *inode, u64 map_start, u64 map_len, >>>> + int wait) >>>> +{ >>>> + int ret = 0, is_last; >>>> + u32 mapping_end, cpos; >>>> + struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); >>>> + struct buffer_head *di_bh = NULL; >>>> + struct ocfs2_extent_rec rec; >>>> + >>>> + if (wait) >>>> + ret = ocfs2_inode_lock(inode, &di_bh, 0); >>>> + else >>>> + ret = ocfs2_try_inode_lock(inode, &di_bh, 0); >>>> + if (ret) >>>> + goto out; >>>> + >>>> + if (wait) >>>> + down_read(&OCFS2_I(inode)->ip_alloc_sem); >>>> + else { >>>> + if (!down_read_trylock(&OCFS2_I(inode)->ip_alloc_sem)) { >>>> + ret = -EAGAIN; >>>> + goto out_unlock1; >>>> + } >>>> + } >>>> + >>>> + if ((OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) && >>>> + ((map_start + map_len) <= i_size_read(inode))) >>>> + goto out_unlock2; >>>> + >>>> + cpos = map_start >> osb->s_clustersize_bits; >>>> + mapping_end = ocfs2_clusters_for_bytes(inode->i_sb, >>>> + map_start + map_len); >>>> + is_last = 0; >>>> + while (cpos < mapping_end && !is_last) { >>>> + ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos, >>>> + NULL, &rec, &is_last); >>>> + if (ret) { >>>> + mlog_errno(ret); >>>> + goto out_unlock2; >>>> + } >>>> + >>>> + if (rec.e_blkno == 0ULL) >>>> + break; >>>> + >>>> + if (rec.e_flags & OCFS2_EXT_REFCOUNTED) >>>> + break; >>>> + >>>> + cpos = le32_to_cpu(rec.e_cpos) + >>>> + le16_to_cpu(rec.e_leaf_clusters); >>>> + } >>>> + >>>> + if (cpos < mapping_end) >>>> + ret = 1; >>>> + >>>> +out_unlock2: >>>> + brelse(di_bh); >>>> + >>>> + up_read(&OCFS2_I(inode)->ip_alloc_sem); >>>> + >>>> +out_unlock1: >>> Should brelse(di_bh) be here? >> If the code jumps to out_unlock1 directly, the di_bh pointer should be NULL, > it is not necessary to release. >> > Umm... No, once going out here, we have already taken inode lock. So > di_bh should be released. Sorry, you are right. > >>> >>>> + ocfs2_inode_unlock(inode, 0); >>>> + >>>> +out: >>>> + return (ret ? 0 : 1); >>> I don't think EAGAIN and other error code can be handled the same. We >>> have to distinguish them. >> Ok, I think we can add one line log to report the error in case the error is > not EAGAIN. >> > My point is, there is no need to try again in several cases, e.g. EROFS > returned by ocfs2_get_clusters_nocache. In this function ocfs2_overwrite_io() only can return True(1) or False(0), then I think we can only give a error print before return true/false. It is not necessary to return another value, but should let the user know any possible error message. Thanks Gang > >>> >>> Thanks, >>> Joseph >>> >>>> +} >>>> + >>>> int ocfs2_seek_data_hole_offset(struct file *file, loff_t *offset, int >>> whence) >>>> { >>>> struct inode *inode = file->f_mapping->host; >>>> diff --git a/fs/ocfs2/extent_map.h b/fs/ocfs2/extent_map.h >>>> index 67ea57d..fd9e86a 100644 >>>> --- a/fs/ocfs2/extent_map.h >>>> +++ b/fs/ocfs2/extent_map.h >>>> @@ -53,6 +53,9 @@ int ocfs2_extent_map_get_blocks(struct inode *inode, u64 >>> v_blkno, u64 *p_blkno, >>>> int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, >>>> u64 map_start, u64 map_len); >>>> >>>> +int ocfs2_overwrite_io(struct inode *inode, u64 map_start, u64 map_len, >>>> + int wait); >>>> + >>>> int ocfs2_seek_data_hole_offset(struct file *file, loff_t *offset, int >>> origin); >>>> >>>> int ocfs2_xattr_get_clusters(struct inode *inode, u32 v_cluster, >>>> >> From 1585291690621964331@xxx Tue Nov 28 06:52:49 +0000 2017 X-GM-THRID: 1585212205986077742 X-Gmail-Labels: Inbox,Category Forums,HistoricalUnread